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Search Results: 1 - 10 of 204744 matches for " Boris P. Komrakov "
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Contact Lie algebras of vector fields on the plane
Boris M. Doubrov,Boris P. Komrakov
Mathematics , 1999, DOI: 10.2140/gt.1999.3.1
Abstract: The paper is devoted to the complete classification of all real Lie algebras of contact vector fields on the first jet space of one-dimensional submanifolds in the plane. This completes Sophus Lie's classification of all possible Lie algebras of contact symmetries for ordinary differential equations. As a main tool we use the abstract theory of filtered and graded Lie algebras. We also describe all differential and integral invariants of new Lie algebras found in the paper and discuss the infinite-dimensional case.
Investigation of Joint Effect of Two Mechanisms of Probe Wave Anomalous Attenuation
N. A. Zabotin,A. G. Bronin,G. A. Zhbankov,G. P. Komrakov,S. M. Grach
Physics , 1998,
Abstract: Two mechanisms of anomalous attenuation of probe waves in the experiments of ionosphere modification are discussed in the paper. The first mechanism is the well-known conversion of ordinary wave into plasma waves due to scattering from random irregularities in the upper-hybrid resonance region. The second mechanism is the multiple scattering. This mechanism is responsible for anomalous attenuation of extraordinary wave have been observed in several experiments. Investigation of joint effect of both mechanisms gives additional possibilities for diagnostics of artificial irregularities.
Anomalous attenuation of extraordinary waves in ionosphere heating experiments
N. A. Zabotin,H. A. Mityakov,G. P. Komrakov,V. L. Frolov,E. N. Sergeev,A. G. Bronin,G. A. Zhbankov
Physics , 2000,
Abstract: The results of experimental and theoretical study of anomalous attenuation of probe extraordinary waves in experiments on modification of ionosphere by powerful HF waves on "Sura" heating facility are presented. The experimental data indicate significant attenuation of extraordinary waves which can be explained as a result of multiple scattering of extraordinary waves on small-scale random irregularities. The possibility of diagnostics of spectrum of artificial irregularities from measurements of anomalous attenuation of extraordinary waves is demonstrated.
Anomalous attenuation of extraordinary waves in ionosphere heating experiments: experimental results of 2000-2001
N. A. Zabotin,G. A. Zhbankov,E. S. Kovalenko,V. L. Frolov,G. P. Komrakov,N. A. Mityakov,E. N. Sergeev
Physics , 2001,
Abstract: Multiple scattering from artificial random irregularities HF-induced in the ionosphere F region causes significant attenuation of both ordinary and extraordinary radio waves together with the conventional anomalous absorption of ordinary waves due to their conversion into the plasma waves. To study in detail features of this effect, purposeful measurements of the attenuation of weak probing waves of the extraordinary polarization have been performed at the Sura heating facility. Characteristic scale lengths of the involved irregularities are ~0.1-1 km across the geomagnetic field lines. To determine the spectral characteristics of these irregularities from the extraordinary probing wave attenuation measurements, a simple procedure of the inverse problem solving has been implemented and some conclusions about the artificial irregularity features have been drawn. Theory and details of experiments have been stated earlier. This paper reports results of two experimental campaigns carried out in August 2000 and June 2001 under support of Russian Foundation for Basic Research (grants No. 99-02-17525 and No. 01-02-31008). Particularity of these experiments consisted in using of lower heating power (20-80 MW ERP). Regular character of the multiple scattering effects has been confirmed.
Anomalous attenuation of extraordinary waves in the ionosphere heating experiments
Nikolay A. Zabotin,Andrey G. Bronin,Vladimir L. Frolov,Georgy P. Komrakov,Nikolay A. Mityakov,Eugene N. Sergeev,Gennady A. Zhbankov
Physics , 2001, DOI: 10.1029/2000RS002609
Abstract: Multiple scattering of radio waves by artificial random irregularities HF-induced in the ionosphere F region may cause significant attenuation of both ordinary and extraordinary waves together with common anomalous absorption of ordinary waves due to their non-linear conversion into plasma waves. To demonstrate existence and strength of this effect, direct measurements of attenuation of both powerful pump wave and weak probing waves of extraordinary polarization have been carried out during an experimental campaign on September 6, 7 and 9, 1999 at the Sura heating facility. The attenuation magnitude of extraordinary waves reaches of 1-10 dB over a background attenuation caused by natural irregularities. It is interpreted in the paper on the base of the theory of multiple scattering from the artificial random irregularities with characteristic scale lengths of 0.1-1 km. Simple procedure for determining of irregularity spectrum parameters from the measured attenuation of extraordinary waves has been implemented and some conclusions about the artificial irregularity formation have been obtained.
Pandemic influenza: are we prepared to face our obligations?
