Displaying publications 81 - 100 of 445 in total

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  1. Madya Mastika binti Ahmad, Amirah binti Mohd Arif
    MyJurnal
    In this day and age, with the ever-growing population and energy demand, we should take the renewable option route in our energy source. We should also keep in mind that said energy should not cause any lasting environmental damage, one of the perfect example being solar energy. A country that is hot and sunny all year long is the perfect contributor to solar energy, case in point, Malaysia. With that in mind Solar Tree is designed and developed to facilitate consumers who need electric power at any place, anytime, anywhere. The objective of this study is to assess a mini project in the likes of Solar Tree that can generate electricity without harming the environment, despite the weather. Intended specifically to be a mini project, it is understandable that electricity generated is limited, with only up to 500W in total. As a trial, two electronic devices were tested, specifically a mobile phone and a laptop, as both devices are used almost every day. The data collected is then tabulated and analysed. It was concluded the solar tree developed proved efficient in charging both devices and will continue to do so given enough sunlight.
    Matched MeSH terms: Trees
  2. Jumin E, Basaruddin FB, Yusoff YBM, Latif SD, Ahmed AN
    Environ Sci Pollut Res Int, 2021 Jun;28(21):26571-26583.
    PMID: 33484461 DOI: 10.1007/s11356-021-12435-6
    Reliable and accurate prediction model capturing the changes in solar radiation is essential in the power generation and renewable carbon-free energy industry. Malaysia has immense potential to develop such an industry due to its location in the equatorial zone and its climatic characteristics with high solar energy resources. However, solar energy accounts for only 2-4.6% of total energy utilization. Recently, in developed countries, various prediction models based on artificial intelligence (AI) techniques have been applied to predict solar radiation. In this study, one of the most recent AI algorithms, namely, boosted decision tree regression (BDTR) model, was applied to predict the changes in solar radiation based on collected data in Malaysia. The proposed model then compared with other conventional regression algorithms, such as linear regression and neural network. Two different normalization techniques (Gaussian normalizer binning normalizer), splitting size, and different input parameters were investigated to enhance the accuracy of the models. Sensitivity analysis and uncertainty analysis were introduced to validate the accuracy of the proposed model. The results revealed that BDTR outperformed other algorithms with a high level of accuracy. The funding of this study could be used as a reliable tool by engineers to improve the renewable energy sector in Malaysia and provide alternative sustainable energy resources.
    Matched MeSH terms: Decision Trees
  3. Slik JW, Aiba S, Bastian M, Brearley FQ, Cannon CH, Eichhorn KA, et al.
    Proc Natl Acad Sci U S A, 2011 Jul 26;108(30):12343-7.
    PMID: 21746913 DOI: 10.1073/pnas.1103353108
    The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. An additional explanation might be related to the coarse sandy soils of central Sundaland. To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them. We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. For drought tolerance, no such pattern was detected. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. However, we could not confirm the presence of a savanna corridor. This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated.
    Matched MeSH terms: Trees*
  4. Yamada T, Yamada Y, Okuda T, Fletcher C
    Oecologia, 2013 Jul;172(3):713-24.
    PMID: 23183820 DOI: 10.1007/s00442-012-2529-z
    Differences in the density of conspecific tree individuals in response to environmental gradients are well documented for many tree species, but how such density differences are generated and maintained is poorly understood. We examined the segregation of six dipterocarp species among three soil types in the Pasoh tropical forest, Malaysia. We examined how individual performance and population dynamics changed across the soil types using 10-year demographic data to compare tree performance across soil types, and constructed population matrix models to analyze the population dynamics. Species showed only minor changes in mortality and juvenile growth across soil types, although recruitment differed greatly. Clear, interspecific demographic trade-offs between growth and mortality were found in all soil types. The relative trade-offs by a species did not differ substantially among the soil types. Population sizes were projected to remain stable in all soil types for all species with one exception. Our life-table response experiment demonstrated that the population dynamics of a species differed only subtly among soil types. Therefore, species with strong density differences across soil types do not necessarily differ greatly in their population dynamics across the soil types. In contrast, interspecific differences in population dynamics were large. The trade-off between mortality and growth led to a negative correlation between the contributions of mortality and growth to variations in the population growth rate (λ) and thus reduced their net contributions. Recruitment had little impact on the variation in λ. The combination of these factors resulted in little variation in λ among species.
