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https://en.wikipedia.org/wiki/Need%20to%20know
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The term "need to know", when used by government and other organizations (particularly those related to the military or espionage), describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one has all the necessary official approvals (such as a security clearance) to access certain information, one would not be given access to such information, or read into a clandestine operation, unless one has a specific need to know; that is, access to the information must be necessary for one to conduct one's official duties. This term also includes anyone that the people with the knowledge deemed necessary to share it with.
As with most security mechanisms, the aim is to make it difficult for unauthorized access to occur, without inconveniencing legitimate access. Need-to-know also aims to discourage "browsing" of sensitive material by limiting access to the smallest possible number of people.
Examples
The Battle of Normandy in 1944 is an example of a need-to-know restriction. Though thousands of military personnel were involved in planning the invasion, only a small number of them knew the entire scope of the operation; the rest were only informed of data needed to complete a small part of the plan. The same is true of the Trinity project, the first test of a nuclear weapon in 1945.
Problems and criticism
Like other security measures, need to know can be misused by persons who wish to refuse others access to information they hold in an attempt to increase their personal power, prevent unwelcome review of their work, prevent embarrassment resulting from actions or thoughts.
Need to know can also be invoked to hide extra-legal activities. This may be considered a necessary use, or a detrimental abuse of such a policy when considered from different perspectives.
Need to know can be detrimental to workers' efficiency. Even when done in good faith, one might not be fully aware of who actually needs to know the informatio
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https://en.wikipedia.org/wiki/Effects%20loop
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An effects loop is a series of audio effects units, connected between two points of a signal path (the route that a signal would travel from the input to the output); usually between the pre-amp and power amp stages of an amplifier circuit, although occasionally between two pre-amp stages. The two principal uses of effects loops are in recordings and in instrument amplifiers.
There are two main advantages of an effects loop. The first is that generally effects sound clearer and are more pronounced when the input signal is sent through a preamplifier prior to being affected. In addition to this, the tone of a guitar amplifier is generally more defined if the guitar is going direct into the input of the preamplifier. The second advantage is to match impedances of equipment. For example, most guitar rack equipment works better at line-level, and not instrument level. By placing the effects after the preamp, signal loss due to impedance mismatch is avoided.
Most guitarists use floor pedal effects between the guitar and the amplifier, or they use rack effects through the amplifier effects loop. Some amplifier manufacturers have been including a level/gain control with the effects loops to allow for the use of floor pedals through the effects loop, rather than in-line between the guitar and amplifier. This allows for more tonal control of the amplifier.
See also
Effects unit
Audio amplifier
Guitar
Audio effects
Electrical signal connectors
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https://en.wikipedia.org/wiki/Reabsorption
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In renal physiology, reabsorption or tubular reabsorption is the process by which the nephron removes water and solutes from the tubular fluid (pre-urine) and returns them to the circulating blood. It is called reabsorption (and not absorption) because these substances have already been absorbed once (particularly in the intestines) and the body is reclaiming them from a postglomerular fluid stream that is on its way to becoming urine (that is, they will soon be lost to the urine unless they are reabsorbed from the tubule into the peritubular capillaries. This happens as a result of sodium transport from the lumen into the blood by the Na+/K+ATPase in the basolateral membrane of the epithelial cells. Thus, the glomerular filtrate becomes more concentrated, which is one of the steps in forming urine. Nephrons are divided into five segments, with different segments responsible for reabsorbing different substances. Reabsorption allows many useful solutes (primarily glucose and amino acids), salts and water that have passed through Bowman's capsule, to return to the circulation. These solutes are reabsorbed isotonically, in that the osmotic potential of the fluid leaving the proximal convoluted tubule is the same as that of the initial glomerular filtrate. However, glucose, amino acids, inorganic phosphate, and some other solutes are reabsorbed via secondary active transport through cotransport channels driven by the sodium gradient.
Renin–angiotensin system:
The kidneys sense low blood pressure.
Release renin into the blood.
Renin causes production of angiotensin I.
Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II.
Angiotensin II stimulates the release of aldosterone, ADH, and thirst.
Aldosterone causes kidneys to reabsorb sodium; ADH increases the uptake of water.
Water follows sodium.
As blood volume increases, pressure also increases.
See also
Transepithelial potential difference driving reabsorption
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https://en.wikipedia.org/wiki/QVT
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QVT (Query/View/Transformation) is a standard set of languages for model transformation defined by the Object Management Group.
Overview
Model transformation is a key technique used in model-driven architecture. As the name QVT indicates, the OMG standard covers transformations, views and queries together. Model queries and model views can be seen as special kinds of model transformation, provided that we use a suitably broad definition of model transformation: a model transformation is a program which operates on models.
The QVT standard defines three model transformation languages. All of them operate on models which conform to Meta-Object Facility (MOF) 2.0 metamodels; the transformation states which metamodels are used. A transformation in any of the three QVT languages can itself be regarded as a model, conforming to one of the metamodels specified in the standard. The QVT standard integrates the OCL 2.0 standard and also extends it with imperative features.
QVT-Operational is an imperative language designed for writing unidirectional transformations.
QVT-Relations is a declarative language designed to permit both unidirectional and bidirectional model transformations to be written. A transformation embodies a consistency relation on sets of models. Consistency can be checked by executing the transformation in checkonly mode; the transformation then returns True if the set of models is consistent according to the transformation and False otherwise. The same transformation can be used in enforce mode to attempt to modify one of the models so that the set of models will be consistent. The QVT-Relations language has both a textual and a graphical concrete syntax.
QVT-Core is a declarative language designed to be simple and to act as the target of translation from QVT-Relations. However, QVT-Core has never had a full implementation and in fact it is not as expressive as QVT-Relations. Hence the QVT Architecture pictured above is misleading: the transformati
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https://en.wikipedia.org/wiki/Frontoethmoidal%20suture
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The frontoethmoidal suture is the suture between the ethmoid bone and the frontal bone.
It is located in the anterior cranial fossa.
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https://en.wikipedia.org/wiki/Bandwidth%20management
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Bandwidth management is the process of measuring and controlling the communications (traffic, packets) on a network link, to avoid filling the link to capacity or overfilling the link, which would result in network congestion and poor performance of the network. Bandwidth is described by bit rate and measured in units of bits per second (bit/s) or bytes per second (B/s).
Bandwidth management mechanisms and techniques
Bandwidth management mechanisms may be used to further engineer performance and includes:
Traffic shaping (rate limiting):
Token bucket
Leaky bucket
TCP rate control - artificially adjusting TCP window size as well as controlling the rate of ACKs being returned to the sender
Scheduling algorithms:
Weighted fair queuing (WFQ)
Class based weighted fair queuing
Weighted round robin (WRR)
Deficit weighted round robin (DWRR)
Hierarchical Fair Service Curve (HFSC)
Congestion avoidance:
RED, WRED - Lessens the possibility of port queue buffer tail-drops and this lowers the likelihood of TCP global synchronization
Policing (marking/dropping the packet in excess of the committed traffic rate and burst size)
Explicit congestion notification
Buffer tuning - allows you to modify the way a router allocates buffers from its available memory, and helps prevent packet drops during a temporary burst of traffic.
Bandwidth reservation protocols / algorithms
Resource reservation protocol (RSVP) - is the means by which applications communicate their requirements to the network in an efficient and robust manner.
Constraint-based Routing Label Distribution Protocol (CR-LDP)
Top-nodes algorithm
Traffic classification - categorising traffic according to some policy in order that the above techniques can be applied to each class of traffic differently
Link performance
Issues which may limit the performance of a given link include:
TCP determines the capacity of a connection by flooding it until packets start being dropped (slow start)
Qu
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https://en.wikipedia.org/wiki/Gainclone
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Gainclone or chipamp is a type of audio amplifier made by do-it-yourselfers, or individuals interested in DIY audio. It is a design based on high-power integrated circuits, particularly the National Semiconductor Overture series. The Gainclone is probably the most commonly built and well-known amplifier project amongst hobbyists. It is simple to build and involves only a few readily accessible, inexpensive parts. As an amplifier, it is highly regarded by many in the DIY community.
Background
In 1999, 47 Labs introduced the Gaincard amplifier. The Gaincard shook the audiophile community with its unconventional design. It had fewer parts, less capacitance, and simpler construction than virtually anything preceding it, and relied for amplification on a chip, the National Semiconductor LM3875. These construction techniques went against the accepted wisdom of the time, which favored large power supplies and discrete component construction. This Gaincard was estimated to cost less than in parts, but it sold for with its small power supply. Controversy ensued after a number of positive reviews.
Modern usage
The DIY community started building replicas or "clones" of the Gaincard using integrated circuits from National Semiconductor and other manufacturers in an attempt to see if good sound could be obtained, thereby the term: "gainclone". The name was first coined by a poster called "triodont" (Ramon Salamat) on the popular Audio Asylum board (ca. 1999;). "Triodont" tried to replicate the 47 Labs Gaincard amplifier for his own personal use and reported about it on the internet forum. Various modifications or improvements have been made to the original application circuit found in National's design notes since. The simple circuits were easy to make, and some started offering printed circuit boards and kits to make construction even easier.
The design concept has expanded and become rapidly more popular over the last few years as the simplicity of the design and avail
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https://en.wikipedia.org/wiki/INASP
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INASP (International Network for Advancing Science and Policy) is an international development charity working with a global network of partners to improve access, production and use of research information and knowledge, so that countries are equipped to solve their development challenges.
Based in Oxford and governed by an international Board of Trustees, INASP is run with a small number of full-time staff working with, and through, partners and networks in over one hundred countries. INASP's work is funded by its partner countries, governmental and non-governmental development agencies, and philanthropic foundations.
History
INASP original name, now superseded, was "International Network for the Availability of Scientific Publications".
It was established by the International Council for Science (ICSU) in 1992 to "improve access to information and knowledge through a commitment to capacity building in emerging and developing countries."
It was registered as a charity in 2004.
Work
INASP is an international development charity working with a global network of partners to improve access, production and use of research information and knowledge, so that countries are equipped to solve their development challenges
INASP has over 30 years of experience of working across research and knowledge systems in Africa, Latin America, and Asia. INASP believes that locally generated knowledge and solutions are key to solving local and global challenges. Their vision is of research and knowledge at the heart of development – where decisions are informed by relevant and rigorous evidence, and where knowledge is created with the communities it is intended to serve. Many voices, institutions, and types of knowledge are required.
INASP works in partnership with people and organisations who produce, communicate, and use knowledge to strengthen key capacities and confidence. Their work aims to support individuals with fewer opportunities, to reach beyond apex institutions,
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https://en.wikipedia.org/wiki/Sphenozygomatic%20suture
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The sphenozygomatic suture is the cranial suture between the sphenoid bone and the zygomatic bone.
Additional images
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https://en.wikipedia.org/wiki/Sphenoparietal%20suture
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The sphenoparietal suture is the cranial suture between the sphenoid bone and the parietal bone. It is one of the sutures that comprises the pterion.
Additional images
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https://en.wikipedia.org/wiki/Sphenofrontal%20suture
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The sphenofrontal suture is the cranial suture between the sphenoid bone and the frontal bone.
Additional images
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https://en.wikipedia.org/wiki/Sphenopetrosal%20fissure
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The sphenopetrosal fissure (or sphenopetrosal suture) is the cranial suture between the sphenoid bone and the petrous portion of the temporal bone.
It is in the middle cranial fossa.
External links
Skull
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https://en.wikipedia.org/wiki/Zygomaticofrontal%20suture
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The zygomaticofrontal suture (or frontozygomatic suture) is the cranial suture between the zygomatic bone and the frontal bone. The suture can be palpated just lateral to the eye.
Additional images
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https://en.wikipedia.org/wiki/Zygomaticotemporal%20suture
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The zygomaticotemporal suture (or temporozygomatic suture) is the cranial suture between the zygomatic bone and the temporal bone. This is part of the zygomatic arch. Movement at the suture decreases with development during aging. It has a complex internal structure.
Additional images
See also
Zygomatic arch
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https://en.wikipedia.org/wiki/Sphenoethmoidal%20suture
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The sphenoethmoidal suture is the cranial suture between the sphenoid bone and the ethmoid bone.
It is located in the anterior cranial fossa.
External links
Bones of the head and neck
Cranial sutures
Human head and neck
Joints
Joints of the head and neck
Skeletal system
Skull
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https://en.wikipedia.org/wiki/Arthur%20Rubin
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Arthur Leonard Rubin (born 1956) is an American mathematician and aerospace engineer. He was named a Putnam Fellow on four consecutive occasions from 1970 to 1973.
Life and career
Rubin's mother was Jean E. Rubin, a professor of mathematics at Purdue University, and his father was Herman Rubin, a professor of statistics at the same university. Arthur co-authored his first paper with his mother in 1969 at the age of 13. He earned his Ph.D. at the California Institute of Technology in 1978, under the direction of Alexander S. Kechris.
Rubin unsuccessfully stood as a Libertarian to represent the 55th district in the 1984 California State Assembly elections.
Awards and honors
As an undergraduate, Rubin was named a Putnam Fellow on four occasions, the first time in 1970, aged 14, making him the youngest Fellow to date. In 1972, he tied for third place in the first USA Mathematical Olympiad.
In 1974, Rubin was the subject of an article in the Madison Capital Times, in which his Caltech undergraduate advisor was quoted as saying that someone of Rubin's ability appeared in the United States "about once in every ten years".
Publications
Rubin's dissertation was entitled Free Algebras in Von Neumann–Bernays–Gödel Set Theory and Positive Elementary Inductions in Reasonable Structures. In 1979, Rubin co-authored a paper on list coloring of graphs with Paul Erdős, giving him an Erdős number of 1.
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https://en.wikipedia.org/wiki/Occipitomastoid%20suture
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The occipitomastoid suture or occipitotemporal suture is the cranial suture between the occipital bone and the mastoid portion of the temporal bone.
It is continuous with the lambdoidal suture.
See also
Jugular foramen
Additional images
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https://en.wikipedia.org/wiki/Glue%20logic
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In electronics, glue logic is the custom logic circuitry used to interface a number of off-the-shelf integrated circuits. This is often achieved using common, inexpensive 7400- or 4000-series components. In more complex cases, a programmable logic device like a CPLD or FPGA might be used. The falling price of programmable logic devices, combined with their reduced size and power consumption compared to discrete components, is making them common even for simple systems. In addition, programmable logic can be used to hide the exact function of a circuit, in order to prevent a product from being cloned or counterfeited.
The software equivalent of glue logic is called glue code.
Usage
Typical functions of glue logic may include:
Simple logic functions.
Address decoding circuitry used with older processors like the MOS Technology 6502 or Zilog Z80 to divide up the processor's address space into RAM, ROM and I/O. Newer versions of these processors, such as the WDC 65816 or the Zilog eZ80, may add features that enable glueless interfacing to external devices.
Buffers to protect outputs from overload, or protect sensitive inputs from electrostatic discharge damage.
Voltage level conversion, e.g., when interfacing one logic family (CMOS) to another (TTL).
See also
Glue code
Reverse engineering
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https://en.wikipedia.org/wiki/CTIA%20%28organization%29
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CTIA is a trade association representing the wireless communications industry in the United States. The association was established in 1984 and is headquartered in Washington, D.C. It is a 501(c)(6) nonprofit membership organization, and represents wireless carriers and suppliers, and manufacturers and providers of wireless products and services.
CTIA operates certification programs for the wireless industry and publishes wireless industry surveys. It has also sponsored various public service initiatives related to wireless.
It was initially known as the Cellular Telecommunications Industry Association until 2004, and later the Cellular Telecommunications and Internet Association. The organization has since operated under its initialism only, subtitled as CTIA – The Wireless Association until 2015.
History
CTIA was established in May 1984 as the Cellular Telecommunications Industry Association. In 2000, the organization merged with the Wireless Data Forum and became the Cellular Telecommunications and Internet Association. Its name was changed to CTIA—The Wireless Association in 2004.
