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A Weak Comparison Principle for Reaction-Diffusion Systems
José Valero
Journal of Function Spaces and Applications , 2012, DOI: 10.1155/2012/679465
Abstract: We prove a weak comparison principle for a reaction-diffusion system without uniqueness of solutions. We apply the abstract results to the Lotka-Volterra system with diffusion, a generalized logistic equation, and to a model of fractional-order chemical autocatalysis with decay. Moreover, in the case of the Lotka-Volterra system a weak maximum principle is given, and a suitable estimate in the space of essentially bounded functions ∞ is proved for at least one solution of the problem.
Characterization of the Water Quality Status on a Stretch of River Lérez around a Small Hydroelectric Power Station
Enrique Valero
Water , 2012, DOI: 10.3390/w4040815
Abstract: The renewable energy emerged as a solution to the environmental problems caused by the conventional sources of energy. Small hydropower (SHP) is claimed to cause negligible effects on the ecosystem, although some environmental values are threatened and maintenance of an adequate water quality should be ensured. This work provides a characterization of the water quality status in a river stretch around a SHP plant on river Lérez, northwest Spain, for four years after its construction. The ecological and chemical status of the water as well as the ecological quality of the riparian habitat, were used as measures of quality. Data were compared with the water quality requirements. The variations in the quality parameters were analyzed over time and over the river sections with respect to the SHP plant elements. Two years after construction, the temperature and dissolved oxygen values achieved conditions for salmonid water and close to the reference condition, while pH values were low. The Iberian Biological Monitoring Working Party (IBMWP) index showed a positive trend from two years after the construction and stabilized at “unpolluted or not considerably altered water”. Quality parameters did not present significant differences between sampling points. The SHP plant construction momentarily altered the quality characteristics of the water.
Sistematización de la educación ambiental: teoría y práctica como fusión metodológica
Valero,Nay;
Educere , 2007,
Abstract: this article is part of a qualitative research paper developed in the field of the basic education 2nd stage (high school) in the caroní district in bolívar state, aiming to design a methodological proposal that contributes with environmental education (ea, in spanish) in the educational system. for its development, teacher ’s previous knowledge and current pedagogical practice were considered in the field of two general concepts involving the educational-environmental process, which are: environment and environmental education. the methodology allowed the interaction and construction of a pedagogical model to seize the process of incorporating and systematizing ea as a tool that allows current pedagogical practices integration with educational innovation according to the context. all of this was achieved thanks to the design of open questions structured survey-type instruments and interactive work workshops. the results were disintegrated from the conceptual aspects, the contrast with pedagogical practice, an approaching to curriculum local contextualization, to the construction of the methodology for the systematization of environmental education (pmsea, in spanish)
La educación ambiental en las Instituciones de educación superior del Estado Bolívar, Venezuela
Valero,Nay;
Revista de Pedagogía , 2008,
Abstract: the use of environmental education as a means of encouraging thought and discussion in the classroom may be seen as a tool that would allow us to establish strong ties between facilitators and promoters of this aspect of education with a view to constructing a pedagogical discourse that would have an impact on society as a whole with a view to transforming the prevalent anthropocentric and consumerist attitude towards the earth?s resources to one driven by the development of local potential within an integral, systematic framework. thus, environmental education seeks to re-establish those ties that would allow humanity to rediscover its relationship with nature through participation in and systemization of collective experiences. from this viewpoint this descriptive, explorative study was developed with the aim of identifying the pedagogical approaches to environmental education taken in the different higher education institutions (hei) in bolivar state, venezuela. the methodological approach used was that of participative diagnosis and it was found that environmental education only figured in 37 per cent of all the degree courses offered by hei in bolivar state. of these, the main approach taken tended to rely on theoretical classes. the programs were designed under different criteria which makes it difficult to standardize their structure and, in consequence, their scope from the environmental education point of view. on the whole, teaching centered on theoretical activities in the classroom and assessment mainly consisted of testing content knowledge.
Serie condiciones de trabajo en Colombia, Estrategias empresariales y diferenciación obrera: Anita Weiss de Belalcázar y Wigberto Casta eda N.
