134 research outputs found
Non-linear generalization of the sl(2) algebra
We present a generalization of the sl(2) algebra where the algebraic
relations are constructed with the help of a general function of one of the
generators. When this function is linear this algebra is a deformed sl(2)
algebra. In the non-linear case, the finite dimensional representations are
constructed in two different ways. In the first case, which provides finite
dimensional representations only for the non-linear case, these representations
come from solutions to a dynamical equation and we show how to construct
explicitly these representations for a general quadratic non-linear function.
The other type of finite dimensional representation comes from solutions to a
cut condition equation. We give examples of solutions of this type in the
non-linear case as well.Comment: 13 pages, 3 EPS figures, Late
Generalized quantum field theory: perturbative computation and perspectives
We analyze some consequences of two possible interpretations of the action of
the ladder operators emerging from generalized Heisenberg algebras in the
framework of the second quantized formalism. Within the first interpretation we
construct a quantum field theory that creates at any space-time point particles
described by a q-deformed Heisenberg algebra and we compute the propagator and
a specific first order scattering process. Concerning the second one, we draw
attention to the possibility of constructing this theory where each state of a
generalized Heisenberg algebra is interpreted as a particle with different
mass.Comment: 19 page
El perfil del alumnado repetidor y no repetidor en una muestra de estudiantes españoles y latinoamericanos: un estudio sobre los determinantes de sus logros académicos
El objetivo de esta investigación es describir
como una serie de variables que tienen incidencia
directa sobre los resultados académicos, caracterizan
al alumnado autóctono o latinoamericano repetidor y
no repetidor. Administramos una encuesta cuantitativa
a estudiantes de 5º y 6º de Enseñanza Primaria y de 1º
y 2º de Enseñanza Secundaria Obligatoria. Además,
recabamos información directa de sus familias sobre
los componentes de su estatus socioeconómico. Las
variables que mejor caracterizan al alumnado repetidor
son de carácter “sociocultural” o “estables en el
tiempo” y al no repetidor los factores “psicológicos” o
“cambiantes en el tiempo”. Se analizan las semejanzas
con estudios realizados en otros contextos educativos
que han servido para contrastar al modelo teórico
de base
¿Puede la implicación de los padres mejorar el estudio de sus hijos en la escuela? La evidencia de un programa pedagógico
En este trabajo pretendemos analizar la
actuación de las familias a la hora de implicarse en los
estudios de sus hijos/as adolescentes antes y después
de participar en un programa de educación familiar.
Participaron 79 familias de 7 centros con Educación
Secundaria Obligatoria. Los análisis nos permiten afi rmar
que hay diferencias signifi cativas en la actuación
de las familias a la hora de implicarse en los estudios
de sus hijos antes y después de participar en el programa.
Además, la implicación más efectiva en esta
etapa vital es la socialización académica frente a la
basada en la escuela y/o el hogar.This work is aimed at analyzing the way
families act when it comes to get involved in their
adolescent children’s studies before and after participating
in a family education program, which involved
79 families and 7 Compulsory Secondary Education
schools. The analyzes support the conclusion that
there are signifi cant differences in families’ behavior
when they get involved in their children’s education,
before and after participating in the program. In addition,
the most effective involvement at this vital stage
is the academic socialization, versus the school - and/
or home-based socialization
Putting the barker theory into the future : time to act on preventing pediatric obesity
Growth and development are key characteristics of childhood and sensitive markers of health and adequate nutrition. The first 1000 days of life\u2014conception through 24 months of age\u2014represent a fundamental period for development and thus the prevention of childhood obesity and its adverse consequences is mandatory. There are many growth drivers during this complex phase of life,such as nutrition,genetic and epigenetic factors,and hormonal regulation. The challenge thus involves maximizing the potential for normal growth without increasing the risk of associated disorders. The Mediterranean Nutrition Group (MeNu Group),a group of researchers of the Mediterranean Region,in this Special Issue titled \u201cPrevent Obesity in the First 1000 Days\u201d,presented results that advanced the science of obesity risk factors in early life,coming both from animal model studies and studies in humans. In the future,early-life intervention designs for the prevention of pediatric obesity will need to look at different strategies,and the MeNu Group is available for guidance regarding an appropriate conceptual framework to accomplish either prevention or treatment strategies to tackle pediatric obesity
