2,709 research outputs found
Anomalous gauge couplings of the Higgs boson at the CERN LHC: Semileptonic mode in WW scatterings
We make a full tree level study of the signatures of anomalous gauge
couplings of the Higgs boson at the CERN LHC via the semileptonic decay mode in
WW scatterings. Both signals and backgrounds are studied at the hadron level
for the Higgs mass in the range 115 GeV to 200 GeV. We carefully impose
suitable kinematical cuts for suppressing the backgrounds. To the same
sensitivity as in the pure leptonic mode, our result shows that the
semileptonic mode can reduce the required integrated luminosity by a factor of
3. If the anomalous couplings in nature are actually larger than the
sensitivity bounds shown in the text, the experiment can start the test for an
integrated luminosity of 50 inverse fb.Comment: PACS numbers updated. Version published in Phys.Rev.D79,055010(2009
Radio Polarization of BL Lacertae objects
In this paper, using the database of the university of Michigan Radio
Astronomy Observatory (UMRAO) at three (4.8 GHz, 8 GHZ, and 14.5 GHz) radio
frequencies, we studied the polarization properties for 47 BL Lacertae
objects(38 radio selected BL Lacertae objects, 7 X-ray selected BL Lacertae,
and two inter-middle objects (Mkn 421 and Mkn 501), and found that (1) The
polarizations at higher radio frequency is higher than those at lower
frequency, (2) The variability of polarization at higher radio frequency is
higher than those at lower frequency, (3) The polarization is correlated with
the radio spectral index, and (4) The polarization is correlated with
core-dominance parameter for those objects with known core-dominance parameters
suggesting that the relativistic beaming could explain the polarization
characteristic of BL Lacs.Comment: 5 pages, 3 figures, 1 table. PASJ, in pres
Separation of Different Contributions to the Total X-ray Luminosity in Gamma-ray Loud Blazars
The relativistic beaming model has been successfully used to explain many of the observational properties of active galactic nuclei. In this model the total emission is formed by two components, one beamed, one unbeamed. However, the exact contribution from each component in unresolved sources is still not clear. In the radio band, the core and extended emissions are clearly separated. We adopt the method proposed by Kembhavi to separate the two contributions in the X-ray emissions in a sample of 19 gamma-ray loud blazars. It is clearly shown that the beamed emission dominates the X-ray flux and the unbeamed X-ray emission is correlated with the extended radio emission of the considered objects. We also find that the ratio of the beamed to the unbeamed X-ray luminosity is correlated with the X-ray spectral index, an effect that should be a consequence of the underlying X-ray emission mechanism.Fil: Fan, Jun Hui. Guangzhou University. Center for Astrophysics; ChinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Wang, Yong Xiang. College of Science and Trade; ChinaFil: Zhang, Jiang Shui. Guangzhou University. Center for Astrophysics; Chin
Mutational bias of Turnip Yellow Mosaic Virus in the context of host anti-viral gene silencing
Plant Dicer-like (DCL) enzymes exhibit a GC-preference during anti-viral post-transcriptional gene silencing (PTGS), delivering an evolutionary selection pressure resulting in plant viruses with GC-poor genomes. However, some viruses, e.g. Turnip Yellow Mosaic Virus (TYMV, genus Tymovirus) have GC-rich genomes, raising the question as to whether or not DCL derived selection pressure affects these viruses. In this study we analyzed the virus-derived small interfering RNAs from TYMV-infected leaves of Brassica juncea showed that the TYMV population accumulated a mutational bias with AU replacing GC (GC–AU), demonstrating PTGS pressure. Interestingly, at the highly polymorphic sites the GC–AU bias was no longer observed. This suggests the presence of an unknown mechanism preventing mutational drift of the viral population and maintaining viral genome stability, despite the host PTGS pressure
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Systematic reconstruction of autism biology from massive genetic mutation profiles
Autism spectrum disorder (ASD) affects 1% of world population and has become a pressing medical and social problem worldwide. As a paradigmatic complex genetic disease, ASD has been intensively studied and thousands of gene mutations have been reported. Because these mutations rarely recur, it is difficult to (i) pinpoint the fewer disease-causing versus majority random events and (ii) replicate or verify independent studies. A coherent and systematic understanding of autism biology has not been achieved. We analyzed 3392 and 4792 autism-related mutations from two large-scale whole-exome studies across multiple resolution levels, that is, variants (single-nucleotide), genes (protein-coding unit), and pathways (molecular module). These mutations do not recur or replicate at the variant level, but significantly and increasingly do so at gene and pathway levels. Genetic association reveals a novel gene + pathway dual-hit model, where the mutation burden becomes less relevant. In multiple independent analyses, hundreds of variants or genes repeatedly converge to several canonical pathways, either novel or literature-supported. These pathways define recurrent and systematic ASD biology, distinct from previously reported gene groups or networks. They also present a catalog of novel ASD risk factors including 118 variants and 72 genes. At a subpathway level, most variants disrupt the pathway-related gene functions, and in the same gene, they tend to hit residues extremely close to each other and in the same domain. Multiple interacting variants spotlight key modules, including the cAMP (adenosine 3′,5′-monophosphate) second-messenger system and mGluR (metabotropic glutamate receptor) signaling regulation by GRKs (G protein–coupled receptor kinases). At a superpathway level, distinct pathways further interconnect and converge to three biology themes: synaptic function, morphology, and plasticity
Sensitivity of Space-based Gravitational-Wave Interferometers to Ultralight Bosonic Fields and Dark Matter
Ultralight bosonic fields (ULBFs) are predicted by various theories beyond
the standard model of particle physics and are viable candidates of cold dark
matter. There have been increasing interests to search for the ULBFs in
physical and astronomical experiments. In this paper, we investigate the
sensitivity of several planned space-based gravitational-wave interferometers
to ultralight scalar and vector fields. Using time-delay interferometry (TDI)
to suppress the overwhelming laser frequency noise, we derive the averaged
transfer functions of different TDI combinations to scalar and vector fields,
and estimate the impacts of bosonic field's velocities. We obtain the
sensitivity curves for LISA, Taiji and TianQin, and explore their projected
constraints on the couplings between ULBFs and standard model particles,
illustrating with the ULBFs as dark matter.Comment: 33 pages, 8 figure
The yeast prion protein Ure2: Structure, function and folding
The Saccharomyces cerevisiae protein Ure2 functions as a regulator of nitrogen metabolism and as a glutathione-dependent peroxidase. Ure2 also has the characteristics of a prion, in that it can undergo a heritable conformational change to an aggregated state; the prion form of Ure2 loses the regulatory function, but the enzymatic function appears to be maintained. A number of factors are found to affect the prion properties of Ure2, including mutation and expression levels of molecular chaperones, and the effect of these factors on structure and stability are being investigated. The relationship between structure, function and folding for the yeast prion Ure2 are discussed
(Z)-2-Hydroxy-3-(4-methoxyphenyl)acrylic acid
In the structure of the title compound, C10H10O4, inversion dimers linked by pairs of O—H⋯O hydrogen bonds link the carboxylic acid groups. Further O—H⋯O links cross-link the dimers into sheets running along the b-axis direction
(Z)-2-Acetamido-3-(4-chlorophenyl)acrylic acid
In the title compound, C11H10ClNO3, the molecule consists of a benzene ring and an acetamidoacrylic acid unit on opposite sides of the C=C double bond. In the crystal, intermolecular O—H⋯O and N—H⋯O hydrogen bonds assemble the molecules into infinite two-dimensional ribbons. These ribbons are linked into a network by intermolecular C—H⋯π contacts
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