Optimization of a multiple reservoir system operation using a combination of genetic algorithm and discrete differential dynamic programming: a case study in Mae Klong system, Thailand

A combination of genetic algorithm and discrete differential dynamic programming approach (called GA-DDDP) is proposed and developed to optimize the operation of the multiple reservoir system. The demonstration is carried out through application to the Mae Klong system in Thailand. The objective of optimization is to obtain the optimal operating policies by minimizing the total irrigation deficits during a critical drought year. The performance of the proposed algorithm is compared with the modified genetic algorithm. The results show that the proposed GA-DDDP provides optimal solutions, converging into the same fitness values within a short time. The GA is able to produce satisfactory results that are very close to those obtained from GA-DDDP but required alot more computation time to obtain the precise results. The difficulties in selecting optimal parameters of GA as well as finding a feasible initial trial trajectory of DDDP are significant problems and time-consuming. The significant advantage obtained from GA-DDDP is saving of computational resource as GA-DDDP requires no need for optimizing parameters and deriving feasible initial trial trajectories. Because DDDP is a part of GA-DDDP, the good performance of GA-DDDP is obtained when applied to a small system where numbers of discretizations and variables have no influence to the dimensionality problem of DDDP.     

Fluctuation of NO3-N in groundwater of the reservoir of the Sunagawa Subsurface Dam, Miyako Island, Japan

The Japanese government started to construct two subsurface dams on Miyako Island in 1988, and the project was completed in 2001. Before the construction of the dams, the NO₃-N concentration of groundwater on the island was about 10 mg/l, the upper limit for drinking water in Japan, owing to the application of fertilizer to sugarcane fields. Predicting the effect of these subsurface dams on the groundwater environment was difficult because they were probably the first mega-subsurface dams in the world. We measured the NO₃-N concentration in the groundwater at observation wells before and after construction of the Sunagawa Dam and after the groundwater began to be used. We also measured the NO₃-N concentration monthly at a typical observation well in the catchment over a period 14 years to evaluate the environmental impact of construction of the dam. The highest NO₃-N concentrations were downstream before completion of the subsurface dam, and a high NO₃-N concentration zone remained around the cut-off wall after its completion, but this high-concentration zone disappeared and the distribution of NO₃-N became uniform after pumping of the groundwater began. Overall, the NO₃-N concentration decreased gradually. These results show that the groundwater quality did not deteriorate as a result of the construction of the Sunagawa Subsurface Dam.     

A cell preparation of Enterococcus faecalis strain EC-12 stimulates the luminal immunoglobulin A secretion in juvenile calves

The immune system in juvenile calves is immature, so calves are susceptible to several diarrheal and respiratory diseases. Oral administration of lactic acid bacteria (LAB) is known to improve the growth performance and prevent diarrheal and respiratory diseases by stimulating the immune system in juvenile calves. Most of the immunostimulation by LAB is achieved by their cell wall components, and therefore we evaluated the immunostimulation of the cell preparation of Enterococcus faecalis strain EC-12 (EC-12) in juvenile calves in a clinical field. Twenty-nine 1-week old calves were used. Fourteen calves were administered 0.2% (w/w) of an EC-12 preparation that supplemented a milk replacer, and other calves were not supplemented. Feces and serum was collected at day 0, 7 and 49 after the administration to measure the IgA and IgG concentration. The fecal IgA concentration was increased by EC-12 administration at day 49, and the serum IgA concentration was also increased at day 7. These results suggested that oral administration of EC-12 in juvenile calves might have an immunostimulatory effect and provide earlier recovery of IgA levels in mucosal immunity.     

Species-specific thermal denaturation pattern of fish myosin when heated as myofibrils as studied by myosin subfragment-1 and rod denaturation rates

Thermal denaturation of myofibrils from various species of fish was investigated by measuring ATPase inactivation, myosin aggregation, myosin subfragment-1 (S-1) and rod denaturation rates as studied by chymotryptic digestion. Decrease in monomeric myosin (myosin aggregation) was always faster than the ATPase inactivation for all myofibrils tested. The relative denaturation rate of rod to that of S-1 differed from species to species. Preceded denaturation of rod was observed with some species, and the opposite was true with other species. The denaturation pattern was explained by the different magnitude of S-1 stabilization by F-actin in myofibrils at low salt medium. Myofibrils which receive a great stabilization by F-actin as studied by ATPase inactivation showed the preceded rod denaturation pattern, and vice versa. S-1 portion, not F-actin, determined the different stabilization of S-1 by F-actin in myofibrils.     

