230 research outputs found
Effects of a Unilateral Injection of Botulinum Neurotoxin Subtype-A in the Subthalamic Nucleus of a Parkinsonian Rat Model
Dopaminergic degeneration in Parkinson’s disease (PD) leads to altered functional activity within the basal ganglia (BG) circuitry, including hyperactivity of the subthalamic nucleus (STN). Treatments restoring the BG functional circuitry often result in improvements in parkinsonian symptoms in patients and animal models. A recent study from our laboratory identified that infusing botulinum toxin (BoNT-A) into the internal globus pallidus provided a transient restoration of motor asymmetry and goal-directed locomotion in a rat model of PD. We hypothesized that infusions of BoNT-A into the STN in a parkinsonian rat model will improve motor asymmetry and locomotor abnormalities. Infusions of BoNT-A into the ipsilateral STN in unilaterally 6-hydroxydopamine lesioned rats assessed in the apomorphine rotation task, rotarod, or CatWalk apparatus revealed a dose-dependent amelioration of pathological rotations, while failing to affect spontaneous locomotion. The present results suggest that spontaneous locomotion may not dependent on the integrity of the BG functional circuitry
Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around <10-Day-Old Type II Supernovae
Supernovae (SNe) embedded in dense circumstellar material (CSM) may show prominent emission lines in their early-time spectra (≤10 days after the explosion), owing to recombination of the CSM ionized by the shock-breakout flash. From such spectra ("flash spectroscopy"), we can measure various physical properties of the CSM, as well as the mass-loss rate of the progenitor during the year prior to its explosion. Searching through the Palomar Transient Factory (PTF and iPTF) SN spectroscopy databases from 2009 through 2014, we found 12 SNe II showing flash-ionized (FI) signatures in their first spectra. All are younger than 10 days. These events constitute 14% of all 84 SNe in our sample having a spectrum within 10 days from explosion, and 18% of SNe II observed at ages <5 days, thereby setting lower limits on the fraction of FI events. We classified as "blue/featureless" (BF) those events having a first spectrum that is similar to that of a blackbody, without any emission or absorption signatures. It is possible that some BF events had FI signatures at an earlier phase than observed, or that they lack dense CSM around the progenitor. Within 2 days after explosion, 8 out of 11 SNe in our sample are either BF events or show FI signatures. Interestingly, we found that 19 out of 21 SNe brighter than an absolute magnitude M_R = −18.2 belong to the FI or BF groups, and that all FI events peaked above M_R = −17.6 mag, significantly brighter than average SNe II
Феномен Петровского (к 75-летнему юбилею)
Brief scientific biography of a well-known scientist, a leader in the field of experimental study of crystallization processes with usage the holographic method for quantitative analysis of temperature-convective inhomogeneities in the «growth-criticalstone» system, a specialist in crystallographic-mineralogical study of diamonds and their accessory minerals, a successful researcher of modern mineral formation at Kamchatka volcanoes, one of the founders of the «literally from scratch» enterprise for the production of industrial diamonds.Краткая научная биография известного ученого – лидера в области экспериментального изучения процессов кристаллизации с использованием голографического метода для количественного анализа температурно-конвективных неоднородностей в системе «кристалл–среда», специалиста по кристаллографоминералогическому изучению алмазов и их минералов-спутников, успешного исследователя современного минералообразования на камчатских вулканах, одного из создателей «буквально на пустом месте» высокотехнологичного предприятия по производству технических алмазов
Универсальный гироинклинометр на базе единственного одноосного датчика угловой скорости
Introduction. Currently, the versatility and reliability of gyroscopic inclinometers (GI), more than accuracy, determine their configuration and design. Imperative conditions for versatility include a diameter of 42…44.5 mm and a combination of point and continuous survey modes. Reliability is primarily determined by the robustness of the main elements. The fundamental parameter is adaptability to the trajectory, in other words, equal accuracy in the operating range of zenith angles, which determines the choice of orientation of the angular velocity sensors (ARS) with incomplete (< 3) number of their axis. Presently, biaxial dynamically tuned gyroscopes (DNG) are widely used due to their dimension and accuracy criteria; however, their elastic suspension gradually degrades as a result of frequent sidetracking operations (from previously drilled ones) accompanied by high-intensity impacts.Aim. To develop an inexpensive versatile GI that maintains