Kajian ini adalah mengenai peranan sterol sebagai penunjuk bio-lipid untuk mengenal pasti variasi dan sumber bahan organik yang hadir bersama sedimen permukaan dari Kuala Selangor, Selangor. Kajian melibatkan kaedah pengekstrakan sterol daripada sampel sedimen dan seterusnya dianalisis menggunakan GC-MS untuk menentukan kehadiran sebatian tersebut. Sepuluh sebatian sterol dikenal pasti hadir dengan fitosterol merupakan sebatian dominan di kawasan kajian iaitu 79% daripada jumlah keseluruhan sterol. Ini diikuti oleh kolesterol serta sterol kumbahan masing-masing menyumbangkan 6% daripada jumlah keseluruhan sterol manakala selebihnya berada dalam julat 1-5%. Indeks Sumber Sterol (SSI) juga menunjukkan kandungan fitosterol yang tinggi walaupun hadir pada kadar yang berbeza di setiap stesen pensampelan. Penilaian pencemaran kumbahan menggunakan nisbah koprostanol/kolesterol, koprostanol/(koprostanol+kholestanol) serta epikoprostanol/koprostanol menunjukkan kawasan kajian tidak mengalami pencemaran kumbahan walaupun sterol daripada sumber kumbahan hadir di persekitarannya. Kesimpulannya sedimen permukaan di Kuala Selangor, Selangor mengandungi campuran sterol daripada pelbagai sumber yang hadir di persekitarannya dengan didominasi oleh fitosterol yang berasal daripada tumbuhan terestrial.
Kandungan alkohol lemak di dalam 19 sampel sedimen permukaan di Sungai Sepang Besar, Sepang, Selangor telah dianalisis menggunakan kromatografi gas-spektrometer jisim (GC-MS). Sebanyak 19 sebatian alkohol lemak dengan julat kepekatan 0.02 μg/g – 9.01 μg/g berat kering dikenalpasti yang terdiri daripada alkohol lemak C12 sehingga C30 termasuk 4 sebatian bercabang. Alkohol lemak C26 mendominasi kebanyakan stesen persampelan dengan julat 0.29 – 5.43 μg/g berat kering, iaitu 15.5% daripada jumlah alkohol lemak. Berdasarkan kepekatan individu sebatian alkohol lemak dan nisbah [Σ(C12 - C20)/Σ(C22 - C30)], Sungai Sepang Besar boleh dikatakan mengandungi alkohol lemak berantai pendek (C12 - C20) yang tinggi berasal daripada organisma marin. Walau bagaimanapun, nilai Indeks Sumber Alkohol (ASI) tidak menunjukkan Sungai Sepang Besar didominasi oleh alkohol lemak rantai pendek kerana faktor kandungan sebatian C26 yang tinggi di kebanyakan stesen persampelan. Nilai nisbah alkohol lemak (rantai ganjil)/(rantai genap) adalah tinggi bagi hampir kesemua stesen persampelan yang dipengaruhi oleh aktiviti bakteria yang tinggi. Dengan itu dapat disimpulkan bahawa sedimen permukaan Sungai Sepang Besar mengandungi campuran bahan organik yang berasal dari marin, terestrial dan bakteria.
The application of the Variance Targeting Estimator (VTE) is considered in GJR-GARCH(1,1) model, under three
misspecification scenarios, which are, model misspecification, initial parameters misspecification and innovation
distribution assumption misspecification. A simulation study has been performed to evaluate the performance of VTE
compared to commonly used, which is the Quasi Maximum Likelihood Estimator (QMLE). The data has been simulated
under GJR-GARCH(1,1) process with initial parameters ω = 0.1, α = 0.05, β = 0.85, γ = 0.1 and an innovation with a
true normal distribution. Three misspecification innovation assumptions, which are normal distribution, Student-t
distribution and the GED distribution have been used. Meanwhile, for the misspecified initial parameters, the first initial
parameters have been setup as ω = 1, α = 0, β = 0 and γ = 0. Furthermore, the application of VTE as an estimator has
also been evaluated under real data sets and three selected indices, which are the FTSE Bursa Malaysia Kuala Lumpur
Index (FBMKLCI), the Singapore Straits Time Index (STI) and the Jakarta Composite Index (JCI). Based on the results, VTE
has performed very well compared to QMLE under both simulation and the applications of real data sets, which can be
considered as an alternative estimator when performing GARCH model, especially the GJR-GARCH.
