1,332 research outputs found

    Mass-Galaxy offsets in Abell 3827, 2218 and 1689: intrinsic properties or line-of-sight substructures?

    Full text link
    We have made mass maps of three strong-lensing clusters, Abell 3827, Abell 2218 and Abell 1689, in order to test for mass-light offsets. The technique used is GRALE, which enables lens reconstruction with minimal assumptions, and specifically with no information about the cluster light being given. In the first two of these clusters, we find local mass peaks in the central regions that are displaced from the nearby galaxies by a few to several kpc. These offsets {\em could\/} be due to line of sight structure unrelated to the clusters, but that is very unlikely, given the typical levels of chance line-of-sight coincidences in ΛCDM\Lambda CDM simulations --- for Abell 3827 and Abell 2218 the offsets appear to be intrinsic. In the case of Abell 1689, we see no significant offsets in the central region, but we do detect a possible line of sight structure: it appears only when sources at z\ga 3 are used for reconstructing the mass. We discuss possible origins of the mass-galaxy offsets in Abell 3827 and Abell 2218: these include pure gravitational effects like dynamical friction, but also non-standard mechanisms like self-interacting dark-matter.Comment: 14 pages, 9 figures; Accepted for publication in MNRA

    Kernel estimation of residual extropy function under α-mixing dependence condition

    Get PDF
    As in the context of introducing the concept of residual entropy in the literature, Qiu and Jia (2018b) introduced the concept, residual extropy to measure the residual uncertainty of a random variable. In this work, we propose a nonparametric estimator for the residual extropy, where the observations under consideration are exhibiting α-mixing (strong mixing) dependence condition. Asymptotic properties of the estimator is derived under suitable regular conditions. A Monte Carlo simulation study is carried out to evaluate the performance of the estimator using the mean squared errors

    Quantifying substructures in {\it Hubble Frontier Field} clusters: comparison with ΛCDM\Lambda CDM simulations

    Full text link
    The Hubble Frontier Fields (HFF) are six clusters of galaxies, all showing indications of recent mergers, which have recently been observed for lensed images. As such they are the natural laboratories to study the merging history of galaxy clusters. In this work, we explore the 2D power spectrum of the mass distribution PM(k)P_{\rm M}(k) as a measure of substructure. We compare PM(k)P_{\rm M}(k) of these clusters (obtained using strong gravitational lensing) to that of Λ\LambdaCDM simulated clusters of similar mass. To compute lensing PM(k)P_{\rm M}(k), we produced free-form lensing mass reconstructions of HFF clusters, without any light traces mass (LTM) assumption. The inferred power at small scales tends to be larger if (i)~the cluster is at lower redshift, and/or (ii)~there are deeper observations and hence more lensed images. In contrast, lens reconstructions assuming LTM show higher power at small scales even with fewer lensed images; it appears the small scale power in the LTM reconstructions is dominated by light information, rather than the lensing data. The average lensing derived PM(k)P_{\rm M}(k) shows lower power at small scales as compared to that of simulated clusters at redshift zero, both dark-matter only and hydrodynamical. The possible reasons are: (i)~the available strong lensing data are limited in their effective spatial resolution on the mass distribution, (ii)~HFF clusters have yet to build the small scale power they would have at z∼0z\sim 0, or (iii)~simulations are somehow overestimating the small scale power.Comment: 13 pages, 10 figures, 1 table; Accepted for publication in MNRA

    Protection by 20-5,14-HEDGE Against Surgically-Induced Ischemia Reperfusion Lung Injury in Rats

    Get PDF
    Background We previously reported that the cytochrome P450 product 20-hydroxyeicosatetraenoic acid has prosurvival effects in pulmonary artery endothelial cells and ex vivo pulmonary arteries. We tested the potential of a 20-hydroxyeicosatetraenoic acid analog N-[20-hydroxyeicosa-5(Z),14(Z)-dienoyl]glycine (20-5,14-HEDGE) to protect against lung ischemic reperfusion injury in rats. Furthermore, we examined activation of innate immune system components, high mobility group box 1 (HMGB1) and toll-like receptor 4 (TLR4), in this model as well as the effect of 20-5,14-HEDGE on this signaling pathway. Methods Sprague-Dawley rats treated with 20-5,14-HEDGE or vehicle were subjected to surgically induced, unilateral lung ischemia for 60 minutes followed by reperfusion for 2 hours in vivo. Injury was assessed histologically by hematoxylin and eosin, and with identification of myeloperoxidase immunohistochemically. The HMGB1 and TLR4 proteins were identified by Western blot. Caspase 3 activity or 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole, incorporation were used to measure apoptosis and cell survival. Results The ischemia reperfusion injury evoked atelectasis and hemorrhage, an influx of polymorphonuclear cells, and increased TLR4 and HMGB1 expression. Caspase 3 activity was increased, and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide incorporation was decreased. The 20-5,14-HEDGE protected against each of these endpoints, including infiltration of polymorphonuclear cells, with no changes in caspase 3 activity in other organs. Conclusions Lung ischemia reperfusion produces apoptosis and activation of the innate immune system including HMGB1 and TLR4 within 2 hours of reperfusion. Treatment with 20-5,14-HEDGE decreases activation of this response system, and salvages lung tissue

