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Modeling the links between young swimmers’ performance: energetic and biomechanic profiles

Barbosa, Tiago M.; Costa, M.J.; Marinho, D.A.; Coelho, Joel; Moreira, M.; Silva, A.J.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.144092%
The aim was to develop a path-flow analysis model for young swimmers’ performance based on biomechanical and energetic parameters, using structural equation modeling. Thirty-eight male young swimmers served as subjects. Performance was assessed by the 200-m freestyle event. For biomechanical assessment the stroke length, the stroke frequency and the swimming velocity were analyzed. Energetics assessment included the critical velocity, the stroke index and the propulsive efficiency. The confirmatory model explained 79% of swimming performance after deleting the stroke index-performance path, which was nonsignificant (SRMR = 0.06). As a conclusion, the model is appropriate to explain performance in young swimmers.

Relationships between energetic, stroke determinants, and velocity in butterfly

Barbosa, Tiago M.; Keskinen, K.L.; Fernandes, R.J.; Colaço, P.; Carmo, C.; Vilas-Boas, J.P.
Fonte: Georg Thieme Publicador: Georg Thieme
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.211133%
The purpose of this study was to identify the relationship between the bioenergetical and the biomechanical variables (stroke parameters), through a range of swimming velocities, in butterfly stroke. Three male and one female butterflier of international level were submitted to an incremental set of 200-m butterfly swims. The starting velocity was 1.18 m(.)s(-1) for the males and 1.03 m(.)s(-1) for the female swimmer. Thereafter, the velocity was increased by 0.05 m(.)s(-1) after each swim until exhaustion. Cardio-pulmonary and gas exchange parameters were measured breath by breath for each swim to analyze oxygen consumption and other energetic parameters by portable metabolic cart (K4b(2), Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyze blood lactate concentration (YSI 1500 L, Yellow Springs, US). Total energy expenditure energetic cost (E-tot), stroke frequency (SF), stroke length (SL), mean swimming velocity (V), and stroke index (SI) were Calculated for each lap and average for each 200-m stage. Correlation coefficients between E-tot and V...

The influence of anthropometric, kinematic and energetic variables and gender on swimming performance in youth athletes

Morais, Jorge E.; Garrido, N.; Marques, M.C.; Silva, A.J.; Marinho, D.A.; Barbosa, Tiago M.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.09733%
The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance...

Desenvolvimento e análise de um índice de sustentabilidade energética utilizando lógica fuzzy; Development and analysis to create an energy sustainability index using fuzzy logic

Santos, Francisco Carlos Barbosa dos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 08/11/2010 Português
Relevância na Pesquisa
47.037686%
A questão do Desenvolvimento Sustentável é um dos temas mais falados na atualidade, e a busca do seu entendimento um grande desafio aos pesquisadores. Mas buscar seu entendimento e as relações das dimensões que o compõe (dimensão econômica, social, ambiental e institucional) não é o único desafio. Mensurar o caminho do desenvolvimento de uma sociedade é um desafio igualmente grande, principalmente devido as intrincadas relações entre meio ambiente, sociedade e economia. Este trabalho apresenta uma nova abordagem na construção de um índice sintético de desenvolvimento sustentável do ponto de vista da sustentabilidade energética. Esta metodologia se baseou em arquétipos matemáticos estruturados na Lógica Fuzzy, permitindo assim incorporar novas bases de conhecimento, mesmo que com definições vagas. O resultado final é a criação de um Índice de Sustentabilidade Energética que pode ser acompanhado no tempo, e que permite comparações entre países, já que na sua construção utiliza-se a base de dados do Guia de Indicadores Energéticos de Desenvolvimento Sustentável da Agência Internacional de Energia Atômica, que apresenta uma metodologia mundialmente aceita de indicadores energéticos. Este índice foi concebido para se parecido com outros indicadores como Índice de Desenvolvimento Humano (IDH) elaborado pela Organização das Nações Unidas...

