Identifying Effects and Applications of Fixed and Variable Speed Limits

In Indiana, distracted driving and unexpected queues have led to an increase in the amount of back-of-queue crashes, particularly on approach to work zones. This report presents new strategies for the assessment of both transportation safety and traffic operations using crowd-sourced probe vehicle data and a speed laser vehicle re-identification scheme. This report concludes by recommending strategies for the placement of variable speed limits (VSL) adjacent to work zones and suggestions for future research

Cytomegalovirus and immune senescence: culprit or innocent bystander?

Immune senescence may be defined as the age-related reduction and dysregulation of immune function, and has been associated with increased incidence and severity of infectious diseases and with poor efficacy of prophylactic vaccines in the elderly. Several studies have demonstrated that persistent infections with Herpes viruses in general and Cytomegalovirus (CMV) in particular have a profound influence on subset distribution, phenotype and potentially also on the function of T cells in ageing individuals. The association of CMV-seropositivity and accumulation of CMV-specific CD8+ T cells with decreased survival in longitudinal studies of very elderly has fostered the hypothesis that CMV-infection may be an important causative factor for the development of immune senescence. Here, we have critically summarized the current body of evidence supporting this hypothesis, highlight some controversial issues about its relevance and mechanisms and propose areas of future research to demonstrate unequivocally whether and how persistent infections might compromise the ageing immune system

Pedestrian Traffic Signal Violations: Safety, Design, and Operational Implications

21-8200The objective of this research project is to improve pedestrian safety at signalized intersections by focusing on pedestrian signal violations: measuring behaviors, associating characteristics and locations, and identifying potential mitigation strategies. In this project, we recorded videos and collected and analyzed observational data on pedestrian crossing behaviors, specifically: 5,589 pedestrian crossing events for 47 crosswalks at 39 signalized intersections in Utah. After linking these data with information about the location and traffic signal status, we performed descriptive and statistical analyses of the assembled data to identify people, conditions, and locations with greater and lesser rates of pedestrian spatial and temporal violation behaviors. The large majority of pedestrian crossing events did not exhibit a spatial or temporal violation behavior. Nearly all pedestrians (97\u201398%) crossed in or within a few feet of the crosswalk; only 2\u20133% of crossing events happened mid-block, more than a car length away from the crosswalk. A large majority (89%) of pedestrian crossing events occurred without any time spent in the intersection against a conflicting green movement. However, about 5\u20136% of the time, there were pedestrians in the crosswalk for at least 5 seconds while a conflicting protected vehicle movement had the green light. Bivariate and multivariate statistical analyses identified various factors (pedestrian, waiting, crossing, temporal, and weather information; as well as crossing, intersection, land use, built environment, and neighborhood sociodemographic characteristics) associated with these behaviors. Based on the study\u2019s findings, we present several recommendations for treatments to improve intersection pedestrian safety and opportunities for future research

Circulating antibody and memory B-cell responses to C. difficile toxins A and B in patients with C. difficile- associated diarrhoea, inflammatory bowel disease and cystic fibrosis

C. difficile infection (CDI) is rarely reported in cystic fibrosis (CF) patients despite frequent hospitalisations and antibiotic usage. Conversely, the prevalence of CDI in inflammatory bowel disease (IBD) has received increased attention. We investigated components of the IgG-specific humoral immune response to C. difficile toxins A and B in patients with C. difficile-associated diarrhoea (CDAD), IBD patients with CDI, CF patients and healthy controls. Serum anti-toxin IgG was determined by ELISA. Circulating antigen-activated B-cells were investigated using Alexa Fluor 488-labelled toxin A and assessed by flow cytometry. Following induction of differentiation of memory B-cells, toxin A- and B-specific antibody secreting cells (ASCs) were quantified using ELISpot. We present the first data showing levels of serum anti-toxin A and B antibodies were significantly higher in patients with CF (without a history of CDI) than in CDAD patients and were stably maintained over time. Notably, the CDAD patients were significantly older than the CF patients. We also show that circulating toxin A-specific memory B-cells (IgD-negative) can be detected in CDAD patients [0.92 (0.09–1.78)%], and were prominent (5.64%, 1.14%) in two CF patients who were asymptomatic carriers of C. difficile. There was correlation between toxin A- and B-specific ASCs, with significantly higher proportions of the latter seen. In some with CDAD, high serum antibody levels were seen to only one of the two toxins. Mucosal secretion of toxin-specific IgG was detected in an additional group of IBD patients with no history of CDI. We conclude that enhanced and stable humoral immune responses to toxins A and B may protect CF and some IBD patients against CDI. The impaired ability to generate strong and/or sustained toxin-specific antibody and memory B-cell responses may increase susceptibilit