6,340 research outputs found

    Building the Brazilian Academic Genealogy Tree

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    Along the history, many researchers provided remarkable contributions to science, not only advancing knowledge but also in terms of mentoring new scientists. Currently, identifying and studying the formation of researchers over the years is a challenging task as current repositories of theses and dissertations are cataloged in a decentralized way through many local digital libraries. Following our previous work in which we created and analyzed a large collection of genealogy trees extracted from NDLTD, in this paper we focus our attention on building such trees for the Brazilian research community. For this, we use data from the Lattes Platform, an internationally renowned initiative from CNPq, the Brazilian National Council for Scientific and Technological Development, for managing information about individual researchers and research groups in Brazil

    Dietary patterns and nutrient intakes of a South African population and asymptomatic people infected with Human Immunodeficiency Virus: The transition health and urbanisation in South Africa (Thusa) study

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    There is increased emphasis on the quality of food and the overall pattern of micronutrient intake as an integral consideration for food security particularly among people living with HIV/AIDS (PLWHA). However, limited data exist on food consumption and nutrient intakes for populations in sub-Saharan Africa. The study examined dietary patterns and their relationship with nutrient intakes in HIV uninfected (HIV-) and infected (HIV+) adults in North-West Province, South Africa. In this cross-sectional study, dietary and nutrient intakes were assessed with Quantitative Food Frequency Questionnaire (QFFQ) and FoodFinder software, respectively. Dietary patterns were determined using Principal Component Analysis. Participants’ scores for the dietary patterns were related to nutrient intakes using Spearman Rank correlation and Generalised Linear Modelling (GENLIN). Four main dietary patterns were found in each population. The first three patterns were similar between the HIV- and HIV+ populations: “animal-based”, associated with intake of foods of animal origin; “recommended” associated with a varied diet; and “staple-based”. The fourth pattern was described as either ‘eggs-and-breakfast-cereals’ for the HIV- group or ‘legumes-and-vegetables’ for HIV+ group. Scores for animal-based pattern showed strongest correlations (r) with nutrient intakes for both populations, notably zinc (r=0.54), calcium (r=0.5), potassium (r=0.54), vitamin A (r=0.5), and vitamin C (r=0.5), (p<0.001 for all). In the HIV+ group, the legumes-and-vegetables pattern was strongly associated with energy (r=0.64), vitamins D (r=0.51), E (0.51) and B1 (r=0.55) (p<0.001 for all). Compared with the other patterns, the Staple-based and the recommended patterns showed the weakest associations with nutrient intakes. Generalised Linear Modelling confirmed stronger positive linear associations between scores of the animal-based diet and nutrients intake, compared with the other patterns. The findings suggest that the animal-based pattern was strongly associated with nutrients intake in both HIV + and HIV- populations. This raises the need for studies into dietary recommendations for promoting nutritional wellbeing for PLWHA in sub-Saharan Africa.Keywords: Dietary patterns; HIV/AIDS; THUSA, Nutrient

    Impact of common mental disorders during childhood and adolescence on secondary school completion

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    There are few data from South Africa and other low- and middle-income countries on how mental disorders in childhood and adolescence may influence different aspects of socio-economic position, including educational attainment. We examined the association between early-onset disorders and subsequent educational achievement in a nationallyrepresentative sample of 4 351 South African adults. After adjusting for participant demographic characteristics and traumatic life events, post-traumatic stress disorder, major depressive disorder and substance-related disorders were each associated with increased odds of failing to complete secondary education (odds ratios and 95% confidenceintervals 2.3, 1.0 - 5.1; 1.7, 1.2 - 2.5, and 1.7, 1.2 - 2.5, respectively). These data point to the role that early-life mental disorders may play in educational achievement and subsequent socio-economic position over the life course

    Mental health service use among South Africans for mood, anxiety and substance use disorders

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    Background. Europe and North America have low rates of mental health service use despite high rates of mental disorder. Little is known about mental health service use among South Africans.Design. A nationally representative survey of 4 351 adults. Twelve-month DSM-IV (Diagnostic and Statistical Manual, 4th edition) diagnoses, severity, and service utilisation were determined using the World Health Organization Composite International Diagnostic Interview (CIDI). Twelve-month treatment was categorised by sector and province. South Africans in households and hostel quarters were interviewed between 2002 and 2004 in all nine provinces.Outcome measures. 4 317 respondents 18 years and older wereanalysed. Bivariate logistic regression models predicted (i) 12-month treatment use of service sectors by gender, and (ii) 12-month treatment use by race by gender.Results. Of respondents with a mental disorder, 25.2% had sought treatment within the previous 12 months; 5.7% had used any formal mental health service. Mental health service use was highest for adults with mood and anxiety disorders, and among those with a mental disorder it varied by province, from 11.4% (Western Cape) to 2.2% (Mpumalanga). More women received treatment, and this was largelyattributable to higher rates of treatment in women with mood disorders. Age, income, education and marital status were not significantly associated with mental health service use. Race was associated with the treatment sector accessed in those with a mental disorder.Conclusions. There is a substantial burden of untreated mental disorders in the South African population, across all provinces and even in those with substantial impairment. Greater allocation of resources to mental health services and more community awareness initiatives are needed to address the unmet need

    Igneous activity in the Bornu Basin, onshore NE Nigeria; implications for opening of the South Atlantic

