706 research outputs found

    Hydrological study on subsurface temperature in Nagaoka plain

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    The subsurface temperature, one of the most easily measurable and universal elements in groundwater survey, is a conservative quantity in a groundwater flow system. In this study, seasonal and secular variations of subsurface temperature in an alluvial plain are obtained ...Thesis--University of Tsukuba, D.Sc.(A), no. 448, 1987. 3. 2

    Current Situation on Research Core in Marine Bio-production

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    The economic value of groundwater in Obama

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    AbstractStudy regionObama City has a population of 33,000 and is located in the central Wakasa district, in southwest Fukui Prefecture, Japan. Obama’s groundwater resources are supported by the Kitagawa (38km2) and Miniamigawa (17km2) river basins. Groundwater is used aboveground year round for commercial and domestic purposes and during winter months to melt snow. Submarine groundwater discharge along the coast supports a nearshore fishery in the region.Study focusResults from a choice-based analysis suggest that residents are willing to pay on average JPY 565 per month to maintain the drinking water function and aquatic resource function of groundwater in the Fukui region. However, the static approach is not appropriate for estimating the net present value of the resource, i.e., the discounted net benefit aggregated over time. We therefore develop and propose a dynamic framework capable of assessing tradeoffs between the various water uses as scarcity increases or decreases in the future.New hydrological insights for the regionMarginal willingness to pay for water in Obama is currently low because freshwater is abundant. We expect that future optimal water extraction patterns will depend most on trends in energy costs, climate change and demand growth

    Brain Activity Stimulated by Prism Adaptation Tasks Utilized for the Treatment of Unilateral Spatial Neglect: A Study with fNIRS

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    We investigated the neurological basis for efficacy of prism adaptation therapy, which is used for the treatment of poststroke unilateral spatial neglect (USN). Study subjects were 6 USN-positive (+), 6 USN-negative patients, and 6 healthy volunteer control subjects. USN was identified by the Behavioural Inattention Test (BIT). During the tasks, brain activity was assessed with fNIRS via changes in oxyHb concentration per unit length. There was no significant difference in the number of errors in the task between the 3 groups. However, in the USN(+) group there was a significantly greater reduction in oxyHb levels in the right parietal association cortex during the prism adaptation task than in the other 2 groups (P < 0.05). There was an immediate improvement in USN symptoms as well as a significant increase in oxyHb levels during the prism adaptation in the channels covering the right frontal and parietal lobes in 2 patients in the USN(+) group (P < 0.05). This result suggested that decreased activity in the right parietal association cortex, which is related to spatial perception, during the prism adaptation task and task-induced reorganization of the right frontal and parietal areas were involved in improvement in USN symptoms

    Groundwater flow system under a rapidly urbanizing coastal city as determined by hydrogeochemistry

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    In the Jakarta area (Indonesia), excessive groundwater pumping due to the rapidly increasing population has caused groundwater-related problems such as brackish water contamination in coastal areas and land subsidence. In this study, we adopted multiple hydrogeochemical techniques to demonstrate the groundwater flow system in the Jakarta area. Although almost all groundwater existing in the Jakarta basin is recharged at similar elevations, the water quality and residence time demonstrates a clear difference between the shallow and deep aquifers. Due to the rapid decrease in the groundwater potential in urban areas, we found that the seawater intrusion and the shallow and deep groundwaters are mixing, a conclusion confirmed by major ions, Br−:Cl− ratios, and chlorofluorocarbon (CFC)-12 analysis. Spring water and groundwater samples collected from the southern mountainside area show younger age characteristics with high concentrations of 14C and Ca–HCO3 type water chemistry. We estimated the residence times of these groundwaters within 45 years under piston flow conditions by tritium analysis. Also, these groundwater ages can be limited to 20–30 years with piston flow evaluated by CFCs. Moreover, due to the magnitude of the CFC-12 concentration, we can use a pseudo age indicator in this field study, because we found a positive correlation between the major type of water chemistry and the CFC-12 concentration

    In vitro production of L-cysteine using thermophilic enzymes

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    L-Cysteine (L-Cys) is a commercially important amino acid and widely used in food, pharmaceutical, and cosmetic industries. Commercial production of L-Cys has long been done by an acid-hydrolysis of human hair and animal feather, leading to the generation of a large quantity of hazardous wastes. Although several biotechnology companies have recently launched a fermentative production of L-Cys using engineered bacteria, these processes suffer from the low product titer mainly due to the cytotoxic effect of L-Cys. To provide an alternative approach for the commercial production of L-Cys, we aimed at the development of a non-fermentative, in vitro manufacturing system using thermophilic enzymes. In this system, enzymes from (hyper)thermophilic bacteria and archaea were assembled to construct an in vitro synthetic pathway for the one-pot conversion of glucose to L-Cys (Figure 1). By using experimentally optimized concentrations of enzymes, L-Cys could be produced at a rate of 0.9 g/L/h with a molar conversion yield of 25%. Please click Additional Files below to see the full abstract

    Discovery of hidden correlations in a local transaction database based on differences of correlations

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    Abstract. Given a transaction database as a global set of transactions and its sub-database regarded as a local one, we consider a pair of itemsets whose degrees of correlations are higher in the local database than in the global one. If they show high correlation in the local database, they are detectable by some search methods of previous studies. On the other hand, there exist another kind of paired itemsets such that they are not regarded as characteristic and cannot be found by the methods of previous studies but that their degrees of correlations become drastically higher by the conditioning to the local database. We pay much attention to the latter kind of paired itemsets, as such pairs of itemsets can be an implicit and hidden evidence showing that something particular to the local database occurs even though they are not yet realized as characteristic ones. From this viewpoint, we measure paired itemsets by a difference of two correlations before and after the conditioning to the local database, and define a notion of DC pairs whose degrees of differences of correlations are high. As the measure is non-monotonic, we present an algorithm, searching for DC pairs, with some new pruning rules for cutting off hopeless itemsets. We show by an experimental result that potentially significant DC pairs can be actually found for a given database and the algorithm successfully detects such DC pairs
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