Lignocellulose from oil palm empty fruit bunch fiber (EFB) has been identified as another source for conversion into renewable energy or value added products. Cellulose, hemicellulose and lignin were extracted from EFB via a new treatment method using aqueous glycerol as a potential delignification agent. The aim of this study was to investigate the effect of treatment time and EFB to solvent ratio on the analytical compositions of EFB with or without further treatment with aqueous glycerol. The cooking time was varied at 3, 5 and 7 h with temperature fixed at 85°C. Three types of EFB were used; untreated fiber (UT-EFB), pretreated fiber with 5% (w/v) sodium hydroxide solution (N-EFB) and pretreated fiber with 5% (w/v) acetic acid solution (A-EFB). The analyses carried out were determination of extractives content, Klason Lignin, α-cellulose, hemicelluloses, holocellulose and ash content based on dry weight of the EFB. An increase in the glycerolysis time resulted in reduced content of Klason lignin and extractives but high percentages of holocellulose and α-cellulose for all EFB samples. Treatment of EFB with alkaline solution prior to glycerolysis resulted in reduction in cellulose content compared with holocellulose.
A phytochemical investigation on the acetone extract of the stem bark of Shorea faguetiana was conducted. The isolation of the chemical compounds was carried out by different chromatographic techniques and their structures were elucidated by spectroscopic methods including UV, IR, NMR and MS, and also by comparison with the literature. Five oligostilbenes were isolated and identified as (-)-ε-viniferin, (-)-α-viniferin, (-)-laevifonol, (-)-ampelopsin E and (-)-hopeaphenol.
The effects of various concentrations of honey and sucrose on the longevity and fecundity of Apanteles metesae (Nixon), an endoparasitoid of oil palm bagworm, Metisa plana (Walker) (Lepidoptera: Psychidae) were studied in the laboratory. Our results showed that there were a significant difference (p<0.05) in the longevity of A. metesae fed on various concentrations of honey solutions. Longevity of A. metesae was significantly longer when fed on 50% honey than on pure honey. Nonetheless, longevity of A. metesae females when fed on 50% honey was relatively longer than other honey concentrations. The parasitoid lived significantly longer when fed on 20% sucrose than fed on 50% sucrose and distilled water. However, the parasitoid fed on 50% honey had a longevity that was statistically similar to 20% sucrose and 50% sucrose. Fecundity of A. metesae differed significantly (p<0.05) when fed on 50% honey, 20% sucrose and 50% sucrose. The highest and lowest fecundity was when the parasitoids fed on 20% sucrose and distilled water, respectively. Overall, the result showed that 20% sucrose was a more suitable diet for A. metesae females as compared with other diets.
Gynura procumbens, locally known in Malaysia as Sambung Nyawa is a medicinal plant belonging to the Asteraceae (Compositae) family. G. procumbens have been traditionally used by the local and indigenous populations to treat an array of ailments ranging from skin conditions and fever to kidney disease, inflammation and diabetes. In the present investigation, aqueous and ethanol extracts of G. procumbens were evaluated for anti-plasmodial activities in vitro and in vivo. Survival of two chloroquine-sensitive strains of malarial parasites; rodent Plasmodium berghei NK65 and human Plasmodium falciparum 3D7 was determined following incubations in vitro with extracts. Based on parasite lactate dehydrogenase (pLDH) assay, both extracts were shown to inhibit parasite proliferation to varying degrees. The aqueous extract was more potent than the ethanol extract at suppressing growth of both parasites in vitro; each displaying IC50 values of 12.40 ± 6.02 and 14.38 ± 7.53 μg/mL towards P. berghei NK65; and 25.69 ± 4.34 and 42.23 ± 7.19 μg/mL towards P. falciparum 3D7, respectively. The aqueous extract was found to be selective for P. falciparum (Selectivity Index 64.30). Four-day suppressive tests in ICR mice showed dose-dependent chemo-suppressive activities of both plant extracts tested towards P. berghei NK65. Daily intra-peritoneal injections of the aqueous extract of G. procumbens at 25, 50 or 100 mg/kg for four consecutive days showed chemo-suppression of 50.42 ± 3.17, 65.95 ± 5.48 and 81.92 ± 3.07%, respectively. At the same dosages, the ethanol plant extract resulted in 44.97 ± 3.44, 55.21 ± 3.87 and 64.44 ± 4.05% chemo-suppression respectively. At 250 mg/kg/day, only the aqueous plant extract gave >90% chemo-suppression (93.06 ± 5.46%). Treatment of P. berghei-infected mice with extracts improved the median survival time compared to non-treated infected mice. This represents the first report showing anti-plasmodial activity of G. procumbens.
