source stringlengths 31 227 | text stringlengths 9 2k |
|---|---|
https://en.wikipedia.org/wiki/Multi-configuration%20time-dependent%20Hartree | Multi-configuration time-dependent Hartree (MCTDH) is a general algorithm to solve the time-dependent Schrödinger equation for multidimensional dynamical systems consisting of distinguishable particles. MCTDH can thus determine the quantal motion of the nuclei of a molecular system evolving on one or several coupled electronic potential energy surfaces. MCTDH by its very nature is an approximate method. However, it can be made as accurate as any competing method, but its numerical efficiency deteriorates with growing accuracy.
MCTDH is designed for multi-dimensional problems, in particular for problems that are difficult or even impossible to attack in a conventional way. There is no or only little gain when treating systems with less than three degrees of freedom by MCTDH. MCTDH will in general be best suited for systems with 4 to 12 degrees of freedom. Because of hardware limitations it may in general not be possible to treat much larger systems. For a certain class of problems, however, one can go much further. The MCTDH program package has recently been generalised to enable the propagation of density operators. |
https://en.wikipedia.org/wiki/Tensor%20tympani%20muscle | The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunder. Because its reaction time is not fast enough, the muscle cannot protect against hearing damage caused by sudden loud sounds, like explosions or gunshots.
Structure
The tensor tympani is a muscle that is present in the middle ear. It arises from the cartilaginous part of the auditory tube, and the adjacent great wing of the sphenoid. It then passes through its own canal, and ends in the tympanic cavity as a slim tendon that connects to the handle of the malleus. The tendon makes a sharp bend around the processus cochleariformis, part of the wall of its cavity, before it joins with the malleus.
The tensor tympani receives blood from the middle meningeal artery via the superior tympanic branch. It is one of two muscles in the tympanic cavity, the other being the stapedius.
Nerve supply
The tensor tympani is supplied by the tensor tympani nerve, a branch of the mandibular branch of the trigeminal nerve. As the tensor tympani is supplied by motor fibers of the trigeminal nerve, it does not receive fibers from the trigeminal ganglion, which has sensory fibers only.
Development
The tensor tympani muscle develops from mesodermal tissue in the 1st pharyngeal arch.
Function
The tensor tympani acts to dampen the noise produced by chewing. When tensed, the muscle pulls the malleus medially, tensing the tympanic membrane and damping vibration in the ear ossicles and thereby reducing the perceived amplitude of sounds. It is not to be confused by the acoustic reflex, but can be activated by the startle reflex.
Voluntary control
Contracting muscles produce vibration and sound. Slow twitch fibers produce 10 to 30 contractions per second (equivalent to 10 to 30 Hz sound frequency). Fast twitch fibers produce 30 to 70 contractions |
https://en.wikipedia.org/wiki/Diminazene | Diminazene (INN; also known as diminazen) is an anti-infective medication for animals that is sold under a variety of brand names. It is effective against certain protozoa such as Babesia, Trypanosoma, and Cytauxzoon. The drug may also be effective against certain bacteria including Brucella and Streptococcus.
Chemically it is a di-amidine and it is formulated as its aceturate salt, diminazene aceturate.
The mechanism is not well understood; it probably inhibits DNA replication, but also has affinity to RNA.
Side effects
Acute side effects include vomiting, diarrhea, and hypotension (low blood pressure). Diminazen can harm the liver, kidneys and brain, which is potentially life-threatening; camels are especially susceptible to these effects.
Resistance
The Gibe River Valley in southwest Ethiopia showed universal resistance between July 1989 and February 1993. This likely indicates a permanent loss of function in this area against the tested target, T. congolense isolated from Boran cattle. |
https://en.wikipedia.org/wiki/Kainate%20receptor | Kainate receptors, or kainic acid receptors (KARs), are ionotropic receptors that respond to the neurotransmitter glutamate. They were first identified as a distinct receptor type through their selective activation by the agonist kainate, a drug first isolated from the algae Digenea simplex. They have been traditionally classified as a non-NMDA-type receptor, along with the AMPA receptor. KARs are less understood than AMPA and NMDA receptors, the other ionotropic glutamate receptors. Postsynaptic kainate receptors are involved in excitatory neurotransmission. Presynaptic kainate receptors have been implicated in inhibitory neurotransmission by modulating release of the inhibitory neurotransmitter GABA through a presynaptic mechanism.
Structure
There are five types of kainate receptor subunits, GluR5 (), GluR6 (), GluR7 (), KA1 () and KA2 (), which are similar to AMPA and NMDA receptor subunits and can be arranged in different ways to form a tetramer, a four subunit receptor. GluR5-7 can form homomers (ex. a receptor composed entirely of GluR5) and heteromers (ex. a receptor composed of both GluR5 and GluR6), however, KA1 and KA2 can only form functional receptors by combining with one of the GluR5-7 subunits.
Since 2009 the kainate receptor subunits have been renamed to correspond with their gene name. Hence GluR5-7 are now GluK1-3 and KA1 and KA2 are GluK4 and GluK5, respectively.
Each KAR subunit begins with a 400-residue extracellular N-terminal domain, which plays a key role in assembly, followed by the first segment of the neurotransmitter-binding cleft, called S1. This segment then passes through the cell membrane, forming the first of three membrane-spanning regions, M1. The M2 segment then begins on the cytoplasmic face of the membrane, pushes into the cell membrane about half way, and then dips back out to the cytoplasm. This segment, termed the "p loop," determines the calcium permeability of the receptor. M2 turns into M3, another transmembrane segmen |
https://en.wikipedia.org/wiki/Bioprocessor | A bioprocessor is a miniaturized bioreactor capable of culturing mammalian, insect and microbial cells. Bioprocessors are capable of mimicking performance of large-scale bioreactors, hence making them ideal for laboratory scale experimentation of cell culture processes. Bioprocessors are also used for concentrating bioparticles (such as cells) in bioanalytical systems. Microfluidic processes such as electrophoresis can be implemented by bioprocessors to aid in DNA isolation and purification. |
https://en.wikipedia.org/wiki/Ciphertext%20indistinguishability | Ciphertext indistinguishability is a property of many encryption schemes. Intuitively, if a cryptosystem possesses the property of indistinguishability, then an adversary will be unable to distinguish pairs of ciphertexts based on the message they encrypt. The property of indistinguishability under chosen plaintext attack is considered a basic requirement for most provably secure public key cryptosystems, though some schemes also provide indistinguishability under chosen ciphertext attack and adaptive chosen ciphertext attack. Indistinguishability under chosen plaintext attack is equivalent to the property of semantic security, and many cryptographic proofs use these definitions interchangeably.
A cryptosystem is considered secure in terms of indistinguishability if no adversary, given an encryption of a message randomly chosen from a two-element message space determined by the adversary, can identify the message choice with probability significantly better than that of random guessing (). If any adversary can succeed in distinguishing the chosen ciphertext with a probability significantly greater than , then this adversary is considered to have an "advantage" in distinguishing the ciphertext, and the scheme is not considered secure in terms of indistinguishability. This definition encompasses the notion that in a secure scheme, the adversary should learn no information from seeing a ciphertext. Therefore, the adversary should be able to do no better than if it guessed randomly.
Formal definitions
Security in terms of indistinguishability has many definitions, depending on assumptions made about the capabilities of the attacker. It is normally presented as a game, where the cryptosystem is considered secure if no adversary can win the game with significantly greater probability than an adversary who must guess randomly. The most common definitions used in cryptography are indistinguishability under chosen plaintext attack (abbreviated IND-CPA), indistinguishabil |
https://en.wikipedia.org/wiki/DBFS | Decibels relative to full scale (dBFS or dB FS) is a unit of measurement for amplitude levels in digital systems, such as pulse-code modulation (PCM), which have a defined maximum peak level. The unit is similar to the units dBov and decibels relative to overload (dBO).
The level of 0dBFS is assigned to the maximum possible digital level. For example, a signal that reaches 50% of the maximum level has a level of −6dBFS, which is 6dB below full scale. Conventions differ for root mean square (RMS) measurements, but all peak measurements smaller than the maximum are negative levels.
A digital signal that does not contain any samples at 0dBFS can still clip when converted to analog form due to the signal reconstruction process interpolating between samples. This can be prevented by careful digital-to-analog converter circuit design. Measurements of the true inter-sample peak levels are notated as dBTP or dB TP ("decibels true peak").
RMS levels
Since a peak measurement is not useful for qualifying the noise performance of a system, or measuring the loudness of an audio recording, for instance, RMS measurements are often used instead.
A potential for ambiguity exists when assigning a level on the dBFS scale to a waveform rather than to a specific amplitude, because some engineers follow the mathematical definition of RMS, which for sinusoidal signals is −3dB below the peak value, while others choose the reference level so that RMS and peak measurements of a sine wave produce the same result.
The unit dB FS or dBFS is defined in AES Standard AES17-1998, IEC 61606, and ITU-T Recs. P.381 and P.382, such that the RMS value of a full-scale sine wave is designated 0dB FS. This means a full-scale square wave would have an RMS value of +3dB FS. This convention is used in Wolfson and Cirrus Logic digital microphone specs, etc.
The unit dBov is defined in the ITU-T G.100.1 telephony standard such that the RMS value of a full-scale square wave is designated 0dBov. All po |
https://en.wikipedia.org/wiki/Neuronal%20ceroid%20lipofuscinosis | Neuronal ceroid lipofuscinosis is the general name for a family of at least eight genetically separate neurodegenerative lysosomal storage diseases that result from excessive accumulation of lipopigments (lipofuscin) in the body's tissues. These lipopigments are made up of fats and proteins. Their name comes from the word stem "lipo-", which is a variation on lipid, and from the term "pigment", used because the substances take on a greenish-yellow color when viewed under an ultraviolet light microscope. These lipofuscin materials build up in neuronal cells and many organs, including the liver, spleen, myocardium, and kidneys.
Signs and symptoms
The classic characterization of the group of neurodegenerative, lysosomal storage disorders called the neuronal ceroid lipofuscinoses (NCLs) is through the progressive, permanent loss of motor and psychological ability with a severe intracellular accumulation of lipofuscins, with the United States and Northern European populations having slightly higher frequency with an occurrence of one in 10,000. Four classic diagnoses have received the most attention from researchers and the medical field, differentiated from one another by age of symptomatic onset, duration, early-onset manifestations such as blindness or seizures, and the forms which lipofuscin accumulation takes.
In the early infantile variant of NCL (also called INCL or Santavuori-Haltia), probands appear normal at birth, but early visual loss leading to complete retinal blindness by the age of 2 years is the first indicator of the disease; by 3 years of age, a vegetative state is reached, and by 4 years, isoelectric encephalograms confirm brain death. Late infantile variant usually manifests between 2 and 4 years of age with seizures and deterioration of vision. The maximum age before death for late infantile variant is 10–12 years. Juvenile NCL (JNCL, Batten disease, or Spielmeyer-Vogt), with a prevalence of one in 100,000, usually arises between 4 and 10 years o |
https://en.wikipedia.org/wiki/Universal%20Satellites%20Automatic%20Location%20System | Universal Satellites Automatic Location System (USALS), also known (unofficially) as DiSEqC 1.3, Go X or Go to XX is a satellite dish motor protocol that automatically creates a list of available satellite positions in a motorised satellite dish setup. It is used in conjunction with the DiSEqC 1.2 protocol. It was developed by STAB, an Italian motor manufacturer, who still make the majority of USALS compatible motors.
Software on the satellite receiver (or external positioner) calculates the position of all available satellites from an initial location (input by the user), which is the latitude and longitude relative to Earth. Calculated positions can differ ±0.1 degrees from the offset. This is adjusted automatically and does not require previous technical knowledge.
Compared to DiSEqC 1.2, it is not necessary to manually search and store every known satellite position. Pointing to a known satellite position (for example 19.2ºE) is enough; this position will act as the central point, and the USALS system will then calculate visible satellites position within the offset.
Receivers are aligned to the satellite most southern to their position in the northern hemisphere, or the northernmost in the southern hemisphere.
As it is not an open standard, for a receiver to carry the USALS logo it must undergo a certification test by STAB's laboratories. If successful the manufacturer can include a USALS settings entry in its own menu, as well as place the logo on the front of their unit. However, a large number of manufacturers of both receivers and motors provide compatible modes which have not received certification, leading to use of unofficial terms.
USALS is a program and not a communication protocol. The USALS calculates the dish angular position given by the dish longitude/latitude and the position of the satellite in geostationary orbit. It then sends the angular position to the positioner using the DiSEqC 1.2 protocol. This calculation is straight on using geo |
https://en.wikipedia.org/wiki/Dancing%20mania | Dancing mania (also known as dancing plague, choreomania, St. John's Dance, tarantism and St. Vitus' Dance) was a social phenomenon that occurred primarily in mainland Europe between the 14th and 17th centuries. It involved groups of people dancing erratically, sometimes thousands at a time. The mania affected adults and children who danced until they collapsed from exhaustion and injuries. One of the first major outbreaks was in Aachen, in the Holy Roman Empire (in modern-day Germany), in 1374, and it quickly spread throughout Europe; one particularly notable outbreak occurred in Strasbourg in 1518 in Alsace, also in the Holy Roman Empire (now in modern-day France).
Affecting thousands of people across several centuries, dancing mania was not an isolated event, and was well documented in contemporary reports. It was nevertheless poorly understood, and remedies were based on guesswork. Often musicians accompanied dancers, due to a belief that music would treat the mania, but this tactic sometimes backfired by encouraging more to join in. There is no consensus among modern-day scholars as to the cause of dancing mania.
The several theories proposed range from religious cults being behind the processions to people dancing to relieve themselves of stress and put the poverty of the period out of their minds. It is speculated to have been a mass psychogenic illness, in which physical symptoms with no known physical cause are observed to affect a group of people, as a form of social influence.
Definition
"Dancing mania" is derived from the term "choreomania", from the Greek choros (dance) and mania (madness), and is also known as "dancing plague". The term was coined by Paracelsus, and the condition was initially considered a curse sent by a saint, usually St. John the Baptist or St. Vitus, and was therefore known as "St. Vitus' Dance" or "St. John's Dance". Victims of dancing mania often ended their processions at places dedicated to that saint, who was prayed to in a |
https://en.wikipedia.org/wiki/Cornus%20canadensis | Cornus canadensis is a species of flowering plant in the dogwood family Cornaceae, native to eastern Asia and North America. Common names include Canadian dwarf cornel, Canadian bunchberry, quatre-temps, crackerberry, and creeping dogwood. Unlike its relatives, which are for the most part substantial trees and shrubs, C. canadensis is a creeping, rhizomatous perennial growing to about tall.
Description
Cornus canadensis is a slow-growing herbaceous perennial growing tall, generally forming a carpet-like mat. The above-ground shoots rise from slender creeping rhizomes that are placed deep in the soil, and form clonal colonies under trees. The vertically produced above-ground stems are slender and unbranched. Produced near the terminal node, the leaves are shiny dark green and arranged oppositely on the stem, clustered with six leaves that often seem to be in a whorl because the internodes are compressed. The leaves consist of two types: two larger and four smaller leaves; the smaller ones develop from the axillary buds of the larger leaves. The leaves have petioles in length and leaf blades that are obovate. The blades have entire margins and are long and wide, with 2–3 veins, cuneate shaped bases and abruptly acuminate apexes. In autumn, the leaves have red-tinted veins and turn completely red.
Flowers
In late spring to midsummer, white flowers are produced that are in diameter with reflexed petals that are ovate-lanceolate in shape and long. The inflorescences are made up of compound terminal cymes, with large showy white bracts that resemble petals. The bracts are green when immature. The bracts are broadly ovate and long and wide, with 7 parallel running veins. The lower nodes on the stem have greatly reduced rudimentary leaves. The calyx tube is obovate in shape and 1 mm long, covered with densely pubescent hairs along with grayish white appressed trichomes. Stamens are very short, being 1 mm long. The anthers are yellowish white in color, narrowly |
https://en.wikipedia.org/wiki/Drinking%20bird | Drinking birds, also known as insatiable birdies, dunking birds, drinky birds, water birds, dipping birds, and “Sippy Chickens” are toy heat engines that mimic the motions of a bird drinking from a water source. They are sometimes incorrectly considered examples of a perpetual motion device.
Construction and materials
A drinking bird consists of two glass bulbs joined by a glass tube (the bird's neck/body). The tube extends nearly all the way into the bottom bulb, and attaches to the top bulb but does not extend into it.
The space inside the bird contains a fluid, usually colored for visibility. (This dye might fade when exposed to light, with the rate depending on the dye/color).
The fluid is typically dichloromethane (DCM), also known as methylene chloride.
Earlier versions contained trichlorofluoromethane.
Miles V. Sullivan's 1945 patent suggested ether, alcohol, carbon tetrachloride, or chloroform.
Air is removed from the apparatus during manufacture, so the space inside the body is filled by vapor evaporated from the fluid. The upper bulb has a "beak" attached which, along with the head, is covered in a felt-like material. The bird is typically decorated with paper eyes, a plastic top hat, and one or more tail feathers. The whole device pivots on a crosspiece attached to the body.
Heat engine steps
The drinking bird is a heat engine that exploits a temperature difference to convert heat energy to a pressure difference within the device, and performs mechanical work. Like all heat engines, the drinking bird works through a thermodynamic cycle. The initial state of the system is a bird with a wet head oriented vertically.
The process operates as follows:
The water evaporates from the felt on the head.
Evaporation lowers the temperature of the glass head (heat of vaporization).
The temperature decrease causes some of the dichloromethane vapor in the head to condense.
The lower temperature and condensation together cause the pressure to drop in the head |
https://en.wikipedia.org/wiki/Western%20Latin%20character%20sets%20%28computing%29 | Several 8-bit character sets (encodings) were designed for binary representation of common Western European languages (Italian, Spanish, Portuguese, French, German, Dutch, English, Danish, Swedish, Norwegian, and Icelandic), which use the Latin alphabet, a few additional letters and ones with precomposed diacritics, some punctuation, and various symbols (including some Greek letters). These character sets also happen to support many other languages such as Malay, Swahili, and Classical Latin.
This material is technically obsolete, having been functionally replaced by Unicode. However it continues to have historical interest.
Summary
The ISO-8859 series of 8-bit character sets encodes all Latin character sets used in Europe, albeit that the same code points have multiple uses that caused some difficulty (including mojibake, or garbled characters, and communication issues). The arrival of Unicode, with a unique code point for every glyph, resolved these issues.
ISO/IEC 8859-1 or Latin-1 is the most used and also defines the first 256 codepoints in Unicode.
