Intensity dependences of the nonlinear optical excitation of plasmons in graphene

Recently, we demonstrated an all-optical coupling scheme for plasmons, which takes advantage of the intrinsic nonlinear optical response of graphene. Frequency mixing using free-space, visible light pulses generates surface plasmons in a planar graphene sample, where the phase matching condition can define both the wavevector and energy of surface waves and intraband transitions. Here, we also show that the plasmon generation process is strongly intensity-dependent, with resonance features washed out for absorbed pulse fluences greater than 0.1 J m−2. This implies a subtle interplay between the nonlinear generation process and sample heating. We discuss these effects in terms of a non-equilibrium charge distribution using a two-temperature model.Peer ReviewedPostprint (author's final draft

Self- induction of abortion among women accessing second- trimester abortion services in the public sector, Western Cape Province, South Africa : An exploratory study

KMBackground: Despite South Africa's liberal abortion law permitting abortion on request in the first trimester and under restricted conditions for second-trimester pregnancies, the practice of unsafe self-induced abortion persists. However, the prevalence of this practice, the methods used and the reasons behind it are relatively under-researched. As part of a larger study seeking to improve abortion services in the Western Cape Province, we explored reports of prior attempts to self-induce abortion among women undergoing legal second-trimester abortion. Objectives: To describe the prevalence and methods of and factors related to unsuccessful attempts at self-induction of abortion by women presenting without complications and seeking second-trimester abortion at public health facilities in the Western Cape. Methods: In a cross-sectional study from April to August 2010, 194 consenting women undergoing second-trimester abortion were interviewed by trained fieldworkers using structured questionnaires at four public sector facilities near Cape Town. Results: Thirty-four women (17.5%; 95% confidence interval 12.7 - 23.4) reported an unsuccessful attempt to self-induce abortion during the current pregnancy before going to a facility for second-trimester abortion. No factors were significantly associated with self-induction, but a relatively high proportion of this small sample were unemployed and spoke an indigenous African language at home. A readily available herbal product called Stametta was most commonly used; other methods included taking tablets bought from unlicensed providers and using other herbal remedies. No use of physical methods was reported. Conclusions: The prevalence of unsafe self-induction of abortion is relatively high in the Western Cape. Efforts to inform women in the community about the availability of free services in the public sector and to educate them about the dangers of self-induction and unsafe providers should be strengthened to help address this public health issue

Water and beverage consumption among children age 4-13y in the United States: analyses of 2005–2010 NHANES data

BACKGROUND: Few studies have examined water consumption patterns among US children. Additionally, recent data on total water consumption as it relates to the Dietary Reference Intakes (DRI) are lacking. This study evaluated the consumption of plain water (tap and bottled) and other beverages among US children by age group, gender, income-to-poverty ratio, and race/ethnicity. Comparisons were made to DRI values for water consumption from all sources. METHODS: Data from two non-consecutive 24-hour recalls from 3 cycles of NHANES (2005–2006, 2007–2008 and 2009–2010) were used to assess water and beverage consumption among 4,766 children age 4-13y. Beverages were classified into 9 groups: water (tap and bottled), plain and flavored milk, 100% fruit juice, soda/soft drinks (regular and diet), fruit drinks, sports drinks, coffee, tea, and energy drinks. Total water intakes from plain water, beverages, and food were compared to DRIs for the US. Total water volume per 1,000 kcal was also examined. RESULTS: Water and other beverages contributed 70-75% of dietary water, with 25-30% provided by moisture in foods, depending on age. Plain water, tap and bottled, contributed 25-30% of total dietary water. In general, tap water represented 60% of drinking water volume whereas bottled water represented 40%. Non-Hispanic white children consumed the most tap water, whereas Mexican-American children consumed the most bottled water. Plain water consumption (bottled and tap) tended to be associated with higher incomes. No group of US children came close to satisfying the DRIs for water. At least 75% of children 4-8y, 87% of girls 9-13y, and 85% of boys 9-13y did not meet DRIs for total water intake. Water volume per 1,000 kcal, another criterion of adequate hydration, was 0.85-0.95 L/1,000 kcal, short of the desirable levels of 1.0-1.5 L/1,000 kcal. CONCLUSIONS: Water intakes at below-recommended levels may be a cause for concern. Data on water and beverage intake for the population and by socio-demographic group provides useful information to target interventions for increasing water intake among children

