Displaying publications 181 - 200 of 857 in total

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  1. Diversity partitioning confirms the importance of beta components in tropical rainforest Lepidoptera
    Beck J, Holloway JD, Khen CV, Kitching IJ
    Am Nat, 2012 Sep;180(3):E64-74.
    PMID: 22854086 DOI: 10.1086/666982
    Tropical beta diversity, and particularly that of herbivorous insects in rainforests, is often considered to be enormous, but this notion has recently been challenged. Because tropical beta diversity is highly relevant to our view on biodiversity, it is important to gain more insights and to resolve methodological problems that may lead to contradictions in different studies. We used data on two ecologically distinct moth families from Southeast Asia and analyzed separately the contribution of beta components to overall species richness at three spatial scales. Observed diversity partitions were compared under different types of null models. We found that alpha diversity was lower than expected on the basis of null models, whereas hierarchical beta components were larger than expected. Beta components played a significant role in shaping gamma diversity, and their contribution can be high (multiplicative beta >5). We found a reduction in beta components when comparing primary forests to agricultural sites (cf. "biotic homogenization"), but even in these habitats, beta components were still substantial. Our analyses show that beta components do play an important role in our data on tropical herbivorous insects and that these results are not attributable to lumping different habitats when sampling environmental gradients.
    Matched MeSH terms: Tropical Climate
  2. Childhood pneumonia: a neglected, climate-sensitive disease?
    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*; Climate Change*
  3. Fulltext Future climate effects on suitability for growth of oil palms in Malaysia and Indonesia
    Paterson RR, Kumar L, Taylor S, Lima N
    Sci Rep, 2015;5:14457.
    PMID: 26399638 DOI: 10.1038/srep14457
    The production of palm oil (PO) is highly profitable. The economies of the principal producers, Malaysia and Indonesia, and others, benefit considerably. Climate change (CC) will most likely have an impact on the distribution of oil palms (OP) (Elaeis guineensis). Here we present modelled CC projections with respect to the suitability of growing OP, in Malaysia and Indonesia. A process-oriented niche model of OP was developed using CLIMEX to estimate its potential distribution under current and future climate scenarios. Two Global Climate Models (GCMs), CSIRO-Mk3.0 and MIROC-H, were used to explore the impacts of CC under the A1B and A2 scenarios for 2030, 2070 and 2100. Decreases in climatic suitability for OP in the region were gradual by 2030 but became more pronounced by 2100. These projections imply that OP growth will be affected severely by CC, with obvious implications to the economies of (a) Indonesia and Malaysia and (b) the PO industry, but with potential benefits towards reducing CC. A possible remedial action is to concentrate research on development of new varieties of OP that are less vulnerable to CC.
    Matched MeSH terms: Climate Change
  4. Fulltext Tree traits and canopy closure data from an experiment with 34 planted species native to Sabah, Borneo
    Gustafsson M, Gustafsson L, Alloysius D, Falck J, Yap S, Karlsson A, et al.
    Data Brief, 2016 Mar;6:466-70.
    PMID: 26900591 DOI: 10.1016/j.dib.2015.12.048
    The data presented in this paper is supporting the research article "Life history traits predict the response to increased light among 33 tropical rainforest tree species" [3]. We show basic growth and survival data collected over the 6 years duration of the experiment, as well as data from traits inventories covering 12 tree traits collected prior to and after a canopy reduction treatment in 2013. Further, we also include canopy closure and forest light environment data from measurements with hemispherical photographs before and after the treatment.
    Matched MeSH terms: Tropical Climate
  5. Fulltext Imaging spectroscopy reveals the effects of topography and logging on the leaf chemistry of tropical forest canopy trees
    Swinfield T, Both S, Riutta T, Bongalov B, Elias D, Majalap-Lee N, et al.
    Glob Chang Biol, 2020 02;26(2):989-1002.
