850 research outputs found
Distance Perception with a Camera-Based Rear Vision System in Actual Driving
Participants drove an instrumented car equipped with conventionalrearview mirrors and with a camera rear vision system. They observed theapproach of an overtaking car in the alternative rear vision systems and indicatedthe last moment at which it would be safe to initiate a lane-change maneuver infront of it. Their judgments were strongly affected by the type of display used toobserve the overtaking car. The longest distances were obtained with the camerabaseddisplay at unit magnification. Distances were substantially shorter with theconventional mirror and with the camera-based display at 0.5 minification. Theseresults are consistent with results from an earlier study conducted under staticconditions
Factors affecting color correction of retroreflective markings
A nighttime field study was conducted to assess the effects of retroreflective material area, distribution, and
color on judgments of conspicuity. Participants, seated in a stationary vehicle, took part in a pairwise comparison
of the stimuli. The independent variables included retroreflective power, area and distribution of the
retroreflective material, color of the retroreflective material, participant age, and participant gender.
The results indicate that color (white, fluorescent yellow-green, and fluorescent red-orange) was a significant
factor in the judgment of conspicuity, as might be predicted from the Helmholtz-Kohlrausch effect. In addition,
color interacted with the distribution of material at the high level of retroreflective power. The area of the
retroreflective material was also significant.
The present study, in agreement with a number of previous studies, indicates that color influences the
conspicuity of retroreflective stimuli, but that the results are not always in agreement with color correction factors
prescribed in ASTM E 1501. The discrepancy between empirically derived color correction factors seems to be
attributable to an interaction of the stimulus size (subtended angle) and color, which previous studies have not
extensively examined. To a lesser degree, the retroreflective power of a material also appears to influence
conspicuity.
While the ASTM correction factors may be appropriate for intermediate subtended solid angles, particularly for
nonsaturated colors, smaller correction factors appear appropriate for markings subtending small angles
(approaching point sources), and larger factors for larger subtended angles of saturated stimuli.The University of Michigan Industry Affiliation Program for Human Factors in Transportation Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/91263/1/102869.pd
A Simple and Effective Display for Night Vision Systems
The next generation of automotive night vision systems will likely continue to display to the driver enhanced images of the forward driving scene. In some displays there may also be highlighting of pedestrians and animals, which has been argued to be the primary safety goal of night vision systems. We present here the method that was used to design a conceptual display for night vision systems. Although the primary focus of the method is on safety analysis, consideration is given to driver performance with the system, and exposure to alerts. It also addresses user acceptance and annoyance, distraction, and expected behavior adaptation. The resulting driver interface is a simple and potentially effective display for night vision systems. It consists of a pedestrian icon that indicates when there are pedestrians near the future path of the vehicle. An initial prototype of this night-vision DVI was tested on the road and showed promising results despite its simplicity. It improved pedestrian detection distance from 34 to 44 m and decreased the overall ratio of missed pedestrians from 13% to 5%, correspondingly. The improvement may be attributable to the icon alerting the driver to the presence of a pedestrian. In this experiment, the drivers were probably more alert to the possible presence of pedestrians than drivers in the real world, suggesting that the effect of the icon might be even larger in actual use
Charge Symmetry Breaking in 500 MeV Nucleon-Trinucleon Scattering
Elastic nucleon scattering from the 3He and 3H mirror nuclei is examined as a
test of charge symmetry violation. The differential cross-sections are
calculated at 500 MeV using a microsopic, momentum-space optical potential
including the full coupling of two spin 1/2 particles and an exact treatment of
the Coulomb force. The charge-symmetry-breaking effects investigated arise from
a violation within the nuclear structure, from the p-nucleus Coulomb force, and
from the mass-differences of the charge symmetric states. Measurements likely
to reveal reliable information are noted.Comment: 5 page
Field Test Results of a Road Departure Crash Warning System: Driver Acceptance, Perceived Utility and Willingness to Purchase
The road departure crash warning system field operational test (RDCW FOT) was conducted to assess the safety impacts, driver acceptance levels, and the maturity of road departure crash warning systems as installed on a light vehicle platform. This paper presents the results on driver acceptance and perceived utility of a road departure crash warning system
Becoming an older volunteer: A grounded theory study.
