52 research outputs found

    On dividends and other quantities of interest in the dual risk model

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    Doutoramento em Matemática Aplicada à Economia e à GestãoNesta dissertação trabalhamos em teoria do risco. Damos principal ênfase principal nos modelos de risco e teoria de ruína, dedicando a nossa atenção a algumas das mais interessantes e relevantes quantidades da área: a probabilidade da ruína, a transformada de Laplace e os dividendos descontados esperados. Os modelos de risco têm o objetivo de resolver, ou pelo menos, fornecer uma solução aproximada, a problemas que aparecem na prática do negócio dos seguros. Os desenvolvimentos que produzimos nesta dissertação têm a mesma finalidade. A nossa intenção é apresentar novas ferramentas para o cálculo das quantidades mencionadas acima, e uma melhor compreensão delas na prática. Consideramos o modelo dual de risco quando os tempos entre ganhos seguem uma distribuição exponencial matricial e, quando for possível, dar exemplos dos nossos resultados para casos particulares, como as distribuições Phase–Type e Erlang. Mostramos, na maioria dos casos, fórmulas e fazemos uso de técnicas matemáticas de várias áreas, como a teoria da probabilidade, a teoria das equações integro–diferenciais, a ágebra linear, análise complexa, entre outras.In this manuscript we work on risk theory. The main emphasis is on risk models and ruin theory, devoting our attention to some of the most interesting and relevant quantities in this area: ruin probabilities, Laplace transforms and expected discounted dividends. Risk models are meant to solve or, at least, provide an approximate solution, to problems that appear in the practice of the insurance business. The developments we produce in this dissertation have the same goal. Our aim is to present new tools for computation of the quantities mentioned above, and a better understanding of them in the practice. We consider the dual risk model when the interclaim times follow a matrix exponential distribution and, whenever possible, we give examples of our findings for particular cases, like the Phase–Type, the Generalized Erlang and the Erlang distributions. We show, in most cases, explicit formulas and we make use of mathematical techniques from several areas, like probability theory, the theory of integro–differential equations, linear algebra, complex analysis, among others.info:eu-repo/semantics/publishedVersio

    A method to estimate endogenous losses of nitrogen and amino acids at the ileal level in growing rabbits

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    [EN] Apparent ileal digestibility can be corrected to give the true ileal digestibility of the nitrogen and amino acids provided by the diet, by determining the flow of endogenous nitrogen and amino acids (from desquamated epithelial cells of gastrointestinal mucosa, mucins and digestive enzymes). This flow of nitrogen and amino acids has been studied in adult rabbits fitted with a T-cannula, but remains unknown for growing rabbits. The aim of this work was to propose a method to estimate endogenous nitrogen and amino acid losses in the ileum of growing rabbits slaughtered at 64 d of age from 20:00 h. For this purpose, two experiments were carried out. The first was performed with 10 weaned rabbits fed with a diet with casein as the only source of protein (whose ileal digestibility is 100%) and labelled with ytterbium. This experiment allowed us to identify the relationship between the ileal flow of endogenous nitrogen (IFEN) and the dry matter intake in the last 24 h before slaughter (DMI), which fits the equation: IFEN (mg/d)=5.99 DMI (g/d) +133; (R2=0.778, residual standard deviation=138, P<0.001, n=10). The second experiment was carried out with 36 rabbits fed the same diet but without ytterbium, with whose ileal content 9 pools were constituted to determine the amino acid profile of endogenous nitrogen, which was found to be rich in glutamic acid, serine, aspartic acid, glycine, valine and threonine (15.97±1.33; 8.00±0.80; 7.06±0.72; 6.24±0.77; 5.48±0.51 and 4.97±0.47 g/16 g of N, respectively) and poor in methionine and histidine (1.05±0.06 and 1.34±0.16 g/16 g of N, respectively). Knowing the DMI of a certain growing rabbit in the 24 h prior to slaughter, the combined use of the equation and the amino acid profile obtained makes it possible to estimate the ileal endogenous losses of each amino acid.Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital of the Generalitat Valenciana (AICO/2021/256)Marín-García, PJ.; Rodríguez, M.; Ródenas, L.; Moya, VJ.; Martínez-Paredes, E.; López-Luján, MDC.; Cambra-López, M.... (2024). A method to estimate endogenous losses of nitrogen and amino acids at the ileal level in growing rabbits. World Rabbit Science. 32(1):1-9. https://doi.org/10.4995/wrs.2024.196541932

    White Paper 5: Brain, Mind & Behaviour

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    © CSICThe study of the brain will tell us what makes us humans and how our social behavior generates. Increasing our understanding of how the brain functions and interacts with the ecosystem to interpret the world will not only help to find effective means to treat and/or cure neurological and psychiatric disorders but will also change our vision on questions pertaining to philosophy and humanities and transform other fields such as economy and law. Neurosciences research at the CSIC is already valuable and should be intensified mainly focused on the eight major challenges described in this volume

