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sufficiency should be implemented as comprehensively as possible, to avoid savings in one sector being annihilated by the growing environmental footprint of another. Capping incomes and resource use are strategies that could mitigate rebound effects. == Research == === Ongoing projects === ENOUGH: the International Net...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
partners from the academic world, research, or civil society. It includes a strong consideration for energy sufficiency and lifestyle changes to reduce energy demand. EDITS Network – IIASA (2020–) The EDITS network (Energy Demand changes Induced by Technological and Social innovations) brings together experts of variou...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
as few resources as possible (focus on housing, mobility and land use). As part of the project, scientists from the University of Flensburg and employees of the City of Flensburg are conducting a real world laboratory on a sufficiency-oriented development of a 54-hectare redevelopment area. Consumer sufficiency as a pa...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
way that is lighter on resources. Sufficiency Policy in Rural Municipalities – Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) The research project analyzes how rural municipalities in Switzerland can adopt sufficiency policies and contribute to sustainable development. It examines the potential f...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
efficiency and consistency strategies. To this end, existing sufficiency approaches and concepts in the building sector will be researched and analyzed, e.g. the optimization of existing use or the adaptability of buildings to changing conditions of use and requirements over the life cycle, for which significant potent...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
sustainable energy practices initiatives into two energy modelling tools and developed modified Danish, Latvian and Lithuanian national sustainable energy scenarios building upon the combination of sufficiency, efficiency and renewable energy. EU policy guidance on energy sufficiency – eceee (2017–2020) This project ai...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
involved three French universities (Université de Rouen Normandie, Université de Rennes 1, Université Paris-Est Marne-la-Vallée). Digitalization and social-ecological transformation: rebound risks and potential for sufficiency of digital services – IÖW / TU Berlin (2016–2022) This project examined the social and enviro...	{ "page_id": 5121209, "title": "Eco-sufficiency" }
initiative in Heidelberg, the municipality in Dortmund and a housing industry company in Kelsterbach. The initiative for the conception, implementation and diffusion of sufficiency practices originated significantly from these lead actors and the implementation of their initiatives has already begun. == References ==	{ "page_id": 5121209, "title": "Eco-sufficiency" }
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with family as it is used in taxonomy. Proteins in a family descen...	{ "page_id": 468154, "title": "Protein family" }
it. == Protein domains and motifs == Protein families were first recognised when most proteins that were structurally understood were small, single-domain proteins such as myoglobin, hemoglobin, and cytochrome c. Since then, many proteins have been found with multiple independent structural and functional units called ...	{ "page_id": 468154, "title": "Protein family" }
of evolution, sometimes in concert with whole genome duplications. Expansions are less likely, and losses more likely, for intrinsically disordered proteins and for protein domains whose hydrophobic amino acids are further from the optimal degree of dispersion along the primary sequence. This expansion and contraction ...	{ "page_id": 468154, "title": "Protein family" }
=== == References == == External links == Media related to Protein families at Wikimedia Commons	{ "page_id": 468154, "title": "Protein family" }
There are two tin acetates: Tin(II) acetate, (CH3CO2)2Sn Tin(IV) acetate, (CH3CO2)4Sn	{ "page_id": 76620985, "title": "Tin acetate" }
