A Recurrent Cooperative/Competitive Field for Segmentation of Magnetic Resonance Brain Imagery

The Grey-White Decision Network is introduced as an application of an on-center, off-surround recurrent cooperative/competitive network for segmentation of magnetic resonance imaging (MRI) brain images. The three layer dynamical system relaxes into a solution where each pixel is labeled as either grey matter, white matter, or "other" matter by considering raw input intensity, edge information, and neighbor interactions. This network is presented as an example of applying a recurrent cooperative/competitive field (RCCF) to a problem with multiple conflicting constraints. Simulations of the network and its phase plane analysis are presented

An investigation into unsteady base bleed for drag reduction in bluff two-box SUVs

This paper discusses a preliminary investigation into the use of base bleed on a production SUV using CFD analysis. The paper shows the methods used in creating the computational model and conducting the analysis, and present the findings to date. The paper shows that the reduction in drag increases as the mass flow rate of air is increased when the flow is deflected at the outlet. By controlling the turbulent wake to the rear of the vehicle, it is shown in the paper that mass flow rates of under 2kg/s can reduce drag coefficient by 8.2% with an outlet on the side of the vehicle, and that a mass flow rate of under 1.5kg/s can reduce the drag coefficient by 10.7% for an outlet on the upper section of the rear of the vehicle. The paper also discusses the feasibility of base bleed being applied to a production vehicle

Measurement of retinal vessel widths from fundus images based on 2-D modeling

Changes in retinal vessel diameter are an important sign of diseases such as hypertension, arteriosclerosis and diabetes mellitus. Obtaining precise measurements of vascular widths is a critical and demanding process in automated retinal image analysis as the typical vessel is only a few pixels wide. This paper presents an algorithm to measure the vessel diameter to subpixel accuracy. The diameter measurement is based on a two-dimensional difference of Gaussian model, which is optimized to fit a two-dimensional intensity vessel segment. The performance of the method is evaluated against Brinchmann-Hansen's half height, Gregson's rectangular profile and Zhou's Gaussian model. Results from 100 sample profiles show that the presented algorithm is over 30% more precise than the compared techniques and is accurate to a third of a pixel

Late Turonian ammonites from Haute-Normandie, France

Upper Turonian chalks of Haute-Normandie yield a distinctive ammonite fauna within the Subprionocyclus neptuni ammonite Zone and the Plesiocorys (Sternotaxis) plana echinoid Zone. Well-localised material all comes from the phosphatic fauna of the Senneville 2 Hardground that marks the boundary between the Formation de Senneville and the Életot Member of the succeeding Formation de Saint-Pierre-en-Port. The association is dominated by Lewesiceras mantelli Wright and Wright, 1951, accompanied by Mesopuzosia mobergi (de Grossouvre, 1894), Lewesiceras woodiWright, 1979, Subprionocyclus hitchinensis (Billinghurst, 1927), Subprionocyclus branneri (Anderson, 1902), Subprionocyclus normalis (Anderson, 1958), Allocrioceras nodiger (F. Roemer, 1870), Allocrioceras billinghursti Klinger, 1976, Hyphantoceras reussianum (d’Orbigny, 1850), Sciponoceras bohemicum bohemicum (Fritsch, 1872), and Scaphites geinitzii d’Orbigny, 1850. The fauna represents the Hyphantoceras reussianum Event of authors, elements of which have been recognised on the north side of Tethys from Northern Ireland to the Mangyschlak Mountains of western Kazakstan, a distance of more than 3,500 kilometres

Trans-Tethyan correlation of the Lower–Middle Cenomanian boundary interval; southern England (Southerham, near Lewes, Sussex) and Douar el Khiana, northeastern Algeria

