2,668 research outputs found
On weak coupling expansion in models with unbroken symmetry
An investigation of the weak coupling region of 2D SU(N) spin models is
presented. An expansion of the free energy and correlation functions at low
temperatures is performed in the link formulation with periodic boundary
conditions (BC). The resulting asymptotics is shown to be nonuniform in the
volume for the free energy.Comment: LATTICE98(spin), 3 page
On weak convergence of functionals on smooth random functions
The numbers of level crossings and extremes for random processes and fields play an important role in reliability theory and many engineering applications. In many cases for Gaussian processes the Poisson approximation for their asymptotic distributions is used.
This paper extends an approach proposed in Rusakov and Seleznjev (1988) for smooth random processes on a finite interval. It turns out that a number of functionals (including some integervalued ones) become continuous on the space of smooth functions and weak convergence results for the sequences of such continuous functionals
are applicable. Examples of such functionals for smooth random processes on infinite intervals and for random fields are studied
Optical monitoring of glutamate release at multiple synapses in situ detects changes following LTP induction
Information processing and memory formation in the brain relies on release of the main excitatory neurotransmitter glutamate from presynaptic axonal specialisations. The classical Hebbian paradigm of synaptic memory, long-term potentiation (LTP) of transmission, has been widely associated with an increase in the postsynaptic receptor current. Whether and to what degree LTP induction also enhances presynaptic glutamate release has been the subject of debate. Here, we took advantage of the recently developed genetically encoded optical sensors of glutamate (iGluSnFR) to monitor its release at CA3-CA1 synapses in acute hippocampal slices, before and after the induction of LTP. We attempted to trace release events at multiple synapses simultaneously, by using two-photon excitation imaging in fast frame-scanning mode. We thus detected a significant increase in the average iGluSnFR signal during potentiation, which lasted for up to 90 min. This increase may reflect an increased amount of released glutamate or, alternatively, reduced glutamate binding to high-affinity glutamate transporters that compete with iGluSnFR
Automation of Analysis of Thermographic Images in Diagnostics of Honeycomb Core Structure States
A method for converting the results of an active thermal imaging control of products made of polymer composite materials, using the Theil-Sen estimator, is described. Approbation of the described translation algorithm operation on a sample made in accordance with the technology of manufacturing the aircraft plane part is carried out
Genetically engineered MAPT 10+16 mutation causes pathophysiological excitability of human iPSC-derived neurons related to 4R tau-induced dementia
Human iPSC lines represent a powerful translational model of tauopathies. We have recently described a pathophysiological phenotype of neuronal excitability of human cells derived from the patients with familial frontotemporal dementia and parkinsonism (FTDP-17) caused by the MAPT 10+16 splice-site mutation. This mutation leads to the increased splicing of 4R tau isoforms. However, the role of different isoforms of tau protein in initiating neuronal dementia-related dysfunction, and the causality between the MAPT 10+16 mutation and altered neuronal activity have remained unclear. Here, we employed genetically engineered cells, in which the IVS10+16 mutation was introduced into healthy donor iPSCs to increase the expression of 4R tau isoform in exon 10, aiming to explore key physiological traits of iPSC-derived MAPT IVS10+16 neurons using patch-clamp electrophysiology and multiphoton fluorescent imaging techniques. We found that during late in vitro neurogenesis (from ~180 to 230 days) iPSC-derived cortical neurons of the control group (parental wild-type tau) exhibited membrane properties compatible with "mature" neurons. In contrast, MAPT IVS10+16 neurons displayed impaired excitability, as reflected by a depolarized resting membrane potential, an increased input resistance, and reduced voltage-gated Na+- and K+-channel-mediated currents. The mutation changed the channel properties of fast-inactivating Nav and decreased the Nav1.6 protein level. MAPT IVS10+16 neurons exhibited reduced firing accompanied by a changed action potential waveform and severely disturbed intracellular Ca2+ dynamics, both in the soma and dendrites, upon neuronal depolarization. These results unveil a causal link between the MAPT 10+16 mutation, hence overproduction of 4R tau, and a dysfunction of human cells, identifying a biophysical basis of changed neuronal activity in 4R tau-triggered dementia. Our study lends further support to using iPSC lines as a suitable platform for modelling tau-induced human neuropathology in vitro
Release probability increases towards distal dendrites boosting high-frequency signal transfer in the rodent hippocampus
Dendritic integration of synaptic inputs involves their increased electrotonic attenuation at distal dendrites, which can be counterbalanced by the increased synaptic receptor density. However, during network activity the influence of individual synapses depends on their release fidelity, the dendritic distribution of which remains poorly understood. Here, we employed classical optical quantal analyses and a genetically encoded optical glutamate sensor in acute hippocampal slices of rats and mice to monitor release at CA3-CA1 synapses. We find that their release probability increases with greater distances from the soma. Similar-fidelity synapses tend to group together whereas release probability shows no trends regarding the branch ends. Simulations with a realistic CA1 pyramidal cell hosting stochastic synapses suggest that the observed trends boost signal transfer fidelity, particularly at higher input frequencies. Because high-frequency bursting has been associated with learning, the release probability pattern we have found may play a key role in memory trace formation
