16,074 research outputs found
Light Rechargeable Lithium-Ion Batteries Using V2O5 Cathodes
Solar energy is one of the most actively pursued renewable energy sources, but like many other sustainable energy sources, its intermittent character means solar cells have to be connected to an energy storage system to balance production and demand. To improve the efficiency of this energy conversion and storage process, photobatteries have recently been proposed where one of the battery electrodes is made from a photoactive material that can directly be charged by light without using solar cells. Here, we present photorechargeable lithium-ion batteries (Photo-LIBs) using photocathodes based on vanadium pentoxide nanofibers mixed with P3HT and rGO additives. These photocathodes support the photocharge separation and transportation process needed to recharge. The proposed Photo-LIBs show capacity enhancements of more than 57% under illumination and can be charged to ∼2.82 V using light and achieve conversion efficiencies of ∼2.6% for 455 nm illumination and ∼0.22% for 1 sun illumination
The politics of alcohol policy in Nigeria: a critical analysis of how and why brewers use strategic ambiguity to supplant policy initiatives
The global call by the World Health Assembly (WHA) to control the rising alcohol-related problems caused by harmful consumption through policy became necessary in 2005 due to the recognition of the fact that many countries did not have alcohol policies. This gave rise to the adoption of a ten-point policy strategy by the World Health Organization (WHO) Member States in 2010. Against this backdrop, many countries adopted alcohol policies to reduce harmful alcohol consumption. Nigeria was one of the WHO Member Countries that adopted the resolution. Nigeria is among the 30 countries with the highest per capita consumption and alcohol-related problems, yet has not formulated alcohol policy to date. This paper draws on Eisenberg’s Strategic Ambiguity Model to explore the role of brewers in supplanting alcohol policy initiatives in Nigeria. It argues that the leading alcohol producers in Nigeria have been the main reason alcohol policies have not been formulated. The article focuses on why their campaigns for responsible drinking, promotions, sponsorships and ‘strategic social responsibilities’ may have increased since the WHA made the call and the WHO adopted the resolution in 2010. It concludes by arguing that there is an urgent need to formulate policies drawing from the WHO resolution to curtail the activities of these brewers and reduce harmful consumption
Nuclear Matter and Nuclear Dynamics
Highlights on the recent research activity, carried out by the Italian
Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be
presented.Comment: Proceedings of the 12th Conference on Problems in Theoretical Nuclear
Physics, to appear in Journal of Physics, Conference Serie
Intertwining Relations for the Deformed D1D5 CFT
The Higgs branch of the D1D5 system flows in the infrared to a
two-dimensional N=(4,4) SCFT. This system is believed to have an "orbifold
point" in its moduli space where the SCFT is a free sigma model with target
space the symmetric product of copies of four-tori; however, at the orbifold
point gravity is strongly coupled and to reach the supergravity point one needs
to turn on the four exactly marginal deformations corresponding to the blow-up
modes of the orbifold SCFT. Recently, technology has been developed for
studying these deformations and perturbing the D1D5 CFT off its orbifold point.
We present a new method for computing the general effect of a single
application of the deformation operators. The method takes the form of
intertwining relations that map operators in the untwisted sector before
application of the deformation operator to operators in the 2-twisted sector
after the application of the deformation operator. This method is
computationally more direct, and may be of theoretical interest. This line of
inquiry should ultimately have relevance for black hole physics.Comment: latex, 23 pages, 3 figure
Towards segmentation and spatial alignment of the human embryonic brain using deep learning for atlas-based registration
We propose an unsupervised deep learning method for atlas based registration
to achieve segmentation and spatial alignment of the embryonic brain in a
single framework. Our approach consists of two sequential networks with a
specifically designed loss function to address the challenges in 3D first
trimester ultrasound. The first part learns the affine transformation and the
second part learns the voxelwise nonrigid deformation between the target image
and the atlas. We trained this network end-to-end and validated it against a
ground truth on synthetic datasets designed to resemble the challenges present
in 3D first trimester ultrasound. The method was tested on a dataset of human
embryonic ultrasound volumes acquired at 9 weeks gestational age, which showed
alignment of the brain in some cases and gave insight in open challenges for
the proposed method. We conclude that our method is a promising approach
towards fully automated spatial alignment and segmentation of embryonic brains
in 3D ultrasound
Analysis of the Reaction Rate Coefficients for Slow Bimolecular Chemical Reactions
Simple bimolecular reactions are analyzed
within the framework of the Boltzmann equation in the initial stage of a
chemical reaction with the system far from chemical equilibrium. The
Chapman-Enskog methodology is applied to determine the coefficients of the
expansion of the distribution functions in terms of Sonine polynomials for
