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wait(m, cv);
// Temporarily prevent any other thread on any core from doing
// operations on m or cv.
// release(m) // Atomically release lock "m" so other
// // code using this concurrent data
// // can operate, move this thread to cv's
// // wait-queue so that it will be notified
// // someti... | Monitor (synchronization) | Wikipedia | 503 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Release the mutex so that notified thread(s) and others can enter their critical
// sections.
release(m);
Solving the bounded producer/consumer problem
Having introduced the usage of condition variables, let us use it to revisit and solve the classic bounded producer/consumer problem. The classic solution is to u... | Monitor (synchronization) | Wikipedia | 479 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Method representing each consumer thread's behavior:
public method consumer() {
while (true) {
// Acquire "queueLock" for the initial predicate check.
queueLock.acquire();
// Critical section that checks if the queue is non-empty.
while (queue.isEmpty()) {
// Release ... | Monitor (synchronization) | Wikipedia | 320 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
A variant of this solution could use a single condition variable for both producers and consumers, perhaps named "queueFullOrEmptyCV" or "queueSizeChangedCV". In this case, more than one condition is associated with the condition variable, such that the condition variable represents a weaker condition than the conditi... | Monitor (synchronization) | Wikipedia | 459 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Critical section that checks if the queue is non-full.
while (queue.isFull()) {
// Release "queueLock", enqueue this thread onto "queueFullOrEmptyCV" and sleep this thread.
wait(queueLock, queueFullOrEmptyCV);
// When this thread is awoken, re-acquire "queueLock" for the n... | Monitor (synchronization) | Wikipedia | 512 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Go off and do something with the task.
doStuff(myTask);
}
}
Synchronization primitives
Monitors are implemented using an atomic read-modify-write primitive and a waiting primitive. The read-modify-write primitive (usually test-and-set or compare-and-swap) is usually in the form of a memory-locking instr... | Monitor (synchronization) | Wikipedia | 409 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Get all of the registers of the currently-running process.
// For Program Counter (PC), we will need the instruction location of
// the "resume" label below. Getting the register values is platform-dependent and may involve
// reading the current stack frame, JMP/CALL instructions, etc. (The details ar... | Monitor (synchronization) | Wikipedia | 408 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Thread sleep method:
// On current CPU core, a synchronous context switch to another thread without putting
// the current thread on the ready queue.
// Must be holding "threadingSystemBusy" and disabled interrupts so that this method
// doesn't get interrupted by the thread-switching timer which would call contextS... | Monitor (synchronization) | Wikipedia | 491 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
public method wait(Mutex m, ConditionVariable c) {
// Internal spin-lock while other threads on any core are accessing this object's
// "held" and "threadQueue", or "readyQueue".
while (testAndSet(threadingSystemBusy)) {}
// N.B.: "threadingSystemBusy" is now true.
// System call to disable int... | Monitor (synchronization) | Wikipedia | 318 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
public method signal(ConditionVariable c) {
// Internal spin-lock while other threads on any core are accessing this object's
// "held" and "threadQueue", or "readyQueue".
while (testAndSet(threadingSystemBusy)) {}
// N.B.: "threadingSystemBusy" is now true.
// System call to disable interrupts... | Monitor (synchronization) | Wikipedia | 285 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
public method broadcast(ConditionVariable c) {
// Internal spin-lock while other threads on any core are accessing this object's
// "held" and "threadQueue", or "readyQueue".
while (testAndSet(threadingSystemBusy)) {}
// N.B.: "threadingSystemBusy" is now true.
// System call to disable interru... | Monitor (synchronization) | Wikipedia | 507 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
if (held) {
// Put "currentThread" on this lock's queue so that it will be
// considered "sleeping" on this lock.
