178 research outputs found

    Cool spots on the surface of the active giant PZ Mon

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    Based on the multiband (BVRIJHKL) photometric observations of the active red giant PZ Mon performed for the first time in the winter season of 2017-2018, we have determined the main characteristics of the spotted stellar surface in a parametric three-spot model. The unspotted surface temperature is Teff=4730 K, the temperature of the cool spots is Tspot=3500 K, their relative area is about 41%, and the temperature of the warm spots is Twarm=4500 K with a maximum relative area up to 20%. The distribution of spots over the stellar surface has been modeled. The warm spots have been found to be distributed at various longitudes in the hemisphere on the side of the secondary component and are most likely a result of its influence.Comment: 5 pages, 7 figure

    Breather Modes Induced by Localized RF Radiation: Analytical and Numerical Approaches

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    Numerical computations and collective variables approach are applied to analytical and numerical study of spatially localized excitations of one-dimensional magnetic system in external high-frequency magnetic field. It is demonstrated the hysteresis character of dependence for amplitude of local soliton-like states on external field magnitude. The system shows a variety of interesting nonlinear phenomena such as periodicity doubling and chaos

    Influence of laser surface hardening on corrosion properties of Al-Zn-Si cast alloy

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    This work is focused on the effect of the laser surface treatment (laser power 50 and 80 W) on microstructure and corrosion properties of self-hardened AlZn10Si8Mg cast alloy used for engine and vehicle constructions. The electrochemical impedance spectroscopy (EIS) technique and Nyquist plots in a 1M NaCl test solution at 20 °C were carried out. A detailed corrosion study showed that corrosion resistance samples with laser layer were marginally less; probably the presence of chloride ions significantly damaged the Al2O3 film and caused the formation of NaAlO2

    Influence of laser surface hardening on corrosion properties of Al-Zn-Si cast alloy

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    This work is focused on the effect of the laser surface treatment (laser power 50 and 80 W) on microstructure and corrosion properties of self-hardened AlZn10Si8Mg cast alloy used for engine and vehicle constructions. The electrochemical impedance spectroscopy (EIS) technique and Nyquist plots in a 1M NaCl test solution at 20 °C were carried out. A detailed corrosion study showed that corrosion resistance samples with laser layer were marginally less; probably the presence of chloride ions significantly damaged the Al2O3 film and caused the formation of NaAlO2

    The research of the maximum wind speed in Tomsk and calculations of dynamic load on antenna systems

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    The work is concerned with calculations and analysis of the maximum wind speed in Tomsk city. The data for analysis were taken from the TOR-station located in the north-eastern part of the city. The TOR-station sensors to measure a speed and a direction of wind are installed on the 10-meter meteorological mast. Wind is measured by M-63, which uses the standard approach and the program with one-minute averaging for wind gusts recording as well. According to the measured results in the research performed, the estimation of the dynamic and wind load on different types of antenna systems was performed. The work shows the calculations of wind load on ten types of antenna systems, distinguished by their different constructions and antenna areas. For implementation of calculations, we used methods developed in the Central Research and Development Institute of Building Constructions named after V.A. Kucherenko. The research results could be used for design engineering of the static antenna systems and mobile tracking systems for the distant objects

    Muscle Carnosine Is Associated with Cardiometabolic Risk Factors in Humans

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    Background Carnosine is a naturally present dipeptide abundant in skeletal muscle and an over-the counter food additive. Animal data suggest a role of carnosine supplementation in the prevention and treatment of obesity, insulin resistance, type 2 diabetes and cardiovascular disease but only limited human data exists. Methods and Results Samples of vastus lateralis muscle were obtained by needle biopsy. We measured muscle carnosine levels (high-performance liquid chromatography), % body fat (bioimpedance), abdominal subcutaneous and visceral adiposity (magnetic resonance imaging), insulin sensitivity (euglycaemic hyperinsulinemic clamp), resting energy expenditure (REE, indirect calorimetry), free-living ambulatory physical activity (accelerometers) and lipid profile in 36 sedentary non-vegetarian middle aged men (45±7 years) with varying degrees of adiposity and glucose tolerance. Muscle carnosine content was positively related to % body fat (r = 0.35, p = 0.04) and subcutaneous (r = 0.38, p = 0.02) but not visceral fat (r = 0.17, p = 0.33). Muscle carnosine content was inversely associated with insulin sensitivity (r = -0.44, p = 0.008), REE (r = -0.58, p<0.001) and HDL-cholesterol levels (r = -0.34, p = 0.048). Insulin sensitivity and physical activity were the best predictors of muscle carnosine content after adjustment for adiposity. Conclusion Our data shows that higher carnosine content in human skeletal muscle is positively associated with insulin resistance and fasting metabolic preference for glucose. Moreover, it is negatively associated with HDL-cholesterol and basal energy expenditure. Intervention studies targeting insulin resistance, metabolic and cardiovascular disease risk factors are necessary to evaluate its putative role in the prevention and management of type 2 diabetes and cardiovascular disease

    Assessing cytokine status of patients with chronic endometritis combined with endometrial hyperplastic processes in reproductive period