Occurrence and distribution during the post-settlement stage of two Choerodon species in shallow waters around Ishigaki Island, southern Japan

The recruitment patterns of black-spot tuskfish Choerodon schoenleinii were compared with those of orange-dotted tuskfish (OT) C. ancholago. Individuals at the settlement and juvenile stages were collected using a push net in the intertidal zone and a seine net in seagrass beds. Relative values of standard length to total length (TL) for the two Choerodon species indicated an inflection point at approximately 10?C20?mm TL, suggesting that both species complete metamorphosis at a similar size. However, their temporal and spatial occurrence patterns were distinct. Newly settled individuals (postflexion stage) of black-spot tuskfish were collected mainly within foliage of Sargassum plants of the intertidal zone around March?CApril, while those of OT occurred in both the intertidal zone and seagrass beds mainly in May and June. In seagrass beds, the abundances of both species increased from May or June; however, the TL of black-spot tuskfish was bigger than that of OT. Therefore, black-spot tuskfish progressively migrate to seagrass beds after settling and completing metamorphosis in the intertidal zone, indicating that they utilize two different habitats as nursery grounds. Early spawning and migration from the intertidal zone by this species contributed to the occurrence of relatively large individuals in seagrass beds.     

Complete mitochondrial genome sequence of Japanese cockle Fulvia mutica (Cardiidae)

The complete mitochondrial genome (mt-genome) sequence of Fulvia mutica (Veneroida; Cardiidae) was determined. The genome is 19,110 bp in size and contains 42 genes, including the ATP synthase subunit 8 gene (atp8). All genes are on the same strand, as in other marine bivalves. It is extremely different in gene arrangement and size from that of Acanthocardia tuberculata, the only species belonging to Cardiidae with complete genome sequence data. The presence of putative atp8 genes in two additional reported bivalve species, A. tuberculata and Sinonovacula constricta was also inferred by revising their deposited sequence data. It was suggested that atp8 genes of heterodont bivalves could be translated to 37–39 amino acid sequences highly conserved within families, excluding Hiatella arctica with 53 amino acids. The mt-genome of F. mutica also contains two large duplicated regions related to different sequence motifs. One of the regions consists of five nearly identical copies of the 154 bp motif that includes a transfer RNA gene for cysteine. This region exhibited polymorphism in the number of repeats among individuals, suggesting the existence of a variable number of tandem repeats, which was expected to provide valuable information for developing useful genetic markers for phylogenetic study and population genetics.     

Otolith development and daily increment formation in laboratory-reared larval and juvenile black-spot tuskfish <Emphasis Type="Italic">Choerodon schoenleinii</Emphasis>

Microstructures of lapilli were examined for reared larvae and juveniles of black-spot tuskfish Choerodon schoenleinii. Lapilli of larvae at 1 day after hatching have one diffuse and obscure ring with an otolith radius of 4.3 ± 0.50 μm (mean ± SD, N = 8). The slope and intercept of the regression between the number of days after hatching and increment counts did not differ significantly from one and zero, respectively, indicating that lapillus increments were formed on a daily basis after hatching. There was an ontogenetic shift in the relative values of somatic and otolith growth, which corresponded to the transition from pelagic larvae to settlement stage. Simultaneously, the daily increment width reached the maximum value. These findings suggest that age at maximum value of increment width can be used as an indicator of the planktonic larval duration while settlement mark is not found. Since ontogenetic shift in the relationship between otolith radius and body size was observed, back-calculation of somatic growth in black-spot tuskfish using the otolith radius during the early life stages should be analyzed with caution, and the method requires further validation.     

Novel reovirus isolation from an Ostrich (Struthio camelus) in Japan

An orthoreovirus was isolated from an Ostrich (Struthio camelus) and rapidly identified as orthoreovirus by the rapid determination of viral RNA sequences (RDV) system and electron microscopy. Phylogenetic analysis of the sigma A protein indicated that the isolate belonged to avian species and was closely related to chicken orthoreovirus strain 138. The results of the present study indicated that an ostrich orthoreovirus is slight different from other chicken orthoreoviruses and provided evidence of diversity among avian orthoreoviruses. To our knowledge, this is the first genetic report of an orthoreovirus isolated from an ostrich.