Haloacetic acids (HAAs) are one of the most common disinfection by-products formed during chlorination of drinking water. An analytical method involving solid phase extraction (SPE) followed by gas-chromatograph mass-spectrometry (GC-MS) was developed and optimized using experimental design to determine the HAAs in water. Selectivity, percent recovery, and detection limit studies were carried out on a Silia-SAX (Trimethyl ammonium chloride) SPE. Under optimized conditions, average recoveries for nine HAAs spiked in drinking water samples range from 69.2% to 108.2 %. The relative
standard deviation (RSD) data were found to range from 2.5 % to 12.5% based upon five repeat recovery experiments and detection limit range of 0.16 to 0.009μg/l were obtained. On this basis, SPE was studied as a possible alternative to liquid-liquid extraction (LLE) for the analysis of HAAs in water. The performance of the SPE-GC-MS with actual water samples was tested.
Omega-3 polyunsaturated fatty acids (PUFAs) is crucial to prevent a wide range of chronic diseases from a global view point. However, no suitable dietary assessment tool is available for usage among Malaysian population. The present study aimed to evaluate the validity of interviewer-administered semi-quantitative Food Frequency Questionnaire (FFQ) for assessing the omega-3 PUFAs intake among the Malays and Chinese elderly individuals in Klang Valley, Malaysia. Thirty-seven elderly people (54.1% women and 45.9% men), aged 60 years and above, were recruited from a community setting. Omega-3 PUFAs intake for the past one month was assessed using a 45-food item FFQ and validated against 3 days Food Record (FR). Wilcoxon signed rank test indicated no significant mean intake difference between two assessment methods. Significant correlation was found for total omega-3 PUFAs (r=0.926), α-linolenic acid (ALA) (r=0.745), eicosapentaenoic acid (EPA) (r=0.579) and docosahexaenoic acid (DHA) (r=0.912). Bland-Altman analysis exhibited no apparent systematic bias between the two methods for total omega-3 PUFAs intake, while quartile analysis classified 73% subjects assigned into the same quartile. Conclusively, the newly-developed FFQ yielded a reasonable validity in the tested population and provided a convenient means to estimate omega-3 PUFAs intake within healthy Malays and Chinese elderly individuals. Further study to evaluate its validity and reproducibility for different age groups is required.
The goal of this study was to examine the reliability and validity of the Bahasa Malaysia version of the Montreal cognitive assessment (MoCA-BM) and to determine its optimal cut-off score among older adults with mild cognitive impairment (MCI), after adjustments for age, gender, levels of education, physical functioning and depressive symptoms. A total of 2237 community dwelling older adults aged 60 years and above were randomly selected for the study, excluding those with MMSE score below 14. Instruments administered were the MoCA-BM, the Malay Mini-Mental State Examination (MMMSE), the Rey Auditory Verbal Learning Test (RAVLT), the Digit Span and the Digit Symbol subtests of the Wechsler Adult Intelligence Scale (WAIS), activities of daily living (ADL) and the Geriatric Depression Scale (GDS). MCI were determined using the Petersen’s 2014 criteria as the gold standard. SPSS version 22 was used for reliability and validity analysis and optimal cut-off score detection. Cronbach’s α of the MoCA-BM was 0.691 and concurrent validity was high between MoCA-BM and MMMSE scores (r=0.741). Optimal cut-off point for MoCA-BM to detect MCI among older adults in Malaysia was 17/18, with sensitivity of 68.2% and specificity of 61.3%. Using this cut-off, 38.9% of participants were detected to be at risk of MCI. In conclusion, MoCA-BM is a reliable and valid screening instrument for MCI among Malaysian elderly community. The newly derived optimal cut-off for MCI is much lower than the original MoCA with modest ability to discriminate between normal and MCI older adults in the community.