Características dos resíduos da colheita de madeira de eucalipto e pinus, submetidos ao tratamento térmico, com foco na aplicação energética; Characteristics of eucalyptus and pine harvest residues, submitted to thermal treatment, with focus on energetic application

Pincelli, Ana Lúcia Piedade Sodero Martins
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 21/10/2011 Português
Relevância na Pesquisa
27.288225%
No contexto mundial atual, a busca de fontes de energia renováveis e menos poluentes que o petróleo tornou-se inevitável. O uso da biomassa como fonte de energia é extremamente importante, devido principalmente ao seu caráter renovável e a sua abundância. Os resíduos florestais são cada vez mais preconizados como uma importante fonte de biomassa. Isto se deve a sua abundância, facilidade de aprovisionamento e baixo custo. Podemos citar, como exemplo, os resíduos gerados durante a colheita florestal (cascas, folhas, galhos, ponteiros, entre outros) e durante o processamento mecânico da madeira (costaneiras, aparas, pó de serra, entre outros). O uso deste tipo de material para fins energéticos vem crescendo, porém, há um grande espaço para melhorias a serem implementadas nesse campo, envolvendo o melhor conhecimento de suas características e o potencial de aplicação de processos para sua conversão em produtos mais otimizados em relação aos seus valores energéticos. Diante desse quadro, e em se considerando a madeira, surge a oportunidade para adoção de processos de tratamento térmico, para os quais já existem referências que indicam a ocorrência de mudanças nas características desse material, o que conduz à previsão de se poder obter resultados positivos em relação ao que se exige para usos energéticos. Além do tradicional e amplamente usado processo de secagem...

Influence of different doses of retinoic acid on cardiac remodeling

Freire, Cristiana M. M.; Azevedo, Paula S.; Minicucci, Marcos F.; Oliveira Junior, Silvio A.; Martinez, Paula F.; Novo, Rosangela; Chiuso-Minicucci, Fernanda; Matsubara, Beatriz B.; Matsubara, Luiz S.; Okoshi, Katashi; Novelli, Ethel L.; Zornoff, Leonardo
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 824-828
Português
Relevância na Pesquisa
27.144092%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Objective: The role of retinoic acid in promoting postnatal heart alterations is still unclear. The aim of this study was to evaluate whether the cardiac alterations caused by all-trans- retinoic acid (ATRA) in normal adult rat hearts are physiologic or pathologic and if these alterations are dose-dependent.Methods: Rats were allocated into a control group that received a diet without ATRA (n = 16), a group that received 0.3 mg of ATRA/kg of diet (n = 17), a group that received a diet containing 10 mg of ATRA/kg (n = 18), or a group that received 50 mg of ATRA/kg in the diet (n = 18). After 4 wk, the animals were evaluated echocardiographically, morphologically, and biochemically.Results: The 50-mg ATRA group presented cardiac hypertrophy with maintenance of cardiac geometry and increased systolic function, whereas diastolic function was similar to that of the control group. In addition, progressive increases in the ATRA dose resulted in gradual augmentations of left atrial diameter, left ventricular diastolic and systolic diameters, left ventricular mass index, cardiac output, cardiac index, and aortic velocity. The ATRA did not produce alterations in interferon-gamma and tumor necrosis factor-alpha cardiac levels...

Eficiência econômica e energética de sistemas de produção de mamona nos estados de Minas Gerais e Paraná

