142 research outputs found

    Pitfalls in the Assessment of Postgraduate Scholarship Programs: The Need for New Indicators

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    Very few published studies have examined the outcomes of postgraduate scholarship programs. Basing our analysis on these studies and on internal reports from U.S. and Canadian organizations involved in scholarship programs, we have compiled an overview of the wide variety of indicators and methods that have been used, and conducted a comparative study of outcomes using the four most commonly used indicators: awarded diploma, obtained job, obtained related job, and pursuing studies. Our analysis revealed several methodological pitfalls in comparing the results. Although the use of available data limits the depth of a comparative analysis, our results show that scholarship programs tend to increase the rate of awarded diplomas.TreĢ€s peu d'eĢtudes publieĢes ont examineĢ les retombeĢes des programmes de bourses d'eĢtudes supeĢrieures. En fondant notre analyse sur ces eĢtudes, mais surtout sur des rapports internes d'organismes ameĢricains et canadiens, nous avons reĢpertorieĢ une varieĢteĢ des meĢthodologies et d'indicateurs utiliseĢs puis nous avons reĢaliseĢ une eĢtude comparative avec les quatre indicateurs les plus freĢquents : le taux de diploĢ‚mation, le taux d'emploi, le taux d'emploi en relation avec les eĢtudes et le taux de poursuite des eĢtudes. Notre analyse a reĢveĢleĢ plusieurs difficulteĢs meĢthodologiques dans la comparaison des reĢsultats. MalgreĢ le fait que les donneĢes disponibles limitent la porteĢe d'une analyse comparative, nos reĢsultats montrent que ces programmes favorisent l'obtention d'un diploĢ‚me

    Vascular Permeability Factor/Vascular Endothelial Growth Factor Induces Lymphangiogenesis as well as Angiogenesis

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    Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF, VEGF-A) is a multifunctional cytokine with important roles in pathological angiogenesis. Using an adenoviral vector engineered to express murine VEGF-A164, we previously investigated the steps and mechanisms by which this cytokine induced the formation of new blood vessels in adult immunodeficient mice and demonstrated that the newly formed blood vessels closely resembled those found in VEGF-Aā€“expressing tumors. We now report that, in addition to inducing angiogenesis, VEGF-A164 also induces a strong lymphangiogenic response. This finding was unanticipated because lymphangiogenesis has been thought to be mediated by other members of the VPF/VEGF family, namely, VEGF-C and VEGF-D. The new ā€œgiantā€ lymphatics generated by VEGF-A164 were structurally and functionally abnormal: greatly enlarged with incompetent valves, sluggish flow, and delayed lymph clearance. They closely resembled the large lymphatics found in lymphangiomas/lymphatic malformations, perhaps implicating VEGF-A in the pathogenesis of these lesions. Whereas the angiogenic response was maintained only as long as VEGF-A was expressed, giant lymphatics, once formed, became VEGF-A independent and persisted indefinitely, long after VEGF-A expression ceased. These findings raise the possibility that similar, abnormal lymphatics develop in other pathologies in which VEGF-A is overexpressed, e.g., malignant tumors and chronic inflammation

    Coordination of microtubule and microfilament dynamics by Drosophila Rho1, Spire, and Cappuccino

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    The actin nucleation factors Spire and Cappuccino regulate the onset of ooplasmic streaming in Drosophila1-5. Although this streaming event is microtubule-based, actin assembly is required for its timing. It is not understood how the interaction of microtubules and microfilaments is mediated in this context. Here we demonstrate that Cappuccino and Spire have microtubule and microfilament crosslinking activity. The spire locus encodes several distinct protein isoforms (SpireA, SpireC, and SpireD). SpireD was recently shown to nucleate actin, but the activity of the other isoforms has not been addressed. We find that SpireD does not have crosslinking activity, while SpireC is a potent crosslinker. We show that SpireD binds to Cappuccino and inhibits Factin/ microtubule crosslinking, and activated Rho1 abolishes this inhibition, establishing a mechanistic basis for the regulation of Capu and Spire activity. We propose that Rho1, cappuccino and spire are elements of a conserved developmental cassette that is capable of directly mediating crosstalk between microtubules and microfilaments

