142 research outputs found
Limit theorems for Lévy flights on a 1D Lévy random medium
We study a random walk on a point process given by an ordered array of points (ωk, k ∈ Z) on the real line. The distances ωk+1 − ωk are i.i.d. random variables in the domain of attraction of a β-stable law, with β ∈ (0, 1) ∪ (1, 2). The random walk has i.i.d. jumps such that the transition probabilities between ωk and ωℓ depend on ℓ − k and are given by the distribution of a Z-valued random variable in the domain of attraction of an α-stable law, with α ∈ (0, 1) ∪ (1, 2). Since the defining variables, for both the random walk and the point process, are heavy-tailed, we speak of a Lévy flight on a Lévy random medium. For all combinations of the parameters α and β, we prove the annealed functional limit theorem for the suitably rescaled process, relative to the optimal Skorokhod topology in each case. When the limit process is not càdlàg, we prove convergence of the finite-dimensional distributions. When the limit process is deterministic, we also prove a limit theorem for the fluctuations, again relative to the optimal Skorokhod topology
Risk adjustment for inter-hospital comparison of caesarean delivery rates in low-risk deliveries
BACKGROUND: Caesarean delivery (CD) rates have been frequently used as quality measures for maternity service comparisons. More recently, primary CD rates (CD in women without previous CD) or CD rates within selected categories such as nulliparous, term, cephalic singleton deliveries (NTCS) have been used. The objective of this study is to determine the extent to which risk adjustment for clinical and socio-demographic variables is needed for inter-hospital comparisons of CD rates in women without previous CD and in NTCS deliveries. METHODS: Hospital discharge records of women who delivered in Emilia-Romagna Region (Italy) from January, 2007 to June 2009 and in Tuscany Region for year 2009 were linked with birth certificates. Adjusted RRs of CD in women without a previous Caesarean and NTCS were estimated using Poisson regression. Percentage differences in RR before and after adjustment were calculated and hospital rankings, based on crude and adjusted RRs, were examined. RESULTS: Adjusted RR differed substantially from crude RR in women without a previous Caesarean and only marginally in NTCS group. Hospital ranking was markedly affected by adjustment in women without a previous CD, but less in NTCS. CONCLUSION: Risk adjustment is warranted for inter-hospital comparisons of primary CD rates but not for NTCS CD rates. Crude NTCS CD rates are a reliable estimate of adjusted NTCS CD
Desenvolvimento de uma Bancada Experimental para Inspeção Automatizada de Produtos Industriais por Visão Computacional
O desenvolvimento de um sistema de inspeção automatizada baseado em imagens pode apresentar desafios não só relacionados com as técnicas de processamento empregadas, mas também com as condições de operação. Artefatos resultantes da movimentação dos produtos inspecionados durante a aquisição de imagens devem ser considerados. No presente trabalho é apresentado o desenvolvimento de uma bancada que permite caracterizar de forma mais adequada o cenário real de utilização destes sistemas e, desta forma, simplificar o desenvolvimento e validação deste tipo de ferramenta. Os resultados experimentais obtidos demonstram a reprodução de efeitos de imagens obtidos em linhas reais de produção e, desta forma, comprovam a efetividade da utilização da bancada proposta
Migrant pathways to community mental health centres in Italy.
Background: Many studies indicate that migrants in western countries have limited access to and low utilization of community mental health centres (CMHCs) despite the high prevalence of mental disorders. Aims: We aimed to compare migrant pathways to care across four CMHCs located in different Italian provinces and to identify pathway to care predictors. Methods: Migrants attending the four CMHCs between 1 July 1999 and 31 December 2007 were included in the study. Data were gathered retrospectively from clinical data sets and chart review. Results: Five hundred and eleven (511) migrants attended the four CMHCs, 61% were referred by GPs or other health services and 39% followed non-medical pathways to care (self-referral or through social and voluntary organizations), with important site variations. Younger age and being married were predictors of medical pathways to care; lacking a residence permit and having a diagnosis of substance abuse were related to non-medical pathways. Conclusions: Pathways to CMHCs are complex and influenced by many factors. Non-medical pathways to care seem to be frequent among migrants in Italy. More attention should be paid to developing psychiatric consultation liaison models that also encompass the social services and voluntary organizations
Migrant pathways to community mental health centres in Italy.