The study monitored the characteristics of the leachate collected from ten different landfills and presented the experimental work for the treatment of leachate by immobilized Trametes menziesii. Variation in biological oxygen demand (BOD), chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N) showed that the age of the leachate has a significant effect on its characteristics and composition. The BOD5/COD ratio tends to decrease as the age of leachate increases, varying from 0.71 for a relatively 'fresh' leachate to 0.62 for an older (more stabilized) one. Variations in the characteristics of the leachate suggested that these leachates are difficult to treat. The principal pollutants in the leachate samples were organic and ammonia loads. Treatment of leachate using immobilized Trametes menziesii achieved 89.14 and 2.11% removals for leachate BOD5 and COD, respectively. These findings suggested that using immobilized Trametes menziesii can remove promising percentage of BOD and COD leachate.
A zinc oxide (ZnO) pilot plant furnace was used to synthesize ZnO nanoparticles at very high capacities in a range of 1-4 t/month. The 4-t custom-designed furnace was used to synthesize ZnO particles possessing primary nanoparticles resembling rods and grains. At a combustion temperature of 1000-1300°C, zinc vapour was oxidized into ZnO powder in order to produce granular ZnO (ZG) particles. By blowing air into the combustion chamber, ZnO nanorods (ZR) were produced. The ZR specimen exhibited higher XRD intensities, stronger photocatalysis and higher electrical resistance compared to that of ZG sample. However, the ZR sample showed a stronger toxicity to marine phytoplankton, Isochrysis galbana, by starting to inhibit cell growth at 8 mg/L ZnO concentration in seawater whereas ZG sample started showing growth inhibition at a higher ZnO concentration of 32 mg/L. The toxicity of ZnO primary nanoparticles was probably attributed to the dissolution, release and uptake of free zinc ions especially for the case of the higher surface area of ZR particles that exhibited relatively higher zinc concentration on the particle surface, based on the elemental mapping of the electron spectroscopy imaging results.
Computer simulations is now becoming a common feature in many underÂgraduate physics textbook together with online supplements to supposedly enhance learning and understanding. Many questions arise as to how these computer simulations and online supplements are developed and is it a worthy investment on the part of the physics educators. In this paper we look at the ways how "Physlets" (Physics Applets) are developed for the purpose of the undergraduate physics curriculum. JAVA is the fastest-growing proÂgramming language today. In scientific programming, the JAVA language meets the need for a simpler object-oriented language than C++ but is not yet popular, useful and widely used in very large scale or number crunching physics simulations. One of JAVA applets’s strength is that it is device independent. And for physics learning, simulation applets embedded in World Wide Web pages allow interactive learning and students-programmable demonstrations. We will examine a few physics simulations using JAVA applets that we have developed. We also discuss the various different aspects of using JAVA applets in developing physics simulation. And finally we will look into the reasons as to why it is still not ready for use in intensive physics simulation.
The uniaxial compressive strength (UCS) is one of the most common mechanical parameters required in geotechnical engineering to characterize the compressive strength of rock material. Measurements of UCS are expensive, time consuming, destructive and thus, not favorable in the presence of limited samples. Therefore, a simple yet practical application is needed for the estimation of UCS. This research presents two correlations to predict UCS values for granite and schist by using ultrasonic velocity travel time (tp) from ultrasonic tests. The validity of the practical approach presented in this research is confirmed based on the strong correlations developed from the experimental tests conducted. For the entire data set, the correlation between UCS and ultrasonic velocity travel time was expressed as UCS = 217.2 e-0.016(tp) for granite and UCS = 1110.6 e-0.037(tp) for schist and the coefficient of determination (R2) value for both granite and schist is 0.93. These correlations may be useful for applications related to geotechnical engineering designs.
