Financing rural homes in Missouri

Missouri Agricultural Experiment Station and the Farm Production Economics Division, Economic Research Service, U.S. Department of Agriculture, cooperating.Digitized 2007 AES.Includes bibliographical references (page 43)

Impacts of Mixed Use and Density on Utilization of Three Modes of Travel: Single-Occupant Vehicle, Transit, and Walking,"

Findings from an empirical analysis to test the impacts of land-use mix, population density, and employment density on the use of the singleoccupant vehicle (SOV), transit, and walking for both work trips and shopping trips are presented. The hypothetical relationships tested focused on whether there is a relationship between urban form and modal choice, whether this relationship exists when controlling for non-urban form factors, whether this relationship is linear or nonlinear, and whether a stronger relationship exists between modal choice and urban form when they are measured at both trip ends as opposed to either the origin or the destination. A review of the literature and experiences suggested that a fair amount of information is known about the impacts of density on mode choice. However, considerable debate exists over whether density itself is actually the causal stimulus or a surrogate for other factors. To address this issue a data base was developed with a comprehensive set of variables for which density may be a proxy, for example, demographics and level of service. This analysis employed a correlational research design in which mode choice was compared among census tracts with differing levels of density and mix. Findings from this research indicate that density and mix are both related to mode choice, even when controlling for non-urban form factors for both work trips and shopping trips. Furthermore, the relationship between population and employment density and mode choice for SOV, transit, and walking is nonlinear for both work and shopping trips. Transit usage and walking increase as density and land-use mix increase, whereas SOV usage declines. The findings from this research suggest that measuring urban form at both trip ends provides a greater ability to predict travel choices than looking at trip ends separately. The findings also suggest that increasing the level of land-use mix at the trip origins and destinations is also related to a reduction in SOV travel and an increase in transit and walking. This research is important because of recent policy initiatives at the federal, state, and local levels that state that it is no longer feasible to maintain access to opportunities in urban areas by increasing the mobility of SOVs. Among the commonly cited reasons are economics, new environmental legislation (e.g., the Clean Air Act Amendments of 1990), public opposition, changing demographics, and political pressure to reduce fuel consumption. Several urbanform strategies have been recommended to reduce dependence on driving alone. These strategies include increasing residential and employment densities and intermixing a variety of land uses (residential, employment, and commercial). Although these strategies would seem to enhance the viabilities of alternatives to SOVs, relatively little work has been conducted to test these relationships empirically. STRUCTURE OF ANALYSIS The findings presented in this paper are based on a three-phase research approach. In Phase I information was gathered from other sources resulting in the identification of hypothetical relationships between urban form and travel behavior on the basis of theory, past research findings, and current policies. In Phase II the project data base was developed to test these hypothetical relationships. Statistical techniques were used to conduct hypothesis testing (e.g., multiple regression or correlation) in Phase III. This project is part of a research agenda developed by the University of Washington for the Washington State Department of Transportation (WSDOT). The goal of the agenda is to discover ways to plan and implement urban forms that promote increased accessibility. At the crux of this agenda are the intentions to decrease the need to travel, reduce dependence on the single-occupant vehicle (SOV), and enhance the competitiveness of other travel modes. More specifically, this paper documents empirical relationships between urban form (land-use mix and density) and trip making by individuals who use SOVs, transit, and walking as modes of travel. This analysis focuses on two trip purposes: working and shopping. POLICY PERSPECTIVE Over the past 3 years several policies that are intended to reduce the rate of growth in travel demand through the manipulation of urbanform and a variety of other factors have been enacted at the federal, state, and local levels. These policies are based on a variety of hypotheses that characterize the nature of the relationship between travel demand and both urban-form and non-urban-form factors. Although the intent of this research was to provide insight regarding urban form, it also tested and evaluated the relative impacts of nonurban-form factors. Selected policies that target both urban-form and non-urban-form factors and that affect travel demand include • The Intermodal Surface Transportation Efficiency Act of 1991, which provides new funding opportunities for non-SOV improvements

Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12)

