Displaying publications 81 - 100 of 298 in total

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  1. Nwunuji TP, Mayowa OO, Yusoff SM, Bejo SK, Salisi S, Mohd EA
    Anim. Sci. J., 2014 May;85(5):611-6.
    PMID: 24612236 DOI: 10.1111/asj.12174
    The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty-four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post-transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity.
    Matched MeSH terms: Tropical Climate*
  2. Tripathi BM, Kim M, Lai-Hoe A, Shukor NA, Rahim RA, Go R, et al.
    FEMS Microbiol. Ecol., 2013 Nov;86(2):303-11.
    PMID: 23773164 DOI: 10.1111/1574-6941.12163
    Little is known of the factors influencing soil archaeal community diversity and composition in the tropics. We sampled soils across a range of forest and nonforest environments in the equatorial tropics of Malaysia, covering a wide range of pH values. DNA was PCR-amplified for the V1-V3 region of the 16S rRNA gene, and 454-pyrosequenced. Soil pH was the best predictor of diversity and community composition of Archaea, being a stronger predictor than land use. Archaeal OTU richness was highest in the most acidic soils. Overall archaeal abundance in tropical soils (determined by qPCR) also decreased at higher pH. This contrasts with the opposite trend previously found in temperate soils. Thaumarcheota group 1.1b was more abundant in alkaline soils, whereas group 1.1c was only detected in acidic soils. These results parallel those found in previous studies in cooler climates, emphasizing niche conservatism among broad archaeal groups. Among the most abundant operational taxonomic units (OTUs), there was clear evidence of niche partitioning by pH. No individual OTU occurred across the entire range of pH values. Overall, the results of this study show that pH plays a major role in structuring tropical soil archaeal communities.
    Matched MeSH terms: Tropical Climate*
  3. Chong TM, Koh CL, Sam CK, Choo YM, Yin WF, Chan KG
    Sensors (Basel), 2012;12(4):4846-59.
    PMID: 22666062 DOI: 10.3390/s120404846
    We report the production and degradation of quorum sensing N-acyl-homoserine lactones by bacteria isolated from Malaysian montane forest soil. Phylogenetic analysis indicated that these isolates clustered closely to the genera of Arthrobacter, Bacillus and Pseudomonas. Quorum quenching activity was detected in six isolates of these three genera by using a series of bioassays and rapid resolution liquid chromatography analysis. Biosensor screening and high resolution liquid chromatography-mass spectrometry analysis revealed the production of N-dodecanoyl-L-homoserine lactone (C12-HSL) by Pseudomonas frederiksbergensis (isolate BT9). In addition to degradation of a wide range of N-acyl-homoserine lactones, Arthrobacter and Pseudomonas spp. also degraded p-coumaroyl-homoserine lactone. To the best of our knowledge, this is the first documentation of Arthrobacter and Pseudomonas spp. capable of degrading p-coumaroyl-homoserine lactone and the production of C12-HSL by P. frederiksbergensis.
    Matched MeSH terms: Tropical Climate*
  4. Usman MG, Rafii MY, Martini MY, Oladosu Y, Kashiani P
    J. Sci. Food Agric., 2017 Mar;97(4):1164-1171.
    PMID: 27290898 DOI: 10.1002/jsfa.7843
    BACKGROUND: Studies on genotypic and phenotypic correlations among characters of crop plants are useful in planning, evaluating and setting selection criteria for the desired characters in a breeding program. The present study aimed to estimate the phenotypic correlation coefficients among yield and yield attributed characters and to work out the direct and indirect effects of yield-related characters on yield per plant using path coefficient analysis. Twenty-six genotypes of chili pepper were laid out in a randomized complete block design with three replications.

    RESULTS: Yield per plant showed positive and highly significant (P ≤ 0.01) correlations with most of the characters studied at both the phenotypic and genotypic levels. By contrast, disease incidence and days to flowering showed a significant negative association with yield. Fruit weight and number of fruits exerted positive direct effect on yield and also had a positive and significant (P ≤ 0.01) correlation with yield per plant. However, fruit length showed a low negative direct effect with a strong and positive indirect effect through fruit weight on yield and had a positive and significant association with yield.

