Abstract: Hong Hoi Formation is a Middle Triassic deep marine succession presented in outcrops throughout the Lampang Basin of northern Thailand. The primary goal of this research is to diagnose the paleoenvironment, petrographic compositions, and sedimentary sources of the Hong Hoi Formation in Ban Huat, Ngao District. The Triassic Hong Hoi Formation is chosen because the outcrops are continuous and fossils are greatly exposed and abundant. Depositional environment is reconstructed through sedimentological studies along with facies analysis. The Hong Hoi Formation is petrographically divided into two major facies, they are: sandstones with mudstone interbeds, and mudstones or shale with sandstone interbeds. Sandstone beds are lithic arenite and lithic greywacke, volcanic lithic fragments are dominated. Sedimentary structures, paleocurrent data and lithofacies arrangement indicate that the formation deposited in a part of deep marine abyssal plain environment. The sedimentological and petrographic features suggest that during the deposition the Hong Hoi Formation received sediment supply from nearby volcanic arc. This suggested that the intensive volcanic activity within the Sukhothai Arc during the Middle Triassic is the main sediment source.
Abstract: The influence of physicochemical water quality
parameters on the abundance and diversity of caddisfly larvae was
studied in seven sampling stations in Mae Tao and Mae Ku
watersheds, Mae Sot District, Tak Province, northern Thailand. The
streams: MK2 and MK8 as reference site, and impacted streams
(MT1-MT5) were sampled bi-monthly during July 2011 to May
2012. A total of 4,584 individual of caddisfly larvae belonging to 10
family and 17 genera were found. The larvae of family
Hydropsychidae were the most abundance, followed by
Philopotamidae, Odontoceridae, and Leptoceridae, respectively. The
genus Cheumatopsyche, Hydropsyche, and Chimarra were the most
abundance genera in this study. Results of CCA ordination showed
the total dissolved solids, sulfate, water temperature, dissolved
oxygen and pH were the most important physicochemical factors to
affect distribution of caddisflies communities. Changes in the
caddisfly fauna may indicate changes in physicochemical factors
owing to agricultural pollution, urbanization, or other human
activities. Results revealed that the order Trichoptera, identified to
species or genus, can be potentially used to assess environmental
water quality status in freshwater ecosystems.
Abstract: This study aimed at developing a forecasting model on the number of Dengue Haemorrhagic Fever (DHF) incidence in Northern Thailand using time series analysis. We developed Seasonal Autoregressive Integrated Moving Average (SARIMA) models on the data collected between 2003-2006 and then validated the models using the data collected between January-September 2007. The results showed that the regressive forecast curves were consistent with the pattern of actual values. The most suitable model was the SARIMA(2,0,1)(0,2,0)12 model with a Akaike Information Criterion (AIC) of 12.2931 and a Mean Absolute Percent Error (MAPE) of 8.91713. The SARIMA(2,0,1)(0,2,0)12 model fitting was adequate for the data with the Portmanteau statistic Q20 = 8.98644 ( x20,95= 27.5871, P>0.05). This indicated that there was no significant autocorrelation between residuals at different lag times in the SARIMA(2,0,1)(0,2,0)12 model.