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At least 109 records · Page 6Linked to original sources
PubMed1997

Climatic controls of the cool human thermal sensation in a summertime onshore wind.

Afternoon observations in summer comparing shoreline with inland atmospheric conditions were made during onshore winds at Victoria, British Columbia, Canada. The onshore wind came from a cool water surface. Mean monthly water temperatures near to shore were between 11 and 11.5 degrees C. The onshore wind brought lower air, ground surface radiant and sky radiant temperatures; lower humidity and greater wind speed. All of these combine to produce a cooler human environment at the shoreline than inland. The relative importance of climatic elements in producing the cooler environment was assessed using sensitivity analyses with eight different human thermal exchange models/indices. Air temperature and wind speed had the greatest effect, followed by ground surface radiant temperature, sky radiant temperature and humidity. Wind speed is the most practical element to consider when trying to maximize human comfort along the shoreline.

British Columbia↗
PubMed1996

The responses of skin blood flow, mean arterial pressure and R-R interval induced by cold stimulation with cold wind and ice water.

This study was designed to evaluate the peripheral circulation response to cold wind stimulation. Skin blood flow (SBF), ECG R-R intervals (RRs) and mean arterial pressure (MAP) were measured in ten healthy men under strictly controlled conditions. Cold wind flow and ice water bath were prepared as cold stimulations. The subjects were exposed to each cold stimulation and the values of the responses were simultaneously recorded. The cold wind stimulation reduced SBF (maximally 40.4 +/- 3.2%) and increased MAP (maximally 106.9 +/- 1.3%), but did not affect RRs. On the other hand, all parameters were affected by the ice water stimulation, which reduced SBF to 16.4 +/- 1.2% and RRs to 85.1 +/- 3.0%, and increased MAP to 130.6 +/- 2.4% compared with the control state. All subjects suffered from intense pain during the ice water but not the cold wind stimulation, and two of them were eliminated from this study because of vagotonia. After phentolamine iontophoresis was used to block the receptor of peripheral alpha-adrenergic nerve terminals, the cold wind stimulation did not affect SBF. These results suggest that cold wind stimulation is a useful test for evaluating peripheral alpha-adrenergic nerve function in relation to cold sensation, without increase of RRs and noxious pain.

Adolescent↗
PubMed1999

The effect of wind direction on the observed size distribution of particle adsorbed polycyclic aromatic hydrocarbons on an inner city sampling site.

An investigation of the variability in the size distribution of particle adsorbed polycyclic aromatic hydrocarbons (PAHs) on an inner city sampling site showed differences depending on the wind direction. Particle size distributions of PAHs from outdoor air sampling were measured in Munich from 1994 to 1997. The sampling site is located northeast of a crossing with heavy traffic and southwest of a large inner city park. Depending on the wind direction, three different size distributions of particle adsorbed PAHs were observed. The maximum PAH concentration on very small particles (geometric mean diameter 75 nm) was observed with wind from west to southwest coming directly from the crossing area or the roads with heavy traffic. The maximum PAH concentration on particles with geometric mean diameter of 260 nm was found on days with wind from the built-up area north of the sampling site. On particles with geometric mean diameter of 920 nm the maximum PAH concentration was found on days with main wind directions from northeast to east. On these days the wind is blowing from the direction of the city park nearby. The distribution of particle adsorbed PAHs within different particle size classes is substantially influenced by the distance of the sampling site from strong sources of PAH loaded particulate matter.

Cities↗
PubMed1999

The effect of wind speed and direction on the distribution of sewage-associated bacteria.

A study of the relationship between wind and the distribution of sewage-associated bacteria was undertaken at a location where the sewage was discharged into the sea adjacent to the mouth of a river. The numbers of presumptive Escherichia coli were determined in 149 sea-water samples taken from three locations at distances of 1.9, 2.4 and 4.3 km from the outfall. On each sampling occasion, data on the wind speed and direction in the 3 h prior to collection of the samples were also collected. Analysis of these data demonstrated a significant role for wind speed and direction. With respect to wind direction, the numbers of presumptive E. coli present in a sample were significantly higher when the sample site lay downwind of the outfall. Wind speed was shown to have an influence on the numbers of presumptive E. coli only when the sample site was downwind of the outfall. In an analysis of 61 samples, an inverse correlation (r2 = 0.73) between salinity and log presumptive E. coli numbers was demonstrated. These data demonstrate that wind speed and direction at the time of sampling significantly influence the numbers of presumptive E. coli detected in any sea-water sample. It is argued that failure to pay sufficient attention to these parameters in the design of monitoring programmes may result in the generation of data that could provide a seriously distorted picture of the microbiological status of a water body.

