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[Effect of microclimate on the development of parasitic arthropods].

The paper contains a survey of methods used and experience gained during the 25-year research of the influence of microclimate on the existence and development of parasitic arthropods at the Institute of Parasitology, Czechoslovak Academy of Sciences. Research methods by means of apparatuses, organization of long-term experiments and procedures in the assessment of results are described. An emphasis is put on the inter-disciplinary character of such working trend and on the advantage of creating complex working teams, in which the biologist must be the initiator and coordinator of the studies.

Academies and Institutes↗
PubMed1985

[Microclimate parameters in an isolation nursery for calves].

An experiment was carried out to establish the dynamic of some microclimate parameters on a transformed premise for the raising of calves up to 15 days of age. The newborns were accommodated in group boxes (2 to 5 animals) located in two rows, with a central path between them. The illumination coefficient was 1:14, and air exchange was effected through natural ventilation. The feeding of the newborn calves on the first and second day took place four times with colostrum and milk taken from their own dams and from the third day on it was performed three times a day. From the fourth day pooled milk was used, and from the seventh day the calves were offered concentrated fodder, hay, and water. The temperature and humidity regime of the air was investigated via thermohygrograph TZ18, and air velocity was checked periodically by means of Hill's catathermometer; the amount of carbon dioxide was measured after Wolpert, and that of ammonia gas--colorimetrically through indicator tubes. It was found that in the nursery under investigation no optimal temperature and humidity regime of the air was provided in the winter and transitive seasons. In winter there were highest percent of gastrointestinal and respiratory diseases. The air cooling coefficient was higher than the optimal one in the winter season, and it was lower in summer. Air velocity and gas admixture values proved within the admissible hygiene range.

Air Movements↗
PubMed1983

[Effect of microclimate, supplementary mineral elements Cu, Mn and Zn and vitamins A + D3 on selected blood indicators and piglet rearing].

The studied were carried out in the production conditions of the State Farm Machnów, involving 502 piglets of the Polish large-whitebreed at the age from the birth to 42nd day of life in two rearing cycles (winter-spring and spring-summer). The author studied the effects of piglet rearing and the behaviour of hematological and biochemical indices of blood in conditions of optimal microclimate without additional amounts of iron, vitamin A + D3 (30,000 m. u. of vitamin A and 10,000 m. u. of vitamin D3) in the 3rd and 10th day, and with a mineral mixture containing 0.008 of copper sulphate, 0.03 g of zinc sulphate, 0.03 g of manganese sulphate given per head daily from the 10 to 20th day of life. The most favourite rearing effects were obtained in the experimental group with the mineral mixture (0.82% of losses), and the highest lethality was found in the group without iron added (13.73%). The highest values of hematological indices (hematocrit, hemoglobin and erythrocytes) were recorded in the group receiving the mineral mixture and vitamins A + D3.

Animal Husbandry↗
PubMed1978

Microclimate as a determining element in the distribution of ticks and their development cycles.

The paper deals with the problem of interrelationship between macroclimate of the region, mesoclimate of the biotope studied and microclimate of the tick niches proper, necessary for the research of tick ecology. New methods for the solution of microclimatological studies are proposed and the relationship between macro-and mesoclimate, or that between temperature in the tick cage and environment, is formulated. In choosing optimal intervals of data acquisition a two-hour interval (every even hour of the day) has proved to be the most suitable.

Animals↗
PubMed1978

[Microclimate and the mortality among turkey poult broilers].

Zoohygiene studies have been carried out in the course of two years, following up periodically at 20--25-day intervals the concentration of ammonia gas and hydrogen sulfide, the relative humidity, and the temperature within the houses of an industrial animal-breeding complex for the production of broiler turkey-poults. Parallel investigations have aimed at following up the morbidity and mortality rates among the birds. Part of them divided into age groups, have likewise been studied in terms of total protein and protein fractions of the blood serum along with the establishing of the blood bactericidal titer. Dependable values have been found of the interrelationship between the age of the turkey-poults and their mortality rate. The same have proved to be the values expressing the correlation between the air concentration of ammonia gas in the farm houses and the mortality rate shown. It is concluded that the mortality rates established in the turkey combine might probably be due to the action of comlex factors, mainly to inappropriate microclimate and incomplete raising technology that contribute to the appearance and development of pathogenic and occasionally pathogenic agents as well as of some noninfectious diseases.

Air Pollutants↗
PubMed1994

[Development of peripheral neurovascular disorders in miners exposed to cool microclimate].

