Evaluation of the Scottsdale Loop 101 automated speed enforcement demonstration program

Speeding is recognized as a major contributing factor in traffic crashes. In order to reduce speed-related crashes, the city of Scottsdale, Arizona implemented the first fixed-camera photo speed enforcement program (SEP) on a limited access freeway in the US. The 9-month demonstration program spanning from January 2006 to October 2006 was implemented on a 6.5 mile urban freeway segment of Arizona State Route 101 running through Scottsdale. This paper presents the results of a comprehensive analysis of the impact of the SEP on speeding behavior, crashes, and the economic impact of crashes. The impact on speeding behavior was estimated using generalized least square estimation, in which the observed speeds and the speeding frequencies during the program period were compared to those during other periods. The impact of the SEP on crashes was estimated using 3 evaluation methods: a before-and-after (BA) analysis using a comparison group, a BA analysis with traffic flow correction, and an empirical Bayes BA analysis with time-variant safety. The analysis results reveal that speeding detection frequencies (speeds> or =76 mph) increased by a factor of 10.5 after the SEP was (temporarily) terminated. Average speeds in the enforcement zone were reduced by about 9 mph when the SEP was implemented, after accounting for the influence of traffic flow. All crash types were reduced except rear-end crashes, although the estimated magnitude of impact varies across estimation methods (and their corresponding assumptions). When considering Arizona-specific crash related injury costs, the SEP is estimated to yield about $17 million in annual safety benefits.

自然界的四种基本相互作用力能统一吗?

<正> 一、自然界中有四种基本相互作用力关于“力”的研究是一门最古老的科学,同时也是现代最前缘的科学内容.顾名思义,力学是研究力的一门学问.宇宙间没有孤立存在的“力”,它是在物质相互作用中表现出来的.最初,人们认识“力”的概念是从生产劳动和日常生活中开始的.人们观察到力是肌肉的伸缩,汉字“力”(篆文)字本身就是人筋的象形.我国古代有人称:“力,形之所以奋也.”这也就是说“力”是一种相互作用.

Espais naturals. 'Espacios naturales'.

Presenta tres videogramas donde muestra diversos ecosistemas de Cataluña: las ciénagas del Empordà, el Montsec y el Montsant.

Entre el método y el sentimiento.

Se presenta una reflexión sobre la pedagogía amigoniana, sobre sus principios y métodos de enseñanza. La pedagogía amigoniana se basa en la 'educación de la voluntad y la educación del corazón'. A través de la educación cristiana en valores se establece una relación entre educadores y educandos sobre el cariño, el amor y la empatía.

Photoluminescence in quantum-confined SnO2 nanocrystals: Evidence of free exciton decay

Nanocrystalline SnO2 quantum dots were synthesized at room temperature by hydrolysis reaction of SnCl2. The addition of tetrabutyl ammonium hydroxide and the use of hydrothermal treatment enabled one to obtain tin dioxide colloidal suspensions with mean particle radii ranging from 1.5 to 4.3 nm. The photoluminescent properties of the suspensions were studied. The particle size distribution was estimated by transmission electron microscopy. Assuming that the maximum intensity photon energy of the photoluminescence spectra is related to the band gap energy of the system, the size dependence of the band gap energies of the quantum-confined SnO2 particles was studied. This dependence was observed to agree very well with the weak confinement regime predicted by the effective mass model. This might be an indication that photoluminescence occurs as a result of a free exciton decay process. (C) 2004 American Institute of Physics.

Estímulo ao desenvolvimento infantil: produção do conhecimento em enfermagem

Este estudo teve como objetivo identificar as ações de enfermagem para estímulo ao desenvolvimento infantil, em periódicos nacionais e internacionais, no período de 2000 a 2009. Revisão integrativa da literatura, nas bases de dados Medline e Lilacs, com análise de quinze artigos. Os resultados apontam o lúdico como essencial ao desenvolvimento infantil, devendo ser explorado pela enfermagem por meio da arte, música, brinquedos e teatro. Amenizar o estresse da hospitalização com adequação ambiental reduz o seu impacto sobre o desenvolvimento infantil. Orientar e intervir nos inter-relacionamentos são ações de enfermagem para o desenvolvimento social e comportamental infantil. Os temas abordados na literatura são fundamentais para uma prática de enfermagem no cuidado integral à saúde da criança.

Plastic Furniture: las sillas-mundo

Investigación sobre las herramientas arquitectónicas utilizadas por Charles y Ray Eames a través del estudio de la familia de mobiliario que ha recibido el nombre de Plastic Furniture