2,923 research outputs found

    Les entrepreneurs dans les technologies de l’information et de la communication : Proposition d’une typologie

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    MalgrĂ© la forte croissance du secteur des TIC, les recherches concernant ses spĂ©cificitĂ©s entrepreneuriales sont peu nombreuses. Or, les entrepreneurs ne constituent pas une entitĂ© homogĂšne et il est nĂ©cessaire d’élaborer des typologies pour montrer leurs diffĂ©rentes caractĂ©ristiques. Nous cherchons donc Ă  dĂ©terminer si les entrepreneurs TIC sont similaires Ă  ceux des autres secteurs et si ces derniers possĂšdent des profils diffĂ©renciĂ©s. Un Ă©chantillon composĂ© de 469 entreprises nous a permis de relever quatre profils d’entrepreneurs TIC dĂ©nommĂ©s respectivement « cadres d’expĂ©rience », « jeunes diplĂŽmĂ©s », « prĂ©voyants » et « risque-tout ».The information and communication technology sector is strategic to stakeholders in most countries, but little research exists focusing specifically on entrepreneurship in this growth industry. In particular, few findings describe the high-tech entrepreneur of this industry despite a claim for more research into specificities of and differences between entrepreneurs. This study intends to fill this gap and analyses if ICT entrepreneurs constitute rather a homogeneous entity or a type of entrepreneur displaying multiple facets and differences. To answer this questions, survey data of 469 ICT firms of the “first generation” (1993-2001) were analysed and four profiles were identified : expert, freshman, well prepared “provident”, and “risque-tout”.A pesar del fuerte crecimiento del sector de las TecnologĂ­as de informaciĂłn y de ComunicaciĂłn (TIC), las investigaciones sobre las especificadas empresariales son pocas numerosas. Ahora bien, los empresarios no constituyen una entidad homogĂ©nea y es necesario identificar las topologĂ­as para ensenar sus diferentes caracterĂ­sticas. Pues, intentamos determinar si los empresarios TIC son similares a los de otros sectores y si poseen perfiles diferenciados. Una muestra compuesta de 486 empresas nos permito identificar cuatro perfiles de empresarios TIC denominados respectivamente « ejecutivos de experiencia », « previsores », « reciĂ©n titulados sin experiencia » y « risque-tout ».Der Informations- und Kommunikationstechnologiesektor (IuK) wird weitgehend als strategischer Wachsttumssektor eingestuft, paradoxerweise liegen nur wenig entrepreneurship spezifische Studien vor die sowohl die Branche als auch den High-tech Unternehmer selbst zum Objekt haben. Obwohl die Forschungsliteratur immer wieder darauf hinweist, dass Unternehmer keine einheitlich Gruppe darstellen und sich das Unternehmerprofil von Sektor zu Sektor unterscheiden kann, sind nur wenig Studien in der Vergangenheit diesem Problem nachgegangen. Die vorliegende Studie setzt sich zum Ziel diese LĂŒcke auszufĂŒllen und analysiert den IuK Unternehmer. 469 IuK start-ups der ’ersten Generation’ (1993-2001)wurden untersucht und die Forschungsergebnisse unterscheiden vier Unternehmertypen innerhalb des Sektors : der ’Experte’, der ’Neuling’, der ’Vorsichtige’, und der ’Risque-toutunternehmer’

    A long, nontranslatable poly(A) RNA stored in the egg of the sea urchin Strongylocentrotus purpuratus

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    Nontranslatable transcripts containing interspersed repetitive sequence elements constitute a major fraction of the poly(A) RNA stored in the cytoplasm of both the sea urchin egg and the amphibian oocyte. We report the first complete sequence of a representative interspersed maternal RNA transcript, called ISp1. The transcript is about 3.7 kb in length [including poly(A) tail]; and the 5' half consists of a cluster of repetitive sequences, whereas the 3' half is single copy. Other repetitive sequences occur in the 5' and 3' regions flanking the transcription unit. In several cloned alleles, the flanking repetitive and single-copy sequences differ, indicating a high degree of insertional and deletional rearrangement around, as well as within, the transcription unit. No significant open reading frames exist in any region of the ISp1 transcript, nor is it spliced to give rise to translatable mRNA in egg or embryo. A 620-nucleotide repetitive sequence element at the 5' end of the ISp1 transcript is also represented in a large number of other long interspersed maternal poly(A) RNAs. In addition, this sequence appears in a prevalent set of small polyadenylated RNAs about 600-nucleotides in length, which disappear almost completely by the gastrula stage of development. The structural features of the ISp1 RNA uncovered in this work exclude several hypotheses of interspersed maternal poly(A) RNA origin and function

