Innovación pedagógica para las clases de laboratorio de física

The pedagogical innovation here presented has the following objectives: 1- To observe the disposition of students to participate in the group task through the distribution of tasks, the discussion of ideas, the organization and the commitment for the work to carry out. 2- To observe in students the use of critical thinking in the analysis of data, in its interpretation and in the elaboration of conclusions and a laboratory report. The registered students in 2009 in the General and Biological Physics were distributed to groups of 6 members. Each group conducted the laboratory experience and a written report of every practical work (PW). Two categories, one for laboratory tasks and one for the laboratory notebook were used to evaluate the activities carried out by students. The obtained notes by group and PW under both headings depended on the group. The groups performances was better in the laboratory activities than in the notebook. The workgroup encouraged students to achieve a signifi cant learning. However, not having read the theoretical concepts limited the groups to take the initiative to begin the experience and it took them to read the guide simultaneously to fulfi l the PW. This lack of knowledge was also refl ected at the time of emitting the conclusions in the laboratory report

Comparación de cebos tóxicos en sus propiedades físicas

p.197-203El objetivo de este trabajo fue comparar algunas propiedades físicas del cebo tóxico Dual con dos crustaticidas y dos molusquicidas de venta comercial utilizados para el control de bichos bolita y babosas, respectivamente. Se utilizaron cinco cebos tóxicos: Molusquicida Acay y Clartex, Crustaticida Acay y Clartex y Dual Acay en pellets de forma cilíndrica. Las propiedades físicas determinadas en cada cebo fueron uniformidad de tamaño, densidad real y aparente, porcentaje de humedad, resistencia a la rotura por carga dinámica y persistencia. El Dual presentó dimensiones que llevan a obtener menor área específica que el resto de los cebos tóxicos, excepto Molusquicida Clartex. Esto trae como consecuencia que la cantidad de pellets para la misma masa sea también menor, por lo que sería necesario mayor o igual dosis pero con cantidad de ingrediente activo mayor por pellet para alcanzar control similar que un producto de menores dimensiones. Los pellets del Dual se ubicaron en una posición intermedia de densidad real (1,25 g cm-3) y aparente (0,81 g cm-3), porcentaje de humedad (11,12 por ciento) y de rotura (36,88 por ciento) con respecto a los molusquicidas y crustaticidas. El Dual presentó mayor persistencia, característica que permitiría aumentar el tiempo durante el cual mantiene su toxicidad

Holistic Assessment of Calcium Fertilization in Potato: Diagnostic, Productivity, and Tuber Quality

Calcium (Ca) deficiency could negatively affect potato (Solanum tuberosum L.) tuber yield and quality. Therefore, it is required to develop Ca diagnostic methods and assess the impact of Ca fertilization on tuber yield and quality (dry matter and starch concentration, resistance to mechanical damage, and sensory texture attributes such as firmness, mealiness, granularity, and moisture). Field trials evaluating three Ca rates (0, 40, and 80 kg ha−1) were performed for six site-years. Soil exchangeable Ca (Cae) (0–20 cm) at planting and leaf Ca concentration (CaL) at tuber bulking were measured. At harvest, tuber yield, tuber quality parameters, and tuber Ca concentration (CaT) were determined. On average, across site-years, Ca fertilization increased tuber yield, CaT, and CaL by 16, 14, and 17%, respectively. Yield response to Ca increased 4.5 Mg ha−1 for each cmolc kg−1 reduction in soil Cae below 11.3 cmolc kg−1, while it increased 1.7 Mg ha−1 for each 0.1 g 100 g−1 reduction in CaL below 1.05 g 100 g−1. Calcium fertilization increased tuber dry matter (5%), starch (13%), and sensory texture attributes, mainly firmness (103%) and mealiness (70%). Also, these parameters were positively associated with CaT. The mechanical damage depth and mechanical damage index decreased with increments in Ca rate and CaT. Under Ca deficiencies, Ca fertilization is a recommended management practice for improving potato yield and quality while reducing tuber mechanical damage.EEA BalcarceFil: Giletto, Claudia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Kloster Erreguerrena, M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Ceroli, Paola. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Carciochi, Walter. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Carciochi, Walter. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Silva, Sandra. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Rodriguez, Silvia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros; Argentina.Fil: Reussi Calvo, Nahuel Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Reussi Calvo, Nahuel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Holistic Assessment of Calcium Fertilization in Potato: Diagnostic, Productivity, and Tuber Quality

Calcium (Ca) deficiency could negatively affect potato (Solanum tuberosum L.) tuber yield and quality. Therefore, it is required to develop Ca diagnostic methods and assess the impact of Ca fertilization on tuber yield and quality (dry matter and starch concentration, resistance to mechanical damage, and sensory texture attributes such as firmness, mealiness, granularity, and moisture). Field trials evaluating three Ca rates (0, 40, and 80 kg ha−1) were performed for six site-years. Soil exchangeable Ca (Cae) (0–20 cm) at planting and leaf Ca concentration (CaL) at tuber bulking were measured. At harvest, tuber yield, tuber quality parameters, and tuber Ca concentration (CaT) were determined. On average, across site-years, Ca fertilization increased tuber yield, CaT, and CaL by 16, 14, and 17%, respectively. Yield response to Ca increased 4.5 Mg ha−1 for each cmolc kg−1 reduction in soil Cae below 11.3 cmolc kg−1, while it increased 1.7 Mg ha−1 for each 0.1 g 100 g−1 reduction in CaL below 1.05 g 100 g−1. Calcium fertilization increased tuber dry matter (5%), starch (13%), and sensory texture attributes, mainly firmness (103%) and mealiness (70%). Also, these parameters were positively associated with CaT. The mechanical damage depth and mechanical damage index decreased with increments in Ca rate and CaT. Under Ca deficiencies, Ca fertilization is a recommended management practice for improving potato yield and quality while reducing tuber mechanical damage.Fil: Giletto, Claudia Marcela. Universidad Nacional de Mar del Plata; ArgentinaFil: Kloster Erreguerrena, M.. Universidad Nacional de Mar del Plata; ArgentinaFil: Ceroli, Paola Susana. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Silva, Sandra Elizabeth. Universidad Nacional de Mar del Plata; ArgentinaFil: Rodriguez, Silvia. Universidad Nacional de Mar del Plata; ArgentinaFil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Oliveros; ArgentinaFil: Reussi Calvo, Nahuel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentin