New Experimental Limits on Macroscopic Forces Below 100 Microns

Results of an experimental search for new macroscopic forces with Yukawa range between 5 and 500 microns are presented. The experiment uses 1 kHz mechanical oscillators as test masses with a stiff conducting shield between them to suppress backgrounds. No signal is observed above the instrumental thermal noise after 22 hours of integration time. These results provide the strongest limits to date between 10 and 100 microns, improve on previous limits by as much as three orders of magnitude, and rule out half of the remaining parameter space for predictions of string-inspired models with low-energy supersymmetry breaking. New forces of four times gravitational strength or greater are excluded at the 95% confidence level for interaction ranges between 200 and 500 microns.Comment: 25 Pages, 7 Figures: Minor Correction

Cognitive performance in healthy women during induced hypogonadism and ovarian steroid addback

BACKGROUND: Gynecology clinic-based studies have consistently demonstrated that induced hypogonadism is accompanied by a decline in cognitive test performance. However, a recent study in healthy asymptomatic controls observed that neither induced hypogonadism nor estradiol replacement influenced cognitive performance. Thus the effects of induced hypogonadism on cognition might not be uniformly experienced across individual women. Moreover, discrepancies in the effects of hypogonadism on cognition also could suggest the existence of specific risk phenotypes that predict a woman’s symptomatic experience during the menopause. In this study, we examined the effects of induced hypogonadism and ovarian steroid replacement on cognitive performance in healthy premenopausal women. METHODS: Ovarian suppression was induced with a GnRH agonist (Lupron) and then physiologic levels of estradiol and progesterone were re-introduced in 23 women. Cognitive tests were administered during each hormone condition. To evaluate possible practice effects arising during repeated testing, an identical battery of tests was administered at the same time intervals in 11 untreated women. RESULTS: With the exception of an improved performance on mental rotation during estradiol, we observed no significant effects of estradiol or progesterone on measures of attention, concentration, or memory compared with hypogonadism. CONCLUSIONS: In contrast to studies in which a decline in cognitive performance was observed in women receiving ovarian suppression therapy for an underlying gynecologic condition, we confirm a prior report demonstrating that short term changes in gonadal steroids have a limited effect on cognition in young, healthy, women. Differences in the clinical characteristics of the women receiving GnRH agonists could predict a risk for ovarian steroid-related changes in cognitive performance during induced, and possibly, natural menopause. Key Words: estradiol, hypogonadism, progesterone, cognition