Six-loop ε\varepsilon expansion study of three-dimensional nn-vector model with cubic anisotropy

The six-loop expansions of the renormalization-group functions of $\varphi^4$ $n$-vector model with cubic anisotropy are calculated within the minimal subtraction (MS) scheme in $4 - \varepsilon$ dimensions. The $\varepsilon$ expansions for the cubic fixed point coordinates, critical exponents corresponding to the cubic universality class and marginal order parameter dimensionality $n_c$ separating different regimes of critical behavior are presented. Since the $\varepsilon$ expansions are divergent numerical estimates of the quantities of interest are obtained employing proper resummation techniques. The numbers found are compared with their counterparts obtained earlier within various field-theoretical approaches and by lattice calculations. In particular, our analysis of $n_c$ strengthens the existing arguments in favor of stability of the cubic fixed point in the physical case $n = 3$

Renormalization-group approach to the stochastic Navier--Stokes equation: Two-loop approximation

The field theoretic renormalization group is applied to the stochastic Navier--Stokes equation that describes fully developed fluid turbulence. The complete two-loop calculation of the renormalization constant, the $\beta$ function, the fixed point and the ultraviolet correction exponent is performed. The Kolmogorov constant and the inertial-range skewness factor, derived to second order of the \eps expansion, are in a good agreement with the experiment. The possibility of the extrapolation of the \eps expansion beyond the threshold where the sweeping effects become important is demonstrated on the example of a Galilean-invariant quantity, the equal-time pair correlation function of the velocity field. The extension to the $d$-dimensional case is briefly discussed.Comment: 20 pages, 3 figure

An improved \eps expansion for three-dimensional turbulence: two-loop renormalization near two dimensions

An improved \eps expansion in the $d$-dimensional ($d > 2$) stochastic theory of turbulence is constructed at two-loop order which incorporates the effect of pole singularities at $d \to 2$ in coefficients of the \eps expansion of universal quantities. For a proper account of the effect of these singularities two different approaches to the renormalization of the powerlike correlation function of the random force are analyzed near two dimensions. By direct calculation it is shown that the approach based on the mere renormalization of the nonlocal correlation function leads to contradictions at two-loop order. On the other hand, a two-loop calculation in the renormalization scheme with the addition to the force correlation function of a local term to be renormalized instead of the nonlocal one yields consistent results in accordance with the UV renormalization theory. The latter renormalization prescription is used for the two-loop renormalization-group analysis amended with partial resummation of the pole singularities near two dimensions leading to a significant improvement of the agreement with experimental results for the Kolmogorov constant.Comment: 23 pages, 2 figure

Renormalization group in the infinite-dimensional turbulence: third-order results

The field theoretic renormalization group is applied to the stochastic Navier-Stokes equation with the stirring force correlator of the form k^(4-d-2\epsilon) in the d-dimensional space, in connection with the problem of construction of the 1/d expansion for the fully developed fluid turbulence beyond the scope of the standard epsilon expansion. It is shown that in the large-d limit the number of the Feynman diagrams for the Green function (linear response function) decreases drastically, and the technique of their analytical calculation is developed. The main ingredients of the renormalization group approach -- the renormalization constant, beta function and the ultraviolet correction exponent omega, are calculated to order epsilon^3 (three-loop approximation). The two-point velocity-velocity correlation function, the Kolmogorov constant C_K in the spectrum of turbulent energy and the inertial-range skewness factor S are calculated in the large-d limit to third order of the epsilon expansion. Surprisingly enough, our results for C_K are in a reasonable agreement with the existing experimental estimates.Comment: 30 pages with EPS figure

Measurements of integral muon intensity at large zenith angles

High-statistics data on near-horizontal muons collected with Russian-Italian coordinate detector DECOR are analyzed. Precise measurements of muon angular distributions in zenith angle interval from 60 to 90 degrees have been performed. In total, more than 20 million muons are selected. Dependences of the absolute integral muon intensity on zenith angle for several threshold energies ranging from 1.7 GeV to 7.2 GeV are derived. Results for this region of zenith angles and threshold energies have been obtained for the first time. The dependence of integral intensity on zenith angle and threshold energy is well fitted by a simple analytical formula.Comment: 4 pages, 4 figures, 1 tabl

An improved \eps expansion for three-dimensional turbulence: summation of nearest dimensional singularities

