1,158 research outputs found
Association of MC1R Variants and host phenotypes with melanoma risk in CDKN2A mutation carriers: a GenoMEL study
<p><b>Background</b> Carrying the cyclin-dependent kinase inhibitor 2A (CDKN2A) germline mutations is associated with a high risk for melanoma. Penetrance of CDKN2A mutations is modified by pigmentation characteristics, nevus phenotypes, and some variants of the melanocortin-1 receptor gene (MC1R), which is known to have a role in the pigmentation process. However, investigation of the associations of both MC1R variants and host phenotypes with melanoma risk has been limited.</p>
<p><b>Methods</b> We included 815 CDKN2A mutation carriers (473 affected, and 342 unaffected, with melanoma) from 186 families from 15 centers in Europe, North America, and Australia who participated in the Melanoma Genetics Consortium. In this family-based study, we assessed the associations of the four most frequent MC1R variants (V60L, V92M, R151C, and R160W) and the number of variants (1, ≥2 variants), alone or jointly with the host phenotypes (hair color, propensity to sunburn, and number of nevi), with melanoma risk in CDKN2A mutation carriers. These associations were estimated and tested using generalized estimating equations. All statistical tests were two-sided.</p>
<p><b>Results</b> Carrying any one of the four most frequent MC1R variants (V60L, V92M, R151C, R160W) in CDKN2A mutation carriers was associated with a statistically significantly increased risk for melanoma across all continents (1.24 × 10−6 ≤ P ≤ .0007). A consistent pattern of increase in melanoma risk was also associated with increase in number of MC1R variants. The risk of melanoma associated with at least two MC1R variants was 2.6-fold higher than the risk associated with only one variant (odds ratio = 5.83 [95% confidence interval = 3.60 to 9.46] vs 2.25 [95% confidence interval = 1.44 to 3.52]; Ptrend = 1.86 × 10−8). The joint analysis of MC1R variants and host phenotypes showed statistically significant associations of melanoma risk, together with MC1R variants (.0001 ≤ P ≤ .04), hair color (.006 ≤ P ≤ .06), and number of nevi (6.9 × 10−6 ≤ P ≤ .02).</p>
<p><b>Conclusion</b> Results show that MC1R variants, hair color, and number of nevi were jointly associated with melanoma risk in CDKN2A mutation carriers. This joint association may have important consequences for risk assessments in familial settings.</p>
Nanolitre real-time PCR detection of bacterial, parasitic, and viral agents from patients with diarrhoea in Nunavut, Canada
Background. Little is known about the microbiology of diarrhoeal disease in Canada's Arctic regions. There are a number of limitations of conventional microbiology testing techniques for diarrhoeal pathogens, and these may be further compromised in the Arctic, given the often long distances for specimen transport. Objective. To develop a novel multiple-target nanolitre real-time reverse transcriptase (RT)-PCR platform to simultaneously test diarrhoeal specimens collected from residents of the Qikiqtani (Baffin Island) Region of Nunavut, Canada, for a wide range of bacterial, parasitic and viral agents. Study design/methods. Diarrhoeal stool samples submitted for bacterial culture to Qikiqtani General Hospital in Nunavut over an 18-month period were tested with a multiple-target nanolitre real-time PCR panel for major diarrhoeal pathogens including 8 bacterial, 6 viral and 2 parasitic targets. Results. Among 86 stool specimens tested by PCR, a total of 50 pathogens were detected with 1 or more pathogens found in 40 (46.5%) stool specimens. The organisms detected comprised 17 Cryptosporidium spp., 5 Clostridium difficile with toxin B, 6 Campylobacter spp., 6 Salmonella spp., 4 astroviruses, 3 noroviruses, 1 rotavirus, 1 Shigella spp. and 1 Giardia spp. The frequency of detection by PCR and bacterial culture was similar for Salmonella spp., but discrepant for Campylobacter spp., as Campylobacter was detected by culture from only 1/86 specimens. Similarly, Cryptosporidium spp. was detected in multiple samples by PCR but was not detected by microscopy or enzyme immunoassay. Conclusions. Cryptosporidium spp., Campylobacter spp. and Clostridium difficile may be relatively common but possibly under-recognised pathogens in this region. Further study is needed to determine the regional epidemiology and clinical significance of these organisms. This method appears to be a useful tool for gastrointestinal pathogen research and may also be helpful for clinical diagnostics and outbreak investigation in remote regions where the yield of routine testing may be compromised
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
Gravitational Waves from Gravitational Collapse
Gravitational wave emission from the gravitational collapse of massive stars
has been studied for more than three decades. Current state of the art
numerical investigations of collapse include those that use progenitors with
realistic angular momentum profiles, properly treat microphysics issues,
account for general relativity, and examine non--axisymmetric effects in three
dimensions. Such simulations predict that gravitational waves from various
phenomena associated with gravitational collapse could be detectable with
advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for
  publication in Living Reviews in Relativity (http://www.livingreviews.org
Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos2Δϕ modulation for all ΣETPb ranges and particle pT
Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-
We report the first observation of the baryonic flavor-changing neutral
current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a
statistical significance of 5.8 Gaussian standard deviations. This measurement
uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV
collected by the CDF II detector at the Tevatron collider. The total and
differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We
find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}.
