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{| class="wikitable" style="text-align:center;" width=150
! colspan=4 | Inputs !! colspan=2 | Outputs
|-
! S !! R !! D !! > !! Q !!
|-
| 0 || 1 || || || 0 || 1
|-
| 1 || 0 || || || 1 || 0
|-
| 1 || 1 || || || 1 || 1
|}
These flip-flops are very useful, as they form the basis for shift registers, which are an es... | Flip-flop (electronics) | Wikipedia | 489 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
The circuit is closely related to the gated D latch as both the circuits convert the two D input states (0 and 1) to two input combinations (01 and 10) for the output latch by inverting the data input signal (both the circuits split the single D signal in two complementary and signals). The difference is that NAND l... | Flip-flop (electronics) | Wikipedia | 500 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
Removing the leftmost inverter in the circuit creates a D-type flip-flop that strobes on the falling edge of a clock signal. This has a truth table like this:
{|class="wikitable" style="text-align:center;"
|-
! D !! Q !! > !! Qnext
|-
| 0 || || Falling || 0
|-
| 1 || || Falling || 1
|}
Dual-edge-triggered D flip-f... | Flip-flop (electronics) | Wikipedia | 512 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
(expanding the XOR operator)
and can be described in a truth table:
{| class="wikitable" style="text-align:center;"
|+ T flip-flop operation
|-
! colspan="4" | Characteristic table
! colspan="5" | Excitation table
|-
! !! !! !! Comment
! !! !! !! Comment
|-
| 0 || 0 || 0 || Hold state (no clock)
| 0 || 0 || 0 |... | Flip-flop (electronics) | Wikipedia | 310 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
The JK flip-flop, augments the behavior of the SR flip-flop (J: Set, K: Reset) by interpreting the J = K = 1 condition as a "flip" or toggle command. Specifically, the combination J = 1, K = 0 is a command to set the flip-flop; the combination J = 0, K = 1 is a command to reset the flip-flop; and the combination J = K ... | Flip-flop (electronics) | Wikipedia | 436 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
The input must be held steady in a period around the rising edge of the clock known as the aperture. Imagine taking a picture of a frog on a lily-pad. Suppose the frog then jumps into the water. If you take a picture of the frog as it jumps into the water, you will get a blurry picture of the frog jumping into the wate... | Flip-flop (electronics) | Wikipedia | 486 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
Set and Reset (and other) signals may be either synchronous or asynchronous and therefore may be characterized with either Setup/Hold or Recovery/Removal times, and synchronicity is very dependent on the design of the flip-flop.
Differentiation between Setup/Hold and Recovery/Removal times is often necessary when ver... | Flip-flop (electronics) | Wikipedia | 420 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
Unfortunately, it is not always possible to meet the setup and hold criteria, because the flip-flop may be connected to a real-time signal that could change at any time, outside the control of the designer. In this case, the best the designer can do is to reduce the probability of error to a certain level, depending on... | Flip-flop (electronics) | Wikipedia | 505 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
When cascading flip-flops which share the same clock (as in a shift register), it is important to ensure that the tCO of a preceding flip-flop is longer than the hold time (th) of the following flip-flop, so data present at the input of the succeeding flip-flop is properly "shifted in" following the active edge of the ... | Flip-flop (electronics) | Wikipedia | 388 | 32186638 | https://en.wikipedia.org/wiki/Flip-flop%20%28electronics%29 | Technology | Digital logic | null |
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written with a lower case d. It later came to be used in a cultural context to refe... | Deafness | Wikipedia | 275 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
Deafness can be broken down into four different types of hearing loss: conductive hearing loss, sensorineural hearing loss, mixed hearing loss, and auditory neuropathy spectrum disorder. All of these forms of hearing loss cause an impairment in a person's hearing where they are not able to hear sounds correctly. These ... | Deafness | Wikipedia | 241 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
There are millions of people in the world who are living with deafness or hearing impairments. Survey of Income and Program Participation (SIPP) indicate that fewer than 1 in 20 Americans are currently deaf or hard of hearing. There are a lot of solutions available for people with hearing impairments. Some examples of... | Deafness | Wikipedia | 467 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
