4,038 research outputs found

    A diversificação das receitas bancárias: seu impacto sobre o risco e o retorno dos bancos brasileiros

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    O objetivo deste estudo é determinar o impacto da diversificação das receitas bancárias sobre o risco e o retorno dos bancos brasileiros. Essa estratégia foi adotada por bancos em diversos países, inclusive no Brasil. Em 2003, as receitas noninterest (não decorrentes de juros) representavam 17,80% da receita operacional dos bancos analisados e, em 2014, essa participação havia aumentado para 27,40%. Embora muitos estudos tenham abordado a questão para bancos americanos, europeus e asiáticos, este tema ainda não foi abordado para uma amostra de bancos brasileiros. Como o setor bancário é uma variável crucial à estabilidade do sistema financeiro, é importante estudar os fatores que afetam o risco e o retorno dos bancos. Analisamos a amostra para o período entre 2003 e 2014, utilizando dados em painel dinâmico através do Método Generalizado dos Momentos para abordar questões de endogeneidade, heterocedasticidade e autocorrelação. Nossos principais resultados mostram que as receitas noninterest possuem um papel importante no desempenho dos bancos estudados; nossa análise das atividades de intermediação financeira mostrou que as operações de crédito produziram melhores resultados do que as atividades de negociação de títulos. Além disso, confirmando as hipóteses propostas, as receitas noninterest apresentaram, de maneira geral, um impacto positivo sobre o retorno e o retorno ajustado ao risco nos bancos estudados. Entretanto, ao contrário do que esperávamos, as receitas noninterest mostraram uma relação positiva com o risco desses bancos (embora estatisticamente não significativa). É importante destacar as variáveis de controle, ou seja, a taxa de juros real, o PIB e o crescimento bancário, as quais foram relevantes para a determinação do desempenho dos bancos.The present study aims to determine the impact of bank revenue diversification on Brazilian banks’ risk and return. This strategy has been adopted by banks in several countries, including Brazil. In 2003, noninterest income accounted for 17.80% of the operating revenue of the banks analyzed, and in 2014, this share increased to 27.40%. While many studies have addressed the subject in American, European and Asian banks, it still has not been approached in a sample of Brazilian banks. Since the banking industry is a key variable for the financial system’s stability, it is important to study the factors that affect banks’ risk and return. We analyzed the sample for the period from 2003 to 2014, using dynamic panel data GMM (Generalized Method of Moments) to address endogeneity, heteroscedasticity and autocorrelation problems. Our main results show that noninterest income has a major role in the performance of the banks studied; our analysis of financial intermediation activities showed that loan operations produced better results than trading. Moreover, confirming the hypotheses proposed, noninterest income showed a generally positive impact on return and risk adjusted return for the banks studied. However, against our expectation, noninterest income showed a positive relationship with the risk of these banks (although not statistically significant). It is worth highlighting the control variables, i.e., real interest rate, GDP and bank growth, which were relevant in determining bank performance

    A Case Study in Macao

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    Funding Information: This research was funded by Fundação para a Ciência e Tecnologia, I.P., Portugal, grant number UID/AMB/04085/2020, and the APC was funded by CENSE. Funding Information: The work developed was supported by The Macao Meteorological and Geophysical Bureau (SMG). Publisher Copyright: © 2022 by the authors.Despite the levels of air pollution in Macao continuing to improve over recent years, there are still days with high-pollution episodes that cause great health concerns to the local community. Therefore, it is very important to accurately forecast air quality in Macao. Machine learning methods such as random forest (RF), gradient boosting (GB), support vector regression (SVR), and multiple linear regression (MLR) were applied to predict the levels of particulate matter (PM10 and PM2.5) concentrations in Macao. The forecast models were built and trained using the meteorological and air quality data from 2013 to 2018, and the air quality data from 2019 to 2021 were used for validation. Our results show that there is no significant difference between the performance of the four methods in predicting the air quality data for 2019 (before the COVID-19 pandemic) and 2021 (the new normal period). However, RF performed significantly better than the other methods for 2020 (amid the pandemic) with a higher coefficient of determination (R2) and lower RMSE, MAE, and BIAS. The reduced performance of the statistical MLR and other ML models was presumably due to the unprecedented low levels of PM10 and PM2.5 concentrations in 2020. Therefore, this study suggests that RF is the most reliable prediction method for pollutant concentrations, especially in the event of drastic air quality changes due to unexpected circumstances, such as a lockdown caused by a widespread infectious disease.publishersversionpublishe

