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At least 199 records · Page 11Linked to original sources
PubMed1988

Reduction of sensory activity produced by cercal displacement modifies response of wind-sensitive interneurons in the cockroach.

The cockroach can reduce the amount of sensory activity received by its CNS from the cerci, paired wind-responsive appendages. This reduction is produced by medial displacement of the cerci, a movement the animal performs naturally during flying. We demonstrate here that this sensory reduction significantly reduces activity of the postsynaptic wind-sensitive interneurons in the abdominal nerve cord, cells which carry the wind information to higher centers of the nervous system. In addition, we have found that the wind-evoked activity of two identified giant interneurons that are involved in escape and locomotion behaviors, is significantly reduced by cercal displacement.

Action Potentials↗
PubMed1985

A mathematical analysis of the influence of adverse and favourable winds on sprinting.

A mathematical analysis of running performance, based on the first law of thermodynamics and originally derived for still air conditions, is extended to account for the effects of favourable and adverse winds. Solutions to the full theory have been obtained by numerical integration of the governing equations. Simplifications to the full calculation procedure have also been investigated. Calculations for races over a distance of 100 m show that the advantage to an athlete of a following wind increases progressively with increasing wind speed. A favourable wind of 2 ms-1 provides a benefit of about 0.18 s on running time.

Air Movements↗
PubMed2006

Wind-induced dust generation and transport mechanics on a bare agricultural field.

Strong atmospheric winds may cause wind erosion and dust emissions on bare, dry, erodible fields. Since these dust emissions may exceed particulate matter limits established by the United States Environmental Protection Agency, information on dust generation and transport mechanics is needed to determine the particulate hazard of dust sources. Measurements of climatic variables and airborne sediment mass and concentration were made during three strong wind events on a bare, fine sandy loam field in west Texas. This study clearly shows that dust flux estimates were very sensitive to dust concentration measurement height. PM10 flux values estimated between heights of 2 and 5m were 2-5 times those estimated between heights of 5 and 10 m. Tower placement in relation to the upwind unerodible boundary produced significant differences in dust flux that varied with storm intensity. During the most intense storm event, the PM10 flux between heights of 2 and 5m measured at the tower 200 m from the unerodible boundary was almost 2.5 times as that measured at the tower 100 m from the unerodible boundary. Vertical PM10 dust flux was closely related with horizontal sediment flux only when the winds came from the same direction during the entire duration of horizontal sediment flux measurements.

Agriculture↗
PubMed2001

Guidelines for the inclusion of low wind speed conditions into risk assessments.

Although they are not often considered in risk assessments or safety cases, low wind speed conditions are likely to produce many of the worst case dispersion scenarios, especially for situations where dense vapour clouds would form close to the ground. The results of previous review and validation studies, undertaken by the authors for the UK Health and Safety Executive, have been drawn together in this paper to provide guidelines for the practical application of appropriate modelling of scenarios involving low wind speeds within quantified risk assessments. The production of these guidelines has been achieved by using example risk assessments covering the storage of chlorine, bromine, LPG and Liquid Oxygen, for each of which sensitivity studies were also undertaken. These demonstrated that the inclusion of low wind speeds has varying effects, depending on the material considered, which could be as much as 1-2 orders of magnitude. Most importantly, it also showed that, when low wind speeds are included, it is not only their dispersion effects but also their effects on source term and impact on the population, which need to be considered to ensure that the calculated risks are neither overly conservative nor optimistic.

Air Pollutants↗
PubMed2000

Evaluation of watering to control dust in high winds.

A field study was conducted to determine the effectiveness of watering in controlling PM10 emissions under high wind conditions. The focus of the study was the pickup of soil by a belly scraper at a landfill. Four low-volume PM10 samplers were positioned downwind of the storage pile (at two distances, 80 and 110 m, and two elevations, 1 and 3 m) and one was located upwind at 3 m elevation. Integrating nephelometers, which measure the particulate light scattering coefficient, bsp, were also set up at locations 80 and 110 m downwind of the storage pile. Wind speed and direction were measured on-site. Samples were collected for two periods, one with and one without water being applied. Watering was effective at reducing PM10 emissions at wind speeds up to the maximum 18 m sec-1 observed at the landfill soil pickup operation. Measurement of bsp provided an indication of PM10 concentrations with better time resolution than samplers, but not with sufficient resolution, under the instrumental conditions used, to correlate with wind gusts.

Air Pollution↗
PubMed2004

Perception and annoyance due to wind turbine noise--a dose-response relationship.

Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines' impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose-response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose-response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose-response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents' attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.

Adolescent↗
PubMed1997

Independent coding of wind direction in cockroach giant interneurons.

