RESUMO
The second harmonic of the laser light (2omega(0)) is observed on the rear side of thick solid targets irradiated by a laser beam at relativistic intensities. This emission is explained by the acceleration by the laser pulse in front of the target of short bunches of electrons separated by the period (or half the period) of the laser light. When reaching the rear side of the target, these electron bunches emit coherent transition radiation at 2omega(0). The observations indicate that, in our conditions, the minimum fraction of the laser energy transferred to these electron bunches is of the order of 1%.
RESUMO
The high rates of adolescent sexual activity, often with adverse medical and social outcomes among minority females, prompted us to survey 160 girls between the ages of 13 and 18 concerning their knowledge of reproductive health terms, anatomy, and body functions. All were patients in a clinic in an inner-city hospital. We hypothesized that adolescents who were older, sexually active, and/or had received formal sex education would be better informed. We used a two-part, self-administered questionnaire. The first part focused on definitions of nine common medical and reproductive health terms; the second focused on definitions of unlabeled anatomic drawings of male and female genitourinary systems. The subjects' responses revealed their lack of information as well as a great deal of misinformation. No statistical differences in knowledge were found related to age, sexual activity status, or formal sex education. Many patients knew only nontechnical and slang terms and did not understand medical terms used by physicians in the clinic. Clinicians should not assume similar patients (minority and poor) know or understand their terminology and should use simple and, if necessary, explicit vocabulary.
