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At least 1,621 records · Page 90Linked to original sources
PubMed1996

Energy expenditure variations in soldiers performing military activities under cold and hot climate conditions.

This study assessed the energetic status of soldiers exposed to intense physical activities in cold and warm weather. Thirty subjects participated in a two-phase study group A (n = 18) in the winter phase and group B (n = 12) in the summer phase. Energy expenditure (EE) was measured by the doubly labeled water technique; after a single, oral dosing of 2H(2)18O, daily urine samples were collected for 12 successive days. Energy intake (EI) was assessed from detailed food records analyzed by computerized food charts. Energy balance was calculated as the difference between EI and EE for each subject. Mean (+/- SE) daily EE was 4,281 +/- 170 and 3,937 +/- 159 kcal/day for the winter and summer groups, respectively. Daily EI was 2,792 +/- 124 kcal/day in group A and almost identical in group B. A negative energy balance of 1,422 +/- 163 kcal/day and 924 +/- 232 kcal/day (not significant) was calculated for groups A and B, respectively. Energy expenditure is primarily determined by the level of activity rather than by climate conditions; EI is insufficient to offset the high energy requirements under these conditions.

Adult↗
PubMed1977

Climatic droplet keratopathy in a 16-year-old boy.

Primary climatic droplet degeneration of the cornea that consisted of bandshaped keratopathy and superficial spheroidal golden opacities occurred in a 16-year-old boy. Light microscopy showed proteinaceous deposits in the superficial corneal stroma. Electron microscopy confirmed the colloidal nature of this material.

Adolescent↗
PubMed1996

Humidification of oxygen with unheated humidifiers in tropical climates.

In developing countries, oxygen therapy in hospitals is frequently humidified with unheated bubble-through humidifiers. We assessed the efficacy of humidification under such circumstances. The water temperature in the humidifier and the ambient air temperature were measured and compared to the oxygen flow rate. It was calculated that oxygen was cooled in the humidifier by 6.12 degrees C (95% CI: 5.88; 6.35) per liter of flow for flow rates up to 2 l/min. Using the average temperatures on the hospital ward in January and August, and the WHO-recommended flow rates of 0.5 l/min and 1 l/min, the relative humidity of the oxygen delivered to a child was estimated to be between 34% and 56%. We conclude that unheated bubble-through humidifiers achieve low humidity in oxygen in tropical climates. Some of the complications associated with the use of nasopharyngeal catheters for the delivery of oxygen might be explained by this, as oxygen of low humidity and temperature is delivered directly into the posterior nasopharynx.

Acute Disease↗
PubMed1985

Associations between dermatoglyphic variation, topography, and climate in Kenya.

Correlations between a number of dermatoglyphic finger and palmar taxonomic traits relating to 57 male and 53 female Kenyan populations, and altitude and mean annual rainfall are significant, not only in terms of the full range of samples, but also when samples are divided into independent smaller groups. These results are discussed and contrasted with those of other studies which have found no relationships between dermatoglyphic variation and climate in sub-Saharan Africa.

Altitude↗
PubMed2005

Geographical distribution of hot flash frequencies: considering climatic influences.

Laboratory studies suggest that hot flashes are triggered by small elevations in core body temperature acting within a reduced thermoneutral zone, i.e., the temperature range in which a woman neither shivers nor sweats. In the present study, it was hypothesized that women in different populations develop climate-specific thermoneutral zones, and ultimately, population-specific frequencies of hot flashes at menopause. Correlations were predicted between hot flash frequencies and latitude, elevation, and annual temperatures. Data on hot flash frequencies were drawn from 54 studies. Pearson correlation analyses and simple linear regressions were applied, first using all studies, and second using a subset of studies that included participants only to age 60 (n = 36). Regressions were repeated with all studies, controlling for method of hot flash assessment. When analyses were restricted to studies that included women up to age 60, average temperature of the coldest month was a significant predictor of hot flash frequency (P < 0.01), explaining 29.2% of the variation in hot flash frequency. In a separate equation, the difference between hottest and coldest temperatures was also a significant predictor (P < 0.01), explaining 26.4% of the variation in hot flash frequency. When regressions used all studies but controlled for method of hot flash assessment, average temperature of the coldest month, difference between hottest and coldest temperatures, and mean annual temperature were significant predictors of hot flash frequency. Women reported fewer hot flashes in warmer temperatures, and more hot flashes with increasing seasonality. These results suggest that acclimatization to coldest temperatures or sensitivity to seasonality may explain part of the population variation in hot flash frequency.

Body Temperature Regulation↗
PubMed2002

Pattern of birth and eating attitudes in young adults: failure to replicate in a warmer climate.