    A 1.8 million year history of Amazon vegetation

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    During the Pleistocene, long-term trends in global climate were controlled by orbital cycles leading to high amplitude glacial-interglacial variability. The history of Amazonian vegetation during this period is largely unknown since no continuous record from the lowland basin extends significantly beyond the last glacial stage. Here we present a paleoenvironmental record spanning the last 1800 kyr based on palynological data, biome reconstructions, and biodiversity metrics from a marine sediment core that preserves a continuous archive of sediments from the Amazon River. Tropical rainforests dominated the Amazonian lowlands during the last 1800 ka interchanging with surrounding warm-temperate rainforests and tropical seasonal forests. Between 1800 and 1000 ka, rainforest biomes were present in the Amazon drainage basin, along with extensive riparian wetland vegetation. Tropical rainforest expansion occurred during the relatively warm Marine Isotope Stages 33 and 31 (ca. 1110 to 1060 ka), followed by a contraction of both forests and wetlands until ca. 800 ka. Between 800 and 400 ka, low pollen concentration and low diversity of palynological assemblages renders difficult the interpretation of Amazonian vegetation. A strong synchronicity between vegetation changes and glacial-interglacial global climate cycles was established around 400 ka. After 400 ka, interglacial vegetation was dominated by lowland tropical rainforest in association with warmer temperatures and higher CO2. During cooler temperatures and lower CO2 of glacial stages, tropical seasonal forests expanded, presumably towards eastern Amazonia. While this study provides no evidence supporting a significant expansion of savanna or steppe vegetation within the Amazonian lowlands during glacial periods, there were changes in the rainforest composition in some parts of the basin towards a higher proportion of deciduous elements, pointing to less humid conditions and/or greater seasonality of precipitation. Nevertheless, rainforest persisted during both glacial and interglacial periods. These findings confirm the sensitivity of tropical lowland vegetation to changes in CO2, temperature, and moisture availability and the most suitable conditions for tropical rainforests occurred during the warmest stages of the Mid Pleistocene Transition and during the interglacial stages of the past 400 kyr

    Antioxidant capacity and toxicological evaluation of pterospartum tridentatum flower extracts

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    Pterospartum tridentatum Willk. (prickled broom) is an autochthonous plant, common in Portuguese territory. The yellow flowers are used in traditional medicine, as a potential cure for all body illnesses, mainly for throat irritation treatment or for diabetes, hypertension and hypercholesterolemia therapy.Despite its traditional use, no toxicological assessment has been performed as we know. A high antioxidant activity of P. tridentatum flower water extract was acessed in good agreement with its ESI-MS spectrum that revealed the presence of several flavonoids, as luteolin-O-(O-acetyl)-glucuronide, luteolin-O- glucuronide or isorhamnetin-O-hexoside. Mitocondrial respiratory rates (state 4, state 3 and FCCP-stimulated respiration) and respiratory indexes (respiratory control and P/O ratios) showed no consistent decrease of respiratory and phosphorylative efficiencies for the concentrations tested (up to 500 μg.mL-1). Cytotoxicity evaluation, using MTT assay, was reliable with the previous results. In conclusion, for the concentration range commonly used P. tridentatum flowers usage can be regarded as harmless and trustworthy

    Modulation of hypothalamic AMPK phosphorylation by olanzapine controls energy balance and body weight

