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Nematodes are important: parasitic nematodes threaten the health of plants, animals and humans on a global scale; interstitial nematodes pervade sediment and soil ecosystems in overwhelming numbers; and Caenorhabditis elegans is a favourite experimental model system. A lack of clearly homologous characters and the absence of an informative fossil record(More)
Nematodes are known to be a useful system for studies of comparative development. Here we perform a molecular phylogenetic analysis to allow for the independent interpretation of the developmental and morphological changes observed among a selected set of nematode species. Our molecular phylogenetic analysis is based on coding regions of the genes for RNA(More)
A nematode, Scottnema lindsayae, is the dominant metazoan found in soils of the McMurdo Dry Valleys, Antarctica. The distribution of S. lindsayae is patchy within and between these dry valleys; nevertheless, it is unclear to what extent these populations are genetically isolated. We investigated genetic diversity in this nematode using nuclear and(More)
To effectively integrate DNA sequence analysis and classical nematode taxonomy, we must be able to obtain DNA sequences from formalin-fixed specimens. Microdissected sections of nematodes were removed from specimens fixed in formalin, using standard protocols and without destroying morphological features. The fixed sections provided sufficient template for(More)
Since the discovery of the ozone depletion in Antarctic and the globally declining trend of strato-spheric ozone concentration, public and scienti®c concern has been raised in the last decades. A very important consequence of this fact is the increased broadband and spectral UV radiation in the environment and the biological e€ects and heath risks that may(More)
The differential chromaticity thresholds of three color stimuli have been determined from metameric matches carried out during the cone-plateau period after photopigment bleaching. The results are compared with some recently published ones [E. Hita, L. Jiménez del Barco, and J. Romero, J. Opt. Soc. Am. A 3, 1203 (1986)] obtained under similar experimental(More)
OBJECTIVE To compare shear stability of simulated humeral lateral condylar fractures reduced with either a self-compressing pin or cortical bone screw. STUDY DESIGN In vitro biomechanical tests. SAMPLE POPULATION Bilateral cadaveric canine humeri (n=18) without evidence of elbow disease. METHODS Lateral condylar fracture was simulated by standardized(More)
Knowledge of ultraviolet radiation is necessary in different applications, in the absence of measurements, this radiometric ̄ux must be estimated from available parameters. To compute this ̄ux under all sky conditions one must consider the in ̄uence of clouds. Clouds are the largest modulators of the solar radiative ̄ux reaching the Earth's surface. The(More)