On Compound Poisson Processes Arising in Change-Point Type Statistical Models as Limiting Likelihood Ratios

Different change-point type models encountered in statistical inference for stochastic processes give rise to different limiting likelihood ratio processes. In a previous paper of one of the authors it was established that one of these likelihood ratios, which is an exponential functional of a two-sided Poisson process driven by some parameter, can be approximated (for sufficiently small values of the parameter) by another one, which is an exponential functional of a two-sided Brownian motion. In this paper we consider yet another likelihood ratio, which is the exponent of a two-sided compound Poisson process driven by some parameter. We establish, that similarly to the Poisson type one, the compound Poisson type likelihood ratio can be approximated by the Brownian type one for sufficiently small values of the parameter. We equally discuss the asymptotics for large values of the parameter and illustrate the results by numerical simulations

Minimax estimation of the Wigner function in quantum homodyne tomography with ideal detectors

We estimate the quantum state of a light beam from results of quantum homodyne measurements performed on identically prepared pulses. The state is represented through the Wigner function, a ``quasi-probability density'' on $\mathbb{R}^{2}$ which may take negative values and must respect intrinsic positivity constraints imposed by quantum physics. The data consists of $n$ i.i.d. observations from a probability density equal to the Radon transform of the Wigner function. We construct an estimator for the Wigner function, and prove that it is minimax efficient for the pointwise risk over a class of infinitely differentiable functions. A similar result was previously derived by Cavalier in the context of positron emission tomography. Our work extends this result to the space of smooth Wigner functions, which is the relevant parameter space for quantum homodyne tomography.Comment: 15 page

CFD model of acceleration of thermal-hydrodynamic processes in solar air collectors

Recent studies on increasing the thermal-hydrodynamic efficiency of solar air collectors have been carried out on the installation of barriers of various shapes on the surface of the absorber, and this method ensures a significant increase in the energy efficiency of the collector. The transfer of the air flow washing the surface of the absorber from a laminar flow state to an accelerated lumped air flow is carried out by installing obstacles. Installation of barriers is the main factor in increasing the heat transfer in solar air collectors and prolongs the time of air flow in the collector. The barrier solar air collector has a high local heat transfer coefficient, and the Nusselt number value is up to 3.5 times higher than that of the flat plate solar air collector. Also, this article presents the results of CFD modeling of the air flow in the solar air collector, the results of which can be used in the theoretical research of the solar air collector

Mesenchymal stromal/stem cells and their exosomes for restoration of spermatogenesis in non-obstructive azoospermia: a systemic review

Stem cells have been introduced as new promising therapeutic agents in treatment of degenerative diseases because of having high differentiation potential while maintaining the ability to self-replicate and retaining features of their source cells. Among different type of cell therapies, mesenchymal stromal/stem cell (MSC) therapy is being increasingly developed as a new way to treat structural defects that need to be repaired and regenerated. Non-obstructive azoospermia (NOA) is a reproductive disease in men that causes infertility in 10% of infertile men. Based on in vitro studies, MSCs from different tissue sources have been differentiated into germ cells or gamete progenitor cells by simple methods in both male and female. On the other hand, the therapeutic effects of MSCs have been evaluated for the treatment of NOA animal models created by chemical or surgical compounds. The results of these studies confirmed successful allotransplantation or xenotransplantation of MSCs in the seminiferous tubules. As well, it has been reported that exosomes secreted by MSCs are able to induce the process of spermatogenesis in the testes of infertile animal models. Despite numerous advances in the treatment of reproductive diseases in men and women with the help of MSCs or their exosomes, no clinical trial has been terminated on the treatment of NOA. This systematic review attempts to investigate the possibility of MSC therapy for NOA in men

Relationship of Racial Residential Segregation to Newly Diagnosed Cases of HIV among Black Heterosexuals in US Metropolitan Areas, 2008–2015

Social science and public health literature has framed residential segregation as a potent structural determinant of the higher HIV burden among black heterosexuals, but empirical evidence has been limited. The purpose of this study is to test, for the first time, the association between racial segregation and newly diagnosed heterosexually acquired HIV cases among black adults and adolescents in 95 large US metropolitan statistical areas (MSAs) in 2008–2015. We operationalized racial segregation (the main exposure) using Massey and Denton’s isolation index for black residents; the outcome was the rate of newly diagnosed HIV cases per 10,000 black adult heterosexuals. We tested the relationship of segregation to this outcome using multilevel multivariate models of longitudinal (2008–2015) MSA-level data, controlling for potential confounders and time. All covariates were lagged by 1 year and centered on baseline values. We preliminarily explored mediation of the focal relationship by inequalities in education, employment, and poverty rates. Segregation was positively associated with the outcome: a one standard deviation decrease in baseline isolation was associated with a 16.2% reduction in the rate of new HIV diagnoses; one standard deviation reduction in isolation over time was associated with 4.6% decrease in the outcome. Exploratory mediation analyses suggest that black/white socioeconomic inequality may mediate the relationship between segregation and HIV. Our study suggests that residential segregation may be a distal determinant of HIV among black heterosexuals. The findings further emphasize the need to address segregation as part of a comprehensive strategy to reduce racial inequities in HIV

