611 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
Greek wh-Questions and the Phonology of Intonation
No full textThe intonation of Greek wh-questions consists of a rise-fall followed by a low plateau and a final rise. Using acoustic data, we show (i) that the exact contour shape depends on the length of the question, and (ii) that the position of the first peak and the low plateau depends on the position of the stressed syllables, and shows predictable adjustments in alignment, depending on the proximity of adjacent tonal targets. Models that specify the F0 of all syllables, or models that specify F0 by superposing contour shapes for shorter and longer domains, cannot account for such fine-grained lawful variation except by using ad hoc tonal specifications, which, in turn, do not allow for phonological generalisations about contours applying to utterances of greatly different lengths. In contrast, our findings follow easily from an autosegmental-metrical approach to intonational phonology, according to which melodies may contain long F0 stretches derived by interpolation between specified targets associated with metrically strong syllables and prosodic boundaries
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
<abstruct>A method for the sterile culture of housefly larvae, Musca domestica L ; The influence of spray programs on the fauna of apple orchards in Nova Scotia, V. The predacious thrips ; Rearing the Cadelle Tenebroides mauritanicus (L.)(Coleoptera: Ostomidae) as a Test Insect for Insecticidal Research ; The relative control values of different percentage mortalities
No full text« 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..
A study on harmonic power of lead type operating circuit for high pressure mercury discharge lamp.
No full text
Characterization of Escherichia coli Persisters from Biofilm Culture: Multiple Dormancy Levels and Multigenerational Memory in Formation
No full textPersister cells (PCs), a subpopulation occurring within normal cells, exhibit a transient tolerance to antibiotics because of their dormant state. PCs are categorized into two types: type I PCs, which emerge during the stationary phase, and type II PCs, which emerge during the logarithmic phase. Using the conventional colony-forming method, we previously demonstrated that type I PCs of Escherichia coli form more frequently in air–solid biofilm culture than in liquid culture. In the current study, we modified a cell filamentation method as a more efficient and rapid alternative for quantifying PCs. This modified method yielded results consistent with those of the conventional method with 103–104 times higher sensitivity and less detection time, within several hours, and further revealed the existence of multiple levels of type I PCs, including a substantial number of deeply dormant cells. This study also discovered a potential epigenetic memory mechanism, spanning several generations (four or six cell divisions), which influences type II PC formation based on prior biofilm experience in E. coli
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