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At least 217 records · Page 12Linked to original sources
PubMed1978

Influence of heat, wind, and humidity on ultraviolet radiation injury.

We investigated the influence of heat, wind, and humidity on UVR-induced acute and chronic skin damage of experimental animals housed in environmental chambers and irradiated under controlled conditions. Hairless mice (strain HRS/J) irradiated after an increase of 10 degrees F in skin temperature had more skin damage than irradiated controls. Significantly more Swiss albino mice irradiated for 400 days while maintained at 90 degrees F developed tumors than did those receiving the same amount of UVR but maintained at room temperature. Mice exposed to UVR daily for 4 weeks while kept in wind of 7 mph had greater damage and slower recovery than animals irradiated but protected from wind. Wind also accelerated tumorigenesis in mice than received chronic UVR. Mice kept at 80% relative humidity and given a single dose of UVR had greater skin injury than animals irradiated while at 5% relative humidity. High midity also appears to accelerate skin cancer formation in animals that were exposed to chronic UVR.

Air Movements↗
PubMed2001

Wind-induced ventilation of the giant nests of the leaf-cutting ant Atta vollenweideri.

To understand the significance of elaborate nest architecture for the control of nest climate, we investigated the mechanisms governing nest ventilation in a large field nest of Atta vollenweideri. Surface wind, drawing air from the central tunnels of the nest mound, was observed to be the main driving force for nest ventilation during summer. This mechanism of wind-induced ventilation has so far not been described for social insect colonies. Thermal convection, another possible force driving ventilation, contributed very little. According to their predominant airflow direction, two functionally distinct tunnel groups were identified: outflow tunnels in the upper, central region, and inflow tunnels in the lower, peripheral region of the nest mound. The function of the tunnels was independent of wind direction. Outflow of air through the central tunnels was followed by a delayed inflow through the peripheral tunnels. Leaf-cutting ants design the tunnel openings on the top of the nest with turrets which may reinforce wind-induced nest ventilation.

Animals↗
PubMed1987

Evidence for involvement of N-methylaspartate receptors in 'wind-up' of class 2 neurones in the dorsal horn of the rat.

We have examined the effects of ketamine and kynurenate on the initial response and frequency dependent potentiation of response (wind-up) of class 2 neurones of the rat dorsal horn induced by repeated electrical stimulation of their receptive fields. Iontophoretic kynurenate reduced both the initial response and the wind-up. Iontophoretic or intravenous ketamine had no consistent effect on the initial response but consistently reduced wind-up. N-Methylaspartate receptors therefore appear to contribute to the wind-up, but not the initial response, of class 2 neurones in the rat.

Animals↗
PubMed2005

Using Cesium-137 technique to study the characteristics of different aspect of soil erosion in the Wind-water Erosion Crisscross Region on Loess Plateau of China.

The most serious soil erosion on Loess Plateau exists in the Wind-water Erosion Crisscross Region. In the past 20 years, the types and intensity of soil erosion and its temporal and spatial distribution were studied, but studies on the difference of soil erosion between slope aspects and slope positions in this area have no report. However, it is very important to analyze and evaluate quantitatively the characteristics of different aspects and positions of soil loss for the prevention and treatment of soil erosion in this area. The spatial pattern of net soil loss on 4 downslope transects in four aspects (east, west, south and north) on a typical Mao (round loess mound) in Liudaogou catchment in Wind-water Erosion Crisscross Region was measured in 2000 using the resident cesium-137 deficit technique. The purposes of this investigation were undertaken to determine whether or not 137Cs measurement would give a useful indication of the extent of soil loss and their characteristics from cultivated hillsides in different slope aspect and slope position in the study area. The results showed that the difference of soil erosion in different aspect was significant and the erosion rate was in this order: north > east > south > west. Compared with other areas, the difference of erosion rate between north hillside and south hillside was on the contrary, and the possible explanations could be the effect of wind erosion. Also, the percentage of wind erosion was estimated to be at least larger than 18% of total soil loss by comparing the difference of erosion amount in south hillside and north hillside. The erosion rates on different slope positions in all aspects were also different, the highest net soil loss occurred in the lower slope position, and the upper and middle slope positions were slight. The general trend of net soil loss on sloping surface was to increase in fluctuation with increasing downslope distance.

Cesium Radioisotopes↗
PubMed2004

Compulsory winding in the opposite direction of climbing plants promotes yield.

The stem of kidney bean plant (Phaseolus vulgaris L., cv. Kentucky 101), a typical dextrorse climbing plant, was subjected to compulsorily sinistrorse-winding. The compulsory sinistrorse-winding induced changes in physiological activities. The number of pods with immature seeds (used as vegetable) was doubled and the fresh weight of the pods also significantly increased by sinistrorse-winding. Compulsory sinistrorse-winding increased chlorophyll content, photosynthetic rate, respiration, nodule formation, N(2)-fixation, glutamine synthetase [L-glutamate: ammonia ligase (ADP-forming); E.C. 6.3.1.2] activity and protein content. Thus, it seems to affect the basic physiological processes that promote physiological activities though the action mechanism is unknown.

