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Search Results: 1 - 10 of 621796 matches for " Antonio L. A. Fonseca "
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Quantization and Stable Attractors in a DissipativeOrbital Motion  [PDF]
Daniel L. Nascimento, Antonio L. A. Fonseca
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24030
Abstract: We present a method for determining the motion of an electron in a hydrogen atom, which starts from a field Lagrangean foundation for non-conservative systems that can exhibit chaotic behavior. As a consequence, the problem of the formation of the atom becomes the problem of finding the possible stable orbital attractors and the associated transition paths through which the electron mechanical energy varies continuously until a stable energy state is reached.
A Variational Approach for Numerically Solving the Two-Component Radial Dirac Equation for One-Particle Systems  [PDF]
Antonio L. A. Fonseca, Daniel L. Nascimento, Fabio F. Monteiro, Marco A. Amato
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.34048
Abstract: In this paper we propose a numerical approach to solve the relativistic Dirac equation suitable for computational calculations of one-electron systems. A variational procedure is carried out similar to the well-known Hylleraas computational method. An application of the method to hydrogen isoelectronic atoms is presented, showing its consistency and high accuracy, relative to the exact analytical eigenvalues.
Proposta de método de inspe??o de radioprote??o aplicada em instala??es de medicina nuclear
Mendes, Leopoldino da Cruz Gouveia;Fonseca, Léa Mirian Barbosa da;Carvalho, Antonio Carlos Pires;
Radiologia Brasileira , 2004, DOI: 10.1590/S0100-39842004000200009
Abstract: the main objective of this study is to implement an impartial and efficient inspection method for a correct and secure use of ionizing radiation in nuclear medicine. the radiological protection model was tested in 113 nuclear medicine services (nms) all over brazil, following a biannual analysis schedule (1996, 1998, 2000 and 2002). in the analytical process, we adopted the methodology of assigning different importance levels to each of 82 features, based on the risk factors established by the "comiss?o nacional de energia nuclear" (cnen) and on the international atomic energy agency (iaea) recommendations. a feature was considered a radioprotection fault when in nonconformity with the rules mentioned above, and was imparted a grade. the sum of those grades, classified the nms in one of the three different ranges, as follows: operating without restriction - 100 points and below; operating with restriction - between 100 and 300 points; temporary shutdown - above 300 points. permission for the second group to carry on operation should be attached to a defined and restricted period of time (6 to 12 months), considered enough for the nms to solve the problems and submit to a new evaluation. the nms's classified in the third group are supposed to go back into operation only after compliance with all the pending radioprotection requirements. until the next regular evaluation, a multiplication factor 2n was applied to the recalcitrant nms's, where n is the number of unwilling occurrences. the previous establishment of those items of radioprotection, with their respective grades, excluded subjective and personal values in the judgement and technical evaluation of the institutions.
Proposta de método de inspe o de radioprote o aplicada em instala es de medicina nuclear
Mendes Leopoldino da Cruz Gouveia,Fonseca Léa Mirian Barbosa da,Carvalho Antonio Carlos Pires
Radiologia Brasileira , 2004,
Abstract: O objetivo principal deste trabalho é implantar um método de inspe o imparcial e eficiente, visando à utiliza o segura e correta das radia es ionizantes no campo da medicina nuclear. Este método de inspe o aqui proposto foi aplicado em 113 servi os de medicina nuclear do país, obedecendo a uma freqüência de análise bienal (1996, 1998, 2000 e 2002). Foram estabelecidos 82 itens de radioprote o com pesos para cada item, baseados nos fatores de risco, de acordo com as normas da Comiss o Nacional de Energia Nuclear (CNEN) e as recomenda es da Agência Internacional de Energia At mica. Na análise do servi o, cada item de n o conformidade com as normas da CNEN gerou uma irregularidade de radioprote o, com seu peso associado. O somatório dos pesos deu a cada servi o uma pontua o final que o classificou dentro de três faixas de valores que determinaram uma tomada de decis o por parte do órg o regulador e fiscalizador: funcionamento sem restri o - menor que 100 pontos; funcionamento com restri o - igual ou maior que 100 e menor que 300 pontos; funcionamento suspenso - igual ou maior que 300 pontos. Para o caso de irregularidades reincidentes, criou-se um fator multiplicativo para a pontua o. A reincidência em qualquer item de radioprote o (irregularidade) teve seu peso multiplicado por 2n, onde n era o número de vezes em que o item encontrava-se irregular. O estabelecimento prévio de itens de radioprote o, com atribui o de pesos para cada item, procurou minimizar os valores subjetivos e pessoais presentes no julgamento e na avalia o técnica das institui es inspecionadas.