Complete clinical and physiologic examination of 415 tunnelers exposed to intensive vibration in cooling microclimate proved that extreme functioning of thermoregulation results in shorter development, quicker progression of vibration disease and abortive types of the disease. The data obtained were helpful to base treatments and prophylaxis including special clothes, appropriate therapy.

Adaptation, Physiological↗
PubMed1994

[Age-related functional characteristics of miners exposed to heat microclimate].

The article describes the functional changes with age in miners of deep coal mines in heating microclimate. The individuals of medium and senior age groups appeared to have significantly more frequent cardiovascular and thermoregulatory disorders than in the same age groups in normal climate. High temperature impairs autonomic nervous system, which presents hyperactivity of sympathicus and marked vegetative reactions in all ages, especially in the young workers.

Adult↗
PubMed1993

[Effects of microclimate, hardness of work and heat resistance on the allowable duration of human work].

Studies revealed the influence of microclimate and ergogenic parameters on allowable duration of work in humans with different levels of heat resistance. Regression equations are calculated so as to forecast the allowable duration of work in high, medium and low heat resistant humans. The allowable duration of work can be normalized physiologically by means of suggested principle, which is worthy to be applied in various industries.

Adult↗
PubMed1994

[Hygienic aspects of the microclimate in intensive management of rabbits].

In a four-row cowshed adapted for rabbit housing, air temperatures and humidity were recorded ambulantly and instrumentally, air flow rate, cooling variable, gas content in the air, microbial contamination of air and dust deposition were determined ambulantly in the years 1991-1992 and in January to April 1993. The values of ambulant measurings show that at the outside temperature -0.5 degrees C to -5.0 degrees C the microclimate quality decreases particularly with respect to the drop of air temperature in the cowshed below 10.0 degrees C, to the increase in cooling variable up to the value 53.17 mW/cm2 and to the increase in NH3 and CO2 content to 50 ppm and/or 0.45 vol.% in absolute maximum values. In these circumstances, the average determined values of both gases are higher than the standard prescription. At outside temperatures above 27.0 degrees C the average relative air humidity in the cowshed made 69.20% for the average temperature of 25.0 degrees C. To avoid the water vapor tension exceeding the limit in the cowshed air above the value 14.1 mm Hg, when sultry atmosphere sets in, the average relative air humidity should be maximally 59.0%. Hence the cowshed was found to be insufficiently ventilated at high outside temperatures above 27.0 degrees C, and it is recommended to increase the ventilator performance and at the same time to reduce water evaporation from catchpit surfaces when urine output of rabbits is excessive as a result of the increased water intake. Temperature and air humidity readings confirmed the need of heating source installation when the outside temperatures drop below 0.0 degrees C. Evaluation of air microbial contamination showed high counts of molds and particularly of micrococci in comparison with the ambience of a cage facility for piglet raising at a repopulation station with strict hygienic regime. Microbial picture of dust deposition was positively influenced by longitudinal aerosol disinfection of the air in the cowshed.

Air Microbiology↗
PubMed1977

Influence of microclimate on the life cycle of the common tick Ixodes ricinus (L.) in an open area in comparison with forest habitats.

Under conditions of the South-Moravian region of Pannonian climate (Valtice near Breclav), the life cycle of the common tick Ixodes ricinus (L.) was studied and a continous recording of main elements of microclimate (temperature and humidity) was carried out in an open grassy area. Simultaneously the process of hibernation was studied in four soil layers (surface, depths of 10, 20 and 30 cm). Observations were assessed by mathematiccal-statistical tests and compared with the results obtained by the same methods in the forest biotope (tipe of thermophilic oak forest)and in the ecotone of forest margin (Daniel et al. 1976). The ticks are able to complete the developmental cycle also in the open grassy areas, where during the vegetation period the development proceeds more quickly than in the forest but with considerably higher losses. In the discussion the conclusions are compared with literary data from other parts of Czechoslovakia.

Animals↗
PubMed1996

[Regulation of microclimate at workplaces of industrial accommodations].

The article describes methodic approaches to regulation of optimal and allowable microclimate in industrial compartments. Those approaches include concepts that justify criteria of human heat state during variable physical activities, industrial testing of experimental data, evaluation of health state according to transitory disablement records and medical or epidemiologic studies. Having considered relationships between workers heat state and the environmental temperature load, the authors presented an equation to determine upper allowable limit of the latter.

Adult↗
PubMed1981

Intestinal folic acid absorption and the acid microclimate. The effects of compounds relevant to folate malabsorption.

