The behaviour and aggregation of fish in an artificial reef area in Tioman Island, Malaysia, was observed using underwater videography under a combination of shooting conditions. The camera distance and direction relative to the neighboring artificial reef module was varied, and comparisons of images with a color filter were made. A distance of 260 cm at a diagonal shooting angle provided a suitable observation of the reef fish around the reef module, and a red color filter provided a truer color replication in morning observations while better images were obtained without the color filter in afternoon light environments. Four criteria were considered to assess the artificial reef effectiveness: total abundance, appearance rate, residence time and feeding frequency. A total of 824 individuals were observed during the study. Mean residence times were shorter for schooling fishes such as Caesio caerulaurea and Liza subviridis, and longer for solitary swimmers like Cephalopholis boenak and Scolopsis bilineatus. Feeding frequency was lower for schooling fishes. A significant correlation was obtained between the feeding frequency and residence time for the high feeding frequency fishes (r = 0.89; p<0.05). The effectiveness of the artificial reef was suggested to be significant in solitary swimmers but less so for schooling fishes.
In this paper, four types of circular probability distribution were used to evaluate which circular probability distribution gives the best fitting for southwesterly Malaysian wind direction data, namely circular uniform distribution, von Mises distribution, wrapped-normal distribution and wrapped-Cauchy distribution. The four locations chosen were Alor Setar, Langkawi, Melaka and Senai. Two performance indicators or goodness of fit tests which are mean circular distance and chord length were used to test which distribution give the best fitting.
MeSH terms: Paper; Probability; Wind; Statistical Distributions; Normal Distribution
Centella asiatica is widely used as a medicinal plant in Malaysia and other parts of the world. In the present study, the growth and uptake of heavy metal by C. asiatica were determined based on the plant exposure to different treatment of metal-contaminated soils under laboratory conditions. Heavy metals uptake in different parts of the plants namely roots, stems and leaves were determined. In general, it was found that the metal uptake capacity followed the order: roots > stems > leaves. Since a close positive relationship was established between the concentrations of metal accumulated in different parts of the plant and the metal levels in the most contaminated soil, C. asiatica has the potential of being used as a biomonitoring plant for heavy metal pollution in the polluted soils.
Ambient groundwater samples collected from five wells in Pulau Tiga have been studied for selected physico-chemical and biological parameters to understand general water quality of the island. This preliminary study on groundwater of Pulau Tiga was undertaken to provide guidance and baseline data for future references. Two field works were undertaken in August and November 2007 to collect the groundwater samples. Groundwater samples were collected from five representatives wells at the low lying area of Pulau Tiga in order to study the in-situ parameters such as DO (dissolved oxygen), EC (electrical conductivity), TDS (total dissolved solids), pH, salinity and temperature. In general, groundwater in Pulau Tiga is moderate in conductivity (330 μS/cm – 1005 μS/cm), and serves as a vital freshwater source to both tourists and local inhabitants. However, bacteriological analysis showed that the groundwater quality was poor, with fecal coliform counts exceeding the WHO permissible limits for drinking water. Through this study, human factor was to be blame for the fecal contamination coliform where the polluted ground water might be originated from sanitation facilities located too close to the wells. The occurrence of total and fecal coliform bacteria in counts suggests poor sanitary handling and warns of the potential presence of disease-causing organisms.
Mild cognitive impairment (MCI) is associated with significant morbidity, especially in the development of Alzheimer’s disease and also related to nutritional factors. A pilot study was carried out to determine antioxidant intake and its relation with MCI among elderly people aged between 60 and 74 years in Klang Valley. Subjects were interviewed to obtain socio-demography data and functional status was evaluated using the Instrumental Activities of Daily Living (IADL). Data on food intake was assessed using the diet history questionnaire and food frequency questionnaire, whilst the Geriatric Depression Scale (GDS) was used to assess depression level. A combination of tests was used to assess cognitive decline, which are Mini-mental State Examination (MMSE), Clock Drawing Test (CDT), and Dementia Rating Scale (DRS). Out of 84 elderly recruited, 70 completed all parts of the study (response rate 83.3%). Mean vitamin E intake was less than the Malaysian RNI (50.0% of RNI for men and 43.0% for women). The incidence of amnestic-MCI (aMCI) was 15.7% among the respondents, while 32.8% were depressed. After adjustment for educational background, beta-carotene intake was found to be significantly (β = 0.325, p<0.05) correlated to cognitive impairment based on CDT scores. The intake levels of antioxidants among subjects were unsatisfactory and beta-carotene intake was related to poor cognitive status based on CDT.
