3,400 research outputs found

    Explaining nascent entrepreneurship across countries

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    This paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship rates for 36 countries in 2002 as well as variables from standardized national statistics. The first approach relates the level of entrepreneurship of a country to its level of economic development. We found evidence for a U-shaped relationship. The second approach deals with a regime switch where the innovative advantage moves from large, established enterprises to small and new firms, because new technologies have reduced the importance of scale economies in many sectors. The third approach assumes that nascent entrepreneurship depends upon aggregate conditions such as technology, demography, culture and institutions, influencing opportunities, resources, skills and preferences. Several indicators of these aggregate conditions are found to correlate with nascent entrepreneurship. A full model combining the three approaches includes a U-shaped relationship with per capita income as well as with Porter's innovative capacity index, in addition to effects of social security expenditure (-) and the total business ownership rate (+). Finally, a (former) communist-country dummy plays an important role.

    La fragmentation des métaux fondus sous choc. Eléments de modélisation appliqués à l'étain.

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    Nous nous intéressons à un phénomène de fragmentation des métaux fondus sous choc appelé micro-écaillage. Les approches énergétiques globales fournissent un cadre général de modélisation et permettent de prédire la taille caractéristique des fragments générés. Cependant, elles n'apportent aucune information sur les mécanismes microstructuraux impliqués. Le problème micromécanique d'une sphère creuse liquide en expansion est alors présenté. Sa résolution apporte de nouveaux éléments de compréhension sur le rôle de la cavitation au cours du processus de fragmentation des liquides

    La médiation humaniste, pour ‘faire société’ dans la prise en charge des différends

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    This paper is the work of a collective, and contains multidisciplinary reflexions on a humanistic practice of mediation that was pioneered in France in 1984, and refined over 30 years of practical experience and thousands of completed mediations. This kind of mediation focuses its efforts less on the specific area of dispute, and more on the transformation of human and social relationships, thereby justifying the qualifier ‘humanistic’. The exchanges established between the mediants, made possible and facilitated by the mediator, have the core objective of rebuilding a lasting and peaceable relationship.Humanistic mediation is shown to be a tool for personal, ontological transformation – a way of supporting the deep aspirations and values which everyone needs in order to live. In social interaction it enables common ground (‘commons’) to emerge which forms the basis of a new mode of sharing; it introduces a process that is humanizing and mutually nurturing while still respecting differences. Humanistic mediation is rooted in the trans-modern beginnings of our ongoing societal transformation. By reintroducing a sense of existential solidarity which is founded more on sharing than on exchange, it offers itself as an educational tool for peace, using a civilizing pedagogy to create a humanism for our times.The process is laid out in three sequential phases, which take into account the emotions of the mediants. With often spectacular results, the process leads to a pivotal moment that allows the energy of the conflict to be redirected. The role and attitude of the mediator are precisely defined. The relationship between mediation and institutions such as justice and education is discussed. Humanistic mediation takes its place in the evolution of a justice that both repairs and restores.Cet article est la réflexion pluridisciplinaire d’un collectif sur une pratique humaniste de la médiation, introduite de façon pionnière en 1984 et affinée au cours de 30 ans d’expérience et de milliers de médiations réalisées. Ce type de médiation concentre ses efforts moins sur le différend que sur la transformation des rapports humains et sociaux, justifiant ainsi le qualificatif humaniste. Les échanges instaurés entre les médiants, rendus possibles et facilités par le médiateur, ont pour objectif essentiel de reconstruire une relation pacifiée et durable.La médiation humaniste se révèle un outil ontologique de transformation personnelle prenant appui sur les aspirations profondes et les valeurs dont chacun a besoin pour vivre. Socialement, elle permet l’émergence de communs sur lesquels fonder un nouveau mode de partage, introduisant un processus de fécondation mutuelle et d’humanisation réciproque, dans le respect des différences. La médiation humaniste s’inscrit dans les prémices trans-modernes de la transformation sociétale en cours. Réintroduisant le sens d’une solidarité existentielle, fondée plus sur le partage que sur l’échange, elle se présente comme un outil d’éducation à la paix, pédagogique et civilisateur, pour un humanisme de notre temps.Le déroulement en est explicité en trois phases successives prenant en compte les émotions des médiants et aboutissant à un retournement souvent spectaculaire qui permet de réorienter l’énergie du conflit. Le rôle et la posture du médiateur sont précisés.Le rapport aux institutions Justice et Education est discuté. La médiation humaniste s’inscrit dans une démarche de justice réparatrice et restauratrice