Silva, Gerson Henrique
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: xv, 129 f. : il. color, gráfs., tabs.
Português
Relevância na Pesquisa
27.288225%
Pós-graduação em Agronomia (Energia na Agricultura) - FCA; A crescente preocupação com o meio ambiente e, especificamente, com as mudanças climáticas globais, impõem a necessidade de diversificar a atual matriz energética, com prioridade para fontes renováveis e limpas. Diante disso, com a implementação do PNPB, procurou-se introduzir o biodiesel na matriz energética brasileira. Com a lei, o biodiesel necessário para a mistura, produzido preferencialmente a partir de matérias-primas produzidas por meio da agricultura familiar, recebe incentivos. Neste aspecto, a mamona por ser produzida principalmente por pequenos produtores, é uma das que são previstas para o uso na produção de biodiesel. Assim, este estudo tem por objetivo determinar a eficiência econômica e energética da cultura da mamona nas regiões Oeste e Centro Ocidental do Paraná e Zona da Mata e Sul de Minas Gerais. Na seleção dos produtores de mamona, aplicou-se o processo não probabilístico, especificamente, a amostra se deu por acessibilidade. Através do método de simulação de Monte Carlo, verificou-se as probabilidades de ocorrência dos índices de eficiência econômica, cultural e energética. Constatou-se, nesta pesquisa, que o sistema de produção das regiões Oeste e Centro Ocidental do Paraná na safra 2006/2007 não se mostrou rentável. O preço foi a variável que mais afetou a rentabilidade...

EFFECT OF FOOD SHORTAGE ON GROWTH, ENERGETIC RESERVES MOBILIZATION, AND WATER QUALITY IN JUVENILES OF THE REDCLAW CRAYFISH, CHERAX QUADRICARINATUS, REARED IN GROUPS

Stumpf, Liane; Castillo Diaz, Fernando; Elizabeth Viau, Veronica; Valenti, Wagner C.; Lopez Greco, Laura Susana
Fonte: Crustacean Soc Publicador: Crustacean Soc
Tipo: Artigo de Revista Científica Formato: 639-646
Português
Relevância na Pesquisa
37.211133%
The aim of this study is to analyze the impact of food shortage on growth performance, by means of energetic reserves (proteins, glycogen and lipids) mobilization and hepatopancreas cells analysis in C. quadricarinatus juveniles maintained in groups, as well as the effect on culture water quality. Two experiments were performed, each of them with two feeding regimes during 45 days. The Control feeding regime, in which crayfish were fed daily (once a day) throughout the experimental period (DF), and the Cyclic feeding regime, in which juveniles were fed for 2 or 4 days (once a day) followed by 2 or 4 days of food deprivation (2F/2D and 4F/4D, respectively) in repeated cycles. Cyclic feeding influenced growth, biochemical composition from hepatopancreas and muscle, and water quality. Juveniles cyclically fed were unable to maintain a normal growth trajectory during 45 days. Apparent feed conversion ratio, apparent protein efficiency ratio, hepatosomatic index and relative pleon mass were similar in cyclic and daily fed animals and no structural damage was found in the hepatopancreas of juveniles subjected to cyclic feeding. The novelty of this study was the significant accumulation of proteins in pleonal muscle in both cyclic feeding regimes (approx. 18%) suggesting that the storage of this constitutive material during food shortage may be an adaptation for a compensatory growth when food becomes abundant again. The cyclic feeding regimes had a positive effect on water quality decreasing inorganic nitrogen concentration. This was due to the reduction in the amount of animal excretes and feces in the group that received approx. 50% less feed. Additionally...

Identification of molecular and physiological responses to chronic environmental challenge in an invasive species The Pacific oyster, Crassostrea gigas

Clark, M. S.; Thorne, Michael A. S.; Amaral, Ana; Vieira, Florbela; Batista, Frederíco M.; Reis, João; Power, Deborah
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
27.144092%
Understanding the environmental responses of an invasive species is critical in predicting how ecosystem composition may be transformed in the future, especially under climate change. In this study, Crassostrea gigas, a species well adapted to the highly variable intertidal environment, was exposed to the chronic environmental challenges of temperature (19 and 24°C) and pH (ambient seawater and a reduction of 0.4 pH units) in an extended 3-month laboratory-based study. Physiological parameters were measured (condition index, shell growth, respiration, excretion rates, O:N ratios, and ability to repair shell damage) alongside molecular analyses. Temperature was by far the most important stressor, as demonstrated by reduced condition indexes and shell growth at 24°C, with relatively little effect detected for pH. Transcriptional profiling using candidate genes and SOLiD sequencing of mantle tissue revealed that classical “stress” genes, previously reported to be upregulated under acute temperature challenges, were not significantly expressed in any of the treatments, emphasizing the different response between acute and longer term chronic stress. The transcriptional profiling also elaborated on the cellular responses underpinning the physiological results...

