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PubMed2001

Educational strategies used in increasing fluid intake and enhancing hydration status in field hockey players preparing for competition in a hot and humid environment: a case study.

The purpose of the present study was to develop a hydration strategy for use by female English field hockey players at the 1998 Commonwealth Games in Malaysia. An additional aim was to initiate the process of acclimation. Fifteen elite players, mean age (+/-SEM) 24.1 +/- 1.19 years, height 1.67 +/- 0.01 m, and body mass 62.8 +/- 1.76 kg, took part in a 5-day training camp immediately prior to departure for the Games. In order to develop the hydration strategy, training took place under similar environmental conditions to those to be experienced in Malaysia (i.e., 32 degrees C, 80% humidity). Acclimation training consisted of 30-50 min of either continuous, low intensity cycling or high intensity intermittent cycling, which more closely replicated the pattern of activity in field hockey. Body mass measures taken each morning, and pre and post training, together with urine color measures, were used to assess hydration status. Pre-loading with up to 1 L of a 3% carbohydrate-electrolyte solution or water immediately prior to acclimation training, as well as regular drinks throughout, ensured that players avoided significant dehydration, with percent body mass changes ranging from -0.34% to +4.24% post training. Furthermore, the protocol used was sufficient to initiate the process of acclimation as demonstrated by a significant reduction in exercising heart rate and core temperature at all time points by days 4 and 5. In conclusion, although labor intensive and time consuming, the camp was successful in developing a hydration strategy that players were able to utilize once at the Games.

Adult↗

PubMed2003

Mediterranean moisture source for an early-Holocene humid period in the northern Red Sea.

Paleosalinity and terrigenous sediment input changes reconstructed on two sediment cores from the northernmost Red Sea were used to infer hydrological changes at the southern margin of the Mediterranean climate zone during the Holocene. Between approximately 9.25 and 7.25 thousand years ago, about 3 per thousand reduced surface water salinities and enhanced fluvial sediment input suggest substantially higher rainfall and freshwater runoff, which thereafter decreased to modern values. The northern Red Sea humid interval is best explained by enhancement and southward extension of rainfall from Mediterranean sources, possibly involving strengthened early-Holocene Arctic Oscillation patterns and a regional monsoon-type circulation induced by increased land-sea temperature contrasts. We conclude that Afro-Asian monsoonal rains did not cross the subtropical desert zone during the early to mid-Holocene.

Journal Article↗

PubMed2003

High-performance solid Acid fuel cells through humidity stabilization.

Although they hold the promise of clean energy, state-of-the-art fuel cells based on polymer electrolyte membrane fuel cells are inoperable above 100 degrees C, require cumbersome humidification systems, and suffer from fuel permeation. These difficulties all arise from the hydrated nature of the electrolyte. In contrast, "solid acids" exhibit anhydrous proton transport and high-temperature stability. We demonstrate continuous, stable power generation for both H2/O2 and direct methanol fuel cells operated at approximately 250 degrees C using a humidity-stabilized solid acid CsH2PO4 electrolyte.

Journal Article↗

PubMed2004

Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds.

In situ measurements of the relative humidity with respect to ice (RHi) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RHi values show a sharp increase to average values of over 130% in both cloud types. These enhanced RHi values are attributed to the presence of a new class of HNO3-containing ice particles (Delta-ice). We propose that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Delta-ice represents a new link between global climate and natural and anthropogenic nitrogen oxide emissions. Including Delta-ice in climate models will alter simulated cirrus properties and the distribution of upper tropospheric water vapor.

Journal Article↗

PubMed1978

Persistence of Rhizobium japonicum on the Soybean Seed Coat Under Controlled Temperature and Humidity.

When Rhizobium japonicum strain 61A68 was added to surface-sterilized soybean (Glycine max) seed along with 12 different coating materials, a definite effect of temperature upon survival was observed both with and without coating materials. At a storage temperature of 15 degrees C and 50 +/- 5% relative humidity, from 0.9 to 14.1% of the original inoculum survived for 3 weeks. At 22.5 degrees C, from 0.5 to 7.2% of the original inoculum survived. At 30 degrees C, from 0.1 to 1.6% of the original inoculum survived. The data indicated that extremely large numbers of R. japonicum would have to be added to the seed to have numbers adequate for nodulation survive for 3 weeks of storage at ordinary temperatures.

Journal Article↗

PubMed1994

Stachybotrys atra Growth and Toxin Production in Some Building Materials and Fodder under Different Relative Humidities.

Growth of Stachybotrys atra and its toxin production on some building materials and in animal fodder were studied at relative humidities ranging from 78 to 100%. Toxins were detected by biological assays and chemical methods. Strong growth of the fungus and presence of macrocyclic trichothecenes, mainly satratoxins G and H, were detected on wallpaper and gypsum boards and in hay and straw at saturation conditions. On pine panels, S. atra grew well, but neither biological toxicity nor production of macrocyclic trichothecenes was observed.

