The Effects of Headlight Intensity and Clothing Contrast on Pedestrians\u27 Own Estimated Recognition Distances at Night

Inadequate pedestrian detection is a crucial contributing factor in fatal nighttime collisions involving pedestrians. Pedestrians typically overestimate how recognizable they are to oncoming drivers and little is known about what affects pedestrians\u27 estimates of how recognizable they think they are. This study explored the extent to which pedestrians believed their conspicuity was affected by headlight intensity and clothing reflectance. Participants in four clothing conditions and in four different levels of headlight intensity walked to and from a parked vehicle until they felt recognizable to the driver. Estimated recognition distances did not change with variations in headlight intensity, suggesting that pedestrians do not use headlight illumination when judging their own conspicuity. Participants estimated shorter recognition distances when in Black clothing compared to more reflective clothing. These findings indicate a need to educate pedestrians about night visibility issues

Using Personal Environmental Comfort Systems to Mitigate the Impact of Occupancy Prediction Errors on HVAC Performance

Heating, Ventilation and Air Conditioning (HVAC) consumes a significant fraction of energy in commercial buildings. Hence, the use of optimization techniques to reduce HVAC energy consumption has been widely studied. Model predictive control (MPC) is one state of the art optimization technique for HVAC control which converts the control problem to a sequence of optimization problems, each over a finite time horizon. In a typical MPC, future system state is estimated from a model using predictions of model inputs, such as building occupancy and outside air temperature. Consequently, as prediction accuracy deteriorates, MPC performance--in terms of occupant comfort and building energy use--degrades. In this work, we use a custom-built building thermal simulator to systematically investigate the impact of occupancy prediction errors on occupant comfort and energy consumption. Our analysis shows that in our test building, as occupancy prediction error increases from 5\% to 20\% the performance of an MPC-based HVAC controller becomes worse than that of even a simple static schedule. However, when combined with a personal environmental control (PEC) system, HVAC controllers are considerably more robust to prediction errors. Thus, we quantify the effectiveness of PECs in mitigating the impact of forecast errors on MPC control for HVAC systems.Comment: 21 pages, 13 figure

Strengthening Social Networks of Youth Aging Out of Foster Care: Promoting Positive Adult Outcomes

During the transition to adulthood, youth often rely on the people in their life for support. However, for transition-aged foster youth, these supports may not be available or may look different than supports available to youth in the general population. Relationships with supportive adults have been found to help former foster youth transition to adulthood, but little is known about the adults youth have in their network. Foster youth who report increased levels of social capital have been shown to experience higher levels of success in young adulthood. However, as former foster youth transition to adulthood, a lack of in-depth understanding of supportive adults and social networks creates difficulties identifying—and addressing—potential gaps in their social network. This study aims to gain a better understanding of how social networks influence social support and access to and mobilization of social capital as youth leave the foster care system. A social network assessment based on two existing measures was created to attain a better understanding of the social networks of transition-aged foster youth. The new social network tool was piloted with a group of young adults prior to use in this study. This social network tool allowed for an in-depth understanding of social networks, social support, and social capital as three distinct constructs. The social network characteristics included: on whom the youth relies for support, how the relationship developed, and the closeness of the relationship. Social support included: questions on the type of support available to youth (resources, emotional, advice, or constructive criticism), as well as the social support domains (housing, education, employment, relationships, and transportation). Social capital was examined based on questions about network members’ occupation(s) and frequency of communication between the youth and each network member. Univariate, Bivariate, and Multivariate analyses were utilized to examine social network characteristics, foster care history, social support, and social capital. The mean network size of sample participants was 7.1 and the range was 0–36. A relationship between placement type and social network members was found; indicating that youth in congregate care were more likely to have formal (social service related) networks than youth not in congregate care. A relationship between having more informal network members and housing stability was found; indicating that different network members may help youth with different young adult outcomes. A relationship between both access to, and mobilization of, social capital was found based on the type of social network members (formal, informal, familial-biological, familial-foster). Based on the findings of the current study, research and practice implications are discussed. These include the utility of social network analysis with transition-aged foster youth, future lines of inquiry, and suggested practice/policy shifts

Antibiotic-resistant bacteria in wastewater and potential human exposure through wastewater reuse