This Grounded Theory study describes the process by which older persons âbecomeâ volunteers. Forty interviews of older persons who volunteered for Habitat for Humanity were subjected to secondary content analysis to uncover the process of âbecomingâ a volunteer. âHelping outâ (core category) for older volunteers occurs within the context of âcontinuityâ, âcommitmentâ and âconnectionâ which providemotivation for volunteering.When a need arises, older volunteers âhelp outâ physically and financially as health and resources permit. Benefits described as âblessingsâ of volunteering become motivators for future volunteering. Findings suggest that older volunteering is a developmental process and learned behavior which should be fostered in older persons by personally inviting them to volunteer. Intergenerational volunteering projects will allow older persons to pass on knowledgeand skills and provide positive role modeling for younger volunteers
Water electrolysis on La1âxSrxCoO3âÎŽ perovskite electrocatalysts
Perovskite oxides are attractive candidates as catalysts for the electrolysis of water in alkaline energy storage and conversion systems. However, the rational design of active catalysts has been hampered by the lack of understanding of the mechanism of water electrolysis on perovskite surfaces. Key parameters that have been overlooked include the role of oxygen vacancies, BâO bond covalency, and redox activity of lattice oxygen species. Here we present a series of cobaltite perovskites where the covalency of the CoâO bond and the concentration of oxygen vacancies are controlled through Sr[superscript 2+] substitution into La[scubscript 1âx]Sr[scubscript x]CoO[scubscript 3âÎŽ]. We attempt to rationalize the high activities of La[scubscript 1âx]Sr[scubscript x]CoO[scubscript 3âÎŽ] through the electronic structure and participation of lattice oxygen in the mechanism of water electrolysis as revealed through ab initio modelling. Using this approach, we report a material, SrCoO[subscript 2.7], with a high, room temperature-specific activity and mass activity towards alkaline water electrolysis.Robert A. Welch Foundation (grant F-1529)Robert A. Welch Foundation (grant F-1319)MIT Skoltech Initiative (Massachusetts Institute of Technology. Center for Electrochemical Energy Storage
Pharmacotherapy in Coronavirus Disease 2019 and Risk of Secondary Infections: A Single-Center Case Series and Narrative Review
OBJECTIVES: Since the onset of the coronavirus disease 2019 pandemic, immune modulators have been considered front-line candidates for the management of patients presenting with clinical symptoms secondary to severe acute respiratory syndrome coronavirus 2 infection. Although heavy emphasis has been placed on early clinical efficacy, we sought to evaluate the impact of pharmacologic approach to coronavirus disease 2019 within the ICU on secondary infections and clinical outcomes.
DATA SOURCES: PubMed (inception to March 2021) database search and manual selection of bibliographies from selected articles.
STUDY SELECTION AND DATA EXTRACTION: Articles relevant to coronavirus disease 2019, management of severe acute respiratory syndrome coronavirus 2-associated respiratory failure, and prevalence of secondary infections with pharmacotherapies were selected. The MeSH terms COVID-19, secondary infection, SARS-CoV-2, tocilizumab, and corticosteroids were used for article identification. Articles were narratively synthesized for this review.
DATA SYNTHESIS: Current data surrounding the use of tocilizumab and/or corticosteroids for coronavirus disease 2019 management are limited given the short follow-up period and conflicting results between studies. Further complicating the understanding of immune modulator role is the lack of definitive understanding of clinical impact of the immune response in coronavirus disease 2019.
CONCLUSIONS: Based on the current available literature, we suggest prolonged trials and follow-up intervals for those patients managed with immune modulating agents for the management of coronavirus disease 2019
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Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996
The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil and gas producing regions of Wyoming, are well suited for application of these processes in combination. Specifically, the objectives of this research are related to the development of a commercially-economic FTE (freeze-thaw/evaporation) process for the treatment and purification of water produced in conjunction with oil and natural gas. The research required for development of this process consists of three tasks: (1) a literature survey and process modeling and economic analysis; (2) laboratory-scale process evaluation; and (3) field demonstration of the process. Results of research conducted for the completion of these three tasks indicate that produced water treatment and disposal costs for commercial application of the process, would be in the range of 0.30/bbl in the Rocky Mountain region. FTE field demonstration results from northwestern New Mexico during the winter of 1995--96 indicate significant and simultaneous removal of salts, metals, and organics from produced water. Despite the unusually warm winter, process yields demonstrate disposal volume reductions on the order of 80% and confirm the potential for economic production of water suitable for various beneficial uses. The total dissolved solids concentrations of the FTE demonstration streams were 11,600 mg/L (feed), 56,900 mg/L (brine), and 940 mg/L (ice melt)
Phenotypic Spectrum of Seizure Disorders in MBD5-Associated Neurodevelopmental Disorder
OBJECTIVE: To describe the phenotypic spectrum in patients with MBD5-associated neurodevelopmental disorder (MAND) and seizures; features of MAND include intellectual disability, epilepsy, psychiatric features of aggression and hyperactivity, and dysmorphic features including short stature and microcephaly, sleep disturbance, and ataxia. METHODS: We performed phenotyping on patients with MBD5 deletions, duplications, or point mutations and a history of seizures. RESULTS: Twenty-three patients with MAND and seizures were included. Median seizure onset age was 2.9 years (range 3 daysâ13 years). The most common seizure type was generalized tonic-clonic; focal, atypical absence, tonic, drop attacks, and myoclonic seizures occurred frequently. Seven children had convulsive status epilepticus and 3 nonconvulsive status epilepticus. Fever, viral illnesses, and hot weather provoked seizures. EEG studies in 17/21 patients were abnormal, typically showing slow generalized spike-wave and background slowing. Nine had drug-resistant epilepsy, although 3 eventually became seizure-free. All but one had moderate-to-severe developmental impairment. Epilepsy syndromes included Lennox-Gastaut syndrome, myoclonic-atonic epilepsy, and infantile spasms syndrome. Behavioral problems in 20/23 included aggression, self-injurious behavior, and sleep disturbance. CONCLUSION: MBD5 disruption may be associated with severe early childhood-onset developmental and epileptic encephalopathy. Because neuropsychiatric dysfunction is common and severe, it should be an important focus of clinical management
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