ISO/IEC 8859-15 modifies ISO-8859-1 to fully support Estonian, Finnish and French and add the euro sign.
Windows-1252 is a superset of ISO-8859-1 that includes the printable characters from ISO/IEC 8859-15 and popular punctuation such as curved quotation marks (also known as smart quotes, such as in Microsoft Word settings and similar programs). It is common that web page tools for Windows use Windows-1252 but label the web page as using ISO-8859-1, this has been addressed in HTML5, which mandates that pages labeled as ISO-8859-1 must be interpreted as Windows-1252.
IBM CP437, being intended for English only, has very little in the way of accented letters (particularly uppercase) but has far more graphics characters than the other IBM code pages listed here and also some mathematical and Greek characters that are useful as technical symbols.
IBM CP850 has all the printable characters that ISO-8859-1 has |
https://en.wikipedia.org/wiki/IRC%20subculture | IRC subculture refers to the particular set of social features common to interaction on the various Internet Relay Chat (IRC) systems around the world, and the culture associated with them. IRC is particularly popular among programmers, hackers, and computer gamers.
Overview
Internet Relay Chat is an Internet-based chat system that has existed in one form or another since 1988. Networks are connected groups of IRC servers which share a common userbase. Channels are the "chat rooms" on said networks. IRC channel operators (commonly referred to as chops or chanops) are the individuals who run any given channel.
While there are many different IRC networks, and across those networks there are usually large numbers of IRC channels, there are some unifying features common to the social structures of them all. Many of the features of the IRC subculture mesh with other Internet subcultures, such as various forum subcultures. This is especially prevalent in IRC channels or networks that are directly related to other Internet phenomena, such as an IRC channel created by and for the users of a particular Internet forum.
Communication on IRC
IRC has much in common with a regular in-person conversation. It is real-time many-on-many communication that is not logged by the server for posterity (many IRC clients do offer a logging feature, but the logs aren't generally publicly available then). Some bots may also feature logging facilities. Users on IRC usually identify users as ones "saying" something (instead of posting it) to reflect the similarity with face-to-face communication.
Because IRC is a text-based communication medium, the obvious limitation of this metaphor is that the participants of a conversation on IRC do not actually see or hear each other, so alternative ways must be employed to convey the information that would otherwise be gained from facial expressions, tones of voice, and other audio-visual clues. It is common practice among IRC users to use emotico |
https://en.wikipedia.org/wiki/Microstructure | Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material (such as metals, polymers, ceramics or composites) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.
Microstructure at scales smaller than can be viewed with optical microscopes is often called nanostructure, while the structure in which individual atoms are arranged is known as crystal structure. The nanostructure of biological specimens is referred to as ultrastructure. A microstructure’s influence on the mechanical and physical properties of a material is primarily governed by the different defects present or absent of the structure. These defects can take many forms but the primary ones are the pores. Even if those pores play a very important role in the definition of the characteristics of a material, so does its composition. In fact, for many materials, different phases can exist at the same time. These phases have different properties and if managed correctly, can prevent the fracture of the material.
Methods
The concept of microstructure is observable in macrostructural features in commonplace objects. Galvanized steel, such as the casing of a lamp post or road divider, exhibits a non-uniformly colored patchwork of interlocking polygons of different shades of grey or silver. Each polygon is a single crystal of zinc adhering to the surface of the steel beneath. Zinc and lead are two common metals which form large crystals (grains) visible to the naked eye. The atoms in each grain are organized into one of seven 3d stacking arrangements or crystal lattices (cubic, tetrahedral, hexagonal, monoclinic, triclinic, rhombohedral and orthorhombic). |
https://en.wikipedia.org/wiki/Corner%20solution | In mathematics and economics, a corner solution is a special solution to an agent's maximization problem in which the quantity of one of the arguments in the maximized function is zero. In non-technical terms, a corner solution is when the chooser is either unwilling or unable to make a trade-off between goods.
In economics
In the context of economics the corner solution is best characterised by when the highest indifference curve attainable is not tangential to the budget line, in this scenario the consumer puts their entire budget into purchasing as much of one of the goods as possible and none of any other. When the slope of the indifference curve is greater than the slope of the budget line, the consumer is willing to give up more of good 1 for a unit of good 2 than is required by the market. Thus, it follows that if the slope of the indifference curve is strictly greater than the slope of the budget line:
Then the result will be a corner solution intersecting the x-axis. The converse is also true for a corner solution resulting from an intercept through the y-axis.
Examples
Real world examples of a corner solution occur when someone says "I wouldn't buy that at any price", "Why would I buy X when Y is cheaper" or "I will do X no matter the cost" , this could be for any number of reasons e.g. a bad brand experience, loyalty to a specific brand or when a cheaper version of the same good exists.
Another example is "zero-tolerance" policies, such as a parent who is unwilling to expose their children to any risk, no matter how small and no matter what the benefits of the activity might be. "Nothing is more important than my child's safety" is a corner solution in its refusal to admit there might be trade-offs. The term "corner solution" is sometimes used by economists in a more colloquial fashion to refer to these sorts of situations.
Another situation a corner solution may arise is when the two goods in question are perfect substitutes. The word "corner" re |
https://en.wikipedia.org/wiki/Comfort%20noise | Comfort noise (or comfort tone) is synthetic background noise used in radio and wireless communications to fill the artificial silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.
Some modern telephone systems (such as wireless and VoIP) use voice activity detection (VAD), a form of squelching where low volume levels are ignored by the transmitting device. In digital audio transmissions, this saves bandwidth of the communications channel by transmitting nothing when the source volume is under a certain threshold, leaving only louder sounds (such as the speaker's voice) to be sent. However, improvements in background noise reduction technologies can occasionally result in the complete removal of all noise. Although maximizing call quality is of primary importance, exhaustive removal of noise may not properly simulate the typical behavior of terminals on the PSTN system.
The result of receiving total silence, especially for a prolonged period, has a number of unwanted effects on the listener, including the following:
the listener may believe that the transmission has been lost, and therefore hang up prematurely
the speech may sound "choppy" (see noise gate) and difficult to understand
the sudden change in sound level can be jarring to the listener.
To counteract these effects, comfort noise is added, usually on the receiving end in wireless or VoIP systems, to fill in the silent portions of transmissions with artificial noise. The noise generated is at a low but audible volume level, and can vary based on the average volume level of received signals to minimize jarring transitions.
In many VoIP products, users may control how VAD and comfort noise are configured, or disable the feature entirely.
As part of the RTP audio video profile, RFC 3389 defines a standard for distributing comfort noise information in VoIP systems.
A similar concept is that of sidetone, the effect of sound that is picked |
https://en.wikipedia.org/wiki/Complete%20market | In economics, a complete market (aka Arrow-Debreu market or complete system of markets) is a market with two conditions:
Negligible transaction costs and therefore also perfect information,
Every asset in every possible state of the world has a price.
In such a market, the complete set of possible bets on future states of the world can be constructed with existing assets without friction. Here, goods are state-contingent; that is, a good includes the time and state of the world in which it is consumed. For instance, an umbrella tomorrow if it rains is a distinct good from an umbrella tomorrow if it is clear. The study of complete markets is central to state-preference theory. The theory can be traced to the work of Kenneth Arrow (1964), Gérard Debreu (1959), Arrow & Debreu (1954) and Lionel McKenzie (1954). Arrow and Debreu were awarded the Nobel Memorial Prize in Economics (Arrow in 1972, Debreu in 1983), largely for their work in developing the theory of complete markets and applying it to the problem of general equilibrium.
States of the world
A state of the world is a complete specification of the values of all relevant variables over the relevant time horizon. A state-contingent claim, or state claim, is a contract whose future payoffs depend on future states of the world. For example, suppose you can bet on the outcome of a coin toss. If you guess the outcome correctly, you will win one dollar, and otherwise you will lose one dollar. A bet on heads is a state claim, with payoff of one dollar if heads is the outcome, and payoff of negative one dollar if tails is the outcome. "Heads" and "tails" are the states of the world in this example. A state-contingent claim can be represented as a payoff vector with one element for each state of the world, e.g. (payoff if heads, payoff if tails). So a bet on heads can be represented as ($1, −$1) and a bet on tails can be represented as (−$1, $1). Notice that by placing one bet on heads and one bet on tails, you have |
https://en.wikipedia.org/wiki/Shephard%27s%20lemma | Shephard's lemma is a major result in microeconomics having applications in the theory of the firm and in consumer choice. The lemma states that if indifference curves of the expenditure or cost function are convex, then the cost minimizing point of a given good () with price is unique. The idea is that a consumer will buy a unique ideal amount of each item to minimize the price for obtaining a certain level of utility given the price of goods in the market.
The lemma is named after Ronald Shephard who gave a proof using the distance formula in his book Theory of Cost and Production Functions (Princeton University Press, 1953). The equivalent result in the context of consumer theory was first derived by Lionel W. McKenzie in 1957. It states that the partial derivatives of the expenditure function with respect to the prices of goods equal the Hicksian demand functions for the relevant goods. Similar results had already been derived by John Hicks (1939) and Paul Samuelson (1947).
Definition
In consumer theory, Shephard's lemma states that the demand for a particular good for a given level of utility and given prices , equals the derivative of the expenditure function with respect to the price of the relevant good:
where is the Hicksian demand for good , is the expenditure function, and both functions are in terms of prices (a vector ) and utility .
Likewise, in the theory of the firm, the lemma gives a similar formulation for the conditional factor demand for each input factor: the derivative of the cost function with respect to the factor price:
where is the conditional factor demand for input , is the cost function, and both functions are in terms of factor prices (a vector ) and output .
Although Shephard's original proof used the distance formula, modern proofs of Shephard's lemma use the envelope theorem.
Proof for the differentiable case
The proof is stated for the two-good case for ease of notation. The expenditure function is the value funct |
https://en.wikipedia.org/wiki/Plasmodium%20vivax | Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria. Although it is less virulent than Plasmodium falciparum, the deadliest of the five human malaria parasites, P. vivax malaria infections can lead to severe disease and death, often due to splenomegaly (a pathologically enlarged spleen). P. vivax is carried by the female Anopheles mosquito; the males do not bite.
Health
Epidemiology
Plasmodium vivax is found mainly in Asia, Latin America, and in some parts of Africa. P. vivax is believed to have originated in Asia, but recent studies have shown that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. These findings indicate that human P. vivax is of African origin. Plasmodium vivax accounts for 65% of malaria cases in Asia and South America. Unlike Plasmodium falciparum, Plasmodium vivax is capable of undergoing sporogonic development in the mosquito at lower temperatures. It has been estimated that 2.5 billion people are at risk of infection with this organism.
Although the Americas contribute 22% of the global area at risk, high endemic areas are generally sparsely populated and the region contributes only 6% to the total population at risk. In Africa, the widespread lack of the Duffy antigen in the population has ensured that stable transmission is constrained to Madagascar and parts of the Horn of Africa. It contributes 3.5% of global population at risk. Central Asia is responsible for 82% of global population at risk with high endemic areas coinciding with dense populations particularly in India and Myanmar. South East Asia has areas of high endemicity in Indonesia and Papua New Guinea and overall contributes 9% of global population at risk.
P. vivax is carried by at least 71 mosquito species. Many vivax vectors thrive in temperate climates—as far north as Finland. Some |
https://en.wikipedia.org/wiki/Bearer-Independent%20Call%20Control | The Bearer-Independent Call Control (BICC) is a signaling protocol based on N-ISUP that is used for supporting narrowband Integrated Services Digital Network (ISDN) service over a broadband backbone network. BICC is designed to interwork with existing transport technologies. BICC is specified in ITU-T recommendation Q.1901.
BICC signaling messages are nearly identical to those in ISDN User Part (ISUP); the main difference being that the narrowband circuit identification code (CIC) has been modified. The BICC architecture consists of interconnected serving nodes that provide the call service function and the bearer control function. The call service function uses BICC signaling for call setup and may also interwork with ISUP. The bearer control function receives directives from the call service function via BICC Bearer Control Protocol (ITU-T recommendation Q.1950) and is responsible for setup and teardown of bearer paths on a set of physical transport links. Transport links are most commonly Asynchronous Transfer Mode (ATM) or Internet Protocol (IP).
According to the ITU, the completion of the BICC protocols is a historic step toward broadband multimedia networks because it enables the seamless migration from circuit-switched TDM networks to high-capacity broadband multimedia networks.
The Third-Generation Partnership Project (3GPP) has included BICC CS 2 in the Universal Mobile Telecommunications System (UMTS) release 4. |
https://en.wikipedia.org/wiki/Butter%20Brickle | Butter Brickle is a chocolate-coated toffee first sold on November 20, 1924 by candy manufacturer John G. Woodward Co. of Council Bluffs, Iowa, and toffee pieces for flavoring ice cream, manufactured by The Fenn Bros. Ice Cream and Candy Co. of Sioux Falls, South Dakota.
John G. Woodward & Co.
Butter Brickle was first sold on 20 November 1924, and the trademark registered 15 May 1928 by candy manufacturer John G. Woodward Co. in Council Bluffs, Iowa for candy, not ice cream.
Arthur E. Dempsey, a candy maker and later, inventor, at John G. Woodward Co. in Council Bluffs, Iowa, reportedly, was the creator of the candy, trademarked as Butter Brickle
Fenn Bros. Ice Cream and Candy Co.
Fenn Bros. Ice Cream and Candy Co., founded in 1898, by Henry C. Fenn and James W. Fenn, is most known for its registered trademark chocolate-coated toffee, and toffee ice cream flavoring called Butter Brickle. The products were called Fenn's Butter Brickle English Toffee Chocolate Covered and Fenn's Butter Brickle Candy Ice Cream Flavoring.
Omaha, Nebraska's Blackstone Hotel's Orleans Room restaurant has been credited with creating Butter Brickle ice cream, in the late 1920s. Small pieces of the toffee candy bar were used, in effect, to make a mix-in, later sold as the product, Fenn's Butter Brickle Candy Ice Cream Flavoring.
Besides Butter Brickle, the company also made Walnut Crush, Blue Seal Nougat, Smooth Sailin’, Royal Brazils, and Big Bogie (later Big Nougat), and ice cream.
The first sponsored musical program on KSOO Radio was sponsored by Fenn's Blue Seal Nougat Bar.
The United States Food and Drug Administration cited them in 1940 for labeling and in 1947 for filthy product.
In the late 1950s and 1960s, Butter Brickle candy bars were advertised on radio and television with the slogan "Got a nickel? Butter Brickle,... candy bar!" delivered in an arch stage British accent.
At the company’s peak, more than 200 people worked at Fenn’s, making it one of Sioux Falls' larges |
https://en.wikipedia.org/wiki/Trichinella | Trichinella is the genus of parasitic roundworms of the phylum Nematoda that cause trichinosis (also known as trichinellosis). Members of this genus are often called trichinella or trichina worms. A characteristic of Nematoda is the one-way digestive tract, with a pseudocoelom (body cavity made up of only an ectoderm and endoderm).
The genus was first recognised in a larval form in 1835. The L1 larvae live in a modified skeletal muscle cell. The adult worms occupy a membrane-bound portion of columnar epithelium, living as intramulticellular parasites of animals, including humans. Infections with this genus have been reported from more than 150 different naturally or experimentally infected hosts. It has been shown to have a worldwide distribution in domestic and/or sylvatic animals.
Trichinella is the smallest human nematode parasite, yet it is also the largest of all intracellular parasites.
Oral ingestion of cyst- or larvae-contaminated tissue is the usual route of infection, but congenital and mammary transmission can occur in rats.
Phylogenetics
Eight species are currently recognized. Four additional genotypes require adequate description before they can be recognized as valid species.
Two main clades are recognized in the genus: one group (T. britovi, T. murrelli, T. nativa, T. nelsoni, T. spiralis) that encapsulates in host muscle tissue and a second (T. papuae, T. pseudospiralis, T. zimbabwensis) that does not.
The nonencapsulated group infects saurians, crocodilians, and other nonavian archosaurs (T. papuae, T. zimbabwensis) and birds (T. pseudospiralis). The encapsulated group infects synapsid and mammalian hosts. T. spiralis and T. nelsoni appear to be basal in the encapsulated group and T. murrelli and T. nativa the most recently evolved.
Prevalence in animals and humans
Trichinella species can infect swine, wild omnivores (foxes, wolves, bears, skunk, raccoons, rats, and other small mammals), and humans.
In swine, the prevalence varies from coun |
https://en.wikipedia.org/wiki/Matrix-assisted%20laser%20desorption/ionization | In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy-absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of biomolecules (biopolymers such as DNA, proteins, peptides and carbohydrates) and various organic molecules (such as polymers, dendrimers and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft (low fragmentation) ways of obtaining ions of large molecules in the gas phase, though MALDI typically produces far fewer multi-charged ions.
MALDI methodology is a three-step process. First, the sample is mixed with a suitable matrix material and applied to a metal plate. Second, a pulsed laser irradiates the sample, triggering ablation and desorption of the sample and matrix material. Finally, the analyte molecules are ionized by being protonated or deprotonated in the hot plume of ablated gases, and then they can be accelerated into whichever mass spectrometer is used to analyse them.
History
The term matrix-assisted laser desorption ionization (MALDI) was coined in 1985 by Franz Hillenkamp, Michael Karas and their colleagues. These researchers found that the amino acid alanine could be ionized more easily if it was mixed with the amino acid tryptophan and irradiated with a pulsed 266 nm laser. The tryptophan was absorbing the laser energy and helping to ionize the non-absorbing alanine. Peptides up to the 2843 Da peptide melittin could be ionized when mixed with this kind of "matrix". The breakthrough for large molecule laser desorption ionization came in 1987 when Koichi Tanaka of Shimadzu Corporation and his co-workers used what they called the "ultra fine metal plus liquid matrix method" that combined 30 nm cobalt particles in glycerol with a 337 nm nitrogen la |
https://en.wikipedia.org/wiki/Nurse%20cell | In general biology or reproductive physiology, a nurse cell is a cell which provides food, helps other cells and provides stability to neighboring cells. The term nurse cell is used in several unrelated ways in different scientific fields.
Human physiology
Nurse cells are specialized macrophages residing in the bone marrow that assist in the development of red blood cells. They absorb the nuclei of immature red blood cells and may provide growth factors to help the red blood cells mature. In the bone marrow, immature red blood cells (erythroblasts) can be seen grouped in a cluster around a nurse cell.
The epithelial cell found in the cortex of the thymus is also called a "nurse cell." These cells produce Thymic hormones that cause T lymphocytes to mature and differentiate.
