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71.
Evans SA Elliott JM Andrews LM Bartlett PN Doyle PJ Denuault G 《Analytical chemistry》2002,74(6):1322-1326
Mesoporous (H(I)-ePt) platinum microelectrodes electrodeposited from the hexagonal (H(I)) lyotropic liquid crystalline phase are shown to be excellent amperometric sensors for the detection of hydrogen peroxide over a wide range of concentrations. Good reproducibility, high precision, and accuracy of measurements are demonstrated. Mesoporous microelectrodes retain the high rates of mass transport typical of conventional microelectrodes, and their high real surface area greatly enhances their catalytic activity. This unique combination of properties overcomes the limitations of previous amperometric hydrogen peroxide sensors and yields outstanding qualitative and quantitative results. 相似文献
72.
Crisis management logic suggests that planning and preparing for crisis should be a vital part of institutional and policy toolkits. This paper explores the difficulties in translating this ideal into practice. It focuses on four key difficulties. First, crises and disasters are low probability events but they place large demands on resources and have to compete against front‐line service provision. Second, contingency planning requires ordering and coherence of possible threats, yet crisis is not amenable to being packaged in such a predictable way. Third, planning for crisis requires integration and synergy across institutional networks, yet the modern world is characterised by fragmentation across public, private and voluntary sectors. Fourth, robust planning requires active preparation through training and exercises, but such costly activities often produced a level of symbolic readiness which does not reflect operational realities. Finally the paper reflects on whether crisis preparedness is a ‘mission impossible’, even in the post‐9/11 period when contingency planning seems to be an issue of high political salience. 相似文献
73.
Using the recorded response at two vertical array sites, the SimSoil model presented in the companion paper is evaluated. The SimSoil model, which describes the small strain nonlinear behavior of granular materials, is implemented as a material model in AMPLE2000, a nonlinear, one-dimensional site response analysis code. Shear wave velocity profiles and laboratory test data available for both the La Cienega site, which was instrumented over 250?m, and the Lotung site, which was instrumented over 47?m, were used to determine SimSoil model parameters. Predictions from AMPLE2000 are compared with the measured response at several elevations for earthquakes that resulted in both nonlinear and nearly linear soil behavior. Using the available laboratory data and known input motions, the predictions of the response at these sites matched the recorded response well for varied magnitudes of shaking with a single set of parameters for each site. 相似文献
74.
K. Yamaura Q. Huang R.W. Erwin J.W. Lynn R.J. Cava 《Journal of Low Temperature Physics》1999,117(3-4):849-853
The crystal structure of Sr
2
Y
0.8
Ca
0.2
Co
2
O
6
is orthorhombic below 270 K (Immm, a = 3.84029(7) Å, b = 3.80691(6) Å and c = 19.4980(3) Å at 20 K), transformed from tetragonal (I4/mmm, a = 3.82765(6) Å and c = 19.5795(3) Å) at 295 K. The crystal structure distortion is accompanied by an anomalous temperature dependence of the degree of buckling of the CoO
2
plane and is correlated with the development of anisotropic antiferromagnetic ordering of magnetic moments (2.93(2)
B
per Co at 20 K). A magnetically glassy state below about 35 K and variable range hopping conduction below about 64 K for
were found by magnetic susceptibility and electrical resistivity measurements. 相似文献
75.
Lynn Crawford Peter Morris Janice Thomas Mark Winter 《International Journal of Project Management》2006,24(8):722
The EPSRC funded Rethinking Project Management Network produced several insights into new directions for project management theory and practise, highlighting gaps between current theory and practise in several areas. This paper reviews the discussions around project management practitioner development that arose out of this rethinking process where project management is seen as growing from a predominantly technical skill-set to a broader practise of reflectively managing the things needed to provide a successful project outcome. In particular, the paper identifies and addresses the challenges of developing competent project managers in a world exhibiting increasingly complex project challenges, and when skilled resources at all levels are often increasingly scarce. We provide examples of practical and academic initiatives that are designed to address these challenges: internal assessment and development programs, reflective practice thesis, and distance-based critical management MBA. We conclude by speculating on some of the further challenges in developing reflective practitioners that have yet to be resolved. 相似文献
76.