Tom Wheeler served as chief executive officer (CEO) of CTIA from 1992 to 2004. He was appointed chairman of the Federal Communications Commission (FCC) by President Barack Obama and confirmed by the United States Senate in November 2013.
Steve Largent became president and CEO in November 2003, serving until 2014. Meredith Attwell Baker became CTIA's president and CEO in June 2014.
Issue advocacy
Spectrum
When Baker was named president and CEO, she identified spectrum as a policy priority. She has testified before United States Congress on the issue. In a March 2016 media call, Baker said the industry is ready to invest billions of dollars to fund spectrum and new infrastructure. She suggested the "spectrum pipeline should become a national priority" because "100 MHz of spectrum is equal to $30 billion to the economy and 1 million jobs."
In 2016, CTIA released reports outlining
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https://en.wikipedia.org/wiki/Petrosquamous%20suture
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The petrosquamous suture is a cranial suture between the petrous portion and the squama of the temporal bone. It forms the Koerner's septum. The petrous portion forms the medial component of the osseous margin, while the squama forms the lateral component. The anterolateral portion (squama) arises from the mesenchyme at 8 weeks of embryogenesis while the petromastoid portion develops later from a cartilaginous center at 6 months of fetal development.
In certain people, it can contain an emissary vein, referred to as the petrosquamosal sinus. Being aware of this anatomic variant with preoperative CT scanning can be important to prevent bleeding in certain types of otolaryngological surgeries. Some authors have theorized that a persistent venous sinus reflects an arrest in embryologic development.
See also
Petrotympanic fissure
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https://en.wikipedia.org/wiki/Sphenosquamosal%20suture
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The sphenosquamosal suture is a cranial suture between the sphenoid bone and the squama of the temporal bone.
Additional images
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https://en.wikipedia.org/wiki/Network%20traffic%20control
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In computer networking, network traffic control is the process of managing, controlling or reducing the network traffic, particularly Internet bandwidth, e.g. by the network scheduler. It is used by network administrators, to reduce congestion, latency and packet loss. This is part of bandwidth management. In order to use these tools effectively, it is necessary to measure the network traffic to determine the causes of network congestion and attack those problems specifically.
Network traffic control is an important subject in datacenters as it is necessary for efficient use of datacenter network bandwidth and for maintaining service level agreements.
Traffic shaping
Traffic shaping is the retiming (delaying) of packets (or frames) until they meet specified bandwidth and or burstiness limits. Since such delays involve queues that are nearly always finite and, once full, excess traffic is nearly always dropped (discarded), traffic shaping nearly always implies traffic policing as well.
Traffic policing
Traffic policing is the dropping (discarding) or reduction in priority (demoting) of packets (or frames) that exceed some specified bandwidth and or burstiness limit.
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https://en.wikipedia.org/wiki/List%20of%20Java%20virtual%20machines
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This article provides non-exhaustive lists of Java SE Java virtual machines (JVMs). It does not include every Java ME vendor. Note that Java EE runs on the standard Java SE JVM but that some vendors specialize in providing a modified JVM optimized for Java EE applications. Much Java development work takes place on Windows, Solaris, Linux, and FreeBSD, primarily with the Oracle JVMs. Note the further complication of different 32-bit/64-bit varieties.
The primary reference Java VM implementation is HotSpot, produced by Oracle Corporation and many other big and medium-sized companies (e.g. IBM, Redhat, Microsoft, Azul, SAP).
Free and open source implementations
Active
Codename One – uses the open source ParparVM
Eclipse OpenJ9 – open-source from IBM J9, for AIX, Linux (x86, Power, and Z), macOS, Windows, MVS, OS/400, Pocket PC, z/OS.
GraalVM – is based on HotSpot/OpenJDK, it has a polyglot feature, to transparently mix and match supported languages.
HotSpot – the open-source Java VM implementation by Oracle.
Jikes RVM (Jikes Research Virtual Machine) – research project. PPC and IA-32. Supports Apache Harmony and GNU Classpath libraries. Eclipse Public License.
leJOS – Robotics suite, a firmware replacement for Lego Mindstorms programmable bricks, provides a Java programming environment for the Lego Mindstorms RCX and NXT robots.
Maxine – meta-circular open source research VM from Oracle Labs and the University of Manchester.
Inactive
Apache Harmony – supports several architectures and systems. Discontinued November 2011. Apache License 2.0.
GCJ the GCC Java compiler, that compiles either to bytecode or to native machine code. As of GCC 7, gcj and associated libjava runtime library have been removed from GCC.
IKVM.NET – Java for Mono and the Microsoft .NET Framework. Uses OpenJDK. Zlib License.
JamVM – developed to be an extremely small virtual machine. Uses GNU Classpath and OpenJDK. Supports several architectures. GPL. Last update 2014.
JOP – hardwar
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https://en.wikipedia.org/wiki/Proper%20frame
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A proper frame, or comoving frame, is a frame of reference that is attached to an object. The object in this frame is stationary within the frame, which is useful for many types of calculations.
For example, a freely falling elevator is a proper frame for a free-falling object in the elevator, while the surface of the Earth is not. But, for an object on the Earth's surface, the Earth's surface is a proper frame while the falling elevator is not a proper frame. Proper frames can be inertial and non-inertial, as in the example above.
The use of a proper frame is essential for the investigation of physical laws within the framework of general relativity.
The term comoving frame is also a good description of a non-inertial frame, which is useful for many of the same uses as we mentioned previously. One advantage of proper frame and comoving frame is that the two frames must always maintain the same spatial position (i. "in the frame" - e.g. on the same frame of reference). This includes that the frame must always be in position in the spacetime frame and thus the spacetime can be viewed as having "no axis". As our first example of a proper frame, one uses the following frame to find the Earth:
The Earth is situated in the center with respect to the observer (or our point of reference) of our next example, the Sun is at the bottom.
𝜕 is described as the set of sets that have the property that the motion vectors of an object are conserved. 𝜕 can be thought of as the set of sets (including proper frames) of all possible motions of a given object, such that a proper frame always results.
In quantum field theory and many fields of physics, such as electromagnetism, it is often referred to as the "comoving frame" of a particle. 𝜕 can be thought of as the unique set of frames that are conserved under gravity, allowing that the particles of gravitation do not collapse on an object after the initial contact (for example, they remain in the frame they have been suspended in
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https://en.wikipedia.org/wiki/Database%20forensics
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Database forensics is a branch of digital forensic science relating to the forensic study of databases and their related metadata.
The discipline is similar to computer forensics, following the normal forensic process and applying investigative techniques to database contents and metadata. Cached information may also exist in a servers RAM requiring live analysis techniques.
A forensic examination of a database may relate to the timestamps that apply to the update time of a row in a relational table being inspected and tested for validity in order to verify the actions of a database user. Alternatively, a forensic examination may focus on identifying transactions within a database system or application that indicate evidence of wrongdoing, such as fraud.
Software tools can be used to manipulate and analyse data. These tools also provide audit logging capabilities which provide documented proof of what tasks or analysis a forensic examiner performed on the database.
Currently many database software tools are in general not reliable and precise enough to be used for forensic work as demonstrated in the first paper published on database forensics.
There is currently a single book published in this field, though more are destined.
Additionally there is a subsequent SQL Server forensics book by Kevvie Fowler named SQL Server Forensics which is well regarded also.
The forensic study of relational databases requires a knowledge of the standard used to encode data on the computer disk. A documentation of standards used to encode information in well-known brands of DB such as SQL Server and Oracle has been contributed to the public domain. Others include Apex Analytix.
Because the forensic analysis of a database is not executed in isolation, the technological framework within which a subject database exists is crucial to understanding and resolving questions of data authenticity and integrity especially as it relates to database users.
Further reading
Farmer and Ven
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https://en.wikipedia.org/wiki/Financial%20risk%20modeling
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Financial risk modeling is the use of formal mathematical and econometric techniques to measure, monitor and control the market risk, credit risk, and operational risk on a firm's balance sheet, on a bank's trading book, or re a fund manager's portfolio value; see Financial risk management.
Risk modeling is one of many subtasks within the broader area of financial modeling.
Application
Risk modeling uses a variety of techniques including market risk, value at risk (VaR), historical simulation (HS), or extreme value theory (EVT) in order to analyze a portfolio and make forecasts of the likely losses that would be incurred for a variety of risks. As above, such risks are typically grouped into credit risk, market risk, model risk, liquidity risk, and operational risk categories.
Many large financial intermediary firms use risk modeling to help portfolio managers assess the amount of capital reserves to maintain, and to help guide their purchases and sales of various classes of financial assets.
Formal risk modeling is required under the Basel II proposal for all the major international banking institutions by the various national depository institution regulators. In the past, risk analysis was done qualitatively but now with the advent of powerful computing software, quantitative risk analysis can be done quickly and effortlessly.
Criticism
Modeling the changes by distributions with finite variance is now known to be inappropriate. Benoît Mandelbrot found in the 1960s that changes in prices in financial markets do not follow a Gaussian distribution, but are rather modeled better by Lévy stable distributions. The scale of change, or volatility, depends on the length of the time interval to a power a bit more than 1/2. Large changes up or down, also called fat tails, are more likely than what one would calculate using a Gaussian distribution with an estimated standard deviation.
Quantitative risk analysis and its modeling have been under question in the light
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https://en.wikipedia.org/wiki/Cyclopiazonic%20acid
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Cyclopiazonic acid (α-CPA), a mycotoxin and a fungal neurotoxin, is made by the molds Aspergillus and Penicillium. It is an indole-tetramic acid that serves as a toxin due to its ability to inhibit calcium-dependent ATPases found in the endoplasmic and sarcoplasmic reticulum. This inhibition disrupts the muscle contraction-relaxation cycle and the calcium gradient that is maintained for proper cellular activity in cells.
Cyclopiazonic acid is known to contaminate multiple foods because the molds that produce them are able to grow on different agricultural products, including but not limited to grains, corn, peanuts, and cheese. Due to this contamination, α-CPA can be harmful to both humans and farm animals that were exposed to contaminated animal feeds. However, α-CPA needs to be introduced in very high concentrations to produce mycotoxicosis in animals. Due to this, α-CPA is not a potent acute toxin.
Chemically, CPA is related to ergoline alkaloids. CPA was originally isolated from Penicillium cyclopium and subsequently from other fungi including Penicillium griseofulvum, Penicillium camemberti, Penicillium commune, Aspergillus flavus, and Aspergillus versicolor. CPA only appears to be toxic in high concentrations. Ingestion of CPA causes anorexia, dehydration, weight loss, immobility, and signs of spasm when near death. CPA can be found in molds, corns, peanuts, and other fermented products, such as cheese and sausages. Biologically, CPA is a specific inhibitor of SERCA ATPase in intracellular Ca2+ storage sites. CPA inhibits SERCA ATPase by keeping it in one specific conformation, thus, preventing it from forming another. CPA also binds to SERCA ATPase at the same site as another inhibitor, thapsigargin (TG). In this way, CPA lowers the ability of SERCA ATPase to bind an ATP molecule.
Toxicity
Cases of α-CPA mycotoxicosis in humans are rare. However, the occurrence of α-CPA in foods consumed by humans suggests that the toxin is indeed ingested by humans, tho
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https://en.wikipedia.org/wiki/RICE%20chart
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An ICE table or RICE box or RICE chart is a tabular system of keeping track of changing concentrations in an equilibrium reaction. ICE stands for initial, change, equilibrium. It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. Some sources refer to a RICE table (or box or chart) where the added R stands for the reaction to which the table refers. Others simply call it a concentration table (for the acid–base equilibrium).
Example
To illustrate the processes, consider the case of dissolving a weak acid, HA, in water. The pH can be calculated using an ICE table. Note that in this example, we are assuming that the acid is not very weak, and that the concentration is not very dilute, so that the concentration of [OH−] ions can be neglected. This is equivalent to the assumption that the final pH will be below about 6 or so. See pH calculations for more details.
First write down the equilibrium expression.
HA <=> {A^-} + {H+}
The columns of the table correspond to the three species in equilibrium.
The first row shows the reaction, which some authors label R and some leave blank.
The second row, labeled I, has the initial conditions: the nominal concentration of acid is Ca and it is initially undissociated, so the concentrations of A− and H+ are zero.
The third row, labeled C, specifies the change that occurs during the reaction. When the acid dissociates, its concentration changes by an amount , and the concentrations of A− and H+ both change by an amount . This follows from consideration of mass balance (the total number of each atom/molecule must remain the same) and charge balance (the sum of the electric charges before and after the reaction must be zero).
Note that the coefficients in front of the "x" correlate to the mole ratios of the reactants to the product. For example, if the reaction equation had 2 H+ ions in the product, then the "change"
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https://en.wikipedia.org/wiki/Buzen%27s%20algorithm
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In queueing theory, a discipline within the mathematical theory of probability, Buzen's algorithm (or convolution algorithm) is an algorithm for calculating the normalization constant G(N) in the Gordon–Newell theorem. This method was first proposed by Jeffrey P. Buzen in his 1971 PhD dissertation and subsequently published in a refereed journal in 1973. Computing G(N) is required to compute the stationary probability distribution of a closed queueing network.
Performing a naïve computation of the normalizing constant requires enumeration of all states. For a closed network with N circulating customers and M service facilities, G(N) is the sum of individual terms, with each term consisting of M factors raised to powers whose sum is N. Buzen's algorithm computes G(N) using only NM multiplications and NM additions. This dramatic improvement opened the door to applying the Gordon-Newell theorem to models of real world computer systems as well as flexible manufacturing systems and other cases where bottlenecks and queues can form within networks of inter-connected service facilities. The values of G(1), G(2) ... G(N -1), which can be used to calculate other important quantities of interest, are computed as by-products of the algorithm.
Problem setup
Consider a closed queueing network with M service facilities and N circulating customers. Assume that the service time for a customer at service facility i is given by an exponentially distributed random variable with parameter μi and that, after completing service at service facility i, a customer will proceed next to service facility j with probability pij.
Let be the steady state probability that the number of customers at service facility i is equal to ni for i = 1, 2, ... , M . It follows from the Gordon–Newell theorem that
....
This result is usually written more compactly as
The values of Xi are determined by solving
G(N) is a normalizing constant chosen so that the sum of all values of is equa
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https://en.wikipedia.org/wiki/Flyback%20converter
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The flyback converter is used in both AC/DC, and DC/DC conversion with galvanic isolation between the input and any outputs. The flyback converter is a buck-boost converter with the inductor split to form a transformer, so that the voltage ratios are multiplied with an additional advantage of isolation. When driving, for example, a plasma lamp or a voltage multiplier, the rectifying diode of the boost converter is left out and the device is called a flyback transformer.
Structure and principle
The schematic of a flyback converter can be seen in Fig. 1. It is equivalent to that of a buck-boost converter, with the inductor split to form a transformer. Therefore, the operating principle of both converters is very similar:
When the switch is closed (top of Fig. 2), the primary of the transformer is directly connected to the input voltage source. The primary current and magnetic flux in the transformer increases, storing energy in the transformer. The voltage induced in the secondary winding is negative, so the diode is reverse-biased (i.e., blocked). The output capacitor supplies energy to the output load.
When the switch is opened (bottom of Fig. 2), the primary current and magnetic flux drops. The secondary voltage is positive, forward-biasing the diode, allowing current to flow from the transformer. The energy from the transformer core recharges the capacitor and supplies the load.
The operation of storing energy in the transformer before transferring to the output of the converter allows the topology to easily generate multiple outputs with little additional circuitry, although the output voltages have to be able to match each other through the turns ratio. Also there is a need for a controlling rail which has to be loaded before load is applied to the uncontrolled rails, this is to allow the PWM to open up and supply enough energy to the transformer.
Operations
The flyback converter is an isolated power converter. The two prevailing control schemes are vo
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https://en.wikipedia.org/wiki/Wien%20approximation
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Wien's approximation (also sometimes called Wien's law or the Wien distribution law) is a law of physics used to describe the spectrum of thermal radiation (frequently called the blackbody function). This law was first derived by Wilhelm Wien in 1896. The equation does accurately describe the short-wavelength (high-frequency) spectrum of thermal emission from objects, but it fails to accurately fit the experimental data for long-wavelength (low-frequency) emission.
