3,341 research outputs found
Fatores de Risco e o Spread Bancário no Brasil
This work analyzes the determinants of the banking interest rate margin in Brazil from 2001 to 2004. Based on the Ho and Saunders' (1981) theoretical model, we verify the impacts of risk factors - interest-rate risk and default risk - and administrative costs over the banking interest rate margin charged. We used panel data to the bank-level variables and we applied the methodology proposed by Chamberlain (1982) for models with non-observed individual characteristics. The main conclusions are: (i) default risk, interest-rate risk and administrative costs have positive effects over the interest rate margin; (ii) beside this factors, there are other characteristics that have a significant impact over the interest rate margin, e.g. the liquidity level of the bank, the market-share and the banking services revenues; and (iii) the Chamberlain's methodology shows considerable efficiency gains relative to the 'fixed-effects' estimation in this sample.
Risk Management in Scrum Projects: A Bibliometric Study
This article presents a bibliometric study of Risk Management in Scrum Projects. It was carried out an analysis involving the ISI Web of Knowledge and Scopus databases, identifying the main authors, countries and periodicals. It also identified the most cited authors by the analyzed articles, in addition to the keywords most frequently cited. These analyzes were performed using the reference maps, which were generated by CiteSpace® software, which offers a set of features to support bibliometrics. The objective was to identify the current scenario research of Risk Management applied in Scrum Projects in order to offer a consistent basis of information to researchers. The research verified that, despite the importance of the research topic, few scientific studies have been identified, which brings the need for new researches on the subject
Selection Rules for One- and Two-Photon Absorption by Excitons in Carbon Nanotubes
Recent optical absorption/emission experiments showed that the lower energy
optical transitions in carbon nanotubes are excitonic in nature, as predicted
by theory. These experiments were based on the symmetry aspects of free
electron-hole states and bound excitonic states. The present work shows,
however, that group theory does not predict the selection rules needed to
explain the two photon experiments. We obtain the symmetries and selection
rules for the optical transitions of excitons in single-wall carbon nanotubes
within the approach of the group of the wavevector, thus providing important
information for the interpretation of theoretical and experimental optical
spectra of these materials.Comment: 4 pages, 1 figure, 1 tabl
Fermi-Energy-Dependent Structural Deformation of Chiral Single-Wall Carbon Nanotubes
In this work, we use an extended tight-binding approach for calculating the Fermi-energy dependence of the structural deformation of chiral single-wall carbon nanotubes (SWNTs). We show that, in general, nanotube strains occur in such a way as to avoid a net charge from being accumulated on the nanotube. We also investigate the effect of the Fermi-energy-induced strains on the electronic structure of SWNTs, showing that the optical transition energies change by up to 0.5 eV due to the induced strains and that this change is nearly independent of how the nanotube is deformed. Finally, we also consider the contribution of the electron-electron Coulomb repulsion to the total energy by using an effective regularized potential energy model. We show that the inclusion of the Coulomb repulsion leads to larger strains and smaller net charges transferred to the nanotube.National Science Foundation (U.S.) (Grant DMR-1004147
Availability of pediatric and neonatal intensive care units in the city of São Paulo
OBJECTIVE: To describe the health care service provided in pediatric intensive care units in the city of São Paulo, by identifying and describing the units and analyzing their geographic distribution. METHODS: A descriptive cross-sectional study was carried out during a two-year period (August 2000 to July 2002). Data were collected through questionnaires answered by medical directors of each pediatric and neonatal intensive care unit. RESULTS: São Paulo is served by 107 pediatric and neonatal intensive care units, of which 85 (79.4%) completed and returned the questionnaire. We found a very unequal distribution of units as there were more units in places with the least pediatric population. Regarding to pediatric intensive care units specialization, 7% were pediatric, 41.2% were neonatal and 51.7% were mixed (pediatric and neonatal). Regarding hospital funds, 15.3% were associated with philanthropic institutions, 37.6% were private and 47% were public. A total of 1,067 beds were identified, of which 969 were