Good Natured is a book by primatologist Frans de Waal on animal behavior and the evolution of ethics. == Publishing history == The book was published in 1996 by Harvard University Press under the full title Good Natured: The Origins of Right and Wrong in Humans and Other Animals. Much of the book details observations o...	{ "page_id": 9905340, "title": "Good Natured" }
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and the dorsal body cavity. In the dorsal body cavity the brain and spinal cord...	{ "page_id": 74941, "title": "Body cavity" }
cavity, enclosed by the ribcage and contains the lungs and heart; and the abdominopelvic cavity. The abdominopelvic cavity can be divided into the abdominal cavity, enclosed by the ribcage and pelvis and contains the kidneys, ureters, stomach, intestines, liver, gallbladder, and pancreas; and the pelvic cavity, enclose...	{ "page_id": 74941, "title": "Body cavity" }
and the spinal cavity encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a color...	{ "page_id": 74941, "title": "Body cavity" }
fails to close, ventral body wall defects can result, such as ectopia cordis, a congenital malformation in which the heart is abnormally located outside the thorax. Another defect is gastroschisis, a congenital defect in the anterior abdominal wall through which the abdominal contents freely protrude. Another possibili...	{ "page_id": 74941, "title": "Body cavity" }
tissues or disrupting the activity of nearby organs. The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The dorsal cavity includes the cranial and spinal cavities. == Other animals == Organisms can be also classified according to the type of body cavity they possess, such as ps...	{ "page_id": 74941, "title": "Body cavity" }
Whale feces, the excrement of whales, has a vital role in the ecology of oceans, earning whales the title of "marine ecosystem engineers." This significant ecological role stems from the nutrients and compounds found in whale feces, which have far-reaching effects on marine life. Nitrogen and iron chelate released by c...	{ "page_id": 43590845, "title": "Whale feces" }
the rivers combined, enriching both primary and secondary productivity. Additionally, the iron-rich feces of krill-eating whales encourage phytoplankton growth, benefiting the marine food chain and sequestering carbon dioxide for extended periods. The Southern Ocean, rich in nutrients but iron-deficient, experiences in...	{ "page_id": 43590845, "title": "Whale feces" }
other detritus from surface to bottom. The phenomenon has been termed the "whale pump". The Gulf of Maine study also found that the view of whales and other marine mammals as competitors for fishing, advocated by some nations, is incorrect as whales play a vital role in maintaining the productivity of phytoplankton and...	{ "page_id": 43590845, "title": "Whale feces" }
iron in the ocean, up to 24% of the iron held in the surface waters of Southern Ocean. Whales formed part of a positive feedback loop and if whale populations are allowed to recover in the Southern Ocean, greater productivity of phytoplankton will result as larger amounts of iron are recycled through the system. Accord...	{ "page_id": 43590845, "title": "Whale feces" }
earlier estimates based on surface prey remains. The study found that salmonids comprised over 98.6% of the identified genetic sequences with Chinook and Coho salmon species as the most important prey species. === As indicator for population decline === A research study, published in 2012, on impacts of overfishing and...	{ "page_id": 43590845, "title": "Whale feces" }
there was a shortage of prey and maximum during August at the height of availability of food. Similarly, thyroid hormones co-relate to nutritional stress, enabling animals to lower metabolism rates to better conserve declining nutrition. The Southern Resident Killer Whales arrive in the study area in spring after havin...	{ "page_id": 43590845, "title": "Whale feces" }
The obturator canal is a passageway formed in the obturator foramen by part of the obturator membrane and the pelvis. It connects the pelvis to the thigh. == Structure == The obturator canal is formed between the obturator membrane and the pelvis. The obturator artery, obturator vein, and obturator nerve all travel thr...	{ "page_id": 8332477, "title": "Obturator canal" }
The molecular formula C13H15N (molar mass: 185.27 g/mol) may refer to: Naphthylaminopropane 1-Naphthylaminopropane SU-11739	{ "page_id": 37627065, "title": "C13H15N" }