The effect s of various substances and circumstances on folic acid absorption and surface pH were investigated in vitro in rat proximal jejunum. Prior consumption of alcohol and libitum, phenytoin and in vitro methotrexate had no effect on folate absorption. In contrast, ethanol in vitro, low sodium ion containing buffers in vitro and oral methotrexate given prior to experiment reduced absorption. Folate absorption did not correlate with water movement since methotrexate decreased folate but enhanced fluid absorption, ruling out direct coupling. Surface pH was elevated by the low sodium ion containing buffers, ethanol in vitro and oral methotrexate, correlating inversely with folate absorption. The parallelisms between absorption and changes in surface pH support the microclimate hypothesis of folic acid absorption where the rate of transport is largely determined by the surface pH of the proximal jejunum.

Animals↗
PubMed2005

The importance of microclimate variation in determining size, growth and survival of avian offspring: experimental evidence from a cavity nesting passerine.

Organisms are expected to balance energy allocation in such a way that fitness is maximized. While much research has focussed on allocation strategies of reproducing parents, in particular birds, relatively little attention has been paid to how nestlings allocate energy while in the nest. Nestling birds are faced with a trade-off between devoting energy to growth or to thermoregulation, and in altricial species it is likely that the thermal environment of the nest site influences the nature of this trade-off. Here, we experimentally investigate how altering the microclimate of nests affects the growth, size and survival, as well as cell-mediated immune (CMI) response, of nestling tree swallows (Tachycineta bicolor) in a temperate environment. We place air-activated heating pads in nests of swallows when young were between 4 days and 16 days of age, and compared performance of offspring to control nests. Our manipulation raised temperatures of heated nests by approximately 5 degrees C compared to control nests. Offspring in heated nests had enhanced survival while in the nest, and we also found that they were heavier and had longer ninth primary feathers at 16 days of age. In addition, heating nest boxes resulted in significantly faster growth of primaries, and there was a trend for growth rates of mass to also be higher in heated nests. There were no significant differences between heated and control nests in growth rate or size of tarsus at age 16 days, and we speculate that this lack of response to elevated nest temperatures may be due to growth of skeletal structures being limited by other factors such as calcium availability. We also found no difference between heated and control nests in CMI response. Nonetheless, our results show overall that increasing temperatures of nests has significant benefits that enhance the fitness of offspring. As provisioning rates to offspring did not differ between heated and control nests, we suspect that the beneficial effects of heating were not the consequence of changes in parental behaviour. Our results provide insight into factors, other than food supply, that have important consequences in determining reproductive success of birds breeding in temperate environments.

Analysis of Variance↗
PubMed1987

pH of the microclimate lining human gastric and duodenal mucosa in vivo. Studies in control subjects and in duodenal ulcer patients.

Measurements of pH in the microclimate on gastric and duodenal mucosa were made during gastrointestinal endoscopy in 21 normal subjects and 9 duodenal ulcer patients. In controls luminal and juxtamucosal mean pH (+/- SEM) of 3.29 +/- 0.3 and 4.48 +/- 0.25 were recorded respectively in distal esophagus, 2.01 +/- 0.17 and 4.84 +/- 0.37 in gastric fundus, 1.82 +/- 0.12 and 5.5 +/- 0.15 in body, 3.52 +/- 0.34 and 5.42 +/- 0.29 in antrum, 6.89 +/- 0.21 and 7.16 +/- 0.13 in duodenal cap, and 6.84 +/- 0.19 and 7.03 +/- 0.19 in proximal duodenal loop. When the lumen of esophagus and duodenum were perfused with acid (pH 2) luminal and mucosal pH values were 2.18 +/- 0.11 and 4.08 +/- 0.41 in esophagus, 2.57 +/- 0.15 and 6.74 +/- 0.13 in duodenal bulb, and 2.44 +/- 0.14 and 6.39 +/- 0.2 in duodenal loop. Juxtamucosal pH in fundus, body, and duodenum remained near neutral when luminal pH was 1.5, but in distal esophagus and antrum it fell sharply at luminal pH values below 3. In duodenal ulcer patients juxtamucosal pH in the cap was significantly lower than that in normals at luminal pH values below 3. These studies support the hypothesis that a "mucus-bicarbonate" barrier inhibits mucosal acidification in humans and that duodenal mucosa in ulcer patients is less able to maintain a neutral zone adjacent to it in the face of luminal acid.

Adult↗
PubMed1994

Effects of ozone on managed pasture: I. Effects of open-top chambers on microclimate, ozone flux, and plant growth.

