22 research outputs found

    Narrow escape: how ionizing photons escape from disc galaxies

    Full text link
    In this paper we calculate the escape fraction (fescf_{\rm esc}) of ionizing photons from starburst galaxies. Using 2-D axisymmetric hydrodynamic simulations, we study superbubbles created by overlapping supernovae in OB associations. We calculate the escape fraction of ionizing photons from the center of the disk along different angles through the superbubble and the gas disk. After convolving with the luminosity function of OB associations, we show that the ionizing photons escape within a cone of 40\sim 40 ^\circ, consistent with observations of nearby galaxies. The evolution of the escape fraction with time shows that it falls initially as cold gas is accumulated in a dense shell. After the shell crosses a few scale heights and fragments, the escape fraction through the polar regions rises again. The angle-averaged escape fraction cannot exceed [1cos(1radian)]=0.5\sim [1- \cos (1 \, {\rm radian})] = 0.5 from geometrical considerations (using the emission cone opening angle). We calculate the dependence of the time- and angle-averaged escape fraction on the mid-plane disk gas density (in the range n0=0.1550n_0=0.15-50 cm 3^{-3}) and the disk scale height (between z0=10600z_0=10-600 pc). We find that the escape fraction is related to the disk parameters (the mid-plane disk density and scale height) roughly so that fescαn02z03f_{\rm esc}^\alpha n_0^2 z_0^3 (with α2.2\alpha\approx 2.2) is a constant. For disks with a given WNM temperature, massive disks have lower escape fraction than low mass galaxies. For Milky Way ISM parameters, we find fesc5%f_{\rm esc}\sim 5\%, and it increases to 10%\approx 10\% for a galaxy ten times less massive. We discuss the possible effects of clumpiness of the ISM on the estimate of the escape fraction and the implications of our results for the reionization of the universe.Comment: accepted for publication in MNRAS, 19 pages, 18 figure

    Zagreb indices of commuting and non-commuting graphs of finite groups and Hansen-Vuki\v{c}evi\'c conjecture

    Full text link
    In this paper we compute first and second Zagreb indices of commuting and non-commuting graphs of finite groups and determine several classes of finite groups such that their commuting and non-commuting graphs satisfy Hansen-Vuki\v{c}evi\'c conjecture.Comment: 31 page

    Consistency and Variation in Kernel Neural Ranking Model

    Full text link
    This paper studies the consistency of the kernel-based neural ranking model K-NRM, a recent state-of-the-art neural IR model, which is important for reproducible research and deployment in the industry. We find that K-NRM has low variance on relevance-based metrics across experimental trials. In spite of this low variance in overall performance, different trials produce different document rankings for individual queries. The main source of variance in our experiments was found to be different latent matching patterns captured by K-NRM. In the IR-customized word embeddings learned by K-NRM, the query-document word pairs follow two different matching patterns that are equally effective, but align word pairs differently in the embedding space. The different latent matching patterns enable a simple yet effective approach to construct ensemble rankers, which improve K-NRM's effectiveness and generalization abilities.Comment: 4 pages, 4 figures, 2 table

    A Novel Membrane Protein-Specific Serine/Threonine Kinase: Tissue Distribution and Role in Sperm Maturation

    Get PDF
    Our recent studies have described for the first time the purification of an ectoprotein kinase to apparent homogeneity using caprine sperm as the model. Purified ectokinase (CIK) is a novel membrane protein-specific kinase that phosphorylates serine and threonine residues of ectophosphoproteins. This study, using ELISA based on ecto-CIK antibody demonstrates that ecto-CIK level is remarkably higher in the sperm membrane than in the cytosol. The epididymal sperm maturational event as well as sperm vertical velocity is associated with a significant increase in the ecto-CIK level. Ecto-CIK, the membrane protein-specific kinase, is also present in all the tissues tested and is predominantly localized in the cell membrane. Ubiquitous localization of the novel kinase on the mammalian cell membrane suggests that the kinase may play pivotal role in gamete as well as somatic cell regulation by modulating membrane biology through serine/threonine phosphorylation of specific membrane proteins located in the ectodomains

    Study of prescribing pattern of drugs used in the treatment of bronchial asthma at tertiary care hospital of northern India

    Get PDF
    Background: Asthma is a chronic inflammatory disease requiring long term treatment. For an effective control of asthma symptoms background knowledge of the prescribing pattern of anti-asthmatic drugs is a must.Methods: A prospective, observational study was conducted in the Department of Respiratory Medicine OPD, King George's Medical University, Lucknow. 114 patients of asthma were recruited for the study. A case report form was filled from patient’s prescription containing the demographic details of the patients, presenting complaints, investigations and drugs prescribed along with their dose, duration, frequency, route of administration.Results: 114 patients’ prescriptions were assessed which showed average number of drugs per prescription - 3.22. 42.8% and 50% of the drugs were prescribed in accordance with World Health Organization model list of essential medicines and National list of essential medicines. Short acting β2 agonist (salbutamol), 61.4% was the most commonly and frequently prescribed single anti asthmatic drug. Combination of inhaled corticosteroid and long acting β2 agonist, 86.8% was the most commonly prescribed fixed dose combination anti asthmatic drug. Inhalational route (75%) was the most preferred one over oral route (25%).Conclusions: Asthma being a chronic disease requires prolonged treatment which imposes economic burden on the patients. Judicious prescription of drugs not only improves the patient clinically but also removes the unnecessary burden. Data obtained from these studies can be used as a guide to make future decisions regarding standard prescription