// Note that "currentThread" still needs to be handled by threadSleep().
readyQueue.remove(currentThread);
blockingThreads.enqueue(currentThread);... | Monitor (synchronization) | Wikipedia | 420 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
Blocking condition variables
The original proposals by C. A. R. Hoare and Per Brinch Hansen were for blocking condition variables. With a blocking condition variable, the signaling thread must wait outside the monitor (at least) until the signaled thread relinquishes occupancy of the monitor by either returning or by a... | Monitor (synchronization) | Wikipedia | 479 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
signal and return:
if there is a thread waiting on .q
select and remove one such thread t from .q
(t is called "the signaled thread")
restart t
(so t will occupy the monitor next)
else
schedule
return from the method
In either case ("signal and urgent wait" ... | Monitor (synchronization) | Wikipedia | 398 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
monitor class SharedStack {
private const capacity := 10
private int[capacity] A
private int size := 0
invariant 0 <= size and size <= capacity
private BlockingCondition theStackIsNotEmpty /* associated with 0 < size and size <= capacity */
private BlockingCondition theStackIsNotFull /* as... | Monitor (synchronization) | Wikipedia | 508 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
The meaning of various operations are given here. (We assume that each operation runs in mutual exclusion to the others; thus restarted threads do not begin executing until the operation is complete.)
enter the monitor:
enter the method
if the monitor is locked
add this thread to e
block t... | Monitor (synchronization) | Wikipedia | 487 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
In this example, the condition being waited for is a function of the amount to be withdrawn, so it is impossible for a depositing thread to know that it made such a condition true. It makes sense in this case to allow each waiting thread into the monitor (one at a time) to check if its assertion is true.
Implicit cond... | Monitor (synchronization) | Wikipedia | 477 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
A number of libraries have been written that allow monitors to be constructed in languages that do not support them natively. When library calls are used, it is up to the programmer to explicitly mark the start and end of code executed with mutual exclusion. Pthreads is one such library. | Monitor (synchronization) | Wikipedia | 57 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
The bacterial capsule is a large structure common to many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
The capsule—which ca... | Bacterial capsule | Wikipedia | 497 | 1368466 | https://en.wikipedia.org/wiki/Bacterial%20capsule | Biology and health sciences | Basic anatomy | Biology |
Diversity
The capsule is found most commonly among gram-negative bacteria:
Escherichia coli (in some strains)
Neisseria meningitidis
Klebsiella pneumoniae
Haemophilus influenzae
Pseudomonas aeruginosa
Salmonella
Acinetobacter baumannii
However, some gram-positive bacteria may also have a capsule:
Bacillus meg... | Bacterial capsule | Wikipedia | 460 | 1368466 | https://en.wikipedia.org/wiki/Bacterial%20capsule | Biology and health sciences | Basic anatomy | Biology |
Use in vaccination
Vaccination using capsular material is effective against some organisms (e.g., H. influenzae type b, S. pneumoniae, and N. meningitidis). However, polysaccharides are not highly antigenic, especially in children, so many capsular vaccines contain polysaccharides conjugated with protein carriers, suc... | Bacterial capsule | Wikipedia | 107 | 1368466 | https://en.wikipedia.org/wiki/Bacterial%20capsule | Biology and health sciences | Basic anatomy | Biology |
The Mangla Dam () is a multipurpose dam situated on the Jhelum River, lying in the Mirpur District of Azad Kashmir and the Jhelum District in Punjab, Pakistan. It is the sixth-largest dam in the world. The village of Mangla, which sits at the mouth of the dam, serves as its namesake. In November 1961, the project's sel... | Mangla Dam | Wikipedia | 414 | 1368943 | https://en.wikipedia.org/wiki/Mangla%20Dam | Technology | Dams | null |
Reservoir
The dam was constructed between 1961 and 1965 across the Jhelum River and Poonch River in the Mirpur District of Kashmir, about southeast of the capital city of Islamabad. The Mangla Dam components include a reservoir, main embankment, intake embankment, main spillway, emergency spillway, intake structures, ... | Mangla Dam | Wikipedia | 414 | 1368943 | https://en.wikipedia.org/wiki/Mangla%20Dam | Technology | Dams | null |
Power house
The powerhouse, which consists of turbines, generators, and transformers, has been constructed at the toe of an intake embankment at the ground surface elevation of 865 feet SPD. The water to the powerhouse is supplied through five steel-lined tunnels of 30/26 feet diameter. Each tunnel is designed to feed... | Mangla Dam | Wikipedia | 348 | 1368943 | https://en.wikipedia.org/wiki/Mangla%20Dam | Technology | Dams | null |
Displacement & Resettlement
The Government of Pakistan had agreed to pay royalties to the Government of AJK (Azad Jammu and Kashmir) for the use of the water and electricity generated by the dam. Pakistan initially committed to supplying free electricity to the entire region of Azad Kashmir and providing complimentary... | Mangla Dam | Wikipedia | 496 | 1368943 | https://en.wikipedia.org/wiki/Mangla%20Dam | Technology | Dams | null |
On 1 September 2013, the water level in Mangla Dam reached a record height of 1237.15 feet against the maximum conservation level of 1242 feet. Radio Pakistan reported that "the water level in Mangla Dam has attained the maximum height of 1237.15 feet in the history and it is still increasing."