a balance between shock resistance and accuracy (com[1]parable to fiber-optic ARS) based on a single-axis vibrating ring gyroscope (VRG) with an induction-type resonator made using MEMS technology.Materials and methods. The method of multi-position compassing with a single uniaxial ARS was implemented by transition from simultaneous biaxial measurements to uniaxial measurements in five successive positions of the frame (through 90°) along the toolface angle. Experimental data on the drifts of the selected VRG allow statistical methods to be used to construct an Allan-variance plot to confirm that the proposed method does not increase the total compassing time compared to the basic one. The continuous mode of such a GI, studied by solving differential equations, requires holding the input axis of the ARS near the apsidal plane using the same rotating frame.Results. The obtained ratios confirm that the performance characteristics of a GI with a uniaxial ARS approximately correspond to the conventional biaxial scheme. These conclusions were also confirmed by the mathematical modeling of a survey of a typical oil and gas well.Conclusion. The described GI containing a single ARS with indirect stabilization of the input axis is the result of a consistent development of the approach to the use of incomplete informationВведение. Сегодня универсальность и надежность гироскопических инклинометров (ГИ) более, чем точность, определяют их комплектацию и конструктивный облик. Императивные условия универсальности: диаметр 42...44.5 мм и совмещение функций съемки точечной и непрерывной; а безотказность определяется, прежде всего, робастностью основных элементов. Принципиальна "адаптивность" к траектории – "равноточность" в рабочем диапазоне зенитных углов, определяющем выбор ориентации датчиков угловой скорости (ДУС) при их неполном (< 3) числе. По совокупности критериев габаритов и точности сегодня преимущественно применяются двухосные динамически настраиваемые гироскопы, но их упругий подвес при частых операциях "зарезки боковых стволов" (из ранее пробуренных), сопровождаемых ударами большой интенсивности, постепенно деградирует.Цель работы. Создать недорогой универсальный ГИ, сохраняющий компромисс ударостойкости и точности (сопоставимой с волоконно-оптическими ДУС), на базе одноосного кольцевого вибрационного гироскопа (КВГ) с резонатором индукционного типа, выполненным по MEMS-технологии.Материалы и методы. Метод многопозиционного компасирования при единственном одноосном ДУС реализуется переходом от одновременных двухосных измерений к одноосным – в пяти последовательных (через 90°) положениях рамки по углу отклонителя. Экспериментальные материалы о дрейфах выбранного КВГ позволяют статистическими методами построить вариацию Аллана, которая подтверждает, что предложенная методика по сравнению с базовой не увеличивает общего времени компасирования. Непрерывный режим такого ГИ, исследованный методами решения дифференциальных уравнений, требует удержания входной оси ДУС около апсидальной плоскости с помощью той же поворотной рамки.Результаты. Полученные соотношения подтверждают: тактико-технические характеристики ГИ с одноосным ДУС примерно соответствуют традиционной двухосной схеме. К тем же выводам приводят результаты математического моделирования съемки типового нефтегазового ствола.Заключение. Описаный ГИ, содержащий единственный ДУС с косвенной стабилизацией входной оси, – итог последовательного развития подхода к использованию неполной информаци
STATISTICAL MODEL OF AERODYNAMIC IMPACT ON THE LARGE-SPAN COVERAGE
The aim of the study was to study the possibility of using the Dirichlet distribution as a statistical model of the process of dynamic interaction of large-span structures with aerodynamic load. As an object of research, a model of a hangar building was chosen for the maintenance of two AirbusA-380 aircraft at a scale of 1: 500 blown in a wind tunnel at five directions of wind flow at angles of 0 °, 30 °, 45 °, 60 °, 90 ° to the front of the structure ... It is shown that the statistical model of the Dirichlet distribution has sufficient flexibility and realism and compares favorably with the models built on the basis of the normal distribution, beta distribution, gamma distribution and Poisson distribution when describing the processes of intense dynamic interaction of wind load with structural elements. The problem of finding an integral assessment of the state of the processes of interaction of the wind load with the hangar building for the maintenance of two aircraft was reduced to calculating the self-organization parameter of the distribution over the surface of the building model of the aerodynamic coefficients, which was taken as the ratio of the total weighted amount of the Dirichlet models detected in the analyzed numerical series of the registered signal i-th dimension with negative external entropy to the total weighted number of Dirichlet models with positive external entropy.