In a cultural context, Deaf culture refers to a tight-knit cultural group of people whose primary language is signed, and who practice social and cultural norms which are distinct from those of the surrounding hearing community. This community does not automatically include all those who are clinically or legally deaf,... | Deafness | Wikipedia | 462 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
The first known record of sign language in history comes from Plato's Cratylus, written in the fifth century BCE. In a dialogue on the "correctness of names", Socrates says, "Suppose that we had no voice or tongue, and wanted to communicate with one another, should we not, like the deaf and dumb, make signs with the ha... | Deafness | Wikipedia | 386 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
Schooling
Nicole M. Stephens and Jill Duncan say that parents often encounter difficulties when it comes time for them to choose an educational setting for their child. There are many things they consider when choosing that setting for them. Three things to consider would be the needs and abilities of the child, how t... | Deafness | Wikipedia | 182 | 42029762 | https://en.wikipedia.org/wiki/Deafness | Biology and health sciences | Disabilities | Health |
Time-domain astronomy is the study of how astronomical objects change with time. Said to have begun with Galileo's Letters on Sunspots, the field has now naturally expanded to encompass variable objects beyond the Solar System. Temporal variation may originate from movement of the source, or changes in the object itsel... | Time-domain astronomy | Wikipedia | 506 | 39304988 | https://en.wikipedia.org/wiki/Time-domain%20astronomy | Physical sciences | Astronomy basics | Astronomy |
The importance of time-domain astronomy was recognized in 2018 by German Astronomical Society by awarding a Karl Schwarzschild Medal to Andrzej Udalski for "pioneering contribution to the growth of a new field of astrophysics research, time-domain astronomy, which studies the variability of brightness and other paramet... | Time-domain astronomy | Wikipedia | 350 | 39304988 | https://en.wikipedia.org/wiki/Time-domain%20astronomy | Physical sciences | Astronomy basics | Astronomy |
The interest in transients has intensified when large CCD detectors started to be available to the astronomical community. As telescopes with larger fields of view and larger detectors come into use in the 1990s, first massive and regular survey observations were initiated - pioneered by the gravitational microlensing ... | Time-domain astronomy | Wikipedia | 332 | 39304988 | https://en.wikipedia.org/wiki/Time-domain%20astronomy | Physical sciences | Astronomy basics | Astronomy |
The effects of climate change on small island countries are affecting people in coastal areas through sea level rise, increasing heavy rain events, tropical cyclones and storm surges. These effects of climate change threaten the existence of many island countries, their peoples and cultures. They also alter ecosystems ... | Effects of climate change on small island countries | Wikipedia | 483 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
Patterns of increasing hazards, high levels of exposure, and acute vulnerability interact to result in high risk of small island developing states (SIDS) to climate change.
Small island developing states (SIDS) have long been recognized as being particularly at risk to climate change. These nations are often described... | Effects of climate change on small island countries | Wikipedia | 477 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
Economic impacts
SIDS may also have reduced financial and human capital to mitigate climate change risk, as many rely on international aid to cope with disasters like severe storms. Worldwide, climate change is projected to have an average annual loss of 0.5% GDP by 2030; in Pacific SIDS, it will be 0.75–6.5% GDP by 2... | Effects of climate change on small island countries | Wikipedia | 452 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
A study that engaged the experiences of residents in atoll communities found that the cultural identities of these populations are strongly tied to these lands. Human rights activists argue that the potential loss of entire atoll countries, and consequently the loss of national sovereignty, self-determination, cultures... | Effects of climate change on small island countries | Wikipedia | 433 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
The Maldives and Tuvalu particularly have played a prominent role on the international stage. In 2002, Tuvalu threatened to sue the United States and Australia in the International Court of Justice for their contribution to climate change and for not ratifying the Kyoto Protocol. The governments of both of these countr... | Effects of climate change on small island countries | Wikipedia | 500 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
The Human Rights Measurement Initiative finds that the climate crisis has worsened human rights conditions in the Solomon Islands greatly (5.0 out of 6). Human rights experts provided that the climate crisis has contributed to conflict in communities, negative future socio-economic outlook, and food instability.
