714 research outputs found

    Leverage Effect In Chinese And American Index Returns

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    A lot of changes have happened in the Chinese economy in the last three decades. To study whether these changes affect the symmetric or asymmetric behavior of the volatility in Chinese Stock Market, in this paper we analyze, first, the main stylized facts in similar Chinese and American index returns and, second, we compare the leverage effect of volatility in three different periods for these indexes.The estimated results with GJR-GARCH and TA-ARSV models have shown that the behaviour of Chinese index returns was different depending on whether China was part of the Trade World Trade Organization (WTO)

    Rankings In The Euro Zone Based On Macroeconomic Information

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    One consequence of the Great Recession that began in 2008 has been the sovereign debt crisis within the European Monetary Union (EMU) and the increasing risk premium associated with government debt of "peripheral" countries (primarily, Greece, Ireland, Portugal and Spain). Firstly, this paper analyses what macroeconomic variables are more related with the evolution of the risk premium, using panel data estimation. Secondly, we also try to sort the countries belonging to the monetary union in terms of their likelihood of experiencing an increase in the risk premium. To this purpose, we use discrete multicriteria decision aid methods

    Condiciones que favorecen la construcción de un ambiente propicio para el aprendizaje de la lectoescritura inicial en niños con dificultad en esta área

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    The objective of this study was to describe some of the conditions that intervenein the construction of a favorable environment for the teaching of boys and girls withliteracy difficulties. To achieve this, a qualitative study was carried out in a communitycenter in Guadalajara, Jalisco (Mexico). Data were collected through the observation ofthe classes between August 2019 and January 2020. A group of boys and girls -aged 7and 9- received educational support twice a week, as an after-school activity. From theanalysis, it is concluded that the display of the environment, the social organization ofthe classroom, the cooperation among peers, the positive feedback, and thecommunication of the meaning and purpose of the activities act as mediators in thelearning of literacy of boys and girls with said difficulties.Keywords: school environment, learning conditions, reading difficulty, teachingresources.El objetivo del estudio fue describir algunas de las condiciones que intervienen en la construcción de un ambiente propicio para el aprendizaje por parte deniños y niñas que presentan dificultades en el desarrollo de la lectoescritura. Para alcanzarlo, se realizó un estudio de naturaleza cualitativa; se llevó a cabo en un centro comunitario de la localidad de Guadalajara, Jalisco (México). Se recolectaron datos a través de la observación de las sesiones entre agosto de 2019 y enero de 2020. Participó un grupo de niños y niñas de 7 y 9 años de edad que asiste a recibir apoyo educativo dos veces a la semana, en turno contrario al horario escolar. A partir del análisis, se concluye que la disposición del ambiente, la organización social del aula, la ayuda entre pares, la retroalimentación positiva y la comunicación del sentido y propósito de las actividades actúan como mediadores en el aprendizaje de la lectoescriturade niños y niñas que han presentado dificultades para hacerlo. Palabras clave: ambiente escolar, condiciones de aprendizaje, dificultad para la lectura, medios de enseñanza

    Synthesis and reactivity of new silyl substituted monocyclopentadienyl zirconium complexes. X-ray molecular structure of [Zr{η5-C5H4(SiMe2CH2Ph)}(CH2Ph)3]

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    Synthesis and reactivity of new silyl substituted monocyclopentadienyl zirconium complexes. X-ray molecular structure of [Zr{η5-C5H4(SiMe2CH2Ph)}(CH2Ph)3]We are grateful to the DGICYT (Project PB-92-0178-C) and University of Alcalá for the financial support of this research