Independent coding of wind direction in cockroach giant interneurons. J. Neurophysiol. 78: 2655-2661, 1997. In this study we examined the possible role of cell-to-cell interactions in the localization processing of a wind stimulus by the cockroach cercal system. Such sensory processing is performed primarily by pairs of giant interneurons (GIs), a group of highly directional cells. We have studied possible interactions among these GIs by comparing the wind sensitivity of a given GI before and after removing another GI with the use of photoablation. Testing various combinations of GI pairs did not reveal any suprathreshold interactions. This was true for all unilateral GI pairs on the left or right side as well as all the bilateral GI pairs (left and right homologues). Those experiments in which we were able to measure synaptic activity did not reveal subthreshold interactions between the GIs either. We conclude that the GIs code independently for a given wind direction without local GI-GI interactions. We discuss the possible implications of the absence of local interactions on information transfer in the first station of the escape circuit.

Abdomen↗
PubMed2007

Analyzing the effect of wind on flight: pitfalls and solutions.

How flying organisms alter their air speed in response to wind is important in theories of flight energetics. Numerous studies have investigated the relationship between air and wind as a function of ground speed and air speed. This study shows that this approach can lead to erroneous results, due to spurious correlations. An alternative way to analyze air speed is proposed that overcomes the problems of one-dimensional linear models. The new model is non-linear and has two explanatory variables. Using two synthetic data sets with known properties and a data set with real observations of migratory bird tracks and wind observations, we illustrate the weaknesses of the conventional analysis as well as the strengths of the newly proposed model. This leads to the conclusion that for many studies a reanalysis of the effect of wind on air speed is desirable.

Animals↗
PubMed2003

[Parity and wind impact on the frequency of Anopheles marajoara, São Paulo, Brazil].

OBJECTIVE: To evaluate the impact of wind velocity on the behavior of An. marajoara population and its parity. METHODS: Collections were made bimonthly from January 1999 to February 2000 in the municipality of Ilha Comprida, Brazil. Adult mosquitoes were captured with a battery hand aspirator. Mann-Whitney test was applied to verify the wind impact on mosquito behavior. Polovodova technique and Christophers and Mer's follicular development analysis were used to determine parity. RESULTS: A total of 11,833 mosquitoes were captured, including 3,072 An. marajoara specimens. The peak of activity of An. marajoara occurred from 2 to 5 AM. Amongst 1,006 An. marajoara females who had their ovarioles dissected, it was found 530 (52.7%) nulliparous, 432 (42.9%) uniparous, 24 (2.4%) biparous and 1 multiparous. According to Christophers and Mer analysis, 982 (97.6%) had their follicles in phases I and II, 7 in phases III and IV, and 17 in phase V. The frequency of An. marajoara was significantly lower when wind velocity was 3 km/h or more or below 3 km/h. CONCLUSIONS: An. marajoara mosquitoes were more active at night. About 50% of dissected An. marajoara females were oniparous. Another important finding was the high proportion of females (97.6%) with follicles in the Christophers and Mer's phases I and II, suggesting the presence of gonotrophic concordance. Wind velocity equal or higher than 3 km/h considerably reduced the frequency of An. marajoara.

Aedes↗
PubMed2005

Fire and grazing effects on wind erosion, soil water content, and soil temperature.

Selective grazing of burned patches can be intense if animal distribution is not controlled and may compound the independent effects of fire and grazing on soil characteristics. Our objectives were to quantify the effects of patch burning and grazing on wind erosion, soil water content, and soil temperature in sand sagebrush (Artemisia filifolia Torr.) mixed prairie. We selected 24, 4-ha plots near Woodward, OK. Four plots were burned during autumn (mid-November) and four during spring (mid-April), and four served as nonburned controls for each of two years. Cattle were given unrestricted access (April-September) to burned patches (<2% of pastures) and utilization was about 78%. Wind erosion, soil water content, and soil temperature were measured monthly. Wind erosion varied by burn, year, and sampling height. Wind erosion was about 2 to 48 times greater on autumn-burned plots than nonburned plots during the dormant period (December-April). Growing-season (April-August) erosion was greatest during spring. Erosion of spring-burned sites was double that of nonburned sites both years. Growing-season erosion from autumn-burned sites was similar to nonburned sites except for one year with a dry April-May. Soil water content was unaffected by patch burn treatments. Soils of burned plots were 1 to 3 degrees C warmer than those of nonburned plots, based on mid-day measurements. Lower water holding and deep percolation capacity of sandy soils probably moderated effects on soil water content and soil temperature. Despite poor growing conditions following fire and heavy selective grazing of burned patches, no blowouts or drifts were observed.

Animals↗
PubMed2007

[A rabbit model of cervical spondylosis established by stimulation of wind, cold and dampness].

