534 research outputs found
Soviet Musicology and Contemporary Practice: A Latvian Icon Revisited
When the Baltic states of Lithuania, Latvia, and Estonia were annexed by the Soviet Union at the end of World War II, their new leaders brought not only collectivization, deportations, and myriad other familiar terrors of the Soviet system
STRESS-STRAIN CHARACTERISTICS OF MATERIALS AT HIGH STRAIN RATES. PART IV. EXPERIMENTAL AND THEORETICAL ANALYSIS OF PLASTIC IMPACTS ON SHORT CYLINDERS
The effects of strain rate on the stress-strain characteristics of copper and lead were studied by measuring both stress and strain as functions of time using short cylindrical specimens supported at one end on a modified Hopkinson pressure bar and impacted at the other end by a steel projectile. Corresponding stresses and strains were computed according to an elementary nonstrain-rate theory (sometimes referred to as the von Karman theory) in which the dynamic stress-strain curve is assumed to be the same as the static stress- strain curve. Stresses and strains were also computed according to an elementary strain-rate theory (sometimes referred to as the Malvern theory) in which the dynamic stress may exceed the static stress for a given strain by an amount which depends upon the strain rate. It was found that the predictions of the nonstrain- rate theory agreed with measured values only for low impact velocities and for points at least two diameters from the impact end of the specimen. By proper choice of the flow or relaxation constant in the elementary strain-rate theory, measured and computed values of strain, or of stress, but not both simultaneously, could be brought into agreement. In the more general exponentialtype, strain-rate law, two independent parameters appear. Presumably with two constants to adjust, this theory could be made to correctly predict both stresses and strains for the conditions under which the tests were performed. If this procedure forces the theory to account for variations which are actually caused by lateral inertia and shear, erroneous conclusions regarding the properties of the material will be drawn. Further study of the effects of shear and lateral inentia is indicated. (auth
Editors' Introduction
The nine essays published in this volume derive from papers presented at the 39th World Conference of the International Council for Traditional Music (ICTM) held in Vienna, Austria, in July 2007
River Otter in Arkansas III. Characteristics of Otter Latrines and Their Distribution Along Beaver-Inhabited Watercourses in Southwest Arkansas
Forty-one river otter (Lutra canadensis) fecal deposit (latrine) sites were located during April 1983 through March 1984 along beaver (Castor canadensis) inhabited watercourses in Clark, Nevada, and Ouachita counties, Arkansas. Latrine sizes ranged from 64 cm² to 5.01 m² (x-bar=0.30 m²; S.D. =0.88), and contained 2 to 78 scats per latrine (x-bar=9.2; S.D. = 13.8). The most common sites for latrines included elevated leaf or moss covered banks (51.2%), beaver lodges or bank dens (17.1 %), and beaver scent mounds (12.2%). Other latrine sites included felled logs over open water, bare soil along elevated banks, and exposed sandbars. Otter presence fluctuated seasonally in beaver areas, with the periods of greatest occurrence being early summer and late winter
River Otter in Arkansas: II. Indications of a Beaver-Facilitated Commensal Relationship
Dam building activities of beaver (Castor canadensis) create ponds that apparently augment habitat available to otter (Lutra canadensis). This paper considers possible effects of beaver activity and pond formation on distribution and populations of otter in Arkansas. Literature synthesis and analysis of harvest records were used to investigate the suspected relationship
Age and Prostate-Specific Antigen Level Prior to Diagnosis Predict Risk of Death from Prostate Cancer.
A single early prostate-specific antigen (PSA) level has been correlated with a higher likelihood of prostate cancer diagnosis and death in younger men. PSA testing in older men has been considered of limited utility. We evaluated prostate cancer death in relation to age and PSA level immediately prior to prostate cancer diagnosis. Using the Veterans Affairs database, we identified 230,081 men aged 50-89 years diagnosed with prostate cancer and at least one prior PSA test between 1999 and 2009. Prostate cancer-specific death over time was calculated for patients stratified by age group (e.g., 50-59 years, through 80-89 years) and PSA range at diagnosis (10 ranges) using Kaplan-Meier methods. Risk of 10-year prostate cancer mortality across age and PSA was compared using log-rank tests with a Bonferroni adjustment for multiple testing. 10.5% of men diagnosed with prostate cancer died of cancer during the 10-year study period (mean follow-up = 3.7 years). Higher PSA values prior to diagnosis predict a higher risk of death in all age groups (p < 0.0001). Within the same PSA range, older age groups are at increased risk for death from prostate cancer (p < 0.0001). For PSA of 7-10 ng/mL, cancer-specific death, 10 years after diagnosis, increased from 7% for age 50-59 years to 51% for age 80-89 years. Men older than 70 years are more likely to die of prostate cancer at any PSA level than younger men, suggesting prostate cancer remains a significant problem among older men (even those aged 80+) and deserves additional study
Effect of Level of Urology Training on Gleason Score and Prostate Volume Estimation Agreement between Transrectal Ultrasound Guided Biopsy and Radical Prostatectomy Specimen
Introduction Transrectal ultrasound guided prostate biopsy may be performed by operators with various levels of training. Little is known about the impact of training level on biopsy results. We evaluated the effect of training level on the accuracy of transrectal ultrasound guided prostate biopsy findings. Methods We retrospectively reviewed 500 consecutive patients who underwent transrectal ultrasound guided prostate biopsy and subsequent radical prostatectomy. Transrectal ultrasound operators were stratified based on level of training as junior, senior, chief, fellow or staff. Linear regression was performed to analyze the effect of training level on volume estimates. A weighted Kappa statistic evaluated agreement between biopsy and pathological Gleason scores while an adjusted cumulative logistic regression model analyzed the effects of training level. Results A total of 482 patients were included in the final analysis. Transrectal ultrasound guided biopsy was performed by staff in 78 (16%) patients, by fellows in 18 (4%), chief residents in 48 (10%), senior residents in 126 (26%) and junior residents in 212 (44%). There was no significant difference between transrectal ultrasound and radical prostatectomy specimen volume estimates among the training levels. Level of training was not significantly associated with pathological features, including Gleason score, primary Gleason grade, highest single Gleason grade and estimated tumor volume. Study limitations include the retrospective design and the variability among members of the same group. Conclusions Agreement between biopsy and pathological Gleason scores is high for all levels of training. Training level has no impact on prostate volume estimations or the prediction of pathological features
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