The Angstrom Project Alert System: real-time detection of extragalactic microlensing

The Angstrom Project is undertaking an optical survey of stellar microlensing events across the bulge region of the Andromeda Galaxy (M31) using a distributed network of two-meter class telescopes. The Angstrom Project Alert System (APAS) has been developed to identify in real time candidate microlensing and transient events using data from the Liverpool and Faulkes North robotic telescopes. This is the first time that real-time microlensing discovery has been attempted outside of the Milky Way and its satellite galaxies. The APAS is designed to enable follow-up studies of M31 microlensing systems, including searches for gas giant planets in M31. Here we describe the APAS and we present a few example light curves obtained during its commissioning phase which clearly demonstrate its real-time capability to identify microlensing candidates as well as other transient sources.Comment: 4 pages, submitted to ApJ Letter

Риски хирургического лечения глаукомы на единственном видящем глазу с далекозашедшей стадией заболевания

This review summarizes the results of surgical treatment of far-advanced stage glaucoma in the only seeing eye. A literature search performed in the PubMed search engine and aimed at finding publications reporting the clinical outcomes of treatment in patients with glaucoma in the only seeing eye did yield sufficient data related to the topic. A comprehensive analysis of the available data was performed with an emphasis on the choice of treatment tactics and postoperative results at various times following a surgery. Several studies allowed to perform a comparison of the clinical advantages and cost-effectiveness of medical treatment versus surgery for advanced glaucoma, as well as to assess potential risks and adverse outcomes such as glaucoma progression, postoperative scarring, hypotension and other complications. The results presented in this review suggest that common success criteria can provide uniformity in academic studies, but in daily clinical practice each glaucoma specialist must make a patient-specific decision in favor of either of these methods of treatment in order to guarantee an optimal result, both for the doctor and, of course, for the patient.Цель обзора — обобщить результаты, полученные после проведенного хирургического лечения далекозашедшей стадии глаукомы на единственно видящем глазу. Поиск литературы, выполненный в поисковой системе PubMed и направленный на обнаружение публикаций, сообщающих о клинических результатах проведенного лечения у пациентов с глаукомой на единственно видящем глазу, не позволил нам найти достаточного объема такого рода исследований. Проведен всесторонний анализ имеющихся данных с акцентом на выбор тактики лечения и послеоперационные результаты в различные сроки после операции. Некоторые исследования позволили сравнить клиническую и экономическую эффективность медикаментозного лечения по сравнению с хирургическим лечением далекозашедшей стадии глаукомы, а также оценить вероятные риски и неблагоприятные исходы, такие как прогрессирование глаукомы, послеоперационное рубцевание, гипотонию и другие осложнения. Результаты, представленные в обзоре, позволяют сделать вывод, что общие критерии успеха могут обеспечить однородность в академических исследованиях, но в повседневной клинической практике каждый глаукоматолог должен индивидуально принимать решение в пользу того или иного метода лечения, чтобы гарантировать оптимальный результат, как для врача, так и, естественно, для пациента

Timing of AR CrB eclipses

AR CrB is a short-period low-mass eclipsing binary. We conducted photometric observations of the system in 2013, 2014, 2016, 2017, and obtained times of its light curves minima. The timing of eclipses (our times of minima combined with data from the literature) shows that the orbital period of AR CrB could possess periodical variations that can be explained by the gravitational influence of a third companion in a highly eccentric orbit around the central binary

