101 research outputs found
Automated methodology for adjustment of component values in passive converter circuit for wind turbine generators
The current paper proposes an automated design approach for a previously developed passive converter circuits for wind turbine generators. This suggested approach allows to calculate the components for all passive converter circuits approved in European patent number PCT/EP2010/055637, where only minor changes in the source code of the mathematical and simulation software have to be made when different circuits are involved. An optimisation based on steepest descent method results in power/frequency (power/speed) curve that matches well the cubic dependence (Pwtmax~ω3) of the extracted power
General slow-roll Inflation in f(R) gravity under the Palatini approach
Producción CientíficaSlow-roll inflation is analyzed in the context of modified gravity within the Palatini formalism. As shown in the literature, inflation in this framework requires the presence of non-traceless matter; otherwise, it does not occur just as a consequence of the nonlinear gravitational terms of the action. Nevertheless, by including a single scalar field that plays the role of the inflaton, slow-roll inflation can be performed in these theories, where the equations lead to an effective potential that modifies the dynamics. We obtain the general slow-roll parameters and analyze a simple model to illustrate the differences introduced by the gravitational terms under the Palatini approach, and the modifications on the spectral index and the tensor to scalar ratio predicted by the model.Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP08052034)
General slow-roll inflation in gravity under the Palatini approach
Slow-roll inflation is analyzed in the context of modified gravity within the
Palatini formalism. As shown in the literature, inflation in this framework
requires the presence of non-traceless matter, otherwise it does not occur just
as a consequence of the non-linear gravitational terms of the action.
Nevertheless, by including a single scalar field that plays the role of the
inflaton, slow-roll inflation can be performed in these theories, where the
equations lead to an effective potential that modifies the dynamics. We obtain
the general slow-roll parameters and analyze a simple model to illustrate the
differences introduced by the gravitational terms under the Palatini approach,
and the modifications on the spectral index and the tensor to scalar ratio
predicted by the model.Comment: 11 pages, version publishe
Exoplanets Bouncing Between Binary Stars
Exoplanetary systems are found not only among single stars, but also binaries
of widely varying parameters. Binaries with separations of 100--1000 au are
prevalent in the Solar neighborhood; at these separations planet formation
around a binary member may largely proceed as if around a single star. During
the early dynamical evolution of a planetary system, planet--planet scattering
can eject planets from a star's grasp. In a binary, the motion of a planet
ejected from one star has effectively entered a restricted three-body system
consisting of itself and the two stars, and the equations of motion of the
three body problem will apply as long as the ejected planet remains far from
the remaining planets. Depending on its energy, escape from the binary as a
whole may be impossible or delayed until the three-body approximation breaks
down, and further close interactions with its planetary siblings boost its
energy when it passes close to its parent star. Until then this planet may be
able to transition from the space around one star to the other, and chaotically
`bounce' back and forth. In this paper we directly simulate scattering
planetary systems that are around one member of a circular binary, and quantify
the frequency of bouncing in scattered planets. We find that a great majority
(70 to 85 per cent) of ejected planets will pass at least once through the
space of it's host's binary companion, and depending on the binary parameters
about 45 to 75 per cent will begin bouncing. The time spent bouncing is roughly
log-normally distributed with a peak at about years, with only a small
percentage bouncing for more than a Myr. This process may perturb and possibly
incite instability among existing planets around the companion star. In rare
cases, the presence of multiple planets orbiting both stars may cause
post-bouncing capture or planetary swapping.Comment: MNRAS in press. Animations of some orbits can be viewed at
http://www.ast.cam.ac.uk/~moeckel/bouncingplanets.htm
Psychophysiological Status and Life Quality in Individuals with Metabolic Syndrome Living in Central Kazakhstan
BACKGROUND: Morbidity rate of circulatory system diseases (CSD) in Kazakhstan continues to grow and the metabolic syndrome (MetS) contributes significantly to cardiovascular risk development. It was known that MetS altered autonomic nervous system (ANS) by decreasing parasympathetic activity and global heart rate variability (HRV), at the same time, the decrease in sympathetic modulation is unclear. Studies investigated associations between anxiety and MetS disorders are rather controversial. Research findings of the MetS influence on health-related quality of life (HRQoL) were also contradictory. The above-mentioned justifies the necessity of research to clarify and deepen the MetS etiology and pathogenesis, as well as to improve its diagnostics efficiency and treatment.
AIM: The research goals were to study psychophysiological status and HRQoL in individuals with MetS living in Central Kazakhstan.
