1,508 research outputs found
Brominated flame retardants in Canadian chicken egg yolks
Chicken eggs categorised as conventional, omega-3 enriched, free range and organic were collected at grading stations in three regions of Canada between 2005 and 2006. Free run eggs, which were only available for collection from two regions, were also sampled during this time frame. Egg yolks from each of these egg types (n = 162) were analysed to determine brominated flame retardant levels, specifically polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). PBDEs were detected in 100% of the 162 samples tested, while HBCD was observed in 85% of the egg yolks. Total PBDE concentrations in egg yolks ranged from 0.018 to 20.9 ng g−1 lipid (median = 3.03 ng g−1 lipid), with PBDE 209 identified as being the major contributor to ΣPBDE concentrations. In addition to PBDE 209, PBDE 99, 47, 100, 183 and 153 were important contributors to ΣPBDE concentrations. Total HBCD concentrations ranged from below the limit of detection to a maximum concentration of 71.9 ng g−1 lipid (median = 0.053 ng g−1 lipid). The α-isomer was the dominant contributor to ΣHBCD levels in Canadian egg yolks and was the most frequently detected HBCD isomer. ΣPBDE levels exhibited large differences in variability between combinations of region and type. ΣHBCD concentrations were not significantly different among regions, although differences were observed between the different types of egg yolks analysed in the present study
Quasi-Normal Modes of Stars and Black Holes
Perturbations of stars and black holes have been one of the main topics of
relativistic astrophysics for the last few decades. They are of particular
importance today, because of their relevance to gravitational wave astronomy.
In this review we present the theory of quasi-normal modes of compact objects
from both the mathematical and astrophysical points of view. The discussion
includes perturbations of black holes (Schwarzschild, Reissner-Nordstr\"om,
Kerr and Kerr-Newman) and relativistic stars (non-rotating and
slowly-rotating). The properties of the various families of quasi-normal modes
are described, and numerical techniques for calculating quasi-normal modes
reviewed. The successes, as well as the limits, of perturbation theory are
presented, and its role in the emerging era of numerical relativity and
supercomputers is discussed.Comment: 74 pages, 7 figures, Review article for "Living Reviews in
Relativity
Obstetric and perinatal factors as predictors of child behaviour at 5 years
Objective To identify whether obstetric and perinatal factors are independent predictors of child behaviour at 5 years. Methodology The Mater University Study of Pregnancy (MUSP) is a prospective cohort study of 8556 mothers enrolled in early pregnancy. The relationship of obstetric and perinatal factors, maternal lifestyle, age and gender of the child, and social disadvantage were examined as predictors of child behaviour in 5005 children completing a modified child behaviour checklist at 5 years. This checklist contained three independent groups of behaviour: externalizng, internalizing and SAT (social, attentional and thought problems). Results In the initial analysis a limited number of associations were present. After adjusting for measures of social disadvantage, only number of antenatal admissions was associated with child behaviour in all three scales, while maternal cigarette smoking in pregnancy and male gender were associated with externalising and SAT behaviours. Conclusions Most common epidemiologic obstetric and perinatal risk factors were not independent predictors of behaviour problems in children at 5 years
Important prognostic factors for the long-term survival of lung cancer subjects in Taiwan
<p>Abstract</p> <p>Background</p> <p>This study used a large-scale cancer database in determination of prognostic factors for the survival of lung cancer subjects in Taiwan.</p> <p>Methods</p> <p>Total of 24,910 subjects diagnosed with lung cancer was analysed. Survival estimates by Kaplan-Meier methods. Cox proportional-hazards model estimated the death risk (hazard ratio (HR)) for various prognostic factors.</p> <p>Results</p> <p>The prognostic indicators associated with a higher risk of lung cancer deaths are male gender (males versus females; HR = 1.07, 95% confidence intervals (CI): 1.03–1.11), males diagnosed in later periods (shown in 1991–1994 versus 1987–1990; HR = 1.13), older age at diagnosis, large cell carcinoma (LCC)/small cell carcinoma (SCC), and supportive care therapy over chemotherapy. The overall 5-year survival rate for lung cancer death was significantly poorer for males (21.3%) than females (23.6%). Subjects with squamous cell carcinoma (SQCC) and treatment by surgical resection alone had better prognosis. We find surgical resections to markedly increase 5-year survival rate from LCC, decreased risk of death from LCC, and no improved survival from SCC.</p> <p>Conclusion</p> <p>Gender and clinical characteristics (i.e. diagnostic period, diagnostic age, histological type and treatment modality) play important roles in determining lung cancer survival.</p
Sequence Variations of Latent Membrane Protein 2A in Epstein-Barr Virus-Associated Gastric Carcinomas from Guangzhou, Southern China
Latent membrane protein 2A (LMP2A), expressed in most Epstein-Barr virus (EBV)-associated malignancies, has been demonstrated to be responsible for the maintenance of latent infection and epithelial cell transformation. Besides, it could also act as the target for a CTL-based therapy for EBV-associated malignancies. In the present study, sequence variations of LMP2A in EBV-associated gastric carcinoma (EBVaGC) and healthy EBV carriers from Guangzhou, southern China, where nasopharyngeal carcinoma (NPC) is endemic, were investigated. Widespread sequence variations in the LMP2A gene were found, with no sequence identical to the B95.8 prototype. No consistent mutation was detected in all isolates. The immunoreceptor tyrosine-based activation motif (ITAM) and PY motifs in the amino terminus of LMP2A were strictly conserved, suggesting their important roles in virus infection; while 8 of the 17 identified CTL epitopes in the transmembrane region of LMP2A were affected by at least one point mutation, which may implicate that the effect of LMP2A polymorphisms should be considered when LMP2A-targeted immunotherapy is conducted. The polymorphisms of LMP2A in EBVaGC in gastric remnant carcinoma (GRC) were for the first time investigated in the world. The LMP2A sequence variations in EBVaGC in GRC were somewhat different from those in EBVaGC in conventional gastric carcinoma. The sequence variations of LMP2A in EBVaGC were similar to those in throat washing of healthy EBV carriers, indicating that these variations are due to geographic-associated polymorphisms rather than EBVaGC-associated mutations. This, to our best knowledge, is the first detailed investigation of LMP2A polymorphisms in EBVaGC in Guangzhou, southern China, where NPC is endemic
Effect of Schistosomiasis and Soil-Transmitted Helminth Infections on Physical Fitness of School Children in Côte d'Ivoire
The burden of parasitic worm infections is considerable, particularly in developing countries. It is acknowledged that parasitic worm infections negatively impact on children's school performance and physical development. A deeper understanding of these linkages is important for updating burden of disease measures. We investigated the relationship between worm infection status and physical fitness of 156 school children from Côte d'Ivoire and controlled for potential confounding of Plasmodium infection (the causative agent of malaria) and environmental parameters (temperature and humidity). Children were diagnosed for parasitic worm and Plasmodium infections, examined by a physician, and participated in a 20 m shuttle run test to assess their maximal oxygen uptake (VO2 max) as a proxy for physical fitness. Most of the children had parasitic worms and a Plasmodium infection. Nevertheless, their physical fitness was excellent (average VO2 max: 52.7 ml kg−1 min−1). The level of VO2 max was only influenced by sex and age, but not by parasitic worms and Plasmodium infections. In future studies, the dynamics of children's physical performance should be assessed before and after control interventions, including the assessment of blood hemoglobin, hematocrit, and nutritional indicators to determine whether physical fitness in worm- and Plasmodium-infected individuals can be further improved
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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