Journal Article↗

PubMed1970

Effect of relative humidity on the penetrability and sporicidal activity of formaldehyde.

The effect of relative humidity (RH) on formaldehyde penetration of paper, glassine, and cotton was determined by the death rate of bacterial spores in glass tubes covered with these materials. The data show that paper is readily penetrated regardless of RH, but the RH greatly affects the penetration rate of glassine and cotton. A comparison was also made of the effect of RH on the penetrability of formaldehyde generated from Formalin and paraformaldehyde. At low RH, all three closures were penetrated more readily by formaldehyde from paraformaldehyde than from Formalin, but no difference in the two was observed at high RH. It is felt that the difference at low RH is primarily due to the condensation of the vaporized Formalin.

Bacillus subtilis↗

PubMed2004

Optical fiber relative-humidity sensor with polyvinyl alcohol film.

We describe a fiber-optic relative-humidity (RH) sensor comprising a moisture-sensitive overlay on a single-mode side-polished fiber. The hygroscopic polymeric material deposited was polyvinyl alcohol (PVA), which proved to have good adherence and stability. The film reached a fast equilibrium with atmospheric moisture (in less than 1 min), inducing changes in the output optical power of approximately 10 dB for the 70%-90% RH range. To yield a low-cost device, single-mode standard communication fibers were used; therefore all the components of the sensor can be commercial, mass-produced telecommunication devices. The experimental results obtained are consistent with the expected behavior of the system; the output power decreases because of losses in the polished region of the fiber as the refractive index of its external medium approaches the fiber core value. Because the external medium is PVA film, its refractive index changes in response to its water content.

Journal Article↗

PubMed2006

Spaceborne profiling of atmospheric temperature and particle extinction with pure rotational Raman lidar and of relative humidity in combination with differential absorption lidar: performance simulations.

The performance of a spaceborne temperature lidar based on the pure rotational Raman (RR) technique in the UV has been simulated. Results show that such a system deployed onboard a low-Earth-orbit satellite would provide global-scale clear-sky temperature measurements in the troposphere and lower stratosphere with precisions that satisfy World Meteorological Organization (WMO) threshold observational requirements for numerical weather prediction and climate research applications. Furthermore, nighttime temperature measurements would still be within the WMO threshold observational requirements in the presence of several cloud structures. The performance of aerosol extinction measurements from space, which can be carried out simultaneously with temperature measurements by RR lidar, is also assessed. Furthermore, we discuss simulations of relative humidity measurements from space obtained from RR temperature measurements and water-vapor data measured with the differential absorption lidar (DIAL) technique.

Journal Article↗

PubMed1982

The effects of videotape modeling and daily feedback on residential electricity conservation, home temperature and humidity, perceived comfort, and clothing worn: Winter and summer.

Two studies were conducted in all-electric townhouses and apartments in the winter (N = 83) and summer (N = 54) to ascertain how energy conservation strategies focusing on thermostat change and set-backs and other low-cost/no-cost approaches would affect overall electricity use and electricity used for heating and cooling, the home thermal environment, the perceived comfort of participants, and clothing that was worn. The studies assessed the effectiveness of videotape modeling programs that demonstrated these conservation strategies when used alone or combined with daily feedback on electricity use. In the winter, the results indicated that videotape modeling and/or feedback were effective relative to baseline and to a control group in reducing overall electricity use by about 15% and electricity used for heating by about 25%. Hygrothermographs, which accurately and continuously recorded temperature and humidity in the homes, indicated that participants were able to live with no reported loss in comfort and no change in attire at a mean temperature of about 62 degrees F when home and about 59 degrees F when asleep. The results were highly discrepant with prior laboratory studies indicating comfort at 75 degrees F with the insulation value of the clothing worn by participants in this study. In the summer, a combination of strategies designed to keep a home cool with minimal or no air conditioning, in conjunction with videotape modeling and/or daily feedback, resulted in overall electricity reductions of about 15% with reductions on electricity for cooling of about 34%, but with feedback, and feedback and modeling more effective than modeling alone. Despite these electricity savings, hygrothermograph recordings indicated minimal temperature change in the homes, with no change in perceived comfort or clothing worn. The results are discussed in terms of discrepancies with laboratory studies, optimal combinations of video-media and personal contact to promote behavior change, and energy policies that may be mislabeled as sacrificial and underestimate the effectiveness of conservation strategies such as those investigated in these studies.

Journal Article↗

PubMed1994

Herbage allowance x yearling heifer phenotype interactions for preweaning calf growth on humid pasture and semiarid rangeland.

