Superior Performance in Skilled Golfers Characterized by Dynamic Neuromotor Processes Related to Attentional Focus.

The meshed control theory assumes that cognitive control and automatic processes work together in the natural attention of experts for superior performance. However, the methods adopted by previous studies limit their capacity to provide in-depth information on the neuromotor processes. This experiment tested the theory with an alternative approach. Twelve skilled golfers were recruited to perform a putting task under three conditions: (1) normal condition, with no focus instruction (NC), (2) external focus of attention condition (EC), and (3) internal focus of attention condition (IC). Four blocks of 10 putts each were performed under each condition. The putting success rate and accuracy were measured and electroencephalographies (EEGs) were recorded. The behavioral results showed that the NC produced a higher putting success rate and accuracy than the EC and IC. The EEG data showed that the skilled golfers' attentional processes in the NC initially resembled those in the EC and then moved toward those in the IC just before putting. This indicates a switch from more automatic processes to cognitive control processes while preparing to putt. The findings offer support for the meshed control theory and indicate the dynamic nature of neuromotor processes for the superior performance of athletes in challenging situations.

Management of groundwater in farmed pond area using risk-based regulation.

Blackfoot disease (BFD) had occurred seriously in the Yichu, Hsuehchia, Putai, and Peimen townships of Chia-Nan District of Taiwan in the early days. These four townships are the districts of fishpond cultivation domestically in Taiwan. Groundwater becomes the main water supply because of short income in surface water. The problems of over pumping in groundwater may not only result in land subsidence and seawater intrusion but also be harmful to the health of human giving rise to the bioaccumulation via food chain in groundwater with arsenic (As). This research uses sequential indicator simulation (SIS) to characterize the spatial arsenic distribution in groundwater in the four townships. Risk assessment is applied to explore the dilution ratio (DR) of groundwater utilization, which is defined as the ratio showing the volume of groundwater utilization compared to pond water, for fish farming in the range of target cancer risk (TR) especially on the magnitude of 10(-4)~10(-6). Our study results reveal that the 50th percentile of groundwater DRs served as a regulation standard can be used to perform fish farm groundwater management for a TR of 10(-6). For a TR of 5 × 10(-6), we suggest using the 75th percentile of DR for groundwater management. For a TR of 10(-5), we suggest using the 95th percentile of the DR standard for performing groundwater management in fish farm areas. For the TR of exceeding 5 × 10(-5), we do not suggest establishing groundwater management standards under these risk standards. Based on the research results, we suggest that establishing a TR at 10(-5) and using the 95th percentile of DR are best for groundwater management in fish farm areas.

Assessing the characteristics of groundwater quality of arsenic contaminated aquifers in the blackfoot disease endemic area.

Redox couples approach and multivariate statistical techniques, including factor analysis, cluster analysis and discriminant analysis, were applied to evaluate and to interpret the complex groundwater quality in the blackfoot disease endemic area, Taiwan. Most groundwater samples were characterized as Na-Ca-HCO(3) with HCO(3)(-) as the dominant anion. Total arsenic (As) concentration, predominantly as As(3+), ranged from <1.0 to 562.7 µg/L. The patterns of measured reducing potential were consistent with those values calculated from As couple, revealing the in situ environment enhanced the accumulation of As concentration in the groundwater. Factor analysis proposed a four-factor model, comprising salination, reductive dissolution of Fe/Mn oxyhydroxides, As reduction and chemical potential factor, and explained 89.94% of total variance in groundwater. Furthermore, two factors, reductive dissolution of Fe/Mn oxyhydroxides and As reduction, suggested that the decoupled reductive processes accounted for high As concentration in this area. Cluster analysis was adopted to spatially categorize the sampled wells into three main clusters and characterized by the factor scores of the four-factor model. Two-parameter (pH and Eh) model derived from discriminant analysis can be used for preliminary assessment to determine whether the As concentration exceeds 10 µg/L with simple field measurements in this area.

An integrated GIS-based approach in assessing carcinogenic risks via food-chain exposure in arsenic-affected groundwater areas.

This study presented an integrated GIS-based approach for assessing potential carcinogenic risks via food-chain exposure of ingesting inorganic arsenic (As) in aquacultural tilapia, milkfish, mullet, and clam in the As-affected groundwater areas. To integrate spatial information, geographic information system (GIS) was adopted to combine polygon-shaped features of aquacultural species with cell-shaped features of As contamination in groundwater. Owing to sparse measured data, Monte Carlo simulation and sequential indicator simulation were used to characterize the uncertainty of assessed parameters. Target cancer risks (TRs) of ingesting As contents at fish ponds were spatially mapped to assess potential risks to human health. The analyzed results reveal that clam farmed at the western coastal ponds and milkfish farmed at the southwestern coastal ponds have high risks to human health, whereas tilapia cultivated mainly at the inland ponds only has high risks at the 95th percentile of TR. Mullet in general has low risks to human health. Moreover, to decrease risks, this study suggests reducing the use of As-affected groundwater at clam and milkfish ponds due to high bioconcentration factor (BCF) of clam and inorganic As accumulation ratio of milkfish. The integrated GIS-based approach can provide fishery administrators with an effective management strategy at specific fish ponds with high risks to human health.

