Exploitation des leçons d’éducation physique et sportive :: temps effectif des élèves en mouvement

Pour ce travail de Bachelor, j’ai décidé de traiter la thématique du temps effectif durant lequel les élèves sont en mouvement lors des leçons d’éducation physique et sportive. Pour cela, j’ai choisi de me focaliser sur quatre classes d’un même village du Jura bernois, une dans chaque demi-cycle, dans le but d’avoir un plus large aperçu du cursus primaire. L’objectif de mon travail de recherche est de voir durant combien de temps les élèves sont réellement en mouvement lors d’une leçon de deux périodes d’éducation physique et sportive, sachant que plusieurs minutes de la leçon sont consacrées aux consignes ainsi qu’à l’installation/rangement du matériel. Je débute mon travail en expliquant les raisons qui m’ont amenée à traiter cette thématique. À la suite de cela, je fais l’état de la question, je définis les termes de « mouvement » ainsi que temps « effectif » et j’aborde divers aspects théoriques tout en faisant référence à plusieurs auteurs. Dans une deuxième partie, j’explique les moyens utilisés pour récolter les données. Et pour terminer, j’analyse les données récoltées lors d’observation de leçons d’éducation physique et sportive ainsi que d’entretiens semi-directifs avec les enseignants. Cette dernière partie permet de mettre en évidence les similitudes et différences entre les deux cycles et les quatre degrés

Codon 215 Mutations in Human Immunodeficiency Virus—Infected Pregnant Women

In 1994, the Pediatric AIDS Clinical Trials Group (PACTG) Protocol 076 demonstrated a two-thirds reduction of perinatal human immunodeficiency virus (HIV) type 1 transmission with zidovudine chemoprophylaxis. However, zidovudine alone does not fully suppress HIV replication, and chemoprophylaxis with zidovudine alone might select for zidovudine-resistant viral variants, decreasing the efficacy of zidovudine prophylaxis and affecting future responses to combined antiretroviral regimens. Sixty-two HIV-infected pregnant women consecutively enrolled in the ongoing Swiss HIV and Pregnancy Study were prospectively evaluated for the presence or development of zidovudine resistance by analysis of codon 215 of the reverse transcriptase gene. Six women (9.6%) harbored a codon T215Y/F mutation, which is associated with high-level resistance to zidovudine. Postnatal evaluation was completed in all children of mothers harboring the mutation. None was HIV-infected. The observed prevalence of codon 215 mutations of 9.6% raises important concerns regarding the future use of the PACTG 076 regime

High Velocity Dispersion in A Rare Grand Design Spiral Galaxy at Redshift z=2.18

Although relatively common in the local Universe, only one grand-design spiral galaxy has been spectroscopically confirmed to lie at z>2 (HDFX 28; z=2.011), and may prove to be a major merger that simply resembles a spiral in projection. The rarity of spirals has been explained as a result of disks being dynamically 'hot' at z>2 which may instead favor the formation of commonly-observed clumpy structures. Alternatively, current instrumentation may simply not be sensitive enough to detect spiral structures comparable to those in the modern Universe. At redshifts <2, the velocity dispersion of disks decreases, and spiral galaxies are more numerous by z~1. Here we report observations of the grand design spiral galaxy Q2343-BX442 at z=2.18. Spectroscopy of ionized gas shows that the disk is dynamically hot, implying an uncertain origin for the spiral structure. The kinematics of the galaxy are consistent with a thick disk undergoing a minor merger, which can drive the formation of short-lived spiral structure. A duty cycle of < 100 Myr for such tidally-induced spiral structure in a hot massive disk is consistent with their rarity.Comment: Accepted for publication in Nature (July 19 2012). Includes 15-page supplemen

Spondylarthropathies (including psoriatic arthritis): 244. Validity of Colour Doppler and Spectral Doppler Ultrasound of Sacroilicac Joints Againts Physical Examination as Gold Standard