    Matched MeSH terms: Trees/growth & development; Trees/physiology*
  5. Xu H, Detto M, Fang S, Chazdon RL, Li Y, Hau BCH, et al.
    Commun Biol, 2020 06 19;3(1):317.
    PMID: 32561898 DOI: 10.1038/s42003-020-1041-y
    Legumes provide an essential service to ecosystems by capturing nitrogen from the atmosphere and delivering it to the soil, where it may then be available to other plants. However, this facilitation by legumes has not been widely studied in global tropical forests. Demographic data from 11 large forest plots (16-60 ha) ranging from 5.25° S to 29.25° N latitude show that within forests, leguminous trees have a larger effect on neighbor diversity than non-legumes. Where soil nitrogen is high, most legume species have higher neighbor diversity than non-legumes. Where soil nitrogen is low, most legumes have lower neighbor diversity than non-legumes. No facilitation effect on neighbor basal area was observed in either high or low soil N conditions. The legume-soil nitrogen positive feedback that promotes tree diversity has both theoretical implications for understanding species coexistence in diverse forests, and practical implications for the utilization of legumes in forest restoration.
    Matched MeSH terms: Trees*
  6. Miyashita NT, Iwanaga H, Charles S, Diway B, Sabang J, Chong L
    Genes Genet Syst, 2013;88(2):93-103.
    PMID: 23832301
    Bacterial community structure was investigated in five tropical rainforests in Sarawak, Malaysia and one temperate forest in Kyoto, Japan. A hierarchical sampling approach was employed, in which soil samples were collected from five sampling-sites within each forest. Pyrosequencing was performed to analyze a total of 493,790 16S rRNA amplicons. Despite differences in aboveground conditions, the composition of bacterial groups was similar across all sampling-sites and forests, with Acidobacteria, Proteobacteria, Verrucomicrobia, Planctomycetes and Bacteroidetes accounting for 90% of all Phyla detected. At higher taxonomic levels, the same taxa were predominant, although there was significant heterogeneity in relative abundance of specific taxa across sampling-sites within one forest or across different forests. In all forests, the level of bacterial diversity, estimated using the Chao1 index, was on the order of 1,000, suggesting that tropical rainforests did not necessarily have a large soil bacterial diversity. The average number of reads per species (OTUs) per sampling-site was 8.0, and more than 40-50% of species were singletons, indicating that most bacterial species occurred infrequently and that few bacterial species achieved high predominance. Approximately 30% of species were specific to one sampling-site within a forest, and 40-60% of species were uniquely detected in one of the six forests studied here. Only 0.2% of species were detected in all forests, while on average 32.1% of species were detected in all sampling-sites within a forest. The results suggested that bacterial communities adapted to specific micro- and macro-environments, but macro-environmental diversity made a larger contribution to total bacterial diversity in forest soil.
    Matched MeSH terms: Trees/genetics*; Trees/microbiology
  7. Hwang WH, Shen TJ
    Biometrics, 2010 Dec;66(4):1052-60.
    PMID: 20002401 DOI: 10.1111/j.1541-0420.2009.01371.x
    Many well-known methods are available for estimating the number of species in a forest community. However, most existing methods result in considerable negative bias in applications, where field surveys typically represent only a small fraction of sampled communities. This article develops a new method based on sampling with replacement to estimate species richness via the generalized jackknife procedure. The proposed estimator yields small bias and reasonably accurate interval estimation even with small samples. The performance of the proposed estimator is compared with several typical estimators via simulation study using two complete census datasets from Panama and Malaysia.
    Matched MeSH terms: Trees*
  8. Wills C, Condit R
    Proc Biol Sci, 1999 Jul 22;266(1427):1445-52.
    PMID: 10457617
    Quadrat-based analysis of two rainforest plots of area 50 ha, one in Panama (Barro Colorado Island, BCI) and the other in Malaysia (Pasoh), shows that in both plots recruitment is in general negatively correlated with both numbers and biomass of adult trees of the same species in the same quadrat. At BCI, this effect is not significantly influenced by treefall gaps. In both plots, recruitment of individual species is negatively correlated with the numbers of trees of all species in the quadrats, but not with overall biomass. These observations suggest, but do not prove, widespread frequency-dependent effects produced by pathogens and seed-predators that act most effectively in quadrats crowded with trees. Within-species correlations of mortality with numbers or biomass are not found in either plot, indicating that most frequency-dependent mortality takes place before the trees reach 1 cm in diameter. Stochastic effects caused by BCI's more rapid tree turnover may contribute to a larger variance in diversity from quadrat to quadrat at BCI, although they are not sufficient to explain why BCI has fewer than half as many tree species as Pasoh. Finally, in both plots quadrats with low diversity show a significant increase in diversity over time, and this increase is stronger at BCI. This process, like the frequency-dependence, will tend to maintain diversity over time. In general, these non-random forces that should lead to the maintenance of diversity are slightly stronger at BCI, even though the BCI plot is less diverse than the Pasoh plot.
