934 research outputs found

    Gamma rays and neutrinos from dark matter annihilation in galaxy clusters

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    The γ\gamma-ray and neutrino emissions from dark matter (DM) annihilation in galaxy clusters are studied. After about one year operation of Fermi-LAT, several nearby clusters are reported with stringent upper limits of GeV γ\gamma-ray emission. We use the Fermi-LAT upper limits of these clusters to constrain the DM model parameters. We find that the DM model distributed with substructures predicted in cold DM (CDM) scenario is strongly constrained by Fermi-LAT γ\gamma-ray data. Especially for the leptonic annihilation scenario which may account for the e±e^{\pm} excesses discovered by PAMELA/Fermi-LAT/HESS, the constraint on the minimum mass of substructures is of the level 102−10310^2-10^3 M⊙_{\odot}, which is much larger than that expected in CDM picture, but is consistent with a warm DM scenario. We further investigate the sensitivity of neutrino detections of the clusters by IceCube. It is found that neutrino detection is much more difficult than γ\gamma-rays. Only for very heavy DM (∼10\sim 10 TeV) together with a considerable branching ratio to line neutrinos the neutrino sensitivity is comparable with that of γ\gamma-rays.Comment: 21 pages, 8 figures and 1 table; extended discussion about the uncertainties of concentration and subhalo models, figures replotted for better read; references updated; accepted for publication by Phys. Rev.

    The era of multigene panels comes? The clinical utility of Oncotype DX and MammaPrint

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    The AJCC Cancer Staging Manual, eighth edition published in late 2016, will become the new global guideline for cancer diagnosis and treatment from January 1, 2018. The new edition for the tumor staging system has numerous updates, including building up the prognostic stage group of tumors for the first time and adding a large number of non-anatomical factors into the prognostic evaluation. Oncotype DX and MammaPrint are two of the genomic predictors that will be part of routine clinical practice in the future. Numerous studies have proved the clinical utility of multigene panels in predicting clinical outcome and treatment response. Here we present our review of the studies on these multigene panels and their application to breast cancer

    28 Gb/s direct modulation heterogeneously integrated C-band InP/SOI DFB laser

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    We demonstrate direct modulation of a heterogeneously integrated C-band DFB laser on SOI at 28 Gb/s with a 2 dB extinction ratio. This is the highest direct modulation bitrate so far reported for a membrane laser coupled to an SOI waveguide. The laser operates single mode with 6 mW output power at 100 mA bias current. The 3 dB modulation bandwidth is 15 GHz. Transmission experiments using a 2 km non zero dispersion shifted single mode fiber were performed at 28 Gb/s bitrate using a 2(7)-1 NRZ-PRBS pattern resulting in a 1 dB power penalty. (C) 2015 Optical Society of Americ

    Atmospheric mercury inputs in montane soils increase with elevation: evidence from mercury isotope signatures

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    The influence of topography on the biogeochemical cycle of mercury (Hg) has received relatively little attention. Here, we report the measurement of Hg species and their corresponding isotope composition in soil sampled along an elevational gradient transect on Mt. Leigong in subtropical southwestern China. The data are used to explain orography-related effects on the fate and behaviour of Hg species in montane environments. The total- and methyl-Hg concentrations in topsoil samples show a positive correlation with elevation. However, a negative elevation dependence was observed in the mass- ependent fractionation (MDF) and mass-independent fractionation (MIF) signatures of Hg isotopes. Both a MIF (D199Hg) binary mixing approach and the traditional inert element method indicate that the content of Hg derived from the atmosphere distinctly increases with altitude.publishedVersio

    Genetic polymorphisms of TLR3 are associated with Nasopharyngeal carcinoma risk in Cantonese population

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    <p>Abstract</p> <p>Background</p> <p>Nasopharyngeal carcinoma is endemic in Southern China, displays a strong relationship with genetic susceptibility and associates with Epstein-Barr virus infection. Toll-like receptor 3 (TLR3) plays an important role in the antivirus response. Therefore, we examined the association between <it>TLR3 </it>gene polymorphisms and NPC susceptibility.</p> <p>Methods</p> <p>We performed a case-control study of 434 NPC cases and 512 healthy controls matched on age, sex and residence. Both cases and controls are of Cantonese origin from Southern China. Genetic variants in <it>TLR3 </it>were determined by polymerase chain reaction (PCR)-based DNA direct sequencing and four SNPs were genotyped in all samples.</p> <p>Results</p> <p>Our results showed that allele C for SNP 829A/C increased NPC risk significantly ((p = 0.0068, OR = 1.49, 95%CI:1.10–2.00). When adjusted for age, gender and VCA-IgA antibody titers, the NPC risk was reduced significantly among individuals who carried the haplotype "ATCT" compared to those who carried the most common haplotype "ACCT" (p = 0.0054, OR = 0.028; 95% CI (0.002–0.341).</p> <p>Conclusion</p> <p>The <it>TLR3 </it>polymorphisms may be relevant to NPC susceptibility in the Cantonese population, although the reduction in NPC risk is modest and the biological mechanism of the observed association merits further investigation.</p

    Visual Reconstruction and Feature Analysis of the Three-Dimensional Surface of Earthworm

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    This paper demonstrates a method for visual reconstruction and feature analysis of the three-dimensional surface of earthworm in CATIA (Computer Aided Three Dimensional Interactive Application) and IDL (Interactive Data Language). The earthworm, with a relatively simple surface morphology and good capability in reducing soil adhesion and resistance, was selected to study the feasible methods in the visual reconstruction and feature analysis of the three-dimensional surface of living things. The digital measurements of surfaces of the earthworm were carried out using a three-dimensional laser scanner. Point clouds, the scanning digital data of the surface of the earthworm, were processed by screening unwanted data, reconstructing surface and analysing feature in CATIA. In order to get more detail information about the point clouds, IDL, which integrates a powerful, array-oriented language with numerous mathematical analysis and graphical display techniques, was adopted for the visual reconstruction and feature analysis of three- dimensional surface of the earthworm. Importing of point clouds and reconstruction of the surface of earthworm were conducted in CATIA. Analysis feature of the scanning data and reconstructing surface were carried out in IDL, which provides a high level of flexibility to access, analyse and visualize the data using different methods. Polynomial regression equation of the surface of earthworm in the longitudinal plane was derived. In addition, point clouds were more easily displayed and analysed by resizing, rotating and zooming in IDL. Methods and results presented in this paper prove to be potentially useful for analyzing the feature of biological prototype, optimizing the mathematical model and affording deformable physical model to bionic engineering, those works would have great implications to the research of biological coupling theory and technological creation in bionic engineering. Keywords: Visual Reconstruction; Feature Analysis; Three-Dimensional Surface; Earthworm; CATIA; ID

    43 Gb/s NRZ-OOK direct modulation of a heterogeneously integrated InP/Si DFB laser

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    We discuss howInP membrane laser diodes, heterogeneously integrated on SOI can be designed for high speed operation and how one can take advantage of the heterogeneous integration. This is illustrated with several static and dynamic characteristics of fabricated 1550 nm lasers. We show nonreturn to zero on-off keying at 43 Gb/s and report link experiments over 2 km
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