Background: Sacroiliac joints (SJ) involvement is a distinctive and charasteristic feature of Spondyloarthritis (SpA) and x-ray is the test routinely used to make a diagnosis. However, x-ray reveals late structural damage but cannot detect active inflammation. The objective of this study was to assess the validity of Doppler ultrasound in SJ. Methods: Prospective blinded and controlled study of SJ, in which three populations were compared. We studied 106 consecutive cases, who were divided into three groups: a) 53 patients diagnosed with SpA who had inflammatory lumbar and gluteal pain assessed by a rheumatologist; b) 26 patients diagnosed with SpA who didn't have SJ tenderness and had normal physical examination; c) control group of 27 subjects (healthy subjetcs or with mechanical lumbar pain). All patients included that were diagnosed with SpA met almost the European Spondyloarthropathy Study Group (ESSG) classification criteria. Physical examination of the SJ included: sacral sulcus tenderness, iliac gapping, iliac compression, midline sacral thrust test, Gaenslen's test, and Patrick s test were used as gold standard. Both SJ were examined with Doppler ultrasound (General Electric Logiq 9, Wauwatosa WI, USA) fitted with a 9-14 Mhz lineal probe. The ultrasonographer was blinded to clinical data. Doppler in SJ was assessed as positive when both Doppler colour and resistance index (RI) < 0.75 within the SJ area were present. Statistical analysis was performed estimating sensitivity and specificity against gold standard. The Kappa correlation coefficient was used for reliability study. Results: 106 cases (53 female, 55 male; mean age 36 10 years) were studied. There were no statistical differences between groups related to age or sex. Physical examination of SJ was positive in 38 patients (59 sacroiliac joints). US detected Doppler signal within SJ in 37 patients (58 SJ): 33 of them were symptomatic SpA (52 SJ), one of them were asymptomatic SpA (1 SJ) and one was a healthy control (1 SJ). The accuracy of US when compared to clinical data as gold standard at subject level in the overall group was: sensitivity of 68.6% and specificity of 85.7%, positive predictive value of 70.5% and negative predictive value of 84.5%. A positive likelihood ratio of 4.8, a negative likelihood ratio of 0.36 and a kappa coefficient of 0.55 were achieved. Conclusions: Doppler US of SJ seems to be a valid method to detect active SJ inflammation. Disclosure statement: The authors have declared no conflicts of interes

Concept-of-operations disposal analysis of spacecraft by gossamer structure

A gossamer structure for end-of-life disposal of spacecraft to mitigate space debris is considered in comparison with other end-of-life disposal concepts to determine when it would be preferable. A needs analysis, potential use cases, and concept-of-operations are developed. A survey of disposal strategies is presented for comparison prior to a down-selection of viable competing techniques; solar sailing, high and low-thrust propulsion, and electrodynamic tethers. A parametric comparison of the down-selection competing techniques is presented. Exploiting solar radiation pressure on the structure is of limited value. Atmospheric drag augmentation was found to be of most benefit for end-of-life disposal when an entirely passive means is required, allowing the gossamer device to act as a ‘fail-safe’. This is applicable to only low and medium mass spacecraft, or spacecraft that are unlikely to survive atmospheric re-entry, hence minimizing risk to human life. It does not significantly alter the operating ceiling altitude but does the maximum allowable end-of-life mass. Peak mass benefit occurs in the altitude range 550 – 650 km and is largely independent of de-orbit time

Consequences of the 2019 Greenland Ice Sheet Melt Episode on Albedo

In mid-June 2019, the Greenland ice sheet (GrIS) experienced an extreme early-season melt event. This, coupled with an earlier-than-average melt onset and low prior winter snowfall over western Greenland, led to a rapid decrease in surface albedo and greater solar energy absorption over the melt season. The 2019 melt season resulted in significantly more melt than other recent years, even compared to exceptional melt years previously identified in the moderate-resolution imaging spectroradiometer (MODIS) record. The increased solar radiation absorbance in 2019 warmed the surface and increased the rate of meltwater production. We use two decades of satellite-derived albedo from the MODIS MCD43 record to show a significant and extended decrease in albedo in Greenland during 2019. This decrease, early in the melt season and continuing during peak summer insolation, caused increased radiative forcing of the ice sheet of 2.33 Wm−2 for 2019. Radiative forcing is strongly influenced by the dramatic seasonal differences in surface albedo experienced by any location experiencing persistent and seasonal snow-cover. We also illustrate the utility of the newly developed Landsat-8 albedo product for better capturing the detailed spatial heterogeneity of the landscape, leading to a more refined representation of the surface energy budget. While the MCD43 data accurately capture the albedo for a given 500 m pixel, the higher spatial resolution 30 m Landsat-8 albedos more fully represent the detailed landscape variations

Investigating Multicomponent Approaches for the Site-Selective Conjugation of Native Proteins