    Matched MeSH terms: Trees/physiology*
  9. Carrasco LR
    Science, 2013 Jul 26;341(6144):342-3.
    PMID: 23888020 DOI: 10.1126/science.341.6144.342-b
    Matched MeSH terms: Trees
  10. Kai Z, Woan TS, Jie L, Goodale E, Kitajima K, Bagchi R, et al.
    PLoS One, 2014;9(1):e86598.
    PMID: 24466163 DOI: 10.1371/journal.pone.0086598
    The value of local ecological knowledge (LEK) to conservation is increasingly recognised, but LEK is being rapidly lost as indigenous livelihoods change. Biodiversity loss is also a driver of the loss of LEK, but quantitative study is lacking. In our study landscape in SW China, a large proportion of species have been extirpated. Hence, we were interested to understand whether species extirpation might have led to an erosion of LEK and the implications this might have for conservation. So we investigated peoples' ability to name a selection of birds and mammals in their local language from pictures. Age was correlated to frequency of forest visits as a teenager and is likely to be closely correlated to other known drivers of the loss of LEK, such as declining forest dependence. We found men were better at identifying birds overall and that older people were better able to identify birds to the species as compared to group levels (approximately equivalent to genus). The effect of age was also stronger among women. However, after controlling for these factors, species abundance was by far the most important parameter in determining peoples' ability to name birds. People were unable to name any locally extirpated birds at the species level. However, contrary to expectations, people were better able to identify extirpated mammals at the species level than extant ones. However, extirpated mammals tend to be more charismatic species and several respondents indicated they were only familiar with them through TV documentaries. Younger people today cannot experience the sights and sounds of forest animals that their parents grew up with and, consequently, knowledge of these species is passing from cultural memory. We suggest that engaging older members of the community and linking the preservation of LEK to biodiversity conservation may help generate support for conservation.
    Matched MeSH terms: Trees*
  11. Md-Zain BM, Abdul-Aziz A, Aifat NR, Mohd-Yusof NS, Zulkifli NA, Japning JRR, et al.
    Data Brief, 2019 Jun;24:103532.
    PMID: 31193484 DOI: 10.1016/j.dib.2018.11.117
    This article contains data of the sequence variation in the mitochondrial DNA D-loop region of the Malayan gaur (Bos gaurus hubbacki), locally known as the seladang, from two captive centers. Thirty fecal samples of Malayan gaur were collected from Jenderak Selatan Wildlife Conservation Center (Pahang) and the Sungkai Wildlife Reserve (Perak) for DNA extraction and amplification with polymerase chain reactions. DNA sequences were then analyzed using neighbor joining (NJ) and maximum parsimony (MP) methods. Based on the 652 base pairs obtained, we found seven variable characters with a value of 1%. The genetic distance between the two captive centers was 0.001. Haplotype analyses detected only four haplotypes between these two captive centers. Both NJ and MP trees demonstrate that all individuals in the Jenderak and Sungkai captive centers are in the same clade. Genetic variation of the Malayan gaur in these centers is considered low, possibly because individuals share the same common parent. This sequence variation data are of paramount importance for designing a proper breeding and management program of the Malayan gaur in the future.
    Matched MeSH terms: Trees
  12. Syahrul Affandi Saidi, Syarifah Idrus Sofia Syed Mohd Yamin, Mohd Sharizan Md Sarip, Wan Azani Mustafa
    MyJurnal
    In Malaysia, it is estimated that almost 80 percent of the world's population today used palm oil in their daily lives. Malaysia is the second country exporting palm oil, about 39 percent of world palm oil output. Besides that, Malaysia also recorded about 44 per cent of world exports, making the palm industry very important for countries other than rubber and cocoa. However, to keep the palm industry running smoothly and constantly, there are many challenges to face. One is to maintain soil fertility because the soil can affect the growth of oil palm trees. With the use of this system, it will show the condition of soil behaviour to the farmer about the treatment given. Arduino board is used in this project which it is programmed to calculate and display the level of soil condition by using temperature sensor and soil moisture sensors as an input. This sensor will detect the level of soil moisture and temperature and it is easier for farmers to monitor the soil conditions. Controlled soil conditions can improve the soil's ability to maintain the fertility of palm trees and help plant growth suit to the weather and local climate.
