4,355 research outputs found
Interpretation of AMS-02 electrons and positrons data
We perform a combined analysis of the recent AMS-02 data on electrons,
positrons, electrons plus positrons and positron fraction, in a self-consistent
framework where we realize a theoretical modeling of all the astrophysical
components that can contribute to the observed fluxes in the whole energy
range. The primary electron contribution is modeled through the sum of an
average flux from distant sources and the fluxes from the local supernova
remnants in the Green catalog. The secondary electron and positron fluxes
originate from interactions on the interstellar medium of primary cosmic rays,
for which we derive a novel determination by using AMS-02 proton and helium
data. Primary positrons and electrons from pulsar wind nebulae in the ATNF
catalog are included and studied in terms of their most significant (while
loosely known) properties and under different assumptions (average contribution
from the whole catalog, single dominant pulsar, a few dominant pulsars). We
obtain a remarkable agreement between our various modeling and the AMS-02 data
for all types of analysis, demonstrating that the whole AMS-02 leptonic data
admit a self-consistent interpretation in terms of astrophysical contributions.Comment: 33 pages, 26 figures and 4 tables, v2: accepted for publication in
JCAP, minor changes relative to v
First observation of Cherenkov rings with a large area CsI-TGEM-based RICH prototype
We have built a RICH detector prototype consisting of a liquid C6F14 radiator
and six triple Thick Gaseous Electron Multipliers (TGEMs), each of them having
an active area of 10x10 cm2. One triple TGEM has been placed behind the liquid
radiator in order to detect the beam particles, whereas the other five have
been positioned around the central one at a distance to collect the Cherenkov
photons. The upstream electrode of each of the TGEM stacks has been coated with
a 0.4 micron thick CsI layer.
In this paper, we will present the results from a series of laboratory tests
with this prototype carried out using UV light, 6 keV photons from 55Fe and
electrons from 90Sr as well as recent results of tests with a beam of charged
pions where for the first time Cherenkov Ring images have been successfully
recorded with TGEM photodetectors. The achieved results prove the feasibility
of building a large area Cherenkov detector consisting of a matrix of TGEMs.Comment: Presented at the International Conference NDIP-11, Lyon,July201
Improved multi-user interaction in a smart environment through a preference-based conflict resolution virtual assistant
In this work we will examine and develop a system that can assist people in Activities of Daily Life (ADL). This study focuses on resolving conflicts for the requests from different users’ profiles, for instance - elderly, adult and young. The objective of the system is to present a dialogue manager which is able to detect multi-user semantic conflict and to resolve the conflict for improved dialogue informing about its decisions using a system interface Avatar. The system is also able to prioritize requests that occurred among the services of multiple home appliances, as well as to deal with conflicting entities involving a single device. We investigated whether the multi-user context awareness by a Virtual Assistant adds value to the Smart Home concept in recognizing multi-user conflicts dynamically. This work has proposed a preference based method for resolving conflict and evaluated the developed system in a smart home environmen
Sum-Product Network structure learning by efficient product nodes discovery
Sum-Product Networks (SPNs) are recently introduced deep probabilistic models providing exact and tractable inference. SPNs have been successfully employed in several application domains, from computer vision to natural language processing, as accurate density estimators. However, learning their structure and parameters from high dimensional data poses a challenge in terms of time complexity. Classical SPNs structure learning algorithms work by repeating several times two high cost operations: determining independencies among random variables (RVs)-introducing product nodes-and finding sub-populations among samples-introducing sum nodes. Even one of the simplest greedy structure learner, LearnSPN, scales quadratically in the number of the variables to determine RVs independencies. In this work, we investigate the trade-off between accuracy and efficiency when employing approximate but fast procedures to determine independencies among RVs. We introduce and evaluate sub-quadratic procedures based on a random subspace approach and leveraging entropy as a proxy criterion to split independent RVs. Experimental results on many benchmark datasets for density estimation show that LearnSPN-like structure learners, when equipped by our splitting procedures, provide reduced learning and/or inference times, generally containing the degradation of inference accuracy. Ultimately, we provide an empirical confirmation of a "no free lunch" when learning the structure of SPNs
Efficiency of microsatellite markers in assisted selection for resistance to soybean cyst nematode (race 3).