Details
Wien derived his law from thermodynamic arguments, several years before Planck introduced the quantization of radiation.
Wien's original paper did not contain the Planck constant. In this paper, Wien took the wavelength of black-body radiation and combined it with the Maxwell–Boltzmann energy distribution for atoms. The exponential curve was created by the use of Euler's number e raised to the power of the temperature multiplied by a constant. Fundamental constants were later introduced by Max Planck.
The law may be written as
(note the simple exponential frequency dependence of this approximation) or, by introducing natural Planck units,
where:
This equation may also be written as
where is the amount of energy per unit surface area per unit time per unit solid angle per unit wavelength emitted at a wavelength λ.
The peak value of this curve, as determined by setting the derivative of the equation equal to zero and solving, occurs at
a wavelength
and frequency
Relation to Planck's law
The Wien approximation was originally proposed as a description of the complete spectrum of thermal radiation, although it failed to accurately describe long-wavelength (low-frequency) emission. However, it was soon superseded by Planck's law, which accurately describes the full spectrum, derived by treating the radiation as a photon gas and accordingly applying Bose–Einstein in place of Maxwell–Boltzmann statistics. Planck's law may be given as
The Wien approximation may be derived from Planck'
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https://en.wikipedia.org/wiki/Gene%20cassette
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In biology, a gene cassette is a type of mobile genetic element that contains a gene and a recombination site. Each cassette usually contains a single gene and tends to be very small; on the order of 500–1000 base pairs. They may exist incorporated into an integron or freely as circular DNA. Gene cassettes can move around within an organism's genome or be transferred to another organism in the environment via horizontal gene transfer. These cassettes often carry antibiotic resistance genes. An example would be the kanMX cassette which confers kanamycin (an antibiotic) resistance upon bacteria.
Integrons
Integrons are genetic structures in bacteria which express and are capable of acquiring and exchanging gene cassettes. The integron consists of a promoter, an attachment site, and an integrase gene that encodes a site-specific recombinase There are three classes of integrons described. The mobile units that insert into integrons are gene cassettes. For cassettes that carry a single gene without a promoter, the entire series of cassettes is transcribed from an adjacent promoter within the integron. The gene cassettes are speculated to be inserted and excised via a circular intermediate. This would involve recombination between short sequences found at their termini and known as 59 base elements (59-be)—which may not be 59 bases long. The 59-be are a diverse family of sequences that function as recognition sites for the site-specific integrase (enzyme responsible for integrating the gene cassette into an integron) that occur downstream from the gene coding sequence.
Diversity and prevalence
The ability of genetic elements like gene cassettes to excise and insert into genomes results in highly similar gene regions appearing in distantly related organisms. The three classes of integrons are similar in structure and are identified by where the insertions occur and what systems they coincide with. Class 1 integrons are seen in a diverse group of bacterial genomes and
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https://en.wikipedia.org/wiki/Structure%20mapping%20engine
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In artificial intelligence and cognitive science, the structure mapping engine (SME) is an implementation in software of an algorithm for analogical matching based on the psychological theory of Dedre Gentner. The basis of Gentner's structure-mapping idea is that an analogy is a mapping of knowledge from one domain (the base) into another (the target). The structure-mapping engine is a computer simulation of the analogy and similarity comparisons.
The theory is useful because it ignores surface features and finds matches between potentially very different things if they have the same representational structure. For example, SME could determine that a pen is like a sponge because both are involved in dispensing liquid, even though they do this very differently.
Structure mapping theory
Structure mapping theory is based on the systematicity principle, which states that connected knowledge is preferred over independent facts. Therefore, the structure mapping engine should ignore isolated source-target mappings unless they are part of a bigger structure. The SME, the theory goes, should map objects that are related to knowledge that has already been mapped.
The theory also requires that mappings be done one-to-one, which means that no part of the source description can map to more than one item in the target and no part of the target description can be mapped to more than one part of the source. The theory also requires that if a match maps subject to target, the arguments of subject and target must also be mapped. If both these conditions are met, the mapping is said to be "structurally consistent."
Concepts in SME
SME maps knowledge from a source into a target. SME calls each description a dgroup. Dgroups contain a list of entities and predicates. Entities represent the objects or concepts in a description — such as an input gear or a switch. Predicates are one of three types and are a general way to express knowledge for SME.
Relation predicates contain mul
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https://en.wikipedia.org/wiki/Key%20clustering
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Key or hash function should avoid clustering, the mapping of two or more keys to consecutive slots. Such clustering may cause the lookup cost to skyrocket, even if the load factor is low and collisions are infrequent. The popular multiplicative hash is claimed to have particularly poor clustering behaviour.
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https://en.wikipedia.org/wiki/Leo%20the%20Lion%20%28MGM%29
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Leo the Lion is the mascot for the Hollywood film studio Metro-Goldwyn-Mayer and one of its predecessors, Goldwyn Pictures. The logo was created by artist Lionel S. Reiss, who served as art director at Paramount Pictures.
Since 1917, and through the time the studio was formed by the merger of Samuel Goldwyn's studio with Marcus Loew's Metro Pictures and Louis B. Mayer's company in 1924, several different lions have been used for the MGM logo.
Although MGM is referred to all of the lions used in their trademark as "Leo the Lion", only the lion in use since 1957 (a total of years), was actually named "Leo". In 2021, MGM introduced a new CGI logo which features a lion partially based on Leo.
History
Goldwyn Pictures lions (1917–1924)
The lion was chosen as the company's mascot in 1916 by publicist Howard Dietz, as a tribute to his alma mater Columbia University, whose mascot is a lion. Dietz was most directly inspired by the university's fight song, "Roar, Lion, Roar". Names of the first 2 lions used for the Goldwyn Pictures logos are unknown.
Slats (1924–1928)
Slats, trained by Volney Phifer, was the first lion used in the branding of the newly formed studio. Born at the Dublin Zoo on March 20, 1919, and originally named Cairbre (Gaelic for 'charioteer'), Slats was used on all black-and-white MGM films between 1924 and 1928. The first MGM film that used the logo was He Who Gets Slapped (1924).
Unlike his successors, Slats did nothing but look around in the logo, making him the only MGM lion not to roar. However, it is rumored that Phifer trained the lion to growl on cue, despite the fact that synchronized sound would not be used in motion pictures until 1927.
Slats died in 1936 when he was 17. At that time Phifer retired to his farm in Gillette, New Jersey, where he kept other animals used on Broadway. Upon his death, Phifer buried the lion on his farm and placed a plain block of granite to mark the grave. Later, Phifer planted a pine tree directly above th
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https://en.wikipedia.org/wiki/Ampullary%20cupula
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The ampullary cupula, or cupula, is a structure in the vestibular system, providing the sense of spatial orientation.
The cupula is located within the ampullae of each of the three semicircular canals. Part of the crista ampullaris, the cupula has embedded within it hair cells that have several stereocilia associated with each kinocilium. The cupula itself is the gelatinous component of the crista ampullaris that extends from the crista to the roof of the ampullae. When the head rotates, the endolymph filling the semicircular ducts initially lags behind due to inertia. As a result, the cupula is deflected opposite the direction of head movement. As the endolymph pushes the cupula, the stereocilia is bent as well, stimulating the hair cells within the crista ampullaris. After a short time of continual rotation however, the endolymph's acceleration normalizes with the rate of rotation of the semicircular ducts. As a result, the cupula returns to its resting position and the hair cells cease to be stimulated. This continues until the head stops rotating which simultaneously halts semicircular duct rotation. Due to inertia, however, the endolymph continues on. As the endolymph continues to move, the cupula is once again deflected resulting in the compensatory movements of the body when spun. In only the first situation, as fluid rushes by the cupula, the hair cells stimulated transmit the corresponding signal to the brain through the vestibulocochlear nerve (CN VIII). In the second one, there is no stimulation as the kinocilium can only be bent in one direction.
In their natural orientation within the head, the cupulae are located on the medial aspect of the semicircular canals. In this orientation, the kinocilia rest on the posterior aspect of the cupula.
Effects of alcohol
The Buoyancy Hypothesis posits that alcohol causes vertigo by affecting the neutral buoyancy of the cupula within the surrounding fluid called the endolymph. Linear accelerations (such as that
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https://en.wikipedia.org/wiki/Multiplicity%20function%20for%20N%20noninteracting%20spins
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The multiplicity function for a two state paramagnet, W(n,N), is the number of spin states such that n of the N spins point in the z-direction. This function is given by the combinatoric function C(N,n). That is:
It is primarily used in introductory statistical mechanics and thermodynamics textbooks to explain the microscopic definition of entropy to students. If the spins are non-interacting, then the multiplicity function counts the number of states which have the same energy in an external magnetic field. By definition, the entropy S is then given by the natural logarithm of this number:
Where k is the Boltzmann constant
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https://en.wikipedia.org/wiki/Doubly%20labeled%20water
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Doubly labeled water is water in which both the hydrogen and the oxygen have been partly or completely replaced (i.e. labeled) with an uncommon isotope of these elements for tracing purposes.
In practice, for both practical and safety reasons, almost all recent applications of the "doubly labeled water" method use water labeled with heavy but non-radioactive forms of each element (deuterium and oxygen-18). In theory, radioactive heavy isotopes of the elements could be used for such labeling; this was the case in many early applications of the method.
In particular, doubly labeled water (DLW) can be used for a method to measure the average daily metabolic rate of an organism over a period of time (often also called the Field metabolic rate, or FMR, in non-human animals). This is done by administering a dose of DLW, then measuring the elimination rates of deuterium and oxygen-18 in the subject over time (through regular sampling of heavy isotope concentrations in body water, by sampling saliva, urine, or blood). At least two samples are required: an initial sample (after the isotopes have reached equilibrium in the body), and a second sample some time later. The time between these samples depends on the size of the animal. In small animals, the period may be as short as 24 hours; in larger animals (such as adult humans), the period may be as long as 14 days.
The method was invented in the 1950s by Nathan Lifson and colleagues at the University of Minnesota. However, its use was restricted to small animals until the 1980s because of the high cost of the oxygen-18 isotope. Advances in mass spectrometry during the 1970s and early 1980s reduced the amount of isotope required, which made it feasible to apply the method to larger animals, including humans. The first application to humans was in 1982, by Dale Schoeller, over 25 years after the method was initially discovered. A complete summary of the technique is provided in a book by British biologist John Speakman.
Me
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https://en.wikipedia.org/wiki/Posterior%20sternoclavicular%20ligament
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The posterior sternoclavicular ligament is a band of fibers, covering the posterior surface of the sternoclavicular joint. It is attached above to the upper and back part of the sternal end of the clavicle, and, passing obliquely downward and medialward, is fixed below to the back of the upper part of the manubrium sterni.
It is in relation, in front, with the articular disk and synovial membranes; behind, with the Sternohyoideus and Sternothyreoideus.
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https://en.wikipedia.org/wiki/Deep%20auricular%20artery
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The deep auricular artery is a branch of the maxillary artery. The deep auricular artery pierces the external acoustic meatus. It provides arterial supply to the skin of the external acoustic meatus, and contributes arterial supply to the tympanic membrane, and (via a branch) the temporomandibular joint.
Anatomy
Origin
It is a branch of the (mandibular part of) the maxillary artery. It often arises in common with the anterior tympanic artery.
Course
It ascends in the substance of the parotid gland, behind the temporomandibular articulation, and pierces the cartilaginous or bony wall of the external acoustic meatus to course between the cartilage and bone.
Distribution
It supplies its cuticular lining and the outer surface of the tympanic membrane.
It gives a branch to the temporomandibular joint.
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https://en.wikipedia.org/wiki/Anterior%20tympanic%20artery
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The anterior tympanic artery (glaserian artery) is a branch of (the mandibular part of) the maxillary artery. It passes through the petrotympanic fissure to entre the middle ear where it contributes to the formation of the circular anastomosis around the tympanic membrane. It provides artieral supply to part of the lining of the middle ear. It is accompanied by the chorda tympani nerve.
Anatomy
Course and anastomoses
It passes upward behind the temporomandibular articulation, enters the tympanic cavity through the petrotympanic fissure, and ramifies upon the tympanic membrane, forming a vascular circle around the membrane with the stylomastoid branch of the posterior auricular, and anastomosing with the artery of the pterygoid canal and with the caroticotympanic branch from the internal carotid.
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https://en.wikipedia.org/wiki/Night%20owl
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A night owl, evening person or simply owl, is a person who tends or prefers to be active late at night and into the early morning, and to sleep and wake up later than is considered normal; night owls often work or engage in recreational activities late into the night (in some cases, until around dawn), and sleep until relatively late in the day.
The opposite of a night owl is an early bird – a lark as opposed to an owl – which is someone who tends to begin sleeping at a time that is considered early and also wakes early. Researchers traditionally use the terms morningness and eveningness for the two chronotypes or diurnality and nocturnality in animal behavior. In several countries, especially in Scandinavia, one who stays up late is called a B-person, in contrast to an early riser being called an A-person.
Involuntary and unwanted inability to fall asleep at an ordinary time may be diagnosed as delayed sleep phase disorder. However, many night owls do not consider their habits a disorder, and adapt their lifestyle accordingly; some choose to work in the evening or overnight. Other mays face challenges due to externally fixed schedules associated with their places of work or education.
History
While staying up after dark was considered a negative trait, this changed in 17th and 18th century Europe (and subsequently spread beyond) due to the development and implementation of artificial lighting: more domestic lights, added street lighting, and adaptation by the royal and upper social classes. The introduction of chocolate, coffee and tea, and cafes that stayed open through dawn, became part of the new culture.
Etymology
The term is derived from nocturnal habits of owls. Most owls sleep during the day and hunt for food at night.
Characteristics
Usually, people who are night owls stay awake past midnight, and extreme night owls may stay awake until just before or even after dawn.
Some night owls have a preference or habit for staying up late, or stay up to wor
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https://en.wikipedia.org/wiki/Infraorbital%20artery
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The infraorbital artery is a small artery in the head that arises from the maxillary artery and passes through the inferior orbital fissure to enter the orbit, then passes forward along the floor of the orbit, finally exiting the orbit through the infraorbital foramen to reach the face.
Anatomy
Origin
The infraorbital artery arises from the maxillary artery; it often arises in conjunction with the posterior superior alveolar artery. It may be considered a continuation of the third part of the maxillary artery and continues the direction of the maxillary artery.
Course
It passes anterior-ward to enter the orbit through the inferior orbital fissure. In the orbit, it courses along the floor of the orbit with the infraorbital nerve first along the infraorbital groove and then the infraorbital canal. It exits the orbit (with the infraorbital nerve) through infraorbital foramen to reach the face, beneath the infraorbital head of the levator labii superioris muscle.
Branches
While in the canal, it gives off:
Orbital branches - assist in supplying the inferior rectus and inferior oblique and the lacrimal sac.
Anterior superior alveolar artery - supplies upper/maxillary canine and incisor teeth.
Middle superior alveolar artery - upper/maxillary canine and incisor teeth. May be absent.
On the face, some branches pass upward to the medial angle of the orbit and the lacrimal sac, anastomosing with the angular artery, a branch of the facial artery; others run toward the nose, anastomosing with the dorsal nasal branch of the ophthalmic artery; and others descend between the levator labii superioris and the levator anguli oris, and anastomose with the facial artery, transverse facial artery, and buccal artery.
The four remaining branches arise from that portion of the maxillary artery which is contained in the pterygopalatine fossa.
Additional images
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https://en.wikipedia.org/wiki/Posterior%20superior%20alveolar%20artery
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The posterior superior alveolar artery (posterior dental artery) is a branch of the maxillary artery. It is one of two or three superior alveolar arteries. It provides arterial suply to the molar and premolar teeth, maxillary sinus and adjacent bone, and the gingiva.
