552 research outputs found
On a dissipative Gross-Pitaevskii-type model for exciton-polariton condensates
We study a generalized dissipative Gross-Pitaevskii-type model arising in the
description of exciton-polariton condensates. We derive global in-time
existence results and various a-priori estimates for this model posed on the
one-dimensional torus. Moreover, we analyze in detail the long-time behavior of
spatially homogenous solutions and their respective steady states and present
numerical simulations in the case of more general initial data. We also study
the convergence to the corresponding adiabatic regime, which results in a
single damped-driven Gross-Pitaveskii equation.Comment: 25 pages, 11 figure
Unsupervised learning as a complement to convolutional neural network classification in the analysis of saccadic eye movement in spino-cerebellar ataxia type 2
IWANN es un congreso internacional que se celebra bienalmente desde 1991. Su campo de estudio se centra en la fundamentación y aplicación de las distintas técnicas de Inteligencia Computacional : Redes Neuronales Artificiales, Algoritmos Genéticos, Lógica Borrosa, Aprendizaje Automåtico. En esta edición han participado 150 investigadores.This paper aims at assessing spino-cerebellar type 2 ataxiaby classifying electrooculography records into registers corresponding to healthy, presymptomatic and ill individuals. The primary used technique is the convolutional neural network applied to the time series of eye movements, called saccades. The problem is exceptionally hard, though, because the recorded saccadic movements for presymptomatic cases often do not substantially di er from those of healthy individuals. Precisely
this distinction is of the utmost clinical importance, since early intervention on presymptomatic patients can ameliorate symptoms or at least slow their progression. Yet, each register contains a number of saccades that, although not consistent with the current label, have not been considered indicative of another class by the examining physicians. As a consequence, an unsupervised learning mechanism may be more suitable to handle this form of misclassi cation. Thus, our proposal introduces the
k-means approach and the SOM method, as complementary techniques to analyse the time series. The three techniques operating in tandem lead to a well performing solution to this diagnosis problem.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech.
Universidad de Granada, Universitat PolitĂšcnica de Catalunya, Universidad de Las Palmas de Gran Canaria, Springe
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Optimization of environmental factors for effective detection of Bean yellow mosaic virus in Verbena x hybrida
Horticultural and nursery crops are the leading agricultural commodity in Oregon. Among currently grown nursery plants, Verbena x hybrida is a staple ornamental. It is grown and shipped worldwide, thus requiring a high level of certainty concerning the plantsâ health and potential viability. V. x hybrida cultivars have been infected by a potyvirus that has been a sporadic but chronic problem in the floriculture industry for many years. Within the plant, detectable potyvirus titers fluctuate widely, making it difficult to detect in commercial nurseries. Virus detection can also be affected by changing environmental conditions, which also influence virus levels. The objectives of this study were to determine the environmental conditions that optimized detectable virus levels, to observe if the virus could be detected in tissue culture plantlets, to establish the earliest age at which plants could be accurately assayed, and to ascertain the most sensitive and reliable testing method for virus detection. The V. x hybrida cultivars in the study were infected âLavender Shadesâ and non-infected âTwilight with Blue Eye.â Plants were tissue cultured or potted and placed in growth chambers at three temperatures with constant photoperiod and then at three photoperiods with constant temperature. The Enzyme-linked Immunosorbent Assay (ELISA) and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) were used as the testing methods. Tests were performed at two week intervals for a duration of two months in each of the two growth chamber experiments. The resulting data support the conclusion that V. x hybrida plants should be grown in pots at 26°C and 16 or 20 hour photoperiod for at least 6 weeks before testing with RT-PCR for the most accurate detection of virus
Family, Gender, and Population Policy: Views from the Middle East [Arabic]
This paper explores the relevance of international debates to the realities of the Middle East, an important but understudied region that has often been subject to stereotyping. The regionâs wealth of traditions and diverse contemporary experience offer insights to those who venture beyond the surface appearance. This paper provides a broad introduction to the connections between family, gender, and population policy in the Middle East. It is based on studies by a diverse group of Middle East scholars and the discussions they generated in Cairo at an international symposium sponsored by the Population Council in February 1994. The paper was written prior to the historic UN International Conference on Population and Development in Egypt, in the hope both of increasing understanding of an important region of the world and refining our grasp of international issues
Understanding the gender disparity in HIV infection across countries in sub-Saharan Africa: Evidence from the Demographic and Health Surveys
Women in sub-SaharanAfrica bear a disproportionate burden of human immunodeficiency virus (HIV) infections, which is exacerbated by their role in society and biological vulnerability. The specific objectives of this article are to (i) determine the extent of gender disparity in HIV infection; (ii) examine the role of HIV behaviour factors on the gender disparity and (iii) establish how the gender disparity varies between individuals of different characteristics and across countries. The analysis involves multilevel logistic regression analysis applied to pooledDemographic andHealth Surveys data from 20 countries in sub-Saharan Africa conducted during 2003â2008. The findings suggest that women in sub- Saharan Africa have on average a 60%higher risk of HIV infection than their male counterparts. The risk for women is 70%higher than their male counterparts of similar sexual behaviour, suggesting that the observed gender disparity cannot be attributed to sexual behaviour. The results suggest that the risk ofHIV infection among women (compared to men) across countries in sub-Saharan Africa is further aggravated among those who are younger, in female-headed households, not in stable unions or marital partnerships or had an earlier sexual debut.â acquired immune deficiency syndrome (AIDS) awareness and sexua
Expanding ART for Treatment and Prevention of HIV in South Africa: Estimated Cost and Cost-Effectiveness 2011-2050
Uptake of HIV testing in Burkina Faso: an assessment of individual and community-level determinants
Factors influencing uptake of voluntary counselling and testing services for HIV/AIDS in the Lower Manya Krobo Municipality (LMKM) in the Eastern Region of Ghana: a cross-sectional household survey
Background
Voluntary counselling and testing (VCT) is one of the nine strategies recommended for prevention and control of HIV globally. In this study, we assessed the awareness and utilisation of VCT services among residents of the Lower Manya Krobo Municipality (LMKM) in the Eastern Region of Ghana.
