Estimation of soil erodibility in Peninsular Malaysia: A case study using multiple linear regression and artificial neural networks.

Soil erodibility (K) is an essential component in estimating soil loss indicating the soil's susceptibility to detach and transport. Data Computing and processing methods, such as artificial neural networks (ANNs) and multiple linear regression (MLR), have proven to be helpful in the development of predictive models for natural hazards. The present case study aims to assess the efficiency of MLR and ANN models to forecast soil erodibility in Peninsular Malaysia. A total of 103 samples were collected from various sites and K values were calculated using the Tew equation developed for Malaysian soil. From several extracted parameters, the outcomes of correlation and principal component analysis (PCA) revealed the influencing factors to be used in the development of ANN and MLR models. Based on the correlation and PCA results, two sets of influencing factors were employed to develop predictive models. Two MLR (MLR-1 and MLR-2) models and four neural networks (NN-1, NN-2, NN-3, and NN-4) optimized using Levenberg-Marquardt (LM) and scaled conjugate gradient (SCG) were developed and evaluated. The model performance validation was conducted using the coefficient of determination (R2), mean squared error (MSE), root mean squared error (RMSE), and Nash-Sutcliffe efficiency coefficient (NSE). The analysis showed that ANN models outperformed MLR models. The R2 values of 0.446 (MLR-1), 0.430 (MLR-2), 0.894 (NN-1), 0.855 (NN-2), 0.940 (NN-3), and 0.826 (NN-4); MSE values of 0.0000306 (MLR-1), 0.0000315 (MLR-2), 0.0000158 (NN-1), 0.0000261 (NN-2), 0.0000318 (NN-3), and 0.0000216 (NN-4) suggested the higher accuracy and lower modelling error of ANN models as compared with MLR. This study could provide an empirical basis and methodological support for K factor estimation in the region.

Use of complementary and alternative medicine among asthmatic patients in primary care clinics in Malaysia.

OBJECTIVES: This study aimed to determine the knowledge about asthma and the prevalence, disclosure and evaluation of the use of complementary and alternative medicine (CAM) among asthmatic patients. METHODS: This cross-sectional study was conducted on 95 patients diagnosed with asthma in a primary healthcare centre in Kuala Lumpur, Malaysia using a self-administered questionnaire. RESULTS: Ninety-five patients with a mean age of 47.06 years (±12.8) participated, the majority were female (66.7%), Malay (72.6%). The prevalence of ever-CAM use was 61.1%. The non-ever-CAM users' mean age was 51±13.9 years while the ever-CAM users' mean age was 44.5 ±11.5 years (P = 0.021). Sixty-three females (66.8%) used CAM compared to 14 males (43.8%) (P = 0.014). Thirty-six (62.1%) CAM users had not discussed use of CAM with their doctors. The main reason of non-disclosure was the doctor never asked (55.6%), and the main sources of information about CAM were family and relatives (46.6%). There was no significant difference between use of CAM and knowledge about asthma. The majority of asthmatic patients used rubs (39%), foods (16.9%) and herbs (16.9%). About 76% of asthmatic patients perceived CAM as good for their disease management. On linear multiple regression, Malay race (P = 0.026) and female gender (P = 0.006) were significant predictors of CAM use. CONCLUSION: Use of CAM among asthmatic patients is relatively high, particularly among females. The majority of asthmatic patients valued the use of CAM. Non-disclosure was high in this study. Health education of asthmatic patients about CAM is highly recommended.

Role of vitamin e on oxidative stress in smokers.

Cigarette smoke contains numerous oxygen free radicals that when inhaled, overwhelm antioxidant defenses and produce a condition of oxidative stress. This study investigated whether or not supplementation with vitamin E can affect the state of oxidative stress in healthy smokers. In this randomised double blind trial, 32 smokers received 200 mg of vitamin E or placebo daily for 8 weeks. All smokers in the vitamin E group completed the trial whilst only nine in the placebo group completed the trial. Plasma vitamin E concentrations increased significantly [P<0.02] in the vitamin E group. The release of malondialdehyde [MDA] from erythrocytes was not significantly different between the two groups at baseline and was clearly reduced [P<0.01] after 8 weeks of vitamin E supplementation. Vitamin E increased erythrocyte superoxide dismutase activity [P<0.02] and decreased gluthathione peroxidase activity [P<0.02]. No changes were detected in plasma MDA. We conclude that daily supplementation with 200 mg of vitamin E for 8 weeks improved the oxidative stress state in smokers.