Cooperative Research As a Strategy for University Teacher Training. A Case Study of Lesson and Learning Study

This paper presents the possibilities offered by Lesson and Learning Studies for training and for improving and generating knowledge by reconstructing the practical knowledge of teachers. Firstly, we provide a summary of the concept of practical knowledge and the tradition of teachers researching their own practice. This is followed by some principles of Lesson and Learning Studies, with examples of their possibilities for university teacher training taken from a case study of our own practice during a university master's degree

Glyphosate-tolerant Asiatic dayflower (Commelina communis L.): Ecological, biological and physiological factors contributing to its adaptation to Iowa agronomic systems

Asiatic dayflower is a difficult weed to control with glyphosate, and has become a problem in glyphosate-tolerant soybean and corn for some Iowa farmers. Asiatic dayflower is an annual plant that is widely distributed in the temperate zones of the world. Also, this weed produces aerial dimorphic seeds, a common feature in other weeds belonging to the Commelinaceae. Asiatic dayflower dimorphic seeds can be described as truncated at one end and the other type described as being concave (i.e. non-truncated). Research investigating the biological and ecological characteristics that gives Asiatic dayflower an ecological advantage in glyphosate tolerant crops is lacking. Additionally, the tolerance mechanism of this weed to glyphosate is not fully understood. Therefore, this thesis is composed of three major experiments aiming to address ecology, biology and physiology characteristics that have allowed Asiatic dayflower to adapt to Iowa crop systems. The first experiment was designed to study emergence patterns and seedling emergence depths in two agronomic environments. In addition, seedling emergence depth was characterized by seed type in 2009 and 2010 to determine if dimorphic seeds represent an ecological advantage for Asiatic dayflower in different environments. Asiatic dayflower time of emergence varied by location and by year; emergence began early in May at Osceola and Vinton and continued until late July and early August at Osceola and Vinton fields, respectively. The number of Asiatic dayflower plants from truncated seeds exceeded those that emerged from non-truncated seeds. However, no differences were detected between seed types when seedling median depth of emergence was compared. Median depth of emergence ranged from 0.4 to 0.8 cm at the Osceola fields, and 2.2 to 2.4 cm at the Vinton field. A second experiment was established to study Asiatic dayflower emergence patterns using artificial seed banks. Artificial seed banks provided edaphic conditions that were similar to those found in agricultural fields but with known seed bank characteristics. Asiatic dayflower seeds were collected from natural infestations in fields near Osceola and Vinton, IA and seed collections were separated according to dimorphic seed type (i.e. truncated and non-truncated). Two artificial seed bank experiments were established at the Agronomy Farm and Curtiss Farm near Ames, IA during the fall 2009 and repeated fall 2010. Artificial seed banks consisted of PVC pipes buried in the ground, subsequently filled with soil mixed with a known quantity of Asiatic dayflower seeds; treatments consisted of seed origin and dimorphic type. After emergence, seedlings were counted and removed. During 2010, Asiatic dayflower seedlings started to emerge in early-May and emergence continued until mid-July at the Agronomy Farm, and from mid-April until mid-June at the Curtiss Farm. During 2011, seedling emergence started in April and continued until early-July and late-June at the Agronomy Farm and Curtiss Farm, respectively. Not all seeds in the artificial seed banks germinated. At both locations and in both years, total emerged seedlings from Osceola and Vinton truncated seeds planted in the artificial seed bank ranged from 35 to 65% and from 44 to 65%, respectively. However the total emerged seedlings from Osceola and Vinton non-truncated seeds ranged from 27 to 80% and 39 to 62%, respectively. Asiatic dayflower seedling emergence in artificial seed banks was likely affected by environmental conditions each year and the seed lot age used in the experiment. The third experiment addressed glyphosate uptake and translocation in Asiatic dayflower as a mechanism that may contribute to the tolerance observed in fields. Two experiments to investigate glyphosate uptake and translocation in Asiatic dayflower as well as the glyphosate rate response were conducted in the greenhouse. The first study characterized 14C-glyphosate uptake and translocation while the second study addressed the response of Asiatic dayflower to glyphosate dose. It was found that 14C-glyphosate uptake increased with time; glyphosate was primarily found in the treated leaf and translocated into the roots. At 2 and 48 hours after treatment, absorbed 14C-glyphosate in the treated leaf was 10 and 25% of the total 14C-glyphosate applied, respectively. Absorption of 14C-glyphosate in the roots at 2 and 48 hours after treatment was 2 and 9 % of the total 14C-glyphosate applied, respectively. Only small amounts of 14C-glyphosate were found in other plant parts (i.e. tissue above and below the treated leaf). Asiatic dayflower response to glyphosate doses was measured as plant growth relative to the untreated control. Asiatic dayflower growth varied across the repeated experiments. Asiatic dayflower growth exceeded that of the untreated control plants by 31 and 74 % in the first and second experiments, respectively, when glyphosate was applied at 0.63 kg a.e. ha-1. Conversely, growth relative to the untreated control plants in the third experiment was lower for plants treated with 0.63 kg a.e. ha-1 of glyphosate when compared to the untreated control plants. The Brain-Cousens model best described the data for experiments 1 and 2 because it accounts for the hormetic effect caused by sub-lethal doses; the log-logistic model best described the data for the third trial where no hormesis was detected. The base dose (i.e. 1.26 kg a.e. ha-1) and higher doses decreased Asiatic dayflower growth relative to the untreated control