Preweaning growth data were obtained during 4 yr on 349 Braford-sired calves from Brahman-Hereford F1 first-calf females. These females were allotted to either semiarid rangeland (Uvalde) or humid improved pasture (Overton) as weanlings and to one of four herbage allowance levels at each location as yearlings. Females were wintered on systems in local industry practice and maintained on various allotted herbage levels both as yearlings and during first lactation. The desired range in herbage allowance (400 to 2,800 kg of DM per 100 kg of BW at Uvalde and 80 to 460 kg of DM per 100 kg of BW at Overton) was accomplished by adjusting stocking rate monthly from April to weaning (October). Herbage allowance and yearling heifer characteristics (hook height, condition score, or weight) were treated as continuous, independent variables in regression analyses. Preweaning daily gain responded to increased herbage allowance differently for the two locations. Generally, at Overton, herbage allowance influenced suckling calf growth to a greater extent than for the F1 yearling variables, but at Uvalde this trend was reversed. Heifers with larger yearling heights had first calves that grew faster to weaning for both locations and all herbage allowances, although the relationship was stronger for greater herbage allowances at Overton (herbage allowance x yearling weight interaction, P < .07). This interaction was not detected (P > .15) at Uvalde. Interactions between herbage allowance and yearling condition score were detected (P < .05) at both Overton and Uvalde, but these interactions were different (P < .15) at the two locations.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1989

A pragmatic approach to improving small ruminant diets in the Indonesian humid tropics.

Research conducted since 1980 on the nutrition and feeding of Kacang goats and Javanese Thintail sheep for meat production in Indonesia is reviewed. Feeding practices in three villages were monitored, along with animal production criteria, to better understand the limitations imposed by feed resource availability. Village and experiment station data showed that native or cultivated tropical grasses fed alone did not support growth of young goats and that lambs fed napier grass alone grew at no more than 20 to 25 g/d. Supplementing these grasses with tree legume foliage or wilted cassava leaves at modest levels improved ADG to about 50 g for lambs and 20 g for kids. Faster gains were obtained with higher intakes of tree legume foliage, or with combinations of higher-energy supplements such as rice bran, cassava meal and molasses. A response to mineral supplementation also was shown. Reproductive performance of North Sumatran ewes grazing a native pasture under rubber trees also was improved with supplementation. These experiments show that economically effective options exist for improving small ruminant diets in the humid tropics.

Animal Feed↗

PubMed2026

Assessing the genetic potential of a milk mid-infrared prediction of heat stress response in dairy cows using a temperature-humidity index-independent approach.

Selection for heat tolerance remains challenging due to the difficulty of accessing reliable phenotypes at large scale. An alternative could be established using mid-infrared spectra, which are collected routinely through milk recording, and have already shown their value as proxies for a variety of phenotypes that are costly or difficult to measure. Recently, a first prediction of heat stress response in dairy cows based solely on milk mid-infrared spectra was developed. This prediction was obtained using models calibrated on surface body temperature and milk composition variations. Its potential as a detection tool was explored, but no genetic analyses has been performed. On this basis, the objectives of this study were to estimate the heritability of the predicted heat stress response, assess its genetic correlations with traits from the Walloon official genetic evaluation, and identify genomic regions associated with heat tolerance through a GWAS, all without using temperature-humidity index (THI) information. The estimated heritability (0.10) was low but sufficient to enable genetic selection and consistent with expectations for a heat stress-related trait. Also as expected, an antagonistic relationship between heat tolerance and milk production was observed, but its extent was notably reduced compared with traditional approaches. In addition, genetic correlations with other traits were neutral (fat yield) or favorable (protein yield, SCS, fertility, longevity). Concerning the GWAS, genomic regions and candidate genes previously associated with the response to heat stress were highlighted, as well as others related to energy balance maintenance. Overall, these results support the relevance of the prediction for the heat stress response as a new phenotype for heat tolerance selection that does not require any THI information. They also reinforce the importance of energy balance for dairy cows to cope with heat stress.

Journal Article↗

PubMed2000

[Distribution and transferring of carbon in kast soil system of peak forest depression in humid subtropical region].

Taking Guilin Yaji Karst Experiment Site as an exemple and with the methods of field monitoring and laboratory analysis, this paper studied the distribution and transferring of carbon in the karst soil system of peak forest depression in the humid subtropical region of China. The carbon pools in biomass, litters and soil organic matter(SOM) and their mobility as expressed by oxidizability and decomposition rate of SOM, the concentration of soil CO2 and the emission rate of CO2 from soil were investigated. The mobile carbon pool in the system supplied a rich source of CO2, which drived the karst process. When active karst process happened in Spring and Summer, over 60% of carbon in the output water was derived from soil CO2, as traced by delta 13 C distribution in the system. Therefore, owing to the carbon transfer in the pathway of air-plant-soil-water, karst process took place rather under soil-rock-water interface than under air-rock-water interface. Thus, the epigenetic karst process was driven and accelerated by soil as an interface of carbon environmental geochemistry.