Colony Count, Microbial↗
PubMed2005

Foliage shedding in deciduous forests lifts up long-distance seed dispersal by wind.

Seed terminal velocity and release height are recognized as key biotic determinants of long-distance dispersal (LDD) of seeds by wind. Yet, potential determinants at the ecosystem level, such as seasonal dynamics in foliage density characterizing many deciduous forests, have received much less attention. We integrated detailed field observations and experiments with a mechanistic wind dispersal model to assess how seasonal variation in foliage density, estimated by leaf-area index (LAI), affects LDD in deciduous forests. We found that the model, previously shown to accurately predict seed dispersal by wind, also reliably describes the effects of LAI variation on wind statistics for a wide range of canopy types. Sparser canopies are characterized by more organized vertical eddy motion that promotes LDD by uplifting seeds to higher elevations where winds are stronger. Yet, sparser canopies are also characterized by reduced mean windspeed aloft. We showed that former effect more than compensates for the latter, i.e., conditions of low LAI are favorable for LDD. This may account for the tendency of many temperate tree species to restrict seed release to either early spring or late fall, when LAI is relatively low. Sensitivity analysis reveals that the typical seasonal variation in LAI can be more important to LDD of seeds by wind than the natural variation in seed terminal velocity. Because our model accurately describes the effects of LAI variation for distinctly different sites, species, and life forms, we suggest that its results reflect a general association between LDD and foliage density dynamics.

Biological Evolution↗
PubMed1992

Wind-induced plant motion immediately increases cytosolic calcium.

Wind is one of the most unusual and more dramatic of the environmental signals to modify plant development. Wind-stimulated crops are also known to experience considerable reductions in growth and subsequent yield. There is at present no experimental data to suggest how wind signals are perceived and transduced by plant cells. We have genetically transformed Nicotiana plumbaginifolia to express aequorin and thus produced luminous plants that directly report cytosolic calcium by emitting blue light. With these plants we have found wind stimulation to cause immediate increases in cytosolic calcium and our evidence, based on the use of specific inhibitors, suggests that this calcium is mobilized from organelle sources. Our data further suggest that wind-induced movement of tissues, by mechanically stimulating and stressing constituent plant cells, is responsible for the immediate elevation of cytosolic calcium; increases occur only when the plant tissue is actually in motion. Repeated wind stimulation renders the cells refractory to further calcium signaling but responsiveness is rapidly recovered when stimulation is subsequently diminished. Our data suggest that mechanoperception in plant cells may possibly be transduced through intracellular calcium. Since mechanoperception and transduction are considered crucial to plant morphogenesis, our observations suggest that calcium could be central in the control and generation of plant form.

Aequorin↗
PubMed2005

Particle inhalability at low wind speeds.

Accurate quantification of the dose delivered by aerosol exposures is essential for estimating the risk of potential adverse health effects. The fraction of airborne particles that can enter the nose or mouth during inhalation is referred to as the inspirable particulate mass fraction. This inhalable fraction is equivalent to delivered dose for particles greater than approximately 25 microm (aerodynamic particle diameter, d(ae)), which deposit completely and almost exclusively in the extrathoracic airways. Particle inhalability at high wind speeds (1-9 m/s) has been well characterized. However, there is a paucity of data describing the inhalability of particles at low wind speeds (< or =0.3 m/s), which are typical of indoor environments. High-wind-speed criteria poorly describe inhalability at low wind speeds. Based on the aspiration efficiencies of blunt and sharp-edged inlets, a function was developed for oral inhalability, P(I(O)), of particles at low wind speeds. This function predicts a slow decline in P(I(O)) from 0.95 at d(ae)= 8 microm, to 0.5 at d(ae) = 74 microm, and 0.1 at d(ae)= 175 microm. Data available from the literature for inhalability at relatively low wind speeds during oral breathing are well described by this logistic function (r(2)= 0.69).