    A long, nontranslatable poly(A) RNA stored in the egg of the sea urchin Strongylocentrotus purpuratus

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    Nontranslatable transcripts containing interspersed repetitive sequence elements constitute a major fraction of the poly(A) RNA stored in the cytoplasm of both the sea urchin egg and the amphibian oocyte. We report the first complete sequence of a representative interspersed maternal RNA transcript, called ISp1. The transcript is about 3.7 kb in length [including poly(A) tail]; and the 5' half consists of a cluster of repetitive sequences, whereas the 3' half is single copy. Other repetitive sequences occur in the 5' and 3' regions flanking the transcription unit. In several cloned alleles, the flanking repetitive and single-copy sequences differ, indicating a high degree of insertional and deletional rearrangement around, as well as within, the transcription unit. No significant open reading frames exist in any region of the ISp1 transcript, nor is it spliced to give rise to translatable mRNA in egg or embryo. A 620-nucleotide repetitive sequence element at the 5' end of the ISp1 transcript is also represented in a large number of other long interspersed maternal poly(A) RNAs. In addition, this sequence appears in a prevalent set of small polyadenylated RNAs about 600-nucleotides in length, which disappear almost completely by the gastrula stage of development. The structural features of the ISp1 RNA uncovered in this work exclude several hypotheses of interspersed maternal poly(A) RNA origin and function

    Model binding experiments with cucurbit[7]uril and p-sulfonatocalix[4]arene support use of explicit solvation term in governing equation for binding equilibria

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    The thermodynamics of model host–guest-binding reactions is examined in depth using isothermal titration calorimetry. In conflict with classical thermodynamics, the results indicate that the equilibrium-binding quotient, K, is not a constant for all pairings. This outcome is predicted by an equation for binding equilibria that includes an explicit term for the change in solvation free energy that accompanies the formation of a binary complex. Application of this framework to the experimentally observed concentration dependence of K allows one to obtain the energetic contribution of the solvent, a linked equilibrium denoted here as ΔGH2O. The estimated values of ΔGH2O are large and unfavourable for the binding of selected guest molecules to two hosts, cucurbit[7]uril and p-sulfonatocalix[4]arene. Intriguingly, the estimated values of ΔGH2O are near zero for the binding of two hydrophobic guest molecules to ÎČ-cyclodextrin, leading to a thought-provoking discussion on the driving force behind the hydrophobic effect

    Campanian-Maastrichtian ocean circulation in the tropical Pacific

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    The Pacific Ocean is the largest water body on Earth, and circulation in the Pacific contributed significantly to climate evolution in the latest Cretaceous, the culmination of a period of long-term cooling. Here, we present new high-resolution late Campanian to Maastrichtian benthic and planktic foraminiferal stable isotope data and a neodymium (Nd) isotope record obtained from sedimentary ferromanganese oxide coatings of Ocean Drilling Program Hole 1210B from the tropical Pacific Ocean (Shatsky Rise). These new records resolve 13 million years in the latest Cretaceous, providing insights into changes in surface and bottom water temperatures and source regions of deep to intermediate waters covering the carbon isotope excursions of the Campanian-Maastrichtian Boundary Event (CMBE) and the Mid-Maastrichtian event (MME). Our new benthic foraminiferal ÎŽ18O and Nd isotope records together with published Nd isotope data show markedly parallel trends across the studied interval over a broad range of bathyal to abyssal water depths interpreted to reflect changes in the intensity of deep-ocean circulation in the tropical Pacific. In particular, we observe a three-million-year-long period of cooler conditions in the early Maastrichtian (72.5 to 69.5 Ma) when a concomitant change toward less radiogenic seawater Nd isotope signatures probably marks a period of enhanced admixture and northward flow of deep waters with Southern Ocean provenance. We suggest this change to have been triggered by intensified formation and convection of deep waters in the high southern latitudes, a process that weakened during the MME (69.5 to 68.5 Ma). The early Maastrichtian cold interval is closely related to the negative and positive carbon isotope trends of the CMBE and MME. The millions-of-years long duration of these carbon cycle perturbations suggests a tectonic forcing of climatic cooling, possibly related to changes in ocean basin geometry and bathymetry

    Field characterization of three-dimensional lee-side airflow patterns under offshore winds at a beach-dune system