Mangla Dam Raising Proj... | Mangla Dam | Wikipedia | 493 | 1368943 | https://en.wikipedia.org/wiki/Mangla%20Dam | Technology | Dams | null |
Degrees Brix (symbol °Bx) is a measure of the dissolved solids in a liquid, and is commonly used to measure dissolved sugar content of a solution. One degree Brix is 1 gram of sucrose in 100 grams of solution and represents the strength of the solution as percentage by mass. If the solution contains dissolved solids ot... | Brix | Wikipedia | 503 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
Equipped with one of these tables, a brewer wishing to know how much sugar was in his wort could measure its specific gravity and enter that specific gravity into the Plato table to obtain °Plato, which is the concentration of sucrose by percentage mass. Similarly, a vintner could enter the specific gravity of his must... | Brix | Wikipedia | 472 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
Also note that the tables in use today are not those published by Brix or Plato. Those workers measured true specific gravity reference to water at 4 °C using, respectively, 17.5 °C and 20 °C, as the temperature at which the density of a sucrose solution was measured. Both NBS and ASBC converted to apparent specific gr... | Brix | Wikipedia | 500 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
Another accurate (R2=0.999 999 97) and simpler formula is:
The above formulas should not be used outside the range 1.00000 to 1.17874 SG (0 to 40 °Bx).
The Plato scale can be approximated with a mean average error of less than 0.02°P with the following equation:
or with even higher accuracy (average error less than ... | Brix | Wikipedia | 308 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
where is the refractive index measured at the wavelength of the sodium D line (589.3 nm) at 20 °C. Temperature is important as refractive index changes dramatically with temperature. Many refractometers have built in "Automatic Temperature Compensation" (ATC), which is based on knowledge of the way the refractive inde... | Brix | Wikipedia | 498 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
Brix measurements are also used in the dairy industry to measure the quality of colostrum given to newborn calves, goats, and sheep.
Modern optical Brix meters are divided into two categories. In the first are the Abbe-based instruments in which a drop of the sample solution is placed on a prism; the result is obser... | Brix | Wikipedia | 368 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
Brix and actual dissolved solids content
When a sugar solution is measured by refractometer or density meter, the °Bx or °P value obtained by entry into the appropriate table only represents the amount of dry solids dissolved in the sample if the dry solids are exclusively sucrose. This is seldom the case. Grape juice ... | Brix | Wikipedia | 444 | 1369226 | https://en.wikipedia.org/wiki/Brix | Physical sciences | Concentration | Basics and measurement |
A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with two neutrons, depending on the isotope, held together by the strong force. Unlike for hydrogen, a closed-form solution to the Schrödinger equatio... | Helium atom | Wikipedia | 406 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
which implies that one should find solutions for where is a general combined spatial wavefunction. This energy, however, is not degenerate with multiplicity given by the dimension of the space of combined spin states because of a symmetrization postulate, which requires that physical solutions for identical fermions ... | Helium atom | Wikipedia | 493 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
as per symmetrization and total spin number requirement. It is observed that triplet states are symmetric and singlet states are antisymmetric. Since the total wavefunction is antisymmetric, a symmetric spatial wavefunction can only be paired with antisymmetric wavefunction and vice versa. Hence orthohelium (triplet st... | Helium atom | Wikipedia | 481 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
Since all spin interaction terms between the four components of in the above (scalar) Hamiltonian are neglected (e.g. an external magnetic field, or relativistic effects, like angular momentum coupling), the four Schrödinger equations can be solved independently. This is identical to the previously discussed method of... | Helium atom | Wikipedia | 440 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
Note that all wavefunction obtained thus far cannot be separated into wavefunctions of each particle (even for electrons with identical and where wavefunction is because then, the spin of the electrons are in a superposition of different spin states: and from ) i.e. the wavefunctions are always in superposition of... | Helium atom | Wikipedia | 510 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
where is a screening constant and the quantity is the effective charge. The potential is a Coulomb interaction, so the corresponding individual electron energies are given by
and the corresponding spatial wave function is given by
If Ze was 1.70, that would make the expression above for the ground state energy agree... | Helium atom | Wikipedia | 424 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