Disinfection of contact lens is an important procedure strongly emphasized by eye care practitioners. There are several types of disinfecting methods. Some methods have been proven to induce parameter changes on soft lenses. These parameter changes are likely to affect the efficacy of contact lens fitting and patients comfort. A self-controlled trial was carried out on a series of disposable soft contact lenses of different material to evaluate parameter changes after cleaning with Lens2® (Automated Lens Cleaner Machine). This will be compared to the lens cleaned conventionally (digital rubbing). Fifty four pieces of soft contact lenses were divided into 2 groups; cleaned conventionally and with Lens2®. Three types of soft contact lenses of different materials were used; Soflens®38, Focus® Monthly and O2 Optix. Each contact lens was cleaned for 30 times to mimic the period of 30 days wear. After the thorough cleaning process, the back optic zone radius (BOZR), back vertex power (BVP), central thickness(ct) and total diameter (TD) were measured. The parameters were statistically analysed to evaluate the changes. There were significant changes in the TD and BVP of Soflens®38 and O2 Optix with both methods. The Focus® Monthly contact lens only showed significant BOZR changes with both methods. However, these parameter changes were not clinically significant because the changes were still in the tolerance range set by ISO (International Organization of Standardization). Both cleaning methods proved to maintain lens parameter within its acceptable range.
Copper phthalocyanine (CuPc) thin films have been prepared using a simple spin coating method. The films were annealed at 5 different temperatures (323, 373, 473, 523 and 573 K) for one hour in air. Optical properties study using the UV-Vis spectrophotometer showed that in the range of wavelength of 300-800 nm, all of the films have identical absorption coefficient patterns and there was no systematic changes with respect to annealing temperature. The film annealed at 373 K showed the highest absorbance while the lowest absorbance was shown by the film annealed at 323 K. The results showed that the optical band gaps depended on the temperature. The film annealed at 373 K has the lowest optical energy gap. Using the five annealed films, solar cell with the configuration of Ag / n-Si / CuPc / Ag were fabricated. Under the 50 W/cm2 light illumination, the current voltage measurements at room temperature were carried out on the device. The device which consists of film annealed at 373 K exhibited the best photovoltaic characteristics. The different annealing temperature also affect the photovoltaic behavior of the devices in a non-systematic way.
The electronic band structure, density of states (DOS) and carrier concentration of a (13,13) metallic and a (13,0) semiconducting Single Wall Carbon Nanotube (SWCNT) have been estimated and simulated by using the Fermi-Dirac distribution function. The energy dispersion E(k) relation for metallic SWCNT near the minimum energy is linear and the Fermi level was independent of temperature (T). On the other hand for semiconducting SWCNT the E(k) relation is parabolic. The normalized Fermi-Energy (EF – EC) in the nondegenerate regime is a weak (logarithmic) function of carrier concentration and varies linearly with T. In the degenerate condition, the Fermi level was independent of T and was a strong function of carrier concentration.
The concentrations of Naturally Occurring Radioactive Material (NORM) and their corresponding terrestrial gamma radiation have been shown to be associated with certain lithology and soil types. A possible relationships among gamma radiation levels, and the lithology and soil types make it possible to predict ionizing radiation level of an area that cannot be directly measured. A study was carried out to statistically predict and validate environmental gamma radiation dose rates based on actual field measurements using a sodium iodide detector. Results obtained showed that the predicted dose rate (Dp) may be determined using a multiple correlation regression equation, Dp = 0.35DL + 0.82 Ds – 0.02, that integrates dose rates contributed by different lithological structures (DL) and soil types (Ds). Statistical analysis on 32 different lithology and soil type combinations showed that more than 50% of the predicted data were not significantly different from the data measured in the field. A predicted isodose map was subsequently plotted base on 4 dose rate classes ranging from 0.1 – 0.3 μSv h-1.
Magnetic paper were prepared via the in situ synthesis method with ferrites in the presence of polyethylenimine (PEI). In this work, the thermomechanical pulp (TMP) fibers were used due to low percentage of collapse lumen and the large lumen size for optimum loading degree. Four cycles of the reaction were performed on the TMP fibers with pH values of 4-10. It was found that variation of pH value played an important role in the loading degree of pulp during synthesis process. The magnetic, morphological and structural properties of the magnetic paper obtained were reported. At the
optimum pH of 6.0, saturation magnetization was found to be 3.08 emu/g, remainance magnetization was 0.11 emu/g and coercive force was 12.64 Oe. The optimum loading degree was found to be 23.25%.