MATERIALS AND METHODS: Three hundred MetS patients were examined in Karaganda city clinical hospital. Statistical methods and spectral analysis of HRV, simple visual-motor reaction (SVMR), the Spielberger State-Trait Anxiety Inventory, and the Lüscher color test were used. SF-36 questionnaire was used for HRQoL assessment.
RESULTS: General decrease in the activity of both sympathetic and parasympathetic branches of ANS was observed in MetS patients. More than half of the examined MetS patients have had a high level of trait anxiety. Most MetS patients have had a low level of the central nervous system (CNS) functional activity. MetS patients are active both in physical and social spheres. Bodily pain syndrome greatly influences MetS patients’ life quality. The patients evaluate their health level as being low.
CONCLUSION: Individuals with MetS living in Central Kazakhstan had decreased activity of ANS, prevalence of inhibition processes in CNS, high level of trait anxiety, and bodily pain syndrome affecting life quality
Superposition rules for higher-order systems and their applications
Superposition rules form a class of functions that describe general solutions
of systems of first-order ordinary differential equations in terms of generic
families of particular solutions and certain constants. In this work we extend
this notion and other related ones to systems of higher-order differential
equations and analyse their properties. Several results concerning the
existence of various types of superposition rules for higher-order systems are
proved and illustrated with examples extracted from the physics and mathematics
literature. In particular, two new superposition rules for second- and
third-order Kummer--Schwarz equations are derived.Comment: (v2) 33 pages, some typos corrected, added some references and minor
commentarie
Бронхиальные осложнения после трансплантации легких
Bronchial complications are among the main causes of impairing postoperative period and thansplant failure. Severe bronchial complications are very rare but have a high mortality rate. Light forms decrease transplant function and while progressing can leads to life-threatening conditions without required treatment. Nowadays there is a huge necessity in classification of diagnostic and bronchial complications treatment on different terms after lung transplantation. Methods of observation bronchoscopy and interventional bronchology are allowing us to realize prevention, diagnostic and treatment bronchial complications.Бронхиальные осложнения являются одной из основных причин тяжелого течения послеоперационного периода и неблагоприятных исходов у реципиентов донорских легких. Несмотря на относительно низкую частоту тяжелых форм бронхиальных осложнений, последние определяют высокую летальность, в то время как легкие формы бронхиальных осложнений без необходимого лечения значительно ухудшают функцию трансплантата и качество жизни реципиента, прогрессируя, приводят к жизнеугрожающим состояниям. Несмотря на обилие научных публикаций, существует потребность в систематизации подходов к диагностике и лечению бронхиальных осложнений на разных сроках после трансплантации, оценке роли обсервационной бронхоскопии и методов интервенционной бронхологии в профилактике, диагностике и лечении бронхиальных осложнений
СОВРЕМЕННЫЕ АСПЕКТЫ ЛЕЧЕНИЯ СТЕНОЗОВ ГОРТАНИ И ТРАХЕИ ПОСЛЕ ФУНКЦИОНАЛЬНО-ЩАДЯЩИХ ОПЕРАЦИЙ
Treatment and rehabilitation of patients with cancer of the larynx is a complex issue, as the majority of patients (60-70%) are diagnosed at the III and IV stages of the disease. The main type of surgery is a laryngectomy which leads to organ dysfunction and disability. It is known that in cases of locally advanced laryngeal tumors resection may be performed. However, after these operations from 22 to 57% of patients couldn’t be rehabilitated due to the difficulty in creating of sufficient lumen of the larynx, development of chondroperihondritis, growth of granulation tissue, fibrosis formation and stenosis of the larynx (Bukhman L.A., 1982; Bityutskij P.T., 1990; Park H.Y., 2009; SoYeonLimatal, 2012).Лечение и реабилитация больных раком гортани является сложной проблемой, так как большинство больных (60–70%) поступают на лечение в 3 и 4 стадиях заболевания. Основным видом хирургического вмешательства является ларингэктомия которая приводит к нарушению функций органа и инвалидизации. Известно, что при местно – распространенных опухолях гортани возможно выполнение резекций. Однако после этих операций н удается реабилитировать от 22 до 57% больных вследствие трудностей при создании достаточного просвета гортани, развития хондроперихондрита, роста грануляций, образования рубцов и стеноза этого органа. (Л. А. Бухман 1982г, П. Т. Битюцкий 1990, Park H. Y., 2009; SoYeonLimatal., 2012 и др. соавторы)
- …