1,161 research outputs found
Mixed Models with n>1 and Large Scale Structure constraints
Recent data on CBR anisotropies show a Doppler peak higher than expected in
CDM cosmological models, if the spectral index . However, CDM and LCDM
models with n>1 can hardly be consistent with LSS data. Mixed models, instead,
whose transfer function is naturally steeper because of free--streaming in the
hot component, may become consistent with data if n>1, when Omega_h is large.
This is confirmed by our detailed analysis, extended both to models with a hot
component whose momentum space distribution had a thermal origin (like massive
neutrinos), and to models with a non--cold component arising from heavier
particle decay. In this work we systematically search models which fulfill all
constraints which can be implemented at the linear level. We find that a
stringent linear constraint arises from fitting the extra-power parameter
Gamma. Other significant constraints arise comparing the expected abundances of
galaxy clusters and high-z systems with observational data. Keeping to models
with Gamma \geq 0.13, a suitable part of the space parameter still allows up to
\sim 30% of hot component (it is worth outlining that our stringent criteria
allow only models with 0.10 \mincir Omega_h \mincir 0.16, if n \leq 1). We also
outline that models with such large non--cold component would ease the solution
of the so--called baryon catastrophe in galaxy clusters.Comment: 28 pages + 9 figures, uses elsart.sty, to be published in New
Astronom
Tracking and imaging gamma ray experiment (TIGRE) for 1 to 100 MEV gamma ray astronomy
A large international collaboration from the high energy astrophysics community has proposed the Tracking and Imaging Gamma Ray Experiment (TIGRE) for future space observations. TIGRE will image and perform energy spectroscopy measurements on celestial sources of gamma rays in the energy range from 1 to 100 MeV. This has been a difficult energy range experimentally for gamma ray astronomy but is vital for the future considering the recent exciting measurements below 1 and above 100 MeV. TIGRE is both a double scatter Compton and gamma ray pair telescope with direct imaging of individual gamma ray events.
Multi‐layers of Si strip detectors are used as Compton and pair converters CsI(Tl) scintillation detectors are used as a position sensitive calorimeter. Alternatively, thick GE strip detectors may be used for the calorimeter. The Si detectors are able to track electrons and positrons through successive Si layers and measure their directions and energy losses. Compton and pair events are completely reconstructed allowing each event to be imaged on the sky. TIGRE will provide an order‐of‐magnitude improvement in discrete source sensitivity in the 1 to 100 MeV energy range and determine spectra with excellent energy and excellent angular resolutions. It’s wide field‐of‐view of π sr permits observations of the entire sky for extended periods of time over the life of the mission
Effects of Developmental Deltamethrin Exposure on White Adipose Tissue Gene Expression
Deltamethrin, a type II pyrethroid, is a widely used insecticide. The purpose of this study was to determine whether perinatal deltamethrin exposure altered the expression of adipogenic and lipogenic genes in white adipose tissue (WAT) in adult pups. C57BL/6 pregnant mice were administered 0, 1, or 3 mg/kg of deltamethrin orally every 3 days throughout gestation and lactation. Offspring were weaned on postnatal day 25, and WAT was collected from 5‐month‐old male mice. Perinatal deltamethrin exposure decreased the mRNA expression of adipogenesis‐related transcription factors Pparγ, Cebpα, and lipogenic genes Srebp1c, Acc‐1, Cd36, Lpl, Scd‐1; along with Nrf2 and target genes Nqo1 and Gclc at the 1 mg/kg treatment. Cytokine expression of Fas/Tnf‐R and Cd209e at the 1 mg/kg treatment was significantly decreased, and expression of Tnf, Cd11c, and Fas/Tnf‐R was decreased at the 3 mg/kg treatment. Developmental deltamethrin exposure did not overtly affect body weight or adipose weight, but decreased mRNA expression of specific genes that may potentially disrupt normal adipogenesis and lipid and glucose metabolism if the offspring are challenged by changes in diet or environment
Gene set of nuclear-encoded mitochondrial regulators is enriched for common inherited variation in obesity