    PMID: 31845482 DOI: 10.1111/gcb.14903
    Logging, pervasive across the lowland tropics, affects millions of hectares of forest, yet its influence on nutrient cycling remains poorly understood. One hypothesis is that logging influences phosphorus (P) cycling, because this scarce nutrient is removed in extracted timber and eroded soil, leading to shifts in ecosystem functioning and community composition. However, testing this is challenging because P varies within landscapes as a function of geology, topography and climate. Superimposed upon these trends are compositional changes in logged forests, with species with more acquisitive traits, characterized by higher foliar P concentrations, more dominant. It is difficult to resolve these patterns using traditional field approaches alone. Here, we use airborne light detection and ranging-guided hyperspectral imagery to map foliar nutrient (i.e. P, nitrogen [N]) concentrations, calibrated using field measured traits, over 400 km2 of northeastern Borneo, including a landscape-level disturbance gradient spanning old-growth to repeatedly logged forests. The maps reveal that canopy foliar P and N concentrations decrease with elevation. These relationships were not identified using traditional field measurements of leaf and soil nutrients. After controlling for topography, canopy foliar nutrient concentrations were lower in logged forest than in old-growth areas, reflecting decreased nutrient availability. However, foliar nutrient concentrations and specific leaf area were greatest in relatively short patches in logged areas, reflecting a shift in composition to pioneer species with acquisitive traits. N:P ratio increased in logged forest, suggesting reduced soil P availability through disturbance. Through the first landscape scale assessment of how functional leaf traits change in response to logging, we find that differences from old-growth forest become more pronounced as logged forests increase in stature over time, suggesting exacerbated phosphorus limitation as forests recover.
    Matched MeSH terms: Tropical Climate
  6. Fulltext Utilization of Bracing Arms as Additional Reinforcement in Pultruded Glass Fiber-Reinforced Polymer Composite Cross-Arms: Creep Experimental and Numerical Analyses
    Asyraf MRM, Ishak MR, Sapuan SM, Yidris N
    Polymers (Basel), 2021 Feb 19;13(4).
    PMID: 33669491 DOI: 10.3390/polym13040620
    The application of pultruded glass fiber-reinforced polymer composites (PGFRPCs) as a replacement for conventional wooden cross-arms in transmission towers is relatively new. Although numerous studies have conducted creep tests on coupon-scale PGFRPC cross-arms, none had performed creep analyses on full-scale PGFRPC cross-arms under actual working load conditions. Thus, this work proposed to study the influence of an additional bracing system on the creep responses of PGFRPC cross-arms in a 132 kV transmission tower. The creep behaviors and responses of the main members in current and braced PGFRPC cross-arm designs were compared and evaluated in a transmission tower under actual working conditions. These PGFRPC cross-arms were subjected to actual working loads mimicking the actual weight of electrical cables and insulators for a duration of 1000 h. The cross-arms were installed on a custom test rig in an open area to simulate the actual environment of tropical climate conditions. Further creep analysis was performed by using Findley and Burger models on the basis of experimental data to link instantaneous and extended (transient and viscoelastic) creep strains. The addition of braced arms to the structure reduced the total strain of a cross-arm's main member beams and improved elastic and viscous moduli. The addition of bracing arms improved the structural integrity and stiffness of the cross-arm structure. The findings of this study suggested that the use of a bracing system in cross-arm structures could prolong the structures' service life and subsequently reduce maintenance effort and cost for long-term applications in transmission towers.
    Matched MeSH terms: Tropical Climate
  7. On mental hygiene in the tropics
    Scott GW
    Malayan Medical Journal, 1931;6:88-92.
    Matched MeSH terms: Tropical Climate
  8. Fulltext Comparative field performances between conventional combine and mid-size combine in wetland rice cultivation
    Elsoragaby S, Yahya A, Mahadi MR, Nawi NM, Mairghany M
    Heliyon, 2019 Apr;5(4):e01427.
