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1.
This meta-analysis examines the influence of electronic communication media on group idea generation tasks. Data from the following three areas of the brainstorming literature are synthesized to assess differences across performance variables and group member satisfaction: (1) electronic brainstorming (EBS) groups versus traditional face-to-face (FTF) interacting groups, (2) EBS groups versus nominal groups, and (3) EBS versus electronic nominal (e-nominal) groups. The results of this integration show that EBS groups are more productive and more satisfied with the interaction process than FTF groups. Additionally, large EBS groups outperformed nominal groups, whereas small nominal groups outperformed EBS groups. These findings have important implications for electronic collaboration and teamwork in both academic and organizational settings, especially given the recent proliferation of virtual teamwork. 相似文献
2.
Why do fish strand? An analysis of ten years of flow reduction monitoring data from the Columbia and Kootenay rivers,Canada 下载免费PDF全文
Stranding of fish due to flow reductions has been documented in the near shore of the Columbia and Kootenay Rivers, Canada, and can result in sub‐lethal or lethal effects on fish. Ten years (1999–2009) of monitoring data have been collected at sites below two hydro‐electric dams (Hugh‐L‐Keenleyside and Brilliant Dam) following flow reductions. A generalized linear mixed effects model analysed the probability of a stranding event in relation to environmental and operational variables including the rate of change in the water levels, the duration of shoreline inundation prior to a reduction (wetted history), the river stage, the magnitude of the reduction, distance downstream from the dam, time of day, day of year (season) and whether a site had been physically altered to mitigate stranding. The results demonstrated statistically significant effects on stranding risk from minimum river stage, day of the year and whether a site had been physically re‐contoured. The combination of investigated factors giving the highest probability of stranding was a large magnitude reduction completed in the afternoon in midsummer, at low water levels when the near shore had been inundated for a long period. This research is significant in its approach to assessing years of ecosystem scale monitoring data and using the modelling results to determine ways for these findings to be applied in regulated river management to minimize fish stranding. It also highlighted data gaps that require addressing and provides ecosystem scale results to compare with stranding studies carried out in mesocosms. © 2014 The Authors. River Research and Applications published by John Wiley & Sons Ltd. 相似文献
3.
Phase separation of poly(N‐isopropylacrylamide) solutions and gels using a near infrared fiber laser
We used a tunable near infrared fiber laser in the wavelength range of 1533–1573 nm to induce photothermal phase changes in poly(N‐isopropylacrylamide) (PNIPAM) aqueous solutions and hydrogels. The laser induces the hydrophilic to hydrophobic transition of the polymer by heating the surrounding water. We report our observations of the phase changes based on using a novel fiber backreflectance method coupled with visual cloud point measurements. At 1533 nm the phase transition was induced at the end of a single mode optical fiber with 9 mW of power at an ambient temperature of 24°C. We found that the power required to reach the lower critical solution temperature was inversely proportional to the absorption spectrum of water. In addition, phase changes in both solutions and gels occurred very rapidly (<1 s) as the laser was turned on and off. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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DV Mann MK Robinson JD Rounds E DeRosa DA Niles JS Ingwall DW Wilmore DO Jacobs 《Canadian Metallurgical Quarterly》1997,226(5):653-661
OBJECTIVE: To study the relation between blood and saline administration, postresuscitation hematocrit (Hct) level, and metabolic recovery after hemorrhagic shock. SUMMARY BACKGROUND DATA: It is generally believed that crystalloid can be substituted, in whole or in part, for blood during resuscitation of hemorrhagic shock. This is based on the belief that Hct can be safely reduced but should not fall below a critical level. METHODS: Male rats weighing 200 g were subjected to an isobaric hemorrhagic shock at a mean arterial pressure of 30 mmHg for 14 minutes, after which they were randomized to one of three resuscitation regimens. Control group (n = 36) were resuscitated by return of all shed blood. Mid-Hct (n = 39) and low-Hct (n = 60) groups were depleted of one third and one half of their circulating blood volumes, respectively, and were resuscitated with three times that volume of normal saline. Skeletal muscle intracellular energetics and pH were measured serially using 31P magnetic resonance spectroscopy at baseline, during shock, and after resuscitation. Arterial