三峡库区生态经济区用地结构演变及驱动机制——以梁平县为例

根据1999～2007年土地利用统计、社会经济资料,借助信息熵原理及马尔科夫转移矩阵模型对梁平县土地利用结构动态演变进行了实例分析。结果表明,梁平县土地利用结构信息熵H经历了3个阶段：1999～2002年持续上升阶段、2002～2003年急速回落阶段及 2003～2007年波动阶段,土地利用结构无序程度发展态势不明显,均衡度变化与信息熵相似。用地类型主要由耕地转向林地、交通用地、居民点及工矿用地。定性分析了影响该县用地结构动态演变的政治经济政策,并利用主成分分析法对经济社会主要驱动因子进行了分析与探讨,得出影响该县用地结构动态演变的主要驱动力为：政治经济政策、经济发展。最后依据分析结果对梁平县未来发展做出定位：特色农业县--重点发展农林产品加工及文化生态旅游。     

Effects of low concentration biodiesel blends application on modern passenger cars. Part 3: Impact on PAH, nitro-PAH, and oxy-PAH emissions

This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions.     

The impact of state level behavioral regulations on traffic fatality rates

Introduction

A state by year panel is analyzed to simultaneously explore the statistical correlation between state level traffic fatality rates and state level behavioral regulations regarding teen licensing, seat belt use, and driving under the influence (DUI) in a model that also controls for other correlates.

Method

By including measures of all three of these policies, the estimated policy effects should not be overstated due to underspecification bias. The panel includes the 48 contiguous U.S. states for the time period from 1999 through 2003. State fatality rates are measured as fatalities per million miles traveled. Measures of state policies regarding traffic safety related behavior are based on information gathered by the Insurance Institute for Highway Safety. Estimates are calculated via a time fixed effects model that uses the double-log form to allow for interaction effects between the independent variables.

Results

Least squares estimates indicate that, on average, more restrictive graduated teen licensing and DUI policies significantly reduce traffic fatality rates, while stricter seat belt enforcement policies have a statistically insignificant negative impact on fatality rates.     

Emotions drive attention: Effects on driver’s behaviour

Music is the favourite activity while driving. However, very few studies have investigated its impact on driving performances. This study was designed to assess the effect of music’s emotional valence on driving behaviour. Happy, sad and neutral music excerpts were alternated with no-music phases while driving in a simulator. Results showed that happy music distracted drivers the most as their mean speed unexpectedly decreased and their lateral control deteriorated. Sad music influenced drivers in a different way as they drove slowly and kept their vehicle in its lane. These findings were discussed within the framework of attentional orienting and emotions.     

Sandy desertification change and its driving forces in western Jilin Province, North China

This paper investigates the sandy desertification change between 1986 and 2000 in the western Jilin province, North China. Land use and land cover data were obtained from Landsat TM data by using a supervised classification approach. We summarized the total area of desertified land by each county, as well as the area for each of the four categories of desertified land. The changes of different types of land use and land cover between 1986 and 2000 were calculated and analyzed. Taking Tongyu and Qianan as examples, both human and natural driving forces of the sandy desertification were analyzed. Our analyses indicate that the material sources and windy, warm and dry climate are the immanent causes of potential land desertification, while the irrational human activities, such as deforestation, reclaiming and grazing in the grassland, are the external causes of potential land desertification. However, rational human activities, such as planting trees and restoring grassland can reverse the land desertification process. Furthermore, the countermeasures and suggestions for the sustainable development in ecotone between agriculture and animal husbandry in North China are put forward.     

干旱灾害对江西省农业生产的影响及其对策

江西是农业大省,是国家重要的粮食主产区。近10 a来江西省干旱发生频繁,导致农业生产损失严重,威胁到农业的可持续发展。基于历史文献与资料,结合江西省农业厅的农业灾情调查数据和干旱指数最高的星子县、都昌县调研数据,着力分析近10 a来江西省的干旱状况及其对农作物生产的影响,探讨农业干旱灾害的成因。研究结果表明:江西干旱灾害以秋旱为主,近10 a年对江西的粮食和棉花生产造成重大损失,尤其是鄱阳湖区地区;江西农业干旱灾害的主要成因包括降水分布不均匀、红壤持水能力低、水利设施年久失修、植被结构破坏和易改变水文过程的大型水利设施建设。最后针对农业干旱灾害的主要成因,提出了减轻干旱灾害对农业生产不利影响的对策     

