A Combined Preconditioning Strategy for Nonsymmetric Systems

We present and analyze a class of nonsymmetric preconditioners within a normal (weighted least-squares) matrix form for use in GMRES to solve nonsymmetric matrix problems that typically arise in finite element discretizations. An example of the additive Schwarz method applied to nonsymmetric but definite matrices is presented for which the abstract assumptions are verified. A variable preconditioner, combining the original nonsymmetric one and a weighted least-squares version of it, is shown to be convergent and provides a viable strategy for using nonsymmetric preconditioners in practice. Numerical results are included to assess the theory and the performance of the proposed preconditioners.Comment: 26 pages, 3 figure

Risk factors for incidence and persistence of disability in chronic major depression and alcohol use disorders: longitudinal analyses of a population-based study

BackgroundMajor depression and alcohol use disorders are risk factors for incidence of disability. However, it is still unclear whether a chronic course of these health conditions is also prospectively associated with incidence of disability. The aim of the present study was, first, to confirm whether chronic major depression (MD) and alcohol use disorders (AUD) are, respectively, risk factors for persistence and incidence of disability in the general population; and then to analyze the role of help-seeking behavior in the course of disability among respondents with chronic MD and chronic AUD. MethodData from two assessments in the National Epidemiologic Survey on Alcohol and Related Conditions were analyzed. Disability was measured by eight domains of the Short Form 12 Health Survey version 2 (SF-12). Generalized estimating equations and logistic regression models were run to estimate risk factors for persistence and incidence of disability, respectively. ResultsAnalyses conducted on data from the US general population showed that chronic MD was the strongest risk factor for incidence and persistence of disability in the social functioning, emotional role and mental health domains. Chronic AUD were risk factors for incidence and persistence of disability in the vitality, social functioning, and emotional role domains. Within the group of chronic MD, physical comorbidity and help-seeking were associated with persistent disability in most of the SF-12 domains. Help-seeking behavior was also associated with incidence of problems in the mental health domain for the depression group. Regarding the AUD group, comorbidity with physical health problems was a strong risk factor for persistence of disability in all SF-12 domains. Help-seeking behavior was not related to either persistence or incidence of disability in the chronic alcohol group. ConclusionsChronic MD and chronic AUD are independent risk factors for persistence and incidence of disability in the US general population. People with chronic MD seek help for their problems when they experience persistent disability, whereas people with chronic AUD might not seek any help even if they are suffering from persistent disability.<br/

The role of fiscal rules and institutions in shaping budgetary outcomes

The Workshop "The role of fiscal rules and institutions in shaping budgetary outcomes" organized by the Directorate-General for Economic and Financial affairs of the European Commission on 24 November 2006 in Brussels aimed at enriching the debate on the fiscal arrangements and improving the understanding of their functioning. This Economic Paper contains all the paper presented in this event that was organised in four sessions. A first set of papers mainly focus on the impact of numerical fiscal rules on budgetary outturns. Other paper deal primarily with the appropriate design of fiscal rules and institutions. An additional group of papers addresses the relationship between the fiscal governance approach adopted by the EU Member States and their institutional and political frameworks. Finally the remaining presentations relate more directly to policy experiences. fiscal rules, budget, institutions.fiscal rules, budget, institutions, Ayuso-i-Casals, Deroose, Flores, Moulin

Analysis of surface variables and parameterization of surface processes in HIRLAM. Part I: Approach and verification by parallel runs

The analysis of surface variables and parameterization of surface processes of the reference HIRLAM system is described. Special emphasis has been put on the treatment of surface heterogeneity making that surface uxes of heat and momentum inherit such high spacial variability. The so called “tiling" approach has been adopted to prevent the problems associated with the use of efective parameters in case of strongly changing surface conditions. The tiles are defined by coupling independently each homogeneous patch or “tile" of a grid square to the lowest level of the model. Tiles interact each other only through the atmosphere. Average surface uxes are then computed by averaging surface uxes over each land-use tile weighted by their fractional area. The model allows up to five diferent tiles (water, sea ice, bare ground, low vegetation, forest) within each grid square. Fractional snow cover is also allowed within each tile. The ISBA scheme has been selected to model land surface processes. The surface analysis initializes the following surface variables: sea surface temperature (SST), fraction of water and ice, snow depth, 2-metre temperature, 2-metre relative humidity, surface soil temperature, mean soil temperature, surface soil water content and total soil water content. The algorithm is able to cope with the tiled structure by averaging some variables only over land tiles. SST and snow depth analyses are based on the successive correction method. 2-metre temperature and relative humidity analyses are based on the optimal interpolation method. Finally, soil water content analysis is based on the sequential method, which corrects water content depending on 2-metre temperature and relative humidity forecast errors, only in those synoptic cases where screen variables are strongly inuenced by the surface beneath. A comprehensive list of parallel runs covering all seasons of the year have been conducted to demonstrate the superiority of the new package against the previous surface treatment. Special emphasis has been put on summer time and midlatitude regions were the inuence of soil wáter content on screen temperature and humidity is extremely high

Analysis of surface variables and parameterization of surface processes in HIRLAM. Part II: Seasonal assimilation experiment

