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At least 19 recordsLinked to original sources
PubMed1976

[Effect of tropical climate on the androgenic activity of various strains of bulls].

By means of experiments the effect of a tropical climate on the androgenic activity of bulls expressed by the fructose level in the sperm was proved as well as a direct dependence of its concentration on the volume of the ejaculate and an indirect dependence on the density of spermatozoa. Besides this also its positive relation to the vitamin C level and to the polarographic and hemolytic activity of the sperm was proved. From the results obtained the conclusion has been drawn that the androgens affect the protein, vitamin and enzymic structures of the sperm.

Androgens↗
PubMed1979

Seasonal effects of tropical climate on shaded and nonshaded cows as measured by rectal temperature, adrenal cortex hormones, thyroid hormone, and milk production.

Rectal temperatures and hormone concentrations were monitored at intervals of 2 to 3 weeks, and milk, milk fat, and California mastitis test scores at intervals of 1 week in five shaded and in four nonshaded early lactation cows. Measurements were taken from September to December in the mildly heat stressing climate of Oahu, Hawaii. The daily ambient temperature flux ranged from 22 C to 29 C in September to 20 C to 25 C in December. Average daily temperature-humidity index (THI) values were 75 to 70 for September and December, respectively. Average daily THI values were correlated with rectal temperatures in nonshaded cows and were negatively correlated with plasma adrenal cortex hormones (corticoids) in shaded cows, plasma thyroid hormone in shaded and nonshaded cows, and with milk production in nonshaded cows. Estimated milk production decline per unit increase in THI was 0.32 kg. Nonshaded cows had higher rectal temperatures, a trend for lower plasma corticoids, produced less milk and milk fat, and had higher California mastitis test scores. Shaded cows maintained a higher fat percentage at THI above 74. Average plasma thyroid hormone values were not different between treatment groups. Both groups failed to attain normal rectal temperatures at night. Afternoon rectal temperatures were more highly correlated with the rectal temperature with which the cow started the day than they were with the THI of the day itself.

Adrenal Cortex Hormones↗
PubMed1977

The shelf life of some antibiotic preparations stored under tropical conditions.

Accelerated storage tests have been carried out to predict the shelf life of several commercial preparations stored directly under temperate and tropical climatic conditions. Two brands each of sulphathiazole tablets, tetracycline hydrochloride capsules and chloramphenicol capsules were studied over a period of three months. Shelf lives ranging from 6.2. to 29.7 months were predicted for temperate storage conditions (20 degree C/31% R.H.), whilst these periods were reduced giving values from 3.8 to 13.9 months for tropical conditions of 30 degree C/31% R.H and from 2.5 to 9.2. months when stored at 30 degree C/75% R.H. A decrease in the rate of drug dissolution was also observed for preparations stored directly under conditions of elevated temperature and humidity. The results indicate the need for stringent control over storage conditions for antibiotic preparations in tropical climates to ensure adequate drug stability and dissolution characteristics.

Anti-Bacterial Agents↗
PubMed1977

Comparison of physical characteristics, body temperature and basal metabolism between Thai and Japanese in a neutral temperature zone.

The aim of this research is to compare the physical status, basal metabolism and some other physiological characteristics between native Thai in Bangkok, Thailand, and native Japanese in Japan, and discuss the results regarding acclimatization to tropical climate. Measurements of the Thai were made in September in Bangkok, while those of native Japanese were done in August at Nishinomiya (Japan). The subjects were adult males (20-22 years old) in both cases. Physically the Thai are generally a little shorter and more slender than Japanese in the mean value. The mean skinfold thickness for Thai was 8.4 mm, which is significantly less than that of Japanese (11.0 mm). The mean oral temperature measured under basal conditions was the same between both subject groups. The Thai showed a slightly lower basal metabolism per unit body surface, and mean skin temperature measured in a similar environmental condition was lower for Thai than for Japanese. The results of anthropometric measurements and physiological characteristics measured were discussed in view of physiology of acclimatization ot tropical climate.

Acclimatization↗
PubMed1979

Biochemical changes of normal pregnancy and puerperium in Lagos, Nigeria.