We also report the first measurement of the differential branching ratio of B_s
-> phi mu+ mu- using 49 signal events. In addition, we report branching ratios
for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let
Characteristic Evolution and Matching
I review the development of numerical evolution codes for general relativity
based upon the characteristic initial value problem. Progress in characteristic
evolution is traced from the early stage of 1D feasibility studies to 2D
axisymmetric codes that accurately simulate the oscillations and gravitational
collapse of relativistic stars and to current 3D codes that provide pieces of a
binary black hole spacetime. Cauchy codes have now been successful at
simulating all aspects of the binary black hole problem inside an artificially
constructed outer boundary. A prime application of characteristic evolution is
to extend such simulations to null infinity where the waveform from the binary
inspiral and merger can be unambiguously computed. This has now been
accomplished by Cauchy-characteristic extraction, where data for the
characteristic evolution is supplied by Cauchy data on an extraction worldtube
inside the artificial outer boundary. The ultimate application of
characteristic evolution is to eliminate the role of this outer boundary by
constructing a global solution via Cauchy-characteristic matching. Progress in
this direction is discussed.Comment: New version to appear in Living Reviews 2012. arXiv admin note:
  updated version of arXiv:gr-qc/050809
Trichomonas vaginalis: Clinical relevance, pathogenicity and diagnosis
Trichomonas vaginalis is the etiological agent of trichomoniasis, the most prevalent non-viral sexually transmitted disease worldwide. Trichomoniasis is a widespread, global health concern and occurring at an increasing rate. Infections of the female genital tract can cause a range of symptoms, including vaginitis and cervicitis, while infections in males are generally asymptomatic. The relatively mild symptoms, and lack of evidence for any serious sequelae, have historically led to this disease being under diagnosed, and under researched. However, growing evidence that T. vaginalis infection is associated with other disease states with high morbidity in both men and women has increased the efforts to diagnose and treat patients harboring this parasite. The pathology of trichomoniasis results from damage to the host epithelia, caused by a variety of processes during infection and recent work has highlighted the complex interactions between the parasite and host, commensal microbiome and accompanying symbionts. The commercial release of a number of nucleic acid amplification tests (NAATs) has added to the available diagnostic options. Immunoassay based Point of Care testing is currently available, and a recent initial evaluation of a NAAT Point of Care system has given promising results, which would enable testing and treatment in a single visit
Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb−1 of pp collisions at √s=13 TeV with the ATLAS detector
A search for heavy neutral Higgs bosons and Z′ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb −1 from proton-proton collisions at s=13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to τ + τ − with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for Z′ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude tan β  >  1.0 for m A = 0.25 TeV and tan β  >  42 for m A = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, Z SSM ′ with m Z′ <  2.42 TeV is excluded at 95% confidence level, while Z NU ′ with m Z ′ <  2.25 TeV is excluded for the non-universal G(221) model that exhibits enhanced couplings to third-generation fermions
Operation and performance of the ATLAS Tile Calorimeter in Run 1
The Tile Calorimeter is the hadron calorimeter covering the central region of the ATLAS experiment at the Large Hadron Collider. Approximately 10,000 photomultipliers collect light from scintillating tiles acting as the active material sandwiched between slabs of steel absorber. This paper gives an overview of the calorimeter’s performance during the years 2008–2012 using cosmic-ray muon events and proton–proton collision data at centre-of-mass energies of 7 and 8TeV with a total integrated luminosity of nearly 30 fb−1. The signal reconstruction methods, calibration systems as well as the detector operation status are presented. The energy and time calibration methods performed excellently, resulting in good stability of the calorimeter response under varying conditions during the LHC Run 1. Finally, the Tile Calorimeter response to isolated muons and hadrons as well as to jets from proton–proton collisions is presented. The results demonstrate excellent performance in accord with specifications mentioned in the Technical Design Report
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