active. The ratio bed/patient aged 0-14 was 1/2,728, varying from 1/604 at health districts - I to 1/6,812 at health districts - III. The units reported an average of 11.7 beds (2 to 60). The neonatal intensive care unit had a median of 16.9 beds per unit and pediatric intensive care units a median of 8.5 beds/unit. CONCLUSION: In São Paulo, we found an uneven distribution of pediatric and neonatal intensive care units among the health districts. There was also an uneven distribution between public and private units, and neonatal and pediatric ones. The current report is the first step in the effort to improve the quality of medical assistance in pediatric and neonatal intensive care units in São Paulo.OBJETIVO: Caracterizar a assistência de saúde prestada em tratamento intensivo pediátrico e neonatal no município de São Paulo através da identificação, descrição e distribuição geográfica das unidades. MÉTODOS: Estudo descritivo, tipo transversal, onde foram estudadas as unidades de terapia intensiva pediátrica e neonatal do município de São Paulo, no período de agosto de 2000 a julho de 2002. A coleta dos dados foi realizada por meio de questionário preenchido pelo coordenador médico de cada unidade. RESULTADOS: Foram listadas 107 unidades de terapia intensiva pediátricas e neonatais no município de São Paulo. Oitenta e cinco (79,4%) unidades forneceram os dados, constituindo a população de estudo. Observou-se maior número de unidades de terapia intensiva em Núcleos Regionais de Saúde com menor população pediátrica. Quanto à faixa etária, 7% eram exclusivamente pediátricas, 41,2% neonatais, e 51,7% mistas. Em relação ao mantenedor: 47% eram públicas, 37,6% privadas, e 15,3% filantrópicas. Identificamos 1.067 leitos, estando 969 em atividade. A razão leito/paciente de 0 a 14 anos foi de 1:2.728, variando de 1:604 (Núcleo Regional de Saúde - I) a 1:6.812 (Núcleo Regional de Saúde - III). O número de leitos por unidade variou de 2 a 60, com média de 11,7 (unidades de terapia intensiva neonatais: 16,9; mistas: 8,5). CONCLUSÃO: No município de São Paulo, observou-se uma distribuição desproporcional das unidades de terapia intensiva pediátrica e neonatal entre os cinco Núcleos Regionais de Saúde. Houve também uma distribuição desproporcional entre unidades de terapia intensiva públicas e privadas e entre neonatais e pediátricas. Esse estudo foi o primeiro esforço na busca por melhor qualidade na assistência intensiva pediátrica e neonatal no município de São Paulo.Universidade de São Paulo Faculdade de MedicinaUniversidade Federal de São Paulo (UNIFESP) Departamento de PediatriaUniversidade de São Paulo Hospital Universitário Unidade de Terapia Intensiva PediátricaUNIFESP, Depto. de PediatriaSciEL
A Novel Stress-induced Sugarcane Gene Confers Tolerance To Drought, Salt And Oxidative Stress In Transgenic Tobacco Plants.
Drought is a major abiotic stress that affects crop productivity worldwide. Sugarcane can withstand periods of water scarcity during the final stage of culm maturation, during which sucrose accumulation occurs. Meanwhile, prolonged periods of drought can cause severe plant losses. In a previous study, we evaluated the transcriptome of drought-stressed plants to better understand sugarcane responses to drought. Among the up-regulated genes was Scdr1 (sugarcane drought-responsive 1). The aim of the research reported here was to characterize this gene. Scdr1 encodes a putative protein containing 248 amino acids with a large number of proline (19%) and cysteine (13%) residues. Phylogenetic analysis showed that ScDR1is in a clade with homologs from other monocotyledonous plants, separate from those of dicotyledonous plants. The expression of Scdr1 in different varieties of sugarcane plants has not shown a clear association with drought tolerance. The overexpression of Scdr1 in transgenic tobacco plants increased their tolerance to drought, salinity and oxidative stress, as demonstrated by increased photosynthesis, water content, biomass, germination rate, chlorophyll content and reduced accumulation of ROS. Physiological parameters, such as transpiration rate (E), net photosynthesis (A), stomatal conductance (gs) and internal leaf CO(2) concentration, were less affected by abiotic stresses in transgenic Scdr1 plants compared with wild-type plants. Overall, our results indicated that Scdr1 conferred tolerance to multiple abiotic stresses, highlighting the potential of this gene for biotechnological applications.7e4469
Risk Management in Scrum Projects: A Bibliometric Study