Распространение и сезонная динамика токсокароза у собак в Республике Таджикистан

The purpose of the research is to study the spread and seasonal dynamics of toxocarosis in domestic and police dogs in the Republic of Tajikistan.Materials and methods. In order to study the period of maximum Toxocara sp. infection and seasonal dynamics of toxocarosis, monthly records were kept for dogs diagnosed with toxocarosis in a population of both domestic and police dogs from September 2016 to February 2019. We examined 70 dogs, of these 41 were police dogs and 29 were domestic dogs. 334 fecal specimens of police dogs and 221 fecal specimens of domestic dogs were examined by the Fulleborn flotation method.Results and discussion. 75 (22.3%) fecal specimens of police dogs from 336 fecal specimens studied were found to have Toxocara sp. eggs, and Toxocara sp. eggs were found in 28 (12.6%) fecal specimens of domestic dogs from 221 dogs studied. Toxocarosis in domestic dogs was reported throughout the year. The maximum Toxocara sp. infection in dogs was established in winter (28.5%) and summer (29.6%) 2017, and in summer (38.0%) and spring (31.8%) 2018, and in spring (28.5%) 2019. Toxocara sp. occurrence in police dogs and dogs belonging to breeding kennels of various institutions accounts for 4–8 age group. Dogs of younger age were infected with Toxocara sp. to a lesser degree.Цель исследований: изучить распространение и сезонную динамику токсокароза среди домашних и служебных собак в Республике Таджикистан.Материалы и методы. Для изучения периода максимального инвазирования токсокарами и сезонной динамики токсокароза проводили ежемесячный учет собак с диагнозом на токсокароз с сентября 2016 по февраль 2019 гг. как в популяции домашних, так и служебных собак. Всего было исследовано 70 собак, из них 41 служебная и 29 домашних собак. Исследовано 334 проб фекалий служебных и 221 – домашних собак методом флотации по Фюллеборну.Результаты и обсуждение. В 75 (22,3%) пробах фекалий служебных собак из 336 исследованных обнаружены яйца токсокар, а в 221 пробе фекалий домашних собак яйца токсокар обнаружены в 28 (12,6%). Токсокароз у домашних собак регистрировали в течение всего года. В 2017 г. наибольшая инвазированность собак токсокарами установлена в зимний (28,5%) и летний (29,6%) периоды, в 2018 г. – в летний (38,0%) и весенний (31,8%), в 2019 г. – в весенний (28,5%) период. Заболеваемость токсокарами среди служебных и собак, принадлежащих питомникам различных учреждений, приходится на возрастную группу 4–8 лет. Собаки младшего возраста были заражены токсокарами в меньшей степени

Drainage surgery for primary open-angle glaucoma: past, present, future

Relevance. Despite many techniques for reducing intraocular pressure, surgical treatment of glaucoma has limited effectiveness. First, due to excessive scarring of new intraocular fluid outflow pathways and second, antifibrotics medicaments are unable to effectively control wound healing. The use of drainages reduces the risk of excessive scarring in the area of the filtration pad and forms several ways of outflow of intraocular fluid. The review presents the following sections: development history, advantages, disadvantages, surgical technique and promising directions of glaucoma drainage surgery.Purpose. Summarizing data on the possibility of drainage surgery, historical aspects, causes of scarring and methods of dealing with them. Provide data on various modern drainage devices that are used not only in Russia and their effectiveness.Material and methods. To perform the review, we searched for literature sources on the abstract databases E-library, PubMed and Scopus for the period up to and including 2018, using the keywords «glaucoma drainage surgery» (in the E-library database), «anti-glaucoma drainage» and «anti-glaucoma drainage device» (in the PubMed and Scopus databases). Abstracts of conferences were excluded from the review. A total of 40 articles related to the review topic were identified. The beginning of publications on this issue in domestic sources dates back to 1970, and in foreign sources to 1987.Results. The review presents the history of development, advantages, disadvantages of surgical techniques and promising areas of glaucoma drainage surgery. Various models of drainage devices, as well as their specific and non-specific complications are described. The effectivenes of various valves were 70%, with an average decrease in the level of IOP by at least 50% from the preoperative values. At the same time, the risk of an increase in the level of IOP above the target values is about 10% per year, which leads to the fact that after 5 years only in 50% of cases drainage devices function effectively. Therefore, studies of biomaterials, forms and techniques of drainage implantation surgery, new controlled-release antifibrotic drugs can positively affect the long-term effectiveness of glaucoma surgery.Conclusion. The data presented in the literature review allow us to identify the most effective models of drainage devices, their effectiveness, implantation techniques and possible complications

