504 research outputs found
Nitrate Contamination of Groundwater and Soil Management
No full textThe Japanese Government set the environmental quality standard for nitrate (NO3) in groundwater at 10 mg N L1 in 1998, based on a level considered acceptable for avoiding infant methemoglobinemia. In 1998, 6.3% of groundwater in Japan contained NO3 exceeding 10 mg L¡¦, with agriculture regarded to be a primary source of the NO3 (Environmental Agency, Japan, 1999). This paper aims to define the mechanisms of NO3 contamination of groundwater associated with soil management in arable land.
The author gives an overview of the relation between nitrogen (N) fertilization and groundwater contamination. First of all, the utilization efficiency of N fertilizers for outdoor cultivation of vegetables is usually 50% or less (Nishio, 2001; Vance, 2001). Although N fertilizer is essential for crop production, excessive N could leach out of arable soils and eventually cause NO3 contamination of groundwater. However, conversely, excessive N is necessary as insurance in some cases, such as when there is heavy rainfall immediately after fertilization. It should be also noted that some vegetables physiologically require a high content of N in soil even at harvest.
Nitrate leaching from different fertilizers was monitored for 7 years and the data were evaluated using an N and water balance equation (Maeda et al., 2003). Excessive N from chemical fertilizers caused substantial NO3 leaching, while compost application was promising to achieve high yields and low N leaching during a few years but led to the same level of NO3 leaching as that in the plots subjected to chemical fertilizer application over longer periods of time. Thus, it is of importance to predict the N mineralization rates both for manure and for soil under natural conditions. Experimental results of this kind can provide full information on N dynamics in fields for policy decisions or regulations to reduce NO3 leaching while maintaining crop yields. Likewise, we must consider other influencing factors such as soil types, climatic conditions, and cropping systems for this purpose
Formation process and metamorphism on R chondrite parent body based on distribution of rare earth elements, Th and U.
No full text第8回極域科学シンポジウム/個別セッション：[OA] 南極隕石
12月6日（水）国語研究所 2階講堂
The Eighth Symposium on Polar Science/Ordinary sessions: [OA]
The Eighth Symposium on Polar Science/Ordinary sessions: [OA Antarctic meteorites
Wed. 6 Dec./2F Auditorium, National Institute for Japanese Language and Linguisticsconference objec
Formation process and metamorphism on R chondrite parent body based on distribution of rare earth elements, Th and U.
No full textChemical and isotopic characterization of Antarctic meteorites: The chemical and isotopic effects of thermal processing and terrestrial weathering on the (re-)distributions of trace elements in chondrites
No full textMy PhD research aims to encompass a detailed chemical and isotopic characterization of “well-preserved” Antarctic meteorites to improve our understanding of the (re-)distribution of various trace elements in specific meteorite types and the effects of the (re-)distribution on radiogenic isotope systematics. As Antarctic meteorites can be affected by alteration, prior to the investigation of the elemental distribution in meteorites and the isotopic effects of the (re-)distribution, the first task of this work has been dedicated to assessing the effects of Antarctic alteration on the chemical and isotopic compositions of ordinary chondrites, the most abundant class of meteorites, and more specifically on H group of ordinary chondrites. The main focus is placed on the systematic study of rare earth elements including their isotope systematics such as Sm-Nd and Lu-Hf.This PhD thesis first demonstrates that the effects of Antarctic alteration on the Sm-Nd and Lu-Hf systems in bulk H chondrites are generally limited and thus the Sm-Nd and Lu-Hf systems preserve their original compositions during Antarctic alteration. Secondly, the underlying mechanism of Antarctic alteration observed in the first part of the