Parasitology
In parasitology, a nurse cell is an infected cell in the disease trichinosis discovered by Dickson Despommier. A trichinella larva enters a cell and develops there, probably as a way of concealing itself from the immune system. The parasite has evolved a way of stimulating blood vessel development around the cell, in order to receive the nutrients it needs. In trichinosis, nurse cells are invariably skeletal muscle cells; these are the only type of cell that can support the parasite.
Mycology
In mycology, a nurse cell is any hyphae that supplies food material to spores that have detached from the basidia; used especially in reference to taxa from the family Sclerodermataceae.
Cell biology
In respect to invertebrates, nurse cells are polytenic germline cells that contribute to the development of the oocyte, producing multiple nuclei. In fruit flies (Drosophila), nurse cells surround the developing oocyte and synthesize proteins and RNAs that are to be deposited in it. Nurse cells are highly polyploid (up to 8000C). They dump their cytoplasm containing RNAs and proteins into the oocyte via ring canals.
Due to their high metabolic activity, nurse cells likely experience the DNA |
https://en.wikipedia.org/wiki/Tree%20%28descriptive%20set%20theory%29 | In descriptive set theory, a tree on a set is a collection of finite sequences of elements of such that every prefix of a sequence in the collection also belongs to the collection.
Definitions
Trees
The collection of all finite sequences of elements of a set is denoted .
With this notation, a tree is a nonempty subset of , such that if
is a sequence of length in , and if ,
then the shortened sequence also belongs to . In particular, choosing shows that the empty sequence belongs to every tree.
Branches and bodies
A branch through a tree is an infinite sequence of elements of , each of whose finite prefixes belongs to . The set of all branches through is denoted and called the body of the tree .
A tree that has no branches is called wellfounded; a tree with at least one branch is illfounded. By Kőnig's lemma, a tree on a finite set with an infinite number of sequences must necessarily be illfounded.
Terminal nodes
A finite sequence that belongs to a tree is called a terminal node if it is not a prefix of a longer sequence in . Equivalently, is terminal if there is no element of such that that . A tree that does not have any terminal nodes is called pruned.
Relation to other types of trees
In graph theory, a rooted tree is a directed graph in which every vertex except for a special root vertex has exactly one outgoing edge, and in which the path formed by following these edges from any vertex eventually leads to the root vertex.
If is a tree in the descriptive set theory sense, then it corresponds to a graph with one vertex for each sequence in , and an outgoing edge from each nonempty sequence that connects it to the shorter sequence formed by removing its last element. This graph is a tree in the graph-theoretic sense. The root of the tree is the empty sequence.
In order theory, a different notion of a tree is used: an order-theoretic tree is a partially ordered set with one minimal element in which each element has a well-ordered set of pre |
https://en.wikipedia.org/wiki/Artificial%20digestion | Artificial digestion is a laboratory technique that reduces food to protein, fat, carbohydrates, fiber, minerals, vitamins, and non-nutrient compounds for analytical or research purposes. Digestive agents such as pepsin and hydrochloric acid are typically used to accomplish artificial digestion.
Meat inspection
Artificial digestion is used to detect the presence of encysted trichinella larvae in suspected muscle tissue. Prior to this method, a sample of muscle tissue was compressed to visually express the encysted parasite. Using artificial digestion, meat samples are dissolved by a digestive solution and the remains are examined for the presence of larvae.
Digestion research
Artificial stomach and small intestine models are used instead of laboratory animals or human test subjects. Various models, from static one-compartment to dynamic multicompartment, exist. These models are used to study food digestion and subsequent bioavailability. |
https://en.wikipedia.org/wiki/Internal%20set | In mathematical logic, in particular in model theory and nonstandard analysis, an internal set is a set that is a member of a model.
The concept of internal sets is a tool in formulating the transfer principle, which concerns the logical relation between the properties of the real numbers R, and the properties of a larger field denoted *R called the hyperreal numbers. The field *R includes, in particular, infinitesimal ("infinitely small") numbers, providing a rigorous mathematical justification for their use. Roughly speaking, the idea is to express analysis over R in a suitable language of mathematical logic, and then point out that this language applies equally well to *R. This turns out to be possible because at the set-theoretic level, the propositions in such a language are interpreted to apply only to internal sets rather than to all sets (note that the term "language" is used in a loose sense in the above).
Edward Nelson's internal set theory is an axiomatic approach to nonstandard analysis (see also Palmgren at constructive nonstandard analysis). Conventional infinitary accounts of nonstandard analysis also use the concept of internal sets.
Internal sets in the ultrapower construction
Relative to the ultrapower construction of the hyperreal numbers as equivalence classes of sequences of reals, an internal subset [An] of *R is one defined by a sequence of real sets , where a hyperreal is said to belong to the set if and only if the set of indices n such that , is a member of the ultrafilter used in the construction of *R.
More generally, an internal entity is a member of the natural extension of a real entity. Thus, every element of *R is internal; a subset of *R is internal if and only if it is a member of the natural extension of the power set of R; etc.
Internal subsets of the reals
Every internal subset of *R that is a subset of (the embedded copy of) R is necessarily finite (see Theorem 3.9.1 Goldblatt, 1998). In other words, every inter |
https://en.wikipedia.org/wiki/International%20Conference%20on%20Photonic%2C%20Electronic%20and%20Atomic%20Collisions | ICPEAC, the International Conference on Photonic, Electronic and Atomic Collisions, is a biennial scientific conference. It is held in late July. The first conference was held in New York City in 1958. Since then it has been held in the following locations: |
https://en.wikipedia.org/wiki/Prenatal%20development | Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal development until birth.
In human pregnancy, prenatal development is also called antenatal development. The development of the human embryo follows fertilization, and continues as fetal development. By the end of the tenth week of gestational age the embryo has acquired its basic form and is referred to as a fetus. The next period is that of fetal development where many organs become fully developed. This fetal period is described both topically (by organ) and chronologically (by time) with major occurrences being listed by gestational age.
The very early stages of embryonic development are the same in all mammals, but later stages of development, and the length of gestation varies.
Terminology
In the human:
Different terms are used to describe prenatal development, meaning development before birth. A term with the same meaning is the "antepartum" (from Latin ante "before" and parere "to give birth") Sometimes "antepartum" is however used to denote the period between the 24th/26th week of gestational age until birth, for example in antepartum hemorrhage.
The perinatal period (from Greek peri, "about, around" and Latin nasci "to be born") is "around the time of birth". In developed countries and at facilities where expert neonatal care is available, it is considered from 22 completed weeks (usually about 154 days) of gestation (the time when birth weight is normally 500 g) to 7 completed days after birth. In many of the developing countries the starting point of this period is considered 28 completed weeks of gestation (or weight more than 1000 g).
Fertilization
Fertilization marks the first germinal stage of embryonic development. When semen is released into the vagina, the spermatozoa travel through the cervix, along the bo |
https://en.wikipedia.org/wiki/Post-perovskite | Post-perovskite (pPv) is a high-pressure phase of magnesium silicate (MgSiO3). It is composed of the prime oxide constituents of the Earth's rocky mantle (MgO and SiO2), and its pressure and temperature for stability imply that it is likely to occur in portions of the lowermost few hundred km of Earth's mantle.
The post-perovskite phase has implications for the D′′ layer, which influences the convective mixing in the mantle responsible for plate tectonics.
Post-perovskite has the same crystal structure as the synthetic solid compound CaIrO3, and is often referred to as the "CaIrO3-type phase of MgSiO3" in the literature. The crystal system of post-perovskite is orthorhombic, its space group is Cmcm, and its structure is a stacked SiO6-octahedral sheet along the b axis. The name "post-perovskite" derives from silicate perovskite, the stable phase of MgSiO3 throughout most of Earth's mantle, which has the perovskite structure. The prefix "post-" refers to the fact that it occurs after perovskite structured MgSiO3 as pressure increases (and historically, the progression of high pressure mineral physics). At upper mantle pressures, nearest Earth's surface, MgSiO3 persists as the silicate mineral enstatite, a pyroxene rock forming mineral found in igneous and metamorphic rocks of the crust.
History
The CaIrO3-type phase of MgSiO3 phase was discovered in 2004 using the laser-heated diamond anvil cell (LHDAC) technique by a group at the Tokyo Institute of Technology and, independently, by researchers from the Swiss Federal Institute of Technology (ETH Zurich) and Japan Agency for Marine-Earth Science and Technology who used a combination of quantum-mechanical simulations and LHDAC experiments. The TIT group's paper appeared in the journal Science. The ETH/JAM-EST collaborative paper and TIT group's second paper appeared two months later in the journal Nature. This simultaneous discovery was preceded by S. Ono's experimental discovery of a similar phase, possessing exac |
https://en.wikipedia.org/wiki/Forward%20secrecy | In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key-agreement protocols that gives assurances that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised. For HTTPS, the long-term secret is typically the private key of the server. Forward secrecy protects past sessions against future compromises of keys or passwords. By generating a unique session key for every session a user initiates, the compromise of a single session key will not affect any data other than that exchanged in the specific session protected by that particular key. This by itself is not sufficient for forward secrecy which additionally requires that a long-term secret compromise does not affect the security of past session keys.
Forward secrecy protects data on the transport layer of a network that uses common transport layer security protocols, including OpenSSL, when its long-term secret keys are compromised, as with the Heartbleed security bug. If forward secrecy is used, encrypted communications and sessions recorded in the past cannot be retrieved and decrypted should long-term secret keys or passwords be compromised in the future, even if the adversary actively interfered, for example via a man-in-the-middle (MITM) attack.
The value of forward secrecy is that it protects past communication. This reduces the motivation for attackers to compromise keys. For instance, if an attacker learns a long-term key, but the compromise is detected and the long-term key is revoked and updated, relatively little information is leaked in a forward secure system.
The value of forward secrecy depends on the assumed capabilities of an adversary. Forward secrecy has value if an adversary is assumed to be able to obtain secret keys from a device (read access) but is either detected or unable to modify the way session keys are generated in the device (full compromise). In some cases an adversary |
https://en.wikipedia.org/wiki/Neutron%20cross%20section | In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of neutron-nuclei reactions taking place is equal to the product of the number of incident neutrons that would pass through the area and the number of target nuclei. In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power of a nuclear power plant. The standard unit for measuring the cross section is the barn, which is equal to 10−28 m2 or 10−24 cm2. The larger the neutron cross section, the more likely a neutron will react with the nucleus.
An isotope (or nuclide) can be classified according to its neutron cross section and how it reacts to an incident neutron. Nuclides that tend to absorb a neutron and either decay or keep the neutron in its nucleus are neutron absorbers and will have a capture cross section for that reaction. Isotopes that undergo fission are fissionable fuels and have a corresponding fission cross section. The remaining isotopes will simply scatter the neutron, and have a scatter cross section. Some isotopes, like uranium-238, have nonzero cross sections of all three.
Isotopes which have a large scatter cross section and a low mass are good neutron moderators (see chart below). Nuclides which have a large absorption cross section are neutron poisons if they are neither fissile nor undergo decay. A poison that is purposely inserted into a nuclear reactor for controlling its reactivity in the long term and improve its shutdown margin is called a burnable poison.
Parameters of interest
The neutron cross section, and therefore the probability of an neutron-nucleus interaction, depends on:
the target type (hydrogen, uranium…),
the type of nuclear reaction (scattering, fission…).
the incident particle energy, also called speed or temperatur |
https://en.wikipedia.org/wiki/Chinese%20numerology | Some numbers are believed by some to be auspicious or lucky (吉利, ) or inauspicious or unlucky (不吉, ) based on the Chinese word that the number sounds similar to. The numbers 2, 3, 6, and 8 are generally considered to be lucky, while 4 is considered unlucky. These traditions are not unique to Chinese culture, with other countries with a history of Han characters also having similar beliefs stemming from these concepts.
Zero
The number 0 (零, ) is the beginning of all things and is generally considered a good number, because it sounds like 良 (pinyin: liáng), which means 'good'.
One
The number 1 (一, ) is neither auspicious nor inauspicious. It is a number given to winners to indicate the first place. But it can also symbolize loneliness or being single. For example: November 11 is the Singles' Day in China, as the date has four ‘1’ which stand for singles.
Two
The number 2 (二, cardinal, or 兩, used with units, ) is most often considered a good number in Chinese culture. In Cantonese, 2 (二 or 兩, ) is homophonous with the characters for "easy" (易, ) and "bright" (亮, ), respectively. There is a Chinese saying: "good things come in pairs". It is common to repeat characters in product brand names, such as the character 喜 (), can be repeated to form the character 囍 ().
24 () in Cantonese sounds like "easy die" (易死, ).
28 () in Cantonese sounds like "easy prosper" (易發, ).
Three
The number 3 (三, ) sounds like 生 (), which means "to live" or "life" so it's considered a good number. It's significant since it is one of three important stages in a person's life (birth, marriage, and death).On the other hand, number 3 (三,) sounds like 散 () which means "to split" or "to separate" or "to part ways" or "to break up with" so it is a bad number too.
Four
While not traditionally considered an unlucky number, 4 has in recent times, gained an association with bad luck because of its pronunciation, predominantly for the Cantonese.
The belief that the number 4 is unlucky originated |
https://en.wikipedia.org/wiki/WPFO | WPFO (channel 23) is a television station licensed to Waterville, Maine, United States, serving the Portland area as an affiliate of the Fox network. It is owned by Cunningham Broadcasting, which maintains a local marketing agreement (LMA) with Sinclair Broadcast Group, owner of CBS affiliate WGME-TV (channel 13), for the provision of certain services. However, Sinclair effectively owns WPFO as the majority of Cunningham's stock is owned by the family of deceased group founder Julian Smith. The stations share studios on Northport Drive in the North Deering section of Portland, while WPFO's transmitter is located on Brown Hill west of Raymond.
History
The station began broadcasting on August 27, 1999, as WMPX-TV and was a Pax TV (now Ion Television) affiliate owned by Paxson Communications (now Ion Media Networks). In addition to Pax programming, WMPX carried a small amount of local programming and in 2001, the station began airing rebroadcasts of NBC affiliate WCSH (channel 6)'s 11 p.m. newscasts when NBC had a partnership with Pax. Paxson sold the station in December 2002 to Corporate Media Consultants Group who changed the call sign to the current WPFO. The new calls reflected an affiliation change to Fox, which took place on April 7, 2003, filling a gap created in fall 2001 when WPXT (channel 51) switched to The WB. In the interim, prime time and children's programming from the Fox network was provided exclusively on WFXT (which was owned by the network at the time) for those living on the New Hampshire side of the market, and on Foxnet for cable subscribers throughout the entire state of Maine; WCKD-LP served as a secondary affiliate of Fox during that time, but only carried the network's sports programming. In July 2007, WPFO debuted a new logo and updated website. The website's design was outsourced to Fox Interactive Media which also develops websites for Fox's owned-and-operated stations. WPFO switched website providers to Broadcast Interactive Media in Ma |
https://en.wikipedia.org/wiki/Joseph%20Weber | Joseph Weber (May 17, 1919 – September 30, 2000) was an American physicist. He gave the earliest public lecture on the principles behind the laser and the maser and developed the first gravitational wave detectors (Weber bars).
Early life
Joseph Weber was born in Paterson, New Jersey, on 17 May 1919, the last of four children born to Yiddish-speaking immigrant parents. His name was "Yonah" until he entered grammar school. He had no birth certificate, and his father had taken the last name of "Weber" to match an available passport in order to emigrate to the US. Thus, Joe Weber had little proof of either his family or his given name, which gave him some trouble in obtaining a passport at the height of the red scare.
Early education
Weber attended Paterson public schools (and the Paterson Talmud Torah), graduating at sixteen from the "Mechanic Arts Course" of Paterson Eastside High School in June 1935. He began his undergraduate education at Cooper Union, but to save his family the expense of his room and board he won admittance to the United States Naval Academy through a competitive exam. He graduated from the Academy in 1940.
Naval career
He served aboard US Navy ships during World War II, rising to the rank of lieutenant commander. Weber was the Officer of the Deck on the USS Lexington when the ship received word of the attack on Pearl Harbor. In the Battle of the Coral Sea his carrier sank the Japanese aircraft carrier Shōhō and was in turn mortally damaged on May 8, 1942. Weber often regaled his students with the story of how the Lexington glowed incandescent as she slipped beneath the waves.
Later, he commanded the sub-chaser SC-690, first in the Caribbean, and later in the Mediterranean Sea. In that role, he took part in the invasion of Sicily at Gela Beach, in July 1943.
He studied electronics at the Naval Postgraduate School in 1943-45, and from 1945 to 1948, he headed electronic countermeasures design for the Navy's Bureau of Ships, in Washington, DC. |
https://en.wikipedia.org/wiki/Atomix%20%28video%20game%29 | Atomix is a puzzle video game developed by Günter Krämer (as "Softtouch") and published by Thalion Software, released for the Amiga and other personal computers in late 1990. The object of the game is to assemble molecules from compound atoms by moving the atoms on a two-dimensional playfield.
Atomix was received positively; reviewers noted the game's addictiveness and enjoyable gameplay, though criticized its repetitiveness.
Gameplay
Atomix takes place on a playfield consisting of a number of walls, with the atoms scattered throughout. The player is tasked with assembling a molecule from the atoms. The atoms must be arranged to exactly match the molecule displayed on the left side of the screen. The player can choose an atom and move it in any of the four cardinal directions. A moved atom keeps sliding in one direction until it hits a wall or another atom. Solving the puzzles requires strategic planning in moving the atoms, and on later levels with little free space, even finding room for the completed molecule can be a problem. Once the molecule is assembled, the player is given a score; the faster the puzzle was completed, the higher the score.
Each puzzle must be completed within a time limit. A portion of the player's score can be spent to restart a failed puzzle. The entire game consists of 30 puzzles of increasing difficulty. In addition, after every five puzzles, there is a bonus level where the player must move laboratory flasks filled with various amounts of liquid to arrange them from empty to full.
The game also offers a two-player mode, where two players work on the same puzzle; they take turns which last up to thirty seconds.
Development
Amiga Format reviewed a pre-release version in its May, 1990 issue. It was almost a complete version of the game although it lacked sound.
Initially the game was released for Amiga, Atari ST and the IBM PC; as of May 1990, the C64 version was not yet planned, and was only released a few months later. A ZX Spect |
https://en.wikipedia.org/wiki/CPU%20core%20voltage | The CPU core voltage (VCORE) is the power supply voltage supplied to the CPU (which is a digital circuit), GPU, or other device containing a processing core. The amount of power a CPU uses, and thus the amount of heat it dissipates, is the product of this voltage and the current it draws.