Tuval... | Effects of climate change on small island countries | Wikipedia | 368 | 49557688 | https://en.wikipedia.org/wiki/Effects%20of%20climate%20change%20on%20small%20island%20countries | Physical sciences | Climate change | Earth science |
Livestock are the domesticated animals raised in an agricultural setting in order to provide labour and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals who are raised for consumption, and sometimes used to refer solely ... | Livestock | Wikipedia | 504 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Animal-rearing originated during the cultural transition to settled farming communities from hunter-gatherer lifestyles. Animals are domesticated when their breeding and living conditions are controlled by humans. Over time, the collective behaviour, lifecycle and physiology of livestock have changed radically. Many mo... | Livestock | Wikipedia | 412 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Animals can be kept extensively or intensively. Extensive systems involve animals roaming at will, or under the supervision of a herdsman, often for their protection from predators. Ranching in the Western United States involves large herds of cattle grazing widely over public and private lands. Similar cattle stations... | Livestock | Wikipedia | 489 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Good husbandry, proper feeding, and hygiene are the main contributors to animal health on farms, bringing economic benefits through maximised production. When, despite these precautions, animals still become sick, they are treated with veterinary medicines, by the farmer and the veterinarian. In the European Union, whe... | Livestock | Wikipedia | 476 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
In non-Western countries, providing access to markets has encouraged farmers to invest in livestock, with the result being improved livelihoods. For example, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has worked in Zimbabwe to help farmers make their most of their livestock herds.
I... | Livestock | Wikipedia | 443 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Although livestock production serves as a source of income, it can provide additional economic values for rural families, often serving as a major contributor to food security and economic security. Livestock can serve as insurance against risk and is an economic buffer (of income and food supply) in some regions and s... | Livestock | Wikipedia | 370 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Animal husbandry has a significant impact on the world environment. It is responsible for somewhere between 20 and 33% of the fresh water usage in the world, and livestock, and the production of feed for them, occupy about a third of Earth's ice-free land. Livestock production is a contributing factor in species extinc... | Livestock | Wikipedia | 495 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
Believing that livestock farming is cruel was cited as a reason for becoming vegan or vegetarian throughout the 2010s. | Livestock | Wikipedia | 21 | 25160767 | https://en.wikipedia.org/wiki/Livestock | Technology | Animal husbandry | null |
In biology, kleptothermy is any form of thermoregulation by which an animal shares in the metabolic thermogenesis of another animal. It may or may not be reciprocal, and occurs in both endotherms and ectotherms. One of its forms is huddling. However, kleptothermy can happen between different species that share the same... | Kleptothermy | Wikipedia | 423 | 25164088 | https://en.wikipedia.org/wiki/Kleptothermy | Biology and health sciences | Basics | Biology |
In white-backed mousebirds (Colius colius), individuals maintain rest-phase body temperature above 32 °C despite air temperatures as low as -3.4 °C. This rest-phase body temperature was synchronized among individuals that cluster. Sometimes, kleptothermy is not reciprocal and might be accurately described as heat-steal... | Kleptothermy | Wikipedia | 477 | 25164088 | https://en.wikipedia.org/wiki/Kleptothermy | Biology and health sciences | Basics | Biology |
Another example would be the case of the fairy prion (Pachyptila turtur) that forms a close association with a medium-sized reptile, the tuatara (Sphenodon punctatus). These reptiles share the burrows made by the birds, and often stay when the birds are present which helps maintain a higher body temperature. Research h... | Kleptothermy | Wikipedia | 488 | 25164088 | https://en.wikipedia.org/wiki/Kleptothermy | Biology and health sciences | Basics | Biology |
Evolution
Ectotherms and endotherms undergo different evolutionary perspectives where mammals and birds thermoregulate far more precisely than ectotherms. A major benefit of precise thermoregulation is the ability to enhance performance through thermal specialization. Therefore, mammals and birds are assumed to have e... | Kleptothermy | Wikipedia | 365 | 25164088 | https://en.wikipedia.org/wiki/Kleptothermy | Biology and health sciences | Basics | Biology |
