Les techniques actuelles d'estimation de la composition corporelle des bovins : étude pratique de deux méthodes utilisant les ultrasons

La connaissance de la composition corporelle des bovins est depuis longtemps un outil indispensable à la conduite du troupeau laitier ou allaitant ; ce paramètre est aussi un critère de sélection des taureaux de races bouchères. Ainsi, après une présentation du mode de croissance des bovins et de la physiologie du tissu adipeux, l'auteur s'intéresse aux techniques d'appréciation de leur composition corporelle en insistant sur l'échographie et le VOS . Ces deux méthodes sont ensuite utilisées dans une étude expérimentale, les mesures obtenues sur les animaux vivants (vaches et taurillons) étant ensuite comparées à des dissections anatomiques de la sixième côte sur les carcasses. Cette expérience fait ressortir la nécessité de préciser le protocole de mesure de l'échographe et de multiplier les mesures et les effectifs pour le VOS, dont l'utilisation reste réservée au domaine de la sélection

Scanning the immunopathogenesis of psoriasis

Psoriasis is a chronic inflammatory skin disease, the immunologic model of which has been profoundly revised following recent advances in the understanding of its pathophysiology. In the current model, a crosstalk between keratinocytes, neutrophils, mast cells, T cells, and dendritic cells is thought to create inflammatory and pro-proliferative circuits mediated by chemokines and cytokines. Various triggers, including recently identified autoantigens, Toll-like receptor agonists, chemerin, and thymic stromal lymphopoietin may activate the pathogenic cascade resulting in enhanced production of pro-inflammatory and proliferation-inducing mediators such as interleukin (IL)-17, tumor necrosis factor (TNF)-α, IL-23, IL-22, interferon (IFN)-α, and IFN-γ by immune cells. Among these key cytokines lie therapeutic targets for currently approved antipsoriatic therapies. This review aims to provide a comprehensive overview on the immune-mediated mechanisms characterizing the current pathogenic model of psoriasis

Analysis of Risk Factors Associated With Asymptomatic Colonization of Methicillin Resistant Staphylococcus aureus (MRSA) Among Community College Students

The bacterium Staphylococcus aureus has been an important human ailment for centuries, and with the overuse of antibiotics, methicillin resistant Staphylococcus aureus (MRSA) has emerged as a deadly, costly pathogen worldwide. Healthy carriers can become sick or can spread MRSA without symptoms. The amount of asymptomatic colonization among healthy college students and risk factors for colonization by MRSA are not well understood. According to the epidemiologic triangle model, the host (students who take antibiotics or have a history of skin infections), the infectious agent (MRSA) and the environment (direct contact with people, animals, or objects that may harbor MRSA) all play an important role in this disease. This study explored MRSA colonization rates among healthy students at a community college and explored the possibility that students exposed to sources of MRSA might have a higher colonization rate. Using a cross-sectional quantitative design with stratified sampling, risk factors to include student\u27s discipline, gender, race, work, and leisure exposure were surveyed. In tandem, Mannitol Salt Agar and MRSA Select Agar were inoculated from nasal swabs to identify students colonized by MRSA. The data were analyzed using contingency tables and Chi Squares. Significant risk factors identified included students who had a major that involved touching shared equipment and/or those who were in majors such as nursing, students who had close contact with animals, and students who had a skin infection. The implication for positive social change include improved awareness of MRSA colonization and risk factors which can lead to better prevention strategies and increased awareness among the student population

Detection of spirochaetal DNA simultaneously in skin biopsies, peripheral blood and urine from patients with erythema migrans

Lyme borreliosis is an emerging zoonosis transmitted by infected hard-bodied ticks. The disease is multisystemic. In the initial stage its typical manifestation is the erythema migrans, a cutaneous lesion that occurs in up to 90% of patients. In order to investigate the presence of the specific agent, Borrelia burgdorferi, in the early stages of the disease, DNA from skin biopsies, urine and peripheral blood of 30 patients with clinically documented erythema migrans and without apparent systemic involvement was analysed by polymerase chain reaction. Borrelia DNA in both blood and skin biopsies was detected in 23 patients, while in 9 patients it was discovered in urine and skin biopsies. These results demonstrate that Borrelia DNA is detectable systemically also in patients with early Lyme borreliosis and strongly suggest a possible dissemination of the causative agents even when only a local infection is assumed. Key words: erythema migrans; Lyme borreliosis; paraffinembedded tissues; PCR analysis

Atmospheric production of energetic protons, electrons and positrons observed in near Earth orbit

Abstract Substantial fluxes of protons and leptons with energies below the geomagnetic cutoff have been measured by the AMS experiment at altitudes of 350–390 km, in the latitude interval ±51.7°. The production mechanisms of the observed trapped fluxes are investigated in detail by means of the FLUKA Monte Carlo simulation code. All known processes involved in the interaction of the cosmic rays with the atmosphere (detailed descriptions of the magnetic field and the atmospheric density, as well as the electromagnetic and nuclear interaction processes) are included in the simulation. The results are presented and compared with experimental data, indicating good agreement with the observed fluxes. The impact of the secondary proton flux on particle production in atmosphere is briefly discussed

Protons in near earth orbit

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure

A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the $\sim 100 \mathrm{MeV}$ to $1 \mathrm{TeV}$ range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected $10^8$ cosmic ray triggers. Part of the \emph{Mir} space station was within the AMS-01 field of view during the four day \emph{Mir} docking phase of this flight. We have reconstructed an image of this part of the \emph{Mir} space station using secondary $\pi^-$ and $\mu^-$ emissions from primary cosmic rays interacting with \emph{Mir}. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor stylistic and grammer change

SHR overexpression induces the formation of supernumerary cell layers with cortex cell identity in rice

The number of root cortex cell layers varies among plants, and many species have several cortical cell layers. We recently demonstrated that the two rice orthologs of the Arabidopsis SHR gene, OsSHR1 and OsSHR2, could complement the A. thaliana shr mutant. Moreover, OsSHR1 and OsSHR2 expression in A. thaliana roots induced the formation of extra root cortical cell layers. In this article, we demonstrate that the overexpression of AtSHR and OsSHR2 in rice roots leads to plants with wide and short roots that contain a high number of extra cortical cell layers. We hypothesize that SHR genes share a conserved function in the control of cortical cell layer division and the number of ground tissue cell layers in land plants