Módulo de enseñanza para desarrollar una mirada profesional sobre la comprensión matemática de los estudiantes

Una de las competencias docentes que debe desarrollar el futuro profesor de matemáticas es mirar de manera profesional el pensamiento matemático de los estudiantes. Por tanto uno de los objetivos de los programas de formación de profesores en el área de matemáticas es desarrollar esta competencia. En el Máster Universitario en profesorado de Educación Secundaria de la Universidad de Alicante se ha desarrollado un módulo con el objetivo de desarrollar esta competencia en el dominio del límite de una función en un punto. Este módulo tenía como objetivo crear oportunidades a los futuros profesores para que anticiparan, compartieran y consensuaran una hipotética trayectoria de aprendizaje del límite de una función en un punto en estudiantes de bachillerato. Los resultados muestran que el módulo permitió a los futuros profesores centrar su mirada en cómo los estudiantes de bachillerato aprenden el concepto de límite destacando el potencial de las tareas diseñadas para el desarrollo de la competencia

Temporal changes in the expression of the translocator protein TSPO and the steroidogenic enzyme 5a-reductase in the dorsal spinal cord of animals with neuropathic pain: effects of progesterone administration

Neuropathic pain is a frequent complication of spinal cord injury (SCI), still refractory to conventional treatment. The presence and biological activity of steroidogenic regulatory proteins and enzymes in the spinal cord suggests that neurosteroids locally generated could modulate pain messages. In this study we explored temporal changes in the spinal expression of the 18kDa translocator protein TSPO, the steroidogenic acute regulatory protein (StAr) and the steroidogenic enzyme 5-reductase (5α-RI/II) in an experimental model of central chronic pain. Male Sprague-Dawley rats were subjected to a SCI and sacrificed at different time points (1, 14 or 28 days). The development of mechanical and cold allodynia was assessed. Injured animals showed an early increase in the mRNA levels of TSPO and 5α-RII, whereas in the chronic phase a significant decrease in the expression of 5α-RI and 5α-RII was observed, coinciding with the presence of allodynic behaviors. Furthermore, since we have shown that progesterone (PG) administration may offer a promising perspective in pain modulation, we also evaluated the expression of steroidogenic proteins and enzymes in injured animals receiving daily injections of the steroid. PG-treated did not develop allodynia and showed a marked increase in the mRNA levels of TSPO, StAR, 5α-RI and 5α-RII 28 days after injury. Our results suggest that in the acute phase after SCI, the increased expression of TSPO and 5α-RII may represent a protective endogenous response against tissue injury, which is not maintained in the chronic allodynic phase. PG may favor local steroidogenesis and the production of its reduced metabolites, which could contribute to the antiallodynic effects observed after PG treatment. Fil: Coronel, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sánchez Granel, María Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Raggio, María Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Adler, Natalia Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: de Nicola, Alejandro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Labombarda, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana; ArgentinaFil: Gonzalez, Susana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana; Argentin

Application of a plant bioassay for the evaluation of ecotoxicological risks of heavy metals in sediments affected by mining activities

Purpose. The objective of this work was to evaluate the effectiveness of a plant bioassay (Phytotoxkit®) for screening ecotoxicological risks in sediments affected by mining activities. Materials and methods A total of 42 sediment samples affected by mining activities were studied, including 39 sediment samples fromthe Sierra Minera, Spain, an area affected by old extraction procedures, and three sediments from an area affected by opencast mining. These three samples were then mixed with limestone filler at 10, 20 and 30 %, providing nine stabilised samples. The total and soluble metal(loid) content (As, Cd, Cu, Fe, Pb and Zn) was determined in all samples, and the Phytotoxkit® bioassay was applied to determine the ecotoxicological effect of this procedure. Results and discussion The stabilised material had a neutral pH and low soluble metal(loid) concentration, similar to that of samples in which a natural attenuation process had taken place because of mixing with surrounding carbonate-rich materials. An ecotoxicological survey identified the low toxicity levels of the stabilised samples

Cost Optimisation for Minimizing the Visual Impact of Ornamental Stone Quarrying. A Case Study in Murcia Region