OBJECTIVE: Previous research (based in the United Kingdom) has shown a link between warmer temperatures at birth and restrictive eating attitudes in early adulthood. The current study examined whether this pattern can be replicated in a warmer area of the northern hemisphere (Southwest Spain). METHODS: The participants were 261 preuniversity volunteers (125 women and 136 men) born in Extremadura, Southwest Spain. Mann-Whitney tests and chi-square analyses were used to compare the eating characteristics of participants born in warm versus cooler months. Spearman's rho was used to test for dimensional associations between temperature at birth and eating characteristics. RESULTS: There were no links between temperature at birth and restrictive eating attitudes, whether temperature and eating pathology were considered dimensionally or categorically. DISCUSSION: The association of temperature at birth and restrictive eating pathology in early adulthood is not replicable in a warmer climate. Possible explanations are suggested to account for this pattern of findings.

Adolescent↗
PubMed2005

Thermoregulatory adaptations of the overwintering captive raccoon dog (Nyctereutes procyonoides) in boreal climate.

The raccoon dog (Nyctereutes procyonoides) is a nocturnal canid thought to utilise passive wintering strategy in the boreal climate. To record the deep body temperature (T(b)), 12 farmed raccoon dogs were implanted with intra-abdominal T(b) loggers on November 26, 2003. Between December 3, 2003 and January 27, 2004 half of the animals were fasted for 8 weeks. The amplitude of the diurnal T(b) oscillations increased due to fasting. However, the mean diurnal T(b) was lower in the fasted animals only during two occasions. Unlike observed previously in other species, not only did the raccoon dogs experience hypothermia between 0600 and 1000 hr but also hyperthermia between noon and 1800 hr. The fasted animals were as active as the fed animals measured after 42-43 days of fasting and there was a significant cross-correlation between physical activity and T(b). The nocturnal period of hypothermia is probably an adaptation to save energy during food deprivation. The diurnal hyperthermia could be explained by the opportunistic foraging behaviour of the species. Opposite to the established assumptions, the raccoon dog does not seem to enter winter sleep on fur farms. In the future it is important to determine if true winter sleep occurs in nature in the species.

Adaptation, Physiological↗
PubMed2002

Environmental fate of metalaxyl and chlorothalonil applied to a bentgrass putting green under southern California climatic conditions.

Putting greens usually receive high inputs of fertilizers and pesticides to meet the high demand for visual quality and to overcome the stress from close mowing and traffic. In this study, two commonly used fungicides, metalaxyl (methyl N-(methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate) and chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), were evaluated for their partitioning and persistence in a bentgrass (Agrostis palustris Huds) putting green under southern California climatic conditions. The putting green site was constructed according to the US Golf Association (USGA) specifications. Lysimeter assemblies installed at the center of each plot were used to monitor the leachate, flux chambers were used to measure volatilization, clippings were collected to determine the residues on grass, and soil cores were sampled to determine residues in the soil profile. Results showed that cumulative volatilization loss accounted for 0.10 and 0.02%, clipping removal 0.11 and 0.13%, and cumulative leaching 0.71 and 0.002% of the applied metalaxyl and chlorothalonil, respectively. The two fungicides were mainly found in the top 10 cm of the soil profile due to the high organic carbon content in the thatch and mat layers. The dissipation half-life was 1.4 days for metalaxyl and 4.9 days for chlorothalonil on grass, shorter than those found in agricultural fields. This study showed that, under normal turf management practices, the offsite transport of the parent fungicides was minimal. Future research should focus on investigating the fate and mobility of the metabolites of the fungicides.

Adsorption↗
PubMed2004

Climate change and decreasing herbicide persistence.

A herbicide degradation model, using real weather data for the period 1980-2001, has been used to estimate the change in persistence of autumn-applied isoproturon over this period. The results suggest that soil residues fell to the minimum for weed control on average approximately 30 days earlier over the last 5 years of this period than in the first 5 years, equivalent to a reduction of approximately 25% in the duration of weed control. This decline in persistence is attributed to increasing soil temperature. The results are discussed in relation to recent observations and predictions on climate change. The relevance of the findings to other pesticides and future weed control is considered.

Climate↗
PubMed2000

Influence of carbon dioxide clouds on early martian climate.