blood was sampled at the same time points. The number of surviving animals in each group at 24 hours was recorded. RESULTS: After resuscitation, surviving rats in the low-Hct group demonstrated a greater consumption of high-energy phosphocreatine stores than did the other groups (control = 0.479 +/- 0.003, mid-Hct = 0.465 +/- 0.004, low-Hct = 0.457 +/- 0.007, mean +/- standard error of the mean; p < 0.01 low-Hct vs. other groups by analysis of variance). The rats that received saline resuscitation developed a relative intracellular acidosis (control = 7.29 +/- 0.02, mid-Hct = 7.25 +/- 0.02, low-Hct = 7.23 +/- 0.02; p < 0.05 controls vs. other groups by analysis of variance). At 24 hours, the death rates were significantly different among the groups: control = 1 of 36 rats (2.8%), mid-Hct = 6 of 39 (15.4%), and low-Hct = 14 of 60 (23.3%) (p < 0.05 by chi square analysis). CONCLUSION: The oxygen-carrying capacity of resuscitation fluid has an important impact on intracellular metabolism and outcome. 相似文献
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Hong W.-P. Bhat R. DeRosa F. Hayes J.R. Chang G.-K. 《Electron Device Letters, IEEE》1991,12(6):284-286
The transport properties and device characteristics of pseudomorphic In0.4Al0.6As/InP modulation-doped heterostructures are investigated. The existence of a two-dimensional electron gas at the heterojunction was confirmed by Shubnikov-de Haas measurements. A high electron mobility transistor (HEMT) having a gate length of 1.5 μm showed extrinsic transconductances and drain current densities as high as 160 mS/mm and 300 mA/mm, respectively. The HEMT also showed a very small output conductance of less than 2 mS/mm and high gate-drain breakdown voltage of larger than 15 V. These results show the great potential of this HEMT for high-voltage gain and high-power microwave applications 相似文献
7.
A longitudinal study evaluating the degree of rotation of the bimalleolar axis of tibia and fibula at birth, 6 month, 12 months and 24 months revealed a gradual statistically significant external rotation from a mean of 4 degrees at birth to a mean of 11 degrees at 24 months. There was no correlation with the sex or race of the child or with the age at which the child began independent walking. It is concluded that this external rotation is a part of normal growth and development of the infants' lower extremities. 相似文献
8.
T Kohmoto CM DeRosa N Yamamoto PE Fisher P Failey CR Smith D Burkhoff 《Canadian Metallurgical Quarterly》1998,65(5):1360-1367
BACKGROUND: Transmyocardial laser revascularization is a new therapy for patients with refractory angina. Although clinical studies suggest that transmyocardial laser revascularization decreases angina and may improve regional blood flow, the underlying mechanisms are not elucidated. We hypothesized that one mechanism may relate to stimulation of vascular growth in laser-treated regions. METHODS: Transmyocardial laser revascularization channels were made with holmium:yttrium-aluminum garnet or carbon dioxide lasers in eight normal canine hearts; animals were sacrificed 2 to 3 weeks later and examined for vascular density and for evidence of smooth muscle proliferation. RESULTS: The original channels were infiltrated by granulation tissue with associated vascularity. Vascular growth was stimulated immediately surrounding the channel remnant as evidenced by an increase in the number of vessels (approximately twice that of the control region) and an increase in the number of vascular cells staining positive for markers of cellular proliferation. CONCLUSIONS: Transmyocardial laser revascularization leads to local vascular growth as early as 2 weeks after treatment. It remains to be determined whether this mechanism contributes to increased regional blood flow or to clinical benefits associated with this novel form of therapy. 相似文献
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Aptamer-polyelectrolyte microcapsules are prepared for potential use as triggered delivery vehicles and microreactors. The hollow microcapsules are prepared from the sulforhodamine B aptamer and the polyelectrolytes poly(allylamine hydrochloride) and poly(sodium 4-styrene-sulfonate), using layer-by-layer (LbL) film deposition templated on a sacrificial CaCO(3) spherical core. Scanning electron microscopy and confocal microscopy confirm the formation of spherical CaCO(3) cores and LbL-aptamer microcapsules. Colocalization studies with fluorescently-tagged aptamer and sulforhodamine B verify the ability of the aptamer to recognize its cognate target in the presence of the K(+) ions that are required for its characteristic G-quadruplex formation. Fluorescence recovery after photobleaching studies confirms a significant difference in the permeability of the aptamer-polyelectrolyte microcapsules for the sulforhodamine B dye target compared to control microcapsules prepared with a random oligonucleotide. These results suggest that aptamer-based 'smart' responsive films and microcapsules could be applied to problems of catalysis and controlled release. 相似文献