In quantum field theory, and in the significant subfields of quantum electrodynamics (QED) and quantum chromodynamics (QCD), the two-body Dirac equations (TBDE) of constraint dynamics provide a three-dimensional yet manifestly covariant reformulation of the Bethe–Salpeter equation for two spin-1/2 particles. Such a ref...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
the 4-potential A μ {\displaystyle A_{\mu }} . For QCD, each equation has the same structure as the ordinary one-body Dirac equation in the presence of an external field similar to the electromagnetic field and an additional external field given by in terms of a Lorentz invariant scalar S {\displaystyle S} . In natural...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
}(p_{2}-{\tilde {A}}_{2})^{\mu }+m_{2}c+{\tilde {S}}_{2}\right]\Psi &=0.\end{aligned}}} where c is the speed of light and p μ = − i ℏ ∂ ∂ x μ {\displaystyle p^{\mu }=-i\hbar {\frac {\partial }{\partial x_{\mu }}}} Natural units will be used below. A tilde symbol is used over the two sets of potentials to indicate that ...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
x_{\perp }} orthogonal to P {\displaystyle P} in which x ⊥ μ = ( η μ ν − P μ P ν / P 2 ) x ν , {\displaystyle x_{\perp }^{\mu }=(\eta ^{\mu \nu }-P^{\mu }P^{\nu }/P^{2})x_{\nu },\,} P μ x ⊥ μ = 0. {\displaystyle P_{\mu }x_{\perp }^{\mu }=0.\,} This implies that in the c.m. frame x ⊥ = ( 0 , x → = x → 1 − x → 2 ) {\disp...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
i {\displaystyle S_{i}} and A i μ {\displaystyle A_{i}^{\mu }} which appear in the ordinary one-body Dirac equation for scalar and vector potentials. These extra terms correspond to additional recoil spin-dependence not present in the one-body Dirac equation and vanish when one of the particles becomes very heavy (the ...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
. H = p x ˙ − L + λ i ϕ i , {\displaystyle {\mathcal {H}}=p{\dot {x}}-{\mathcal {L}}+\lambda _{i}\phi _{i},} This total Hamiltonian is traditionally called the Dirac Hamiltonian. Constraints arise naturally from parameter invariant actions of the form I = ∫ d τ L ( τ ) = ∫ d τ ′ d τ d τ ′ L ( τ ) = ∫ d τ ′ L ( τ ′ ) . ...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
(x,p)).} One then postulates that for two bodies the Dirac Hamiltonian is the sum of two such mass shell constraints, H i = p i 2 + m i 2 + Φ i ( x 1 , x 2 , p 1 , p 2 ) ≈ 0 , {\displaystyle {\mathcal {H}}_{i}=p_{i}^{2}+m_{i}^{2}+\Phi _{i}(x_{1},x_{2},p_{1},p_{2})\approx 0,\,} that is H = λ 1 [ p 1 2 + m 1 2 + Φ 1 ( x ...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
O_{1}}{\partial p_{2}^{\mu }}}{\frac {\partial O_{2}}{\partial x_{2\mu }}}.} To see the consequences of having each constraint be a constant of the motion, take, for example H ˙ 1 = { H 1 , H } = λ 1 { H 1 , H 1 } + { H 1 , λ 1 } H 2 + λ 2 { H 2 , H 1 } + { λ 2 , H 1 } H 2 . {\displaystyle {\dot {\mathcal {H}}}_{1}=\{{...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
{H}}\Psi =0.} The first set of equations for i = 1, 2 play the role for spinless particles that the two Dirac equations play for spin-one-half particles. The classical Poisson brackets are replaced by commutators { O 1 , O 2 } → 1 i [ O 1 , O 2 ] . {\displaystyle \{O_{1},O_{2}\}\rightarrow {\frac {1}{i}}[O_{1},O_{2}].\...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
p 2 2 − p 1 2 2 − P 2 {\displaystyle \varepsilon _{2}=-{\frac {p_{2}\cdot P}{\sqrt {-P^{2}}}}=-{\frac {P^{2}+p_{2}^{2}-p_{1}^{2}}{2{\sqrt {-P^{2}}}}}} are the projections of the momenta p 1 {\displaystyle p_{1}} and p 2 {\displaystyle p_{2}} along the direction of the total momentum P {\displaystyle P} . Subtracting th...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
w 2 + m 1 2 − m 2 2 2 w Ψ {\displaystyle \varepsilon _{1}\Psi ={\frac {w^{2}+m_{1}^{2}-m_{2}^{2}}{2w}}\Psi } ε 2 Ψ = w 2 + m 2 2 − m 1 2 2 w Ψ . {\displaystyle \varepsilon _{2}\Psi ={\frac {w^{2}+m_{2}^{2}-m_{1}^{2}}{2w}}\Psi .} The relative momentum then satisfies p Ψ = ε 2 p 1 − ε 1 p 2 w Ψ , {\displaystyle p\Psi ={\...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
constituent four-momentum are the relativistic analogues of the non-relativistic equations p → = m 2 p → 1 − m 1 p → 2 M , p → 1 = m 1 M P → + p → , p → 2 = m 2 M P → − p → . {\displaystyle {\begin{aligned}{\vec {p}}&={\frac {m_{2}{\vec {p}}_{1}-m_{1}{\vec {p}}_{2}}{M}},\\[1ex]{\vec {p}}_{1}&={\frac {m_{1}}{M}}{\vec {P...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