    Functional dissection of the Drosophila Kallmann's syndrome protein DmKal-1

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    BACKGROUND: Anosmin-1, the protein implicated in the X-linked Kallmann's syndrome, plays a role in axon outgrowth and branching but also in epithelial morphogenesis. The molecular mechanism of its action is, however, widely unknown. Anosmin-1 is an extracellular protein which contains a cysteine-rich region, a whey acidic protein (WAP) domain homologous to some serine protease inhibitors, and four fibronectin-like type III (FnIII) repeats. Drosophila melanogaster Kal-1 (DmKal-1) has the same protein structure with minor differences, the most important of which is the presence of only two FnIII repeats and a C-terminal region showing a low similarity with the third and the fourth human FnIII repeats. We present a structure-function analysis of the different DmKal-1 domains, including a predicted heparan-sulfate binding site. RESULTS: This study was performed overexpressing wild type DmKal-1 and a series of deletion and point mutation proteins in two different tissues: the cephalopharyngeal skeleton of the embryo and the wing disc. The overexpression of DmKal-1 in the cephalopharyngeal skeleton induced dosage-sensitive structural defects, and we used these phenotypes to perform a structure-function dissection of the protein domains. The reproduction of two deletions found in Kallmann's Syndrome patients determined a complete loss of function, whereas point mutations induced only minor alterations in the activity of the protein. Overexpression of the mutant proteins in the wing disc reveals that the functional relevance of the different DmKal-1 domains is dependent on the extracellular context. CONCLUSION: We suggest that the role played by the various protein domains differs in different extracellular contexts. This might explain why the same mutation analyzed in different tissues or in different cell culture lines often gives opposite phenotypes. These analyses also suggest that the FnIII repeats have a main and specific role, while the WAP domain might have only a modulator role, strictly connected to that of the fibronectins

    Desynchronization of Neocortical Networks by Asynchronous Release of GABA at Autaptic and Synaptic Contacts from Fast-Spiking Interneurons

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    An activity-dependent long-lasting asynchronous release of GABA from identified fast-spiking inhibitory neurons in the neocortex can impair the reliability and temporal precision of activity in a cortical network

    A Motor Function for the DEAD-Box RNA Helicase, Gemin3, in Drosophila

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    The survival motor neuron (SMN) protein, the determining factor for spinal muscular atrophy (SMA), is complexed with a group of proteins in human cells. Gemin3 is the only RNA helicase in the SMN complex. Here, we report the identification of Drosophila melanogaster Gemin3 and investigate its function in vivo. Like in vertebrates, Gemin3 physically interacts with SMN in Drosophila. Loss of function of gemin3 results in lethality at larval and/or prepupal stages. Before they die, gemin3 mutant larvae exhibit declined mobility and expanded neuromuscular junctions. Expression of a dominant-negative transgene and knockdown of Gemin3 in mesoderm cause lethality. A less severe Gemin3 disruption in developing muscles leads to flightless adults and flight muscle degeneration. Our findings suggest that Drosophila Gemin3 is required for larval development and motor function

    Cell Typeā€“dependent Requirement for PIP Boxā€“regulated Cdt1 Destruction During S Phase

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    Previous studies have shown that Cdt1 overexpression in cultured cells can trigger re-replication, but not whether CRL4Cdt2-triggered destruction of Cdt1 is required for normal mitotic cell cycle progression in vivo. We demonstrate that PIP boxā€“mediated destruction of Cdt1Dup during S phase is necessary for the cell division cycle in Drosophila

    The HTAP_v3 emission mosaic: merging regional and global monthly emissions (2000ā€“2018) to support air quality modelling and policies

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    This study, performed under the umbrella of the Task Force on Hemispheric Transport of Air Pollution (TF-HTAP), responds to the global and regional atmospheric modelling community's need of a mosaic emission inventory of air pollutants that conforms to specific requirements: global coverage, long time series, spatially distributed emissions with high time resolution, and a high sectoral resolution. The mosaic approach of integrating official regional emission inventories based on locally reported data, with a global inventory based on a globally consistent methodology, allows modellers to perform simulations of high scientific quality while also ensuring that the results remain relevant to policymakers. HTAP-v3, an ad hoc global mosaic of anthropogenic inventories, has been developed by integrating official inventories over specific areas (North America, Europe, Asia including Japan and South Korea) with the independent Emissions Database for Global Atmospheric Research (EDGAR) inventory for the remaining world regions. The results are spatially and temporally distributed emissions of SO2, NOx, CO, non-methane volatile organic compounds (NMVOCs), NH3, PM10, PM2.5, black carbon (BC), and organic carbon (OC), with a spatial resolution of 0.1Ā° Ɨ 0.1Ā° and time intervals of months and years, covering the period 2000-2018 (10.5281/zenodo.7516361, Crippa, 2023, https://edgar.jrc.ec.europa.eu/dataset-htap-v3, last access: June 2023). The emissions are further disaggregated into 16 anthropogenic emitting sectors. This paper describes the methodology applied to develop such an emission mosaic, reports on source allocation, differences among existing inventories, and best practices for the mosaic compilation. One of the key strengths of the HTAP-v3 emission mosaic is its temporal coverage, enabling the analysis of emission trends over the past 2 decades. The development of a global emission mosaic over such long time series represents a unique product for global air quality modelling and for better-informed policymaking, reflecting the community effort expended by the TF-HTAP to disentangle the complexity of transboundary transport of air pollution
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