As community-acquired antibiotic-resistant bacterial infections occur with increasing frequency, it is important to identify possible environmental reservoirs for these organisms. My dissertation evaluated the presence of antibiotic-resistant bacteria in U.S. wastewater intended for reuse and the related public health implications. My objectives were to: 1) Evaluate wastewater from four U.S. wastewater treatment plants (WWTPs) for the presence of methicillin-resistant Staphylococcus aureus (MRSA); 2) Evaluate the occurrence of vancomycin-resistant enterococci (VRE) at four U.S. WWTPs from which treated wastewater is reused; and 3) Determine and compare MRSA, methicillin-susceptible S. aureus (MSSA), VRE, and vancomcyin-susceptible enterococci (VSE) colonization among American reclaimed water spray irrigators and controls. Between 2009 and 2010, 44 wastewater samples were collected from four WWTPs, two in the Mid-Atlantic and two in the Midwest regions of the U.S. I analyzed samples for MRSA and VRE using standard membrane filtration. For the third objective, I collected 94 nasal and dermal swabs from 19 spray irrigators and 24 controls and analyzed them for MRSA, MSSA, VRE, and VSE. I confirmed all isolates and performed antimicrobial susceptibility testing by microbroth dilution. Statistical analyses included two-sample proportion tests and logistic regression. MRSA and VRE were detected at all WWTPs. The percentage of MRSA-positive samples and concentration of VRE decreased as treatment progressed. Neither MRSA nor VRE were identified in tertiary-treated samples, but I identified both in an un-chlorinated effluent sample. No MRSA or VRE were detected in nasal or dermal samples from spray irrigators or controls. MSSA and VSE were detected in 26% and 11% of spray irrigators and 29% and 0% of controls, respectively. The odds of MSSA, MDR MSSA, and either MSSA or VSE colonization were not significantly different between the spray irrigators and controls. My dissertation includes the first reports of MRSA at U.S. WWTPs and VRE at WWTPs whose effluent is intended for reuse. This is also the first U.S. evaluation of occupational exposure to antibiotic-resistant bacteria in reclaimed water. My findings provide additional scientific evidence that antibiotic-resistant bacteria can survive secondary-treated wastewater and may cause increased risks for infection among individuals exposed to reclaimed water

Improving Delivery of Evidence-Based Prenatal Care in a Family Medicine Clinic

Background: According to the Institute of Medicine, using evidence-based decision-making is one of the key principles that will enable the health care system to provide consistent, high-quality medical care to all people. This can be a challenge when providing care to pregnant women, as ethical issues regarding research in this population have resulted in a relative dearth of high quality randomized control trials providing evidence for prenatal issues. The challenge of providing evidence-based prenatal care is further compounded in a busy Family Medicine teaching practice where pregnant women represent a relatively small fraction of the patients seen on a daily basis. Purpose: The purpose of this project was to develop concise, evidence-based protocols for the management of several common prenatal problems and implement them in a Family Medicine clinic in order to improve the quality of care provided to pregnant women in this practice. Methods: First, four common prenatal problems were identified: 1) Obesity in Pregnancy; 2) Prior Preterm Labor; 3) Gestational Diabetes; and 4) Chronic Hypertension in Pregnancy. For each of these problems, a comprehensive review of the literature was performed. Priority was given to guidelines from professional organizations, meta-analyses and randomized control trials. Using the strongest evidence from all of these sources, a one-page protocol was developed for each condition. The protocols then underwent a review process by the physicians at the clinic. In areas where no strong evidence existed, medico-legal considerations and consensus-derived provider preferences were incorporated into the protocols. Results: In each of the four problems of interest, there existed at least one recommendation that had strong evidence to support it. These recommendations included screening tools, counseling topics and pharmacologic interventions. Conclusions: The first phase of this project has resulted in the development of concise, evidence-based protocols for care of patients with four common prenatal problems that can now be instituted in the Family Medicine clinic. These protocols incorporate the strongest evidence available, and on issues where no strong evidence is available, they take into consideration medico-legal issues and provider preferences derived from a consensus process. We hope that the availability of these protocols will result in more consistent, evidence-based prenatal care. The next steps will be to assess provider utilization of and satisfaction with the protocols, as well as gather outcomes data to see if the implementation of these protocols results in better patient outcomes

EVALUATION OF ANTIBIOTIC-RESISTANT BACTERIA IN TERTIARY TREATED WASTEWATER, RECLAIMED WASTEWATER USED FOR SPRAY IRRIGATION, AND RESULTING OCCUPATIONAL EXPOSURES

Occupational exposures to vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) in reclaimed wastewater used for spray irrigation were evaluated. In 2009, wastewater was collected from a tertiary-treatment facility, and reclaimed wastewater, nasal and dermal swab samples from an irrigation site. Samples were evaluated for MRSA and VRE using standard methods, PCR, and susceptibility testing. MRSA and VRE were isolated from all wastewater samples except effluent. While wastewater MRSA isolates were multidrug resistant (98%), no MRSA was isolated in irrigation water or swabs. VRE was isolated in one irrigation water sample. Fewer irrigation workers were colonized with S. aureus (31%) compared to controls (46%), but they harbored more multidrug resistant S. aureus. This is the first study to 1) evaluate antibiotic-resistant bacteria (ARB) in U.S. reclaimed wastewater and resulting occupational exposures, and 2) detect MRSA in U.S. wastewater. The findings suggested that tertiary wastewater treatment effectively reduced MRSA and VRE