2,813 research outputs found
Estudio de la influencia de la calidad del agua de riego sobre las propiedades bioquÃmicas del suelo
Trabajo presentado en el VII Simposio Nacional sobre Control de la Degradación y Restauración de Suelos, celebrado en Bilbao, España, del 23 al 26 de junio de 2015Este estudio analiza la influencia de la calidad del agua de riego sobre los parámetros bioquÃmicos de los Fluvisoles calcáricos representativos en dos zonas del sur de Alicante. Mediante un análisis de componentes principales (ACP) se obtuvo el PC1 (40% variabilidad), referente a la salinidad, siendo útil para diferenciar ambas zonas de estudio, y el PC2 (31%), englobando los parámetros bioquÃmicos, que distingue las muestras en función de la profundidad. Sin embargo, no se ha observado un efecto negativo sobre las principales actividades enzimáticas en el área más afectada por la salinización.Peer Reviewe
Phenotypic, Genetic and Environmental Architecture of the Components of Sleep Quality
The genetic and environmental underpinnings of sleep quality have been widely investigated. However, less is known about the etiology of the different sleep quality components and their associations. Subjective sleep quality has been studied most commonly using the Pittsburgh Sleep Quality Index (PSQI). Therefore, this work aimed to study the structure of sleep quality dimensions in a population-based twin sample by examining the etiology of the associations among the PSQI components themselves and between them. The sample comprised 2129 participants from the Murcia Twin Registry. In order to study the phenotypic, genetic and environmental structure of the PSQI we used three alternative multivariate twin models including all seven sub-scales of the PSQI (subjective sleep quality, latency, duration, efficiency, disturbances, use of sleeping medication and daytime dysfunction): a multivariate model (with seven separate correlated factors), a common pathway model and an independent pathway model. The multivariate correlated factors model showed the best fit to the data. All twin models indicated significant genetic overlap among most of the PSQI components, except daytime dysfunction and use of sleep medication. Bivariate heritability explained between 25 and 50% of the covariance for most associations between dimensions. Furthermore, the common pathway model showed that around one third of the variance (0.32; CI 95% 0.18.0.43) of a latent factor common to all questionnaire dimensions is explained by genetic factors. Genetic influences on a latent factor common to all questionnaire dimensions produced the same heritability estimates as the PSQI global score. However, sleep quality dimensions showed considerable specificity regarding its genetic-environmental structure.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. GRANT SUPPORT: Funding: Ministerio de Ciencia, Innovación y Universidades - Spain (RTI2018-095185-B-I00) co-funded by European Regional Development Fund (FEDER)
Psychological elements explaining the consumer's adoption and use of a website recommendation system: A theoretical framework proposal
The purpose of this paper is to understand, with an emphasis on the psychological perspective of the research problem, the consumer's adoption and use of a certain web site recommendation system as well as the main psychological outcomes involved. The approach takes the form of theoretical modelling. Findings: A conceptual model is proposed and discussed. A total of 20 research propositions are theoretically analyzed and justified. Research limitations/implications: The theoretical discussion developed here is not empirically validated. This represents an opportunity for future research. Practical implications: The ideas extracted from the discussion of the conceptual model should be a help for recommendation systems designers and web site managers, so that they may be more aware, when working with such systems, of the psychological process consumers undergo when interacting with them. In this regard, numerous practical reflections and suggestions are presented
Mode locking in discrete solition dynamics under ac forces
We present here analytical arguments and numerical evidence for the existence of net directional motion of highly discrete sine-Gordon kinks under ac forces of zero average. We have also characterized the depinning of the oscillating kink under those circumstances, and analyzed the instability mechanisms of the phase-locked running solutions. Possible experimental relevance of this phenomenon in circular arrays of Josephson junctions is discussed.Financial support from DGES (PB95-0797) and CICYT (MAT95-0325)Publicad
Acquisition of financial management skills in the new framework for adaptation to the EHEA. Póster
One of the main consequences of adapting to the
European Higher Education Area (EHEA) is the
replacement of traditional teaching methods, based
almost entirely on the lecture, with new methodologies
where active participation on the part of the students is
a key part of the teaching-learning process. It is,
therefore, of interest to offer empirical evidence
showing that the new teaching methods employed
really do serve to improve the results of the students in
the acquisition of skills. The aim of this paper is,
therefore, to assess the results obtained from bringing in
the new EHEA, compared to those obtained under the
traditional teaching system.