A 480 m section of marls with widely separated levels of nodular limestone in the Fahdene Formation north of Bou Khadra in Tebessa Province, northeastern Algeria, spans the Lower/Middle Cenomanian boundary. A total of 30 ammonite species are present, of which two: Forbesiceras reversum and Calycoceras (Newboldiceras) algeriense are new. The fauna allows recognition of the Northwest European upper Lower Cenomanian Mantelliceras dixoni Zone, the succeeding lower Middle Cenomanian Cunningtoniceras inerme Zone, the Acanthoceras rhotomagense Zone and its subzones of Turrilites costatus and Turrilites acutus. The sequence of index species occurs in the same order in both north-eastern Tunisia and the Southerham Grey Pit in Sussex (and indeed elsewhere in North-west Europe), indicating these to be robust assemblage zones and subzones that can be recognised on both the north and south sides of the Tethys. Other occurrences of taxa that are common in both sections and regions are markedly different, and include the co-occurrence of Cunningtoniceras inerme (Pervinquière, 1907) with Acanthoceras rhotomagense (Brongniart, 1822) in the costatus Subzone in north-eastern Algeria and central Tunisia, the extension of Acompsoceras renevieri (Sharpe, 1857) into the lower Middle Cenomanian in north-eastern Tunisia, whilst the acme of Turrilites scheuchzerianus Bosc, 1801, is in the dixoni Zone in Northwest Europe, and in the inerme Zone in northeasten Algeria and adjacent parts of Central Tunisia. These differences are not a result of collection failure or non-preservation, but must rather reflect environmental controls on occurrence and abundance

Optic nerve head segmentation

Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 /spl mu//pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred image

Panax ginseng has no effect on indices of glucose regulation following acute or chronic ingestion in healthy volunteers

In the absence of effective pharmacotherapy for diabetes there has been an increase in the use of, and research into, alternative treatment strategies. These include exercise, dietary interventions and the use of supplements including extracts of ginseng. Two separate, placebo-controlled, double-blind, cross-over studies investigating the effects of chronic ingestion of Panax ginseng (study 1 used G115, study 2 used Cheong Kwan Jang) on glycated Hb (HbA1c; study 1, n 18; study 2, n 11), fasting plasma insulin (study 1, n 17; study 2, n 12), fasting plasma glucose and postprandial response (following breakfast) (study 1, n 23; study 2, n 14) in healthy volunteers are reported. In both studies it was found that Panax ginseng had no effect on any gluco-regulatory parameter investigated. These results are not consistent with those reported for a diabetic sample (albeit using slightly different outcomes). These results would suggest that chronic use of Panax ginseng by non-diabetic individuals will have little long-term effect on glucose regulation. The benefits to glucose regulation associated with long-term ginseng use may only be present in populations with compromised glucose control; however, further research is needed to confirm such a speculation

Spin-gap opening accompanied by a strong magnetoelastic response in the S=1 magnetic dimer system Ba3BiRu2O9

Neutron diffraction, magnetization, resistivity, and heat capacity measurements on the 6H-perovskite Ba3BiRu2O9 reveal simultaneous magnetic and structural dimerization driven by strong magnetoelastic coupling. An isostructural but strongly displacive first-order transition on cooling through T*=176 K is associated with a change in the nature of direct Ru-Ru bonds within Ru2O9 face-sharing octahedra. Above T*, Ba3BiRu2O9 is an S=1 magnetic dimer system with intradimer exchange interactions J0/kB=320 K and interdimer exchange interactions J'/kB=-160 K. Below T*, a spin-gapped state emerges with \Delta\approx220 K. Ab initio calculations confirm antiferromagnetic exchange within dimers, but the transition is not accompanied by long range-magnetic order.Comment: 5 pages, 5 figures, accepted by Physical Review

Generic and customised digital image enhancement filters for the visually impaired

AbstractThis study compares the effectiveness of various image enhancement filters for improving the perceived visibility of coloured digital natural images for people with visual impairment. Generic filters were compared with Peli’s adaptive enhancement and adaptive thresholding and custom-devised filters based on each subject’s contrast sensitivity loss. Subjects with low vision made within filter rankings followed by between filter ratings. In general, subjects preferred filters with lower gains. Unsharp masking resulted in a significant increase in perceived visibility for some image types (p⩽0.05) while Peli’s adaptive enhancement, edge enhancement and histogram equalization resulted in borderline improvements. Adaptive thresholding and the custom devised filter did not result in overall improvements in perceived visibility