Operant supplementary heating in groups of growing pigs in relation to air velocity

The aim of the experiments was to investigate the effect of air velocity on the temperature preferred by growing pigs 12–14 weeks old. Pigs displayed a temperature preference by means of operant supplemental heating. They pushed a button connected to heating lamps. Six experiments of three weeks each and with two treatments with a group of 8 pigs each were made. Animals were housed in groups and weighed 14–20 kg at the start of the experiments. Air velocity was 0.08, 0.25 and 0.40 m/s. At each air velocity four replicates were made. Mean temperatures preferred were 17.9°C at 0.08 m/s, 20.5°C at 0.25 m/s and 21.7°C at 0.40 m/s. Within a day temperature preference fluctuated with 5.7 K at 0.08 m/s, 4.3 K at 0.25 m/s and 4.2 K at 0.4 m/s. Temperatures preferred were highest during day time.     

Surface temperatures of growing pigs in relation to the duration of acclimation to air temperature or draught

The aim of this work was to study to what extent surface temperatures of growing pigs are altered during acclimation to a change of the air temperature and to exposure to draught.

4 groups of 10 pigs (Large White × Dutch Landrace) of approximately 10 weeks old were used. They were housed in 2 calorimeters with 2 pens each. In the reference chamber air temperature was kept constant at 25°C, in the other chamber air temperature could be lowered to 15°C, and a draught was also applied. Surface temperatures of the pigs were measured by means of Probey® Thermal Video System, with an accuracy of ±0.3°C.

Surface temperatures of growing pigs were obviously related to air temperature, draught and the duration of food withdrawal. Acclimation to air temperature or draught as measured by surface temperatures was not observed between days, but within and between night periods.

Also indications of huddling, vasocontriction and even cold-induced vasodilatation within the neck, chest and abdomen region of the pigs' body surface were observed.     

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.     

Design and construction of cage environments for air ion and electric field research

This report describes the design and construction of cage environments suitable for chronic exposures of large groups of mice to air ions and electric fields. These environments provide defined and reproducible ion densities, ion flux, DC electric fields, sound levels, air temperature and air quality. When used during a 2 year study, these cage environments served as a durable and reliable continuous exposure system. Three environmental chambers (cubicles) housed a total of 12 cages and provided control of air temperature, air purity and lighting. Exposure cages had grounded metal exterior walls, a plexiglass door and interior walls lined with formica. An internal isolated field plate supplemented with guard wires, energized with ca 1000 VDC, created about a 2 kV/m electric field at the grounded cage floor. Air ions resulted from the beta emission of sealed tritium foils mounted on the field plate. Cages provided high ion (1.3×10⁵ ions/cc), low ion (1.6×10³ ions/cc) and field only (ion depleted < 50 ions/cc) conditions for both polarities with similar electric fields in ionized and field only cages. Detailed mapping of the floor level ion flux using 100 cm² flat probes gave average fluxes of 880 fA cm^–2 in high ion cages and 10 fA cm^–2 in low ion cages. Whole body currents measured using live anesthethized mice in high ion cages averaged 104±63 pA. Both ion flux and whole body currents remained constant over time, indicating no charge accumulation on body fur or cage wall surfaces in this exposure system.     

Superficial contact cryoablation attenuates experimentally created lung air leakage

