141 research outputs found
Many Children Left Behind? Textbooks and Test Scores in Kenya
A randomized evaluation suggests that a program which provided official textbooks to randomly selected rural Kenyan primary schools did not increase test scores for the average student. In contrast, the previous literature suggests that textbook provision has a large impact on test scores. Disaggregating the results by students? initial academic achievement suggests a potential explanation for the lack of an overall impact. Textbooks increased scores for students with high initial academic achievement and increased the probability that the students who had made it to the selective final year of primary school would go on to secondary school. However, students with weaker academic backgrounds did not benefit from the textbooks. Many pupils could not read the textbooks, which are written in English, most students? third language. The results are consistent with the hypothesis that the Kenyan education system and curricular materials are oriented to the academically strongest students rather than to typical students. More generally, many students may be left behind in societies that combine 1) a centralized, unified education system; 2) the heterogeneity in student preparation associated with rapid expansion of education; and 3) disproportionate elite power.
Inorganic pyrophosphate generation by transforming growth factor-beta-1 is mainly dependent on ANK induction by Ras/Raf-1/extracellular signal-regulated kinase pathways in chondrocytes
ANK is a multipass transmembrane protein transporter thought to play a role in the export of intracellular inorganic pyrophosphate and so to contribute to the pathophysiology of chondrocalcinosis. As transforming growth factor-beta-1 (TGF-β1) was shown to favor calcium pyrophosphate dihydrate deposition, we investigated the contribution of ANK to the production of extracellular inorganic pyrophosphate (ePPi) by chondrocytes and the signaling pathways involved in the regulation of Ank expression by TGF-β1. Chondrocytes were exposed to 10 ng/mL of TGF-β1, and Ank expression was measured by quantitative polymerase chain reaction and Western blot. ePPi was quantified in cell supernatants. RNA silencing was used to define the respective roles of Ank and PC-1 in TGF-β1-induced ePPi generation. Finally, selective kinase inhibitors and dominant-negative/overexpression plasmid strategies were used to explore the contribution of several signaling pathways to Ank induction by TGF-β1. TGF-β1 strongly increased Ank expression at the mRNA and protein levels, as well as ePPi production. Using small interfering RNA technology, we showed that Ank contributed approximately 60% and PC-1 nearly 20% to TGF-β1-induced ePPi generation. Induction of Ank by TGF-β1 required activation of the extracellular signal-regulated kinase (ERK) pathway but not of p38-mitogen-activated protein kinase or of protein kinase A. In line with the general protein kinase C (PKC) inhibitor calphostin C, Gö6976 (a Ca2+-dependent PKC inhibitor) diminished TGF-β1-induced Ank expression by 60%, whereas a 10% inhibition was observed with rottlerin (a PKCδ inhibitor). These data suggest a regulatory role for calcium in TGF-β1-induced Ank expression. Finally, we demonstrated that the stimulatory effect of TGF-β1 on Ank expression was inhibited by the suppression of the Ras/Raf-1 pathway, while being enhanced by their constitutive activation. Transient overexpression of Smad 7, an inhibitory Smad, failed to affect the inducing effect of TGF-β1 on Ank mRNA level. These data show that TGF-β1 increases ePPi levels, mainly by the induction of the Ank gene, which requires activation of Ras, Raf-1, ERK, and Ca2+-dependent PKC pathways in chondrocytes
High interferon type I responses in the lung, plasma and spleen during highly pathogenic H5N1 infection of chicken
This study shows that high pathogenic H5N1 influenza virus infection of chicken induced high levels of bioactive interferon type I in the lung (4.3 × 105 U/mg tissue), plasma (1.1 × 105 U/mL), and spleen (9.1 × 105 U/mg tissue). In contrast, a low pathogenic attenuated H5N1 vaccine strain only induced approximately 24 times less IFN in the lung, 441 times less in the spleen and 649 less in the plasma. This was in the same range as a reassortant carrying the HA from the vaccine strain and the remaining genes from the high pathogenic virus. On the other hand, a reassortant virus with the HA from the high pathogenic H5N1 with the remaining genes from the vaccine strain had intermediate levels of IFN. The level of interferon responses related to the viral load, and those in the spleen and blood to the spread of virus to lymphoid tissue, as well as disease severity. In vitro, the viruses did not induce interferon in chicken embryonic fibroblasts, but high levels in splenocytes, with not clear relationship to pathogenicity and virulence. This, and the responses also with inactivated viruses imply the presence of plasmacytoid dendritic cell-like leukocytes within the chicken immune system, possibly responsible for the high interferon responses during H5N1 infection. Our data also indicate that the viral load as well as the cleavability of the HA enabling systemic spread of the virus are two major factors controlling systemic IFN responses in chicken
