494 research outputs found
Radiative decays of the strange-bottom mesons
In this article, we assume that the strange-bottom mesons are the
conventional mesons, and calculate the electromagnetic coupling
constants , , and using the light-cone QCD sum rules. Then
we study the radiative decays , ,
and , and observe that the
widths are rather narrow. We can search for the strange-bottom
mesons in the invariant and mass distributions in the
strong decays or in the invariant and mass
distributions in the radiative decays.Comment: 16 pages, 4 figures, revised versio
Signature of short distance physics on inflation power spectrum and CMB anisotropy
The inflaton field responsible for inflation may not be a canonical
fundamental scalar. It is possible that the inflaton is a composite of fermions
or it may have a decay width. In these cases the standard procedure for
calculating the power spectrum is not applicable and a new formalism needs to
be developed to determine the effect of short range interactions of the
inflaton on the power spectrum and the CMB anisotropy. We develop a general
formalism for computing the power spectrum of curvature perturbations for such
non-canonical cases by using the flat space K\"all\'en-Lehmann spectral
function in curved quasi-de Sitter space assuming implicitly that the
Bunch-Davis boundary conditions enforces the inflaton mode functions to be
plane wave in the short wavelength limit and a complete set of mode functions
exists in quasi-de Sitter space. It is observed that the inflaton with a decay
width suppresses the power at large scale while a composite inflaton's power
spectrum oscillates at large scales. These observations may be vindicated in
the WMAP data and confirmed by future observations with PLANCK.Comment: 17 pages, 4 figures, Extended journal version, Accepted for
publication in JCA
Reconstructing the primordial power spectrum from the CMB
We propose a straightforward and model independent methodology for
characterizing the sensitivity of CMB and other experiments to wiggles,
irregularities, and features in the primordial power spectrum. Assuming that
the primordial cosmological perturbations are adiabatic, we present a function
space generalization of the usual Fisher matrix formalism, applied to a CMB
experiment resembling Planck with and without ancillary data. This work is
closely related to other work on recovering the inflationary potential and
exploring specific models of non-minimal, or perhaps baroque, primordial power
spectra. The approach adopted here, however, most directly expresses what the
data is really telling us. We explore in detail the structure of the available
information and quantify exactly what features can be reconstructed and at what
statistical significance.Comment: 43 pages Revtex, 23 figure
A Minimal Inflation Scenario
We elaborate on a minimal inflation scenario based entirely on the general
properties of supersymmetry breaking in supergravity models. We identify the
inflaton as the scalar component of the Goldstino superfield. We write
plausible candidates for the effective action describing this chiral
superfield. In particular the theory depends (apart from parameters of O(1)) on
a single free parameter: the scale of supersymmetry breaking. This can be fixed
using the amplitude of CMB cosmological perturbations and we therefore obtain
the scale of supersymmetry breaking to be 10^{12-14} GeV. The model also
incorporates explicit R-symmetry breaking in order to satisfy the slow roll
conditions. In our model the eta-problem is solved without extra fine-tuning.
We try to obtain as much information as possible in a model independent way
using general symmetry properties of the theory's effective action, this leads
to a new proposal on how to exit the inflationary phase and reheat the
Universe.Comment: matches published version (typo corrected
Genetic variants in the PPARD-PPARGC1A-NRF-TFAM mitochondriogenesis pathway are neither associated with muscle characteristics nor physical performance in elderly
We studied the influence of genetic polymorphisms involved in the PPARD-PPARGC1A-NRF-TFAM mitochondriogenesis pathway (rs6949152, rs12594956, rs2267668, rs8192678, and rs1937) on muscle phenotypes (thigh muscles’ cross-sectional, maximal handgrip-strength and 30-second chair stand-test) and Barthel index in Caucasian (Spanish) community-dwelling old people (n=75, 21 men, 54 women; 71–94 years). We found no significant genetic associations with the studied phenotypes. Multiple, com- plex gene-environment and gene-gene interactions which are yet to be determined are likely to play a more determinant role
Angular Dependence in Proton-Proton Correlation Functions in Central and Reactions
The angular dependence of proton-proton correlation functions is studied in
central and nuclear reactions at E=80
MeV/A. Measurements were performed with the HiRA detector complemented by the
4 Array at NSCL. A striking angular dependence in the laboratory frame is
found within p-p correlation functions for both systems that greatly exceeds
the measured and expected isospin dependent difference between the neutron-rich
and neutron-deficient systems. Sources measured at backward angles reflect the
participant zone of the reaction, while much larger sources observed at forward
angles reflect the expanding, fragmenting and evaporating projectile remnants.