    PMID: 30984885 DOI: 10.1016/j.heliyon.2019.e01427
    In paddy cultivation, harvesting is the most important operation, which needs suitable machinery. Thus, this study was carried out to compare field performances and energy and environmental effect between the conventional 5 m cutting width NEW HOLLAND CLAYSON 8080, 82 kW@2500 rpm combine harvester running on a total net area of 42.78 ha of plots for two rice (Oryza sativa L.) cultivation seasons and the new mid-size 2.7 m cutting width WORLD STAR WS7.0, 76 kW@2600 rpm combine harvester running on a total net area of 16.95 ha of plots for two rice cultivation seasons. The conventional combine as compared to mid-size combine showed 14.4% greater mean fuel consumptions (21.13 versus 18.46 l/ha), 31.1% greater mean effective field capacity (0.69 versus 0.53 ha/h), 5.23% greater cornering time (turning time) percentage of total time (8.28% versus 3.05%) and 1.41% greater reversing time percentage of total time (7.2% versus 5.79%) but 20.90% lesser mean operational speed (3.24 versus 4.10 km/h), 11.69% lesser effective time percentage of total time (60.0%versus 71.69%h/ha), 10.8% lesser mean field efficiency (64.3% versus 72.1%). In terms of total energy use the conventional combine showed 24.64% greater mean total energy use in the harvesting operation (1445.81 versus 1160.00 MJ/ha), 14.46% greater mean fuel energy (1010.014 versus 882.39 MJ/ha), 56.47% greater mean machinery energy (431.32 versus 275.65 MJ/ha) and 59.25% greater mean human energy (3.48 and 2.18 MJ/ha), this cause 26.12% greater mean total Green House Gas emission (GHG) than the mid-size combine. The results revealed that the mid-size combine is more suitable in conducting the harvest operation in rice field in Malaysia than the conventional combine.
    Matched MeSH terms: Climate
  9. Fulltext Identification of significant climatic risk factors and machine learning models in dengue outbreak prediction
    Yavari Nejad F, Varathan KD
    BMC Med Inform Decis Mak, 2021 04 30;21(1):141.
    PMID: 33931058 DOI: 10.1186/s12911-021-01493-y
    BACKGROUND: Dengue fever is a widespread viral disease and one of the world's major pandemic vector-borne infections, causing serious hazard to humanity. The World Health Organisation (WHO) reported that the incidence of dengue fever has increased dramatically across the world in recent decades. WHO currently estimates an annual incidence of 50-100 million dengue infections worldwide. To date, no tested vaccine or treatment is available to stop or prevent dengue fever. Thus, the importance of predicting dengue outbreaks is significant. The current issue that should be addressed in dengue outbreak prediction is accuracy. A limited number of studies have conducted an in-depth analysis of climate factors in dengue outbreak prediction.

    METHODS: The most important climatic factors that contribute to dengue outbreaks were identified in the current work. Correlation analyses were performed in order to determine these factors and these factors were used as input parameters for machine learning models. Top five machine learning classification models (Bayes network (BN) models, support vector machine (SVM), RBF tree, decision table and naive Bayes) were chosen based on past research. The models were then tested and evaluated on the basis of 4-year data (January 2010 to December 2013) collected in Malaysia.

    RESULTS: This research has two major contributions. A new risk factor, called the TempeRain factor (TRF), was identified and used as an input parameter for the model of dengue outbreak prediction. Moreover, TRF was applied to demonstrate its strong impact on dengue outbreaks. Experimental results showed that the Bayes Network model with the new meteorological risk factor identified in this study increased accuracy to 92.35% for predicting dengue outbreaks.

    CONCLUSIONS: This research explored the factors used in dengue outbreak prediction systems. The major contribution of this study is identifying new significant factors that contribute to dengue outbreak prediction. From the evaluation result, we obtained a significant improvement in the accuracy of a machine learning model for dengue outbreak prediction.

    Matched MeSH terms: Climate
  10. Water quality modeling in sewer networks: Review and future research directions
    Jia Y, Zheng F, Maier HR, Ostfeld A, Creaco E, Savic D, et al.
    Water Res, 2021 Sep 01;202:117419.