    Sperm Motility Regulatory Proteins: A Tool to Enhance Sperm Quality

    Get PDF
    Sperm forward motility is an essential parameter in mammalian fertilization. Studies from our laboratory have identified and characterized a few unique sperm motility regulatory proteins/glycoproteins from the male reproductive fluids and mammalian blood serum. The purified sperm motility-initiating protein (MIP) from caprine epididymal plasma as well as the forward motility-stimulating factor (FMSF) and motility-stimulating protein (MSP) from buffalo and goat serum, respectively, have high efficacy to initiate or increase motility in nonmotile or less motile sperm. Antibody of sperm motility inhibitory factor (MIF-II) has the high potential to enhance sperm vertical velocity and forward motility by increasing intracellular cyclic adenosine monophosphate (cAMP) level. The appearance and disappearance of D-galactose–specific lectin and its receptor along the epididymis has been reported to be involved in motility regulation in spermatozoa. A novel synthetic cryopreservation method and role of lipid to protect membrane damage during cryopreservation have been demonstrated. Motility-promoting proteins may be extremely useful for improving cattle breeding and breeding of endangered species, thereby helping in enhanced production of animal products as well as in the conservation of animals. Isolated proteins and developed cryopreservation technology may also be beneficial in human infertility clinics to increase the chance of fertilization

    Novel Microbial System Developed from Low-Level Radioactive Waste Treatment Plant for Environmental Sustenance

    Get PDF
    A packed bed bioreactor efficiently treated low-level radioactive waste for years with a retention time of 24 h using acetate as the sole carbon source. However, there was generation of dead biomass. This bioreactor biomass was used to develop a bacterial consortium, which could perform the function within 4 h while simultaneously accumulating nitrate and phosphate. The dead mass was negligible. Serial dilution technique was used to isolate the world’s first pure culture of a nitrate accumulating strain from this consortium. This isolate could simultaneously accumulate nitrate and phosphate from solution. Its ability to form biofilm helped develop a packed bed bioreactor system for waste water treatment, which could optimally remove 94.46% nitrate within 11 h in batch mode while 8 h in continuous mode from waste water starting from 275 ppm of nitrate. The conventional approach revealed the strain to be a member of genus Bacillus but showed distinct differences with the type strains. Further insilico analysis of the draft genome and the putative protein sequences using the bioinformatics tools revealed the strain to be a novel variant of genus Bacillus. The sequestered nitrate and phosphate within the cell were visualized through electron microscopy and explained the reason behind the ability of the isolate to accumulate 1.12 mg of phosphate and 1.3 gm of nitrate per gram of wet weight. Transcriptome analysis proposed the mechanism behind the accumulation of nitrate and phosphate in case of this novel bacterial isolate (MCC 0008). The strain with the sequestered nutrients work as biofertilizer for yield enhancement in case of mung bean while maintaining soil fertility post-cultivation

    Development of Broad Spectrum and Durable Bacterial Blight Resistant Variety through Pyramiding of Four Resistance Genes in Rice

    Get PDF
    Not AvailableBacterial blight (BB) disease caused by Xanthomonas oryzae pv. oryzae is a major biotic constraint on obtaining higher grain yields in rice. Marker-assisted backcross breeding (MABB) was performed by the pyramiding of Xa4, xa5, xa13 and Xa21 resistance genes in the popular variety, Ranidhan. A foreground selection in BC1F1, BC2F1, and BC3F1 progenies detected all the target genes in 12, 7 and 16 progenies by using the closely linked markers from a population size of 426, 410, and 530, respectively. The BB-positive progenies carrying the target genes with a maximal similarity to the recipient parent was backcrossed in each backcross generation. A total of 1784 BC3F2 seeds were obtained from the best BC3F1 progeny. The screening of the BC3F2 progenies for the four target genes resulted in eight plants carrying all the four target genes. A bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight disease. In addition, these pyramided lines were similar to Ranidhan in 16 morpho-quality traits, namely, plant height, filled grains/panicle, panicles/plant, grain length, grain breadth, grain weight, milling, head rice recovery, kernel length after cooking, water uptake, the volume expansion ratio, gel consistency,alkali-spreading value, and the amylose content.Not Availabl
    corecore