Aerosols↗
PubMed2005

Phototropic response induced by wind loading in Maritime pine seedlings (Pinus pinaster Aït.).

Both woody and herbaceous plant species are known to respond to wind loading, with consequences for growth and morphology. Wind has usually been classified as a mechanical stress which is detrimental to plant growth. Few experiments exist whereby plants and, in particular, woody species are exposed to wind, as opposed to mechanical perturbation by touching, flexing or shaking. Such experiments have always been short term and often carried out in wind tunnels in a controlled greenhouse environment. This study introduces an experiment to test the responses of Maritime pine (Pinus pinaster Aït.) seedlings to recurrent and short wind loading in the field, over two growing seasons. These experiments provide evidence that periodic short-term exposure to wind can induce phototropic responses in the early stage of pine seedlings' development. An interpretation is proposed in terms of efficiency to light tracking and hypotheses are discussed concerning the underlying physiological process.

Phototropism↗
PubMed1977

Influence of wind on chronic ultraviolet light-induced carcinogenesis.

Wind enhances the carcinogenic effect of chronic Iltraviolet radiation (UVL). This was demonstrated in hairless mice that were irradiated for 42 weeks with mercury are lamps. One group of animals was exposed to continuous wind flow of 2.7 m/s except for the daily I-2 min time interval when they were removed from the wind tunnel and irradiated. Another group of animals received identical irradiation but were protected from wind. The first tumour appeared in the UVL and wind group after 105 days of irradiation, and at 164 days of irradiation all surviving mice in the group had developed tumours. The group of mice receiving identical irradiation but protected from wind had their first tumour appear at 154 days of irradiation, and by 164 days of irradiation only 40% of the mice had developed tumours.

Air Movements↗
PubMed2004

Wind as a long-distance dispersal vehicle in the Southern Hemisphere.

Anisotropic (direction-dependent) long-distance dispersal (LDD) by wind has been invoked to explain the strong floristic affinities shared among landmasses in the Southern Hemisphere. Its contribution has not yet been systematically tested because of the previous lack of global data on winds. We used global winds coverage from the National Aeronautics and Space Administration SeaWinds scatterometer to test whether floristic similarities of Southern Hemisphere moss, liverwort, lichen, and pteridophyte floras conform better with (i) the anisotropic LDD hypothesis, which predicts that connection by "wind highways" increases floristic similarities, or (ii) a direction-independent LDD hypothesis, which predicts that floristic similarities among sites increase with geographic proximity. We found a stronger correlation of floristic similarities with wind connectivity than with geographic proximities, which supports the idea that wind is a dispersal vehicle for many organisms in the Southern Hemisphere.

Anisotropy↗
PubMed1992

Cold wind stimulation reflex.

The bradycardia induced by cold wind blown on the face and the early cephalic release of insulin induced by feeding have been shown to be caused by a vagal reflex stimulation. An experiment was designed to determine whether cold wind blown on the face would induce both pancreatic and cardiac stimulation. A 4 degrees C wind blown on the face for 4 min produced a rapid and persistent bradycardia, which interestingly persisted for up to 35 min after the test. The effect on respiration rate is more gradual and vanishes immediately after cold wind stimulation. Cold wind produced a slight reduction of insulin secretion, as evidenced by the fall of both plasma insulin and C-peptide, and caused a significant increase in plasma norepinephrine. These results suggest that the cold wind action of the vagus nerve is exerted on the heart and that of the sympathetic on the pancreas, whereas during the cephalic phase of feeding a vagal influence is observed on the pancreas and a sympathetic action on the heart. The mechanisms of the quantitative and qualitative control of these autonomic responses are not known and deserve further investigation.

Adult↗
PubMed2002

Metabolic response to wind of downy chicks of Arctic-breeding shorebirds (Scolopacidae).

