On Intelligent Transportation Systems and Road Congestion

Despite substantial investments in transportation infrastructures, road congestion in urban areas has not abated. While there is a growing interest among policymakers in intelligent transportation systems (ITS), the role of ITS in road congestion has not been established. To investigate the effect of ITS on road congestion, we utilized a unique dataset on traffic and ITS adoption from 99 U.S. urban areas in 2001-2008. The results from fixed-effects estimations show that ITS adoption reduces road congestion, saving an average driver 98 minutes of driving time and $38 per year. We also obtained preliminary evidence that ITS reduces carbon emissions by alleviating road congestion. Our findings extend the emerging IS literature on IT value in the public sector and the societal impacts of IT. Our study also contributes to the transportation economics literature and informs transportation policymakers by showing that ITS could be a cost-effective alternative to tackle road congestion

Design Method and Cost-Benefit Analysis of Hybrid Fiber Used in Asphalt Concrete

Fiber, as an additive, can improve the performance of asphalt concrete and be widely studied, but only a few works have been done for hybrid fiber. This paper presents a new and convenient method to design hybrid fiber and verifies hybrid fiber’s superiority in asphalt pavement engineering. Firstly, this paper expounds the design method used as its applied example with the hybrid fiber composed of lignin, polyester, and polypropylene fibers. In this method, a direct shear device (DSD) is used to measure the shear damage energy density (SDED) of hybrid fiber modified asphalts, and range and variance statistical analysis are applied to determine the composition proportion of hybrid fiber. Then, the engineering property of hybrid fiber reinforced asphalt concrete (AC-13) is investigated. Finally, a cost-benefit model is developed to analyze the advantage of hybrid fiber compared to single fibers. The results show that the design method employed in this paper can offer a beneficial reference. A combination of 1.8% of lignin fiber and 2.4% of polyester fiber plus 3.0% polypropylene fiber presented the best reinforcement of the hybrid fiber. The cost-benefit model verifies that the hybrid fiber can bring about comprehensive pavement performance and good economy

Copper binding in IscA inhibits iron-sulphur cluster assembly in Escherichia coli

© 2014 John Wiley & Sons Ltd. Among the iron-sulphur cluster assembly proteins encoded by gene cluster iscSUA-hscBA-fdx in Escherichia coli, IscA has a unique and strong iron binding activity and can provide iron for iron-sulphur cluster assembly in proteins in vitro. Deletion of IscA and its paralogue SufA results in an E. coli mutant that fails to assemble [4Fe-4S] clusters in proteins under aerobic conditions, suggesting that IscA has a crucial role for iron-sulphur cluster biogenesis. Here we report that among the iron-sulphur cluster assembly proteins, IscA also has a strong and specific binding activity for Cu(I) in vivo and in vitro. The Cu(I) centre in IscA is stable and resistant to oxidation under aerobic conditions. Mutation of the conserved cysteine residues that are essential for the iron binding in IscA abolishes the copper binding activity, indicating that copper and iron may share the same binding site in the protein. Additional studies reveal that copper can compete with iron for the metal binding site in IscA and effectively inhibits the IscA-mediated [4Fe-4S] cluster assembly in E. coli cells. The results suggest that copper may not only attack the [4Fe-4S] clusters in dehydratases, but also block the [4Fe-4S] cluster assembly in proteins by targeting IscA in cells. Copyrigh