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    [Background]: Second-generation antipsychotics (SGAs) are a mainstay therapy for schizophrenia. SGA-treated patients present higher risk for weight gain, dyslipidemia and hyperglycemia. Herein, we evaluated the effects of olanzapine (OLA), widely prescribed SGA, in mice focusing on changes in body weight and energy balance. We further explored OLA effects in protein tyrosine phosphatase-1B deficient (PTP1B-KO) mice, a preclinical model of leptin hypersensitivity protected against obesity.[Methods]: Wild-type (WT) and PTP1B-KO mice were fed an OLA-supplemented diet (5 mg/kg/day, 7 months) or treated with OLA via intraperitoneal (i.p.) injection or by oral gavage (10 mg/kg/day, 8 weeks). Readouts of the crosstalk between hypothalamus and brown or subcutaneous white adipose tissue (BAT and iWAT, respectively) were assessed. The effects of intrahypothalamic administration of OLA with adenoviruses expressing constitutive active AMPKα1 in mice were also analyzed.[Results]: Both WT and PTP1B-KO mice receiving OLA-supplemented diet presented hyperphagia, but weight gain was enhanced only in WT mice. Unexpectedly, all mice receiving OLA via i.p. lost weight without changes in food intake, but with increased energy expenditure (EE). In these mice, reduced hypothalamic AMPK phosphorylation concurred with elevations in UCP-1 and temperature in BAT. These effects were also found by intrahypothalamic OLA injection and were abolished by constitutive activation of AMPK in the hypothalamus. Additionally, OLA i.p. treatment was associated with enhanced Tyrosine Hydroxylase (TH)-positive innervation and less sympathetic neuron-associated macrophages in iWAT. Both central and i.p. OLA injections increased UCP-1 and TH in iWAT, an effect also prevented by hypothalamic AMPK activation. By contrast, in mice fed an OLA-supplemented diet, BAT thermogenesis was only enhanced in those lacking PTP1B. Our results shed light for the first time that a threshold of OLA levels reaching the hypothalamus is required to activate the hypothalamus BAT/iWAT axis and, therefore, avoid weight gain.[Conclusion]: Our results have unraveled an unexpected metabolic rewiring controlled by hypothalamic AMPK that avoids weight gain in male mice treated i.p. with OLA by activating BAT thermogenesis and iWAT browning and a potential benefit of PTP1B inhibition against OLA-induced weight gain upon oral treatment.This work was funded by grants PID-2021-122766OB-100 (to AMV) and PID2019-104399RB-I00 (to GS) funded by Ministerio de Ciencia e Innovación/Agencia Estatal de Investigación /10.13039/501100011033 and “ERDF A way of making Europe” by the European Union. We also acknowledge grants H2020 Marie Sklodowska-Curie ITN-TREATMENT (Grant Agreement 721236, European Commission), S2017/BMD-3684 (Comunidad de Madrid, Spain), Fundación Ramón Areces (Spain) and CIBERdem (ISCIII, Spain) to AMV. JWE was funded by the Swedish Diabetes Foundation and the Novo Nordisk Foundation (NNF20OC0063864). VF was a recipient of a contract from ITN-TREATMENT and is currently a PhD fellow from the Portuguese Foundation for Science and Technology (FCT, Portugal)/ERDF (2020.08388.BD). CF was awarded with Sara Borrell contract (CD19/00078, ISCIII, Spain)

    Resonance capture cross section of 207Pb

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    The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.Comment: 7 pages, 3 figures, to be published in Phys. Rev.

    Desempenho preliminar de novos genótipos de aveia e trigo na Depressão Ccentral do RS

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    More than two hundred oat and wheat advanced-lines selected in 1983 were grown in field experiments at Guaíba, RS, Brazil, in 1984. The objective was to quantify, grain yield, 100 grain weight, hectoliter weight, biological yield, heading time, and plant stature. The results were significant for all traits, indicating that selection was efficient in oats; on the other hand, only one wheat-line showed superiority to the best check-variety.Mais de 200 linhagens avançadas de aveia (Avena sativa L.) e trigo (Triticum aestivum L.), selecionadas em 1983, foram avaliadas em dois experimentos, conduzidos em Guaíba, RS, durante o ano de 1984. O objetivo foi testar rendimento de grãos, peso do hectolitro e de 100 grãos, rendimento biológico, ciclo de desenvolvimento e estatura de planta. Os resultados foram significativos para todas as variáveis, indicando que a seleção tem sido eficiente na aveia; por outro lado, em trigo, somente uma linhagem mostrou superioridade em rendimento de grãos sobre a melhor cultivar-padrão

    Cost risk benefit analysis to support chemoprophylaxis policy for travellers to malaria endemic countries

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    BACKGROUND: In a number of malaria endemic regions, tourists and travellers face a declining risk of travel associated malaria, in part due to successful malaria control. Many millions of visitors to these regions are recommended, via national and international policy, to use chemoprophylaxis which has a well recognized morbidity profile. To evaluate whether current malaria chemo-prophylactic policy for travellers is cost effective when adjusted for endemic transmission risk and duration of exposure. a framework, based on partial cost-benefit analysis was used. METHODS: Using a three component model combining a probability component, a cost component and a malaria risk component, the study estimated health costs avoided through use of chemoprophylaxis and costs of disease prevention (including adverse events and pre-travel advice for visits to five popular high and low malaria endemic regions) and malaria transmission risk using imported malaria cases and numbers of travellers to malarious countries. By calculating the minimal threshold malaria risk below which the economic costs of chemoprophylaxis are greater than the avoided health costs we were able to identify the point at which chemoprophylaxis would be economically rational. RESULTS: The threshold incidence at which malaria chemoprophylaxis policy becomes cost effective for UK travellers is an accumulated risk of 1.13% assuming a given set of cost parameters. The period a travellers need to remain exposed to achieve this accumulated risk varied from 30 to more than 365 days, depending on the regions intensity of malaria transmission. CONCLUSIONS: The cost-benefit analysis identified that chemoprophylaxis use was not a cost-effective policy for travellers to Thailand or the Amazon region of Brazil, but was cost-effective for travel to West Africa and for those staying longer than 45 days in India and Indonesia
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