Methods
A population-based descriptive cross-sectional survey was conducted with 200 participants, aged between 18 and 55 years. Participants were recruited using cluster and simple random techniques to take part in the survey. Data was analysed descriptively, as well as using regression analysis approach.
Results
Ninety-one percent of the respondents surveyed were aware of VCT services for HIV/AIDS. Seventy percent (70 %) have used VCT service in the last 12 months prior to the survey. Of this proportion, 97 % were satisfied with the quality of VCT services offered and indicated their willingness to recommend the service to others. Participants desire to know their HIV status (40 %), referral by health workers (25 %), and participants who wanted to get married (11 %) were the main reasons for increased uptake. Participants who had formal education, primary (ORâ=â1.8 (95 % CI 1.25â2.84)), junior high school (ORâ=â2.3 (95 % CI 1.54â3.37)), senior high school (ORâ=â2.8 (95 % CI 1.73â4.78)), and tertiary (ORâ=â3.4 (95 % CI 1.98â8.42)), had increased chance of using VCT service compared with participants who had no education (pâ<â0.001). Reasons for non-utilisation of VCT service were lack of awareness of the VCT service in the area (32 %), fear of being stigmatised (53 %), and the belief that HIV/AIDS cannot be cured and therefore the lack of need (5 %).
Conclusions
Although awareness and utilisation of VCT service rates were reportedly high, more efforts need to be done in order to increase awareness and promote utilisation. HIV/AIDS educational campaign programmes need to be strongly pursued, with emphasis on the benefits of VCT services. This has the potential of reducing stigma and increase utilisation
Clinical Ethics in Gabon: The Spectrum of Clinical Ethical Issues Based on Findings from In-Depth Interviews at Three Public Hospitals
Introduction Unlike issues in biomedical research ethics, ethical challenges arising in daily clinical care in Sub-Saharan African countries have not yet been studied in a systematic manner. However this has to be seen as a distinct entity as we argue in this paper. Our aim was to give an overview of the spectrum of clinical ethical issues and to understand what influences clinical ethics in the Sub-Saharan country of Gabon. Materials and Methods In-depth interviews with 18 health care professionals were conducted at three hospital sites in Gabon. Interview transcripts were analyzed using a grounded theory approach (open and axial coding),giving a qualitative spectrum of categories for clinical ethical issues. Validity was checked at a meeting with study participants and other health care experts in Gabon after analysis of the data. Results Twelve main categories (with 28 further-specified subcategories) for clinical ethical issues were identified and grouped under three core categories: A) micro level: "confidentiality and information","interpersonal, relational and behavioral issues","psychological strain of individuals",and "scarce resources";B) meso level: "structural issues of medical institutions","issues with private clinics","challenges connected to the family",and "issues of education, training and competence";and C) macro level: "influence of society, culture, religion and superstition","applicability of western medicine","structural issues on the political level",and "legal issues". Discussion Interviewees reported a broad spectrum of clinical ethical issues that go beyond challenges related to scarce financial and human resources. Specific socio-cultural, historical and educational backgrounds also played an important role. In fact these influences are central to an understanding of clinical ethics in the studied local context. Further research in the region is necessary to put our study into perspective. As many participants reported a lack of awareness of ethical issues amongst other health care professionals in daily clinical practice, we suggest that international organizations and national medical schools should consider infrastructure and tools to improve context-sensitive capacity building in clinical ethics for Sub-Saharan African countries like Gabon
The Sneeuberg: A new centre of floristic endemism on the Great Escarpment, South Africa
The Sneeuberg mountain complex (Eastern Cape) comprises one of the most prominent sections of the Great Escarpment in southern Africa but until now has remained one of the botanically least known regions. The Sneeuberg is a discrete orographical entity, being delimited in the east by the Great Fish River valley, in the west by the Nelspoort Interval, to the south by the Plains of Camdeboo, and to the north by the Great Karoo pediplain. The highest peaks range from 2278 to 2504 m above sea level, and the summit plateaux range from 1800 to 2100 m. Following extensive literature review and a detailed collecting programme, the Sneeuberg is reported here as having a total flora of 1195 species of which 107 (9%) are alien species, 33 (2.8%) are endemic, and 13 (1.1%) near-endemic. Five species previously reported as Drakensberg Alpine Centre (DAC) endemics are now known to occur in the Sneeuberg (representing range extensions of some 300â500 km). One-hundred-and-five species (8.8%) are DAC near-endemics, with the Sneeuberg being the western limit for most of these. Ten species (0.8%) represent disjunctions across the Karoo Interval from the Cape Floristic Region (CFR) to the Sneeuberg. In all, some 23 significant range extensions, eight new species, and several rediscoveries are recorded. We conclude by recognising the Sneeuberg as a new centre of endemism along the Great Escarpment, with floristic affinities with the Albany Centre and the DAC, and links to the CFR
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