A climate room for precise regulation of temperature and humidity in connection with a temperature-regulated nest site for wood ants

Summary A climate room is described for precise regulation of temperature and humidity. Humidity is regulated by regulation of the dew-point temperature of the air. The ranges for both dew-point and air temperature are from 2°C to 45°C. The precision of regulation for the temperature is ±0.05°C, for the dew-point temperature ±0.1°C. In the climate room very homogeneous temperatures can be obtained (±0.1°C). The relative humidity is homogeneous within ±1%.It is also possible to make air temperature different from floor temperature. The dimensions of the experimental room are 200×50×17 cm.A temperature-regulated nest site for Red Wood Ants is also described.     

Effect of space allowance and earthen flooring on behaviour of farmed blue foxes

This study sought to evaluate the effect of cage space and earthen flooring on the behaviour of individually caged, farmed blue foxes (Alopex lagopus). Three different cage sizes [80 cm long (CL80), 120 cm long (CL120), 240 cm long (CL240); each 105 cm wide×70 cm high] with wire-mesh flooring, and one two-level cage (CL240E) with both wire-mesh (240 cm long×105 cm wide×70 cm high) and earthen flooring (80 cm long×105 cm wide×70 cm high) were employed. Quantitative ethograms were obtained from ten males in each group by videotaping the animals for 144 h monthly from August through November. Altogether 30 different behaviours were described. These were rather similar in all study groups. Examples of behavioural differences included pacing around with a neighbour and the incidence of scratching, which both declined with increasing cage space. Only the foxes in the cage with an earthen flooring (CL240E) exhibited digging behaviour, which averaged 11 min/24 h. The wire-mesh section was distinctly preferred to the earthen-floor section for most behaviours. Foxes in all groups were at their most active from 0800 to 1600 hours. Total activity, including several separate behaviours, declined as winter approached. Locomotor and oral stereotypies were infrequent, and no significant differences were found between the various cage options. For several hours before feeding, the foxes showed increasing levels of stereotypies, but afterwards, stereotypies abruptly declined. Received in revised form: 28 March 2001 Electronic Publication     

LEAF SURFACE WETNESS AND GAS EXCHANGE IN THE POND LILY NUPHAR POLYSEPALUM (NYMPHAEACEAE)

As part of a continuing study of the effects of leaf surface wetness on gas exchange, the occurrence of leaf surface wetting by dewfall and associated effects on photosynthesis were evaluated for floating and aerial leaves of the pond lily Nuphar polysepalum Engelm. Because of nighttime radiation exchange with a cold sky, high humidity, and the presence of adaxial stomata, we predicted that pond lily leaves would be particularly susceptible to wetting events such as dewfall. A substantial reduction in net photosynthesis (up to 20%) occurred for leaves that were experimentally misted to simulate leaf wetting by dewfall. Aerial leaves remained below dewpoint temperatures for long periods on clear nights. However, floating leaves rarely approached dewpoint temperatures at night because minimum nighttime temperatures of leaves were up to 10 C warmer than air temperature. Thus, floating leaves of N. polysepalum did not experience dew formation primarily because of strong thermal coupling to a substrate (water) that was much warmer than air temperature at night. This coupling to a warmer substrate prevented a potentially strong inhibition of photosynthetic CO₂ exchange the following morning.     

The effects of cage size and pair housing on exercise of beagle dogs

One of the requirements of the 1985 amendments to the Animal Welfare Act is the establishment of an exercise program for dogs. Assumptions have been made by some that larger cages or the presence of a companion animal will motivate exercise. To examine how cage size, pair housing and human contact affect exercise, a study was conducted using a computerized video-data acquisition system that measured distance traveled and time spent moving in 1 x 1 m, (single only) and 1 x 2 m (single and paired) and 1 x 1.5 m cage (paired only) cages. Male beagle dogs (n = 6) housed singly in the 1 m2 cage traveled an average of 55 m/hr spending only 8% (57 min) of the 12 h photo period in motion. When the cage size was doubled, the average distance traveled decreased to 13 m/hr and the time spent moving increased to 11% (77 min/day). When dogs were pair housed in a regulation size cage, the average distance traveled decreased to 8.6 m/hr and they spent less than 6% of the day in exercising (42 min/12 hrs). The greatest amount of exercise was seen when dogs were housed as a pair in a cage less than recommended size (an average of 109 m/hr and 8.8 min/hr). Therefore, these data indicate that larger cages or pair housing in regulation size cages have little or no effect on the activity of purpose bred male beagle dogs. There was, however, a direct correlation between activity, time and distance, and the presence of humans in the animal room.(ABSTRACT TRUNCATED AT 250 WORDS)     