Four microsatellite sequences were tested in soybean DNA from cultivars and segregating genotypes. Three of them were close to the resistance locus rhg 1 on molecular linkage group G (Satt 309, Sat_168, Sat_163) and one was close to Rhg4 locus on group A2 (Sat_162). Progenies previously classified as cyst nematode (SNC) resistant and others with unknown reaction were tested, using the resistant cultivars Liderança, and Renascença and the susceptibles 'Cristalina' and 'OCEPAR-4' as control. The best primer for resistance to SCN was Sat_162. Twenty segregant progenies tested with Sat_162 presented a 150 bp band for homozygous resistant genotypes and 200 bp for susceptible ones, and both for the heterozigous genotypes. Previous studies have shown that this microsatellite marker is efficient to select genotypes carrying Peking-derivative resistance. 'Peking' takes part in the in the genealogy of all segregant progenies evaluated in this study. Thus, the obtained results showed that Sat_162 distinguished resistant and susceptible soybean genotypes to SCN, race 3
Fatty acid composition of heavy pig back fat in relationship to some animal factors.
The influence of genetic type, lean meat percentage and sex on fatty acids (FA) composition of back fat of heavy pigs, reared for the production of San Daniele dry cured ham, was studied. One-hundred pigs of four genetic types - Large White or Duroc x (Landrace x Large White), GOLAND and DANBRED - were considered. They were randomly chosen during the slaughtering of 21 lots of heavy animals, in groups of four to eight subjects, balanced by sex, female and castrated males, and carcass leanness, U and R classes following the European grading system. Principal components (PCs) analysis showed that 94.3% of lot-diets\u2019 FA variability was accounted for a five PCs model. The diet effect on the lard composition was weighted using the PCs scores as covariates in a tri-factorial (genotype, carcass leanness, sex) covariance design. Diet had a great effect on lard composition, indeed every examined back fat FA co-varied with the extracted PCs. On the other hand, sex effect never reached a significance threshold, as well as the interactions between factors. Genetic type influenced stearic acid and MUFA content and n6-PUFA to n3-PUFA ratio of back fat while leanness mainly influenced PUFA, the fatter class showing a significantly lower content of linoleic acid (13.2 vs. 11.9% total lipids in U vs. R class respectively)
Solar model with CNO revised abundances
Recent three-dimensional, NLTE analyses of the solar spectrum have shown a
significant reduction in the C, N, O and Ne abundances leading to a Z/X ratio
of the order of 0.0177. We have computed solar models with this new mixture in
the OPAL opacity tables. The present He abundance we find seems rather
consistent with the helioseismic value. However, the convective envelope is too
shallow, and diffusion, even if it reduces the discrepancy, is not able to give
the current value. We present some numerical experiments consisting in changing
the diffusion velocities and/or the value of opacity at the base of the
convective envelope.Comment: 3 pages, Proc. SOHO 14 - GONG 2004 Meeting, Yale, 12-16 July 2004,
added reference to Basu, S., Antia, H.M., 2004, ApJ 606, L8
Beam lead technology
Beam lead technology for microcircuit interconnections with applications to metallization, passivation, and bondin
Differential translocation of protein kinase C isozymes in rats characterized by a chronic lack of LTP induction and cognitive impairment
AbstractThe translocation of protein kinase C isozymes was investigated in an animal model of cognitive deficit and lack of induction of long-term potentiation (LTP). In MAM rats, presynaptic α, β, ϵ PKC showed enhanced translocation, while postsynaptic γ PKC displayed decreased translocation when compared to control levels. This imbalance of PKC isozyme translocation between the pre- and post-synaptic compartment might therefore represent a possible molecular cause for the lack of synaptic plasticity observed in these animals
Refractory vasculitic ulcer of the toe in adolescent suffering from Systemic Lupus Erythematosus treated successfully with hyperbaric oxygen therapy
Skin ulcers are a dangerous and uncommon complication of vasculitis. We describe the case of a teenager suffering from Systemic Lupus Erythematosus with digital ulcer resistant to conventional therapy, treated successfully with Hyperbaric Oxygen Therapy. The application of hyperbaric oxygen, which is used for the treatment of ischemic ulcers, is an effective and safe therapeutic option in patients with ischemic vasculitic ulcers in combination with immunosuppressive drugs. Further studies are needed to evaluate its role as primary therapy for this group of patients
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