Modeling of the Fate and Agrochemical Movement Under Controlled Water Table Environment

The study was undertaken to investigate the effect of water table management practices on the environmental transport and fate of agrochemicals. A laboratory based study using disturbed sand soil columns was conducted to investigate the transport and fate of nitrate (NO~), a commonly used agricultural chemical, to the underground environment as effected by controlled water table depths. Three controlled water table depths set as 0.25m, 0.50m, and 0.75m from the surface and free drainage treatment (no controlled water table depth) were used. A simple statistical model based on mUltiple linear regression analysis was developed using experimental data to simulate reduction and transport of nitrate in soil columns under different water table depths. The regression model was developed from selected physical variables including water table depth from the surface, time, and saturated depth. An imperial equation was obtained from the experimental data with a correlation coefficient of R2 =0.83. The performance of this equation was tested using experimental data and it was found that the output from this equation is acceptable and satisfactory.According to the simulated and observed results, it was clearly shown that the water table depth affects the characteristics of transport nitrate. In addition significant reduction in nitrate concentration was achieved through different water table treatments. The results suggest it is possible to promote biological and chemical degradation to reduce nitrate transport by controlling water table depths

Ankle fractures: the operative outcome

Ankle fractures are commonly seen in orthopaedic practice. This retrospective study of patients with ankle fractures who underwent surgical treatment in our institution from January 2000 to December 2003 was undertaken to analyze the common causes and patterns of ankle fractures; and the functional outcome of operative treatment for these fractures. Eighty patients were identified and reviewed. There were 65 male (81.3%) and 15 female patients (18.7%) with age ranging from 13 to 71 years old (mean, 32.3y). Common causes of ankle fractures were trauma (especially motor vehicle accidents), sports injuries and the osteoporotic bones in the elderly. Weber C (64.0%) was the most common pattern of fracture at presentation. The most common operative treatment for ankle fractures was open reduction and internal fixation (73 patients, 91.2%). Excellent and good outcomes were achieved in 93.8% of cases when measured using the Olerud and Molander scoring system for foot and ankle. In conclusion, operative treatment for ankle fractures restores sufficient stability and allowed mobility of the ankle joint

Energy-absorption buildup factors and specific absorbed fractions of energy for bioactive glasses

In the present work, effective atomic numbers Zeff, energy-absorption buildup factors EABF and specific absorbed fractions of energy (Φ) for different bioactive glasses have been calculated in the present work. Geometric-Progression (G-P) fitting method was used for computation of EABF. The computed EABF is used to estimate the values of Φ. It is shown that the EABF and Φ are dependent on Zeff and mean free path. In addition, EABF and Φ were the largest for S4 and S7.The results in this work could be useful in choosing a suitable type of these glasses which in turn are able to resist possible radiation damages at human body and to determine the thickness and shape of the bioactive glasses needed

Carotenoid composition and antioxidant potential of Eucheuma denticulatum, Sargassum polycystum and Caulerpa lentillifera

Three species of Malaysian edible seaweed (Eucheuma denticulatum, Sargassum polycystum and Caulerpa lentillifera) were analyzed for their carotenoid composition using a combination of high-performance thin layer chromatography (HPTLC) and ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS), while the antioxidant capacities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. The HPTLC analysis exhibited a distinct carotenoid pattern among the three seaweed groups. The UHPLC-ESI-MS/MS analysis showed fucoxanthin as the major carotenoid present in S. polycystum while lutein and zeaxanthin in E. denticulatum. For C. lentillifera, β-carotene and canthaxanthin were the major carotenoids. Some of the carotenoids, such as rubixanthin, dinoxanthin, diatoxanthin and antheraxanthin, were also tentatively detected in E. denticulatum and S. polycystum. For antioxidant activity, S. polycystum (20 %) and E. denticulatum (1128 μmol TE/g) showed the highest activity in the DPPH and ORAC assays, respectively. The findings suggest the three edible varieties of seaweeds may provide a good dietary source with a potential to reduce antioxidative stress

Variation of growth and proximate composition in Portunus pelagicus juveniles fed with selected feeds in recirculating aquaculture system (RAS)

Aim: The experiment was conducted to determine the suitability of using scad fish, Acetes shrimp and common squid for the direct and indirect application as diets for the juvenile rearing of the blue swimming crab Portunus pelagicus. Methodology: A total of 54 crab juveniles with an initial weight of 2.46 ±0.94 g were randomly stocked in triplicate at 6 crabs per 60 l tank (0.26 m²) experimental units and fed twice daily with three different types of feed namely scad fish, squid tissue and frozenAcetesshrimp foraperiodof31days. Results: At the end of the trail, ammonia and nitrite-nitrogen compound were significantly higher in Acetes shrimp fed group. It is found that final body weight (g) of P. pelagicus was significantly higher when fed with squid, however no significant differences were noticed between scad fish and Acetes shrimp fed groups. The whole body proximate composition was similar in all the diet fed individuals except the level of lipid which was higher in squid compared to scad fish and Acetes shrimp. Significantly (p<0.05) better food conversion ratio (FCR) was observed in juvenile crab fed with squid even though scad fish possessed the highest crude protein of 83.33%. Interpretation: Overall, the results suggested that squid meal could be recommended for P. pelagicus juvenile culture. Hence, squid meal may be incorporated in crab artificial diet as protein source to attain better survival and growth