In general, for (1s)(nl) state, in first order perturbation theory:with:where I is known as direct integral and J is known as exchange integral or exchange energy. If the combined spatial wavefunction is symmetric, its energy level has the + symbol in , whereas for the antisymmetric combined spatial wavefunction, has ... | Helium atom | Wikipedia | 377 | 20191692 | https://en.wikipedia.org/wiki/Helium%20atom | Physical sciences | s-Block | Chemistry |
The aquaculture of salmonids is the farming and harvesting of salmonid fish under controlled conditions for both commercial and recreational purposes. Salmonids (particularly salmon and rainbow trout), along with carp and tilapia, are the three most important fish groups in aquaculture. The most commonly commercially f... | Aquaculture of salmonids | Wikipedia | 504 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Norway produces 33% of the world's farmed salmonids, and Chile produces 31%. The coastlines of these countries have suitable water temperatures and many areas well protected from storms. Chile is close to large forage fisheries which supply fish meal for salmon aquaculture. Scotland and Canada are also significant prod... | Aquaculture of salmonids | Wikipedia | 314 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
An alternative method to hatching in freshwater tanks is to use spawning channels. These are artificial streams, usually parallel to an existing stream with concrete or rip-rap sides and gravel bottoms. Water from the adjacent stream is piped into the top of the channel, sometimes via a header pond to settle out sedi... | Aquaculture of salmonids | Wikipedia | 441 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
A second emerging wave in aquaculture is the development of copper alloys as netting materials. Copper alloys have become important netting materials because they are antimicrobial (i.e., they destroy bacteria, viruses, fungi, algae, and other microbes), so they prevent biofouling (i.e., the undesirable accumulation, ... | Aquaculture of salmonids | Wikipedia | 498 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
On a dry-dry basis, 2–4 kg of wild-caught fish are needed to produce 1 kg of salmon. The ratio may be reduced if non-fish sources are added. Wild salmon require about 10 kg of forage fish to produce 1 kg of salmon, as part of the normal trophic level energy transfer. The difference between the two numbers is related to... | Aquaculture of salmonids | Wikipedia | 380 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
An older method of harvesting is to use a sweep net, which operates a bit like a purse seine net. The sweep net is a big net with weights along the bottom edge. It is stretched across the pen with the bottom edge extending to the bottom of the pen. Lines attached to the bottom corners are raised, herding some fish into... | Aquaculture of salmonids | Wikipedia | 373 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Currently, much controversy exists about the ecological and health impacts of intensive salmonid aquaculture. Of particular concern are the impacts on wild salmonids and other marine life and on the incomes of commercial salmonid fishermen. However, the 'enhanced' production of salmon juveniles – which for instance lea... | Aquaculture of salmonids | Wikipedia | 324 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
In 1984, infectious salmon anemia (ISAv) was discovered in Norway in an Atlantic salmon hatchery. Eighty percent of the fish in the outbreak died. ISAv, a viral disease, is now a major threat to the viability of Atlantic salmon farming. It is now the first of the diseases classified on List One of the European Commissi... | Aquaculture of salmonids | Wikipedia | 512 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
In the mid 1980s to the 1990s, bacterial kidney disease (BKD) caused by Renibacterium salmoninarum heavily impacted Chinook hatcheries in Idaho. The disease causes granulomatous inflammation that can lead to abscesses in the liver, spleen, and kidneys.
Pollution and contaminants
Salmonid farms are typically sited in m... | Aquaculture of salmonids | Wikipedia | 357 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
A 2004 study, reported in Science, analysed farmed and wild salmon for organochlorine contaminants. They found the contaminants were higher in farmed salmon. Within the farmed salmon, European (particularly Scottish) salmon had the highest levels, and Chilean salmon the lowest. The FDA and Health Canada have establish... | Aquaculture of salmonids | Wikipedia | 510 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Pollutants or toxins introduced by pisciculturists
In 2006, eight Norwegian salmon producers were caught in unauthorized and unlabeled use of nitrite in smoked and cured salmon. Norway applies EU regulations on food additives, according to which nitrite is allowed as a food additive in certain types of meat, but not fi... | Aquaculture of salmonids | Wikipedia | 436 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including C. clemensi and C. rogercresseyi, can cause deadly infestations of both farm-grown and wild salmon. Sea lice are naturally occurring and abundant ectoparasites which feed on mucus, blood, and skin, and migrate and latch onto the skin ... | Aquaculture of salmonids | Wikipedia | 488 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
A 2010 study that made the first use of sea lice count and fish production data from all salmon farms on the Broughton Archipelago found no correlation between the farm lice counts and wild salmon survival.
