2,697 research outputs found
Thermodynamic analysis of topological black holes in Gauss-Bonnet gravity with nonlinear source
Employing two classes of nonlinear electrodynamics, we obtain topological
black hole solutions of Gauss-Bonnet gravity. We investigate geometric
properties of the solutions and find that there is an intrinsic singularity at
the origin. We investigate the thermodynamic properties of the asymptotically
flat black holes and also asymptotically adS solutions. Using suitable local
transformation, we generalize static horizon-flat solutions to rotating ones.
We discuss their conserved and thermodynamic quantities as well as the first
law of thermodynamics. Finally, we calculate the heat capacity of the solutions
to obtain a constraint on the horizon radius of stable solutions.Comment: accepted in Eur. Phys. J. C (DOI: 10.1140/epjc/s10052-014-3079-9
Global fits to b -> s ll data and signs for lepton non-universality
There are some slight tensions with the SM predictions within the latest LHCb
measurements. Besides the known anomaly in one angular observable of the rare
decay B -> K* mu+ mu-, another small discrepancy recently occurred. The ratio
R_K = BR(B+ -> K+ mu+ mu-) / BR(B+ -> K+ e+ e-) in the low-q^2 region has been
measured by LHCb showing a 2.6 sigma deviation from the SM prediction. In
contrast to the anomaly in the rare decay B -> K* mu+ mu- which is affected by
power corrections, the ratio R_K is theoretically rather clean. We analyse all
the b -> s ll data with global fits and in particular explore the possibility
of breaking of lepton universality. Possible cross-checks with an analysis of
the inclusive B -> X_s l+ l- decay are also explored.Comment: 15 pages, 11 figures. v2: references added, to appear in JHE
On the anomalies in the latest LHCb data
Depending on the assumptions on the power corrections to the exclusive b -> s
l+ l- decays, the latest data of the LHCb collaboration - based on the 3 fb^-1
data set and on two different experimental analysis methods - still shows some
tensions with the SM predictions. We present a detailed analysis of the
theoretical inputs and various global fits to all the available b -> s l+ l-
data. This constitutes the first global analysis of the new data of the LHCb
collaboration based on the hypothesis that these tensions can be at least
partially explained by new physics contributions. In our model-independent
analysis we present one-, two-, four-, and also five-dimensional global fits in
the space of Wilson coefficients to all available b -> s l+ l- data. We also
compare the two different experimental LHCb analyses of the angular observables
in B -> K* mu+ mu-. We explicitly analyse the dependence of our results on the
assumptions about power corrections, but also on the errors present in the form
factor calculations. Moreover, based on our new global fits we present
predictions for ratios of observables which may show a sign of lepton
non-universality. Their measurements would crosscheck the LHCb result on the
ratio R_K = BR(B+ -> K+ mu+ mu-) / BR(B+ -> K+ e+ e-) in the low-q^2 region
which deviates from the SM prediction by 2.6 sigma.Comment: 41 pages, 24 figures. v2: references and comment on 1006.4945
[hep-ph] adde
Effect of sports vision exercise on visual perception and reading performance in 7- to 10-year-old developmental dyslexic children
The presented study was aimed at identifying for the first time the influence of sports vision exercises on fundamental motor skills and cognitive skills of 7- to 10-year-old developmental dyslexic Persian children. A pretest - posttest quasi-experimental study was conducted. The statistical population of this study was 7- to 10-year-old dyslexic children referring to two centres of learning disorder in the city of Isfahan. Twenty two of these children were selected using available and purposive sampling from the statistical population and were randomly assigned into two groups of experimental and control. The former (experimental group) participated in sports vision exercise courses for 12 weeks (3 one hr sessions per week) and the latter (control group) continued their routine daily activities during the exercise. Before the beginning and at the end of the exercise, Gardner’s test of visual perception test - revised and Dehkhoda’s reading skills test was administered to both groups. The results showed that the sports vision exercises increases motor skills, visual perceptual skills and reading skills in developmental dyslexic children. Based on the results of the presented study it was concluded that sports vision exercises can be used for fundamental and cognitive skills of developmental dyslexic children
QCD Corrections in two-Higgs-doublet extensions of the Standard Model with Minimal Flavor Violation
We present the QCD corrections to R_b and to the Delta B=1 effective
Hamiltonian in models with a second Higgs field that couples to the quarks
respecting the criterion of Minimal Flavor Violation, thus belonging either to
the (1,2)_1/2 or to the (8,2)_1/2 representation of SU(3)xSU(2)xU(1). After the
inclusion of the QCD corrections, the prediction for R_b becomes practically
insensitive to the choice of renormalization scheme for the top mass, which for
the type-I and type-II models translates in a more robust lower bound on
tan(beta). The QCD-corrected determinations of Rb and BR(B->Xs gamma) are used
to discuss the constraints on the couplings of a (colored) charged Higgs boson
to top and bottom quarks.Comment: 19 pages, 7 figures. v2: version published in Phys. Rev. D, with
additional reference and not
Noether gauge symmetry approach applying for the non-minimally coupled gravity to the Maxwell field
Taking the Noether gauge symmetry approach into account, we find spherically
symmetric static black hole solutions of the non-minimal gauge-gravity
Lagrangian of the model. At first, we consider a system
of differential equations for the general non-minimal couplings of
type, and then, we regard a particular non-minimal model to find the exact black hole solution and analyze its
symmetries. As the next step, we calculate the thermodynamical quantities of
the black hole and study its interesting behavior. Besides, we address thermal
stability and examine the possibility of the van der Waals-like phase
transition.Comment: 17 pages, 20 figure
Nanoparticles-cell association predicted by protein corona fingerprints
In a physiological environment (e.g., blood and interstitial fluids) nanoparticles (NPs) will bind proteins shaping a "protein corona" layer. The long-lived protein layer tightly bound to the NP surface is referred to as the hard corona (HC) and encodes information that controls NP bioactivity (e.g. cellular association, cellular signaling pathways, biodistribution, and toxicity). Decrypting this complex code has become a priority to predict the NP biological outcomes. Here, we use a library of 16 lipid NPs of varying size (Ø ≈ 100-250 nm) and surface chemistry (unmodified and PEGylated) to investigate the relationships between NP physicochemical properties (nanoparticle size, aggregation state and surface charge), protein corona fingerprints (PCFs), and NP-cell association. We found out that none of the NPs' physicochemical properties alone was exclusively able to account for association with human cervical cancer cell line (HeLa). For the entire library of NPs, a total of 436 distinct serum proteins were detected. We developed a predictive-validation modeling that provides a means of assessing the relative significance of the identified corona proteins. Interestingly, a minor fraction of the HC, which consists of only 8 PCFs were identified as main promoters of NP association with HeLa cells. Remarkably, identified PCFs have several receptors with high level of expression on the plasma membrane of HeLa cells
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