peculiar molecular velocities. The results are applied to the reaction
, and the influence of the non-Maxwellian
distribution and of the activation-energy dependent reactive cross sections
upon the forward and reverse reaction rate coefficients are discussed.Comment: 11 pages, 5 figures, to appear in vol.42 of the Brazilian Journal of
Physic
Papel da análise discriminante no aprimoramento da avaliação da satisfação dos usuários
OBJECTIVE: To test discriminant analysis as a method of turning the information of a routine customer satisfaction survey (CSS) into a more accurate decision-making tool. METHODS: A 7-question, 10-multiple choice, self-applied questionnaire was used to study a sample of patients seen in two outpatient care units in ValparaÃso, Chile, one of primary care (n=100) and the other of secondary care (n=249). Two cutting points were considered in the dependent variable (final satisfaction score): satisfied versus unsatisfied, and very satisfied versus all others. Results were compared with empirical measures (proportion of satisfied individuals, proportion of unsatisfied individuals and size of the median). RESULTS: The response rate was very high, over 97.0% in both units. A new variable, medical attention, was revealed, as explaining satisfaction at the primary care unit. The proportion of the total variability explained by the model was very high (over 99.4%) in both units, when comparing satisfied with unsatisfied customers. In the analysis of very satisfied versus all other customers, significant relationship was identified only in the case of the primary care unit, which explained a small proportion of the variability (41.9%). CONCLUSIONS: Discriminant analysis identified relationships not revealed by the previous analysis. It provided information about the proportion of the variability explained by the model. It identified non-significant relationships suggested by empirical analysis (e.g. the case of the relation very satisfied versus others in the secondary care unit). It measured the contribution of each independent variable to the explanation of the variation of the dependent one.OBJETIVO: Testar a análise discriminante como um método de transformar a informação obtida num inquérito de satisfação dos usuários de rotina numa acurada ferramenta de tomada de decisão. MÉTODOS: Utilizou-se questionário auto-aplicável com sete questões de dez opções numa amostra dos pacientes atendidos em duas unidades ambulatórias públicas, em ValparaÃso, Chile, sendo uma de cuidados primários (n=100) e a outra de atenção secundária (n=249). Utilizaram-se dois pontos de corte na variável dependente (Ãndice final de satisfação): satisfeitos vs insatisfeitos e muito satisfeitos vs os demais. Os resultados foram comparados com medidas empÃricas habitualmente utilizadas (proporção de satisfeitos, proporção de insatisfeitos e dimensão da mediana). RESULTADOS: O nÃvel de resposta foi muito elevado (sempre acima de 97,0%). Uma variável adicional revelou-se (atendimento médico), explicando a satisfação com o atendimento na unidade primária. Ao comparar satisfeitos com insatisfeitos, a proporção total da variabilidade explicada pelo modelo foi muito elevada (acima de 99,4%) em ambas unidades. Ao comparar muito satisfeitos com os demais, observou-se relação significativa apenas no caso da unidade primária. Explicou-se uma baixa proporção da variabilidade (41,9%). CONCLUSÕES: A análise discriminante revelou relações não percebidas pela análise empÃrica e indicou a proporção exata da variabilidade explicada pelo modelo utilizado. A técnica afastou como não significativas relações sugeridas pela análise empÃrica (por exemplo, muito satisfeitos versus os demais no caso da unidade secundária). A técnica permitiu medir a intensidade da contribuição de cada variável na explicação da variação da satisfação
Loss of HIV-infected patients on potent antiretroviral therapy programs in Togo: risk factors and the fate of these patients
Introduction: National programs are facing challenges of loss to follow-up of people living with HIV/AIDS (PLWHA) on antiretroviral therapy (ART). We sought to identify risk factors associated with early loss to follow-up among HIV-infected patients on ART in Togo and the outcome of such patients. Methods: This was a retrospective cross-sectional study using medical records of all patients older than age 15 years enrolled at 28 treatment centers who were on ART programs and who were lost to follow-up from 2008 to 2011. Results: Of the 16,617 patients on ART, 1,216 (7.3%) were lost to follow-up. Most (94.1%) were infected with HIV-1 and 32.6% were in WHO stage III or IV. The median CD4 count was 118/mm3 (IQR: 58-178 cells/mm3). No telephone number was mentioned in the medical records of 212 patients. Of the 1004 patients whose phone number was listed, 802 patients (79.9%) were not reachable on the recorded number, 114 patients (11.4%) were alive and 88 patients (8.8%) had died. In multivariate analysis, factors associated with loss to follow-up during the first 6 months of ART were: age below 35 years (OR=1.6; 95%CI: 1.2-2.2), female sex (OR=1.8; 95%CI: 1.3-2.5), WHO stage III or IV (OR=1.7; 95%CI: 1.3-2.2), existence of an opportunistic infection (OR=2.3; 95%CI: 1.5-3.1), and follow-up in a public centre (OR=1.9; 95%CI: 1.2-3.3). Conclusion: This study identified several factors associated with lost to follow-up during the first 6 months of ART, and confirmed high mortality among these patients. The National AIDS Program should strengthen medical support of PLWHA in Togo including active case follow-up.Key words: Africa, HIV, human immunodeficiency virus, lost to follow-up, people living with HIV, Tog
- …