Electric dipole moment enhancement factor of thallium

The goal of this work is to resolve the present controversy in the value of the EDM enhancement factor of Tl. We have carried out several calculations by different high-precision methods, studied previously omitted corrections, as well as tested our methodology on other parity conserving quantities. We find the EDM enhancement factor of Tl to be equal to -573(20). This value is 20% larger than the recently published result of Nataraj et al. [Phys. Rev. Lett. 106, 200403 (2011)], but agrees very well with several earlier results.Comment: 5 pages; v2: link to supplemental material adde

Transition frequency shifts with fine structure constant variation for Fe II: Breit and core-valence correlation correction

Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine structure constant \alpha. The resonance absorption lines of Fe II from objects at cosmological distances are used in a search for the possible variation of \alpha in cause of cosmic time. In this paper we calculated the dependence of the transition frequencies on \alpha^2 (q-factors) for Fe II ion. We found corrections to these coefficients from valence-valence and core-valence correlations and from the Breit interaction. Both the core-valence correlation and Breit corrections to the q-factors appeared to be larger than had been anticipated previously. Nevertheless our calculation confirms that the Fe II absorption lines seen in quasar spectra have large q-factors of both signs and thus the ion Fe II alone can be used in the search for the \alpha-variation at different cosmological epochs.Comment: 7 pages, submitted to Phys. Rev.

Calculation of P,T-odd electric dipole moments for diamagnetic atoms 129^{129}Xe, 171^{171}Yb, 199^{199}Hg, 211^{211}Rn, and 225^{225}Ra

Electric dipole moments of diamagnetic atoms of experimental interest are calculated using the relativistic Hartree-Fock and random-phase approximation methods, the many-body perturbation theory and configuration interaction technique. We consider P,T-odd interactions which give rise to atomic electric dipole moment in the second order of the perturbation theory. These include nuclear Schiff moment, P,T-odd electron-nucleon interaction and electron electric dipole moment. Interpretation of a new experimental constraint of a permanent electric dipole moment of $^{199}$Hg [W. C. Griffith {\it et al.}, Phys. Rev. Lett. {\bf 102}, 101601 (2009)] is discussed.Comment: 9 page

Hopping Conduction in Uniaxially Stressed Si:B near the Insulator-Metal Transition

Using uniaxial stress to tune the critical density near that of the sample, we have studied in detail the low-temperature conductivity of p-type Si:B in the insulating phase very near the metal-insulator transition. For all values of temperature and stress, the conductivity collapses onto a single universal scaling curve. For large values of the argument, the scaling function is well fit by the exponentially activated form associated with variable range hopping when electron-electron interactions cause a soft Coulomb gap in the density of states at the Fermi energy. The temperature dependence of the prefactor, corresponding to the T-dependence of the critical curve, has been determined reliably for this system, and is proportional to the square-root of T. We show explicitly that nevlecting the prefactor leads to substantial errors in the determination of the scaling parameters and the critical exponents derived from them. The conductivity is not consistent with Mott variable-range hopping in the critical region nor does it obey this form for any range of the parameters. Instead, for smaller argument of the scaling function, the conductivity of Si:B is well fit by an exponential form with exponent 0.31 related to the critical exponents of the system at the metal- insulator transition.Comment: 13 pages, 6 figure

Coupled tensorial form for atomic relativistic two-particle operator given in second quantization representation

General formulas of the two-electron operator representing either atomic or effective interactions are given in a coupled tensorial form in relativistic approximation. The alternatives of using uncoupled, coupled and antisymmetric two-electron wave functions in constructing coupled tensorial form of the operator are studied. The second quantization technique is used. The considered operator acts in the space of states of open-subshell atoms

Familial Associations of Adiposity: Findings from a Cross-Sectional Study of 12,181 Parental-Offspring Trios from Belarus