White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. White blood cells are generally larger than red blood cells. They include three main subtypes: granulocyt... | White blood cell | Wikipedia | 452 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
The number of leukocytes in the blood is often an indicator of disease, and thus the white blood cell count is an important subset of the complete blood count. The normal white cell count is usually between 4 × 109/L and 1.1 × 1010/L. In the US, this is usually expressed as 4,000 to 11,000 white blood cells per microli... | White blood cell | Wikipedia | 345 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Overview
All white blood cells are nucleated, which distinguishes them from the anucleated red blood cells and platelets. Types of leukocytes can be classified in standard ways. Two pairs of broadest categories classify them either by structure (granulocytes or agranulocytes) or by cell lineage (myeloid cells or lympho... | White blood cell | Wikipedia | 319 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Neutrophils are the most abundant white blood cell, constituting 60–70% of the circulating leukocytes. They defend against bacterial or fungal infection. They are usually first responders to microbial infection; their activity and death in large numbers form pus. They are commonly referred to as polymorphonuclear (PMN)... | White blood cell | Wikipedia | 509 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Basophils are chiefly responsible for allergic and antigen response by releasing the chemical histamine causing the dilation of blood vessels. Because they are the rarest of the white blood cells (less than 0.5% of the total count) and share physicochemical properties with other blood cells, they are difficult to study... | White blood cell | Wikipedia | 247 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Lymphocytes are much more common in the lymphatic system than in blood. Lymphocytes are distinguished by having a deeply staining nucleus that may be eccentric in location, and a relatively small amount of cytoplasm. Lymphocytes include:
B cells make antibodies that can bind to pathogens, block pathogen invasion, acti... | White blood cell | Wikipedia | 397 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Monocytes, the largest type of white blood cell, share the "vacuum cleaner" (phagocytosis) function of neutrophils, but are much longer lived as they have an extra role: they present pieces of pathogens to T cells so that the pathogens may be recognized again and killed. This causes an antibody response to be mounted. ... | White blood cell | Wikipedia | 489 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
A range of disorders can cause decreases in white blood cells. This type of white blood cell decreased is usually the neutrophil. In this case the decrease may be called neutropenia or granulocytopenia. Less commonly, a decrease in lymphocytes (called lymphocytopenia or lymphopenia) may be seen.
Neutropenia
Neutropen... | White blood cell | Wikipedia | 368 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Defined as total lymphocyte count below 1.0x109/L, the cells most commonly affected are CD4+ T cells. Like neutropenia, lymphocytopenia may be acquired or intrinsic and there are many causes. This is not a complete list.
Inherited immune deficiency – severe combined immunodeficiency, common variable immunodeficiency, ... | White blood cell | Wikipedia | 504 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Neutrophilia is an increase in the absolute neutrophil count in the peripheral circulation. Normal blood values vary by age. Neutrophilia can be caused by a direct problem with blood cells (primary disease). It can also occur as a consequence of an underlying disease (secondary). Most cases of neutrophilia are secondar... | White blood cell | Wikipedia | 483 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
Differential leucocyte count: number/ (%) of different types of leucocytes per cubic mm. of blood. Below are reference ranges for various types leucocytes. | White blood cell | Wikipedia | 37 | 25164668 | https://en.wikipedia.org/wiki/White%20blood%20cell | Biology and health sciences | Circulatory system | null |
A seed plant or spermatophyte (; ), also known as a phanerogam (taxon Phanerogamae) or a phaenogam (taxon Phaenogamae), is any plant that produces seeds. It is a category of embryophyte (i.e. land plant) that includes most of the familiar land plants, including the flowering plants and the gymnosperms, but not ferns, m... | Seed plant | Wikipedia | 507 | 25164793 | https://en.wikipedia.org/wiki/Seed%20plant | Biology and health sciences | Seed plants (except flowering plants) | Plants |
A whole genome duplication event in the ancestor of seed plants occurred about . This gave rise to a series of evolutionary changes that resulted in the origin of modern seed plants.
