49 research outputs found
The effective bandwidth problem revisited
The paper studies a single-server queueing system with autonomous service and
priority classes. Arrival and departure processes are governed by marked
point processes. There are buffers corresponding to priority classes,
and upon arrival a unit of the th priority class occupies a place in the
th buffer. Let , denote the quota for the total
th buffer content. The values are assumed to be large, and
queueing systems both with finite and infinite buffers are studied. In the case
of a system with finite buffers, the values characterize buffer
capacities.
The paper discusses a circle of problems related to optimization of
performance measures associated with overflowing the quota of buffer contents
in particular buffers models. Our approach to this problem is new, and the
presentation of our results is simple and clear for real applications.Comment: 29 pages, 11pt, Final version, that will be published as is in
Stochastic Model
Small-angle fragmentation of carbon ions at 0.6 GeV/n: a comparison with models of ion-ion interactions
Momentum distributions of hydrogen and helium isotopes from 12C fragmentation at 3.5° were measured at 0.6 GeV/nucleon in the FRAGM experiment at ITEP TWA heavy ion accelerator. The fragments were selected by correlated time of flight and dE/dx measurements with a magnetic spectrometer with scintillation counters. The main attention was drawn to the high momentum region where the fragment velocity exceeds the velocity of the projectile nucleus. The momentum spectra of fragments span the region of the fragmentation peak as well as the cumulative region. The differential cross sections cover six orders of magnitude. The distributions measured are compared to the predictions of three ion-ion interaction models: BC, QMD and LAQGSM03.03. The kinetic energy spectra of fragments in the projectile rest frame have an exponential shape with two temperatures, being defined by their slope parameters
Pulse Shape Analysis and Identification of Multipoint Events in a Large-Volume Proportional Counter in an Experimental Search for 2K Capture Kr-78
A pulse shape analysis algorithm and a method for suppressing the noise
component of signals from a large copper proportional counter in the experiment
aimed at searching for 2K capture of Kr-78 are described. These signals
correspond to a compound event with different numbers of charge clusters due to
from primary ionization is formed by these signals. A technique for separating
single- and multipoint events and determining the charge in individual clusters
is presented. Using the Daubechies wavelets in multiresolutional signal
analysis, it is possible to increase the sensitivity and the resolution in
extraction of multipoint events in the detector by a factor of 3-4.Comment: 10 pages, 8 figures. submitted to Instruments and Experimental
Techniques; ISSN 0020/441
Phase transitions for suspension flows
This paper is devoted to study thermodynamic formalism for suspension flows
defined over countable alphabets. We are mostly interested in the regularity
properties of the pressure function. We establish conditions for the pressure
function to be real analytic or to exhibit a phase transition. We also
construct an example of a potential for which the pressure has countably many
phase transitions.Comment: Example 5.2 expanded. Typos corrected. Section 6.1 superced the note
"Thermodynamic formalism for the positive geodesic flow on the modular
surface" arXiv:1009.462
Pathological structural conversion of α-synuclein at the mitochondria induces neuronal toxicity
Aggregation of alpha-synuclein (α-Syn) drives Parkinson’s disease (PD), although the initial stages of self-assembly and structural conversion have not been directly observed inside neurons. In this study, we tracked the intracellular conformational states of α-Syn using a single-molecule Förster resonance energy transfer (smFRET) biosensor, and we show here that α-Syn converts from a monomeric state into two distinct oligomeric states in neurons in a concentration-dependent and sequence-specific manner. Three-dimensional FRET-correlative light and electron microscopy (FRET-CLEM) revealed that intracellular seeding events occur preferentially on membrane surfaces, especially at mitochondrial membranes. The mitochondrial lipid cardiolipin triggers rapid oligomerization of A53T α-Syn, and cardiolipin is sequestered within aggregating lipid–protein complexes. Mitochondrial aggregates impair complex I activity and increase mitochondrial reactive oxygen species (ROS) generation, which accelerates the oligomerization of A53T α-Syn and causes permeabilization of mitochondrial membranes and cell death. These processes were also observed in induced pluripotent stem cell (iPSC)–derived neurons harboring A53T mutations from patients with PD. Our study highlights a mechanism of de novo α-Syn oligomerization at mitochondrial membranes and subsequent neuronal toxicity
The Medical Activity and Satisfaction of Population Need in Medical Care
