Alguns elements per a la motivació. Aspectes que desperten l’interès per les matemàtiques a l'aula

La motivació dels estudiants a les aules és un tema que preocupa a tots els professors de l’ensenyament. L’ideal seria que es pogués respondre a la pregunta “com es pot fer perquè els alumnes estiguin interessats a les aules?” Aquesta resposta encara no s’ha trobat, i tot apunta a que no sigui una resposta fàcil. En aquest treball es defineix un concepte clau dins el que és la motivació: la motivació intrínseca. Aquest tipus de motivació és la que fa que la gent faci activitats “perquè vol” i no perquè hi ha algun element extern que la força a fer-ho. A la definició es tracta de descriure, segons diferents autors, els components en que es pot dividir aquesta motivació. Al treball també es destaquen dos aspectes que controlen la motivació dels alumnes: el valor que donen als seus objectius i les atribucions causals que realitzen d’allò que perceben. Es proposen algunes actuacions a l’aula encarades a aprofitar aquests aspectes. S’ha fet també un breu estudi sobre dos tipus d’activitats de tipus no estàndard per a realitzar a l’aula. Per una banda, els problemes contextualitzats en les quals es basa la teoria de l’Educació Matemàtica Realista de l’escola Freudenthal, dels quals a la secció final del treball es porta una activitat concreta a l’aula, i d’altra banda, l’aprenentatge per projectes. A més, s’analitzen dues classes de matemàtiques a aules reals, identificant els elements de motivació utilitzats per professors diferents. Per últim, es descriu una activitat concreta que s’ha portat a l’aula: “L’aritmètica del rellotge”. És, com s’ha dit, del tipus “problema contextualitzat”. S’ha fet un petit anàlisi de l’actuació i de la valoració de l’activitat per part dels alumnes mitjançant una enquesta que han respost a l’aula

Cost-Effectiveness of Water Conservation Measures: A Multi-level Analysis with Policy Implications

Groundwater in Spain, as in other arid or semiarid countries worldwide, has been intensely used for the expansion of irrigated agriculture. This booming development has induced a remarkable socioeconomic development in many rural areas but has produced far-reaching environmental problems. In the Spanish Western La Mancha Aquifer, the excessive, and sometimes illegal, water abstraction for irrigation agriculture has resulted in the Aquifer’s overexploitation and has been responsible of the degradation of the associated wetlands “Tablas de Daimiel”, an internationally reputed, Ramsarnominated aquatic ecosystem. To undertake this analysis, a mathematical programming model has been developed to simulate farmers’ behaviour and their responses to different water policy scenarios. Specifically, the policy simulations selected are: alternative water pricing schemes (uniform volumetric and block-rate water tariffs), water use quota systems and water rights market. Results show that controlling illegal water mining is a necessary condition but it is not sufficient to recover the aquifer. Consequently, other measures will be necessary for an effective water management in this area. Among these, the block-rate water pricing scheme seems the most cost-effective system to reach the goal of aquifer sustainability but will entail important income losses in several farms. Therefore, we cannot conclude that a unique water conservation policy instrument will be the best overall solution for all types of holdings that will respond to efficiency as well as to equity considerations. It seems reasonable to make a combination of the tools proposed, even including additional measures that promote an environmental protection and develop sustainable agricultural systems.Environmental degradation, water policies, cost-effectiveness analysis, Resource /Energy Economics and Policy,

A generic template for FSSIM

Agricultural and Food Policy, Environmental Economics and Policy, Land Economics/Use,

Cell death and the immune response of the sipunculid worm Themiste petricola

We have recently studied the role of cell death in the immune system of the sipunculan worm Themiste petricola. Typical biochemical and morphological changes of apoptosis were induced in celomocytes of these marine worms after in vitro exposure of cells to hydrogen peroxide. Apoptosis was time and dose dependent, and required several hours to become apparent. Surprisingly, in unexposed samples a subtype of granulocyte was observed to undergo homotypic aggregation, extensive cytoskeletal changes, and degranulation followed by cell death. This spontaneous response ending in cell death occurred in a divalent cation-dependent manner, served to entrap foreign particles, and was blocked by EDTA-containing saline solutions. Even though the mode of granulocyte cell death shares some features with apoptosis, it appears to be a different form of programmed cell death since it occurs within minutes and does not produce single cell-derived apoptotic bodies but transforms itself into one or several syncytial masses with haemostatic and immune purposes. Since numerous granulocyte types and multicellular masses involved in cellular immunity have been described in sipunculan worms, the review also discusses the potential influence of activation of granulocytes by sea water in expanding the variety of morphological types and multicellular structures identified through morphological studies among sipunculan species.Fil: Blanco, Guillermo Armando C.. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral "Profesor R. A. Margni"; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Creación de un nuevo impedimento matrimonial por la Ley 23.515 : el menor emancipado cuyo matrimonio se ha disuelto

Fil: Blanco, Luis Guillermo. Universidad de Buenos Aires. Facultad de Derecho, Buenos Aire

Possible predation by Little Owl (Athene noctua) on nestling Red-billed Choughs (Pyrrhocorax pyrrhocorax)

Durant l'any 1992 es va fer un seguiment de 73 nius de gralla de bec vermell situats dins de masos als Monegros. En una ocasió es van trobar plomes de gralla de bec vermell amb signes de predació de rapinyaire prop d'un niu de mussol, i en una altra ocasió es van trobar restes òssies d'un poll de gralla en un niu de mussol. Això suggereix que les gralles de bec vermell poden patir la predació per part dels mussols

Clot Formation in the Sipunculid Worm Themiste petricola: A Haemostatic and Immune Cellular Response

Clot formation in the sipunculid Themiste petricola, a coelomate nonsegmented marine worm without a circulatory system, is a cellular response that creates a haemostatic mass upon activation with sea water. The mass with sealing properties is brought about by homotypic aggregation of granular leukocytes present in the coelomic fluid that undergo a rapid process of fusion and cell death forming a homogenous clot or mass. The clot structure appears to be stabilized by abundant F-actin that creates a fibrous scaffold retaining cell-derived components. Since preservation of fluid within the coelom is vital for the worm, clotting contributes to rapidly seal the body wall and entrap pathogens upon injury, creating a matrix where wound healing can take place in a second stage. During formation of the clot, microbes or small particles are entrapped. Phagocytosis of self and non-self particles shed from the clot occurs at the clot neighbourhood, demonstrating that clotting is the initial phase of a well-orchestrated dual haemostatic and immune cellular response