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61.
During the past decade, the invasive Phragmites australis (common reed) has established itself along beaches of the Great Lakes, causing detrimental impacts to both the natural ecological integrity of the shoreline and the recreational value of beaches. The herbicide Roundup®, containing the active ingredient glyphosate, was applied to Phragmites along a beach on the southern shore of Georgian Bay, Canada, to eradicate the Phragmites which was destroying the natural beach ecosystem. Groundwater and lake water were tested to determine if glyphosate enters the groundwater and lake at the beach and how long glyphosate will persist. Two days after application, the geometric mean concentration of glyphosate in the groundwater below the Phragmites was 0.060 μg/L with a maximum of 12.50 μg/L. Concentrations rapidly declined over the next two to three weeks to below minimum detection limits (< 0.020 μg/L). Glyphosate was also detected in the nearshore lake water with concentrations peaking at a geometric mean of 0.14 μg/L one week after application, and declining to 0.039 μg/L four weeks after application. Concentrations of glyphosate never exceeded the Canadian water quality guideline for the protection of aquatic life (65 μg/L) in either the groundwater or lake water. An approximate half-life for the dissipation of glyphosate by degradation and dilution/flushing as groundwater flows toward the lake, assuming a first order kinetic reaction, yielded a half-life of 3.5 during the 4 weeks after the herbicide was applied. The application of Roundup® resulted in an 90% reduction in the size of the stand of Phragmites. 相似文献
62.
Barbara Natalie Unger Hans Georg Gemünden Monique Aubry 《International Journal of Project Management》2012
Project portfolio management offices (PPMOs) are a subset of project management offices (PMOs) that handle collections of multiple single projects and programmes, i.e. portfolios. PPMOs are centralised organisational units that cater to the demands of various stakeholders by performing specialised tasks. They are initiated by their organisation's leadership in response to increasing management challenges originating from project portfolios. Although there has been considerable research on PMOs in general, not only a clear understanding of multi-project PMOs' activity patterns set in specific contexts like project portfolio management, but also both existence and mode of multi-project PMOs' contribution to successful performance are still lacking. By quantitatively analysing PPMOs in 278 portfolios, we identify three different activity patterns, which are interpreted as distinctive roles. We show a significant positive effect of PPMOs' coordinating and controlling roles on performance in terms of project portfolio management quality, which is a predictor of portfolio success. 相似文献
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64.
Ellis R.D. Meitzler T.J. Witus G. Sohn E. Bryk D. Goetz R. Gerhart G.R. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2000,30(3):336-346
The visual task of detecting an approaching vehicle was modeled with a neurophysiologically motivated computational vision model, the National Automotive Center-visual perception model (NAC-VPM). The scientific literature documenting age-related changes in early vision was reviewed in relationship to the components of the NAC-VPM, and the model was fit to laboratory data from older observers. The model fit the older observers' data adequately, particularly when the data was partitioned into subsets based on viewing conditions. Model fits were compared to calibrations based on younger observers' data. The calibrations based on older observers were substantially different from calibrations based on younger observers, indicating that the model can capture age-related differences in visual perception. When calibrated to the older adults' data, the model successfully predicted conditions under which vehicle detection was particularly difficult for older adults 相似文献
65.
Tsai Jessica Chia-Chin; Knoblich Günther; Sebanz Natalie 《Canadian Metallurgical Quarterly》2011,37(5):1407
According to ideomotor theories, perceiving action effects produced by others triggers corresponding action representations in the observer. We tested whether this principle extends to actions performed by externally controlled limbs and tools. Participants performed a go–no-go version of a spatial compatibility task in which their own actions resulted in the movement of a limb or tool, whereas a second, externally controlled limb or tool was seen performing a complementary go–no-go task. Spatial compatibility effects, indicating inclusion of the externally controlled effector in action planning, were observed when the externally controlled limb was identical to the controlled limb (Experiment 1) and when actions of limbs and tools (Experiment 2) or pairs of tools (Experiment 3 and 4) were combined according to participants' motor experience. When participants acted together, controlling a tool each, spatial compatibility effects occurred regardless of motor experience (Experiment 5). These findings demonstrate that (a) externally controlled tool actions are included in action planning and (b) social context modulates how externally controlled actions are mapped onto action representations. Implications of these findings for theories of perception–action links and object processing are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
66.