The decolorization of reactive orange 16 dye (RO16) from aqueous solution by CuO/H2O2 was investigated. The amount of dye removed was determined by measuring the concentration of the dye at its characteristic wavelengths by UV-Vis spectrophotometer. The effects of CuO dose, H2O2 concentration and UV light on the decolorization of the dye were investigated. It was found that the removal rate increased with increasing mass of CuO and increasing concentration of H2O2. The combination of CuO, H2O2 and UV light was the best system with dye removal of 100% after 6 h. The removal efficiency observed was in the order: CuO/UV/H2O2 > CuO/H2O2 > CuO/UV = CuO > UV/H2O2 > H2O2 > UV.
Cultivated Bambusa vulgaris of two and four-year old were harvested and studied for their anatomy and physical properties. The anatomy properties between the two age-group of bamboo were observed to have some degrees of variation. This showed that the bamboo anatomy structure has strong correlation with age. The frequency of vascular bundles was greater at the bottom and top portion than in the middle portion of both age-groups. There was no difference in vessel diameter between the two and four-year old culms at the middle of the culms wall thickness. The cell’s wall thickness of both parenchyma and fibre were greater in the 4 year-old than in the 2 year-old culms. In the physical aspect, basic density was found to be higher in the 4 year-old culms than in the 2 year-old by 5 to 8%, and increases from lower to upper internodes showing that there is a maturing process going on between the two age-group relative to the tissue type that they possess.
Various sampling techniques such as hydrodistillation, Soxhlet extraction and solid phase micro extraction (SPME) were used to extract compounds, i.e. the active components attributed to fragrance of C. grandis flowers. Gas chromatograph mass spectrometry was then used to identify and quantify the active components obtained from the techniques. The results thus far showed that, buds and blossoms of this flower which possesses a strong floral-, jasmine- and orange-like aroma contain β-myrcene, limonene, ocimene, linalool and caryophyllene as the major compounds. In hydrodistillation technique the levels of ocimene and linalool detected in blossom were higher than in the bud at 7.37 and 15.93%, respectively, while in the bud, limonene was the highest, i.e. 4.57%. In Soxhlet extraction, however the bud was found to consist of limonene (27.25%), ocimene (5.55%) and linalool (2.97%). The performance of three available SPME fibers was compared to evaluate the recoveries of volatile compounds in C.grandis flowers and 100 μm polydimethylsiloxane was found to be the most effective.
Bottom sediment samples from 30 stations of Pahang River estuary collected in April 2008 were analyzed for the concentration of Pb and Cu using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The average concentrations of Pb and Cu were 74.31 ± 22.97 μg/g dry weights and 18.65 ± 7.65 μg/g dry weights, respectively. In this study, the concentrations were significantly higher near the mouth river and declined as the sampling points were further away from the estuary. Generally, the concentrations of heavy metals were relatively low when compare with other studies in Malaysia. However, the calculated enrichment factors (EF) obtained for Pb, has a slightly higher value, and was probably influenced by anthropogenic input. The concentration for both metals increased with the decrease of mean size, suggesting their association with the fine fraction of the sediments.
This study investigated the spatial pattern and trends of the daily rainfall data in Peninsular Malaysia based on seasonal rainfall indices. Five rainfall indices which describe the main characteristics of rainfall, the total amount of rainfall, frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity, were employed in this study. The statistics of rainfall indices were calculated in terms of their means for four regions in Peninsular Malaysia for the period 1975 to 2004. The findings indicate that the southwest monsoon had the greatest impact on the western part of the Peninsula, particularly in characterizing the rainfall pattern of the northwest region. During this season, the northwest region could be considered as the wettest region since all rainfall indices tested are higher than in other regions of the Peninsula. Otherwise, the northwest region is denoted as the driest part of the Peninsula during the northeast monsoon period. The northwest region is less influenced by the northeast monsoon because of the existence of the Titiwangsa Range, which blocks the region from receiving heavy rainfall. On the other hand, it is found that the lowlands areas such as the eastern part of the Peninsula are strongly characterized by the northeast monsoonal flow. Based on the results of the Mann-Kendall test, as the trend of the total amount of rainfall and the frequency of wet days during the southwest monsoon decrease at most of the stations, the rainfall intensity increases. In contrast, increasing trends in both the total amount of rainfall and the frequency of wet days were observed at several stations during the northeast monsoon, which give rise to the increasing trend of rainfall intensity. The results for both seasons indicate that there are significantly decreasing trends in the frequency of wet days during the extreme events for most of the stations on the peninsula. However, a smaller number of significant trends was found for extreme intensity.