The HIRLAM analysis of surface variables and parameterization of surface processes described in the companion paper is applied to a one year long assimilation experiment in order to evaluate the performance of the new package over an extended period covering a complete annual hydrological cycle. The time evolution of the slow evolving variables and the usage of diagnostic tools to assess the performance of the surface analysis are thoroughly discussed in the text. In particular, the usefulness of the screen level variables and soil moisture analyses to diagnose and identify model biases is highlighted. There are also sections devoted to discuss the behaviour of different tiles within a grid square and the convergence of the assimilation algorithm. The need of soil moisture analysis is justified by an additional experiment showing the appearance of long-term drift in near surface parameters when soil moisture analysis is switched off

Effects of putrescine, cadaverine, spermine, spermidine and β-phenylethylamine on cultured bovine mammary epithelial cells

A bovine mammary epithelial cell line (BME-UV1) and three-dimensional collagen primary bovine organoids were used to evaluate the effects of cadaverine, putrescine, spermine, spermidine and β-phenylethylamine on mammary epithelial cells. Each biogenic amine was diluted in several concentrations (0-50 mM in BME-UV1 and 0-4 mM in primary bovine organoids) in the appropriate saline solution for the cell culture considered. In order to determine the activity of each compound tritiated thymidine incorporation was used. At low concentrations, all amines induced cell proliferation in both cultures. In BME-UV1, spermine significantly inhibited cell proliferation (P<0.001), while the other amines inhibited at higher concentrations (50mM). In primary bovine organoids, β−phenylethylamine significantly (P<0.001) inhibited cell proliferation at 4 mM. Organoids cultured in the presence of all amines, except β-phenylethylamine, had stellate projections indicating intense cell proliferation. Proliferation of mammary epithelial cells was stimulated at low concentrations, while at high concentrations it was inhibited. Our results suggested that the effects of each compound on mammary epithelial cells could be related to the compound itself and not to mediating by the bovine amino oxidase, responsible of the formation of toxic metabolites

Effects of ergo-nutritional strategies on recovery in combat sports disciplines

In order to improve the recovery process in combat sports disciplines, ergo-nutritional strategies could be an effective option in training and competition. Some of these ergo-nutritional aids could improve performance but literature references are scarce, with controversial results regarding actual recovery effects. This systematic review aimed to examine which ergo-nutritional methods are most effective for assisting in the recovery process in combat sports, and to determine the appropriate training stimuli. This systematic review was carried out following the Preferred Reporting Items for Systematic Review (PRISMA) guidelines. A computerized search was performed in PubMed, Web of Science, the Cochrane Collaboration Database, Evidence Database, Evidence Based Medicine Search review, National Guidelines, EM-BASE, Scopus and Google Scholar system (from 1995 to April 30, 2021). The PICOS model was used to define inclusion and exclusion criteria. Out of 123 studies initially found, 18 met the eligibility criteria and were included in the review. Data from 367 athletes from different disciplines were examined. The evidence was grouped in 4 areas: oxidative stress, muscle and energy recovery, muscle repair, and metabolic acidosis. Evidence showed that vitamins, minerals, and some natural ergo-nutritional products are effective as antioxidants. Carbohydrates and protein determine the recovery effect. Sodium bicarbonate has a role as primary acidosis metabolic delayer. Accordingly, ergo-nutritional aids can help in the recovery process. Considering the effects outlined in the literature, more studies are needed to provide firm evidence. Para mejorar el proceso de recuperación en las disciplinas deportivas de combate, las estrategias ergo-nutricionales son una opción eficaz en el entrenamiento y la competición. Algunas de estas alternativas mejoran el rendimiento, pero actualmente existe una escasa bibliografía con resultados controvertidos relacionados con el efecto de recuperación. Esta revisión sistemática tuvo como objetivo determinar qué estrategias ergo-nutricionales son más efectivas en los procesos de recuperación. Se llevó a cabo siguiendo las pautas Preferred Reporting Items for Systematic Review (PRISMA). Se realizó una búsqueda computarizada en PubMed, Web of Science, Cochrane Collaboration Database, Evidence Database, Evidence Based Medicine Search review, National Guidelines, EM-BASE, Scopus y el sistema Google Scholar (desde 1995 hasta el 30 de abril de 2021). Se utilizó el modelo PICOS para definir los criterios de inclusión y exclusión. De los 123 estudios encontrados inicialmente, 18 cumplieron los criterios de elegibilidad y fueron incluidos. Se examinaron datos de 367 atletas de diferentes disciplinas. La evidencia se agrupó en 4 áreas: estrés oxidativo, recuperación muscular y energética, reparación muscular y acidosis metabólica. La evidencia mostró que las vitaminas, los minerales y algunos productos ergo-nutricionales naturales son eficaces como antioxidantes, los hidratos de carbono y las proteínas determinan su efecto recuperador y el bicarbonato de sodio es el principal retardador metabólico de la acidosis. Se destaca la importancia de aceptar un plan ergo-nutricional para mejorar el proceso de recuperación. A pesar de ello, y teniendo en cuenta los efectos descritos en la literatura, se necesitan más estudios para reforzar la evidencia actual