    Dietary diversity and nutritional adequacy among an older Spanish population with metabolic syndrome in the PREDIMED-Plus study: a cross-sectional analysis

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    Dietary guidelines emphasize the importance of a varied diet to provide an adequate nutrient intake. However, an older age is often associated with consumption of monotonous diets that can be nutritionally inadequate, increasing the risk for the development or progression of diet-related chronic diseases, such as metabolic syndrome (MetS). To assess the association between dietary diversity (DD) and nutrient intake adequacy and to identify demographic variables associated with DD, we cross-sectionally analyzed baseline data from the PREDIMED-Plus trial: 6587 Spanish adults aged 55-75 years, with overweight/obesity who also had MetS. An energy-adjusted dietary diversity score (DDS) was calculated using a 143-item validated semi-quantitative food frequency questionnaire (FFQ). Nutrient inadequacy was defined as an intake below 2/3 of the dietary reference intake (DRI) forat least four of 17 nutrients proposed by the Institute of Medicine (IOM). Logistic regression models were used to evaluate the association between DDS and the risk of nutritionally inadequate intakes. In the higher DDS quartile there were more women and less current smokers. Compared with subjects in the highest DDS quartile, those in the lowest DDS quartile had a higher risk of inadequate nutrient intake: odds ratio (OR) = 28.56 (95% confidence interval (CI) 20.80-39.21). When we estimated food varietyfor each of the food groups, participants in the lowest quartile had a higher risk of inadequate nutrient intake for the groups of vegetables, OR = 14.03 (95% CI 10.55-18.65), fruits OR = 11.62 (95% CI 6.81-19.81), dairy products OR = 6.54 (95% CI 4.64-9.22) and protein foods OR = 6.60 (95% CI 1.96-22.24). As DDS decreased, the risk of inadequate nutrients intake rose. Given the impact of nutrient intake adequacy on the prevention of non-communicable diseases, health policies should focus on the promotion of a healthy varied diet, specifically promoting the intake of vegetables and fruit among population groups with lower DDS such as men, smokers or widow(er)s

    El grupu neandertal de la Cueva d'El Sidrón (Borines, Piloña).

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    Na monografía clásica de Puig y Larraz (1896: 250-252) amiéntense delles cavidaes del Conceyu de Piloña2 , pero non la Cueva d’El Sidrón (Fig. 1). Esta conocíase, ensin dulda, dende la Guerra Civil y el maquis al servir d’abellugu a persiguíos políticos, y guarda una alcordanza imborrable nuna de les sos múltiples entraes, yá qu’ellí ta enterrada Olvido Otero González (1908-1938). Per El Sidrón pasaron munches persones a lo llargo de los años, pero en 1994 prodúxose’l descubrimientu per parte d’unos espeleólogos xixoneses d’unos güesos humanos que dieron un importante xiru a la conocencia de los nuesos antepasaos neandertale

    Libro Blanco Volumen 5: Cerebro, mente y comportamiento

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    Llegar a entender cómo funciona el cerebro y cómo este interacciona con el ecosistema para interpretar el mundo que nos rodea sin duda facilitará el desarrollo de estrategias más eficaces para tratar o curar los trastornos neurológicos y psiquiátricos. Además, la comprensión de los principios fundamentales que controlan el funcionamiento del sistema nervioso transformará nuestra visión sobre muchas cuestiones que han sido tradicionalmente enmarcadas en el campo de la filosofía, repercutiendo en áreas como la economía o el derecho. Las neurociencias nos ayudarán, en definitiva, a entender qué nos hace humanos. Este es un campo en el que los investigadores del CSIC destacan internacionalmente y así debe seguir siendo en los próximos años. Para lograrlo, deberíamos potenciar y reforzar nuestras investigaciones en los ocho desafíos que describimos en este volumen.Peer reviewe

    Analysis of the common genetic component of large-vessel vasculitides through a meta- Immunochip strategy

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    Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P?=?7.54E-07; ORGCA?=?1.19, ORTAK?=?1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA?=?5.52E-04, ORGCA?=?1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus

    El grupu neandertal de la Cueva d'El Sidrón (Borines, Piloña)

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    Na monografía clásica de Puig y Larraz (1896: 250-252) amiéntense delles cavidaes del Conceyu de Piloña, pero non la Cueva d’El Sidrón (Fig. 1). Esta conocíase, ensin dulda, dende la Guerra Civil y el maquis al servir d’abellugu a persiguíos políticos, y guarda una alcordanza imborrable nuna de les sos múltiples entraes, yá qu’ellí ta enterrada Olvido Otero González (1908-1938). Per El Sidrón pasaron munches persones a lo llargo de los años, pero en 1994 prodúxose’l descubrimientu per parte d’unos espeleólogos xixoneses d’unos güesos humanos que dieron un importante xiru a la conocencia de los nuesos antepasaos neandertales.Peer Reviewe

    Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

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    Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide
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