Recent studies have shown that clouds made of carbon dioxide ice may have warmed the surface of early Mars by reflecting not only incoming solar radiation but upwelling IR radiation as well. However, these studies have not treated scattering self-consistently in the thermal IR. Our own calculations, which treat IR scattering properly, confirm these earlier calculations but show that CO2 clouds can also cool the surface, especially if they are low and optically thick. Estimating the actual effect of CO2 clouds on early martian climate will require three-dimensional models in which cloud location, height, and optical depth, as well as surface temperature and pressure, are determined self-consistently. Our calculations further confirm that CO2 clouds should extend the outer boundary of the habitable zone around a star but that there is still a finite limit beyond which above-freezing surface temperatures cannot be maintained by a CO2-H2O atmosphere. For our own Solar System, the absolute outer edge of the habitable zone is at approximately 2.4 AU.

Atmosphere↗
PubMed1998

Modelling the distribution and abundance of Culicoides imicola in Morocco and Iberia using climatic data and satellite imagery.

Relative abundances of Culicoides imicola at 22 sites in Morocco were compared with climatic variables, altitude and the NDVI (Normalised Difference Vegetation Index, a satellite derived measure of photosynthetic activity) of the same sites. Abundances were negatively correlated with wind speed and positively correlated with the average and minimum NDVI (NDVImin). There were no significant correlations with air or soil temperatures, relative humidity, saturation deficit, rainfall, altitude or mean annual maximum or range of NDVI. The best 2-variable model, which combined wind speed and NDVImin as predictors, explained over 50% of the variance in abundance. It is suggested that wind speed affects the abundance of C. imicola by causing adult mortality while NDVImin provides a measure of the availability of C. imicola breeding sites. Data from 27 sites in Iberia yielded broadly similar results to those found in Morocco although the great abundance of C. imicola at Milfontes (Portugal) could not be accounted for. Several northern sites where the NDVImin is sufficiently high to suggest the presence of C. imicola but where it appears to be absent indicate that there may be a northern limit to the distribution of C. imicola in Iberia that is independent of NDVImin. The potential use of NDVImin to predict the distribution of outbreaks of African horse sickness was investigated using data from the 1989-1990 epizootic in northern Morocco. Within the cluster of outbreaks in Larache province is a corridor of very low NDVImin in which few or no outbreaks were reported.

African Horse Sickness↗
PubMed1989

Traveller's diarrhea among Austrian tourists in warm climate countries: I. Epidemiology.

Travellers from temperate climates to the tropics of the Third World face a high risk of acquiring traveller's diarrhea. Epidemiology plays a major role in the exact description of this syndrome. This paper describes the epidemiology of traveller's diarrhea in 3696 Austrian tourists and the influence of various epidemiologic parameters on incidence is evaluated. Destination and season of travel influences attack rates, in particular in the sub-tropics. High (up to app. 60% incidence) and low risk (below 35% incidence) regions can be described, exhibiting risk differences of nearly 100%. Individual parameters, like age and body weight, can influence the risk in an evident manner and, or course, the duration of stay plays a major role. It is pointed out that accommodation and travel characteristics are important factors for risk evaluation, as well as dietary hygiene.

Adult↗
PubMed1978

The geographical distribution of multiple sclerosis, rheumatoid arthritis, rheumatic heart disease and poststreptococcal nephritis in Sardinia: climatic and socioeconomic factors.

The comparative geography of multiple sclerosis (MS) and nonneurological diseases considered to be autoimmune is of great interest. But there are few appropriate investigations. Some have found an increase in the frequency of MS, rheumatoid arthritis and rheumatic heart disease depending on the geographic latitude. Nevertheless, the significance of the latitude effect as an indicator of a possible etiological relationship between MS and these conditions has been questioned. In this paper, the frequency of MS, rheumatoid arthritis, rheumatic heart disease and poststreptococcal nephritis is reported from Sardinia where appreciable differences in climatic and socioeconomic conditions exist. There was a positive correlation of the distribution of MS with the distribution of rheumatic heart disease and poststreptococcal nephritis. On the other hand, no correlation was found with the distribution of rheumatoid arthritis.

Adolescent↗
PubMed1996

Climatic factors associated with the infection of herds of cattle with bluetongue viruses.

The incidence of bluetongue virus infection of 15 cattle herds in Queensland, Australia, was determined by a serum neutralization test. The maximum temperature (degree C), minimum temperature (degree C) and rainfall (mm) data were obtained from the meteorological recording stations closest to each herd. Using unweighted least-squares regression analysis, the best statistical model explaining the most variability in the herd incidence rate included the ratio between the maximum and minimum temperature recorded at both 1 month and 6 months preceding seroconversion, and rainfall recorded at both 2 months and 6 months preceding seroconversion. More than 90% of the variability in the incidence of bluetongue virus infection in the herds was explained by the model, a considerable improvement on previous models that used prevalence data. The prospective nature of the study also supports a strong causal relationship between climatic factors and the occurrence of infection in cattle herds.