Use of medicinal plant in the manufacturing of energetic cookies

Gonçalves,Édira Castello Branco de Andrade; Andrade,Roberta Melquiades Silva de
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 Português
Relevância na Pesquisa
37.288225%
Many nutrients provide energy and regulate physiological processes linked to exercise. This work aimed at using medicinal plant in the manufacturing of energetic cookie. An evaluation of microbiological and physicochemical stability was made within 180 days of the fabrication of the product. Sensorial analysis was performed in all stages with untrained tasters. The results were statistically tested. The evaluation of ergogenic effect of the product used the maximum volume of oxygen index as a parameter through the cooper track test (12 minutes) with 7 voluntaries. The participants received the consent form. This study was approved by the local ethics committee (N° CAAE - 0009.0.313.000-08). It was observed good stability for physicochemical and microbiological parameters. As for sensorial analysis there was a predominance of scores 6 to 8, characterizing good acceptance. It was verified increase in VO2 max after the intake of the cookies with or without the medicinal plants. However, the product with the medicinal plants presented a bigger value, 35.47 VO2 max mL/(kg.min)-1. The fraction of carbohydrate and the presence of medicinal plants can be considered as nutritional ergogenic substances. The lipid fraction favor the energetic aspect of the product. The proposed product presented energetic and ergogenic effect.

Determination of myocardial energetic output for cardiac rhythm pacing

Heřman, Dalibor; Převorovská, Světlana; Maršík, František
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.09733%
This research is aimed to the determination of the changes in the cardiac energetic output for three different modes of cardiac rhythm pacing. The clinical investigation of thirteen patients with the permanent dual-chamber pacemaker implantation was carried out. The patients were taken to echocardiography examination conducted by way of three pacing modes (AAI, VVI and DDD). The myocardial energetic parameters—the stroke work index (SWI) and the myocardial oxygen consumption (MVO2) are not directly measurable, however, their values can be determined using the numerical model of the human cardiovascular system. The 24-segment hemodynamical model (pulsating type) of the human cardiovascular system was used for the numerical simulation of the changes of myocardial workload for cardiac rhythm pacing. The model was fitted by well-measurable parameters for each patient. The calculated parameters were compared using the two-tailed Student’s test. The differences of SWI and MVO2 between the modes AAI and VVI and the modes DDD and VVI are statistically significant (P < 0.05). On the other hand, the hemodynamic effects for the stimulation modes DDD and AAI are almost identical, i.e. the differences are statistically insignificant (P > 0.05).

Cancer Abolishes the Tissue Type-Specific Differences in the Phenotype of Energetic Metabolism1

Acebo, Paloma; Giner, Daniel; Calvo, Piedad; Blanco-Rivero, Amaya; Ortega, Álvaro D; Fernández, Pedro L; Roncador, Giovanna; Fernández-Malavé, Edgar; Chamorro, Margarita; Cuezva, José M
Fonte: Neoplasia Press Inc. Publicador: Neoplasia Press Inc.
Tipo: Artigo de Revista Científica
Publicado em 18/08/2009 Português
Relevância na Pesquisa
27.211133%
Nowadays, cellular bioenergetics has become a central issue of investigation in cancer biology. Recently, the metabolic activity of the cancer cell has been shown to correlate with a proteomic index that informs of the relative mitochondrial activity of the cell. Within this new field of investigation, we report herein the production and characterization of high-affinity monoclonal antibodies against proteins of the “bioenergetic signature” of the cell. The use of recombinant proteins and antibodies against the mitochondrial β-F1-ATPase and Hsp60 proteins and the enzymes of the glycolytic pathway glyceraldehyde-3-phosphate dehydrogenase and pyruvate kinase M2 in quantitative assays provide, for the first time, the actual amount of these proteins in normal and tumor surgical specimens of breast, lung, and esophagus. The application of this methodology affords a straightforward proteomic signature that quantifies the variable energetic demand of human tissues. Furthermore, the results show an unanticipated finding: tumors from different tissues and/or histological types have the same proteomic signature of energetic metabolism. Therefore, the results indicate that cancer abolishes the tissue-specific differences in the bioenergetic phenotype of mitochondria. Overall...

