Variations of auroral hydrogen emission near substorm onset

The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the average energy of precipitating protons and the emission intensity of the hydrogen Balmer line. Two different populations of precipitating protons were observed during an auroral substorm. The first of these is associated with a diffuse hydrogen emission that is usually observed in the evening sector of the auroral oval and located equatorward of the discrete electron arcs associated with substorm onset. The average energy of the protons during this precipitation was ~20–35 keV, and the energy flux was ~3x10<sup>–4</sup>Joule/m<sup>2</sup>s. The second proton population was observed 1–2min after the breakup during 4–5min of the expansion phase of substorm into the zone of bright, discrete auroral structures (N-S arcs). The average energy of the protons in this population was ~60 keV, and the energy flux was ~2.2x10<sup>–3</sup>Joule/m<sup>2</sup>s. The observed spatial structure of hydrogen emission is additional evidence of the higher energy of precipitated protons in the second population, relative to the protons in the diffuse aurora. We believe that the most probable mechanism of precipitation of the second population protons was pitch-angle scattering of particles due to non-adiabatic motion in the region of local dipolarization near the equatorial plane.<p><b>Keywords.</b> Auroral ionosphere; Particle precipitation; Storms and substorm

Optimum design of hydrodynamic thrust bearings with rayleigh's pocket profiles

Optimum design problem for hydrodynamic self-aligning acting thrust bearings was considered. Based on results for rectangular region the problem for sector region was solved. As an objective function, the maximum of pressure integral over the lubricant layer surface was used and five geometrical parameters described Rayleigh's pocket shape were used as optimization variables during optimization procedure. The bearing pressure distribution was determined on the basis of the Navier-Stokes equations using the ANSYS / CFX software. Numerically the optimization problem was solved using three different methods: IOSO, SIMPLEX and pilOPT+AFilter SQP realized in two commercial optimization software IOSO and modeFRONTIER. The aim of this investigation was designing the technologically advanced profiles of thrust bearing sector microgeometry ensuring the maximum load capacity

The Hitting Times with Taboo for a Random Walk on an Integer Lattice

For a symmetric, homogeneous and irreducible random walk on d-dimensional integer lattice Z^d, having zero mean and a finite variance of jumps, we study the passage times (with possible infinite values) determined by the starting point x, the hitting state y and the taboo state z. We find the probability that these passages times are finite and analyze the tails of their cumulative distribution functions. In particular, it turns out that for the random walk on Z^d, except for a simple (nearest neighbor) random walk on Z, the order of the tail decrease is specified by dimension d only. In contrast, for a simple random walk on Z, the asymptotic properties of hitting times with taboo essentially depend on the mutual location of the points x, y and z. These problems originated in our recent study of branching random walk on Z^d with a single source of branching

Small deviations of iterated processes in space of trajectories

We derive logarithmic asymptotics of probabilities of small deviations for iterated processes in the space of trajectories. We find conditions under which these asymptotics coincide with those of processes generating iterated processes. When these conditions fail the asymptotics are quite different

On the infimum attained by a reflected L\'evy process

This paper considers a L\'evy-driven queue (i.e., a L\'evy process reflected at 0), and focuses on the distribution of $M(t)$, that is, the minimal value attained in an interval of length $t$ (where it is assumed that the queue is in stationarity at the beginning of the interval). The first contribution is an explicit characterization of this distribution, in terms of Laplace transforms, for spectrally one-sided L\'evy processes (i.e., either only positive jumps or only negative jumps). The second contribution concerns the asymptotics of \prob{M(T_u)> u} (for different classes of functions $T_u$ and $u$ large); here we have to distinguish between heavy-tailed and light-tailed scenarios

К вопросу о «норме» некоторых лабораторных показателей гомеостаза у людей старше 60 лет

Currently, there are no reference values for many laboratory indicators of homeostasis for gerontological patients, which complicates the objective interpretation of their disorders.Aim of study. Based on a comparison of the reference values of some laboratory indicators of homeostasis of volunteers over 65 and people of working age, we offer their conditional norm for people of gerontological age.Materials and methods. Studies of laboratory indicators of homeostasis were carried out in 25 volunteers aged 60 to 85 years. The comparison group consisted of 50 donors aged 18–59 years. Investigated indicators: lipid peroxidation and antioxidant blood system; factors of endogenous vascular regulation; apoptosis of peripheral blood lymphocytes; blood rheology; endotoxemia, immunology. Statistical analysis of the data was performed using the Statistica 10 software package (StatSoft, Inc., USA); when comparing the indicators, the nonparametric Mann–Whitney U test (abnormal distribution) was used.Results. In elderly and senile people, due to physiological aging, as well as the influence of endogenous and exogenous factors and concomitant diseases, there are significant differences in the reference values of some laboratory parameters from the parameters of the same name for people of working age. В настоящее время отсутствуют референтные значения многих лабораторных показателей гомеостаза для геронтологических больных, что затрудняет объективную трактовку их нарушений.Цель. На основании сравнения референтных значений некоторых лабораторных показателей гомеостаза добровольцев старше 65 лет и лиц трудоспособного возраста предложить их условную норму для лиц геронтологического возраста.Материал и методы. Исследования лабораторных показателей гомеостаза проведены у 25 добровольцев в возрасте от 60 до 85 лет. Группу сравнения составили 50 доноров в возрасте 18–59 лет. Исследовали показатели: перекисного окисления липидов и антиоксидантной системы крови; факторов эндогенной сосудистой регуляции; апоптоза лимфоцитов периферической крови; реологии крови; эндотоксикоза, иммунологии. Статистический анализ данных проводили с помощью пакета программы Statistica 10 (StatSoft, Inc., США), при сравнении показателей пользовались непараметрическим методом Манна–Уитни (U-test, ненормальное распределение).Результаты. У лиц пожилого и старческого возраста в силу физиологического старения, а также влияния эндогенных и экзогенных факторов и сопутствующих заболеваний имеются существенные отличия референтных значений некоторых лабораторных показателей от одноименных параметров лиц трудоспособного возраста.Выводы. 1. У добровольцев геронтологического возраста по сравнению с трудоспособным вязкоэластичность крови при различных скоростях сдвигового потенциала выше от 1,24 до 1,47 раз; индекс агрегации эритроцитов в движении — в 1,29 раза, агрегация тромбоцитов на 9%, малоновый диальдегид — в 2 раза, содержание погибших лимфоцитов — в 1,4 раза, доля лимфоцитов на стадии раннего апоптоза в 2, 6 раза, сумма циркулирующих иммунных комплексов — в 1,9 раза. 2 Показатели активированного частичного тромбопластинового времени, антитромбин, CD 95, больших циркулирующих иммунных комплексов снижены у добровольцев старше 60 лет по сравнению с лицами трудоспособного возраста в 1,36 раза, на 6%, в 1,67 и в 2,6 раза соответственно.

Scaling of avalanche queues in directed dissipative sandpiles

We simulate queues of activity in a directed sandpile automaton in 1+1 dimensions by adding grains at the top row with driving rate $0 < r \leq 1$. The duration of elementary avalanches is exactly described by the distribution $P_1(t) \sim t^{-3/2}\exp{(-1/L_c)}$, limited either by the system size or by dissipation at defects $L_c= \min (L,\xi)$. Recognizing the probability $P_1$ as a distribution of service time of jobs arriving at a server with frequency $r$, the model represents a new example of the $$ server queue in the queue theory. We study numerically and analytically the tail behavior of the distributions of busy periods and energy dissipated in the queue and the probability of an infinite queue as a function of driving rate.Comment: 11 pages, 9 figures; To appear in Phys. Rev.