Localization-delocalization transition of indirect excitons in lateral electrostatic lattices.

We study transport of indirect excitons in GaAs/AlGaAs coupled quantum wells in linear lattices created by laterally modulated gate voltage. The localization-delocalization transition for transport across the lattice was observed with reducing lattice amplitude or increasing exciton density. The exciton interaction energy at the transition is close to the lattice amplitude. These results are consistent with the model, which attributes the localization-delocalization transition to the interaction-induced percolation of the exciton gas through the external potential. We also discuss applications of the lattice potentials for estimating the strength of disorder and exciton interaction.

Oscillation frequency dependence of nonclassical rotation inertia of solid 4He.

The nonclassical rotational inertia fraction of the identical cylindrical solid 4He below 300 mK is studied at 496 and 1173 Hz by a double resonance torsional oscillator. Below 35 mK, the fractions are the same at sufficiently low rim velocities. Above 35 mK, the fraction is greater for the higher than the lower mode. The dissipation peak of the lower mode occurs at a temperature approximately 4 mK lower than that of the higher mode. The drive dependence of the two modes shows that the reduction of the fraction is characterized by critical velocity, not amplitude or acceleration.

Atypical eclampsia: a case report and review.

Up to one-third of cases of eclampsia occur in the postpartum period. Often there is evidence of preeclampsia, which alerts the physician to be prepared for the possibility of seizures. Eclampsia is an obstetrical emergency often requiring intensive care and monitoring. This reports the case of a 33-year-old gravida 5 para 4 abortus 1 who presented ten days postpartum with eclampsia. The patient had no history of hypertension, edema, or proteinuria during her prenatal visits or hospitalization, and has no history of preeclampsia or eclampsia in previous pregnancies. This case illustrates the rare occurrence of eclampsia late in the postpartum period and the equally rare onset of eclampsia without prior evidence of preeclampsia during her pregnancy. It is followed by a brief review of the relevant literature.

Update on the prevention and treatment of sexually transmitted diseases.

The Centers for Disease Control and Prevention updated its guidelines for the treatment of sexually transmitted diseases. The guidelines include the following information: recommendations for hepatitis A immunization and expanded indications for hepatitis B vaccination; updated diagnostic criteria for pelvic inflammatory disease and parenteral treatment regimens; information on two additional antiviral agents for the treatment of genital herpes; a recommendation for use of a single 1-g dose of azithromycin (Zithromax) to treat urethritis and chlamydial cervicitis; information on the use of quinolones in the treatment of gonococcal infections; information on podofilox and imiquimod, which are both patient-applied medications, in the treatment of noncervical human papillomavirus infection; updated guidelines for the prevention and detection of congenital syphilis; and information on how to prevent the spread of sexually transmitted diseases by educating patients about the importance of changing their sexual behaviors. To have a significant impact on the current rate of transmission of sexually transmitted diseases, family physicians should develop a plan to integrate the guidelines into their practices.