Population parameters of Rastrelliger kanagurta (Cuvier, 1816) in the Marudu Bay, Sabah, Malaysia

An investigation of the population parameters of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) in the Marudu Bay, Sabah, Malaysia was carried out from January to September 2013. The relationship between total length and body weight was estimated as W=0.006TL3.215 or Log W=3.215LogTL – 2.22 (R2=0.946). Monthly length frequency data of R. kanagurta were analyzed by FiSAT software to evaluate the mortality rates and its exploitation level. Asymptotic length (Lµ) and growth co-efficient (K) were estimated at 27.83 cm and 1.50 yr-1, respectively. The growth performance index (φ') was calculated as 3.07. Total mortality (Z), natural mortality (M) and fishing mortality (F) was calculated at 4.44 yr-1, 2.46 yr-1 and 1.98 yr-1, respectively. Exploitation level (E) of R. kanagurta was found to be 0.45. The exploitation level was below the optimum level of exploitation (E=0.50). It is revealed that the stock of R. kanagurta was found to be still under exploited in Marudu Bay

Influence of habitat structure and environmental variables on larval fish assemblage in the Johor Strait, Malaysia

Our previous study demonstrated that among different habitat sites (mangrove, estuary, river, seagrass and Open Sea) in Johor Strait, Malaysia, seagrass showed highest family diversity and abundance of larval fish. However, it is unclear whether this was due to difference in habitat complexity or water quality parameters. To test this, larval fish were collected by using a bongo net equipped with a flow meter by subsurface horizontal towing from different habitats in Johor Strait between October 2007 and September 2008. Various physico-chemical parameters were measured and then examined for any relationship to fish larvae diversity and abundance. Among the 24 families identified from the sites, seven families (Blenniidae, Clupeidae, Mullidae, Nemipteridae, Syngnathidae, Terapontidae and Uranoscopeidae) were significantly correlated with the tested waters quality parameters. Salinity showed a positive and negative significant correlation with Clupeidae (p < 0.01) and Uranoscopeidae (p < 0.05), respectively. Terapontidae was significantly correlated with dissolved oxygen (p < 0.01), while both Mullidae and Syngnathidae were significantly correlated with pH (p < 0.05). However, a canonical correspondence analysis test indicated weak overall correlation (36.4%) between larval assemblage and in the seagrass-mangrove ecosystem of Johor Strait, Malaysia. This likely indicates that habitat structure was more important in determining larval abundance (highest in the seagrass habitat) as compared to water quality at the tested sites. This study emphasizes the need to conserve seagrass beds as important nursery grounds for various fish larvae to ensure adequate recruitment and ultimately sustainable fisheries management

Optimization of equitable irrigation water delivery for a large-scale rice irrigation scheme

Equitable water allocation is essential in an irrigation scheme for obtaining potential crop yields from the entire scheme, especially when water supply is inadequate. An optimization model achieved this goal by coupling an optimal water allocation model with available water supply and irrigation water demand for a river-fed rice irrigation system in Malaysia. This model consists of a paddy field water balance module and an optimization module. The outputs from the module are daily irrigation demand and surface runoff, if there is any. The optimization module consists of an objective function, which minimizes water shortage across the scheme area while maintaining equity in water allocation. This model performs optimization subject to several system constraints, and the decision variable of the model is daily releases or supply to the tertiary canals. Performance of this model remained unaffected under different water supply conditions, and the optimization model reliably examined the effects of alternate water allocation and management rules with field information. It improves efficiency and equity in water allocation with respect to crop growth stages and water shortages rather than simply cutting irrigation supply on a proportional basis to overcome water shortages

Bees algorithm enhanced with Nelder and Mead method for numerical function optimisation

The Bees Algorithm is a population-based optimisation algorithm inspired by the food foraging behaviour of honey bees. Over the years, this algorithm has been successfully applied to many optimisation problems. In order to enhance its accuracy and convergence rate, it is proposed to employ the Nelder and Mead (NM) method to implement the local search phase of the algorithm. The enhanced algorithm uses directional information to direct recruited bees towards better fitness positions within the local search area. The performance of the proposed algorithm was tested on a set of seventeen well-known benchmark functions. Numerical results show that the proposed algorithm generally performs better than the standard Bees Algorithm

Length-weight and length-length relationship models of four carangid fishes from the Matang Mangrove Estuaries, Perak, Malaysia

Four species of Carangid fishes from Matang Mangrove Estuaries, Perak, Peninsular Malaysia were selected for the study of length-weight relationships (LWR) and length-length relationships (LLR). A total of 308 individuals were collected from September 2015 to August 2016 by push net (mesh sizes ranges from 2.5 to 5.0 cm). Overall, the growth coefficient (b) values were 2.005, 3.014, 3.452 and 3.194 for Carangoides malabricus, Atule mate, Decapterus macrosoma and Selaroides leptolepis, respectively. Growth coefficient of three species (A. mate, D. macrosoma and S. leptolepis) in the present study were within expected range of 2.5 - 3.5 and this indicated that those species have normal growth pattern. This research serves as the first record of LWR and LLR data for four species of Carangid fishes in the Matang Mangrove Estuaries and surrounding ecosystem, Malaysia