kinematics: b 2 ( w 2 , m 1 2 , m 2 2 ) = 1 4 w 2 { w 4 − 2 w 2 ( m 1 2 + m 2 2 ) + ( m 1 2 − m 2 2 ) 2 } . {\displaystyle b^{2}(w^{2},m_{1}^{2},m_{2}^{2})={\frac {1}{4w^{2}}}\left\{w^{4}-2w^{2}(m_{1}^{2}+m_{2}^{2})+(m_{1}^{2}-m_{2}^{2})^{2}\right\}\,.} With the above constraint Eqs.(7) on Ψ {\displaystyle \Psi } then ...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
== A plausible structure for the quasipotential Φ {\displaystyle \Phi } can be found by observing that the one-body Klein–Gordon equation ( p 2 + m 2 ) ψ = ( p → 2 − ε 2 + m 2 ) ψ = 0 {\displaystyle (p^{2}+m^{2})\psi =({\vec {p}}^{2}-\varepsilon ^{2}+m^{2})\psi =0} takes the form ( p → 2 − ε 2 + m 2 + 2 m S + S 2 + 2 ε...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
A} ). The two kinematical variables m w {\displaystyle m_{w}} and ε w {\displaystyle \varepsilon _{w}} are related to one another by the Einstein condition ε w 2 − m w 2 = b 2 ( w ) , {\displaystyle \varepsilon _{w}^{2}-m_{w}^{2}=b^{2}(w),} If one introduces the four-vectors, including a vector interaction A μ {\displa...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
P ^ + p ; p 2 = ε 2 P ^ − p . {\displaystyle p_{1}=\varepsilon _{1}{\hat {P}}+p;~~p_{2}=\varepsilon _{2}{\hat {P}}-p~.} Defining structures that display time-like vector and scalar interactions π 1 = p 1 − A 1 = [ P ^ ( ε 1 − A 1 ) + p ] , {\displaystyle \pi _{1}=p_{1}-A_{1}=[{\hat {P}}(\varepsilon _{1}-{\mathcal {A}}_...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
2 ε w A − A 2 , {\displaystyle \pi _{2}^{2}-p^{2}=-\left(\varepsilon _{2}-{\mathcal {A}}_{2}\right)^{2}=-\varepsilon _{2}^{2}+2\varepsilon _{w}A-A^{2},} M 1 2 = m 1 2 + 2 m w S + S 2 , {\displaystyle M_{1}{}^{2}=m_{1}^{2}+2m_{w}S+S^{2},} M 2 2 = m 2 2 + 2 m w S + S 2 . {\displaystyle M_{2}^{2}=m_{2}^{2}+2m_{w}S+S^{2}.}...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
incorporates each or any number of these intereractions in concert is the so-called hyperbolic form of the TBDE. For combined scalar and vector interactions those forms ultimately reduce to the ones given in the first set of equations of this article. Those equations are called the external field-like forms because the...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
{\displaystyle \Delta } . That matrix structure is determined by the type of vertex-vertex structure incorporated in the interaction. For the two types of invariant interactions Δ {\displaystyle \Delta } emphasized in this article they are Δ L ( x ⊥ ) = − 1 1 1 2 L ( x ⊥ ) 2 O 1 , scalar , {\displaystyle \Delta _{\math...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
β i = − γ i ⋅ P ^ , {\displaystyle \beta _{i}=-\gamma _{i}\cdot {\hat {P}},} γ i ⊥ μ = ( η μ ν + P ^ μ P ^ ν ) γ ν i , {\displaystyle \gamma _{i\perp }^{\mu }=(\eta ^{\mu \nu }+{\hat {P}}^{\mu }{\hat {P}}^{\nu })\gamma _{\nu i},} Σ i = γ 5 i β i γ ⊥ i , {\displaystyle \Sigma _{i}=\gamma _{5i}\beta _{i}\gamma _{\perp i}...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
, {\displaystyle M_{1}=m_{1}\cosh {\mathcal {L}}+m_{2}\sinh {\mathcal {L}},} M 2 = m 2 cosh ⁡ L + m 1 sinh ⁡ L , {\displaystyle M_{2}=m_{2}\cosh {\mathcal {L}}+m_{1}\sinh {\mathcal {L}},} E 1 = ε 1 cosh ⁡ G − ε 2 sinh ⁡ G , {\displaystyle E_{1}=\varepsilon _{1}\cosh {\mathcal {G}}-\varepsilon _{2}\sinh {\mathcal {G}},}...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
{\mathcal {L}}.} The parametrization for L {\displaystyle {\mathcal {L}}} and G {\displaystyle {\mathcal {G}}} takes advantage of the Todorov effective external potential forms (as seen in the above section on the two-body Klein Gordon equations) and at the same time displays the correct static limit form for the Pauli...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
can be incorporated into those potentials. To see how this comes about, consider by contrast how one computes scattering amplitudes without quantum field theory. With no quantum field theory one must come upon potentials by classical arguments or phenomenological considerations. Once one has the potential V {\displayst...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
a recipe for this extension when the particles are confined and cannot split into clusters of a smaller number of particles with no inter-cluster interactions Lusanna has developed an approach, one that does not involve generalized mass shell constraints with no such restrictions, which extends to N bodies with or with...	{ "page_id": 36054202, "title": "Two-body Dirac equations" }