Temperature and irradiance and the total daily photosynthetic production of the crown of a Pinus radiata tree

Summary Carbon dioxide exchange rates were recorded for different ages and positions of foliage and parts of the main stem of a 7-m tall Pinus radiata D. Don tree growing in a large, artificially lit, controlled-environment room. Irradiance levels were varied from dark to approximately full sunlight, and air temperatures from 10° to 35°C in 5°C steps. Leaf temperatures within the cuvettes used for CO₂ exchange measurements, however, were up to 5°C higher than the room air temperature set but this varied with position in the tree crown, the shaded lower crown being at approximately room temperature. A balance sheet was prepared to show the photosynthetic gains and respiratory losses of different parts of the crown over 24 h at each air temperature and at irradiances of 400, 270, and 135 W m^-2 during the 8-h photosynthetic period. The greatest daily photosynthetic gain was at 10° C, although this temperature is considered sub-optimal for growth. At temperatures greater than 25° C, even at the greatest irradiance level for 8 h, total respiration was greater than photosynthesis.     

Measurement of airborne fungal spore dispersal from three types of flooring materials

Research was conducted in an experimental roomto measure the effect of human activity onairborne dispersal of settled fungal sporesfrom carpet and vinyl tile flooring. A seriesof experiments were conducted in whichcommercial loop pile carpet, residential cutpile carpet, or vinyl tile installed in theexperimental room were contaminated with Penicillium chrysogenum spores. The flooringmaterials were contaminated to two differentlevels (10⁶ and 10⁷ colony formingunits per square meter [c.f.u./m²] offlooring surface). Airborne culturable andtotal P. chrysogenum concentrations weremeasured using Andersen single-stage impactorsamplers and Burkard personal slide impactorsamplers, respectively. Bioaerosolconcentrations were measured at floor level, 1meter, and the adult breathing zone (1.5 meter)heights before and after human activityconsisting of walking in a prescribed patternfor 1 minute in the room. Airborne P.chrysogenum concentrations were greater withthe higher surface loading for all threeflooring materials. For all flooring materialsthere was no significant difference betweensampler locations, although the data from the1-meter location were the highest, followed bythe floor level and the breathing zonelocations, respectively. The data from theseexperiments indicate that while a very smallfraction of culturable P. chrysogenumspores present on flooring materials wereaerosolized by walking, relatively highairborne concentrations of spores maybere-entrained from contaminated materials. Theairborne P. chrysogenum concentrationswere significantly higher after walking on cutpile carpet than with the other two flooringmaterials at both contamination levels, withthe differences in concentration often 2orders of magnitude. No differences weremeasured in airborne culturable P.chrysogenum between vinyl flooring and looppile carpet at both contamination levels. Total spore data from the experiments with the10⁷ c.f.u./m² contamination levelindicated that walking on loop pile carpetproduced higher airborne spore concentrationsthan similarly contaminated vinyl tile althoughno significant difference was observed at the10⁶ c.f.u./m² level.     