Convergence for step line processes under summation of random indicators and models of market pricing
Functional limit theorems for random step lines and random broken lines defined by sums of iid random variables with replacements are obtained and discussed. Also we obtained functional limit theorems for integrals of such random processes. We use our results to study a number of models of the financial market
Dopamine elevates and lowers astroglial Ca(2+) through distinct pathways depending on local synaptic circuitry
Whilst astrocytes in culture invariably respond to dopamine with cytosolic Ca(2+) rises, the dopamine sensitivity of astroglia in situ and its physiological roles remain unknown. To minimize effects of experimental manipulations on astroglial physiology, here we monitored Ca(2+) in cells connected via gap junctions to astrocytes loaded whole-cell with cytosolic indicators in area CA1 of acute hippocampal slices. Aiming at high sensitivity of [Ca(2+) ] measurements, we also employed life-time imaging of the Ca(2+) indicator Oregon Green BAPTA-1. We found that dopamine triggered a dose-dependent, bidirectional Ca(2+) response in stratum radiatum astroglia, a jagged elevation accompanied and followed by below-baseline decreases. The elevation depended on D1/D2 receptors and engaged intracellular Ca(2+) storage and removal whereas the dopamine-induced [Ca(2+) ] decrease involved D2 receptors only and was sensitive to Ca(2+) channel blockade. In contrast, the stratum lacunosum moleculare astroglia generated higher-threshold dopamine-induced Ca(2+) responses which did not depend on dopamine receptors and were uncoupled from the prominent inhibitory action of dopamine on local perforant path synapses. Our findings thus suggest that a single neurotransmitter-dopamine-could either elevate or decrease astrocyte [Ca(2+) ] depending on the receptors involved, that such actions are specific to the regional neural circuitry and that they may be causally uncoupled from dopamine actions on local synapses. The results also indicate that [Ca(2+) ] elevations commonly detected in astroglia can represent the variety of distinct mechanisms acting on the microscopic scale. GLIA 2016
Soviet Power Plus Rationalization of the Whole Country: Creating the Kingdom of Reason
The correlation between the categories of rational and irrational in the philosophy of the Enlightenment and classical Marxism, which found its embodiment in Russia in the form of Bolshe-vism (Leninism), is studied. The authors identify that rationalism as a kind of "mythology of Reason" arose in the Enlightenment era and reached its apogee in the Great French Revolution and German classical philosophy. Despite the fact that in a number of works of classical Marxism heuristically valuable ideas were put forward to reformulate the problem of the essence and correlation of the categories of ration-al and irrational, rationalism prevailed in the understanding of reality and practices of the first years of the October Revolution. This found expression in the works of V.I. Lenin, in the socio-political and spiritual atmosphere of revolutionary Russia, which had far-reaching consequences for Soviet soci-ety. This phenomenon paved the way for the state-political mythology of Reason and its fetishization, the mystification of science (which, like magic, "can do anything"). These rationalist schematisms pene-trated deeply into all forms of mass consciousness and gave rise to the cult of Reason, on the basis of which all spheres of life of Soviet society were supposed to be transformed. © 2022, RUDN UNiversity. All rights reserved.Russian Foundation for Basic Research, РФФИ, (21-011-43023)arose in the Enlightenment era and reached its apogee in the Great French Revolution and German classical philosophy. Despite the fact that in a number of works of classical Marxism heuristically valuable ideas were put forward to reformulate the problem of the essence and correlation of the categories of ration-al and irrational, rationalism prevailed in the understanding of reality and practices of the first years of the October Revolution. This found expression in the works of V.I. Lenin, in the socio-political and spiritual atmosphere of revolutionary Russia, which had far-reaching consequences for Soviet society. This phenomenon paved the way for the state-political mythology of Reason and its fetishization, the mystification of science (which, like magic, "can do anything"). These rationalist schematisms penetrated deeply into all forms of mass consciousness and gave rise to the cult of Reason, on the basis of which all spheres of life of Soviet society were supposed to be transformed. Keywords: early Soviet period, enlightenment rationalism, mass consciousness Acknowledgements and Funding: The article was prepared with the support of RFBR grant No. 21-011-43023 “The official discourse of the Russian policy of memory of the Soviet past: interpretation strategies, actors, commemorative practices.” For citation: Rusakova, Olga, and Rusakov, Vasiliy. “Soviet Power plus Rationalization of the Whole Country: Creating the Kingdom of Reason.” RUDN Journal of Russian History 21, no. 4 (November 2022): 452–468. https://doi.org/10.22363/2312-8674-2022-21-4-452-46
Принципи організаціїї інтер'єрів центру підготовки пілотів-операторів безпілотної авіації
This paper studies the development of specialized training interiors. We found the principles of functional and spatial organization of interiors center pilot training operators of unmanned aircraft. All rooms are categorized on the basis of the center functionality.Проведены исследования вопросов развития специализированных учебных интерьеров. Выявлены принципы функционально–пространственной организации интерьеров центра подготовки пилотов–операторов беспилотной авиации. Все помещения центра классифицированы по принципу функциональности.В даній статті проведені дослідження питання розвитку спеціалізованих навчальних інтер’єрів. Виявлено принципи функціонально–просторової організації інтер’єрів центру підготовки пілотів–операторів безпілотної авіації. Всі приміщення центру класифіковані за принципом функціональності
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