1,137 research outputs found
Millisecond pulsars and the gamma-ray excess in Andromeda
The Fermi Gamma-Ray Space Telescope has provided evidence for diffuse
gamma-ray emission in the central parts of the Milky Way and the Andromeda
galaxy. This excess has been interpreted either as dark matter annihilation
emission or as emission from thousands of millisecond pulsars (MSPs). We have
recently shown that old massive globular clusters may move towards the center
of the Galaxy by dynamical friction and carry within them enough MSPs to
account for the observed gamma-ray excess. In this paper we revisit the MSP
scenario for the Andromeda galaxy, by modeling the formation and disruption of
its globular cluster system. We find that our model predicts gamma-ray emission
times larger than for the Milky Way, but still nearly an order of
magnitude smaller than the observed Fermi excess in the Andromeda. Our MSP
model can reproduce the observed excess only by assuming times larger
number of old clusters than inferred from galaxy scaling relations. To explain
the observations we require either that Andromeda deviates significantly from
the scaling relations, or that a large part of its high-energy emission comes
from additional sources.Comment: 5 pages, 2 figures, 1 Table, accepted by ApJ Let
General Framework of Competence and International Criminal Procedural Cooperation
El autor llama la atención sobre algunos elementos de derecho internacional acogidos en la codificación procesal penal mexicana. Presenta la temática relacionada con la competencia judicial internacional, el orden jurídico regulador de los problemas de tráfico jurídico internacional, la cooperación internacional en el nuevo Código Nacional de Procedimientos Penales, incluido el reconocimiento de decisiones extranjeras, la extradición, así como la asistencia consular.The author specifically highlights some elements of the international law adopted by the Mexican Criminal Procedural Code. The article shows the topic relating to international judicial competence, the legal system governing issues of international juridical trafficking, and international cooperation in the new National Criminal Procedural Code, including the recognition of foreign decisions, extradition, and consular assistance
Variability of fibre quality on Chinese Alashan Left Banner White Cashmere goat
The heritability and the phenotypic and genetic correlations of down weight (DW), down fibre diameter (DFD), and coefficient of variation of the down fibre diameter (CVDFD) of Chinese Alashan Left Banner White Cashmere goat were estimated on 1375 one-year-old animals, born in 2009, 2011 and 2013 and bred at the Station for Livestock Improvement of Alashan (Left Banner, Inner Mongolia, P.R. China). For all traits, significant effects were for sex, cohort and sex–cohort interaction (p <.001). The heritability for DFD and CVDFD was high, 0.41 ± 0.08 and 0.52 ± 0.06, respectively. Heritability for the DW was low (0.12 ± 0.03). Phenotypic correlation calculated by Pearson’s coefficient showed that DFD is positively correlated with both CVDFD (0.29 ± 0.07) and DW (0.20 ± 0.05). The phenotypic correlation between CVDFD and DW was negative (−0.11 ± 0.06). The genetic correlations between DW and CVDFD and between DFD and CVDFD were both high and positive (0.63 ± 0.16 and 0.39 ± 0.1, respectively) while the DW showed a negative genetic correlation with DFD (−0.27 ± 0.2). Our results suggest that the selection for reducing DFD and its CVDFD is possible and a genetic progress can be achieved quickly in the Chinese Alashan Left Banner White Cashmere goat
Diesel exhaust particles suppress macrophage function and slow the pulmonary clearance of Listeria monocytogenes in rats.
In this study, we tested the hypothesis that exposure to diesel exhaust particles (DEP) may increase susceptibility of the host to pulmonary infection. Male Sprague-Dawley rats received a single dose of DEP (5 mg/kg), carbon black (CB, 5 mg/kg), or saline intratracheally. Three days later, the rats were inoculated intratracheally with approximately 5,000 Listeria monocytogenes and sacrificed at 3, 5, and 7 days postinfection, and we determined the number of viable Listeria in the left lobe of lungs. The remaining lungs underwent bronchoalveolar lavage (BAL) and the retrieved BAL cells were identified and counted. Luminol-dependent chemiluminescence, a measure of reactive oxygen species (ROS) formation, generated by BAL cells was monitored and the levels of nitric oxide and tumor necrosis factor (TNF)-[alpha] produced by macrophages in culture were determined. At 7 days postinfection, we excised the lung-draining lymph nodes and phenotyped the lymphocyte subpopulations. Exposure of rats to DEP, but not to CB, decreased the clearance of Listeria from the lungs. Listeria-induced generation of luminol-dependent chemiluminescence by pulmonary phagocytes decreased by exposure to DEP but not CB. Similarly, Listeria-induced production of NO by alveolar macrophages was negated at 3, 5, and 7 days after inoculation in DEP-exposed rats. In contrast, CB exposure had no effect on Listeria-induced NO production at 3 days after infection and had a substantially smaller effect than DEP at later days. Exposure to DEP or CB resulted in enlarged lung-draining lymph nodes and increased the number and percentage of CD4(+) and CD8(+) T cells. These results showed that exposure to DEP decreased the ability of macrophages to produce antimicrobial oxidants in response to Listeria, which may play a role in the increased susceptibility of rats to pulmonary infection. This DEP-induced suppression is caused partially by chemicals adsorbed onto the carbon core of DEP, because impaired macrophage function and decreased Listeria clearance were not observed following exposure to CB
LCrowdV: Generating Labeled Videos for Simulation-based Crowd Behavior Learning
We present a novel procedural framework to generate an arbitrary number of
labeled crowd videos (LCrowdV). The resulting crowd video datasets are used to
design accurate algorithms or training models for crowded scene understanding.