Sorptive removal of tetracycline from water by palygorskite.

Extensive use of pharmaceuticals and growth hormone in farm animal and live stocks has resulted in their frequent detection in soils, groundwater, and wastewater. The fate and transport of these compounds are strongly affected by their sorptive behavior to the soil minerals and humic materials. In this research, we conducted the sorption of tetracycline (TC), a common antibiotic, on palygorskite (PFL-1), a fibrous clay mineral of high surface area and high sorptivity towards organic compounds. The results showed that the sorption capacity of TC on PFL-1 was as high as 210 mmol/kg at pH 8.7. The sorption was relatively fast and reached equilibrium in 2h. Solution pH and ionic strength had significant effects on TC sorption. The sorption of TC by palygorskite is endothermic and the free energy of sorption is in the range of -10 to -30 kJ/mol, suggesting a strong physical sorption. The X-ray diffraction patterns before and after TC sorption revealed no changes in d-spacing and intensity under different pH and initial TC concentrations, indicating that the sorbed TC molecules are on the external surface of the mineral in contrast to intercalation of TC into swelling clays, such as montmorillonite. The small positive value of entropy change suggested that TC molecules are in disordered arrangement on palygorskite surfaces. Surface sorption of TC on PFL-1 is further supported by the derivative of gravimetric analysis and by the calculation of the amount of TC sorption normalized to the surface area. The results suggest that palygorskite could be a good candidate to remove TC from wastewater containing higher amounts of TC.

Spatiotemporal distribution of arsenic species of oysters (Crassostrea gigas) in the coastal area of southwestern Taiwan.

This study investigated total arsenic (As) and As species contents of oysters (Crassostrea gigas) in different production areas, seasons and sea locations on the southwestern coast of Taiwan. Analytical results indicate that contents of total As, arsenite, arsenate, dimethylarsinic acid, monomethylarsonic acid and arsenobetaine in oysters are 9.90+/-3.68, 0.091+/-0.104, 0.033+/-0.038, 0.529+/-0.284, 0.037+/-0.046 and 3.94+/-1.33 mg/g (dry wt), respectively. A ratio of inorganic As concentrations to total As concentrations is 1.26%. Total As contents of oysters cultured in the outer sea are statistically significantly lower than those of oysters cultured in the inner sea. The total As contents of oysters is the highest in Putai, where the blackfoot disease prevails. The low As contents in oysters is attributed to the low temperature in winter, which slows the metabolism of oysters. A maximum value is 33.37 microg/g (dry) in Putai in spring, because a considerable amount of aquacultural waste water with high As contents is discharged into adjacent drainage channels and rivers there during that season.

Bioaccumulation of arsenic compounds in aquacultural clams (Meretrix lusoria) and assessment of potential carcinogenic risks to human health by ingestion.

This study surveyed the total arsenic (As) and As species contents in clams (Meretrix lusoria) farmed in areas of hyperendemic blackfoot disease (BFD) in southwestern Taiwan. Total As and As species in sediment and pond water were also analyzed to examine the bioaccumulation of As in clams in their exposure environment. Moreover, potential carcinogenic risks associated with the ingestion of As in aquacultural clams were evaluated probabilistically. The average total As contents in medium-sized and small clams were 7.62 and 10.71 microg/g (dry wt), respectively. The content of the As species in this study was approximately 61% of the total As content. The other unquantified As species are possibly arsenocholine, arsenosugar and arsenolipid. The average ratios of inorganic As contents to total As contents in clams ranged from 12.3% to 14.0% which are much higher than that found in the farmed oyster (Crassostrea gigas), indicating that humans may expose to larger quantities of inorganic As by ingesting the same amount of clam as oyster. Using different ingestion rates derived by the average consumption method and the questionnaire method, the estimated risks to human health associated with consuming clams from the BFD area ranging from slightly to largely exceed the standard target risk. Based on the estimation of the TR model, a 0.18g/day-person of the safe ingestion rate of clams in the BFD region is recommended.

Spatial analysis of potential carcinogenic risks associated with ingesting arsenic in aquacultural tilapia (Oreochromis mossambicus) in blackfoot disease hyperendemic areas.