Anatomy
Origin
The artery typically arises from maxillary artery within the pterygopalatine fossa. It frequently arises in conjunction with the infraorbital artery.
Course
It passes inferior-ward upon the infratemporal surface of maxilla before ramifying.
Branches
It emits branches that pass through foramina on the posterior aspect of the maxilla alongside the posterior superior alveolar nerves.
Some branches enter the alveolar canals to supply the upper molar and premolar teeth as well as the maxillary sinus and adjacent bone.
Some branches pass anterior-ward across the alveolar process to supply the gingiva.
See also
Anterior superior alveolar arteries
Posterior superior alveolar nerve
Additional images
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https://en.wikipedia.org/wiki/Neurite
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A neurite or neuronal process refers to any projection from the cell body of a neuron. This projection can be either an axon or a dendrite. The term is frequently used when speaking of immature or developing neurons, especially of cells in culture, because it can be difficult to tell axons from dendrites before differentiation is complete.
Neurite development
The development of a neurite requires a complex interplay of both extracellular and intracellular signals. At every given point along a developing neurite, there are receptors detecting both positive and negative growth cues from every direction in the surrounding space. The developing neurite sums together all of these growth signals in order to determine which direction the neurite will ultimately grow towards. While not all of the growth signals are known, several have been identified and characterized. Among the known extracellular growth signals are netrin, a midline chemoattractant, and semaphorin, ephrin and collapsin, all inhibitors of neurite growth.
Young neurites are often packed with microtubule bundles, the growth of which is stimulated by neurotrophic factors, such as nerve growth factor (NGF). Tau proteins can aid in the stabilization of microtubules by binding to the microtubules, protecting them from microtubule severing proteins. Even after the microtubules have stabilized, the cytoskeleton of the neuron remains dynamic. Actin filaments retain their dynamic properties in the neurite that will become the axon in order to push the microtubules bundles outward to extend the axon. In all other neurites however, the actin filaments are stabilized by myosin. This prevents the development of multiple axons.
The neural cell adhesion molecule N-CAM simultaneously combines with another N-CAM and a fibroblast growth factor receptor to stimulate the tyrosine kinase activity of that receptor to induce the growth of neurites.
There are several software kits available to facilitate neurite tracing in im
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https://en.wikipedia.org/wiki/Infratemporal%20fossa
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The infratemporal fossa is an irregularly shaped cavity that is a part of the skull. It is situated below and medial to the zygomatic arch. It is not fully enclosed by bone in all directions. It contains superficial muscles, including the lower part of the temporalis muscle, the lateral pterygoid muscle, and the medial pterygoid muscle. It also contains important blood vessels such as the middle meningeal artery, the pterygoid plexus, and the retromandibular vein, and nerves such as the mandibular nerve (CN V3) and its branches.
Structure
Boundaries
The boundaries of the infratemporal fossa occur:
anteriorly, by the infratemporal surface of the maxilla, and the ridge which descends from its zygomatic process. This contains the alveolar canal.
posteriorly, by the tympanic part of the temporal bone, and the spina angularis of the sphenoid.
superiorly, by the greater wing of the sphenoid below the infratemporal crest, and by the under surface of the temporal squama, containing the foramen ovale, which transmits the mandibular branch of the trigeminal nerve, and the foramen spinosum, which transmits the middle meningeal artery.
inferiorly, by the medial pterygoid muscle attaching to the mandible.
medially, by the lateral pterygoid plate.
laterally, by the ramus of mandible. This contains the mandibular foramen, leading to the mandibular canal through which the inferior alveolar nerve passes. This also contains the lingula, a triangular piece of bone that overlies the mandibular foramen antero-medially. Finally, the mylohyoid groove descends obliquely transmitting the mylohyoid nerve the only motor branch of the posterior division of the trigeminal nerve.
Contents
Muscles
Lower part of the temporalis muscle and masseter muscle (origin of masseter muscle:lower margin of the inner surface of zygomatic bone insertion : outer surface of the ramus of the mandible)
Lateral pterygoid muscle and medial pterygoid muscle.
Arteries
The infratemporal fossa contains
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https://en.wikipedia.org/wiki/Gene%20structure
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Gene structure is the organisation of specialised sequence elements within a gene. Genes contain most of the information necessary for living cells to survive and reproduce. In most organisms, genes are made of DNA, where the particular DNA sequence determines the function of the gene. A gene is transcribed (copied) from DNA into RNA, which can either be non-coding (ncRNA) with a direct function, or an intermediate messenger (mRNA) that is then translated into protein. Each of these steps is controlled by specific sequence elements, or regions, within the gene. Every gene, therefore, requires multiple sequence elements to be functional. This includes the sequence that actually encodes the functional protein or ncRNA, as well as multiple regulatory sequence regions. These regions may be as short as a few base pairs, up to many thousands of base pairs long.
Much of gene structure is broadly similar between eukaryotes and prokaryotes. These common elements largely result from the shared ancestry of cellular life in organisms over 2 billion years ago. Key differences in gene structure between eukaryotes and prokaryotes reflect their divergent transcription and translation machinery. Understanding gene structure is the foundation of understanding gene annotation, expression, and function.
Common features
The structures of both eukaryotic and prokaryotic genes involve several nested sequence elements. Each element has a specific function in the multi-step process of gene expression. The sequences and lengths of these elements vary, but the same general functions are present in most genes. Although DNA is a double-stranded molecule, typically only one of the strands encodes information that the RNA polymerase reads to produce protein-coding mRNA or non-coding RNA. This 'sense' or 'coding' strand, runs in the 5' to 3' direction where the numbers refer to the carbon atoms of the backbone's ribose sugar. The open reading frame (ORF) of a gene is therefore usually represente
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https://en.wikipedia.org/wiki/Pseudorandom%20permutation
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In cryptography, a pseudorandom permutation (PRP) is a function that cannot be distinguished from a random permutation (that is, a permutation selected at random with uniform probability, from the family of all permutations on the function's domain) with practical effort.
Definition
Let F be a mapping . F is a PRP if and only if
For any , is a bijection from to , where .
For any , there is an "efficient" algorithm to evaluate for any ,.
For all probabilistic polynomial-time distinguishers : , where is chosen uniformly at random and is chosen uniformly at random from the set of permutations on n-bit strings.
A pseudorandom permutation family is a collection of pseudorandom permutations, where a specific permutation may be chosen using a key.
The model of block ciphers
The idealized abstraction of a (keyed) block cipher is a truly random permutation on the mappings between plaintext and ciphertext. If a distinguishing algorithm exists that achieves significant advantage with less effort than specified by the block cipher's security parameter (this usually means the effort required should be about the same as a brute force search through the cipher's key space), then the cipher is considered broken at least in a certificational sense, even if such a break doesn't immediately lead to a practical security failure.
Modern ciphers are expected to have super pseudorandomness.
That is, the cipher should be indistinguishable from a randomly chosen permutation on the same message space, even if the adversary has black-box access to the forward and inverse directions of the cipher.
Connections with pseudorandom function
Michael Luby and Charles Rackoff showed that a "strong" pseudorandom permutation can be built from a pseudorandom function using a Luby–Rackoff construction which is built using a Feistel cipher.
Related concepts
Unpredictable permutation
An unpredictable permutation (UP) Fk is a permutation whose values cannot be predicted by a fast randomized
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https://en.wikipedia.org/wiki/Computational%20chemical%20methods%20in%20solid-state%20physics
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Computational chemical methods in solid-state physics follow the same approach as they do for molecules, but with two differences. First, the translational symmetry of the solid has to be utilised, and second, it is possible to use completely delocalised basis functions such as plane waves as an alternative to the molecular atom-centered basis functions. The electronic structure of a crystal is in general described by a band structure, which defines the energies of electron orbitals for each point in the Brillouin zone. Ab initio and semi-empirical calculations yield orbital energies, therefore they can be applied to band structure calculations. Since it is time-consuming to calculate the energy for a molecule, it is even more time-consuming to calculate them for the entire list of points in the Brillouin zone.
Calculations can use the Hartree–Fock method, some post-Hartree–Fock methods, particularly Møller–Plesset perturbation theory to second order (MP2) and density functional theory (DFT).
See also
List of quantum chemistry and solid-state physics software
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https://en.wikipedia.org/wiki/Directed%20evolution
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Directed evolution (DE) is a method used in protein engineering that mimics the process of natural selection to steer proteins or nucleic acids toward a user-defined goal. It consists of subjecting a gene to iterative rounds of mutagenesis (creating a library of variants), selection (expressing those variants and isolating members with the desired function) and amplification (generating a template for the next round). It can be performed in vivo (in living organisms), or in vitro (in cells or free in solution). Directed evolution is used both for protein engineering as an alternative to rationally designing modified proteins, as well as for experimental evolution studies of fundamental evolutionary principles in a controlled, laboratory environment.
History
Directed evolution has its origins in the 1960s with the evolution of RNA molecules in the "Spiegelman's Monster" experiment. The concept was extended to protein evolution via evolution of bacteria under selection pressures that favoured the evolution of a single gene in its genome.
Early phage display techniques in the 1980s allowed targeting of mutations and selection to a single protein. This enabled selection of enhanced binding proteins, but was not yet compatible with selection for catalytic activity of enzymes. Methods to evolve enzymes were developed in the 1990s and brought the technique to a wider scientific audience. The field rapidly expanded with new methods for making libraries of gene variants and for screening their activity. The development of directed evolution methods was honored in 2018 with the awarding of the Nobel Prize in Chemistry to Frances Arnold for evolution of enzymes, and George Smith and Gregory Winter for phage display.
Principles
Directed evolution is a mimic of the natural evolution cycle in a laboratory setting. Evolution requires three things to happen: variation between replicators, that the variation causes fitness differences upon which selection acts, and that this v
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https://en.wikipedia.org/wiki/Tumor%20metabolome
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The study of the tumor metabolism, also known as tumor metabolome describes the different characteristic metabolic changes in tumor cells. The characteristic attributes of the tumor metabolome are high glycolytic enzyme activities, the expression of the pyruvate kinase isoenzyme type M2, increased channeling of glucose carbons into synthetic processes, such as nucleic acid, amino acid and phospholipid synthesis, a high rate of pyrimidine and purine de novo synthesis, a low ratio of Adenosine triphosphate and Guanosine triphosphate to Cytidine triphosphate and Uridine triphosphate, low Adenosine monophosphate levels, high glutaminolytic capacities, release of immunosuppressive substances and dependency on methionine.
Although the link between the cancer and metabolism was observed in the early days of cancer research by Otto Heinrich Warburg, which is also known as Warburg hypothesis, not much substantial research was carried out until the late 1990s because of the lack of in vitro tumor models and the difficulty in creating environments that lack oxygen. Recent research has revealed that metabolic reprogramming occurs as a consequence of mutations in cancer genes and alterations in cellular signaling. Therefore, the alteration of cellular and energy metabolism has been suggested as one of The Hallmarks of Cancer.
Warburg effect and glycolysis
High amount of aerobic glycolysis (also known as the Warburg effect) distinguishes cancer cells from normal cells. The conversion of glucose to lactate rather than metabolizing it in the mitochondria through oxidative phosphorylation, (which can also occur in hypoxic normal cells) persists in malignant tumor despite the presence of oxygen. This process normally inhibits glycolysis which is also known as Pasteur effect. One of the reasons it is observed is because of the malfunction of mitochondria. Although ATP production by glycolysis can be more rapid than by oxidative phosphorylation, it is far less efficient in terms of A
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https://en.wikipedia.org/wiki/Tak%20%28function%29
|
In computer science, the Tak function is a recursive function, named after Ikuo Takeuchi (:ja:竹内郁雄). It is defined as follows:
def tak(x, y, z):
if y < x:
return tak(
tak(x-1, y, z),
tak(y-1, z, x),
tak(z-1, x, y)
)
else:
return z
This function is often used as a benchmark for languages with optimization for recursion.
tak() vs. tarai()
The original definition by Takeuchi was as follows:
def tarai(x, y, z):
if y < x:
return tarai(
tarai(x-1, y, z),
tarai(y-1, z, x),
tarai(z-1, x, y)
)
else:
return y # not z!
tarai is short for たらい回し tarai mawashi, "to pass around" in Japanese.
John McCarthy named this function tak() after Takeuchi.
However, in certain later references, the y somehow got turned into the z. This is a small, but significant difference because the original version benefits significantly from lazy evaluation.
Though written in exactly the same manner as others, the Haskell code below runs much faster.
tarai :: Int -> Int -> Int -> Int
tarai x y z
| x <= y = y
| otherwise = tarai (tarai (x-1) y z)
(tarai (y-1) z x)
(tarai (z-1) x y)
One can easily accelerate this function via memoization yet lazy evaluation still wins.
The best known way to optimize tarai is to use mutually recursive helper function as follows.
def laziest_tarai(x, y, zx, zy, zz):
if not y < x:
return y
else:
return laziest_tarai(
tarai(x-1, y, z),
tarai(y-1, z, x),
tarai(zx, zy, zz)-1, x, y)
def tarai(x, y, z):
if not y < x:
return y
else:
return laziest_tarai(
tarai(x-1, y, z),
tarai(y-1, z, x),
z-1, x, y)
Here is an efficient implementation of tarai() in C:
int tarai(int x, int y, int z)
{
while (x > y) {
int oldx = x, oldy = y;
x = tarai(
|
https://en.wikipedia.org/wiki/Conformal%20coating
|
Conformal coating is a protective, breathable coating of thin polymeric film applied to printed circuit boards (PCBs). Conformal coatings are typically applied at 25–250 μm to the electronic circuitry and provide protection against moisture and other harsher conditions.
Coatings can be applied in a number of ways including brushing, spraying, dispensing, and dip coating. A number of materials can be used as conformal coatings, such as acrylics, silicones, urethanes and parylene. Each has its own characteristics, making them contain different characteristics for different manufacturing use cases. Many circuit board assembly firms can coat assemblies with a layer of transparent conformal coating, which is used as an alternative to potting.
Reasons for use
Conformal coatings are used to protect electronic components from the environmental factors they are exposed to. Examples of these factors include moisture, dust, salt, chemicals, temperature changes and mechanical abrasion, as well as corrosion. More recently, conformal coatings are being used to reduce the formation of whiskers, and can also prevent current bleed between closely positioned components.
Conformal coatings are breathable, allowing trapped moisture in electronic boards to escape while maintaining protection from contamination. These coatings are not sealants, and prolonged exposure to vapors will cause transmission and degradation to occur. There are typically four classes of conformal coatings: Acrylic, Urethane, Silicone, and Varnish. While each has its own specific physical and chemical properties each is able to perform the following functions:
Insulation: Allowing closer conductor spacing
Minimal effect on component weight
More board protection including that of environmental, chemical, and corrosive
Applications
Precision analog circuitry may suffer degraded accuracy if insulating surfaces become contaminated with ionic substances such as fingerprint residues, which can become mildly co
|
https://en.wikipedia.org/wiki/Tympanic%20nerve
|
The tympanic nerve (Jacobson’s nerve) is a branch of the glossopharyngeal nerve found near the ear. It gives sensation to the middle ear, the Eustachian tube, the parotid gland, and mastoid air cells. It gives parasympathetic to supply to the parotid gland via the otic ganglion and the auriculotemporal nerve.
Structure
The tympanic nerve contains sensory axons to the middle ear (including the internal surface of the tympanic membrane) whose cell bodies are lodged in the superior ganglion of the glossopharyngeal nerve.
It also contains parasympathetic axons which continue as the lesser petrosal nerve to the otic ganglion, which itself gives off postganglionic parasympathetic neurons.
Origin
The tympanic nerve arises from the inferior ganglion of the glossopharyngeal nerve (CN IX) in the jugular fossa.
Course
It passes through the petrous part of the temporal bone within the tympanic canaliculus that is situated within the bony ridge separating the carotid canal and the jugular foramen to reach the middle ear.
In the tympanic cavity of the middle ear, it ramifies upon the promontory of tympanic cavity to form the tympanic plexus.