Previously, we, and others found that cryoablation on normal lung produced localized pulmonary hemorrhage and edema, causing obliteration of air space. Therefore, we hypothesized that lung air leakage may be diminished by this procedure. In the present study, we examined if cryoablation can attenuate experimentally created lung air leakage. Male domestic pigs (n = 4) underwent a thoracotomy. The lung was resected approximately 5 mm in diameter and 1 mm in depth to create air leakage lesions. An argon gas cryoprobe with a copper plate attached to its tip was used to cryoablate the lesions superficially. After cryoablation, the positive airway pressure that produced macroscopic bubbles from each lesion site was compared between cryoablated and untreated lesions. Also, cryoablation of the lung surface was carried out in male Donryu rats (n = 20) which were sequentially sacrificed to observe the histological changes over a time course. In the pigs, the air leakage pressure was significantly increased with cryoablation (40 cmH₂O <) compared to no treatment (19 ± 5 cmH₂O) (p = 0.021, Mann–Whitney U test). Histologically, cryoablation produced acute pulmonary hemorrhage and edema. In the rats, the region with extensive hemorrhage progressed to fibrosis in 1 month, and the areas with edema recovered. This study provides supportive evidence that cryoablation has the potential to stop air leakage from surface pulmonary injury. This procedure may provide a useful adjunct to surgical resection for spontaneous pneumothorax, and the control of air leakage from dissected raw lung surfaces during lung resection.     

Sows’ responses to increased heat load – A review

There is a comprehensive body of literature on how increased air temperature affects the physiology, production and behaviour of sows, while very few studies consider the thermal effects of air humidity and air velocity.This review summarises studies that have investigated effects of air temperature by reviewing published literature in which sows were exposed to at least two different levels of air temperature ranging from 15 °C to 39 °C. Increased rectal temperature was investigated in the majority of the studies (26) and on average, the rectal temperature increased by 0.099 °C per °C increased air temperature above 25 °C. The increase was smaller at lower air temperatures, and it was suggested that rectal temperature is practically unaffected by air temperatures in the range of 15 °C–21 °C. This review elucidates how air temperature also affects performance indicators such as respiration rate, vaginal temperature, skin temperature, feed intake, milk yield, body weight loss during lactation, mortality, litter daily weight gain during lactation and sow behaviour.One study reported how respiration rate, rectal temperature, vaginal temperature and skin temperature were affected by both air temperature and air humidity, and the results suggest that the relative significance of air temperature and humidity may be similar for sows and finishing pigs (e.g. an increase of 40% relative humidity at an air temperature of 30 °C has a similar effect as a 1.9 °C increase in temperature).Studies on mitigation methods against the effects of high temperature and humidity such as snout cooling, drip cooling and floor cooling were reviewed to extract knowledge related to the effects of air velocity, temperatures of surrounding surfaces and the opportunity for sows to moisten their skin.     

Deposition of ammonia to the forest floor under spruce and beech at the Höglwald site

Laboratory and field measurements of the flux of ammonia to forest floor canopies of spruce and beech stands at the Höglwald site in southern Bavaria are reported. Measurements were performed with an open chamber method. A linearity between ammonia concentration and ammonia flux from the atmosphere to the ground floor canopy was detected. Deposition of ammonia showed no saturation even at air concentrations up to 50 g NH₃ m^–3 air. Temperature, water content and the moss layer of the ground floor canopy had a minor influence on the deposition velocity in laboratory experiments. Deposition velocity of ammonia was higher to the spruce (1.3 cm s^–1), and limed spruce ground floor canopy (1.17 cm s^–1) compared to the beech stand (0.79 cm s^–1). In field studies, a diurnal course of the deposition velocity was detected with highest velocities in midday and minor during night times, but not in the climatic chamber. The flux of ammonia to the ground floor canopy was estimated of app. 10 kg N ha^–1 yr^–1 for the soil under spruce, 9 kg N ha^–1 yr^–1 for the limed spruce and 6 kg N ha^–1yr^–1 for the soil under beech. The fluxes are interpreted as fluxes from the atmosphere to the ground canopies of the stands.     

