6,170 research outputs found
Dark matter coupling to electroweak gauge and Higgs bosons: an effective field theory approach
If dark matter is a new species of particle produced in the early universe as
a cold thermal relic (a weakly-interacting massive particle-WIMP), its present
abundance, its scattering with matter in direct-detection experiments, its
present-day annihilation signature in indirect-detection experiments, and its
production and detection at colliders, depend crucially on the WIMP coupling to
standard-model (SM) particles. It is usually assumed that the WIMP couples to
the SM sector through its interactions with quarks and leptons. In this paper
we explore the possibility that the WIMP coupling to the SM sector is via
electroweak gauge and Higgs bosons. In the absence of an ultraviolet-complete
particle-physics model, we employ effective field theory to describe the
WIMP--SM coupling. We consider both scalars and Dirac fermions as possible
dark-matter candidates. Starting with an exhaustive list of operators up to
dimension 8, we present detailed calculation of dark-matter annihilations to
all possible final states, including gamma gamma, gamma Z, gamma h, ZZ, Zh, W+
W-, hh, and f fbar, and demonstrate the correlations among them. We compute the
mass scale of the effective field theory necessary to obtain the correct
dark-matter mass density, and well as the resulting photon line signals
Smooth empirical Bayes estimation of observation error variances in linear systems
A smooth empirical Bayes estimator was developed for estimating the unknown random scale component of each of a set of observation error variances. It is shown that the estimator possesses a smaller average squared error loss than other estimators for a discrete time linear system
Identification of Colour Reconnection using Factorial Correlator
A new signal is proposed for the colour reconnection in the hadronic decay of
W+ W- in e+e- collisions. Using Pythia Monte Carlo it is shown that this
signal, being based on the factorial correlator, is more sensitive than the
ones using only averaged quantities.Comment: 6 pages 1 postscript figur
PINK1 protects against oxidative stress by phosphorylating mitochondrial chaperone TRAP1.
Mutations in the PTEN induced putative kinase 1 (PINK1) gene cause an autosomal recessive form of Parkinson disease (PD). So far, no substrates of PINK1 have been reported, and the mechanism by which PINK1 mutations lead to neurodegeneration is unknown. Here we report the identification of TNF receptor-associated protein 1 (TRAP1), a mitochondrial molecular chaperone also known as heat shock protein 75 (Hsp75), as a cellular substrate for PINK1 kinase. PINK1 binds and colocalizes with TRAP1 in the mitochondria and phosphorylates TRAP1 both in vitro and in vivo. We show that PINK1 protects against oxidative-stress-induced cell death by suppressing cytochrome c release from mitochondria, and this protective action of PINK1 depends on its kinase activity to phosphorylate TRAP1. Moreover, we find that the ability of PINK1 to promote TRAP1 phosphorylation and cell survival is impaired by PD-linked PINK1 G309D, L347P, and W437X mutations. Our findings suggest a novel pathway by which PINK1 phosphorylates downstream effector TRAP1 to prevent oxidative-stress-induced apoptosis and implicate the dysregulation of this mitochondrial pathway in PD pathogenesis
Could CuB be the site of redox linkage in cytochrome c oxidase?
This paper explores the proton pumping function of cytochrome c oxidase [ferrocytochrome-c:oxygen oxidoreductase (EC 1.9.3.1)] based upon redox linkage at the "high-potential" CU(B) center. A model is proposed that is derived from a redox-linked ligand exchange mechanism previously described for the Cu(A) site. Qualitative analysis of this mechanism indicates that such a mechanism is feasible. However, the relatively short distance between Cu(B) and cytochrome a3 implies that the uncoupling electron transfers are quite facile. In addition, the position of the Cu(B) center with respect to the inner mitochondrial membrane argues against redox linkage at the Cu(B) site
Two electrophoreses in different pH buffers to purify forest soil DNA contaminated with humic substances
Direct extraction of DNA from soils is a useful way to gain genetic information on the soil source. However, DNA extraction from soils, especially forest soils, may be contaminated by humic substances due to their similar physical and chemical characteristics to soil. Even commercial soil DNA extractionkits fail to retrieve DNA from these soils. Using the potential changes of specific charge of DNA and humic substances in a pH solution, we performed two electrophoreses in different pH buffers to eliminate the interfering substances. The method produced high quality soil DNA, which is applicablefor PCR amplification
Menjadikan Mata Kuliah Pendidikan Pancasila sebagai Media Penanaman Nilai-nilai Bela Negara
National defense is not only to maintain the unity of the Republic of Indonesia, but it must be realized in real life to create critical, loyality, and determination of the nation. This study aimed at finding out the efforts to build the value of defending nation through the Education of Pancasila in Universitas PGRI Palembang. The method used was qualitative case study. The techniques used for collecting data were interview, documentation, observation and literature review. The data collection, data reduction, data presentation, and conclusions were analyzed simultaneously and interactively by using qualitative analysis. The result of this research stated that (1) the students of Universitas PGRI Palembang still had limited knowledge about the values of nation defense, (2) the students did not have critical attitude towards the problems around them, (3) the students had low achievement in motivation. The efforts done by Universitas PGRI Palembang in handling with these problems were fostering: (1) the values of love of the nation (2) fostering the value of national and state awareness, (3) fostering the values of Pancasila as the ideology of the nation, 4) the value of loyalty to the nation, (5) the knowledge of nation defense, and (6) the spirit of achievement as a reflection of the love of the nation
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