Site-selective modification of proteins has been the object of intense studies over the past decades, especially in the therapeutic field. Prominent results have been obtained with recombinant proteins, for which site-specific conjugation is made possible by the incorporation of particular amino acid residues or peptide sequences. While mutant proteins take most of the spotlight, native and natural proteins have been left in the shadow and site-selective methods to conjugate these are underexplored. In addition, while these few methods give good results on small to medium-sized proteins, most of them tend to fall short whenever applied to bigger constructs such as antibodies. To address this limitation, we reasoned that aiming at the simultaneous conjugation of two amino acid residues should give higher chances of developing a site-selective strategy compared to the large majority of existing methods that solely target a single residue. We opted for the Ugi four-center three-component reaction to implement this idea, with the aim of conjugating the side-chain amine and carboxylate groups of two neighbouring lysine and aspartate/glutamate. Herein, we show that this strategy can give access to valuable conjugates bearing several different payloads, and limits the potential conjugation sites to only six on the model antibody trastuzumab

Evidence for a novel cranial thermoregulatory pathway in thalattosuchian crocodylomorphs

Thalattosuchian crocodylomorphs were a diverse clade that lived from the Early Jurassic to the Early Cretaceous. The subclade Metriorhynchoidea underwent a remarkable transition, evolving from semi-aquatic ambush predators into fully aquatic forms living in the open oceans. Thalattosuchians share a peculiar palatal morphology with semi-aquatic and aquatic fossil cetaceans: paired anteroposteriorly aligned grooves along the palatal surface of the bony secondary palate. In extant cetaceans, these grooves are continuous with the greater palatine artery foramina, arteries that supply their oral thermoregulatory structures. Herein, we investigate the origins of thalattosuchian palatal grooves by examining CT scans of six thalattosuchian species (one teleosauroid, two early-diverging metriorhynchoids and three metriorhynchids), and CT scans of eleven extant crocodylian species. All thalattosuchians had paired osseous canals, enclosed by the palatines, that connect the nasal cavity to the oral cavity. These osseous canals open into the oral cavity via foramina at the posterior terminus of the palatal grooves. Extant crocodylians lack both the external grooves and the internal canals. We posit that in thalattosuchians these novel palatal canals transmitted hypertrophied medial nasal vessels (artery and vein), creating a novel heat exchange pathway connecting the palatal vascular plexus to the endocranial region. Given the general hypertrophy of thalattosuchian cephalic vasculature, and their increased blood flow and volume, thalattosuchians would have required a more extensive suite of thermoregulatory pathways to maintain stable temperatures for their neurosensory tissues.Fil: Young, Mark T.. LWL-Museum für Naturkunde; Alemania. University of Edinburgh; Reino UnidoFil: Bowman, Charlotte I. W.. University of Edinburgh; Reino UnidoFil: Erb, Arthur. University of Edinburgh; Reino UnidoFil: Schwab, Julia A.. University of Edinburgh; Reino Unido. University of Manchester; Reino UnidoFil: Witmer, Lawrence. Ohio University; Estados UnidosFil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Brusatte, Stephen L.. University of Edinburgh; Reino Unid

Evidence for a novel cranial thermoregulatory pathway in thalattosuchian crocodylomorphs

Thalattosuchian crocodylomorphs were a diverse clade that lived from the Early Jurassic to the Early Cretaceous. The subclade Metriorhynchoidea underwent a remarkable transition, evolving from semi-aquatic ambush predators into fully aquatic forms living in the open oceans. Thalattosuchians share a peculiar palatal morphology with semi-aquatic and aquatic fossil cetaceans: paired anteroposteriorly aligned grooves along the palatal surface of the bony secondary palate. In extant cetaceans, these grooves are continuous with the greater palatine artery foramina, arteries that supply their oral thermoregulatory structures. Herein, we investigate the origins of thalattosuchian palatal grooves by examining CT scans of six thalattosuchian species (one teleosauroid, two early-diverging metriorhynchoids and three metriorhynchids), and CT scans of eleven extant crocodylian species. All thalattosuchians had paired osseous canals, enclosed by the palatines, that connect the nasal cavity to the oral cavity. These osseous canals open into the oral cavity via foramina at the posterior terminus of the palatal grooves. Extant crocodylians lack both the external grooves and the internal canals. We posit that in thalattosuchians these novel palatal canals transmitted hypertrophied medial nasal vessels (artery and vein), creating a novel heat exchange pathway connecting the palatal vascular plexus to the endocranial region. Given the general hypertrophy of thalattosuchian cephalic vasculature, and their increased blood flow and volume, thalattosuchians would have required a more extensive suite of thermoregulatory pathways to maintain stable temperatures for their neurosensory tissues