The study showed that the dimensionless informational and statistical indicator of self-organization makes it possible from a unified standpoint to assess the states that differ from each other in terms of external signs, the processes of interaction and their dynamics. The integral indicator can be used to rank the efficiency of operating systems and can be useful in assessing the state of the processes of dynamic interaction of the operating pressure and objects and structures of various shapes and purposes
Analytic descriptions for transitional nuclei near the critical point
Exact solutions of the Bohr Hamiltonian with a five-dimensional square well
potential, in isolation or coupled to a fermion by the five-dimensional
spin-orbit interaction, are considered as examples of a new class of dynamical
symmetry or Bose-Fermi dynamical symmetry. The solutions provide baselines for
experimental studies of even-even [E(5)] and odd-mass [E(5|4)] nuclei near the
critical point of the spherical to deformed gamma-unstable phase transition.Comment: LaTeX (elsart), 53 pages; typographical correction to (3.15
Properties of odd nuclei and the impact of time-odd mean fields: A systematic Skyrme-Hartree-Fock analysis
We present a systematic analysis of the description of odd nuclei by the
Skyrme-Hartree-Fock approach augmented with pairing in BCS approximation and
blocking of the odd nucleon. Current and spin densities in the Skyrme
functional produce time-odd mean fields (TOMF) for odd nuclei. Their effect on
basic properties (binding energies, odd-even staggering, separation energies
and spectra) is investigated for the three Skyrme parameterizations SkI3, SLy6,
and SV-bas. About 1300 spherical and axially-deformed odd nuclei with 16 < Z <
92 are considered. The calculations demonstrate that the TOMF effect is
generally small, although not fully negligible. The influence of the Skyrme
parameterization and the consistency of the calculations are much more
important. With a proper choice of the parameterization, a good description of
binding energies and their differences is obtained, comparable to that for even
nuclei. The description of low-energy excitation spectra of odd nuclei is of
varying quality depending on the nucleus
Multi-quasiparticle gamma-band structure in neutron-deficient Ce and Nd isotopes
The newly developed multi-quasiparticle triaxial projected shell-model
approach is employed to study the high-spin band structures in
neutron-deficient even-even Ce- and Nd-isotopes. It is observed that
gamma-bands are built on each intrinsic configuration of the triaxial
mean-field deformation. Due to the fact that a triaxial configuration is a
superposition of several K-states, the projection from these states results in
several low-lying bands originating from the same intrinsic configuration. This
generalizes the well-known concept of the surface gamma-oscillation in deformed
nuclei based on the ground-state to gamma-bands built on multi-quasiparticle
configurations. This new feature provides an alternative explanation on the
observation of two I=10 aligning states in 134Ce and both exhibiting a neutron
character.Comment: 15 pages, 9 figures, accepted by Nucl. Phys.
Усть-ишимская кость: минералогогеохимические свойства как источник палеонтологической, палеоантропологической и палеоэкологической информации
Ust-Ishim man was the representative of one of the ancestral groups of the Homo sapiens, Neanderthals and Denisovans. The first results of a comprehensive mineralogical and geochemical study of fossil bones using a wide range of physical, chemical and physico-chemical methods: thermal analysis, optical microscopy, scanning electron microscopy, atomic-force microscopy, nitrogen capillary condensation method, X-ray fluorescence analysis, ISP-MS, gas chromatography method, amino acid chromatography analysis’s, X-ray microprobe method, X-ray diffraction method, Raman and infrared spectroscopy, isotope spectrometry are presented in this article. The studied fragment of the skeleton is of higher preservation rate than the common bone detritus of this age and even the fossils of younger Pleistocene animals that allowed determining almost all its primary properties. The unique preservation presumably was provided by the favorable environment and a special way the Ust-Ishim man originally was buried. Results of study of the chemical and mineral composition of the bone fossils allowed a reconstruction of the Ust-Ishim man life history.Впервые проведено минералого-геохимическое исследование ископаемой кости с использованием широкого комплекса физических, физико-химических и химических методов: термического анализа, оптической, сканирующей электронной, сканирующей зондовой микроскопии, капиллярной конденсации азота, рентгенфлуоресцентного анализа, ИСП-МС, газовой хроматографии, рентгеноспектрального микрозондового анализа, рентгеновской дифракции, инфракрасной и КР спектроскопии, изотопной спектрометрии. Изученный нами фрагмент кости устьишимского человека на фоне костного детрита современных ему и даже значительно более молодых плейстоценовых промысловых животных характеризуется аномально высокой степенью сохранности практически по всем своим свойствам. Феномен столь аномальной сохранности можно объяснить тем, что устьишимский человек первоначально был захоронен либо в особом месте, либо особенным способом
- …