In modern CPUs, which are CMOS circuits, the current is almost proportional to the clock speed, the CPU drawing almost no current between clock cycles. (See, however, subthreshold leakage.)
Power saving and clock speed
To conserve power and manage heat, many laptop and desktop processors have a power management feature that software (usually the operating system) can use to adjust the clock speed and core voltage dynamically.
Often a voltage regulator module converts from 5V or 12 V or some other voltage to whatever CPU core voltage is required by the CPU.
The trend is towards lower core voltages, which conserve power. This presents the CMOS designer with a challenge, because in CMOS the voltages go only to ground and the supply voltage, the source, gate, and drain terminals of the FETs have only the supply voltage or zero voltage across them.
The MOSFET formula: says that the current supplied by the FET is proportional to the gate-source voltage reduced by a threshold voltage , which depends on the geometrical shape of the FET's channel and gate and their physical properties, especially capacitance. To reduce (necessary to reduce supply voltage and increase current) one must increase capacitance. However, the load being driven is another FET gate, so the current it requires is proportional to capacitance, which thus requires the designer to keep capacitance low.
The trend towards lower supply voltage therefore works against the goal of high clock speed.
Only improvements in photolithography and reduction in threshold voltage allow both to improve at once. On another note, the formula shown above is for long channel MOSFETs. With the area of the MOSFETs halving every |
https://en.wikipedia.org/wiki/CAVNET | CAVNET was a secure military forum which became operational in April 2004. A part of SIPRNet, it allows fast access to knowledge acquired on the ground in combat.
It was used in Iraq war, and helps US military forces against the insurgents' adaptive tactics by providing data laterally and on a broader scale than with traditional reports.
The data shared between patrols on "The Net" (as is it is sometimes referred to by soldiers) has already played a crucial role to dismantle grenade-traps hidden behind posters of Moqtada al-Sadr that US soldiers often rip down. |
https://en.wikipedia.org/wiki/RAYDAC | The RAYDAC (for Raytheon Digital Automatic Computer) was a one-of-a-kind computer built by Raytheon. It was started in 1949 and finished in 1953. It was installed at the Naval Air Missile Test Center at Point Mugu, California.
The RAYDAC used 5,200 vacuum tubes and 18,000 crystal diodes. It had 1,152 words of memory (36 bits per word), using delay-line memory, with an access time of up to 305 microseconds. Its addition time was 38 microseconds, multiplication time was 240 microseconds, and division time was 375 microseconds. (These times exclude the memory-access time.)
See also
List of vacuum-tube computers
External links
Erwin Tomash photo of General Front View From Right Side of RAYDAC Test Control Board (image)
Erwin Tomash drawing of RADAC Computer Control Room Showing Main Computer and Operator's Console (image) |
https://en.wikipedia.org/wiki/Dihydrogen%20bond | In chemistry, a dihydrogen bond is a kind of hydrogen bond, an interaction between a metal hydride bond and an OH or NH group or other proton donor. With a van der Waals radius of 1.2 Å, hydrogen atoms do not usually approach other hydrogen atoms closer than 2.4 Å. Close approaches near 1.8 Å, are, however, characteristic of dihydrogen bonding.
Boron hydrides
An early example of this phenomenon is credited to Brown and Heseltine. They observed intense absorptions in the IR bands at 3300 and 3210 cm−1 for a solution of (CH3)2NHBH3. The higher energy band is assigned to a normal N−H vibration whereas the lower energy band is assigned to the same bond, which is interacting with the B−H. Upon dilution of the solution, the 3300 cm−1 band increased in intensity and the 3210 cm−1 band decreased, indicative of intermolecular association.
Interest in dihydrogen bonding was reignited upon the crystallographic characterization of the molecule H3NBH3. In this molecule, like the one studied by Brown and Hazeltine, the hydrogen atoms on nitrogen have a partial positive charge, denoted Hδ+, and the hydrogen atoms on boron have a partial negative charge, often denoted Hδ−. In other words, the amine is a protic acid and the borane end is hydridic. The resulting B−H...H−N attractions stabilize the molecule as a solid. In contrast, the related substance ethane, H3CCH3, is a gas with a boiling point 285 °C lower. Because two hydrogen centers are involved, the interaction is termed a dihydrogen bond. Formation of a dihydrogen bond is assumed to precede formation of H2 from the reaction of a hydride and a protic acid. A very short dihydrogen bond is observed in NaBH4·2H2O with H−H contacts of 1.79, 1.86, and 1.94 Å.
Coordination chemistry
Protonation of transition metal hydride complexes is generally thought to occur via dihydrogen bonding. This kind of H−H interaction is distinct from the H−H bonding interaction in transition metal complexes having dihydrogen bound to a meta |
https://en.wikipedia.org/wiki/Voodoo%20doll | The term Voodoo doll commonly refers to an effigy that is typically used for the insertion of pins. Such practices are found in various forms in the magical traditions of many cultures around the world.
Despite its name, the dolls are not prominent in Haitian Vodou and not used in Louisiana Voodoo.
The practice has been denounced and declared irrelevant to Voodoo religion by those in High Priesthood of Louisiana Voodoo.
Depictions in culture
20th-century link with Voodoo
The link between this magical practice and Voodoo was established through the presentation of the latter in Western popular culture, enduring the first half of the 20th century. In this, the myth of this magical practice being closely linked to Voodoo and Vodou was promoted as part of the wider negative depictions of blacks and Afro-Caribbean religious practices in the United States. In John Houston Craige's 1933 book Black Bagdad: The Arabian Nights Adventures of a Marine Captain in Haiti, he described a Haitian prisoner sticking pins into an effigy to induce illness. Its use also appeared in film representations of Haitian Vodou such as Victor Halperin's 1932 White Zombie and Jacques Tourneur’s 1943 I Walked with a Zombie. Voodoo dolls are also featured in one episode of The Woody Woodpecker Show (1961), as well as in the British musical Lisztomania (1975) and the films Indiana Jones and the Temple of Doom (1984), The Witches of Eastwick (1987) and Scooby-Doo on Zombie Island (1998).
By the early 21st century, the image of the voodoo doll had become particularly pervasive. It had become a novelty item available for purchase, with examples being provided in vending machines in British shopping centres, and an article on "How to Make a Voodoo Doll" being included on WikiHow. Voodoo dolls were also featured in the 2009 animated Disney movie The Princess and the Frog, as well as the 2011 live-action Disney movie Pirates of the Caribbean: On Stranger Tides.
In 2020, Louisiana Voodoo High Priest |
https://en.wikipedia.org/wiki/Guillemet | Guillemets (, also , , ) are a pair of punctuation marks in the form of sideways double chevrons, and , used as quotation marks in a number of languages. In some of these languages, "single" guillemets, and , are used for a quotation inside another quotation. Guillemets are not conventionally used in the English language.
Terminology
Guillemets may also be called angle, Latin, Castilian, Spanish, or French quotes / quotation marks.
Guillemet is a diminutive of the French name , apparently after the French printer and punchcutter Guillaume Le Bé (1525–1598), though he did not invent the symbols: they first appear in a 1527 book printed by Josse Bade. Some languages derive their word for guillemets analogously:
In Adobe Systems font software, its file format specifications, and in all fonts derived from these that contain the characters, the glyph names are incorrectly spelled and (a malapropism: guillemot is actually a species of seabird). Adobe acknowledges the error. Likewise, X11 mistakenly uses and to name keys producing the characters.
Shape
Guillemets are smaller than less-than and greater-than signs, which in turn are smaller than angle brackets.
Uses
As quotation marks
Guillemets are used pointing outwards («like this») to indicate speech in these languages and regions:
Albanian
Arabic
Armenian
Belarusian
Breton
Bulgarian (rarely used; „...“ is official)
Catalan
Chinese (《 and 》 are used to indicate a book or album title)
Esperanto (usage varies)
Estonian (marked usage; „...“ prevails)
Franco-Provençal
French (spaced out by thin spaces « like this », except in Switzerland)
Galician
Greek
Italian
Khmer
Northern Korean (in Southern Korean, " is used)
Kurdish
Latvian (stūrainās pēdiņas)
Norwegian
Persian
Portuguese (used mostly in European Portuguese, due to its presence in typical computer keyboards; considered obsolete in Brazilian Portuguese)
Romanian; only to indicate a quotation within a quotation
Russian, and some |
https://en.wikipedia.org/wiki/LDAP%20Data%20Interchange%20Format | The LDAP Data Interchange Format (LDIF) is a standard plain text data interchange format for representing Lightweight Directory Access Protocol (LDAP) directory content and update requests. LDIF conveys directory content as a set of records, one record for each object (or entry). It also represents update requests, such as Add, Modify, Delete, and Rename, as a set of records, one record for each update request.
LDIF was designed in the early 1990s by Tim Howes, Mark C. Smith, and Gordon Good while at the University of Michigan. LDIF was updated and extended in the late 1990s for use with Version 3 of LDAP. This later version of LDIF is called version 1 and is formally specified in RFC 2849, an IETF Standard Track RFC. RFC 2849 is authored by Gordon Good and was published in June 2000. It is currently a Proposed Standard.
A number of extensions to LDIF have been proposed over the years. One extension has been formally specified by the IETF and published. RFC 4525, authored by Kurt Zeilenga, extended LDIF to support the LDAP Modify-Increment extension. It is expected that additional extensions will be published by the IETF in the future.
Content record format
Each content record is represented as a group of attributes, with records separated from one another by blank lines. The individual attributes of a record are represented as single logical lines (represented as one or more multiple physical lines via a line-folding mechanism), comprising "name: value" pairs. Value data that do not fit within a portable subset of ASCII characters are marked with '::' after the attribute name and encoded into ASCII using base64 encoding. The content record format is a subset of the Internet Directory Information type.RFC 2425
Tools that employ LDIF
The OpenLDAP utilities include tools for exporting data from LDAP servers to LDIF content records (), importing data from LDIF content records to LDAP servers (), and applying LDIF change records to LDAP servers ().
LDI |
https://en.wikipedia.org/wiki/Fungiculture | Fungiculture is the cultivation of fungi such as mushrooms. Cultivating fungi can yield foods (which include mostly mushrooms), medicine, construction materials and other products. A mushroom farm is involved in the business of growing fungi.
The word is also commonly used to refer to the practice of cultivation of fungi by animals such as leafcutter ants, termites, ambrosia beetles, and marsh periwinkles.
Overview
Mushrooms are fungi and require different conditions than plants for optimal growth. Plants develop through photosynthesis, a process that converts atmospheric carbon dioxide into carbohydrates, especially cellulose. While sunlight provides an energy source for plants, mushrooms derive all of their energy and growth materials from their growth medium, through biochemical decomposition processes. This does not mean that light is an irrelevant requirement, since some fungi use light as a signal for fruiting. However, all the materials for growth must already be present in the growth medium. Mushrooms grow well at relative humidity levels of around 95–100%, and substrate moisture levels of 50 to 75%.
Instead of seeds, mushrooms reproduce through spores. Spores can be contaminated with airborne microorganisms, which will interfere with mushroom growth and prevent a healthy crop.
Mycelium, or actively growing mushroom culture, is placed on a substrate—usually sterilized grains such as rye or millet—and induced to grow into those grains. This is called inoculation. Inoculated grains (or plugs) are referred to as spawn. Spores are another inoculation option, but are less developed than established mycelium. Since they are also contaminated easily, they are only manipulated in laboratory conditions with a laminar flow cabinet.
Techniques
All mushroom growing techniques require the correct combination of humidity, temperature, substrate (growth medium) and inoculum (spawn or starter culture). Wild harvests, outdoor log inoculation and indoor trays all provi |
https://en.wikipedia.org/wiki/Channel%20spacing | Channel spacing, also known as bandwidth, is a term used in radio frequency planning. It describes the frequency difference between adjacent allocations in a frequency plan. Channels for mediumwave radio stations, for example are allocated in internationally agreed steps of 9 or 10 kHz: 10 kHz in ITU Region 2 (the Americas), and 9 kHz elsewhere in the world. |
https://en.wikipedia.org/wiki/Whitehall%20Study | The Whitehall Studies investigated social determinants of health, specifically the cardiovascular disease prevalence and mortality rates among British civil servants. The initial prospective cohort study, the Whitehall I Study, examined over 17,500 male civil servants between the ages of 20 and 64, and was conducted over a period of ten years, beginning in 1967. A second cohort study, the Whitehall II Study, was conducted from 1985 to 1988 and examined the health of 10,308 civil servants aged 35 to 55, of whom two thirds were men and one third women. A long-term follow-up of study subjects from the first two phases is ongoing.
The studies, named after the Whitehall area of London and originally led by Michael Marmot, found a strong association between grade levels of civil servant employment and mortality rates from a range of causes: the lower the grade, the higher the mortality rate. Men in the lowest grade (messengers, doorkeepers, etc.) had a mortality rate three times higher than that of men in the highest grade (administrators). This effect has since been observed in other studies and named the "status syndrome".
Whitehall I
The first Whitehall Study compared mortality of people in the highly stratified environment of the British Civil Service. It showed that among British civil servants, mortality was higher among those in the lower grade when compared to the higher grade. The more senior one was in the employment hierarchy, the longer one might expect to live compared to people in lower employment grades.
The first of the Whitehall studies, or Whitehall I, found higher mortality rates due to all causes for men of lower employment grade. The study also revealed a higher mortality rate specifically due to coronary heart disease for men in the lower employment grade when compared to men in higher grades.
The initial Whitehall study found lower grades, and thus status, were clearly associated with higher prevalence of significant risk factors. These risk |
https://en.wikipedia.org/wiki/Headphone%20amplifier | A headphone amplifier is a low-powered audio amplifier designed particularly to drive headphones worn on or in the ears, instead of loudspeakers in speaker enclosures. Most commonly, headphone amplifiers are found embedded in electronic devices that have a headphone jack, such as integrated amplifiers, portable music players (e.g., iPods), and televisions. However, standalone units are used, especially in audiophile markets and in professional audio applications, such as music studios. Headphone amplifiers are available in consumer-grade models used by hi-fi enthusiasts and audiophiles and professional audio models, which are used in recording studios.
Consumer models
Consumer headphone amplifiers are commercially available separate devices, sold to a niche audiophile market of hi-fi enthusiasts. These devices allow for higher possible volumes and superior current capacity compared to the smaller, less expensive headphone amplifiers that are used in most audio players. In the case of the extremely high-end electrostatic headphones, such as the Stax SR-007, a specialized electrostatic headphone amplifier or transformer step-up box and power amplifier is required to use the headphones, as only a dedicated electrostatic headphone amplifier or transformer can provide the voltage levels necessary to drive the headphones. Most headphone amplifiers provide power between 10 mW and 2 W depending on the specific headphone being used and the design of the amplifier. Certain high power designs can provide up to 6W of power into low impedance loads, although the benefit of such power output with headphones is unclear, as the few orthodynamic headphones that have sufficiently low sensitivities to function with such power levels will reach dangerously high volume levels with such amplifiers.
Effectively, a headphone amplifier is a small power amplifier that can be connected to a standard headphone jack or the line output of an audio source. Electrically, a headphone amplifier |
https://en.wikipedia.org/wiki/Invention%20of%20the%20telephone | The invention of the telephone was the culmination of work done by more than one individual, and led to an array of lawsuits relating to the patent claims of several individuals and numerous companies.
Early development
The concept of the telephone dates back to the string telephone or lover's telephone that has been known for centuries, comprising two diaphragms connected by a taut string or wire. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone, a children's toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy was that a diaphragm can collect voice sounds from the voice sounds for reproduction at a distance. One precursor to the development of the electromagnetic telephone originated in 1833 when Carl Friedrich Gauss and Wilhelm Eduard Weber invented an electromagnetic device for the transmission of telegraphic signals at the University of Göttingen, in Lower Saxony, helping to create the fundamental basis for the technology that was later used in similar telecommunication devices. Gauss's and Weber's invention is purported to be the world's first electromagnetic telegraph.
Charles Grafton Page
In 1840, American Charles Grafton Page passed an electric current through a coil of wire placed between the poles of a horseshoe magnet. He observed that connecting and disconnecting the current caused a ringing sound in the magnet. He called this effect "galvanic music".
Innocenzo Manzetti
Innocenzo Manzetti considered the idea of a telephone as early as 1844, and may have made one in 1864, as an enhancement to an automaton built by him in 1849.
Charles Bourseul was a French telegraph engineer who proposed (but did not build) the first design of a "make-and-break" telephone in 1854. That is about the same time that Meucci later claimed to have created his first attempt at the |
https://en.wikipedia.org/wiki/Buffer%20credits | Buffer credits, also called buffer-to-buffer credits (BBC) are used as a flow control method by Fibre Channel technology and represent the number of frames a port can store.
Each time a port transmits a frame that port's BB Credit is decremented by one; for each R_RDY received, that port's BB Credit is incremented by one. If the BB Credit is zero the corresponding node cannot transmit until an R_RDY is received back.
The benefits of a large data buffer are particularly evident in long-distance applications, when operating at higher data rates (2 Gbit/s, 4 Gbit/s), or in systems with a heavily loaded PCI bus.
See also
Fibre Channel
Host adapter
Fibre Channel |
https://en.wikipedia.org/wiki/Thistle | Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. These prickles are an adaptation that protects the plant from being eaten by herbivores. Typically, an involucre with a clasping shape similar to a cup or urn subtends each of a thistle's flower heads. The typically feathery pappus of a ripe thistle flower is known as thistle-down.
The comparative amount of spininess varies dramatically by species. For example, Cirsium heterophyllum has minimal spininess while Cirsium spinosissimum is the opposite. Typically, species adapted to dry environments have greater spininess.
The term thistle is sometimes taken to mean precisely those plants in the tribe Cardueae (synonym: Cynareae), especially the genera Carduus, Cirsium, and Onopordum. However, plants outside this tribe are sometimes called thistles.
Biennial thistles are particularly noteworthy for their high wildlife value, producing such things as copious floral resources for pollinators, nourishing seeds for birds like the goldfinch, foliage for butterfly larvae, and down for the lining of birds' nests.
A thistle is the floral emblem of Scotland and Lorraine, as well as the emblem of the Encyclopædia Britannica.