    CONCLUSION: Longer fruits, heavy fruits and a high number of fruits are variables that are related to higher yields of chili pepper under tropical conditions and hence could be used as a reliable indicator in indirect selection for yield. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Tropical Climate*
  5. Awad EA, Zulkifli I, Soleimani AF, Loh TC
    Poult. Sci., 2015 Nov;94(11):2772-7.
    PMID: 26371331 DOI: 10.3382/ps/pev258
    A study was conducted to investigate the effects of feeding low-protein diets fortified with individual non-essential amino acids (NEAA) on growth performance, serum metabolites (uric acid, UA; triglycerides, TG; total protein, TP; and albumin, Alb), organ weight, breast yield, and abdominal fat weight in broiler chicks raised under the hot and humid tropical climate. Eight isocaloric (3,017 kcal/kg) experimental diets were formulated and fed to male broiler chicks from d 1-21 as follows: 1) 22.2% crude protein (CP) (positive control; PC); 2) 16.2% CP + mixture essential amino acids (EAA) to meet or exceed the National Research Council (1994) recommendations (negative control; NC); 3) NC + glycine (Gly) to equal the total glycine + serine level in the PC; diets 4 through 7 were obtained by supplementing NC diet with individual glutamic acid, proline, alanine, or aspartic acid (Glu, Pro, Ala, or Asp, respectively); 8) NC + NEAA (Gly + Glu + Pro + Ala + Asp) to equal the total level of these NEAA in the PC. Fortifying NC diet with mixture NEAA resulted in a similar growth performance as PC. However, fortification of low-CP diet with individual NEAA failed to improve body weight (BW) (P < 0.0001), feed intake (FI) (P = 0.0001), and feed conversion ratio (FCR) (P = 0.0001). Serum uric acid (UA) was lower (P = 0.0356) in NC birds and NC diet supplemented with individual NEAA birds, whereas serum triglyceride (TG) (P = 0.007) and relative weight of abdominal fat (P = 0.001) were higher in these birds. In conclusion, no single NEAA fortification may compensate the depressed growth performance attributed to a low-CP diet. However, fortification with Gly may improve FCR. There is a possibility that broilers raised under the hot and humid climate require higher Gly fortification than the level used in this study.
    Matched MeSH terms: Tropical Climate*
  6. Martin TE
    Science, 2015 Aug 28;349(6251):966-70.
    PMID: 26315435 DOI: 10.1126/science.aad1173
    Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds.
    Matched MeSH terms: Tropical Climate*
  7. Merckx VS, Hendriks KP, Beentjes KK, Mennes CB, Becking LE, Peijnenburg KT, et al.
    Nature, 2015 Aug 20;524(7565):347-50.
    PMID: 26266979 DOI: 10.1038/nature14949
    Tropical mountains are hot spots of biodiversity and endemism, but the evolutionary origins of their unique biotas are poorly understood. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere. Here we investigate the evolutionary routes to endemism by sampling an entire tropical mountain biota on the 4,095-metre-high Mount Kinabalu in Sabah, East Malaysia. We discover that most of its unique biodiversity is younger than the mountain itself (6 million years), and comprises a mix of immigrant pre-adapted lineages and descendants from local lowland ancestors, although substantial shifts from lower to higher vegetation zones in this latter group were rare. These insights could improve forecasts of the likelihood of extinction and 'evolutionary rescue' in montane biodiversity hot spots under climate change scenarios.
