815 research outputs found

    Foliations on modular curves

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    It is proved, that a foliation on a modular curve given by the vertical trajectories of holomorphic differential corresponding to the Hecke eigenform is either the Strebel foliation or the pseudo-Anosov foliation.Comment: to appear Bulletin of the Brazilian Mathematical Society, New Serie

    Biophysical, morphological, canopy optical property, and productivity data from the Superior National Forest

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    Described here are the results of a NASA field experiment conducted in the Superior National Forest near Ely, Minnesota, during the summers of 1983 and 1984. The purpose of the experiment was to examine the use of remote sensing to provide measurements of biophysical parameters in the boreal forests. Leaf area index, biomass, net primary productivity, canopy coverage, overstory and understory species composition data are reported for about 60 sites, representing a range of stand density and age for aspen and spruce. Leaf, needle, and bark high-resolution spectral reflectance and transmittance data are reported for the major boreal forest species. Canopy bidirectional reflectance measurements are provided from a helicopter-mounted Barnes Multiband Modular Radiometer (MMR) and the Thematic Mapper Simulator (TMS) on the NASA C-130 aircraft

    Ten year change in forest succession and composition measured by remote sensing

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    Vegetation dynamics and changes in ecological patterns were measured by remote sensing over a 10 year period (1973 to 1983) for 148,406 landscape elements, covering more than 500 sq km in a protected forested wilderness. Quantitative measurements were made possible by methods to detect ecologically meaningful landscape units; these allowed measurement of ecological transition frequencies and calculation of expected recurrence times. Measured ecological transition frequencies reveal boreal forest wilderness as spatially heterogeneous and highly dynamic, with one-sixth of the area in clearings and early successional stages, consistent with recent postulates about the spatial and temporal patterns of natural ecosystems. Differences between managed forest areas and a protected wilderness allow assessment of different management regimes

    Haemophilus influenzae invasive disease in the United States, 1994-1995: near disappearance of a vaccine-preventable childhood disease.

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    We analyzed national Haemophilus influenzae (Hi) surveillance data from 1994 and 1995 to describe the epidemiology of Hi invasive disease among persons of all ages. Serotype data were available for 376 (56%) of 669 reported Hi cases among children aged 4 years or younger; 184 (49%) were H. influenzae type b (Hib). Among children aged 4 or younger, incidence (per 100,000) of all Hi invasive disease was 1.8 in 1994 and 1.6 (p < 0.05) in 1995. Children aged 5 months or younger had the highest average annual incidence rate of Hib invasive disease (2.2 per 100,000); children aged 6 to 11 months had the next highest rate (1.2 per 100,000)(p < 0.05). Of 181 children with Hib invasive disease whose age in months was known, 85 (47%) were too young (aged 5 months or younger) to have completed a primary series with an Hib-containing vaccine. Of the 83 children with known vaccination status who were eligible to receive a primary series (aged 6 months or older), 52 (63%) were undervaccinated, and the remaining 31 (37%) had completed a primary series in which vaccine failed. Among persons aged 5 years or older with Hi invasive disease, the lowest average annual incidence was among those 20 to 39 years of age (0.15 per 100,000), and the highest was among those aged 80 years or older (2.26 per 100,000). Among persons aged 5 years or older, serotype data were available for 1,372 (71%) of the 1,940 Hi invasive disease cases; 159 (28%) of the 568 Hi cases with known serotype were due to Hib

    Should outbreak response immunization be recommended for measles outbreaks in middle- and low-income countries? An update.

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    Measles caused mortality in >164,000 children in 2008, with most deaths occurring during outbreaks. Nonetheless, the impact and desirability of conducting measles outbreak response immunization (ORI) in middle- and low-income countries has been controversial. World Health Organization guidelines published in 1999 recommended against ORI in such settings, although recently these guidelines have been reversed for countries with measles mortality reduction goals

    Spectral networks

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    We introduce new geometric objects called spectral networks. Spectral networks are networks of trajectories on Riemann surfaces obeying certain local rules. Spectral networks arise naturally in four-dimensional N=2 theories coupled to surface defects, particularly the theories of class S. In these theories spectral networks provide a useful tool for the computation of BPS degeneracies: the network directly determines the degeneracies of solitons living on the surface defect, which in turn determine the degeneracies for particles living in the 4d bulk. Spectral networks also lead to a new map between flat GL(K,C) connections on a two-dimensional surface C and flat abelian connections on an appropriate branched cover Sigma of C. This construction produces natural coordinate systems on moduli spaces of flat GL(K,C) connections on C, which we conjecture are cluster coordinate systems.Comment: 87 pages, 48 figures; v2: typos, correction to general rule for signs of BPS count

    The evaluation of immediate behavioural outcomes of the syndromic case management approach for the treatement of patients with sexually transmitted infections at PHC centres of South Africa: Knowledge, attitudes, beliefs and sexual behaviour