The authors conclude that the 2002 stock collapse was not caused by the farm sea lice population:
although the f... | Aquaculture of salmonids | Wikipedia | 454 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Impact on wild predatory species
Sea cages can attract a variety of wild predators which can sometimes become entangled in associated netting, leading to injury or death. In Tasmania, Australian salmon-farming sea cages have entangled white-bellied sea eagles. This has prompted one company, Huon Aquaculture, to sponso... | Aquaculture of salmonids | Wikipedia | 501 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Land-raised salmon
Recirculating aquaculture systems make it possible to farm salmon entirely on land, which as of 2019 is an ongoing initiative in the industry. However, large farmed salmon companies such as Mowi and Cermaq were not investing in such systems beyond the hatchery stage. In the United States, a major in... | Aquaculture of salmonids | Wikipedia | 484 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Many Atlantic salmon escape from cages at sea. Those salmon that further breed tend to lessen the genetic diversity of the species leading to lower survival rates, and lower catch rates. On the West Coast of North America, the non-native salmon could be an invasive threat, especially in Alaska and parts of Canada. This... | Aquaculture of salmonids | Wikipedia | 295 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Steelhead are raised in many countries throughout the world. Since the 1950s, production has grown exponentially, particularly in Europe and recently in Chile. Worldwide, in 2007, 604,695 tonnes of farmed steelhead were harvested, with a value of $2.59 billion. The largest producer is Chile. In Chile and Norway, the oc... | Aquaculture of salmonids | Wikipedia | 485 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Worldwide, in 2007, 115,376 tonnes of farmed Coho salmon were harvested with a value of $456 million. Chile, with about 90 percent of world production, is the primary producer with Japan and Canada producing the rest.
Chinook salmon
Chinook salmon are the state fish of Oregon, and are known as "king salmon" because o... | Aquaculture of salmonids | Wikipedia | 460 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Timeline
1527: The life history of the Atlantic salmon is described by Hector Boece of the University of Aberdeen, Scotland.
1763: Fertilization trials for Atlantic salmon take place in Germany. Later biologists refined these in Scotland and France.
1854: Salmon spawing beds and rearing ponds built along the bank of... | Aquaculture of salmonids | Wikipedia | 507 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
In popular culture
Chapter 14 of Paul Torday's 2007 novel Salmon Fishing in the Yemen includes a description of a visit to the "McSalmon Aqua Farms" where salmon are raised caged in a sea loch in Scotland. | Aquaculture of salmonids | Wikipedia | 46 | 22726521 | https://en.wikipedia.org/wiki/Aquaculture%20of%20salmonids | Technology | Aquaculture | null |
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which... | Visual perception | Wikipedia | 500 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
The major problem in visual perception is that what people see is not simply a translation of retinal stimuli (i.e., the image on the retina), with the brain altering the basic information taken in. Thus people interested in perception have long struggled to explain what visual processing does to create what is actuall... | Visual perception | Wikipedia | 455 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Alhazen (965 – 1040) carried out many investigations and experiments on visual perception, extended the work of Ptolemy on binocular vision, and commented on the anatomical works of Galen. He was the first person to explain that vision occurs when light bounces on an object and then is directed to one's eyes.
