288 research outputs found

    Self-consistent model for ambipolar tunneling in quantum-well systems

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    We present a self-consistent approach to describe ambipolar tunneling in asymmetrical double quantum wells under steady-state excitation and extend the results to the case of tunneling from a near-surface quantum well to surface states. The results of the model compare very well with the behavior observed in photoluminescence experiments in InGaAs/InPInGaAs/InP asymmetric double quantum wells and in near-surface AlGaAs/GaAsAlGaAs/GaAs single quantum wells.Comment: 10 pages, REVTeX 3.

    291 Cystic fibrosis mortality trend in Italy between 1970 and 2011

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    Long working hours and cardiovascular mortality: a census-based cohort study

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    Objectives Long working hours have been associated with cardiovascular disease (CVD) mortality. However, results are inconsistent and large cohort studies are needed to confirm these findings. Methods We conducted a census-based cohort study including 11,903,540 Italian workers aged 20-64 years, registered in the 2011 census, with a 5-year follow-up (2012-2016). We estimated cause-specific hazard ratios (cHRs) through Cox regression models to quantify the association between long working hours and CVD mortality. Results Over 5 years of follow-up, 17,206 individuals died from CVD (15,262 men and 1944 women). Men working 55 or more hours per week had a cHR of 0.95 (95% confidence interval, CI 0.89-1.02) for all CVDs, while women showed a cHR of 1.19 (95% CI 0.95-1.49). Professional women working more than 55 h per week had a cHR of 1.98 (95% CI 0.87-4.52). Conclusions This study does not support an association between long working hours and CVD mortality among active Italian men, while it suggests a possible excess risk among women, although based on limited number of events

    Sopravvivenza e mortalitĂ  per causa

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    Analisi della mortalitĂ  generale e per causa nelle regioni italian

    We only die once... but from how many causes?

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    Analysing causes of death provides a betterunderstanding of long-term mortality trends. InFrance, the death certificates completed by physiciansgenerally mention several causes of death (2.4 onaverage in 2011). As a general rule, just one of them,the so-called underlying cause, is taken into account.As a result, the contribution of certain diseases-endocrine diseases for example-to mortality isseverely underestimated. In a context of rising lifeexpectancy where people increasingly die not from asingle cause of death but from several, it is importantto also take these contributing causes into account

    Phase-bistable patterns and cavity solitons induced by spatially periodic injection into vertical-cavity surface-emitting lasers

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    Spatial rocking is a kind of resonant forcing able to convert a elf-oscillatory system into a phase-bistable, pattern forming system, whereby the phase of the spatially averaged oscillation field locks to one of two values differing by π. We propose the spatial rocking in an experimentally relevant system the vertical-cavity surface-emitting laser (VCSEL) and demonstrate its feasibility through analytical and numerical tools applied to a VCSEL model. We show phase bistability, spatial patterns, such as roll patterns, domain walls, and phase (dark-ring) solitons, which could be useful for optical information storage and processing purposes
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