The Theory of Island Biogeography is a 1967 book by the ecologist Robert MacArthur and the biologist Edward O. Wilson. It is widely regarded as a seminal work in island biogeography and ecology. The Princeton University Press reprinted the book in 2001 as a part of the "Princeton Landmarks in Biology" series. The book ...	{ "page_id": 17310914, "title": "The Theory of Island Biogeography" }
rate. They further hypothesize that an increase in island size will lower extinction curves while a decrease in distance between the island and the source region will raise immigration curves. Since the intersection of immigration and extinction rate curves determines the species number, the authors predict that larger...	{ "page_id": 17310914, "title": "The Theory of Island Biogeography" }
this study. In Chapter 7, the authors state that there are generally three consecutive phases to the evolution of populations after colonization. Initially, there is a trend for colonizers to evolve from r-strategists into K-strategists. The founder effect may also influence colonizing populations during this first pha...	{ "page_id": 17310914, "title": "The Theory of Island Biogeography" }
used as a basis in other ecological theories, notably the unified neutral theory of biodiversity, and has been foundational for the fields of landscape ecology, invasion biology, and conservation biology. === Criticism === Several studies have disputed the underlying assumptions in MacArthur and Wilson's theory of isla...	{ "page_id": 17310914, "title": "The Theory of Island Biogeography" }
Molecular cloning is a set of experimental methods in molecular biology that are used to assemble recombinant DNA molecules and to direct their replication within host organisms. The use of the word cloning refers to the fact that the method involves the replication of one molecule to produce a population of cells with...	{ "page_id": 30876867, "title": "Molecular cloning" }
could be inserted into a plasmid and that these foreign sequences would be carried into bacteria and digested as part of the plasmid. That is, these plasmids could serve as cloning vectors to carry genes. Virtually any DNA sequence can be cloned and amplified, but there are some factors that might limit the success of ...	{ "page_id": 30876867, "title": "Molecular cloning" }
if any segment of DNA from any organism is inserted into a DNA segment containing the molecular sequences required for DNA replication, and the resulting recombinant DNA is introduced into the organism from which the replication sequences were obtained, then the foreign DNA will be replicated along with the host cell's...	{ "page_id": 30876867, "title": "Molecular cloning" }
DNA sequence and/or test entire libraries simultaneously, as opposed to of individual sequences. These shifts introduce complexity that require design to move away from the flat nucleotide-based representation and towards a higher level of abstraction. Examples of such tools are GenoCAD, Teselagen [5] (free for academi...	{ "page_id": 30876867, "title": "Molecular cloning" }
or more unique restriction endonuclease recognition sites to serve as sites where foreign DNA may be introduced a selectable genetic marker gene that can be used to enable the survival of cells that have taken up vector sequences a tag gene that can be used to screen for cells containing the foreign DNA === Preparation...	{ "page_id": 30876867, "title": "Molecular cloning" }
(extraction with phenol), RNA (ribonuclease) and smaller molecules (precipitation and/or chromatography). Polymerase chain reaction (PCR) methods are often used for amplification of specific DNA or RNA (RT-PCR) sequences prior to molecular cloning. DNA for cloning experiments may also be obtained from RNA using reverse...	{ "page_id": 30876867, "title": "Molecular cloning" }
itself and higher-order combinations of vector and foreign DNA) are also usually present. This complex mixture is sorted out in subsequent steps of the cloning process, after the DNA mixture is introduced into cells. === Introduction of recombinant DNA into host organism === The DNA mixture, previously manipulated in v...	{ "page_id": 30876867, "title": "Molecular cloning" }
