Posibilidades didácticas de las Tecnologías de la Información y la Comunicación (TIC) en la docencia presencial

El presente trabajo recoge algunas de las experiencias desarrolladas por profesores de la Universidad de Navarra que, convencidos de las posibilidades de las tic para generar contextos de aprendizaje activos, cooperativos y autónomos, han decidido renovar sus estrategias didácticas. Estas prácticas vienen precedidas por una larga experiencia en esta universidad en la línea de apoyar y reforzar la enseñanza, prioritariamente presencial, con la utilización de las tic

Depth-dependent ordering, two-length-scale phenomena and crossover behavior in a crystal featuring a skin-layer with defects

Structural defects in a crystal are responsible for the "two length-scale" behavior, in which a sharp central peak is superimposed over a broad peak in critical diffuse X-ray scattering. We have previously measured the scaling behavior of the central peak by scattering from a near-surface region of a V2H crystal, which has a first-order transition in the bulk. As the temperature is lowered toward the critical temperature, a crossover in critical behavior is seen, with the temperature range nearest to the critical point being characterized by mean field exponents. Near the transition, a small two-phase coexistence region is observed. The values of transition and crossover temperatures decay with depth. An explanation of these experimental results is here proposed by means of a theory in which edge dislocations in the near-surface region occur in walls oriented in the two directions normal to the surface. The strain caused by the dislocation lines causes the ordering in the crystal to occur as growth of roughly cylindrically shaped regions. After the regions have reached a certain size, the crossover in the critical behavior occurs, and mean field behavior prevails. At a still lower temperature, the rest of the material between the cylindrical regions orders via a weak first-order transition.Comment: 12 pages, 8 figure

Depth-dependent critical behavior in V2H

Using X-ray diffuse scattering, we investigate the critical behavior of an order-disorder phase transition in a defective "skin-layer" of V2H. In the skin-layer, there exist walls of dislocation lines oriented normal to the surface. The density of dislocation lines within a wall decreases continuously with depth. We find that, because of this inhomogeneous distribution of defects, the transition effectively occurs at a depth-dependent local critical temperature. A depth-dependent scaling law is proposed to describe the corresponding critical ordering behavior.Comment: 5 pages, 4 figure

Synchronization in dynamical networks with unconstrained structure switching

We provide a rigorous solution to the problem of constructing a structural evolution for a network of coupled identical dynamical units that switches between specified topologies without constraints on their structure. The evolution of the structure is determined indirectly, from a carefully built transformation of the eigenvector matrices of the coupling Laplacians, which are guaranteed to change smoothly in time. In turn, this allows to extend the Master Stability Function formalism, which can be used to assess the stability of a synchronized state. This approach is independent from the particular topologies that the network visits, and is not restricted to commuting structures. Also, it does not depend on the time scale of the evolution, which can be faster than, comparable to, or even secular with respect to the the dynamics of the units.Comment: 8 pages, 3 figures. arXiv admin note: text overlap with arXiv:1407.074

Exact sampling of graphs with prescribed degree correlations

Many real-world networks exhibit correlations between the node degrees. For instance, in social networks nodes tend to connect to nodes of similar degree and conversely, in biological and technological networks, high-degree nodes tend to be linked with low-degree nodes. Degree correlations also affect the dynamics of processes supported by a network structure, such as the spread of opinions or epidemics. The proper modelling of these systems, i.e., without uncontrolled biases, requires the sampling of networks with a specified set of constraints. We present a solution to the sampling problem when the constraints imposed are the degree correlations. In particular, we develop an exact method to construct and sample graphs with a specified joint-degree matrix, which is a matrix providing the number of edges between all the sets of nodes of a given degree, for all degrees, thus completely specifying all pairwise degree correlations, and additionally, the degree sequence itself. Our algorithm always produces independent samples without backtracking. The complexity of the graph construction algorithm is ${\mathcal{O}}({NM})$ where N is the number of nodes and M is the number of edges

Cost-Benefit Analysis and Growth Effects of Pelleted and Unpelleted On-Farm Feed on African Catfish (Claries Gariepinus Burchell 1822) in Earthen Ponds

Fish feed constitutes 40-60% of the total operational costs of a fish farm. Commercial feeds are often too expensive for rural fish farmers. Consequently, farmers use non-conventional and locally available fish feed ingredients including agro-industrial by-products. These feeds have not led to increased pond productivity due to poor processing, higher fibre content, and anti-nutritional factors that limit nutrient bio-availability. Farmers have not embraced processing of fish feeds because the cost-effectiveness of processing has not been clearly demonstrated. The African catfish (Clarias gariepinus) is an important farmed fish in sub-Saharan Africa hence the need for research on its nutrition and growth performance. The growth performance and cost-benefit of using pelleted diets formulated from locally available feed ingredients on C. gariepinus were evaluated in a rural African setting. The experiment included diets that differed in the ingredients and form used (pelleted and un-pelleted). Four isocaloric and isonitrogenous diets were formulated from freshwater shrimp (Caridina nilotica), rice bran (Oryza sativa) and wheat bran (Triticum aestivum). The diets were C. nilotica and wheat bran pelleted (CWBp), C. nilotica and wheat bran un-pelleted (CWBup), C. nilotica and rice bran pelleted (CRBp), and C. nilotica and rice bran un-pelleted (CRBup). The diets were fed to C. gariepinus fingerlings (mean initial weight 1.75±0.03g), in triplicates for 5 months. The pelleted diets showed significantly better performance (P<0.05) compared to the un-pelleted diets. Fish grew to a weight of 266.77±6.21g on CWBp, 224.9±3.91g on CRBp, 211.38±4.46g on CWBup and 190.87±4.47g on CRBup. Cost benefit analysis of the pelleted and un-pelleted diets indicated positive net returns of US$180.1 for CWBp, US$142.5 for CRBp, US$126.8 for CWBup and US$ 115.5 for CRBup. The CWBp had significantly higher net returns than the other diets. This paper demonstrates that although on-farm pelleting of diets adds extra cost of labour, pelleted diets are cost-effective and should be incorporated as an essential part of on-farm feed production.Key words: Catfish, feed, pelleting, cost-effectiveness, pon