Open-top chambers (OTC) were established in a field of managed pasture, and environmental parameters were recorded inside and outside to study the influence of OTCs on radiation, air temperature (T(air)), saturation vapour pressure deficit (svpd), and soil water content in relationship to plant growth and yield. Canopy development in OTCs supplied with non-filtered air (NF) and in ambient (AA) plots was followed by measuring leaf area index (LAI). The dry matter yield was determined after three growth periods in each of two consecutive seasons. Boundary layer conductance (g(bw)) and wind speed (u) were measured along a vertical profile, and day-time flux were measured along a vertical profile, and day-time flux of O(3) was estimated throughout the experiment on the basis of a mass balance. The vertical profile of u showed values in the range 1-1.2 m s(-1) at the top of the canopy, and maximum g(bw) was 20-25 mm s(-1). Average reduction in global radiation in OTCs was 25%, and volumetric soil water content was reduced by about 5%. Daily mean T(air) was increased by 1.3 degrees C, mean daily maximum svpd by 0.08 kPa, and the temperature sum (degree days with base temperature of +5 degrees C) by 12%. Fluctuations in the difference in daily mean T(air) and svpd during the daytime between OTCs and ambient air were related to canopy structure. Differences were largest after each cut and declined with increasing LAI. A small effect of changes in LAI on T(air) and svpd occurred during periods with low soil water content. The flux of O(3) in OTCs was largest (>100 microg m(-2) min(-1)) before and smallest (<20 microg m(-2) min(-1)) after each cut. Calculated deposition velocities for O(3) (nu(d)) in the range 0-3 cm s(-1) were generally higher than those measured under most field conditions. Overall, in OTCs the deficit in soil and atmospheric moisture was larger than in the open field, and the increase in daily mean T(air) was strongly influenced by the stage of canopy development. Changes in microclimate and incoming radiation affected pasture development. LAI was slightly reduced in OTCs as compared to AA plots. The total accumulated dry matter yield for all six growth periods was only about 7% lower in OTCs, but the contribution of clover to total forage mass declined during the experiment. OTCs had no significant effect on weeds. The results indicate that OTCs reduced the competitiveness of clover, and that the increase in growth of grasses compensates for the loss in clover yield. The shift in species composition caused by OTCs must be considered when studying the effect of pollutants on pasture.

Journal Article↗
PubMed2006

Prediction of microclimate pH in poly(lactic-co-glycolic acid) films.

An equilibrium mathematical model that accurately predicts microclimate pH (mupH) in thin biodegradable polymer films of poly(lactic-co-glycolic acid) (PLGA) is described. mupH kinetics was shown to be primarily a function of: (i) kinetics of water-soluble acid content and composition in the polymer matrix and (ii) polymer/water partition coefficient of water-soluble degradation products (P(i)). Polymers were coated on standard pH glass electrodes, and mupH was measured potentiometrically. Water-soluble acid distribution and content in PLGA films were determined by pre-derivatization HPLC. Polymer degradation products partitioned favorably in the polymer phase relative to water (P(i) range: approximately 6-100), and P(i) increased with increasing hydrophobicity of the acidic species according to a linear free energy law related to reversed phase HPLC retention time for the corresponding derivatized bromophenacyl esters. The mupH predicted by the model was in excellent agreement with experimental mupH for several PLGAs as a function of time and PLGA lactic/glycolic acid ratio. These data may be useful to slowly release pH-sensitive PLGA-encapsulated bioactive substances and provide a general framework for predicting partitioning behavior of degradation products in biodegradable polymers.

Chromatography, High Pressure Liquid↗
PubMed2005

The vulvar skin microenvironment: impact of tight-fitting underwear on microclimate, pH and microflora.

The aim of the present study was to investigate if tight-fitting underwear (string panties) equipped with string panty liners affected the vulvar skin microenvironment differently to regular panties with standard panty liners. Thirty-two healthy women participated in a crossover study where temperature, humidity, surface pH and aerobic microflora were measured on vulvar skin. Vulvar skin temperature was 35.2 +/- 0.19 (mean +/- SEM) and 35.3 +/- 0.17 degrees C, respectively, for the two underwear systems. Mean humidity and mean skin surface pH at vulvar skin did not differ between the two systems. Barely noticeable differences were found for the aerobic microflora both at labium majus and at perineum. The mean total number of microorganisms in the two different panty liners was the same, 6.0 +/- 0.15 and 6.0 +/- 0.16, respectively (log CFU per panty liner). The differences in panty and panty liner design studied seem to have negligible impact on the vulvar skin microclimate, skin surface pH and aerobic microflora. No support was found for the assumption that a string panty system would result in higher contamination of vulvar skin by anorectal microflora.

Adult↗