The "Horizon-T" Experiment: Extensive Air Showers Detection

Horizon-T is an innovative detector system constructed to study Extensive Air Showers (EAS) in the energy range above 10^16 eV coming from a wide range of zenith angles (0 - 85 degrees). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. It consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector subsystem to view the Vavilov-Cerenkov light from the EAS. The time resolution of charged particles and Vavilov-Cerenkov light photons passage of the detector system is a few ns. This level of resolution allows conducting research of atmospheric development of individual EAS.Comment: Initial technical note for Horizon-T experiment, updated with recent detector upgrades, 11/2016. Updated 12/2017 with minor edits. Large upgrade will be in another articl

Предикторы неблагоприятных клинических исходов эндоваскулярной тромбэктомии в острейшем периоде ишемического инсульта

Introduction. Stroke is recognized as one of the most significant global socio-economic issues. Endovascular interventions, including mechanical thrombectomy of cerebral arteries, have been increasingly performed during the past decade to restore impaired cerebral blood flow in the first hours from the onset of the disease. However, it has been observed that the technical success of the procedure does not always imply an improvement in the clinical condition of a patient.Materials and methods. The study retrospectively analyzes the outcomes of interventions in 86 acute ischemic stroke patients in order to identify factors that can exert an adverse effect on the first hours of the disease and potentially worsen the results of reperfusion therapy. The study involves patients aged 35–85 years (mean age 66.82±1.52 years), predominantly males (57 males versus 29 females). 42 patients (49%) suffered atrial fibrillation, of which 28 (66.7%) had permanent, 11 (26.2%) — paroxysmal, 3 — persistent atrial fibrillation (7.1%), and 27 (31.4%) suffered diabetes mellitus.Results and discussion. Based on the study, factors affecting outcome and one-year long-term results were identified. The predictors included severity of neurological deficit according to Rankin and NIH Stroke scales, time between symptom onset and reperfusion, TICI thrombectomy score, age, diabetes mellitus, and haemorrhagic transformation after thrombectomy.Conclusion. In order to ensure better outcomes, medical specialists should develop an efficient patient routing, pay special attention to the initial severity of neurological deficit, time from the onset of the disease, age of patients, concomitant diabetes mellitus, development of hemorrhagic transformation after endovascular thrombectomy, and, which is particularly important, to the combination of adverse factors.Введение. В мире инсульт является одной из самых значимых социально-экономических проблем. В последнее десятилетие все чаще для восстановления нарушенного мозгового кровотока в первые часы с момента заболевания применяются эндоваскулярные вмешательства, в том числе механическая тромбэктомия из церебральных артерий. Однако было замечено, что технический успех операции не всегда сопровождался улучшением клинического состояния пациентов.Материалы и методы. В исследовании ретроспективно были проанализированы результаты вмешательств у 86 пациентов с острым ишемическим инсультом с целью выявления факторов, способных оказывать негативное влияние на течение заболевания в первые часы и потенциально ухудшающих результаты реперфузионной терапии. Пациенты были в возрасте от 35 до 85 лет (средний возраст — 66,82 ± 1,52 года), преобладали мужчины (57 против 29). У 42 пациентов (49 %) имелась фибрилляция предсердий, из них у 28 (66,7 %) — постоянная форма, у 11 (26,2 %) — пароксизмальная форма, у 3 — персистирующая форма (7,1 %). У 27 (31,4 %) — сахарный диабет.Результаты и обсуждение. По итогам исследования выявлены факторы, влияющие на исход и отдаленные годичные результаты. К ним отнесли тяжесть неврологического дефицита по шкале Рэнкин и NIHSS, время от начала симптоматики до реперфузии, результат тромбэктомии по шкале TICI, возраст, наличие сахарного диабета, геморрагическая трансформация после тромбэктомии.Заключение. Для достижения лучших результатов необходима разработка оптимальной схемы маршрутизации пациентов, при которой следует обращать особое внимание на исходную тяжесть неврологического дефицита, время от начала заболевания, возраст больных, сопутствующий сахарный диабет, развитие геморрагической трансформации после проведения эндоваскулярной тромбэктомии и особенно на сочетание неблагоприятных факторов

Research of characteristics of multi-frequency laser radiation in case of mode retuning

The changes of characteristics of radiation of the multifrequency helium–neon laser under retuning of its resonator is experimentally investigated. The quantitative results showing the range of occurrence of dispersion properties of the active medium and behaviour of a combination beating signal for the purpose of their further use for laser stabilization are obtained

Method for compensation of atmospheric nonstationarity in heterodyne interferometer measurements

A laser heterodyne system for recording of small shifts and vibrations of remote objects is presented. The use of additional compensation interferometer makes it possible to compensate the influence of environmental fluctuations on the measurement results. The registration results of seismic vibrations for various setup configuration are shown. The experiments indicate the reducing of perturbations of the air refractive index and laser frequency instability by implementing both hardware and software compensation of instabilities

Research of characteristics of multi-frequency laser radiation in case of mode retuning

The changes of characteristics of radiation of the multifrequency helium–neon laser under retuning of its resonator is experimentally investigated. The quantitative results showing the range of occurrence of dispersion properties of the active medium and behaviour of a combination beating signal for the purpose of their further use for laser stabilization are obtained

Relation between Morphology and Porous Structure of SAPO-11 Molecular Sieves and Chemical and Phase Composition of Silicoaluminophosphate Gels

The formation of silicoaluminophosphate gels using boehmite, Al isopropoxide, and di-n-propylamine as a template of silicoaluminophosphate gels as well as their subsequent crystallization into SAPO-11 molecular sieves was studied in detail using X-ray fluorescence spectroscopy (XRF), powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption–desorption methods. The effect of the chemical and phase composition of silicoaluminophosphate gels on the physicochemical properties of SAPO-11 molecular sieves was shown. The secondary structural units that the AEL lattice is composed of were found to be formed at the initial stage of preparation involving aluminum isopropoxide. Several approaches to control their morphology and secondary porous structure are also proposed