The decay τ-→K-KSντ has been studied using 430×106 e+e-→τ+τ- events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum ...of the K-KS system has been measured and the spectral function has been obtained. The measured branching fraction B(τ-→K-KSντ)=(0.739±0.011(stat)±0.020(syst))×10-3 is found to be in agreement with earlier measurements.
Vibrissal stimulation raises cerebral blood flow (CBF) in the ipsilateral spinal and principal sensory trigeminal nuclei and contralateral ventroposteromedial (VPM) thalamic nucleus and barrel ...cortex. To investigate possible roles of adenosine and nitric oxide (NO) in these increases, local CBF was determined during unilateral vibrissal stimulation in unanesthetized rats after adenosine receptor blockade with caffeine or NO synthase inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) or 7-nitroindazole (7-NI). Caffeine lowered baseline CBF in all structures but reduced the percent increase during stimulation only in the two trigeminal nuclei. L-NAME and 7-NI lowered baseline CBF but reduced the percent increase during stimulation only in the higher stations of this sensory pathway, i.e., L-NAME in the VPM nucleus and 7-NI in both the VPM nucleus and barrel cortex. Combinations of caffeine with 7-NI or L-NAME did not have additive effects, and none alone or in combination completely eliminated functional activation of CBF. These results suggest that caffeine-sensitive and NO-dependent mechanisms are involved but with different regional distributions, and neither fully accounts for the functional activation of CBF.
This study was aimed to compare fracture prevalence in oligoamenorrheic athletes (AA), eumenorrheic athletes (EA), and nonathletes (NA) and determine relationships with bone density, structure, and ...strength estimates.
One hundred seventy-five females (100 AA, 35 EA, and 40 NA) 14-25 yr old were studied. Lifetime fracture history was obtained through participant interviews. Areal bone mineral density (BMD) was assessed by DXA at the spine, hip, and whole body (WB). Bone structure was assessed by HRpQCT at the radius and tibia, and strength by finite element analysis.
AA, EA, and NA did not differ in age, sexual maturity, or height. AA had lower BMI, and older menarchal age than EA and NA (P ≤ 0.001). Bone mineral density Z-scores were lower in AA versus EA at the total hip, femoral neck, spine, and whole body (P ≤ 0.001). Lifetime fracture risk was higher in AA than EA and NA (47%, 25.7%, 12.5%; P ≤ 0.001), largely driven by stress fractures in AA versus EA and NA (32% vs 5.9% vs 0%). In AA, those who fractured had lower lumbar and WB BMD Z-scores, volumetric BMD (vBMD) of outer trabecular region in radius and tibia, and trabecular thickness of the radius (P ≤ 0.05). In AA, those who had two or more stress fractures had lower lumbar and WB BMD Z-scores, total cross-sectional area, trabecular vBMD, stiffness, and failure load at radius; and lower stiffness and failure load at tibia versus those with fewer than two stress fractures (P ≤ 0.05).
Weight-bearing athletic activity increases BMD but may increase stress fracture risk in those with menstrual dysfunction. Bone microarchitecture and strength differences are more pronounced in AA with multiple stress fractures. This is the first study to examine fractures in relation to bone structure in adolescent female athletes.
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