Wind is a significant factor in the thermoregulation of chicks of shorebirds on the Arctic tundra. We investigated the effect of wind at speeds typical of near-surface conditions (0.1-3 ms(-1)) on metabolic heat production, evaporative cooling and thermal conductance of 1- to 3- week-old downy scolopacid chicks (least sandpiper Calidris minutilla; short-billed dowitcher Limnodromus griseus; whimbrel Numenius phaeopus). Body mass ranged from 9 to 109 g. To accurately measure the interacting effects of air temperature and wind speed, we used two or more air temperatures between 15 degrees and 30 degrees C that produced cold stress at all wind speeds, but allowed chicks to maintain normal body temperature (approximately 39 degrees C). Thermal conductance increased by 30-50% as wind speed increased from 0.1 to 3 ms(-1). Conductance in these chicks is somewhat lower than that of 1-day-old mallard ducklings of similar mass, but higher than values reported for downy capercaillie and Xantus' murrelet chicks, as well as for adult shorebirds. Evaporative water loss was substantial and increased with mass and air temperature. We developed a standard operative temperature scale for shorebird chicks. The ratio of evaporative cooling to heat production varied with wind speed and air temperature.

Animals↗
PubMedDate not supplied

Simulated effects of crop rotations and residue management on wind erosion in Wuchuan, west-central Inner Mongolia, China.

For decades, wind erosion has triggered dust and sand storms, buffeting Beijing and areas of northwestern China to the point of being hazardous to human health while rapidly eroding crop and livestock productivity. The EPIC (Environmental Policy Integrated Climate) field-scale simulation model was used to assess long-term effects of improved crop rotations and crop residue management practices on wind erosion in Wuchuan County in Inner Mongolia. Simulation results indicate that preserving crop stalks until land is prepared by zone tillage for the next year's crop in lieu of using them as a source of heating fuel or livestock fodder significantly reduces wind erosion by 60%. At the same time, grain and potato (Solanum tuberosum L.) yields were maintained or improved. Significant reductions in erosion, 35 to 46%, also resulted from delaying stalk removal until late January through late April. Yearly wind erosion was concentrated in April and May, the windiest months. Additionally, the use of alternative crop rotations resulted in differences in wind erosion, largely due to a difference in residue stature and quality and differences in biomass produced. As a result, altering current crop rotation systems by expanding corn (Zea mays L.), wheat (Triticum aestivum L.), and millet [Sorghum bicolor (L.) Moench] and reducing potato and pea (Pisum sativum L.) production significantly reduced simulated wind erosion, thus diminishing the severity of dust and sand storms in northwestern China. Saving and protecting topsoil over time will sustain land productivity and have long-term implications for improving conditions of rural poverty in the region.

Agriculture↗
PubMed1999

Shade and wind barrier effects on summertime feedlot cattle performance.

In each of three summertime trials conducted over consecutive years, approximately 110 predominantly black and black-white-face steers were blocked by weight and randomly allotted to one of 16 pens in a 2x2 factorial arrangement of treatments. Factors consisted of cattle being fed in facilities with or without wind barriers and with or without shade. Steers were fed dry-rolled corn-based diets (1.43 Mcal/ kg, NEg). Mean starting date and days on feed were June 26 and 79, respectively. In unshaded areas, temperature and humidity averaged 21.6 degrees C and 77.9%, and the blackglobe-humidity index (BGHI) at 1500 averaged between 84.0 and 89.1. Each of four 6.1-x6.1-m structures (mean height = 3.4 m) with white steel roofs provided shade (2.65 m2/steer) for two pens. In facilities with wind barriers provided, airflow was reduced from the north and northwest by a 25-m-wide shelterbelt containing six rows of trees. For cattle fed in pens with wind barriers, shade increased (P<.05) gain from 0 to 56 d and decreased (P<.05) DMI/ADG from 0 to 28 d. Differences (P<.05) in performance were not found between shaded and unshaded cattle in any portion of the feeding period for cattle fed in the pens without wind barriers and over the entire feeding period in either type of facility. The shade response in pens with wind barriers seemed to be greater the 1st yr than in subsequent years. Differences in weather patterns among years, especially air temperature, humidity, and solar radiation, may partially explain this interaction. Also, in yr 1, cattle tended to have greater fat thickness at finish than in yr 2 and 3. Correlations between BGHI and DMI tended to be greater during the early portion of the trial (0 to 28 d) than over the entire trial. Correlations between the difference in BGHI under shade vs no shade and percentage of shade use had the greatest magnitude and were significant only in the first 28 d vs over the entire feeding period. Although no heat-related cattle deaths occurred in this study, results suggest that shade improves cattle performance in the summer when they are fed in facilities with winter wind protection available and have not become acclimated to hot conditions. Once cattle are acclimated or hot conditions subside, compensation by unshaded cattle offsets much of the initial benefits of providing shade.

