824 research outputs found
A Mad Stone
Here and there is found a man possessing a pebble for which he claims the remarkable power of preventing hydrophobia when applied to the wound made by a mad dog. We have been unable to find any record of a scientific examination of a mad stone or a scientific test of its properties. This may be partly accounted for by the rarity of the stone, and the high esteem in which they are held by their owners. A popular idea is that they are formed by accretion in a deer\u27s stomach
Bottom interaction of low-frequency acoustic signals at small grazing angles in the deep ocean
Also published as: Journal of the Acoustical Society of America 69 (1981): 84-94The results of a deep-ocean bottom interaction experiment are presented in which the effects of both bottom
refraction and subbottom reflection were observed. Data were obtained in the Hatteras Abyssal Plain using a
deep towed 220-Hz pulsed cw source and two receivers anchored near the bottom. For ranges between 1 and
6 km, corresponding to bottom grazing angles less than 13°, the quadrature components of the received
signals were recorded digitally. The observed amplitude shows a strong spatial interference pattern which is
composed of the direct and bottom interacting arrivals. It is shown that for small source-receiver separations,
the bottom return is dominated by a strong subbollom reflection. With increasing separation, this arrival
evolves into a refracted arrival due to the presence of a positive sound-speed gradient in the sediment
overlying the subbottom. Because of the gradient, a caustic is formed, and corresponding high intensity
regions are observed in the data at the expected ranges. Values of sediment layer thickness, sound-speed
gradient, and sound-speed drop at the water-bollom interface are obtained from best fits to the data using ray
theory, normal mode theory, and the parabolic equation method. These values are consistent with those
obtained in nearby locations by other workers. The success of the parabolic equation method indicates that at
small grazing angles, the bottom interaction process may be modeled as a propagation process combined with
the effect of a perfect, soft subbollom reflector. A value of sediment attenuation, 0.0015 dB/mat 220Hz, is
also inferred from the data and is among the lowest values reported to date in the literature.Prepared for the Office of Naval Research under Contract
N00014-77-C-0196 administered through NORD
Acupuncture as Treatment of Hot Flashes and the Possible Role of Calcitonin Gene-Related Peptide
The mechanisms behind hot flashes in menopausal women are not fully understood. The flashes in women are probably preceded by and actually initiated by a sudden downward shift in the set point for the core body temperature in the thermoregulatory center that is affected by sex steroids, β-endorphins, and other central neurotransmitters. Treatments that influence these factors may be expected to reduce hot flashes. Since therapy with sex steroids for hot flashes has appeared to cause a number of side effects and risks and women with hot flashes and breast cancer as well as men with prostate cancer and hot flashes are prevented from sex steroid therapy there is a great need for alternative therapies. Acupuncture affecting the opioid system has been suggested as an alternative treatment option for hot flashes in menopausal women and castrated men. The heat loss during hot flashes may be mediated by the potent vasodilator and sweat gland activator calcitonin gene-related peptide (CGRP) the concentration of which increases in plasma during flashes in menopausal women and, according to one study, in castrated men with flushes. There is also evidence for connections between the opioid system and the release of CGRP. In this paper we discuss acupuncture as a treatment alternative for hot flashes and the role of CGRP in this context
KINETIC, SPATIAL, AND TEMPORAL ASSESSENT OF OVERSPEED TOWING WITH ELASTIC TUBING
Subjects (N = 15) performed sprints over force platforms in a normal condition and in three overspeed conditions of differing elastic tube stretch length. Kinetic and kinematic data were derived. A 3 x 4 RM ANOVA was used to analyze the results. The horizontal and vertical ground reaction force (GRF), and the ratio of horizontal to vertical GRF did not differ among conditions (p ˃ 0.05). However, ground contact time was 8.3% to 10.4% shorter, time between steps was 1.4% to 2.7% lower, distance between steps was up to 1.2% greater, and velocity was 3.7% higher in some overspeed towing conditions compared to the normal condition (p ≤ 0.05). Longer tube conditions were more optimal in most cases. Compared to normal running, overspeed towing results in increased sprinting velocity despite no differences in horizontal or vertical kinetics compared to normal running