There are hints of an altered mitochondrial function in obesity. Nuclear-encoded genes are relevant for mitochondrial function (3 gene sets of known relevant pathways: (1) 16 nuclear regulators of mitochondrial genes, (2) 91 genes for oxidative phosphorylation and (3) 966 nuclear-encoded mitochondrial genes). Gene set enrichment analysis (GSEA) showed no association with type 2 diabetes mellitus in these gene sets. Here we performed a GSEA for the same gene sets for obesity. Genome wide association study (GWAS) data from a case-control approach on 453 extremely obese children and adolescents and 435 lean adult controls were used for GSEA. For independent confirmation, we analyzed 705 obesity GWAS trios (extremely obese child and both biological parents) and a population-based GWAS sample (KORA F4, n = 1,743). A meta-analysis was performed on all three samples. In each sample, the distribution of significance levels between the respective gene set and those of all genes was compared using the leading-edge-fraction-comparison test (cut-offs between the 50(th) and 95(th) percentile of the set of all gene-wise corrected p-values) as implemented in the MAGENTA software. In the case-control sample, significant enrichment of associations with obesity was observed above the 50(th) percentile for the set of the 16 nuclear regulators of mitochondrial genes (p(GSEA,50) = 0.0103). This finding was not confirmed in the trios (p(GSEA,50) = 0.5991), but in KORA (p(GSEA,50) = 0.0398). The meta-analysis again indicated a trend for enrichment (p(MAGENTA,50) = 0.1052, p(MAGENTA,75) = 0.0251). The GSEA revealed that weak association signals for obesity might be enriched in the gene set of 16 nuclear regulators of mitochondrial genes
Being Attractive Brings Advantages: The Case of Parrot Species in Captivity
Background: Parrots are one of the most frequently kept and bred bird orders in captivity. This increases poaching and thus the potential importance of captive populations for rescue programmes managed by zoos and related institutions. Both captive breeding and poaching are selective and may be influenced by the attractiveness of particular species to humans. In this paper, we tested the hypothesis that the size of zoo populations is not only determined by conservation needs, but also by the perceived beauty of individual parrot species assessed by human observers. Methodology/Principal Findings: For the purpose of data collection, we defined four sets of species (40 parrots, 367 parrots, 34 amazons, 17 macaws). Then, we asked 776 human respondents to evaluate parrot pictures of the selected species according to perceived beauty and we analyzed its association with color and morphological characters. Irrespective of the species set, we found a good agreement among the respondents. The preferred species tended to be large, colorful, and long-tailed. Conclusions/Significance: We repeatedly confirmed significant, positive association between the perceived beauty and the size of worldwide zoo population. Moreover, the range size and body size appeared to be significant predictors of zoo population size. In contrast, the effects of other explanatory variables, including the IUCN (International Union for Conservation of Nature) listing, appeared insignificant. Our results may suggest that zoos preferentially keep beautifu
Periodontitis is associated with significant hepatic fibrosis in patients with non-alcoholic fatty liver disease
This work was funded by the Diabetes Research and Wellness Fund. WA is in receipt of an MRC New Investigator Award
Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV
We present limits on anomalous WWZ and WW-gamma couplings from a search for
WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p
-> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron
Collider during the 1992-1995 run. The data sample corresponds to an integrated
luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling
parameters, the 95% CL limits on the CP-conserving couplings are
-0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a
form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also
presented.Comment: 11 pages, 2 figures, 2 table
Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics
We present a quasi-model-independent search for the physics responsible for
electroweak symmetry breaking. We define final states to be studied, and
construct a rule that identifies a set of relevant variables for any particular
final state. A new algorithm ("Sleuth") searches for regions of excess in those
variables and quantifies the significance of any detected excess. After
demonstrating the sensitivity of the method, we apply it to the semi-inclusive
channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV
at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no
evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review
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