861 research outputs found
Systemic highway safety assessment: A general analysis of funding allocation and a specific study of the horizontal curve crash problem
It is well documented that motor vehicle crashes are a public safety concern. However, traditional approaches do not always lend themselves to addressing the complete extent of this safety problem . Identifying the extent of the safety problem is an important step in optimizing safety fund allocation and analyzing horizontal curve safety. This study investigates the allocation of safety expenditures in Iowa, relative to crash data. The matching of crash data with safety expenditures suggests the shift of funds from the high crash density, state system to facilities on the low density, local system. However, the redistribution of funding should also consider factors such as crash density and benefit cost. Furthermore, because some crashes are too widely distributed to be identified using traditional high crash location methodology; a balance of systematic and high crash location methods should be considered. Ultimately, the optimum balance of safety resources should reduce the most possible fatal and serious injury crashes. This study also investigated a systematic method for identifying and estimating geometric parameters on horizontal curves. A validation of this method showed that as horizontal curve radius decrease, sensitivity to errors in the estimated curve radius increase. Although some large errors associated with the estimated curve radius were found, predicted crash frequency for all curves was found to be no more than twenty percent different than the actual predicted crash frequency. Lastly, safety performance functions created for the horizontal curve database did not yield a concrete correlation between curve radius and crash frequency. Because of the random nature of fatal and major injury crashes, care is advised when creating crash models for these crashes
Applications of vortex gas models to tornadogenesis and maintenance
Processes related to the production of vorticity in the forward and rear
flank downdrafts and their interaction with the boundary layer are thought to
play a role in tornadogenesis. We argue that an inverse energy cascade is a
plausible mechanism for tornadogenesis and tornado maintenance and provide
supporting evidence which is both numerical and observational. We apply a
three-dimensional vortex gas model to supercritical vortices produced at the
surface boundary layer possibly due to interactions of vortices brought to the
surface by the rear flank downdraft and also to those related to the forward
flank downdraft. Two-dimensional and three-dimensional vortex gas models are
discussed, and the three-dimensional vortex gas model of Chorin, developed
further by Flandoli and Gubinelli, is proposed as a model for intense small-
scale subvortices found in tornadoes and in recent numerical studies by Orf et
al. In this paper, the smaller scales are represented by intense, supercritical
vortices, which transfer energy to the larger-scale tornadic flows (inverse
energy cascade). We address the formation of these vortices as a result of the
interaction of the flow with the surface and a boundary layer.Comment: 20 pages, 6 figure
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Uric Acid as a Potential Peripheral Biomarker for Disease Features in Huntington's Patients.
Oxidative stress has long been implicated in the pathophysiology and progression of Huntington's disease (HD). Uric acid (UA) is a naturally occurring antioxidant that is present in the brain and periphery. Growing evidence has implicated UA as a molecular biomarker for several neurodegenerative diseases, most notably Parkinson's disease (PD). In this study, we investigated UA levels in clinical samples from HD patients and normal controls (NCs) and assessed potential relationships between UA levels and disease and clinical data. UA levels were measured in plasma (n = 107) and saliva (n = 178) samples from premanifest (pre-HD) and manifest HD patients and control subjects. Gender effects of UA levels were observed in both biofluids, with male patients showing higher UA levels compared to female patients. Comparisons of UA levels across diagnostic groups, separated by gender, revealed that both plasma and salivary UA levels were significantly lower in female pre-HD and manifest HD patients compared to NCs. Salivary levels of UA were also significantly lower in male manifest HD patients versus controls, but not in plasma. Correlations of peripheral UA levels to clinical data also showed differences according to gender. In male HD patients, both plasma and salivary UA levels were significantly negatively correlated with total functional capacity (TFC), while positive correlations were observed with total motor score (TMS). Female HD patients showed a significant positive correlation between plasma UA levels and TMS, while salivary UA levels from female patients were significantly correlated to disease burden. Finally, in a separate cohort, we show that UA levels are decreased in postmortem prefrontal cortical samples (n = 20) from HD subjects compared to matched controls. These findings suggest that decreased levels of UA in the brains of HD patients can be reflected in peripheral fluids, with salivary measures of UA particularly offering significant promise as a potentially relevant, non-invasive biomarker of disease symptoms and burden. Our findings further highlight the impact of sexual dimorphism in HD pathophysiology