Quarrying of ornamental stone has adverse effects that are both visual and environmental. This paper aims to develop a methodology for minimising the costs associated with reducing the visual impact of ornamental stone quarrying. This study uses digital topographical maps of the study zone and a GPS and GIS application to calculate the extent of the area affected by quarrying activities for each altitude designated in the work plan and to calculate the extent of the potential visual impact. The results obtained applying the proposed methodology for the selected area suggested that the potential visual impact is minimal for an altitude of 520 metres, this being the optimal point for the observer. When altitude increases, the potential visual impact increases and the optimal point for the observer diminishes until the highest impact altitude (740 m) is readied. The optimal point that the exploitation should reach is that at which the values of the diagram generated by the (%) area of potential visual impact and area of exploitation (%) intersect. The methodology allows the optimal altitude to be determined for mining exploitations and helps assess the viability of a given exploitation from an environmental point of view

Cómo desarrollar una mirada profesional en futuros profesores de matemáticas

Una de las finalidades de los programas de formación de profesores en el área de matemáticas es desarrollar una “mirada profesional” sobre la enseñanza y aprendizaje. Esto implica ser capaz de identificar lo que es realmente importante en los procesos de enseñanza y aprendizaje vinculados a diferentes tópicos. En el marco del “Máster Universitario en profesorado de Educación Secundaria” de la Universidad de Alicante hemos desarrollado un módulo con el objetivo de desarrollar una “mirada profesional” sobre el proceso de generalización en la resolución de problemas. El módulo consistía en una tarea individual donde los futuros profesores debían describir las respuestas dadas por estudiantes de secundaria a dos problemas de generalización lineal y agrupar las que reflejaban características comunes de la comprensión del proceso de generalización; y participar en un debate virtual en el que debían discutir y consensuar un informe sobre las características de la comprensión del proceso de generalización. Los resultados indican que la tarea permitió a los futuros profesores centrar su mirada en las ideas que subyacen del proceso de generalización, más que en la corrección del procedimiento realizado, destacando el potencial de la tarea para el desarrollo de una mirada profesional en los programas de formación.Esta investigación ha recibido el apoyo del Proyecto I+D+i EDU2011-27288 del Ministerio de Ciencia e Innovación, España

Monitoring salinization processes in soils by using a chemical degradation indicator

The main aim of this work is to progress in the study of desertification processes in Mediterranean regions in the framework of DESERTNET project by means of the execution of pilot studies and development of evaluation models. This paper shows the results of an investigation on the degradation processes of soils carried out in the Murcia Region (SE, Spain). Specifically, salinization problems in Murcia Region were evaluated by means of two chemical degradation indicators, salinization state and salinization rate. We define chemical degradation indicator as the representative value of an observed chemical phenomenon in soil which produce its degradation. Chemical degradation indicators were calculated in order to simplify the interpretation of all the complex processes involved in environmental monitoring. The results obtained showed that in some areas an increase in salinization processes is taking place. On the other hand, there are only a few points with high a risk of salinization, obtaining similar results in the two periods of time studied

Trace element accumulation in plants from an aridic area affected by mining activities

Trace element contamination has been a serious problem in the vicinity of abandoned mine sites. In the studied area, mining activities have produced great amounts of wastes, characterized by high trace elements content, acidic pH and minerals from supergene alteration. Trace elements have been dispersed, both downstream and downslope from the mine mainly due, mainly, to surface run-off. Trace elements hydric mobilization usually takes place during the rainy season, an important pollution route in the studied area. A wide range of techniques have been proposed to remediate soils polluted by trace elements. Among them, phytoremediation-based technologies could provide a long-lasting solution. The aimof thisworkwas to determine trace element concentration in roots and leaves of five plant species (Limonium carthaginens, Arthrocnemum macrostachyum, Dittrichia viscosa, Glaucium flavum and Zygophyllum fabago) growing in soils polluted by mining activities in order to determine which part of the plants accumulate heavymetals to the greatest extent. Themetal concentrations in plants varied with plant species. Plant accumulation results showed that Z. fabago could act as an accumulator for Fe, and A. macrostachyum could accumulate in Fe, As and Mn. The other plant species collected from the mining sites were tolerant to trace element contamination

Geochemical and mineralogical characteristics of percolates and its evaporates from Technosols before and after limestone filler stabilisation

