Displaying publications 1 - 20 of 390 in total

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  1. Koh HL, Lim PE
    Environ Monit Assess, 1991 Oct;19(1-3):373-82.
    PMID: 24233954 DOI: 10.1007/BF00401326
    Georgetown of Penang, an old city, is noted for its narrow streets. The existing traffic dispersal system is utterly inadequate to cope with the ever increasing number of cars and motorcycles on the road. The principal objective of this study is to build prediction models of CO to be employed as one of the planning tools in the future design of Penang urban traffic dispersal system. This study involves the monitoring of kerbside CO levels at selected sites and the fitting of hourly-averaged CO data to linear regression models incorporating the residual effect of CO emission due to traffic in the earlier periods and also different categories of vehicles. The best overall regression model appears to be the one based upon the total traffic count of motorcycles. This can be accounted for by the fact that the traffic counts of motorcycles and cars are highly correlated in most cases and that the emissions of CO from motorcycles are more readily detected as they travel closer to the kerb. The inclusion of residual CO in the models significantly improves the correlation coefficient from about 0.4 to about 0.7.
    Matched MeSH terms: Linear Models
  2. Kurtz ME, Johnson SM, Ross-Lee B
    Int J Health Serv, 1992;22(3):555-65.
    PMID: 1644515 DOI: 10.2190/JFRP-E61C-Y7R7-G7J8
    This study investigated knowledge, attitudes, and preventive efforts of Malaysian college students regarding health risks associated with passive smoking, as well as possible directions for intervention and health education programs. Students responded anonymously to a structured written questionnaire. Statistical analyses were conducted to examine (1) differences in knowledge, attitudes, and preventive efforts between smokers and nonsmokers and between men and women; (2) the relationship between smoking by parents, siblings, and friends, and students' knowledge, attitudes, and preventive efforts; and (3) relationships between knowledge, attitudes, and preventive efforts. Peer groups and siblings had a substantial influence on students' attitudes toward passive smoking and their preventive efforts when exposed to passive smoke. A regression analysis revealed a statistically significant linear dependence of preventive efforts on knowledge and attitudes, with the attitude component playing the dominant role. This research suggests that educational efforts on passive smoking, directed toward young college students in developing countries such as Malaysia, should concentrate heavily on changing attitudes and reducing the effects of peer group and sibling influences.
    Study site: Institut Teknologi Mara, Shah Alam; Stamford College, Petaling Jaya; Selangor, Malaysia
    Matched MeSH terms: Linear Models
  3. Singh R, Singh HJ, Sirisinghe RG
    PMID: 7855654
    Spirometry was performed on 1,485 male subjects ranging in age from 13 years to 78 years and comprising of all the main ethnic groups in Malaysia. They were divided into six age categories. Mean forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were 3.45 +/- 0.02 and 3.10 +/- 0.02, respectively. Both FVC and FEV1 correlated negatively with age. Regression analysis revealed an age-related decline in FVC of 295 ml per decade of life. Multiple stepwise regression of the data for the prediction of an individual's FVC above the age of 20 years gave the equation FVC (1) = 0.0404 (height in cm)-0.0295 (age in years)-2.2892. Predicted FVC values derived from equations based on other populations were considerably higher than the observed mean in this study. This study therefore, reemphasises the need to be cautions when applying formulae derived from one population to another. Grossly erroneous conclusions may be reached unless predicted equations for lung-function tests for a given population group are derived from studies based upon the same population group.
    Matched MeSH terms: Linear Models
  4. Ismail R, Rahman AF, Chand P
    J Clin Pharm Ther, 1994 Aug;19(4):245-8.
    PMID: 7989403
