RESUMEN
In April 2010, crude oil was spilled from the Deepwater Horizon (DWH) oil platform for 87 days, coincident with the spawning season and recruitment of the oyster, Crassostrea virginica, in the Gulf of Mexico. Impacts of acute exposures to surface-collected DWH oil (HEWAF), dispersed oil (CEWAF) and dispersant alone (Corexit 9500A(®)) on planktonic larval stages of C. virginica (veliger, umbo and pediveliger) were tested in the laboratory. Exposures to HEWAF, CEWAF and dispersant were toxic to larvae impairing growth, settlement success and ultimately survival. Larval growth and settlement were reduced at concentrations of tPAH50 ranging from 1.7 to 106 µg L(-1) for HEWAF and 1.1-35 µg L(-1) for CEWAF, concentrations well within the range of water sampled during the DWH oil spill. Sublethal effects induced by oil and dispersant could have significant ecological implications on oyster populations and on the whole estuarine ecosystem.
Asunto(s)
Crassostrea/fisiología , Monitoreo del Ambiente , Contaminación por Petróleo , Petróleo/toxicidad , Tensoactivos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Larva/efectos de los fármacos , Larva/fisiología , Pruebas de ToxicidadRESUMEN
The explosion of the Deepwater Horizon (DWH) oil platform resulted in large amounts of crude oil and dispersant Corexit 9500A® released into the Gulf of Mexico and coincided with the spawning season of the oyster, Crassostrea virginica. The effects of exposing gametes and embryos of C. virginica to dispersant alone (Corexit), mechanically (HEWAF) and chemically dispersed (CEWAF) DWH oil were evaluated. Fertilization success and the morphological development, growth, and survival of larvae were assessed. Gamete exposure reduced fertilization (HEWAF: EC201h=1650µg tPAH50L(-1); CEWAF: EC201h=19.4µg tPAH50L(-1); Corexit: EC201h=6.9mgL(-1)). CEWAF and Corexit showed a similar toxicity on early life stages at equivalent nominal concentrations. Oysters exposed from gametes to CEWAF and Corexit experienced more deleterious effects than oysters exposed from embryos. Results suggest the presence of oil and dispersant during oyster spawning season may interfere with larval development and subsequent recruitment.
Asunto(s)
Crassostrea/efectos de los fármacos , Contaminación por Petróleo , Petróleo/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Crassostrea/embriología , Embrión no Mamífero/efectos de los fármacos , Monitoreo del Ambiente , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , México , Agua de Mar/química , Calidad del AguaRESUMEN
Thirty depressed and 30 nondepressed college students completed a social judgment task. Students initially received either positive, negative, or no preliminary feedback and were told that they could obtain more extended feedback about their performance at a cost of $.20 for each unit of feedback. As predicted, depressed students were willing to relinquish a greater amount of money to obtain self-relevant feedback. Additionally, depressed and nondepressed Ss were more motivated to obtain additional feedback after they had received positive or no preliminary feedback than after they had received negative preliminary feedback. Results support Rehm's (1977) description of a heightened need for external reassurance among depressed persons.
Asunto(s)
Trastorno Depresivo/psicología , Retroalimentación , Motivación , Adulto , Femenino , Humanos , Masculino , Refuerzo Verbal , AutoimagenRESUMEN
Utilization of positive and negative feedback was investigated in a sample of 20 depressed and 20 nondepressed psychiatric inpatients. Patients, selected on the basis of Minnesota Multiphasic Personality Inventory scores and clinical diagnoses, received primarily positive or negative feedback after completing a moral judgment task. Results suggest that depressed patients are likely to utilize positive, personally relevant information to enhance their low self-esteem, whereas nondepressed patients are more likely to counteract negative feedback that is inconsistent with their self-evaluations. The results fail to confirm the presence of memory deficits for positive feedback in depression, proposed by Kovacs and Beck (Am. J. Psychiatry, 135: 525-532, 1978), and are more consistent with the prediction of Mischel et al. (J. Consult. Clin. Psychiatry, 44: 92-103, 1976) that people tend to be cognitively biased toward success and toward perpetuating positive emotional states.
Asunto(s)
Trastornos de Adaptación/psicología , Trastornos Psicóticos Afectivos/psicología , Retroalimentación , Trastornos Psicóticos/psicología , Autoimagen , Trastornos de Adaptación/terapia , Adulto , Trastornos Psicóticos Afectivos/terapia , Femenino , Humanos , Masculino , MemoriaRESUMEN
Sixty psychiatric inpatients were assigned to one of three groups on the basis of F and K MMPI validity scales. Staff ratings of patient behavior and recorded incidents of "acting-out" behavior were obtained for patients with: (a) "plea for help" validity profiles, (b) hyper-defensive profiles, and (c) average profiles. Patients with "plea for help" profiles were perceived as "acting-out" more frequently and engendering more feelings of frustration than patients in the other groups. These patients account for 77% of the incidents of inappropriate, destructive behavior and 83% of the seclusions in the patients sampled. Although the "plea for help" profile is considered invalid in some scoring systems, results suggest that this validity profile may be useful in treatment planning.