RESUMO
An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19} W/ cm^{2}. Highly charged gold ions with kinetic energies up to >200 MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.
Assuntos
Íons Pesados , Lasers , Modelos Teóricos , Aceleradores de Partículas , Ouro/química , TermodinâmicaRESUMO
Three mirror tracing experiments were conducted to investigate the connection between perception and motor behavior. In the first experiment, some subjects traced a hex-maze, other subjects traced a hex-maze after observing a model trace, others traced a hex-maze after reading instructions on mirror images, and others traced a hex-maze after having observed a model and heard the instructions. There were no significant differences between the groups' error scores, but their time scores differed significantly, although not always in the predicted direction. In Experiment 2, the subjects were to trace selected letters of the alphabet. Error scores for the second experiment did not differ much from those for the first experiment. In Experiment 3, the experimenter gave each subject commands for the correct directions of movement, using the subject's body as a frame-of-reference. There was little improvement in motor performance. These results suggest that the visual information presented in the mirror captured the subjects' attention and blocked their motor tracing program.
Assuntos
Atenção , Cognição , Dominância Cerebral , Orientação , Desempenho Psicomotor , Adulto , Aprendizagem por Discriminação , Humanos , Rememoração Mental , Reconhecimento Visual de Modelos , Resolução de ProblemasRESUMO
Multiple telephone follow-up interviews have been conducted for a number of years for boys with conduct disorders treated at the Saint Francis Academy. These follow-ups are done 2 years and 5 years after treatment completion and again after the boy's 24th birthday. An overall appropriate adult functioning (AAF) score is obtained for each boy contacted. Because the attrition rate is very low, these data provide an opportunity to investigate the stability of treatment effects over time. A substantial attempt was made to investigate the possibility that mean group changes in AAF over time might be due to differential attrition effects. Two separate analyses indicated that an attrition effect was not a major influence in AAF score changes. AAF was relatively stable between the 2- and 5-year follow-ups and showed some improvement.
Assuntos
Transtornos do Comportamento Infantil/reabilitação , Delinquência Juvenil/reabilitação , Desenvolvimento da Personalidade , Ajustamento Social , Adolescente , Adulto , Viés , Criança , Transtornos do Comportamento Infantil/diagnóstico , Transtornos do Comportamento Infantil/psicologia , Seguimentos , Humanos , Delinquência Juvenil/psicologia , Estudos Longitudinais , Masculino , Equipe de Assistência ao Paciente , Determinação da Personalidade/estatística & dados numéricos , Psicometria , Tratamento DomiciliarRESUMO
Boys admitted to a treatment facility do not always complete their treatment. This study analyzes the follow-up socialized coping of boys preponderantly classified as conduct disordered who were admitted to a residential treatment center. The boys were categorized into 10 different groups, only 1 of which consisted of those who actually completed treatment. The differences between groups and subsequent coping were fairly pronounced and highly significant. Further analysis indicated that very few of the group differences could be attributed to either age at admission or duration of treatment. Data analysis supported the hypothesis of treatment effectiveness in that boys who completed treatment did better in general than boys who did not, although those withdrawn by their parents did best of all. Furthermore, the rather pronounced differences among groups that failed to complete treatment raised certain methodological questions with regard to the practice of aggregating such groups in evaluation research.