Интраоперационное применение антиметаболитов в хирургии глаукомы

Glaucoma is the main cause of irreversible blindness worldwide, the treatment of which is based on reducing intraocular pressure to tolerant values. Despite the development of medication and laser methods, surgery remains the most effective means of glaucoma treatment, while trabeculectomy remains the golden standard of surgery. However, postoperative scarring remains a critical determinant of long-term bleb survival and IOP control after drainage surgery. Antimetabolites, such as mitomycin C and 5-fluorouracil, have been used to increase the survival time of filtration surgeries by preventing bleb fibrosis and scarring. Mitomycin C is activated via enzymatic reduction into metabolites that inhibit cell replication by inhibiting DNA synthesis, RNA transcription, and protein synthesis. In tissue culture, MMC induces apoptosis of tenon fibroblasts. MMC blocks cell division, which in turn inhibits fibroblast proliferation and enhances bleb formation and function.This review includes a literature analysis on the use of antimetabolites in glaucoma surgery. Based on the data and literary sources of recent years, a general understanding of the mechanism of action of MMS and the need for its use in the course of AGO, but exclusively with low doses and short exposure times, has been achieved, which will reduce the frequency of complications associated with excessive filtration, but at the same time prevent the development of excessive scarring.Глаукома является основной причиной необратимой слепоты во всем мире, лечение которой основано на снижении внутриглазного давления (ВГД) до толерантных значений. Несмотря на развитие медикаментозных и лазерных методов, хирургическое лечение является наиболее эффективным, при этом золотым стандартом хирургии остается трабекулэктомия. Избыточное рубцевание в зоне операции является критическим фактором в долгосрочном функционировании фильтрационной зоны и поддержании приемлемого уровня ВГД. Антиметаболиты, такие как митомицин С (ММС) и 5-фторурацил, используются для увеличения сроков эффективной работы фильтрационных операций за счет предотвращения фиброза и рубцевания. ММС активируется путем ферментативного восстановления в метаболиты, которые ингибируют репликацию клеток, ингибируя синтез дезоксирибонуклеиновой кислоты (ДНК), транскрипцию рибонуклеиновой кислоты (РНК) и синтез белка. В культуре ткани препарат индуцирует апоптоз фибробластов теноновой капсулы. Применение митомицина С в ходе операции способствует ингибированию пролиферации фибробластов, тем самым сохраняет активность сформированных путей оттока.Представленный обзор включает анализ литературных данных применения антиметаболитов в хирургии глаукомы. На основании публикаций последних лет достигнуто понимание механизма действия ММС и необходимость его использования в ходе антиглаукомных операций, однако практически все доступные источники рекомендуют низкие дозы и короткое время воздействия, что уменьшит частоту осложнений, связанных с избыточной фильтрацией и токсическим действием самого препарата, но при этом предотвратит развитие избыточного рубцевания

Electronic properties and phase transitions in low-dimensional semiconductors

We present the first review of the current state of the literature on electronic properties and phase transitions in TlX and TlMX2 (M = Ga, In; X = Se, S, Te) compounds. These chalcogenides belong to a family of the low-dimensional semiconductors possessing chain or layered structure. They are of significant interest because of their highly anisotropic properties, semi- and photoconductivity, non-linear effects in their I-V characteristics (including a region of negative differential resistance), switching and memory effects, second harmonic optical generation, relaxor behavior and potential applications for optoelectronic devices. We review the crystal structure of TlX and TlMX2 compounds, their transport properties under ambient conditions, experimental and theoretical studies of the electronic structure, transport properties and semiconductor-metal phase transitions under high pressure, and sequences of temperature-induced structural phase transitions with intermediate incommensurate states. Electronic nature of the ferroelectric phase transitions in the above-mentioned compounds, as well as relaxor behavior, nanodomains and possible occurrence of quantum dots in doped and irradiated crystals is discussed.Comment: 70 pages, 38 figure

Overview of the TCV tokamak experimental programme

The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with \u27small\u27 (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations

The afterglows of Swift-era gamma-ray bursts. I. Comparing pre-Swift and Swift-era long/soft (type II) GRB optical afterglows

We have gathered optical photometry data from the literature on a large sample of Swift-era gamma-ray burst (GRB) afterglows including GRBs up to 2009 September, for a total of 76 GRBs, and present an additional three pre-Swift GRBs not included in an earlier sample. Furthermore, we publish 840 additional new photometry data points on a total of 42 GRB afterglows, including large data sets for GRBs 050319, 050408, 050802, 050820A, 050922C, 060418, 080413A, and 080810. We analyzed the light curves of all GRBs in the sample and derived spectral energy distributions for the sample with the best data quality, allowing us to estimate the host-galaxy extinction. We transformed the afterglow light curves into an extinction-corrected z = 1 system and compared their luminosities with a sample of pre-Swift afterglows. The results of a former study, which showed that GRB afterglows clustered and exhibited a bimodal distribution in luminosity space, are weakened by the larger sample. We found that the luminosity distribution of the two afterglow samples (Swift-era and pre-Swift) is very similar, and that a subsample for which we were not able to estimate the extinction, which is fainter than the main sample, can be explained by assuming a moderate amount of line-of-sight host extinction. We derived bolometric isotropic energies for all GRBs in our sample, and found only a tentative correlation between the prompt energy release and the optical afterglow luminosity at 1 day after the GRB in the z = 1 system. A comparative study of the optical luminosities of GRB afterglows with echelle spectra (which show a high number of foreground absorbing systems) and those without, reveals no indication that the former are statistically significantly more luminous. Furthermore, we propose the existence of an upper ceiling on afterglow luminosities and study the luminosity distribution at early times, which was not accessible before the advent of the Swift satellite. Most GRBs feature afterglows that are dominated by the forward shock from early times on. Finally, we present the first indications of a class of long GRBs, which form a bridge between the typical highluminosity, high-redshift events and nearby low-luminosity events (which are also associated with spectroscopic supernovae) in terms of energetics and observed redshift distribution, indicating a continuous distribution overall. © 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A