Mysis, post larvae and adult specimens of Penaeus monodon were sequenced for Cyctochrome C Oxidase subunit I (COI) gene (DNA barcode) to check the efficiency of DNA barcode in delineating species irrespective of its different life stages. COI gene sequences of different life stages of P. monodon were subjected to pair-wise distance analysis, nucleotide sequence diversity estimation, phylogenetic and BOLD analysis. The pair-wise distance estimation revealed that intra-specific variations within the barcode sequences of P. monodon were low when compared with other species of genus Penaeus spp. The average pair-wise distance within the sequences of different stages of P. monodon was two times lesser than the pair-wise distance of the out-group used. The nucleotide diversity within the barcodes were low (π = 0.324). The constructed phylogram clearly showed that the DNA barcoding using partial COI gene would provide an accurate delineation of species irrespective of their different life stages. The BOLD analysis accurately identified all sequences as belonging to P. monodon.
This study aimed to document the fish diversity and water quality at Semariang mangrove area, Kuching, Sarawak, which is located at the eastern part of Kuching Wetland National Park. Field samplings were carried out in 2009 during the construction of the flood mitigation channel at the eastern part of the park. A total of 21 families represented by 37 species of fish were caught from the area. The six dominant families in terms of the number of individuals caught were Mugilidae (16%), Leiognathidae (16%), Ambassidae (11%), Ariidae (9%), Lutjanidae (8%) and Plotosidae (6%). In terms of the percentage of six dominant genera based on the number of individuals caught, 16% was represented by Valamugil, 11% by Ambassis, 10% by Gazza, 9% by Arius, 8% by Lutjanus and 6% by Plotosus. The values of diversity and richness indices were lower at stations located close to the flood mitigation channel. Similarly, the concentrations of dissolved oxygen were lower and total suspended solids were significantly higher at stations close to the channel and sand mining area. Therefore, fish fauna and water quality at Semariang mangrove area were affected during the construction of the flood mitigation channel.
Harmful algal blooms (HABs) events have been increasingly reported in the country, not only of the frequency and severity of the events, but also involved more species than previously known. In this paper, a decadal review of HABs events in Malaysia is summarized. Bloom events caused by harmful dinoflagellate species including the shellfish poisoning events were highlighted. Paralytic shellfish poisoning (PSP) is no longer restricted to Sabah coasts and Pyrodnium bahamense. Bloom of Alexandrium minutum was reported for the first time in the Peninsula with six persons hospitalized including one casualty after consuming the contaminated benthic clams. Algal blooms that are associated with incidence of massive fish kills have been reported from both east and west coasts of the Peninsula in conjunction to finfish mariculture loses. The culprits of these bloom events have been identified as the dinoflagellates, Cochlodinium polykrikoides, Neoceratium furca, Prorocentrum minimum, Noctiluca scintillans and a raphidophyte, Chatonella ovata. In this paper, some of these HABs species were characterized morphologically and genetically, including their toxicity. Therefore, with the increase of coastal utilization and eutrophication, prevention, management and mitigation strategies, such as site selection, moving pens, clay spraying should be adopted to minimize the impact of these natural events.
Relationship between understory plant diversity and anthropogenic disturbances in urban forests of Wuhan City, Central China, was analyzed by diversity analysis and detrended canonical correspondence analysis (DCCA). The results showed that: understory species diversity was higher in suburban area than in urban area. From forest center to edge, species diversity of Luojia hill, Shizi hill and Maan hill forests gradually increased, however, that of Hong hill gradually decreased. Anthropogenic disturbances gradient resulted from visitors flowrate, shrub coverage, aspect and adjacent land types had significant effects on species diversity of shrub and herb layers in urban forests. High anthropogenic disturbances might increase similar non-native herb species in urban area and low disturbances might promote co-existence of wood species in suburban area. Further analysis on types of anthropogenic disturbances and plant functional groups in urban-suburban gradient should be taken into a consideration.
This paper proposed an efficient modification of homotopy perturbation transform method (HPTM), namely modified homotopy perturbation transform method (MHPTM) for the solution of third order boundary layer equation on semi-infinite domain. The technique was based on the application of Laplace transform to boundary layers in fluid mechanics. The nonlinear terms can be easily handled by the use of He’s polynomials. The Pade´ approximants, that often show superior performance over series approximations, were effectively used in the analysis to capture the essential behavior of the boundary layer equation on infinity. We then conduct a comparative study between the MHPTM and the existing results with the help of third order boundary layer equation. The results obtained indicated that the MHPTM was effective and promising.