Taxonomy
Genera in the Asteraceae with the word thistle often used in their common names include:
Carduus – musk thistle and others
Carduinae – burdock root
Carlina – carline thistle
Carthamus – distaff thistle
Centaurea – star thistle
Cicerbita – sow thistle
Cirsium – common thistle, field thistle and others
Cnicus – blessed thistle
Cynara – artichoke, cardoon
Echinops – globe thistle
Notobasis – Syrian thistle
Onopordum – cotton thistle, also known as Scots or Scotch thistle
Scolymus – golden thistle or oyster thistle
Silybum – milk thistle
Sonchus – sow thistle
Plants in families other than Astera |
https://en.wikipedia.org/wiki/EtherChannel | EtherChannel is a port link aggregation technology or port-channel architecture used primarily on Cisco switches. It allows grouping of several physical Ethernet links to create one logical Ethernet link for the purpose of providing fault-tolerance and high-speed links between switches, routers and servers. An EtherChannel can be created from between two and eight active Fast, Gigabit or 10-Gigabit Ethernet ports, with an additional one to eight inactive (failover) ports which become active as the other active ports fail. EtherChannel is primarily used in the backbone network, but can also be used to connect end user machines.
EtherChannel technology was invented by Kalpana in the early 1990s. Kalpana was acquired by Cisco Systems in 1994. In 2000, the IEEE passed 802.3ad, which is an open standard version of EtherChannel.
Benefits
Using an EtherChannel has numerous advantages, and probably the most desirable aspect is the bandwidth. Using the maximum of 8 active ports a total bandwidth of 800 Mbit/s, 8 Gbit/s or 80 Gbit/s is possible depending on port speed. This assumes there is a traffic mixture, as those speeds do not apply to a single application only. It can be used with Ethernet running on twisted pair wiring, single-mode and multimode fiber.
Because EtherChannel takes advantage of existing wiring it makes it very scalable. It can be used at all levels of the network to create higher bandwidth links as the traffic needs of the network increase. All Cisco switches have the ability to support EtherChannel.
When an EtherChannel is configured all adapters that are part of the channel share the same Layer 2 (MAC) address. This makes the EtherChannel transparent to network applications and users because they only see the one logical connection; they have no knowledge of the individual links.
EtherChannel aggregates the traffic across all the available active ports in the channel. The port is selected using a Cisco-proprietary hash algorithm, based on source o |
https://en.wikipedia.org/wiki/Decomposition%20%28computer%20science%29 | Decomposition in computer science, also known as factoring, is breaking a complex problem or system into parts that are easier to conceive, understand, program, and maintain.
Overview
There are different types of decomposition defined in computer sciences:
In structured programming, algorithmic decomposition breaks a process down into well-defined steps.
Structured analysis breaks down a software system from the system context level to system functions and data entities as described by Tom DeMarco.<ref>Tom DeMarco (1978). Structured Analysis and System Specification. New York, NY: Yourdon, 1978. , .</ref>
Object-oriented decomposition, on the other hand, breaks a large system down into progressively smaller classes or objects that are responsible for some part of the problem domain.
According to Booch, algorithmic decomposition is a necessary part of object-oriented analysis and design, but object-oriented systems start with and emphasize decomposition into objects.
More generally, functional decomposition in computer science is a technique for mastering the complexity of the function of a model. A functional model of a system is thereby replaced by a series of functional models of subsystems.
Decomposition topics
Decomposition paradigm
A decomposition paradigm in computer programming is a strategy for organizing a program as a number of parts, and it usually implies a specific way to organize a program text. Usually the aim of using a decomposition paradigm is to optimize some metric related to program complexity, for example the modularity of the program or its maintainability.
Most decomposition paradigms suggest breaking down a program into parts so as to minimize the static dependencies among those parts, and to maximize the cohesiveness of each part. Some popular decomposition paradigms are the procedural, modules, abstract data type and object oriented ones.
The concept of decomposition paradigm is entirely independent and different from that |
https://en.wikipedia.org/wiki/Obturator%20internus%20muscle | The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.
It exits the pelvic cavity through the lesser sciatic foramen.
The internal obturator is situated partly within the lesser pelvis, and partly at the back of the hip-joint.
It functions to help laterally rotate femur with hip extension and abduct femur with hip flexion, as well as to steady the femoral head in the acetabulum.
Structure
Origin
The internal obturator muscle arises from the inner surface of the antero-lateral wall of the pelvis. It surrounds the obturator foramen. It is attached to the inferior pubic ramus and ischium, and at the side to the inner surface of the hip bone below and behind the pelvic brim. It reaches from the upper part of the greater sciatic foramen above and behind to the obturator foramen below and in front.
It also arises from the pelvic surface of the obturator membrane. This is except in the posterior part, from the tendinous arch which completes the canal for the passage of the obturator vessels and nerve, and to a slight extent from the obturator fascia, which covers the muscle.
Passage
The fibers converge through the lesser sciatic foramen. These end in four or five tendinous bands, which are found on the deep surface of the muscle. These bands are reflected at a right angle over the grooved surface of the ischium between its spine and tuberosity.
The obturator nerve passes on the superficial surface of the internal obturator muscle. The pudendal nerve passes on the lateral surface of the internal obturator muscle and the coccygeus muscle. The sciatic nerve passes superficial to the internal obturator muscle on the posterior surface.
Insertion
The tendon inserts on the greater trochanter of the proximal femur.
Nerve supply
The internal obturator muscle is supplied by the obturator internus nerve (L5, S1, and S2).
Bursa/bands
This bony surface |
https://en.wikipedia.org/wiki/Cisco%20Inter-Switch%20Link | Cisco Inter-Switch Link (ISL) is a Cisco Systems proprietary protocol that maintains VLAN information in Ethernet frames as traffic flows between switches and routers, or switches and switches. ISL is Cisco's VLAN encapsulation protocol and is supported only on some Cisco equipment over the Fast and Gigabit Ethernet links. It is offered as an alternative to the IEEE 802.1Q standard, a widely used VLAN tagging protocol, although the use of ISL for new sites is deprecated by Cisco.
With ISL, an Ethernet frame is encapsulated with a header that transports VLAN IDs between switches and routers. With IEEE 802.1Q the tag is internal. This is a key advantage for IEEE 802.1Q as it means tagged frames can be sent over standard Ethernet links.
ISL does add overhead to the frame as a 26-byte header containing a 10-bit VLAN ID. In addition, a 4-byte CRC is appended to the end of each frame. This CRC is in addition to any frame checking that the Ethernet frame requires. The fields in an ISL header identify the frame as belonging to a particular VLAN.
A VLAN ID is added only if the frame is forwarded out a port configured as a trunk link. If the frame is to be forwarded out a port configured as an access link, the ISL encapsulation is removed.
The size of an Ethernet encapsulated ISL frame can be expected to start from 94 bytes and increase up to 1548 bytes because of the overhead (additional fields) the protocol creates via encapsulation. ISL adds a 26-byte header (containing a 15-bit VLAN identifier) and a 4-byte CRC trailer to the frame. ISL functions at the data-link layer of the OSI model.
Another related Cisco protocol, Dynamic Inter-Switch Link Protocol (DISL), simplifies the creation of an ISL trunk from two interconnected Fast Ethernet devices. Fast EtherChannel technology enables aggregation of two full-duplex Fast Ethernet links for high-capacity backbone connections. DISL minimizes VLAN trunk configuration procedures because only one end of a link needs to be |
https://en.wikipedia.org/wiki/Medial%20pterygoid%20muscle | The medial pterygoid muscle (or internal pterygoid muscle), is a thick, quadrilateral muscle of the face. It is supplied by the mandibular branch of the trigeminal nerve (V). It is important in mastication (chewing).
Structure
The medial pterygoid muscle consists of two heads. The bulk of the muscle arises as a deep head from just above the medial surface of the lateral pterygoid plate. The smaller, superficial head originates from the maxillary tuberosity and the pyramidal process of the palatine bone.
Its fibers pass downward, lateral, and posterior, and are inserted, by a strong tendinous lamina, into the lower and back part of the medial surface of the ramus and angle of the mandible, as high as the mandibular foramen. The insertion joins the masseter muscle to form a common tendinous sling which allows the medial pterygoid and masseter to be powerful elevators of the jaw.
Nerve supply
The medial pterygoid muscle is supplied by the medial pterygoid nerve, a branch of the mandibular nerve, itself a branch of the trigeminal nerve (V). This also supplies the tensor tympani muscle and the tensor veli palatini muscle. The medial pterygoid nerve is a main trunk from the mandibular nerve, before the division of the trigeminal nerve - this is unlike the lateral pterygoid muscle, and all other muscles of mastication which are supplied by the anterior division of the mandibular nerve.
Function
The medial pterygoid muscle has functions including elevating the mandible (closing the mouth), protruding the mandible, mastication (especially for when the maxillary teeth and the mandibular teeth are close together), and excursing the mandible (contralateral excursion occurs with unilateral contraction).
Additional images |
https://en.wikipedia.org/wiki/Actor%20model%20theory | In theoretical computer science, Actor model theory concerns theoretical issues for the Actor model.
Actors are the primitives that form the basis of the Actor model of concurrent digital computation. In response to a message that it receives, an Actor can make local decisions, create more Actors, send more messages, and designate how to respond to the next message received. Actor model theory incorporates theories of the events and structures of Actor computations, their proof theory, and denotational models.
Events and their orderings
From the definition of an Actor, it can be seen that numerous events take place: local decisions, creating Actors, sending messages, receiving messages, and designating how to respond to the next message received.
However, this article focuses on just those events that are the arrival of a message sent to an Actor.
This article reports on the results published in Hewitt [2006].
Law of Countability: There are at most countably many events.
Activation ordering
The activation ordering (-≈→) is a fundamental ordering that models one event activating another (there must be energy flow in the message passing from an event to an event which it activates).
Because of the transmission of energy, the activation ordering is relativistically invariant; that is, for all events e1.e2, if e1 -≈→ e2, then the time of e1 precedes the time of e2 in the relativistic frames of reference of all observers.
Law of Strict Causality for the Activation Ordering: For no event does e -≈→ e.
Law of Finite Predecession in the Activation Ordering: For all events e1 the set {e|e -≈→ e1} is finite.
Arrival orderings
The arrival ordering of an Actor x ( -x→ ) models the (total) ordering of events in which a message arrives at x. Arrival ordering is determined by arbitration in processing messages (often making use of a digital circuit called an arbiter). The arrival events of an Actor are on its world line. The arrival ordering means that the Actor mo |
https://en.wikipedia.org/wiki/Falling%20on%20a%20grenade | Falling on a grenade is the deliberate act of using one's body to cover a live time-fused hand grenade, absorbing the explosion and fragmentation in an effort to save the lives of others nearby. Since this is almost universally fatal, it is considered an especially conspicuous and selfless act of individual sacrifice in wartime; in United States military history, more citations for the Medal of Honor, the country's highest military decoration, have been awarded for falling on grenades to save comrades than any other single act.
Such an act can be survivable: in World War II, U.S. Marine Jack Lucas, in the Battle of Iwo Jima, put his steel M1 helmet over two grenades and laid on top of it before the grenades exploded. Lucas lived, but spent the rest of his life with over 200 pieces of shrapnel in his body. In 2008 near Sangin in Afghanistan, British Royal Marine Matthew Croucher used his rucksack to pin a tripwire grenade to the floor; his body armor absorbed the majority of the blast. On November 21, 2010, in Marjah, Helmand Province, Afghanistan in support of Operation Enduring Freedom, U.S. Marine Lance Corporal Kyle Carpenter threw himself upon a grenade, thrown onto a rooftop, to save a fellow Marine, sustaining injuries to his face and right arm and losing his right eye; he survived these wounds. Despite these rare instances, however, the odds of survival are extremely slim. With modern medicine, however, odds are greatly increased when compared to falling on a grenade in the 20th century.
In World War I British soldier John Carmichael was awarded the Victoria Cross for saving his men by putting his steel helmet over a grenade and then standing on the helmet to reduce the blast damage. Carmichael survived although it was several years before he recovered sufficiently to be discharged from hospital.
See also
Altruistic suicide
Human shield
William McFadzean
John Robert Osborn
Roi Klein
Nathan Elbaz
Matan Abargil
Netta Epstein |
https://en.wikipedia.org/wiki/Vernon%20Coleman | Vernon Edward Coleman (born 1946) is an English conspiracy theorist, writer, novelist, anti-vivisectionist, anti-vaccination activist and AIDS denialist who writes on topics related to human health, politics and animal welfare. He was formerly a general practitioner (GP) and newspaper columnist.
Coleman's medical claims have been widely discredited and described as pseudoscientific conspiracy theories.
Early life
Coleman was born in 1946, the only child of an electrical engineer. He was raised in Walsall, Staffordshire, in the West Midlands of England, where he attended Queen Mary's Grammar School and a medical school in Birmingham.
Career
Coleman qualified as a physician in 1970 and worked as a GP. In 1981, the Department of Health and Social Security (DHSS) fined him for refusing to write the diagnoses on sick notes, which he considered a breach of patient confidentiality.
After publishing his first book, The Medicine Men, in 1976, which accused the National Health Service of being controlled by pharmaceutical companies, Coleman left the NHS.
Coleman has since written under multiple pen names; in the late 1970s, he published three novels about life as a GP under the name Edward Vernon.
In 1987 Coleman appeared on the Central Weekend Programme as a sceptic against jogging for fitness.
An anti-vivisectionist, Coleman provided a supplementary memorandum for the House of Lords on the topic of vivisection in 1993.
In 1994 Coleman was ordered to pay damages for threatening scientist Colin Blakemore, who had been targeted by anti-vivisection activists after a letter bomb sent by animal rights group calling itself 'The Justice Department' was sent to Blakemore's home, with another exploding and injuring three people. Blakemore was later granted a temporary injunction by a High Court judge after Coleman had said he would publish a pamphlet with Blakemore's home address and telephone number to encourage the public to 'get in touch with you to discuss your work'. C |
https://en.wikipedia.org/wiki/4-Aminopyridine | 4-Aminopyridine (4-AP, fampridine, dalfampridine) is an organic compound with the chemical formula C5H4N–NH2. The molecule is one of the three isomeric amines of pyridine. It is used as a research tool in characterizing subtypes of the potassium channel. It has also been used as a drug, to manage some of the symptoms of multiple sclerosis, and is indicated for symptomatic improvement of walking in adults with several variations of the disease. It was undergoing Phase III clinical trials , and the U.S. Food and Drug Administration (FDA) approved the compound on January 22, 2010. Fampridine is also marketed as Ampyra (pronounced "am-PEER-ah," according to the maker's website) in the United States by Acorda Therapeutics and as Fampyra in the European Union, Canada, and Australia. In Canada, the medication has been approved for use by Health Canada since February 10, 2012.
Applications
In the laboratory, 4-AP is a useful pharmacological tool in studying various potassium conductances in physiology and biophysics. It is a relatively selective blocker of members of Kv1 (Shaker, KCNA) family of voltage-activated K+ channels. However, 4-AP has been shown to potentiate voltage-gated Ca2+ channel currents independent of effects on voltage-activated K+ channels.
Convulsant activity
4-Aminopyridine is a potent convulsant and is used to generate seizures in animal models for the evaluation of antiseizure agents.
Vertebrate pesticide
4-Aminopyridine is also used under the trade name Avitrol as 0.5% or 1% in bird control bait. It causes convulsions and, infrequently, death, depending on dosage. The manufacturer says the proper dose should cause epileptic-like convulsions which cause the poisoned birds to emit distress calls resulting in the flock leaving the site; if the dose was sub-lethal, the birds will recover after 4 or more hours without long-term ill effect. The amount of bait should be limited so that relatively few birds are poisoned, causing the remainder of the fl |
https://en.wikipedia.org/wiki/Resultant | In mathematics, the resultant of two polynomials is a polynomial expression of their coefficients that is equal to zero if and only if the polynomials have a common root (possibly in a field extension), or, equivalently, a common factor (over their field of coefficients). In some older texts, the resultant is also called the eliminant.
The resultant is widely used in number theory, either directly or through the discriminant, which is essentially the resultant of a polynomial and its derivative. The resultant of two polynomials with rational or polynomial coefficients may be computed efficiently on a computer. It is a basic tool of computer algebra, and is a built-in function of most computer algebra systems. It is used, among others, for cylindrical algebraic decomposition, integration of rational functions and drawing of curves defined by a bivariate polynomial equation.
The resultant of n homogeneous polynomials in n variables (also called multivariate resultant, or Macaulay's resultant for distinguishing it from the usual resultant) is a generalization, introduced by Macaulay, of the usual resultant. It is, with Gröbner bases, one of the main tools of elimination theory.
Notation
The resultant of two univariate polynomials and is commonly denoted or
In many applications of the resultant, the polynomials depend on several indeterminates and may be considered as univariate polynomials in one of their indeterminates, with polynomials in the other indeterminates as coefficients. In this case, the indeterminate that is selected for defining and computing the resultant is indicated as a subscript: or
The degrees of the polynomials are used in the definition of the resultant. However, a polynomial of degree may also be considered as a polynomial of higher degree where the leading coefficients are zero. If such a higher degree is used for the resultant, it is usually indicated as a subscript or a superscript, such as or
Definition
The resultant of two u |
https://en.wikipedia.org/wiki/Rational%20zeta%20series | In mathematics, a rational zeta series is the representation of an arbitrary real number in terms of a series consisting of rational numbers and the Riemann zeta function or the Hurwitz zeta function. Specifically, given a real number x, the rational zeta series for x is given by
where qn is a rational number, the value m is held fixed, and ζ(s, m) is the Hurwitz zeta function. It is not hard to show that any real number x can be expanded in this way.
Elementary series
For integer m>1, one has
For m=2, a number of interesting numbers have a simple expression as rational zeta series:
and
where γ is the Euler–Mascheroni constant. The series
follows by summing the Gauss–Kuzmin distribution. There are also series for π:
and
being notable because of its fast convergence. This last series follows from the general identity
which in turn follows from the generating function for the Bernoulli numbers
Adamchik and Srivastava give a similar series
Polygamma-related series
A number of additional relationships can be derived from the Taylor series for the polygamma function at z = 1, which is
.
The above converges for |z| < 1. A special case is
which holds for |t| < 2. Here, ψ is the digamma function and ψ(m) is the polygamma function. Many series involving the binomial coefficient may be derived:
where ν is a complex number. The above follows from the series expansion for the Hurwitz zeta
taken at y = −1. Similar series may be obtained by simple algebra:
and
and
and
For integer n ≥ 0, the series
can be written as the finite sum
The above follows from the simple recursion relation Sn + Sn + 1 = ζ(n + 2). Next, the series
may be written as
for integer n ≥ 1. The above follows from the identity Tn + Tn + 1 = Sn. This process may be applied recursively to obtain finite series for general expressions of the form
for positive integers m.
