RESUMEN
Southern elephant seals (SES) experience a 'catastrophic molt', a costly event characterized by the renewal of both hair and epidermis that requires high peripheral vascular circulation. Molting animals are therefore constrained by high metabolic heat loss and are thought to fast and remain on land. To examine the ability of individuals to balance the energetic constraints of molting on land we investigate the stomach temperature and movement patterns of molting female SES. We find that 79% of females swam and 61% ingested water or prey items, despite the cost of cold-water exposure while molting. This behavior was related to periods of warm and low wind conditions, and females that dived and ingested more often, lost less body mass. We conclude that the paradigm of fasting during the molt in this species, and the fitness consequences of this behavior should be reconsidered, especially in the context of a changing climate.
Asunto(s)
Muda , Phocidae , Femenino , Animales , Regulación de la Temperatura Corporal , Agua , Ingestión de AlimentosRESUMEN
Executive functions encompass various cognitive processes and are critical in novel or demanding driving situations. Our aim was to determine the role of impairments in specific executive functions (updating, flexibility, inhibition) on road performance in drivers with Parkinson's disease (PD), a condition commonly associated with early executive dysfunction. In this pilot study, 19 patients with mild to moderate PD and 21 healthy controls matched for age, education, and driving experience were tested using a neuropsychological battery assessing global cognitive abilities, updating (n-back task), flexibility (plus-minus task), and inhibition (Stroop test). Participants also underwent a 45-minute road test in which they were scored by a driving instructor and a second experimenter. To separate "at-risk" drivers from safe drivers, a composite driving indicator was calculated from the Test Ride for Investigating Practical Fitness to Drive score, the penalty score from the observation grid, and the number of safety interventions made by the driving instructor. Eight of the 40 drivers (all PD) were rated as "at risk." Measures of updating (the n-back task) and mental flexibility (the plus-minus task) predicted driving safety even after adjustment for group status, explaining 53% of the total variance. These 2 tests also discriminated between safe and "at-risk" drivers within the PD group. These findings, although preliminary, suggest that updating and mental flexibility are critical for safe driving in PD. Assessment batteries for driving fitness should probe different aspects of executive functions, specifically when evaluating drivers with PD.