This article presents a bibliometric study of Risk Management in Scrum Projects. It was carried out an analysis involving the ISI Web of Knowledge and Scopus databases, identifying the main authors, countries and periodicals. It also identified the most cited authors by the analyzed articles, in addition to the keywords most frequently cited. These analyzes were performed using the reference maps, which were generated by CiteSpace® software, which offers a set of features to support bibliometrics. The objective was to identify the current scenario research of Risk Management applied in Scrum Projects in order to offer a consistent basis of information to researchers. The research verified that, despite the importance of the research topic, few scientific studies have been identified, which brings the need for new researches on the subject
The Analyticity of a Generalized Ruelle's Operator
In this work we propose a generalization of the concept of Ruelle operator
for one dimensional lattices used in thermodynamic formalism and ergodic
optimization, which we call generalized Ruelle operator, that generalizes both
the Ruelle operator proposed in [BCLMS] and the Perron Frobenius operator
defined in [Bowen]. We suppose the alphabet is given by a compact metric space,
and consider a general a-priori measure to define the operator. We also
consider the case where the set of symbols that can follow a given symbol of
the alphabet depends on such symbol, which is an extension of the original
concept of transition matrices from the theory of subshifts of finite type. We
prove the analyticity of the Ruelle operator and present some examples
Microbiota no trato digestivo em voluntários saudáveis
PURPOSE: The aim of this study was to standardize the methods of sample collection of mucus from the digestive tract and to determine the microbiota in healthy volunteers from Brazil, collecting samples from the mouth, esophagus, stomach, duodenum, jejunum, ileum, colon, and rectum. METHODS: Microbiota of selected healthy volunteers from the oral cavity (n=10), the esophagus (n=10), the upper digestive tract (n=20), and the lower digestive tract (n=24) were evaluated through distinct collection methods. Collection methods took into account the different sites, using basic scraping and swabbing techniques, stimulated saliva from the oral cavity, irrigation-aspiration with sterile catheters especially designed for the esophagus, a probe especially designed for upper digestive tract, and a special catheter for the lower digestive tract. RESULTS: (i) Mixed microbiota were identified in the oral cavity, predominantly Gram-positive aerobic and anaerobic cocci; (ii) transitional flora mainly in the esophagus; (iii) Veillonella sp, Lactobacillus sp, and Clostridium sp in the stomach and duodenum; (iv) in the jejunum and upper ileum, we observed Bacteroides sp, Proteus sp, and Staphylococcus sp, in addition to Veillonella sp; (v) in the colon, the presence of "nonpathogenic" anaerobic bacteria Veillonella sp (average 10(5) UFC) indicates the existence of a low oxidation-reduction potential environment, which suggests the possibility of adoption of these bacteria as biological markers of total digestive tract health. CONCLUSIONS: The collection methods were efficient in obtaining adequate samples from each segment of the total digestive tract to reveal the normal microbiota. These procedures are safe and easily reproducible for microbiological studies.OBJETIVO: Padronizar os métodos de coleta do muco do trato digestivo e determinar a microbiota, em voluntários saudáveis no Brasil, coletando amostras da boca, esôfago, estômago, duodeno, jejunos e íleo, cólons e reto. MÉTODOS: A microbiota de voluntários saudáveis foi avaliada através de diferentes métodos de coleta: cavidade oral (n=10 voluntários), do esôfago (n=10), do trato digestivo alto (n=20) e do trato digestivo baixo (n=24). Métodos de coleta foram adotados em cada sítio restrito, usando derramar saliva, técnica de esfregar a mucosa e saliva estimulada da cavidade oral, irrigação-aspiração, cateteres específicos designados para o esôfago, sonda especial para o trato digestivo alto e cateteres especiais para o trato digestivo baixo. RESULTADOS: Identificados: (i) na cavidade oral, microbiota mista, predominando cocos aeróbios e anaeróbios Gram positivos; (ii) no esôfago, flora transitória; (iii) no estômago e duodeno, Veillonella sp, Lactobacillus sp and Clostridium sp; (iv) no jejuno e íleo proximal, Bacteróides sp, Proteus sp and Staphilococcus sp, além da Veillonella sp ; (v) no colon, foi revelada a presença "não patogênica" da bactéria anaeróbica Veillonella sp numa concentração média de 10(5) unidades formadoras de colônia, indicando um meio de baixo potencial de oxido-redução e a possibilidade de se conceituar esta bactéria como um marcador biológico do trato digestivo total em sadios. CONCLUSÃO: Estes métodos de coleta foram considerados eficientes para obtenção adequada de amostra em cada segmento do trato digestivo total para caracterizar a microbiota normal. Estes procedimentos são seguros e facilmente reprodutível para estudo microbiológico
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