    We estimated individual and population Michaelis-Menten pharmacokinetic parameters for phenytoin (DPH) in epileptic patients attending our neurology clinic using the computer programme. OPT. Our results agreed well with literature values but were lower than those we obtained earlier in a smaller number of patients. The Km was independent of age, weight and sex but there was a weak, correlation between Vm and body weight. We conclude that the use of population Vm and Km in normograms could lead to errors in DPH dose estimations as they correlated very poorly with patient characteristics. OPT was easy to use and sufficiently accurate for deriving dose estimates in routine patients. Its use would enable practitioners to generate their patients' own parameters for use in individual dosage adjustments. The estimates can subsequently be updated as more data become available.
    Matched MeSH terms: Linear Models
  5. Gan CY
    PMID: 8629063
    A survey was conducted to document and bring attention to the use of smokeless tobacco among rural Kadazan women in Sabah, East Malaysia. Of the 472 women interviewed, 59.5% had used tobacco among the ingredients that they habitually chewed. Women with low education were more likely to be chewers. The chewing habit was usually acquired during the teenage years and the practice was perceived mainly as a cultural norm. 73.3% of these smokeless tobacco users were unaware of any adverse health effect of this type of tobacco use as compared to 53.9% of the non-tobacco users. The high prevalence of smokeless tobacco use is easily maintained as tobacco is cheap, locally produced and its use is socially accepted. The low level educational status of the women compounds the problem and intervention programs to curb this form of tobacco use is warranted.
    Matched MeSH terms: Linear Models
  6. Radin UR, Mackay MG, Hills BL
    Accid Anal Prev, 1996 May;28(3):325-32.
    PMID: 8799436
    Preliminary analysis of the short-term impact of a running headlights intervention revealed that there has been a significant drop in conspicuity-related motorcycle accidents in the pilot areas, Seremban and Shah Alam, Malaysia. This paper attempts to look in more detail at conspicuity-related accidents involving motorcycles. The aim of the analysis was to establish a statistical model to describe the relationship between the frequency of conspicuity-related motorcycle accidents and a range of explanatory variables so that new insights can be obtained into the effects of introducing a running headlight campaign and regulation. The exogenous variables in this analysis include the influence of time trends, changes in the recording and analysis system, the effect of fasting activities during Ramadhan and the "Balik Kampong" culture, a seasonal cultural-religious holiday activity unique to Malaysia. The model developed revealed that the running headlight intervention reduced the conspicuity-related motorcycle accidents by about 29%. It is concluded that the intervention has been successful in improving conspicuity-related motorcycle accidents in Malaysia.
    Matched MeSH terms: Linear Models
  7. Razak AA, Harrison A
    J Prosthet Dent, 1997 Apr;77(4):353-8.
    PMID: 9104710
    Dimensional accuracy of a composite inlay restoration is important to ensure an accurate fit and to minimize cementation stresses.
    Matched MeSH terms: Linear Models
  8. Ho TM, DeBruynne J, Ahamad M, Darussamin H
    Asian Pac J Allergy Immunol, 1997 Sep;15(3):123-6.
    PMID: 9438543
    The MAST CLA system was evaluated against skin prick test (SPT) for diagnosis of allergies to house dust mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cats. Forty three asthmatic children were examined by SPT and MAST CLA. Chi-square analysis indicated significant association between SPT and MAST CLA results for the house dust mites but not for cats. The sensitivities of MAST CLA for house dust mites and cats were 100 and 25% respectively; specificities were all less than 50%. The efficiency of MAST CLA for detection of allergy to the house dust mites was 88% and 44% for cats. A significant linear correlation was found between SPT wheal size and MAST CLA grade for D. farinae but not for D. pteronyssinus and cats. It is concluded that the MAST CLA allergy system can be used to supplement SPT for diagnosis of allergies to house dust mites but not to cats.