    Hypoxia Preconditioning Increases Survival and Decreases Expression of Toll-like Receptor 4 in Pulmonary Artery Endothelial Cells Exposed to Lipopolysaccharide

    Get PDF
    Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll-like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with LPS. TLR4 antagonist TAK-242 was used to probe the role played by TLR4 receptors in cell survival. Cell apoptosis and survival were measured by caspase 3 activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) incorporation. TLR4 expression and tumor necrosis factor α (TNF-α) production were also determined. LPS increased caspase 3 activity in a TAK-242-sensitive manner and decreased MTT incorporation. Apoptosis was decreased in PAECs preconditioned with hypoxia prior to LPS exposure. LPS increased TNF-α production, and hypoxic preconditioning blunted it. Hypoxic preconditioning reduced LPS-induced TLR4 messenger RNA and TLR4 protein. TAK-242 decreased to baseline the LPS-stimulated expression of TLR4 messenger RNA regardless of environmental conditions. In contrast, LPS followed by hypoxia substantially increased apoptosis and cell death. In conclusion, protection from LPS-stimulated PAEC apoptosis by hypoxic preconditioning is attributable in part to reduction in TLR4 expression. If these signaling pathways apply to septic patients, they may account for differing sensitivities of individuals to acute lung injury depending on oxygen tensions in PAECs in vivo

    AN INNOVATIVE METHOD DEVELOPMENT AND FORCED DEGRADATION STUDIES FOR SIMULTANEOUS ESTIMATION OF SOFOSBUVIR AND LEDIPASVIR BY RP HPLC

    Get PDF
    Objective: To develop an innovative, rapid, simple, cost-effective, stability indicating reverse phase-high performance liquid chromatography (RP-HPLC) method for simultaneous estimation of ledipasvir (LP) and sofosbuvir (SB) in combination pill dosage form. Methods: The method was developed using C8 column, 250 mm x 4.6 mm, 5 mm using mobile section comprising of 0.1% (v/v) orthophosphoric acid buffer at pH 2.2 and acetonitrile in the ratio of 45:55 that was pumped through the column at a flow rate of 0.8 ml/min. Temperature was maintained at 30 °C, the effluents were monitored at 260 nm with the help of usage of PDA detector. Results: The retention time of LP and SB were found to be 2.246 min and 3.502 min. The approach was found to be linear with the variety of 9-36 µg/ml and 40-240 μg/ml for LP and SB respectively, the assay of estimated compounds were found to be 99.65% and 99.73% w/v for LP and SB respectively. Conclusion: The pressured samples changed into analyzed and this proposed a technique turned into determined to be particular and stability indicating as no interfering peaks of decay compound and excipients were observed. Hence, the approach was easy and economical that may be efficiently applied for simultaneous estimation of both LP and SB in bulk and combination tablet system

    EIMERIOSIS IN POULTRY OF RAWALPINDI/ISLAMABAD AREA

    Get PDF
    This study was designed to determine the prevalence of eimeriosis in poultry and identify potential risk factors for its spread in Rawalpindi/Islamabad area of Pakistan. Of 359 gut samples (suspected for harbouring eimeriosis) examined, 258 (71.86%) were found infected. Four species of Eimeria (E. maxima, 34.10%, E. tenella, 30.62%, E. mitis, 13.95% and E. necatrix, 7.75%) were recorded. The prevalence of eimeriosis was highest in the month of September (89.74%), while lowest during June (28.57%). The disease was more common at the farms where the litter was wet and not managed properly

    Toxicity of conventonal insecticides to fourth instar larvae of tobaccocaterpillar, Spodoptera litura (Fab.) in different generations

    Get PDF
    Studies on development of resistance in tobacco caterpillar against some insecticides were carried out in the laboratory, Division of Entomology, Udheywalla, Jammu. The differential susceptibility level of parental and susceptible strains of tobacco caterpillar to conventional insecticides revealed that the level of susceptibility in 4th instar larvae of this insect has decreased considerably in parental strain as compared to recommended concentrations of insecticides. The highest resistance factor of 9.33 was observed with monocrotophos whereas malathion encountered lowest resistance factor of 1.50. Comparison of the LC50 values obtained in succeeding generations with the 1st generation in 4th instar larvae of S. litura revealed that the resistance developed in an increasing order in all the six generations. The resistance ratio in the 6th generation as compared to the 1st generation was 3.97- fold in endosulfan, 3.11 in malathion and 3.45 in carbaryl

    Plant Biomass Productivity Under Abiotic Stresses in SAT Agriculture

    Get PDF
    The semi-arid tropics (SAT) include parts of 48 countries in the developing world: in most of India, locations in south east Asia, a swathe across sub-Saharan Africa, much of southern and eastern Africa, and a few locations in Latin America (Fig 1). Semi-arid tropical regions are characterized by unpredictable weather, long dry seasons, inconsistent rainfall, and soils that are poor in nutrients. Sorghum, millet, cowpea, chickpea, pigeonpea and groundnut are the vital crops that feed the poor people living in the SAT. Environmental stresses represent the most limiting factors for agricultural productivity. Apart from biotic stresses caused by plant pathogens, there are a number of abiotic stresses such as extremes temperatures, drought, salinity and radiation which all have detrimental effects on plant growth and yield, especially when several occur together (Mittler 2006)
    • …
    corecore