Longitudinal study of the contamination of air and of soil surfaces in the vicinity of pig barns by livestock-associated methicillin-resistant Staphylococcus aureus

During 1 year, samples were taken on 4 days, one sample in each season, from pigs, the floor, and the air inside pig barns and from the ambient air and soil at different distances outside six commercial livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA)-positive pig barns in the north and east of Germany. LA-MRSA was isolated from animals, floor, and air samples in the barn, showing a range of airborne LA-MRSA between 6 and 3,619 CFU/m(3) (median, 151 CFU/m(3)). Downwind of the barns, LA-MRSA was detected in low concentrations (11 to 14 CFU/m(3)) at distances of 50 and 150 m; all upwind air samples were negative. In contrast, LA-MRSA was found on soil surfaces at distances of 50, 150, and 300 m downwind from all barns, but no statistical differences could be observed between the proportions of positive soil surface samples at the three different distances. Upwind of the barns, positive soil surface samples were found only sporadically. Significantly more positive LA-MRSA samples were found in summer than in the other seasons both in air and soil samples upwind and downwind of the pig barns. spa typing was used to confirm the identity of LA-MRSA types found inside and outside the barns. The results show that there is regular airborne LA-MRSA transmission and deposition, which are strongly influenced by wind direction and season, of up to at least 300 m around positive pig barns. The described boot sampling method seems suitable to characterize the contamination of the vicinity of LA-MRSA-positive pig barns by the airborne route.     

The effect of long or chopped straw on pig behaviour

In the EU, pigs must have permanent access to manipulable materials such as straw, rope, wood, etc. Long straw can fulfil this function, but can increase labour requirements for cleaning pens, and result in problems with blocked slatted floors and slurry systems. Chopped straw might be more practical, but what is the effect on pigs’ behaviour of using chopped straw instead of long straw? Commercial pigs in 1/3 slatted, 2/3 solid pens of 15 pigs were provided with either 100 g/pig per day of long straw (20 pens) or of chopped straw (19 pens). Behavioural observations were made of three focal pigs per pen (one from each of small, medium and large weight tertiles) for one full day between 0600 and 2300 h at each of ~40 and ~80 kg. The time spent rooting/investigating overall (709 s/pig per hour at 40 kg to 533 s/pig per hour at 80 kg), or directed to the straw/solid floor (497 s/pig per hour at 40 kg to 343 s/pig per hour at 80 kg), was not affected by straw length but reduced with age. Time spent investigating other pigs (83 s/pig per hour at 40 kg), the slatted floor (57 s/pig per hour) or pen fixtures (21 s/pig per hour) was not affected by age or straw length. Aggressive behaviour was infrequent, but lasted about twice as long in pens with chopped straw (2.3 s/pig per hour at 40 kg) compared with pens with long straw (1.0 s/pig per hour at 40 kg, P=0.060). There were no significant effects of straw length on tail or ear lesions, but shoulders were significantly more likely to have minor scratches with chopped straw (P=0.031), which may reflect the higher levels of aggression. Smaller pigs showed more rooting/investigatory behaviour, and in particular directed towards the straw/solid floor and the slatted floor than their larger pen-mates. Females exhibited more straw and pen fixture-directed behaviour than males. There were no effects of pig size or sex on behaviour directed towards other pigs. In summary, pigs spent similar amounts of time interacting with straw/solid floor when long and chopped straw were provided, and most aspects of pig-directed behaviour and injuries were not affected by straw length. There was an increase in pigs with minor shoulder lesions with chopped straw, perhaps because of increased aggression. The use of chopped straw as an enrichment material for pigs warrants further investigation in larger and more detailed studies.     

Opportunistic fungi in soils and surface air of a megalopolis (for the Tushino Region,Moscow)

The number and composition of opportunistic microscopic fungi was studied in soils and surface air (0.2 and 1.5 m above the surface) in the megalopolis districts (Tushino, Moscow) of different age of construction (6 and 40 years) and in urban recreational forests. The highest number (up to 1500 CFU/m³) determined by plating from air was found in the summer in new-built quarters. Direct count of fungal diaspores in airborne dust yielded significantly higher values (up to 4 × 10⁵/m³). The composition of the soil fungal population differed significantly from that of the air. In soil, the diversity of potentially pathogenic fungi was higher, while in air, their abundance was greater. The highest content of opportunistic fungi in soil and air was observed in spring and late summer-autumn, respectively. The fungi known as allergenic (mostly Cladosporium spp.) predominate in the air in autumn, especially in the new-built quarters.     