A middle Devonian (385-million-year-old) precursor to seed plants from Belgium has been identified predating the earliest seed plants by... | Seed plant | Wikipedia | 467 | 25164793 | https://en.wikipedia.org/wiki/Seed%20plant | Biology and health sciences | Seed plants (except flowering plants) | Plants |
Other classifications group all the seed plants in a single division, with classes for the five groups:
Division Spermatophyta
Cycadopsida, the cycads
Ginkgoopsida, the ginkgo
Pinopsida, the conifers, ("Coniferopsida")
Gnetopsida, the gnetophytes
Magnoliopsida, the flowering plants, or Angiospermopsida
A more mo... | Seed plant | Wikipedia | 403 | 25164793 | https://en.wikipedia.org/wiki/Seed%20plant | Biology and health sciences | Seed plants (except flowering plants) | Plants |
The danionins are a group of small, minnow-type fish belonging to the family Cyprinidae. Species of this group are in the genera clades Danio and Devario (which also includes Chela, Laubuka, Microdevario, and Microrasbora genera), based on the latest phylo-genetic research by Fang et al in 2009. They are primarily nati... | Danionin | Wikipedia | 505 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
These fish are easily stressed by flowing water and bright light. They occur in stagnant water with pH values between 3 and 5 caused by peat, which accumulates from a dense canopy. Generally, this also results in them being subtropical with temperatures of often being fine; they are good jumpers, so a tight-fitting l... | Danionin | Wikipedia | 400 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
The danionin group was thought to include Parabarilius, Danio, Brachydanio, and Danionella. In this scheme, danionins were distinguished from other cyprinids by the uniquely shared character of the "danionin notch", a large and peculiarly shaped indentation in the medial margin of the mandibles; this feature is not not... | Danionin | Wikipedia | 472 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
In another paper, Celestichthys margaritatus was described as a new species of the Danioninae. Apparently, it is most closely related to Microrasbora erythromicron; the other Microrasbora species differ significantly from Celestichthys. The genus is identified as a danionin due specializations of its lower jaw and its ... | Danionin | Wikipedia | 389 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
Also in 2007, another study analyzed the relationships of Danio. These authors considered Rasborinae to have priority over Danioninae, suggesting that they have the same meaning. Also, Danio was found to be the sister group of a clade including Chela, Microrasbora, Devario, and Inlecypris, rather than in a clade exclus... | Danionin | Wikipedia | 146 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
In 2009 and 2010, detailed mitochondrial and nuclear DNA analyses of the phylogenetic interrelationships of the danionins were published by Fang et al (Zoologica Scripta, 38, 3, 2009) and Tang et al (Molecular Phylogenetics and Evolution 57, 2010). These two significant studies confirmed or established several taxonomi... | Danionin | Wikipedia | 463 | 33816021 | https://en.wikipedia.org/wiki/Danionin | Biology and health sciences | Cypriniformes | Animals |
In logic, a quantifier is an operator that specifies how many individuals in the domain of discourse satisfy an open formula. For instance, the universal quantifier in the first order formula expresses that everything in the domain satisfies the property denoted by . On the other hand, the existential quantifier in ... | Quantifier (logic) | Wikipedia | 445 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
Consider the following statement (using dot notation for multiplication):
1 · 2 = 1 + 1, and 2 · 2 = 2 + 2, and 3 · 2 = 3 + 3, ..., and 100 · 2 = 100 + 100, and ..., etc.
This has the appearance of an infinite conjunction of propositions. From the point of view of formal languages, this is immediately a problem, since... | Quantifier (logic) | Wikipedia | 509 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
An example of translating a quantified statement in a natural language such as English would be as follows. Given the statement, "Each of Peter's friends either likes to dance or likes to go to the beach (or both)", key aspects can be identified and rewritten using symbols including quantifiers. So, let X be the set of... | Quantifier (logic) | Wikipedia | 468 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
Mathematical formulas mix symbolic expressions for quantifiers with natural language quantifiers such as,
For every natural number x, ...
There exists an x such that ...
For at least one x, ....
Keywords for uniqueness quantification include:
For exactly one natural number x, ...
There is one and only one x such ... | Quantifier (logic) | Wikipedia | 499 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
The maximum depth of nesting of quantifiers in a formula is called its "quantifier rank".