Modelling Euro-Mediterranean Agricultural Trade

This paper examines the methodological problems to define a modelling approach to assess the impact of full or limited bilateral liberalisation of agricultural trade flows in the Euro-Mediterranean region. The bilateral trade liberalisation process in the region is framed by complexity, in policy instruments and in the characteristics of the products, in particular fruits and vegetables. Advantages and disadvantages of the general equilibrium and partial equilibrium approaches to simulate trade policy impacts are assessed. Caveats of existing models are related to the representation of specific policy instruments (tariffs, entry prices and other non-tariff measures) and on the seasonal nature of horticultural trade, which is of major importance in the Euro-Mediterranean Free Trade Are. The paper provides an illustration of how an imperfect substitute product model could be helpful to describe the trade effects of bilateral price changes, for given seasons.

Rheological study of the aggregation state of alumina nanofluids

Se adjunta una comunicación, aunque se han publicado tres comunicaciones más.The presence of alumina solid particles in aqueous phase induces a change in the viscosity of the suspension from Newtonian to non- Newtonian flow. Besides, the presence of solid particles is adequate for the use as a heat exchanger fluid. The effect of nanoparticle size on thermal properties of nanofluids is still today a question, which is far from being answered. In this respect, the results reported in the literature are contradictory [1], probably due to the formation of aggregates when particles are dispersed in the liquid phase. Regarding to the nanoparticle shape influence in thermal conductivity, cylinders and spheres have been considered as the more effective in heat transfer. Spherical nanoparticles of alumina, which is one of the most investigated nanofluid, dispersed in water were used in this study. TEM images showed a mean average diameter of 50 nm. However, DLS measurements showed monodispersed particles of 260 nm. Very recently [2], the relationship between shear rheology and aggregation state of suspensions has been reviewed. Mechanical and physical properties of the resultant materials depend on shape, size and size distribution, which are considered determining parameters in the formation of particle aggregates. The steady shear flow (figure 1) has shown that these clusters, when they are at rest, are formed by highly branched aggregates that erode when shear rate increases, until a suspension of individual particles is achieved. These results are in good agreement with the intrinsic viscosity obtained by Money and Krieger-Dougherty models. In both cases, these values are far from the 2.5 corresponding to spherical particles. The temperature effects were also taken into account.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Heat transfer enhancement using nanofluids in the compression exchanger in a solar Stirling engine

In this paper a improvement in the heat exchange of a solar Stirling engine during the compression phase was studied. The viability of using nanoparticles as ceramic oxide (Al2O3 in water) at different concentrations instead of conventional refrigerants (water or air) was evaluated. Since these systems could behave as non- Newtonian fluids the dynamic viscosity was measured, as well as other thermophysical properties. The results showed that the convective heat transfer coefficient could raise one order of magnitude respect to the conventional heat transfer fluids at moderately volume fractions (over 0.15).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

F&V Trade Model to Assess Euro-Med Agreements. An Application to the Fresh Tomato Market

The complexity derived from the bilateral trade liberalisation process in the Mediterranean region is difficult to represent in a trade model, not only because of the range of instruments still constraining trade but also because of the special nature of the most important traded goods (product differentiation and seasonality). Tariff-rate quotas (TRQ's) and the entry price system are clearly defined on a monthly basis for the fruits and vegetables trade flows towards the European Union (EU). This point makes efforts to model such a trade in yearly basis not representative of reality. We propose a static partial equilibrium model tailored to model trade impacts of specific policy instruments which considers imports from different sources as imperfect substitutes, following the non-linear Armington type model. Different policy scenarios have been run using the model, considering changes in TRQ's and Entry Price regimes, its tariffication and preference erosion. The results of model runs show that, as regards to EU producers, bilateral trade liberalisation with extension of TRQs would be the least dramatic scenario. By contrast, the phasing out of the entry price system would have serious consequences on EU producers. The model has also given detailed information on Morocco's interests in the negotiation, although it could easily include a larger number of suppliers. Morocco appears to be interested in multilateral liberalisation as well as in bilateral liberalisation. In fact, multilateral liberalisation will not cause a great deal of preference erosion against Moroccan exporters, unless tariff reductions only affect MFN suppliers.International Relations/Trade,

Characterization and thermophysical properties of rutile and alumina nanofluids

The characterization in relation to shape and particle size of alumina and rutile suspensions was performed. The intrinsic viscosity exhibited the presence of nonspherical aggregates in both suspensions although TEM images showed non monodisperse spherical shape of alumina particles. DLS indicated the existence of particle aggregates for both systems. In all cases, the increase in thermal conductivity with respect to the base fluid is verified. The thermal conductivities obtained experimentally were compared with three mathematical models, which yielded lower values than those measured. From rheological measurements and by means of the Peclet number defined in colloidal suspensions, values of thermal conductivity were also proposed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec