Influence of incubation temperature on morphology and locomotion performance of Leatherback (<i>Dermochelys coriacea</i>) hatchlings

The journey of Leatherback (Dermochelys coriacea (Vandelli, 1761)) hatchlings from nest to the sea is a vulnerable life-history stage. Studies have shown that nest incubation temperatures influence hatchling morphology and locomotor performance, which may affect hatchling fitness. We obtained incubation temperature profiles from 16 Leatherback nests in Tobago, West Indies, during the 2008 nesting season (March-June). There was significant variation among mean nest incubation temperatures, which had a significant influence on hatchling morphology. Using principal components analysis, we determined the morphological traits that explained the most variation among hatchlings, which allowed investigation of the relationship between hatchling morphology and terrestrial locomotion speed. Hatchlings with a narrower carapace width and longer flipper reach (produced at lower incubation temperatures) had significantly faster terrestrial speed and total run time than those with opposite characteristics (produced at higher incubation temperatures). Our results demonstrate that lower incubation temperatures produce hatchlings with traits that are significantly advantageous to terrestrial locomotion. These findings suggest that nest incubation temperature is important in determining hatchling fitness, as nest incubation temperature significantly influences hatchling morphology and locomotor capabilities. This study supplements related findings in Green Turtles (Chelonia mydas (L., 1758)), but also illustrates some unique features in Leatherbacks

Epidemiological and genetic study of exertional rhabdomyolysis in a Warmblood horse family in Switzerland

REASONS FOR PERFORMING STUDY: Exertional rhabdomyolysis (ER) and its familial basis in Warmblood horses is incompletely understood. OBJECTIVES: To describe the case details, clinical signs and management of ER-affected Warmblood horses from a family with a high prevalence of ER, to determine if histopathological signs of polysaccharide storage myopathy (PSSM) and the glycogen synthase (GYS1) mutation are associated with ER in this family, and to investigate potential risk factors for development of ER. METHODS: A family consisting of a sire with ER and 71 of his descendants was investigated. History of episodes of ER, husbandry, feeding and use was assessed by interviewing horse owners using a standardised questionnaire. All horses were genotyped for GYS1. In 10 ER-affected horses, muscle histopathology was evaluated. RESULTS: Signs of ER were reported in 39% of horses and 51% of the entire family possessed the GYS1 mutation. Horses possessing the GYS1 mutation had a 7.1-times increased risk for developing ER compared to those with the normal genotype (95% confidence interval [CI] 2.37-21.23, P = 0.0005). All muscle samples from horses in the family with ER showed polysaccharide accumulation typical for PSSM, amylase-resistant in 9/10 cases. There was evidence (odds ratio 5.6, CI 1.00-31.32, P = 0.05) that fat or oil feeding improved clinical signs of ER. No other effects of environmental factors associated with clinical signs of ER were identified. CONCLUSION AND POTENTIAL RELEVANCE: PSSM associated with the GYS1 mutation is one identifiable cause of ER in Warmblood horses. Signs of ER are not always manifest in GYS1 positive horses and there are also other causes for ER in Warmblood horses. Breeding animals with the GYS1 mutation results in a high prevalence of ER due to its dominant mode of inheritance

Improving forest type discrimination with mixed lifeform classes using fuzzy classification thresholds informed by field observations

This paper presents a three-stage methodology to mitigate uncertainty in forest lifeform classification using a case study in the mixed hardwood-conifer forest of Massachusetts, USA. First, two fuzzy membership surfaces representing the proportion of conifer and hardwood lifeform dominance were created using a supervised multilayer perceptron neural network algorithm. Second, an index of lifeform membership was generated using a ratio of the membership surfaces of conifer and hardwood forest. Lastly, this index was thresholded using field measurements of forest lifeform proportion to delineate pure conifer, mixed conifer-hardwood, and pure hardwood categories. This methodology produced a map of forest lifeform with 94% overall accuracy (kappa 0.88 for hardwood, 0.97 for conifer, and 0.97 for mixed), an improvement of 10% over a map generated using a top-down method using mixed forest training sites. Per-class accuracies increased approximately 5% for both the pure hardwood class, 26% for the pure conifer class, and 16% for the mixed class. The improvement in map accuracy was due to improved spectral discrimination of lifeforms, which results in a more geographically plausible map. © 2010 CASI