Distribution
Sensory
The tympanic nerve provides sensation to the middle ear (tympanic cavity). This includes the internal surface of the tympanic membrane. It also supplies the Eustachian tube, the parotid gland, and mastoid air cells.
Parasympathetic autonomic
The tympanic nerve is also the parasympathetic root of the otic ganglion. These neurons then provide secretomotor innervation of the parotid gland via the auriculotemporal nerve. It is involved in the salivatory reflex to increase salivation during chewing.
Variation
The tympanic nerve usually arises from the inferior ganglion of the glossopharyngeal nerve. Rarely, it may arise from a higher part. Rarely, it may provide no parasympathetic fibres to the otic ganglion.
Clinical significance
The tympanic nerve is involved in a reflex, where stimulation of the ear canal i
|
https://en.wikipedia.org/wiki/Lesser%20petrosal%20nerve
|
The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) nerve conveying pre-ganglionic parasympathetic secretomotor fibers for the parotid gland from the tympanic plexus to the otic ganglion (where they synapse). It passes out of the tympanic cavity through the petrous part of the temporal bone into the middle cranial fossa of the cranial cavity, then exits the cranial cavity through its own canaliculus to reach the infratemporal fossa.
Cell bodies of the lesser petrosal nerve are situated in the inferior salivatory nucleus, and are conveyed first by the glossopharyngeal nerve (CN IX) and then by the tympanic nerve to the tympanic plexus.
Structure
Course
The nucleus of the lesser petrosal nerve is the inferior salivatory nucleus. The lesser petrosal nerve may be considered a continuation of the tympanic nerve.
After arising in the tympanic plexus, the lesser petrosal nerve passes anterior-ward, then through the hiatus for lesser petrosal nerve on the anterior surface of the petrous part of the temporal bone into the middle cranial fossa.
It runs across the floor of this fossa along a groove oriented in the direction the foramen ovale and situated parallel and anterolateral to the groove for the greater petrosal nerve and its groove.
It exits the skull via canaliculus innominatus and enters the infratemporal fossa. In the fossa, its fibres synapse at the otic ganglion. Post-ganglionic fibres then exit the ganglion to briefly travel along with the auriculotemporal nerve (a branch of the mandibular nerve (CN V3)) before entering the substance of the parotid gland.
The lesser petrosal nerve distributes its post-ganglionic parasympathetic (GVE) fibers to the parotid gland via the intraparotid plexus (or parotid plexus), the branches from the facial nerve in the parotid gland.
See also
Tympanic nerve
Glossopharyngeal Nerve, Overview of visceral motor component
|
https://en.wikipedia.org/wiki/Fatou%E2%80%93Bieberbach%20domain
|
In mathematics, a Fatou–Bieberbach domain is a proper subdomain of , biholomorphically equivalent to . That is, an open set is called a Fatou–Bieberbach domain if there exists a bijective holomorphic function whose inverse function is holomorphic. It is well-known that the inverse can not be polynomial.
History
As a consequence of the Riemann mapping theorem, there are no Fatou–Bieberbach domains in the case n = 1.
Pierre Fatou and Ludwig Bieberbach first explored such domains in higher dimensions in the 1920s, hence the name given to them later. Since the 1980s, Fatou–Bieberbach domains have again become the subject of mathematical research.
|
https://en.wikipedia.org/wiki/Method%20of%20images
|
The method of images (or method of mirror images) is a mathematical tool for solving differential equations, in which the domain of the sought function is extended by the addition of its mirror image with respect to a symmetry hyperplane. As a result, certain boundary conditions are satisfied automatically by the presence of a mirror image, greatly facilitating the solution of the original problem. The domain of the function is not extended. The function is made to satisfy given boundary conditions by placing singularities outside the domain of the function. The original singularities are inside the domain of interest. The additional (fictitious) singularities are an artifact needed to satisfy the prescribed but yet unsatisfied boundary conditions.
Method of image charges
The method of image charges is used in electrostatics to simply calculate or visualize the distribution of the electric field of a charge in the vicinity of a conducting surface. It is based on the fact that the tangential component of the electrical field on the surface of a conductor is zero, and that an electric field E in some region is uniquely defined by its normal component over the surface that confines this region (the uniqueness theorem).
Magnet-superconductor systems
The method of images may also be used in magnetostatics for calculating the magnetic field of a magnet that is close to a superconducting surface. The superconductor in so-called Meissner state is an ideal diamagnet into which the magnetic field does not penetrate. Therefore, the normal component of the magnetic field on its surface should be zero. Then the image of the magnet should be mirrored. The force between the magnet and the superconducting surface is therefore repulsive.
Comparing to the case of the charge dipole above a flat conducting surface, the mirrored magnetization vector can be thought as due to an additional sign change of an axial vector.
In order to take into account the magnetic flux pinning p
|
https://en.wikipedia.org/wiki/Posterior%20meningeal%20artery
|
The posterior meningeal artery is one of the meningeal branches of the ascending pharyngeal artery (and is typically considered the terminal branch of said artery). It passes through the jugular foramen to enter the posterior cranial fossa. It is the largest vessel supplying the dura of the posterior cranial fossa.
It may occasionally arise from other arteries (e.g. the occipital artery).
It forms anastomoses with the branches of the middle meningeal artery, and the vertebral artery.
|
https://en.wikipedia.org/wiki/Posterior%20ethmoidal%20artery
|
The posterior ethmoidal artery is an artery of the head which arises from the ophthalmic artery to supply the posterior ethmoidal air cells, and the meninges. It is smaller than the anterior ethmoidal artery.
Anatomy
Origin
The posterior ethmoidal artery is an orbital branch of the ophthalmic artery.
Course and relations
After branching from the ophthalmic artery, the posterior ethmoidal artery passes between the upper border of the medial rectus muscle and superior oblique muscle to reach, enter and traverse the posterior ethmoidal canal.
Branches
Meningeal branch
It emits a meningeal branch to the dura mater after entering the cranium.
Nasal branches
It emits nasal branches that pass through the cribriform plate to reach the nasal cavity. The nasal branches form anastomoses with the sphenopalatine artery.
Distribution
This artery supplies the posterior ethmoidal air sinuses, the dura mater of the anterior cranial fossa, and the upper part of the nasal mucosa of the nasal septum.
|
https://en.wikipedia.org/wiki/Fault%20%28technology%29
|
In document ISO 10303-226, a fault is defined as an abnormal condition or defect at the component, equipment, or sub-system level which may lead to a failure.
In telecommunications, according to the Federal Standard 1037C of the United States, the term fault has the following meanings:
An accidental condition that causes a functional unit to fail to perform its required function. See .
A defect that causes a reproducible or catastrophic malfunction. A malfunction is considered reproducible if it occurs consistently under the same circumstances. See .
In power systems, an unintentional short circuit, or partial short circuit, between energized conductors or between an energized conductor and ground. A distinction can be made between symmetric and asymmetric faults. See Fault (power engineering).
Random fault
A random fault is a fault that occurs as a result of wear or other deterioration. Whereas the time of a particular occurrence of such a fault cannot be determined, the rate at which such faults occur within the equipment population on average can be predicted with accuracy. Manufacturers will often accept random faults as a risk if the chances are virtually negligible.
A fault can happen in virtually any object or appliance, most common with electronics and machinery.
For example, an Xbox 360 console will deteriorate over time due to dust buildup in the fans. This will cause the Xbox to overheat, cause an error, and shut the console down.
Systematic fault
Systematic faults are often a result of an error in the specification of the equipment and therefore affect all examples of that type. Such faults can remain undetected for years, until conditions conduce to create the failure. Given the same circumstances, each and every example of the equipment would fail identically at that time.
Failures in hardware can be caused by random faults or systematic faults, but failures in software are always systematic.
See also
Product defect
Reliability engineering
|
https://en.wikipedia.org/wiki/Great%20blue%20turaco
|
The great blue turaco (Corythaeola cristata) is a bird species of the family Musophagidae. At in length, it is the largest species of turaco. It has predominantly grey-blue plumage with an upright blue-black crest around high. The male and female have similar plumage. It is widespread throughout the African tropical rainforest.
Taxonomy
French ornithologist Louis Vieillot described the great blue turaco as Musophaga cristata in 1816, before German ornithologist Ferdinand Heine placed it in its own genus in 1860.
The great blue turaco is the sole member of the subfamily Corythaeolinae within the turaco family. Its closest relatives are the go-away birds and plantain eaters of the genus Crinifer. The common ancestor of both diverged from the ancestor of all other turaco species.
"Great blue turaco" has been designated the official common name by the International Ornithologists' Union (IOC). It is also called blue plantain eater.
Description
Generally, the great blue turaco is in length with a mass of . The adult great blue turaco has predominantly gray-blue upperparts with an upright blue-black crest, white chin, yellow-green lower breast and yellow belly darkening to chestnut brown posteriorly. The undertail coverts are chestnut, and the undertail is black and yellowish. The yellow bill has an orange-red tip, the eyes are brown, and surrounded by a ring of black bare skin. The legs and feet are black with yellow soles. The sexes have similar plumage.
Distribution and habitat
The species ranges from Guinea in the west, east across the sub-Saharan nations to the Imatong Mountains in South Sudan; it also occurs in Uganda, Tanzania and western Kenya, south to the Democratic Republic of Congo and Angola. It inhabits rainforests and gallery forests. It has also adapted to areas cleared by humans and can thrive in these areas.
Behaviour
The great blue turaco is gregarious, with birds forming small troops of some six or seven individuals.
Feeding
The great blue t
|
https://en.wikipedia.org/wiki/Optical%20path
|
Optical path (OP) is the trajectory that a light ray follows as it propagates through an optical medium.
The geometrical optical-path length or simply geometrical path length (GPD) is the length of a segment in a given OP, i.e., the Euclidean distance integrated along a ray between any two points.
The mechanical length of an optical device can be reduced to less than the GPD by using folded optics.
The optical path length in a homogeneous medium is the GPD multiplied by the refractive index of the medium.
Factors affecting optical path
Path of light in medium, or between two media is affected by the following:
Reflection
Total internal reflection
Refraction
Dispersion of light
Absorption
Simple materials used
Lenses
Prisms
Mirrors
Transparent materials (e.g. optical filters)
Translucent materials (e.g. frosted glass)
Opaque materials
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https://en.wikipedia.org/wiki/Sphere%20theorem
|
In Riemannian geometry, the sphere theorem, also known as the quarter-pinched sphere theorem, strongly restricts the topology of manifolds admitting metrics with a particular curvature bound. The precise statement of the theorem is as follows. If M is a complete, simply-connected, n-dimensional Riemannian manifold with sectional curvature taking values in the interval then M is homeomorphic to the n-sphere. (To be precise, we mean the sectional curvature of every tangent 2-plane at each point must lie in .) Another way of stating the result is that if M is not homeomorphic to the sphere, then it is impossible to put a metric on M with quarter-pinched curvature.
Note that the conclusion is false if the sectional curvatures are allowed to take values in the closed interval . The standard counterexample is complex projective space with the Fubini–Study metric; sectional curvatures of this metric take on values between 1 and 4, with endpoints included. Other counterexamples may be found among the rank one symmetric spaces.
Differentiable sphere theorem
The original proof of the sphere theorem did not conclude that M was necessarily diffeomorphic to the n-sphere. This complication is because spheres in higher dimensions admit smooth structures that are not diffeomorphic. (For more information, see the article on exotic spheres.) However, in 2007 Simon Brendle and Richard Schoen utilized Ricci flow to prove that with the above hypotheses, M is necessarily diffeomorphic to the n-sphere with its standard smooth structure. Moreover, the proof of Brendle and Schoen only uses the weaker assumption of pointwise rather than global pinching. This result is known as the differentiable sphere theorem.
History of the sphere theorem
Heinz Hopf conjectured that a simply connected manifold with pinched sectional curvature is a sphere. In 1951, Harry Rauch showed that a simply connected manifold with curvature in [3/4,1] is homeomorphic to a sphere. In 1960, Marcel Berger a
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https://en.wikipedia.org/wiki/Against%20DRM%20license
|
Against DRM 2.0 is a free copyleft license for artworks. It is the first free content license that contains a clause about related rights and a clause against digital rights management (DRM).
The first clause authorizes the licensee to exercise related rights, while the second clause prevents the use of DRM. If the licensor uses DRM, the license is not applicable to the work; if the licensee uses DRM, license is automatically void.
According to Internet Archive, the first version of the Against DRM 2.0 license was published in 2006.
Notes
External links
Against DRM license version 2.0 on Internet Archive, archived on March 27th, 2017
Free Creations website on Internet Archive, archived on March 27th, 2017
The Readers' Bill of Rights for Digital Books
Digital rights management
Free content licenses
Business of visual arts
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https://en.wikipedia.org/wiki/Synchronization%20model
|
In configuration management (CM), one has to control (among other things) changes made to software and documentation. This is called revision control, which manages multiple versions of the same unit of information. Although revision control is important to CM, it is not equal to it.
Synchronization Models, also known as Configuration Management Models (Feiler, 1991), describe methods to enable revision control through allowing simultaneous, concurrent changes to individual files.
Synchronization models
Feiler (1991) reports on four different synchronization models, shortly described below.
Check-out/check-in
In the check-out/check-in model, files are stored individually in a repository from which they are checked out whenever the files are accessed, and checked in when they have changed. This repository can store multiple versions of the files. Because these files can be documentation or source code, but can also be a collection of files, the term Configuration item (CI) will be used from now on. The basic mechanism used to prevent conflicts by simultaneous modifications is that of locking.
Composition
The composition model is an extension on the check-out/check-in model. This model allows developers to think in configurations instead of individual files. Although the complete check-out/check-in model is represented in the composition model, it enables the use of different strategies for updating through the use of improved support for the management of configurations. A configuration is defined as being built up from a system model and version selection rules. The system model determines which files are used, while the version selection rules determine which version of the files (e.g. the latest versions or of a certain development state).
Long transactions
The long transactions model takes a broader approach by assuming that a system is built up out of logical changes. Its focus is on the coordination and integration of these changes. Basically, it uses
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https://en.wikipedia.org/wiki/183%20%28number%29
|
183 (one hundred [and] eighty-three) is the natural number following 182 and preceding 184.
In mathematics
183 is a perfect totient number, a number that is equal to the sum of its iterated totients
Because , it is the number of points in a projective plane over the finite field . 183 is the fourth element of a divisibility sequence in which the th number can be computed as
for a transcendental number . This sequence counts the number of trees of height in which each node can have at most two children.
There are 183 different semiorders on four labeled elements.
See also
The year AD 183 or 183 BC
List of highways numbered 183
|
https://en.wikipedia.org/wiki/Statistical%20field%20theory
|
In theoretical physics, statistical field theory (SFT) is a theoretical framework that describes phase transitions. It does not denote a single theory but encompasses many models, including for magnetism, superconductivity, superfluidity, topological phase transition, wetting as well as non-equilibrium phase transitions. A SFT is any model in statistical mechanics where the degrees of freedom comprise a field or fields. In other words, the microstates of the system are expressed through field configurations. It is closely related to quantum field theory, which describes the quantum mechanics of fields, and shares with it many techniques, such as the path integral formulation and renormalization.
If the system involves polymers, it is also known as polymer field theory.
In fact, by performing a Wick rotation from Minkowski space to Euclidean space, many results of statistical field theory can be applied directly to its quantum equivalent. The correlation functions of a statistical field theory are called Schwinger functions, and their properties are described by the Osterwalder–Schrader axioms.
Statistical field theories are widely used to describe systems in polymer physics or biophysics, such as polymer films, nanostructured block copolymers or polyelectrolytes.
Notes
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https://en.wikipedia.org/wiki/TIM-011
|
TIM 011 is an educational or personal computer for school microcomputer developed by Mihajlo Pupin Institute of Serbia in 1987. There were about 1200 TIM-011 computers in Serbian schools in the starting from 1987 and in 1990s.
It were based on CP/M with Hitachi HD64180, Z80A enhanced CPU with MMU , 256KB RAM standard, 3.5" floppy drives and integrated 512 X 256 green-screen monitors with 4 levels of intensity.