Valero Edgar
Revista Colombiana de Sociología , 1995,
Abstract: -
Sociología de la empresa. Del marco histórico a las dinámicas internas, de Sébastien Arcand, Rodrigo Mu oz, Joseph Facal y Jean Dupuis (eds.)
Valero édgar
Revista Colombiana de Sociología , 2010,
Abstract: Sociología de la empresa. Del marco histórico a las dinámicas internas, de Sébastien Arcand, Rodrigo Mu oz, Joseph Facal y Jean Dupuis (eds.)
El río minero: matagente, ladrón y fantasmal
Valero Helí
Maguaré , 2008,
Abstract: Desde una perspectiva émica, este artículo constituye una aproximación etnográfica al mundo de la explotación de esmeraldas en el occidente de Boyacá. Examina el complejo espectro de representaciones sociales asociadas al río Minero, cuyo carácter es el mismo de la zona y de sus gentes. El río Minero es un minero en efervescencia; reproduce los principios terribles de la lógica de la violencia y las economías extractivas en Colombia: es ladrón, es fantasmal y mata gente. Todas las narrativas que el autor explora redundan en el miedo, la fortuna, la desgracia, la riqueza y la crueldad. Así, de la mano de la experiencia de un visitante, concluye que la zona esmeraldera es el mismo infierno.
La fecundidad en Espa a Caída sin límites o recuperación?
ángeles Valero
Política y Sociedad , 1997, DOI: -
Abstract: Sin resumen
Discourses of Power in Mathematics Education Research: Concepts and Possibilities for Action (Discursos sobre el Poder en la Investigación en Educación Matemática: Conceptos y Posibilidades para la Acción)
Paola Valero
PNA , 2008,
Abstract: Mathematics education is powerful. This is an assertion that appears often in mathematics education research papers. However, the meaning of the assertion is far from being clear. An analysis of different ways of talking about power in relation to mathematics education, in research literature, is put forward. Three main discourses are identified: Power as an intrinsic capacity, power as structural imbalance, and power as distributed positioning. Identifying these discourses allows clarifying the values associated to mathematics education and the pedagogical imaginaries that are possible to envision for mathematics teaching and learning. La educación matemática es poderosa. Esta afirmación aparece con frecuencia en artículos de investigación; no obstante su significado no es siempre claro. Un análisis de las distintas maneras de hablar sobre el poder en relación con la educación matemática se ponen al descubierto en tres tipos de discursos: el poder como capacidad intrínseca, el poder como desequilibrio estructural y el poder como posicionamiento distribuido. La identificación de estos tres discursos permite elucidar los valores que se le atribuyen a la educación matemática, y hacer evidente los imaginarios pedagógicos posibles para pensar la ense anza y el aprendizaje de las matemáticas.
La Real Expedición Botánica a Nueva Espa a y los intentos de creación del Jardín Botánico de La Habana
Valero, Mercedes
Asclepio : Revista de Historia de la Medicina y de la Ciencia , 1995,
Abstract: The creation of a Botanical Garden in La Habana, at the beginning of the nineteenth century, was due to the efforts of the Real Sociedad Patriótica of La Havana and those of Martin de Sessé in 1795, member of the Botanical Expedition to Nueva Espa a, who was commissioner for the recognition of natural productions and the organization of botanical studies and gardens at the colonies. The arriving of Sessé awaken the interest of some members of the Real Sociedad Patriótica with respect to the proposition made in 1793. A few years later, the Havanan Garden was a reality. La formación de un Jardín Botánico en La Habana, a principios del siglo XIX, se debió a las esfuerzos de la Real Sociedad Patriótica de La Habana y conjuntamente con los de Martín Sessé en 1795, miembro de la Expedición Botánica a Nueva Espa a, que fue comisionado para el reconocimiento de las producciones naturales y la organización de estudios botánicos y jardines en las colonias. La llegada de Sessé despertó el interés de algunos miembros de la Real Sociedad Patriótica con respecto a la proposición hecha en 1793. A os más tarde, el jardín habanero fue una realidad.
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