507 research outputs found
Reconstruction of a vertex algebra in higher dimensions from its one-dimensional restriction
Vertex algebras in higher dimensions correspond to models of quantum field
theory with global conformal invariance. Any vertex algebra in higher
dimensions admits a restriction to a vertex algebra in any lower dimension, and
in particular, to dimension one. In this paper, we find natural conditions
under which the converse passage is possible. These conditions include a
unitary action of the conformal Lie algebra with a positive energy, which is
given by local endomorphisms and obeys certain integrability properties.Comment: 25 pages; v2 fixed typos and expanded some proofs; v3 improved the
expositio
Plasma levels of apolipoprotein-E in residents of the European North of Russia
Background: Apolipoprotein-E (apoE) is one of the metabolically active apoproteins and plays an important role in
lipid metabolism. However, there are no data on levels of apoE in residents of the North in spite of the fact that
specific features of lipid metabolism in the northerners are described. The present work was designed to study
plasma levels of apoE in residents of the European North of Russia.
Methods: A total of 937 native residents of the European North of Russia (463 men and 474 women) aged 13–60 years
were included in the study. ApoE concentrations in the blood plasma were measured by immunoturbidimetric
method.
Results: Plasma levels of apoE in residents of the European North of Russia were low. ApoE concentrations below
the defined normal values were detected in 57.0% of the men and in 59.2% of the women. The mean plasma
levels of apoE did not significantly differ in men and women (2.80 mg/dl vs 2.87 mg/dl). Plasma apoE
concentrations in residents of the European North of Russia changed with age. Plasma levels of apoE decreased
from 13 to 21 years in men and from 13 to 35 years in women and then increased in both sexes (p < 0.001).
Conclusion: The limits of variation of plasma apoE levels in residents of the European North of Russia shift
towards lower values. Plasma levels of apoE below normal values were observed in approximately half of
investigation subjects
Infinite dimensional Lie algebras in 4D conformal quantum field theory
The concept of global conformal invariance (GCI) opens the way of applying
algebraic techniques, developed in the context of 2-dimensional chiral
conformal field theory, to a higher (even) dimensional space-time. In
particular, a system of GCI scalar fields of conformal dimension two gives rise
to a Lie algebra of harmonic bilocal fields, V_m(x,y), where the m span a
finite dimensional real matrix algebra M closed under transposition. The
associative algebra M is irreducible iff its commutant M' coincides with one of
the three real division rings. The Lie algebra of (the modes of) the bilocal
fields is in each case an infinite dimensional Lie algebra: a central extension
of sp(infty,R) corresponding to the field R of reals, of u(infty,infty)
associated to the field C of complex numbers, and of so*(4 infty) related to
the algebra H of quaternions. They give rise to quantum field theory models
with superselection sectors governed by the (global) gauge groups O(N), U(N),
and U(N,H)=Sp(2N), respectively.Comment: 16 pages, with minor improvements as to appear in J. Phys.
The Secondary Electron Yield of Technical Materials and its Variation with Surface Treatments
Secondary electron emission of surfaces exposed to oscillating electromagnetic field is at the origin of the multipacting effect that could severely perturb the operation of particle accelerators. This contribution tries to illustrate by measurement results, the origin of the secondary electron emission as well as the main reasons for the discrepancies between technical materials and pure metals. The variation of the secondary electron yield with the incident electron energy will be discussed for various types of technical surfaces. The influence of a gas condensation on these surfaces will also be addressed in the context of the LHC accelerator. Various treatments aiming at a permanent reduction of the secondary electron yield will be presented. A special attention will be paid to the decrease of the secondary electron yield under electron or photon impact and to its possible beneficial consequences for the processing of devices prone to multipacting
Nudiviruses in free-living and parasitic arthropods: evolutionary taxonomy
The nudiviruses (family: Nudiviridae) are large double-stranded DNA (dsDNA)viruses that infect insects and crustaceans, and have most recently been identifiedfrom ectoparasitic members (fleas and lice). This virus family was created in 2014and has since been expanded via the discovery of multiple novel viral candidatesor accepted members, sparking the need for a new taxonomic and evolutionaryoverview. Using current information (including data from public databases), we construct a new comprehensive phylogeny, encompassing 49 different nudiviruses. Weuse this novel phylogeny to propose a new taxonomic structure of the Nudiviridaeby suggesting two new viral genera (Zetanudivirus and Etanudivirus), from ectoparasitic lice. We detail novel emerging relationships between nudiviruses and theirhosts, considering their evolutionary history and ecological role
Стійкість складних ландшафтних комплексів: формалізація моделі
