817 research outputs found
On the full Boltzmann equations for Leptogenesis
We consider the full Boltzmann equations for standard and soft leptogenesis,
instead of the usual integrated Boltzmann equations which assume kinetic
equilibrium for all species. Decays and inverse decays may be inefficient for
thermalising the heavy-(s)neutrino distribution function, leading to
significant deviations from kinetic equilibrium. We analyse the impact of using
the full kinetic equations in the case of a previously generated lepton
asymmetry, and find that the washout of this initial asymmetry due to the
interactions of the right-handed neutrino is larger than when calculated via
the integrated equations. We also solve the full Boltzmann equations for soft
leptogenesis, where the lepton asymmetry induced by the soft SUSY-breaking
terms in sneutrino decays is a purely thermal effect, since at T=0 the
asymmetry in leptons cancels the one in sleptons. In this case, we obtain that
in the weak washout regime (K ~< 1) the final lepton asymmetry can change up to
a factor four with respect to previous estimates.Comment: 34 pages, 6 figures, to be published in JCA
The Dark Matter Density in the Solar Neighborhood reconsidered
Both the gas flaring and the dip in the rotation curve, which was recently
reconfirmed with precise measurements using the VERA VLBI array in Japan,
suggest doughnut-like substructure in the dark matter (DM) halo. A global fit
to all available data shows that the data are indeed best described by an NFW
DM profile complemented by two doughnut-like DM substructures with radii of 4.2
and 12.4 kpc, which coincide with the local dust ring and the Monocerus ring of
stars, respectively. Both regions have been suggested as regions with tidal
streams from "shredded" satellites. If real, the radial extensions of these
nearby ringlike structures enhance the local dark matter density by a factor of
four to about 1.3 GeV/cm.
It is shown that i) this higher DM density is perfectly consistent with the
local gravitational potential determining the surface density and the local
matter density (Oort limit), ii) previous determinations of the surface density
were biased by the assumption of a smoothly varying DM halo and iii) the
s-shaped gas flaring is explained. Such a possible enhancement of the local DM
density is of great interest for direct DM searches and would change the
directional dependence for indirect DM searches.Comment: 14 pages, 4 figures, extended version, accepted for publication in
JCA
Regional differences of testicular artery blood flow in post pubertal and pre-pubertal dogs
Background
Measurement of testicular artery blood flow is used in several species to evaluate reproductive function and testicular and scrotal pathology. In dogs there are inconsistent reports about normal flow in post-pubertal dogs and no information concerning pre-pubertal dogs. The aim of this study was to describe regional differences in testicular artery blood flow in clinically normal post-pubertal and pre-pubertal dogs with no history of reproductive tract disease.
Results
The post-pubertal dogs produced normal ejaculates throughout the study. In all dogs the three different regions of the artery were imaged and monophasic flow with an obvious systolic peak and flow throughout diastole was observed on every occasion. The highest peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured within the distal supra-testicular artery and marginal artery whilst the lowest PSV and EDV were measured within the intra-testicular arteries. Flow measurements were not different between left and right testes and were consistent between dogs on different examination days. Calculated resistance index (RI) and pulsatility index (PI) were lowest in the intra-testicular arteries.
The pre-pubertal dogs had significantly smaller testes than the post-pubertal dogs (p < 0.05) and were unable to ejaculate during the study. The three different artery regions were imaged at every examination time point, and flow profiles had a similar appearance to those of the post-pubertal dogs. PSV, EDV, RI and PI showed a similar trend to the post-pubertal dogs in that values were lowest in the intra-testicular arteries. Notably, values of PSV, EDV, RI and PI were significantly lower (p < 0.05) in pre-pubertal dogs compared with post-pubertal dogs.
Conclusions
This study demonstrated important regional and pubertal differences in testicular artery blood flow of dogs, and form the basis for establishing baseline reference values that may be employed for the purposes of clinical diagnosis
Validity of numerical trajectories in the synchronization transition of complex systems
We investigate the relationship between the loss of synchronization and the
onset of shadowing breakdown {\it via} unstable dimension variability in
complex systems. In the neighborhood of the critical transition to strongly
non-hyperbolic behavior, the system undergoes on-off intermittency with respect
to the synchronization state. There are potentially severe consequences of
these facts on the validity of the computer-generated trajectories obtained
from dynamical systems whose synchronization manifolds share the same
non-hyperbolic properties.Comment: 4 pages, 4 figure
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Measurement of the top pair production cross section in 8 TeV proton-proton collisions using kinematic information in the lepton plus jets final state with ATLAS
A measurement is presented of the inclusive production
cross-section in collisions at a center-of-mass energy of TeV
using data collected by the ATLAS detector at the CERN Large Hadron Collider.