Total bacterial number concentration in free tropospheric air above the Alps

Over a period from June to October 2010, we carried out four short campaigns on the northern alpine ridge (High Altitude Research Station Jungfraujoch, 3,450 m above sea level) to determine bacterial number concentrations by collecting aerosol with liquid impingers, followed by filtration, fluorescent staining and counting with a microscope. Impinger liquid was also subjected to drop freeze tests to determine the number of ice nucleators. Parallel measurements of ²²²Rn enabled us to distinguish air masses with no, or little, recent land surface contact (free troposphere, ²²²Rn ≤ 0.50 Bq m^?3) from air masses influenced by recent contact with land surface (²²²Rn > 0.50 Bq m^?3). In free tropospheric air, concentration of total bacteria was on average 3.4 × 10⁴ cells m^?3 (SD = 0.8 × 10⁴ cells m^?3). When wind conditions preceding sampling were calm, or when the station was in clouds during sampling, there was no detectable difference in bacterial number concentrations between free tropospheric air and air influenced by recent land surface contact. One campaign was preceded by a storm. Here, recent land surface contact had enriched the air in bacterial cells (up to 7.5 × 10⁴ cells m^?3). Very few of these bacteria may act as ice nucleators in clouds. The median ratio of ice nucleators to the number of bacterial cells in our study was 1.0 × 10^?5. We conclude that injection of bacterial cells into the free troposphere is an intermittent process. Conditions controlling the release of bacteria into near surface air are probably more of a limiting factor than vertical transport and mixing of near surface air into the free troposphere.     

Effects of air movement on swine at high temperature

Sixty pigs were used to study the effects of air movement (0.05, 0.5, and 1.0 m/s) at constant air temperatures of either 5.6 or 11.1°C above optimum, and at 3 different weight ranges (36–50kg, 54–68 kg, and 73–86 kg) during the growing-finishing stages. An air velocity of 0.5 m/s produced significantly greater weight gain and feed conversion than did 0.05 m/s. An air velocity of 1.0 m/s produced intermediate results.     

Importance of inlet air velocity in fluid bed dyring of a granulation prepared in a high shear granulator

Conclusions  This report shows that inlet air velocity can play a critical role in maintaining proper fluidization and, ultimately, uniform drying. The mechanism by which air velocity affects fluidization has been discussed by various researchers [4–5]. An indication of good fluidization is a free downward flow of the granules at the sight glass of the drying bowl, but such limited observation could be misleading. In such cases, the exhaust air temperature can be used to detect poor fluidization. If the exhaust air temperature rises more rapidly than anticipated, as seen with process 1 (Figure 1), it is an indication that fluidization is incomplete. In conclusion, a fundamental understanding of the mechanism of fluidization by inlet air will help in the development of a fluid bed drying process that produces uniformly dried granules and minimizes the number of process problems encountered.     

Effects of dry air and subsequent humidification on tracheal mucous velocity in dogs.

The impairment of mucociliary transport by dry air breathing and the restoration of function with subsequent humidification of inspired air were investigated in anesthetized dogs. Tracheal mucous velocity was measured by a cinebronchofiberscopic technique. The breathing of dry air through an uncuffed endotracheal tube produced almost complete cessation of the flow of tracheal mucus after 3 h. Subsequent breathing of air at 38 degrees C with 100% relative humidity restored tracheal mucous velocity to control values by the end of and additional 3 h. Histologic examination of the trachea at the end of the 3-h dry air breathing period revealed focal areas of sloughing of the ciliated epithelium and submucosal inflammation. Although morphometry was not employed, the inflammatory changes appeared to have progressed during 3 h of breathing fully humidified air subsequent to the dry air breathing period. These findings were consistent with previous reports that the inflammatory response to injury of the tracheobronchial mucosa might be delayed and that the mucociliary transport system has a great deal of functional reserve. We found that an artificial heat and moisture exchanger placed on the proximal end of an endotracheal tube partially protects against the suppression of tracheal mucous velocity caused by dry air breathing.     

