309 research outputs found
Evaluation of the health status of the employees of the leading metallurgical enterprise
The purpose and objectives of the study: To assess the health status of the employees of the leading metallurgical enterprise
Recommended from our members
Experimental study of laboratory-heated CM2 chondrites Mighei and Murchison
We conducted experimental heating of two CM2 chondrites, Murchison and Mighei, to study changes in their oxygen isotopic compositions and mineralogy and explore possible genetic relationships between MCCs and normal CMs
How to find discrete contact symmetries
This paper describes a new algorithm for determining all discrete contact
symmetries of any differential equation whose Lie contact symmetries are known.
The method is constructive and is easy to use. It is based upon the observation
that the adjoint action of any contact symmetry is an automorphism of the Lie
algebra of generators of Lie contact symmetries. Consequently, all contact
symmetries satisfy various compatibility conditions. These conditions enable
the discrete symmetries to be found systematically, with little effort
Instantons and Yang-Mills Flows on Coset Spaces
We consider the Yang-Mills flow equations on a reductive coset space G/H and
the Yang-Mills equations on the manifold R x G/H. On nonsymmetric coset spaces
G/H one can introduce geometric fluxes identified with the torsion of the spin
connection. The condition of G-equivariance imposed on the gauge fields reduces
the Yang-Mills equations to phi^4-kink equations on R. Depending on the
boundary conditions and torsion, we obtain solutions to the Yang-Mills
equations describing instantons, chains of instanton-anti-instanton pairs or
modifications of gauge bundles. For Lorentzian signature on R x G/H, dyon-type
configurations are constructed as well. We also present explicit solutions to
the Yang-Mills flow equations and compare them with the Yang-Mills solutions on
R x G/H.Comment: 1+12 page
ЭТНИЧЕСКИЕ АСПЕКТЫ НАСЛЕДСТВЕННОГО РАКА МОЛОЧНОЙ ЖЕЛЕЗЫ В РЕГИОНЕ СИБИРИ
Background: Ethnic diversity of the population in the region of Siberia suggests the existence of different germline mutations in the BRCA1/2 genes associated with breast and ovarian cancer in different ethnic populations, but spectrum of these mutations has not been studied. Objective: Our aim was to evaluate the frequency of the most common mutations BRCA1 / 2 (BRCA1 5382insC, BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT) in women diagnosed with breast cancer among indigenous people and newcomers living in Siberia. Methods: We tested 1281 genomic DNA samples for the presence of BRCA1 5382insC mutation in patients diagnosed with breast cancer considering no family history. 72 patients having hereditary cancer signs were tested for the mutations BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT. Results: Out of 765 patients of Slavic ethnic group, 27 women (3.5%) were carriers of allele BRCA1 5382insC. The frequencies of mutations in patients with signs of hereditary cancer were: 8.3% in group of young patients (under 40 years), 20.0% in patients with bilateral cancer and 5.7% in patients with family history of breast or ovarian cancers. We tested 516 BC patients residing on the territory of the Buryat-Aginsky district, Republics of Tyva and Altai. Out of them, there were 197 patients among the indigenous population (buryats, tuvinians, altaians), and 319 patients among newcomers (Slavic ethnics). Mutations BRCA1 5382insC were detected only in women from Slavic ethnic groups. The frequency of BRCA1 5382insC mutation was 6% in the group where family history was excluded and 14% in the group of patients with characteristics of family cancer. Allele BRCA1 5382insC was not found in indigenous breast cancer patients, although 59 patients had signs of hereditary cancer. In women from Slavic ethnic group, the BRCA1 185delAG, BRCA1 4153delAG and BRCA1 T300G mutations were detected in 9.1% of cases and were not found in patients among the indigenous population. Conclusion: studies of mutations in the BRCA1 gene in breast cancer patients from Siberia confirmed data on the high frequency of «founder mutation» BRCA1 5382insC in Slavic population and indicate the advisability of further studies to identify the genes responsible for the occurrence of hereditary breast cancer in the indigenous population. Обоснование: этническая разнородность населения Сибири предполагает наличие разных наследственных мутаций в генах BRCA1/2, ассоциированных с раком молочной железы (РМЖ) и раком яичников в различных