Leonard... | Visual perception | Wikipedia | 458 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Another type of unconscious inference hypothesis (based on probabilities) has recently been revived in so-called Bayesian studies of visual perception. Proponents of this approach consider that the visual system performs some form of Bayesian inference to derive a perception from sensory data. However, it is not clear ... | Visual perception | Wikipedia | 483 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
It can also be noted that there are different types of eye movements: fixational eye movements (microsaccades, ocular drift, and tremor), vergence movements, saccadic movements and pursuit movements. Fixations are comparably static points where the eye rests. However, the eye is never completely still, and gaze positio... | Visual perception | Wikipedia | 480 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Some studies tend to show that rather than the uniform global image, some particular features and regions of interest of the objects are key elements when the brain needs to recognise an object in an image. In this way, the human vision is vulnerable to small particular changes to the image, such as disrupting the edge... | Visual perception | Wikipedia | 486 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Marr's 2D sketch assumes that a depth map is constructed, and that this map is the basis of 3D shape perception. However, both stereoscopic and pictorial perception, as well as monocular viewing, make clear that the perception of 3D shape precedes, and does not rely on, the perception of the depth of points. It is not ... | Visual perception | Wikipedia | 340 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Transduction is the process through which energy from environmental stimuli is converted to neural activity. The retina contains three different cell layers: photoreceptor layer, bipolar cell layer, and ganglion cell layer. The photoreceptor layer where transduction occurs is farthest from the lens. It contains photore... | Visual perception | Wikipedia | 307 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
Opponent process
Transduction involves chemical messages sent from the photoreceptors to the bipolar cells to the ganglion cells. Several photoreceptors may send their information to one ganglion cell. There are two types of ganglion cells: red/green and yellow/blue. These neurons constantly fire—even when not stimula... | Visual perception | Wikipedia | 355 | 21280496 | https://en.wikipedia.org/wiki/Visual%20perception | Biology and health sciences | Nervous system | null |
In engineering, a mechanism is a device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which may include Gears and gear trains; Belts and chain drives; cams and followers; Linkages; Friction devices, such as brakes or clutche... | Mechanism (engineering) | Wikipedia | 507 | 21280576 | https://en.wikipedia.org/wiki/Mechanism%20%28engineering%29 | Technology | Machinery and tools: General | null |
Lower pair: A lower pair is an ideal joint that has surface contact between the pair of elements, as in the following cases:
A revolute pair, or hinged joint, requires that a line in the moving body remain co-linear with a line in the fixed body, and a plane perpendicular to this line in the moving body must maintain ... | Mechanism (engineering) | Wikipedia | 510 | 21280576 | https://en.wikipedia.org/wiki/Mechanism%20%28engineering%29 | Technology | Machinery and tools: General | null |
While all mechanisms in a mechanical system are three-dimensional, they can be analysed using plane geometry if the movement of the individual components is constrained so that all point trajectories are parallel or in a series connection to a plane. In this case the system is called a planar mechanism. The kinematic a... | Mechanism (engineering) | Wikipedia | 412 | 21280576 | https://en.wikipedia.org/wiki/Mechanism%20%28engineering%29 | Technology | Machinery and tools: General | null |
A mechanism in which a body moves through a general spatial movement is called a spatial mechanism. An example is the RSSR linkage, which can be viewed as a four-bar linkage in which the hinged joints of the coupler link are replaced by rod ends, also called spherical joints or ball joints. The rod ends let the input a... | Mechanism (engineering) | Wikipedia | 511 | 21280576 | https://en.wikipedia.org/wiki/Mechanism%20%28engineering%29 | Technology | Machinery and tools: General | null |
Flexure bearings (also known as flexure joints) are a subset of compliant mechanisms that produce a geometrically well-defined motion (rotation) on application of a force.
Cam and follower mechanisms
A cam and follower mechanism is formed by the direct contact of two specially shaped links. The driving link is calle... | Mechanism (engineering) | Wikipedia | 418 | 21280576 | https://en.wikipedia.org/wiki/Mechanism%20%28engineering%29 | Technology | Machinery and tools: General | null |
The thin disk is a structural component of spiral and S0-type galaxies, composed of stars, gas and dust. It is the main non-centre (e.g. galactic bulge) density, of such matter. That of the Milky Way is thought to have a scale height of around in the vertical axis perpendicular to the disk, and a scale length of aroun... | Thin disk | Wikipedia | 317 | 35541901 | https://en.wikipedia.org/wiki/Thin%20disk | Physical sciences | Basics_2 | Astronomy |
Grain size (or particle size) is the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. This is different from the crystallite size, which refers to the size of a single crystal inside a particle or grain. A single grain can... | Grain size | Wikipedia | 444 | 31367277 | https://en.wikipedia.org/wiki/Grain%20size | Physical sciences | Sedimentology | Earth science |
A spinneret is a device used to extrude a polymer solution or polymer melt to form fibers. Streams of viscous polymer exit via the spinneret into air or liquid leading to a phase inversion which allows the polymer to solidify. The individual polymer chains tend to align in the fiber because of viscous flow. This airstr... | Spinneret (polymers) | Wikipedia | 188 | 20203982 | https://en.wikipedia.org/wiki/Spinneret%20%28polymers%29 | Technology | Spinning | null |
Health and usage monitoring systems (HUMS) is a generic term given to activities that utilize data collection and analysis techniques to help ensure availability, reliability and safety of vehicles. Activities similar to, or sometimes used interchangeably with, HUMS include condition-based maintenance (CBM) and operati... | Health and usage monitoring systems | Wikipedia | 262 | 32861742 | https://en.wikipedia.org/wiki/Health%20and%20usage%20monitoring%20systems | Technology | Aircraft components | null |
In agriculture, the yield is a measurement of the amount of a crop grown, or product such as wool, meat or milk produced, per unit area of land. The seed ratio is another way of calculating yields.