    Matched MeSH terms: Tropical Climate*
  8. Tsukahara Y, Oishi K, Hirooka H
    J. Anim. Sci., 2011 Dec;89(12):3890-907.
    PMID: 21705639 DOI: 10.2527/jas.2011-3997
    A deterministic simulation model was developed to estimate biological production efficiency and to evaluate goat crossbreeding systems under tropical conditions. The model involves 5 production systems: pure indigenous, first filial generations (F1), backcross (BC), composite breeds of F1 (CMP(F1)), and BC (CMP(BC)). The model first simulates growth, reproduction, lactation, and energy intakes of a doe and a kid on a 1-d time step at the individual level and thereafter the outputs are integrated into the herd dynamics program. The ability of the model to simulate individual performances was tested under a base situation. The simulation results represented daily BW changes, ME requirements, and milk yield and the estimates were within the range of published data. Two conventional goat production scenarios (an intensive milk production scenario and an integrated goat and oil palm production scenario) in Malaysia were examined. The simulation results of the intensive milk production scenario showed the greater production efficiency of the CMP(BC) and CMP(F1) systems and decreased production efficiency of the F1 and BC systems. The results of the integrated goat and oil palm production scenario showed that the production efficiency and stocking rate were greater for the indigenous goats than for the crossbreeding systems.
    Matched MeSH terms: Tropical Climate*
  9. Tamrin SB, Jamalohdin MN, Ng YG, Maeda S, Ali NA
    Ind Health, 2012;50(2):156-63.
    PMID: 22293728
    The objectives of this study are to determine the prevalence of hand-arm vibration syndrome (HAVS) and the characteristics of the vibrotactile perception threshold (VPT) among users of hand-held vibrating tools working in a tropical environment. A cross sectional study was done among 47 shipyard workers using instruments and a questionnaire to determine HAVS related symptoms. The vibration acceleration magnitude was determined using a Human Vibration Meter (Maestro). A P8 Pallesthesiometer (EMSON-MAT, Poland) was used to determine the VPT of index and little finger at frequencies of 31.5 Hz and 125 Hz. The mean reference threshold shift was determined from the reference threshold shift derived from the VPT value. The results show a moderate prevalence of HAVS (49%) among the shipyard workers. They were exposed to the same high intensity level of HAVS (mean = 4.19 ± 1.94 m/s(2)) from the use of vibrating hand-held tools. The VPT values were found to be higher for both fingers and both frequencies (index, 31.5 Hz = 110.91 ± 7.36 dB, 125 Hz = 117.0 ± 10.25 dB; little, 31.5 Hz = 110.70 ± 6.75 dB, 125 Hz = 117.71 ± 10.25 dB) compared to the normal healthy population with a mean threshold shift of between 9.20 to 10.61 decibels. The frequency of 31.5 Hz had a higher percentage of positive mean reference threshold shift (index finger=93.6%, little finger=100%) compared to 125 Hz (index finger=85.1%, little finger=78.7%). In conclusion, the prevalence of HAVS was lower than those working in a cold environment; however, all workers had a higher mean VPT value compared to the normal population with all those reported as having HAVS showing a positive mean reference threshold shift of VPT value.
    Matched MeSH terms: Tropical Climate*
  10. Ng KH, McLean ID
    Semin Musculoskelet Radiol, 2011 Nov;15(5):441-5.
    PMID: 22081279 DOI: 10.1055/s-0031-1293490
    An estimated two thirds of the world's population is currently without access to diagnostic radiology services, and most of them live in resource-limited tropical regions with harsh environments. Most patients are diagnosed and treated in poorly equipped government-funded hospitals and clinics that have insufficiently trained staff and are barely operational. Any available imaging equipment is likely to be functioning suboptimally and be poorly maintained. The root of the problem is usually a lack of know-how and a quality culture, combined with insufficient basic equipment and infrastructure. Radiological imaging is an essential aspect of primary care and used in the critical diagnosis and management of trauma, tuberculosis, pneumonia, acquired immunodeficiency syndrome, cancer, and other respiratory and abdominal diseases. Considerations such as quality management and infrastructure, personnel, equipment, and radiation protection and safety are important to ensure the proper functioning and rational use of a diagnostic radiology facility in the tropics.
    Matched MeSH terms: Tropical Climate*
  11. Paynter S, Ware RS, Weinstein P, Williams G, Sly PD
    Lancet, 2010 Nov 27;376(9755):1804-5.
    PMID: 21111894 DOI: 10.1016/S0140-6736(10)62141-1
    Matched MeSH terms: Tropical Climate*
  12. How YF, Lee CY
    Med. Vet. Entomol., 2010 Jun;24(2):108-16.