It is suggested that maternal adiposity has a stronger association with offspring adiposity than does paternal adiposity. Furthermore, a recent small study reported gender assortment in parental-offspring adiposity associations. We aimed to examine these associations in one of the largest studies to date using data from a low-middle income country that has recently undergone a major political and economic transition.In a cross-sectional study of 12,181 parental-offspring trios from Belarus (mean age (SD) of mothers 31.7 (4.9), fathers 34.1 (5.1) and children 6.6 (0.3) at time of assessment), we found positive graded associations of mother's and father's BMI with offspring adiposity. There was no evidence that these associations differed between mothers and fathers. For example, the odds ratio of offspring overweight or obesity (based on BMI) comparing obese and overweight mothers to normal weight mothers was 2.03 (95%CI 1.77, 2.31) in fully adjusted models; the equivalent result for father's overweight/obesity was 1.81 (1.58, 2.07). Equivalent results for offspring being in the top 10% waist circumference were 1.91 (1.67, 2.18) comparing obese/overweight to normal weight mothers and 1.72 (1.53, 1.95) comparing obese/overweight to normal weight fathers. Similarly, results for offspring being in the top 10% of percent fat mass were 1.58 (1.36, 1.84) and 1.76 (1.49, 2.07), for mother's and father's obese/overweight exposures respectively. There was no strong or consistent evidence of gender assortment--i.e. associations of maternal adiposity exposures with offspring outcomes were similar in magnitude for their daughters compared to equivalent associations in their sons and paternal associations were also similar in sons and daughters.These findings suggest that genetic and/or shared familial environment explain family clustering of adiposity. Interventions aimed at changing overall family lifestyle are likely to be important for population level obesity prevention

Сорбционно-структурные свойства аэрогельных материалов на основе биополимеров

В настоящее время для выведения избыточного количества тяжелых металлов и токсинов из живых организмов успешно применяются аэрогельные материалы в качестве энтеро- и апликационных сорбентов. Неисчерпаемой сырьевой базой для создания аэрогельных материалов являются природные биополимеры альгинат и хитозан, а также различные производные лигнина. На их основе разработано значительное количество сорбционных материалов и раневых покрытий различных типов, что связано не только с широким спектром физико-химических свойств названных полимеров и их уже доказанной медико-биологической активностью, но и с распространенностью и возобновляемостью сырьевых источников для производства данных полимеров, простотой извлечения, возможностью достижения высокой степени очистки и сравнительно невысокой ценой. Ключевой стадией синтеза аэрогельных материалов является формирование прочного гидрогеля – каркаса. Один из технологических приемов – получение интерполиэлектролитного армирующего гидрогеля. В работе предложены 2 упаковочные модели формирования структуры интерполиэлектролитных комплексов на основе пар биополимеров: «альгинат натрия – хитозан» и «лигносульфонат натрия – хитозан». Первая модель – блочная, при которой структура формируется за счет ионных связей между карбоксильными группами альгината натрия и аминогруппами хитозана, а также кооперативной системы водородных связей и дисперсионных взаимодействий. Вторая модель – агрегационно-трубчатая, структура которой образуется посредством ионных связей между сульфогруппами (в составе палочкообразных надмолекулярных структур лигносульфоната натрия) и аминогруппами хитозана, а также водородных связей и дисперсионных взаимодействий. При высушивании интерполиэлектролитных комплексов в сверхкритических условиях формируются прочные фазовые контакты, при этом изменения в структуре геля становятся необратимыми. В результате получены гидрофобные микро- и мезопористые 2-компонентные аэрогельные материалы, различающиеся внутренней структурой. Аэрогельные материалы, структура которых образована по 1-й из названных моделей, характеризуются фибриллярной структурой, а по 2-й ‒ структурными элементами сферической формы. Полученные аэрогельные материалы обладают высокой сорбционной активностью по отношению к воде и широкому кругу тяжелых металлов и низкомолекулярных токсинов. Цель работы – исследование структурно-сорбционных свойств аэрогельных материалов, основа которых – биополимеры различной структурной организации. Значительное увеличение сорбционной активности аэрогельных материалов «альгинат натрия – хитозан» в сравнении с «лигносульфонат натрия – хитозан» связано, по-видимому, с их различной надмолекулярной структурой. Действует совокупность механизмов сорбции: намокание, всасывание, диффузия, осмотические явления и химическое взаимодействие, обусловленное высокопористой структурой аэрогельных материалов и наличием сорбционно-активных центров. Для цитирования: Бровко О.С., Паламарчук И.А., Горшкова Н.А., Богданович Н.И., Ивахнов А.Д. Сорбционно-структурные свойства аэрогельных материалов на основе биополимеров // Изв. вузов. Лесн. журн. 2023. № 6. С. 190–203. https://doi.org/10.37482/0536-1036-2023-6-190-20