Anti-inflammatory effect of antidiabetic thiazolidinediones prevents bone resorption rather than cartilage changes in experimental polyarthritis
Contrasting effects of peroxisome-proliferator-activated receptor (PPAR)γ agonists on membrane-associated prostaglandin E(2 )synthase-1 in IL-1β-stimulated rat chondrocytes: evidence for PPARγ-independent inhibition by 15-deoxy-Δ(12,14)prostaglandin J(2)
Microsomal prostaglandin E synthase (mPGES)-1 is a newly identified inducible enzyme of the arachidonic acid cascade with a key function in prostaglandin (PG)E(2 )synthesis. We investigated the kinetics of inducible cyclo-oxygenase (COX)-2 and mPGES-1 expression with respect to the production of 6-keto-PGF(1α )and PGE(2 )in rat chondrocytes stimulated with 10 ng/ml IL-1β, and compared their modulation by peroxisome-proliferator-activated receptor (PPAR)γ agonists. Real-time PCR analysis showed that IL-1β induced COX-2 expression maximally (37-fold) at 12 hours and mPGES-1 expression maximally (68-fold) at 24 hours. Levels of 6-keto-PGF(1α )and PGE(2 )peaked 24 hours after stimulation with IL-1β; the induction of PGE(2 )was greater (11-fold versus 70-fold, respectively). The cyclopentenone 15-deoxy-Δ(12,14)prostaglandin J(2 )(15d-PGJ(2)) decreased prostaglandin synthesis in a dose-dependent manner (0.1 to 10 μM), with more potency on PGE(2 )level than on 6-keto-PGF(1α )level (-90% versus -66% at 10 μM). A high dose of 15d-PGJ(2 )partly decreased COX-2 expression but decreased mPGES-1 expression almost completely at both the mRNA and protein levels. Rosiglitazone was poorly effective on these parameters even at 10 μM. Inhibitory effects of 10 μM 15d-PGJ(2 )were neither reduced by PPARγ blockade with GW-9662 nor enhanced by PPARγ overexpression, supporting a PPARγ-independent mechanism. EMSA and TransAM(® )analyses demonstrated that mutated IκBα almost completely suppressed the stimulating effect of IL-1β on mPGES-1 expression and PGE(2 )production, whereas 15d-PGJ(2 )inhibited NF-κB transactivation. These data demonstrate the following in IL-1-stimulated rat chondrocytes: first, mPGES-1 is rate limiting for PGE(2 )synthesis; second, activation of the prostaglandin cascade requires NF-κB activation; third, 15d-PGJ(2 )strongly inhibits the synthesis of prostaglandins, in contrast with rosiglitazone; fourth, inhibition by 15d-PGJ(2 )occurs independently of PPARγ through inhibition of the NF-κB pathway; fifth, mPGES-1 is the main target of 15d-PGJ(2)
Guidelines for the diagnosis and management of chylomicron retention disease based on a review of the literature and the experience of two centers
Familial hypocholesterolemia, namely abetalipoproteinemia, hypobetalipoproteinemia and chylomicron retention disease (CRD), are rare genetic diseases that cause malnutrition, failure to thrive, growth failure and vitamin E deficiency, as well as other complications. Recently, the gene implicated in CRD was identified. The diagnosis is often delayed because symptoms are nonspecific. Treatment and follow-up remain poorly defined
Le site de hauteur des Barasses à Balazuc (Ardèche)
Le site de hauteur des Barasses, jusqu’alors absent du corpus des sites perchés protohistoriques connus en Ardèche, a fait l’objet d’une première campagne archéologique en mai 2015, dans le cadre du Projet Collectif de Recherche « L’habitat fortifié à l'âge du Bronze et au premier âge du Fer sur le versant oriental du Massif Central : départements de la Loire, de l'Ardèche et du Rhône », puis d’une seconde, de manière indépendante, en juin 2016. Une phase de prospection suivie de l’ouverture de plusieurs sondages ont permis de déterminer diverses phases d’occupations et de fréquentations de l’éperon. Une occupation pérenne de la première moitié du premier âge du Fer a pu notamment être diagnostiquée, avec la présence de bâti en matériaux légers et périssables, ainsi que de diverses preuves d’artisanat et de consommation alimentaire. La présence importante de céramique d’importation inscrit le site des Barasses dans les réseaux de circulation et d’échanges rhodanien et méditerranéen, qui se développent à la transition des deux âges du Fer.The hilltop settlement of the Barasses, until then unknown among protohistoric perched settlements in Ardèche, was first the subject of an archeological campaign in May 2015. This work was part of the Collective Research Project "The fortified settlement from the Bronze Age and the First Iron Age on the eastern slope of the Massif Central: the Departments of the Loire, Ardèche and Rhone." A second independent study followed in June 2016. A phase of prospecting followed by the opening of several excavations made it possible to determine various phases of settlement on the spur. A perennial occupation of the first half of the First Iron Age could then be diagnosed, including the presence of constructions made of light and perishable material, as well as clear evidence of craftsmanship and food consumption. The significant presence of imported ceramics places the Barasses site in the Rhone and Mediterranean circulation and exchange networks, which developed at the transition of the two Iron Ages