A cross-sectional study is presented of biochemical changes in the third trimester of normal pregnancy and puerperium during the wet season in the tropical climate of Lagos, Nigeria. These changes are less marked in first than in subsequent pregnancies, and although qualitatively similar, in some respects they differ from those observed in the temperate climatic zone. The indications are that quantitative differences may exist which could be relevant to the management of pregnancy in the tropics.

Adult↗
PubMed1976

Forest to pasture: development or destruction?

The expansion of artifical or planted pastures (repasto) at the expense of both natural forest and cropland has brought major changes to the landscape and economy of Central America in recent years. On the pioneer fronts at the forest margin agriculture is commonly a transitory stage between forest felling and the establishment of permanent pasture. In the past 15 years the area in planted pasture and the total numbers of beef cattle have nearly doubled in several Central American countries while the per capita consumption of beef has actually declined. The "grassland revolution" that is occuring in Central America and Panama has been based almost exclusively on grass species of African origin which have in most cases been introduced into Central America only in this century. Of these jaragua, guinea, pangola, and kikuyu are the most important. The ecologic consequences of the conversion of forest to pasture are little understood. Intensive management practices, including the application of high-cost and scarce fertilizers and carefully-manged rotational grazing, will probably be necessary to sustain the productivity of these lands under conditions of tropical climate.

Agriculture↗
PubMed1976

The effects of climatic patterns and agricultural practices on the population dynamics of Culex tritaeniorhynchus in Asia.

Annual population curves for C. tritaeniorhynchus are presented for representative localities distributed from Pakistan, east through Southeast Asia and the Philippines and north to Japan and Korea. In the dry temperature (Pakistan) and colder maritime climates (Japan and Korea). C. tritaeniorhynchus populations apparently overwintered as hibernating adults, while in the warmer maritime climates (Okinawa and Taiwan), gonotrophic activity and larval development continued throughout the winter months. In these climatic types, the population curves closely paralleled the annual temperature curves. In the tropical climates, however, temporal population patterns were closely related to available moisture either in the form of annual precipitation and/or rice irrigation. The extremely variable environmental conditions tolerated C. tritaeniorhynchus throughout its distribution attests to the physiological and ecological plasticity of this species and suggests that further ecological and genetic studies may reveal marked clinical variances among selected biological parameters.

Agriculture↗
PubMedDate not supplied

[Risk groups in travel to tropical countries within the frame of mass tourism].

More than 10,000 tourists returning from tropical countries have been asked about health problems during their stay abroad. Preliminary results from the first 5,550 questionnaires indicate that 74,8% had complaints of any kind concerning their health and 13,6% can be considered as having been ill. The frequency of complaints and illness in relation to different variables is shown and the possibility of definition of high risk groups is being discussed.

Adolescent↗
PubMed2026

Allelic variation in UVR8 modulates thermotolerance-yield tradeoffs in plants.

Industrial activities have driven stratospheric ozone depletion, increasing surface UV-B radiation while exacerbating global warming. These changes limit crop productivity, alter species distributions, and disrupt plant metabolic processes, but the mechanisms linking energy signaling to heat-stress responses remain unclear. Here, we identify the photoreceptor UV RESISTANCE LOCUS 8b (OsUVR8b) as a substrate of SNF1-related protein kinase 1 (SnRK1) in rice and reveal a natural variation at its SnRK1-mediated phosphorylation site (Ser177) that is correlated with adaptation to tropical climates. The thermotolerant OsUVR8bAla177 accessions show geographic enrichment in low-latitude regions with elevated temperatures. Functional validation through prime editing demonstrated that a Ser177-to-Ala177 substitution enhances heat tolerance, whereas the reverse edit compromises it. Mechanistically, OsUVR8bSer177 exhibits reduced stability and an impaired capacity for scavenging reactive oxygen species under heat stress. The regulatory function of the OsUVR8b Ser177 phosphorylation site, a molecular switch that governs UVR8 stability and thermotolerance, can be functionally re-established across rice, Arabidopsis, tobacco, and soybean, indicating its preservation during domestication. Notably, OsUVR8bSer177 maintains higher fertility and yield under non-stress conditions, indicating a tradeoff between heat adaptation and productivity. Our findings thus establish this switch as a key regulator of the yield-resilience balance and a promising target for breeding of climate-resilient crops.

Thermotolerance↗