PhD study is investigated using in-situ measurement techniques including state-of-the-art laser ablation-inductively coupled plasma-time of flight-mass spectrometry (LA-ICP-TOF-MS). Simultaneously, the potential of LA-ICP-TOF-MS as a novel technique to study the elemental distribution is examined and evaluated. Finally, the distribution of lithophile elements among the constituent minerals in H chondrites is documented at the microscale and their re-distribution during thermal metamorphism in the parent body(ies), i.e. the thermal effects of the lithophile element distribution are quantified and discussed, with a direct link to the heterogeneity recorded in the Sm-Nd and Lu-Hf isotope systematics of bulk chondrites. Overall, this thesis confirms the generally pristine nature of Antarctic meteorites and describes the thermal processes that took place in the parent bodies of ordinary chondrites.Cette thèse de doctorat vise à apporter une caractérisation chimique et isotopique détaillée des météorites antarctiques considérées comme « bien conservées" afin d'améliorer notre compréhension de la (re-)distribution de divers éléments en traces dans des types de météorites spécifiques ainsi que pour les systèmes isotopiques radiogéniques. Comme les météorites antarctiques peuvent être affectées par l'altération, avant l'étude de la distribution élémentaire dans les météorites et les effets isotopiques de la (re-)distribution, la première tâche de ce travail a été consacrée à l'évaluation des effets de l'altération antarctique sur les compositions chimiques et isotopiques des chondrites ordinaires, la classe la plus abondante de météorites, et plus précisément du groupe H des chondrites ordinaires. L'accent est mis sur l'étude systématique des éléments des terres rares, y compris leur systématique isotopique Sm-Nd et Lu-Hf.Ce travail démontre d'abord que les effets de l'altération antarctique pour les systèmes Sm-Nd et Lu-Hf dans les chondrites de type H sont généralement limités et donc que ces systèmes conservent leurs compositions d'origine lors de l'altération antarctique. Deuxièmement, le mécanisme sous-jacent de l'altération antarctique a été étudié à l'aide de techniques de mesure in situ, notamment l'ablation laser et la spectrométrie de masse plasma-temps de vol à couplage inductif (LA-ICP-TOF -MS). Simultanément, le potentiel du LA-ICP-TOF-MS en tant que nouvelle technique pour étudier la distribution élémentaire a été examiné et évalué. Enfin, la distribution des éléments lithophiles parmi les minéraux constitutifs des chondrites H est documentée à l'échelle microscopique et leur redistribution lors du métamorphisme thermique dans le ou les corps parents. Ainsi, les effets thermiques de la distribution des éléments lithophiles sont quantifiés et discutés, avec un lien direct avec l'hétérogénéité enregistrée dans la systématique isotopique Sm-Nd et Lu-Hf des chondrites. Dans l'ensemble, cette thèse confirme la nature généralement intacte des météorites antarctiques et identifie les processus thermiques qui ont eu lieu sur les corps parents des chondrites ordinaires.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
Development of environment-friendly aquaculture technologies and practices
No full textThe significant role of aquaculture in providing food security has been recognized, not only through its contribution to food supply, but also through the promotion of economic and social well-being. Aquaculture is also considered as a relatively recent and underdeveloped sector as compared to agriculture and animal husbandry, and there is a huge, unfulfilled potential in many countries, particularly in the region. The recently concluded ASEAN-SEAFDEC Conference “Fish for the People” highlighted the importance of sustainable fisheries for regional food security, and the need for comprehensive and cooperative efforts, resolutions and plan of actions among all stakeholders. With the projected shortfall in the supply of fish and fishery products to meet the demands of an ever-increasing population, aquaculture is looked upon as a sustainable source of renewable food resources.
