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991.
Many global challenges, including obesity, health care costs, and climate change, could be addressed in part by increasing the use of bicycles for transportation. Concern about the safety of bicycling on roadways is frequently cited as a deterrent to increasing bicycle use in the USA. The use of effective signage along roadways might help alleviate these concerns by increasing knowledge about the rights and duties of bicyclists and motorists, ideally reducing crashes. We administered a web-based survey, using Twitter for recruitment, to examine how well three US traffic control devices communicated the message that bicyclists are permitted in the center of the travel lane and do not have to “get out of the way” to allow motorists to pass without changing lanes: “Bicycles May Use Full Lane” and “Share the Road” signage, and Shared Lane Markings on the pavement. Each was compared to an unsigned roadway. We also asked respondents whether it was safe for a bicyclist to occupy the center of the travel lane. “Bicycles May Use Full Lane” signage was the most consistently comprehended device for communicating the message that bicyclists may occupy the travel lane and also increased perceptions of safety. “Share the Road” signage did not increase comprehension or perceptions of safety. Shared Lane Markings fell somewhere between. “Bicycles May Use Full Lane” signage showed notable increases in comprehension among novice bicyclists and private motor vehicle commuters, critical target audiences for efforts to promote bicycling in the USA. Although limited in scope, our survey results are indicative and suggest that Departments of Transportation consider replacing “Share the Road” with “Bicycles May Use Full Lane” signage, possibly combined with Shared Lane Markings, if the intent is to increase awareness of roadway rights and responsibilities. Further evaluation through virtual reality simulations and on-road experiments is merited. 相似文献
992.
This article provides an ethical analysis of the U.S. practice guideline update on disorders of consciousness. Our analysis focuses on the guideline’s recommendations regarding the use of investigational neuroimaging methods to assess brain-injured patients. Complex and multifaceted ethical issues have emerged because these methods alter the clinical understanding of consciousness. We address issues of false hope, patient suffering, and cost. We argue that, in spite of these concerns, there is significant benefit to using neuroimaging to assess brain-injured patients in most cases. 相似文献
993.
Patricia Ramírez-Bastida Adolfo G. Navarro-Sigüenza A. Townsend Peterson 《Biodiversity and Conservation》2008,17(10):2525-2558
The aquatic birds of Mexico include both a rich fauna of residents and a significant proportion of migratory species that
breed in Canada and the United States, yet their distribution and richness patterns remain poorly known. We developed a detailed
database of occurrences, and estimated distributions using niche modeling interpolations for 134 species associated with wetlands.
Validations of the resulting maps indicated that the niche-modeling approach yields a useful picture of aquatic bird species
distributions in the country. Richness patterns among aquatic birds differ from those for landbirds: species richness is concentrated
in coastal areas, but endemism is focused in the Transvolcanic Belt and the Altiplano. Place prioritization exercises identified
sets of areas that would maximize the protection of this diversity. 相似文献
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995.
Somatic Mutator activity expression is dependent on the strength of Cy trans-active signals in maize
B. E. Scheffler P. A. Peterson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(4):449-456
Summary Two receptor element alleles (vp-rcy and bz-rcy) that respond to the trans-active element (Cy) controlling Mutator activity were used to analyze the strength of trans-active signals from Cy elements derived from a Mutator active line. Evidence is presented that the Mutator population tested consists mainly of a class of weak Cy elements designated as Cy:Mu. When Cy:Mu element are present in only a few copies, the strength of the combined transposition signal is weak. It is only when these active elements have a high copy number that the overall transposition signal is sufficiently strong enough to elicit a high frequency of transposition events. This study seeks to investigate the nature of the trans-active signal from Cy:Mu elements. The implication of these results for molecular studies is discussed.Journal Paper No. J-13083 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA, Project No. 2381 相似文献
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999.
Data from a series of human exposures to carbon monoxide (CO) were analyzed to determine the fit to the theoretical Coburn-Forster-Kane (CFK) equation which describes CO absorption and excretion. The equation was found to predict carboxyhemoglobin (HbCO) saturations for both men and women at exercise rates ranging from sedentary to 300 kpm/min when they were exposed to steady CO concentrations of 50, 100, and 200 ppm for 0.33-5.25 h. Methods for determining values of each of the variables in the CFK equation were collected and a rational, efficient procedure for solving the equation by trial and error was outlined. The CFK equation was then used to prepare a graph, relating HbCO saturation to exposure duration and concentration, and also to describe the effect of several variables on the rate of CO uptake and equilibrium HbCO levels, important considerations in the determination of permissible public, occupational, and experimental exposure to CO. 相似文献
1000.
Sequence of an epidermal growth factor-binding protein 总被引:4,自引:0,他引:4
A cDNA clone has been isolated that corresponds to the entire translated region of the mRNA coding for the epidermal growth factor-binding protein type B. The complete nucleotide sequence and the predicted amino acid sequence of the protein were elucidated. The protein sequence was compared to some related serine proteases. This comparison supports the notion that several serine proteases suggested to be involved in the processing of precursors to polypeptide hormones and growth factors are closely related to each other. It appears that these proteases are descendants of a common ancestral gene and thus form a distinct subfamily among the serine proteases. 相似文献