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71.
A modern computer-based simulation tool (WaterMan) in the form of a game for on-farm water management was developed for application in training events for farmers, students, and irrigators. The WaterMan game utilizes an interactive framework, thereby allowing the user to develop scenarios and test alternatives in a convenient, risk-free environment. It includes a comprehensive soil water and salt balance calculation algorithm. It also employs heuristic capabilities for modeling all of the important aspects of on-farm water management, and to provide quantitative performance evaluations and practical water management advice to the trainees. Random events (both favorable and unfavorable) and different strategic decisions are included in the game for more realism and to provide an appropriate level of challenge according to player performance. Thus, the ability to anticipate the player skill level, and to reply with random events appropriate to the anticipated level, is provided by the heuristic capabilities used in the software. These heuristic features were developed based on a combination of two artificial intelligence approaches: (1) a pattern recognition approach and (2) reinforcement learning based on a Markov decision processes approach, specifically the Q-learning method. These two approaches were combined in a new way to account for the difference in the effect of actions taken by the player and action taken by the system in the game world. The reward function for the Q-learning method was modified to reflect the suggested classification of the WaterMan game as what is referred to as a partially competitive and partially cooperative game. 相似文献
72.
Kiran Prasad Bhatta Akira Ishida Kenji Taniguchi Raksha Sharma 《Irrigation and Drainage Systems》2006,20(2-3):177-191
Management reforms are considered one of the best alternatives in increasing efficiency of the irrigation systems. Transfer of day-to-day operation and maintenance to farmers is not a new concept. However due to lags, even now it is a hot issue in developing countries and Nepal is not an exception. In this context of growing argument about the transfer of management of public irrigation systems to the Water Users' Group, this paper examines the comparative performance of farmer-managed and agency-managed irrigation systems. Khageri Irrigation System in the Chitwan district of Nepal was taken as the study site where complete management transfer has been done in 1996. The situations before and after complete transfer were compared. Intensive case studies of the selected farmers showed that equity in distribution of water and leakage had significantly improved after management transfer. Logit analysis revealed that age and education level of the household head, distance from main canal, leakage of the canal and equity in distribution are significantly related to the satisfaction level of the beneficiary farmers from FMIS compared to AMIS. However, landholding size of the respondent farmer has no significant effect. Similarly results from t-test revealed that rice productivity and overall profits from agriculture has also increased significantly due to irrigation management transfer. 相似文献
73.
Purpose
Carbon nanomaterials (CNMs) have attracted a great deal of research interest for their potential environmental applications because of their unique properties. Adsorption of organic chemicals on CNMs was reported to be important in controlling their environmental risks. However, the kinetics of the adsorption is hardly investigated in literature. The objective of this work was, therefore, to quantitatively describe the sorption kinetics of 17 α-ethinyl estradiol (EE2) and bisphenol A (BPA) on CNMs as compared to activated carbon (AC). 相似文献74.
Ruijuan Li Jinfeng Zhao Chuanfan Sun Wenjing Lu Chengjin Guo Kai Xiao 《Frontiers of Agriculture in China》2010,4(2):195-209
As a kind of enzyme widely existing in eukaryotic species, especially in grains and oil seeds, phytases play an important
role in the degradation of some phosphates containing organic molecules. So far, phytases derived from various species have
been successfully used as animal feed additives. It has also been experimentally verified that phytases have a potential use
in generating crop germplasm with high phosphorus use efficiency, based on their biochemical role in releasing Pi from the
phytate and its derivatives. In this paper, the biochemical properties, molecular characterizations, functions and the potential
application perspective of phytases are reviewed and commented on, aiming at the further exploration of the biochemical and
molecular characterizations, and promotion of the application of phytases, a kind of important enzyme possessing potential
use in animal feeding and creation of high P use crop cultivars, in the future. 相似文献
75.
Yoshikazu Kiriiwa Sunao Osumi Masanobu Endo Akira Nukaya Akio Morita Hiromi Yokota 《Soil Science and Plant Nutrition》2013,59(7):1119-1124
Abstract In alkaline soils, plant growth is impaired mainly by high pH and high concentration of bicarbonates. The bicarbonate concentration increases the pH value, and causes deficiency of iron. A bicarbonate-resistant cell line (BR line) of tobacco (Nicotiana tabacum L. cv. Burley21) was selected by adding excess bicarbonate ions (20 mmol L?1) to the culture medium. The pH of the medium was buffered 8.0 to 8.3. Under these conditions, about 80% of iron in the medium became insoluble. However, under such conditions, the BR line grew well. In this report, we examined some characteristics of the growth and iron uptake in the BR line under iron-deficient (i.e. high pH or no-iron) condition. At pH 5.8, the Fe3+ reduction activity was not significantly different between the non-selected line and the BR line. At pH 8.0, however, the Fe3+ reduction activity of the BR line was higher than that of the non-selected line. In no-iron condition, the growth of the non-selected line was markedly reduced after 2 weeks, while the BR line was not affected. The content of malic acid in both lines increased with the medium pH, and the content in the BR line was higher than that in the non-selected line. The BR line was able to adapt to the conditions, which restricted iron uptake, such as high bicarbonate concentration, high pH, and low iron conditions. The high ability of Fe3+ reduction was maintained at even high pH conditions. Further, the BR line may be able to improve the utilization of iron in the cells. 相似文献
76.
77.
Xing-Pu Li Su-Que Lan Ye-Lun Zhang Yu-Ping Liu 《Genetic Resources and Crop Evolution》2010,57(7):1007-1012
Pericarp color in wheat is an important trait related to nutrients and health benefits. Identification of molecular markers
closely linked to the grain color genes will help utilize pericarp trait in wheat breeding. Genetic studies involving F1, F2, and F3 populations from the cross Jizi 439 (purple grain)/Gao8901 (white grain) showed that the purple grain color was controlled
by two genes. By using the bulked segregant analysis (BSA) approach, two DNA pools were established from the dark purple-grain
and white-grain plants respectively. Among the 230 pairs of microsatellite primers used in this study, two markers showed
polymorphism in DNA pools, parents, F1 and F2 populations. Linkage analysis indicated that the two markers Xgwm47 and Xgwm155 were linked with two purple pigment genes. One of the purple pigment genes is located on chromosome 2AS and is 34.7cM away
from the marker Xgwm47, whereas another gene is mapped on 3AL with 14.7cM away from marker Xgwm155. 相似文献
78.
79.
80.
Living in poverty is associated with high levels of protracted stress associated with health problems. Economic and food insecurity
are particularly poignant aspects of poverty and condition the work of securing basic daily needs of families. Recent studies
suggest that levels of stress increase as family food needs rise. This paper presents new findings which clarify the relationship
of food provisioning to stress levels, by examining actual food provisioning strategies and food insecurity among the Northern
Cheyenne Indians of southeastern Montana. Results clearly show that stress varies by types of food acquisition strategies.
Contrary to our expectations, more complex strategies, including relatively unpredictable and cumbersome food provisioning
activities, are not linked to higher stress levels in our analysis. Controlling for food security levels, households using
a combination of local programs and informal subsistence sources are the least stressed, despite the demands of managing a
large number of food sources. Households primarily using Food Stamps are the most likely to experience high levels of stress.
Interviews with Food Stamp recipients show that potential sources of stress include inadequate allocations of Food Stamps,
difficulty achieving and maintaining eligibility, challenges to complying with paperwork and appointment requirements, as
well as personal obstacles and community barriers to making food stamps last. Analyses indicate that contradictions between
local cultural norms for food provisioning and the realities of food insecurity in this context promote strategies emphasizing
greater independence from federal food programs. 相似文献