The chemistry of waters is recognized as a relevant monitoring tool when assessing the adverse effects of acid mine drainage. The weathering of sulphide minerals produces a great variety of efflorescences of soluble sulphate salts. These minerals play an important role for environmental pollution, since they can be either a sink or a source for acidity and trace elements. This communication deals with the leachability of potentially toxic elements (PTE) eluting from technosols formed from soils affected by mining activities and limestone filler. A total of three contaminated soils affected by opencast mining were selected and mixed with limestone filler at three percentages: 10 %, 20 % and 30 %, providing nine stabilised samples. These samples were stored in containers and moistened simulating rainfall. The percolates obtained were collected, and the PTEs content (As, Cd, Cu, Fe, Pb and Zn) was determined. Evaporation-precipitation experiments were carried out in these waters, and the mineralogical composition of efflorescences was evaluated. The study area is heavily polluted as a result of historical mining and processing activities, producing large amount of wastes, characterised by high trace elements content and acidic pH. The results obtained for the percolates after the rain episode showed that, before the stabilization approach, waters had an acidic pH, high electrical conductivity and high PTEs content. When these soils were mixed with 10, 20 and 30 % of limestone filler, the pH was neutral and the soluble trace element content strongly decreased, being under the detection limit when limestone percentage was 20 % and 30 %. The mineralogical composition of efflorescences before the stabilisation approach showed that predominant minerals were copiapite, followed by gypsum and bilinite. Other soluble sulphates were determined in lower percentage, such as hexahydrite, halotriquite or pickeringite. After the mixing with 10 % of limestone filler, the evaporates were mainly composed by gypsum and halite. Other minerals such as starkeyite (MgSO4·4(H2O), boyleite ((Zn,Mg)SO4·4H2O), tachyhidrite (CaMg2Cl6·12H2O) or bischofite (MgCl2) were quantified in low percentages. After mixing with 20 % and 30 % of limestone filler, main minerals were gypsum and halite, the presence of other phases being scarce. The addition of limestone filler to soils polluted by potentially toxic elements represents a useful and low impact strategy for reducing the soluble fractions of As, Cd, Cu, Fe, Pb and Zn. M.H.C. acknowledges the financial support of the Comunidad Autonóma de la Región de Murcia , Spain (Fundación Séneca, 19888/GERM/15

Histamine and Other Biogenic Amines in Food. From Scombroid Poisoning to Histamine Intolerance

Histamine is a biogenic amine involved in important physiological activities in the organism, but its ingestion through food is associated with the onset of health disorders. Histamine intoxication, previously known as scombroid fish poisoning, is caused by the intake of foods with high levels of histamine. According to official European Union reports, more than 90% of the outbreaks registered in the last years were caused by the consumption of fish and seafood products. Histamine intolerance, on the other hand, arises when histamine degradation is impaired, mainly by a lower diamine oxidase (DAO) activity. Some of the uncertainties classically associated with histamine intoxication may be explained by this enzymatic deficit in a sensitive population. This chapter reviews the adverse effects of histamine from food within a risk analysis framework, focusing specifically on the components of risk assessment and management

How prospective kindergarten teachers develop their noticing skills: the instrumentation of a learning trajectory

The objective of this study was to characterise prospective kindergarten teachers’ development of noticing children’s thinking about length and its measurement. We used the concepts of instrumental genesis and learning trajectories to identify the ways in which prospective kindergarten teachers used a learning trajectory to learn to notice children’s mathematical thinking. Following a teaching experiment, we identified three ways in which prospective kindergarten teachers used the learning trajectory to notice children’s mathematical thinking. Two instrumented action schemes supported these ways of using the learning trajectory, namely, a scheme taking into account the mathematics learning progression to interpret children’s answers, and a scheme for proposing instructional tasks based on the interpretation of children’s mathematical thinking. Approaching the development of noticing as an appropriation process of a learning trajectory helps us to understand prospective teachers’ difficulties in endowing meaning to a learning trajectory’s conceptual structure. We suggest that these ways of using learning trajectory knowledge to interpret children’s mathematical thinking and to make instructional decisions can be understood as an instrumentation process that reveals how noticing skills develop.This research was funded by the national Spanish Project: EDU2017-87411-R-‘Ministerio de Economía and Competitividad, Gobierno de España’