Biomass↗
PubMed1997

Effect of an NMDA receptor antagonist on the wind-up of neurons in the trigeminal oralis subnucleus.

Extracellular recordings of convergent neurons of the oralis subnucleus of the trigeminal sensory complex were performed in paralysed rats under halothane-N2O-O2 anesthesia using glass micropipettes. The effects of MK801, a noncompetitive NMDA receptor antagonist, were observed on the increased cell activity (wind-up), triggered by the repetition, at a low frequency (0.66 Hz) and high intensity (3 times the threshold of C-fiber response), of electrical stimulation of the receptive field. Successive cumulative doses (up to 1 mg/kg) of MK801 i.v. resulted in a dose-dependent decrease in the responses related to C-fiber input (11 cells). A single dose of 1 mg/kg applied in four cells had effects similar to the 1 mg/kg dose given cumulatively. Three units were either weakly or not modified by MK801. In a second experiment, recordings were performed in 12 cells for 80 min after an injection of a small dose of MK801 (0.15 mg/kg). C input was not significantly modified by the antagonist. The effects of MK801 on the first part of the wind-up response (wind-up proper) peaked between 15 and 50 min and returned to control values at about 80 min. The effects on the postdischarge followed approximately the same time course. It is concluded that despite being devoid of substantia gelatinosa, the oralis subnucleus contains neurons that display an NMDA receptor-linked wind-up similar to the phenomenon described in the dorsal horn of the spinal cord.

Action Potentials↗
PubMedDate not supplied

Glottic configuration in wind instrument players.

INTRODUCTION: Knowledge of occupational voice disorders has gained increased importance as more individuals rely on their voices for their work. Wind instrument players are a specific group of individuals that present intensive use of the vocal tract associated with blowing their instrument. Interestingly, only a small number of reports focus on the laryngeal function of such professionals. AIM: The current study evaluated the laryngeal and vocal tract movement of wind instrument players. MATERIAL AND METHODS: Ten adult wind instrument players were studied with flexible videolaryngoscopy while playing their instrument, in order to observe the movements of the glottis, the vocal tract and the base of the tongue. RESULTS: In all the participants it was observed that musical tones were played with adducted vocal folds and that the greater the technical difficulty reported by the player, the more it was associated with increased lateral tension in the larynx, as well as constriction in the vocal tract. CONCLUSIONS: The larynx controls the airflow that will reach the mouthpiece of the instrument, directly interfering in blowing. Therefore, wind instrument players should also be considered professional voice users.

Adult↗
PubMed2000

Heliospheric X-ray Emission Associated with Charge Transfer of the Solar Wind with Interstellar Neutrals.

X-rays should be generated throughout the heliosphere as a consequence of charge transfer collisions between heavy (Z>2) solar wind ions and interstellar neutrals. The high charge state solar wind ions resulting from these collisions are left in highly excited states and emit extreme ultraviolet or soft X-ray photons. This solar wind charge exchange mechanism applied to cometary neutrals has been used to explain the soft X-ray emission observed from comets. A simple model demonstrates that heliospheric X-ray emission can account for about 25%-50% of the observed soft X-ray background intensities. The spatial and temporal variations of heliospheric X-ray emission should reflect variations in the solar wind flux and composition as well as variations in the distribution of interstellar neutrals within the heliosphere. The heliospheric X-ray "background" can perhaps be identified with the "long-term enhancements" in the soft X-ray background measured by ROSAT.

Journal Article↗
PubMedDate not supplied

Metabolic response to air temperature and wind in day-old mallards and a standard operative temperature scale.

Most duckling mortality occurs during the week following hatching and is often associated with cold, windy, wet weather and scattering of the brood. We estimated the thermoregulatory demands imposed by cold, windy weather on isolated 1-d-old mallard (Anas platyrhynchos) ducklings resting in cover. We measured O2 consumption and evaporative water loss at air temperatures from 5 degrees to 25 degrees C and wind speeds of 0.1, 0.2, 0.5, and 1.0 m/s. Metabolic heat production increased as wind increased or temperature decreased but was less sensitive to wind than that of either adult passerines or small mammals. Evaporative heat loss ranged from 5% to 17% of heat production. Evaporative heat loss and the ratio of evaporative heat loss to metabolic heat production was significantly lower in rest phase. These data were used to define a standard operative temperature (Tes) scale for night or heavy overcast conditions. An increase of wind speed from 0.1 to 1 m/s decreased Tes by 3 degrees -5 degrees C.

