977 resultados para stimulated emission cross-section-


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OBJECTIVE: To investigate whether better management of chronic conditions by family practices reduces mortality risk. DATA: Two random samples of 5 million patients registered with over 8,000 English family practices followed up for 4 years (2004/5-2007/8). Measures of the quality of disease management for 10 conditions were constructed for each family practice for each year. The outcome measure was an indicator taking the value 1 if the patient died during a specified year, 0 otherwise. STUDY DESIGN: Cross-section and multilevel panel data multiple logistic regressions were estimated. Covariates included age, gender, morbidity, hospitalizations, attributed socio-economic characteristics, and local health care supply measures. PRINCIPAL FINDINGS: Although a composite measure of the quality of disease management for all 10 conditions was significantly associated with lower mortality, only the quality of stroke care was significant when all 10 quality measures were entered in the regression. CONCLUSIONS: The panel data results suggest that a 1 percent improvement in the quality of stroke care could reduce the annual number of deaths in England by 782 [95 percent CI: 423, 1140]. A longer study period may be necessary to detect any mortality impact of better management of other conditions.

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The aim of this work is to study flow properties at T-junction of pipe, pressure loss suffered by the flow after passing through T-junction and to study reliability of the classical engineering formulas used to find head loss for T-junction of pipes. In this we have compared our results with CFD software packages with classical formula and made an attempt to determine accuracy of the classical formulas. In this work we have studies head loss in T-junction of pipes with various inlet velocities, head loss in T-junction of pipes when the angle of the junction is slightly different from 90 degrees and T-junction with different area of cross-section of the main pipe and branch pipe. In this work we have simulated the flow at T-junction of pipe with FLUENT and Comsol Multiphysics and observed flow properties inside the T-junction and studied the head loss suffered by fluid flow after passing through the junction. We have also compared pressure (head) losses obtained by classical formulas by A. Vazsonyi and Andrew Gardel and formulas obtained by assuming T-junction as combination of other pipe components and observations obtained from software experiments. One of the purposes of this study is also to study change in pressure loss with change in angle of T-junction. Using software we can have better view of flow inside the junction and study turbulence, kinetic energy, pressure loss etc. Such simulations save a lot of time and can be performed without actually doing the experiment. There were no real life experiments made, the results obtained completely rely on accuracy of software and numerical methods used.

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We present the results of stereoscopic observations of the satellite galaxy Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. With almost 160 hours of good-quality data, this is the deepest observational campaign on any dwarf galaxy performed so far in the very high energy range of the electromagnetic spectrum. We search this large data sample for signals of dark matter particles in the mass range between 100 GeV and 20 TeV. For this we use the full likelihood analysis method, which provides optimal sensitivity to characteristic gamma-ray spectral features, like those expected from dark matter annihilation or decay. In particular, we focus our search on gamma-rays produced from different final state Standard Model particles, annihilation with internal bremsstrahlung, monochromatic lines and box-shaped signals. Our results represent the most stringent constraints to the annihilation cross-section or decay lifetime obtained from observations of satellite galaxies, for masses above few hundred GeV. In particular, our strongest limit (95% confidence level) corresponds to a ~ 500 GeV dark matter particle annihilating into τ+τ−, and is of order langleσannvrangle simeq 1.2 × 10−24 cm3 s−1 a factor ~ 40 above the langleσannvrangle simeq thermal value.

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We provide robust and compelling evidence of the marked impact of tertiary education on the economic growth of less developed countries and of its the relatively smaller impact on the growth of developed ones. Our results argue in favor of the accumulation of high skill levels especially in technologically under-developed countries and, contrary to common wisdom, independently of the fact that these economies might initially produce lower-technology goods or perform technology imitation. Our results are robust to the different measures used in proxying human capital and to the adjustments made for cross-country differences in the quality of education. Country-specific institutional quality, as well as other indicators including legal origin, religious fractionalization and openness to trade have been used to control for the robustness of the results. These factors are also shown to speed up technology convergence thereby confirming previous empirical studies. Our estimates tackle problems of endogeneity by adopting a variety of techniques, including instrumental variables -for both panel and cross-section analyses- and the two-step efficient dynamics system GMM.

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GDP has usually been used as a proxy for human well-being. Nevertheless, other social aspects should also be considered, such as life expectancy, infant mortality, educational enrolment and crime issues. With this paper we investigate not only economic convergence but also social convergence between regions in a developing country, Colombia, in the period 1975-2005. We consider several techniques in our analysis: sigma convergence, stochastic kernel estimations, and also several empirical models to find out the beta convergence parameter (cross section and panel estimates, with and without spatial dependence). The main results confirm that we can talk about convergence in Colombia in key social variables, although not in the classic economic variable, GDP per capita. We have also found that spatial autocorrelation reinforces convergence processes through deepening market and social factors, while isolation condemns regions to nonconvergence.