Enhanced detection of surface-associated bacteria in indoor environments by quantitative PCR

Methods for detecting microorganisms on surfaces are needed to locate biocontamination sources and to relate surface and airborne concentrations. Research was conducted in an experimental room to evaluate surface sampling methods and quantitative PCR (QPCR) for enhanced detection of a target biocontaminant present on flooring materials. QPCR and culture analyses were used to quantitate Bacillus subtilis (Bacillus globigii) endospores on vinyl tile, commercial carpet, and new and soiled residential carpet with samples obtained by four surface sampling methods: a swab kit, a sponge swipe, a cotton swab, and a bulk method. The initial data showed that greater overall sensitivity was obtained with the QPCR than with culture analysis; however, the QPCR results for bulk samples from residential carpet were negative. The swab kit and the sponge swipe methods were then tested with two levels of background biological contamination consisting of Penicillium chrysogenum spores. The B. subtilis values obtained by the QPCR method were greater than those obtained by culture analysis. The differences between the QPCR and culture data were significant for the samples obtained with the swab kit for all flooring materials except soiled residential carpet and with the sponge swipe for commercial carpet. The QPCR data showed that there were no significant differences between the swab kit and sponge swipe sampling methods for any of the flooring materials. Inhibition of QPCR due solely to biological contamination of flooring materials was not evident. However, some degree of inhibition was observed with the soiled residential carpet, which may have been caused by the presence of abiotic contaminants, alone or in combination with biological contaminants. The results of this research demonstrate the ability of QPCR to enhance detection and enumeration of biocontaminants on surface materials and provide information concerning the comparability of currently available surface sampling methods.     

Comparative physiological responses of normotensive and essentially hypertensive men to exercise in the heat

Six essentially hypertensive men (average resting arterial pressure of 150/97 mm Hg) and eight normotensive controls (average resting arterial pressure of 115/73 mm Hg) were tested during 1 h of dynamic leg exercise in a warm environment. The groups were well matched for age, VO2 max, body surface area, weight, and body fat. Environmental conditions were 38 degrees C dry-bulb, 28 degrees C wet-bulb; exercise intensity was approximately 40% VO2 max (85-90 W). There were no significant intergroup differences in core or mean skin temperatures, calculated heat exchange variables, heart, or sweat rates. Blood pressure differences between the groups were maintained (P less than 0.01). The hypertensive group responded with a significantly lower stroke index (P less than 0.01) and cardiac index (P less than 0.01), and a decreased slope of the rise in forearm blood flow (P less than 0.01) due to an higher vascular resistance (P less than 0.01). The combined heat load (M + R + C) presented was not sufficient to override the hypertensives' higher cutaneous vasoconstrictor tone. However, on a practical basis, the hypertensives were able to tolerate exercise in the heat as well as their normotensive counterparts.     

Sweat gland response to local heating during sleep in man

In order to assess whether the fluctuations in the sweating response occurring during sleep are related to changes in central drive or in peripheral sweat gland reactivity, 4 healthy male subjects spent 6 non-consecutive nights in a climatic chamber. Air temperature was 25 degrees C, dew-point temperature was 10 degrees C and air velocity was 0.3 m X s-1, while wall temperature was either 38 degrees C, 46 degrees C or 48.7 degrees C giving 3 levels of operative temperature (To = 30, 33 or 34 degrees C). During the whole night, 2 local sweating rates on the right and the left sides of the upper chest were continuously recorded from 12 cm2 area capsules using a dew-point hygrometer technique, while applying local thermal clamps, a constant 2 degrees C difference in local skin temperatures being imposed between the two symmetrical skin areas. Continuous measurements were made of rectal temperature, 10 local skin temperatures, 2 EEGs, 2 EOGs, 1 EMG and 1 ECG. Results show that the multiplicative relationship between the peripheral influence of local skin temperature and the central drive for sweating described in waking subjects, is still valid in sleeping subjects. No peripheral change appears in sweat gland reactivity between the different sleep stages. Changes in the sensitivity of the thermoregulatory system occurring during sleep cannot be explained by a local factor acting at the sweat gland level.     