Equivalent expressions
If D is a domain of x and P(x) is a predicate dependent on object variable x, then the universal proposition can be expressed as
This notation is known as restricted or relativized or bounded quantificatio... | Quantifier (logic) | Wikipedia | 466 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
In some mathematical theories, a single domain of discourse fixed in advance is assumed. For example, in Zermelo–Fraenkel set theory, variables range over all sets. In this case, guarded quantifiers can be used to mimic a smaller range of quantification. Thus in the example above, to express
For every natural number n... | Quantifier (logic) | Wikipedia | 503 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
is the function H of n-1 arguments such that H(v1, ..., vn-1) = T if and only if F(v1, ..., vn-1, w) = T for at least one w and H(v1, ..., vn-1) = F otherwise.
The semantics for uniqueness quantification requires first-order predicate calculus with equality. This means there is given a distinguished two-placed predic... | Quantifier (logic) | Wikipedia | 494 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
Other quantifiers
A few other quantifiers have been proposed over time. In particular, the solution quantifier, noted § (section sign) and read "those". For example,
is read "those n in N such that n2 ≤ 4 are in {0,1,2}." The same construct is expressible in set-builder notation as
Contrary to the other quantifiers, ... | Quantifier (logic) | Wikipedia | 503 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
In work that culminated in Peirce (1885), Charles Sanders Peirce and his student Oscar Howard Mitchell independently invented universal and existential quantifiers, and bound variables. Peirce and Mitchell wrote Πx and Σx where we now write ∀x and ∃x. Peirce's notation can be found in the writings of Ernst Schröder, Le... | Quantifier (logic) | Wikipedia | 424 | 43507260 | https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | Mathematics | Mathematical logic | null |
Heavy metals is a controversial and ambiguous term for metallic elements with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context and has been argued should not be used. A heavy metal may be defined on the basis o... | Heavy metals | Wikipedia | 457 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Heavy metals are relatively rare in the Earth's crust but are present in many aspects of modern life. They are used in, for example, golf clubs, cars, antiseptics, self-cleaning ovens, plastics, solar panels, mobile phones, and particle accelerators.
Definitions
Controversial terminology
The International Union of P... | Heavy metals | Wikipedia | 460 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
The United States Pharmacopeia includes a test for heavy metals that involves precipitating metallic impurities as their coloured sulfides. On the basis of this type of chemical test, the group would include the transition metals and post-transition metals.
A different chemistry-based approach advocates replacing the... | Heavy metals | Wikipedia | 468 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Trace amounts of some heavy metals, mostly in period 4, are required for certain biological processes. These are iron and copper (oxygen and electron transport); cobalt (complex syntheses and cell metabolism); vanadium and manganese (enzyme regulation or functioning); chromium (glucose utilisation); nickel (cell growth... | Heavy metals | Wikipedia | 443 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Environmental heavy metals
Chromium, arsenic, cadmium, mercury, and lead have the greatest potential to cause harm on account of their extensive use, the toxicity of some of their combined or elemental forms, and their widespread distribution in the environment. Hexavalent chromium, for example, is highly toxic as are ... | Heavy metals | Wikipedia | 424 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Other heavy metals
A few other non-essential heavy metals have one or more toxic forms. Kidney failure and fatalities have been recorded arising from the ingestion of germanium dietary supplements (~15 to 300 g in total consumed over a period of two months to three years). Exposure to osmium tetroxide (OsO4) may cause ... | Heavy metals | Wikipedia | 404 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Heavier heavy metals are not usually formed this way since fusion reactions involving such nuclei would consume rather than release energy. Rather, they are largely synthesised (from elements with a lower atomic number) by neutron capture, with the two main modes of this repetitive capture being the s-process and the r... | Heavy metals | Wikipedia | 458 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Heavy metals are found primarily as lithophiles (rock-loving) or chalcophiles (ore-loving). Lithophile heavy metals are mainly f-block elements and the more reactive of the d-block elements. They have a strong affinity for oxygen and mostly exist as relatively low density silicate minerals. Chalcophile heavy metals are... | Heavy metals | Wikipedia | 436 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Broadly speaking, and with some exceptions, lithophile heavy metals can be extracted from their ores by electrical or chemical treatments, while chalcophile heavy metals are obtained by roasting their sulphide ores to yield the corresponding oxides, and then heating these to obtain the raw metals. Radium occurs in quan... | Heavy metals | Wikipedia | 317 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Some common uses of heavy metals depend on the general characteristics of metals such as electrical conductivity and reflectivity or the general characteristics of heavy metals such as density, strength, and durability. Other uses depend on the characteristics of the specific element, such as their biological role as n... | Heavy metals | Wikipedia | 466 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Heavy metals are used for ballast in boats, aeroplanes, and motor vehicles; or in balance weights on wheels and crankshafts, gyroscopes, and propellers, and centrifugal clutches, in situations requiring maximum weight in minimum space (for example in watch movements).