The measurement was performed in the lepton+jets final state using a data set
corresponding to an integrated luminosity of 20.3 fb. The cross-section
was obtained using a likelihood discriminant fit and -jet identification was
used to improve the signal-to-background ratio. The inclusive
production cross-section was measured to be
pb assuming a top-quark mass of 172.5 GeV, in good agreement with the
theoretical prediction of pb. The production cross-section in the fiducial region
determined by the detector acceptance is also reported.Comment: Published version, 19 pages plus author list (35 pages total), 3
figures, 2 tables, all figures including auxiliary figures are available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-06
Potential alternative feed sources for ruminant feeding from the biodiesel production chain by-products
This study aimed to evaluate the chemical composition, fractionation of nitrogen compounds and carbohydrates, digestibility parameters, gas production kinetics and ruminal fermentation of fruit seed cakes. The experiment was conducted in a completely randomized design with three fruit seed cakes (treatments) and four replications. The cakes were made of seeds of custard apple (Annona squamosa), soursop (Annona muricata) and passion fruit (Passiflora edulis), which were collected in a biodiesel plant. The passion fruit seed cake presented the highest content of dry matter, neutral detergent fibre crude protein (NDFcp), acid detergent fibre (ADF), lignin and total carbohydrates (P<0.05). The custard apple seed cake presented high proportions of crude protein, condensed tannins and digestible energy (P<0.05). The soursop seed cake presented higher values for ether extract and total digestible nutrients (P<0.05). For potential degradability, the authors detected a difference between the custard apple, soursop and passion fruit seed cakes. The total volume of gases was higher for custard apple and soursop seed cakes. Custard apple seed cake presented higher proportions of in vitro degradation parameters (P<0.05). Thus this cake could provide greater nutrient levels when supplied in ruminant diets, followed by soursop seed cake and passion fruit seed cake.
Keywords: alternative food, by-products, ruminant feeding, seed cake, semi-ari
Multidisciplinary Experience In The Selection Of Patients For Tubal Sterilization.
Results of the use of a special protocol for evaluation of patients requiring tubal ligation is presented after applied by a multidisciplinary group. The authors conclude that the use of defined parameters of age, parity, marital union duration, number of children alive and the presence of maternal clinical pathology are useful to identify patients with smaller chances of regret after surgery.27% of reproductive-age women in Brazil have chosen surgical sterilization as their contraceptive method. Most of these women who have undergone tubal sterilization opted for cesarean surgery. However, given the young ages of many of these women, many regret having been sterilized. This paper summarizes the experience of a multidisciplinary group in evaluating women who apply for surgical sterilization at the Department of Tocogynecology, Faculdade de Ciencas Medicas, Universidade Estadual de Campinas in Sao Paulo. Detailed descriptions are presented of the medical and social characteristics of cases seen between June 1988 and July 1989. The authors conclude that the use of the defined parameters of age, parity, marital union duration, number of living children, and the presence of maternal clinical pathology are useful in identifying the patients who are least likely to regret undergoing surgical sterilization.113171572
The Portuguese Third Version of the Copenhagen Psychosocial Questionnaire: Preliminary Validation Studies of the Middle Version among Municipal and Healthcare Workers
A third version of the Copenhagen Psychosocial Questionnaire (COPSOQ III) was developed
internationally aiming to respond to new trends in working conditions, theoretical concepts,
and international experience. This article aims to present the preliminary validation studies for the Portuguese middle version of COPSOQ III. This is an exploratory cross-sectional study viewing the cross-cultural adaption of COPSOQ III to Portugal, ensuring the contents and face validity and performing field-testing in order to reduce the number of items and to obtain insight into the data structure, through classic test theory and item response theory approaches. The qualitative study encompassed 29 participants and the quantitative one 659 participants from municipalities and healthcare settings. Content analysis suggested that minor re-wording could improve the face validity of items, while a reduced version, with 85 items, shows psychometric stability, achieving good internal consistency in all subscales. The COPSOQ III Portuguese middle version proved to be a valid preliminary version for future validation studies with various populations, able to be used in correlational studies with other dimensions
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