Animals↗
PubMed1989

Dentofacial morphology in children playing musical wind instruments: a longitudinal study.

Playing wind instruments requires increased ventilation and increased orofacial muscle activity. The aim of the present investigation was to study the longitudinal effects on the dentofacial morphology of increased ventilation and orofacial muscle activity associated with playing wind instruments. Lateral cephalograms and dental casts obtained from wind instrument players at the ages of 6, 9, 12, and 15 years were studied and compared to control groups. In addition information was obtained as to how many hours per day they practised their instruments. Significant differences between the musicians and controls were found. The musicians had a decreased anterior facial height and wider dental arches. The findings are interpreted as being due to increased orofacial muscle activity and increased intra-oral pressure resulting from wind instrument playing.

Cephalometry↗
PubMed2000

The effects of ketamine on the temporal summation (wind-up) of the R(III) nociceptive flexion reflex and pain in humans.

UNLABELLED: Animal studies have suggested that the temporal summation of nociceptive inputs might play a significant role in the development of central sensitization (i.e., hyperexcitability of central nociceptive neurons) and hyperalgesia via the activation of N-methyl-D-aspartate receptors. To further analyze these processes in humans, we evaluated the effects of small systemic doses of ketamine on the temporal summation (i.e., wind-up) of both the nociceptive flexion (R(III)) reflex and sensations of pain in six healthy volunteers. The R(III) reflex was recorded from the biceps femoris and was elicited by electrical stimulation of the sural nerve. First, the recruitment (stimulus/response) curve for the reflex was built using stimuli up to the pain tolerance threshold (applied once every 6 s). A series of 15 stimuli was then applied once a second at an intensity of 1.2 times the reflex threshold. These procedures were performed both before and after the randomized IV injection of either 0.15 mg/kg ketamine or a placebo. The R(III) reflex threshold and its recruitment curve were not significantly altered after the injection of ketamine or placebo. By contrast, the significant increases (i.e., wind-up) in both the reflex responses and the sensations of pain observed during the higher frequency stimulation were significantly reduced after the administration of ketamine, but not placebo. This method might be useful for quantifying and analyzing the wind-up phenomenon and, thus, for studying the neurophysiological and pharmacological mechanisms underlying hyperalgesia in humans. IMPLICATIONS: The wind-up phenomenon (i.e., the progressive increase of the responses induced by repetitive nociceptive stimuli) was characterized in humans by using electrophysiological recordings of the nociceptive flexion reflex. We showed that, as in animals, this phenomenon, which might represent an elementary form of the central sensitization involved in various painful syndromes, depends on the activation of N-methyl-D-aspartate receptors, because it was selectively reduced after the administration of ketamine.

Adult↗
PubMed1998

Management of impending penile prosthesis erosion with a polytetrafluoroethylene distal wind sock graft.

PURPOSE: Erosion of penile prostheses can be calamitous, often leaving patients unable to accommodate further implants. There is a paucity of literature describing impending erosion of penile prosthesis. We report on 5 patients with impending erosion of a penile prosthesis who underwent polytetrafluoroethylene distal wind sock graft placement. MATERIALS AND METHODS: From 1993 to 1997, 5 patients with a mean age of 49 years and impending penile prosthesis erosion underwent 6 revisions using a polytetrafluoroethylene distal wind sock graft. Two patients underwent simultaneous bilateral grafts while 1 patient underwent separate right and left grafts 3 years apart. Indications for reconstruction included distal migration of the prosthetic cylinders into the glans in 4 patients and impingement of the distal urethra in 2. Of the patients 3 were spinal cord injured, 1 had lumbar radiculopathy and 1 had a history of pelvic irradiation. Inflatable prostheses were implanted in 4 patients, while 1 received a malleable prosthesis. RESULTS: Patients underwent a mean of 1.5 penile prosthetic revisions (0 to 4) before diagnosis of impending erosion. An interval of 8 to 144 months (mean 66) elapsed from the most recent penile prosthesis insertion until distal wind sock graft placement. Mean operative time was 1 hour 51 minutes (1.3 to 2.5 hours). Mean hospital stay was 6.3 days (3 to 12). At a mean followup of 32 months (0.7 to 5.2 years) all patients had satisfactory and functional erections with no pain or evidence of impending erosion or penile prosthesis infection. CONCLUSIONS: Erosion of a penile prosthesis can have disastrous consequences. We describe a safe and effective technique for managing impending penile prosthesis erosion using a polytetrafluoroethylene distal wind sock graft.

Humans↗
PubMed2006

Drivers of the solar wind: then and now.

