164 research outputs found

    Resonance nonlinear reflection from neutron star and additional radiation components of Crab pulsar

    Get PDF
    Additional high-frequency components of the pulsar radiation in Crab Nebula are considered as a result of the resonance with the surface electromagnetic wave at nonlinear reflection from of the neutron star surface.This stimulated scattering consists in generation of a surface periodic relief by an incident field and diffraction on that relief the radiation of relativistic positrons, which fly from the magnetosphere to the star in the accelerating electric field of a polar gap.Comment: 6 pages, 2 figures; The Report on the Conference "PLASMA ELECTRONICS AND NEW ACCELERATION METHODS" 27-31 August 2018, Kharkov, Ukraine. We have added some figures, refs, footnotes and clarified some notation in the tex

    Модифицированная гемокоррекция в комплексном лечении больных с гнойно-воспалительными заболеваниями легких

    Get PDF
    Objective: To evaluate the efficiency of extracorporeal hemocorrection used in the complex therapy in patients with a pyoinflammatory process in the lung.Materials and methods: 62 patients, including 22 patients with lung abscess who underwent routine plasmapheresis and 40 patients with varying pyoinflammatory lung diseases who received modified hemocorrection — plasma exchange combined with laser extracorporeally washed-off cytomass irradiation, were examined and treated. The severity of their general condition was assessed by the SAPS scale and the severity of intoxication was evaluated by the content of low and medium-molecular weight substances (LMMWSs). The hemostatic system was studied by standardized studies.Results. Routine plasmapheresis was established to produce no impact on platelet functional activity within the first 24 hours and, three days later, promoted the progression of disseminated intravascular coagulation. A combination of plasma exchange and laser extracorporeally washed-off cytomass irradiation in patients with pyoinflam-matory lung diseases was attended by a lower blood coagulative activity and plasmin stabilization with attenuated throm-binemia. The plasma and erythrocytic levels of LMMWSs decreased and their urinary concentrations increased, which is indicative of the body’s detoxification block disorders irrespective of the severity of the disease.Conclusion. It is expedient to apply the plasma-exchanging technique in combination with laser extracorporeally washed-off cytomass irradiation to patients with the uncomplicated and complicated course of pulmonary pyoinflammatory processes without the signs of multiple organ dysfunction on admission to a specialized hospital. Цель исследования . Оценить эффективность использования экстракорпоральной гемокоррекции в комплексной терапии больных с гнойно-воспалительными процессами в легких.Материалы и методы. Обследовано и пролечено 62 больных, из них 22 пациента с абсцессом легких, которым проводился традиционный плазмаферез, и 40 больных с гнойно-воспалительными заболеваниями легких разной степени тяжести, получавшие модифицированную гемокор-рекцию — плазмообмен, сочетанный с лазерным облучением экстракорпорально отмытой цитомассы. Тяжесть общего состояния оценивали по шкале SAPS, а тяжесть интоксикации — по содержанию веществ низкой и средней молекулярной массы (ВНСММ). Стандартизованными методами исследовали систему гемостаза.Результаты. Установлено, что традиционный плазмаферез не оказывает влияния на функциональную активность тромбоцитов в течение первых суток, а через трое суток способствует прогрессированию диссеминированного внутрисосудистого свертывания крови. Сочетание плазмообмена с лазерным облучением экстракорпорально отмытой цитомассы у больных с гнойно-воспалительными заболеваниями легких сопровождается снижением активности свертывающей системы крови, стабилизацией плазмина на фоне снижения выраженности тромбинемии. Уменьшается содержание ВНСММ в плазме и на эритроцитах и значительно повышается их концентрация в моче, что свидетельствует о дебло-каде системы детоксикации организма независимо от тяжести заболевания,Заключение. Метод плазмообмена, сочетанного с лазерным облучением экстракорпорально отмытой цитомассы, целесообразно применять у больных с неосложненным и осложненным течением гнойно-воспалительных процессов в легких без явлений полиорганной недостаточности в раннем периоде госпитализации в специализированный стационар.

    A model of direction selectivity in the starburst amacrine cell network

    Get PDF
    Displaced starburst amacrine cells (SACs) are retinal interneurons that exhibit GABAA receptor-mediated and Cl− cotransporter-mediated, directionally selective (DS) light responses in the rabbit retina. They depolarize to stimuli that move centrifugally through the receptive field surround and hyperpolarize to stimuli that move centripetally through the surround (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006). They also play a key role in the activity of DS ganglion cells (DS GC; Amthor et al, Vis Neurosci 19:495–509 2002; Euler et al, Nature 418:845–852, 2002; Fried et al, Nature 420:411– 414, 2002; Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799 2006; Yoshida et al, Neuron 30:771–780, 2001). In this paper we present a model of strong DS behavior of SACs which relies on the GABA-mediated communication within a tightly interconnected network of these cells and on the glutamate signal that the SACs receive from bipolar cells (a presynaptic cell that receives input from cones). We describe how a moving light stimulus can produce a large, sustained depolarization of the SAC dendritic tips that point in the direction that the stimulus moves (i.e., centrifugal motion), but produce a minimal depolarization of the dendritic tips that point in the opposite direction (i.e., centripetal motion). This DS behavior, which is quantified based on the relative size and duration of the depolarizations evoked by stimulus motion at dendritic tips pointing in opposite directions, is robust to changes of many different parameter values and consistent with experimental data. In addition, the DS behavior is strengthened under the assumptions that the Cl− cotransporters Na + -K + -Cl − and K + -Cl − are located in different regions of the SAC dendritic tree (Gavrikov et al, PNAS 103(49):18793–18798, 2006) and that GABA evokes a long-lasting response (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799, 2006). A possible mechanism is discussed based on the generation of waves of local glutamate and GABA secretion, and their postsynaptic interplay as the waves travel between cell compartments

