8,022 research outputs found
Sustainable and renewable hydrogen production from recycled aluminum
The whole world has been suffering strong consequences related to climate change. The intense use of fossil fuels in the chemical and automotive industries have put the environment in jeopardy. Thus, the industry has achieved a point of no return and it is urgent the development of renewable and sustainable technologies. Hydrogen has been pointed as a key component of the new era in industry since it can be produced in a clean and sustainable way. Currently the development of hydrogen fuel cells technology has put the automotive sector ahead of the chemical industries in relation to studies regarding the hydrogen production. Chemical industries produce hydrogen with technologies reliant on fossil fuels while the automotive sector has been looking for renewable forms of hydrogen generation. Trains powered by hydrogen fuel cells are a reality in Europe, for instance. Hydrogen generation technological advances must match the pace of the development of fuel cells electrical vehicles in order to the environmental goals and widespread application of fuel cell systems to be achieved. The present study addresses the hydrogen generation from the spontaneous reaction between aluminum and aqueous solution of sodium hydroxide. Aluminum is a metal that presents high exergetic value and can be recycled several times without losing its thermo-mechanical properties. That makes the use of aluminum especially appealing. It will make hydrogen generation a cleaner and more affordable process. Our findings demonstrate that it is possible to predict the kinetic behavior of the reaction using data obtained by the conductometric method. Graphs of electrical conductivity vs time show that is possible to verify the order of the reaction. We will present concepts of kinetic, thermodynamic and transport phenomena of the reaction between solid recycled aluminum and sodium hydroxide in an aqueous solution. The knowledge acquired throughout this study will contribute to the development of a new reactor and as a consequence, a new renewable and sustainable industrial system of hydrogen generation
What do teachers want? Professional development opportunities for instructors of Portuguese as a heritage language
Understanding teachers’ thoughts and beliefs may be a tool to help prepare teacher training programs. Community-based school
teachers, especially those who work with less commonly taught
languages, do not have frequent access to professional development opportunities. Faced with the varied and specific needs of heritage learners, these instructors, who may not have received previous training in language teaching, may find their challenges quite daunting. Given those challenges, they tend to welcome the chance to attend events that help them in their teaching practice. Through a survey about perceptions and beliefs, this study shows that some workshops and other professional development opportunities held by consulates and universities may be of little relevance to the realities faced by teachers who work with heritage LCTLs. Our findings suggest that teacher training programs may prove to be an invaluable tool if they are not episodic, but rather prolonged and based on instructors’ expressed needs
Dose-response curves of Lolium multiflorum biotypes resistant and susceptible to clethodim.
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Avaliação de carbono e nitrogênio em perfis de solos sob diferentes sistemas de uso da terra, em Ponta Grossa, PR.
Em solos agrícolas, os estoques de C e N são afetados pelo uso da terra e pelas práticas de manejo, assim como pela quantidade de resíduos aportados anualmente na superfície do solo. Sistemas agroflorestais ou integrados têm o potencial de aumentar a fertilidade do solo e o sequestro de carbono e reduzir os processos erosivos. O objetivo deste estudo foi avaliar os estoques de C e N em cinco diferentes sistemas de uso da terra, incluindo dois sistemas integrados: sistema integrado lavoura-pecuária (iLP), sistema integrado lavoura-pecuária-floresta (iLPF), plantio de Eucaliptus dunnii (E), lavoura em plantio direto (L) e campo nativo (CN). As maiores diferenças significativas entre os teores de C e N nos diferentes sistemas de uso da terra estão nas camadas até 10 cm de profundidade, embora existam pequenas diferenças nos teores de C nas camadas mais profundas
Depression and Oral FTC/TDF Pre-exposure Prophylaxis (PrEP) Among Men and Transgender Women Who Have Sex With Men (MSM/TGW).