Tiga spesies ikan air tawar iaitu Rasbora sumatrana (Cyprinidae), Poecilia reticulata (guppy; Poeciliidae) dan Carrasius
auratus telah didedahkan kepada kromium (Cr) dan selenium (Se) yang mempunyai julat kepekatan yang berbeza selama
4 hari (96 jam) di dalam makmal. Kadar kematian dicatatkan dan kepekatan kematian ambang (LC50) dan masa kematian
ambang (LT50) dihitung. Nilai LC50 kepekatan kematian median (LC50) dan masa kematian median (LT50) didapati
berkurang dengan peningkatan kepekatan logam dan masa pendedahan bagi kesemua spesies ikan. Nilai LC50 bagi
pendedahan selama 96 jam bagi R. sumatrana, P. reticulata dan C. auratus kajian ini masing-masing bagi Cr adalah
20.91, 19.85, 28.31 mg/L dan bagi Se pula 0.21, 3.03, 0.24 mg/L. Se mempamerkan ketoksikan paling tinggi terhadap
tiga spesies ikan air tawar ini apabila mempunyai nilai LC50 96 jam paling rendah jika dibandingkan dengan Cr.
Ammonium-enriched skim latex serum - used for absorption of contaminating ammonia gas - when composted with other rubber tree wastes, is promising as a good compost. The objective of this research was to utilize ammonium-enriched skim latex serum (S) as a raw composting ingredient after being combined with para sawdust (W1) and para rubber leaves (W2). Several ratios of S, W1 and W2 were experimented in a 15L composting vessel to determine the most effective compost. The best ratio was found to be 3:1:3 by weight at 12-day retention. The modified 30 L composting reactor employed with the derived optimum mixing conditions yielded N, P and K of 2.40, 1.51 and 14.84 %w/w. The growth of Brassica alboglabra after application of this compost combined with a chemical fertilizer generated the highest fresh weight (4.48 g/plant). Thus, compost from these wastes could be used as a fertilizer and logically should contribute to cost saving of waste disposal.
A study was conducted to investigate the possibility of employing a single intramuscular injection of a synthetic hormone analogue, ovupin on the induced breeding of two major carps, viz. rohu (Labeo rohita), mrigala (Cirrhinus mrigala) and an endangered minor carp, bata (Labeo bata). Three breeding trials of each species were performed. In case of major carp, the females were injected with single dose of ovupin solution at a rate of 0.5 mL kg-1 body weight, while the minor carp received ovupin solution at a dose of 0.3 mL kg-1 body weight, whereas males received extracted PG hormone at a dose of 2 and 1.5 mg kg-1 body weight for major carps and minor carp, respectively. All the three species were successfully bred using ovupin through a single injection. In case of major carps, the latent period was 9-10 h while 12-14 h for minor carp. The breeding response of females was 100% in major carps, whereas it was approximately 90% in minor carp. Fertilization rate varied between 87.07 and 89.94% for the major carps and between 87.6 and 89.9% for minor carps. Major carps showed higher hatching rates (77.21 to 80.19%) than minor carp (64.9 to 66.56%). The present study indicated that ovupin could be effective as alternative of PG in carp’s breeding in Bangladesh.
Penanaman semula hutan paya bakau dipertimbangkan sebagai satu usaha terbaik bagi melindungi dan memelihara kawasan pesisir pantai. Dalam kajian ini sejumlah 180 anak benih Bruguiera cylindrica telah ditanam di kawasan pesisir pantai Pulau Carey. Dua set eksperimen daripada segi corak dan medium dilakukan dengan 3 plot replika bagi setiap rawatan dengan kaedah Blok Rawak Lengkap. Kadar keterushidupan anak bakau B. cylindrica dicatat setiap 2 minggu selama 20 minggu. Keputusan menunjukkan corak penanaman secara kelompok adalah lebih sesuai (20%). Anak bakau yang ditanam secara langsung di atas tanah menunjukkan kadar hidup yang lebih tinggi (30%). Namun ujian analisis ANOVA menunjukkan tiada perbezaan yang signifikan antara ketiga-tiga corak taburan penanaman dan penggunaan medium yang berbeza ini terhadap keterushidupan anak bakau B. cylindrica.