    Matched MeSH terms: Trees
  13. Magrach A, Senior RA, Rogers A, Nurdin D, Benedick S, Laurance WF, et al.
    Proc Biol Sci, 2016 Mar 16;283(1826):20153008.
    PMID: 26936241 DOI: 10.1098/rspb.2015.3008
    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'.
    Matched MeSH terms: Trees/physiology*
  14. Seidler TG, Plotkin JB
    PLoS Biol, 2006 Oct;4(11):e344.
    PMID: 17048988
    Theories of tropical tree diversity emphasize dispersal limitation as a potential mechanism for separating species in space and reducing competitive exclusion. We compared the dispersal morphologies, fruit sizes, and spatial distributions of 561 tree species within a fully mapped, 50-hectare plot of primary tropical forest in peninsular Malaysia. We demonstrate here that the extent and scale of conspecific spatial aggregation is correlated with the mode of seed dispersal. This relationship holds for saplings as well as for mature trees. Phylogenetically independent contrasts confirm that the relationship between dispersal and spatial pattern is significant even after controlling for common ancestry among species. We found the same qualitative results for a 50-hectare tropical forest plot in Panama. Our results provide broad empirical evidence for the importance of dispersal mode in establishing the long-term community structure of tropical forests.
    Matched MeSH terms: Trees/physiology*
  15. Othman M, Genapathy S, Liew PS, Ch'ng QT, Loh HS, Khoo TJ, et al.
    Nat Prod Res, 2011 Nov;25(19):1857-64.
    PMID: 21838540 DOI: 10.1080/14786419.2010.537274
    The world's rainforests hold untold potential for drug discovery. Rainforest plants are thought to contain evolved defensive active metabolites of greater diversity compared to plants from temperate regions. In recent years, the interest and overall output from pharmaceutical companies on novel antibacterial agents has diminished at a time when there is a critical need for them to fight the threat of resistance. In this study, we have investigated the antimicrobial properties of 21 flowering plants from 16 different families against six bacterial strains consisting of two Gram negative and four Gram positive. Using the pour plate disc diffusion technique, almost all extracts from these plants were found to be active against some of the bacterial strains tested. The most interesting and active plants with broad spectrum activities include Duabanga grandiflora, Acalypha wilkesiana and Pseuduvaria macrophylla where the minimum inhibitory concentration, minimum bactericidal concentration and phytochemical analysis were carried out. This is the first report describing the antimicrobial and phytochemical properties of D. grandiflora and P. macrophylla. Our findings support the utilisation of higher plant species in the search for new antimicrobial molecules to combat new emerging infective diseases and the problem of drug resistant pathogens.
    Matched MeSH terms: Trees*
  16. Sambanthamurthi R, Rajanaidu N, Hasnah Parman S
    Biochem Soc Trans, 2000 Dec;28(6):769-70.
    PMID: 11171201
    The oil palm mesocarp contains an endogenous lipase which is strongly activated at low temperature. Lipase activity is thus very conveniently assayed by prior exposure of the fruits to low temperature. More than 100 oil palm samples from the germplasm collection of the Palm Oil Research Institute of Malaysia (now known as the Malaysian Palm Oil Board) were screened for non-esterified fatty acid activity using both the low-temperature activation assay and a radioactivity assay. The results showed good correlation between assay procedures. The different samples had a very wide range of lipase activity. Elaeis oleifera samples had significantly lower lipase activity compared with E. guineensis (var. tenera) samples. Even within E. guineensis (var. tenera), there was a wide range of activity. The results confirmed that lipase activity is genotype-dependent. Selection for lipase genotypes is thus possible and this will have obvious commercial value.
    Matched MeSH terms: Trees/enzymology
  17. Ahmad A, Rafatullah M, Sulaiman O, Ibrahim MH, Hashim R
    J Hazard Mater, 2009 Oct 15;170(1):357-65.
