Methodologies for the Participant Construction of Knowledge

Over the last few decades there have been increasingly rapid changes in all fields (economic, political, etc. ...) leading to new forms of education and research. During the 1990s we have been working on innovative forms of education and participant research. In this context, this article includes some reflections on specific experiences of the construction of collective knowledge carried out in several cities, mainly in Spain and Latin America. It focuses on concrete postgraduate course experiences and it shows some innovative ways of collaborative relations between University, Public Administrations, and Social Organizations. The main theoretical and methodological principles of these experiences are also developed. On the other hand, we have been developing a network with some Latin partners on both sides of the ocean and we have recently made contacts with partners from English-speaking countries. We hope this article will contribute to building new bridges and communications on participant and instituent forms of knowledge construction.     

Stimulation of pyruvate carboxylation by gastric secretagogues

Pyruvate carboxylation was stimulated by 2 gastric secretagogues, histamine and dibutyryl cyclic AMP, and by butyrate. Thiocyanate, an inhibitor of acid secretion, produced a slight decrease. Avidin significantly reduced acid secretion and this effect was overcome by biotin and oxalacetate. The results suggest that carboxylation of pyruvate is one of the reactions controlling oxidative metabolism and acid secretion in toad gastric mucosa.     

Antimicrobial effect of bis-quaternary ammonium salts derived from 1,3-propanediamine.

Antimicrobial activity of bis-quaternary ammonium salts derived from 1,3-propanediamine and 1,3-diamino-2-propanol is described. Effect of the length of alkyl chain and the substitution in the connecting chain on this activity was studied.     

cAMP in spermatozoa taken from different segments of rat epididymis.

Experimental evidence conclusively indicates that the epididymis is under endocrine control and plays an active role in the process of spermatic maturation.     

Computational algorithms for simulating the grain structure formed on steel billets using cellular automaton and chaos theories

The development of some computational algorithms based on cellular automaton was described to simulate the structures formed during the solidification of steel products. The algorithms described take results from the steel thermal behavior and heat removal previously calculated using a simulator developed by present authors in a previous work. Stored time is used for displaying the steel transition from liquid to mushy and solid. And it is also used to command computational subroutines that reproduce nucleation and grain growth. These routines are logically programmed using the programming language C++ and are based on a simultaneous solution of numerical methods (stochastic and deterministic) to create a graphical representation of different grain structures formed. The grain structure obtained is displayed on the computer screen using a graphical user interface (GUI). The chaos theory and random generation numbers are included in the algorithms to simulate the heterogeneity of grain sizes and morphologies.     

含有改性混凝土叠合层的T形梁抗裂性能研究

基于8根混凝土倒T形叠合梁受弯试验,研究了钢筋钢纤维自应力混凝土做加固材料层二次浇注到待加固混凝土T形梁,从而形成的叠合梁在负弯矩区的抗裂性能.试验结果表明,仅占叠合梁高13.9%的叠合层将梁的开裂弯矩提高44.9%.同时根据已有理论模型,推导了自应力混凝土叠合T梁后加自应力的求法和负弯矩区正截面抗裂计算公式,其计算结果与试验结果比较吻合.