    La práctica reflexiva en los docentes de posgrado, comprender para transformar

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    Each of the world forums of education from Jomtiem, Thailand (1990), to Incheon, Republic of Korea (2015), have a fundamental objective which is the improvement of the quality of education, which requires substantive changes in teacher education that produce a series of competences for its professionalization.Professionalizing a teacher acquires a connotation of autonomy, expert knowledge and ability to build his own knowledge from his experience, a critical stance is assumed in the process of training and professionalisation where the development of a reflexive practice (RP), is required.The purpose of this scientific article is to communicate the process and results of an action research, from the diagnosis, design and implementation of intervention that consisted of a workshop based on the paradigm of reflexive practice for postgraduate teachers and finally the results of the evaluationThe theoretical reference was framed in authors that have contributed in the conceptual, methodological and technical issue in the field of reflexive practice, like Philippe Perrenoud, Donald Shön, Christopher Day, Kolb, J. Elliot, Domingo and Gómez, among others.En cada uno de los foros mundiales de educación desde Jomtiem, Tailandia (1990), hasta Incheon, República de Corea (2015), se planteó como un objetivo fundamental la mejora de la calidad educativa, para ello se demandan cambios  sustantivos en la formación docente que favorezcan una serie de competencias para su profesionalización.Profesionalizar al docente adquiere una connotación de autonomía, saberes expertos y capacidad de construir saberes propios desde su experiencia, se asume una postura crítica en el proceso de formación y profesionalización donde se requiere del desarrollo de una práctica reflexiva. El propósito de este este artículo científico es comunicar el proceso y resultados de una investigación acción, desde el diagnóstico, el diseño  y aplicación de intervención que consistió en un  taller fundamentado en el paradigma de práctica reflexiva para docentes de posgrado y finalmente los resultados de la evaluación. El referente teórico se enmarcó en autores que han aportado en lo conceptual, metodológico y técnico en el campo de la práctica reflexiva, como Philippe Perrenoud, Donald Schön, Christopher Day, Kolb, J. Elliot, Domingo A., entre otros

    Les Micotoxines i el seu control en els aliments

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    Ponència pronunciada el 16 demarç de 2007 en la jornada «L'oli d'oliva: del camp a la taula i més enllà», a Lleida. Les micotoxines són productes tòxics que provenen delmetabolisme secundari del fongs filamentosos. A causa de la seva incidència negativa sobre la salut de l'home i dels animals, es fa necessari l'establiment d'estratègies destinades al control de la seva presència i acumulació en els aliments. Aquestes han d'estar enfocades en les etapes inicials de la recol·lecció de lamatèria primera i en les etapes de postrecolecció i emmagatzematge. En cas que s'hagi produït la contaminació permicotoxines, és necessària l'aplicació demesures i estratègies de control que permetin assegurar la seva eliminació en els productes alimentaris, o almenys reduir els nivells per sota dels establerts per la legislació. Aquestsmètodes poden dividir-se en físics, químics i biològics. En aquest treball s'aporta una aproximació als sistemes de biocontrol descrits actualment.Mycotoxins are secondarymetabolites produced bymoulds. As they represent a big hazard for both human and animal health, it is necessary to find out effective strategies in order to control their presence in feed and food as well as their accumulation. These strategiesmust be focused on the harvest first stages and the post-harvest and storage stages. If amycotoxin contamination is detected, it is necessary to applymeasures and control strategies which guarantee its removal fromfeed and food, or at least to decrease the mycotoxin levels under the threshold established by legislation. Thesemeasures can be divided into physical, chemical and biological. This review introduces the biocontrol systems described so far

    A genome-wide association study follow-up suggests a possible role for PPARG in systemic sclerosis susceptibility

