54 research outputs found

    Magnetron Sputter deposition of a 48-member cuprate superconductor library: Bi2Sr2YxCa1-xCu2Oy (0.5 <= x <= 1) linearly varying in steps of 0.01

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    Using magnetron sputtering, a spatial composition spread approach was applied successfully to obtain 48-member libraries of the Bi2Sr2YxCa1-xCu2Oy (0.5<= x <=1)cuprate superconducting system. The libraries of each system were deposited onto (100) single crystal MgO, mounted on a water cooled rotating table, using two targets: the antiferromagnetic insulator Bi2Sr2YCu2Oy (P=98 W RF) and the hole doped superconductor Bi2Sr2CaCu2Oy (P=44 W DC). A low chamber pressure of 0.81 mTorr argon is used to reduce scattering by the process gas. To minimize oxygen resputtering a substrate bias of -20 V was used as well as a process gas free of oxygen. A rapid thermal processor is used to post-anneal the amorphous deposited films. A step annealing regime was used, with a ramp rate of 5 degrees C/s for heating and cooling, with a first plateau at 780 C held for 200 s, and a second at 875 C held for 480 s. X-ray diffraction reveals that the films develop crystalline order with the c-axis lattice parameter contracting linearly from 30.55 Angstroms (x=0.5) to 30.24 Angstroms (x=1.0) with increasing Y-content, consistent with bulk values. The crystallized films are polycrystalline, developing preferred orientation (c-axis parallel to the substrate) for thinner members of the library. There is a change of 0.01 in doping per library member which will enable further studies to densely map phase space.Comment: 4 pages, 6 figures, submitted Jan. 31, 2007: Applied Surface Science - Proceedings of the 4th International Workshop on Combinatorial Materials Science & Technology, San Juan, Puerto Ric

    Projection of populations by level of educational attainment, age, and sex for 120 countries for 2005-2050

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    Using demographic multi-state, cohort-component methods, we produce projections for 120 countries (covering 93% of the world population in 2005) by five-year age groups, sex, and four levels of educational attainment for the years 2005-2050. Taking into account differentials in fertility and mortality by education level, we present the first systematic global educational attainment projections according to four widely differing education scenarios. The results show the possible range of future educational attainment trends around the world, thereby contributing to long-term economic and social planning at the national and international levels, and to the assessment of the feasibility of international education goals

    Stoichiometry control of magnetron sputtered Bi2_2Sr2_2Ca1x_{1-x}Yx_xCu2_2Oy_y (0\lex\le0.5) thin film, composition spread libraries: Substrate bias and gas density factors

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    A magnetron sputtering method for the production of thin-film libraries with a spatially varying composition, x, in Bi2Sr2Ca1-xYxCu2Oy (0<=x<=0.5) has been developed. Two targets with a composition of Bi2Sr2YCu2O_{8.5 + \delta} and Bi_2Sr_2CaCu_2O_{8 + \delta} are co-sputtered with appropriate masks. The target masks produce a linear variation in opposite, but co-linear radial direction, and the rotation speed of the substrate table is sufficient to intimately mix the atoms. EDS/WDS composition studies of the films show a depletion of Sr and Bi that is due to oxygen anion resputtering. The depletion is most pronounced at the centre of the film (i.e. on-axis with the target) and falls off symmetrically to either side of the 75 mm substrate. At either edge of the film the stoichiometry matches the desired ratios. Using a 12 mTorr process gas of argon and oxygen in a 2:1 ratio, the strontium depletion is corrected. The bismuth depletion is eliminated by employing a rotating carbon brush apparatus which supplies a -20 V DC bias to the sample substrate. The negative substrate bias has been used successfully with an increased chamber pressure to eliminate the resputtering effect across the film. The result is a thin film composition spread library with the desired stoichiometry.Comment: 16 pages, 12 figures, 4 tables, submitted to Physica C - Superconductivity (April 15, 2005), elsart.st

    Reconstruction of populations by age, sex and level of educational attainment for 120 countries for 1970-2000

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    Using demographic multi-state methods for back projecting the populations of 120 countries by age, sex and level of educational attainment from 2000 to 1970 (covering 93 percent of the 2000 world population), this paper presents an ambitious effort to reconstruct human capital data which are essential for empirically studying the aggregate level returns to education. Unlike earlier reconstruction efforts, this new dataset jointly produced at the International Institute for Applied Systems Analysis (IIASA) and the Vienna Institute of Demography (VID) gives the full educational attainment distributions for four categories (no education, primary, secondary and tertiary education) by five-year age groups and with definitions that are strictly comparable across time. Based on empirical distributions of educational attainment by age and sex for the year 2000, the method moves backward along cohort lines while explicitly considering the fact that men and women with different education have different levels of mortality. The resulting dataset will allow new estimates on the impact of age-specific human capital growth on economic growth and first results unlike earlier a consistently positive effect

    Lost in space? The role of place in the delivery of social welfare law advice over the telephone and face-to-face

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    Advice that is provided exclusively over the telephone has been promoted by government as more convenient and accessible than face-to-face appointments. The resulting push towards telephone-only provision, as implemented by the Legal Aid, Sentencing and Punishment of Offenders Act 2012, challenges the long history of association between social welfare law advice and local delivery within disadvantaged communities. This article reports on qualitative research comparing telephone and face-to-face advice which uncovers the continuing relevance of place in the dynamics and mechanics of social welfare law provision. Familiarity with the geographical location, knowledge of local policies and procedures, relationships with opponents and allies, and an understanding of the ‘local legal culture’ mean that face-to-face advisers are often able to conduct their legal casework more effectively. Conversely, local knowledge is unlikely to be available to Community Legal Advice telephone advisers. This research suggests that, in addition, telephone-only advisers may be developing a more narrow understanding of the essential qualities of casework. These findings are particularly significant in view of the likely future expansion of remote methods of delivery in legal aid work

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    Demographic and human-capital trends in Eastern Europe and Sub-Saharan Africa

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    In the next two decades, the world will face two major - and opposing - demographic challenges: rapid population growth and rapid population aging. In an increasingly economically interdependent world, policymakers will simultaneously face a strain on resources caused by population growth and a shortage of labor spurred by the graying of the population. This paper, based on new data created by the authors, will help inform decision making by forecasting population trends in Eastern Europe and sub-Saharan Africa, regions that epitomize this demographic phenomenon's two disparate poles. While sub-Saharan Africa will grow faster than any other part of the world in the next century, resulting in a population explosion that will boost the workforce, Eastern Europe will shrink the most quickly. The silver lining in Europe's graying workforce may be that population decline could be compensated to some degree by increases in human capital. One of population growth's most important ramifications is its inverse correlation with educational attainment. While the Eastern European population is expected to decline steadily, educational attainment among its working-age population will increase at the same time, which is likely to lead to higher per capita productivity. Education is a key part of the picture in Africa, too. While high population growth will expand the labor force, it will not boost economic growth unless education is expanded commensurately. A scenario of rapid population increases without parallel growth in education would precipitate a serious humanitarian and development crisis in sub-Saharan Africa. Human-capital trends and demographic trends must be taken into account when we speculate on future migration patterns to and from these regions
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