Teacher-student attachment relationship, variables associated, and measurement: A systematic review

This systematic review offers an overview of the results of research from the last 10 years con- cerning the teacher-student relationship and its connection with other attachment theory con- structs and child development variables. An exhaustive search of Web of Science, SCOPUS, and PsycINFO was performed, finding a total of 24 studies that met the established eligibility criteria. The evidence accumulated between 2010 and 2020 suggests that: 1) early care experiences have an effect on the formation of new relationships at primary school, although it is possible that children will construct new mental representations based on interactions in day to day life, 2) at the level of the teacher’s characteristics, attachment style and the availability towards children’s needs seem to be associated with school adjustment and problematic behaviour in children, and 3) the quality of the teacher-student relationship is significantly associated with externalizing and internalizing behaviour, school liking, peer acceptance, academic performance, self-concept and emotional regulation in children. For its part, when evaluating the quality of the teacher-student relationship, STRS continues to be widely used to study the teacher’s perspective. However, in recent years other measurement instruments have become available that explore the perspective of the student, most notably CARTS and SPARTS. Advances in the study of the teacher-student relationship as a bond with important implications for the development of children in the pri- mary education stage are discussed

Executive functions and their relationship with intellectual capacity and age in schoolchildren with intellectual disability

Background: There is certain empirical evidence of, on the one hand, a positive correlation between executive functions (EFs) and intelligence in people with intellectual disability (ID) and, on the other hand, a slower rate of development of EFs in these people relative to people without ID. This evidence is not, however, unequivocal, and further studies are required. Methods: We analysed the relationship between development of EFs and both age and intellectual capacity, in a sample of 106 students with either ID or borderline intellectual functioning (BIF) at a special education centre [63 boys and 43 girls, 11-18 years old, mean total intelligence quotient (TIQ) of 59.6]. We applied nine instruments to evaluate both neuropsychological development (working memory, inhibitory control, cognitive flexibility, planning, processing speed and verbal fluency) and behavioural development [teachers' perceptions of the EFs of their students by Behavior Rating Inventory of Executive Function - Second Edition (BRIEF-2) School]. ID and BIF groups were statistically compared in terms of mean performance measures in EF tests. We looked at the correlation between EFs and age, and correlations between EFs and intelligence: TIQ, fluid intelligence [measured by the perceptual reasoning (PR) sub-index of Wechsler Intelligence Scale for Children-IV (WISC-IV)] and crystallised intelligence (measured by the verbal comprehension (VC) sub-index of WISC-IV). Regression models were built for variables with strong correlation. Results: In most of the tests used to evaluate EFs, the ID subgroup performed significantly worse than the subgroup with BIF. In general, teachers' thought that participants had 'medium-low' levels of EFs. TIQ, by WISC-IV scale, correlated significantly with scores in all tests for all EFs. The PR sub-index correlated significantly with 14 of the tests for EFs; 35% of the variation in PR can be explained by variation in performance in Picture Span (working memory) and Mazes (planning). The VC sub-index correlated weakly with seven of the EF tests. We found significant correlations in the ID group between age and scores in all tests of working memory and inhibitory control. Age - considering all participants - did not correlate with any of the variables of teachers' perception except for working memory, and this correlation was not strong. Conclusions: The results of our study are consistent with descriptions of the typical population: (1) fluid intelligence is more related to EFs than crystallised intelligence is; and (2) working memory capacity is the EF most strongly related with general, fluid and crystallised forms of intelligence. The results suggest that as children and adolescents with ID/BIF get older, their capacities for working memory and inhibitory control increase; development of the other EFs studied was less evident. Teachers' perceptions of the EFs of children with ID or BIF were independent of intellectual capacity and age. More research is needed to delve further into the development of EFs in people with ID/BIF

O ensino das ciências experimentais no liceu, em Portugal, na I República (1910-1926)

O ensino das ciências experimentais (ECE) em Portugal ficou, como pretendemos demonstrar, fortemente marcado pela instauração da República, que comemorou no ano transacto o seu centenário. A República de 1910 pretendeu reformar toda a mentalidade portuguesa, através do pilar base – a educação – pela qual seria capaz de sacudir a nossa maneira de ser, lançando desta forma o país para um progresso de nível europeu. O estudo a que nos propomos, uma investigação documental no domínio da História da Ciência1, visa aprofundar os conhecimentos existentes sobre esta época e perceber o impacto da reforma do ECE, principalmente nos Liceus, caracterizando as principais figuras, políticas e docentes responsáveis pela sua conceptualização e aplicação. Através desta investigação procuraremos lançar as primeiras bases para descobrir as origens deste pensamento, querendo ainda comparar os fundamentos psicopedagógicos, epistemológicos e sociológicos da época com as principais ideias actualmente presentes no ensino da Ciência. Com este trabalho pretendemos, num primeiro momento, apresentar e divulgar o desenho da investigação e os seus objectivos, na procura de estabelecer parcerias e receber contributos da comunidade académica interessada por esta problemática