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    The goal of our study was to examine local and serum cytokine level involved in regulating inflammation in patients with chronic endometritis combined with endometrial hyperplastic processes. On admission, all patients underwent hysteroscopy with separate diagnostic curettage followed by histological examination of samples isolated from the uterine and cervical canal mucosa. Such manipulations were indicated due to abnormal uterine bleeding as well as suspected endometrial pathology based on ultrasound examination. According to the histological examination data of the endometrial samples, all patients were divided into two groups: group I contained 45 women with CE combined with PEG without atypia; group II — 38 patients with morphologically verified CEE combined with AEG without atypia. Level of IL-1P, IL-2, IL-6, IFNy, TNFa in biological fluids (aspirate from the uterus; serum) was measured by using enzyme-linked immunosorbent assay. We found that in both groups (91.1% and 89.6%, respectively) the vast majority of patients was hospitalized due to abnormal uterine bleeding. Oligomenorrhea alternated with intermenstrual bleeding (66.7% and 71.2%, respectively) and dominated in pattern of menstrual cycle disorders in the examined patients, whereas 11 (24.4%) and 7 (18.4%) patients from group I and II, respectively, were noted to suffer from severe menstrual bleeding. Overall, analyzing the data on cytokine level both in the uterine aspirate and serum evidences about ongoing inflammatory process found at examination time point. Upon that, such process was not only local, but also exhibited signs of a systemic inflammatory response. The data on cytokine level in the uterine aspirate from patients with CE coupled to PGE or CGE without atypia point at local inflammatory process characterized by significantly increased concentration of IL-ф, IL-2, IL-6, TNFa and IFNy. At the same time, higher level of IL-ф and IFNy in patients from group II might indicates that degree of morphological changes in the endometrium could affect the level of local cytokine production. Thus, the data obtained evidence that immune changes in chronic endometritis combined with non-atypical endometrial hyperplastic processes mostly occur locally. In this regard, measuring cytokine concentration in the uterine aspirate is a diagnostic predictor and serves as a sign for monitoring therapeutic effectiveness of therapy in this cohort of patients

    The perspective soft spring wheat variety Semenovna is the result of international cooperation

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    The research is aimed at studying economically valuable traits and genetic control of resistance to leaf-stem diseases, photoperiodic reaction and short stemming of soft spring wheat variety Semenovna, created by scientists of the Omsk Agrarian Scientific Center (Russia) and the North Kazakhstan Agricultural Experimental Station (Kazakhstan). Using methods of state variety testing, molecular genetics and in vitro methods, morphological features of a new variety, features of its development have been described, the yield level at different ecological test points for three years (2015-2017) has been analyzed. The studies conducted at two ecological points made it possible to select a medium-sized promising line of soft spring wheat (Lutescens 354/04-6), which was transferred to the State Registration Service of the Republic of Kazakhstan and after two years of testing was included into the State Register of the Republic of Kazakhstan under the name Semenovna (patent No. 1023). In terms of grain quality, it was at the level of valuable wheat, exceeded the standard in protein content by 1-2 % and raw gluten by 3-4 %. The new medium-ripe Semenovna variety combines increased yield (2.73-4.40 t/ha) with resistance to drought (resistance index Ir = 0.57), brown and stem rust (IU = 0.00-0.23). The genotype of the variety contains wheat-rye translocation 1RS.1BL (with a cluster of Lr26/Sr31/Pm8/Yr9 genes). The medium-stem variety carries the Rht8b allele in its genotype (174 bp)  and is photosensitive to the length of the day (allele 414 bp). The parameters of ecological plasticity of the new variety are determined: linear regression coefficient (bi = 1.08), stability index (σd2 = 0.27)

    Late-spring and summertime tropospheric ozone and NO2 in western Siberia and the Russian Arctic : regional model evaluation and sensitivities

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    We use a regional chemistry transport model (Weather Research and Forecasting model coupled with chemistry, WRF-Chem) in conjunction with surface observations of tropospheric ozone and Ozone Monitoring Instrument (OMI) satellite retrievals of tropospheric column NO2 to evaluate processes controlling the regional distribution of tropospheric ozone over western Siberia for late spring and summer in 2011. This region hosts a range of anthropogenic and natural ozone precursor sources, and it serves as a gateway for near-surface transport of Eurasian pollution to the Arctic. However, there is a severe lack of in situ observations to constrain tropospheric ozone sources and sinks in the region. We show widespread negative bias in WRF-Chem tropospheric column NO2 when compared to OMI satellite observations from May-August, which is reduced when using ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants) v5a emissions (fractional mean bias (FMB) = -0.82 to -0.73) compared with the EDGAR (Emissions Database for Global Atmospheric Research)-HTAP (Hemispheric Transport of Air Pollution) v2.2 emissions data (FMB = -0.80 to -0.70). Despite the large negative bias, the spatial correlations between model and observed NO2 columns suggest that the spatial pattern of NOx sources in the region is well represented. Scaling trans-port and energy emissions in the ECLIPSE v5a inventory by a factor of 2 reduces column NO2 bias (FMB = -0.66 to -0.35), but with overestimates in some urban regions and little change to a persistent underestimate in background regions. Based on the scaled ECLIPSE v5a emissions, we assess the influence of the two dominant anthropogenic emission sectors (transport and energy) and vegetation fires on surface NOx and ozone over Siberia and the Russian Arctic. Our results suggest regional ozone is more sensitive to anthropogenic emissions, particularly from the transport sector, and the contribution from fire emissions maximises in June and is largely confined to latitudes south of 60 degrees N. Ozone dry deposition fluxes from the model simulations show that the dominant ozone dry deposition sink in the region is to forest vegetation, averaging 8.0 Tg of ozone per month, peaking at 10.3 Tg of ozone deposition during June. The impact of fires on ozone dry deposition within the domain is small compared to anthropogenic emissions and is negligible north of 60 degrees N. Overall, our results suggest that surface ozone in the region is controlled by an interplay between seasonality in atmospheric transport patterns, vegetation dry deposition, and a dominance of transport and energy sector emissions.Peer reviewe
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