Variabilité Intra-saisonnière De La Grande Saison Pluvieuse Dans Le Sud-Benin

L’Afrique de l’Ouest sub-saharienne est une des régions du monde qui a connu la plus forte fluctuation des précipitations intra- saisonnières au cours de la seconde moitié du 20ème siècle. La présente étude vise à mieux connaître les indicateurs de la variabilité intra-saisonnière de la grande saison pluvieuse dans le sud-Benin. Les données utilisées dans le cadre de cette étude concernent les hauteurs décadaires mensuelles et annuelles de pluie dans les stations situées dans le sud-Bénin. Les dates de début, de fin, les longueurs et cumuls décadaires, mensuels, saisonniers et les séquences sèches maximales ainsi que les cumuls annuels de la grande saison des pluie a été déterminé à partir du logiciel des traitement des données Instat+. L’indice pluviométrique de Lamb, a été utilisé pour analyser la variabilité interannuelle de la grande saison pluvieuse. Il en résulte qu’en moyenne, la grande saison pluvieuse démarre au cours de la troisième décade de mars et finit en moyenne entre le 16 juillet (jour 198) et le 2 août (jour 215) sur l’ensemble des stations. La longueur moyenne de la grande saison des pluies varie entre 106 et 130 jours sur l’ensemble des stations. La moyenne du Nombre de Jours de Pluie (NJP) varie entre 28 et 44 jours. De même, le cumul pluviométrique annuel a connu une baisse de 100 à 300 mm sur l’ensemble des stations. Le nombre de jours pluvieux pendant la grande saison a baissé de 10 jours en moyenne. La grande saison des pluies démarre tardivement et finit plus tôt. 3 Sub-Saharan West Africa is one of the regions in the world that experienced the greatest seasonal fluctuation of precipitation during the second half of the 20th century. This study aims to better understand the indicators of intra-seasonal variability of the great rainy season in southern Benin. The quantitative and qualitative data used in this study concern the monthly and annual rainfall heights in stations in southern Benin as well as the qualitative data and information obtained in the field. The dates of start, end, decadal, monthly, seasonal and maximum dry periods and accumulations as well as the annual totals for the major rainy season were determined from the Instat + data processing software. Lamb's rainfall index was used to analyze the interannual variability of the major rainy season. As a result, on average, the great rainy season starts during the third dekad ofMarch and ends on average between July 16th (day 198) and August 2nd (day 215) on all the stations. The average length of the long rainy season varies between 106 and 130 days on all stations. The average Number of Days of Rain (NDR) varies between 28 and 44 days. Similarly, the cumulative annual rainfall fell by 100 to 300 mm on all stations. The number of rainy days during the high season fell by 10 days on average. The big rainy season starts late and finishes earlier

La dimension migratoire des Antilles

Forcée, dirigée, volontaire... la migration a toujours été au coeur des processus adaptatifs qui ont forgé l'actuelle société antillaise, soumise à rude épreuve au cours des dernières décennies : mutation statutaire, explosion démographique et exutoire migratoire massif, révolution des transports aériens et émergence d'une société "bipolaire", passage de l'économie de plantation à l'économie de transferts...Ainsi la migration, vecteur de tous ces changements et moyen d'ajustement entre espaces économiques hiérarchisés, s'articule avec de nouvelles normes de mobilité que la seule observation des phénomènes démographiques et des mouvements de population ne suffit plus à appréhender. Par son approche multidisciplinaire, cet ouvrage constitue un essai scientifique de "migratologie", qui appréhende la dimension migratoire des Antilles comme un fait de société, au travers des processus résultant des facteurs spatio-temporels caraïbéens (première partie), des déterminants institutionnels et économiques (deuxième partie), et de la dynamique des courants migratoires (troisième partie). (Résumé d'auteur