It has been known for the past 20 years that two pathways exist in nature for the de novo biosynthesis of the coenzyme form of vitamin B12, adenosylcobalamin, representing aerobic and anaerobic routes. In contrast to the aerobic pathway, the anaerobic route has remained enigmatic because many of its intermediates have proven technically challenging to isolate, because of their inherent instability. However, by studying the anaerobic cobalamin biosynthetic pathway in Bacillus megaterium and using homologously overproduced enzymes, it has been possible to isolate all of the intermediates between uroporphyrinogen III and cobyrinic acid. Consequently, it has been possible to detail the activities of purified cobinamide biosynthesis (Cbi) proteins CbiF, CbiG, CbiD, CbiJ, CbiET, and CbiC, as well as show the direct in vitro conversion of 5-aminolevulinic acid into cobyrinic acid using a mixture of 14 purified enzymes. This approach has resulted in the isolation of the long sought intermediates, cobalt-precorrin-6A and -6B and cobalt-precorrin-8. EPR, in particular, has proven an effective technique in following these transformations with the cobalt(II) paramagnetic electron in the dyz orbital, rather than the typical dz2. This result has allowed us to speculate that the metal ion plays an unexpected role in assisting the interconversion of pathway intermediates. By determining a function for all of the pathway enzymes, we complete the tool set for cobalamin biosynthesis and pave the way for not only enhancing cobalamin production, but also design of cobalamin derivatives through their combinatorial use and modification

Anatomic Fat Depots and Coronary Plaque Among Human Immunodeficiency Virus-Infected and Uninfected Men in the Multicenter AIDS Cohort Study.

Methods.  In a cross-sectional substudy of the Multicenter AIDS Cohort Study, noncontrast cardiac computed tomography (CT) scanning for coronary artery calcium (CAC) scoring was performed on all men, and, for men with normal renal function, coronary CT angiography (CTA) was performed. Associations between fat depots (visceral adipose tissue [VAT], abdominal subcutaneous adipose tissue [aSAT], and thigh subcutaneous adipose tissue [tSAT]) with coronary plaque presence and extent were assessed with logistic and linear regression adjusted for age, race, cardiovascular disease (CVD) risk factors, body mass index (BMI), and human immunodeficiency virus (HIV) parameters. Results.  Among HIV-infected men (n = 597) but not HIV-uninfected men (n = 343), having greater VAT was positively associated with noncalcified plaque presence (odds ratio [OR] = 1.04, P < .05), with a significant interaction (P < .05) by HIV serostatus. Human immunodeficiency virus-infected men had lower median aSAT and tSAT and greater median VAT among men with BMI <25 and 25-29.9 kg/m(2). Among HIV-infected men, VAT was positively associated with presence of coronary plaque on CTA after adjustment for CVD risk factors (OR = 1.04, P < .05), but not after additional adjustment for BMI. There was an inverse association between aSAT and extent of total plaque among HIV-infected men, but not among HIV-uninfected men. Lower tSAT was associated with greater CAC and total plaque score extent regardless of HIV serostatus. Conclusions.  The presence of greater amounts of VAT and lower SAT may contribute to increased risk for coronary artery disease among HIV-infected persons

Inflammatory Markers Associated With Subclinical Coronary Artery Disease: The Multicenter AIDS Cohort Study.

BackgroundDespite evidence for higher risk of coronary artery disease among HIV+ individuals, the underlying mechanisms are not well understood. We investigated associations of inflammatory markers with subclinical coronary artery disease in 923 participants of the Multicenter AIDS Cohort Study (575 HIV+ and 348 HIV- men) who underwent noncontrast computed tomography scans for coronary artery calcification, the majority (n=692) also undergoing coronary computed tomography angiography.Methods and resultsOutcomes included presence and extent of coronary artery calcification, plus computed tomography angiography analysis of presence, composition, and extent of coronary plaques and severity of coronary stenosis. HIV+ men had significantly higher levels of interleukin-6 (IL-6), intercellular adhesion molecule-1, C-reactive protein, and soluble-tumor necrosis factor-α receptor (sTNFαR) I and II (all P<0.01) and a higher prevalence of noncalcified plaque (63% versus 54%, P=0.02) on computed tomography angiography. Among HIV+ men, for every SD increase in log-interleukin-6 and log intercellular adhesion molecule-1, there was a 30% and 60% increase, respectively, in the prevalence of coronary stenosis ≥50% (all P<0.05). Similarly, sTNFαR I and II in HIV+ participants were associated with an increase in prevalence of coronary stenosis ≥70% (P<0.05). Higher levels of interleukin-6, sTNFαR I, and sTNFαR II were also associated with greater coronary artery calcification score in HIV+ men (P<0.01).ConclusionsHigher inflammatory marker levels are associated with greater prevalence of coronary stenosis in HIV+ men. Our findings underscore the need for further study to elucidate the relationships of inflammatory pathways with coronary artery disease in HIV+ individuals