    Matched MeSH terms: Linear Models
  9. Johan A, Chan CC, Chia HP, Chan OY, Wang YT
    Eur Respir J, 1997 Dec;10(12):2825-8.
    PMID: 9493668
    Maximal static inspiratory and expiratory mouth pressures (PI,max and PE,max, respectively) enable the noninvasive measurement of global respiratory muscle strength. The aim of this study was primarily to obtain normal values of PI,max and PE,max for adult Chinese, Malays and Indians and, secondarily, to study their effect on lung volumes in these subjects. Four hundred and fifty two healthy subjects (221 Chinese, 111 Malays, 120 Indians) were recruited. Measurements of PI,max from residual volume (RV), PE,max from total lung capacity (TLC) and forced vital capacity (FVC) were obtained in the seated position. There were significant ethnic differences in PI,max and PE,max measurements obtained in males, and FVC measurements in both males and females. Chinese males had higher PI,max values (mean (+/-SD) 88.7+/-32.5 cmH2O) and higher PE,max values (113.4+/-41.5) than Malay males (PI,max 74.0+/-22.7 cmH2O, PE,max 94.7+/-23.4 cmH2O). Chinese males had higher PE,max than Indian males (PI,max = 83.7+/-30.0 cmH2O, PE,max 98.4+/-29.2 cmH2O). There were no significant differences among Chinese females (PI,max 53.6+/-2.3 cmH2O, PE,max 68.3+/-24.0 cmH2O), Malay females (PI,max 50.7+/-18.3 cmH2O, PE,max 63.6+/-21.6 cmH2O) and Indian females (PI,max 50.0+/-15.2 cmH2O, PE,max 60.7+/-20.4 cmH2O). In both sexes, the Chinese had a higher FVC compared with Malays and Indians. After adjusting for age, height and weight, race was still a determinant for PE,max in males, and FVC in both sexes. The FVC only correlated weakly with PI,max and PE,max in both sexes. Ethnic differences in respiratory muscle strength, and lung volumes, occur among Asians. However, respiratory muscle strength does not explain the differences in lung volumes in healthy Asian subjects.
    Matched MeSH terms: Linear Models
  10. Habshah Binti Midi
    A robust MM estimates for the linear model is revisited. This estimates are defined by a three-stage procedures and posses the following properties: (i) they are highly efficient when the errors have a normal distribution and (ii) their breakdown-point is 0.5. A numerical examples are used to show that the MM estimates has a higher breakdown point and is more efficient than The RLS (Reweighted Least Squares Regression based on The Least Median Squares) estimates.
    Suatu penganggar teguh dalam model linear dinamakan Penganggar MM diperkenalkan kembali. Penganggar ini ditakrifkan menerusi pendekatan 3 peringkat dan mempunyai sifat sifat seperti berikut: i) kecekpan yang tinggi sekiranya ralat tertabur secara normal dan ii) titik musnah bersamaan 0.5. Contoh berangka telah digunakan ulituk menunjukkan bahawa penganggar ini mempunyai titik musnah yang tinggi dan lebih cekap daripada penganggar KDTB (Penganggar Kuasadua Terkecil Berpemberat berdasarkan Kaedah Kuasadua Terkecil).
    Matched MeSH terms: Linear Models
  11. Rao PV, Ahuja MM, Trivedi BB, Ramachandran M, Samal KC, Zain AZ, et al.
    J Indian Med Assoc, 1998 May;96(5):155-7.
    PMID: 9828573
    Matched MeSH terms: Linear Models
  12. Chattopadhyay A
    Demography, 1998 Aug;35(3):335-44.
    PMID: 9749325
    With data from the Malaysian Family Life Survey, I use a continuous-state hazards model to study the impact of migration on the dynamics of individuals' careers. I distinguish between the effects of family migration and solo migration by gender. The results show that migration alters the career trajectory primarily by accelerating the process of occupational mobility rather than by increasing the level of occupational attainment. Further, the effect of migration on careers varies by type of migration, especially for women. Male-female differences in the outcome of family migration, however, are visible only in transitions into and out of employment.
    Matched MeSH terms: Linear Models
  13. Noorhassim I, Rampal KG
    Am J Otolaryngol, 1998 8 6;19(4):240-3.
    PMID: 9692632
    PURPOSE: To determine the combined effect of smoking and age on hearing impairment.