An improved \eps expansion in the $d$-dimensional ($d > 2$) stochastic theory of turbulence is constructed by taking into account pole singularities at $d \to 2$ in coefficients of the \eps expansion of universal quantities. Effectiveness of the method is illustrated by a two-loop calculation of the Kolmogorov constant in three dimensions.Comment: 4 page

Tunka Advanced Instrument for cosmic rays and Gamma Astronomy

The paper is a script of a lecture given at the ISAPP-Baikal summer school in 2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) facility including historical introduction, description of existing and future setups, and outreach and open data activities.Comment: Lectures given at the ISAPP-Baikal Summer School 2018: Exploring the Universe through multiple messengers, 12-21 July 2018, Bol'shie Koty, Russi

К вопросу дифференциальной диагностики листериоза

A clinical example shows the erroneous diagnosis of listeriosis in a 15-year-old child hospitalized in the infectious department. The child was admitted with severe symptoms of intoxication, febrile fever, difficulty in nasal breathing, hyperemia of the mucous membranes of the oropharynx, tonsillitis, cervical lymphadenitis, facial tissue pasteness with swelling of the eyelid and conjunctivitis of the left eye, hepatosplenomegaly. A laboratory examination revealed pronounced leukocytosis up to 24 thousand, lymphocytosis, atypical mononuclear cells up to 9%, IgM and IgG to EBV capsid protein, IgM to CMV, IgM and IgG to listeria. But with a repeated double study of IgM and IgG to Listeria were not detected. The initial positive result was possibly due to the presence of cross-reacting antibodies in EBV mononucleosis. The final diagnosis was made: Infectious mononucleosis of mixed (EBV, CMV) etiology. Chronic polypous rhinosinusitis, exacerbation. Reactive edema of the eyelids against the background of inflammation of the sinuses.Given the variety of clinical forms of listeriosis and their similarity with the manifestations of other infections, for the full diagnosis of listeriosis infection, it is advisable to evaluate the epidemiological and medical history data, as well as use an extended spectrum of laboratory confirmation of the diagnosis.На клиническом примере показана ошибочная диагностика листериоза у ребенка 15 лет, госпитализированного в инфекционное отделение МДГКБ. Ребенок поступил с выраженными симптомами интоксикации, фебрильной лихорадкой, затрудненным носовым дыханием, гиперемией слизистых ротоглотки, тонзиллитом, шейным лимфаденитом, пастозностью тканей лица с отечностью века и конъюнктивитом левого глаза, гепатоспленомегалией. При лабораторном обследовании в крови выявлен выраженный лейкоцитоз до 24 тыс., лимфоцитоз, атипичные мононуклеары до 9%, обнаружены IgM и IgG к капсидному белку ЭБВ, IgM к ЦМВ, IgM и IgG к листериям. Но при повторном двукратном исследовании IgM и IgG к листериям обнаружены не были. Первоначальный положительный результат возможно был связан с наличием перекрестно реагирующих антител при ЭБВ-мононуклеозе. Был выставлен окончательный диагноз: Инфекционный мононуклеоз смешанной (ЭБВ, ЦМВ) этиологии. Хронический полипозный риносинусит, обострение. Реактивный отек век на фоне воспаления придаточных пазух носа. Учитывая разнообразие клинических форм листериоза и их сходство с проявлениями других инфекций, для полноценной диагностики листериозной инфекции целесообразно оценивать эпидемиологические, анамнестические данные, а также использовать расширенный спектр лабораторного подтверждения диагноза

Профилактика антибиотикоассоциированной диареи у детей лактосодержащим пробиотиком

The data on the frequency of the spread of antibiotic-associated diarrhea (AAD) in children. A different incidence of AAD in children of different age groups, highest in children under the age of 3 years.The possibility of reducing the frequency of its development when administered prophylactically domestic probiotic containing Lactobacillus — Acipol on the background of antibiotic therapy. Prophylactic Acipol can reduce the incidence of AAD in these patients is 21%, and reduce the duration and severity of diarrheal syndrome.Представлены данные о частоте распространения антибиотикоассоциированной диареи (ААД) у детей. Показана различная частота встречаемости ААД при ОРЗ и других заболеваниях у детей разных возрастных групп, наиболее высокая у детей в возрасте до 3-х лет.Установлена возможность снижения частоты развития ААД при профилактическом назначении отечественного лактосодержащего пробиотика Аципол на фоне антибиотикотерапии. Профилактическое назначение Аципола позволяет снизить частоту развития ААД у этих больных на 21%, а также уменьшить длительность и выраженность диарейного синдрома