Preferred modes of travel among older adults: What factors affect the choice to walk instead of drive?

Introduction

There are many factors that influence older adults' travel choices. This paper explores the associations between mode of travel choice for a short trip and older adults' personal characteristics.

Methods

This study included 406 drivers over the age of 64 who were enrolled in a large integrated health plan in the United States between 1991 and 2001. Bivariate analyses and generalized linear modeling were used to examine associations between choosing to walk or drive and respondents' self-reported general health, physical and functional abilities, and confidence in walking and driving.

Results

Having more confidence in their ability to walk versus drive increased an older adult's likelihood of walking to make a short trip by about 20% (PR = 1.22; 95% CI: 1.06-1.40), and walking for exercise increased the likelihood by about 50% (PR = 1.53; 95% CI = 1.22-1.91). Reporting fair or poor health decreased the likelihood of walking, as did cutting down on the amount of driving due to a physical problem.

Discussion

Factors affecting a person's decision to walk for exercise may not be the same as those that influence their decision to walk as a mode of travel. It is important to understand the barriers to walking for exercise and walking for travel to develop strategies to help older adults meet both their exercise and mobility needs. Impact on Industry: Increasing walking over driving among older adults may require programs that increase confidence in walking and encourage walking for exercise.     

COMPARISON OF REGRESSION AND TIME-SERIES METHODS FOR SYNTHESIZING MISSING STREAMFLOW RECORDS1

ABSTRACT: Regression and time-series techniques have been used to synthesize and predict the stream flow at the Foresta Bridge gage from information at the upstream Pohono Bridge gage on the Merced River near Yosemite National Park. Using the available data from two time periods (calendar year 1979 and water year 1986), we evaluated the two techniques in their ability to model the variation in the observed flows and in their ability to predict stream flow at the Foresta Bridge gage for the 1979 time period with data from the 1986 time period. Both techniques produced reasonably good estimates and forecasts of the flow at the downstream gage. However, the regression model was found to have a significant amount of autocorrelation in the residuals, which the time-series model was able to eliminate. The time-series technique presented can be of great assistance in arriving at reasonable estimates of flow in data sets that have large missing portions of data.     

中药生产中的综合利用途径

综合利用中药资源,开展中药生产中的废料综合利用工作,是保证中药资源永续利用的重要措施和手段。本文概述了中药生产中的综合利用及研究情况,探讨了中药生产中废料资源化技术的开发。     

MFAM模型在河流水质污染模拟及预测中的应用

文中以时间序列分析为基础，介绍了均值生成函数这一崭新概念，并且经成份因子提取分析推导建立了模拟序列的数字模型（简记为MFAM），经对黄河下游花园口断面的1988-1989年实测水质污染指标溶解氧（DO），氨氧，化学耗氧量（COD），五日生化需氧量（BOD5）等序列模拟，结果表明MFAM模型能较好地模拟河流水质污染指标的变化趋势，拟合平均误差只有5.2-6.4%，MFAM模型应用于预测1990-1991年水质污染指标变化，结果表明预测精度达85%以上，文中最后得出结论：MFAM模型应用于河流污染模拟和预测，是完全可行且十分方便。     

应用隶属函数的条件概率法综合判别雹云

本文提出应用隶属函数的条件概率法综合判别雹云。该方法把雹云和非雹云视作参数的模糊集合,因而在综合判别式中,每个参数对雹云和非雹云都有一个隶属度。利用成都市1982～1987年天气雷达回波历史资料,分别建立了全年、4～6月和7～8月的雹云等强对流天气的综合判别式,并用建立的模式对成都市1990年4～6月的7个强对流天气个例作试报检验。结果表明用该方法建立不同地区和不同季节的雹云等强对流天气综合判别式是可行的。     

估计近场地震动的统计—经验格林函数法

本文提出统计-经验格林函数法,用以估计缺乏小震记录场点在大震时的地震动时程。统计-经验格林函数的富里哀幅值谱从其它类似场地获得的小震记录的富里哀谱的衰减关系中得到,其相位谱则直接取自小震记录的相位谱。本文分别用经验格林函数法和统计-经验格林函数法,用迁安台记录到的1976年唐山地震的三次余震(M_L 5.8、M_L 5.7和M_L 5.4)的加速度记录,合成唐山地震的最大余震滦县地震(M_s 7.1)时迁安台的加速度时程曲线,合成结果说明了所提方法的可行性。     

FLOOD FREQUENCY ANALYSIS FOR SMALL WATERSHEDS IN SOUTHERN ILLINOIS1

ABSTRACT: Twenty-two gaging stations were selected for developing a regional flood frequency curve for small (area less than 2 square miles) watersheds in southern Illinois. Five probability functions were compared, and the extreme value type I function was selected to develop the regional flood curve. The curve was generated with the index flood method and also another empirical method that related the function parameters to the watershed area. Estimated peak discharges with various return periods were compared with the results obtained from multiple regression analysis.     

Estimation of the shadow prices of pollutants with production/environment inefficiency taken into account: a nonparametric directional distance function approach

This paper deals with the estimation of the shadow prices of pollutants with a nonparametric directional distance function approach, where the inefficiency involved in the production process is taken into account unlike the previous studies. The directional vector, which is critical to the estimation and subject to the criterion for an appropriate efficiency rule proposed here, is calculated by using the annual plans of power plants in terms of production and environment. In the empirical study for Korea's electric power industry during the period of 1990-1995, we find that the average shadow prices of sulfur oxides (SOx), nitrogen oxides (NOx), and total suspended particulates (TSP) are approximately 10% lower than those calculated under the assumption of full efficiency. The methodology we propose and the findings obtained in the empirical study allow us to undertake better decision-making over a broad range of environmental policy issues.     

谈森林防火中的计划火烧

计划火烧是预防森林火灾的一种有效手段,成本低,效果显著。本文详细阐述了计划火烧的意义和作用、计划火烧前的准备工作,并提出了计划火烧的注意事项及实际操作要领。     

经济体制转轨下的环境管理模式初探

党的十五大提出发展多种形式的公有制经济,在这种新形势下,环境管理如何转轨,本文进行了探讨和研究。