with this issue through a step of artificial genetic selection, in which cells that have not taken up DNA are selectively killed, and only those cells that can actively replicate DNA containing the selectable marker gene encoded by the vector are able to survive. When bacterial cells are used as host organisms, the sel...	{ "page_id": 30876867, "title": "Molecular cloning" }
DNA from an organism) or relatively simple (as when moving a previously cloned DNA fragment into a different plasmid), but it is almost always necessary to examine a number of different clones to be sure that the desired DNA construct is obtained. This may be accomplished through a very wide range of experimental metho...	{ "page_id": 30876867, "title": "Molecular cloning" }
clone of a gene can lead to the development of organisms that produce the protein product of the cloned genes, termed a recombinant protein. In practice, it is frequently more difficult to develop an organism that produces an active form of the recombinant protein in desirable quantities than it is to clone the gene. T...	{ "page_id": 30876867, "title": "Molecular cloning" }
categories. The first is alteration of germ cells, that is, sperm or eggs, which results in a permanent genetic change for the whole organism and subsequent generations. This "germ line gene therapy" is considered by many to be unethical in human beings. The second type of gene therapy, "somatic cell gene therapy", is ...	{ "page_id": 30876867, "title": "Molecular cloning" }
Aplasia ( ; from Greek a, "not", "no" + plasis, "formation") is a birth defect where an organ or tissue is wholly or largely absent. It is caused by a defect in a developmental process. Aplastic anemia is the failure of the body to produce blood cells. It may occur at any time, and has multiple causes. == Types == === ...	{ "page_id": 4334788, "title": "Aplasia" }
formation of the blood-testis barrier and aid in sperm generation. These cells respond to follicle-stimulating hormone, which is secreted by the hypothalamus and aids in spermatogenesis. Men often learn they have Sertoli cell-only syndrome between the ages of 20 and 40 when they are checked for infertility and found to...	{ "page_id": 4334788, "title": "Aplasia" }
head, the retinal blood vessels, ganglion cells of the retina, and optic nerve fibers in an otherwise normal eye. Clinically, the condition is characterized by a lack of light perception, an afferent pupillary defect, and a fundus appearance of an absent optic nerve head and retinal vessels, as well as other ocular and...	{ "page_id": 4334788, "title": "Aplasia" }
biological development disorders == References ==	{ "page_id": 4334788, "title": "Aplasia" }
An artificial neural network (ANN) combines biological principles with advanced statistics to solve problems in domains such as pattern recognition and game-play. ANNs adopt the basic model of neuron analogues connected to each other in a variety of ways. == Structure == === Neuron === A neuron with label j {\displayst...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
= ∑ i o i ( t ) w i j . {\displaystyle p_{j}(t)=\sum _{i}o_{i}(t)w_{ij}.} === Bias === A bias term can be added, changing the form to the following: p j ( t ) = ∑ i o i ( t ) w i j + w 0 j , {\displaystyle p_{j}(t)=\sum _{i}o_{i}(t)w_{ij}+w_{0j},} where w 0 j {\displaystyle w_{0j}} is a bias. == Neural networks as func...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
provides a smooth transition as input values change, i.e. a small change in input produces a small change in output. The following refers to a collection of functions g i {\displaystyle \textstyle g_{i}} as a vector g = ( g 1 , g 2 , … , g n ) {\displaystyle \textstyle g=(g_{1},g_{2},\ldots ,g_{n})} . This figure depic...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
of the figure, where f {\displaystyle \textstyle f} is shown as dependent upon itself. However, an implied temporal dependence is not shown. == Backpropagation == Backpropagation training algorithms fall into three categories: steepest descent (with variable learning rate and momentum, resilient backpropagation); quasi...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
w p {\displaystyle w_{p}} , giving a new function x ↦ f N ( w p , x ) {\displaystyle x\mapsto f_{N}(w_{p},x)} . The computation is the same in each step, hence only the case i = 1 {\displaystyle i=1} is described. w 1 {\displaystyle w_{1}} is calculated from ( x 1 , y 1 , w 0 ) {\displaystyle (x_{1},y_{1},w_{0})} by co...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