The article considers phenomenon of medical activity as a determinant of population demand for medical services and needs in medical care. The medical activity is determined as both a criterion of formation of health of patients by force of active using medical care and a criterion of efficiency of functioning of physicians in satisfaction of needs of patients in medical care. The results are presented related to phenomenon of medical activity using methodology of analysis of opinions of patients and level of medical care appealability of population. Medical activity of population and level of satisfaction of demand and needs in medical services is to be considered as an evidence of commitment of population to treatment and prevention. The investigation of these issues acquires particular specificity in conditions of health care system of large municipal agglomeration with developed network of medical organizations of budget insurance, departmental and private forms of property. In these conditions, patients and population are provided with various possibilities of choosing different forms and types of satisfaction of need in medical care independently of cause and motive of using it that is an advantage for implementing medical activity
ОСОБЕННОСТИ ХАРАКТЕРА СЕЙСМИЧНОСТИ ЦЕНТРАЛЬНОЙ И ВОСТОЧНОЙ ЧАСТЕЙ ПЕРСИДСКОГО ЗАЛИВА
The article presents some of the main characteristics of the seismicity regime of the central and eastern parts of the Persian Gulf and its coast. Data on the number and spatial position of seismic events, their energy characteristics (magnitudes) and the depth of the source zones were analyzed. The distribution of the number of seismic events over time reveals a quasi-periodic structure with a half-period of about 5-6 years. It should be noted that with an increase or a significant decrease in the number of earthquakes, the spatial position of the zones of their epicenters remains unchanged. The position of the hypocenters of the earthquakes under consideration covers a wide range of depths from shallow (2-10 km) to deeper (20-30 km). There is a clear General trend towards a decrease in the average depth level of focal zones during the period under review, against which time intervals are distinguished with a relatively large average for the year and a relatively small level of immersion of hypocenters. The analysis of temporal variations of seismicity of the North-Eastern part of the Persian Gulf basin showed high activity of seismic processes.В статье приводятся некоторые основные характеристики режима сейсмичности центральной и восточной частей Персидского залива и его побережья. Анализировались данные по количеству и пространственной позиции сейсмических событий, их энергетические характеристики (магнитуды) и глубины очаговых зон. Характер распределения во времени количества сейсмических событий обнаруживает квазипериодическую структуру с полупериодом порядка 5-6 лет. Следует отметить, что при увеличении или при существенном уменьшении количества землетрясений пространственное положение зон расположения их эпицентров остается неизменным. Положение гипоцентров рассматриваемых землетрясений охватывает широкий диапазон глубин - от мелкофокусных (2-10 км) до более глубоких (20-30 км). Отчетливо прослеживается общая тенденция к уменьшению за рассматриваемый период среднего уровня глубин очаговых зон, на фоне которого выделяются временные интервалы с относительно большим в среднем за год и относительно небольшим уровнем погружения гипоцентров. Выполненный анализ временных вариаций сейсмичности северо-восточной части бассейна Персидского залива показал высокую активность сейсмических процессов
ОЦЕНКА СЕЙСМИЧНОСТИ ЦЕНТРАЛЬНОЙ И ВОСТОЧНОЙ ЧАСТЕЙ ПЕРСИДСКОГО ЗАЛИВА И СВЯЗЬ С НЕФТЕГАЗОНОСНОСТЬЮ РЕГИОНА
The main characteristics of the seismic regime of the central and eastern parts of the Persian Gulf and its coast, recorded in the period from 2005 to 2017, are presented. The data were also taken into account throughout the XX century. Attention to the Persian Gulf is determined by two factors: first, there is a seismically active zone associated with fault structures. Secondly, a large number of large hydrocarbon deposits with developed infrastructure are openly and actively developed in this area, the environmental safety of which requires careful consideration of the effects of earthquakes.Представлены основные характеристики режима сейсмичности центральной и восточной частей Персидского залива и его побережья, зафиксированные в период с 2005 по 2017 год. Во внимание принимались также данные и по всему XX веку. Внимание к акватории Персидского залива определяется двумя факторами: во-первых, здесь находится сейсмоактивная зона, связанная с разломными структурами. Во-вторых, в этом районе открыто и активно эксплуатируется большое количество крупных месторождений углеводородного сырья с развитой инфраструктурой, экологическая безопасность которой требует тщательного учета влияния землетрясений
Search for d' in pion inclusive spectra from pp-interactions
We report on our measurement of the inclusive spectrum of positive
pions from the reaction on a internal
target of the ITEP proton synchrotron at with a missing
mass resolution of about . The goal of our experiment was
the search for the hypothetical narrow resonance
( width and a mass of ) with
, called . We do not see any statistically
significant -signal. The upper limit for production
cross-section in -interactions is near at $84\%\ C.L.