Testing for Validity and Reliability in Cross-Cultural Research

A set of procedures is offered for assessing interraler reliability and certain aspects of validity of codes in cross-cultural studies. The method assumes that at least two independent raters have coded more than one trait. Each trait coded by one rater is correlated with each trait coded by a second, and all the codings by a single rater are intercorrelated with each other. The results are presented in a multitrait-multi-rater matrix. From this matrix it is possible to determine the interrater reliability and discriminant validity of trails in addition to a higher order concept based on pairs of traits.     

A random fatigue of mechanize titanium abutment studied with Markoff chain and stochastic finite element formulation

To measure fatigue in dental implants and in its components, it is necessary to use a probabilistic analysis since the randomness in the output depends on a number of parameters (such as fatigue properties of titanium and applied loads, unknown beforehand as they depend on mastication habits). The purpose is to apply a probabilistic approximation in order to predict fatigue life, taking into account the randomness of variables. More accuracy on the results has been obtained by taking into account different load blocks with different amplitudes, as happens with bite forces during the day and allowing us to know how effects have different type of bruxism on the piece analysed.     

GABAB Receptor-Mediated Effects in Synaptosomes of Lethargic (lh/lh) Mice

Abstract: Previously, we have shown a significant increase in number of GABA_B receptor binding sites in neocortex and thalamus of lethargic ( lh/lh ) mice, a mutant strain exhibiting absence seizures. This study was performed to test our hypothesis that presynaptic GABA_B receptors would inhibit [³H]GABA release to a greater degree in lh/lh mice compared with their nonepileptic littermates (designated +/+). Synaptosomes isolated from neocortex and thalamus of age-matched male lh/lh and +/+ mice were similar in uptake of [³H]GABA. In the neocortical preparation, baclofen dose-dependently inhibited [³H]GABA release evoked by 12 m M KCl, an effect mediated by GABA_B receptors. The maximal inhibition ( I _max) value was significantly greater (80%) in lh/lh than +/+ mice, whereas the IC₅₀ (3 µ M ) was unchanged. In the thalamic preparation, the effect of baclofen (50 µ M ) was 58% less robust in lh/lh mice. Other effects mediated by GABA_B receptors (inhibitions in Ca²⁺ uptake and cyclic AMP formation) were also significantly reduced in thalamic synaptosomes from lh/lh mice. These data suggest a greater presynaptic GABA_B receptor-mediated effect in neocortex and a reduced effect in thalamic nuclei of lh/lh mice. It is possible that selective effects of presynaptic GABA_B receptors on GABA release in neocortex and thalamic nuclei of lh/lh mice may contribute to mechanisms underlying absence seizures.     

On the absence of correlation between cyanide-resistant respiration and cytochrome d content in bacteria

The regularity of appearance of cyanide-resistant respiration and cytochrome d in various bacteria as well as the relationship between the degree of resistance of respiration to cyanide and cytochrome d content was studied. Bacteria able to synthesize cyanide-resistant respiration were shown to appear during transition of culture to the stationary phase of growth caused by the exhaustion of carbon source. No regulatory of appearance of cytochrome d was observed. There is no correlation between the degree of resistance to cyanide and cytochrome d content. It was concluded that the cyanide-resistant respiration of bacteria and eukaryotic microorganisms may be associated with the functioning of a non-cytochrome nature oxidase.     

Reliability of surface electromyography for the gluteus medius muscle during gait in people with and without chronic nonspecific low back pain

The purpose of this study was to determine the intratester reliability of surface electromyography (EMG) assessment of the gluteus medius muscle in healthy people and people with chronic nonspecific low back pain (CNLBP) during barefoot walking. Gluteus medius muscle activity was measured twice in 40 people without and 30 people with CNLBP approximately 7 days apart. Walking gluteus medius muscle activity was normalised to maximal voluntary isometric contractions during side-lying hip abduction with manual resistance. Good intratester reliability (ICC > 0.75) was found for mean, peak, and peak to peak amplitude for healthy people. Only mean amplitude demonstrated good intratester reliability in those with CNLBP. Peak amplitude and peak to peak amplitude of the gluteus medius muscle of those with CNLBP, and the time of peak amplitude in both groups, demonstrated moderate reliability (ICC ranged from 0.50 to 0.58). Moderate to large standard error of measurement and minimal detectable change values were reported for outcome measurements. These results suggest that potentially large levels of random error can occur between sessions. Future research can build on this study for those with pathology and attempt to establish change values for EMG that are clinically meaningful.