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    The structure of igneous plumbing systems in circum-South Atlantic, intra-continental rift basins (e.g. the West and Central African Rift Systems) remains enigmatic owing to poor subsurface data coverage and quality. How magmatism in these basins related to the opening of the South Atlantic is thus poorly understood. We integrate 2D and 3D seismic reflection data (c. 27 600 km2), data from 23 boreholes, and field observations from the Bornu Basin and Upper Benue Trough, onshore NE Nigeria, to examine the timing and development of igneous bodies possibly related to opening of the South Atlantic. We identify numerous sills, which typically have saucer-shaped and en echelon morphologies, and extrusive volcanic cones. The igneous rocks are alkali basalts and dolerites. Seismic-stratigraphic relationships indicate that emplacement occurred in the Early Cretaceous (Albian to Cenomanian; c. 120 Ma), Late Cretaceous (Santonian to early Campanian; c. 83 Ma) and Cenozoic (Miocene; c. 22 Ma). Magmatism was broadly coeval with major plate boundary interactions, characterized by major azimuthal changes in fracture zones in the developing South Atlantic Ocean. The broad temporal correlation between intra-continental rift basin magmatism and plate boundary interactions suggests that periods of magma emplacement may have, in some way, been instigated by stress dissipation into intra-continental rift basins

    Some Variations on Maxwell's Equations

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    In the first sections of this article, we discuss two variations on Maxwell's equations that have been introduced in earlier work--a class of nonlinear Maxwell theories with well-defined Galilean limits (and correspondingly generalized Yang-Mills equations), and a linear modification motivated by the coupling of the electromagnetic potential with a certain nonlinear Schroedinger equation. In the final section, revisiting an old idea of Lorentz, we write Maxwell's equations for a theory in which the electrostatic force of repulsion between like charges differs fundamentally in magnitude from the electrostatic force of attraction between unlike charges. We elaborate on Lorentz' description by means of electric and magnetic field strengths, whose governing equations separate into two fully relativistic Maxwell systems--one describing ordinary electromagnetism, and the other describing a universally attractive or repulsive long-range force. If such a force cannot be ruled out {\it a priori} by known physical principles, its magnitude should be determined or bounded experimentally. Were it to exist, interesting possibilities go beyond Lorentz' early conjecture of a relation to (Newtonian) gravity.Comment: 26 pages, submitted to a volume in preparation to honor Gerard Emch v. 2: discussion revised, factors of 4\pi corrected in some equation

    Microphone handling noise : measurements of perceptual threshold and effects on audio quality

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    A psychoacoustic experiment was carried out to test the effects of microphone handling noise on perceived audio quality. Handling noise is a problem affecting both amateurs using their smartphones and cameras, as well as professionals using separate microphones and digital recorders. The noises used for the tests were measured from a variety of devices, including smartphones, laptops and handheld microphones. The signal features that characterise these noises are analysed and presented. The sounds include various types of transient, impact noises created by tapping or knocking devices, as well as more sustained sounds caused by rubbing. During the perceptual tests, listeners auditioned speech podcasts and were asked to rate the degradation of any unwanted sounds they heard. A representative design test methodology was developed that tried to encourage everyday rather than analytical listening. Signal-to-noise ratio (SNR) of the handling noise events was shown to be the best predictor of quality degradation. Other factors such as noise type or background noise in the listening environment did not significantly affect quality ratings. Podcast, microphone type and reproduction equipment were found to be significant but only to a small extent. A model allowing the prediction of degradation from the SNR is presented. The SNR threshold at which 50% of subjects noticed handling noise was found to be 4.2 ± 0.6 dBA. The results from this work are important for the understanding of our perception of impact sound and resonant noises in recordings, and will inform the future development of an automated predictor of quality for handling noise

    Waterpipe smoking in students: Prevalence, risk factors, symptoms of addiction, and smoke intake. Evidence from one British university

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    Background: Anecdotal reports suggest waterpipe smoking is becoming common in students in western countries. The aim was to examine prevalence, risk factors, symptoms of addiction, and smoke intake. Methods: This was a cross-sectional survey of students with subsidiary survey of regular waterpipe user and survey of exhaled carbon monoxide (CO) before and after waterpipe smoking in customers of a waterpipe café. 937 students of Birmingham University completed the initial survey with a follow up of 21 regular waterpipe smokers. 63 customers of a waterpipe café near the University completed the study of CO intake. Results: 355 (37.9%, 95% confidence intervals (CI) 34.8 to 41.1%) students had tried waterpipes,the prevalence of trying rising with duration at University. 75 (8.0%, 95%CI 6.4 to 10.0%) were regular smokers, similar to the prevalence of cigarette smoking (9.4%). Although cigarette smoking was the major risk factor for being a regular waterpipe smoker, odds ratio (95%CI) 2.77 (1.52 to 5.06), 65% of waterpipe smokers did not smoke cigarettes. Seven of 21 (33.3%) regular waterpipe smokers experienced cravings. Nearly all regular waterpipe users thought it less harmful than smoking cigarettes. The mean (standard deviation) rise in CO was 37.4 (25.8)ppm, nearly twice as high as a typical cigarette smoker seeking cessation treatment. Conclusion: Waterpipe smoking is a common part of student culture in one British university, as in the Middle East and in the United States. It poses a potential threat to public health, with evidence of dependence and high smoke intake
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