The concept of "sustainability" for the composite landscape complex is defined in the paper. The logical sequence of the risk development process in a landscape complex is described. A system of criteria has been developed based on the subdivision of a large number of anthropogenic impacts on biota into four orderly groups. Anthropogenic impacts are categorised according to four levels of impaired biota. Most of the traditional toxic effects (increased mortality, disorders of ontogenesis and pathology of the organs, etc.) belong to the group corresponding to the level of individual and population responses (level 1). Another group of disorders and change parameters contains the following: change in primary productivity, change in aggregate indicators of biomass, change in the concentration of chlorophyll in the forest ecosystem, and other systemic disorders associated with accumulation of heavy metals and radionuclides (level 2). Very important yet under-described violations relate to the level of sustainability and integrity of ecosystems (level 3). The group of violations of the contribution of ecosystems to biosphere processes (level 4) including biogeochemical flows of elements completes this system. The approach presented is useful in the development of the most adequate system of criteria and priorities to assess and classify ecological risk of anthropogenic impacts including ecological danger of pollutants. In the proposed system of environmental hazard analysis, due place occupies a risk of affecting the stability and integrity of ecosystems, an example of which can serve as a risk of weakening of relationships between biotic components of a composite landscape complex and abiotic environmental factors. If an anthropogenic effect weakens this relationship in the ecosystem, the consequences can be unfavourable. Thus, the description of the CLC components should contain input variables and parameters characterizing the activity of the pollutant in each component and the density of contamination of individual components. The description of forest ecosystems considers the concept of runeblades approach to the analysis of ecological hazards of anthropogenic disturbances on biota. The system of criteria simplifies and streamlines the analysis of the ecological role and consequences of violations of specific physiological functions. Turning to the proposed system from level to level, it is convenient to trace the scale of the environmental effects of violations on an individual level, but is able to express themselves in an ecologically hazardous form at other levels of organization of landscapes complex.Визначено поняття "стійкості" для складного ландшафтного комплексу. Описано логічною послідовністю процес розвитку небезпеки у складному ландшафтному комплексі. Розроблено систему критеріїв, в основі якої, є зведення в чотири впорядкованих групи великої кількості антропогенних впливів на біоту. Антропогенні впливи поділяють відповідно з чотирма рівнями порушень біоти. Більшість традиційних токсичних ефектів (збільшення смертності, порушення онтогенезу та патології органів і т.ін.) потрапляє в групу, відповідну до рівня індивідуальних і популяційних відгуків (рівень 1). Ще одна група порушень та змін таких параметрів, як зміна первинної продуктивності; зміна агрегованих показників біомаси; зміна концентрації хлорофілу у лісовій екосистемі, інші системні порушення пов'язані з накопиченням важких металів та радіонуклідів (рівень 2). Дуже важливі і поки недостатньо охарактеризовані порушення відносяться до рівня стійкості та цілісності екосистем (рівень 3). Завершує цю систему група порушень вкладу екосистем в біосферні процеси (рівень 4), зокрема і в біогеохімічні потоки елементів. Розроблений підхід корисний під час розроблення максимально адекватної системи критеріїв і пріоритетів для оцінки і класифікації екологічної небезпеки антропогенних впливів зокрема екологічної небезпеки забруднювальних речовин. У запропонованій системі аналізу екологічної небезпеки належне місце займає небезпека впливу на стійкість і цілісність екосистеми, прикладом якої може слугувати небезпека ослаблення зв'язку між біотичними компонентами складного ландшафтного комплексу та абіотичними чинниками навколишнього середовища. Наведено опис лісової екосистеми враховуючи концепцію рівнеблокового підходу до аналізу екологічних небезпек антропогенного порушення біоти
Четверта міжнародна наукова-практична конференція «Комп’ютерне моделювання в хімії і технологіях та системах сталого розвитку»
Проаналізовано систему планування навчального процесу в частині дисциплін
професійної та практичної підготовки бакалаврів за напрямом Автоматизація та
комп’ютерно-інтегровані технології. Як розширення структурно-логічної схеми,
запропоновано ланцюгову схему планування таких дисциплін.The system of the educational process’ planning in the professional and practical training
disciplines for Bachelors of Automation and Computer Integrated Technologies is analised. The
chain scheme planning such disciplines as aecursive structural and logical scheme is proposed.Проанализирована система планирования учебного процесса в части дисциплин
профессиональной и практической подготовки бакалавров по направлению Автоматизация и компьютерно-интегрированные технологии. Как расширение структурно-логической
схемы, предложено цепную схему планирования таких дисциплин
Jacobi Identity for Vertex Algebras in Higher Dimensions
Vertex algebras in higher dimensions provide an algebraic framework for
investigating axiomatic quantum field theory with global conformal invariance.
We develop further the theory of such vertex algebras by introducing formal
calculus techniques and investigating the notion of polylocal fields. We derive
a Jacobi identity which together with the vacuum axiom can be taken as an
equivalent definition of vertex algebra.Comment: 35 pages, references adde
Unitary Positive-Energy Representations of Scalar Bilocal Quantum Fields
The superselection sectors of two classes of scalar bilocal quantum fields in
D>=4 dimensions are explicitly determined by working out the constraints
imposed by unitarity. The resulting classification in terms of the dual of the
respective gauge groups U(N) and O(N) confirms the expectations based on
general results obtained in the framework of local nets in algebraic quantum
field theory, but the approach using standard Lie algebra methods rather than
abstract duality theory is complementary. The result indicates that one does
not lose interesting models if one postulates the absence of scalar fields of
dimension D-2 in models with global conformal invariance. Another remarkable
outcome is the observation that, with an appropriate choice of the Hamiltonian,
a Lie algebra embedded into the associative algebra of observables completely
fixes the representation theory.Comment: 27 pages, v3: result improved by eliminating redundant assumptio
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