In military ordnance, tungsten or uranium is used ... | Heavy metals | Wikipedia | 401 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Selected heavy metals are used as catalysts in fuel processing (rhenium, for example), synthetic rubber and fibre production (bismuth), emission control devices (palladium and platinum), and in self-cleaning ovens (where cerium(IV) oxide in the walls of such ovens helps oxidise carbon-based cooking residues). In soap c... | Heavy metals | Wikipedia | 496 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Heavy metals are used in lighting, lasers, and light-emitting diodes (LEDs). Fluorescent lighting relies on mercury vapour for its operation. Ruby lasers generate deep red beams by exciting chromium atoms in aluminum oxide; the lanthanides are also extensively employed in lasers. Copper, iridium, and platinum are used ... | Heavy metals | Wikipedia | 295 | 46659847 | https://en.wikipedia.org/wiki/Heavy%20metals | Physical sciences | Periodic table | Chemistry |
Internal pressure is a measure of how the internal energy of a system changes when it expands or contracts at constant temperature. It has the same dimensions as pressure, the SI unit of which is the pascal.
Internal pressure is usually given the symbol . It is defined as a partial derivative of internal energy with ... | Internal pressure | Wikipedia | 484 | 26594247 | https://en.wikipedia.org/wiki/Internal%20pressure | Physical sciences | Thermodynamics | Physics |
Since the parameter is always positive, so is its internal pressure: internal energy of a van der Waals gas always increases when it expands isothermally.
The parameter models the effect of attractive forces between molecules in the gas. However, real non-ideal gases may be expected to exhibit a sign change between ... | Internal pressure | Wikipedia | 395 | 26594247 | https://en.wikipedia.org/wiki/Internal%20pressure | Physical sciences | Thermodynamics | Physics |
In astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life is most likely to develop. The concept of a galactic habitable zone analyzes various factors, such as metallicity (the presence of elements heavier than hydrogen and helium) and the rate and density of major ... | Galactic habitable zone | Wikipedia | 436 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
Modern galactic habitable-zone theory was introduced in 1986 by L.S. Marochnik and L.M. Mukhin of the Russian Space Research Institute, who defined the zone as the region in which intelligent life could flourish. Donald Brownlee and palaeontologist Peter Ward expanded upon the concept of a galactic habitable zone, as w... | Galactic habitable zone | Wikipedia | 450 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
The most common benchmark elemental ratio is that of Fe/H, one of the factors determining the propensity of a region of the galaxy to produce terrestrial planets. The galactic bulge, the region of the galaxy closest to the Galactic Center, has an [Fe/H] distribution peaking at −0.2 decimal exponent units (dex) relative... | Galactic habitable zone | Wikipedia | 498 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
While high metallicity is beneficial for the creation of terrestrial extrasolar planets, an excess amount can be harmful for life. Excess metallicity may lead to the formation of a large number of gas giants in a given system, which may subsequently migrate from beyond the system's frost line and become hot Jupiters, d... | Galactic habitable zone | Wikipedia | 380 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
Galactic morphology
Various morphological features of galaxies can affect their potential for habitability. Spiral arms, for example, are the location of star formation, but they contain numerous giant molecular clouds and a high density of stars that can perturb a star's Oort cloud, sending avalanches of comets and as... | Galactic habitable zone | Wikipedia | 447 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
The Lineweaver team also analyzed the evolution of the galactic habitable zone with respect to time, finding, for example, that stars close to the galactic bulge had to form within a time window of about two billion years in order to have habitable planets. Before that window, galactic-bulge stars would be prevented fr... | Galactic habitable zone | Wikipedia | 483 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
Criticism
The idea of the galactic habitable zone has been criticized by Nikos Prantzos, on the grounds that the parameters to create it are impossible to define even approximately, and that thus the galactic habitable zone may merely be a useful conceptual tool to enable a better understanding of the distribution of l... | Galactic habitable zone | Wikipedia | 230 | 39308394 | https://en.wikipedia.org/wiki/Galactic%20habitable%20zone | Physical sciences | Planetary science | Astronomy |
Technological determinism is a reductionist theory in assuming that a society's technology progresses by following its own internal logic of efficiency, while determining the development of the social structure and cultural values. The term is believed to have originated from Thorstein Veblen (1857–1929), an American s... | Technological determinism | Wikipedia | 338 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