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    Introduction: A recent genome-wide association study (GWAS) comprising a French cohort of systemic sclerosis (SSc) reported several non-HLA single-nucleotide polymorphisms (SNPs) showing a nominal association in the discovery phase. We aimed to identify previously overlooked susceptibility variants by using a follow-up strategy.<p></p> Methods: Sixty-six non-HLA SNPs showing a P value <10-4 in the discovery phase of the French SSc GWAS were analyzed in the first step of this study, performing a meta-analysis that combined data from the two published SSc GWASs. A total of 2,921 SSc patients and 6,963 healthy controls were included in this first phase. Two SNPs, PPARG rs310746 and CHRNA9 rs6832151, were selected for genotyping in the replication cohort (1,068 SSc patients and 6,762 healthy controls) based on the results of the first step. Genotyping was performed by using TaqMan SNP genotyping assays. Results: We observed nominal associations for both PPARG rs310746 (PMH = 1.90 × 10-6, OR, 1.28) and CHRNA9 rs6832151 (PMH = 4.30 × 10-6, OR, 1.17) genetic variants with SSc in the first step of our study. In the replication phase, we observed a trend of association for PPARG rs310746 (P value = 0.066; OR, 1.17). The combined overall Mantel-Haenszel meta-analysis of all the cohorts included in the present study revealed that PPARG rs310746 remained associated with SSc with a nominal non-genome-wide significant P value (PMH = 5.00 × 10-7; OR, 1.25). No evidence of association was observed for CHRNA9 rs6832151 either in the replication phase or in the overall pooled analysis.<p></p> Conclusion: Our results suggest a role of PPARG gene in the development of SSc

    Prisoners in Their Habitat? Generalist Dispersal by Habitat Specialists: A Case Study in Southern Water Vole (Arvicola sapidus)

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    Habitat specialists inhabiting scarce and scattered habitat patches pose interesting questions related to dispersal such as how specialized terrestrial mammals do to colonize distant patches crossing hostile matrices. We assess dispersal patterns of the southern water vole (Arvicola sapidus), a habitat specialist whose habitat patches are distributed through less than 2% of the study area (overall 600 km2) and whose populations form a dynamic metapopulational network. We predict that individuals will require a high ability to move through the inhospitable matrix in order to avoid genetic and demographic isolations. Genotypes (N = 142) for 10 microsatellites and sequences of the whole mitochondrial Control Region (N = 47) from seven localities revealed a weak but significant genetic structure partially explained by geographic distance. None of the landscape models had a significant effect on genetic structure over that of the Euclidean distance alone and no evidence for efficient barriers to dispersal was found. Contemporary gene flow was not severely limited for A. sapidus as shown by high migration rates estimates (>10%) between non-neighbouring areas. Sex-biased dispersal tests did not support differences in dispersal rates, as shown by similar average axial parent-offspring distances, in close agreement with capture-mark-recapture estimates. As predicted, our results do not support any preferences of the species for specific landscape attributes on their dispersal pathways. Here, we combine field and molecular data to illustrate how a habitat specialist mammal might disperse like a habitat generalist, acquiring specific long-distance dispersal strategies as an adaptation to patchy, naturally fragmented, heterogeneous and unstable habitats

    Diet-Related Metabolites Associated with Cognitive Decline Revealed by Untargeted Metabolomics in a Prospective Cohort

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    Scope: Untargeted metabolomics may reveal preventive targets in cognitive aging, including within the food metabolome. Methods and results: A case-control study nested in the prospective Three-City study includes participants aged &65 years and initially free of dementia. A total of 209 cases of cognitive decline and 209 controls (matched for age, gen- der, education) with slower cognitive decline over up to 12 years are contrasted. Using untargeted metabolomics and bootstrap-enhanced penalized regression, a baseline serum signature of 22 metabolites associated with subsequent cognitive decline is identified. The signature includes three coffee metabolites, a biomarker of citrus intake, a cocoa metabolite, two metabolites putatively derived from fish and wine, three medium-chain acylcarnitines, glycodeoxycholic acid, lysoPC(18:3), trimethyllysine, glucose, cortisol, creatinine, and arginine. Adding the 22 metabolites to a reference predictive model for cognitive decline (conditioned on age, gender, education and including ApoE-ε4, diabetes, BMI, and number of medications) substantially increases the predictive performance: cross-validated Area Under the Receiver Operating Curve = 75% [95% CI 70-80%] compared to 62% [95% CI 56-67%]. Conclusions: The untargeted metabolomics study supports a protective role of specific foods (e.g., coffee, cocoa, fish) and various alterations in the endogenous metabolism responsive to diet in cognitive aging
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