    PMID: 34274902 DOI: 10.1016/j.watres.2021.117419
    Urban sewer networks (SNs) are increasingly facing water quality issues as a result of many challenges, such as population growth, urbanization and climate change. A promising way to addressing these issues is by developing and using water quality models. Many of these models have been developed in recent years to facilitate the management of SNs. Given the proliferation of different water quality models and the promise they have shown, it is timely to assess the state-of-the-art in this field, to identify potential challenges and suggest future research directions. In this review, model types, modeled quality parameters, modeling purpose, data availability, type of case studies and model performance evaluation are critically analyzed and discussed based on a review of 110 papers published between 2010 and 2019. The review identified that applications of empirical and kinetic models dominate those of data-driven models for addressing water quality issues. The majority of models are developed for prediction and process understanding using experimental or field sampled data. While many models have been applied to real problems, the corresponding prediction accuracies are overall moderate or, in some cases, low, especially when dealing with larger SNs. The review also identified the most common issues associated with water quality modeling of SNs and based on these proposed several future research directions. These include the identification of appropriate data resolutions for the development of different SN models, the need and opportunity to develop hybrid SN models and the improvement of SN model transferability.
    Matched MeSH terms: Climate Change
  11. Fulltext A description of health complaints and treatment among patients visiting medical relief camps at Aceh and Balakot two months post disastery
    Adlina, S., Narimah, A.H.H., Mazlin, M.M., Nuraliza, A.S., Hakimi, Z.A., Soe, S.A., et al.
    Malaysian Journal of Public Health Medicine, 2006;6(1):51-57.
    MyJurnal
    This study was conducted to determine the patterns of disease and treatment at two disaster sites. Studies prior to this have shown that all natural disasters are unique in that each affected region of the world have different social, economic and health backgrounds. However, similarities exist among the health effects of different disasters which if recognized can ensure that health and emergency medical relief and limited resources are well managed. This study found that although Aceh and Balakot were two totally different areas with reference to locality and climate it was noticed that the patterns of disease two months post disaster are similar the commonest being respiratory conditions followed by musculoskeletal conditions and gastrointestinal conditions. For the treatment patterns it was observed that the two areas prescribed almost similar, types of medicine mainly for gastrointestinal and respiratory systems. However in Aceh, there were more skin treatment and in Balakot there was more usage of musculoskeletal drugs.
    Matched MeSH terms: Climate
  12. Indoor thermal comfort study: A case study at higher institution in East Coast of Malaysia
    Rosli Abu Bakar, Ahmad Rasdan Ismail, Norfadzilah Jusoh, Abdul Mutalib Leman
    Journal of Occupational Safety and Health, 2012;9(3):65-72.
    MyJurnal
    This paper discuss thermal comfort studies of an under air conditioning in hot and humid climate which at one of the higher institution in East Coast of Malaysia. Indoor thermal environment is important as it affects the health and productivity of building occupants. The paper reports on an experimental investigation of indoor thermal comfort characteristics under the control of air conditioning. Firstly, the well known Fanger’s thermal comfort model was simplified for the current experimental investigation. This is followed by reporting the experimental results of indoor thermal comfort characteristics under the control of temperature, with eight different of temperatures which are 22oC to 29oC. Finally, indoor thermal comfort was merely affected by the increment ventilation and outdoor climate. PMV value was higher when near from the window because of the effects of the wall radiations and the metabolic heat.
    Matched MeSH terms: Climate
  13. The training of research workers for tropical countries
    Sandosham AA
    Med J Malaya, 1969 Mar;23(3):189-91.
    PMID: 4240072
    Matched MeSH terms: Tropical Climate
  14. Fulltext Power Reduction with Sleep/Wake on Redundant Data (SWORD) in a Wireless Sensor Network for Energy-Efficient Precision Agriculture
    Jawad HM, Nordin R, Gharghan SK, Jawad AM, Ismail M, Abu-AlShaeer MJ
    Sensors (Basel), 2018 Oct 13;18(10).