Half-integer power series
Similar series may be obtained by exploring the Hurwitz zeta function at half-integer va |
https://en.wikipedia.org/wiki/ATM%20serine/threonine%20kinase | ATM serine/threonine kinase or Ataxia-telangiectasia mutated, symbol ATM, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks (canonical pathway), oxidative stress, topoisomerase cleavage complexes, splicing intermediates, R-loops and in some cases by single-strand DNA breaks. It phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Several of these targets, including p53, CHK2, BRCA1, NBS1 and H2AX are tumor suppressors.
In 1995, the gene was discovered by Yosef Shiloh who named its product ATM since he found that its mutations are responsible for the disorder ataxia–telangiectasia. In 1998, the Shiloh and Kastan laboratories independently showed that ATM is a protein kinase whose activity is enhanced by DNA damage.
Introduction
Throughout the cell cycle DNA is monitored for damage. Damages result from errors during replication, by-products of metabolism, general toxic drugs or ionizing radiation. The cell cycle has different DNA damage checkpoints, which inhibit the next or maintain the current cell cycle step. There are two main checkpoints, the G1/S and the G2/M, during the cell cycle, which preserve correct progression. ATM plays a role in cell cycle delay after DNA damage, especially after double-strand breaks (DSBs). ATM is recruited to sites of double strand breaks by DSB sensor proteins, such as the MRN complex. After being recruited, it phosphorylates NBS1, along other DSB repair proteins. These modified mediator proteins then amplify the DNA damage signal, and transduce the signals to downstream effectors such as CHK2 and p53.
Structure
The ATM gene codes for a 350 kDa protein consisting of 3056 amino acids. ATM belongs to the superfamily of phosphatidylinositol 3-kinase-related kinases (PIKKs). The PIKK superfamily comprises six Ser/Thr-protein kinases that show a sequence similarity to phosphatidylinositol 3-kinas |
https://en.wikipedia.org/wiki/Gopher | Pocket gophers, commonly referred to simply as gophers, are burrowing rodents of the family Geomyidae. The roughly 41 species are all endemic to North and Central America. They are commonly known for their extensive tunneling activities and their ability to destroy farms and gardens.
The name "pocket gopher" on its own may refer to any of a number of genera within the family Geomyidae. These are the "true" gophers, but several ground squirrels in the distantly related family Sciuridae are often called "gophers", as well. The origin of the word "gopher" is uncertain; the French gaufre, meaning waffle, has been suggested, on account of the gopher tunnels resembling the honeycomb-like pattern of holes in a waffle; another suggestion is that the word is of Muskogean origin.
Description
Pocket gophers weigh around , and are about in body length, with a tail long. A few species reach weights approaching . Within any species, the males are larger than the females, and can be nearly double their weight.
Average lifespans are one to three years. The maximum lifespan for the pocket gopher is about five years. Some gophers, such as those in the genus Geomys, have lifespans that have been documented as up to seven years in the wild.
Most gophers have brown fur that often closely matches the color of the soil in which they live. Their most characteristic features are their large cheek pouches, from which the word "pocket" in their name derives. These pouches are fur-lined, can be turned inside out, and extend from the side of the mouth well back onto the shoulders. Gophers have small eyes and a short, hairy tail, which they use to feel around tunnels when they walk backwards.
Pocket gophers have often been found to carry external parasites including, most commonly, lice, but also ticks, fleas, and mites. Common predators of the gopher include weasels, snakes, and hawks.
Behavior
All pocket gophers create a network of tunnel systems that provide protection and a mea |
https://en.wikipedia.org/wiki/Actor%20model%20and%20process%20calculi | In computer science, the Actor model and process calculi are two closely related approaches to the modelling of concurrent digital computation. See Actor model and process calculi history.
There are many similarities between the two approaches, but also several differences (some philosophical, some technical):
There is only one Actor model (although it has numerous formal systems for design, analysis, verification, modeling, etc.); there are numerous process calculi, developed for reasoning about a variety of different kinds of concurrent systems at various levels of detail (including calculi that incorporate time, stochastic transitions, or constructs specific to application areas such as security analysis).
The Actor model was inspired by the laws of physics and depends on them for its fundamental axioms, i.e. physical laws (see Actor model theory); the process calculi were originally inspired by algebra .
Processes in the process calculi are anonymous, and communicate by sending messages either through named channels (synchronous or asynchronous), or via ambients (which can also be used to model channel-like communications ). In contrast, actors in the Actor model possess an identity, and communicate by sending messages to the mailing addresses of other actors (this style of communication can also be used to model channel-like communications—see below).
The publications on the Actor model and on process calculi have a fair number of cross-references, acknowledgments, and reciprocal citations (see Actor model and process calculi history).
How channels work
Indirect communication using channels (e.g. Gilles Kahn and David MacQueen [1977]) has been an important issue for communication in parallel and concurrent computation affecting both semantics and performance. Some process calculi differ from the Actor model in their use of channels as opposed to direct communication.
Synchronous channels
Synchronous channels have the property that a sender putting a mess |
https://en.wikipedia.org/wiki/California%20Senate%20Bill%201386%20%282002%29 | California S.B. 1386 was a bill passed by the California legislature that amended the California law regulating the privacy of personal information: civil codes 1798.29, 1798.82 and 1798.84. This was an early example of many future U.S. and international security breach notification laws, it was introduced by California State Senator Steve Peace on February 12, 2002, and became operative July 1, 2003.
Sections
Enactment of a requirement for notification to any resident of California whose unencrypted personal information was, or is reasonably believed to have been, acquired by an unauthorized person. This requires an agency, person or business that conducts business in California and owns or licenses to computerized 'personal information,' to disclose any breach of security (to any resident whose unencrypted data is believed to have been disclosed).
The bill mandates various mechanisms and procedures with respect to many aspects of this scenario, subject also to other defined provisions.
Any agency that owns or licenses computerized data that includes personal information shall disclose any breach of the security of the system following discovery or notification of the breach in the security of the data to any resident of California whose unencrypted personal information was, or is reasonably believed to have been, acquired by an unauthorized person. An out-of-state corporation that has personal information relating to a California resident would fall under this statute. A question on minimum contacts would then ensue as to whether an action may be brought in California to enforce the California resident's rights under the statute.
Corporations with no physical locations in California are not subject to California law. SB 1386 no more impacts a Delaware corporation with no presence in California than do California laws regarding vehicle emissions. That SB 1386 would affect an out-of-state corporation is based on the notion of 'quasi in rem' jurisdiction, a no |
https://en.wikipedia.org/wiki/Swimmer%27s%20itch | Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the skin of humans that have been infected by water-borne schistosomes, a type of flatworm. It is common in freshwater, brackish and marine habitats worldwide. The incidence of this condition may be increasing, although this may be attributed to better monitoring and reporting. Nevertheless, the condition is considered to be an emerging infectious disease.
The main symptom is itchy papules (raised skin) that commonly occur within 2 days of infection. Initially, wheals develop quickly, then turn into maculae in about half an hour. Within 10–12 hours these turn into very itchy papules that reach their worst by the second or third day. The papules disappear in 1–2 weeks but secondary effects from scratching can continue longer. The intense itching, which peaks after 48–72 hours, is associated with pain and swelling of the affected areas. People repeatedly exposed to cercariae develop heavier symptoms with faster onset.
There are no permanent effects to people from this condition. Orally administered hydroxyzine, an antihistamine, is sometimes prescribed to treat swimmer's itch and similar dermal allergic reactions. In addition, bathing in oatmeal, baking soda, or Epsom salts can also provide relief of symptoms.
Cause
Swimmer's itch was known to exist as early as the 19th century, but it was not until 1928 that a biologist found that the dermatitis was caused by the larval stage of a group of flatworm parasites in the family Schistosomatidae. The genera most commonly associated with swimmer's itch in humans are Trichobilharzia and Gigantobilharzia. It can also be caused by schistosome parasites of non-avian vertebrates, such as Schistosomatium douthitti, which infects snails and rodents. Other taxa reported to cause the reaction include Bilharziella polonica and Schistosoma bovis. In marine environments, especially along the coasts, swimmer's itch c |
https://en.wikipedia.org/wiki/Apparent%20death | Apparent death is a behavior in which animals take on the appearance of being dead. It is an immobile state most often triggered by a predatory attack and can be found in a wide range of animals from insects and crustaceans to mammals, birds, reptiles, amphibians, and fish. Apparent death is separate from the freezing behavior seen in some animals.
Apparent death is a form of animal deception considered to be an anti-predator strategy, but it can also be used as a form of aggressive mimicry. When induced by humans, the state is sometimes colloquially known as animal hypnosis. The earliest written record of "animal hypnosis" dates back to the year 1646 in a report by Athanasius Kircher, in which he subdued chickens.
Description
Tonic immobility (also known as the act of feigning death, or exhibiting thanatosis) is a behaviour in which some animals become apparently temporarily paralysed and unresponsive to external stimuli. Tonic immobility is most generally considered to be an anti-predator behavior because it occurs most often in response to an extreme threat such as being captured by a (perceived) predator. Some animals use it to attract prey or facilitate reproduction. For example, in sharks exhibiting the behaviour, some scientists relate it to mating, arguing that biting by the male immobilizes the female and thus facilitates mating.
Despite appearances, some animals remain conscious throughout tonic immobility. Evidence for this includes the occasional responsive movement, scanning of the environment and animals in tonic immobility often taking advantage of escape opportunities. Tonic immobility is preferred in the literature because it has neutral connotations compared to 'thanatosis' which has a strong association with death.
Difference from freezing
Tonic immobility is different from freezing behavior in animals. A deer in headlights and an opossum "playing dead" are common examples of an animal freezing and playing dead, respectively. Freezing occur |
https://en.wikipedia.org/wiki/Gauss%E2%80%93Kuzmin%20distribution | In mathematics, the Gauss–Kuzmin distribution is a discrete probability distribution that arises as the limit probability distribution of the coefficients in the continued fraction expansion of a random variable uniformly distributed in (0, 1). The distribution is named after Carl Friedrich Gauss, who derived it around 1800, and Rodion Kuzmin, who gave a bound on the rate of convergence in 1929. It is given by the probability mass function
Gauss–Kuzmin theorem
Let
be the continued fraction expansion of a random number x uniformly distributed in (0, 1). Then
Equivalently, let
then
tends to zero as n tends to infinity.
Rate of convergence
In 1928, Kuzmin gave the bound
In 1929, Paul Lévy improved it to
Later, Eduard Wirsing showed that, for λ = 0.30366... (the Gauss–Kuzmin–Wirsing constant), the limit
exists for every s in [0, 1], and the function Ψ(s) is analytic and satisfies Ψ(0) = Ψ(1) = 0. Further bounds were proved by K. I. Babenko.
See also
Khinchin's constant
Lévy's constant |
https://en.wikipedia.org/wiki/Tiabendazole | Tiabendazole (INN, BAN), also known as thiabendazole (AAN, USAN) or TBZ and the trade names Mintezol, Tresaderm, and Arbotect, is a preservative, an antifungal agent, and an antiparasitic agent.
Uses
Preservative
Tiabendazole is used primarily to control mold, blight, and other fungal diseases in fruits (e.g. oranges) and vegetables; it is also used as a prophylactic treatment for Dutch elm disease.
Tiabendazole is also used as a food additive, a preservative with E number E233 (INS number 233). For example, it is applied to bananas to ensure freshness, and is a common ingredient in the waxes applied to the skins of citrus fruits. It is not approved as a food additive in the EU, Australia and New Zealand.
Use in treatment of aspergillosis has been reported.
It is also used in anti-fungal wallboards as a mixture with azoxystrobin.
Parasiticide
As an antiparasitic, tiabendazole is able to control roundworms (such as those causing strongyloidiasis), hookworms, and other helminth species which infect wild animals, livestock, and humans.
Other
In dogs and cats, tiabendazole is used to treat ear infections.
Tiabendazole is also a chelating agent, which means it is used medicinally to bind metals in cases of metal poisoning, such as lead, mercury, or antimony poisoning.
Research
Genes responsible for the maintenance of cell walls in yeast have been shown to be responsible for angiogenesis in vertebrates. Tiabendazole serves to block angiogenesis in both frog embryos and human cells. It has also been shown to serve as a vascular disrupting agent to reduce newly established blood vessels. Tiabendazole has been shown to effectively do this in certain cancer cells.
Pharmacodynamics
Tiabendazole works by inhibition of the mitochondrial, helminth-specific enzyme, fumarate reductase, with possible interaction with endogenous quinone.
Safety
The substance appears to have a slight toxicity in higher doses, with effects such as liver and intestinal disorders at h |
https://en.wikipedia.org/wiki/IP%20%28complexity%29 | In computational complexity theory, the class IP (interactive proof) is the class of problems solvable by an interactive proof system. It is equal to the class PSPACE. The result was established in a series of papers: the first by Lund, Karloff, Fortnow, and Nisan showed that co-NP had multiple prover interactive proofs; and the second, by Shamir, employed their technique to establish that IP=PSPACE. The result is a famous example where the proof does not relativize.
The concept of an interactive proof system was first introduced by Shafi Goldwasser, Silvio Micali, and Charles Rackoff in 1985. An interactive proof system consists of two machines, a prover, P, which presents a proof that a given string n is a member of some language, and a verifier, V, that checks that the presented proof is correct. The prover is assumed to be infinite in computation and storage, while the verifier is a probabilistic polynomial-time machine with access to a random bit string whose length is polynomial on the size of n. These two machines exchange a polynomial number, p(n), of messages and once the interaction is completed, the verifier must decide whether or not n is in the language, with only a 1/3 chance of error. (So any language in BPP is in IP, since then the verifier could simply ignore the prover and make the decision on its own.)
Definition
A language L belongs to IP if there exist V, P such that for all Q, w:
The Arthur–Merlin protocol, introduced by László Babai, is similar in nature, except that the number of rounds of interaction is bounded by a constant rather than a polynomial.
Goldwasser et al. have shown that public-coin protocols, where the random numbers used by the verifier are provided to the prover along with the challenges, are no less powerful than private-coin protocols. At most two additional rounds of interaction are required to replicate the effect of a private-coin protocol. The opposite inclusion is straightforward, because the verifier can always s |
https://en.wikipedia.org/wiki/Harvard%20Mark%20III | The Harvard Mark III, also known as ADEC (for Aiken Dahlgren Electronic Calculator) was an early computer that was partially electronic and partially electromechanical. It was built at Harvard University under the supervision of Howard Aiken for use at Naval Surface Warfare Center Dahlgren Division.
Technical overview
The Mark III processed numbers of 16 decimal digits (plus sign), each digit encoded with four bits, though using a form of encoding that is different to conventional binary-coded decimal today. Numbers were read and processed serially, meaning one decimal digit at a time, but the four bits for the digit were read in parallel. The instruction length, however, was 38 bits, read in parallel.
It used 5,000 vacuum tubes and 1,500 crystal diodes. It weighed . It used magnetic drum memory of 4,350 words. Its addition time was 4,400 microseconds and the multiplication time was 13,200 microseconds (times include memory access time). Aiken boasted that the Mark III was the fastest electronic computer in the world.
The Mark III used nine magnetic drums (one of the first computers to do so). One drum could contain 4,000 instructions and has an access time of 4,400 microseconds; thus it was a stored-program computer. The arithmetic unit could access two other drums – one contained 150 words of constants and the other contained 200 words of variables. Both of these drums also had an access time of 4,400 microseconds. This separation of data and instructions is now sometimes referred to as the Harvard architecture although that term was not coined until the 1970s (in the context of microcontrollers). There were six other drums that held a total of 4,000 words of data, but the arithmetic unit couldn't access these drums directly. Data had to be transferred between these drums and the drum the arithmetic unit could access via registers implemented by electromechanical relays. This was a bottleneck in the computer and made the access time to data on these drums long |
https://en.wikipedia.org/wiki/Dentinogenesis | Dentinogenesis is the formation of dentin, a substance that forms the majority of teeth. Dentinogenesis is performed by odontoblasts, which are a special type of biological cell on the outer wall of dental pulps, and it begins at the late bell stage of a tooth development. The different stages of dentin formation after differentiation of the cell result in different types of dentin: mantle dentin, primary dentin, secondary dentin, and tertiary dentin.
Odontoblast differentiation
Odontoblasts differentiate from cells of the dental papilla. This is an expression of signaling molecules and growth factors of the inner enamel epithelium (IEE).
Formation of mantle dentin
They begin secreting an organic matrix around the area directly adjacent to the IEE, closest to the area of the future cusp of a tooth. The organic matrix contains collagen fibers with large diameters (0.1-0.2 μm in diameter). The odontoblasts begin to move toward the center of the tooth, forming an extension called the odontoblast process. Thus, dentin formation proceeds toward the inside of the tooth. The odontoblast process causes the secretion of hydroxyapatite crystals and mineralization of the matrix (mineralisation occurs due to matrix vesicles). This area of mineralization is known as mantle dentin and is a layer usually about 20-150 μm thick.
Formation of primary dentin
Whereas mantle dentin forms from the preexisting ground substance of the dental papilla, primary dentin forms through a different process. Odontoblasts increase in size, eliminating the availability of any extracellular resources to contribute to an organic matrix for mineralization. Additionally, the larger odontoblasts cause collagen to be secreted in smaller amounts, which results in more tightly arranged, heterogeneous nucleation that is used for mineralization. Other materials (such as lipids, phosphoproteins, and phospholipids) are also secreted. There is some dispute about the control of mineralization during de |
https://en.wikipedia.org/wiki/Zeta%20function%20universality | In mathematics, the universality of zeta functions is the remarkable ability of the Riemann zeta function and other similar functions (such as the Dirichlet L-functions) to approximate arbitrary non-vanishing holomorphic functions arbitrarily well.
The universality of the Riemann zeta function was first proven by in 1975 and is sometimes known as Voronin's universality theorem.
Formal statement
A mathematically precise statement of universality for the Riemann zeta function ζ(s) follows.
Let U be a compact subset of the strip
such that the complement of U is connected. Let be a continuous function on U which is holomorphic on the interior of U and does not have any zeros in U. Then for any there exists a such that
for all .
Even more: the lower density of the set of values t satisfying the above inequality is positive. Precisely
where denotes the Lebesgue measure on the real numbers and denotes the limit inferior.
Discussion
The condition that the complement of U be connected essentially means that U does not contain any holes.
The intuitive meaning of the first statement is as follows: it is possible to move U by some vertical displacement it so that the function f on U is approximated by the zeta function on the displaced copy of U, to an accuracy of ε.
The function f is not allowed to have any zeros on U. This is an important restriction; if we start with a holomorphic function with an isolated zero, then any "nearby" holomorphic function will also have a zero. According to the Riemann hypothesis, the Riemann zeta function does not have any zeros in the considered strip, and so it couldn't possibly approximate such a function. The function which is identically zero on U can be approximated by ζ: we can first pick the "nearby" function (which is holomorphic and does not have zeros) and find a vertical displacement such that ζ approximates g to accuracy ε/2, and therefore f to accuracy ε.