    PMID: 20202109 DOI: 10.1111/j.1365-2915.2010.00852.x
    This study examined the fecundity, oviposition, nymphal development and longevity of field-collected samples of the tropical bedbug, Cimex hemipterus (Fabricius) (Hemiptera: Cimicidae). Under environmental conditions of 26+/-2 degrees C, 70 +/- 5% relative humidity and a 12-h photoperiod, with bloodmeals provided by a human host, six strains of tropical bedbug had a fecundity of up to 50 eggs per lifetime, over 11-14 oviposition cycles. Increased feeding frequency improved fecundity. After feeding and mating, adult females normally took 2-3 days to produce a first batch of eggs. The oviposition period lasted 2-7 days before cessation of the oviposition cycle. The egg incubation period usually lasted 5-7 days before the emergence of first instars. The nymphs underwent five stadia (the first four of which each took 3-4 days, whereas the last took 4-5 days) before becoming adults at a sex ratio of 1 : 1. More than five bloodmeals were required by the nymphs to ensure a successful moult. Unmated adults lived significantly longer than mated adults (P < 0.05). Unmated females lived up to almost 7 months, but the longevity of mated males and females did not differ significantly (P > 0.05).
    Matched MeSH terms: Tropical Climate*
  13. Saha M, Togo A, Mizukawa K, Murakami M, Takada H, Zakaria MP, et al.
    Mar. Pollut. Bull., 2009 Feb;58(2):189-200.
    PMID: 19117577 DOI: 10.1016/j.marpolbul.2008.04.049
    We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concentrations in urban areas (Sigma PAHs: approximately 1000 to approximately 100,000 ng/g-dry) than in rural areas ( approximately 10 to approximately 100g-dry), indicating large sources of PAHs in urban areas. To distinguish petrogenic and pyrogenic sources of PAHs, we calculated the ratios of alkyl PAHs to parent PAHs: methylphenanthrenes to phenanthrene (MP/P), methylpyrenes+methylfluoranthenes to pyrene+fluoranthene (MPy/Py), and methylchrysenes+methylbenz[a]anthracenes to chrysene+benz[a]anthracene (MC/C). Analysis of source materials (crude oil, automobile exhaust, and coal and wood combustion products) gave thresholds of MP/P=0.4, MPy/Py=0.5, and MC/C=1.0 for exclusive combustion origin. All the combustion product samples had the ratios of alkyl PAHs to parent PAHs below these threshold values. Contributions of petrogenic and pyrogenic sources to the sedimentary PAHs were uneven among the homologs: the phenanthrene series had a greater petrogenic contribution, whereas the chrysene series had a greater pyrogenic contribution. All the Indian sediments showed a strong pyrogenic signature with MP/P approximately 0.5, MPy/Py approximately 0.1, and MC/C approximately 0.2, together with depletion of hopanes indicating intensive inputs of combustion products of coal and/or wood, probably due to the heavy dependence on these fuels as sources of energy. In contrast, sedimentary PAHs from all other tropical Asian cities were abundant in alkylated PAHs with MP/P approximately 1-4, MPy/Py approximately 0.3-1, and MC/C approximately 0.2-1.0, suggesting a ubiquitous input of petrogenic PAHs. Petrogenic contributions to PAH homologs varied among the countries: largest in Malaysia whereas inferior in Laos. The higher abundance of alkylated PAHs together with constant hopane profiles suggests widespread inputs of automobile-derived petrogenic PAHs to Asian waters.
    Matched MeSH terms: Tropical Climate*
  14. Duncan MT, Horvath SM
    PMID: 3396569
    Young sedentary adult males of Malay, Indian, and Chinese origin who had established continuous residence in tropical Malaysia and presumed to be naturally acclimatized to heat, were studied to evaluate their physiological responses to a standard heat stress test. The Malay and Indian races have evolved in hot and humid geographical zones, whereas the Chinese originated from a temperate area. Subjects exercised at 50% VO2max alternating 18 minutes walking and 2 min rest during a 2-h exposure to an ambient of 34.9 degrees C dry bulb and 32.1 degrees C wet bulb. Heart rates, core and skin temperatures, sweat rates, and oxygen uptakes were measured during the heat exposure. The subjects of Malay origin exhibited the least circulatory stress of the three ethnic groups. The data obtained on these long-term residents of a hot-wet climate and who were considered acclimatized to this environment were compared to experimental data obtained by other investigators and other ethnic groups.
