A simple extension to ray tracing is presented that creates visually plausible “soft” shadows with little extra computation. Although these soft shadows are approximate, they are robust and have penumbra widths that behave in a believable way, including accurate placement of singularities where penumbra width is zero. The method has continuous behavior in space and time, so it is appropriate fo...

We analyse a sunspot simulation in an effort to understand the origin of convective instabilities giving rise penumbral and umbral distinct regimes. applied criterion from Gough \& Tayler (1966), accounting for stabilising effect vertical magnetic field investigate MURaM simulation. find: (1) highly unstable shallow layer right beneath surface extending all over box which convection is triggere...

Acute ischemia produces dynamic changes in labile metabolites. To capture snapshots of such acute metabolic changes, we utilized focused microwave treatment to fix metabolic flow in vivo in hearts of mice 10 min after ligation of the left anterior descending artery. The left ventricle was subdivided into short-axis serial slices and the metabolites were analyzed by capillary electrophoresis mas...

The high-quality simulation of the penumbra effect in real-time shadows is a challenging problem in shadow mapping. The existing shadow map filtering techniques are prone to aliasing and light leaking artifacts which decrease the shadow visual quality. In this paper, we aim to minimize both problems with the Euclidean distance transform shadow mapping. To reduce the perspective aliasing artifac...

OBJECTIVE To evaluate interstitial glycerol as a marker of ischaemia by studying the changes in glycerol in direct relation to changes in regional cerebral metabolic rate of oxygen (CMRO(2)), the lactate/pyruvate ratio (LP ratio), and glutamate. METHODS Transorbital 2 hour middle cerebral artery occlusion (MCAO) was performed in eight monkeys, which were studied with continuous microdialysis ...

INTRODUCTION Therapy in acute ischemic stroke can only be effective as long as potentially salvageable tissue is present within the brain area affected by the blood flow disturbance. Therefore, the identification of the penumbra and the distinction of this potentially reversible condition from irreversibly damaged tissue are of utmost importance for the initiation of treatment strategies. Irrev...

BACKGROUND AND PURPOSE Besides classic criteria, cerebral perfusion imaging could improve patient selection for thrombolytic therapy. The purpose of this study was to compare quantitative perfusion CT imaging and qualitative diffusion- and perfusion-weighted MRI (DWI and PWI) in acute stroke patients at the time of their emergency evaluation. METHODS Thirteen acute stroke patients underwent p...

Physical and dosimetric characteristics of HDMLC were studied for SRS6, 6, and 10 MV X-rays from Novalis Tx. This in-built tertiary collimator consists of 60 pairs (32 × 0.25 cm; 26 × 0.5 cm and 2 × 0.7 cm) of leaves. Properties of HDMLC studied included alignment, readout and radiation field congruence, radiation penumbra, accuracy and reproducibility of leaf position and gap width, static and...

The filamentary structure of a sunspot penumbra is believed to be magnetoconvective in origin. In the outer penumbra there is a difference in inclination of up to 30 Y40 between the magnetic fields associated with bright and dark filaments, and the latter fields plunge downward below the surface toward the edge of the spot.We have proposed that these fields are dragged downward bymagnetic pumpi...

Identification of the ischemic penumbra in the acute stroke clinical setting is an important goal for stroke researchers and clinicians. Various models for imaging the penumbra with MRI have been proposed, including the pioneering diffusion-perfusion mismatch model and later multivariate approaches. A number of multicenter clinical trials are now under way to test these models and confirm the u...