49 research outputs found
Cooling of Dark-Matter Admixed Neutron Stars with density-dependent Equation of State
We propose a dark-matter (DM) admixed density-dependent equation of state
where the fermionic DM interacts with the nucleons via Higgs portal. Presence
of DM can hardly influence the particle distribution inside neutron star (NS)
but can significantly affect the structure as well as equation of state (EOS)
of NS. Introduction of DM inside NS softens the equation of state. We explored
the effect of variation of DM mass and DM Fermi momentum on the NS EOS.
Moreover, DM-Higgs coupling is constrained using dark matter direct detection
experiments. Then, we studied cooling of normal NSs using APR and DD2 EOSs and
DM admixed NSs using dark-matter modified DD2 with varying DM mass and Fermi
momentum. We have done our analysis by considering different NS masses. Also DM
mass and DM Fermi momentum are varied for fixed NS mass and DM-Higgs coupling.
We calculated the variations of luminosity and temperature of NS with time for
all EOSs considered in our work and then compared our calculations with the
observed astronomical cooling data of pulsars namely Cas A, RX J0822-43, 1E
1207-52, RX J0002+62, XMMU J17328, PSR B1706-44, Vela, PSR B2334+61, PSR
B0656+14, Geminga, PSR B1055-52 and RX J0720.4-3125. It is found that APR EOS
agrees well with the pulsar data for lighter and medium mass NSs but cooling is
very fast for heavier NS. For DM admixed DD2 EOS, it is found that for all
considered NS masses, all chosen DM masses and Fermi momenta agree well with
the observational data of PSR B0656+14, Geminga, Vela, PSR B1706-44 and PSR
B2334+61. Cooling becomes faster as compared to normal NSs in case of
increasing DM mass and Fermi momenta. It is infered from the calculations that
if low mass super cold NSs are observed in future that may support the fact
that heavier WIMP can be present inside neutron stars.Comment: 24 Pages, 15 Figures and 2 Tables. Version accepted in The European
Physical Journal
Eccentricity-induced systematic error on parametrized tests of general relativity: hierarchical Bayesian inference applied to a binary black hole population
One approach to testing general relativity (GR) introduces free parameters in
the post-Newtonian (PN) expansion of the gravitational-wave (GW) phase. If
systematic errors on these testing GR (TGR) parameters exceed the statistical
errors, this may signal a false violation of GR. Here, we consider systematic
errors produced by unmodeled binary eccentricity. Since the eccentricity of GW
events in ground-based detectors is expected to be small or negligible, the use
of quasicircular waveform models for testing GR may be safe when analyzing a
small number of events. However, as the catalog size of GW detections
increases, more stringent bounds on GR deviations can be placed by combining
information from multiple events. In that case, even small systematic biases
may become significant. We apply the approach of hierarchical Bayesian
inference to model the posterior probability distributions of the TGR
parameters inferred from a population of eccentric binary black holes (BBHs).
We assume each TGR parameter value varies across the BBH population according
to a Gaussian distribution. We compute the posterior distributions for these
Gaussian hyperparameters. This is done for LIGO and Cosmic Explorer (CE). We
find that systematic biases from unmodeled eccentricity can signal false GR
violations for both detectors when considering constraints set by a catalog of
events. We also compute the projected bounds on the TGR parameters when
eccentricity is included as a parameter in the waveform model. We find that the
first four dimensionless TGR deformation parameters can be bounded at
confidence to for LIGO and for CE [where ]. In comparison to the circular orbit
case, the combined bounds on the TGR parameters worsen by a modest factor of
when eccentricity is included in the waveform.Comment: 23 pages, 9 figures, 1 tabl
Propagation of Himalayan maple (Acer caesium Wall.) through seed and softwood cuttings
Propagation of Himalayan maple (Acer caesium Wall.) through seed and softwood cuttings was investigated to standardize nursery techniques for mass production of the species. The seedlings were raised from viable seeds in different containers filled with different combinations of growing media. Vegetative propagation of softwoodcuttings was carried out by treating with different combinations of IBA and Willow leachate of different durations. The statistical analysis revealed the differential behaviour of various nursery stocks with respect to survival, growth and biomass. The growing media soil:sand:vermicompost (2:1:2) and container (root trainer 300 cc) showed maximum germination (61.00%), seedlings height (35.17 cm), collar diameter (5.07 cm), shoot:root ratio (1.24) and survival percentage (76.33%). Conversely, the cuttings treated with IBA @ 8000 ppm showed maximum sprouting (74.50%), rooting (66.75%), length of longest root (14.65 cm), no. of roots per cutting (33.00%), shoot length (13.90 cm) and survival percentage (41.50%). Hence, the seeds of the species should be grown in Rot trainer of 300 cc having soil:sand:vermicompost (2:1:2) to get good quality planting materials. However, the softwood cuttings should be given treatments with IBA @ 8000 ppm for mass production of plants vegetatively
Checkpoint Blockade Rescues the Repressive Effect of Histone Deacetylases Inhibitors on γδ T Cell Function