    Matched MeSH terms: Tropical Climate*
  15. Gnanapragasam A
    Med J Malaya, 1971 Dec;26(2):112-5.
    PMID: 4260855
    Matched MeSH terms: Tropical Climate*
  16. Chin J
    Tubercle, 1964 Jun;45:114-24.
    PMID: 14161910 DOI: 10.1016/S0041-3879(64)80069-6
    A tuberculin skin test survey utilizing standard human PPD and PPD's prepared from some unclassified mycobacteria was conducted in 2,074 school children in Kuala Lumpur, Malaya. Results of the survey are consistent with the hypothesis that 'non-specific" agents are prevalent and acting there. Sensitivity to the Battey PPD was very high in the population tested and there was some evidence of cross sensitivity to human PPD. The public health implications of this are discussed. On the basis of the local findings, a suggestion is made to change the local criterion of a negative tuberculin reaction, for the purpose of giving BCG vaccination, from less than five mm of induration to less than nine mm of induration.
    Matched MeSH terms: Tropical Climate*
  17. Haisman MF
    Br. J. Nutr., 1972 Mar;27(2):375-81.
    PMID: 5015257
    Matched MeSH terms: Tropical Climate*
  18. Pai HH, Lai JL
    Travel Med Infect Dis, 2008 Jul;6(4):201-4.
    PMID: 18571109 DOI: 10.1016/j.tmaid.2008.03.001
    International travel may be associated with the risk of a wide range of infectious diseases. This study was designed to obtain information on the health problems among international travellers from a subtropical region to the neighbouring tropical, subtropical, and temperate regions. Health problems among international travellers from Taiwan to the Philippines, Malaysia, Indonesia, Singapore, Vietnam, Thailand (tropical group), Hong Kong, Macao, China and Japan (non-tropical group) were surveyed through the telephone. Of 649 travellers surveyed, 8.2% had one or more health problems and insect bite (3.4%) and coughing or sore throats (3.2%) were the most important symptoms. The rate of coughing or sore throats was significantly higher among those returned from the non-tropical regions. However, no associations were found between health problems and the demographic factors, travel style or travelling duration of travel.
    Matched MeSH terms: Tropical Climate*
  19. Chave J, Condit R, Muller-Landau HC, Thomas SC, Ashton PS, Bunyavejchewin S, et al.
    PLoS Biol., 2008 Mar 04;6(3):e45.
    PMID: 18318600 DOI: 10.1371/journal.pbio.0060045
    In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and in primary productivity, as well as shifts in plant species composition favouring fast-growing species over slow-growing ones. This pervasive alteration of mature tropical forests was attributed to global environmental change, such as an increase in atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements of over 2 million trees in ten large (16-52 ha each) forest plots on three continents to evaluate the generality of these findings across tropical forests. Aboveground biomass increased at seven of our ten plots, significantly so at four plots, and showed a large decrease at a single plot. Carbon accumulation pooled across sites was significant (+0.24 MgC ha(-1) y(-1), 95% confidence intervals [0.07, 0.39] MgC ha(-1) y(-1)), but lower than reported previously for Amazonia. At three sites for which we had data for multiple census intervals, we found no concerted increase in biomass gain, in conflict with the increased productivity hypothesis. Over all ten plots, the fastest-growing quartile of species gained biomass (+0.33 [0.09, 0.55] % y(-1)) compared with the tree community as a whole (+0.15 % y(-1)); however, this significant trend was due to a single plot. Biomass of slow-growing species increased significantly when calculated over all plots (+0.21 [0.02, 0.37] % y(-1)), and in half of our plots when calculated individually. Our results do not support the hypothesis that fast-growing species are consistently increasing in dominance in tropical tree communities. Instead, they suggest that our plots may be simultaneously recovering from past disturbances and affected by changes in resource availability. More long-term studies are necessary to clarify the contribution of global change to the functioning of tropical forests.
    Matched MeSH terms: Tropical Climate*
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