University of Lleida

About: University of Lleida is a education organization based out in Lleida, Spain. It is known for research contribution in the topics: Population & Pregnancy. The organization has 2939 authors who have published 5853 publications receiving 148417 citations. The organization is also known as: Escola Superior Politècnica & Universitat de Lleida.

Reduction of pectinesterase activity in a commercial enzyme preparation by pulsed electric fields: comparison of inactivation kinetic models

Abstract: The inactivation of pectinesterase (PE) in a commercial enzyme preparation (CEP) under high intensity pulsed electric fields (HIPEF) was studied. After desalting and water dilution of the raw CEP, samples were exposed to exponentially decay waveform pulses for up to 463 µs at electric field intensities ranging from 19 to 38 kV cm−1. Pulses were applied in monopolar mode. Experimental data were fitted to a first-order kinetic model as well as to models based on Fermi, Hulsheger or Weibull equations to describe PE inactivation kinetics. Characteristic parameters for each model were calculated. Relationships between some of the parameters and process variables were obtained. The Weibull model yielded the best accuracy factor. The relationship between residual PE and input of electrical energy density was found to be that of exponential decay. Copyright © 2005 Society of Chemical Industry

On the Relatedness and Nestedness of Constraints

Abstract: The purpose of this opinion paper is providing a platform for explaining and discussing the relatedness and nestedness of constraints on the basis of four claims: (a) task constraints are distributed between the person and the environment and hence are relational variables, (b) being relational, task constraints are also emergent properties of the organism/environment system, (c) constraints are nested in timescales, and (d) a vast set of constraints are correlated through circular causality. Theoretical implications for improving the understanding of the constraints-led approach and practical applications for enhancing the manipulation of constraints in learning and training settings are proposed.

Kinesics and proxemics communication of expert and novice PE teachers

Abstract: The aim of the study is to analyse the sequential paraverbal communication used while teaching by expert and novice PE teachers. Four expert and four novice teachers were observed using a coding scheme of paraverbal behavior. The detection of temporal patterns using Theme v.5 enabled sequential analyses of paraverbal behaviour. The results indicate that compared to expert teachers, novice teachers used a greater number of gestures and did not always make effective use of the teaching space. Their gestures were also less qualitative in nature as they did not take full advantage of the communicative possibilities offered by some of the gestures analysed.