One of the main programs of the SEAFDEC Aquaculture Department (AQD) is geared towards the development of sustainable aquaculture that is technically feasible, economically viable, environment-friendly, and socially equitable. An important subprogram is the development of environment-friendly aquaculture technologies and practices. The objectives of the subprogram are: 1) to develop and promote efficient aquaculture systems and designs for maximum sustainable productivity; 2) to devise and determine appropriate design, equipment, and operation and management practices that optimize utilization of resources and inputs, minimize adverse impacts on the environment, and sustain biological/ecological diversity; 3) to demonstrate, verify, adopt, refine, and promote proven aquaculture technologies and practices; and 4) to advance the social, economic, cultural, and policy importance of the aquaculture sector at the local, national, and regional level. At present, the main research areas are in nutrient dynamics of aquaculture systems, feed and waste management, development of culture systems, including bioremediation strategies, conservation and sustainable utilization of resources for aquaculture, and socio-economic and policy issues in aquaculture. In addition, verification and refinement of developed aquaculture technologies, in support of re search and training activities, are conducted to explore the potential of aquaculture technologies for commercial adoption and demonstrate appropriate technologies and responsible aquaculture practices. The paper presents an overview of current research activities by the author, and with involvement of other researchers at SEAFDEC AQD, including future plans under this and related programs
« Parsadan Gorgijanidze’s Exile in Shushtar: A Biographical Episode of a Georgian Official in the Service of the Safavids ». Journal of Persianate Studies 1, 2, 2008, p. 218-229.
No full textAt the beginning of the article, Maeda states his opinion that many Safavid ġolāms were far from severing all ties with their homeland: here the Author agrees with the views of other modern Safavid scholars but he (rightly, in the opinion of the present reviewer) contradicts what one often reads in the scholarly literature concerning military slavery in the Muslim world in general. Maeda is also correct in stating that “by introducing the institution of the royal ġolāms, the Safavids imported..
Relationship between domoic acid levels in the blue mussel (Mytilus-edulis) and toxicity in mice
No full textPT: J; CR: 1988, CAN CHEM NEWS, V10, P15 BATES SS, 1988, 57 NAT RES COUNC CAN BIRD CJ, 1988, 56 NAT RES COUNC CAN BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248 COYLE JT, 1984, EXCITOTOXINS, V39, P112 DEBONNEL G, 1989, CAN J PHYSIOL PHARM, V67, P29 FRANSON MA, 1980, STANDARD METHODS EXA IMPELLIZZERI G, 1975, PHYTOCHEMISTRY, V14, P1549 LAWRENCE JF, 1989, J CHROMATOGR, V462, P349 LITCHFIELD JT, 1949, J PHARMACOL EXP THER, V96, P99 MAEDA M, 1987, PESTIC BIOCHEM PHYS, V28, P85 QUILLIAM MA, 1988, 55 NAT RES COUNC CAN RAO DVS, 1988, CAN J FISH AQUAT SCI, V45, P2076 TAKEMOTO T, 1958, CHEM PHARM BULL, V6, P578 TAKEMOTO T, 1978, KAINIC ACID TOOL NEU, P1 WILLIAMS S, 1984, OFFICIAL METHODS ANA, P344 WRIGHT JLC, 1989, CAN J CHEM, V67, P481; NR: 17; TC: 21; J9: TOXICON; PG: 8; GA: DF893Source type: Electronic(1
Axisymmetric polydimethysiloxane microchannels for in vitro hemodynamic studies
No full textThe current microdevices used for biomedical research are often manufactured using microelectromechanical systems (MEMS) technology. Although it is possible to fabricate precise and reproducible rectangular microchannels using soft lithography techniques, this kind of geometry may not reflect the actual physiology of the microcirculation. Here, we present a simple method to fabricate circular polydimethysiloxane (PDMS) microchannels aiming to mimic an in vivo microvascular environment and suitable for state-of-the-art microscale flow visualization techniques, such as confocal µPIV/PTV. By using a confocal µPTV system individual red blood cells (RBCs) were successfully tracked trough a 75 µm circular PDMS microchannel. The results show that RBC lateral dispersion increases with the volume fraction of RBCs in the solution, i.e. with the hematocrit
Study on seismic performance evaluation of cylindrical latticed shells supported by substructures
No full textEstimation method for dynamic ductility index of steel structures by using of equivalent linearization method
No full text- …