    PMID: 30322176 DOI: 10.3390/s18103450
    The use of wireless sensor networks (WSNs) in modern precision agriculture to monitor climate conditions and to provide agriculturalists with a considerable amount of useful information is currently being widely considered. However, WSNs exhibit several limitations when deployed in real-world applications. One of the challenges faced by WSNs is prolonging the life of sensor nodes. This challenge is the primary motivation for this work, in which we aim to further minimize the energy consumption of a wireless agriculture system (WAS), which includes air temperature, air humidity, and soil moisture. Two power reduction schemes are proposed to decrease the power consumption of the sensor and router nodes. First, a sleep/wake scheme based on duty cycling is presented. Second, the sleep/wake scheme is merged with redundant data about soil moisture, thereby resulting in a new algorithm called sleep/wake on redundant data (SWORD). SWORD can minimize the power consumption and data communication of the sensor node. A 12 V/5 W solar cell is embedded into the WAS to sustain its operation. Results show that the power consumption of the sensor and router nodes is minimized and power savings are improved by the sleep/wake scheme. The power consumption of the sensor and router nodes is improved by 99.48% relative to that in traditional operation when the SWORD algorithm is applied. In addition, data communication in the SWORD algorithm is minimized by 86.45% relative to that in the sleep/wake scheme. The comparison results indicate that the proposed algorithms outperform power reduction techniques proposed in other studies. The average current consumptions of the sensor nodes in the sleep/wake scheme and the SWORD algorithm are 0.731 mA and 0.1 mA, respectively.
    Matched MeSH terms: Climate
  15. Dengue fever: a worldwide threat An overview of the infection process, environmental factors for global outbreak, diagnostic platforms, and vaccine developments
    Hosseini S, Oliva-Ramírez J, Vázquez-Villegas P, García AR, Muñoz-Soto RB, Aghamohammadi N, et al.
    Curr Top Med Chem, 2018 Nov 05.
    PMID: 30394209 DOI: 10.2174/1568026618666181105130000
    Current review article focuses on Dengue, which is one of the most fatal infectious illnesses and is considered to be a worldwide threat. The paper covers essential topics including an overview on neglected tropical diseases with specific emphasis on Dengue fever, mosquito's cycle of life and mechanism of infection, adaptive response, and different stages in Dengue immunopathogenesis. The current work is also dedicated to the thorough study of Dengue outbreak across the globe with narrowed study to tropical and subtropical regions. Moreover, this review article demonstrates the correlation between the climate factors and Dengue incidence. Furthermore, we present an overview on the detection strategies of Dengue including the latest developments in commercial and non-commercial platforms. Several attempts in developing effective vaccine to protect individuals from Dengue infection and the stage of clinical trails are gathered in the present work as well. Future directions including bio-control are also discussed in this review article. In an overall view, effective management of Dengue is a multidisciplinary task that requires international involvement from different backgrounds and expertise to address this global concern. This review article briefly portrays some of these connecting areas across the disciplines while many other perspectives remain uncovered.
    Matched MeSH terms: Climate
  16. Fulltext Ambient data analytic on indoor environment monitoring for office buildings in hot and humid climates
    Ngah Nasaruddin A, Tee BT, Musthafah MT, Md Jasman MES
    Data Brief, 2019 Dec;27:104534.
    PMID: 31709283 DOI: 10.1016/j.dib.2019.104534
    The rapid development of open source developmental boards incorporating microcontrollers on printed circuit boards has offered many alternatives in creating feasible, low cost indoor environment monitoring and controlling platforms. Data are collected and stored in predetermined locations throughout a series of communication activities between a network of active sensors and their processing units. However, the issue of data precision and accuracy are of real concern for generating baseline information. Therefore, with that in mind, the purpose of this paper is to accentuate an insightful trend of retrieving indoor environment data (temperature and relative humidity) for an office building in a hot and humid climate condition. The indoor parameters were monitored using a combination of a single board microcontroller with an active sensor with well calibrated thermal microclimate devices. Accordingly, it was found that proactive adjustment can be conducted in order to minimize waste.
    Matched MeSH terms: Climate; Microclimate
  17. Application of loglinear models in estimating wet category in monthly rainfall
    Wahidah Sanusi, Kamarulzaman Ibrahim
    Sains Malaysiana, 2012;41:1345-1353.
    Climate changes have become serious issues that have been widely discussed by researchers. One of the issues concerns with the study in changes of rainfall patterns. Changes in rainfall patterns affect the dryness and wetness conditions of a region. In this study, the three-dimensional loglinear model was used to fit the observed frequencies and to model the expected frequencies of wet class transition on eight rainfall stations in Peninsular Malaysia. The expected frequency values could be employed to determine the odds value of wet classes of each station. Further, the odds values were used to estimate the wet class of the following month if the wet class of the previous month and current month were identified. The wet classification based on SPI index (Standardized Precipitation Index). For station that was analyzed, there was no difference found were between estimated and observed wet classes. It was concluded that the loglinear models can be used to estimate the wetness classes through the estimates of odds values.
