Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microclimate”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1986

Genetic variation of neonatal stress response to reduced temperature brooding in a randombred population of chickens.

Chicks from a randombred population were assessed for genetic variation in 1-day body weight and serum corticosterone under two brooding temperatures (26.7 and 32.2 C). Brooding at 26.7 C resulted in lower 1-day body weights and higher corticosterone levels. Heritability estimates (h2) for 1-day body weight were moderately high in both temperature groups but were low for gain in both temperatures. The h2 for corticosterone level from chicks brooded at 26.7 C was moderate, whereas estimates for those brooded at 32.2 were very low. Statistically significant (but low) negative phenotypic correlations were obtained for corticosterone with body weight and gain in both temperature groups. A significant negative genotypic correlation was observed between corticosterone and body weight for chicks brooded at 26.7 C but not for those brooded at 32.2 C. Corticosterone data from the highest and lowest responding sire families revealed a significant response group by temperature interaction. Chicks from the first of two additional hatches showed significant response group differences in serum corticosterone to the reduced brooding temperature. The neonatal serum corticosterone response to cold stress has a genetic basis; however, because there was a negative genotypic correlation between serum corticosterone and body weight, selection for increased corticosterone levels under reduced temperature brooding would likely result in decreased body size.

Animals↗
PubMed1986

Restricted feeding and reproductive performance of individually caged broiler breeder males.

Two experiments were conducted, one in the summer and another in the fall, involving 95 Hubbard broiler breeder males per experiment. Breeder males were randomly placed in individual cages at 26 (Trial 2) or 30 (Trial 1) weeks of age and provided with five levels of feed intake. The Hubbard White Mountain male Management Guide recommendation (154 g/bird/day) was designated as the control level (100%). Other levels were 115, 85, 70, and 55% of the control level. The effects of feed intake on body weight, semen volume, percent semen-packed cell volume, luteinizing hormone (LH), and testes weight were determined. Body weights were significantly decreased as feed intake was decreased. Dietary restriction levels of 115, 100, 85, and 70% had no significant effects on semen volume or semen-packed cell volume. Dietary restriction of 55% resulted in reduced semen volume, semen-packed cell volume (except in Trial 1), and testes weight. Dietary restriction had no significant effect on LH. A calculated metabolizable energy (ME) value of 346 kcal of ME/bird/day, which lies between the 85 and 70%-fed groups, should be adequate for normal body weight maintenance with the Hubbard broiler breeder male grown in individual cages.

Animals↗
PubMed1986

Corticosteroids and other indicators of hens' well-being in four laying-house environments.

Four presumed criteria of well-being were compared using data from hens of four genetic stocks kept in each of four laying-house environments. Differences between strains selected for increased egg mass and unselected control stocks were not detected, and interactions of selection method with housing environment and periods after housing were not found. Plasma corticosteroid concentrations present during the first 2 weeks after housing were higher than those obtained later. Hens kept in 12-hen, low-density floor pens and 6-hen, high-density cages at 2900 and 310 cm2/hen, respectively, did not differ from each other in corticosteroid levels. However, hens in the floor pens and high-density cages had higher levels than did hens in single-hen, low-density cages and those in 4-hen, moderate-density cages (the latter with floor spaces of 929 and 464 cm2/hen, respectively). Mortality was higher and egg mass per hen housed was less in the 6-hen cages than in floor pens, single-hen cages, and 4-hen cages during the 40-week period following housing. Feather damage and loss increased stepwise and significantly with number of hens per cage. Plasma corticosteroid concentrations did not yield results consistent with other criteria of hens' well-being. There is a need to look beyond the results of corticosteroid assays in establishing hens' well-being in widely different environments.

Adrenal Cortex Hormones↗
PubMed1996

Acute high environmental temperature and calcium-estrogen relationship in the hen.

Much is known about the effects of high environmental temperature (HT) on egg production, but very little is understood about the mechanisms that underlie them. Two experiments were conducted to examine the effects of acute heat stress on circulating estradiol, on calcium uptake by gut tissue, on bone resorption, and on the dynamic relationship between estradiol and calcium in the hen during one ovulatory cycle. In one study, hens were moved individually and randomly into a hot [HT: temperature (T) = 35 C, relative humidity (RH) = 50%; n = 18] or a control, thermoneutral (TN: T = 23 C, RH = 50%; n = 18) environment immediately after a mid-sequence oviposition and brachial vein cannulation. Blood samples (2 mL) were collected every 3 h for 21 h for ionized calcium (Ca2+) and pH determinations and from which aliquots were frozen for 17 beta-estradiol (E2), total calcium (TCa), and inorganic P analysis. Excreta and urine were assayed for TCa and hydroxyproline (OHPr), respectively. A second study was conducted to determine the effects of HT (T = 35, H = 50%, 12 h) vs TN (T = 23 C, RH = 50%, 12 h) on the ability of duodenal cells to take up calcium (CaT). Blood pH and calcium responded to HT as expected (pH increased, Ca2+ decreased, and TCa decreased) and the cyclic pattern of Ca2+ in blood was abolished. The ratio of Ca2+:TCa decreased sharply at approximately the onset of shell calcification in control hens, but in HT hens there was no clear change in the ratio of any point in the cycle. The pattern of E2 typical of hens under normal conditions was significantly depressed in plasma of HT hens. Calcium uptake by duodenal epithelial cells of HT hens was lower than in TN hens. There was a clear inverse correlation between blood Ca2+ and urine OHPr in TN hens (r2 = -73, P = 0.0021) but not in HT hens (r2 = -27, P = 0.32). In addition to alterations in acid-base balance and the status of Ca2+, diminished ability of duodenal cells to transport calcium may be a critical factor in the detrimental effects of heat stress on egg production (numbers), eggshell characteristics, and skeletal integrity often documented in the laying hen.