Carbon↗

PubMed1975

Influence of salts on the microbial activities in arid and semi-humid soils.

The influence of salt mixtures consisting of Ca(H2PO4)2, trace elements, CaSO4, CaCO3, Na2CO3, NaCl and K2SO4 in different combinations on the nitrifying power, evolution of carbon dioxide and the total number of bacteria was studied in arid soils (sandy and alluvial) and semi-humid ones (chernozem and rendzina). Salt mixtures comprising of either mono-calcium phosphate or sodium chloride showed highly inhibiting action on the studied microbial activities in sandy, alluvial and chernozem soils, whilst mono-calcium phosphate stimulated the heterotrophs of rendzina. Trace elements stimulated the autotrophs of the clay soils. The other different salts mixtures acted according to the salt combination and nature of the microbial activity.

Bacteria↗

PubMed1994

Effect of temperature and humidity on the disintegration time of packaged paracetamol tablet formulations.

A study of the effect of various temperature and humidity conditions on the disintegration time of different brands of packaged paracetamol tablet formulations has been made over a period of six months. Under all the storage conditions paracetamol tablets show an increase in disintegration time ranging from 9.1 to 65.5% (200 mg tablets) and 1.2 to 150.0% (500 mg tablets) on increasing the temperature from 25 to 45 degrees C (75% RH). The increase in disintegration time on increasing the temperature from 25 to 45 degrees C (100% RH) ranges from 14.3 to 157.7% (200 mg tablets) and 15.3 to 92.3% (500 mg tablets). The overall increase in disintegration time from 25-45 degrees C at 75% and 100% RH is 36.4 to 564% (200 mg tablets) and 10.0 to 140.5% (500 mg tablets) and 101.3 to 122.9% (200 mg tablets) and 2.6 to 46.8% (500 mg tablets) respectively. These results indicate that PVC/PVDC/Al foil packaging cause relatively less change in disintegration time of the tablets compared to that of the polycoated paper and viscose film.

Journal Article↗

PubMed2006

Evaluation of water binding, seed coat permeability and germination characteristics of wheat seeds equilibrated at different relative humidities.

The relative binding of seed water and seed coat membrane stability were measured in two contrasting wheat (Triticum aestivum L) varieties, HDR 77 (drought-tolerant) and HD 2009 (susceptible) using seed water sorption isotherms, electrical conductivity (EC) of leachates and desorption-absorption isotherms. Analysis of sorption isotherm at 25 degrees C showed that the seeds of HDR 77 had significantly higher number of strong binding sites, with correspondingly greater amount of seed water as strongly bound water, as compared to HD 2009. Total number of binding sites was also higher in HDR 77 than HD 2009, which explained the better desiccation tolerance and higher capacity to bind water in seeds of HDR 77. EC of seed leachate in both varieties did not change with respect to change in equilibrium relative humidity (RII), indicating the general seed coat membrane stability of wheat seeds. However, absolute conductivity values were higher for HD 2009. showing its relatively porous seed coat membrane. Significantly lower area enclosed by the desorption-absorption isotherm loop in HDR 77, as compared to HD 2009 also indicated the greater membrane integrity of HDR 77. Germination and seedling vigour of HD 2009 were reduced when equilibrated over very low and very high RH. In contrast, germination and vigour in HDR 77 were maintained high, except at very high RH, indicating again its desiccation tolerance. Thus, the study demonstrated the relative drought tolerance of HDR 77, on the basis of seed water-binding characteristics and seed membrane stability. Seed membrane stability as measured by seed leachate conductivity or as area under dehydration-rehydration loop may be used as a preliminary screening test for drought tolerance in wheat.

Absorption↗

PubMed2006

[Plant biodiversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stages].

To analyze the relationships between plant diversity and community structure of semi-humid evergreen broadleaved forests at different secondary succession stage in the Samachang area of Yunnan Province, some numeral indices were tested, and the results showed that the plant diversity increased gradually with succession, and the species number reached 24 at the latest succession stage. There was a positive linear correlation between plant individual density and species diversity, which could be described by y = 506. 99x + 554.56. A negative correlation was observed between the average height of plant individuals and plant species diversity, and the equation y = -0. 3862x + 11.406 could describe it well. The crown density and basal area increased in logarithm with plant species diversity, and the two equations y = 21.756 1n x + 11.607 and y = 7.4028 ln x + 9.6198 could describe the relations. No regular patterns were observed for the changes of aboveground biomass and plant individual density with plant species diversity. The relations of plant species with plant individual number could also be described by negative power function. Plant competition was intensified with plant species diversity, and each plant species might take the strategy to conserve its greatest population, and to avoid decreasing to less than its critical population, which led to a high individual density, and might change the structural character of the community.

Biodiversity↗