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    Characterization of three-dimensional (3D) airflow remains elusive within a variety of environments and is particularly challenging over complex dune topography. Previous work examining airflow over and in the lee of dunes has been restricted to two-dimensional studies and has concentrated on dune shapes containing angle of repose lee sides only. However, the presence of vegetation in coastal dunes creates topographic differences and irregular shapes that interfere with flow separation at the crest and significantly modify lee-side airflow patterns and potential transport. This paper presents the first 3D field characterization of airflow patterns at the lee side of a subaerial dune. Flow information was obtained using an array of 3D ultrasonic anemometers deployed over a beach surface during seven offshore wind events. Data were used to measure cross-shore and alongshore lee-side airflow patterns using the three dimensions of the wind vector. Distances to re-attachment were similar to previous studies, but the range of transverse incident wind directions resulting in flow separation (0+/-35 degrees) was almost twice that previously reported (0+/-20 degrees). Airflow reversal took place with winds as slow as 1m s(-1). Transverse offshore winds generated areas of opposing wind directions both within the reversed zone and beyond re-attachment, contrary to consistent deflection in only one direction found in transverse desert dunes. Patterns of flow convergence-divergence have been reported in fluvial studies. However, while convergence was associated with weak reversal in fluvial settings, it appeared to be related to strong flow reversal here and could be produced by pressure differentials at the dune crest

    Prediction of Opioid-Induced Respiratory Depression on Inpatient Wards Using Continuous Capnography and Oximetry: An International Prospective, Observational Trial

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    Background: Opioid-related adverse events are a serious problem in hospitalized patients. Little is known about patients who are likely to experience opioid-induced respiratory depression events on the general care floor and may benefit from improved monitoring and early intervention. The trial objective was to derive and validate a risk prediction tool for respiratory depression in patients receiving opioids, as detected by continuous pulse oximetry and capnography monitoring. Methods: PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) was a prospective, observational trial of blinded continuous capnography and oximetry conducted at 16 sites in the United States, Europe, and Asia. Vital signs were intermittently monitored per standard of care. A total of 1335 patients receiving parenteral opioids and continuously monitored on the general care floor were included in the analysis. A respiratory depression episode was defined as respiratory rate ≀5 breaths/min (bpm), oxygen saturation ≀85%, or end-tidal carbon dioxide ≀15 or ≄60 mm Hg for ≄3 minutes; apnea episode lasting >30 seconds; or any respiratory opioid-related adverse event. A risk prediction tool was derived using a multivariable logistic regression model of 46 a priori defined risk factors with stepwise selection and was internally validated by bootstrapping. Results: One or more respiratory depression episodes were detected in 614 (46%) of 1335 general care floor patients (43% male; mean age, 58 ± 14 years) continuously monitored for a median of 24 hours (interquartile range [IQR], 17-26). A multivariable respiratory depression prediction model with area under the curve of 0.740 was developed using 5 independent variables: age ≄60 (in decades), sex, opioid naivety, sleep disorders, and chronic heart failure. The PRODIGY risk prediction tool showed significant separation between patients with and without respiratory depression (P < .001) and an odds ratio of 6.07 (95% confidence interval [CI], 4.44-8.30; P < .001) between the high- and low-risk groups. Compared to patients without respiratory depression episodes, mean hospital length of stay was 3 days longer in patients with ≄1 respiratory depression episode (10.5 ± 10.8 vs 7.7 ± 7.8 days; P < .0001) identified using continuous oximetry and capnography monitoring. Conclusions: A PRODIGY risk prediction model, derived from continuous oximetry and capnography, accurately predicts respiratory depression episodes in patients receiving opioids on the general care floor. Implementation of the PRODIGY score to determine the need for continuous monitoring may be a first step to reduce the incidence and consequences of respiratory compromise in patients receiving opioids on the general care floor

    Briefing Book for the Zeuthen Workshop

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    On Jun 18th 2004, the CERN Council, upon the initiative of its President, Prof. Enzo Iarocci, established an ad hoc scientific advisory group (the Strategy Group), to produce a draft strategy for European particle physics, which is to be considered by a special meeting of the CERN Council, to be held in Lisbon on Jul 14th 2006. There are three volumes to the Briefing Book. This first volume contains an introductory essay on particle physics, a summary of the issues discussed at the Open Symposium, and discussions of the other themes that the Strategy should address. The introductory essay on particle physics and the other themes were commissioned by the Preparatory Group. The summary of the issues discussed in the Symposium was prepared by the chairs of the sessions, the session speakers and the scientific secretaries. We acknowledge that this has been a difficult task, again on a very tight timescale, and we would like to thank all of those who have contributed to this volume

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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