Gating of high-mobility two-dimensional electron gases in GaAs/AlGaAs heterostructures

We investigate high-mobility two-dimensional electron gases in AlGaAs heterostructures by employing Schottky-gate-dependent measurements of the samples' electron density and mobility. Surprisingly, we find that two different sample configurations can be set in situ with mobilities diering by a factor of more than two in a wide range of densities. This observation is discussed in view of charge redistributions between the doping layers and is relevant for the design of future gateable high-mobility electron gases

Solution structure of Mannobioses unravelled by means of Raman optical activity

Structural analysis of carbohydrates is a complicated endeavour, due to the complexity and diversity of the samples at hand. Herein, we apply a combined computational and experimental approach, employing molecular dynamics (MD) and density functional theory (DFT) calculations together with NMR and Raman optical activity (ROA) measurements, in the structural study of three mannobiose disaccharides, consisting of two mannoses with varying glycosidic linkages. The disaccharide structures make up the scaffold of high mannose glycans and are therefore important targets for structural analysis. Based on the MD population analysis and NMR, the major conformers of each mannobiose were identified and used as input for DFT analysis. By systematically varying the solvent models used to describe water interacting with the molecules and applying overlap integral analysis to the resulting calculational ROA spectra, we found that a full quantum mechanical/molecular mechanical approach is required for an optimal calculation of the ROA parameters. Subsequent normal mode analysis of the predicted vibrational modes was attempted in order to identify possible marker bands for glycosidic linkages. However, the normal mode vibrations of the mannobioses are completely delocalised, presumably due to conformational flexibility in these compounds, rendering the identification of isolated marker bands unfeasible

The Uncharted Passage: Girls\u27 Adolescence in the Developing World

Adolescence is a formative time of transition to adulthood. What happens between the ages of 10 and 19 shapes how girls and boys live out their lives as women and men—not only in the reproductive arena, but in the social and economic realm as well. Yet, despite its impact on human development, adolescence has been sidelined as a research and policy subject in developing countries. While all adolescents deserve our attention, the needs of adolescent girls in the developing world are particularly pressing. This monograph focuses on these girls, presenting statistics to examine the social and economic context of their lives at home, school, and work, and to investigate adolescent reproductive health, marriage, and childbearing. Distinctive features of adolescent girls’ lives include confinement to domestic roles; restricted mobility; inadequate schooling; insufficient opportunities to work for wages; pressure, in many countries, to marry early and to begin childbearing immediately after marriage; and limited control over their reproductive health and fertility. This monograph outlines an agenda for policy, programs, and research, and provides illustrations of successful local efforts to improve the lives of adolescents

Embodying militarism: exploring the spaces and bodies in-between

No description supplie

The epidemiology of NCAA men’s lacrosse injuries, 2009/10-2014/15 academic years

BACKGROUND: Participation in lacrosse has grown at the collegiate levels. However, little research has examined the epidemiology of collegiate men's lacrosse injuries. This study describes the epidemiology of injuries in National Collegiate Athletic Association (NCAA) men's lacrosse during the 2009/10-2014/15 academic years. METHODS: Twenty-five men's lacrosse programs provided 63 team-seasons of data for the NCAA Injury Surveillance Program (NCAA-ISP) during the 2009/10-2014/15 academic years. Injuries occurred from participation in an NCAA-sanctioned practice or competition, and required attention from an AT or physician. Injuries were further classified as time loss (TL) injuries if the injury restricted participation for at least 24 h. Injuries were reported through electronic medical record application used by the team medical staff throughout the academic year. Injury rates per 1000 athlete-exposures (AE), injury rate ratios (RR), 95% confidence intervals (CI), and injury proportions were reported. RESULTS: Overall, 1055 men's lacrosse injuries were reported, leading to an injury rate of 5.29/1000AE; 95%CI: 4.98-5.61. The TL injury rate was 2.74/1000AE (95%CI: 2.51-2.96). The overall injury rate was higher in competition than practice (12.35 vs. 3.90/1000AE; RR = 3.16; 95%CI: 2.79-3.58). Most injuries were to the lower extremity (58.3%), particularly the ankle (14.1%) in competition and the upper leg (14.3%) in practice. Sprains and strains were the most common diagnoses in both competition (26.9 and 23.7%, respectively) and practice (20.2% and 27.4%, respectively). Most injuries in competitions and practices were due to player contact (32.8 and 17.5%, respectively) and non-contact (29.6 and 40.0%, respectively). CONCLUSIONS: Our estimated injury rates are lower than those from previous college men's lacrosse research. This may be due to increased injury awareness, advances in injury prevention exercise programs, or rule changes. Still, injury prevention can aim to continue reducing the incidence and severity of injury, particularly those sustained in competitions and to the lower extremity

