4,319 research outputs found
Muon g-2 Anomaly confronted with the higgs global data in the Left-Right Twin Higgs Models
We will examine the Left-Right Twin Higgs(LRTH) Models as a solution of muon
g-2 anomaly with the background of the Higgs global fit data. In the
calculation, the joint constrains from the theory, the precision electroweak
data, the 125 GeV Higgs data, the leptonic flavor changing decay \mu \to
e\gamma decays, and the constraints m_{\nu_R}>m_T>m_{W_H} are all considered.
And with the small mass of the \phi^0, the direct searches from the channels can impose stringent upper limits on Br(h\to
\phi^0\phi^0) and can reduce the allowed region of m_{\phi^0} and f. It is
concluded that the muon g-2 anomaly can be explained in the region of 200 GeV
\leq M\leq 500 GeV, 700 GeV \leq f\leq 1100 GeV, 13 GeV \leq m_{\phi^0}\leq 55
GeV, 100 GeV \leq m_{\phi^\pm}\leq 900 GeV, and m_{\nu_R}\geq 15 TeV after
imposing all the constraints mentioned above.Comment: 18 pages, 4 figures, some typos modifie
Effect of timing and source of online product recommendations: An eye-tracking study
Online retail business has become an emerging market for almost all business owners. Online recommender systems provide better services to the consumers as well as assist consumers with their decision making processes. In this study, a controlled lab experiment was conducted to assess the effect of recommendation timing (early, mid, and late) and recommendation source (expert reviews vs. consumer reviews) on e-commerce users\u27 interest and attention. Eye-tracking data was extracted from the experiment and analyzed. The results suggest that users show more interest in recommendation based on consumer reviews than recommendation based on expert reviews. Earlier recommendations do not receive greater user attention than later recommendations --Abstract, page iii
Biochemical and Biophysical Studies of Wild-Type and Active-Site Mutants of Human Adenosine Deaminase.
The focus of this work is structural and functional studies of wild-type and active-site mutants of human adenosine deaminase. Two active-site amino acids, Glu217 and His238, were previously substituted with alanine by site-directed mutagenesis. The Glu217Ala and His238Ala mutants showed little or no changes in Zn content and \rm K\sb{m} value, yet dramatic loss of enzyme activity. Circular dichroism studies of the solution conformation of wild-type and mutant human adenosine deaminases indicate that 30 to 50% of -helical structure is lost in Glu217Ala and His238Ala, respectively, whereas -sheet structure is fully retained. Inhibitor binding is measured by a fluorescent assay. Dissociation constants for transition-state analog inhibitors are similar for wild-type and mutant enzymes, suggesting that inhibitor and substrate binding determinants are preserved in the mutants. Protein stability studies show that Glu217Ala and His238Ala are less stable to thermal, urea, and guanidinium chloride denaturation than wild-type. Because the enzyme conformational changes caused by substitution of Glu217 and His238 mainly destabilizes the protein with only minor effects on substrate and inhibitor binding, the loss of enzyme activity is probably due to the modification of functional groups that are critical for catalysis. The active-site Zn environment of wild-type, Glu217Ala, and His238Ala mutant adenosine deaminases is probed by EXAFS. There are five ligands coordinated to Zn in the free enzyme and ground- and transition-state analog inhibitor complexes of these three adenosine deaminases, suggesting the presence of a water/hydroxide or a hydroxyl group. Zn-ligand distances of the mutants are similar to those of the wild-type, indicating that the active-site of mutants are intact upon substitution. Wild-type and His238Ala form a transition state with the transition-state analog inhibitor purine riboside whereas with Glu217Ala a ground state is formed. The findings are consistent with the proposed catalytic mechanism based on the X-ray crystal structure of mouse adenosine deaminase, and provide further insight into the effects of these active site residues on the structure, stability and function of human adenosine deaminase
Shadows and photon spheres with spherical accretions in the four-dimensional Gauss-Bonnet black hole
We investigate the shadows and photon spheres of the four-dimensional
Gauss-Bonnet black hole with the static and infalling spherical accretions. We
show that for both cases, the shadow and photon sphere are always present. The
radii of the shadow and photon sphere are independent of the profiles of
accretion for a fixed Gauss-Bonnet constant, implying that the shadow is a
signature of the spacetime geometry and it is hardly influenced by accretion in
this case. Because of the Doppler effect, the shadow of the infalling accretion
is found to be darker than that of the static one. We also investigate the
effect of the Gauss-Bonnet constant on the shadow and photon sphere, and find
that the larger the Gauss-Bonnet constant is, the smaller the radii of the
shadow and photon sphere will be. In particular, the observed specific
intensity increases with the increasing of the Gauss-Bonnet constant.Comment: published versio
- …