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In radionuclide metrology, Monte Carlo (MC) simulation is widely used to compute parameters associated with primary measurements or calibration factors. Although MC methods are used to estimate uncertainties, the uncertainty associated with radiation transport in MC calculations is usually difficult to estimate. Counting statistics is the most obvious component of MC uncertainty and has to be checked carefully, particularly when variance reduction is used. However, in most cases fluctuations associated with counting statistics can be reduced using sufficient computing power. Cross-section data have intrinsic uncertainties that induce correlations when apparently independent codes are compared. Their effect on the uncertainty of the estimated parameter is difficult to determine and varies widely from case to case. Finally, the most significant uncertainty component for radionuclide applications is usually that associated with the detector geometry. Recent 2D and 3D x-ray imaging tools may be utilized, but comparison with experimental data as well as adjustments of parameters are usually inevitable.

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In Tanzania computer knowledge is vital to supplement the pace fast growing economic and development activities, which demands high and reliable level of expertise in com- puting field. In 2006, a research carried out at Tumaini University with purpose to design and implement a contextualized curriculum that can supplement for such needs hence facilitate development in Tanzanian context. A contextualized curriculum took advantage of six principles namely curriculum contex- tualization, projects, practical, interdisciplinary orientation, international recognition and continuous research for the program’s formative and development. Implementation of the curriculum followed the CATI (Contextualize, Apply, Transfer, and Import) model with emphasis on students to identify societal expectations at the early stage in learning process, in which case the graduates will potentially cater for societal expertise needs on ICT. This study adopts an emergent exploratory cross-section research design, while employ- ing a qualitative approach. This study was conducted at Tumaini University in Iringa where by purposeful sampling was used to obtain participants such as students, teach- ers, administrators and employers who participated in several focus group discussions, in-depth interviews and participant observation. The study reveals that six principles are satisfactorily met,despite of bottlenecks such as incompatibility in pedagogical thinking and technology availability for e-learning, learning attitudes, insufficient experts with actual skills and experience,in academic field among the others. The study recommends that iterative longitudinal study should be car- ried out to design for proper intervention in response to these problems which will help in improving and stabilize the curriculum.

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Objeto: El desempeño de las actividades de servicios de alto valor añadido ofrecidospor las empresas manufactureras, de la misma forma que el de los servicios intensivosen conocimiento, puede verse afectado por las formas de contratación de la mano deobra utilizadas en ellas. Se estudia el impacto del uso de trabajo contingente (temporal y autónomo) sobre la productividad del trabajo en las empresas de servicios intensivos en conocimiento. Para desarrollar las hipótesis, se tiene en cuenta el impacto potencial del trabajo contingente sobre el capital intangible de la empresa, así como los resultados de la literatura empírica.Diseño/metodología: Se analizan los datos de una muestra de 279 empresas de servicios intensivos en conocimiento localizadas en Cataluña, mediante dos modelos de regresión lineal.Aportaciones y resultados: Los resultados muestran que el empleo de formas de trabajo contingentes, como el trabajo temporal y los trabajadores autónomos, tiene un impacto negativo en la productividad del trabajo. No existe, en cambio, una relación cuadrática entre estas variables. Limitaciones: La muestra utilizada procede exclusivamente de Cataluña (España), noes perfectamente extrapolable al conjunto de empresas de servicios intensivos enconocimiento y se obtuvo en la fase alcista del ciclo económico. El diseño del estudio estransversal. La clasificación de las empresas como intensivas en conocimiento esdicotómica, en función del sector al que pertenecen. Implicaciones prácticas:Las decisiones sobre la contratación de mano de obra en actividades de servicios de alto valor añadido deberían minimizar las formas de trabajocontingentes, si quieren mejorar su productividad.Implicaciones sociales: Un modelo productivo que pretenda potenciar los servicios de mayor valor añadido no puede descansar sobre la base de un mercado laboral en el que las empresas utilizan una elevada proporción de trabajo contingente en su mano de obra. Valor añadido: Este artículo ofrece nuevos datos para a la escasa literatura que relaciona el uso de trabajo contingente con la productividad en el sector de los servicios intensivos en conocimiento. La creciente importancia de los servicios de alto valor añadido, tanto en empresas de servicios como manufactureras, y el interés por conocer los determinantes de su productividad justifican la necesidad de realizar estudios como el que se presenta.

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The purpose of this study is to investigate the performance persistence of international mutual funds, employing a data sample which includes 2,168 European mutual funds investing in Asia-Pacific region; Japan excluded. Also, a number of performance measures is tested and compared, and especially, this study tries to find out whether iterative Bayesian procedure can be used to provide more accurate predictions on future performance. Finally, this study examines whether the cross-section of mutual fund returns can be explained with simple accounting variables and market risk. To exclude the effect of the Asian currency crisis in 1997, the studied time period includes years from 1999 to 2007. The overall results showed significant performance persistence for repeating winners when performance was tested with contingency tables. Also the annualized alpha spreads between the top and bottom portfolios were more than ten percent at their highest. Nevertheless, the results do not confirm the improved prediction accuracy of the Bayesian alphas.

