This study presents the use of a wavelet-based time series model to forecast the daily average particulate matter with an aerodynamic diameter of less than 10 μm (PM10) in Peninsular Malaysia. The highlight of this study is the use of a discrete wavelet transform (DWT) in order to improve the forecast accuracy. The DWT was applied to convert the highly variable PM10 series into more stable approximations and details sub-series, and the ARIMA-GARCH time series models were developed for each sub-series. Two different forecast periods, one was during normal days, while the other was during haze episodes, were designed to justify the usefulness of DWT. The models' performance was evaluated by four indices, namely root mean square error, mean absolute percentage error, probability of detection and false alarm rate. The results showed that the model incorporated with DWT yielded more accurate forecasts than the conventional method without DWT for both the forecast periods, and the improvement was more prominent for the period during the haze episodes.
This is a review of 261 patients operated for 271 instances of mechanical intestinal obstruction over a 5-year period in a developing country in the tropics. The pattern of intestinal obstruction in Chinese is similar to that in Caucasians, where adhesions account for the largest number of cases. The occurrence in Malays, Indians, Pakistanis and Ceylonese is similar to that in other developing communities where external hernia is commonest while adhesive or tumour obstruction is rare; however, these racial groups do not exhibit the high incidence of intussusception and volvulus found in Africa and India. The operative mortality was 13-9 per cent, which is comparable to that in Western series. The major adverse factors in intestinal obstruction, i.e. extremes of age, associated disease, gangrenous bowel, large bowel obstruction and malignancy, were confirmed. Fluid and electrolyte imbalance was frequent, as in other tropical series, but with intensive preoperative correction it was not an important adverse factor.
The clinical features and pathology of 17 patients with gastrointestinal lymphoma are reviewed. The small intestine was the site most commonly involved. Emergency presentation was usual: 11 of the 17 patients presented as acute abdomen or gastrointestinal haemorrhage. The frequency of gastrointestinal lymphoma to carcinoma in the Chinese and Indians was comparable to that in the West but a higher frequency was found in the Malays and Orang
Asli.
Histocompatibility locus A typing of 43 Malaysian Chinese and 51 Hong Kong Chinese patients with nasopharyngeal carcinoma (NPC) confirmed the association between the occurrence of A2-Sin 2 and the increased risk for NPC that was previously demonstrated in Singapore Chinese. The results support the previous interpretation that the histocompatibility locus A genotype of importance in NPC predisposition is the A2-Sin 2 haplotype. The histocompatibility locus A-linked, genetically determined NPC risk is common to Asian Chinese from at least three geographic locations.