With the above aim in mind, we analysed the results
from the two existing groups of students studying
Financial Management I of the Degree in Business
Administration and Management (academic year
2009-10) at the Faculty of Economics and Business of
the University of Murcia. The first group comprised
students who had followed the course under the
traditional lecture-based teaching system. The second
group was made up of students taking part in the
innovation project being run by the Faculty of
Economics and Business. EHEA teaching methodologies
and materials have been employed in the second
group. Besides the lecture and the practical class, the
following teaching methodologies have been
employed: problem-based learning, workshops on
problems, group tutorials, group work and participative
models. The first group was assessed purely on the basis
of an end of semester examination, while in the case of
the second group, the final examination counted for
60% of the mark, 30% corresponded to individual work
and group practical work and 10% to participation in
class and responses to questions posed by the teacher.
It should be highlighted that the final examination was
the same for both groups, so the comparison o results is
free of bias in that aspect.
The results show that higher percentage of passes in the
group with innovative teaching – 93.75% versus 48.19%
in the lecture-based class group. The average grade
was also higher – 7.08 over 10 versus 4.52 over 10. These
differences are significant (t statistic 6.382 for the means
difference test). In order to rule out the possibility of
these better results being due to the assessment
awarded for the non similar parts of the examination, a
comparison was also made of the marks obtained
exclusively in the examination common to both groups.
While the number of passes (75%) and the average
mark of the group in the innovative method (6 over 10)
fall, the results remain significantly better than those of
the lecture-based classes group (t statistic for the
difference in mean marks was 2.485).Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci
Evaluación de la atención en deportistas de artes marciales : expertos vs. novatos
El objetivo del estudio fue determinar las diferencias en el desempeño de una tarea de atención en relación con la pericia en artes marciales. Participaron 12 deportistas de artes marciales expertos y 13 novatos. Se les aplicó el Test of Variables of Attention (Greenberg, 1996) y se analizaron los datos de la prueba para cada variable, condición y segmentos en los que se divide, con un método estadÃstico no-paramétrico de permutaciones. Las comparaciones intergrupos indicaron una tendencia a que el puntaje global de Trastorno por Déficit de Atención e Hiperactividad (TDAH) de la prueba fuera mejor en los expertos que en los novatos. Se hizo un análisis intragrupo para conocer el comportamiento de cada grupo a lo largo de la prueba; los resultados indicaron que los deportistas expertos muestran mayor consistencia en el número de aciertos y tiempos de reacción a lo largo de la prueba, lo que se traduce como un mejor desempeño cuando se compara con la forma en que los deportistas novatos responden a la tarea. Los resultados sugieren que el entrenamiento fÃsico y mental de las disciplinas de artes marciales podrÃa producir una mejora en las capacidades de atención de los deportistas.The aim of this study is to determine differences in the performance of an attention-related task involving martial arts skills. 12 expert martial arts athletes and 13 novices took part, performing the Test of Variables of Attention (Leark, Greenberg, Kindschi, Dupuy and Hughes, 2007). Using a non-parametric statistical permutation method, the test data for each variable, condition and segment of the test was analysed. Comparisons of the groups showed a trend toward a higher global Attention Deficit Hyperactivity Disorder (ADHD) score by the expert athletes as compared with the novices. In order to find out each group's performance during the test, a statistical intra-group analysis was performed. Generally, the results revealed more consistent accuracy and response times by the experts than by the novice athletes. The results suggest that physical and mental training in the martial arts may increase the attention skills of sportsmen and women.O objectivo do estudo foi determinar as diferenças no desempenho de uma tarefa atencional tendo em conta a perÃcia em artes marciais.Participaram no estudo 12 desportistas especialistas em artes marciais e 13 iniciantes. Foi aplicado aos participantes o Test of Variables of Attention (Greenberg, 1996) e analisaram-se os dados do teste para cada