The Influence of Anthropometric, Kinematic and Energetic Variables and Gender on Swimming Performance in Youth Athletes

Morais, Jorge E; Garrido, Nuno D; Marques, Mário C; Silva, António J; Marinho, Daniel A; Barbosa, Tiago M
Fonte: Akademia Wychowania Fizycznego w Katowicach Publicador: Akademia Wychowania Fizycznego w Katowicach
Tipo: Artigo de Revista Científica
Publicado em 31/12/2013 Português
Relevância na Pesquisa
27.09733%
The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1–2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1–2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance...

El Niño-Southern Oscillation Is Linked to Decreased Energetic Condition in Long-Distance Migrants

Paxton, Kristina L.; Cohen, Emily B.; Paxton, Eben H.; Németh, Zoltán; Moore, Frank R.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 02/05/2014 Português
Relevância na Pesquisa
27.09733%
Predicting how migratory animals respond to changing climatic conditions requires knowledge of how climatic events affect each phase of the annual cycle and how those effects carry-over to subsequent phases. We utilized a 17-year migration dataset to examine how El Niño-Southern Oscillation climatic events in geographically different regions of the Western hemisphere carry-over to impact the stopover biology of several intercontinental migratory bird species. We found that migratory birds that over-wintered in South America experienced significantly drier environments during El Niño years, as reflected by reduced Normalized Difference Vegetation Index (NDVI) values, and arrived at stopover sites in reduced energetic condition during spring migration. During El Niño years migrants were also more likely to stopover immediately along the northern Gulf coast of the southeastern U.S. after crossing the Gulf of Mexico in small suboptimal forest patches where food resources are lower and migrant density often greater than larger more contiguous forests further inland. In contrast, NDVI values did not differ between El Niño and La Niña years in Caribbean-Central America, and we found no difference in energetic condition or use of coastal habitats for migrants en route from Caribbean-Central America wintering areas. Birds over-wintering in both regions had consistent median arrival dates along the northern Gulf coast...

Auditoria energética e da QAI no âmbito do SCE de um edifício de serviços

Morais, Luís Casimiro Afonso
Fonte: Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto Publicador: Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto
Tipo: Dissertação de Mestrado
Publicado em //2011 Português
Relevância na Pesquisa
27.144092%
Este trabalho foi realizado no âmbito da disciplina de Dissertação/Estágio do ramo de Optimização Energética na Indústria Química, do Mestrado em Engenharia Química do Instituto Superior de Engenharia do Porto e foi desenvolvido na empresa GreenWatt. O principal objectivo é efectuar uma auditoria energética e uma auditoria QAI a uma clínica de fisiatria de forma a preparar as ferramentas necessárias para a Certificação Energética e da QAI no enquadramento do Sistema de Certificação Energética. Na auditoria QAI foram analisados parâmetros físicos - temperatura, humidade relativa e partículas respiráveis PM10, parâmetros químicos - CO2, CO, O3, COVs, HCOH e o radão, e ainda parâmetros microbiológicos - bactérias, fungos e legionella. Na auditoria energética foi feita a caracterização dos vectores de energia utilizados no edifício, nomeadamente, gás natural e electricidade. Para esta caracterização efectuou-se um levantamento de toda a informação disponível relativa aos combustíveis utilizados, iluminação instalada, outros equipamentos consumidores de energia e perfis de utilização. Com recurso a analisadores de energia foram ainda medidos os consumos eléctricos do edifício. Com suporte nos dados provenientes da auditoria energética e das facturas anuais efectuou-se a validação da simulação dinâmica do edifício. Esta simulação é a base do cálculo do IEEnominal do edifício. Os resultados da auditoria QAI...

