An objective of this study was to analyze which flow fields of a river were preferred by children for their water activities through a field research at the middle of the Doki River located in Manno Town, Kagawa Prefecture. In order to analyze the children' preferences on each age group for flow fields to play in water, the Jacobs' Indices were calculated by flow fields played by children classified by water depth and velocity. The following findings are obtained; 1) In case of under six years old, flow fields that water depth was less than 30 cm and water velocity was less than 0.1 cm/s were selected specifically for their activities. 2) Over 7 years old children come to prefer deeper and faster flow fields.
We conducted a phylogenetic analysis of the cytochrome b gene sequences (1,131-bp) in mitochondrial DNA, to elucidate genetic variation and diversity of the loach Misgurnus anguillicaudatus population in Japan. There were 147 haplotypes that were identified from 444 specimens collected from 123 sites. The phylogenetic tree based on the maximum parsimony method indicated three clades (A, B and C). Clade A resembled genetically the European loach M. fossilis, and the haplotypes were distributed from the North Kanto region northward. Clade B was closely related to the Chinese loach M. anguillicaudatus, and the haplotypes were distributed over the South Tohoku region westward. Clade C that composed of seven subclades seemed to be endemic to Japan, and the haplotypes of these subclades indicated regional or nationwide distribution. Distribution of Clade A and B in Japan appeared to derive from not only artificial release of individuals imported recently from China or Korea, but also diastrophism related to formation processes of the Japanese Islands. Also the estimated divergence time for evolutionary separations between clades was from the upper Miocene to the lower Pliocene (7.4 to 3.8 mya).
A real-time flood forecasting system was developed for runoff forecasting at several water gauging points. The system is based on a flood runoff model composed of the upstream part and the downstream part models which are respectively simulating runoff for the upstream and downstream parts of the objective basin. The upstream part model is a lumped rainfall-runoff model, and the downstream part model consists of lumped rainfall-runoff models for hillslopes adjacent to a river channel and a kinematic flow routing model for the river channel. The system is updated by Particle filtering of the downstream part model as well as by the extended Kalman filtering of the upstream part model. The Particle filtering is a simple and powerful updating algorithm for non-linear and non-gaussian system, so that it can be easily applied to the downstream part model without complicated linearization. The system applied to the Yoshii River Basin located in Okayama Prefecture, and flood forecasting accuracy of the developed system was examined. The comparison between the forecasting accuracy of the system with both Particle filtering and extended Kalman filtering and that with only extended Kalman filtering shows that Particle filtering of the downstream part model well improves forecasting accuracy particularly for the basin having relatively large area ratio of the downstream part.
With understanding the livestock farming on cattle breeding practiced increasing of self-production of fodders by the farmland's operation as “Livestock Farming with crop production”, we investigated the utilizations of actual fodder resources and farmland for two selected different types of livestock farming systems: “Multiple Type” which practices cattle raising with fodder cultivation, and “Grazing Type” which practices grazing and fodder cultivation with similar feed self-sufficiency rates. We also prepared and compared material and nitrogen flow of both livestock farming systems. The amount of nitrogen flow is clearly different between the two types though feed self-sufficiency rates are at similar level. Moreover, we defined “Internal Nitrogen Rate (INR)” which indicates the rate of internal nitrogen use to total nitrogen use in cattle raising, “Internal Nitrogen Circulation Rate (NCR)” which indicates the ratio of nitrogen amount in internal circulation to the nitrogen amount introduced from outside, and Nitrogen Outflow Potential (Op), which is the balance of nitrogen amount between input to farmlands and uptake by plants, and analyzed the balance of the amounts of nitrogen flows in both livestock farming type. It is suggested that “Grazing type”, which had the values of relatively high NCR and absolutely low Op, was the livestock farming type with high rates of nitrogen procurement from the interregional farming and low risk of nitrogen outflow.
The insecticides fipronil and imidacloprid are effectively used against sucking insect pests of rice. Since these agents are absorbed by rice seedlings and stored in their tissues, they are usually applied to nursery boxes before planting. The effects of imidacroprid and fipronil on the life history of Sympetrum frequens larvae and adults were monitored using an experimental micro-paddy lysimeter(350mm× 500mm× 300mm (H)) for the duration of the cultivation period. Three lysimeters were treated with imidacroprid, three with fiproni, and the remaining three were left untreated and were used as controls. Three hundred eggs were laid on the soil surface of each of the nine lysimeters and the larval populations, larval development, and emergence patterns of Sympetrum frequens were observed in each lysimeter. The absence of Sympetrum frequens larvae from fipronil-treated-lysimeters was most remarkable and exuviae were not observed. Imidacroprid-treated-lysimeters had approximately 60% of the larvae observed in control lysimeters. In addition, larvae in the imidacloprid lysimeter had lower mean specific growth rates and the length of adult wings was decreased relative to those observed in the control lysimeter. Emergence in imidacloprid lysimeters was also significantly lower than it was in the control. The application of fipronil and imidacroprid to seedling in the nursery box, and the subsequent transplanting of these into an experimental lysimeter, was associated with a decrease in the abundance of Sympetrum frequens larvae and adults.
Thrust force acts on pipe bend due to internal pressure. In previous study, the lightweight thrust restraint with geogrid and anchor plate has proposed and the effect has been proved by conducting lateral loading model tests. In the present study, a series of model tests for changing depth of cover and length of restraint were carried out, and image analysis for the ground surface in the model tests were carried out to discuss the failure mechanism of proposed method. Furthermore, the failure mechanisms in front of the anchor plate were assumed and the additional resistances due to the proposed method were calculated based on the force equilibrium. In addition, in order to examine the accuracy for the proposed formula, calculated values were compared with experimental values. As the results, additional resistance from calculation was corresponding to experimental value.