Influence of Karl Marx and Expansion by Clarence Ayres
Although Veblen is credited with coining the core ideas behind technological determinism, the influence of Karl Marx on these ideas is also significant. Marx argued that technology drives historical change by shaping the "material base" of society. For instance, h... | Technological determinism | Wikipedia | 319 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
Technological determinism has been summarized as 'The belief in technology as a key governing force in society ...' (Merritt Roe Smith). 'The idea that technological development determines social change ...' (Bruce Bimber). It changes the way people think and how they interact with others and can be described as '...a ... | Technological determinism | Wikipedia | 373 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
As technology changes, the ways in which it is utilized and incorporated into the daily lives of individuals within a culture consequently affect the ways of living, highlighting how technology ultimately determines societal growth through its influence on relations and ways of living within a culture. To illustrate, "... | Technological determinism | Wikipedia | 456 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
The other view follows what Smith and Marx (1998) dictate as "soft" determinism, where the development of technology is also dependent on social context, affecting how it is adopted into a culture, "and, if the technology is adopted, the social context will have important effects on how the technology is used and thus ... | Technological determinism | Wikipedia | 380 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
“Hard determinists” would view technology as developing independent from social concerns. They would say that technology creates a set of powerful forces acting to regulate our social activity and its meaning. According to this view of determinism we organize ourselves to meet the needs of technology, and the outcome o... | Technological determinism | Wikipedia | 504 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
Modern theorists of technology and society no longer consider technological determinism to be a very accurate view of the way in which we interact with technology, even though determinist assumptions and language fairly saturate the writings of many boosters of technology, the business pages of many popular magazines, ... | Technological determinism | Wikipedia | 420 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
In his influential but contested (see Woolgar and Cooper, 1999) article "Do Artifacts Have Politics?", Langdon Winner illustrates not a form of determinism but the various sources of the politics of technologies. Those politics can stem from the intentions of the designer and the culture of the society in which a techn... | Technological determinism | Wikipedia | 464 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
In opposition to technological determinism are those who subscribe to the belief of social determinism and postmodernism. Social determinists believe that social circumstances alone select which technologies are adopted, with the result that no technology can be considered "inevitable" solely on its own merits. Technol... | Technological determinism | Wikipedia | 331 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
Technological determinist Walter J. Ong reviews the societal transition from an oral culture to a written culture in his work Orality and Literacy: The Technologizing of the Word (1982). He asserts that this particular development is attributable to the use of new technologies of literacy (particularly print and writin... | Technological determinism | Wikipedia | 469 | 40626873 | https://en.wikipedia.org/wiki/Technological%20determinism | Technology | General | null |
A container is any receptacle or enclosure for holding a product used in storage, packaging, and transportation, including shipping.
Things kept inside of a container are protected on several sides by being inside of its structure. The term is most frequently applied to devices made from materials that are durable and ... | Container | Wikipedia | 509 | 42046835 | https://en.wikipedia.org/wiki/Container | Technology | Tools: General | null |
For transportation of goods on a larger scale, larger containers remained a problem, as customs officials inspecting imports had to deal with a lack of standardization in this field, and because predominantly wooden containers in use well into the twentieth century were prone to leaking or breaking. The standardized st... | Container | Wikipedia | 373 | 42046835 | https://en.wikipedia.org/wiki/Container | Technology | Tools: General | null |
A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual r... | Projector | Wikipedia | 437 | 28412183 | https://en.wikipedia.org/wiki/Projector | Technology | Optical instruments | null |
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