Hoffman James E.; Houck Michael R.; MacMillan Frank W. III; Simons Robert F.; Oatman Lynn C. 《Canadian Metallurgical Quarterly》1985,11(1):50
Investigated the role of limited capacity processes in the detection of automatic targets in a dual-task paradigm using both behavioral and event-related potential (ERP) measures. Six right-handed undergraduates served as Ss. An automatic detection task was paired with another concurrent discrimination while the relative importance of each task was systematically varied. The resulting performance operating characteristic showed that both the speed and accuracy of automatic detection responses were affected by the allocation of attention. Reductions in the accuracy of each task were accompanied by reductions in the amplitude of a late-positive component of the ERP (P300). The latency of the P300 component elicited by automatic targets was increased in dual-task conditions. A comparison of behavioral and ERP measures suggested the involvement of 2 separate limited-capacity processes in automatic detection: one concerned with the formation of an episodic representation of target occurrence and the other with the execution of rapid motor responses. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
Effective Hamiltonian for the superconducting Cu oxides 总被引:1,自引:0,他引:1
78.
MG Friedrich O Strohm J Schulz-Menger H Marciniak FC Luft R Dietz 《Canadian Metallurgical Quarterly》1998,97(18):1802-1809
BACKGROUND: The course of tissue changes in acute myocarditis in humans is not well understood. Diagnostic tools currently available are unsatisfactory. We tested the hypothesis that inflammation is reflected by signal changes in contrast-enhanced magnetic resonance imaging (MRI). METHODS AND RESULTS: We assessed 44 consecutive patients with symptoms of acute myocarditis. Nineteen patients met the inclusion criteria revealing ECG changes, reduced myocardial function, elevated creatine kinase, positive troponin T, serological evidence for acute viral infection, exclusion of coronary heart disease, and positive antimyosin scintigraphy. We studied these patients on days 2, 7, 14, 28, and 84 after the onset of symptoms. We obtained ECG-triggered, T1-weighted images before and after application of 0.1 mmol/kg gadolinium. We measured the global relative signal enhancement of the left ventricular myocardium related to skeletal muscle and compared it with measurements in 18 volunteers. The global relative enhancement was higher in patients on days 2 (4.8+/-0.3 [mean+/-SE] versus 2.5+/-0.2; P<.0001); 7 (4.7+/-0.5, P<.0001); 14 (4.6+/-0.5, P<.0002); and 28 (3.9+/-0.4, P=.009) but not on day 84 (3.1+/-0.3; P=NS). On day 2, the enhancement was focal, whereas at later time points, the enhancement was diffuse. In patients with evidence of ongoing disease, the values remained elevated. CONCLUSIONS: Acute myocarditis evolves from a focal to a disseminated process during the first 2 weeks after onset of symptoms. Contrast media-enhanced MRI visualizes the localization, activity, and extent of inflammation and may serve as a powerful noninvasive diagnostic tool in acute myocarditis. 相似文献
79.
Despite the increased attention that problem-based learning has received as an appropriate pedagogical technique for educating adults for professional practice, reports that evaluate the process are rare and usually relate to professions other than nursing. A study was undertaken in order to discover the graduates' own perceptions of a problem-based learning programme and its effectiveness in preparing them for the reality of their chosen profession. Twelve practising graduate nurses who had completed the programme were interviewed according to the ethnographic method. Three categories were identified from the data: 'and all of a sudden...', which describes the transition from PBL student to staff nurse; 'not an unthinking assistant', where the characteristics that the PBL graduates believe make them different from traditionally trained nurses are described; and 'the buck stops here', which describes the sense of personal responsibility that the graduates experience in terms of their learning and actions. 相似文献
80.
EJ Shillitoe S Noonan CC Hinkle FC Marini RM Kellman 《Canadian Metallurgical Quarterly》1998,5(3):176-182
Considerable basic research, mostly in the past 20 years, has elicited greatly increased knowledge concerning the structure and function of cell adhesion molecules. Scores of individual adhesion molecules have been identified and categorized as to major structural features, ligands recognized, and pattern of expression. Recent attention has been focused on the interaction of cell adhesion molecules with intracellular components, and the role of cell adhesion molecules in mediating cell signal transduction. Ongoing efforts to develop specific pharmacological agonists and antagonists for adhesion molecules holds great promise in clinical medicine. Abciximab (Reopro), a monoclonal antibody inhibitor of the platelet integrin alpha IIb beta 3, is currently approved and available to improve vessel patency in patients undergoing angioplasty. Similar approaches to develop adhesion-based therapies to block angiogenesis, tumor progression, and/or metastasis are under development and hold promise for patients with cancer. 相似文献