Conductivity of Metallic Si:B near the Metal-Insulator Transition: Comparison between Unstressed and Uniaxially Stressed Samples

The low-temperature dc conductivities of barely metallic samples of p-type Si:B are compared for a series of samples with different dopant concentrations, n, in the absence of stress (cubic symmetry), and for a single sample driven from the metallic into the insulating phase by uniaxial compression, S. For all values of temperature and stress, the conductivity of the stressed sample collapses onto a single universal scaling curve. The scaling fit indicates that the conductivity of si:B is proportional to the square-root of T in the critical range. Our data yield a critical conductivity exponent of 1.6, considerably larger than the value reported in earlier experiments where the transition was crossed by varying the dopant concentration. The larger exponent is based on data in a narrow range of stress near the critical value within which scaling holds. We show explicitly that the temperature dependences of the conductivity of stressed and unstressed Si:B are different, suggesting that a direct comparison of the critical behavior and critical exponents for stress- tuned and concentration-tuned transitions may not be warranted

Nomenclatural standards and genetic certificates for apple-tree cultivars developed at the North Caucasian Federal Scientific Center of Horticulture, Viticulture, wine-making

Background. The development of genetic certificates and nomenclatural standards for newly released cultivars of Malus domestica Borkh. (apple tree) ensures an opportunity to preserve the original and authentic genetic and morphological information on domestic cultivars promising for the south of Russia. The purpose of this study was to develop genetic certificates and nomenclatural standards for 7 apple-tree cultivars developed at the North Caucasian Federal Scientific Center of Horticulture, Viticulture, Wine-making (NCFSCHVW), five of which were released jointly with the All-Russian Research Institute of Fruit Crop Breeding (VNIISPK).Materials and methods. The materials included apple-tree cultivars resistant or immune to scab (Venturia inaequalis (Cooke) G. Winter) from the NCFSCHVW collection stock. Conventional herbarization and DNA fingerprinting methods were used. For cultivar certification, an improved technique of DNA sampling and 12 microsatellite markers were applied.Results. Unique DNA profile certificates and nomenclatural standards were produced for 7 apple-tree cultivars: ‘Vasilisa’, ‘Karmen’, ‘Krasny Yantar’, ‘Soyuz’ and ‘Rassvet’ (with the Rvi6 gene) released jointly by the NCFSCHVW and VNIISPK, plus ‘Zolotoye Letneye’ and ‘Feya’ developed at the NCFSCHVW. The apple-tree herbarium specimens were placed for perpetual storage in the WIR Herbarium of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR).Conclusion. The results obtained are promising for identification and authenticity verification of new domestic apple-tree cultivars during their reproduction and cultivation

Scaling of the Conductivity with Temperature and Uniaxial Stress in Si:B at the Metal-Insulator Transition

Using uniaxial stress to tune Si:B through the metal-insulator transition we find the conductivity at low temperatures shows an excellent fit to scaling with temperature and stress on both sides of the transition. The scaling functions yield the conductivity in the metallic and insulating phases, and allow a reliable determination of the temperature dependence in the critical regions on both sides of the transition