Nonlinear axisymmetric liquid currents in spherical annuli

A numerical analysis of non-linear axisymmetric viscous flows in spherical annuli of different gap sizes is presented. Only inner sphere was supposed to rotate at a constant angular velocity. The streamlines, lines of constant angular velocity, kinetic energy spectra, and spectra of velocity components are obtained. A total kinetic energy and torque needed to rotate the inner sphere are calculated as functions of Re for different gap sizes. In small-gap annulus nonuniqueness of steady solutions of Navier-Stokes equations is established and regions of different flow regime existences are found. Numerical solutions in a wide-gap annulus and experimental results are used in conclusions about flow stability in the considered range of Re. The comparison of experimental and numerical results shows close qualitative and quantitative agreement

Statistically-secure ORAM with O~(log⁡2n)\tilde{O}(\log^2 n) Overhead

We demonstrate a simple, statistically secure, ORAM with computational overhead $\tilde{O}(\log^2 n)$; previous ORAM protocols achieve only computational security (under computational assumptions) or require $\tilde{\Omega}(\log^3 n)$ overheard. An additional benefit of our ORAM is its conceptual simplicity, which makes it easy to implement in both software and (commercially available) hardware. Our construction is based on recent ORAM constructions due to Shi, Chan, Stefanov, and Li (Asiacrypt 2011) and Stefanov and Shi (ArXiv 2012), but with some crucial modifications in the algorithm that simplifies the ORAM and enable our analysis. A central component in our analysis is reducing the analysis of our algorithm to a "supermarket" problem; of independent interest (and of importance to our analysis,) we provide an upper bound on the rate of "upset" customers in the "supermarket" problem

Features of diagnosis and treatment of patients with stable coronary artery disease at initially normal arterial pressure

Of 875 patients being under the clinical follow-up at one of the polyclinics in Chelyabinsk, 216 (24.7%) had coronary artery disease (CAD) without arterial hypertension (AH) in past medical history. The authors conducted the comparative study of risk factors and clinical and instrumental features of the disease in 50 patients with isolated coronary artery disease and in 50 patients with coronary artery disease against the background of AH. It was found that the disease onset was more often manifested in the form of angina pectoris in patients with stable coronary artery disease without AG , and in the form of myocardial infarction in patients with CAD and AH. Pathological heredity, obesity, diabetes mellitus were more common in patients with the combination of CAD and AH. Stenosis of over 50% of at least one coronary artery is more often identified in patients with CAD and normal arterial pressure (AP). The full range of beta-blockers and calcium channel blockers may be prescribed to patients with CAD without AH in no more than 20% of cases due to excess drop in AP. The prescription of anti-ischemic drugs trimetazidine OD and ivabradine increased the CAD without AH, where these drugs probably should be referred to the first choice drugs

Network Protocol Performance Bounding Exploiting Properties of Infinite Dimensional Linear Equations ⋆

Abstract. This paper presents a quite versatile and widely applicable performance analysis methodology that has been applied for the study of network resource allocation protocols in the past. It is based on the identification ofrenewal cycles of theoperation of thesystem andthe setting up of recursive equations with respect to quantities-indices defined over the renewal cycles and sessions that appear within. Application of the expectation operator on these equations leads to infinite dimensional systems of linear equations which are shown to posses certain properties leading to rigorous and almost arbitrarily tight bounds on various performance metrics of interest. The special case of a random access protocol is used as an example in order to illustrate the derivation of the recursive equations capturing the protocol dynamics and system inputs. Finally, some other examples of application of the methodology are briefly discussed, illustrating the versatility and powerfulness of the approach. This analysis methodology can be quite useful for understanding the behavior of current complex and large scale networking environments, as well as assessing their scalability, stability and performance.