    MATERIALS AND METHODS: Pure tone audiometry test was conducted on 263 residents of a rural village who were not exposed to noise. The pack-years of smoking were computed from the subjects' smoking history. The association between pack-years and hearing impairment was assessed. The combined effect of smoking and age on hearing impairment was determined based on prevalence rate ratio.

    RESULTS: There was a statistically significant trend in the number of pack-years of smoking and age as risk factors for hearing impairment. The prevalence rates of hearing impairment for nonsmokers aged 40 years and younger, smokers aged 40 years and younger, nonsmokers older than 40 years of age, and smokers older than 40 years of age were 6.9%, 11.9%, 29.7%, and 51.3%, respectively. The prevalence rate ratio for nonsmokers aged 40 years and younger, smokers aged 40 years and younger, nonsmokers older than 40 years of age, and smokers older than 40 years of age (nonsmokers aged 40 years and younger as a reference group) was 1, 1.7, 4.3, and 7.5, respectively. The prevalence rate ratios showed a multiplicative effect of smoking and age on hearing impairment.

    CONCLUSION: Age and smoking are risk factors for hearing impairment. It is clear that smoking and age have multiplicative adverse effects on hearing impairment.

    Matched MeSH terms: Linear Models
  14. Gumel AB, Kubota K, Twizell EH
    Math Biosci, 1998 Aug 15;152(1):87-103.
    PMID: 9727298
    A sequential algorithm is developed for the non-linear dual-sorption model developed by Chandrasekaran et al. [1,2] which monitors pharmacokinetic profiles in percutaneous drug absorption. In the experimental study of percutaneous absorption, it is often observed that the lag-time decreases with the increase in the donor concentration when two or more donor concentrations of the same compound are used. The dual-sorption model has sometimes been employed to explain such experimental results. In this paper, it is shown that another feature observed after vehicle removal may also characterize the dual-sorption model. Soon after vehicle removal, the plots of the drug flux versus time become straight lines on a semilogarithmic scale as in the linear model, but the half-life is prolonged thereafter when the dual-sorption model prevails. The initial half-life after vehicle removal with a low donor concentration is longer than that with a higher donor concentration. These features, if observed in experiments, may be used as evidence to confirm that the dual-sorption model gives an explanation to the non-linear kinetic behaviour of a permeant.
    Matched MeSH terms: Linear Models
  15. Smith JD
    Math Biosci, 1998 Nov;153(2):151-61.
    PMID: 9825637
    The Gibbs canonical ensemble of statistical mechanics is used to describe the probability distribution of the age classes of mothers of new-borns in an age-structured population. The Malthusian parameter emerges as a Lagrange multiplier corresponding to a generation time constraint, while a new perturbation parameter appears as the Lagrange multiplier corresponding to a maternity constraint. Classical Lotka stability reduces to the unperturbed case of the more general canonical ensemble model. The model is used in a case study of the female (peninsular) Malaysian population of 1970. The Malthusian parameter and perturbation are calculated easily by linear regression. Use of the model identifies an anomaly in the population due to the effects of World War II.
    Matched MeSH terms: Linear Models
  16. Raj SM, Naing NN
    PMID: 10772554
    A study to determine the effect of antihelminthic treatment on growth and nutritional status was undertaken on 103 children in the second grade of primary school, 71 of whom were found to be infected with Ascaris lumbricoides or Trichuris trichiura. The median Ascaris and Trichuris intensities in the infected group were 19,600 (range; 0-488,000) and 2,800 (range; 0-84,600) eggs per gram of feces respectively. Forty-three children harbored both types of worm. Fourteen weeks after two 400 mg doses of albendazole were administered to infected children, the increases in weight, height, weight for age, height for age and weight for height were significantly higher among infected children than controls who were uninfected at baseline. The observed gains were independent of sex and socioeconomic status. Decrease in log transformed Trichuris intensity correlated with increases in weight (r=0.24; p=0.02) and weight for age (r=0.20; p=0.06) but decrease in Ascaris intensity did not correlate with increases in any of the anthropometric parameters. The results suggest that antihelminthic treatment has beneficial short-term effects on growth and nutritional status of a modest magnitude among early primary schoolchildren in the area.
    Matched MeSH terms: Linear Models
  17. Pollack RJ, Kiszewski A, Armstrong P, Hahn C, Wolfe N, Rahman HA, et al.
    Arch Pediatr Adolesc Med, 1999 Sep;153(9):969-73.
    PMID: 10482215 DOI: 10.1001/archpedi.153.9.969
    BACKGROUND: Pediculiasis is treated aggressively in the United States, mainly with permethrin- and pyrethrin-containing pediculicides. Increasingly frequent anecdotal reports of treatment failure suggest the emergence of insecticidal resistance by these lice.

    OBJECTIVE: To confirm or refute the susceptibility of head lice sampled in the United States to permethrin.

    DESIGN: Survey. Head lice were removed from children residing where pediculicides are readily available and where such products are essentially unknown. Their survival was compared following exposure to residues of graded doses of permethrin in an in vitro bioassay.

    SETTING: School children from Massachusetts, Idaho, and Sabah (Malaysian Borneo).

