17 research outputs found
Characterization of a calcified intra-cardiac pseudocyst of the mitral valve by magnetic resonance imaging including T1 and T2 mapping
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Technical Note: A simple method for preparing reference slides of seed
Microhistological analysis has become the most commonly used and successful method for determining micromammal diets. However, this technique has a number of limitations, particularly when used on fecal samples where identification of some items is difficult. This method underestimates those nearly unrecognizable plant parts in the diet, such as seed, and overestimates easily identifiable parts, such as leaf epidermis. In this note we describe a simple technique that uses a macerating solution of 17.5% NaHCO3 for preparing reference slides of seeds. Advantages of the proposed method are discussed and compared with Jeffrey's technique.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202
Fluctuating asymmetry and developmental instability in Protoreaster nodosus (Chocolate Chip Sea Star) as a biomarker for environmental stress
Fluctuating asymmetry (FA), pertains to small and random departures from perfect symmetry of an organism's bilateral traits and has been used as a measurement of developmental instability and as a potential indicator of stress in populations. It measures the variations from symmetry of a symmetrical structure whose sides are said to be genetically identical, with similar history of gene activity and experiencing the same environment. Symmetries are potentially the basis for studies on FA. Hence, this study assessed the potential of FA as a reliable developmental instability and environmental stress indicator in five-fold dihedral symmetrical Protoreaster nodosus (Chocolate chip sea fish) from three (3) different sites (Linamon, Lanao del Norte; Initao, Misamis Oriental and Jasaan, Misamis Oriental). FA for each population from every site was measured for comparison. In this study, anatomical landmarks were subjected to Procrustes superimposition and Principal Component Analysis (PCA) using "Symmetry and Asymmetry in Geometric Data" (SAGE) program. Results showed highly significant FA and significant DA for population from Jasaan and Linamon where habitat disturbance due to anthropogenic activities were prevalent. Thus, experienced more stress compared to the other populations, suggesting that significant variation in size or left-right side of each individual could be a product of genotype-environment interaction. Moreover, insignificant FA and high DA was obtained from Initao (protected seascape area) which indicated that variation among individual genotypes and asymmetry in phenotypes is mostly induced by genetics under less stressful environment. Significant FA and increase FA present inability of species to buffer stress in its developmental pathways and have implications on species fitness. Hypothesis assumes that fluctuating asymmetry has costs, reflects the quality of individuals and the level of genetic and environmental stress experienced by individuals or populations during development. Here, FA proved to be efficient when applied to five-fold dihedral symmetrical organisms