the ratio, the faster the neuron trains, but the lower the ratio, the more accurate the training. The sign of the gradient of a weight indicates whether the error varies directly with or inversely to the weight. Therefore, the weight must be updated in the opposite direction, "descending" the gradient. Learning is repe...	{ "page_id": 61547718, "title": "Mathematics of artificial neural networks" }
A quadratic Lie algebra is a Lie algebra together with a compatible symmetric bilinear form. Compatibility means that it is invariant under the adjoint representation. Examples of such are semisimple Lie algebras, such as su(n) and sl(n,R). == Definition == A quadratic Lie algebra is a Lie algebra (g,[.,.]) together wi...	{ "page_id": 26092740, "title": "Quadratic Lie algebra" }
↦ ( a d X : Y ↦ [ X , Y ] ) {\displaystyle \mathrm {ad} \colon {\mathfrak {g}}\to \mathrm {End} ({\mathfrak {g}}):X\mapsto (\mathrm {ad} _{X}\colon Y\mapsto [X,Y])} . Define now the Killing form k : g ⊗ g → R : X ⊗ Y ↦ − t r ( a d X ∘ a d Y ) {\displaystyle k\colon {\mathfrak {g}}\otimes {\mathfrak {g}}\to \mathbb {R} ...	{ "page_id": 26092740, "title": "Quadratic Lie algebra" }
In the history of physics, a line of force in Michael Faraday's extended sense is synonymous with James Clerk Maxwell's line of induction. According to J.J. Thomson, Faraday usually discusses lines of force as chains of polarized particles in a dielectric, yet sometimes Faraday discusses them as having an existence all...	{ "page_id": 3024068, "title": "Line of force" }
the continuous transmission of electric and magnetic forces, considered these to be states of stress and strain in a mechanical aether. This was part of the quite different network of beliefs and problems with which Maxwell was working. == Views of Faraday == At first Michael Faraday considered the physical reality of ...	{ "page_id": 3024068, "title": "Line of force" }
which I have begun to develop in this paper, except that in 1846 there was no data to calculate the velocity of propagation. == Tube of force == Maxwell changed Faraday's phrase lines of force to tubes of force, when expressing his fluidic assumptions involved in his mathematization of Faraday's theories. A tube of for...	{ "page_id": 3024068, "title": "Line of force" }
p. 447 Faraday, Michael, Experimental Researches, Series 19. == Notes ==	{ "page_id": 3024068, "title": "Line of force" }
The rp-process (rapid proton capture process) consists of consecutive proton captures onto seed nuclei to produce heavier elements. It is a nucleosynthesis process and, along with the s-process and the r-process, may be responsible for the generation of many of the heavy elements present in the universe. However, it is...	{ "page_id": 4859082, "title": "Rp-process" }
sites == Sites suggested for the rp-process are accreting binary systems where one star is a neutron star. In these systems the donor star is accreting material onto its compact partner star. The accreted material is usually rich in hydrogen and helium because of its origin from the surface layers of the donor star. Be...	{ "page_id": 4859082, "title": "Rp-process" }
Ethology is a branch of zoology that studies the behaviour of non-human animals. It has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology...	{ "page_id": 9425, "title": "Ethology" }
database of behaviour. === Growth of the field === Due to the work of Konrad Lorenz and Niko Tinbergen, ethology developed strongly in continental Europe during the years prior to World War II. After the war, Tinbergen moved to the University of Oxford, and ethology became stronger in the UK, with the additional influe...	{ "page_id": 9425, "title": "Ethology" }
factors, namely inborn instincts, learning, and environmental factors. The latter include abiotic and biotic factors. Abiotic factors such as temperature or light conditions have dramatic effects on animals, especially if they are ectothermic or nocturnal. Biotic factors include members of the same species (e.g. sexual...	{ "page_id": 9425, "title": "Ethology" }
stimuli. For example, prairie dogs (Cynomys ludovicianus) give alarm calls when predators approach, causing all individuals in the group to quickly scramble down burrows. When prairie dog towns are located near trails used by humans, giving alarm calls every time a person walks by is expensive in terms of time and ener...	{ "page_id": 9425, "title": "Ethology" }