Heat induced infertility of boars: The inter-relationship between depressed sperm output and fertility and an estimation of the critical air temperature above which sperm output is impaired

Eight groups of Large-White gilts were each inseminated with different numbers of normal motile sperm, in the range 0.28–7.0 × 10⁹. A significant (P < 0.05) relationship between conception rate and the number of motile sperm inseminated was shown. This relationship can be used to equate output of motile sperm with levels of fertility of boars. The optimal number of motile sperm for conception following intra-cervical insemination was near 5 × 10⁹ and the threshold number, below which animals did not conceive, was c. 4 × 10⁸.In a second experiment, three Large-White boars were subjected to graded thermal treatment (air temperature was increased by 1°C per day for 20 days, from a basal level of 20°C to a maximal level of 40°C) and responses of ejaculate and other physiological characteristics were monitored. Scrotal surface temperature, respiration rate and rectal temperature increased (P < 0.05) beyond basal levels at air temperatures of 30°C, 33°C and 35°C, respectively. Motility of sperm in ejaculates decreased when air temperature reached 30°C and this response was presumed to reflect hyperthermia in epididymal tissues, consistent with increasing scrotal surface temperature at this same air temperature. Motility fell below a pre-treatment level of about 93%, to 19% (P < 0.05), 3 weeks after heating. Volumes of seminal plasma and gel in ejaculates were also lower (P < 0.05) following heating. Changes in daily sperm production were minor and, as a result, daily motile sperm production levels paralleled changes in motility. Proportions of abnormal types of sperm increased (P < 0.05) to maximal levels in the last week of heating and all returned to pretreatment values 5 weeks later. High proportions of sperm with kinoplasmic droplets appeared in ejaculates collected after heating (P < 0.05), evidence that epididymal cell types in the boar are sensitive to heat.As a result of heat treatment, normal motile sperm production decreased from control levels (1.28 × 10¹⁰·day^?1) to 0.15 × 10¹⁰·day^?1, 3 weeks after heating ceased. However, the results suggest that normal sperm output by Large-White boars can be maintained at air temperatures as high as 29°C.By relating the results of both experiments, it is concluded that fertility of the boars in the second experiment (if mated once daily) would be depressed for about 5 weeks after heat treatment ceased. The findings support many field reports which indicate a contribution of boars to lower conception rates of sows during and immediately following summer and the results can be used in formulating strategies to circumvent this widespread problem.     

The effect of air velocity on the wingstroke frequency of the blowflyCalliphora erythrocephala

Summary The effect of air velocity and pressure on the wingstroke frequency ofCalliphora erythrocephala, flying in a windtunnel, was studied. The results can be understood by considering the flight mechanism as a mechanical oscillator with an inertia, that depends on air velocity and pressure, without any need for nervous control.The effect of changes in air velocity on the wingstroke frequency was calculated, taking the inertia of a steady two-dimensional boundary layer around the wings as the variable part of the inertia of the flight mechanism. The calculated effect was ten times smaller than that observed experimentally. The reason for this discrepancy is discussed.     

Biotrickling air filtration of 2-chlorophenol at high loading rates

The degradation of 2-chlorophenol vapours in air was performed in a trickling biofilter packed with ceramic material seeded with the bacterium Pseudomonas pickettii, strain LD1. The system performance was evaluated under varying operating conditions (inlet 2-chlorophenol air concentrations from 0.10 to 3.50 g m^?3, and superficial air velocities of 30.0, 60.0, and 120.0 m h^?1). For all air velocity the maximum degradation rate was obtained for loading rates of 40 g m^?2 h^?1. Higher loading conditions resulted in strong inhibition of microbial activity, particularly severe at high air velocity. Process analysis, performed using data on pollutant concentration profiles along the filter packing obtained under different conditions of inlet concentration and air velocity, proves that best performance (i.e. maximum degradation efficiency and capacity) can be obtained for a narrow range of operating conditions, which can be ensured by proper design of biofilter size (i.e. diameter and height). Kinetic analysis of experimental data confirms that 2-CP inhibits microbial activity in the biofilter bed. Experimental data are satisfactorily fitted by the Haldane kinetic equation up to a critical value of loading rate, beyond which the experimental degradation rate is overestimated by the kinetic model. The inhibition appears to be affected by the loading rate, and the estimated inhibition constant linearly increases with increasing empty bed residence time.     

