401 research outputs found

    J1154+2443: a low-redshift compact star-forming galaxy with a 46 per cent leakage of Lyman continuum photons

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    We report the detection of the Lyman continuum (LyC) radiation of the compact star-forming galaxy (SFG) J1154+2443 observed with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope. This galaxy, at a redshift of z=0.3690, is characterized by a high emission-line flux ratio O32=[OIII]5007/[OII]3727=11.5. The escape fraction of the LyC radiation fesc(LyC) in this galaxy is 46 per cent, the highest value found so far in low-redshift SFGs and one of the highest values found in galaxies at any redshift. The narrow double-peaked Lya emission line is detected in the spectrum of J1154+2443 with a separation between the peaks Vsep of 199 km/s, one of the lowest known for Lya-emitting galaxies, implying a high fesc(Lya). Comparing the extinction-corrected Lya/Hb flux ratio with the case B value we find fesc(Lya) = 98 per cent. Our observations, combined with previous detections in the literature, reveal an increase of O32 with increasing fesc(LyC). We also find a tight anticorrelation between fesc(LyC) and Vsep. The surface brightness profile derived from the COS acquisition image reveals a bright star-forming region in the centre and an exponential disc in the outskirts with a disc scale length alpha=1.09 kpc. J1154+2443, compared to other known low-redshift LyC leakers, is characterized by the lowest metallicity, 12+logO/H=7.65+/-0.01, the lowest stellar mass M*=10^8.20 Msun, a similar star formation rate SFR=18.9 Msun/yr and a high specific SFR of 1.2x10^-7 yr^-1.Comment: 16 pages, 8 figures, accepted for publication in MNRAS. arXiv admin note: text overlap with arXiv:1605.0516

    Atomic Force Microscopy of Structural-Mechanical Properties of Polyethylene Reinforced by Silicate Needle-Shaped Filler

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    The paper presents the results of experimental studies of polyethylene-based composites reinforced with silicate needle-shaped filler (palygorskite) of different mass fraction (0, 5, 10, and 15%). These composites are less flammable and fire toxic than unfilled polyethylene. The structure (size, shape, and agglomeration of filler) and local mechanical properties of composites in nonstretched and elongated states were investigated by AFM. In stretched samples palygorskite takes a wavy shape, and at extremely high elongation the filler is orthogonal to the axis of tension. The smooth surfaces of the samples, required for AFM, were prepared using the heating/cooling procedure

    On a possibility of inelasticity partial coefficient K sub gamma determination in pi C and pi Pb interactions at 10 to the 14th power eV (experiment PAMIR 1)

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    The investigation of hadron-nuclear interactions in Pamir experiment is carried out by means of X-ray emulsion chambers of two types: carbon (C) and lead (Pb). While comparing the results from the chambers of both types it was found a discrepancy in n sub h and E sub h(1)R values. The observed discrepancy in C and Pb chambers is connected with the difference in values of effective coefficients of energy transfer to the soft component K sub eff for C and Pb chambers

    The formation and development of the managerial personnel reserve on the example of the Tatarstan republic

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    The article describes the practice of formation the personnel reserve in government and administration of the Tatarstan Republic. Also presents an analysis of candidates for inclusion on the roster consisting of three interconnected successive stages- preparatory, competitive and evolving. The authors emphasize the usage of working with a reserve by the structural subdivisions of the human control and power, as well as individual activity types of reservists

    The Effect of pre-incubation duration of soil-biochar model mixtures on the results of determination the intensity of substrate-induced respiration (Methodological aspects of study)

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    Was studied in laboratory experiments the effect of short term (3 days) and long term (95 and 187 days) pre-incubation of soil-biochar model mixes (ratio 20:1) in optimal conditions for the microorganisms on the results of definition the intensity of substrate induced respiration. For experiments 10 biochar samples were used. The biochars were produced from the woody and herbaceous materials under different pyrolysis conditions. Is revealed the heterogeneous influence of biochar by direction and dynamics on the rate of substrate induced respiration depending on the pre-incubation time of model mixtures. It is shown that the prolonged pre-incubation of biochar with soil material under optimal levels of moisture and temperature is a prerequisite for the correct formulation of laboratory experiments and provides a reliable assessment of the impact of biochar on a soil respiration. We can recommend the duration of pre-incubation 3-5 months

    Interleukin-11 Drives Early Lung Inflammation during Mycobacterium tuberculosis Infection in Genetically Susceptible Mice

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    IL-11 is multifunctional cytokine whose physiological role in the lungs during pulmonary tuberculosis (TB) is poorly understood. Here, using in vivo administration of specific antibodies against IL-11, we demonstrate for the first time that blocking IL-11 diminishes histopathology and neutrophilic infiltration of the lung tissue in TB-infected genetically susceptible mice. Antibody treatment decreased the pulmonary levels of IL-11 and other key inflammatory cytokines not belonging to the Th1 axis, and down-regulated IL-11 mRNA expression. This suggests the existence of a positive feedback loop at the transcriptional level, which is further supported by up-regulation of IL-11 mRNA expression in the presence of rIL-11 in in vitro cultures of lung cells. These findings imply a pathogenic role for IL-11 during the early phase of Mycobacterium tuberculosis-triggered disease in a genetically susceptible host

    Numerical simulations of aggregate breakup in bounded and unbounded turbulent flows

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    Breakup of small aggregates in fully developed turbulence is studied by means of direct numerical simulations in a series of typical bounded and unbounded flow configurations, such as a turbulent channel flow, a developing boundary layer, and homogeneous isotropic turbulence. Aggregate breakup occurs when the local hydrodynamic stress σ∼ε1/2\sigma\sim \varepsilon^{1/2}, where ε\varepsilon is the energy dissipation at the position of the aggregate, overcomes a given threshold σcr\sigma_\mathrm{cr}, characteristic for a given type of aggregates. Results show that the breakup rate decreases with increasing threshold. For small thresholds, it develops a universal scaling among the different flows. For high thresholds, the breakup rates show strong differences among the different flow configurations, highlighting the importance of non-universal mean-flow properties. To further assess the effects of flow inhomogeneity and turbulent fluctuations, results are compared with those obtained in a smooth stochastic flow. Furthermore, we discuss limitations and applicability of a set of independent proxies
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