The effect of gravity on surface temperatures of plant leaves

A fundamental study was conducted to develop a facility having an adequate air circulation system for growing healthy plants over a long-term under microgravity conditions in space. To clarify the effects of gravity on heat exchange between plant leaves and the ambient air, surface temperatures of sweet potato and barley leaves and replica leaves made of wet paper and copper were evaluated at gravity levels of 0.01, 1.0, 1.5 and 2.0 g for 20 s each during parabolic aeroplane flights. Thermal images were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 18% and an irradiance of 260 W m-2. Mean leaf temperatures increased by 0.9-1.0 degrees C with decreasing gravity levels from 1.0 to 0.01 g and decreased by 0.5 degrees C with increasing gravity levels from 1.0 to 2.0 g. The increase in leaf temperatures was at most 1.9 degrees C for sweet potato leaves over 20 s as gravity decreased from 1.0 to 0.01 g. The boundary layer conductance to sensible heat exchange decreased by 5% when the gravity decreased from 1.0 to 0.01 g at the air velocity of 0.2 m s-1. The decrease in the boundary layer conductance with decrease in the gravity levels was more significant in a lower air velocity. Heat exchange between leaves and the ambient air was more retarded at lower gravity levels because of less sensible and latent heat transfers with less heat convection.     

Local sweating responses of different body areas in dehydration-hydration experiments

Five subjects performed intermittent exercise on a bicycle ergometer (25 min work, 5 min rest cycles for 2 hours, and 20 min work, 10 min rest cycles for a further hour) in a hot environment (air and wall temperatures = 36 degrees C; dew-point temperature = 10 degrees C; air velocity = 0.6 m.s-1). The relative mechanical work load was of 70 W (30% of the maximal aerobic capacity). Seven experimental tests were carried out in order to induce a plasma hypovolemia associated with either a plasma hypo- or hyperosmolarity. The preexercise level of body hydration was also manipulated by giving a diuretic, or by ingestion of 500 ml of isotonic electrolyte sucrose solution before the start of exercise. Continuous measurements were made of rectal and mean skin temperatures. The sweating responses of the chest and of the thigh (over the active muscles of the leg) were monitored from 4 sweat collection capsules highly ventilated. On each of these body areas, the local skin temperatures under one of the 2 capsules was kept at a constant level (37 degrees C). The effects of the level of body hydration on the sweating response only appear when a high local thermal clamp is imposed beneath the capsule. This local effect is particularly strong over the active muscles of the thigh. The influence of the preexercise hydration appears during dehydration tests. This effect is not significant when fluid is given to the subject during the exercise. The change in the sensitivity of the thermoregulatory system is more strongly associated with plasma osmolarity than hypovolemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enhanced Detection of Surface-Associated Bacteria in Indoor Environments by Quantitative PCR

Methods for detecting microorganisms on surfaces are needed to locate biocontamination sources and to relate surface and airborne concentrations. Research was conducted in an experimental room to evaluate surface sampling methods and quantitative PCR (QPCR) for enhanced detection of a target biocontaminant present on flooring materials. QPCR and culture analyses were used to quantitate Bacillus subtilis (Bacillus globigii) endospores on vinyl tile, commercial carpet, and new and soiled residential carpet with samples obtained by four surface sampling methods: a swab kit, a sponge swipe, a cotton swab, and a bulk method. The initial data showed that greater overall sensitivity was obtained with the QPCR than with culture analysis; however, the QPCR results for bulk samples from residential carpet were negative. The swab kit and the sponge swipe methods were then tested with two levels of background biological contamination consisting of Penicillium chrysogenum spores. The B. subtilis values obtained by the QPCR method were greater than those obtained by culture analysis. The differences between the QPCR and culture data were significant for the samples obtained with the swab kit for all flooring materials except soiled residential carpet and with the sponge swipe for commercial carpet. The QPCR data showed that there were no significant differences between the swab kit and sponge swipe sampling methods for any of the flooring materials. Inhibition of QPCR due solely to biological contamination of flooring materials was not evident. However, some degree of inhibition was observed with the soiled residential carpet, which may have been caused by the presence of abiotic contaminants, alone or in combination with biological contaminants. The results of this research demonstrate the ability of QPCR to enhance detection and enumeration of biocontaminants on surface materials and provide information concerning the comparability of currently available surface sampling methods.     