The accompanying figure shows the zeta function on a repre |
https://en.wikipedia.org/wiki/Trypanosoma%20brucei | Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids. It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or nagana in cattle and horses. It is a species complex grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human mammals and causes nagana, while the latter two are zoonotic infecting both humans and animals and cause African trypanosomiasis.
T. brucei is transmitted between mammal hosts by an insect vector belonging to different species of tsetse fly (Glossina). Transmission occurs by biting during the insect's blood meal. The parasites undergo complex morphological changes as they move between insect and mammal over the course of their life cycle. The mammalian bloodstream forms are notable for their cell surface proteins, variant surface glycoproteins, which undergo remarkable antigenic variation, enabling persistent evasion of host adaptive immunity leading to chronic infection. T. brucei is one of only a few pathogens known to cross the blood brain barrier. There is an urgent need for the development of new drug therapies, as current treatments can have severe side effects and can prove fatal to the patient.
Whilst not historically regarded as T. brucei subspecies due to their different means of transmission, clinical presentation, and loss of kinetoplast DNA, genetic analyses reveal that T. equiperdum and T. evansi are evolved from parasites very similar to T. b. brucei, and are thought to be members of the brucei clade.
The parasite was discovered in 1894 by Sir David Bruce, after whom the scientific name was given in 1899.
History and discovery
Early records
Sleeping sickness in anima |
https://en.wikipedia.org/wiki/Wet%20wipe | A wet wipe, also known as a wet towel, moist towelette, disposable wipe, disinfecting wipe, or a baby wipe (in specific circumstances) is a small to medium-sized moistened piece of plastic or cloth that either comes folded and individually wrapped for convenience or, in the case of dispensers, as a large roll with individual wipes that can be torn off. Wet wipes are used for cleaning purposes like personal hygiene and household cleaning; each is a separate product depending on the chemicals added and medical or office cleaning wipes are not intended for skin hygiene.
In 2013, owing to increasing sales of the product in affluent countries, Consumer Reports reported that efforts to make the wipes "flushable" down the toilet had not entirely succeeded, according to their test.
Invention
American Arthur Julius is seen as the inventor of wet wipes. Julius worked in the cosmetics industry and in 1957, adjusted a soap portioning machine, putting it in a loft in Manhattan. Julius trademarked the name Wet-Nap in 1958, a name for the product that is still being used. After fine tuning his new hand-cleaning aid together with a mechanic, he unveiled his invention at the 1960 National Restaurant Show in Chicago and in 1963 started selling Wet-Nap products to Colonel Harland Sanders to be distributed to customers of Kentucky Fried Chicken.
Production
Ninety percent of wet wipes on the market are produced from nonwoven fabrics made of polyester or polypropylene.
The material is moistened with water or other liquids (e.g., isopropyl alcohol) depending on the applications. The material may be treated with softeners, lotions, or perfume to adjust the tactile and olfactory properties. Preservatives such as methylisothiazolinone are used to prevent bacterial or fungal growth in the package. The finished wet wipes are folded and put in pocket size package or a box dispenser.
Uses
Wet wipes can serve a number of personal and household purposes. Although marketed primarily for wipi |
https://en.wikipedia.org/wiki/Unified%20Science | "Unified Science" can refer to any of three related strands in contemporary thought.
Belief in the unity of science was a central tenet of logical positivism. Different logical positivists construed this doctrine in several different ways, e.g. as a reductionist thesis, that the objects investigated by the special sciences reduce to the objects of a common, putatively more basic domain of science, usually thought to be physics; as the thesis that all of the theories and results of the various sciences can or ought to be expressed in a common language or "universal slang"; or as the thesis that all the special sciences share a common method.
The writings of Edward Haskell and a few associates, seeking to rework science into a single discipline employing a common artificial language. This work culminated in the 1972 publication of Full Circle: The Moral Force of Unified Science. The vast part of the work of Haskell and his contemporaries remains unpublished, however. Timothy Wilken and Anthony Judge have recently revived and extended the insights of Haskell and his coworkers.
Unified Science has been a consistent thread since the 1940s in Howard T. Odum's systems ecology and the associated Emergy Synthesis, modeling the "ecosystem": the geochemical, biochemical, and thermodynamic processes of the lithosphere and biosphere. Modeling such earthly processes in this manner requires a science uniting geology, physics, biology, and chemistry (H.T.Odum 1995). With this in mind, Odum developed a common language of science based on electronic schematics, with applications to ecology economic systems in mind (H.T.Odum 1994).
See also
Consilience — the unification of knowledge, e.g. science and the humanities
Tree of knowledge system |
https://en.wikipedia.org/wiki/Cross-covariance | In probability and statistics, given two stochastic processes and , the cross-covariance is a function that gives the covariance of one process with the other at pairs of time points. With the usual notation for the expectation operator, if the processes have the mean functions and , then the cross-covariance is given by
Cross-covariance is related to the more commonly used cross-correlation of the processes in question.
In the case of two random vectors and , the cross-covariance would be a matrix (often denoted ) with entries Thus the term cross-covariance is used in order to distinguish this concept from the covariance of a random vector , which is understood to be the matrix of covariances between the scalar components of itself.
In signal processing, the cross-covariance is often called cross-correlation and is a measure of similarity of two signals, commonly used to find features in an unknown signal by comparing it to a known one. It is a function of the relative time between the signals, is sometimes called the sliding dot product, and has applications in pattern recognition and cryptanalysis.
Cross-covariance of random vectors
Cross-covariance of stochastic processes
The definition of cross-covariance of random vectors may be generalized to stochastic processes as follows:
Definition
Let and denote stochastic processes. Then the cross-covariance function of the processes is defined by:
where and .
If the processes are complex-valued stochastic processes, the second factor needs to be complex conjugated:
Definition for jointly WSS processes
If and are a jointly wide-sense stationary, then the following are true:
for all ,
for all
and
for all
By setting (the time lag, or the amount of time by which the signal has been shifted), we may define
.
The cross-covariance function of two jointly WSS processes is therefore given by:
which is equivalent to
.
Uncorrelatedness
Two stochastic processes and are called uncorrelated i |
https://en.wikipedia.org/wiki/Saxifraga%20%C3%97%20urbium | Saxifraga × urbium, London pride, is an evergreen perennial garden flowering plant. Alternative names for it include St. Patrick's cabbage, whimsey, prattling Parnell, and look up and kiss me. Before 1700 the “London pride” appellation was given to the Sweet William (Dianthus barbatus).
In 1846, Theresa Cornwallis West made a journey to Ireland. Near Dunloe in County Kerry "heareabouts grew quantities of our London Pride, and upon my expressing a wish for some roots to carry home, Sullivan [the driver] sprang down and tore up a large tuft. 'Ah, then,' said [our guide Spillane], 'that's too much entirely; why wouldn't ye leave some for the next comer?'" (A Summer Visit to the West of Ireland in 1846, p. 99).
Taxonomy
The true London pride is a hybrid between Saxifraga umbrosa, native to the Spanish Pyrenees, and Saxifraga spathularis (the plant to which the name St Patrick's cabbage more correctly belongs, from western Ireland). The hybrid has been known at least since the 17th century.
The name is sometimes applied to any of several closely related plants of the saxifrage genus. The section Gymnopera is collectively referred to as "London Pride saxifrages", and others of them have "London pride" in their common names, for example the lesser London pride, S. cuneifolia, and the miniature London pride, S. umbrosa var. primuloides.
Description
London pride is tolerant of dry, shady conditions. It grows to a height of and provides rapid ground cover without being aggressively invasive, and in late spring produces a mass of small pale pink rosette flowers growing from succulent stems. It will grow well in neglected or unfavourable urban spaces where few other flowers flourish, and is a common garden escapee.
This plant has gained the Royal Horticultural Society's Award of Garden Merit.
Symbolism
Bishop Walsham How (1823–1897) wrote a poem to the flower rebuking it for having the sin of pride. When told the flower had the name because Londoners were proud of it he |
https://en.wikipedia.org/wiki/Gravity%20train | A gravity train is a theoretical means of transportation for purposes of commuting between two points on the surface of a sphere, by following a straight tunnel connecting the two points through the interior of the sphere.
In a large body such as a planet, this train could be left to accelerate using just the force of gravity, since during the first half of the trip (from the point of departure until the middle), the downward pull towards the center of gravity would pull it towards the destination. During the second half of the trip, the acceleration would be in the opposite direction relative to the trajectory, but, ignoring the effects of friction, the speed acquired before would be overcome this deceleration, and as a result, the train's speed would reach zero at approximately the moment the train reached its destination.
Origin of the concept
In the 17th century, British scientist Robert Hooke presented the idea of an object accelerating inside a planet in a letter to Isaac Newton. A gravity train project was seriously presented to the French Academy of Sciences in the 19th century. The same idea was proposed, without calculation, by Lewis Carroll in 1893 in Sylvie and Bruno Concluded. The idea was rediscovered in the 1960s when physicist Paul Cooper published a paper in the American Journal of Physics suggesting that gravity trains be considered for a future transportation project.
Mathematical considerations
Under the assumption of a spherical planet with uniform density, and ignoring relativistic effects as well as friction, a gravity train has the following properties:
The duration of a trip depends only on the density of the planet and the gravitational constant, but not on the diameter of the planet.
The maximum speed is reached at the middle point of the trajectory.
For gravity trains between points which are not the antipodes of each other, the following hold:
The shortest time tunnel through a homogeneous earth is a hypocycloid; in the special |
https://en.wikipedia.org/wiki/Methoxsalen | Methoxsalen, sold under the brand name Oxsoralen among others, is a medication used to treat psoriasis, eczema, vitiligo, and some cutaneous lymphomas in conjunction with exposing the skin to ultraviolet (UVA) light from lamps or sunlight. Methoxsalen modifies the way skin cells receive the UVA radiation, allegedly clearing up the disease. Levels of individual patient PUVA exposure were originally determined using the Fitzpatrick scale. The scale was developed after patients demonstrated symptoms of phototoxicity after oral ingestion of methoxsalen followed by PUVA therapy.
Chemically, methoxsalen belongs to a class of organic natural molecules known as furanocoumarins. They consist of coumarin annulated with furan. It can also be injected and used topically.
Natural sources
In 1947, methoxsalen was isolated (under the name "ammoidin") from the plant Ammi majus, bishop's weed.
In 1970, Nielsen extracted 8-methoxypsoralen from four species of the genus Heracleum in the carrot family Apiaceae, including Heracleum mantegazzianum and Heracleum sphondylium. An additional 32 species of the genus Heracleum were found to contain 5-methoxypsoralen (bergapten) or other furanocoumarins.
Biosynthesis
The biosynthetic pathway is a combination of the shikimate pathway, which produces umbelliferone, and the mevalonate pathway.
Synthesis of umbelliferone
Umbelliferone is a phenylpropanoid and as such is synthesized from L-phenylalanine, which in turn is produced via the shikimate pathway. Phenylalanine is lysated into cinnamic acid, followed by hydroxylation by cinnamate 4-hydroxylase to yield 4-coumaric acid. The 4-coumaric acid is again hydroxylated by cinnamate/coumarate 2-hydroxylase to yield 2,4-dihydroxy-cinnamic acid (umbellic acid) followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group. Finally an intramolecular attack from the hydroxyl group of C2' to the carboxylic acid group closes the ring and forms the lactone umbelliferone.
|
https://en.wikipedia.org/wiki/Dedicated%20hosting%20service | A dedicated hosting service, dedicated server, or managed hosting service is a type of Internet hosting in which the client leases an entire server not shared with anyone else. This is more flexible than shared hosting, as organizations have full control over the server(s), including choice of operating system, hardware, etc.
There is also another level of dedicated or managed hosting commonly referred to as complex managed hosting. Complex Managed Hosting applies to both physical dedicated servers, Hybrid server and virtual servers, with many companies choosing a hybrid (combination of physical and virtual) hosting solution.
There are many similarities between standard and complex managed hosting but the key difference is the level of administrative and engineering support that the customer pays for – owing to both the increased size and complexity of the infrastructure deployment. The provider steps in to take over most of the management, including security, memory, storage and IT support. The service is primarily proactive in nature. Server administration can usually be provided by the hosting company as an add-on service. In some cases a dedicated server can offer less overhead and a larger return on investment. Dedicated servers are hosted in data centers, often providing redundant power sources and HVAC systems. In contrast to colocation, the server hardware is owned by the provider and in some cases they will provide support for operating systems or applications.
Using a dedicated hosting service offers the benefits of high performance, security, email stability, and control. Due to the relatively high price of dedicated hosting, it is mostly used by websites that receive a large volume of traffic.
Operating system support
Availability, price and employee familiarity often determines which operating systems are offered on dedicated servers. Variations of Linux and Unix (open source operating systems) are often included at no charge to the customer. Com |
https://en.wikipedia.org/wiki/Front%20velocity | In physics, front velocity is the speed at which the first rise of a pulse above zero moves forward.
In mathematics, it is used to describe the velocity of a propagating front in the solution of hyperbolic partial differential equation.
Various velocities
Associated with propagation of a disturbance are several different velocities. For definiteness, consider an amplitude modulated electromagnetic carrier wave. The phase velocity is the speed of the underlying carrier wave. The group velocity is the speed of the modulation or envelope. Initially it was thought that the group velocity coincided with the speed at which information traveled. However, it turns out that this speed can exceed the speed of light in some circumstances, causing confusion by an apparent conflict with the theory of relativity. That observation led to consideration of what constitutes a signal.
By definition, a signal involves new information or an element of 'surprise' that cannot be predicted from the wave motion at an earlier time. One possible form for a signal (at the point of emission) is:
where u(t) is the Heaviside step function. Using such a form for a signal, it can be shown, subject to the (expected) condition that the refractive index of any medium tends to one as the frequency tends to infinity, that the wave discontinuity, called the front, propagates at a speed less than or equal to the speed of light c in any medium. In fact, the earliest appearance of the front of an electromagnetic disturbance (the precursor) travels at the front velocity, which is c, no matter what the medium. However, the process always starts from zero amplitude and builds up. |
https://en.wikipedia.org/wiki/Selberg%20class | In mathematics, the Selberg class is an axiomatic definition of a class of L-functions. The members of the class are Dirichlet series which obey four axioms that seem to capture the essential properties satisfied by most functions that are commonly called L-functions or zeta functions. Although the exact nature of the class is conjectural, the hope is that the definition of the class will lead to a classification of its contents and an elucidation of its properties, including insight into their relationship to automorphic forms and the Riemann hypothesis. The class was defined by Atle Selberg in , who preferred not to use the word "axiom" that later authors have employed.
Definition
The formal definition of the class S is the set of all Dirichlet series
absolutely convergent for Re(s) > 1 that satisfy four axioms (or assumptions as Selberg calls them):
Comments on definition
The condition that the real part of μi be non-negative is because there are known L-functions that do not satisfy the Riemann hypothesis when μi is negative. Specifically, there are Maass forms associated with exceptional eigenvalues, for which the Ramanujan–Peterssen conjecture holds, and have a functional equation, but do not satisfy the Riemann hypothesis.
The condition that θ < 1/2 is important, as the θ = 1 case includes whose zeros are not on the critical line.
Without the condition there would be which violates the Riemann hypothesis.
It is a consequence of 4. that the an are multiplicative and that
Examples
The prototypical example of an element in S is the Riemann zeta function. Another example, is the L-function of the modular discriminant Δ
where and τ(n) is the Ramanujan tau function.
All known examples are automorphic L-functions, and the reciprocals of Fp(s) are polynomials in p−s of bounded degree.
The best results on the structure of the Selberg class are due to Kaczorowski and Perelli, who show that the Dirichlet L-functions (including the Riemann zeta-function |
https://en.wikipedia.org/wiki/Sephadex | Sephadex is a cross-linked dextran gel used for gel filtration. It was launched by Pharmacia in 1959, after development work by Jerker Porath and Per Flodin. The name is derived from separation Pharmacia dextran. It is normally manufactured in a bead form and most commonly used for gel filtration columns. By varying the degree of cross-linking, the fractionation properties of the gel can be altered.
These highly specialized gel filtration and chromatographic media are composed of macroscopic beads synthetically derived from the polysaccharide dextran. The organic chains are cross-linked to give a three-dimensional network having functional ionic groups attached by ether linkages to glucose units of the polysaccharide chains.
Available forms include anion and cation exchangers, as well as gel filtration resins, with varying degrees of porosity; bead sizes fall in discrete ranges between 20 and 300 µm.
Sephadex is also used for ion-exchange chromatography.
Sephadex is crosslinked with epichlorohydrin.
Applications
Sephadex is used to separate molecules by molecular weight. Sephadex is a faster alternative to dialysis (de-salting), requiring a low dilution factor (as little as 1.4:1), with high activity recoveries. Sephadex is also used for buffer exchange and the removal of small molecules during the preparation of large biomolecules, such as ampholytes, detergents, radioactive or fluorescent labels, and phenol (during DNA purification).
A special hydroxypropylated form of Sephadex resin, named Sephadex LH-20, is used for the separation and purification of small organic molecules such as steroids, terpenoids, lipids. An example of use is the purification of cholesterol.
Fractionation
Exclusion chromatography.
Fractionation Range of Globular Proteins and Dextrans (Da).
Ion-exchange chromatography.
See also
PEGylation
Size exclusion chromatography
Superose
Sepharose |
https://en.wikipedia.org/wiki/Sorghum%20%C3%97%20drummondii | Sorghum × drummondii (Sudan grass), is a hybrid-derived species of grass raised for forage and grain, native to tropical and subtropical regions of Eastern Africa. It may also be known as Sorghum bicolor × Sorghum arundinaceum after its parents. Some authorities consider all three species to be subspecies under S. bicolor.
The plant is cultivated in Southern Europe, South America, Central America, North America and Southern Asia, for forage or as a cover crop. When treated as a weed, it is known as shattercane. It is distinguished from the grain sorghum (Sorghum bicolor) by the grain (caryopsis) not being exposed at maturity. |
https://en.wikipedia.org/wiki/Soil%20crust | Soil crusts are soil surface layers that are distinct from the rest of the bulk soil, often hardened with a platy surface. Depending on the manner of formation, soil crusts can be biological or physical. Biological soil crusts are formed by communities of microorganisms that live on the soil surface whereas physical crusts are formed by physical impact such as that of raindrops.