Animal Husbandry↗
PubMed1989

Influence of personal characteristics, job-related factors and psychosocial factors on the sick building syndrome. Danish Indoor Climate Study Group.

The influence of personal characteristics, life-style, job-related factors, and psychosocial work factors on symptoms of the sick building syndrome was investigated in Greater Copenhagen, Denmark. The buildings were not characterized beforehand as "sick" or "healthy." Of the 4369 employees sent a questionnaire, 3507 returned them. Multivariate logistic regression analyses of the multifactorial effects on the prevalence of work-related mucosal irritation and work-related general symptoms among the office workers showed that sex, job category, work functions (handling of carbonless paper, photocopying, work at video display terminals), psychosocial factors of work (dissatisfaction with superiors or colleagues and quantity of work inhibiting job satisfaction) were associated with work-related mucosal irritation and work-related general symptoms, but these factors could not account for the differences between the buildings as to the prevalence of the symptoms. The building factor (i.e., the indoor climate) was strongly associated with the prevalence of the symptoms.

Adult↗
PubMed1988

Indoor radon exposure and active and passive smoking in relation to the occurrence of lung cancer.

Exposure to indoor radon and radon daughters is currently attracting great interest as a possible cause of lung cancer. This concern is supported by several studies, most of them relatively small in numbers or weak in the assessment of exposure. This study encompasses 177 persons with lung cancer and 677 noncancer referents, all deceased and with 30 years or more of residency in the same house in an area with radon-leaking alum shale deposits in the central part of southern Sweden. Exposure categories based on building material, type of house, and ground conditions were created, but measurements of the indoor radon daughter concentration were also made for 142 cases and 264 referents. Active and passive smoking was ascertained through questionnaires sent to the next-of-kin. Overall, the lung cancer risk was approximately twofold with regard to the categories of assumed radon daughter exposure for the rural sector of the population but not for the same categories of the urban sector, possibly because of less precise exposure assessment and influence from other factors. Occasional and passive smokers, as well as passive smokers alone, had a particularly increased risk of lung cancer in association with the increased exposure categories.

Adult↗
PubMed1985

Work with video display terminals among office employees. II. Physical exposure factors.

This is the second report in a major epidemiologic health investigation on work with a video display terminal (VDT). The first study showed that VDT operators reported more eye discomfort than a reference group not employed in VDT work and that women reported more eye discomfort, musculoskeletal complaints, headache, and skin disorders than men, regardless of whether they worked with a VDT or not. The present report contains the results of the occupational hygiene measurements (indoor climate, lighting and electrostatic conditions). Considerable differences were found between VDT operators and referents and also between sexes. Indications were obtained of a possible relationship between eye discomfort and luminance ratios in the working field of vision. Otherwise, no association could be established between occupational exposure factors and subjective eye discomfort, musculoskeletal complaints, headache, or skin disorders.

Adult↗
PubMedDate not supplied

Forensic entomology.

Forensic entomology is the application of insect biology to the investigation of crime. The subject covers all aspects of insect evidence, but for the purpose of this article the discussion will be restricted to insect evidence from the bodies of persons thought to have been the victims of murder or other unlawful killing.

Adolescent↗
PubMed1997

[An investigation of precipitation of airborne fungi particles in the rooms of university library].

Precipitation of airborne fungi particles in the rooms of an University library and the influencing factors were studied in May 1994 with the fallen plate method. The total average precipitation of airborne fungi particles was 11.68 per dish in 5 minutes. The differences were significant from different room patterns, floors and times, so were the humidity assayed. The book-store rooms and reading rooms had an average precipitation of 15.01 and 8.35 per dish in 5 minutes respectively (P < 0.05), and humidity of 41.7 and 11.4 percent respectively (P < 0.01). The influencing factors were: different floors and room patterns, the people's activity, the different time, humidity, ventilation and book pollution.

Air Microbiology↗
PubMedDate not supplied

[The complex influence of school environmental factors on the health of children].

The combined influence of school environmental factors and a teaching process on children's health was studied in Orenburg. The study demonstrates there is a relationship between some physiological parameters in schoolchildren and the above factors and the level of educational burden. Measures to correct poor school factors are required.

Cardiovascular Physiological Phenomena↗