Segmentación fonológico-silábica y adquisición de la lectura: un estudio empírico

El artículo presenta una investigación cuyos resultados muestran la menor capacidad de segmentación silábica entre aquellos niños con peor habilidad lectora. Plantea también la funcionalidad, facilidad de aplicación y carácter motivador de la prueba realizada—una tarea de ordenador—para evaluar la capacidad de segmentación.     

Online undergraduate students’ perceptions of the impact of Web 2.0 on higher education / Percepciones de estudiantes de licenciatura en línea sobre el impacto de la Web 2.0 en educación superior

Abstract

Although Web 2.0 has changed students’ roles, placing them at the centre of the teaching-learning process, attitudes towards Web 2.0 have been observed to have a relation with its use in a formal academic context. An instrument was applied to higher education students in Mexico to explore their perceptions by collecting information on students’ attitudes, training and use of Web 2.0, and its impact on higher education. The findings showed that training in Web 2.0 determines use of it, as well as the attitudes towards it and the possible impact these can have on teaching-learning processes. No differences were found regarding participants’ gender in relation to their perceptions of the use of Web 2.0 as a learning environment.     

What makes companies pursue an Open Science strategy?

Whereas recent scholarly research has provided many insights about universities engaging in commercial activities, there is still little empirical evidence regarding the opposite phenomenon of companies disseminating scientific knowledge. Our paper aims to fill this gap and explores the motivations of firms that disclose research outcomes in a scientific format. Besides considering a dimension internal to the firm, we focus particularly on knowledge sourcing from academic institutions and the appropriability regime. We conduct an econometric analysis with firm-level data from the fourth edition of the French innovation survey (CIS) and matched scientific publications for a sample of 2512 R&D performing firms from all manufacturing sectors. This analysis provides evidence that firms are more likely to adopt academic principles if they need to access scientific knowledge that is considered important for their innovation development, whereas the mere existence of collaborative links with academic institutions is not a strong determinant. Furthermore, the results suggest that the inclination of firms to publish is sensitive to the level of knowledge spillovers in a sector and the effectiveness of legal appropriation instruments.     

Evaluating the impact of R&D tax credits on innovation: A microeconometric study on Canadian firms

This study examines the effect of R&D tax credits on innovation activities of Canadian manufacturing firms. Over the 1997-1999 period the Federal and Provincial R&D tax credit programs were used by more than one third of all manufacturing firms and by close to two thirds of firms in high-technology sectors. We investigate the average effect of R&D tax credits on a series of innovation indicators such as: number of new products, sales with new products, originality of innovation, etc. using a non-parametric matching approach. Compared to a hypothetical situation in the absence of R&D tax credits, recipients of tax credits show significantly better scores on most but not all performance indicators. We therefore conclude that tax credits lead to additional innovation output.     

W5″ Test: A simple method for measuring mean power output in the bench press exercise

The aims of the present study were to assess the validity and reliability of a novel simple test [Five Seconds Power Test (W5″ Test)] for estimating the mean power output during the bench press exercise at different loads, and its sensitivity to detect training-induced changes. Thirty trained young men completed as many repetitions as possible in a time of ≈5?s at 25%, 45%, 65% and 85% of one-repetition maximum (1RM) in two test sessions separated by four days. The number of repetitions, linear displacement of the bar and time needed to complete the test were recorded by two independent testers, and a linear encoder was used as the criterion measure. For each load, the mean power output was calculated in the W5″ Test as mechanical work per time unit and compared with that obtained from the linear encoder. Subsequently, 20 additional subjects (10 training group vs. 10 control group) were assessed before and after completing a seven-week training programme designed to improve maximal power. Results showed that both assessment methods correlated highly in estimating mean power output at different loads (r range: 0.86–0.94; p?R²: 0.78). Good to excellent intra-tester (intraclass correlation coefficient (ICC) range: 0.81–0.97) and excellent inter-tester (ICC range: 0.96–0.99; coefficient of variation range: 2.4–4.1%) reliability was found for all loads. The W5″ Test was shown to be a valid, reliable and sensitive method for measuring mean power output during the bench press exercise in subjects who have previous resistance training experience.     

侗族情歌中的恋爱道德价值

侗族情歌具有恋爱自由、真诚高尚、忠贞专一、大胆追求、选择对象等恋爱道德价值。     

A simple classroom teaching technique to help students understand Michaelis-Menten kinetics

A new, simple classroom technique helps cell biology students understand principles of Michaelis-Menten enzyme kinetics. A student mimics the enzyme and the student's hand represents the enzyme's active site. The catalytic event is the transfer of marbles (substrate molecules) by hand from one plastic container to another. As predicted, increases in marble concentration increase the number of marbles transferred per unit time (initial rate, V(0)) until the turnover number becomes rate limiting and V(0) approaches the maximum velocity (V(max)), as described by the Michaelis-Menten equation. With this demonstration, students visualize an important concept: the turnover number is constant and independent of marble concentration. A student assessment of this exercise showed that it helped students visualize the turnover number and V(max) but not K(m), the marble concentration at which V(0) is one-half V(max). To address the concept of K(m), we use supplemental laboratory and lecture exercises. This exercise with plastic containers and marbles is equally suited to demonstrate the kinetics of carrier-mediated membrane transport. We conclude that this exercise helps students visualize the turnover number and V(max) and gives students important insights into the kinetic parameters used to characterize the catalytic activity of enzymes and membrane transporters.     

On the robustness of Riccati flows to complete model misspecification

Consider the continuous-time matrix Riccati operator Ricc$\left(Q\right)=AQ+Q{A}^{\prime }?QSQ+R$. In this work, we consider the robustness of this operator to direct perturbations of the matrices (A, R, S) and, in particular, the flow robustness of the corresponding Riccati differential equation. For a given class of perturbation, we show that the corresponding differential equation is well defined in the sense it is bounded above and below, it has a well-defined fixed point, and it converges to this fixed point exponentially fast. Moreover, the flow of the perturbed Riccati flow is close to the nominal Riccati flow when the perturbation is small; i.e. we prove a continuity-type condition in the size of the perturbation.