125 research outputs found

    Ge/SiGe Quantum Well p-i-n Structures for Uncooled Infrared Bolometers

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    Cataloged from PDF version of article.The temperature dependence of current is investigated experimentally for silicon–germanium (Si-Ge) multi-quantum-well p-i-n devices on Si substrates as uncooled bolometer active layers. Temperature coefficient of resistance values as high as −5.8%/K are recorded. This value is considerably higher than that of even commercial bolometer materials in addition to being well above the previous efforts based on CMOS compatible materials

    Measuring CIS Health Systems Using the Stochastic Frontier Analysis (SFA)

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    The Commonwealth of Independent States (CIS) was founded in 1991 after the dissolution of the Union of Soviet Socialist Republics (USSR). The member countries are Azerbaijan, Belarus, Armenia, Kazakhstan, Kyrgyzstan, Moldova, Uzbekistan, Russia, Tajikistan, Turkmenistan and Ukraine. Turkmenistan resigned its full membership status in 2005 and changed its CIS standing to observer member. Drawing on the methods of Least Squares and Maximum Likelihood Estimation of Stochastic Frontier Analysis, we made estimations to find efficiency scores in the health sector by using the data for the period from 2010 to 2015 of the countries that are members of the Commonwealth of Independent States. In the study, we used various factors as dependent and independent variables, including the number of doctors, medical personnel and hospital beds per ten thousand people, the life expectancy at birth, under-five mortality rate and the incidence of tuberculosis per one hundred thousand people. We have found that such factor as the number of doctors effectively influences reduction of the under-five mortality rates and the incidence of tuberculosis, while the factor “the number of hospital beds” is not very effective. Finally, for the CIS countries we made recommendations to popularize the health insurance, to change the old Soviet form of health management in public hospitals, and to implement liberal socio-economic policies. © Yesilyurt O. & Selamzade F. Text. 2020

    On the cosmological mass function theory

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    This paper provides, from one side, a review of the theory of the cosmological mass function from a theoretical point of view, starting from the seminal paper of Press & Shechter (1974) to the last developments (Del Popolo & Gambera (1998, 1999), Sheth & Tormen 1999 (ST), Sheth, Mo & Tormen 2001 (ST1), Jenkins et al. 2001 (J01), Shet & Tormen 2002 (ST2), Del Popolo 2002a, Yagi et al. 2004 (YNY)), and from another side some improvements on the multiplicity function models in literature. ...Comment: Astronomy Reports, in prin

    Ge/SiGe quantum well P-I-N structures for uncooled infrared bolometers

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    The temperature dependence of current is investigated experimentally for silicon-germanium (Si-Ge) multi-quantum-well p-i-n devices on Si substrates as uncooled bolometer active layers. Temperature coefficient of resistance values as high as-5.8%/K are recorded. This value is considerably higher than that of even commercial bolometer materials in addition to being well above the previous efforts based on CMOS compatible materials. © 2006 IEEE

    Experimental and theoretical studies of transport through large scale, partially aligned arrays of single-walled carbon nanotubes in thin film type transistors

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    Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs grown by chemical vapor deposition with systematically varying degrees of alignment and coverage in transistors with a range of channel lengths and orientations perpendicular and parallel to the direction of alignment. A first principles stick-percolation-based transport model provides a simple, yet quantitative framework to interpret the sometimes counterintuitive transport parameters measured in these devices. The results highlight, for example, the dramatic influence of small degrees of SWNT misalignment on transistor performance and imply that coverage and alignment are correlated phenomena and therefore should be simultaneously optimized. The transport characteristics reflect heterogeneity in the underlying anisotropic metal-semiconductor stick-percolating network and cannot be reproduced by classical transport models. © 2007 American Chemical Society

    Impact of Bacillus Calmette-Guérin (BCG) vaccination on postoperative mortality in patients with perioperative SARS-CoV-2 infection

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    There is little evidence around the potentially protective role of previous Bacillus Calmette-Guerin (BCG) vaccination on postoperative mortality in patients with perioperative SARS-CoV-2 vaccination. Prior BCG vaccination did not protect SARS-CoV-2 infected patients against postoperative pulmonary complications and 30-day mortality

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

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    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
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