    SUBJECTS: In the United States, 75 children aged 5 to 8 years. In Sabah, 59 boys aged 6 to 13 years. Virtually all sampled US children had previously been treated with pediculicides containing pyrethrins or permethrin; none of the Sabahan children were so exposed.

    MAIN OUTCOME MEASURE: Survival of head lice exposed to permethrin.

    RESULTS: Permethrin did not affect head lice sampled from chronically infested US children who had previously been treated for pediculiasis. The slope of the dose-response regression line for these lice did not differ significantly from zero (P = .66). This pediculicide immobilized lice sampled in Sabah. Mortality correlated closely with permethrin concentration (P = .008).

    CONCLUSIONS: Head lice in the United States are less susceptible to permethrin than are those in Sabah. The pyrethroid susceptibility of the general population of head lice in the United States, however, remains poorly defined. Accordingly, these relatively safe over-the-counter preparations may remain the pediculicides of choice for newly recognized louse infestations.
    Matched MeSH terms: Linear Models
  18. Malays J Nutr, 1999;5(1):-.
    MyJurnal
    A longitudinal study was conducted to relate basal metabolic rate (BMR) with growth during adolescence. Subjects comprise 70 boys and 69 girls aged between ten and thirteen years at the time of recruitment. Parameters studied include anthropometric measurements and BMR, which was measured by indirect calorimetry using the Deltatrac metabolic monitor. Measurements were carried out serially once every six months, with a total of 713 BMR data points collected over three years. Mean BMR of boys aged 11, 12, 13 and 14 years were 4.96 ± 0.63 MJ/day, 5.28 ± 0.71 MJ/day, 5.73 ± 0.68 MJ/day and 5.92 ± 0.63 MJ/day, respectively; while mean BMR of girls in the 10, 11, 12 and 13 year age groups were 4.96 ± 0.63 MJ/day, 4.85 ± 0.63 MJ/day, 5.05 ± 0.55 MJ/day and 4.94 ± 0.51 MJ/day, respectively. Comparison of measured BMR with BMR values predicted from the FAO/WHO/UNU (1985) equations shows that the predictive equations overestimated the BMR of Malaysian boys by 3% and that of girls by 5%. The Henry & Rees (1991) equations for populations in the tropics underestimated BMR of boys and girls by 1% and 2%, respectively. Linear regression equations to predict BMR based on body weight were derived according to sex and age groups. It is recommended that these predictive equations be used for the estimation of BMR of Malaysian adolescents.
    Matched MeSH terms: Linear Models
  19. Ismail IS, Nazaimoon WM, Mohamad WB, Letchuman R, Singaraveloo M, Pendek R, et al.
    Diabetes Res Clin Pract, 2000 Jan;47(1):57-69.
    PMID: 10660222 DOI: 10.1016/s0168-8227(99)00104-7
    Recent studies have shown that good glycaemic control can prevent the development of diabetic complications in type 1 and type 2 diabetes. We wished to observe the glycaemic control in patients from different centres in Peninsular Malaysia and the factors that determine it. We recruited 926 patients with diabetes diagnosed before age 40 years from seven different centres, with proportionate representation from the three main ethnic groups. Clinical history and physical examination were done and blood taken for HbA1c and fasting glucose. The overall glycaemic control was poor with geometric mean HbA1c of 8.6% whilst 61.1% of the patients had HbA1c greater than 8%. Glycaemic control in patients with type 2 diabetes varied between various centres and ethnic groups, with the best control obtained in Chinese patients. Significant predictors of HbA1c in both type 1 and type 2 diabetes include access to nurse educators, ethnic background and WHR. In type 2 diabetes, use of insulin was a significant predictor, while in type 1 diabetes, household income was a significant predictor. Socioeconomic status did not have a significant effect in type 2 diabetes. There were no significant differences in the glycaemic control in patients with different educational status. In conclusion, glycaemic control in big hospitals in Malaysia was poor, and was closely related to the availability of diabetes care facilities and ethnic group, rather than socioeconomic status.
    Matched MeSH terms: Linear Models
  20. Lim JM, Hong AG, Raman S, Shyamala N
    Ultrasound Obstet Gynecol, 2000 Feb;15(2):131-7.
    PMID: 10775996
    To determine whether racial differences affect the relationship between the fetal femur diaphysis length and the neonatal crown-heel length.
    Matched MeSH terms: Linear Models
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