Physicochemical characteristics and sensory profile of honey samples from stingless bees (Apidae: Meliponinae) submitted to a dehumidification process
Carvalho, Carlos A.L.;Sodré, Geni S.;Fonseca, Antonio A.O.;Alves, Rogério M.O.;Souza, Bruno A.;Clarton, Lana;
Anais da Academia Brasileira de Ciências , 2009, DOI: 10.1590/S0001-37652009000100015
Abstract: this study was conducted to evaluate the effect of a dehumidification process on the physicochemical and sensory characteristics of stingless-bee honey. melipona scutellaris and m. quadrifasciata honey samples were submitted to a dehumidification process and to physicochemical (reducing sugars, apparent sucrose, moisture, diastatic activity, hydroxymethylfurfural, ash, ph, acidity, and electric conductivity) and sensory evaluations (fluidity, color, aroma, crystallization,flavor,and acceptability). the results indicated that the dehumidification process does not interfere with honey quality and acceptability.
Perfil lipídico e efeitos da orienta??o nutricional em adolescentes com história familiar de doen?a arterial coronariana prematura
Mendes, Gislaine A.;Martinez, Tania L.;Izar, Maria C.;Amancio, Olga M.;Novo, Neil F.;Matheus, Simone C.;Bertolami, Marcelo C.;Fonseca, Francisco Antonio Helfenstein;
Arquivos Brasileiros de Cardiologia , 2006, DOI: 10.1590/S0066-782X2006000500006
Abstract: objective: to assess lipid profile and nutritional parameters from adolescents with family history of premature coronary artery disease (cad) and assess the effects of nutritional counseling. methods: the study included 48 adolescents of both gender and with ages ranging from 10 and 19 years old (case group, n=18; control group, n=30). results: offspring of young individuals with coronary artery disease showed higher values of total cholesterol (189 ± 30 vs. 167 ± 26 mg/dl, p < 0.01), ldl-c (144 ± 20 vs. 100 ± 27 mg/dl, p < 0.001) and apob (80 ± 15 vs. 61 ± 18 mg/dl, p = 0.001) and lower values of hdl-c (45 ± 9 vs. 51 ± 13 mg/dl, p < 0.02) than control young individuals. differences were not found for triglycerides and apoa-i. with a dietotherapeutic counseling, we obtained a reduction in alimentary consumption of saturated fatty acids (pre: 15.5 ± 4.7% vs. post: 6.6 ± 3.7%, p = 0.003) and an improvement in lipid profile: tc (-8%, p = 0.033), ldl-c (-18.2%, p = 0.001), tg (-53%, p = 0.002) rates in offspring of premature cad patients who showed hyperlipidemia. conclusion: the presence of dyslipidemia was more prevalent among offspring adolescents of premature cad patients, but it was responsive to nutritional intervention.
Análise dosimétrica de acompanhantes de pacientes de medicina nuclear internados em quarto terapêutico
Oliveira, Jetro Pereira de;Lopes, Márcia Maria dos Santos;Rosa, Luiz Antonio Ribeiro da;Fonseca, Léa Mirian Barbosa da;Corbo, Rossana;
Radiologia Brasileira , 2008, DOI: 10.1590/S0100-39842008000100010
Abstract: objective: the present study evaluated the doses received by companions who had shared therapeutic rooms with patients undergoing treatment with 131-iodine (131i). the results were compared with the limits established by the brazilian radiation protection regulatory standard. materials and methods: six pairs of persons (a patient and a companion sharing a same therapeutic room) were evaluated. still, other 23 experiments were accomplished with a phantom replacing the companion. the therapeutic 131i activities given to the patients corresponded to 3700 mbq or 5550 mbq. powdered lithium fluoride thermoluminescent dosimeters doped with magnesium, titanium and sodium were utilized for evaluating the doses. results: the results demonstrate that a person sharing a same therapeutic room, for two days, with a patient who had been given 3700 mbq or 5550 mbq of 131i, according to radioprotection recommendations, is exposed to a mean dose of (0.51 ± 0.02) msv for a 99% confidence level. conclusion: according to the brazilian radiation protection standards there is no impediment for a person to accompany a nuclear medicine patient who has been given 3700 mbq or 5550 mbq of 131i during the patient stay in the therapeutic room.
