The effect of previous experience with information and communication technologies on performance in a Web-based learning program

The purpose of the present study was to analyze the influence of previous experience with information and communication technology (ICT) tools on performance in a Web-based course. Online activity was logged. Specifically, total activities carried out and five online activity measures were computed. One hundred and twenty university undergraduates participated in a Web-based course designed to train personnel trainers to apply ICT in training processes. Before starting the study, participants filled out a questionnaire designed to assess their frequency using ICT tools. At the end of the study, participants were asked to complete a questionnaire in order to collect information about their learning experience and their assessment of the virtual environment. Results suggest that previous experience significantly influences how people organize their online activities, but not the quantity of work carried out. Participants with more experience in the use of Internet tools, organize their work in the virtual classroom using less time and visiting fewer pages in each session. Previous experience did not influence the assessment of the virtual classroom as a training tool, since participants with both high and low previous experience gave extremely positive feedback on their Web-based learning experience.     

From lines to epipoles through planes in two views

This paper addresses the computation of the fundamental matrix between two views, when camera motion and 3D structure are unknown, but planar surfaces can be assumed. We use line features which are automatically matched in two steps. Firstly, with image based parameters, a set of matches are obtained to secondly compute homographies, which allows to reject wrong ones, and to grow good matches in a final stage. The inclusion of projective transformations gives much better results to match features with short computing overload. When two or more planes are observed, different homographies can be computed, segmenting simultaneously the corresponding planar surfaces. These can be used to obtain the fundamental matrix, which gives constraints for the whole scene. The results show that the global process is robust enough, turning out stable and useful to obtain matches and epipolar geometry from lines in man made environments.     

Controlled clinical assay in Clonidine, arginine aspartate, alpha-ketoglutarate of Ornithine and Ciproheptadine as growth stimulants in children with short stature

Eighty-one healthy prepubertal children of short stature, between two and twelve years of age, were divided into four homogeneous groups. Each group was treated with a placebo for one year and for a second year with one of the following drugs (double blind): clonidine (CI), arginine asprate (AA), ornithine alphaketoglutare (OKG), or cyproheptadine (Cp). CI and OKG did not better the standard deviation of height. AA and Cp did, but to no greater extent than the placebo. The growth rate did not change in any group. The ratio of bone age/chronological age was significantly higher at the end of the OKG year than at the end of the year with placebo, a difference that was not found in any other group. The prognosis of adult height (TW2) did not change in any group. The standard deviation of weight increased in all groups, both with the placebo and the various drugs, without significant differences between the groups. The CI caused frequent clinical side effects, including a reversible increase in transaminases in one child. The Cp stimulated hunger. The AA and OKG did not produce side-effects and the placebo increased appetite in 11% of the children. Somatomedin C was significantly higher after one year with Cp than after one year with the placebo, significantly higher after the placebo than after CI and AA and there was no difference between the treatment with the placebo and OKG. Growth hormone values in a 24 hour urine sample were so scattered that we do not consider them helpful.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extraction and characterization of soluble protein fractions from Phaseolus lunatus L seeds

Legume proteins as a potential source of valuable nutrients, are the object of several studies in order to obtain the best use. A basic knowledge becomes more important for those proteins from species not wholly utilized, before using them as food ingredients. The objective of this work was to determine several structural and nutritional characteristics of the protein fractions from Phaseolus lunatus, separated in different solvents. The relative amount of extraction for the albumins (ALB), globulins (GLB), prolamines (PRL), and glutelins (GLT) was 62.3, 34.8, 1.4 and 1.5%, respectively. The SDS-PAGE electrophoretic profile of both ALB and GLB, showed seven common bands in intervals from 10 to 95 kDa, and 14 to 99 kDa, respectively; the amino acids profile showed that PRL was the rich fraction in sulfurated amino acids (11.5 g/100 g protein); the content of lysine in the fraction of ALB was smaller than expected but the requirement of the FAO in the fractions of GLB and GLT was covered. In general, the fraction of GLB had the best balance of amino acids and digestibility (80%); however, it had a relationship of calculated protein efficiency ratio (C-PER) of 0.11, smaller than the ratio in ALB (0.97). The calorimetric analysis showed denatured temperatures around 90 degrees C for the ALB, GLB, and GLU fractions. The PRL fraction probably did not present a thermal transition because the proteins were denaturalized by the extraction conditions.     

