2,041 research outputs found

    Design study for LANDSAT D attitude control system

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    A design and performance evaluation is presented for the LANDSAT D attitude control system (ACS). Control and configuration of the gimballed Ku-band antenna system for communication with the tracking and data relay satellite (TDRS). Control of the solar array drive considered part of the ACS is also addressed

    Design study for LANDSAT-D attitude control system

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    The gimballed Ku-band antenna system for communication with TDRS was studied. By means of an error analysis it was demonstrated that the antenna cannot be open loop pointed to TDRS by an onboard programmer, but that an autotrack system was required. After some tradeoffs, a two-axis, azimuth-elevation type gimbal configuration was recommended for the antenna. It is shown that gimbal lock only occurs when LANDSAT-D is over water where a temporary loss of the communication link to TDRS is of no consequence. A preliminary gimbal control system design is also presented. A digital computer program was written that computes antenna gimbal angle profiles, assesses percent antenna beam interference with the solar array, and determines whether the spacecraft is over land or water, a lighted earth or a dark earth, and whether the spacecraft is in eclipse

    Détection et Reconnaissance des Gestes Emblématiques

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    Session "Atelier IHMA"National audienceDans cette contribution, nous présentons un système de reconnaissance en ligne de gestes emblématiques et son utilisation pour le contrôle d'un robot mobile. Ce système comporte quatre sous-systèmes : un premier qui permet de détecter la personne et d'extraire les mouvements de la partie supérieure de cette personne. Un second, permet d'isoler les mouvements, une troisième permet de reconnaître un des mouvements appris a priori. Enfin le dernier module, traduit les mouvements reconnus en termes de contrôle d'un robot mobile à roues. Dans notre approche, nous avons surtout traité du problème de la généralisation : faire l'apprentissage sur une base réduite de personnes et utiliser cette connaissance pour reconnaître n'importe quelle personne, indépendamment de sa morphologie, de son âge, de son sexe et de son positionnement par rapport au capteur. Nous détaillons les résultats obtenus pour la reconnaissance ainsi que l'utilisation du système dans des scenarios de contrôle d'un robot

    Sulphur-bearing molecules in diffuse molecular clouds: new results from SOFIA/GREAT and the IRAM 30 m telescope

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    We have observed five sulphur-bearing molecules in foreground diffuse molecular clouds lying along the sight-lines to five bright continuum sources. We have used the GREAT instrument on SOFIA to observe the 1383 GHz 2Π3/2J=5/2−3/2^2\Pi_{3/2} J=5/2-3/2 transitions of SH towards the star-forming regions W31C, G29.96-0.02, G34.3+0.1, W49N and W51, detecting foreground absorption towards all five sources; and the EMIR receivers on the IRAM 30m telescope at Pico Veleta to detect the H2_2S 1(10)-1(01), CS J=2-1 and SO 3(2)-2(1) transitions. In nine foreground absorption components detected towards these sources, the inferred column densities of the four detected molecules showed relatively constant ratios, with N(SH)/N(H2_2S) in the range 1.1 - 3.0, N(CS)/N(H2_2S) in the range 0.32 - 0.61, and N(SO)/N(H2_2S) in the range 0.08 - 0.30. The observed SH/H2_2 ratios - in the range (0.5-2.6) ×10−8\times 10^{-8} - indicate that SH (and other sulphur-bearing molecules) account for << 1% of the gas-phase sulphur nuclei. The observed abundances of sulphur-bearing molecules, however, greatly exceed those predicted by standard models of cold diffuse molecular clouds, providing further evidence for the enhancement of endothermic reaction rates by elevated temperatures or ion-neutral drift. We have considered the observed abundance ratios in the context of shock and turbulent dissipation region (TDR) models. Using the TDR model, we find that the turbulent energy available at large scale in the diffuse ISM is sufficient to explain the observed column densities of SH and CS. Standard shock and TDR models, however, fail to reproduce the column densities of H2_2S and SO by a factor of about 10; more elaborate shock models - in which account is taken of the velocity drift, relative to H2_2, of SH molecules produced by the dissociative recombination of H3_3S+^+ - reduce this discrepancy to a factor ~ 3.Comment: 30 pages, accepted for publication in A&

    Intramammary infections in lactating Jersey cows: Prevalence of microbial organisms and association with milk somatic cell count and persistence of infection.

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    There is limited data available regarding pathogens causing intramammary infections (IMI) in Jersey cows. The objectives of this study were to characterize the prevalence of IMI caused by different microorganisms in lactating Jersey cattle and evaluate the associations among microbes and somatic cell count (SCC) and persistence of IMI. This prospective, observational, longitudinal study included lactating Jersey cows (n = 753) from 4 farms within a 250-mile radius of Columbia, Missouri. Quarter foremilk samples were aseptically collected monthly for 3 consecutive months. Microorganisms were identified using aerobic milk culture and MALDI-TOF mass spectrometry. A commercial laboratory measured SCC using flow cytometry. Milk culture results were used to classify single microorganism infections as persistent (same microorganism species identified at first sampling and one other sampling) or non-persistent infection. Mixed models were built to evaluate the associations between IMI status and lnSCC as well as persistence and lnSCC. Overall, staphylococci were the most commonly isolated microorganisms among the 7,370 quarter-level milk samples collected. Median prevalence (using all 3 samplings) of specific microbes varied among farms; however, Staphylococcus chromogenes was a common species found at all farms. The most common microbial species that persisted were Staph. chromogenes, Staphylococcus aureus, Staphylococcus simulans, and Streptococcus uberis. Streptococcus dysgalactiae and Staph. aureus were the IMI associated with the most inflammation based on lnSCC. The small number of herds included in this study with the large variation in herd type limits the generalizability of the data. However, results of this study seem to be similar to those of previous studies in other breeds, suggesting management factors are more important than breed-specific differences when evaluating causes of IMI and associated subclinical mastitis

    Management of radiation dermatitis in patients receiving cetuximab and radiotherapy for locally advanced squamous cell carcinoma of the head and neck: proposals for a revised grading system and consensus management guidelines

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    Background: Radiation dermatitis developing in patients receiving cetuximab concomitantly with radiotherapy for locally advanced squamous cell carcinoma of the head and neck (LA SCCHN) is now recognized to have different pathophysiological and clinical characteristics to the radiation dermatitis associated with radiotherapy or concomitant chemotherapy and radiotherapy. Current grading tools were not designed to grade this type of radiation dermatitis; their use may lead to misclassification of reactions and inappropriate management strategies, potentially compromising cancer treatment. Patients and methods: An advisory board of seven leading European specialists (three medical oncologists, three radiation oncologists and a dermatologist) with extensive experience of the use of cetuximab plus radiotherapy produced consensus guidelines for the grading and management of radiation dermatitis in patients receiving cetuximab plus radiotherapy. Results: Modifications to the current, commonly used National Cancer Institute—Common Terminology Criteria for Adverse Events version 4.3 for grading radiation dermatitis were proposed. Updated management guidelines, building on previously published guidelines from 2008, were also proposed. Conclusions: The proposed revisions to the grading system and updated management guidelines described here represent important developments toward the more appropriate grading and effective management of radiation dermatitis in patients receiving cetuximab plus radiotherapy for LA SCCH
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