Physical modelling of water, fauna and flora: knowledge gaps, avenues for future research and infrastructural needs
peer reviewedPhysical modelling is a key tool for generating understanding of the complex interactions between aquatic organisms and hydraulics, which is important for management of aquatic environments under environmental change and our ability to exploit ecosystem services. Many aspects of this field remain poorly understood and the use of physical models within eco-hydraulics requires advancement in methodological application and substantive understanding. This paper presents a review of the emergent themes from a workshop tasked with identifying the future infrastructure requirements of the next generation of eco-hydraulics researchers. The identified themes are: abiotic factors, adaptation, complexity and feedback, variation, and scale and scaling. The paper examines these themes and identifies how progress on each of them is key to existing and future eðorts to progress our knowledge of eco-hydraulic interactions. Examples are drawn from studies on biofilms, plants, and sessile and mobile fauna in shallow water fluvial and marine environments. Examples of research gaps and directions for educational, infrastructural and technological advance are also presented.PISCES work package of HYDRALAB FP
Addition de carbènes aux alcynes par catalyse au ruthénium (synthèse de dérivés bicycliques d acides aminés et de diènes fonctionnalisés)
Des réactions d'addition de carbènes aux triples liaisons en présence du précatalyseur Cp*Ru(cod)Cl ont été développées. Ces transformations catalytiques ont permis d'accéder à de nouvelles molécules polyfonctionnelles par la formation de liaisons carbone-carbone. La réaction catalytique tandem de métathèse/cyclopropanation découverte au laboratoire, appliquée à des énynes dérivés d'a-aminoacides a permis d'accéder à des dérivés d'alcénylbicyclo[3.1.0]hexanes et d'alcénylbicyclo[4.1.0]heptanes. La réaction a été appliquée sur des énynes obtenus à partir de la glycine, de l'alanine et de la leucine et donne accès, en voie racémique et énantiosélective, à de nouveaux dérivés d'acides aminés bicycliques avec motif cyclopropane. La réaction catalytique tandem a été appliquée à différents 1,6-énynes et 1,7-énynes dérivés d'acides aminés fluorés et a conduit à la formation de dérivés bicyliques d'a-trifluorométhyl-a-aminoesters. L'activation d'un carbonate propargylique disubstitué en présence d'une molécule de diazoalcane a conduit à la formation de diènes conjugués fonctionnalisés par un groupement carbonate. Le diène est obtenu après une 1,2-migration du groupement carbonate sur le carbone du carbène. La réaction appliquée à des carbonates propargyliques non substitués ou mono substitués en position propargylique conduit à la formation de 1,4-bistriméthylsilyl-1,3-butadiènes divers. Les diènes sont obtenus par addition de deux molécules de diazoalcane sur la triple liaison.Addition of carbenes to alkynes in the presence of the catalyst Cp*Ru(cod)Cl has been developed. This catalytic transformation allowed to reach new polyfonctional molecules by formation of carbon-carbon bonds. Metathesis / cyclopropanation tandem reaction discovered in the laboratory has been applied to aminoacids derivatives enynes and allowed to reach alcenylbicyclo[3.1.0]hexanes and alcenylbicyclo[4.1.0]heptanes derivatives. The reaction has been applied to enynes obtained from glycine, alanine and leucine, and gived access, in racemic and enantioselective way, to bicyclic amino acids derivatives with cyclopropane moiety. The catalytic tandem reaction has been applied to different 1,6-enynes and 1,7-enynes derived of amino acids and led to the formation of bicyclic trifluoromethyl-aminoesters. The ectivation of a disubstituted propargylic carbonate in the presence of a molecule of diazoalkane led to the formation of conjugated dienes functionalized by a carbonate group. Dienes are obtained after a 1,2-migration of the carbonate group on the carbon of the carbene. This reaction applied to mono substituted or no substituted propargylic carbonates led to the formation of 1,4-bistrimethylsilyl-1,3-butadienes. These dienes were obtained by addition of two molecules of diazoalkane on the triple bond.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF
Les bon(nes) heur(e)s du grand âge :apprivoiser la vulnérabilité
info:eu-repo/semantics/nonPublishe
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