The primary source of water on many small islands is the fragile freshwater lens that floats on saline water in its shallow aquifer. The management of such a limited groundwater resource on these islands is seriously constrained by the occurrence of seawater intrusion. Sipadan Island, the renowned and only oceanic island in Malaysia, had experienced in the over-extraction of its groundwater for more than ten years to cater for freshwater demand associated with tourism activities. This paper discusses the output of modelling of seawater intrusion into the island’s aquifer using SEAWAT-2000. The findings indicated that the island’s coastal aquifer has been encroached by seawater. The infiltration of isochlor (chloride concentration) of 2.5 and 45% of seawater and freshwater mixing ratios has moved 63.4 m and 12.7 m inland from the coastline, respectively. The upconing event at the pumping well, as simulated by the three-dimensional model, showed that 14.5% of seawater-freshwater mixing ratio took place below the bottom of each well. Intensive and unregulated exploitation of groundwater from such an unconfined aquifer of the island by pumping wells contributed to the upconing. In order to protect the fresh groundwater resources in the study area from seawater intrusion, adjustment of groundwater pumping rate is needed. This study showed that the model is useful in demonstrating the mechanism and movement of freshwater-seawater interface in the island, and thus provide a powerful management tool for such an aquifer.
The Malacca Straits is located between Peninsula Malaysia and Sumatra Island. This investigation used equation of motion (Navier-Stokes equation) with the following driving forces: tides, wind of National Centers for Environmental Prediction (NCEP) for year of 2007, salinity and temperature. The equation of motion was solved by means of Hamburg Shelf Ocean Model (HAMSOM). The results for both southwest and northeast monsoon were explained and discussed. The simulation results both for February and August 2007 were relatively similar. Current surface simulation in the Malacca Straits agrees well with the current pattern of previous works. The magnitude of current was between 10-70 cm/s to the northwest. While at the layer 30-50 m in the Malacca Straits, the currents have the magnitude of 10-30 cm/s towards northwest. For the bottom current, the current speed was 0-20 cm/s towards northwest. For the surface and 30-50 m layer, generally the current magnitudes were greater in February compared to those in August. While for the bottom layer, the current magnitudes between February and August were relatively the same.
The objective of the study was to compare the physiological responses among COPD patient to Six Minute Walk Test (6MWT) and Incremental Shuttle Walk Test (ISWT). Twenty subjects were recruited for both 6MWT and ISWT that was carried out randomly. The readings of oxygen saturation (SpO2 ), heart rate (HR) and Modified Borg’s Score (MBS) were being taken before, during (each minute) and after each test. There were no significant difference observed in the peak HR and MBS between 6MWT and ISWT. There was no significant difference observed in the end SpO2 after both tests. In the two tests, HR and MBS increased linearly and were proportionate with time. However, our results showed that the distance walked in both test were significantly different and strongly related with more distance covered in 6MWT, with p < 0.05 (p = 0.01) and R = 0.58. Both 6MWT and ISWT elicited similar peak HRs and MBS suggesting both tests could be used to challenge patient to certain levels of cardiovascular and respiratory stress. There was no significant difference found in this study between the two tests. The two field tests could produce similar physiological responses in COPD patient.
A cross-sectional study was undertaken to determine the refractive and biometric status of premature children without Retinopathy of Prematurity (ROP) and full term children. Fifty eight children between the ages of 3 and 7 years (32 children born premature without ROP and another 26 children born full term and normal) were examined. Refractive error, corneal curvature, axial length, anterior chamber depth and crystalline lens thickness were determined. The results revealed that children between the age of 3 and 7 years were emmetropic, irrespective of whether they were born premature without ROP or full term. However, children born premature without ROP had significantly steeper corneas (t = 3.14, p = 0.0349), shorter axial lengths (t = 3.18, p = 0.0313) and thicker crystalline lens (t = 3.31, p = 0.0256) compared to children born full term within the same age group. This study suggests that compensation in ocular parameters can occur to maintain emmetropia, mainly by adjustment of axial length and corneal curvature.
Stochastic differential equations play a prominent role in many application areas including finance, biology and epidemiology. By incorporating random elements to ordinary differential equation system, a system of stochastic differential equations (SDEs) arises. This leads to a more complex insight of the physical phenomena than their deterministic counterpart. However, most of the SDEs do not have an analytical solution where numerical method is the best way to resolve this problem. Recently, much work had been done in applying numerical methods for solving SDEs. A very general class of Stochastic Runge-Kutta, (SRK) had been studied and 2-stage SRK with order convergence of 1.0 and 4-stage SRK with order convergence of 1.5 were discussed. In this study, we compared the performance of Euler-Maruyama, 2-stage SRK and 4-stage SRK in approximating the strong solutions of stochastic logistic model which describe the cell growth of C. acetobutylicum P262. The MS-stability functions of these schemes were calculated and regions of MS-stability are given. We also perform the comparison for the performance of these methods based on their global errors.