Boris P Ehrenstein
Critical Care , 2008, DOI: 10.1186/cc6938
Abstract: In their review recently published in Critical Care, Anantham and coworkers outline the ethical framework that forms the basis of the professional obligations of physicians who respond to health care emergencies, such as an influenza pandemic [1].Bearing in mind the high mortality rates reported for the sporadic human cases of H5N1 avian influenza and experiences gained confronting the recent SARS (severe acute respiratory syndrome) epidemic, many health care professionals will wonder whether we are well prepared to cope with the anticipated influenza pandemic [2,3]. Worldwide, health authorities and many individual institutions have undertaken substantial efforts to plan and prepare for such a catastrophic event. Confronted with the predicted magnitude of a pandemic in reports presented by the mass or professional media, most physicians might feel at least some unease, if not outright fear, about the duties and associated risks they will have to face in the event of an influenza pandemic. After decades of low personal risk for contracting lethal diseases while providing care to patients, physicians -at least in developed countries – are suddenly facing the possibility that occupational risk will increase substantially. If they are not confronted before the onset of an influenza pandemic, these feelings of unease and fear could profoundly hinder individual physicians in fulfilling their professional duties; they could therefore undermine institutional and societal preparations [4-8]. Hence, a reappraisal of the ethical basis of our professional duties as physicians and of justifiable or nonjustifiable limits to these duties should be an integral part of pandemic preparedness efforts, not only for professional organizations and health authorities, but also for individual physicians.In their review, Anantham and coworkers [1] provide explanations of the basic principles of 'the rule of rescue', the 'free choice of the profession' and the implicit 'contract of the medi
Case Study in ER Diagrams in the Context of Development of Generic Visualization Methods
Boris P. Leontyev
Lecture Notes in Engineering and Computer Science , 2008,
Diabetes Technology: Markers, Monitoring, Assessment, and Control of Blood Glucose Fluctuations in Diabetes
Boris P. Kovatchev
Scientifica , 2012, DOI: 10.6064/2012/283821
Diabetes Technology: Markers, Monitoring, Assessment, and Control of Blood Glucose Fluctuations in Diabetes
Boris P. Kovatchev
Scientifica , 2012, DOI: 10.6064/2012/283821
Abstract: People with diabetes face a life-long optimization problem: to maintain strict glycemic control without increasing their risk for hypoglycemia. Since the discovery of insulin in 1921, the external regulation of diabetes by engineering means has became a hallmark of this optimization. Diabetes technology has progressed remarkably over the past 50 years—a progress that includes the development of markers for diabetes control, sophisticated monitoring techniques, mathematical models, assessment procedures, and control algorithms. Continuous glucose monitoring (CGM) was introduced in 1999 and has evolved from means for retroactive review of blood glucose profiles to versatile reliable devices, which monitor the course of glucose fluctuations in real time and provide interactive feedback to the patient. Technology integrating CGM with insulin pumps is now available, opening the field for automated closed-loop control, known as the artificial pancreas. Following a number of in-clinic trials, the quest for a wearable ambulatory artificial pancreas is under way, with a first prototype tested in outpatient setting during the past year. This paper discusses key milestones of diabetes technology development, focusing on the progress in the past 10 years and on the artificial pancreas—still not a cure, but arguably the most promising treatment of diabetes to date. 1. Introduction In health, glucose metabolism is tightly controlled by a hormonal network including the gut, the liver, the pancreas, and the brain to ensure stable fasting blood glucose (BG) levels and transient postprandial glucose fluctuations. In diabetes, this network control is disrupted by deficiency or absence of insulin secretion and/or insulin resistance, which has to be compensated by technological means. Generally, people with diabetes are classified into type 1 and the much more prevalent type 2 diabetes accounting for 90–95% of all cases. Type 1 diabetes is characterized by absolute deficiency of insulin secretion resulting from autoimmune response targeting the β-cells of the pancreas; type 2 diabetes is triggered by a combination of resistance to insulin and insufficient β-cell function [1]. For the 1,900 years following the clinical introduction of the term diabetes (Aretaeus the Cappadocian, 1st Century AD) diet was the only, albeit unsuccessful, treatment. In the 19th century, it was understood that diabetes is a complex of disorders characterized by a common final element of hyperglycemia (elevated blood sugar levels). With the discovery of insulin in 1921 by Frederick Banting at the
Mysteries and Unknows of Single Bubble Sonoluminescence from Viewpoint of Plasma Spectroscopy
Boris P. Lavrov
Physics , 2001,
Abstract: UV continua observed in multi-bubble and single-bubble sonoluminescence spectra of hydrogen-containing liquids have the same physical nature - radiative dissociation of electronically excited hydrogen molecules (and possibly hydrides of heavy rare gases like ArH). In the case of SBSL of "air bubble in water" the oscillating bubble actually consists of a hydrogen/argon mixture with periodically changing amount of water vapor. The proposed mechanism is able to explain all available spectroscopic observations without any exotic hypothesis but in terms usual for plasma spectroscopy.
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