    Clozapine once- versus multiple-daily dosing: a two-center cross-sectional study, systematic review and meta-analysis

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    Evidence regarding effectiveness and safety of clozapine once- vs. multiple-daily dosing is limited. We compared demographic and clinical parameters between patients with once- vs. multiple-daily dosing in the Department of Psychiatry and Psychotherapy, University of Regensburg, Germany (AGATE dataset), and the Department of Psychiatry, Lausanne University Hospital, Switzerland, using non-parametric tests. Effectiveness and safety outcomes were available in the AGATE dataset. We performed a systematic review in PubMed/Embase until February 2022, meta-analyzing studies comparing clozapine once- vs. multiple-daily-dosing. We estimated a pooled odds ratio for adverse drug-induced reactions (ADRs) and meta-analyzed differences regarding clinical symptom severity, age, percentage males, smokers, clozapine dose, and co-medications between patients receiving once- vs. multiple-daily dosing. Study quality was assessed using the Newcastle–Ottawa-Scale. Of 1494 and 174 patients included in AGATE and Lausanne datasets, clozapine was prescribed multiple-daily in 74.8% and 67.8%, respectively. In the AGATE cohort, no differences were reported for the clinical symptoms severity or ADR rate (p > 0.05). Meta-analyzing eight cohorts with a total of 2810 clozapine-treated individuals, we found more severe clinical symptoms (p = 0.036), increased ADR risk (p = 0.01), higher clozapine doses (p < 0.001), more frequent co-medication with other antipsychotics (p < 0.001), benzodiazepines (p < 0.001), anticholinergics (p = 0.039), and laxatives (p < 0.001) in patients on multiple- vs. once-daily dosing. Of six studies, five were rated as good, and one as poor quality. Patients responding less well to clozapine may be prescribed higher doses multiple-daily, also treated with polypharmacy, potentially underlying worse safety outcomes. Patient preferences and adherence should be considered during regimen selection

    Filaments in the Lupus molecular clouds

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    We have studied the filaments extracted from the column density maps of the nearby Lupus 1, 3, and 4 molecular clouds, derived from photometric maps observed with the Herschel satellite. Filaments in the Lupus clouds have quite low column densities, with a median value of ∼1.5 × 1021 cm-2 and most have masses per unit length lower than the maximum critical value for radial gravitational collapse. Indeed, no evidence of filament contraction has been seen in the gas kinematics. We find that some filaments, that on average are thermally subcritical, contain dense cores that may eventually form stars. This is an indication that in the low column density regime, the critical condition for the formation of stars may be reached only locally and this condition is not a global property of the filament. Finally, in Lupus we find multiple observational evidences of the key role that the magnetic field plays in forming filaments, and determining their confinement and dynamical evolution

    Solar wind sputtering of dust on the surface of 67P/Churyumov-Gerasimenko

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    International audienceFar away from the Sun, at around 3 AU, the activity of comet 67P/Churyumov-Gerasimenko is low and changes with local time (solar insolation), with location (chemical heterogeneity of the surface), and with season. When the activity is very low because the total cross section of the comet against the Sun is small, the solar wind has access to the surface of the comet and causes ion-induced sputtering of surface material, which we wish to observe.Methods. We used the Double Focussing Mass Spectrometer (DFMS) of the ROSINA experiment on ESA’s Rosetta mission to search for mass spectrometric evidence of sputtered refractory species. In high-resolution mode, DFMS can separate some of the mass peaks of refractory elements from the many volatile species present in the coma.Results. At present, the locations of solar wind surface access are in the southern hemisphere of the comet (the local winter). Of particular interest is sputtering of dust grains on the surface. We observe global averages over the winter hemisphere of the refractory elements Na, K, Si, and Ca, presumably sputtered from grains residing on the surface. Compared to carbonaceous chondrites, the comet has the same Na abundance, is depleted in Ca, and has an excess of K. In addition, for Si the signal strength is strong enough to compile a coarse compositional map of the southern hemisphere. Most, perhaps all, of the observed variation can be explained by the solar wind being affected by the atmosphere of the comet