BIOMECHANICAL ANALYSIS OF TIRE FLIPPING WITH TIRES OF DIFFERENT MASSES AND THEIR POTENTIAL SPECIFICITY TO SPRINTING
This study compared the kinetics of tire flipping with different mass tires and sprinting to evaluate the potential specificity of this training stimulus. Subjects (N=15) performed tire flips with a 54.3 kg tire, a 102.1 kg tire, and sprinted on two large force platforms. Dependent variables included peak horizontal ground reaction force (HGRF), peak vertical GRF (VGRF), horizontal to vertical GRF ratio (H:V), and rate of vertical GRF development (VRFD). A RM ANOVA was used to analyze the data. Significant main effects were found for all dependent variables (p ≤ 0.03). Post-hoc analysis showed that the tires were different (p ≤ 0.04) for all dependent variables except for VRFD (p = 0.99). Post-hoc analysis showed that the 54.3 kg tire was more similar to the kinetics of sprinting for HGRF, VGRF, and H:V. Only tire flipping with a lighter tire was similar to key kinetic parameters of sprinting
IMET shipboard systems, operations and software user manual
This report has two parts. The first is a copy of the Operations and Software User Manual prepared for use with the IMET
shipboard software distribution. It describes the programs used to acquire and record data from IMET systems installed on R/V Knorr and R/V Oceanus. The second part adds appendix material that contains the documentation pages for programs and
subroutines used in the IMET shipboard software system. These items are available through network or diskette access. This report
has been prepared to give this information broader visibility and circulation.Funding was provided by the National Science Foundation under Grant Nos. OCE-92-04034 and OCE-87-09614
KINEMATIC AND KINETIC ANALYSIS OF THE HORIZONTAL HANG CLEAN PERFORMED WITH A VARIETY OF LOADS AND THEIR COMPARISON TO THE SPRINT START
This study evaluated kinetic and kinematic aspects of the horizontal hang clean (H-HC) at a variety of loads and also compares these results to the standing sprint start (SSS). Subjects were tested during the H-HC at 30%, 50% and 70% of their five-repetition maximum (5RM), and during the SSS, using two force platforms. Analysis revealed significant differences for the H-HC conditions for the propulsive phase vertical GRF (p ≤ 0.001), propulsive phase horizontal to vertical GRF ratio (H:V) (p = 0.001), subject/barbell displacement (p ≤ 0.001), and velocity (p ≤ 0.001). The propulsive H:V of the H-HC at 30% of the 5 RM was correlated to the propulsive H:V of the first step of the SSS (p = 0.04, r = 0.55). To maximize subject anterior displacement and velocity and propulsive H:V, practitioners should use the H-HC with loads of 30% of the 5 RM. Training in this manner offers specificity for sprinting starts
High temperature deformation of polycrystalline C40 Mo(Si,Al)2
Polycrystalline Mo(Si,Al)2 with C40 crystal structure was deformed in compression with a strain rate of 10−4 s−1 at 1300 \ub0C. The specimens were deformed to a strain of 10%–15% and showed maximum stresses around 150 MPa prior to pronounced softening. No crack formation or significant increase in porosity could be observed. Post-test microstructure analysis revealed that the material was inhomogeneously deformed on both inter- and intragranular levels. Dynamic recrystallization occurred alongside low angle grain boundary formation in highly deformed grains. Furthermore, complex intragranular deformation fields suggest that slip systems other than 21̄1̄0[0001] may be active during deformation
BIOMECHANICAL ANALYSIS OF LOADED PLYOMETRIC EXERCISES
Plyometric intensity and specificity are determined by the exercises performed. This study assessed ground reaction forces (GRF) in the frontal (F), horizontal-anterior (H), and vertical (V) planes, and the ratio of H to V GRF (H:V) of plyometric exercises and load conditions. Subjects (N=15) performed five plyometric variations with five handheld loads on two force platforms. A two-way RM ANOVA was used. Analysis of F GRF revealed main effects for plyometric exercise (p = 0.004). Analysis of H GRF revealed main effects for plyometric load (p = .042) and plyometric exercise (p ≤ 0.001). Analysis of V GRF revealed main effects for plyometric load (p ≤ 0.001) and plyometric exercise (p ≤ 0.001). Analysis of H:V revealed main effects for plyometric exercise (p ≤ 0.001). Practitioners should use the plyometric exercises and loads that optimize the kinetics and transfer of training
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