Innovations, such as the use of fertilizer, the creation of better farming tools, new methods of farming and improved cro... | Crop yield | Wikipedia | 430 | 2792729 | https://en.wikipedia.org/wiki/Crop%20yield | Technology | Basics_3 | null |
Seed multiplication ratio
The seed multiplication ratio is the ratio between the investment in seed versus the yield. For example, if three grains are harvested for each grain seeded, the resulting multiplication ratio is 1:3, which is considered by some agronomists as the minimum required to sustain human life. One of... | Crop yield | Wikipedia | 334 | 2792729 | https://en.wikipedia.org/wiki/Crop%20yield | Technology | Basics_3 | null |
Quantum mechanics is the study of matter and its interactions with energy on the scale of atomic and subatomic particles. By contrast, classical physics explains matter and energy only on a scale familiar to human experience, including the behavior of astronomical bodies such as the moon. Classical physics is still use... | Introduction to quantum mechanics | Wikipedia | 460 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
The seeds of the quantum revolution appear in the discovery by J.J. Thomson in 1897 that cathode rays were not continuous but "corpuscles" (electrons). Electrons had been named just six years earlier as part of the emerging theory of atoms. In 1900, Max Planck, unconvinced by the atomic theory, discovered that he neede... | Introduction to quantum mechanics | Wikipedia | 471 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Einstein then predicted that the electron velocity would increase in direct proportion to the light frequency above a fixed value that depended upon the metal. Here the idea is that energy in energy-quanta depends upon the light frequency; the energy transferred to the electron comes in proportion to the light frequenc... | Introduction to quantum mechanics | Wikipedia | 510 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Throughout the first and the modern era of quantum mechanics the concept that classical mechanics must be valid macroscopically constrained possible quantum models. This concept was formalized by Bohr in 1923 as the correspondence principle. It requires quantum theory to converge to classical limits.
A related concept ... | Introduction to quantum mechanics | Wikipedia | 456 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
In 1927 at Bell Labs, Clinton Davisson and Lester Germer fired slow-moving electrons at a crystalline nickel target which showed a diffraction pattern indicating wave nature of electron whose theory was fully explained by Hans Bethe. A similar experiment by George Paget Thomson and Alexander Reid, firing electrons at t... | Introduction to quantum mechanics | Wikipedia | 512 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
If the source intensity is turned down, the same interference pattern will slowly build up, one "count" or particle (e.g. photon or electron) at a time. The quantum system acts as a wave when passing through the double slits, but as a particle when it is detected. This is a typical feature of quantum complementarity: a... | Introduction to quantum mechanics | Wikipedia | 411 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Heisenberg gave, as an illustration, the measurement of the position and momentum of an electron using a photon of light. In measuring the electron's position, the higher the frequency of the photon, the more accurate is the measurement of the position of the impact of the photon with the electron, but the greater is t... | Introduction to quantum mechanics | Wikipedia | 379 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
For example, before a photon actually "shows up" on a detection screen it can be described only with a set of probabilities for where it might show up. When it does appear, for instance in the CCD of an electronic camera, the time and space where it interacted with the device are known within very tight limits. However... | Introduction to quantum mechanics | Wikipedia | 452 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
In 1924, Wolfgang Pauli proposed a new quantum degree of freedom (or quantum number), with two possible values, to resolve inconsistencies between observed molecular spectra and the predictions of quantum mechanics. In particular, the spectrum of atomic hydrogen had a doublet, or pair of lines differing by a small amou... | Introduction to quantum mechanics | Wikipedia | 407 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