Evaluation and optimization of an on-line admicelle-based extraction-liquid chromatography approach for the analysis of ionic organic compounds

Admicelles-based solid-phase extraction (SPE) was on-line coupled with liquid chromatography/electrospray ionization/ion trap mass spectrometry, and it was proposed for the extraction of ionic organic compounds based on the formation of surfactant-analyte ion pairs. The approach was illustrated by studying the preconcentration of quaternary ammonium herbicides (quats) on sodium dodecyl sulfate (SDS) admicelles produced on alumina. Optimization of the parameters affecting SPE were studied on the basis that admicelles are dynamic entities in equilibrium with the aqueous phase. Some general guidelines could be established for method development from the results obtained. Factors influencing on-line operation were elucidated. On-line regeneration of the sorbent in each run was easily achieved by disruption of SDS admicelles with methanol and posterior coating of the alumina with SDS. The recovery of quats from drinking water samples were found quantitative for paraquat, diquat, and difenzoquat and above to 70% for chlormequat and mepiquat. Concentration factors of about 250, using sample volumes of 50 mL, were achieved. The detection limits ranged from 10 to 30 ng/L. The approach developed permits compliance with the directives of the European Community for drinking waters (100 ng/L) and goes deeply into the basis of solid-phase extractions that use surfactant-coated mineral oxide as sorbents.     

Simple and stereoselective synthesis of sex pheromone of processionary mothThaumetopoea pityocampa (Denis and Schiff.)

A simple and stereoselective synthesis of (Z)-13-hexadecen-11-yn-1-yl acetate, the major component of the sex pheromone ofThaumetopoea pityocampa (Denis and Schiff.) is described. The procedure essentially involves formylation of a terminal acetylene to the corresponding aldehyde followed by a stereochemically controlled Wittig reaction, which has been studied under a variety of conditions.     

Reliability of the Beck Depression Inventory with older adults.

Examined the test–retest, split-half, and coefficient alpha reliability of the Beck Depression Inventory with a sample of 82 elderly community volunteers (mean age 69.9 yrs) and 77 depressed outpatients (mean age 67.8 yrs). All 3 indexes were reasonably high in the total sample and fell within the accepted range of reliability for a clinical screening instrument. As expected, internal consistency was lower when determined for the 2 separate samples. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Beck Depression Inventory and Research Diagnostic Criteria: Congruence in an Older Population.

This study examined the congruence between conventional cutoff scores on the Beck Depression Inventory (BDI) and selected diagnostic classifications of the Research Diagnostic Criteria in a sample of 102 elders seeking psychological treatment. Only 16.67% were misclassified by customary BDI cutoff scores. Minor Depressive Disorders were less clearly identified than Major Depressive Disorders or nondepressed status. Similar results were obtained in a second sample of elders not seeking treatment. Findings support the utility of the BDI as a screening instrument for identification of clinically depressed elders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and Characterization of Poly(carbonates) Derived from Diphenols That Contain Silicon or Germanium

Poly(carbonates) derived from diphenols that contain Si or Ge and bisphenol A bis(chloroformate) have been synthesized using phase-transfer conditions. The products were characterized by spectroscopic methods. Two phase-transfer catalysts and three molar ratios of NaOH/diphenol were used. The results were evaluated by the yields of product and their inherent viscosities. The data were compared with materials obtained without the catalyst and showed that the new synthetic technique was effective for the synthesis of these types of poly(carbonates). An increase in the concentration of NaOH and the phase-transfer catalysts increased the yields and _inh values compared to those obtained with stoichiometric quantities of NaOH. It is proposed that the differences in electronegativities of the heteroatoms in the diphenols are responsible for this behaviour.     

Surfactant to dye binding degree-based methodology for the determination of ionic amphiphilic compounds

A new analytical measurement parameter based on the effect of amphiphilic substances on the degree of binding of a surfactant to dye molecules, which induce the formation of surfactant premicellar aggregates, is presented. The theory for dye-surfactant intermolecular interactions in mixed surfactant systems, which assumes a mononuclear model for the formation of dye-induced premicellar aggregates, has been used to derive an expression that provides linear calibrations for the determination of amphiphilic compounds. The dye-surfactant interactions involved have been investigated, and the variables affecting the measurement analytical parameter have been discussed. The analytical applicability of the surfactant-dye binding degree method is demonstrated by quantifying major anionic surfactants at the nanograms-per-milliliter level and determining the total concentration of these amphiphilic substances in sewage samples (average recoveries ranged from 98 to 102%).