Water quality was surveyed at 36 locations in agricultural watersheds of Shari and Abashiri region in Hokkaido to examine how the nitrate nitrogen concentration in the river water there varies with land use. The land-use categories of upland field which includes grasslands and forested land were chosen, because they are the main land-use categories of the subject areas. As land-use indexes, in addition to the generally used percentage of upland field, we used the Connections Number (CN), which expresses land-use agglomeration, and Spatial Continuity (SC), which expresses the spatial continuity of land use of the same kind. Percentage of upland field was found to strongly corelate with nitrate nitrogen concentration of river water, confirming that nitrogen from upland fields influences the nitrogen contamination of river water. A positive correlation was found between the CN and SC of upland field and the nitrate nitrogen concentration of river water, and a negative correlation was found between the CN and SC of forestted land and the nitrate nitrogen concentration of river water. This clarified that, in addition to the percentage of upland field, the distribution of land use, such as agglomeration and spatial continuity of the land use of the same kind, relate to the nitrate nitrogen concentration of river water.
The earthfill structure such as embankments, which are constructed for the preservation of the agricultural land, has shown large settlement in the middle of the construction and after construction in the lowland area on the coast of the Ariake Sea, and then the long term settlement of those buildings is measured. The hyperbolic method is one of the most famous methods that predicting the settlement by using measurement records and is used extensively both domestically and internationally. In this paper the neural network model for predicting settlement by using measurement records in early stage is examined. Using the learning pattern that focused on the convergence of settlement rate, the prediction values are good agreement with the measured values. As a result, having the model learn the data that has a suitable regularity, the proposed method can provide the early prediction of settlement with high accuracy.
This paper discusses the limit state design method for the shallow foundations under open channels. The partial factors of modified Terzaghi's formula are proposed for the vertical bearing capacity of foundation within the framework of ‘partial factors design procedure.’ Firstly, the coefficient of variations of the soil parameters are evaluated based on the published data record, and the reliability analysis is carried out for the existing sixteen open channels designed by conventional method. Then, the ultimate bearing capacity is compared with the corresponding allowable bearing capacity of the conventional design method, and the appropriate target reliability index is determined. The partial factors are numerically evaluated to satisfy the target reliability indices, and the expected values of partial factors are calculated. Finally, the calibration analysis is performed based on the expected values, and the optimum set of partial factors is proposed.
Recently it is desirable to realize the conservation of biodiversity and to create the city with symbiosis with nature even in local city. In this study, we chose Nagano City which was the site of the Winter Olympic Games as the subject of study, investigated the change of land cover by using Landsat TM data of the year 1985 and 1999 which were before and after the Winter Olympic Games, and grasped the change of landscape structure quantitatively by using landscape indices. As a result, we obtained the following conclusions. The expansion of urban area proceeded rapidly before and after the Winter Olympic Games. The area of artificial land cover in the city planning area has increased by 57%. In the meantime the areas of upland field and paddy field have decreased by 45% and 50% respectively. Therefore, agricultural land changed into urban area remarkably. It was found that the shape of paches of paddy field and upland field especially became small and the inequality of the paches decreased before and after the Winter Olympic Games. It became clear that the fragmentation has occurred in agricultural land such as paddy field, upland field and orchard.
In the irrigated upland field area, measurement of water volume for different purposes of lot-management water is not enough. In this paper, the actual status of the usage of lot-management water at upland fields is surveyed in Inami Town, Wakayama prefecture. It is cleared that the water use for spray irrigation for liquid fertilizer application and disinfection are included in the water use for water replacement. It is cleared that the water use for solarization, fix planting and removal of tidal damage occur in a different epoch of the occurrence of the water use for water replacement, and/or the amount of them exceeds the amount of water replacement. And it is showed that lot-management water for solarization and fix planting are placed in design irrigation requirement to consider the combination of cultivated plants and/or to put off the date for irrigation in this study field. The amount of the water necessary for removal of tidal damage can be reduced by improvement of equipment and considering the cultivated plants.
Disaster assessment, which specifies the contents and the scale of a disaster restoration works, is one of the most important work in disaster restoration project. This paper examines the problems related to the assessment of the agricultural infrastructure and facility encountered by the local governments in the Mid-Niigata Prefecture Earthquake in 2004. Comparing to the enormous destruction the earthquake brought about, the period of assessment activities was fairy limited and the work load was concentrated at this time. In order to ease the work load concentration, simplified assessment system, such as “Model System” and “Typical Section System” were introduced. In spite of the fact that these efforts help expedite the works, some issues remained. Moreover, although the farmers had requested the improvement restoration work for their damaged farmland, an expedience was emerged that the customary systems could not allow enough this improvement. This paper clarifies the advantages of the improved systems introduced for the disaster assessment, and to propose measures to address the newly imaged issues.
The objective of this study was to investigate the applicability of phytoextraction with a Cd-hyperaccumulator plant (Arabidopsis halleri ssp. gemmifera) to remediate Cd-contaminated Andisols. Cd absorption potentials of this plant for Andisols were examined in pot experiments. Sequentially, phytoextraction durations for remediation of Cd-contaminated Andisols were calculated from the experimental data. The results were as follows: (1) Cd concentrations in the plant shoots ranged from 170-750 mg⋅kg-1. (2) Cd absorption of the plant for Andisols with ALC (Autoclaved Lightweight aerated Concrete) was less than for Andisols without ALC. However, the plants absorbed the same amount of soil Cd extracted by 0.01 M HCl with or without ALC. (3) Calculations suggest that the applicability of phytoextraction with this plant is high for slightly contaminated Andisols. Therefore, phytoextraction with Arabidopsis halleri ssp. gemmifera may be a viable option for the remediation of Cd-contaminated Andisols.