    WAYS TO REDUCE ERRORS IN MEASURING THE DIELECTRIC CONSTANT OF WEAKLY ABSORBING DIELECTRICS IN THE MILLIMETER AND SUBMILLIMETER (TERAHERTZ) WAVELENGTH RANGES BY THE SURFACE PLASMON RESONANCE METHOD

    Get PDF
    Subject and Purpose. The sources of errors are identified that may arise in the course of terahertz-range measurements of the dielectric constant of weakly absorbent dielectrics, if performed within the surface plasmon resonance (SPR) technique. Possible ways are analyzed for reducing or fully eliminating such errors. Methods and Methodology. Specific details of applying the SPR method for dielectric constant measurements have been analyzed, with the aim of identifying the major factors that particularly affect the measurement accuracy. Results. It has been noted that in order to reduce the level of backlight interference (which may lead to blinding the receiver), it is expedient to make surface resonance records via frequency scanning. In that case the impact of the interference signal nonstationarity arising from the partial conversion of the surface wave energy into that of the volume wave, which occurs at the grating edges, is markedly lower than in the case of angular scanning. A mathematical expression has been derived which suggests a relation between scanning step sizes in angle and in frequency (for the angular and frequency scanning, respectively). As has been shown, a better measurement accuracy is achievable if the SPR is recorded as a function of frequency. Indeed, the frequency can be varied, with the use of familiar technologies, in steps of a much smaller size than such adopted for angular scanning. Errors in the above measurements can also arise if the resonance is excited on a grating whose Fourier spectrum contains many high-frequency components which carry a noticeable portion of the diffracted radiation energy. These energy losses can be greatly reduced if the SPR is excited on a grating whose profile involves the lowest number of spatial Fourier harmonics. Conclusions. The method suggested allows a significant reduction in the level of errors of the dielectric constant measurements in weakly absorbing dielectrics if the surface plasmon resonance effects are registered in dependence on the incident frequency, while the SPR is excited at a diffraction grating whose troughs-and-peaks profile is close to harmonical

    The UA9 experimental layout

    Full text link
    The UA9 experimental equipment was installed in the CERN-SPS in March '09 with the aim of investigating crystal assisted collimation in coasting mode. Its basic layout comprises silicon bent crystals acting as primary collimators mounted inside two vacuum vessels. A movable 60 cm long block of tungsten located downstream at about 90 degrees phase advance intercepts the deflected beam. Scintillators, Gas Electron Multiplier chambers and other beam loss monitors measure nuclear loss rates induced by the interaction of the beam halo in the crystal. Roman pots are installed in the path of the deflected particles and are equipped with a Medipix detector to reconstruct the transverse distribution of the impinging beam. Finally UA9 takes advantage of an LHC-collimator prototype installed close to the Roman pot to help in setting the beam conditions and to analyze the efficiency to deflect the beam. This paper describes in details the hardware installed to study the crystal collimation during 2010.Comment: 15pages, 11 figure, submitted to JINS

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

    Get PDF
    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

    Get PDF
    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Expression and Localization of CLC Chloride Transport Proteins in the Avian Retina

    Get PDF
    Members of the ubiquitously expressed CLC protein family of chloride channels and transporters play important roles in regulating cellular chloride and pH. The CLCs that function as Cl−/H+ antiporters, ClCs 3–7, are essential in particular for the acidification of endosomal compartments and protein degradation. These proteins are broadly expressed in the nervous system, and mutations that disrupt their expression are responsible for several human genetic diseases. Furthermore, knock-out of ClC3 and ClC7 in the mouse result in the degeneration of the hippocampus and the retina. Despite this evidence of their importance in retinal function, the expression patterns of different CLC transporters in different retinal cell types are as yet undescribed. Previous work in our lab has shown that in chicken amacrine cells, internal Cl− can be dynamic. To determine whether CLCs have the potential to participate, we used PCR and immunohistochemical techniques to examine CLC transporter expression in the chicken retina. We observed a high level of variation in the retinal expression levels and patterns among the different CLC proteins examined. These findings, which represent the first systematic investigation of CLC transporter expression in the retina, support diverse functions for the different CLCs in this tissue
    corecore