This work analyzed spatially potential carcinogenic risks associated with ingesting arsenic (As) contents in aquacultural tilapia (Oreochromis mossambicus) in coastal regions of southwestern Taiwan, where the blackfoot disease prevails. Sequential indicator simulation (SIS) was used to reproduce As exposure distributions in groundwater based on their three-dimensional variability. A target cancer risk (TR) associated with ingesting As in aquacultural tilapia was calculated to evaluate the potential risk to human health. Owing to sparse measured data, Monte Carlo simulation and SIS properly accounted for the uncertainty of assessed parameters. The probabilistic risk assessment formulated suitable strategies under various remedial stages. Aquacultural regions with high risks were mapped to elucidate the safety of groundwater use at different depths. Many TRs determined from the risks at the 75th and 95th percentiles exceed one millionth in the regions, indicating that ingesting tilapia farmed in the highly As-polluted regions poses potential cancer threats to human health. The 75th percentile of TR is considered in formulating a remedial strategy for the aquacultural use of groundwater in the preliminary stage. Additionally, this study suggests reducing the use of groundwater in aquaculture or changing the depths from which groundwater is withdrawn in the areas with high risks of cancer.

Evaluation of the ability of an artificial neural network model to assess the variation of groundwater quality in an area of blackfoot disease in Taiwan.

The back-propagation (BP) artificial neural network (ANN) is applied to forecast the variation of the quality of groundwater in the blackfoot disease area in Taiwan. Three types of BP ANN models were established to evaluate their learning performance. Model A included five concentration parameters as input variables for seawater intrusion and three concentration parameters as input variables for arsenic pollutant, respectively, whereas models B and C used only one concentration parameter for each. Furthermore, model C used seasonal data from two seasons to train the ANN, whereas models A and C used only data from one season. The results indicate that model C outperforms models A and B. Model C can describe complex variation of groundwater quality and be used to perform reliable forecasting. Moreover, the number of hidden nodes does not significantly influence the performance of the ANN model in training or testing.

Arsenic species contents at aquaculture farm and in farmed mouthbreeder (Oreochromis mossambicus) in blackfoot disease hyperendemic areas.

A study was conducted to measure the arsenic species in farmed mouthbreeder (Oreochromis mossambicus) and culture ponds in water in blackfoot disease (BFD) hyperendemic areas in Taiwan. The relationships between arsenic species of aquaculture ponds and farmed fish were also explored. Biota samples were extracted with methanol/water (1/1, v/v) using a Soxhlet extraction apparatus. The concentrations of arsenite As (III), arsenate As (V), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) of extracts were measured by high-performance liquid chromatography (HPLC) linked to a hydride generator and atomic absorption spectrometry (HG-AAS). Moreover, arsenobetaine (AB) was analyzed by HPLC linked to ultra violet (UV) and HG-AAS. Concentrations of arsenic species were determined in 68 mouthbreeder (O. mossambicus) samples and 21 culture ponds from Putai and Yichu Townships of Chiayi County and Hsuehchia and Peimen Townships of Tainan County. The mean arsenic levels of culture ponds in Putai, Yichu, Hsuehchia, and Peimen were 75.8, 15.1, 14.4, and 221.0 microg/l, respectively. The water of culture ponds was dominated by As (V). The inorganic arsenic percentage of fish (7.4%) was higher than that reported by other seafood surveys. Except for the MMA and As (III) levels, As (V), DMA, AB, and total arsenic levels in fish significantly increased with inorganic and total arsenic concentrations of the pond water. Inorganic arsenic species are more toxic than methyl arsenic species. Therefore the effect of inorganic arsenic species might result in a greater number of adverse health effects to the general public. It is of importance to evaluate the inorganic arsenic levels of farmed seafood in arsenic-contaminated areas.

Application of factor analysis in the assessment of groundwater quality in a blackfoot disease area in Taiwan.

Factor analysis is applied to 28 groundwater samples collected from wells in the coastal blackfoot disease area of Yun-Lin, Taiwan. Correlations among 13 hydrochemical parameters are statistically examined. A two-factor model is suggested and explains over 77.8% of the total groundwater quality variation. Factor 1 (seawater salinization) includes concentrations of EC, TDS, Cl(-), SO(4)(2-), Na(+), K(+) and Mg(2+), and Factor 2 (arsenic pollutant) includes concentrations of Alk, TOC and arsenic. Maps are drawn to show the geographical distribution of the factors. These maps delineate high salinity and arsenic concentrations. The geographical distribution of the factor scores at individual wells does not reveal the sources of the constituents, which are instead, deduced from geological and hydrological evidence. The areas of high seawater salinization and arsenic pollution correspond well to the groundwater over-pumping area. Over-pumping of the local groundwater causes land subsidence and gradual salinization by seawater. The over-pumping also introduces excess dissolved oxygen that oxidizes the immobile minerals, releases arsenic by reductive dissolution of arsenic-rich iron oxyhydroxides and increases the arsenic concentration in water. The over-extraction of groundwater is the major cause of groundwater salinization and arsenic pollution in the coastal area of Yun-Lin, Taiwan.