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61.
David R. Purkey Wesley W. Wallender Graham E. Fogg Bellie Sivakumar 《Canadian Metallurgical Quarterly》2004,130(6):451-459
In order to rigorously examine near surface, field to field interactions between irrigation management regimes and a shallow fluctuating water table, an enhanced deforming finite element (DFE) model was recently developed. The enhanced DFE model, through a process of iteration within each time step, avoids making common assumptions regarding the changing geometry of an aquifer free surface. This paper demonstrates the usefulness and effectiveness of the model by employing it to an irrigated region in the western San Joaquin Valley, Calif., where shallow subsurface tile drains have been installed to control shallow water tables. By virtue of the problems created by the need to dispose off the drainage water, this region has been the focus of several important regional scale modeling exercises, which have evaluated the utility of management strategies, such as source control, groundwater pumping, and land retirement. By refining the focus of the analysis, the enhanced DFE model is found to be able to show that both sources control and managed pumping could be more effective drainage control strategies than predicted based on the results of regional models. 相似文献
62.
Akira Masutani Tony Roberts Bettina Schüller Akio Yasuda Akira Sakaigawa Graham Cross David Bloor 《Journal of the Society for Information Display》2004,12(3):301-307
Abstract— A novel preparation method for dichroic dye‐doped polymer‐dispersed liquid crystals has been developed. This was achieved by creating a porous polymer matrix first by washing out the liquid crystal from a polymer‐dispersed liquid crystal (PDLC), which is then refilled with dye‐doped liquid crystal. Optimizing the liquid crystal used in the refilling results in decreased turn‐on voltage and faster response time. Poster‐standard reflectivity and newspaper‐standard contrast was demonstrated with a 3.8‐in. QVGA reflective TFT display with a drive voltage of 10 V. 相似文献
63.
John E. Rash Timothy J. A. Johnson C. Sue Hudson F. Dennis Giddings William F. Graham Mohyee E. Eldefrawi 《Journal of microscopy》1982,128(2):121-138
Three methods are described for direct post-fracture, post-shadow labelling of individual classes of intramembrane particles (IMPs) in freeze-fracture replicas of biological membranes. The P-face IMPs corresponding to the acetylcholine receptor complexes (AChRs) of vertebrate neuroeffector junctions are identified by post-replication labelling with ferritin-antibody complexes and with neurotoxin-biotin-avidin-colloidal gold affinity ligands. (The freeze-etch nomenclature of Branton et al., 1975, is used in this report.) These post-shadow labelling techniques resemble conventional en bloc labelling techniques except that the labelling reagents must penetrate a thin but discontinuous layer of platinum superimposed on the molecules of interest. In the ‘sectioned labelled-replica technique’, the replicated and labelled tissues are stained, embedded in plastic and sectioned parallel to the replica-tissue interfaces. In the direct ‘labelled-replica techniques’, the replicated and labelled samples are freeze-dried or critical point dried, the labelled surfaces are stabilized by carbon coating, and the underlying tissues are dissolved, allowing the labelled-replicas to be examined as conventional freeze-fracture replicas. The unshadowed side of each AChR IMP is shown to retain sufficient biochemical information to permit both immunospecific and neurotoxin specific labelling despite formaldehyde fixation, freezing, fracturing, platinum shadowing, and thawing in aqueous media. A new mixed ferricyanide-osmium staining method reveals electron opaque structures spanning the membrane bilayer in the same size, number and distribution as the labelled IMPs. These experiments demonstrate the feasibility of identifying individual IMPs in freeze-fracture replicas and may allow the identification of specific membrane lesions in human disease. 相似文献
64.
