10,598 research outputs found

    Next-to-leading order QCD effects in associated charged Higgs and W boson production in the MSSM at the CERN Large Hadron Collider

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    We present the calculations of the next-to-leading order (NLO) QCD corrections to the inclusive total cross sections for the associated production of the W±H∓W^{\pm}H^{\mp} through bbˉb\bar{b} annihilation in the Minimal Supersymmetric Standard Model at the CERN Large Hadron Collider. The NLO QCD corrections can either enhance or reduce the total cross sections, but they generally efficiently reduce the dependence of the total cross sections on the renormalization/factorization scale. The magnitude of the NLO QCD corrections is about 10% in most of the parameter space and can reach 15% in some parameter regions. We also show the Monte Carlo simulation results for the 2j+τjet+̸pT2j+\tau_{jet}+\not{p}_{T} signature from the W±W^{\pm} and the H∓H^{\mp} decays including the NLO QCD effects, and find an observable signal at a 5σ5\sigma level in some parameter region of the minimal supergravity model.Comment: version to be published in Phys.Rev.

    Food Safety Knowledge and Practice Among Community in Sg. Pelek, Sepang, Selangor Darul Ehsan

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    Food safety is a basic requirement of food quality. It is an increasingly important public health issue to prevent and control food borne illnesses. A cross-sectional study was designed to determine level of knowledge and practice on food safety, to determine the association between knowledge and practice, and also to identify the association between socio-demographic factors and practice score of the population studied. This study was conducted among adult population in Taman Bahagia, Sungai Pelek, Sepang, Selangor Darul Ehsan. Data were collected using an interviewed structured questionnaire. A stratified random sampling was performed to obtain houses, followed by simple random sampling to select sample in the house. A total of 115 data sets were analysed using Statistical Package for Social Sciences (SPSS) version 20.0. Analysis showed that 35% of respondents have poor level of knowledge on food safety, whereas 27% of the respondents have poor level of practices on food safety. Multiple linear regression revealed that there are a significant association between education level (p<0.001), Adj b=2.57 (95% CI: 1.15, 3.99) and gender (p=0.048), Adj b=1.15 (95% CI: 0.01, 2.29) with practice score on food safety. Therefore, health promotion and education on the importance of practicing food safety at home should be focused to prevent further unwanted health effects

    SiO and H2O Maser Observations of Red Supergiants in Star Clusters Embedded in the Galactic Disk

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    We present the result of radio observations of red supergiants in the star cluster, Stephenson's #2, and candidates for red supergiants in the star clusters, Mercer et al. (2005)'s #4, #8, and #13, in the SiO and H2_2O maser lines.The Stephenson's #2 cluster and nearby aggregation at the South-West contain more than 15 red supergiants. We detected one at the center of Stephenson's #2 and three in the south-west aggregation in the SiO maser line, and three of these 4 were also detected in the H2O maser line. The average radial velocity of the 4 detected objects is 96 km s^{-1}, giving a kinematic distance of 5.5 kpc, which locates this cluster near the base of the Scutum-Crux spiral arm. We also detected 6 SiO emitting objects associated with the other star clusters. In addition, mapping observations in the CO J=1--0 line toward these clusters revealed that an appreciable amount of molecular gas still remains around Stephenson's #2 cluster in contrast to the prototypical red-supergiant cluster, Bica et al.'s #122. It indicates that a time scale of gas expulsion differs considerably in individual clusters.Comment: high res. figures available at http://www.nro.nao.ac.jp/~lib_pub/report/data/no674.pdf. PASJ 62, No.2 (2010, April 25 issue) in pres

    Si/Ge hole-tunneling double-barrier resonant tunneling diodes formed on sputtered flat Ge layers

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    We have demonstrated Si/Ge hole-tunneling double-barrier resonant tunneling diodes (RTDs) formed on flat Ge layers with a relaxation rate of 89% by our proposed method; in this method, the flat Ge layers can be directly formed on highly B-doped Si(001) substrates using our proposed sputter epitaxy method. The RTDs exhibit clear negative differential resistance effects in the static current–voltage (I–V) curves at room temperature. The quantized energy level estimation suggests that resonance peaks that appeared in the I–V curves are attributed to hole tunneling through the first heavy- and light-hole energy levels

    Security Attributes Based Digital Rights Management

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    Most real-life systems delegate responsibilities to different authorities. We apply this model to a digital rights management system, to achieve flexible security. In our model a hierarchy of authorities issues certificates that are linked by cryptographic means. This linkage establishes a chain of control, identity-attribute-rights, and allows flexible rights control over content. Typical security objectives, such as identification, authentication, authorization and access control can be realised. Content keys are personalised to detect illegal super distribution. We describe a working prototype, which we develop using standard techniques, such as standard certificates, XML and Java. We present experimental results to evaluate the scalability of the system. A formal analysis demonstrates that our design is able to detect a form of illegal super distribution

    Effectiveness of Hindman's theorem for bounded sums

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    We consider the strength and effective content of restricted versions of Hindman's Theorem in which the number of colors is specified and the length of the sums has a specified finite bound. Let HTk≤n\mathsf{HT}^{\leq n}_k denote the assertion that for each kk-coloring cc of N\mathbb{N} there is an infinite set X⊆NX \subseteq \mathbb{N} such that all sums ∑x∈Fx\sum_{x \in F} x for F⊆XF \subseteq X and 0<∣F∣≤n0 < |F| \leq n have the same color. We prove that there is a computable 22-coloring cc of N\mathbb{N} such that there is no infinite computable set XX such that all nonempty sums of at most 22 elements of XX have the same color. It follows that HT2≤2\mathsf{HT}^{\leq 2}_2 is not provable in RCA0\mathsf{RCA}_0 and in fact we show that it implies SRT22\mathsf{SRT}^2_2 in RCA0\mathsf{RCA}_0. We also show that there is a computable instance of HT3≤3\mathsf{HT}^{\leq 3}_3 with all solutions computing 0′0'. The proof of this result shows that HT3≤3\mathsf{HT}^{\leq 3}_3 implies ACA0\mathsf{ACA}_0 in RCA0\mathsf{RCA}_0
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