巢湖流域土地景观格局变化及生态风险驱动力研究

健康的流域生态系统是区域经济社会可持续发展的重要基础。探讨流域土地景观格局变化及生态风险驱动机制有助于生态系统状况诊断与风险来源认识,为有效制定生态风险管控措施提供决策依据。应用空间信息技术平台及计量分析方法,探讨了基于县域行政单元的快速城市化阶段巢湖流域土地景观格局变化及生态风险驱动力。研究表明:(1)2000~2013年,巢湖流域土地景观类型变化表现出农地、林地、水体景观面积下降,建设用地景观面积显著增加的趋势;流域景观水平上多样性和均匀度呈下降、优势度呈上升趋势,景观空间异质性下降;(2)近15 a来,巢湖流域9个行政单元内生态风险均呈上升趋势,生态风险整体恶化,需加强对流域生态风险上升的管控;(3)生态风险驱动力分析表明,快速城市化阶段巢湖流域生态风险的主要驱动因子为第二产业值、城市化率、人口密度和固定资产投资,而人均GDP的增加在一定程度上会降低生态风险水平。     

What’s in a name? Drivers’ perceptions of the use of five SAE Level 2 driving automation systems

Introduction: Automobile manufacturers are developing increasingly sophisticated driving automation systems. Currently, the highest level of automation available on the market is SAE Level 2, which provides sustained assistance for both lateral and longitudinal vehicle control. The purpose of this study was to evaluate how drivers’ perceptions of what behaviors secondary to driving are safe while a Level 2 system is operating vary by system name. Methods: A nationally representative telephone survey of 2005 drivers was conducted in 2018 with questions about behaviors respondents perceived as safe while a Level 2 driving automation system is in operation. Each respondent was asked about two out of five system names at random for a balanced study design. Results: The name “Autopilot” was associated with the highest likelihood that drivers believed a behavior was safe while in operation, for every behavior measured. There was less variation observed among the other four SAE Level 2 system names when compared with each other. A limited proportion of drivers had experience with advanced driver assistance systems and fewer of these reported driving a vehicle in which Level 2 systems were available. Drivers reported that they would consult a variety of sources for information on how to use a Level 2 system. Conclusions: The names of SAE Level 2 driving automation systems influence drivers’ perceptions of how to use them, and the name “Autopilot” was associated with the strongest effect. While a name alone cannot properly instruct drivers on how to use a system, it is a piece of information and must be considered so that drivers are not misled about the correct usage of these systems. Practical Applications: Manufacturers, suppliers, and organizations regulating or evaluating SAE Level 2 automated driving systems should ensure that systems are named so as not to mislead drivers about their safe use.     

Validation of the driver ecological glare test

IntroductionThe present study proposes to validate the Driver Ecological Glare Test (DEGT), a test developed to measure the benefit of a headlight glare Advanced Driver Assistance System (ADAS), by comparing it to a laboratory glare test. Method: Twenty-four participants, aged from 55 to 70 years, were recruited to complete a visual examination, including monocular halo size measurement for both eyes using Vision Monitor device (MonCv3; Metrovision). An on-field evaluation took place at night at the UTAC CERAM test track to obtain disability glare measures using the DEGT. Results: A significant correlation was found between the two glare tests and Bland-Altman analysis reveals a good agreement with a bias of 73.7 arcmin between the halo size measurements obtained from the DEGT and Vision Monitor. The results of the present study demonstrate that the DEGT is a valid method to test halo size and is adapted to evaluate the benefits of an antiglare device for drivers in an ecological situation.     

山东省耕地变化动态平衡研究

山东省耕地资源总量虽在近几年相对增加,但总体仍呈下降趋势,且人均耕地面积下降速度更快,耕地资源状况不容乐观。目前全省各地市耕地总量变化的动态平衡程度不一,德州市是耕地资源动态平衡相对最好的地市,其次为青岛、枣庄和泰安市,莱芜市耕地资源动态平衡状况较差。利用主成分分析方法的计算结果表明,经济活动、社会人口和农业科技发展水平等因素为影响山东省耕地数量变化的主要驱动因子;在以上研究的基础上,预测了山东省人口承载力和2010年粮食短缺情况。