Our overall approach is composed of two components: a procedural simulation
framework for generating crowd movements and behaviors, and a procedural
rendering framework to generate different videos or images. Each video or image
is automatically labeled based on the environment, number of pedestrians,
density, behavior, flow, lighting conditions, viewpoint, noise, etc.
Furthermore, we can increase the realism by combining synthetically-generated
behaviors with real-world background videos. We demonstrate the benefits of
LCrowdV over prior lableled crowd datasets by improving the accuracy of
pedestrian detection and crowd behavior classification algorithms. LCrowdV
would be released on the WWW
Is there a role of statins in the prevention of aortic biological prostheses degeneration
It has been recently observed that statins might slow the progression of aortic stenosis or sclerosis. Preliminary reports suggested a similar positive effect in reducing the degeneration of aortic valve bioprostheses even though this hypothesis should be further proven and supported by new data. In this review the present evidences of the possible effects of statins in this field are discussed
Secular dynamics of multiplanet systems: implications for the formation of hot and warm Jupiters via high-eccentricity migration
Stars and planetary system
Experience-Driven Axon Retraction in the Pharmacologically Inactivated Visual Cortex Does Not Require Synaptic Transmission
BACKGROUND: Experience during early postnatal development plays an important role in the refinement of specific neural connections in the brain. In the mammalian visual system, altered visual experiences induce plastic adaptation of visual cortical responses and guide rearrangements of afferent axons from the lateral geniculate nucleus. Previous studies using visual deprivation demonstrated that the afferents serving an open eye significantly retract when cortical neurons are pharmacologically inhibited by applying a gamma-aminobutyric acid type A receptor agonist, muscimol, whereas those serving a deprived eye are rescued from retraction, suggesting that presynaptic activity can lead to the retraction of geniculocortical axons in the absence of postsynaptic activity. Because muscimol application suppresses the spike activity of cortical neurons leaving transmitter release intact at geniculocortical synapses, local synaptic interaction may underlie the retraction of active axons in the inhibited cortex. METHOD AND FINDINGS: New studies reported here determined whether experience-driven axon retraction can occur in the visual cortex inactivated by blocking synaptic inputs. We inactivated the primary visual cortex of kittens by suppressing synaptic transmission with cortical injections of botulinum neurotoxin type E, which cleaves a synaptic protein, SNAP-25, and blocks transmitter release, and examined the geniculocortical axon morphology in the animals with normal vision and those deprived of vision binocularly. We found that afferent axons in the animals with normal vision showed a significant retraction in the inactivated cortex, as similarly observed in the muscimol-treated cortex, whereas the axons in the binocularly deprived animals were preserved. CONCLUSIONS: Therefore, the experience-driven axon retraction in the inactivated cortex can proceed in the absence of synaptic transmission. These results suggest that presynaptic mechanisms play an important role in the experience-driven refinement of geniculocortical axons
Wavelet domain Bayesian denoising of string signal in the cosmic microwave background
An algorithm is proposed for denoising the signal induced by cosmic strings
in the cosmic microwave background (CMB). A Bayesian approach is taken, based
on modeling the string signal in the wavelet domain with generalized Gaussian
distributions. Good performance of the algorithm is demonstrated by simulated
experiments at arcminute resolution under noise conditions including primary
and secondary CMB anisotropies, as well as instrumental noise.Comment: 16 pages, 11 figures. Version 2 matches version accepted for
publication in MNRAS. Changes include substantial clarifications on our
approach and a significant reduction of manuscript lengt
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