180 research outputs found

    Magnetooptic properties of self-trapped excitons in cesium halides

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    A model for the electronic structure of self-trapped excitons in Cs halides is proposed. By applying it, reasonable interpretations were obtained for the magnetic circular polarization (MCP) of the 2 intrinsic emissions in CsI, and for the MCP and EPR in CsBr

    Polarization-stable long-distance interference of independent photons for quantum communications

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    Interference between fully-independent faint laser sources over two 8.5-km full polarization-controlled fiber links was performed, with stable visibility of 47.8%, an essential step towards practical implementation of quantum communication protocols

    Proof-of-principle demonstration of measurement-device-independent quantum key distribution using polarization qubits

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    We perform a proof-of-principle demonstration of the measurement-device-independent quantum key distribution (MDI-QKD) protocol using weak coherent states and polarization-encoded qubits over two optical fiber links of 8.5 km each. Each link was independently stabilized against polarization drifts using a full-polarization control system employing two wavelength-multiplexed control channels. A linear-optics-based polarization Bell-state analyzer was built into the intermediate station, Charlie, which is connected to both Alice and Bob via the optical fiber links. Using decoy-states, a lower bound for the secret-key generation rate of 1.04x10^-6 bits/pulse is computed

    No evidence of response bias in a populationbased childhood cancer survivor questionnaire survey-Results from the Swiss Childhood Cancer Survivor Study

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    Purpose This is the first study to quantify potential nonresponse bias in a childhood cancer survivor questionnaire survey. We describe early and late responders and nonresponders, and estimate nonresponse bias in a nationwide questionnaire survey of survivors. Methods In the Swiss Childhood Cancer Survivor Study, we compared characteristics of early responders (who answered an initial questionnaire), late responders (who answered after ≥1 reminder) and nonresponders. Sociodemographic and cancer-related information was available for the whole population from the Swiss Childhood Cancer Registry. We compared observed prevalence of typical outcomes in responders to the expected prevalence in a complete (100% response) representative population we constructed in order to estimate the effect of nonresponse bias. We constructed the complete population using inverse probability of participation weights. Results Of 2328 survivors, 930 returned the initial questionnaire (40%); 671 returned the questionnaire after ≥1reminder (29%). Compared to early and late responders, we found that the 727 nonresponders (31%) were more likely male, aged <20 years, French or Italian speaking, of foreign nationality, diagnosed with lymphoma or a CNS or germ cell tumor, and treated only with surgery. But observed prevalence of typical estimates (somatic health, medical care, mental health, health behaviors) was similar among the sample of early responders (40%), all responders (69%), and the complete representative population (100%). In this survey, nonresponse bias did not seem to influence observed prevalence estimates. Conclusion Nonresponse bias may play only a minor role in childhood cancer survivor studies, suggesting that results can be generalized to the whole population of such cancer survivors and applied in clinical practice

    Risk factors for overweight and obesity after childhood acute lymphoblastic leukemia in North America and Switzerland: A comparison of two cohort studies.

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    BACKGROUND After childhood acute lymphoblastic leukemia (ALL), sequelae include overweight and obesity, yet with conflicting evidence. We compared the prevalence of overweight and obesity between ≥5-year ALL survivors from the North American Childhood Cancer Survivor Study (CCSS) and the Swiss Childhood Cancer Survivor Study (SCCSS) and described risk factors. METHODS We included adult childhood ALL survivors diagnosed between 1976 and 1999. We matched CCSS participants (3:1) to SCCSS participants by sex and attained age. We calculated body mass index (BMI) from self-reported height and weight for 1287 CCSS and 429 SCCSS participants; we then compared those with siblings (2034) in North America and Switzerland (678) siblings. We assessed risk factors for overweight (BMI 25-29.9 kg/m2 ) and obesity (≥30 kg/m2 ) using multinomial regression. RESULTS We found overweight and obesity significantly more common among survivors in North America when compared with survivors in Switzerland [overweight: 30%, 95% confidence interval (CI): 27-32 vs. 24%, 21-29; obesity: 29%, 27-32 vs. 7%, 5-10] and siblings (overweight: 30%, 27-32 vs. 25%, 22-29; obesity: 24%, 22-26 vs. 6%, 4-8). Survivors in North America [odds ratio (OR) = 1.24, 1.01-1.53] and Switzerland (1.27, 0.74-2.21) were slightly more often obese than siblings. Among survivors, risk factors for obesity included residency in North America (5.8, 3.7-9.0); male (1.7, 1.3-2.3); attained age (≥45 years: 5.1, 2.4-10.8); Non-Hispanic Black (3.4, 1.6-7.0); low household income (2.3, 1.4-3.5); young age at diagnosis (1.6, 1.1-2.2). Cranial radiotherapy ≥18 Gray was only a risk factor for overweight (1.4, 1.0-1.8); steroids were not associated with overweight or obesity. Interaction tests found no evidence of difference in risk factors between cohorts. CONCLUSIONS Although treatment-related risk for overweight and obesity were similar between regions, higher prevalence among survivors in North America identifies important sociodemographic drivers for informing health policy and targeted intervention trials
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