Contends that the glory of psychotherapists' "tree of psychology" is that its roots are absolutely philosophical and, therefore, limitless in scope and devoid of absolute proofs. The trunk of this tree is a solid and substantial store of scientific and empirical data. The branches bear a multitude of flowers, many of which are not quite substantial; not made to endure the critical climate of a questioning world. Ultimately, however, these flowers contain the germinating factor, that which allows human knowledge the possibility of continued growth and rejuvenation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Smith Laura; Constantine Madonna G.; Graham Sheila V.; Dize Chelsea B. 《Canadian Metallurgical Quarterly》2008,39(3):337
Multicultural competence has become a mainstay within the training of professional psychologists, yet important areas within this framework remain to be more fully addressed. In particular, the dynamics of contemporary forms of racism have largely gone unexplored, depriving psychologists of clear direction in exploring the deepest levels of racist influences in their work. This qualitative analysis sought to shed light into this area by studying White people's experiences of race and racism. Although most affirmed the existence of racism, it was "spun" by most White participants--in other words, interpreted to their own advantage-into a problem that lies outside the scope of their own lives and responsibilities. Implications and resources for the practice and training of professional psychologists are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
The fabrication, operation, and characterization of a polymer-based rectilinear ion trap mass analyzer is discussed. A novel, fast prototyping technique, stereolithography (SLA)-based fabrication, traditionally reserved for end use production parts and to fabricate master molds for rubber products, is applied here as a tool to create precise, arbitrary geometries. Taking full advantage of the SLA methodology, an open corner, polymer-based ion trap has been fabricated and tested. The use of a custom resin, Nanoform 15120 (DSM Somos, New Castle, DE), has resulted in a polymer with high heat deflection temperature and greater structural stability at higher temperatures and lower capacitance. The mass analyzer was mounted in a polymer holder and tested in a custom vacuum system using modified LCQ Duo (Thermo Fisher Corp.) electronics. The resolution, mass/charge range, and MS/MS capabilities were examined using electrospray ionization as well as atmospheric pressure chemical ionization. In the course of this study, three traps of different sizes were fabricated, beginning with a "full size" device measuring 10 x 8 x 50 mm. The next two traps were scaled down by linear factors of a half and a third. SLA is shown to allow fabrication of light, small rectilinear ion traps, which are less expensive and have the same performance as traditional machined devices of the same size. In addition, smaller traps can be built just as easily, and they show unit mass resolution to mass 300, tandem mass spectrometry capabilities, and low power consumption. 相似文献
67.
This article analyzes the possibilities of applying Continuous Improvement principles to the management and maintenance of academic library websites. Current practice is mapped onto Continuous Improvement principles, with evidence distilled from a United Kingdom national survey of academic library web practitioners. The survey data informs a website organizational framework and operational model. The framework describes the setting within which library websites are managed, while the model focuses on library specific aspects to the management and development of their site. 相似文献
68.
In this paper, a new dynamic model describing the epileptic seizure initiation through transition from interictal to ictal state in a brain predisposed to epilepsy is suggested. The model follows Freeman’s approach where the brain is viewed as a network of interconnected oscillators. The proposed nonlinear model is experimentally motivated and relies on changes in synaptic strength in response to excitatory spikes. This model exhibits a threshold beyond which a bifurcation toward a short-term plasticity state occurs leading to seizure onset. A resulting explanatory assumption is that when considering epilepsy, brain regions are characterized by abnormally low thresholds toward short-term synaptic plasticity. It is shown by simulation that the proposed model enables some experimentally observed qualitative features to be reproduced. Moreover, a preliminary discussion on the impact of the underlying assumptions on the fundamental issue of seizure control is proposed through an EEG based feedback control scheme. 相似文献
69.
This study examined directly the impact of various factors associated with driving on ‘A-class’ roads in the United Kingdom (specifically length of platoon, proportion of heavy goods vehicles (HGVs), speed and opportunities for overtaking) on self-reported frustration and overtaking intentions. The impact of situational variables (being under time pressure, and time behind a slower moving platoon) were also examined, as was the association between frustration and self-reported overtaking intentions. 183 members of the public from the areas around Perth and Inverness, Scotland took part in the study. Participants viewed simulated ‘driver’s viewpoint’ clips representing all the combinations of the experimental variables (except time pressure, which was a between-groups variable, and time behind platoon, which was examined separately in four specific clips). After each clip, participants responded on a paper questionnaire as to the level of frustration they would feel for a given clip, and the likelihood that at some point during the clip they would have attempted an overtake manoeuvre. The findings show that the links between traffic variables such as speed and platoon length, and behaviourally-relevant variables such as frustration and overtaking intentions, are not simple. Although there are broad and predictable effects of speed and platoon length (lower speeds and longer platoons leading to greater frustration) these are mediated by other variables, and it is not always the case that more frustration leads to more intention to overtake. Analysis of driver attitudes identified three clusters (low, medium and high risk drivers) and suggests that higher risk drivers’ levels of frustration are more affected by situational changes than those of lower risk drivers. 相似文献
70.
In the latter part of the nineteenth century and the early part of the twentieth, various attempts were made to ‘modernize’ the city of Málaga (southern Spain) in terms of structural and built environment. These efforts originated from different groups at different times and with varying degrees of success but they had, as their principal motive, a shared desire to advance the image of the city against a background of political unrest and significant economic decline from mid-nineteenth century prosperity. With this objective in mind, there was a shared perspective that the visual appearance of the city and its morphological structure had to be modernized. However, in detail, the specific schemes proposed reflected the diverse ideologies and objectives of their chief protagonists although the generic term Málaga Moderna came to be applied to a wide range of different proposals. This article will examine the development of these key actor groups and their varying impact on the city's urban form. 相似文献