Plant growth chambers for the simultaneous control of soil and air temperatures, and of atmospheric carbon dioxide concentration

Many facilities for growing plants at elevated atmospheric concentrations of CO₂ ([CO₂]) neglect the control of temperature, especially of the soil. Soil and root temperatures in conventional, free-standing pots often exceed those which would occur in the field at a given air temperature. A plant growth facility is described in which atmospheric CO₂ can be maintained at different concentrations while soil and air temperatures mimic spatial and temporal patterns seen in the field. It consists of glasshouse-located chambers in which [CO₂] is monitored by an infra-red gas analyser and maintained by injection of CO₂ from a cylinder. Air is cooled by a heat exchange unit. Plants grow in soil in 1.2 m long containers that are surrounded by cooling coils and thermal insulation. Both [CO₂] and temperature are controlled by customized software. Air temperature is programmed to follow a sine function of diurnal time. Soil temperature at a depth of 0.55 m is programmed to be constant. Temperature at 0.1 m depth varies as a damped, lagged function of air temperature; that at 1.0 m as a similar function of the 0.55 m temperature. [CO₂] is maintained within 20 μmol mol^?1 of target concentrations during daylight. A feature of the system is that plant material is labelled with a ¹³C enrichment different from that of carbon in soil organic matter. The operation of the system is illustrated with data collected in an experiment with spring wheat (Triticum aestivum L., cv Tonic) grown at ambient [CO₂] and at [CO₂] 350 μmol mol^?1 greater than ambient.     

Activity in Heodes virgaureae (Lep., Lycaenidae) in relation to air temperature,solar radiation,and time of day

Summary The degree of activity of H. virgaureae in the field is largely dependent on air temperature, solar radiation, and wind velocity. Solar radiation increases body temperature above ambient. The butterfly orientates its back towards the sun and exposes the dorsal surface of the wings. At high temperatures they close the wings thereby minimizing the surface exposed to the sun. The optimal body temperature lies around 35°C as was indicated by laboratory experiments. In cloudy and cool to fairly warm conditions the butterfly is inactive. In sunshine the butterfly basks at low radiation intensities or low air temperatures while feeding (in males also flying) predominates at full sunshine or very high air temperatures (around 30°C). Males fly 5–10 times as much as females. A change from unfavourable to favourable weather is followed by an immediate increase in activity of the butterfly, which enables the butterfly to utilize short periods of sunshine.     

Selection of bedded and unbedded areas by pigs in relation to environmental temperature and behaviour

In 2 experiments, groups of 3 pigs aged 4–8 weeks were given access to 2 sides of an experimental pen, one with straw bedding and one with a bare concrete floor. When resting or feeding, the 12 groups in Experiment 1 showed no consistent preference for the bedded or unbedded side. When active, the pigs were more often on the bedded side, especially at times when fresh straw was provided. The quantity of straw had no effect on these trends.In the second experiment, 10 groups tested at an ambient temperature of 18–21°C strongly selected the bedded side for resting, while those tested at 25–27°C usually selected the bare concrete. Feeding and general activity showed no clear relation to floor type. At the cooler temperatures, most groups dunged on the side that was not used for resting and feeding, but this structuring of the living space was not so apparent at the higher temperatures.The results indicate that the animals' preference for a bedded or concrete floor depends strongly on temperature. Under warm conditions, straw is likely to benefit pigs because of its recreational value but not as a means of improving comfort in the resting area.