Energetic flux and performance index in copaiba (Copaifera multijuga Hayne) and mahogany (Swietenia macrophylla King) seedlings grown under two irradiance environments

Gonçalves,José F.C.; Santos Jr.,Ulysses M.; Nina Jr.,Adamir R.; Chevreuil,Larissa R.
Fonte: Brazilian Journal of Plant Physiology Publicador: Brazilian Journal of Plant Physiology
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2007 Português
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27.26546%
Plant adaptation under conditions of limited irradiance can be investigated by their efficiency while using the available energy with a minimal thermodynamic energy loss. For this reason, we compared the energetic fluxes and the performance index (PI ABS) in copaiba (Copaifera multijuga) and mahogany (Swietenia macrophyla) seedlings under both sunlight and shade. The experiment was carried out in Manaus (3º8'S, 59º52'W), Amazonas State, Brazil. The fluorescence transients were obtained in intact and healthy leaves using a Plant Efficiency Analyser (PEA) between 1200 h and 1300 h. Using the O-J-I-P test, the following parameters were calculated: 1) density of reaction centers per cross section (RC/CS), 2) maximum quantum yield for primary photochemistry of photosystem II (sigmaPo), and 3) probability of energy excitation (psio) or that of an absorbed photon (sigmaEo) to move an electron further than quinone A, and 4) the performance index (PI ABS). The highest PI ABS was found in seedlings under shade for both species. Mahogany seedlings exhibited values of PI ABS about three-fold and 14-fold higher than copaiba seedlings under shade and sunlight, respectively. For RC/CS, reaction centers were inactive under sunlight, 58% for mahogany and 78% for copaiba. The high irradiance induced a decrease of sigmaPo in mahogany (36%) and in copaiba (69%) when compared to shaded seedlings. This likely was a result of need for excess energy dissipation under sunlight. In addition...

An Interactive Program for Correlative Studies of Solar Energetic Particle Events

Al-Sawad, Amjad; Torsti, Jarmo; Hoffren, Hannu; Lehtomaki, Kari
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/07/2006 Português
Relevância na Pesquisa
27.211133%
We have developed an interactive program which shows the solar energetic particle (SEP) intensity-time profile as observed by SOHO/ERNE, simultaneously with the associated coronal mass ejection in optical imaging movies taken by LASCO coronagraph, soft X-ray by YOHKOH, ultraviolet by EIT, DH radio emission by WAVE/Wind, and the H$\alpha$ location for the solar flare and spectral radio emission from the journal of geophysical data. The whole set of data will provide increased scientific knowledge on the solar energetic particle events and the solar phenomena associated with them, because in this program one can see easily the temporal associations of each phenomenon during the evolution of the particle intensity. The (SEP) intensity-time profile will give a clear view to detect the velocity dispersion in the events, if it exists. The ERNE data are commented in order to follow of phenomena associated with changes of the intensity-time profiles. We introduce this set of data as an index for the ERNE/SOHO solar energetic particle events. The interactive program is applied for statistical, correlative study of SEP events observed on board SOHO.; Comment: Published in Proceedings of the 13th Young Scientists' Conference on Astronomy and Space Physics...

Synchrotron Cooling in Energetic Gamma-Ray Bursts Observed by the Fermi Gamma-Ray Burst Monitor

