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1.
Abstract

Increasing water scarcity, degradation of land and water resources, continuing low agricultural productivity, and increasing populations are posing the largest ever challenges for development of agricultural economies in many developing countries including Pakistan. Using panel data from irrigated settings in Chaj sub-basin of the Indus basin in Pakistani Punjab, we attempt to: (a) analyze the causes of low productivity; (b) disentangle factors (both land, water and other factors) contributing to productivity variations; and (c) identify limits and opportunities for narrowing productivity gaps and increasing overall wheat production, with a view to enhance food security for the poor. The results of the study indicate that locational inequities in distribution of canal water, use of groundwater of varying quality, differences in use of seed varieties, and other inputs lead to significant variations in wheat productivity. Key implications are that large gains in wheat productivity are possible by (a) improving the production environment at the tail-end through integrated water management practices; (b) adjusting the mix of canal and groundwater use; and (c) using technological interventions to improve the adoption of modern wheat varieties and dissemination of knowledge on planting dates and timings and application rates of inputs, especially water and fertilizer. Not only such interventions are economically, financially, and environmentally desirable, they are also pro-poor. What is needed is a strong political will and commitment.  相似文献   
2.
Abstract

There is increasing recognition of the problems facing China in meeting the growing water demand in the Yellow River basin, the “cradle of Chinese Civilization” and a critically important agricultural and industrial region. Meaningful debate on the range and relative costs of options available to policy-makers in addressing the problem depend fundamentally on an accurate understanding of basin water resources. Unfortunately, the ability of outsiders to participate in the de bate and for Chinese, with their long history of water management, to contribute to similar discussions elsewhere in the world is hindered to some extent by a lack of understanding of differences in water accounting systems and concepts. This paper attempts to address this problem by describing the water accounting system used in the Yellow River basin and elsewhere in China. The paper shows that the primary difference between water accounting methodologies in the Yellow River and those typically applied elsewhere is related to supply accounting in general and groundwater accounting in particular. Although not currently included in its water accounting system, Chinese concepts of environmental water use, when included, will also differ substantially from those familiar to outside researchers. In terms of actual Yellow River balances, the paper highlights the apparent declining trend in basin rainfall and runoff and the dramatic growth in industrial and domestic water use. Together declining supply and rising demand will increasingly cause policy-makers to face hard choices in assessing their water planning options. These choices will only become more difficult as managers in the Yellow River, as elsewhere in the world, try to incorporate ecological needs in the water accounting equation.  相似文献   
3.
Cytokine receptors have been shown in cell culture systems to use phosphotyrosine residues as docking sites for certain signal transduction intermediates. Studies using various cellular backgrounds have yielded conflicting information about the importance of such residues. The present studies were undertaken to determine whether or not tyrosine residues within the erythropoietin receptor (EPOR) are essential for biologic activity during hematopoiesis in vivo. A variant of the EPOR was constructed that contains both a substitution (R129C) causing constitutive receptor activation as well as replacement of all eight cytoplasmic tyrosines by phenylalanines (cEPORYF). A comparison between animals exposed to recombinant retroviruses expressing cEPOR and cEPORYF showed that efficient red blood cell (RBC) development in vivo is dependent on the pressence of tyrosine residues in the cytoplasmic domain of the EPOR. In addition, an inefficient EPOR tyrosine independent pathway supporting RBC development was detected. Tyrosine add-back mutants showed that multiple individual tyrosines have the capacity to restore full erythropoietic potential to the EPOR as determined in whole animals. The analysis of primary erythroid progenitors transduced with the various cEPOR tyrosine mutants and tyrosine add-backs showed that only tyrosine 343 (Y1) and tyrosine 479 (Y8) were capable of supporting immature burst-forming unit-erythroid progenitor development. Thus, this receptor is characterized by striking functional redundancy of tyrosines in a biologically relevant context. However, selective tyrosine residues may be uniquely important for early signals supporting erythroid development.  相似文献   
4.
In many river basins, patterns of water withdrawals, deliveries, depletion, return flows, and reuse are prevalent. These cascading systems, often misunderstood, provide opportunities, but also threats to livelihoods and environment. Different ways of thinking about these cascading systems are required.  相似文献   
5.
Much of psychology focuses on universal principles of thought and action. Although an extremely productive pursuit, this approach, by describing only the "average person," risks describing no one in particular. This article discusses an alternate approach that complements interests in universal principles with analyses of the unique psychological meaning that individuals find in their experiences and interactions. Rooted in research on social cognition, this approach examines how people's lay theories about the stability or malleability of human attributes alter the meaning they give to basic psychological processes such as self-regulation and social perception. Following a review of research on this lay theories perspective in the field of social psychology, the implications of analyzing psychological meaning for other fields such as developmental, cultural, and personality psychology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
Water Accounting to Assess Use and Productivity of Water   总被引:1,自引:0,他引:1  
A methodology is demonstrated to account for the use and productivity of water resources. This water accounting methodology presents useful information to water resource stakeholders and decision makers to better understand the present use of water and to formulate actions for improvements in integrated water resources management systems. Based on a water balance approach, it classifies outflows from a water balance domain into various categories to provide information on the quantity of water depleted by various uses, and the amount available for further use. The methodology is applicable to different levels of analysis ranging from a micro level such as a household, to a macro level such as a complete water basin. Indicators are defined to give information on the productivity of the water resource. Examples from Egypt's Nile River and a cascade of tanks in Sri Lanka are presented to demonstrate the methodology.  相似文献   
7.
Five studies examined hypothesis generation and discounting in causal attribution from the perspective of regulatory focus theory (E. T. Higgins, 1997, 1998). According to this theory, a promotion focus is associated with generating more and simultaneously endorsing multiple hypotheses, whereas a prevention focus is associated with generating only a few hypotheses and selecting 1 hypothesis from a given set. Five studies confirmed these predictions for both situationally induced and chronic individual differences in regulatory focus. In Studies 1, 2, and 3, individuals in a promotion focus generated more hypotheses than individuals in a prevention focus. In Studies 4 and 5, individuals in a promotion focus discounted explanations in light of alternatives less than individuals in a prevention focus. Study 5 also found that in a promotion focus, person explanations were generalized across situations less than in a prevention focus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
People experience regulatory fit when they pursue a goal in a manner that sustains their regulatory orientation (E. T. Higgins, 2000). Five studies tested whether the value experienced from regulatory fit can transfer to a subsequent evaluation of an object. In Studies 1 and 2, participants gave the same coffee mug a higher price if they had chosen it with a strategy that fit their orientation (eager strategy/promotion; vigilant strategy/prevention) than a strategy that did not fit. Studies 3-5 investigated possible mechanisms underlying this effect. Value transfer was independent of positive mood, perceived effectiveness (instrumentality), and perceived efficiency (ease), and occurred for an object that was independent of the fit process itself. The findings supported a value confusion account of transfer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
10.
The Hindu Kush Himalayas are called the water towers of Asia as they are the source of 10 major rivers and have the largest snow and ice deposits outside the two poles. Water emanating from the HKH provides food, energy and ecosystem services to up to 1.3 billion people. Climate change and socio-economic and demographic changes have put unprecedented pressure on these water resources, leading to uncertain supplies, increased demands and higher risks of extreme events like floods and droughts. The eight articles in this special issue highlight various dimensions of the Himalayan water resources by focusing on both physical and social science aspects of water management.  相似文献   
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