Reference literature
Dragoljub Milićević, Dušan Hristović (Ed): "Računari TIM" (TIM Computers), Naučna knjiga, Belgrade 1990.
D.B.Vujaklija, N.Markovic (Ed): "50 Years of Computing in Serbia (50 godina računarstva u Srbiji- Hronika digitalnih decenija)", DIS, IMP and PC-Press, Belgrade 2011.
|
https://en.wikipedia.org/wiki/List%20of%20types%20of%20interferometers
|
An interferometer is a device for extracting information from the superposition of multiple waves.
Field and linear interferometers
Air-wedge shearing interferometer
Astronomical interferometer / Michelson stellar interferometer
Classical interference microscopy
Bath interferometer (common path)
Cyclic interferometer
Diffraction-grating interferometer (white light)
Double-slit interferometer
Dual-polarization interferometry
Fabry–Pérot interferometer
Fizeau interferometer
Fourier-transform interferometer
Fresnel interferometer (e.g. Fresnel biprism, Fresnel mirror or Lloyd's mirror)
Fringes of Equal Chromatic Order interferometer (FECO)
Gabor hologram
Gires–Tournois etalon
Heterodyne interferometer (see heterodyne)
Holographic interferometer
Jamin interferometer
Laser Doppler vibrometer
Linnik interferometer (microscopy)
LUPI variant of Michelson
Lummer–Gehrcke interferometer
Mach–Zehnder interferometer
Martin–Puplett interferometer
Michelson interferometer
Mirau interferometer (also known as a Mirau objective) (microscopy)
Moiré interferometer (see moiré pattern)
Multi-beam interferometer (microscopy)
Near-field interferometer
Newton interferometer (see Newton's rings)
Nomarski interferometer
Nonlinear Michelson interferometer / Step-phase Michelson interferometer
N-slit interferometer
Phase-shifting interferometer
Planar lightwave circuit interferometer (PLC)
Photon Doppler velocimeter interferometer (PDV)
Polarization interferometer (see also Babinet–Soleil compensator)
Point diffraction interferometer
Rayleigh interferometer
Sagnac interferometer
Schlieren interferometer (phase-shifting)
Shearing interferometer (lateral and radial)
Twyman–Green interferometer
Talbot–Lau interferometer
Watson interferometer (microscopy)
White-light interferometer (see also Optical coherence tomography, White light interferometry, and Coherence Scanning Interferometry)
White-light scatterplate interferometer (white-light) (microscopy)
Young's double-slit interferometer
Zernik
|
https://en.wikipedia.org/wiki/Soil%20biology
|
Soil biology is the study of microbial and faunal activity and ecology in soil.
Soil life, soil biota, soil fauna, or edaphon is a collective term that encompasses all organisms that spend a significant portion of their life cycle within a soil profile, or at the soil-litter interface.
These organisms include earthworms, nematodes, protozoa, fungi, bacteria, different arthropods, as well as some reptiles (such as snakes), and species of burrowing mammals like gophers, moles and prairie dogs. Soil biology plays a vital role in determining many soil characteristics. The decomposition of organic matter by soil organisms has an immense influence on soil fertility, plant growth, soil structure, and carbon storage. As a relatively new science, much remains unknown about soil biology and its effect on soil ecosystems.
Overview
The soil is home to a large proportion of the world's biodiversity. The links between soil organisms and soil functions are complex. The interconnectedness and complexity of this soil ‘food web’ means any appraisal of soil function must necessarily take into account interactions with the living communities that exist within the soil. We know that soil organisms break down organic matter, making nutrients available for uptake by plants and other organisms. The nutrients stored in the bodies of soil organisms prevent nutrient loss by leaching. Microbial exudates act to maintain soil structure, and earthworms are important in bioturbation. However, we find that we don't understand critical aspects about how these populations function and interact. The discovery of glomalin in 1995 indicates that we lack the knowledge to correctly answer some of the most basic questions about the biogeochemical cycle in soils. There is much work ahead to gain a better understanding of the ecological role of soil biological components in the biosphere.
In balanced soil, plants grow in an active and steady environment. The mineral content of the soil and its heartiful
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https://en.wikipedia.org/wiki/European%20Home%20Systems%20Protocol
|
European Home Systems (EHS) Protocol was a communication protocol aimed at home appliances control and communication using power line communication (PLC), developed by the European Home Systems Association (EHSA).
After merging with two other protocols, it is a part of the KNX standard, which complies with the European Committee for Electrotechnical Standardization (CENELEC) norm EN 50090 and has a chance to be a basis for the first open standard for home and building control.
See also
Building automation
Home automation
External links
Home Automation with EHS: Cheap But Slow - Nikkei Electronics Asia
www.cenelec.eu - European Committee for Electrotechnical Standardization
www.konnex.org - association aimed at development of home and building control systems.
Home automation
Network protocols
|
https://en.wikipedia.org/wiki/Serpentine%20shape
|
A serpentine shape is any of certain curved shapes of an object or design, which are suggestive of the shape of a snake (the adjective "serpentine" is derived from the word serpent). Serpentine shapes occur in architecture, in furniture, and in mathematics.
In architecture and urban design
The serpentine shape is observed in many architectural settings. It may provide strength, as in serpentine walls, it may allow the facade of a building to face in multiple directions, or it may be chosen for purely aesthetic reasons.
At the University of Virginia, serpentine walls (crinkle crankle walls) extend down the length of the main lawn at the University of Virginia and flank both sides of the rotunda. They are one of the many structures Thomas Jefferson created that combine aesthetics with utility. The sinusoidal path of the wall provides strength against toppling over, allowing the wall to be only a single brick thick.
At the Massachusetts Institute of Technology, the Baker House dormitory has a serpentine shape which allows most rooms a view of the Charles River, and gives many of the rooms a wedge-shaped layout.
At San Carlo alle Quattro Fontane, Rome, Italy (The Church of Saint Charles at the Four Fountains), designed by Francesco Borromini, is a serpentine facade constructed towards the end of Borromini's life. The concave-convex facade of the church undulates in a non-classic way. Tall Corinthian columns stand on plinths and support the main entablatures; these define the main framework of two stories and the tripartite bay division. Between the columns, smaller columns with their entablatures weave behind the main columns and in turn they frame many architectural features of the church.
The London parks Hyde Park and Kensington Gardens contain 'The Serpentine', a lake that spans both parks. It received the name from its snake-like, curving shape. A central bridge divides the lake into two parts and defines the boundaries between Hyde Park and Kensington Gardens.
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https://en.wikipedia.org/wiki/Kingston%20Technology
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Kingston Technology Corporation is an American multinational computer technology corporation that develops, manufactures, sells and supports flash memory products, other computer-related memory products, as well as the HyperX gaming division (now owned by HP). Headquartered in Fountain Valley, California, United States, Kingston Technology employs more than 3,000 employees worldwide as of Q1 2016. The company has manufacturing and logistics facilities in the United States, United Kingdom, Ireland, Taiwan, and China.
It is the largest independent producer of DRAM memory modules, owning approximately 68% of the third-party worldwide DRAM module market share in 2017, according to DRAMeXchange. In 2018 the company generated $7.5 billion in revenue and made #53 on the Forbes Lists of "America's Largest Private Companies 2019." Kingston serves an international network of distributors, resellers, retailers and OEM customers on six continents. The company also provides contract manufacturing and supply chain management services for semiconductor manufacturers and system OEMs.
History
Kingston Technology was founded on October 17, 1987, in response to a severe shortage of 1Mbit surface-mount memory chips, Chinese immigrant John Tu designed a new single in-line memory module (SIMM) that used readily available, older-technology through-hole components. In 1990 the company branched out into its first non-memory product line, processor upgrades. By 1992, the firm was ranked #1 by Inc. as the fastest-growing privately held company in America. The company expanded into networking and storage product lines, and introduced DataTraveler and DataPak portable products. In September 1994, Kingston became ISO 9000 certified on its first assessment attempt.
In 1995, Kingston opened a branch office in Munich, Germany to provide technical support and marketing capabilities for its European distributors and customers.
In October 1995, the company joined the "Billion-Dollar Club". After
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https://en.wikipedia.org/wiki/Reinhardt%20cardinal
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In set theory, a branch of mathematics, a Reinhardt cardinal is a kind of large cardinal. Reinhardt cardinals are considered under ZF (Zermelo–Fraenkel set theory without the Axiom of Choice), because they are inconsistent with ZFC (ZF with the Axiom of Choice). They were suggested by American mathematician William Nelson Reinhardt (1939–1998).
Definition
A Reinhardt cardinal is the critical point of a non-trivial elementary embedding of into itself.
This definition refers explicitly to the proper class . In standard ZF, classes are of the form for some set and formula . But it was shown in
that no such class is an elementary embedding . So Reinhardt cardinals are inconsistent with this notion of class.
There are other formulations of Reinhardt cardinals which are not known to be inconsistent. One is to add a new function symbol to the language of ZF, together with axioms stating that is an elementary embedding of , and Separation and Collection axioms for all formulas involving . Another is to use a class theory such as NBG or KM, which admit classes which need not be definable in the sense above.
Kunen's inconsistency theorem
proved his inconsistency theorem, showing that the existence of an elementary embedding contradicts NBG with the axiom of choice (and ZFC extended by ). His proof uses the axiom of choice, and it is still an open question as to whether such an embedding is consistent with NBG without the axiom of choice (or with ZF plus the extra symbol and its attendant axioms).
Kunen's theorem is not simply a consequence of ,
as it is a consequence of NBG, and hence does not require the assumption that is a definable class.
Also, assuming exists, then there is an elementary embedding of a transitive model of ZFC (in fact Goedel's constructible universe ) into itself. But such embeddings are not classes of .
Stronger axioms
There are some variations of Reinhardt cardinals, forming a hierarchy of hypotheses asserting the existence
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https://en.wikipedia.org/wiki/Block%20matrix%20pseudoinverse
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In mathematics, a block matrix pseudoinverse is a formula for the pseudoinverse of a partitioned matrix. This is useful for decomposing or approximating many algorithms updating parameters in signal processing, which are based on the least squares method.
Derivation
Consider a column-wise partitioned matrix:
If the above matrix is full column rank, the Moore–Penrose inverse matrices of it and its transpose are
This computation of the pseudoinverse requires (n + p)-square matrix inversion and does not take advantage of the block form.
To reduce computational costs to n- and p-square matrix inversions and to introduce parallelism, treating the blocks separately, one derives
where orthogonal projection matrices are defined by
The above formulas are not necessarily valid if does not have full rank – for example, if , then
Application to least squares problems
Given the same matrices as above, we consider the following least squares problems, which
appear as multiple objective optimizations or constrained problems in signal processing.
Eventually, we can implement a parallel algorithm for least squares based on the following results.
Column-wise partitioning in over-determined least squares
Suppose a solution solves an over-determined system:
Using the block matrix pseudoinverse, we have
Therefore, we have a decomposed solution:
Row-wise partitioning in under-determined least squares
Suppose a solution solves an under-determined system:
The minimum-norm solution is given by
Using the block matrix pseudoinverse, we have
Comments on matrix inversion
Instead of , we need to calculate directly or indirectly
In a dense and small system, we can use singular value decomposition, QR decomposition, or Cholesky decomposition to replace the matrix inversions with numerical routines. In a large system, we may employ iterative methods such as Krylov subspace methods.
Considering parallel algorithms, we can compute and in parallel. Then, we finish to com
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https://en.wikipedia.org/wiki/Bragg%E2%80%93Gray%20cavity%20theory
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Bragg-Gray cavity theory relates the radiation dose in a cavity volume of material to the dose that would exist in a surrounding medium in the absence of the cavity volume. It was developed in 1936 by British scientists Louis Harold Gray, William Henry Bragg, and William Lawrence Bragg.
Most often, material is assumed to be a gas, however Bragg-Gray cavity theory applies to any cavity volume (gas, liquid, or solid) that meets the following Bragg-Gray conditions.
The dimensions of the cavity containing is small with respect to the range of charged particles striking the cavity so that the cavity does not perturb the charged particle field. That is, the cavity does not change the number, energy, or direction of the charged particles that would exist in in the absence of the cavity.
The absorbed dose in the cavity containing is deposited entirely by charged particles crossing it.
When the Bragg-Gray conditions are met, then
,
where
is the dose to material (SI unit Gray)
is the dose to the cavity material (SI unit Gray)
is the ratio of the mass-electronic stopping powers (also known as mass-collision stopping powers) of and averaged over the charged particle fluence crossing the cavity.
In an ionization chamber, the dose to material (typically a gas) is
where
is the ionization per unit volume produced in the (SI unit Coulomb)
is the mass of the gas (SI unit kg)
is the mean energy required to produce an ion pair in divided by the charge of an electron (SI units Joules/Coulomb)
See also
Ionizing radiation
Ionization chamber
Sources
Khan, F. M. (2003). The physics of radiation therapy (3rd ed.). Lippincott Williams & Wilkins: Philadelphia. .
Attix, F.H. (1986). Introduction to Radiological Physics and Radiation Dosimetry, Wiley-Interscience: New York. .
Physics theorems
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https://en.wikipedia.org/wiki/The%20Book%20of%20Squares
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The Book of Squares, (Liber Quadratorum in the original Latin) is a book on algebra by Leonardo Fibonacci, published in 1225. It was dedicated to Frederick II, Holy Roman Emperor.
The Liber quadratorum has been passed down by a single 15th-century manuscript, the so-called ms. E 75 Sup. of the Biblioteca Ambrosiana (Milan, Italy), ff. 19r-39v. During the 19th century, the work has been published for the first time in a printed edition by Baldassarre Boncompagni Ludovisi, prince of Piombino.
Appearing in the book is Fibonacci's identity, establishing that the set of all sums of two squares is closed under multiplication. The book anticipated the works of later mathematicians such as Fermat and Euler. The book examines several topics in number theory, among them an inductive method for finding Pythagorean triples based on the sequence of odd integers, the fact that the sum of the first odd integers is , and the solution to the congruum problem.
Notes
Further reading
B. Boncompagni Ludovisi, Opuscoli di Leonardo Pisano secondo un codice della Biblioteca Ambrosiana di Milano contrassegnato E.75. Parte Superiore, in Id., Scritti di Leonardo Pisano matematico del secolo decimoterzo, vol. II, Roma 1862, pp. 253–283
P. Ver Eecke, Léonard de Pise. Le livre des nombres carrés. Traduit pour la première fois du Latin Médiéval en Français, Paris, Blanchard-Desclée - Bruges 1952.
G. Arrighi, La fortuna di Leonardo Pisano alla corte di Federico II, in Dante e la cultura sveva. Atti del Convegno di Studi, Melfi, 2-5 novembre 1969, Firenze 1970, pp. 17–31.
E. Picutti, Il Libro dei quadrati di Leonardo Pisano e i problemi di analisi indeterminata nel Codice Palatino 557 della Biblioteca Nazionale di Firenze, in «Physis. Rivista Internazionale di Storia della Scienza» XXI, 1979, pp. 195–339.
L.E. Sigler, Leonardo Pisano Fibonacci, the book of squares. An annotated translation into modern English, Boston 1987.
M. Moyon, Algèbre & Practica geometriæ en Occident médiéval latin
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https://en.wikipedia.org/wiki/Mikl%C3%B3s%20Schweitzer%20Competition
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The Miklós Schweitzer Competition (Schweitzer Miklós Matematikai Emlékverseny in Hungarian) is an annual Hungarian mathematics competition for university undergraduates, established in 1949.
It is named after Miklós Schweitzer (1 February 1923 – 28 January 1945), a young Hungarian mathematician who died under the Siege of Budapest in the Second World War.
The Schweitzer contest is uniquely high-level among mathematics competitions. The problems, written by prominent Hungarian mathematicians, are challenging and require in-depth knowledge of the fields represented. The competition is open-book and competitors are allowed ten days to come up with solutions.