The TROLLEY Study : Assessing travel, health and equity impacts of a new light rain transit investment during the COVID-19 pandemic

Background The COVID-19 pandemic disrupted life in extraordinary ways impacting health and daily mobility. Public transit provides a strategy to improve individual and population health through increased active travel and reduced vehicle dependency, while ensuring equitable access to jobs, healthcare, education, and mitigating climate change. However, health safety concerns during the COVID-19 pandemic eroded ridership, which could have longstanding negative consequences. Research is needed to understand how mobility and health change as the pandemic recedes and how transit investments impact health and equity outcomes. Methods The TROLLEY (TRansit Opportunities for HeaLth, Livability, Exercise and EquitY) study will prospectively investigate a diverse cohort of university employees after the opening of a new light rail transit (LRT) line and the easing of campus COVID-19 restrictions. Participants are current staff who live either  2 miles from LRT, with equal distribution across economic and racial/ethnic strata. The primary aim is to assess change in physical activity, travel mode, and vehicle miles travelled using accelerometer and GPS devices. Equity outcomes include household transportation and health-related expenditures. Change in health outcomes, including depressive symptoms, stress, quality of life, body mass index and behavior change constructs related to transit use will be assessed via self-report. Pre-pandemic variables will be retrospectively collected. Participants will be measured at 3 times over 2 years of follow up. Longitudinal changes in outcomes will be assessed using multilevel mixed effects models. Analyses will evaluate whether proximity to LRT, sociodemographic, and environmental factors modify change in outcomes over time. Discussion The TROLLEY study will utilize rigorous methods to advance our understanding of health, well-being, and equity-oriented outcomes of new LRT infrastructure through the COVID-19 recovery period, in a sample of demographically diverse adult workers whose employment location is accessed by new transit. Results will inform land use, transportation and health investments, and workplace interventions. Findings have the potential to elevate LRT as a public health priority and provide insight on how to ensure public transit meets the needs of vulnerable users and is more resilient in the face of future health pandemics. Trial registration The TROLLEY study was registered at ClinicalTrials.gov (NCT04940481) June 17, 2021, and OSF Registries (https://doi.org/10.17605/OSF.IO/PGEHU) June 24, 2021, prior to participant enrollment

A noninvasive method for quantifying cerebral blood flow by hybrid PET/MRI

Although PET with 15O-water is the gold standard for imaging cerebral blood flow (CBF), quantification requires measuring the arterial input function (AIF), which is an invasive and noisy procedure. To circumvent this problem, we propose a noninvasive PET/MRI approach that eliminates the need to measure AIF by using global CBF determined by phase-contrast (PC) MRI as a reference region. This approach not only is noninvasive but also involves no additional imaging time, because PC MRI and 15O-water PET are acquired simultaneously. The purpose of this study was to test the accuracy of this hybrid method in an animal model in which AIF was measured directly and CBF was varied by changing the arterial CO2 tension. Methods: PET and MRI data were simultaneously acquired in juvenile pigs at hypocapnia (n 5 5), normocapnia (n 5 5), and hypercapnia (n 5 4). CBF was measured by the MRI reference method and by PET alone using an MRI-compatible blood sampling system to measure AIF. Results: Global CBF estimates from PC MRI and 15O-water PET agreed well, with a correlation coefficient of 0.9 and a slope of 0.88. Strong positive correlations (R2 . 0.96) were also found between regional CBF generated by the PET-only and the MRI-reference methods. Conclusion: These findings demonstrate the accuracy of this hybrid PET/MRI approach, which might prove useful in patients for whom obtaining accurate CBF measurements is challenging