An early landmark in the study of entanglement was the Einstein–Podolsky–Rosen (EPR) paradox, a thought experiment proposed by Albert Einstein, Boris Podolsky and Nathan Rosen which argues that the description of physical reality provided by quantum mechanics is incomplete. In a 1935 paper titled "Can Quantum-Mechanica... | Introduction to quantum mechanics | Wikipedia | 418 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
The Irish physicist John Stewart Bell carried the analysis of quantum entanglement much further. He deduced that if measurements are performed independently on the two separated particles of an entangled pair, then the assumption that the outcomes depend upon hidden variables within each half implies a mathematical con... | Introduction to quantum mechanics | Wikipedia | 457 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Quantum electrodynamics (QED) is the name of the quantum theory of the electromagnetic force. Understanding QED begins with understanding electromagnetism. Electromagnetism can be called "electrodynamics" because it is a dynamic interaction between electrical and magnetic forces. Electromagnetism begins with the electr... | Introduction to quantum mechanics | Wikipedia | 475 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
The Standard Model of particle physics is the quantum field theory that describes three of the four known fundamental forces (electromagnetic, weak and strong interactions – excluding gravity) in the universe and classifies all known elementary particles. It was developed in stages throughout the latter half of the 20t... | Introduction to quantum mechanics | Wikipedia | 450 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Light behaves in some aspects like particles and in other aspects like waves. Matter—the "stuff" of the universe consisting of particles such as electrons and atoms—exhibits wavelike behavior too. Some light sources, such as neon lights, give off only certain specific frequencies of light, a small set of distinct pure ... | Introduction to quantum mechanics | Wikipedia | 497 | 2796131 | https://en.wikipedia.org/wiki/Introduction%20to%20quantum%20mechanics | Physical sciences | Quantum mechanics | Physics |
Rose is the color halfway between red and magenta on the HSV color wheel, also known as the RGB color wheel, on which it is at hue angle of 330 degrees.
Rose is one of the tertiary colors on the HSV (RGB) color wheel. The complementary color of rose is spring green. Sometimes rose is quoted instead as the web-safe col... | Rose (color) | Wikipedia | 400 | 2796768 | https://en.wikipedia.org/wiki/Rose%20%28color%29 | Physical sciences | Colors | Physics |
Occult
According to New Age author C. W. Leadbeater, who claimed to be clairvoyant, of the seven types of etheric atoms that he claimed to be able to observe with his third eye circulating through the human etheric body (colored violet, blue, green, yellow, orange, dark red, and rose), the flow of the rose colored eth... | Rose (color) | Wikipedia | 237 | 2796768 | https://en.wikipedia.org/wiki/Rose%20%28color%29 | Physical sciences | Colors | Physics |
In geography, a confluence (also: conflux) occurs where two or more watercourses join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); or where two streams meet to become the source of a river of a new name (such as the conflu... | Confluence | Wikipedia | 487 | 3755359 | https://en.wikipedia.org/wiki/Confluence | Physical sciences | Hydrology | Earth science |
In hydraulic civil engineering, where two or more underground culverted / artificially buried watercourses intersect, great attention should be paid to the hydrodynamic aspects of the system to ensure the longevity and efficiency of the structure.
Engineers have to design these systems whilst considering a list of fac... | Confluence | Wikipedia | 486 | 3755359 | https://en.wikipedia.org/wiki/Confluence | Physical sciences | Hydrology | Earth science |
Africa
At Lokoja, Nigeria, the Benue River flows into the Niger.
At Kazungula in Zambia, the Chobe River flows into the Zambezi. The confluence defines the tripoint of Zambia (north of the rivers), Botswana (south of the rivers) and Namibia (west of the rivers). The land border between Botswana and Zimbabwe to the ea... | Confluence | Wikipedia | 367 | 3755359 | https://en.wikipedia.org/wiki/Confluence | Physical sciences | Hydrology | Earth science |
Kuala Lumpur, the capital of Malaysia, is where the Gombak River (previously known as Sungai Lumpur, which means "muddy river") flows into the Klang River at the site of the Jamek Mosque. Recently, the Kolam Biru (Blue Pool), a pool with elaborate fountains, has been installed at the apex of the confluence.
Both Taipei... | Confluence | Wikipedia | 493 | 3755359 | https://en.wikipedia.org/wiki/Confluence | Physical sciences | Hydrology | Earth science |
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