907 research outputs found
Evaluation of red-light camera enforcement using traffic violations
The State of Qatar started to use red-light cameras in 2007 at key signalized intersections and the rate of installation has subsequently increased. In 2017, 19.2% of signalized intersections are equipped with red-light cameras. In many cases, the cameras are not installed on all approaches to the intersections. The purpose of this study is to compare the red-light running violations on approaches with and without red-light running enforcement cameras at the same intersections. Actual field observations were used in this study. Different variables were investigated, including the day of the week, time of day, traffic volume, the possibility of glare on an approach, and the lengths of the yellow and all-red times. A regression tree model was used to explain the characteristics associated with the violations. The results showed that the number of violations on low-volume approaches was five times higher than on high-volume approaches. The results also showed that the presence of the cameras significantly lowered red-light running violations. High-volume approaches without cameras had an approximately eight times higher rate of violations than high-volume approaches with cameras. The analysis also showed that bringing the all-red interval closer to the values recommended by the Institute of Transportation Engineers formula may bring down the rates of violations for low-volume approaches. As with any observational data mining method, the study could benefit from a larger sample size. The method used in the study was effective and is easily transferable to other locations. The results of this study can be used in developing new strategies to improve safety at signalized intersections. 2018 The AuthorsScopu
A simple method to assess walkability around metro stations
The ability to walk or ride a bike safely to and from metro stations is essential to the success of any metro service, especially for car users switching to the service. The main purpose of this study is to develop and apply a simple method to assess, compare, and rank walkability around different metro stations, with a priority order and specific recommendations for improvements. The proposed method depends on extracting different walkability variables in the catchment areas around metro stations. Three catchment areas around three proposed metro stations in the emerging city of Doha, Qatar were investigated using the proposed method to demonstrate its usefulness. The method was successful in comparing and ranking the different catchment areas, in addition to identifying priority areas for walkability enhancements in each area. This method is simple and can benefit professionals, practitioners, and policy makers to make swift decisions for future corrective measures, and can also be used to evaluate changes over time. 2018 Inderscience Enterprises Ltd.Scopu
Real-time ultrasound elastography: Does it improve B-mode ultrasound characterization of solid breast lesions?
AbstractIntroductionElastography is a non-invasive medical imaging technique that detects tumors based on their stiffness (elasticity). Strain images display the relative stiffness of lesions compared with the stiffness of surrounding tissue as cancerous tumors tend to be many times stiffer than the normal tissue, which “gives” under compression. An image in which different degrees of stiffness show as different shades of light and dark is called an elastogram.PurposeTo prospectively evaluate the sensitivity and specificity of the real-time sonoelastography as compared with B-mode US for distinguishing between benign and malignant solid breast masses. The density of the glandular breast tissue was taken in consideration in addition to the Breast Imaging Reporting and Data System (BI-RADS) categories of the lesions, with biopsy results as the reference standard.MethodsA total of 216 candidate solid lesions (123 benign and 93 malignant) in 188 patients were examined with 2-dimensional ultrasonography, elastosonography and mammography (for 147 patients). The lesions were classified according to the density of the glandular breast tissue into low density group (D1) and a high density group (D2) and were categorized with the BIRADS score. Elastographic images were assigned an elasticity score of 1 to 5 (1–3, benign; 4 and 5, malignant) according to the Multi-Center Team of Study and the strain ratios of the lesions were measured. Concordance between the imaging findings and histopathologic results was documented. Statistical analysis was performed and sensitivity, specificity and positive and negative predictive values for both elastography and conventional sonography were calculated.ResultsElastography showed less sensitivity but higher specificity than conventional sonography in the differentiation of benign from malignant solid lesions: B-mode sonography had sensitivity of 85.1%, specificity of 93.9%, a positive predictive value of 92.5% and a negative predictive value of 87.8%, compared with the sensitivity of 80.1%, specificity of 97.1%, a positive predictive value of 96.8% and a negative predictive value of 82.1% for elastography. Elastography was superior to B-mode US in diagnosing solid lesions in the low density group (D1) (96.6% vs. 92.4% specificity) and less in the dense glandular tissue (97.8% vs. 95.9% specificity).ConclusionsReal-time sonoelastography is an useful technique for the characterization of benign and malignant solid lesions as it increases the diagnostic specificity comparable to B-mode ultrasound, particularly in both ACR 1 and 2, thus reducing the false-positive rate
14-Bromo-12-chloro-2,16-dioxapentacyclohenicosa-3(8),10,12,14-tetraene-7,20-dione
In the title compound, C19H16BrClO4, both the fused xanthene rings and one of the cyclohexane rings adopt envelope conformations, while the other cyclohexane ring is in a chair conformation. In the crystal, molecules are linked by C-H...O hydrogen bonds, forming infinite chains running along [10-1] incorporating R22(16) ring motifs. In addition, C-H...[pi] interactions and weak [pi]-[pi] stacking interactions [centroid-centroid distance = 3.768 (3) Å] help to consolidate the packing
2,2′-[(E,E)-cis-(Cyclohexane-1,4-diyl)bis(nitrilomethanylylidene)]diphenol
In the title compound, C20H22N2O2, the asymmetric unit contains two independent half-molecules, which are both completed by crystallographic inversion symmetry. The cyclohexane rings of both molecules adopt chair conformations; the N atoms are in equatorial orientations in one molecule and in axial orientations in the other. Both molecules feature two intramolecular O—H⋯N hydrogen bonds, which generate S(6) rings
2-((E)-{[4-(Hydroxymethyl)phenyl]imino}methyl)phenol
The title compound, C14H13NO2, adopts the enol–imine tautomeric form, with an intramolecular O—H⋯N hydrogen bond which generates an S(6) ring motif. The dihedral angle between the aromatic rings is 7.85 (7)°. The crystal structure is stabilized by O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, forming a two-dimensional array that stacks along the a axis. In addition, a C—H⋯π interaction contributes to the stabilization of the crystal packing
Crystal structure of ethyl 2-[2-((1E)-{(1E)-2-[2-(2-ethoxy-2-oxoethoxy)benzyl-idene]hydrazin-1-ylidene}methyl)phen-oxy]acetate
NSF–MRI grant No. 1228232 for the purchase of the diffractometer and Tulane University for support of the Tulane Crystallography Laboratory are gratefully acknowledged.Peer reviewedPublisher PD
(6Z)-4-Bromo-6-{[(2-hydroxyethyl)amino]methylidene}cyclohexa-2,4-dien-1-one
The title molecule, C9H10BrNO2, excluding methylene H atoms and the C—OH group, is essentially planar, with a maximum deviation of 0.037 (2) Å for the N atom. The N—C—C—O torsion angle is −63.1 (3)°. The molecular structure is stabilized by a weak intramolecular N—H⋯O(carbonyl) hydrogen bond, forming an S(6) motif. In the crystal, molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network
7-Bromo-9-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one
In the xanthene ring system of the title compound, C23H25BrO4, the 4H-pyran ring is almost planar [maximum deviation = 0.040 (3) Å] and the cyclohexene ring adopts a sofa conformation. The cyclohexene ring attached to the xanthene system is puckered [Q
T = 0.427 (3) Å, θ = 55.0 (4) ° and ϕ = 164.4 (6) °]. In the crystal, molecules are linked to each other by O—H⋯O and C—H⋯O hydrogen bonds
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