Early spacecraft data in the 1960s revealed solar wind properties, which could not be well explained by models in which the electron pressure gradient was the principal accelerating force. The Alfvén waves discovered around 1970 were thought for a while to provide additional energy and momentum, but they ultimately failed to explain the rapid acceleration of the fast wind close to the Sun. By the late 1970s, various data were suggesting the importance of the ion-cyclotron resonance far from the Sun. This notion was soon applied to the acceleration region close to the Sun. The models, which resulted, suggested that the fast wind could be driven mainly by the proton pressure gradient. Since the mid-1990s, Solar and Heliospheric Observatory has provided remarkable data, which have verified some of the predictions of these theories, and given impetus to studies of the ion-cyclotron resonance as the principal mechanism for heating the coronal holes, and ultimately driving the fast wind. After a historical review, we discuss the basic ideas behind current research, emphasizing the particle kinetics. We discuss remaining problems, especially the source of the ion-cyclotron resonant waves.

Journal Article↗
PubMed2000

Estimation of the entropy of the solar wind flow

We analyze a time series of velocities of the low-speed stream measured by the Helios spacecraft in the inner heliosphere, which is the region of space dominated by the solar wind flow. We use a nonlinear filter to give a faithful representation of the solar wind nonlinear behavior. We have demonstrated that the influence of noise in the data can be much more efficiently reduced by a nonlinear filter than with the conventional (linear) filters, and this allows a more realistic calculation of the solar wind entropy. The resulting Kolmogorov entropy is positive, and possibly the largest Lyapunov exponent is also positive locally, which would exhibit exponential sensitivity to initial conditions. Thus, these results show that the solar wind in the inner heliosphere is most likely a deterministic chaotic system.

Journal Article↗
PubMed2002

Experimental measurement of wind-sand flux and sand transport for naturally mixed sands.

This article presents an experimental test and a program to empirically fit experimental data for the horizontal flux of wind-blown sand passing through a unit area along a vertical direction per unit time. The experimental data for the sand flow flux as a function of the height for naturally mixed sands, which were chosen from a sand dune at the southeastern edge of the Tengger desert, were measured with a sand collector in a field wind tunnel. On the basis of the experimental data and a least squares method, a fitting program is proposed here and, further, an explicit form of an empirical formula varying with height and axial wind velocity or friction velocity for the flux structure of the sands is gained. After that, we obtain an explicit form of the empirical equation for the measurement of streamwise sand transport per unit width and unit time by integrating the empirical formula for sand flux along the height direction and considering the contribution of sand creep. Finally, we evaluate the effectiveness of the predictions of some equations, especially the well-known Bagnold equation and Kawamura equation, for predicting streamwise wind-sand transport using the empirical equation obtained for mixed sands. The results show that the predictions from Bagnold's equation in the region of friction velocity u(*)>0.47 m/s and Kawamura's equation in the region u(*t)<or=u(*)<0.35 m/s are effective. Meanwhile, the measurement results given from the empirical equation smoothly transit from Kawamura's prediction to Bagnold's prediction as the friction velocity increases in the range 0.35 m/s<u(*)<0.47 m/s.

Journal Article↗
PubMed2003

Winding angle variance of Fortuin-Kasteleyn contours.

The variance in the winding number of various random fractal curves, including the self-avoiding walk, the loop-erased random walk, contours of Fortuin-Kastelyn clusters, and stochastic Loewner evolution, has been studied by numerous researchers. Usually the focus has been on the winding at the end points. We measure the variance in winding number at typical points along the curve. More generally, we study the winding at points where k strands come together, and some adjacent strands may be conditioned not to hit each other. The measured values are consistent with an interesting conjecture.

Journal Article↗
PubMed2005

Prediction of underwater sound levels from rain and wind.

Wind and rain generated ambient sound from the ocean surface represents the background baseline of ocean noise. Understanding these ambient sounds under different conditions will facilitate other scientific studies. For example, measurement of the processes producing the sound, assessment of sonar performance, and helping to understand the influence of anthropogenic generated noise on marine mammals. About 90 buoy-months of ocean ambient sound data have been collected using Acoustic Rain Gauges in different open-ocean locations in the Tropical Pacific Ocean. Distinct ambient sound spectra for various rainfall rates and wind speeds are identified through a series of discrimination processes. Five divisions of the sound spectra associated with different sound generating mechanisms can be predicted using wind speed and rainfall rate as input variables. The ambient sound data collected from the Intertropical Convergence Zone are used to construct the prediction algorithms, and are tested on the data from the Western Pacific Warm Pool. This physically based semi-empirical model predicts the ambient sound spectra (0.5-50 kHz) at rainfall rates from 2-200 mm/h and wind speeds from 2 to 14 m/s.

Journal Article↗
PubMed2004

Solar wind-induced atmospheric erosion at Mars: first results from ASPERA-3 on Mars Express.

The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the martian topside atmosphere to solar wind plasma forcing. The low-altitude penetration of solar wind plasma and the energization of ionospheric plasma may be due to solar wind irregularities or perturbations, to magnetic anomalies at Mars, or both.

Journal Article↗