Continuous Symmetries of Difference Equations

Lie group theory was originally created more than 100 years ago as a tool for solving ordinary and partial differential equations. In this article we review the results of a much more recent program: the use of Lie groups to study difference equations. We show that the mismatch between continuous symmetries and discrete equations can be resolved in at least two manners. One is to use generalized symmetries acting on solutions of difference equations, but leaving the lattice invariant. The other is to restrict to point symmetries, but to allow them to also transform the lattice.Comment: Review articl

Модели макросейсмического поля землетрясений Центральной Азии и их влияние на результирующие оценки сейсмической опасности

Seismic intensity assessment in points of a macroseismic scale plays an important role for researching the seismic history of areas characterized by active seismicity, as well as for construction (and updating) of seismic zoning maps in various scales. Macroseismic scale points are generally referred to in construction standards applied in the majority of post-Soviet states. In our study aimed to model the macroseismic field of earthquakes, a large volume of macroseismic data on Central Asia was analyzed, and coefficients used in Blake–Shebalin and Covesligeti equations were aligned. This article presents a generalized dependence model of macroseismic intensity attenuation with distance. The model takes into account seismic load features determined by various depths of earthquakes. The ratios of small and big axes of the ellipse, that approximates real isoseists, are estimated with respect to seismic scale points, earthquake depths and magnitudes. The East Uzbekistan area is studied as an example to investigate whether seismic hazard assessment values may differ depending on a chosen law of seismic influence intensity attenuation with distance.Оценка интенсивности сейсмических воздействий в баллах макросейсмической шкалы играет важную роль как для исследования исторической сейсмичности сейсмоактивных территорий, так и для составления и уточнения разномасштабных карт сейсмического районирования, поскольку строительные нормы большинства стран постсоветского пространства опираются именно на эту характеристику сейсмических воздействий. Целью исследования является построение адекватной модели макросейсмического поля землетрясений Центральной Азии. В статье на основе большого объема макросейсмических данных, наряду с уточнением коэффициентов в уравнениях типа Блейка – Шебалина и Ковеслигети для территории Центральной Азии, предложена обобщенная зависимость затухания макросейсмической интенсивности с расстоянием с учетом особенностей сейсмических воздействий, обусловленных различной глубиной происходящих землетрясений. Получены соотношения между малой и большой осями эллипса, аппроксимирующего реальные изосейсты, в зависимости от балльности сотрясения, глубины и магнитуды землетрясения. На примере территории Восточного Узбекистана исследован вопрос о влиянии выбора закона затухания интенсивности сейсмических воздействий с расстоянием на результирующие оценки сейсмической опасности

Предикторы улучшения качества жизни пациентов с хроническими окклюзиями коронарных артерий в зависимости от тактики ведения