with a non-imitator. Imitation has been observed in recent research on chimpanzees; not only did these chimps copy the actions of another individual, when given a choice, the chimps preferred to imitate the actions of the higher-ranking elder chimpanzee as opposed to the lower-ranking young chimpanzee. ===== Stimulus a...	{ "page_id": 9425, "title": "Ethology" }
hand, and cleaning it with the other. This behaviour was soon expressed by the individuals living in contact with her; when they gave birth, this behaviour was also expressed by their young—a form of social transmission. ==== Teaching ==== Teaching is a highly specialized aspect of learning in which the "teacher" (demo...	{ "page_id": 9425, "title": "Ethology" }
complex mating ritual, studied by Tinbergen, is regarded as a notable example. Often in social life, animals fight for the right to reproduce, as well as social supremacy. A common example of fighting for social and sexual supremacy is the so-called pecking order among poultry. Every time a group of poultry cohabitate ...	{ "page_id": 9425, "title": "Ethology" }
altruistic, as indicated by the table below. For example, revengeful behaviour was at one point claimed to have been observed exclusively in Homo sapiens. However, other species have been reported to be vengeful including chimpanzees, as well as anecdotal reports of vengeful camels. Altruistic behaviour has been explai...	{ "page_id": 9425, "title": "Ethology" }
of group living. However, in nature, most groups are stable at slightly larger than optimal sizes. Because it generally benefits an individual to join an optimally-sized group, despite slightly decreasing the advantage for all members, groups may continue to increase in size until it is more advantageous to remain alon...	{ "page_id": 9425, "title": "Ethology" }
Conspectus of History 1.7 (1981). == External links == Media related to Ethology at Wikimedia Commons	{ "page_id": 9425, "title": "Ethology" }
In cryptography, learning with errors (LWE) is a mathematical problem that is widely used to create secure encryption algorithms. It is based on the idea of representing secret information as a set of equations with errors. In other words, LWE is a way to hide the value of a secret by introducing noise to it. In more t...	{ "page_id": 23864530, "title": "Learning with errors" }
Gödel Prize for this work); it is a generalization of the parity learning problem. Regev showed that the LWE problem is as hard to solve as several worst-case lattice problems. Subsequently, the LWE problem has been used as a hardness assumption to create public-key cryptosystems, such as the ring learning with errors ...	{ "page_id": 23864530, "title": "Learning with errors" }
/ q + Z ∈ T {\displaystyle 1/q+\mathbb {Z} \in \mathbb {T} } ), and the final addition is in T {\displaystyle \mathbb {T} } . Output the pair ( a , t ) {\displaystyle (\mathbf {a} ,t)} . The learning with errors problem L W E q , ϕ {\displaystyle \mathrm {LWE} _{q,\phi }} is to find s ∈ Z q n {\displaystyle \mathbf {s}...	{ "page_id": 23864530, "title": "Learning with errors" }
some polynomial in n {\displaystyle n} . === Solving decision assuming search === Intuitively, if we have a procedure for the search problem, the decision version can be solved easily: just feed the input samples for the decision problem to the solver for the search problem. Denote the given samples by { ( a i , b i ) ...	{ "page_id": 23864530, "title": "Learning with errors" }
{a} _{i}+(r,0,\ldots ,0),\mathbf {b} _{i}+(rk)/q)\}} . Send the transformed samples to the decision solver. If the guess k {\displaystyle k} was correct, the transformation takes the distribution A s , χ {\displaystyle A_{\mathbf {s} ,\chi }} to itself, and otherwise, since q {\displaystyle q} is prime, it takes it to ...	{ "page_id": 23864530, "title": "Learning with errors" }
DLWE problems for arbitrary q {\displaystyle q} and χ {\displaystyle \chi } . Given samples { ( a i , b i ) } {\displaystyle \{(\mathbf {a} _{i},\mathbf {b} _{i})\}} from A s , χ {\displaystyle A_{\mathbf {s} ,\chi }} , it is easy to see that { ( a i , b i + ⟨ a i , t ⟩ ) / q } {\displaystyle \{(\mathbf {a} _{i},\mathb...	{ "page_id": 23864530, "title": "Learning with errors" }

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