A Poisson model typically is assumed for count data, but when there are so many zeroes in the response variable, because of overdispersion, a negative binomial regression is suggested as a count regression instead of Poisson regression. In this paper, a zero-inflated negative binomial regression model with right truncation count data was developed. In this model, we considered a response variable and one or more than one explanatory variables. The estimation of regression
parameters using the maximum likelihood method was discussed and the goodness-of-fit for the regression model was examined. We studied the effects of truncation in terms of parameters estimation, their standard errors and the goodnessof-fit statistics via real data. The results showed a better fit by using a truncated zero-inflated negative binomial regression model when the response variable has many zeros and it was right truncated.
We give details about how a surface plasmons with phase singularities can be produced when a Bessel beam light is totally reflected internally at the planar surface of a dielectric on which an infinitesimally thin film has been deposited. The characteristic property of such a light is the exponential decay with distance in a vacuum which can basically provide a two-dimensional surface plasmons with phase singularities with attractive enhancements. Such a phenomenon is governable by altering the incident angle and the order of the Bessel beam.
The objective of this study was to develop a method for the determination of diuron (3-(3,4-dichlorophenyl)-1,1-dimethyl urea) residue in crude palm oil (CPO) and crude palm kernel oil (CPKO) matrices. The method involves the extraction of the herbicide from the oil matrix using low temperature precipitation and solid phase extraction techniques, detected by high performance liquid chromatography-ultra violet (HPLC-UV). The HPLC separation was carried out on an Ascentis
TMRP-Amide column and elution with acetonitrile (solvent A) and water-methanol (2:1, v/v) (solvent B) as a suitable solvent system, at ratio of 4:6 (v/v). The optimum volume of acetonitrile for the extraction of diuron was 30 mL and 4 mL was obtained as the optimum volume of the solvent for elution analyte through the SPE cartridge. A linear correlation was obtained for the concentration of diuron from 0.05–1.0 µg mL-1 with a correlation coefficient of 0.99. The recovery of diuron from CPO was 83.2–101.4% with a relative standard deviation of 1.4–9.9% and 79.4–87.9% with relative standard deviation of 0.9–5.6% for CPKO. The method detection limit and limit of quantification obtained were 0.018 µg g-1 and 0.058 µg g-1, respectively. The method was used to determine diuron residues in palm oil from different refineries situated at different locations throughout Malaysia.
Vermicomposting for 140 days by using Lumbricus rubellus was conducted after 21 days of natural pre-composting. Five treatments in different ratio of goat manure: spent mushroom substrate were prepared as feed materials with four replicates for each treatment namely; 20:80 (TA), 40:60 (TB), 50:50 (TC), 60:40 (TD) and 80:20 (TE). As for control, each treatment without earthworm was prepared. On the basis of nutrient elements, goat manure and spent mushroom substrate can be decomposed through both methods of vermicomposting and natural composting. Findings of this study indicated that the higher usage of goat manure with longer duration resulted in the production of improved organic fertilizer.
Phytochemical compounds, antioxidant and antibacterial activities of selected ethanolic aromatic Malaysian herbal extracts namely Persicaria hydropiper, Citrus hystrix, Murraya koenigii, Etlingera elatior, Cymbopogon citratus and Kaempferia galanga were screened and determined. Antioxidant activities were analysed using Ferric Reducing Antioxidant Power (FRAP), β-carotene bleaching and Oxygen Radical Absorbance Capacity (ORAC) assays. Disc diffusion assay was used to determine antibacterial activity against six bacteria strains. Alkaloids, flavonoids, saponins, tannins, terpenoids and steroids were detected in the herb extracts. P. hydropiper extract had the highest antioxidant activities in FRAP and ORAC assays in which 1676.67 mM TE/g EW and 11.20 mmol TE/g EW were obtained, respectively. However, M. koenigii extract showed 61.8% inhibition in β-carotene bleaching assay among samples but lower than BHA/BHT standard. M. koenigii extract showed the most effective antibacterial activity against three Gram-positive bacteria. Aromatic Malaysian herbs such as P. hydropiper and M. koenigii were found to exhibit high antioxidant and antibacterial activities.
Sapium baccatum is usually used as a timber in Malaysia. Its medicinal values are not well known and very little research has been conducted concerning the plant. Consequently, this study was conducted to observe toxicity effects of hexane extract of stem bark of S. baccatum. The toxicity effects were assessed through observation of physiological changes of the rats as well as through gross and histological examinations of its livers. The doses for the treated groups were given intraperitoneally for T2, T3 and T4 group which were given 100, 250 and 500 mg/kg, respectively. Meanwhile, control group (T1) was administered with 80% PEG 200 only. The observation period was 14 days. If the rat died, it was dissected and the liver was removed and examined. Some physiological effects observed include ataxia and hind-legs paralysis. The gross observations of the livers, growth of abnormal spots and connective tissues attachment to lobes of the livers were observed. The experiment was followed byhistopathological observation, which indicated the presence of abnormal hepatocytes with a distorted shape and undefined cell linings for T2 group. Results also indicated an increase in the distortion of hepatocytes, presence of massive cytoplasm and necrosis of hepatocytes for T3 and T4 groups. The results suggest that non polar extract of the stem bark of S. baccatum may promote toxic effects to the animals.
