1,832 research outputs found
Empirical testing of Tsallis' Thermodynamics as a model for dark matter halos
We study a dark matter halo model from two points of view: the ``stellar
polytrope'' (SP) model coming from Tsallis' thermodynamics, and the one coming
from the Navarro-Frenk-White (NFW) paradigm. We make an appropriate comparison
between both halo models and analyzing the relations between the global
physical parameters of observed galactic disks, coming from a sample of actual
galaxies, with the ones of the unobserved dark matter halos, we conclude that
the SP model is favored over the NFW model in such a comparison.Comment: 5 pages, 1 figure, To appear in the Proceedings of X Mexican Workshop
on Particles and Fields, Morelia Michoac\'an, M\'exico, November 7-12, 200
Vitellogenin receptors during vitellogenesis in the rainbow trout Oncorhynchus mykiss
Rainbow trout vitellogenin receptors have been characterized by ligand blotting and Scatchard analysis. Their evolution has been studied over a reproductive cycle in a broodstock of 2-year-old females. The receptors were prepared from ovarian membrane homogenates and were solubilized using n-octyl-beta-D-glucopyranoside. The visualization of the receptor by ligand blotting using 125iodine-vitellogenin after sodium dodecyl sulfate electrophoresis revealed the existence of one major binding component corresponding to a protein of 113 kDa. The Scatchard transformation of the binding data revealed a single class of binding sites. The variations of the binding characteristics (Kd and maximum binding) were investigated during vitellogenesis. This study revealed that the Kd was not affected by oocyte growth during vitellogenesis, but was highly decreased in ovulated eggs. The receptor number increased during the same period from 35 to 860 fM per oocyte, while the receptor number per mm2 of oocyte membrane surface was doubled during the same period. (Résumé d'auteur
Entropy considerations in constraining the mSUGRA parameter space
We explore the use of two criteria to constraint the allowed parameter space
in mSUGRA models. Both criteria are based in the calculation of the present
density of neutralinos as dark matter in the Universe. The first one is the
usual ``abundance'' criterion which is used to calculate the relic density
after the ``freeze-out'' era. To compute the relic density we used the
numerical public code micrOMEGAs. The second criterion applies the
microcanonical definition of entropy to a weakly interacting and
self-gravitating gas evaluating then the change in the entropy per particle of
this gas between the ``freeze-out'' era and present day virialized structures.
An ``entropy-consistency'' criterion emerges by comparing theoretical and
empirical estimates of this entropy. The main objective of our work is to
determine for which regions of the parameter space in the mSUGRA model are both
criteria consistent with the 2 bounds according to WMAP for the relic
density: . As a first result, we found that for
, sgn, small values of tan are not favored; only for
tan are both criteria significantly consistent.Comment: 5 pages, 1 figure. To appear in the Proceedings of X Mexican Workshop
on Particles and Fields, Morelia Michoac\'an, M\'exico, November 7-12, 200
Testicular structure, spermatogenesis and sperm cryopreservation in the African clariid catfish Heterobranchus longifilis (Valenciennes, 1840)
The morphological and physiological characteristics of the testes and the sperm of the catfish #Heterobranchus longifilis$ (Val.) are presented. The effect of cryopreservation on the fertilizing capacity of the sperm was also evaluated. Testicular structure and spermatogenesis are described using histological techniques. The coexistence in the lobules of spermatozoa and all the spermatogenic stages indicates that this species is able to perform continuous reproduction. No seasonal trend was noticed in the evolution of the gonadosomatic index and in the quantity of the sperm produced over a year's period. However, maximum sperm production was observed in April and September. Different cryopreservation trials were conducted using a cryoprotective solution composed of 5% dimethylsulphoxide (DMSO), 5% glycerol, 10% hen's eggyolk and 80% Mounib's solution. Fresh and cryopreserved semen gave equivalent hatching rates (81.1%, 83.4% and 78.9% respectively for the fresh, the 1-hour cryopreserved and the 8-month cryopreserved sperm). Percentages of normal and deformed larvae were not affected by sperm cryopreservation. (Résumé d'auteur
MySmartPi
Nowadays, accessing the Internet in a secure way in a big concern for many people due to the increase of cybersecurity attacks and the vulnerability of the data that is transferred online. In order to address such vulnerabilities, the use of a Virtual Private Network is really important. Not only for security reasons, but also to access resources of the network, such as printers, files or web pages. Considering that many people, especially IT students, have curiosity and enjoy creating their own technologies, this project aims to create a user manual to teach how people can create their own VPN server at home using a Raspberry Pi and to access their files and folders which are in the network. For that, tutorials were used and adapted in order to install the VPN server and NAS. In order to prove that the whole process was successful, some tools, such as, Wireshark, were used to show how the network traffic works once the VPN is used. The process was successful and many concepts were learnt and used such as Cryptography, Port forwarding, dynamic DNS, OpenVPN, etc
Seasonality of reproduction of Piaractus brachypomus in South Bolivia
The reproductive period of Piaractus brachypomus is short in South Bolivia. This area is close to the Southern limit of the species and conditions favourable to its reproduction last for only a few months. In order to increase fry production, we studied the possibility of extending its spawning period in captivity
FuSSI-Net: Fusion of Spatio-temporal Skeletons for Intention Prediction Network
Pedestrian intention recognition is very important to develop robust and safe
autonomous driving (AD) and advanced driver assistance systems (ADAS)
functionalities for urban driving. In this work, we develop an end-to-end
pedestrian intention framework that performs well on day- and night- time
scenarios. Our framework relies on objection detection bounding boxes combined
with skeletal features of human pose. We study early, late, and combined (early
and late) fusion mechanisms to exploit the skeletal features and reduce false
positives as well to improve the intention prediction performance. The early
fusion mechanism results in AP of 0.89 and precision/recall of 0.79/0.89 for
pedestrian intention classification. Furthermore, we propose three new metrics
to properly evaluate the pedestrian intention systems. Under these new
evaluation metrics for the intention prediction, the proposed end-to-end
network offers accurate pedestrian intention up to half a second ahead of the
actual risky maneuver.Comment: 5 pages, 6 figures, 5 tables, IEEE Asilomar SS
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