Background: Many studies indicate that migrants in western countries have limited access to and low utilization of community mental health centres (CMHCs) despite the high prevalence of mental disorders. Aims: We aimed to compare migrant pathways to care across four CMHCs located in different Italian provinces and to identify pathway to care predictors. Methods: Migrants attending the four CMHCs between 1 July 1999 and 31 December 2007 were included in the study. Data were gathered retrospectively from clinical data sets and chart review. Results: Five hundred and eleven (511) migrants attended the four CMHCs, 61% were referred by GPs or other health services and 39% followed non-medical pathways to care (self-referral or through social and voluntary organizations), with important site variations. Younger age and being married were predictors of medical pathways to care; lacking a residence permit and having a diagnosis of substance abuse were related to non-medical pathways. Conclusions: Pathways to CMHCs are complex and influenced by many factors. Non-medical pathways to care seem to be frequent among migrants in Italy. More attention should be paid to developing psychiatric consultation liaison models that also encompass the social services and voluntary organizations
new evidence for thermal boundary resistance effects in superconducting 6 ghz cavities
Thermal boundary resistance and, more specifically, Kapitza resistance effects have been often considered as a possible source of "non ideal" superconducting accelerating cavity behavior, through the formation of a temperature difference between the inner cavity superconducting surface and the helium bath. However, in the present literature the general reported assessment is that such effects could be neglected, at least at low or moderate input power. In this communication we present new data on small test bulk Nb 6Ghz cavities, showing that when the cavity surface resistance (or the Q) is plotted as a function of the temperature at constant input power, a clear anomaly occurs at the Helium superfluid transition point Tλ reflecting the abrupt change of the thermal boundary resistance at that temperature. The data analysis shows that this anomaly is consistent with the typically measured values of the thermal boundary (Kapitza) resistance. Implications on the cavity optimization strategy are finally discussed
Generación de energía solar fotovoltaica en grandes superficies cubiertas de la ciudad de Paraná, Entre Ríos
El objetivo de este trabajo fue determinar la generación de energía eléctrica a través de plantas solares fotovoltaicas diseñadas sobre superficies cubiertas del parque industrial de la ciudad de Paraná. A partir de un relevamiento y selección de industrias con superficie cubierta mayor a 500 m² se identifican diferentes escenarios según la forma, inclinación y orientación de las cubiertas. A través del modelado de los escenarios con el software PVSyst se obtuvieron resultados de la productividad final (YF) e influencia de la radiación sobre cada situación. Sobre un total de 113.142 m² se obtiene una generación de 22.014 MWh al año, con pérdidas del 10,7% en comparación con un diseño óptimo. Se concluye que en el área de estudio se debe comenzar a diseñar edificios con orientación y geometría óptima para incorporar sistemas fotovoltaicos y maximizar la producción de energía limpia y reducir el impacto ambiental.The objective of this work was focused to determine the generation of electric energy through photovoltaic solar plants, which were assumed to be installed on covered surfaces of the industrial park of Paraná city. From a survey and selection of industries with a surface area of more than 500 m², different scenarios were identified according to the shape, inclination and orientation of the decks. Through modeling of these scenarios with the PVSyst software the results of the final yield (YF) and the influence of the radiation on each situation were obtained. Of a total of 113,142 m², a generation of 22,014 MWh per year was obtained, with losses of 10.7% compared to an optimum design. It is concluded that in the study area, the design of buildings with optimum orientation and geometry to incorporate photovoltaic systems should be started in order to maximize the production of clean energy and reduce the environmental impact.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
Generación de energía solar fotovoltaica en grandes superficies cubiertas de la ciudad de Paraná, Entre Ríos
El objetivo de este trabajo fue determinar la generación de energía eléctrica a través de plantas solares fotovoltaicas diseñadas sobre superficies cubiertas del parque industrial de la ciudad de Paraná. A partir de un relevamiento y selección de industrias con superficie cubierta mayor a 500 m² se identifican diferentes escenarios según la forma, inclinación y orientación de las cubiertas. A través del modelado de los escenarios con el software PVSyst se obtuvieron resultados de la productividad final (YF) e influencia de la radiación sobre cada situación. Sobre un total de 113.142 m² se obtiene una generación de 22.014 MWh al año, con pérdidas del 10,7% en comparación con un diseño óptimo. Se concluye que en el área de estudio se debe comenzar a diseñar edificios con orientación y geometría óptima para incorporar sistemas fotovoltaicos y maximizar la producción de energía limpia y reducir el impacto ambiental.The objective of this work was focused to determine the generation of electric energy through photovoltaic solar plants, which were assumed to be installed on covered surfaces of the industrial park of Paraná city. From a survey and selection of industries with a surface area of more than 500 m², different scenarios were identified according to the shape, inclination and orientation of the decks. Through modeling of these scenarios with the PVSyst software the results of the final yield (YF) and the influence of the radiation on each situation were obtained. Of a total of 113,142 m², a generation of 22,014 MWh per year was obtained, with losses of 10.7% compared to an optimum design. It is concluded that in the study area, the design of buildings with optimum orientation and geometry to incorporate photovoltaic systems should be started in order to maximize the production of clean energy and reduce the environmental impact.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
Validation of techniques to mitigate copper surface contamination in CUORE
In this article we describe the background challenges for the CUORE
experiment posed by surface contamination of inert detector materials such as
copper, and present three techniques explored to mitigate these backgrounds.
Using data from a dedicated test apparatus constructed to validate and compare
these techniques we demonstrate that copper surface contamination levels better
than 10E-07 - 10E-08 Bq/cm2 are achieved for 238U and 232Th. If these levels
are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit
on the number of background counts in the region of interest is 0.02-0.03
counts/keV/kg/y depending on the adopted mitigation technique.Comment: 10 pages, 6 figures, 6 table
The low energy spectrum of TeO2 bolometers: results and dark matter perspectives for the CUORE-0 and CUORE experiments
We collected 19.4 days of data from four 750 g TeO2 bolometers, and in three
of them we were able to set the energy threshold around 3 keV using a new
analysis technique. We found a background rate ranging from 25 cpd/keV/kg at 3
keV to 2 cpd/keV/kg at 25 keV, and a peak at 4.7 keV. The origin of this peak
is presently unknown, but its presence is confirmed by a reanalysis of 62.7
kg.days of data from the finished CUORICINO experiment. Finally, we report the
expected sensitivities of the CUORE0 (52 bolometers) and CUORE (988 bolometers)
experiments to a WIMP annual modulation signal.Comment: 9 pages, 10 figure
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