Storage of Correlated Patterns in Standard and Bistable Purkinje Cell Models

The cerebellum has long been considered to undergo supervised learning, with climbing fibers acting as a ‘teaching’ or ‘error’ signal. Purkinje cells (PCs), the sole output of the cerebellar cortex, have been considered as analogs of perceptrons storing input/output associations. In support of this hypothesis, a recent study found that the distribution of synaptic weights of a perceptron at maximal capacity is in striking agreement with experimental data in adult rats. However, the calculation was performed using random uncorrelated inputs and outputs. This is a clearly unrealistic assumption since sensory inputs and motor outputs carry a substantial degree of temporal correlations. In this paper, we consider a binary output neuron with a large number of inputs, which is required to store associations between temporally correlated sequences of binary inputs and outputs, modelled as Markov chains. Storage capacity is found to increase with both input and output correlations, and diverges in the limit where both go to unity. We also investigate the capacity of a bistable output unit, since PCs have been shown to be bistable in some experimental conditions. Bistability is shown to enhance storage capacity whenever the output correlation is stronger than the input correlation. Distribution of synaptic weights at maximal capacity is shown to be independent on correlations, and is also unaffected by the presence of bistability

Комплексная лучевая диагностика отграниченного местного перитонита

The purpose of the study. To clarify the possibilities of using radiation research methods in the framework of complex diagnostics of local peritonitis for timely recognition and treatment of intra-abdominal abscesses and infiltrates.Materials and methods. The analysis of the results of a complex radiation examination in 61 patients with local peritonitis of various etiologies who were treated at the N.V. Sklifosovsky Research Institute for Emergency Medicine was carried out. The complex of radiation diagnostics included ultrasound and X-ray examinations, computed tomography (CT). The studies were performed both initially at admission and in dynamics.Results. The diagnostic algorithm for local peritonitis is analyzed, three stages are identified with the determination of the method of choice on each of them. Ultrasound and X-ray examination methods are mainly used at the stage of primary diagnostics and for dynamic control. CT allows you to clarify the type, localization and volume of inflammatory changes, their relationship with the surrounding organs and structures. When analyzing the results of radiation diagnostics, it was determined the need to identify and evaluate the main signs of local peritonitis, both direct: the presence of voluminous formation of inflammatory genesis (infiltrate and/or abscess); and indirect: changes in the source organ of peritonitis; changes in structures adjacent to the infiltrate /abscess; the presence of reactive effusion into the thoracic and abdominal cavities.Conclusion. Comprehensive radiation diagnostics for local peritonitis makes it possible to obtain complete information about the nature of both inflammatory changes in local peritonitis and the causes of them. The obtained data of complex diagnostics help the surgeon to choose a rational treatment strategy for these patients, including minimally invasive. Diagnostic monitoring allows you to evaluate the effectiveness of treatment and carry out timely correction of tactics.Цель исследования: уточнить возможности применения лучевых методов исследования в рамках комплексной диагностики отграниченного местного перитонита для своевременного распознавания и лечения внутрибрюшных абсцессов и инфильтратов.Материал и методы. Проведен анализ результатов комплексного лучевого исследования у 61 пациента с отграниченным местным перитонитом различной этиологии, находившихся на лечении в НИИ СП им. Н.В. Склифосовского. Комплекс лучевой диагностики включал ультразвуковое и рентгенологическое исследования, компьютерную томографию. Исследования были выполнены как первично при поступлении, так и в динамике.Результаты. Проанализирован диагностический алгоритм при отграниченном местном перитоните, выделены три этапа с определением метода выбора на каждом из них. Ультразвуковой и рентгеновский методы исследования используются преимущественно на этапе первичной диагностики и для динамического контроля. Компьютерная томография позволяет уточнить вид, локализацию и объем воспалительных изменений, их взаимоотношения с окружающими органами и структурами. При анализе результатов лучевой диагностики была определена необходимость в выявлении и оценке основных признаков отграниченного местного перитонита, как прямых: наличие объемного образования воспалительного генеза (инфильтрат и/или абсцесс), так и косвенных: изменения органа – источника перитонита; изменения прилежащих к инфильтрату/абсцессу структур;  наличие реактивного выпота в грудную и брюшную полости.Заключение. Комплексная лучевая диагностика при отграниченном местном перитоните дает возможность получить полную информацию о характере как воспалительных изменений в брюшной полости, так и причин, их вызывающих. Полученные данные комплексной диагностики помогают хирургу выбрать рациональную тактику лечения этих больных, в том числе минимально инвазивную. Диагностический мониторинг позволяет оценить эффективность лечения и проводить своевременную коррекцию тактики

Thermally activated exciton dissociation and recombination control the carrier dynamics in organometal halide perovskite.

Solar cells based on organometal halide perovskites have seen rapidly increasing efficiencies, now exceeding 15%. Despite this progress, there is still limited knowledge on the fundamental photophysics. Here we use microwave photoconductance and photoluminescence measurements to investigate the temperature dependence of the carrier generation, mobility, and recombination in (CH3NH3)PbI3. At temperatures maintaining the tetragonal crystal phase of the perovskite, we find an exciton binding energy of about 32 meV, leading to a temperature-dependent yield of highly mobile (6.2 cm(2)/(V s) at 300 K) charge carriers. At higher laser intensities, second-order recombination with a rate constant of gamma = 13 x 10(-10) cm(3) s(-1) becomes apparent. Reducing the temperature results in increasing charge carrier mobilities following a T-1.6 dependence, which we attribute to a reduction in phonon scattering (Sigma mu = 16 cm(2)/(V s) at 165 K). Despite the fact that Sigma mu increases, gamma diminishes with a factor six, implying that charge recombination in (CH3NH3)PbI3 is temperature activated. The results underline the importance of the perovskite crystal structure, the exciton binding energy, and the activation energy for recombination as key factors in optimizing new perovskite materials