Consequences of experimental cortisol manipulations on the thermal biology of the checkered puffer (Sphoeroides testudineus) in laboratory and field environments.

Anthropogenic climate change is altering temperature regimes for coastal marine fishes. However, given that temperature changes will not occur in isolation of other stressors, it is necessary to explore the potential consequences of stress on the thermal tolerances and preferences of tropical marine fish in order to understand the thresholds for survival, and predict the associated coastal ecological consequences. In this study, we used exogenous cortisol injections to investigate the effects of a thermal challenge on checkered puffers (Sphoeroides testudineus) as a secondary stressor. There were no significant differences between control and cortisol-treated fish 48h following cortisol treatment for swimming ability (using a chase to exhaustion protocol), blood glucose concentrations or standard metabolic rate. In the lab, control and cortisol-treated puffers were exposed to ambient (29.1±1.5°C), ambient +5°C (heat shock) and ambient -5°C (cold shock) for 4h and to evaluate the consequences of abrupt temperature change on puff performance and blood physiology. Following cold shock, control fish exhibited increases in cortisol levels and weak 'puff' performance. Conversely, fish dosed with cortisol exhibited consistently high cortisol levels independent of thermal treatment, although there was a trend for an attenuated cortisol response in the cortisol-treated fish to the cold shock treatment. A 20-day complementary field study conducted in the puffer's natural habitat, a tidal creek in Eleuthera, The Bahamas, revealed that cortisol-injected fish selected significantly cooler temperatures, measured using accumulated thermal units, when compared to controls. These results, and particularly the discrepancies between consequences documented in the laboratory and the ecological trends observed in the field, highlight the need to establish the link between laboratory and field data to successfully develop management policies and conservation initiatives with regards to anthropogenic climate change.

Exploration for physicians of the mature minor doctrine.

The "mature minor doctrine" is the common-law rule that allows an adolescent who is mature to give consent for medical care. Ethical decisions regarding consent and confidentiality should be distinguished from legal requirements. Recent court decisions have altered the law, especially in regard to consent for refusal of life-sustaining treatment. There are statutory exceptions to the rule of parental consent regarding emergency care, sexually transmitted diseases, drug treatment, mental health care, pregnancy, contraception, and emancipation. A detailed analysis of the mature minor exception is presented, utilizing court case vignettes. There is minimal legal risk in allowing adolescents older than 14 years of age to give consent for treatments entailing small degrees of risk, when they can make adultlike decisions and demonstrate signs of maturity.