Highlights. The impact of clinical, angiographic and procedure-related factors on the quality of life of patients with chronic coronary total occlusions has been reported.Background. The impact of patient-related factors including clinical and angiographic data and procedure-related factors on the quality of life remains debating.Aim. To assess the impact of baseline and procedure-related factors on the quality of life in patients with chronic coronary total occlusion.Methods. 140 patients with chronic single-vessel disease randomly assigned either to the invasive-strategy group or the conservative-strategy group. Quality of life was measured in all patients using the Seattle Angina Questionnaire, European Quality of Life Survey, and Rose Dyspnea Scale after 3 and 12 months. To determine the predictors to the quality of life improvements in both groups, simple and multivariate regression analysis were performed. The baseline clinical, angiographic and procedure-related factors were included in the analysis.Results. The technical success of the procedure was the independent predictor to quality of life improvement in the invasive-strategy group (OR: 5.8, 95%, CI: 3,26-9.18, p = 0.001). The absence of diabetes mellitus (OR: 0.19, 95%, CI: 0.09-0.84, p = 0.04), CTO of other than left anterior descending artery (OR: 2.1, 95%, CI: 1.09-4.0, p = 0.03) and higher SAQ - 7 score at baseline (OR: 1.1, 95%, CI: 1.04-1.21, p = 0.02) independently predicted the improvements in the quality of life. The indicators of quality of life between the subgroups of subintimal and intraluminal recanalization did not differ significantly in the long-term period. The total SAQ-7 score in the subintimal recanalization subgroup was 85.5 ± 9.1 versus 89.3 ± 9.6 in the intraluminal recanalization subgroup (p = 0.21).Conclusion. The decision on the management of patients with chronic coronary total occlusions should be made individually, taking into account baseline clinical and instrumental data. The recanalization technique does not affect the quality of life. Its choice should be made individually in order to achieve technical success.Основные положения. В статье проанализировано влияние клинических, ангиографических и процедурных характеристик на показатели качества жизни пациентов с хроническими окклюзиями коронарных артерий.Актуальность. До сих пор неизвестно, могут ли характеристики (клинические и ангиографические) пациента и процедуры влиять на качество жизни.Цель. Оценить влияние исходных и процедурных факторов на показатели качества жизни пациентов с хроническими окклюзиями коронарных артерий (ХОКА).Материалы и методы. В исследование включены 140 пациентов с однососудистой ХОКА, случайно распределенных в группу инвазивной или консервативной стратегий лечения. Через 3 и 12 мес. у всех больных оценивали качество жизни по данным сиэтловского, европейского опросников и шкалы одышки Rose. Для определения предикторов улучшения качества жизни в обеих группах проводили одно- и многофакторный регрессионный анализы. Учитывали исходные клинические, ангиографические и процедурные (в группе инвазивного лечения) характеристики больных.Результаты. В группе инвазивного подхода независимым предиктором улучшения качества жизни являлся технический успех процедуры (отношение шансов, ОШ, 5,8; 95% доверигельный интервал, ДИ 3,26-9,18; p = 0,001), в группе консервативного - отсутствие сахарного диабета (ОШ 0,19, 95% ДИ 0,09-0,84; p = 0,04), локализация ХОКА не в бассейне передней нисходящей артерии (ОШ 2,1, 95% ДИ 1,09-4,0; p = 0,03) и исходно более высокий суммарный балл по SAQ-7 (ОШ 1,1, 95% ДИ 1,04-1,21; p = 0,02). Показатели качества жизни в группах субинтимальной и внутрипросветной методик реканализации ХОКА в отдаленном периоде статистически значимо не отличались: суммарный балл по SAQ-7 в группе субинтимальной реканализации составил 85,5±9,1, в группе внутрипросветной реканализации - 89,3±9,6; p = 0,21.Заключение. Решение вопроса о выборе стратегии ведения пациентов с ХОКА следует принимать с учетом исходных клинико-инструментальных данных. Методика реканализации не влияет на показатели качества жизни, ее выбор должен осуществляться индивидуально с целью достижения технического успеха

Regularity Properties and Pathologies of Position-Space Renormalization-Group Transformations

We reconsider the conceptual foundations of the renormalization-group (RG) formalism, and prove some rigorous theorems on the regularity properties and possible pathologies of the RG map. Regarding regularity, we show that the RG map, defined on a suitable space of interactions (= formal Hamiltonians), is always single-valued and Lipschitz continuous on its domain of definition. This rules out a recently proposed scenario for the RG description of first-order phase transitions. On the pathological side, we make rigorous some arguments of Griffiths, Pearce and Israel, and prove in several cases that the renormalized measure is not a Gibbs measure for any reasonable interaction. This means that the RG map is ill-defined, and that the conventional RG description of first-order phase transitions is not universally valid. For decimation or Kadanoff transformations applied to the Ising model in dimension $d \ge 3$, these pathologies occur in a full neighborhood $\{ \beta > \beta_0 ,\, |h| < \epsilon(\beta) \}$ of the low-temperature part of the first-order phase-transition surface. For block-averaging transformations applied to the Ising model in dimension $d \ge 2$, the pathologies occur at low temperatures for arbitrary magnetic-field strength. Pathologies may also occur in the critical region for Ising models in dimension $d \ge 4$. We discuss in detail the distinction between Gibbsian and non-Gibbsian measures, and give a rather complete catalogue of the known examples. Finally, we discuss the heuristic and numerical evidence on RG pathologies in the light of our rigorous theorems.Comment: 273 pages including 14 figures, Postscript, See also ftp.scri.fsu.edu:hep-lat/papers/9210/9210032.ps.

Basic properties of the preparation "Loramor" in the complex treatment of purulent-inflammatory diseases of the objective facial region

The article reflects the results of the study of the main properties of the drug "Loramor" in the complex treatment of purulent-inflammatory diseases of the maxillofacial region (МFR) among patients who were treated in the department of maxillofacial surgery of the city medical association of Samarkand. The results of the study prove the effectiveness of the use of the drug "Loramor" in the complex treatment of purulent-inflammatory diseases of the maxillofacial region.В статье отражены результаты исследования основных свойств препарата «Лорамор» в комплексном лечении гнойно-воспалительных заболеваний челюстно-лицевой области среди пациентов,находившихся на лечении в отделении челюстно-лицевой хирургии Самаркандского городского медицинского объединения. Полученные результаты исследования доказывают эффективность использования препарата «Лорамор» в комплексном лечении гнойно-воспалительных заболеваний челюстно-лицевой области