Yu, Hoi-Fung; Greiner, Jochen; van Eerten, Hendrik; Burgess, J. Michael; Bhat, P. Narayana; Briggs, Michael S.; Connaughton, Valerie; Diehl, Roland; Goldstein, Adam; Gruber, David; Jenke, Peter A.; von Kienlin, Andreas; Kouveliotou, Chryssa; Paciesas, Wil
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/10/2014 Português
Relevância na Pesquisa
27.340144%
We study the time-resolved spectra of eight GRBs observed by Fermi GBM in its first five years of mission, with 1 keV - 1 MeV fluence $f>1.0\times10^{-4}$ erg cm$^{-2}$ and signal-to-noise level $\text{S/N}\geq10.0$ above 900 keV. We aim to constrain in detail the spectral properties of GRB prompt emission on a time-resolved basis and to discuss the theoretical implications of the fitting results in the context of various prompt emission models. We perform time-resolved spectral analysis using a variable temporal binning technique according to optimal S/N criteria, resulting in a total of 299 time-resolved spectra. We fit the Band function to all spectra and obtain the distributions for the low-energy power-law index $\alpha$, the high-energy power-law index $\beta$, the peak energy in the observed $\nu F_\nu$ spectrum $E_\text{p}$, and the difference between the low- and high-energy power-law indices $\Delta s=\alpha-\beta$. Using the distributions of $\Delta s$ and $\beta$, the electron population index $p$ is found to be consistent with the "moderately fast" scenario which fast- and slow-cooling scenarios cannot be distinguished. We also apply a physically motivated synchrotron model, which is a triple power-law with constrained power-law indices and a blackbody component...

Waiting time distribution of solar energetic particle events modeled with a non-stationary Poisson process

Li, Chuan; Zhong, Sijia; Wang, Linghua; Su, Wei; Fang, Cheng
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/08/2014 Português
Relevância na Pesquisa
27.329026%
We present a study of the waiting time distributions (WTDs) of solar energetic particle (SEP) events observed with the spacecraft $WIND$ and $GOES$. Both the WTDs of solar electron events (SEEs) and solar proton events (SPEs) display a power-law tail $\sim \Delta t^{-\gamma}$. The SEEs display a broken power-law WTD. The power-law index is $\gamma_{1} =$ 0.99 for the short waiting times ($<$70 hours) and $\gamma_{2} =$ 1.92 for large waiting times ($>$100 hours). The break of the WTD of SEEs is probably due to the modulation of the corotating interaction regions (CIRs). The power-law index $\gamma \sim$ 1.82 is derived for the WTD of SPEs that is consistent with the WTD of type II radio bursts, indicating a close relationship between the shock wave and the production of energetic protons. The WTDs of SEP events can be modeled with a non-stationary Poisson process which was proposed to understand the waiting time statistics of solar flares (Wheatland 2000; Aschwanden $\&$ McTiernan 2010). We generalize the method and find that, if the SEP event rate $\lambda = 1/\Delta t$ varies as the time distribution of event rate $f(\lambda) = A \lambda^{-\alpha}exp(-\beta \lambda)$, the time-dependent Poisson distribution can produce a power-law tail WTD $\sim \Delta t^{\alpha - 3}$...

Parameter estimation of superdiffusive motion of energetic particles upstream of heliospheric shocks

Perri, Silvia; Zimbardo, Gaetano; Effenberger, Frederic; Fichtner, Horst
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/05/2015 Português
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In-situ spacecraft observations recently suggested that the transport of energetic particles accelerated at heliospheric shocks can be anomalous, i.e. the mean square displacement can grow non-linearly in time. In particular, a new analysis technique has permitted the study of particle transport properties from energetic particle time profiles upstream of interplanetary shocks. Indeed, the time/spatial power laws of the differential intensity upstream of several shocks are indicative of superdiffusion. A complete determination of the key parameters of superdiffusive transport comprises the power-law index, the superdiffusion coefficient, the related transition scale at which the energetic particle profiles turn to decay as power laws, and the energy spectral index of the shock accelerated particles. Assuming large-scale spatial homogeneity of the background plasma, the power-law behaviour can been derived from both a (microscopic) propagator formalism and a (macroscopic) fractional transport equation. We compare the two approaches and find a relation between the diffusion coefficients used in the two formalisms. Based on the assumption of superdiffusive transport, we quantitatively derive these parameters by studying energetic particle profiles observed by the Ulysses and Voyager 2 spacecraft upstream of shocks in the heliosphere...