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.
Statistical modeling of extreme rainfall is essential since the results can often facilitate civil engineers and planners to estimate the ability of building structures to survive under the utmost extreme conditions. Data comprising of annual maximum series (AMS) of extreme rainfall in Alor Setar were fitted to Generalized Extreme Value (GEV) distribution using method of maximum likelihood (ML) and Bayesian Markov Chain Monte Carlo (MCMC) simulations. The weakness of ML method in handling small sample is hoped to be tackled by means of Bayesian MCMC simulations in this study. In order to obtain the posterior densities, non-informative and independent priors were employed. Performances of parameter estimations were verified by conducting several goodness-of-fit tests. The results showed that Bayesian MCMC method was slightly better than ML method in estimating GEV parameters.
MeSH terms: Bayes Theorem; Markov Chains; Monte Carlo Method; Probability; Models, Statistical
This paper aims to estimate the Generalized Pareto Distribution (GPD) parameters and predicts the T-year return levels of extreme rainfall events using the Partial Duration Series (PDS) method based on the hourly rainfall data of five stations in Peninsular Malaysia. In particular, the GPD parameters are estimated using five methods namely the method of Moments (MOM), the probability weighted moments (PWM), the L-moments (LMOM), the Trimmed L-moments (TLMOM) and the Maximum Likelihood (ML) and the performance of the T-year return level of each estimation method is analyzed based on the RMSE measure obtained from Monte Carlo simulation. In addition, we suggest the weighted average model, a model which assigns the inverse variance of several methods as weights, to estimate the T-year return level. This paper contributes to the hydrological literatures in terms of three main elements. Firstly, we suggest the use
of hourly rainfall data as an alternative to provide a more detailed and valuable information for the analysis of extreme rainfall events. Secondly, this study applies five methods of parametric approach for estimating the GPD parameters and predicting the T-year return level. Finally, in this study we propose the weighted average model, a model that assigns the inverse variance of several methods as weights, for the estimation of the T-year return level.
MeSH terms: Malaysia; Monte Carlo Method; Polymethacrylic Acids; Probability; Hydrology
Rainfalls data have been broadly used in researches including in hydrological and meteorological areas. Two common ways in extracting observations from hourly rainfalls data are the window-based analysis (WBA) and storm-event analysis (SEA) approach. However, the differences in the qualitative and quantitative properties of both methods are still vaguely discussed. The aim of studying these dissimilarities is to understand the effects of each approach in modelling and analysis. The qualitative difference is due to the way the two analyses define the accumulated rainfalls for observations which are referred to as rainfall and storm depths, respectively. The repetitiveness of rainfall depths provide nested structure while the storm depths are considered independent. The quantitative comparisons include their statistical and scaling properties that are linked by the self-similarity concept from simple scaling characteristics. If self-similarity concept
holds, then the rainfall or storm depths follow simple scaling and the analysis would be simplified. The rainfall depths showed clearer simple scaling characteristics compared to the storm depths. Though the storm depths do not yield self-similarity for a large range of storm duration but the characteristics of simple scaling can be observed for a reduced range of the considered duration. In general, the context of the research and the region of the time interval and duration will be an important aspects to consider in choosing which method is best to use for analyzing the data.
Long-memory is often observed in time series data. The existence of long-memory in a data set implies that the successive data points are strongly correlated i.e. they remain persistent for quite some time. A commonly used approach in modellingthe time series data such as the Box and Jenkins models are no longer appropriate since the assumption of stationary is not satisfied. Thus, the scaling analysis is particularly suitable to be used for identifying the existence of long-memory as well as the extent of persistent data. In this study, an analysis was carried out on the observed daily mean per hour of ozone concentration that were available at six monitoring stations located in the urban areas of Peninsular Malaysia from 1998 to 2006. In order to investigate the existence of long-memory, a preliminary analysis was done based on plots of autocorrelation function (ACF) of the observed data. Scaling analysis involving five methods which included rescaled range, rescaled variance, dispersional, linear and bridge detrending techniques of scaled windowed variance were applied to estimate the hurst coefficient (H) at each station. The results revealed that the ACF plots indicated a slow decay as the number lag increased. Based on the scaling analysis, the estimated H values lay within 0.7 and 0.9, indicating the existence of long-memory in the ozone time series data. In addition, it was also found that the data were persistent for the period of up to 150 days.
MeSH terms: Malaysia; Memory; Ozone; Personal Satisfaction