The decrease of the size of the source with increasing momentum is observed at
backward angles while a weaker trend in the opposite direction is observed at
forward angles. The results are compared to the theoretical calculations using
the BUU transport model.Comment: 8 pages, 3 figures, submitted to PR
Estudio anatómico del glande del cuy (Cavia porcellus) de la raza Perú
The purpose of the study was to describe the macroscopic and microscopic characteristics of the structures that conforms the penis glans of the Peruvian guinea pig, and changes in the structure related to animal age. The study was conducted in 24 guinea pigs distributed in four age groups (1, 2 3, 5 months) of the Peru breed, where 20 samples taken for the macroscopic study and four for the microscopic study. The glans external surface is covered by small corneous scales of convex edge with tiny spicules directed to cranial. In the dorsal and ventral-lateral surfaces is observed the presence of extended and well-developed scales that are convex and have a free edge, with spicules directed dorsal-cranial. The glans sac is located dorsal to the penile urethra and the internal wall is covered by small scales and longitudinal folds and contains a pair of keratinaceous styluses. The os penis has an extended shape and related to the ventral surface of the glans. The glans showed a transition epithelium and lax vascular tissue. The stylus processes have a thick corneous layer of keratin and the os penis is formed of spongy bone tissue. The free end of the stylus processes becomes sharper, divergent and in some cases asymmetric with age.El presente estudio tuvo como objetivo describir las características macroscópicas y microscópicas de las estructuras que conforman el glande del pene del cuy y sus modificaciones influenciadas por la edad. El estudio se realizó en 24 cuyes distribuidos en cuatro grupos etarios (1, 2 3, 5 meses) de la raza Perú. Se utilizaron 20 muestras para el estudio macroscópico y cuatro muestras para el estudio microscópico. La superficie externa del glande presentó escamas córneas pequeñas, de borde convexo, acompañado de diminutas espículas dirigidas en craneal. En la superficie dorsal y ventrolateral se observó la presencia de escamas desarrolladas de forma alargada con el borde libre convexo y con numerosas espículas dirigidas en sentido dorsocraneal. El saco del glande se situó dorsal a la uretra peneana y la superficie interna poblada de pequeñas escamas y pliegues longitudinales. El saco del glande contiene en su interior un par de procesos estiloides, de naturaleza córnea que se originan en su base. El hueso del pene es de forma alargada y se relaciona a la superficie ventral del glande. El glande presentó un epitelio de transición, que asienta en tejido conectivo laxo vascularizado. Los procesos estiloides al corte transversal presentaron un grueso estrato córneo compuesto por capas de queratina, y el os penis se encuentra formado por tejido óseo esponjoso. Con el avance de la edad los extremos de los procesos estiloides se agudizan, se vuelven divergentes y en algunos casos asimétricos
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Is there an association between ACTN3 R577X polymorphism and muscle power phenotypes in young, non-athletic adults?
We investigated the association between ACTN3 R577X polymorphism and jumping (vertical squat and counter-movement jump tests) and sprint ability (30 m dash) in non-athletic, healthy young adults [N=284 (217 male), mean (SD) age: 21 (2) years]. We analyzed the differences in the study phenotypes among ACTN3 R577X genotypes by one-way analysis of covariance before and after adjusting for sex, age, weight and height (confounders). We also compared the genotype and allele frequencies between those with the best and worst results in the aforementioned tests (≥90th vs 0.05). In summary, α-actinin-3 deficiency does not negatively influence the ability to generate explosive leg muscle power in a young non-athletic population
ACTN3 R577X Polymorphism does not Influence Explosive Leg Muscle Power in Elite Volleyball Players
We examined the association of R577X polymorphism (rs1815739) in the α-actinin-3 (ACTN3) gene with “explosive” leg muscle power performance in a group of male and female elite volleyball players (n=66, 31 men, 35 women) and in a group of non-athletic male and female young adults (n=334, 243 men, 91 women). We assessed power performance by means of the vertical squat and counter-movement jump tests. We also determined whether the genotypic frequencies of the ACTN3 R577X genotypes differed between groups. We did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in both groups, regardless of gender (all P>0.05). Genotype frequencies were similar between volleyball and control groups (P=0.095). Moreover, we did not find an association between the ACTN3 R577X polymorphism and the likelihood of being an elite volleyball player using the dominant (RR vs RX+XX) and the recessive model (RR+RX vs XX). In summary, these findings suggest that the ACTN3 R577X polymorphism does not influence explosive leg muscle power in elite volleyball players
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