We conducted a longitudinal and cross-sectional analysis of depressive symptomology in iPrEx, a randomized, placebo-controlled trial of daily, oral FTC/TDF HIV pre-exposure prophylaxis (PrEP) in men and transgender women who have sex with men. Depression-related adverse events (AEs) were the most frequently reported severe or life-threatening AEs and were not associated with being randomized to the FTC/TDF arm (152 vs. 144 respectively OR 0.66 95 % CI 0.35-1.25). Center for Epidemiologic Studies Depression scale (CES-D) and a four questions suicidal ideation scale scores did not differ by arm. Participants reporting forced sex at anal sexual debut had higher CES-D scores (coeff: 3.23; 95 % CI 1.24-5.23) and were more likely to have suicidal ideation (OR 2.2; 95 % CI 1.09-4.26). CES-D scores were higher among people reporting non-condom receptive anal intercourse (ncRAI) (OR 1.46; 95 % CI 1.09-1.94). We recommend continuing PrEP during periods of depression in conjunction with provision of mental health services
Assessment of the proportionality of skin folds between professional footballers and alternate, Peruvian
El objetivo del estudio fue proporcionar información descriptiva sobre las diferencias de proporcionalidad de la masa corporal y pliegues cutáneos entre jugadores titulares y reservas en función de la posición de juego. Fueron seleccionados de forma no probabilística 4 clubes profesionales de Primera División del Fútbol Profesional Peruano, considerándose 44 titulares y 28 reservas. Se evaluó la masa corporal, estatura, seis pliegues cutáneos, determinándose la proporcionalidad corporal por medio de la estrategia del Phantom. Los resultados muestran que la proporcionalidad de la masa corporal y los pliegues cutáneos es similar, tanto de forma general y por ubicación de juego, no existiendo diferencias significativas entre las posiciones de juego y entre titulares y suplentes. En conclusión, todos los jugadores, independientemente de la posición de juego y la titularidad y/o suplencia muestran similares valores de proporcionalidad corporal y de pliegues cutáneos, mostrando en general altos valores de masa corporal y bajos niveles de tejido adiposo.The aim of the study was to provide descriptive information about the differences in proportionality of body mass and skinfold thickness between starters and reserves as playing position. They were selected in a non-probabilistic 04 professional clubs in the First Division of Professional Football Peruvian, considering 44 starters and 28 reserves. We assessed body mass, height, six skinfolds, body proportionality determined by the strategy of the Phantom. The results show that the proportionality of body mass and skinfold is similar, both generally and by playing position, with no significant differences between playing positions and titular or alternate players. In conclusion, all players regardless of playing position and title and/or substitution proportionality show similar values and skinfold body, showing generally high body mass values and low levels of fat.Peer Reviewe
Effects of pasture type and level of concentrate supplementation on quality and fatty acid profile of lamb meat.
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Expression of sugarcane genes induced by inoculation with Gluconacetobacter diazotrophicus and Herbaspirillum rubrisubalbicans
Several Brazilian sugarcane varieties have the ability to grow with little addition of inorganic nitrogen fertilizers, showing high contributions of Biological Nitrogen Fixation (BNF). A particular type of nitrogen-fixing association has been described in this crop, where endophytic diazotrophs such as Gluconacetobacter diazotrophicus and Herbaspirillum spp. colonize plant tissues without causing disease symptoms. In order to gain insight into the role played by the sugarcane in the interaction between this plant and endophytic diazotrophs, we investigated gene expression profiles of sugarcane plants colonized by G. diazotrophicus and H. rubrisubalbicans by searching the sugarcane expressed sequence tag SUCEST Database (http://sucest.lad.ic.unicamp.br/en/). We produced an inventory of sugarcane genes, candidates for exclusive or preferential expression during the nitrogen-fixing association. This data suggests that the host plant might be actively involved in the establishment of the interaction with G. diazotrophicus and H. rubrisubalbicans.Diversos genótipos brasileiros de cana-de-açúcar são capazes de crescer com baixa adição de adubos nitrogenados, obtendo elevadas contribuições da Fixação Biológica de Nitrogênio (FBN). Um tipo especial de associação com bactérias fixadoras de nitrogênio foi descrito em cana-de-açúcar, onde as bactérias endofíticas, como Gluconacetobacter diazotrophicus e Herbaspirillum spp., colonizam o interior dos tecidos vegetais, sem causar sintomas de doença. Com o objetivo de tentar entender o papel da cana-de-açúcar nesse tipo de associação, nós investigamos os perfis de expressão gênica de plantas colonizadas pelos diazotróficos endofíticos, usando o banco de dados do SUCEST. Um catálogo com os genes de cana-de-açúcar que são candidatos a se expressar exclusivamente ou preferencialmente durante a associação foi gerado. Esses dados preliminares sugerem que a cana-de-açúcar deve ter uma participação ativa na interação, respondendo a diversos processos metabólicos durante a associação.199206Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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