The problems on the competition can be classified roughly in the following categories:
1. Algebra
2. Combinatorics
3. Theory of Functions
4. Geometry
5. Measure Theory
6. Number Theory
7. Operators
8. Probability Theory
9. Sequences and Series
10. Topology
11. Set Theory
Recently a similar competition has been started in France.
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https://en.wikipedia.org/wiki/Affine%20curvature
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Special affine curvature, also known as the equiaffine curvature or affine curvature, is a particular type of curvature that is defined on a plane curve that remains unchanged under a special affine transformation (an affine transformation that preserves area). The curves of constant equiaffine curvature are precisely all non-singular plane conics. Those with are ellipses, those with are parabolae, and those with are hyperbolae.
The usual Euclidean curvature of a curve at a point is the curvature of its osculating circle, the unique circle making second order contact (having three point contact) with the curve at the point. In the same way, the special affine curvature of a curve at a point is the special affine curvature of its hyperosculating conic, which is the unique conic making fourth order contact (having five point contact) with the curve at . In other words, it is the limiting position of the (unique) conic through and four points on the curve, as each of the points approaches :
In some contexts, the affine curvature refers to a differential invariant of the general affine group, which may readily obtained from the special affine curvature by , where is the special affine arc length. Where the general affine group is not used, the special affine curvature is sometimes also called the affine curvature.
Formal definition
Special affine arclength
To define the special affine curvature, it is necessary first to define the special affine arclength (also called the equiaffine arclength). Consider an affine plane curve . Choose coordinates for the affine plane such that the area of the parallelogram spanned by two vectors and is given by the determinant
In particular, the determinant
is a well-defined invariant of the special affine group, and gives the signed area of the parallelogram spanned by the velocity and acceleration of the curve . Consider a reparameterization of the curve , say with a new parameter related to by means of a reg
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https://en.wikipedia.org/wiki/High%20dynamic%20range
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High dynamic range (HDR), also known as wide dynamic range, extended dynamic range, or expanded dynamic range, is a dynamic range higher than usual.
The term is often used in discussing the dynamic range of various signals such as images, videos, audio or radio. It may apply to the means of recording, processing, and reproducing such signals including analog and digitized signals.
The term is also the name of some of the technologies or techniques allowing to achieve high dynamic range images, videos, or audio.
Imaging
In this context, the term high dynamic range means there is a lot of variation in light levels within a scene or an image. The dynamic range refers to the range of luminosity between the brightest area and the darkest area of that scene or image.
(HDRI) refers to the set of imaging technologies and techniques that allow to increase the dynamic range of images or videos. It covers the acquisition, creation, storage, distribution and display of images and videos.
Modern movies have often been filmed with cameras featuring a higher dynamic range, and legacy movies can be converted even if manual intervention would be needed for some frames (as when black-and-white films are converted to color). Also, special effects, especially those that mix real and synthetic footage, require both HDR shooting and rendering. HDR video is also needed in applications that demand high accuracy for capturing temporal aspects of changes in the scene. This is important in monitoring of some industrial processes such as welding, in predictive driver assistance systems in automotive industry, in surveillance video systems, and other applications.
Capture
In photography and videography, a technique, commonly named high dynamic range (HDR), allows to increase the dynamic range of captured photos and videos beyond the native capability of the camera. It consists of capturing multiple frames of the same scene but with different exposures and then combining them into one
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https://en.wikipedia.org/wiki/Scram%20%28video%20game%29
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Scram: A Nuclear Power Plant Simulation is an Atari 8-bit family game written by Chris Crawford and published by Atari, Inc. in 1981. Written in Atari BASIC, Scram uses differential equations to simulate nuclear reactor behavior. The player controls the valves and switches of the reactor directly with the joystick.
This game's title, "SCRAM", is taken from the term for an emergency shutdown of a nuclear reactor. It refers to immediately inserting all control rods into the reactor core to stop the reaction process. The game also recreates the Three Mile Island Unit 2 nuclear reactor and allowed players to recreate the events that took place there in 1979.
Gameplay
The game display shows a schematic-like representation of a light water reactor, typical of nuclear reactors in use in the United States at that time. The reactor core is on the left of the screen, with the primary coolant loop to its immediate right. Further right is the secondary cooling loop, and finally the tertiary cooling loop and its associated cooling tower.
The user interacts with the game by moving the joystick, which makes a cursor jump from one "hot spot" to another on the screen, each one controlling one part of the reactor systems. There are hot spots for the control rods, cooling pumps and valves. The user can experiment with the reactor systems by moving the joystick up and down, operating the equipment. It is possible to simulate a meltdown by shutting off the primary cooling pumps and withdrawing the control rods all the way.
The game has several skill levels, which control the frequency of earthquakes and the obviousness of the damage. In the event of an earthquake the screen shakes, and a breaking sound is heard if there is damage. The user then has to watch the on-screen displays to try to isolate where the problem is.
Reception
One big fan of Scram was Harold Denton, the Director of the Office of Nuclear Reactor Regulation at the Nuclear Regulatory Commission. In an interview wit
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https://en.wikipedia.org/wiki/Valve%20audio%20amplifier
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A valve audio amplifier (UK) or vacuum tube audio amplifier (US) is a valve amplifier used for sound reinforcement, sound recording and reproduction.
Until the invention of solid state devices such as the transistor, all electronic amplification was produced by valve (tube) amplifiers. While solid-state devices prevail in most audio amplifiers today, valve audio amplifiers are still used where their audible characteristics are considered pleasing, for example in music performance or music reproduction.
Instrument and vocal amplification
Valve amplifiers for guitars (and to a lesser degree vocals and other applications) have different purposes from those of hi-fi amplifiers. The purpose is not necessarily to reproduce sound as accurately as possible, but rather to fulfill the musician's concept of what the sound should be. For example, distortion is almost universally considered undesirable in hi-fi amplifiers but may be considered a desirable characteristic in performance.
Small signal circuits are often deliberately designed to have very high gain, driving the signal far outside the linear range of the tube circuit, to deliberately generate large amounts of harmonic distortion. The distortion and overdrive characteristics of valves are quite different from transistors (not least the amount of voltage headroom available in a typical circuit) and this results in a distinctive sound. Amplifiers for such performance applications typically retain tone and filter circuits that have largely disappeared from modern hi-fi products. Amplifiers for guitars in particular may also include a number of "effects" functions.
Origins of electric guitar amplification
The electric guitar originates from Rickenbacker in the 1930s but its modern form was popularised by Fender and Gibson (notably the Fender Telecaster (1951) & Stratocaster (1954) and Gibson Les Paul (1952) during the 1950s. The earliest guitar amplifiers were probably audio amplifiers made for other purposes and pres
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https://en.wikipedia.org/wiki/TNT%20equivalent
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TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by convention to be (), which is the approximate energy released in the detonation of a metric ton (1,000 kilograms) of TNT. In other words, for each gram of TNT exploded, (or 4,184 joules) of energy are released.
This convention intends to compare the destructiveness of an event with that of conventional explosive materials, of which TNT is a typical example, although other conventional explosives such as dynamite contain more energy.
Kiloton and megaton
The "kiloton (of TNT equivalent)" is a unit of energy equal to 4.184 terajoules ().
The "megaton (of TNT equivalent)" is a unit of energy equal to 4.184 petajoules ().
The kiloton and megaton of TNT equivalent have traditionally been used to describe the energy output, and hence the destructive power, of a nuclear weapon. The TNT equivalent appears in various nuclear weapon control treaties, and has been used to characterize the energy released in asteroid impacts.
Historical derivation of the value
Alternative values for TNT equivalency can be calculated according to which property is being compared and when in the two detonation processes the values are measured.
Where for example the comparison is by energy yield, an explosive's energy is normally expressed for chemical purposes as the thermodynamic work produced by its detonation. For TNT this has been accurately measured as 4,686 J/g from a large sample of air blast experiments, and theoretically calculated to be 4,853 J/g.
However even on this basis, comparing the actual energy yields of a large nuclear device and an explosion of TNT can be slightly inaccurate. Small TNT explosions, especially in the open, don't tend to burn the carbon-particle and hydrocarbon products of the explosion. Gas-expansion and pressure-change effects tend to "freeze" the burn rapidly. A large open explosion of TNT may mai
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https://en.wikipedia.org/wiki/Database%20security
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Database security concerns the use of a broad range of information security controls to protect databases (potentially including the data, the database applications or stored functions, the database systems, the database servers and the associated network links) against compromises of their confidentiality, integrity and availability. It involves various types or categories of controls, such as technical, procedural/administrative and physical.
Security risks to database systems include, for example:
Unauthorized or unintended activity or misuse by authorized database users, database administrators, or network/systems managers, or by unauthorized users or hackers (e.g. inappropriate access to sensitive data, metadata or functions within databases, or inappropriate changes to the database programs, structures or security configurations);
Malware infections causing incidents such as unauthorized access, leakage or disclosure of personal or proprietary data, deletion of or damage to the data or programs, interruption or denial of authorized access to the database, attacks on other systems and the unanticipated failure of database services;
Overloads, performance constraints and capacity issues resulting in the inability of authorized users to use databases as intended;
Physical damage to database servers caused by computer room fires or floods, overheating, lightning, accidental liquid spills, static discharge, electronic breakdowns/equipment failures and obsolescence;
Design flaws and programming bugs in databases and the associated programs and systems, creating various security vulnerabilities (e.g. unauthorized privilege escalation), data loss/corruption, performance degradation etc.;
Data corruption and/or loss caused by the entry of invalid data or commands, mistakes in database or system administration processes, sabotage/criminal damage etc.
Ross J. Anderson has often said that by their nature large databases will never be free of abuse by breaches of
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https://en.wikipedia.org/wiki/Limit%20switch
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In electrical engineering, a limit switch is a switch operated by the motion of a machine part or the presence of an object. A limit switch can be used for controlling machinery as part of a control system, as a safety interlock, or as a counter enumerating objects passing a point.
Limit switches are used in a variety of applications and environments because of their ruggedness, ease of installation, and reliability of operation. They can determine the presence, passing, positioning, and end of travel of an object. They were first used to define the limit of travel of an object, hence the name "limit switch".
Standardized limit switches are industrial control components manufactured with a variety of operator types, including lever, roller plunger, and whisker type. Limit switches may be directly mechanically operated by the motion of the operating lever. A reed switch may be used to indicate proximity of a magnet mounted on some moving part. Proximity switches operate by the disturbance of an electromagnetic field, by capacitance, or by sensing a magnetic field.
Rarely, a final operating device such as a lamp or solenoid valve is directly controlled by the contacts of an industrial limit switch, but more typically the limit switch is wired through a control relay, a motor contactor control circuit, or as an input to a programmable logic controller.
Examples
Miniature snap-action switches are components of devices like photocopiers, computer printers, convertible tops or microwave ovens to ensure internal components are in the correct position for operation and to prevent operation when access doors are opened. A set of adjustable limit switches installed on a garage door opener shut off the motor when the door has reached the fully raised or fully lowered position. A numerical control machine such as a lathe has limit switches to identify maximum limits for machine parts or to provide a known reference point for incremental motions.
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https://en.wikipedia.org/wiki/And-inverter%20graph
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An and-inverter graph (AIG) is a directed, acyclic graph that represents a structural implementation of the logical functionality of a circuit or network. An AIG consists of two-input nodes representing logical conjunction, terminal nodes labeled with variable names, and edges optionally containing markers indicating logical negation. This representation of a logic function is rarely structurally efficient for large circuits, but is an efficient representation for manipulation of boolean functions. Typically, the abstract graph is represented as a data structure in software.
Conversion from the network of logic gates to AIGs is fast and scalable. It only requires that every gate be expressed in terms of AND gates and inverters. This conversion does not lead to unpredictable increase in memory use and runtime. This makes the AIG an efficient representation in comparison with either the binary decision diagram (BDD) or the "sum-of-product" (ΣoΠ) form, that is, the canonical form in Boolean algebra known as the disjunctive normal form (DNF). The BDD and DNF may also be viewed as circuits, but they involve formal constraints that deprive them of scalability. For example, ΣoΠs are circuits with at most two levels while BDDs are canonical, that is, they require that input variables be evaluated in the same order on all paths.
Circuits composed of simple gates, including AIGs, are an "ancient" research topic. The interest in AIGs started with Alan Turing's seminal 1948 paper on neural networks, in which he described a randomized trainable network of NAND gates. Interest continued through the late 1950s and continued in the 1970s when various local transformations have been developed. These transformations were implemented in several
logic synthesis and verification systems, such as Darringer et al. and Smith et al., which reduce circuits to improve area and delay during synthesis, or to speed up formal equivalence checking. Several important techniques were discov
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https://en.wikipedia.org/wiki/Merozygote
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Merozygote is a state when a cell, usually bacterial, is temporarily partial diploid as result of DNA transfer processes like conjugation.
One example of how merozygotes can be formed is the transfer of genetic material
of an Hfr cell to an F- cell through conjugation. When an Hfr cell mates with an F- cell, the chromosome acts as a rolling circle transferring a part of its genomic chromosome across a conjugation bridge. The origin is the first bit of the DNA to be injected, while the F-factor is the last. Very rarely the whole portion of the DNA (from the origin through the F-factor) will be transferred, resulting in a very low chance of passing on the F factor to the F- cell. After conjugation, the F- cell will contain a part of the Hfr chromosome, the exogenote, as well as its own genomic chromosome, the endogenote. At this stage the cell is called a merozygote. This temporary partial diploid state may lead to recombination between the corresponding portions of the DNA, so that the genetic material of the donor may be incorporated into the chromosome of the recipient, thereby altering the genotype of the recipient. However, if no recombination occurs, the linear fragment of donor DNA in the recipient cytoplasm will be lost after one cycle. These merozygotes help to study dominance variation and mutation can be known.
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https://en.wikipedia.org/wiki/Topology%20%28journal%29
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Topology was a peer-reviewed mathematical journal covering topology and geometry. It was established in 1962 and was published by Elsevier. The last issue of Topology appeared in 2009.
Pricing dispute
On 10 August 2006, after months of unsuccessful negotiations with Elsevier about the price policy of library subscriptions, the entire editorial board of the journal handed in their resignation, effective 31 December 2006. Subsequently, two more issues appeared in 2007 with papers that had been accepted before the resignation of the editors. In early January the former editors instructed Elsevier to remove their names from the website of the journal, but Elsevier refused to comply, justifying their decision by saying that the editorial board should remain on the journal until all of the papers accepted during its tenure had been published.
In 2007 the former editors of Topology announced the launch of the Journal of Topology, published by Oxford University Press on behalf of the London Mathematical Society at a significantly lower price. Its first issue appeared in January 2008.
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https://en.wikipedia.org/wiki/Easton%27s%20theorem
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In set theory, Easton's theorem is a result on the possible cardinal numbers of powersets. (extending a result of Robert M. Solovay) showed via forcing that the only constraints on permissible values for 2κ when κ is a regular cardinal are
(where cf(α) is the cofinality of α) and
Statement
If G is a class function whose domain consists of ordinals and whose range consists of ordinals such that
G is non-decreasing,
the cofinality of is greater than for each α in the domain of G, and
is regular for each α in the domain of G,
then there is a model of ZFC such that
for each in the domain of G.
The proof of Easton's theorem uses forcing with a proper class of forcing conditions over a model satisfying the generalized continuum hypothesis.
The first two conditions in the theorem are necessary. Condition 1 is a well known property of cardinality, while condition 2 follows from König's theorem.
In Easton's model the powersets of singular cardinals have the smallest possible cardinality compatible with the conditions that 2κ has cofinality greater than κ and is a non-decreasing function of κ.
No extension to singular cardinals
proved that a singular cardinal of uncountable cofinality cannot be the smallest cardinal for which the generalized continuum hypothesis fails. This shows that Easton's theorem cannot be extended to the class of all cardinals. The program of PCF theory gives results on the possible values of for singular cardinals . PCF theory shows that the values of the continuum function on singular cardinals are strongly influenced by the values on smaller cardinals, whereas Easton's theorem shows that the values of the continuum function on regular cardinals are only weakly influenced by the values on smaller cardinals.