Analysis of Variance↗
PubMed1989

Climate and physiological heat strain during exercise.

A body-atmosphere energy exchange model (BIODEX) using heat transfer theory and empirical relationships is described which predicts the change in body core temperature during exercise as an index of thermal strain. Index values may be interpreted as the length of the period of activity before the heat load on the body causes internal body temperature to rise to critical levels. The performance of the model tested under controlled laboratory conditions using human subjects was found to be reliable. BIODEX is used to show the thermal significance of midsummer climatic conditions in New Zealand for those jogging outdoors.

Climate↗
PubMed1983

Mineral status of grazing beef cattle in the warm climate region of Florida.

An experiment was conducted to determine the mineral status of purebred Brahman beef cattle grazing Bermuda--Bahia pastures grown on sandy, well-drained soils in Central Florida. Soil, plant, blood serum and liver tissue concentrations of calcium, potassium, sodium, magnesium, manganese and cobalt were generally adequate. Sixty-nine per cent of forages and 40% of serum samples were deficient in phosphorus. Seventy-five per cent of soils, 38% of forages and 18% of liver samples were deficient in copper. Sixty-nine per cent of forage samples were low, less than 30 ppm, in iron. All samples of forage, liver and serum were deficient in selenium. Likewise, all soil and forage samples and 47 and 88% of serum and liver samples, respectively, were deficient in zinc. Mineral elements most likely deficient and needed in supplements for grazing cattle on sandy, well-drained soils in the warm climate region of Central Florida are phosphorus, copper, selenium and zinc.

Animals↗
PubMed1989

Mean skin temperature in warm humid climates.

Mean skin temperature (Tsk) was measured in 24 subjects during experiments in a climatic chamber. Three conditions of ambient temperature (Ta = 25.6 degrees, 28.9 degrees and 32.2 degrees C), and three of humidity (relative humidity = 50%, 70% and 90%) were studied. A relationship was established by a linear regression technique. It is valid in the 24 degree-34 degree C range, for air velocity = 0.2 m.s-1, clothing insulation = 0.077 degrees C.m2.w-1 (0.5 clo), metabolic rate = 64 w.m-2 (1.1 met) and radiant temperature = air temperature. In these conditions Tsk = 28.125 + 0.021 Pw + 0.210 Ta (Pw: ambient water vapour pressure in mb). It shows a small humidity influence. The influences of sex, transition from one condition to the next, and air velocity were also studied. Measurements in Africa confirmed the small influence of humidity. Ethnic life-style differences indicated that a high precision in Tsk determination is difficult to achieve.

Adult↗
PubMed2005

Determinants of vitamin D status in older women living in a subtropical climate.

Studies performed in the Northern Hemisphere and in areas distant from the equator have demonstrated significant seasonal variation in 25-hydroxyvitamin D (25OHD) levels. Whether such variation occurs in a subtropical area such as Australasia is not clear. We performed a cross-sectional study of 1,606 healthy, postmenopausal women recruited over a 33-month period. The study had three goals: to determine the normal levels of 25OHD in healthy postmenopausal women living in Auckland, New Zealand; to determine whether seasonal variation of 25OHD occurs at this latitude; to assess the relationship between 25OHD, biochemical indices, anthropometric variables and bone mineral density (BMD). We found significant seasonal variation in 25OHD levels, with the change in monthly ultraviolet dose from summer to winter being followed 6-8 weeks later by a corresponding change in 25OHD levels. Vitamin D insufficiency (25OHD <50 nmol/l) was common. During summer, 28-58% of participants had suboptimal vitamin D status, while in winter, the frequency increased to 56-74%. 25OHD levels correlated with participants' age (r=-0.15), weight (r=-0.11), body mass index (r=-0.13), fat mass (r=-0.14), percentage body fat (r=-0.16), physical activity (r=0.10) and the month of blood sampling (all P<0.0001). Collectively, age, fat mass, physical activity, and month of sampling explained 21% of the variance in 25OHD. No significant relationships were noted between 25OHD and BMD at any site. Other variables that showed significant monthly variation were glucose (P=0.002), serum phosphate, alkaline phosphatase, and albumin (all P<0.0001). There was no monthly variation in BMD at the lumbar spine or proximal femur. In conclusion, there is significant seasonal variation in 25OHD levels, even in a subtropical climate. Furthermore, despite generous amounts of sunlight, considerable numbers of women have suboptimal vitamin D status, even in summer. Our findings support the suggestion that vitamin D supplementation should become standard practice in this population of women, particularly during winter.

Adipose Tissue↗