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51.
Improvements in irrigation efficiency are well documented when changing from flood to sprinkler irrigation methods; however, other impacts to the watershed associated with this change are not well known. The resulting impacts to a river basin hydrology when irrigation and conveyance methods are changed are the focus of this study. In an attempt to improve water application and conveyance efficiencies in the Salt River Basin of western Wyoming, irrigation practices were changed from flood irrigation to sprinkler irrigation beginning in the late 1960s, with completion by the mid-1970s. Based upon a water balance, flow in the Salt River increased an average of 65.62 MCM/year. Return flow timing was also impacted by the conversion to sprinkler irrigation. Flows increased 34% in May and 50% in June, while decreasing 15 and 14% in August and September. These changes may have coincided with decreases in groundwater storage. However, analysis of changes in groundwater levels with time was inconclusive. Surface water total dissolved solids (TDS) appears unaffected by the conversion in irrigation practices, while limited groundwater quality data indicate that TDS values are lower in sprinkler irrigated areas. 相似文献
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Scicli Andrea P.; Petrovich Gorica D.; Swanson Larry W.; Thompson Richard F. 《Canadian Metallurgical Quarterly》2004,118(1):5
Fos, the protein product of the immediate early gene c-fos, was used to map functional circuitry underlying contextual conditioned fear. Male rats were given footshocks in a distinctive context and later tested using freezing as the behavioral measure and compared with no-shock and no-retention-test control groups. An increased number of Fos-immunoreactive neurons was found in the lateral part of the central nucleus and in the anterior basolateral and lateral amygdalar nuclei in the brains of the conditioned-fear group compared with controls. Further, a greater number of Fos-immunoreactive neurons was observed in the right central and anterior basolateral nuclei compared with the number of labeled neurons in these structures on the left. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Chaney John M.; Mullins Larry L.; Wagner Janelle L.; Hommel Kevin A.; Page Melanie C.; Doppler Matthew J. 《Canadian Metallurgical Quarterly》2004,49(2):126
Objective: Examine longitudinal relationships between causal attributions and depression symptoms in adults with rheumatoid arthritis (RA). Study Design: Cross-lagged panel correlations tested the temporal precedence of attributions relative to depression symptoms over 1 year. Participants: Forty-two participants completed self-report instruments on 2 occasions. Main Outcome Measures: The Inventory to Diagnose Depression and the Attributional Style Questionnaire. Results: Time 1 attributions predicted increased levels of depression symptoms at Time 2 after perceived pain and disability were controlled: Time 1 depression symptoms were unrelated to Time 2 attributions. Cross-lagged correlation comparisons revealed statistical dominance for attribution-depression relationships relative to depression-attribution relationships. Conclusions: Results support cognitive diathesis conceptualizations of depression and support cognitive-behavioral treatments for depression in RA. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
55.
Analysis of plume mixing in the annulus of a pressurized water reactor (PWR) are presented. The plume mixing analysis is based on a simple two-dimensional model that accounts for the surrounding flow and confinement. A correlation for entrainment is presented and comparison with experiment is made.Mixed convection resulting from downflow between parallel heated plates is studied experimentally. The experimental system used to obtain the data is described with the scaling rationale for choosing the working fluid. Heat transfer results are presented in terms of a Nusselt number and a correlation is given. Results show an enhancement in heat transfer with increasing GrDh/ReDh2 due to an increase in turbulence intensity associated with the buoyant wall layer. The correlation obtained for GrDh/ReDh2 < 2.29 was found to be NuDh/NuDh,0 = 1 + 2.93 (GrDh/ReDh2)0.54, where where NuDh,0 is given by the Dittus-Boelter correlation. Use of this correlation for GrDh/ReDh2 > 2.29 is not recommended due to an observed flow bifurcation in this neighborhood. 相似文献
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Competitive snoopy caching 总被引:8,自引:1,他引:8
In a snoopy cache multiprocessor system, each processor has a cache in which it stores blocks of data. Each cache is connected to a bus used to communicate with the other caches and with main memory. Each cache monitors the activity on the bus and in its own processor and decides which blocks of data to keep and which to discard. For several of the proposed architectures for snoopy caching systems, we present new on-line algorithms to be used by the caches to decide which blocks to retain and which to drop in order to minimize communication over the bus. We prove that, for any sequence of operations, our algorithms' communication costs are within a constant factor of the minimum required for that sequence; for some of our algorithms we prove that no on-line algorithm has this property with a smaller constant.A preliminary and condensed version of this paper appeared in theProceedings of the 27th Annual Symposium on the Foundations of Computer Science, IEEE, 1986.This author received support from an IBM doctoral fellowship, and did part of this work while a research student associate at IBM Almaden Research Center. 相似文献
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Larry M. Bendele Nian Z. Sun 《润滑油》2007,22(1):11-14
Rebuilt engine "break - in" is the most critical period for long - term durability for a fiat - tappet valvetrain. Zinc dialkyl dithio phosphate (ZDDP) has proven to be a cost - effective engine oil additive for anti - wear protection and oxidation resistance. But, tightening exhaust emission standards are requiring modem lubricants to have reduced levels of ZDDP additives. If the valvetrain break- in is successfully completed, then modem low- phosphorus lubricants can be used with confidence at subsequent oil change service intervals. 相似文献
60.
The constraint-wrench analysis of mechanisms, with focus on parallel robots, is the subject of this paper. Although the method proposed here can be generalized for parallel robots with multiple-loop kinematic chains, here, single-loop chains are targeted. To this end, a novel representation of the constraints imposed by the kinematic pairs is introduced. With this representation, the constraint matrix of a mechanism is readily derived. For the calculation of the constraint wrenches, by means of the constraint matrix and based on the Newton–Euler formulation, a new procedure is introduced. As a case study, the constraint wrench analysis of the McGill Schönflies Motion Generator (SMG), while undergoing a test cycle adopted by the industry, is conducted. 相似文献