OBJECTIVE: To make an animal model of cervical spondylosis (arthralgia syndrome type) with stimulation of wind, cold, and dampness. METHODS: Twenty-four 8 months old male New Zealand white rabbits were randomly allocated into four groups: normal control group, light stimulation group, moderate stimulation group and severe stimulation group. The wind speed was 10.8-13.8 m/s, the temperature was (5+/-0.5)degrees centigrade, and the humidity was 100%. The rabbits of light, moderate, and severe stimulation groups were kept in the above-mentioned environments for 4 hours everyday, and for a total of 32, 64, and 128 hours, respectively. The intervertebral discs were stained with HE method, and observed with a light microscope. Prostaglandin E(2) (PGE(2)), 6-ketone-prostaglandin F1alpha (6-K-PGF(1alpha)) and thromboxane B(2) (TXB(2)) contents were measured by ELISA. Fas and Bcl-2 expressions were examined by immunohistochemical avidin-biotin peroxidose complex technique. Interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), and transforming growth factor beta (TGF-beta) mRNA expressions were examined by reverse transcription-polymerase chain reaction. RESULTS: The nucleus pulposus of rabbits in the light and moderate stimulation groups shrunken, and in the severe stimulation group, the anulus fibrosus loosed or ruptured, and the cartilage end-plate became proliferated. Compared with rabbits in the normal control group, the PGE(2) content rose in the light stimulation group, the contents of PGE(2), 6-K-PGF(1alpha), and TXB(2) increased, the expressions of IL-1beta and TNF-alpha mRNAs and Fas were up-regulated, and the expressions of TGF-beta mRNA and Bcl-2 were down-regulated in the moderate and severe stimulation groups. The expression of Fas was up-regulated mostly and Bcl-2 was down-regulated mostly in the severe group. CONCLUSION: Moderate and severe stimulations of wind, cold and dampness can lead to degeneration of cervical intervertebral discs of rabbits. The model corresponds to the theory of traditional Chinese medicine about arthralgia syndrome caused by wind, cold and dampness.

Animals↗
PubMed2000

A wind tunnel bioassay system for screening mosquito repellents.

A wind tunnel bioassay system to screen mosquito repellents is described. A wind tunnel is utilized to exploit the upwind flight response of host-seeking mosquitoes. Mosquitoes within the wind tunnel are activated with human breath, fly upwind, and land on heated chick skins. This behavioral sequence results in a consistently high percentage of the test population approaching repellent or control stimuli. The bioassay system is calibrated with diethyl methylbenzamide against Aedes aegypti and demonstrates a reproducible dose-response relationship. The persistence of diethyl methyl benzamide after a 1-h period is also recorded. The design of the bioassay system permits simultaneous, independent testing of 3 candidate repellents. The wind tunnel bioassay system is compared to other techniques for evaluating mosquito repellents.

Aedes↗
PubMed2005

[Dust storms trend in the Capital Circle of China over the past 50 years and its correlation with temperature, precipitation and wind].

The trends of number of dust storm days of the selected 11 meteorological stations from their established year to 2000 as well as their correlations with temperature, precipitation and wind are revealed. The number of dust storm days of the Capital Circle of China is distinctly variable in space and time. The numbers of dust storm days of the western area are far more than those of the eastern area. The interannual variability of number of dust storm days is remarkable. The number of dust storm days of the following 7 stations, Erlianhaote, Abaga, Xilinhaote, Fengning, Zhangjiakou, Huailai and Beijing, declined along the past decades, but those of the other four stations had no significant upward or downward trends. There is a marked seasonality of the number of dust storm days, and the maximum was in April. The correlation between number of dust storm days and number of days of mean wind velocity > 5 m/s, which is critical wind velocity to entrain sand into the air, was strongest among the three climatic factor. There were significant positive correlations between the number of dust storm days and number of days of mean wind velocity > 5 m/s in 6 stations. The second strongest climatic factor correlated with the number of dust storm days is temperature. There are significant negative correlations between the number of dust storm days and mean annual temperature, mean winter temperature, mean spring temperature in 3 or 4 stations. The correlation between the number of dust storm days and precipitation is weakest. Only one station, Zhurihe, showes significant negative correlation between the number of dust storm days and spring rainfall. There are 4 stations whose number of dust storm days don't significantly correlate with the climate. In the end, the spatial-temporal variability of dust storms and its relation with climate in the Capital Circle of China were discussed thoroughly.

Air Pollutants↗
PubMed2005

[Attenuation of photosynthetically available radiation (PAR) in Meiliang Bay under different winds and waves].

