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Results for “TROPICAL CLIMATE”

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At least 55 records · Page 3Linked to original sources
PubMed1981

Plasma cortisol in Bos taurus and Bos indicus heifers in seasonal tropical climate.

Cortisol concentration in blood plasma was measured in Brown Swiss, Holstein-Friesian, and White Fulani heifers over two consecutive estrous cycles during each of the four quarters of the hot humid seasonal tropical climate of Ibadan, Southern Nigeria. Basal cortisol in plasma was low (between 1 and 10 ng/ml). Differences between breeds were not significant. Averages and increases with proestrus and estrus were higher in the wet season (March to August) than in the dry season (November to January). Packed cells volume was higher in the dry season than in the wet season. Seasonal changes in rhythmicity of the estrous cycle were not significant. The low cortisol in plasma probably reflects adaptation to the hot climate and a mechanism to prevent high metabolic heat.

Adrenal Cortex↗
PubMed2005

Treatment of septage in constructed wetlands in tropical climate: lessons learnt from seven years of operation.

In tropical regions, where most of the developing countries are located, septic tanks and other onsite sanitation systems are the predominant form of storage and pre-treatment of excreta and wastewater, generating septage and other types of sludges. The septage is disposed of untreated, mainly due to lack of affordable treatment options. This study presents lessons that have been learned from the operation of pilotscale constructed wetlands (CWs) for septage treatment since 1997. The experiments have been conducted by using three CW units planted with narrow-leave cattails (Typha augustifolia) and operating in a vertical-flow mode. Based on the experimental results, it can be suggested that the optimum solids loading rate be 250 kg TS/m2 yr and 6-day percolate impoundment. At these operational conditions, the removal efficiencies of CW units treating septage at the range of 80-96% for COD, TS and TKN were achieved. The biosolid accumulated on the CW units to a depth of 80 cm has never been removed during 7 years of operation, but bed permeability remained unimpaired. The biosolid contains viable helminth eggs below critical limit of sludge quality standards for agricultural use. Subject to local conditions, the suggested operational criteria should be reassessed at the full-scale implementation.

Agriculture↗
PubMed1992

Sleep patterns of European expatriates in a dry tropical climate.

Night sleep in sedentary African subjects living in the sahelian zone lasts from 7 h to 8 h, with high amounts of slow-wave sleep (SWS) and paradoxical sleep (PS), SWS being present in each sleep cycle. We report here on sleep patterns in 6 healthy male European expatriates (aged 32-39 years) living in the same tropical climate. Polysomnography was taken for 3 consecutive nights in February (mean ambient temperature, Ta: 29.5 degrees C), March (Ta: 31.6 degrees C) and May (Ta: 33.3 degrees C). Comparisons between seasons were made with an analysis of variance, with P >/= 0.05. Because of a first night effect, the first nocturnal recording was discarded. Total sleep time (TST) increased in May vs February and March (P < 0.05). Stage 2 was shorter in March than in February (P < 0.001) and its proportion decreased from February to March (P < 0.02) and from March to May (P < 0.05). Conversely, SWS increased from February to March and March to May (duration, P < 0.001; proportion, P < 0.05), due to an augmentation in stage 4 with more numerous and longer stage 4 phases. Stage 3 was also increased in May vs March. The latency to SWS was shorter in March. SWS was present in each sleep cycle. PS was high, but did not vary. The sleep pattern changes were directly correlated with Ta. In conclusion, Caucasians living in the tropics slept similarly to Africans. The seasonal sleep variations favour the hypothesis that SWS is increased when thermoregulatory processes are triggered, either through passive climatic heating or exercise-induced hyperthermia.

Journal Article↗
PubMed2002

Evaluation of the potentialities to reduce greenhouse gases (GHG) emissions resulting from various treatments of municipal solid wastes (MSW) in moist tropical climates: application to Yaounde.

The authors here analyse the emission of greenhouse gases (GHG) resulting from the various treatment of municipal solid waste found in the town of Yaounde. Four management systems have been taken as the basis for analyses. System 1 is the traditional collection and landfill disposal, while in system 2 the hiogas produced in the landfill is recuperated to produce electricity. In systems 3 and 4, in addition to the collection, we have introduced a centralised composting or biogas plant before the landfilling disposal of refuse. A Life Cycle Inventory (LCI) of the four systems was made; this enable us to quantify the flux of matter and of energy, consumed or produced by the systems. Following this, only the greenhouse effect was taken into account to evaluate the ecological consequences of the MSW management systems. The method used to evaluate this impact takes into consideration on the one hand, GHG emissions or avoided emission following the substitution of fuel with methane recovered from landfills or produced in the digesters, and on the other hand, sequestrated carbon in the soil following the regular deposit of compost. Landfilling without recuperation of methane is the most emitting solution for greenhouse gas: it leads to the emission of 1.7 ton of carbon dioxide equivalent (tCO2E) per ton of household waste. Composting and methanisation allow one to have a comparable level of emission reduction, either respectively 1.8 and 2 tCO2E/t of MSW. In order to reduce the emission of GHG in the waste management systems, it is advisable to avoid first of all the emissions of methane coming from the landfills. System 2 seems to be a solution that would reduce the emissions of GHG at low cost (2.2 to 4 $/tCO2E). System 2 is calculated as the most effective at the environmental and economic level in the context of Yaounde. Therefore traditional collection, landfill disposal and biogas recuperation to produce electricity is preferable in moist tropical climates.

Air Pollution↗
PubMed1997

[Tropical climate pathology].

In addition to being a determinant factor for the development of infectious and parasitic diseases, tropical weather conditions can have harmful effects for the human organism different from those of temperate climates. Adverse effects can result from aggressive environmental factors such as ultraviolet radiation, extreme heat, abrupt changes in temperature, and tropical storms. In weather-sensitive subjects, exposure to tropical conditions increases the risk of acute reactions including ischemic heart disease, asthma attacks, and kidney stones. Adverse effects can be enhanced by suddenness of change in climate as underlined by the stress experienced by air travelers. In practice it is important to recognize that different tropical climates have different effects on health. Intertropical climates range from dry and rainy areas to plains and mountain areas. Knowledge of the concepts of climatopathology is necessary to advise patients on the choice of destination and the most favorable period for travel.

Asthma↗