    Meta-GWAS Accuracy and Power (MetaGAP) Calculator Shows that Hiding Heritability Is Partially Due to Imperfect Genetic Correlations across Studies

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    Large-scale genome-wide association results are typically obtained from a fixed-effects meta-analysis of GWAS summary statistics from multiple studies spanning different regions and/or time periods. This approach averages the estimated effects of genetic variants across studies. In case genetic effects are heterogeneous across studies, the statistical power of a GWAS and the predictive accuracy of polygenic scores are attenuated, contributing to the so-called ‘missing heritability’. Here, we describe the online Meta-GWAS Accuracy and Power (MetaGAP) calculator (available at www.devlaming.eu) which quantifies this attenuation based on a novel multi-study framework. By means of simulation studies, we show that under a wide range of genetic architectures, the statistical power and predictive accuracy provided by this calculator are accurate. We compare the predictions from the MetaGAP calculator with actual results obtained in the GWAS literature. Specifically, we use genomic-relatedness-matrix restricted maximum likelihood to estimate the SNP heritability and cross-study genetic correlation of height, BMI, years of education, and self-rated health in three large samples. These estimates are used as input parameters for the MetaGAP calculator. Results from the calculator suggest that cross-study heterogeneity has led to attenuation of statistical power and predictive accuracy in recent large-scale GWAS efforts on these traits (e.g., for years of education, we estimate a relative loss of 51–62% in the number of genome-wide significant loci and a relative loss in polygenic score R2of 36–38%). Hence, cross-study heterogeneity contributes to the missing heritability

    Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub

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    We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 μm, 160 μm, 250 μm, 350 μm, and 500 μm by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Herschel Space Observatory as part of the Herschel imaging survey of OB young stellar objects (HOBYS) Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In addition, C18O data from the IRAM 30-m Telescope are presented, and used for kinematic information. Sources were extracted from the maps with getsources, and from the fluxes measured, spectral energy distributions were constructed, allowing measurements of source mass and dust temperature. Of 177 Herschel sources robustly detected in the region (a detection with high signal-to-noise and low axis ratio at multiple wavelengths), including protostars and starless cores, 29 are found in a filamentary hub at the centre of the region (a little over 1% of the observed area). These objects are on average smaller, more massive, and more luminous than those in the surrounding regions (which together suggest that they are at a later stage of evolution), a result that cannot be explained entirely by selection effects. These results suggest a picture in which the hub may have begun star formation at a point significantly earlier than the outer regions, possibly forming as a result of feedback from earlier star formation. Furthermore, the hub may be sustaining its star formation by accreting material from the surrounding filaments

    Reconstructing the density and temperature structure of prestellar cores from <i>Herschel</i> data: a case study for B68 and L1689B

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    Utilizing multiwavelength dust emission maps acquired with Herschel, we reconstruct local volume density and dust temperature profiles for the prestellar cores B68 and L1689B using an inverse-Abel transform-based technique. We present intrinsic radial dust temperature profiles of starless cores directly from dust continuum emission maps disentangling the effect of temperature variations along the line of sight, which were previously limited to the radiative transfer calculations. The reconstructed dust temperature profiles show a significant drop in the core center, a flat inner part, and a rising outward trend until the background cloud temperature is reached. The central beam-averaged dust temperatures obtained for B68 and L1689B are 9.3 ± 0.5 K and 9.8 ± 0.5 K, respectively, which are lower than the temperatures of 11.3 K and 11.6 K obtained from direct SED fitting. The best mass estimates derived by integrating the volume density profiles of B68 and L1689B are 1.6 M⊙ and 11 M⊙, respectively. Comparing our results for B68 with the near-infrared extinction studies, we find that the dust opacity law adopted by the HGBS project, κλ = 0.1 × (λ/300 μm)-2 cm2 g-1 agrees to within 50% with the dust extinction constraints
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