популяциях, спектр которых не изучен. Цель исследования: оценить частоту встречаемости наиболее распространенных в РФ мутаций BRCA1/2 (BRCA1 5382insC, BRCA1 185delAG, BRCA1 4153delAG, BRCA1 T300G, BRCA2 6174delT) у представительниц коренного и пришлого населения Сибири. Методы: протестирован 1281 образец геномной ДНК на наличие распространенных мутаций у больных с диагнозом РМЖ. Результаты: из 765 больных РМЖ славянской принадлежности 27 человек (3,5%) были носителями аллеля BRCA1 5382insC. Частота мутации у пациенток с признаками наследственного рака составила: у молодых пациенток до 40 лет — 8,3%, у пациенток с билатеральным раком — 20,0%, при отягощенном семейном анамнезе — 5,7%. На наличие мутации BRCA15382insC протестировано 516 больных РМЖ из Агинского бурятского автономного округа, республик Тыва и Алтай, из них 319 женщин пришлого населения (славянки) и 197 представительниц коренного населения (бурятки, тувинки, алтайки). Мутации обнаружены только у славянок, частота без учета семейного анамнеза составила 6%, с учетом признаков семейного рака — около 14%. У больных РМЖ коренного населения мутация не обнаружена, хотя 59 пациенток имеют признаки наследственного рака. Мутации BRCA1 185delAG, BRCA1 4153delAG и BRCA1 T300G выявлены у славянок в 6,7% случаев и не выявлены у представительниц коренного населения. Заключение: получены данные о высокой частоте встречаемости «мутации-основателя» 5382insC у больных РМЖ славянской популяции и отсутствии «славянских» мутаций у больных РМЖ женщин монголоидного происхождения. Актуальны исследования по выявлению генов наследственного рака молочной железы у представительниц коренного населения.
Current status of turbulent dynamo theory: From large-scale to small-scale dynamos
Several recent advances in turbulent dynamo theory are reviewed. High
resolution simulations of small-scale and large-scale dynamo action in periodic
domains are compared with each other and contrasted with similar results at low
magnetic Prandtl numbers. It is argued that all the different cases show
similarities at intermediate length scales. On the other hand, in the presence
of helicity of the turbulence, power develops on large scales, which is not
present in non-helical small-scale turbulent dynamos. At small length scales,
differences occur in connection with the dissipation cutoff scales associated
with the respective value of the magnetic Prandtl number. These differences are
found to be independent of whether or not there is large-scale dynamo action.
However, large-scale dynamos in homogeneous systems are shown to suffer from
resistive slow-down even at intermediate length scales. The results from
simulations are connected to mean field theory and its applications. Recent
work on helicity fluxes to alleviate large-scale dynamo quenching, shear
dynamos, nonlocal effects and magnetic structures from strong density
stratification are highlighted. Several insights which arise from analytic
considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue
"Magnetism in the Universe" (ed. A. Balogh
Enhanced Group Analysis and Exact Solutions of Variable Coefficient Semilinear Diffusion Equations with a Power Source
A new approach to group classification problems and more general
investigations on transformational properties of classes of differential
equations is proposed. It is based on mappings between classes of differential
equations, generated by families of point transformations. A class of variable
coefficient (1+1)-dimensional semilinear reaction-diffusion equations of the
general form () is studied from the
symmetry point of view in the framework of the approach proposed. The singular
subclass of the equations with is singled out. The group classifications
of the entire class, the singular subclass and their images are performed with
respect to both the corresponding (generalized extended) equivalence groups and
all point transformations. The set of admissible transformations of the imaged
class is exhaustively described in the general case . The procedure of
classification of nonclassical symmetries, which involves mappings between
classes of differential equations, is discussed. Wide families of new exact
solutions are also constructed for equations from the classes under
consideration by the classical method of Lie reductions and by generation of
new solutions from known ones for other equations with point transformations of
different kinds (such as additional equivalence transformations and mappings
between classes of equations).Comment: 40 pages, this is version published in Acta Applicanda Mathematica
- …