Association between weather conditions and the number of patients at the emergency room in an Argentine hospital

The aim of this paper is to study the relationships between hospital emergencies and weather conditions by analysing summer and winter cases of patients requiring attention at the emergency room of a hospital in the city of Buenos Aires, Argentina. Hospital data have been sorted into seven different diagnostic groups as follows: (1) respiratory, cardiovascular and chest-pain complaints; (2) digestive, genitourinary and abdominal complaints; (3) neurological and psychopathological disorders; (4) infections; (5) contusion and crushing, bone and muscle complaints; (6) skin and allergies and (7) miscellaneous complaints. In general, there is an increase of 16.7% in winter while, for group 2 and group 6, there are more patients in summer, 54% and 75% respectively. In summer, the total number of patients for group 6 shows a significant positive correlation with temperature and dew-point temperature, and a negative correlation with the sea-level pressure for the same day. In winter, the same relationship exists, however its correlation is not as strong. The lags observed between these three variables: maximum dew-point temperature, maximum temperature, minimum air pressure and the peaks in admissions are 1, 2 and 4 days respectively. In winter, increases in temperature and dew point and decreases in pressure are followed by a peak in admissions for group 2. In winter, there are significantly more cases in group 5 on warm, dry days and on warm, wet days in the summer.     

Molecular dynamics simulation of replacement of methane hydrate with carbon dioxide

Molecular dynamics simulation was performed to analyse the phenomena of replacement of methane hydrate with carbon dioxide (CO₂) at 270 K and 5.0 MPa for 5300 ps. The methane hydrate phase was constructed with 16 unit cells of hydrate. Every cage in the hydrate was occupied by one methane molecule. The methane hydrate phase was sandwiched between two CO₂ phases. During the simulation the hydrate partially melted and liquid water phase appeared, and CO₂ dissolved in the liquid water phase. The replacements were observed three times at the hydrate–liquid water interface during the simulation. In the first case, the replacement occurred at a S-cage without changing the structure. In the second case, an M-cage of methane hydrate partially collapsed, and methane and CO₂ molecules exchanged. After the exchange, the cage occupied by CO₂ remained in the M-cage structure. In the third case, a S-cage of methane hydrate partially collapsed, and methane and CO₂ molecules exchanged. After the exchange, the cage occupied by CO₂ changed to an M-cage-like structure.     

The meteorological sensitivity of ischaemic heart disease mortality events in Birmingham, UK

Winter ischaemic heart disease (IHD) mortality events (ME) were identified in order to establish their degree of meteorological sensitivity. Sensitivity was evaluated using regression of surface meteorological and large-scale atmospheric circulation variables on daily mortality for each mortality event. Critical meteorological variables affecting IHD mortality appear to be local surface dry-bulb and dew-point temperature and large-scale southerly and westerly wind components, atmospheric pressure and vorticity. The rate of change and departure from normal conditions of these variables appear to be especially important for engendering IHD mortality events. Associated with IHD mortality are two broad types of weather conditions: (1) blustery westerly flows and rapidly changing weather from the west and (2) climatologically strong northeasterly to southeasterly flows of cold air, which bring rapidly changing and anomalous thermal conditions to the study area. The general atmospheric circulation patterns that produce these conditions are identified and the implications of results for weather and health studies are discussed. Received: 24 October 2000 / Revised: 16 April 2001 / Accepted: 18 April 2001     

Habitat ecology of southern African quartz fields: studies on the thermal properties near the ground

Desert pavements of white quartz stones (quartz fields) represent azonal habitats in several arid regions of southern Africa. The vegetation of these quartz fields is characterised by dwarf and highly succulent growth forms which contrast strongly with the shrubby vegetation of the surroundings. Incoming and reflected global solar radiation, air temperature near the ground, soil-surface temperatures and leaf-surface temperatures of dwarf plants were determined under natural habitat conditions inside and outside of the quartz fields. Surface temperatures of quartz and shale stones were compared. The study was conducted in the Kners-vlakte and the Little Karoo (Succulent-Karoo Biome), South Africa. The daily maximum temperatures of the air near the ground of quartz fields was several degrees lower than the air near the ground of neighbouring soils without quartz cover. Maximum soil-surface temperatures of the quartz fields, however, were only lower in summer. Accordingly, the leave surfaces of dwarf plants (Aizoaceae) growing inside quartz fields were up to 3 K cooler than identical plants outside the quartz fields. The lower maximum temperatures is associated with an about 5% higher reflection of quartz fields compared to neighbouring soils without quartz cover. At night, the minimum temperatures of the air near the ground and the soil surface temperatures on quartz fields were above those of soils without quartz cover. The nocturnal surface temperatures of quartz stones did not differ considerably from that of shale and often ranged above the temperatures and dew-point of the ambient air. Consequently, the relatively cooler quartz fields seem to provide less adverse growing conditions for plants near the ground compared to surrounding soils without quartz cover. This revised version was published online in August 2006 with corrections to the Cover Date.     