How women’s empowerment influences fertility-related outcomes and contraceptive practices: A cross-sectional study in Mozambique

Women’s empowerment could be a crucial step for tackling gender inequality and improve women’s reproductive health and rights in Mozambique. This study aims to examine how different domains of women’s empowerment influence fertility-related outcomes and contraceptive practices in Mozambique. We used the 2015 Demographic Health Survey (DHS) conducted in Mozambique from which a sample of 2072 women aged 15 to 49 years were selected and included in this analysis. A principal component analysis was performed, and the components retained were identified as the domains of empowerment. These were: Beliefs about violence against women, Decision-making, and Control over sexuality and safe sex. A multinomial logistic regression was run to estimate the association between levels of empowerment for each domain and the study outcomes. Crude and adjusted odds ratio (OR) were calculated, with 95% confidence intervals (95% CI). Beliefs about violence against women and Control over sexuality and safe sex were positively associated with having 1 to 4 children. Control over sexuality and safe sex also increased likelihood of women wanting to space childbearing over more than 2 years. Decision-making increased the odds of women not wanting more children. Middle to high empowerment levels for Control over sexuality and safe sex also increased the chances of using any type of contraceptive method and using it for longer periods. All domains, from the middle to high levels of empowerment, decreased the chances of women not wanting to use contraception. Our study confirmed the multidimensional nature of empowerment showing that each domain had a different effect over specific fertility and contraceptive outcomes and reinforced the importance of a domain approach for estimating and understanding empowerment. It also revealed the critical role of Control over sexuality and safe sex domain for improving women’s ability to decide over fertility and contraceptive practices in Mozambique.We gratefully acknowledge the PhD grant from Fundação para a Ciência e a Tecnologia to SCL (SFRH/BD/146625/2019) and the contract to SF (CEECIND/01516/2017). We also thank the Faculty Research Committee (FRC) of the Faculty of Health Sciences of the University of Cape Town for the Post Graduate Research Training Grant (FRC Award 2019) to SCL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

One-to-One Laptop Project: Perceptions of Teachers, Parents, and Students

One-to-one laptop programs are becoming more prevalent across the world in K-12 institutions. School districts are searching for more engaging tools that seek to have impact on school success, such as grade achievement, college/career preparation, and/or 21st-century skill preparation and attainment. Additionally, boards of education continuously want some positive indication of the return on their substantial financial investment. This study utilized surveys of three important stakeholder groups (parents, students, and teachers) related to a one-to-one laptop project in a moderately-sized rural Midwestern school district. Perceptions about how often laptops were used in the classroom setting and across content areas (Language Arts, Social Studies, Mathematics, and Science) were explored. Finally, the same respondents were asked to identify their perceptions about how laptop computers had a positive or negative impact on quarterly grade averages within these same content areas. Results were extrapolated and associated with the Rogers‟ Innovation Continuum (Innovator, Early Adopter, Early Majority, Late Majority). Data indicated significant mean differences in perceptions among the three groups in terms of use. Teachers believed students were using laptops more often than students or parents reported their use. Nearly all groups reported Mathematics as the area with lowest amount of use and Science as the area with the highest. Almost all three groups believed laptops had little to no effect on quarterly grade averages. Mathematics teachers, however, believed laptops had a decidedly negative effect. The data seemed to indicate a need for additional teacher training on best practices for implementing laptops within the content areas, as well as specific attention paid to mathematics instructors. Further, the school district was mapped to an Early Adopter on the Rogers‟ scale. This indicates a need for further implementation and refinement if it is to be an accepted part of the educational culture