Allelopathic potential of extracts the from marine macroalga Plocamium brasiliense and their effects on pasture weed
Fonseca, Rainiomar Raimundo da;Ortiz-Ramírez, Fredy A.;Cavalcanti, Diana N.;Ramos, Carlos José B.;Teixeira, Valéria L.;Sousa Filho, Antonio Pedro da Silva;
Revista Brasileira de Farmacognosia , 2012, DOI: 10.1590/S0102-695X2012005000065
Abstract: four extracts from the marine red alga plocamium brasiliense (greville) m.a.howe & w.r.taylor were prepared to identify and characterize their potential allelopathic effects on seed germination, radicle elongation and hypocotyl development of the weeds mimosa pudica l. and senna obtusifolia (l.) irwin & barneby. the four extracts were prepared in a sequence of solvents of increasing polarity: n-hexane, dichloromethane, ethyl acetate and ethanol/water (7:3). the germination bioassay was carried out at 25 °c with a 12 h photoperiod and the radicle elongation and hypocotyl development at 25 °c with a 24 h photoperiod. the dichloromethane extract showed inhibitory effects on seed germination of both plants (35 and 14%, respectively, in m. pudica and s. obtusifolia), radical germination (52 and 41.7%, respectively) and hypocotyl development (17.1 and 25.5%, respectively). given the high sensitivity of this parameter to the potential allelopathic effects and the insufficient number of references found in the literature, these results are expected to stimulate new tests with other species of marine algae. given the high sensitivity of the method for the detection of allelopathic potential, the species p. brasiliense emerges as a possible source of allelopathic substances against weed species. the results are attributed to the chemical composition, especially in relation to the presence of halogenated monoterpenes.
Avalia??o de transplantes renais utilizando-se 99mTc-leucócitos mononucleares
Souza, Sergio Augusto Lopes de;Martins, Flávia Paiva Proen?a;Gon?alves, Renato Torres;Pontes, Daniela Salom?o;Carvalho, Antonio Carlos Pires;Fonseca, Léa Mirian Barbosa da;Gutfilen, Bianca;
Radiologia Brasileira , 2004, DOI: 10.1590/S0100-39842004000100005
Abstract: renal allograft acute rejection must be promptly diagnosed since its reversibility is related to the readiness in which treatment is initiated. the aim of this study was: 1) to establish a quantitative method to evaluate kidney rejection and acute tubular necrosis (atn); 2) to assess the potential role of 99mtc-mononuclear leukocytes scintigraphy in the diagnosis of renal rejection and differential diagnosis of atn. one hundred and sixty studies were performed in 80 renal transplant patients at the first and fifth day after transplantation. autologous cells were used for labeling. images were obtained at 30 minutes, 3 hours and 24 hours after intravenous administration of 444 mbq (12 mci) of labeled cells. there was abnormal labeled cells uptake in 27 of 31 cases of rejection and in 6 of 8 cases of atn. the results of each patient were compared with clinical findings. doppler scanning detected 18 of 31 cases of rejection. rejection diagnosis sensitivity and specificity rates using scintigraphy were 87.1% and 100%, respectively, and 58.1% and 100%, respectively using ultrasound. renal biopsy was performed in eight patients which demonstrated seven cases of rejection and one case of atn. these results suggest that 99mtc-mononuclear leukocytes imaging may be useful in the early diagnosis of rejection and in the differential diagnosis of atn.
Genes do eixo somatotrófico e características de crescimento numa popula??o F2 de bovinos
Silva, Marcos Vinicius Gualberto Barbosa da;Martinez, Mário Luiz;Machado, Marco Antonio;Nascimento, Carlos Souza do;Campos, Ana Lúcia;Guimar?es, Marta Fonseca Martins;Azevedo, Ana Luisa Sousa;Moita, Ant?nia Kécya Fran?a;Lui, Jeffrey Frederico;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000600013
Abstract: the objective of this work was to evaluate the association between polymorphisms of bgh, igf-1 and pit-1 genes with weight and weight gain traits in a bovine f2 population derived from holstein x gyr crosses, using the pcr-rflp technique. allelic frequencies a and b of pit-1 gene and aa, ab, and bb genotypes were similar between parental populations but different from f1 and f2 crossed populations. for the bgh gene, holstein animals showed allelic frequency of 100% for e allele, while gyr animals showed allelic frequency of 92% for f allele, resulting in high frequency of heterozygous animals in f1 and f2 populations. for the igf-1 gene, all holstein were heterozygous (ab) and most gyr were homozygous (aa), resulting in a high frequency of a allele in f1 and f2 populations. significant associations were found between pit-1 allele a with traits weight at 60, 205 and 365 days and weight gain from birth to 60 days. for igf-1, significant association was found between a allele and birth weight. for bgh gene, significant associations were found between e allele and 365 days weight and weight gain from birth to 60 days. the selected alleles could be used as markers in animal breeding for these traits.
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