Quantum theory of dissipation of a harmonic oscillator coupled to a nonequilibrium bath; Wigner-Weisskopf decay and physical spectra

We extend the quantum theory of dissipation in the context of system-reservoir model, where the reservoir in question is kept in a nonequilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein's relations have been pointed out. We show that the Wigner-Weisskopf decay of the system mode results in a rate constant which depending on the relaxation of nonequilibrium bath is dynamically modified. We also calculate the time-dependent spectra of a cavity mode with a suitable gain when the cavity is kept in contact with a nonequilibrium bath.Comment: Plain Latex, 28 pages, 2 PS figure

Serum testosterone levels of HbSS (sickle cell disease) male subjects in Lagos, Nigeria

<p>Abstract</p> <p>Background</p> <p>Infertility is a major problem in sickle cell disease patients, especially in males. In addition to low serum testosterone, other abnormalities involving the accessory sex organs, such as the seminal vesicles and the prostate gland, as well as marked decrease in ejaculate volume may be observed in male HbSS patients. Hence, the need to study the role of sex hormones as a cause of infertility in male HbSS patients.</p> <p>Methods</p> <p>An unmatched case-control study was performed using seventy-five consenting subjects from Lagos University Teaching Hospital. These included 47 patients with haemoglobin phenotype SS from the Sickle cell clinic and 28 volunteered medical students and members of staff with haemoglobin phenotype AA. Demographic data were obtained using a self-administered questionnaire. A total of 5 mls of blood was collected from each subject between 9.00 am & 11.am, and assayed for serum testosterone concentration.</p> <p>Results</p> <p>The concentrations of serum testosterone in HbSS patients ranged from 0.2 to 4.3 ng/ml with a mean of 1.28 ± 0.72 ng/ml whilst the values in HbAA controls ranged from 1.2 to 6.9 ng/ml with a mean of 2.63 ± 1.04 ng/ml. Seven (25.0%) of the 28 controls had serum testosterone concentration lower than the quoted reference (normal) range whereas 44 (93.6%) of the 47 HbSS subjects had serum testosterone concentration lower than the reference range.</p> <p>Conclusion</p> <p>Overall, subjects with HbSS have significantly lower mean serum testosterone than HbAA controls.</p

Usage of spatial scales for the categorization of faces, objects, and scenes

The role of spatial scales (or spatial frequencies) in the processing of faces, objects, and scenes has recently seen a surge of research activity. In this review, we will critically examine two main theories of scale usage. The fixed theory proposes that spatial scales are used in a fixed, perceptually determined order (coarse to fine). The flexible theory suggests instead that usage of spatial scales is flexible, depending on the requirements of visual information for the categorization task at hand. The implications of the theories are examined for face, object, and scene categorization, attention, perception, and representation