Environmental health in general is referring to the aspect of concern on healthy environment, and the interrelations between environment and human health. Due to the urbanization, urban development is changing the natural environment into a man-made environment. Along with the process, level of environmental quality and human health are decreased. Air quality as reference shows that urban ambient air is more polluted than rural. Due to high density of human population and their activities in urban areas, it produces air pollutants with higher rate as compared to less-developed areas. Air pollutants contribute to various health problems. People suffering from respiratory diseases are the most likely to be affected by air pollution. This paper aimed to examine the rate of respiratory infection among residents in an urban growth corridor (Petaling Jaya-Shah Alam-Klang) and the relationship with the urban land uses, traffic volume and air quality. There were four major types of data used in this study i.e., respiratory infection of the respondents, air quality, land use and traffic volume. A health questionnaire survey was carried out besides the secondary data collection from the various government departments. Relationship analysis was performed between respiratory health and the urban factors (air quality, traffic volume and land uses). The study found out that the relationship between the respiratory health and the urban factors is different in city-wide land use and traffic factors, as compared to the localised air quality and land use factors. To conclude, the urban factors are potentially affecting the respiratory health.
Air environmental health indicators were defined operationally as a combination of “air quality” and “air-related health” indicators. Clean air is a basic precondition of human health. Air pollutants had been identified with potential negative impact on health especially on respiratory and cardiovascular diseases. Thus, studies are necessary to identify and understand the state of environmental health. This study was aimed to examine and analyse the air environmental health condition in city of Kuala Lumpur by using a set of indicators. House to house questionnaire survey was carried out to collect air-related health data, and air quality sampling was carried out to identify ambient air quality level of the city. In general, city of Kuala Lumpur was found to have a “moderate level” of air quality. Air-related illnesses indicated by acute respiratory infection and asthma were found to be higher in more developed or higher density zones, as compared to other zones. Besides, air-related illnesses were significantly correlated to respondents’ exposure to air pollution. The findings imply that human health can be improved by managing the urban development and its environmental quality properly.
The convergence property for doing logic programming in Hopfield network can be accelerated by using new relaxation method. This paper shows that the performance of the Hopfield network can be improved by using a relaxation rate to control the energy relaxation process. The capacity and performance of these networks is tested by using computer simulations. It was proven by computer simulations that the new approach provides good solutions.
Induced magnetic field stagnation point flow for unsteady two-dimensional laminar forced convection of water based nanofluid containing microorganisms along a vertical plate has been investigated. We have incorporated zero mass flux boundary condition to get physically realistic results. The boundary layer equations with three independent variables are transformed into a system of ordinary differential equations by using appropriate similarity transformations. The derived equations are then solved numerically by using Maple which use the fourth-fifth order Runge-Kutta-Fehlberg algorithm to solve the system of similarity differential equations. The effects of the governing parameters on the dimensionless velocity, induced magnetic field, temperature, nanoparticle volume fraction, density of motile microorganisms, skin friction coefficient, local Nusselt number and motile density of microorganisms transfer rate are illustrated graphically and tabular form. It is found that the controlling parameters strongly affect the fluid flow and heat transfer characteristics. We compare our numerical results with published results for some limiting cases and found excellent agreement.
The unsteady laminar boundary layer flow of a nanofluid and heat transfer over a permeable shrinking cylinder using the Buongiorno’s nanofluid model is investigated. Using a similarity transformation, the governing partial differential equations are transformed into a system of ordinary differential equations and then solved numerically using a shooting method. The numerical results are obtained for velocity, temperature and concentration profiles as well as the skin friction coefficient, the local Nusselt number and the local Sherwood number. Dual solutions are found to exist in a certain range of the suction and unsteadiness parameters. It is observed that suction parameter increase both the skin friction coefficient and the heat transfer rate at the surface, whereas the opposite trend is obtained for the Sherwood number. It is also observed that suction widens the range of the unsteadiness parameter for which the solution exists.
The unsteady mixed convection boundary layer flow near the forward stagnation point of a two-dimensional symmetric body prescribed by a uniform heat flux rate is studied in this paper. The main aim of the investigation is to identify situations in which dual solutions for the steady-state flow can be determined when the flow is opposing. It is also shown that there is a smooth transition from the unsteady initial flow (short time) to the final steady state flow (large time).