Biological soil crusts
Biological soil crusts are communities of living organisms on the soil surface in arid- and semi-arid ecosystems. They are found throughout the world with varying species composition and cover depending on topography, soil characteristics, climate, plant community, microhabitats, and disturbance regimes. Biological soil crusts perform important ecological roles including carbon fixation, nitrogen fixation, soil stabilization, alter soil albedo and water relations, and affect germination and nutrient levels in vascular plants. They can be damaged by fire, recreational activity, grazing, and other disturbance and can require long time periods to recover composition and function. Biological soil crusts are also known as cryptogamic, microbiotic, microphytic, or cryptobiotic soils.
Physical soil crusts
Physical (as opposed to biological) soil crusts results from raindrop or trampling impacts. They are often hardened relative to uncrusted soil due to the accumulation of salts and silica. These can coexist with biological soil crusts, but have different ecological impact due to their difference in formation and composition. Physical soil crusts often reduce water infiltration, can inhibit plant establishment, and when disrupted can be eroded rapidly. |
https://en.wikipedia.org/wiki/Ballistic%20coefficient | In ballistics, the ballistic coefficient (BC, C) of a body is a measure of its ability to overcome air resistance in flight. It is inversely proportional to the negative acceleration: a high number indicates a low negative acceleration—the drag on the body is small in proportion to its mass. BC can be expressed with the units kilograms per square meter (kg/m2) or pounds per square inch (lb/in2) (where 1 lb/in2 corresponds to ).
Formulas
General
where:
Cb,Physics, ballistic coefficient as used in physics and engineering
m, mass
A, cross-sectional area
Cd, drag coefficient
, density
, characteristic body length
Ballistics
The formula for calculating the ballistic coefficient for small and large arms projectiles only is as follows:
where:
Cb,Projectile, ballistic coefficient as used in point mass trajectory from the Siacci method (less than 20 degrees).
m, mass of bullet
d, measured cross section (diameter) of projectile
i, coefficient of form
The coefficient of form, i, can be derived by 6 methods and applied differently depending on the trajectory models used: G model, Beugless/Coxe; 3 Sky Screen; 4 Sky Screen; target zeroing; Doppler radar.
Here are several methods to compute i or Cd:
where:
or
A drag coefficient can also be calculated mathematically:
where:
Cd, drag coefficient.
, density of the projectile.
v, projectile velocity at range.
π (pi) = 3.14159…
d, measured cross section (diameter) of projectile
or
From standard physics as applied to "G" models:
where:
i, coefficient of form.
CG, drag coefficient of 1.00 from any "G" model, reference drawing, projectile.
Cp, drag coefficient of the actual test projectile at range.
Commercial use
This formula is for calculating the ballistic coefficient within the small arms shooting community, but is redundant with Cb,Projectile:
where:
Cb,Smallarms, ballistic coefficient
SD, sectional density
i, coefficient of form (form factor)
History
Background
In 1537, Niccolò Tartaglia performed |
https://en.wikipedia.org/wiki/Telephone%20exchange%20names | A telephone exchange name or central office name was a distinguishing and memorable name assigned to a central office. It identified the switching system to which a telephone was connected, and facilitated the connection of telephone calls between switching systems in different localities.
While small towns and rural areas might each be served by a single exchange, large cities were served by multiple switching systems, either distributed in the community constituting multiple exchange areas, or sometimes hosted in the same building to serve a densely populated area. Central offices were usually identified by names that were locally significant. The leading letters of a central office name were used as the leading components of the telephone number representation, so that each telephone number in the area was unique. These letters were mapped to the digits of the dial, which was indicated visibly on the dial's numbering plate.
Several systematic telephone numbering plans existed in various communities, typically evolving over time as the subscriber base outgrew older numbering schemes. A widely used numbering plan was a system of using one or two letters from the central office name with four or five digits. Such systems were designated as 2L-4N or 2L-5N, or simply 2–4 and 2–5, respectively, but some large cities initially selected plans with three letters (3L-4N). In 1917, W. G. Blauvelt of AT&T proposed a mapping system that displayed three letters each with the digits 2 through 9 on the dial.
Telephone directories or other telephone number displays, such as in advertising, typically listed the telephone number showing the significant letters of the central office name in bold capital letters, followed by the digits that identified the subscriber line. On the number card of the telephone instrument, the name was typically shown in full, but only the significant letters to be dialed were capitalized, while the rest of the name was shown in lower case.
Telephone |
https://en.wikipedia.org/wiki/Bulk%20density | In materials science, bulk density, also called apparent density, is a material property defined as the mass of the many particles of the material divided by the bulk volume. Bulk volume is defined as the total volume the particles occupy, including particle's own volume, inter-particle void volume, and the particles' internal pore volume.
Bulk density is useful for materials such as powders, granules, and other "divided" solids, especially used in reference to mineral components (soil, gravel), chemical substances, pharmaceutical ingredients, foodstuff, or any other masses of corpuscular or particulate matter (particles).
Bulk density is not the same as the particle density, which is an intrinsic property of the solid and does not include the volume for voids between particles (see: density of non-compact materials).
Bulk density is an extrinsic property of a material; it can change depending on how the material is handled. For example, a powder poured into a cylinder will have a particular bulk density; if the cylinder is disturbed, the powder particles will move and usually settle closer together, resulting in a higher bulk density. For this reason, the bulk density of powders is usually reported both as "freely settled" (or "poured" density) and "tapped" density (where the tapped density refers to the bulk density of the powder after a specified compaction process, usually involving vibration of the container.)
Soil
The bulk density of soil depends greatly on the mineral make up of soil and the degree of compaction. The density of quartz is around but the (dry) bulk density of a mineral soil is normally about half that density, between . In contrast, soils rich in soil organic carbon and some friable clays tend to have lower bulk densities () due to a combination of the low-density of the organic materials themselves and increased porosity. For instance, peat soils have bulk densities from .
Bulk density of soil is usually determined from a core sampl |
https://en.wikipedia.org/wiki/Angle%20of%20arrival | The angle of arrival (AoA) of a signal is the direction from which the signal (e.g. radio, optical or acoustic) is received.
Measurement
Measurement of AoA can be done by determining the direction of propagation of a radio-frequency wave incident on an antenna array or determined from maximum signal strength during antenna rotation.
The AoA can be calculated by measuring the time difference of arrival (TDOA) between individual elements of the array.
Generally this TDOA measurement is made by measuring the difference in received phase at each element in the antenna array. This can be thought of as beamforming in reverse. In beamforming, the signal from each element is weighed to "steer" the gain of the antenna array. In AoA, the delay of arrival at each element is measured directly and converted to an AoA measurement.
Consider, for example, a two element array spaced apart by one-half the wavelength of an incoming RF wave. If a wave is incident upon the array at boresight, it will arrive at each antenna simultaneously. This will yield 0° phase-difference measured between the two antenna elements, equivalent to a 0° AoA. If a wave is incident upon the array at broadside, then a 180° phase difference will be measured between the elements, corresponding to a 90° AoA.
In optics, AoA can be calculated using interferometry.
Applications
An application of AoA is in the geolocation of cell phones. The aim is either for the cell system to report the location of a cell phone placing an emergency call or to provide a service to tell the user of the cell phone where they are. Multiple receivers on a base station would calculate the AoA of the cell phone's signal, and this information would be combined to determine the phone's location.
AoA is generally used to discover the location of pirate radio stations or of any military radio transmitter.
In submarine acoustics, AoA is used to localize objects with active or passive ranging.
Limitation
Limitations on the acc |
https://en.wikipedia.org/wiki/Recurrence%20quantification%20analysis | Recurrence quantification analysis (RQA) is a method of nonlinear data analysis (cf. chaos theory) for the investigation of dynamical systems. It quantifies the number and duration of recurrences of a dynamical system presented by its phase space trajectory.
Background
The recurrence quantification analysis (RQA) was developed in order to quantify differently appearing recurrence plots (RPs), based on the small-scale structures therein. Recurrence plots are tools which visualise the recurrence behaviour of the phase space trajectory of dynamical systems:
,
where is the Heaviside function and a predefined tolerance.
Recurrence plots mostly contain single dots and lines which are parallel to the mean diagonal (line of identity, LOI) or which are vertical/horizontal. Lines parallel to the LOI are referred to as diagonal lines and the vertical structures as vertical lines. Because an RP is usually symmetric, horizontal and vertical lines correspond to each other, and, hence, only vertical lines are considered. The lines correspond to a typical behaviour of the phase space trajectory: whereas the diagonal lines represent such segments of the phase space trajectory which run parallel for some time, the vertical lines represent segments which remain in the same phase space region for some time.
If only a time series is available, the phase space can be reconstructed by using a time delay embedding (see Takens' theorem):
where is the time series, the embedding dimension and the time delay.
The RQA quantifies the small-scale structures of recurrence plots, which present the number and duration of the recurrences of a dynamical system. The measures introduced for the RQA were developed heuristically between 1992 and 2002 (Zbilut & Webber 1992; Webber & Zbilut 1994; Marwan et al. 2002). They are actually measures of complexity. The main advantage of the recurrence quantification analysis is that it can provide useful information even for short and non-stationary d |
https://en.wikipedia.org/wiki/City%20Connection | is a 1985 platform game developed and published as an arcade video game by Jaleco. It was released in North America by Kitkorp as Cruisin'. The player controls Clarice in her Honda City hatchback and must drive over elevated roads to paint them. Clarice is pursued by police cars, which she can stun by hitting them with oil cans. The design was inspired by maze chase games like Pac-Man (1980) and Crush Roller (1981)
City Connection was ported to the Nintendo Entertainment System, MSX, and ZX Spectrum. In Japan, the game has maintained a loyal following, and the NES version is seen as a classic for the platform. It was re-released in several Jaleco game collections and services such as the Wii Virtual Console. These received mixed responses in North America, with critics disliking its simplicity, lack of replay value, and poor controls. Some felt it possessed a cute aesthetic and unique concept and was entertaining. Clarice is one of the first female protagonists in a console game.
Jaleco released a sequel, City Connection Rocket, for Japanese mobile phones in 2004.
Gameplay
In City Connection, the player controls Clarice, a blue-haired teen driving an orange Honda City hatchback, as she travels around the world in the quest of finding herself the perfect man. Clarice traverses through twelve side-scrolling stages that take place within famous locations around the world, including New York, London, and Japan. To clear these levels, the player must drive over each of the elevated highways to change their color from white to green. The car can jump over large gaps to reach higher sections of the stage.
Clarice is constantly being pursued by police cars that follow her around the stage, and must also avoid flag-waving cats that block her from moving past them. Clarice can collect and launch oil cans at police cars and traffic vehicles to temporarily stun them; ramming into them while stunned will knock them off the stage. Cats are invulnerable to oil cans, and cann |
https://en.wikipedia.org/wiki/Lamellar%20structure | In materials science, lamellar structures or microstructures are composed of fine, alternating layers of different materials in the form of lamellae. They are often observed in cases where a phase transition front moves quickly, leaving behind two solid products, as in rapid cooling of eutectic (such as solder) or eutectoid (such as pearlite) systems.
Such conditions force phases of different composition to form but allow little time for diffusion to produce those phases' equilibrium compositions. Fine lamellae solve this problem by shortening the diffusion distance between phases, but their high surface energy makes them unstable and prone to break up when annealing allows diffusion to progress. A deeper eutectic or more rapid cooling will result in finer lamellae; as the size of an individual lamellum approaches zero, the system will instead retain its high-temperature structure. Two common cases of this include cooling a liquid to form an amorphous solid, and cooling eutectoid austenite to form martensite.
In biology, normal adult bones possess a lamellar structure which may be disrupted by some diseases. |
https://en.wikipedia.org/wiki/Defeminization | In developmental biology and zoology, defeminization is an aspect of the process of sexual differentiation by which a potential female-specific structure, function, or behavior is changed by one of the processes of male development.
See also
Sexual differentiation
Defeminization and masculinization
Virilization
Feminization |
https://en.wikipedia.org/wiki/Thermal%20decomposition | Thermal decomposition (or thermolysis) is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction.
Decomposition temperature definition
A simple substance (like water) may exist in equilibrium with its thermal decomposition products, effectively halting the decomposition. The equilibrium fraction of decomposed molecules increases with the temperature.
Since thermal decomposition is a kinetic process, the observed temperature of its beginning in most instances will be a function of the experimental conditions and sensitivity of the experimental setup. For rigorous depiction of the process, the use of thermokinetic modeling is recommended.
Examples
Calcium carbonate (limestone or chalk) decomposes into calcium oxide and carbon dioxide when heated. The chemical reaction is as follows:
CaCO3 → CaO + CO2
The reaction is used to make quick lime, which is an industrially important product.
Another example of thermal decomposition is 2Pb(NO3)2 → 2PbO + O2 + 4NO2.
Some oxides, especially of weakly electropositive metals decompose when heated to high enough temperature. A classical example is the decomposition of mercuric oxide to give oxygen and mercury metal. The reaction was used by Joseph Priestley to prepare samples of gaseous oxygen for the first time.
When water is heated to well over 2000 °C, a small percentage of it will decompose into OH, monatomic oxygen, monatomic hydrogen, O2, and H2.
The compound with the highest known decomposition temperature is carbon monoxide at ≈3870 °C (≈7000 °F).
Decomposition of nitrates, nitrites and ammonium compounds
Ammonium dichromate on heating yields nitro |
https://en.wikipedia.org/wiki/Faint%20young%20Sun%20paradox | The faint young Sun paradox or faint young Sun problem describes the apparent contradiction between observations of liquid water early in Earth's history and the astrophysical expectation that the Sun's output would be only 70 percent as intense during that epoch as it is during the modern epoch. The paradox is this: with the young sun's output at only 70 percent of its current output, early Earth would be expected to be completely frozenbut early Earth seems to have had liquid water and supported life.
The issue was raised by astronomers Carl Sagan and George Mullen in 1972.
Proposed resolutions of this paradox have taken into account greenhouse effects, changes to planetary albedo, astrophysical influences, or combinations of these suggestions. It turned out that the greenhouse gas carbon dioxide contributed most.
Solar evolution
Models of stellar structure, esp. the standard solar model were already sufficiently evolved at that time to predict a brightening: It is due to the decrease in the number of particles per unit mass due to nuclear fusion in the Sun's core, from four protons and electrons each to one helium nucleus and two electrons. Fewer particles would exert less pressure. A collapse under the enormous gravity is prevented by an increase in temperature, which is both cause and effect of a higher rate of nuclear fusion. More recent modeling studies have shown that the Sun is currently 1.4 times brighter today than it was 4.6 billion years ago (Ga), and that the brightening has accelerated considerably. At the surface of the Sun, more fusion power means a higher solar luminosity (via slight increases in temperature and radius), which on Earth is termed radiative forcing.
Greenhouse gas solutions
Ammonia as a greenhouse gas
Sagan and Mullen even suggested during their descriptions of the paradox that it might be solved by high concentrations of ammonia gas, NH3. However, it has since been shown that while ammonia is an effective greenhouse gas, it i |
https://en.wikipedia.org/wiki/Ligand%20%28biochemistry%29 | In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from Latin ligare, which means 'to bind'. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. The binding typically results in a change of conformational isomerism (conformation) of the target protein. In DNA-ligand binding studies, the ligand can be a small molecule, ion, or protein which binds to the DNA double helix. The relationship between ligand and binding partner is a function of charge, hydrophobicity, and molecular structure.
Binding occurs by intermolecular forces, such as ionic bonds, hydrogen bonds and Van der Waals forces. The association or docking is actually reversible through dissociation. Measurably irreversible covalent bonding between a ligand and target molecule is atypical in biological systems. In contrast to the definition of ligand in metalorganic and inorganic chemistry, in biochemistry it is ambiguous whether the ligand generally binds at a metal site, as is the case in hemoglobin. In general, the interpretation of ligand is contextual with regards to what sort of binding has been observed.
Ligand binding to a receptor protein alters the conformation by affecting the three-dimensional shape orientation. The conformation of a receptor protein composes the functional state. Ligands include substrates, inhibitors, activators, signaling lipids, and neurotransmitters. The rate of binding is called affinity, and this measurement typifies a tendency or strength of the effect. Binding affinity is actualized not only by host–guest interactions, but also by solvent effects that can play a dominant, steric role which drives non-covalent binding in solution. The solvent provides a chemical environment for the ligand and receptor to adapt, and thus accept or reject each other as partners.
Radioligands are radioisotope labeled |
https://en.wikipedia.org/wiki/Ornidazole | Ornidazole is an antibiotic used to treat protozoan infections. A synthetic nitroimidazole, it is commercially obtained from an acid-catalyzed reaction between 2-methyl-5-nitroimidazole and epichlorohydrin.
Antimicrobial spectrum is similar to that of metronidazole and is more well tolerated; however there are concerns of lower relative efficacy.
It was first introduced for treating trichomoniasis before being recognized for its broad anti-protozoan and anti-anaerobic-bacterial capacities. has also been investigated for use in Crohn's disease after bowel resection. |
https://en.wikipedia.org/wiki/Harvard%20Mark%20II | The Harvard Mark II, also known as the Aiken Relay Calculator, was an electromechanical computer built under the direction of Howard Aiken at Harvard University, completed in 1947. It was financed by the United States Navy and used for ballistic calculations at Naval Proving Ground Dahlgren. Howard Aiken and Grace Hopper worked together to build and program the Mark II.
Overview
The contract to build the Mark II was signed with Harvard in February 1945, after the successful demonstration of the Mark I in 1944. It was completed and debugged in 1947, and delivered to the US Navy Proving Ground at Dahlgren, Virginia in March 1948, becoming fully operational by the end of that year.
The Mark II was constructed with high-speed electromagnetic relays instead of the electro-mechanical counters used in the Mark I, making it much faster than its predecessor. It weighed and occupied over of floor space. Its addition time was 0.125 seconds (8 Hz) and the multiplication time was 0.750 seconds. This was a factor of 2.6 faster for addition and a factor of 8 faster for multiplication compared to the Mark I. It was the second machine (after the Bell Labs Relay Calculator) to have floating-point hardware. A unique feature of the Mark II is that it had built-in hardware for several functions such as the reciprocal, square root, logarithm, exponential, and some trigonometric functions. These took between five and twelve seconds to execute. Additionally, the Mark II was actually composed of two sub-computers that could either work in tandem or operate on separate functions, to cross-check results and debug malfunctions.
The Mark I and Mark II were not stored-program computers – they read instructions of the program one at a time from a tape and executed them. The Mark II had a peculiar programming method that was devised to ensure that the contents of a register were available when needed. The tape containing the program could encode only eight instructions, so what a particular |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.