Premarital sex and schooling transitions in four sub-Saharan African countries

Using data from the 2004 National Survey of Adolescents conducted in Burkina Faso, Ghana, Malawi, and Uganda, this Population Council working paper investigates the timing of two key transitions in adolescence—school exit and premarital sex—among those who remain enrolled in school at the beginning of adolescence (age 12). Girls appear more vulnerable to dropout once they become sexually mature and once they engage in premarital sex. While girls were found to be less likely than boys, at any given age and controlling for other covariates, to have had premarital sex (except in Ghana), school enrollment and the timing of school entry were not consistent factors explaining gender differences. Results indicate that the negative consequences for schooling associated with sexual maturation and premarital sex appear to be greater for adolescents in these four countries, especially for girls, than the consequences of leaving school early for the likelihood of premarital sex. Future studies that collect more-detailed information on the educational environment should help clarify the associations between school experiences and sexual behavior among young people in sub-Saharan Africa

Injury Rates in Age-Only Versus Age-and-Weight Playing Standard Conditions in American Youth Football

BACKGROUND: American youth football leagues are typically structured using either age-only (AO) or age-and-weight (AW) playing standard conditions. These playing standard conditions group players by age in the former condition and by a combination of age and weight in the latter condition. However, no study has systematically compared injury risk between these 2 playing standards. PURPOSE: To compare injury rates between youth tackle football players in the AO and AW playing standard conditions. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Athletic trainers evaluated and recorded injuries at each practice and game during the 2012 and 2013 football seasons. Players (age, 5-14 years) were drawn from 13 recreational leagues across 6 states. The sample included 4092 athlete-seasons (AW, 2065; AO, 2027) from 210 teams (AW, 106; O, 104). Injury rate ratios (RRs) with 95% CIs were used to compare the playing standard conditions. Multivariate Poisson regression was used to estimate RRs adjusted for residual effects of age and clustering by team and league. There were 4 endpoints of interest: (1) any injury, (2) non-time loss (NTL) injuries only, (3) time loss (TL) injuries only, and (4) concussions only. RESULTS: Over 2 seasons, the cohort accumulated 1475 injuries and 142,536 athlete-exposures (AEs). The most common injuries were contusions (34.4%), ligament sprains (16.3%), concussions (9.6%), and muscle strains (7.8%). The overall injury rate for both playing standard conditions combined was 10.3 per 1000 AEs (95% CI, 9.8-10.9). The TL injury, NTL injury, and concussion rates in both playing standard conditions combined were 3.1, 7.2, and 1.0 per 1000 AEs, respectively. In multivariate Poisson regression models controlling for age, team, and league, no differences were found between playing standard conditions in the overall injury rate (RRoverall, 1.1; 95% CI, 0.4-2.6). Rates for the other 3 endpoints were also similar (RRNTL, 1.1 [95% CI, 0.4-3.0]; RRTL, 0.9 [95% CI, 0.4-1.9]; RRconcussion, 0.6 [95% CI, 0.3-1.4]). CONCLUSION: For the injury endpoints examined in this study, the injury rates were similar in the AO and AW playing standards. Future research should examine other policies, rules, and behavioral factors that may affect injury risk within youth football

How acceptable are antiretrovirals for the prevention of sexually transmitted HIV? A review of research on the acceptability of oral pre-exposure prophylaxis and treatment as prevention

Recent research has demonstrated how antiretrovirals (ARVs) could be effective in the prevention of sexually transmitted HIV. We review research on the acceptability of oral pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) for HIV prevention amongst potential users. We consider with whom, where and in what context this research has been conducted, how acceptability has been approached, and what research gaps remain. Findings from 33 studies show a lack of TasP research, PrEP studies which have focused largely on men who have sex with men (MSM) in a US context, and varied measures of acceptability. In order to identify when, where and for whom PrEP and TasP would be most appropriate and effective, research is needed in five areas: acceptability of TasP to people living with HIV; motivation for PrEP use and adherence; current perceptions and management of risk; the impact of broader social and structural factors; and consistent definition and operationalisation of acceptability which moves beyond adherence

Delineamentos para uma teoria da Museologia

The guiding principles in the formulation of a Museology theory were established\ud and disseminated internationally from the mid-1980s, and are related to the creation of the\ud International Committee for Museology (Icofom), associated with the International Council of\ud Museums (Icom). The opinions regarding the nature of so-called museological knowledge\ud were issued under the very specific conditions of each groups composition and of the intellectual\ud work undertook in the occasion. Despite the difficulties with the wording, risen in tandem with\ud the exercise (the terminology problem), we focused on the conjuncture that surrounded the\ud formulation: the environment, the aims, the way in which it was composed and the foundations\ud that characterise it, as well as some of the discussions that took place, which revealed aspects\ud that have been handed down as a legacy in this field of specialization