    Matched MeSH terms: Climate Change
  18. Posidonomya (Bivalvia) from Northwest Peninsular Malaysia and its significance
    Basir Jasin
    Sains Malaysiana, 2015;44:217-223.
    Posidonomya is common in the Kubang Pasu and Singa Formations in northwest Peninsular Malaysia. It was discovered from the red mudstone layers (redbeds) in many localities in Langkawi Islands, Perlis and Kedah. Previous studies suggested that the age of Posidonomya ranged from Middle Devonian to Carboniferous. Posidonomya beds in Kedah and Perlis are located above the Tournaisian radiolarian chert layers. The age of Posidonomya from Peninsular Malaysia is comparable to those of Europe, Morocco, Turkey and South China which range from Tournaisian to Serpukhovian, Early Carboniferous. The fossil specimens exhibit morphological features closely related to Posidonomya becheri Bronn. Two taxa were identified namely Posidonomya becheri Bronn and Posidonomya cf. kochi (von Koenen). The occurrence of Posidonomya indicates that the age of the lower part of the Kubang Pasu and Singa Formations is Early Carboniferous. Its geographic distribution formed a wide paleobiogeographic province in the Paleo-Tethys. The province was located in the warm tropical-subtropical climatic zone. Therefore, Posidonomya can be a good indicator for warm climate. Its wide distribution and short stratigraphic range make it a good index fossil for the Early Carboniferous.
    Matched MeSH terms: Climate
  19. Projection of storm surge climate extreme over Sunda Shelf based on IPCC SRES A2 scenario
    Wah SH, Halimatun Muhamad, Tangang FT, Liew J
    Sains Malaysiana, 2012;41:1411-1422.
    The historical and future storm surge climate over the South China Sea Sunda Shelf was derived using a barotropic two dimensional model. The atmospheric forcings were obtained from the UKMO regional climate modeling system, PRECIS (Providing Regional Climates for Impacts Studies), forced at the boundary by the ECHAM4 simulation output under the SRES A2 emission experiment. In general, the model simulates historical sea surface elevation characteristics satisfactory although there is a substantial underestimation for the sea level elevation at local scales. The climate change analysis suggests that the storm surge extreme over the Sunda Shelf is expected to increase along the coastal area of the Gulf of Thailand and east coast of Peninsular Malaysia in the future (2071-2100). The projected increment is averagely ~9% over the Sunda Shelf region by the end of the 21st century corresponding to about 5% stronger wind speed as compare to the baseline period of 1961-1990.
    Matched MeSH terms: Climate Change
  20. Grain quality performance and heritability estimation in selected F1 rice genotypes
    Rafii M, Zakiah M, Asfaliza R, Iffah Haifaa M, Latif M, Malek M
    Sains Malaysiana, 2014;43:1-7.
    A total of 17 rice genotypes consisted of 12 F1 progenies and five parental lines were evaluated for performance of grain qualities, yield and yield components and vegetative traits at the Malaysian Agricultural Research and Development Institute (MARDI) Research Station in Seberang Perai, Penang. Except grain length, all other grain quality characters, yield components and vegetative traits varied significantly among the genotypes. Among the studied characters, the highest heritability value was observed in plant height with 99.75% followed by panicle length having 96.90% and grain shape with 56.70% which could be successfully inherited to the next generations. The rest of the traits had low heritability values and ranged from 20.24 to 35.88%. This indicates that the characters are mainly influenced by environmental factors such as geographical effects and climate. However, in the quantitative traits such as grain qualities and yield components, they are usually difficult to inherit to the next generation due to low heritability values. The combinations of Q76 and MR84 had the highest in amylose content while Q76 and MRQ74 had the lowest. Several selected F1 indica rice genotypes from this evaluation are useful for future breeding programme and biotechnological research for the improvement of valuable grain quality traits.
    Matched MeSH terms: Climate
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