See also
Singular cardinal hypothesis
Aleph number
Beth number
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https://en.wikipedia.org/wiki/RC%20algorithm
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The RC algorithms are a set of symmetric-key encryption algorithms invented by Ron Rivest. The "RC" may stand for either Rivest's cipher or, more informally, Ron's code. Despite the similarity in their names, the algorithms are for the most part unrelated. There have been six RC algorithms so far:
RC1 was never published.
RC2 was a 64-bit block cipher developed in 1987.
RC3 was broken before ever being used.
RC4 is a stream cipher.
RC5 is a 32/64/128-bit block cipher developed in 1994.
RC6, a 128-bit block cipher based heavily on RC5, was an AES finalist developed in 1997.
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https://en.wikipedia.org/wiki/Bird%E2%80%93Meertens%20formalism
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The Bird–Meertens formalism (BMF) is a calculus for deriving programs from program specifications (in a functional programming setting) by a process of equational reasoning. It was devised by Richard Bird and Lambert Meertens as part of their work within IFIP Working Group 2.1.
It is sometimes referred to in publications as BMF, as a nod to Backus–Naur form. Facetiously it is also referred to as Squiggol, as a nod to ALGOL, which was also in the remit of WG 2.1, and because of the "squiggly" symbols it uses. A less-used variant name, but actually the first one suggested, is SQUIGOL.
Basic examples and notations
Map is a well-known second-order function that applies a given function to every element of a list; in BMF, it is written :
Likewise, reduce is a function that collapses a list into a single value by repeated application of a binary operator. It is written / in BMF.
Taking as a suitable binary operator with neutral element e, we have
Using those two operators and the primitives (as the usual addition), and (for list concatenation), we can easily express the sum of all elements of a list, and the flatten function, as and , in
point-free style. We have:
Similarly, writing for functional composition and for conjunction, it is easy to write a function testing that all elements of a list satisfy a predicate p, simply as :
Bird (1989) transforms inefficient easy-to-understand expressions ("specifications") into efficient involved expressions ("programs") by algebraic manipulation. For example, the specification "" is an almost literal translation of the maximum segment sum problem, but running that functional program on a list of size will take time in general. From this, Bird computes an equivalent functional program that runs in time , and is in fact a functional version of Kadane's algorithm.
The derivation is shown in the picture, with computational complexities given in blue, and law applications indicated in red.
Example instances of the laws c
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https://en.wikipedia.org/wiki/Narus%20Inc.
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Narus Inc. was a software company and vendor of big data analytics for cybersecurity.
History
In 1997, Ori Cohen, Vice President of Business and Technology Development for VDONet, founded Narus with Stas Khirman in Israel. Presently, they are employed with Deutsche Telekom AG and are not members of Narus' executive team. In 2010, Narus became a subsidiary of Boeing, located in Sunnyvale, California. In 2015, Narus was sold to Symantec.
Here are some of the key events in Narus's history:
1997: Narus is founded.
2001: Narus's products are used to track the September 11th terrorist attacks.
2004: Narus's products are used to track the spread of the Stuxnet worm.
2014: Narus is acquired by Boeing.
2015: Boeing's Phantom Works Intelligence & Analytics business is formed.
Narus was a pioneer in the field of big data analytics for cybersecurity. The company's products helped to protect organizations from a variety of cyber threats. Narus's products are no longer available, but Boeing's Phantom Works Intelligence & Analytics business continues to offer cybersecurity solutions.
Management
In 2004, Narus employed former Deputy Director of the National Security Agency, William Crowell as a director. From the Press Release announcing this:
Narus software
Narus software primarily captures various computer network traffic in real-time and analyzes results.
Before 9/11 Narus built carrier-grade tools to analyze IP network traffic for billing purposes, to prevent what Narus called "revenue leakage". Post-9/11 Narus added more "semantic monitoring abilities" for surveillance.
Mobile
Narus provided Telecom Egypt with deep packet inspection equipment, a content-filtering technology that allows network managers to inspect, track and target content from users of the Internet and mobile phones, as it passes through routers. The national telecommunications authorities of both Pakistan and Saudi Arabia are global Narus customers.
Controversies
AT&T wiretapping room
Narus s
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https://en.wikipedia.org/wiki/Low-energy%20electron%20diffraction
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Low-energy electron diffraction (LEED) is a technique for the determination of the surface structure of single-crystalline materials by bombardment with a collimated beam of low-energy electrons (30–200 eV) and observation of diffracted electrons as spots on a fluorescent screen.
LEED may be used in one of two ways:
Qualitatively, where the diffraction pattern is recorded and analysis of the spot positions gives information on the symmetry of the surface structure. In the presence of an adsorbate the qualitative analysis may reveal information about the size and rotational alignment of the adsorbate unit cell with respect to the substrate unit cell.
Quantitatively, where the intensities of diffracted beams are recorded as a function of incident electron beam energy to generate the so-called I–V curves. By comparison with theoretical curves, these may provide accurate information on atomic positions on the surface at hand.
Historical perspective
An electron-diffraction experiment similar to modern LEED was the first to observe the wavelike properties of electrons, but LEED was established as an ubiquitous tool in surface science only with the advances in vacuum generation and electron detection techniques.
Davisson and Germer's discovery of electron diffraction
The theoretical possibility of the occurrence of electron diffraction first emerged in 1924, when Louis de Broglie introduced wave mechanics and proposed the wavelike nature of all particles. In his Nobel-laureated work de Broglie postulated that the wavelength of a particle with linear momentum p is given by h/p, where h is Planck's constant.
The de Broglie hypothesis was confirmed experimentally at Bell Labs in 1927, when Clinton Davisson and Lester Germer fired low-energy electrons at a crystalline nickel target and observed that the angular dependence of the intensity of backscattered electrons showed diffraction patterns. These observations were consistent with the diffraction theory for X-rays devel
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https://en.wikipedia.org/wiki/Virtually%20Haken%20conjecture
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In topology, an area of mathematics, the virtually Haken conjecture states that every compact, orientable, irreducible three-dimensional manifold with infinite fundamental group is virtually Haken. That is, it has a finite cover (a covering space with a finite-to-one covering map) that is a Haken manifold.
After the proof of the geometrization conjecture by Perelman, the conjecture was only open for hyperbolic 3-manifolds.
The conjecture is usually attributed to Friedhelm Waldhausen in a paper from 1968, although he did not formally state it. This problem is formally stated as Problem 3.2 in Kirby's problem list.
A proof of the conjecture was announced on March 12, 2012 by Ian Agol in a seminar lecture he gave at the Institut Henri Poincaré. The proof appeared shortly thereafter in a preprint which was eventually published in Documenta Mathematica. The proof was obtained via a strategy by previous work of Daniel Wise and collaborators, relying on actions of the fundamental group on certain auxiliary spaces (CAT(0) cube complexes)
It used as an essential ingredient the freshly-obtained solution to the surface subgroup conjecture by Jeremy Kahn and Vladimir Markovic.
Other results which are directly used in Agol's proof include the Malnormal Special Quotient Theorem of Wise and a criterion of Nicolas Bergeron and Wise for the cubulation of groups.
In 2018 related results were obtained by Piotr Przytycki and Daniel Wise proving that mixed 3-manifolds are also virtually special, that is they can be cubulated into a cube complex with a finite cover where all the hyperplanes are embedded which by the previous mentioned work can be made virtually Haken.
See also
Virtually fibered conjecture
Surface subgroup conjecture
Ehrenpreis conjecture
Notes
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https://en.wikipedia.org/wiki/Shear%20pin
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A shear pin is a mechanical detail designed to allow a specific outcome to occur once a predetermined force is applied. It can either function as a safeguard designed to break to protect other parts, or as a conditional operator that will not allow a mechanical device to operate until the correct force is applied.
As safeguards
In the role of a mechanical safeguard, a shear pin is a safety device designed to shear in the case of a mechanical overload, preventing other, more expensive or less-easily replaced parts from being damaged. As a mechanical sacrificial part, it is analogous to an electric fuse.
They are most commonly used in drive trains, such as a snow blower's auger or the propellers attached to marine engines.
Another use is in pushback bars used for large aircraft. In this device, shear pins are frequently used to connect the "head" of the towbar – the portion that attaches to the aircraft – to the main shaft of the towbar. In this way, the failure of the shear pin will physically separate the aircraft and the tractor. The design may be such that the shear pin will have several different causes of failure – towbar rotation about its long axis, sudden braking or acceleration, excessive steering force, etc. – all of which could otherwise be extremely damaging to the aircraft.
As conditional operators
In the role as a conditional operator, a shear pin will be used to prevent a mechanical device from operating before the criteria for operation are met. A shear pin gives a distinct threshold for the force required for operation. It is very cheap and easy to produce delivering a very high reliability and predictable tolerance. They are almost maintenance-free and can remain ready for operation for years with little to no decrease in reliability. Shear pins are only useful for a single operating cycle, after each operation they have to be replaced. A very simple example is the plastic or wire loop affixed to the handles of common fire extinguishers. Its pre
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https://en.wikipedia.org/wiki/Page%20orientation
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Page orientation is the way in which a rectangular page is oriented for normal viewing. The two most common types of orientation are portrait and landscape. The term "portrait orientation" comes from visual art terminology and describes the dimensions used to capture a person's face and upper body in a picture; in such images, the height of the display area is greater than the width. The term "landscape orientation" also reflects visual art terminology, where pictures with more width than height are needed to fully capture the horizon within an artist's view.
Besides describing the way documents can be viewed and edited, the concepts of "portrait" and "landscape" orientation can also be used to describe video and photography display options (where the concept of "aspect ratio" replaces that of "page orientation"). Many types of visual media use landscape mode, especially the 4:3 aspect ratio used for classic TV formatting, which is 4 units or pixels wide and 3 units tall, and the 16:9 aspect ratio for newer, widescreen media viewing.
Most paper documents use portrait orientation. By default, most computer and television displays use landscape orientation, while most mobile phones use portrait orientation (with some flexibility on modern smartphones to switch screen orientations according to user preference). Portrait mode is preferred for editing page layout work, in order to view the entire page of a screen at once without showing wasted space outside the borders of a page, and for script-writing, legal work (in drafting contracts etc.), and other applications where it is useful to see a maximum number of lines of text. It is also preferred for smartphone use, as a phone in portrait orientation can be operated easily with one hand. Landscape viewing, on the other hand, visually caters to the natural horizontal alignment of human eyes at the same time landscape details are much wider than they are taller, and is therefore useful for portraying wider visuals with
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https://en.wikipedia.org/wiki/Tournament%20of%20the%20Gods
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is a H-game by Alicesoft.
Plot
Sid enters a tournament. Shortly after he is crowned champion, the fallen Angel Aquross infects him with a hideous disease that requires him to steal the life energy of Angels or be in constant pain. The only relief lies in a drug that kills the pain, but causes sexual urges that cannot be denied. Now, Sid must defeat the evil Aquross.
OVA
It was condensed into a single 35-minute episode and released in the US as a subtitled white-cassette VHS by Pink Pineapple studio.
Episodes
Theme songs
"Yume no Image" by Konami Yoshida
Cast
Reception
Mike Toole comparing the OVA to Gor did not find it very interesting. Chris Beveridge commented that the video "is a strange piece" and has "some good fun moments".
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https://en.wikipedia.org/wiki/Testicular%20microlithiasis
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Testicular microlithiasis is an unusual condition diagnosed on testicular ultrasound. It is believed to be found in 0.1–0.6% of males globally, with frequency varying based on geographic location and is more often found in individuals with subfertility. It is a often an asymptomatic, non-progressive disease; though in a very small number of cases it may also cause bouts of extreme chronic fatigue, hormone imbalance and pain, which can be severe and accompanied by swelling around the testicular region (dependent on the size and location of the calcification). In an extremely rare select few cases, individuals with microlithiasis have also been known to experience calcification of the prostate, which can lead to the passing of stones. These rare cases can lead to secondary infections if not treated with care, due to the resulting damaged tissue. It is important to note however that these symptoms are rarely seen in the majority of people who have been diagnosed.
Testicular microlithiasis is not associated with risk of testicular cancer in asymptomatic individuals. However, a large meta-analysis has shown that in individuals with associated risk factors for testicular germ cell tumor, the increase in risk of concurrent diagnosis of testicular germ cell tumor, or testicular carcinoma-in-situ upon biopsy is approximately eight to ten-fold.
There is extensive controversy over whether testicular microlithiasis in individuals with testicular germ cell tumor, or risk factors for such, should undergo testicular biopsy to exclude the presence of testicular carcinoma in situ, also known as intratubular germ cell neoplasia of unclassified type. Additionally, whether the presence of testicular microlithiasis should influence decision for adjuvant chemotherapy or surveillance in individuals with testicular germ cell tumor remains unclear. A recent review in Nature Reviews Urology has comprehensively evaluated these topics. It is important to note however as with any condition th
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https://en.wikipedia.org/wiki/Bounded%20mean%20oscillation
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In harmonic analysis in mathematics, a function of bounded mean oscillation, also known as a BMO function, is a real-valued function whose mean oscillation is bounded (finite). The space of functions of bounded mean oscillation (BMO), is a function space that, in some precise sense, plays the same role in the theory of Hardy spaces Hp that the space L∞ of essentially bounded functions plays in the theory of Lp-spaces: it is also called John–Nirenberg space, after Fritz John and Louis Nirenberg who introduced and studied it for the first time.
Historical note
According to , the space of functions of bounded mean oscillation was introduced by in connection with his studies of mappings from a bounded set belonging to Rn into Rn and the corresponding problems arising from elasticity theory, precisely from the concept of elastic strain: the basic notation was introduced in a closely following paper by , where several properties of this function spaces were proved. The next important step in the development of the theory was the proof by Charles Fefferman of the duality between BMO and the Hardy space H1, in the noted paper : a constructive proof of this result, introducing new methods and starting a further development of the theory, was given by Akihito Uchiyama.
Definition
The mean oscillation of a locally integrable function u over a hypercube Q in Rn is defined as the value of the following integral:
where
|Q| is the volume of Q, i.e. its Lebesgue measure
uQ is the average value of u on the cube Q, i.e.
A BMO function is a locally integrable function u whose mean oscillation supremum, taken over the set of all cubes Q contained in Rn, is finite.
Note 1. The supremum of the mean oscillation is called the BMO norm of u. and is denoted by ||u||BMO (and in some instances it is also denoted ||u||∗).
Note 2. The use of cubes Q in Rn as the integration domains on which the is calculated, is not mandatory: uses balls instead and, as remarked by , in doing so a
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https://en.wikipedia.org/wiki/Gliosis
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Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes. In its most extreme form, the proliferation associated with gliosis leads to the formation of a glial scar.
The process of gliosis involves a series of cellular and molecular events that occur over several days. Typically, the first response to injury is the migration of macrophages and local microglia to the injury site. This process, which constitutes a form of gliosis known as microgliosis, begins within hours of the initial CNS injury. Later, after 3–5 days, oligodendrocyte precursor cells are also recruited to the site and may contribute to remyelination. The final component of gliosis is astrogliosis, the proliferation of surrounding astrocytes, which are the main constituents of the glial scar.
Gliosis has historically been given a negative connotation due to its appearance in many CNS diseases and the inhibition of axonal regeneration caused by glial scar formation. However, gliosis has been shown to have both beneficial and detrimental effects, and the balance between these is due to a complex array of factors and molecular signaling mechanisms, which affect the reaction of all glial cell types.
Astrogliosis
Reactive astrogliosis is the most common form of gliosis and involves the proliferation of astrocytes, a type of glial cell responsible for maintaining extracellular ion and neurotransmitter concentrations, modulating synapse function, and forming the blood–brain barrier. Like other forms of gliosis, astrogliosis accompanies traumatic brain injury as well as many neuropathologies, ranging from amyotrophic lateral sclerosis to fatal familial insomnia. Although the mechanisms which lead to astrogliosis are not fully understood, neuronal injury is well understood to cause astrocy
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