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The stochastic convergence amongst Mexican Federal entities is analyzed in panel data framework. The joint consideration of cross-section dependence and multiple structural breaks is required to ensure that the statistical inference is based on statistics with good statistical properties. Once these features are accounted for, evidence in favour of stochastic convergence is found. Since stochastic convergence is a necessary, yet insufficient condition for convergence as predicted by economic growth models, the paper also investigates whether-convergence process has taken place. We found that the Mexican states have followed either heterogeneous convergence patterns or divergence process throughout the analyzed period.

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The ecological fallacy (EF) is a common problem regional scientists have to deal with when using aggregated data in their analyses. Although there is a wide number of studies considering different aspects of this problem, little attention has been paid to the potential negative effects of the EF in a time series context. Using Spanish regional unemployment data, this paper shows that EF effects are not only observed at the cross-section level, but also in a time series framework. The empirical evidence obtained shows that analytical regional configurations are the least susceptible to time effects relative to both normative and random regional configurations, while normative configurations are an improvement over random ones.

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A dual model with a nonlinear proton Regge trajectory in the missing mass (M_X^2) channel is constructed. A background based on a direct-channel exotic trajectory, developed and applied earlier for the inclusive electron-proton cross section description in the nucleon resonance region, is used. The parameters of the model are determined from the extrapolations to earlier experiments. Predictions for the low-mass (2 < M_X^2 < 8GeV^2) diffraction dissociation cross sections at the LHC energies are given.

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Dendrochemistry is based on the determination of elements retained in tree rings, which can be useful to characterize environmental occurrences. This work shows elemental mappings obtained by EDXRF of the cross section of a tree stem. The tree is originated from a polluted area in Campinas, São Paulo. Some profiles, as the sulfur one, show variations that can be attributed to external contributions, whereas the silicon one can be inferred to a protection defense natural mechanism. Besides being simultaneous and multielementar, the main advantages here are its performance through a non-destructive sample treatment and the ease of operation of XRF equipments.

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Työn kehityksen kohteena toimii CIRB 500i –robottisolu, jonka sisällä työskentelee korkeaan tuotantokapasiteettiin kehitetty näköjärjestelmällä ohjattu sähköservomanipulaattori. Kokonaisuutena ajatellen työ tekee servotekniikan osalta poikkileikkauksen CIRB 500i –robottisolun matkasta prototyypistä tuotteeksi erilaisine kehitysvaiheineen. Työn alkutaipaleella perehdytään pitkälle pelkkään teoriaan nojautuen mitä on servotekniikka, miten se toimii ja kuinka se viritetään. Tämän jälkeen edellä opitut teoriat konkretisoidaan CIRB 500i –robottisoluun ja siinä käytettävään servotekniikkaan. Robottisolun komponenttien ja laitteistojen tullessa tutuiksi mietitään ja kehitetään kuinka robottisolusta saataisiin entistä kehittyneempi ja käytännöllisempi teknillisestä näkökulmasta katsoen kuitenkaan valmistamisen kustannustehokkuutta unohtamatta. Loppupuolella analysoidaan miten edellä tehdyt kehitystoimenpiteet ovat vaikuttaneet robottisolun toimintaan ja valmistamiseen. Lopuksi sovelletaan teoriaosuuden virityskeinoja servojen virittämiseen käytännössä ja analysoidaan saavutettuja kehittämistyön tuloksia. Lisäksi tehdään katsaus CIRB 500i –robottisolun tulevaisuuden näkymiin.

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Tässä diplomityössä on esitetty työn yhteydessä toteutetun Serpent-ARES-laskentaketjun muodostamiseksi tarvittavat toimenpiteet. ARES-reaktorisydän-simulaattorissa tarvittavien homogenisoitujen ryhmävakiokirjastojen muodostaminen Serpentiä käyttäen tekee laskentaketjusta muiden käytössä olevien reaktorisydämen laskentaketjujen mahdollisista virhelähteistä riippumattoman. Monte Carlo-laskentamenetelmään perustuvaa reaktorifysiikan laskentaohjelmaa käyttämällä ryhmävakiokirjastot muodostetaan uudella menetelmällä ja näin saadaan viranomaiskäyttöön voimayhtiöiden käyttämistä menetelmistä riippumaton laskentaketju reaktorien turvallisuusmarginaalien laskentaan. Työn yhteydessä muodostetun laskentaketjun ja tehtyjen vaikutusalakirjastojen muodostamisrutiinien sekä parametrisovitteiden toimivuus on todettu laskemalla Olkiluoto 3 - reaktorin alkulatauksen säätösauvojen tehokkuuksia ja sammutusmarginaaleja eri olosuhteissa. Menetelmä on todettu toimivaksi parametrien pätevyysalueella ja saadut laskentatulokset ovat oikeaa suuruusluokkaa. Parametrimallin tarkkuutta ja pätevyysaluetta on syytä vielä kehittää, ennen kuin laskentaketjua voidaan käyttää varmentamaan muilla menetelmillä laskettujen tulosten oikeellisuutta.