Mitigating traffic congestion: the role of intelligent transportation systems

Despite massive investments in transportation infrastructure, traffic congestion remains a major societal and public policy problem. Intelligent transportation systems (ITS) have been proposed as a potential solution to this challenge, but their effectiveness has remained unclear in both research and practice. To understand whether and how ITS affect traffic congestion, we consolidate a unique longitudinal data set on road traffic and the deployment of a large federally supported ITS program in the United States-511 systems-in 99 urban areas between 1994 and 2014. The difference-in-differences estimates show that the adoption of 511 systems is associated with a significant decrease in traffic congestion, saving over $4.7 billion dollars and 175 million hours in travel time annually in U.S. cities. 511 systems also reduce about 53 million gallons of fossil fuel consumption and over 10 billion pounds of CO2 emissions. We offer two theoretical explanations for this effect: (i) ITS help individual commuters to make better travel decisions, and (ii) ITS help local governments to develop an urban traffic management capability. Empirical evidence supports the underlying theoretical mechanisms and shows that ITS help commuters to schedule travel more efficiently, choose better navigation routes, and optimize their worktrip transportation mode. Second, the effect of ITS is contingent on road supply and public transit services. We also find that the traffic-reducing effect of ITS is larger when commuters use more online services for traffic information and when state governments incorporate more functionalities into their 511 systems. This study contributes to the literature on IT capabilities, public-sector IT value, and the societal impact of IT, while also extending the transportation economics to IT-enabled traffic interventions. Finally, we inform policymakers of ITS as a cost-effective means to mitigating traffic congestion

Evaluation of combined prescription of rocker sole shoes and custom-made foot orthoses for the treatment of plantar fasciitis

Background: It is a routine practice to prescribe a combination of rocker shoes and custom-made foot orthoses for patients with plantar fasciitis. Recently, there has been a debate on this practice, and studies have shown that the individual prescription of rocker shoes or custom-made foot orthoses is effective in treating plantar fasciitis. The aim of this study was to evaluate and compare the immediate therapeutic effects of individually prescribed rocker sole shoes and custom-made foot orthoses, and a combined prescription of them on plantar fasciitis. Methods: This was a cross-over study. Fifteen patients with unilateral plantar fasciitis were recruited; they were from both genders and aged between 40 and 65. Subjects performed walking trials which consisted of one 'unshod' condition and four 'shod' conditions while wearing baseline shoes, rocker shoes, baseline shoes with foot orthotics, and rocker shoes with foot orthotics. The study outcome measures were the immediate heel pain intensity levels as reflected by visual analog scale pain ratings and the corresponding dynamic plantar pressure redistribution patterns as evaluated by a pressure insole system. Results: The results showed that a combination of rocker shoes and foot orthoses produced a significantly lower visual analog scale pain score (9.7 mm) than rocker shoes (30.9 mm) and foot orthoses (29.5 mm). With regard to baseline shoes, it also significantly reduced the greatest amount of medial heel peak pressure (- 33.58%) without overloading other plantar regions when compared to rocker shoes (- 7.99%) and foot orthoses (- 28.82%). Discussion: The findings indicate that a combined prescription of rocker sole shoes and custom-made foot orthoses had greater immediate therapeutic effects compared to when each treatment had been individually prescribed

Negotiating crisis in the Social Media environment: Evolution of crises online, gaining credibility offline

Purpose – The aim of this paper is to examine how crises can be triggered online, how different social media tools escalate crises, and how issues gain credibility when they transit to mainstream media. Design/methodology/approach – This exploratory study uses the multiple case study method to analyze five crises, generated online, throughout their life-cycles, in order to build analytic generalizations (Yin). Findings – Crises are often triggered online when stakeholders are empowered by social media platforms to air their grievances. YouTube and Twitter have been used to raise issues through its large user base and the lack of gatekeeping. Facebook and blogs escalate crises beyond the immediate stakeholder groups. These crises are covered by mainstream media because of their newsworthiness. As a result, the crises gain credibility offline. Mainstream media coverage ceases when traditional news elements are no longer present. Research limitations/implications – If crises are increasingly generated online, this study aims to apply a framework to manage the impact on organizations. Practical implications – How practitioners can use different new media tools to counter crises online and manage the transition of crises to mainstream media. Originality/value – This is one of the first few studies that analyses how organizational crises originate online, gain traction and get escalated onto mainstream media. Understanding what causes crises to trigger online and gain legitimacy offline will enable practitioners to engage in effective crisis management strategies