Energy materiality : a conceptual review of multi-disciplinary approaches
This jointly authored essay reviews recent scholarship in the social sciences, broadly understood, that focuses on the materiality of energy. Although this work is extraordinarily diverse in its disciplinary and interdisciplinary influences and its theoretical and methodological commitments, we discern four areas of convergence and divergence that we term the locations, uses, relationalities, and analytical roles of energy materiality. We trace these convergences and divergences through five recent scholarly conversations: materiality as a constraint on actors’ behavior; historical energy systems; mobility, space and scale; discourse and power via energy materialities; and energy becoming material.Peer reviewe
Applications of a vortex gas models to tornadogenesis and maintenance
Processes related to the production of vorticity in the forward and rear flank downdrafts and their interaction with the boundary layer are thought to play a role in tornadogenesis. We argue that an inverse energy cascade is a plausible mechanism for tornadogenesis and tornado maintenance and provides supporting evidence which is both numerical and observational. We apply a three-dimensional vortex gas model to supercritical vortices produced at the surface boundary layer possibly due to interactions of vortices brought to the surface by the rear flank downdraft and also to those related to the forward flank downdraft. Two-dimensional and three-dimensional vortex gas models are discussed, and the three-dimensional vortex gas model of Chorin, developed further by Flandoli and Gubinelli, is proposed as a model for intense small-scale subvortices found in tornadoes and in recent numerical studies by Orf et al. In this paper, the smaller scales are represented by intense, supercritical vortices, which transfer energy to the larger-scale tornadic flows (inverse energy cascade). We address the formation of these vortices as a result of the interaction of the flow with the surface and a boundary layer
Engineering, nutrient removal, and feedstock conversion evaluations of four corn stover harvest scenarios
Crop residue has been identified as a near-term source of biomass for renewable fuel, heat, power, chemicals and other bio-materials. A prototype one-pass harvest system was used to collect residue samples from a corn (Zea mays L.) field near Ames, IA. Four harvest scenarios (low cut, high-cut top, high-cut bottom, and normal cut) were evaluated and are expressed as collected stover harvest indices (CSHI). High-cut top and high-cut bottom samples were obtained from the same plot in separate operations. Chemical composition, dilute acid pretreatment response, ethanol conversion yield and efficiency, and thermochemical conversion for each scenario were determined. Mean grain yield in this study (10.1 Mg ha−1 dry weight) was representative of the average yield (10.0 Mg ha−1) for the area (Story County, IA) and year (2005). The four harvest scenarios removed 6.7, 4.9, 1.7, and 5.1 Mg ha−1 of dry matter, respectively, or 0.60 for low cut, 0.66 for normal cut, and 0.61 for the total high-cut (top+bottom) scenarios when expressed as CSHI values. The macro-nutrient replacement value for the normal harvest scenario was 11.27 Mg−1. Harvesting stalk bottoms increased stover water content, risk of combine damage, estimated transportation costs, and left insufficient soil cover, while also producing a problematic feedstock. These preliminary results indicate harvesting stover (including the cobs) at a height of approximately 40 cm would be best for farmers and ethanol producers because of faster harvest speed and higher quality ethanol feedstock
Technical Report: Distributed Parallel Computing Using Windows Desktop Systems
See also: http://sbml.org/Main_PageLike many large institutions, Indiana University has thousands of desktop computers devoted primarily to running office productivity applications on the Windows operating system, tasks which are necessary but that do not use the computers’ full capacity. This is a resource worth pursuing. However, the individual desktop systems do not offer enough processing power for a long enough period of time to complete large scientific computing applications. Some form of distributed, parallel programming is required, to make them worth the chase. They must be instantly available to their primary users, so they are available only intermittently. This has been a serious stumbling block: currently available communications libraries for distributed computing do not support such a dynamic communications world well. This paper introduces Simple Message Broker Library (SMBL), which provides the flexibility needed to take advantage of such ephemeral resources
Assessing the Risk of SARS-CoV-2 Transmission via Surgical Electrocautery Plume
This quality improvement study used a nonhuman subject research approach to examine whether SARS-CoV-2 from aerosolized virus is present in and potentially transmissible from a electrocautery plume in surgery
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