El aprendizaje-servicio en la universidad: pedagogía y capital social para los estudiantes
Es un hecho que, al menos en España, con la puesta en marcha del Espacio Europeo
de la Educación Superior, la universidad creció en atención y sensibilidad estratégica
hacia determinadas cuestiones de corte pedagógico en su articulación curricular,
impulsando en los Campus planes de formación inicial y continua de su profesorad
Diseño y validación de un cuestionario sobre práctica docente y actitud del profesorado universitario hacia la innovación (CUPAIN)
Introducción: La institucionalización del Aprendizaje-Servicio (ApS) en la universidad recomienda, en primer lugar, el análisis de la cultura docente del profesorado y su actitud hacia la innovación. Precisamente, lo que este trabajo pretende es aportar un modelo teórico integrador desarrollando tres escalas de evaluación, contrastadas a través de pruebas estadísticas, para el contexto de la enseñanza universitaria en España. Metodología: A fin de elaborar el modelo de medida se aplicaron tres escalas a 1903 profesoras y profesores de 6 universidades españolas: una escala de práctica docente (18 ítems), otra sobre compromiso social de la universidad (9 ítems), y una tercera, sobre prácticas docentes innovadoras (11 ítems). Los datos obtenidos se sometieron a análisis factorial exploratorio y confirmatorio, además de realizar análisis de ítems y de consistencia interna de la escala. Resultados: La solución resultante ofreció en el caso de la práctica docente una escala final de 12 ítems, distribuidos en tres factores, con índices de ajuste satisfactorios: χ2 / gl = 8.6; GFI =.96; CFI = .93; RMSEA = .064; SRMR = .039. La segunda de las escalas, unifactorial, con los 9 ítems iniciales, cuenta con una elevada consistencia interna. Y la tercera de las escalas distribuye sus 11 ítems en dos factores que muestran índices de ajuste satisfactorios: χ2 / gl = 16.34; GFI =.93; CFI = .90; RMSEA = .090; SRMR = .049. Conclusión: Los resultados de los análisis factoriales realizados ofrecen una solución satisfactoria, tanto en la estructura factorial de las escalas como en los niveles de consistencia interna evaluados. Así, el modelo de medida propuesto integra las diversas aportaciones teóricas previas, y ofrece una escala complementaria que puede contribuir al avance de la investigación en ApS y, por extensión, en las Ciencias de la Educación
A imagem da ciência e as imagens visuais na formação superior e as pesquisas sobre o ensino de física
Impact of a Citywide Sanitation Program in Northeast Brazil on Intestinal Parasites Infection in Young Children
BACKGROUND: Sanitation affects health, especially that of young children. Residents of Salvador, in Northeast Brazil, have had a high prevalence of intestinal parasites. A citywide sanitation intervention started in 1996 aimed to raise the level of sewer coverage from 26% to 80% of households. OBJECTIVES: We evaluated the impact of this intervention on the prevalence of Ascaris lumbricoides, Trichuris trichuria, and Giardia duodenalis infections in preschool children. METHODS: The evaluation was composed of two cross-sectional studies (1998 and 2003-2004), each of a sample of 681 and 976 children 1-4 years of age, respectively. Children were sampled from 24 sentinel areas chosen to represent the range of environmental conditions in the study site. Data were collected using an individual/household questionnaire, and an environmental survey was conducted in each area before and after the intervention to assess basic household and neighborhood sanitation conditions. Stool samples were examined for the presence of intestinal parasites. The effect of the intervention was estimated by hierarchical modeling, fitting a sequence of multivariate regression models. FINDINGS: The prevalence ofA. lumbricoides infection was reduced from 24.4% to 12.0%, T. trichuria from 18.0% to 5.0%, and G. duodenalis from 14.1% to 5.3%. Most of this reduction appeared to be explained by the increased coverage in each neighborhood by the sewage system constructed during the intervention. The key explanatory variable was thus an ecological measure of exposure and not household-based, suggesting that the parasite transmission prevented by the program was mainly in the public (vs. the domestic) domain. CONCLUSION: This study, using advanced statistical modeling to control for individual and ecological potential confounders, demonstrates the impact on intestinal parasites of sanitation improvements implemented at the scale of a large population
Organic acids in diets of weaned piglets: performance, digestibility and economical viability
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