Histone deacetylases (HDAC) are one of the key epigenetic modifiers that control chromatin accessibility and gene expression. Their role in tumorigenesis is well established and HDAC inhibitors have emerged as an effective treatment modality. HDAC inhibitors have been investigated for their specific antitumor activities and also clinically evaluated in treatment of various malignancies. In the present study, we have investigated the effect of HDAC inhibitors on the effector functions of human γδ T cells. HDAC inhibitors inhibit the antigen-specific proliferative response of γδ T cells and cell cycle progression. In antigen-activated γδ T cells, the expression of transcription factors (Eomes and Tbet) and effector molecules (perforin and granzyme B) were decreased upon treatment with HDAC inhibitors. Treatment with HDAC inhibitors attenuated the antitumor cytotoxic potential of γδ T cells, which correlated with the enhanced expression of immune checkpoints programmed death-1 (PD-1) and programmed death ligand-1 in γδ T cells. Interestingly, PD-1 blockade improves the antitumor effector functions of HDAC inhibitor-treated γδ T cells, which is reflected in the increased expression of Granzyme B and Lamp-1. This study provides a rationale for designing HDAC inhibitor and immune check point blockade as a combinatorial treatment modality for cancer
Smoking behaviour among young doctors of a tertiary care hospital in North India
Background:Tobacco use is one of the biggest public health threats the world has ever faced. There are more than one billion smokers in the world. Almost half of the world's children breathe air polluted by tobacco. Aim of current study was to study the smoking trends among young doctors in a tertiary care institute in north India.Methods:A descriptive observational cross-sectional epidemiological study was conducted among 250 doctors of a tertiary care Hospital in Jammu & Kashmir (Sheri Kashmir Institute of Medical Sciences, SKIMS) during the two months of February-March, 2014. The predesigned tool adopted during data collection was a questionnaire that was developed at the institute with the assistance from the faculty members and other experts.Results:Among 250 participants, (20%) were smokers; among smokers, (76%) were regular smokers and (24%) were occasional smokers. Majority of smokers were in the age group of 21-30 years (80%) & started smoking between 11-20 years (70%). All of them were male (100%). No significant difference was observed among urban and rural students. Among smokers, majority (60%) was in the practice of smoking for last 6 months to 1 year and 26% smoked for <6 months; & (14%) smoked for more than 5 years .It was found more than half of the responding (60%) students used to smoke 5-9 cigarettes per day; 14% is <5 and 26% consumed 10 or more per day .Among smokers, peer pressure was found in 80% cases. (χ2 = 107, P <0.001). Among smokers, almost 20% had other addiction and among non-smokers only 5% had .Effect of parental smoking was significantly higher in smokers than non-smoker (χ2 = 66.2, P <0.001) .It was seen that peer pressure was the most important risk factor (60%) of initiation of smoking habit followed by parental influence (20%). Majority (78.4%) had no intention to quit in the next 6 months. Lack of Incentive (36.36%) and Addiction (27.27%) were the main reasons for not quitting.Conclusion:We need to create more awareness regarding hazards of smoking in general population especially in medical students, and afterwards provide psychological and pharmacological support for those who intend to quit, as medical students can themselves become a tool to fight this hazard at all levels.
DNA barcoding: a way forward to obtain deep insights about the realistic diversity of living organisms
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Early immune suppression leads to uncontrolled mite proliferation and potent host inflammatory responses in a porcine model of crusted versus ordinary scabies
peer-reviewedScabies is a neglected tropical disease of global significance. Our understanding of hostparasite interactions has been limited, particularly in crusted scabies (CS), a severe clinical
manifestation involving hyper-infestation of Sarcoptes scabiei mites. Susceptibility to CS
may be associated with immunosuppressive conditions but CS has also been seen in cases
with no identifiable risk factor or immune deficit. Due to ethical and logistical difficulties with
undertaking research on clinical patients with CS, we adopted a porcine model which parallels human clinical manifestations. Transcriptomic analysis using microarrays was used to
explore scabies pathogenesis, and to identify early events differentiating pigs with ordinary
(OS) and crusted scabies. Pigs with OS (n = 4), CS (n = 4) and non-infested controls (n = 4)
were compared at pre-infestation, weeks 1, 2, 4 and 8 post-infestation. In CS relative to OS,
there were numerous differentially expressed genes including pro-inflammatory cytokines
(IL17A, IL8, IL19, IL20 and OSM) and chemokines involved in immune cell activation and
recruitment (CCL20, CCL27 and CXCL6). The influence of genes associated with immune
regulation (CD274/PD-L1 and IL27), immune signalling (TLR2, TLR8) and antigen presentation (RFX5, HLA-5 and HLA-DOB) were highlighted in the early host response to CS. We
observed similarities with gene expression profiles associated with psoriasis and atopic dermatitis and confirmed previous observations of Th2/17 pronounced responses in CS. This is
the first comprehensive study describing transcriptional changes associated with the development of CS and significantly, the distinction between OS and CS. This provides a basis
for clinical follow-up studies, potentially identifying new control strategies for this severely
debilitating diseaseNational Health and Medical Research Counci