    PMID: 19464117 DOI: 10.1016/j.jhazmat.2009.04.087
    Meranti (Philippine mahogany) sawdust, an inexpensive material, showed strong scavenging behaviour through adsorption for the removal of methylene blue (MB) from aqueous solution. Batch studies were performed to evaluate and optimize the effects of various parameters such as contact time, pH, initial dye concentrations and adsorbent dosage. Langmuir, Freundlich and Temkin isotherms were used to analyze the equilibrium data at different temperatures. The experimental data fitted well with the Langmuir adsorption isotherm, indicating thereby the mono layer adsorption of the dye. The monolayer sorption capacity of meranti sawdust for MB was found to be 120.48, 117.64, 149.25 and 158.73 mg/g at 30, 40, 50 and 60 degrees C, respectively. Thermodynamic calculations showed that the MB adsorption process is endothermic and spontaneous in nature. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model. The results indicated that the meranti sawdust could be an alternative material in place of more costly adsorbents used for dye removal.
    Matched MeSH terms: Trees
  18. Azmy MM, Hashim M, Numata S, Hosaka T, Noor NS, Fletcher C
    Sci Rep, 2016 08 26;6:32329.
    PMID: 27561887 DOI: 10.1038/srep32329
    General flowering (GF) is a unique phenomenon wherein, at irregular intervals, taxonomically diverse trees in Southeast Asian dipterocarp forests synchronize their reproduction at the community level. Triggers of GF, including drought and low minimum temperatures a few months previously has been limitedly observed across large regional scales due to lack of meteorological stations. Here, we aim to identify the climatic conditions that trigger large-scale GF in Peninsular Malaysia using satellite sensors, Tropical Rainfall Measuring Mission (TRMM) and Moderate Resolution Imaging Spectroradiometer (MODIS), to evaluate the climatic conditions of focal forests. We observed antecedent drought, low temperature and high photosynthetic radiation conditions before large-scale GF events, suggesting that large-scale GF events could be triggered by these factors. In contrast, we found higher-magnitude GF in forests where lower precipitation preceded large-scale GF events. GF magnitude was also negatively influenced by land surface temperature (LST) for a large-scale GF event. Therefore, we suggest that spatial extent of drought may be related to that of GF forests, and that the spatial pattern of LST may be related to that of GF occurrence. With significant new findings and other results that were consistent with previous research we clarified complicated environmental correlates with the GF phenomenon.
    Matched MeSH terms: Trees
  19. Marryanna Lion, Siti-Aisah Shamsuddin, Wan Mohd Shukri Wan Ahmad
    Sains Malaysiana, 2017;46:359-363.
    Sap flow pattern of Tectona grandis planted at lowland forest assessed. This study aimed to determine the sap movement
    of two different diameter sizes T. grandis. Two sizes selected were 16 and 38 cm in diameter at breast height (dbh). Sap
    flow meter (SFM) used to assess the sap velocity rates at the interval of 30 min within 24 h for 15 days. Diurnal sap flow
    of T. grandis shows that mean velocity is high during day time compared night time. Small diameter has high sap flow
    compared to that of bigger diameter. A flow rates was high at the inner layer and less at outer layer for smaller tree. The
    variation was vice versa when the tree was getting bigger. Variations in sap flow of T. grandis characterized by several
    environmental factors. It was found that size contribute in the differed sap flow of T. grandis.
    Matched MeSH terms: Trees
  20. Arshad S, Ahmad M, Saboor A, Ibrahim FH, Mustafa MRU, Zafar M, et al.
    Microsc Res Tech, 2019 Feb;82(2):92-100.
    PMID: 30511479 DOI: 10.1002/jemt.23106
    Climate change is the most realistic theory of this era. Sudden and drastic changes are happening on the earth and the survival of mankind is becoming questionable in the future. The plants play the key role in controlling the climate change. The study emphasizes on role of trees in the cop up or damaging the climate of this earth, whether they are medicinal trees or economically important trees. Due to the overgrazing and intense deforestation the climate is being affected hazardously. The global warming phenomenon is occurring due to the less availability of trees and more carbon dioxide in the atmosphere. In total 20 plants were collected from across the Pakistan on the basis of their abundance and their key roles. Out of which seeds of eight plants were scanned through scanning electron microscope for correct authentication and importance of these medicinally important trees in mitigating the climate change. RESEARCH HIGHLIGHTS: The role of forest sector in the climate's change mitigation. Medicinally and economically important tree species across Pakistan. By using SEM, Ultra seed sculpturing features as an authentication tool. To formulate some policies to stop or control deforestation.
    Matched MeSH terms: Trees/classification*; Trees/growth & development*
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