variável, condição e segmentos em que se dividem, através de um método estatÃstico nãoparamétrico de permutações. As comparações intergrupos indicaram uma tendência para que a pontuação global de Transtorno do Défice de Atenção e Hiperactividade (TDAH) fosse maior nos especialistas do que nos iniciantes. Foi realizada uma análise intragrupo para conhecer o comportamento de cada grupo ao longo da prova; os resultados indicaram que os desportistas especialistas revelaram maior consistência no número de acertos e tempos de reacção ao longo da prova, o que se traduz num melhor desempenho quando comparados com a forma como os desportistas iniciantes respondem à tarefa. Os resultados sugerem que o treino fÃsico e mental das disciplinas de artes marciais poderia produzir uma melhoria nas capacidades atencionais dos desportistas
Heritability of sleep quality in a middle-aged twin sample from Spain
©2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This document is the Accepted version of a Published Work that appeared in final form in Sleep. To access the final edited and published work see https://doi.org/10.1093/sleep/zsy110Study objectives: Sleep quality is associated with health throughout the life span,
which is particularly salient in middle-age and older adulthood. Sleep quality appears to
be influenced by both genetic and environmental factors. However, there is still limited
information about genetic influences on sleep quality in middle-aged adults, and
particularly in those from certain geographical locations. We estimated the magnitude of
genetic and environmental influences on sleep quality in a representative sample of
middle-aged Spanish twins.
Methods: The sample comprised 2150 individuals born between 1939 and 1966, who
participate in the Murcia Twin Registry. In order to estimate the heritability of sleep
quality variables we performed univariate analyses for the global score on the
Pittsburgh sleep quality index and for each of its components.
Results: We found moderate but significant heritability (34%) for sleep quality. The
genetic variance of the components of the Pittsburgh index ranged from 30% to 45%,
except for sleep efficiency for which no genetic influence could be detected. In
summary, there was a moderate genetic influence on most dimensions of sleep quality
in a sample of adult male and female twins. Shared environment influences were not
found.
Conclusions: This study adds new information regarding the underlying determinants
of sleep quality by providing heritability estimates in a middle-aged population-based
representative sample from a geographical location that has not been included in studies
of this type previously. This could provide a reference point for future research
regarding sleep research in middle-age
Energy efficient torus networks with on/off links
[EN] Future exascale computing systems will require energy and performance efficient interconnection networks to respond to the high data movement demands of new applications, such as those coming from big-data and artificial intelligence areas. The network structure plays a major role in the overall interconnect performance, for this reason torus is a common topology used in the current largest supercomputers. There are several proposals to improve energy efficiency of interconnection networks. However, few works combine both energy and performance, and sometimes they are treated as opposed issues. In this paper, we try to determine which torus network configuration offers the best performance/energy ratio when high-radix switches are used to build the interconnect system. The performance/energy evaluation has been performed by trace-driven simulation under realistic scenarios, where several mixes of scientific applications share a supercomputer system and are scheduled to be executed with the available resources at each moment.This work has been supported by the Spanish MINECO and European Commission (FEDER funds) under project TIN2015-66972-05-1-R and project TIN2015-66972-05-2-R. Francisco J. Andujar is also funded by the Spanish MINECO under a Juan de la Cierva grant FJCI-2015-26080.Andújar, FJ.; Coll, S.; Alonso DÃaz, M.; MartÃnez-Rubio, J.; López RodrÃguez, PJ.; Sánchez, JL.; Alfaro, FJ.... (2019). Energy efficient torus networks with on/off links. Journal of Parallel and Distributed Computing. 130:37-49. https://doi.org/10.1016/j.jpdc.2019.03.015S374913
Euphorbia paniculata Desf. subsp. paniculata en el sureste ibérico
Euphorbia paniculata Desf. subsp. paniculata in SE SpainPalabras clave. Euphorbia, CorologÃa, Murcia, Almeria, España.Keywords. Euphorbia, Chorology, Murcia, Almeria, Spain
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