Animal Feed↗
PubMedDate not supplied

Wind velocity effects on sampling rate of NO2 badge.

The effects of wind velocity on a sampling rate of a nitrogen dioxide (NO2) diffusive badge were experimentally determined using a turntable. The use of a turntable permits the collection of the large amounts of data that are needed for statistically reliable results at several wind velocities in one experiment. The regression model for the wind effect determined by these experiments was closely correlated with data previously gathered from experiments using wind tunnels. Experiments at two different relative humidities, 35% and 60%, were performed and analyzed by a simple least square regression model. A multi-regression model containing two independent variables, wind velocity and relative humidity, also was developed. The multi-regression model was useful at relative humidity between 20% and 60% and wind velocity between 0 and 7 meter per second (m/sec).

Air Pollutants↗
PubMed1987

A different approach to wind chill.

In cold regions, "wind chill temperatures" or "wind chill" are regularly used to suggest how the wind-temperature combination may affect comfort or safety. This concept, based on physical studies, is unlikely to provide the most useful information. Humans have no innate temperature sense, and so their response depends not only on physical conditions and physiological state but also on past experience, how they perceive the environment, and how weather conditions differ from the norm. We present wind chill for one north central American city for the winter months and for three north central American communities for the month of February as a frequency table and as it may relate to human perception of cold. We propose that, for any given community, wind-temperature conditions as they may be perceived and how they relate to the norms for that community might add greater meaning to the numerical wind chill temperature.

Air Movements↗
PubMed1993

[Sequential observation on the influence of artificial wind-cold environment to immunologic function of mononuclear phagocytic system in mice].

According to TCM theory of Six Evils, the Wind-Cold is one of the pathogen. In order to find the mechanism of Wind-Cold in causing disease, the effect of subacute Wind-Cold stimulation on the phagocyte immunization in mice was observed. Results showed that through exposing in the Wind-Cold environment, the reticuloendothelial system (RES) clearance function and the hydrogen-peroxide releasing of peritoneal macrophage were suppressed. Sequential observation showed that the peak of immunosuppression occurred on the 3rd day after stimulation and began to normalize at 5th day. These results suggested that Wind-Cold stimulation could inhibit temporary phagocytosis of macrophage and bacteriocidal effect. Action of immunosuppression was believed to be produced by the increase of stress hormone after stimulation. Results also suggested that the pathogenic action of Wind-Cold on disease is somewhat related with the suppression of nonspecific cellular immunity.

Animals↗
PubMed1999

A dynamic model of the behaviour of sitka spruce in high winds

This paper describes the development, verification and use of a mathematical model to describe the dynamic behaviour of typical forest trees in high winds. The model assumes (a) that the trunk can be represented by a vertical tapered cantilever with specified stiffness and mass distributions; (b) that the canopy can be represented by a cylindrical body of a different density at the top of the trunk; (c) that the wind loading can be represented by a spatially constant wind distribution applied to the upper part of the canopy, that is varying in time with realistic spectral properties; (d) that the damping of the oscillations of the tree is caused solely by aerodynamic damping.The resulting complex, fourth-order differential equations are solved using numerical methods. This model is used to predict the transfer functions relating tree displacement spectra to wind spectra, and it is shown that the model is able to represent experimental spectra well, particularly with regard to the prediction of the primary natural frequency. Wind speeds for tree failure by both trunk snapping and uprooting are then pictured, and reasonably realistic values obtained. The need for a better understanding of the relationship between extreme and mean wind gusts is apparent. Through a discussion of the sensitivity of the results to variations in the different model parameters some general conclusions are drawn about the effects of the different parameters on tree stability. Copyright 1999 Academic Press.

Journal Article↗