Based on the successive underwater irradiance measurement in situ from Jul. 12 to 17 in 2003, the attenuation of photosynthetically available radiation (PAR) and euphotic depth in Meiliang Bay were analyzed under different winds and waves. The results showed that the downward PAR attenuation coefficients ranged from 2.63 to 4.7 m(-1), with an average of 3.63 +/- 0.47 x m(-1), and the corresponding euphotic depth ranged from 0.98 to 1.75 m, with an average of 1.29 +/- 0.18 m, which demonstrated that phytoplankton and macrophyte could not grow below 1.5 m due to the lack of adequate solar radiation. The total suspended solids resulted from wind and wave increased the attenuation of light, with the downward attenuation coefficients of PAR being 2.63, 3.72 and 4.37 x m(-1) under small, medium and large wind and wave, respectively. Significant linear correlations were found between transparence, PAR attenuation coefficient, euphotic depth and total suspended solid, especially inorganic suspended solid, while chlorophyll a was the most nonsignificant light attenuator. Multiple stepwise linear regressions showed that inorganic suspended solid was the most important light attenuator dominating the light attenuation in wind-exposed Meiliang Bay.

Fresh Water↗
PubMed1991

Possible introduction of epizootic hemorrhagic disease of deer virus (serotype 2) and bluetongue virus (serotype 11) into British Columbia in 1987 and 1988 by infected Culicoides carried on the wind.

Outbreaks of epizootic hemorrhagic disease of deer and of bluetongue began in British Columbia in August and October 1987 respectively and recrudescence of infection by both viruses was detected the following year in August. Weather records for up to 18 days before the initial outbreaks of disease, isolation of virus or seroconversion were examined to determine if the viruses could have been introduced by infected Culicoides carried on the wind. Data on temperature, rainfall, wind speed and direction and pressure together with backward trajectory analysis showed that there were suitable winds which could have introduced Culicoides infected with epizootic hemorrhagic disease of deer virus on 13 August 1987 (14 days before disease was observed), Culicoides infected with bluetongue virus on 1 October 1987 (7 days before virus was isolated and 13 days before disease in sheep) and Culicoides infected with bluetongue or epizootic hemorrhagic disease of deer viruses on 20 July 1988 (15 days before seroconversion was detected). The arrival on 13 August 1987 coincided with the passage of a cold front and rain and that on 1 October 1987 with a fall in temperature and calm winds. The source of the Culicoides before arrival could have been the Okanogan Valley as far south as the junction of the Okanogan and Columbia rivers in Washington, USA. Flight would have been at temperatures of 12.6 degrees C or higher and at heights up to 1.5 km.

Animals↗
PubMed1990

A simultaneous interpretation by wind speed and direction, of ambient air CO in Athens, Greece.

The rectangular frequency isopleth diagram, a data presentation technique, has been applied to examine the effect of wind speed and direction, acting simultaneously, on the CO concentrations. The CO concentrations decrease, in the majority of directions and wind speed intervals, as the wind speed increases. The absolute maximum of CO concentrations occur when the wind blows from highly urbanized and industrialized area. The influence of the CO on human health is also discussed.

Air Movements↗
PubMed1986

Wind chill reconsidered, Siple revisited.

Experiments similar to those establishing the concepts of wind chill have been done with bare and "clothed" cylinders and when the clothing was wet at temperatures above and below freezing. Clothing prevented the heat loss that was associated with increased wind velocity in the bare cylinder. With wet clothing, evaporation increased with wind velocity but heat loss did not, and raincoats or freezing markedly reduced wet heat loss. The concept of wind chill applies only to unprotected objects.

Air Movements↗
PubMed1995

Assessment of aerobic and anaerobic demands of dinghy sailing at different wind velocities.

The aim of this study was to assess the oxygen uptake (VO2), heart rate (HR) and blood lactate concentration ([Lab]) during actual dinghy sailing at different wind velocities. Eight top class Laser sailors volunteered to participate in the study. In the laboratory, each subject performed an incremental exercise test on a cycle ergometer to the point of exhaustion. Maximum oxygen uptake (VO2max) and maximum heart rate (HR max) were assessed by means of a Cosmed K2 (K2) portable oxygen analyser while the accuracy of the K2 was simultaneously examined by comparing it with the Douglas bag method. On water each subject underwent a 10 minute continuous upwind sailing test. The average percentages of VO2max and HR max during sailing and the post-test [La(b)] were 39 +/- 6%, 74 +/- 11% and 2.3 +/- 0.8 mM, respectively. Values of the three measured variables for each subject were significantly correlated to wind velocity (r = 0.73, 0.87 and 0.88, respectively). The results of the study suggest that the metabolic and cardiorespiratory demands of dinghy sailing predominantly depend on the wind conditions. Aerobic capacity is only moderately taxed in dinghy sailing and should not be emphasized in training, whereas anaerobic metabolism plays an increasing role in stronger winds.

Adult↗