Structure and hydration of purple membranes in different conditions

The unit cell dimension of the bacteriorhodopsin lattice in purple membranes decreases by the same amount (2%) upon drying the membranes at room temperature as when they are cooled to liquid nitrogen temperatures. Neutron diffraction experiments with H2O:2H2O exchange, however, show that whereas in the dry membranes the lipid headgroups are dehydrated and the decrease in dimension is due to a smaller area occupied by the lipid molecules, the water of hydration remains in place in the cooled membranes, and the decrease in dimension is due to thermal contraction only. These data suggest a hypothesis that functional bacteriorhodopsin, in the wet state at room temperature, has a relatively soft environment that would allow large amplitude motions of the protein; in the dry membranes at room temperature (which are inactive), the amplitudes of protein motions would be inhibited by a more close-packed environment as they are reduced, due to thermal contraction, in the cold membranes.     

Microbiological Evaluation of Protected Environments During Patient Occupancy

Microbiological monitoring has been conducted in two life island (LI) units and two laminar airflow (LAF) rooms while they were occupied by patients undergoing cancer chemotherapy. There were only 5 organisms per 1,000 ft(3) of air sampled in LAF rooms, 31 organisms in LI units, and over 3,000 organisms in regular hospital rooms. None of the floor samples obtained from hospital rooms was sterile, compared to over 70% in LAF rooms. The rate of deposition of organisms onto settling plates was one organism per 4.5 hr in LAF rooms compared to one organism per 0.08 hr in hospital rooms. Potential pathogens were isolated much more frequently from environmental samples obtained from hospital rooms than from LI units or LAF rooms. Two sites of persistent contamination arose in the LAF rooms: the vinyl tile flooring and the water supply system. Over half of the potential pathogens cultured from the protected environment units were cultured initially from the patients who occupied the units.     

Behavior, appetite, and urinary cortisol responses by adult female pigtailed macaques to cage size, cage level, room change, and ketamine sedation

Pigtailed macaques (Macaca nemestrina) and longtailed macaques (M. fascicularis) show behavioral, ecological, and possible temperament differences, and their responses to the laboratory environment might therefore be quite different. We tested pigtailed macaques under the same conditions that were investigated in a previous study with longtailed macaques, using the same comprehensive set of physiological and behavioral measures of stress. First, eight adult females' adaptation to a new room in regulation-size cages was monitored, and in the third week their responses to ketamine sedation were measured. Then they spent two weeks singly housed in each of four cage sizes (USDA regulation size, one size larger, one size smaller, and a very small cage). Half of the subjects were in upper-level cages and the remainder in lower-level cages for the entire study. Cage size, ranging from 20% to 148% of USDA regulation floor area, was not significantly related to abnormal behavior, self-grooming, manipulating the environment, eating/drinking, activity cycle, cortisol excretion, or biscuit consumption. Locomotion and frequency of behavior change were significantly reduced in the smallest cage, but did not differ in cage sizes ranging from 77% to 148% of regulation size. The only manipulation to produce an unequivocal stress response, as measured by cortisol elevation and appetite suppression, was ketamine sedation. Room change and cage changes were associated with minimal cortisol elevation and appetite suppression. Wild-born females showed more appetite suppression after room change than captive-born females. No differences were related to cage level. Pigtailed macaques strongly resembled longtailed macaques except they showed weaker responses to the new room and cage change, probably because the pigtails had spent more time in captivity. These findings support the conclusion that increasing cage size to the next regulation size category would not have measurable positive effects on the psychological well-being of two species of laboratory macaques.