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    This study aimed to determine the immediate behavioural outcomes of the WHO syndromic case management model for STIs in the public health sector in South Africa, on the levels of knowledge, attitudes and beliefs, and behavioural practices (KABPs) concerning STIs. An outcomes evaluation was conducted using KABP methodology. Exit interviews were conducted with 126 STI and non-STI patients at 24 primary health care (PHC) centres in four provinces. Both groups were found to have equally high levels of knowledge about STIs and their attitudes towards and beliefs about STIs were mostly practical and slightly negative, with only promiscuity both stereotyped and stigmatised. However, both groups were found to engage in risky sexual behavioural practices although they also indicated very strong intentions to use condoms in future. Overall, no significant differences were found between the two groups on any of the variables investigated. The implications of these findings for the control and prevention of both classic STIs and HIV/AIDS in South Africa are discussed. Keywords: sexually transmitted infections, syndromic case management, KABP, South Africa, primary health care centres. RÉSUMÉ Le but de cette étude était d'établir les résultats comportementaux immédiats du modèle de l'OMS de la gestion syndromique de cas de maladies sexuellement transmises (STIs) dans le secteur public de santé en Afrique du Sud au niveau de la connaissance, des attitudes, de la croyance et des pratiques (KABP) vis-à-vis les STIs. Une évaluation des résultats a été faite par le biais de la méthodologie KABP. Des entrevues de sortie ont eu lieu auprès de 126 patients de STIs et des patients qui n'en souffrent pas dans 24 centres de santé situés dans quatre provinces. Les résultats ont montré que les deux groupes avaient le même niveau de connaissance des STIs, leur attitude envers les STIs et ce qu'ils croyent des STIs étaient plutôt pratiques et un peu négatifs. La promiscuité était la seule à être stéréotypée et à être stigmatisée. Cependant, tous les deux groupes ont eu des rapports sexuels risqués, même s'ils ont montré une intention d'utiliser des préservatifs dans l'avenir. Dans l'ensemble, il n'y a pas eu de différences importantes entre les deux groupes sur les variables étudiées. Les conséquences de ces résultats pour le contrôle et la prévention des STIs et le VIH/SIDA en Afrique du Sud sont au centre de cette étude. Mots clés : les maladies/infections sexuellement transmises, la gestion syndromique de cas, les centres pour la santé primaire, l'Afrique du Sud. SAHARA J Vol.1(1) 2004: 35-4

    The nonperturbative closed string tachyon vacuum to high level

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    We compute the action of closed bosonic string field theory at quartic order with fields up to level ten. After level four, the value of the potential at the minimum starts oscillating around a nonzero negative value, in contrast with the proposition made in [5]. We try a different truncation scheme in which the value of the potential converges faster with the level. By extrapolating these values, we are able to give a rather precise value for the depth of the potential.Comment: 24 pages. v2: typos corrected, clarified extrapolation in scheme B, and added extrapolated tachyon and dilaton vev's at the end of Section

    Social constructions of gender roles, gender-based violence and HIV/AIDS in two communities of the Western Cape, South Africa

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    The links between gender roles, gender-based violence and HIV/AIDS risk are complex and culturally specific. In this qualitative study we investigated how women and men in two black communities in the Western Cape, South Africa, constructed their gender identities and roles, how they understood gender-based violence, and what they believed about the links between gender relations and HIV risk. First we conducted 16 key informant interviews with members of relevant stakeholder organisations. Then we held eight focus group discussions with community members in single-sex groups. Key findings included the perception that although traditional gender roles were still very much in evidence, shifts in power between men and women were occurring. Also, gender-based violence was regarded as a major problem throughout communities, and was seen to be fuelled by unemployment, poverty and alcohol abuse. HIV/AIDS was regarded as particularly a problem of African communities, with strong themes of stigma, discrimination, and especially ‘othering' evident. Developing effective HIV/AIDS interventions in these communities will require tackling the overlapping as well as divergent constructions of gender, gender violence and HIV which emerged in the study. Keywords: gender roles, gender-based violence, HIV/AIDS, South Africa. RÉSUMÉ Les liens entre les rôles de genre, la violence contre les femmes et le risque du VIH/SIDA sont complexes et culturellement particuliers. Dans cette étude qualitative, nous avons examiné: comment des hommes et des femmes ont construit des identités et les rôles de genre dans deux communautés noires du Cap de l'Ouest, en Afrique du Sud, comment ont-ils compris la violence contre les femmes et ce qu'ils croyaient des liens entre les relations de sexes et le risque du VIH. Dans un premier temps, nous avons mené 16 entretiens principaux d'informateurs auprès des membres des organismes dépositaires. Ensuite, nous avons eu huit discussions des groupes de foyer avec des membres de la communauté en deux groupes différents, un pour les femmes un autre pour les hommes. Les résultats de recherche ont inclus la perception que: même si les rôles de genre traditionnels restent toujours évidents, il y a aussi le déplacement de pouvoir entre les hommes et les femmes. De plus, la violence contre les femmes était vue comme un problème majeur à travers les communautés et d'être aggravée par le chômage, la pauvreté et l'abus d'alcool. Le VIH/SIDA était considéré particulièrement comme un problème des communautés africaines avec des thèmes fortes de stigmatisation, de discrimination et surtout le ‘othering' évidents. Le développement des interventions efficaces du VIH/SIDA dans ces communautés va exiger une maîtrise des constructions de genre qui se recouvrent partiellement et qui sont divergentes également, la violence contre les femmes et le VIH qui ont apparu dans cette étude. Mot clés: les rôles de genre, la violence contre les femmes, le VIH/SIDA, l'Afrique du Sud

    Guiding slow polar molecules with a charged wire

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    We demonstrate experimentally the guiding of cold and slow ND3 molecules along a thin charged wire over a distance of ~0.34 m through an entire molecular beam apparatus. Trajectory simulations confirm that both linear and quadratic high-field-seeking Stark states can be efficiently guided from the beam source up to the detector. A density enhancement up to a factor 7 is reached for decelerated beams with velocities ranging down to ~50 m/s generated by the rotating nozzle technique
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