Natalie Chun 《国际水资源开发杂志》2014,30(4):662-679
Pricing policies can serve as a low-cost and effective tool for increasing access to water and sanitation services among poor households while allowing the provider to recover costs. An empirical model is applied to contingent-valuation survey data for water services in Cebu, Philippines. Pricing policies that utilizes a low one-time connection fee and differentiates tariffs based on wealth results in a 3 to 9-fold increase in water services access by poor households over the base pricing policy. The results provide evidence that price-discrimination techniques can be important tools toward achieving greater coverage and financial solvency of important services. 相似文献
67.
Glass-Related Injuries in Oklahoma City Bombing 总被引:2,自引:0,他引:2
H. Scott Norville Natalie Harvill Edward J. Conrath Sheryll Shariat Sue Mallonee 《Canadian Metallurgical Quarterly》1999,13(2):50-56
When a terrorist bomb explodes in an urban area, it produces devastating effects, including structural and nonstructural damage to buildings, injuries, and deaths. Numerous injuries in explosions result directly and indirectly from window glass failure. Direct glass-related injuries occur when glass shards flying and falling from fractured windows cause lacerations and abrasions. Secondary glass-related injuries occur when the shock front of the blast wave passes into buildings through fenestrations vacated by fractured glazing. The Oklahoma city bombing killed 167 people and caused numerous injuries. Most of the deaths and many of the injuries occurred in the Alfred P. Murrah Federal Building, the target of the bomb. This event focused the attention of the engineering and security communities on two major issues: the prevention of progressive structural collapse and the design of blast-resistant glazing. This paper discusses glass-related injuries that occurred away from the Alfred P. Murrah Federal Building in Oklahoma City. In particular, it provides information concerning locations of glass-related injury victims in other buildings with respect to their position in proximity to outside walls with glazing. Location data indicate that more than one-quarter of the glass-related injury victims in buildings were positioned within 1.5 m (5 ft) of a wall with glazed fenestrations and nearly one-half of the glass-related injury victims were positioned within 3.0 m (10 ft) of a wall with glazed fenestrations. In addition to suffering lacerations and abrasions, a large number of victims in buildings suffered hearing damage because glazing that failed to maintain closure of fenestrations exposed them to the shock front of the blast wave. Consideration of the injury data justifies a requirement for design of blast-resistant glazing to protect building inhabitants. 相似文献
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69.
CA Kirker-Head TN Gerhart R Armstrong SH Schelling LA Carmel 《Canadian Metallurgical Quarterly》1998,(349):205-217
Middiaphyseal 2.5-cm segmental defects in the right femurs of 12 sheep were stabilized with stainless steel plates and implanted with (1) 2 mg recombinant human bone morphogenetic protein 2 and poly[D,L-(lactide-co-glycolide)] bioerodible polymer with autologous blood (n = 7), (2) 4 mg recombinant human bone morphogenetic protein 2 and poly[D,L-(lactide-co-glycolide)] and blood (n = 3), or (3) poly[D,L-(lactide-co-glycolide)] and blood only (n = 2). Bone healing was evaluated for 1 year using clinical, radiographic, gross pathologic, and histologic techniques. Union occurred in three sheep in Group 1, two in Group 2, and none in Group 3. In the animals that healed, new bone first was visible radiographically between Weeks 2 and 6 after implantation; new bone mineral content equaled that of the intact femur not surgically treated by Week 16; recanalization of the medullary cavity approached completion at Week 52; and at necropsy the surgical treated femurs were rigidly healed, the poly[D,L-(lactide-co-glycolide)] was resorbed completely, and woven and lamellar bone bridged the defect site. In two Group 1 sheep euthanized at Weeks 2 and 6, polymer particles were permeated by occasional multinucleated giant cells. Some plasma cells, lymphocytes, and neutrophils were present locally. The poly[D,L-(lactide-co-glycolide)] tended to fragment during surgical implantation. Despite these observations, the recombinant human bone morphogenetic protein 2/poly[D,L-(lactide-co-glycolide)] implant was able to heal large segmental bone defects in this demanding model. 相似文献
70.
业务模式的缺陷、运营商的谨慎及标准的冲突阻碍了手机电视发挥其真正的潜力。由于媒体公司很快就获得了其移动性法案(或有或无电信公司的支持),因此这项技术将引领用户驱动的视频革命。 相似文献