What makes a good teacher? The relative importance of mathematics teachers' cognitive ability, personality, knowledge, beliefs, and motivation for instructional quality.

Background: Teachers differ substantially in their instructional performance in the classroom. Thus, researchers and policymakers are interested in how these differences can be explained and how the instruction provided by low-performing teachers can be improved. Previous research has focused either on generic (cognitive ability and personality) or profession-specific (professional knowledge, beliefs, and motivation for teaching) teacher characteristics as predictors of instructional quality but their relative importance has not yet been tested.

Evaluation of Dose-Staged Gamma Knife Radiosurgical Treatment Method for High-Risk Brain Metastases.

Objectives: The study aim was to evaluate the utility of 2-fraction, dose-staged Gamma Knife radiosurgery (GKRS) in patients with large, high-risk brain metastases (BMs).

Methods: A total of 63 large BMs in eloquent areas in 61 patients were treated with GKRS in 2 reduced doses. Treatment planning was conducted on the 50% isodose line and included the whole tumor volume as seen on T1 contrast-enhanced and T2-weighted magnetic resonance imaging sections.

Perception of light source distance from shading patterns.

Varying the distance of a light source from an object alters both the intensity and spatial distribution of surface shading patterns. We tested whether observers can use such cues to infer light source distance. Participants viewed stereoscopic renderings of rough objects with diffuse and glossy surfaces, which were illuminated by a point source at a range of distances.

The tilted Hermann grid illusion: 'illusory spots' versus 'phantom bands'.

The Hermann grid illusion became a cause célèbre, when it was reported that small figural changes from straight to curved bars abolish the dark illusory spots. We demonstrate that this is not an all-or-none effect; rather, the visual system tolerates some tilt/curviness. We transformed straight and curved Hermann grids to rhombic Motokawa grids by gradually tilting the horizontal bars.

Flattening filter free beams in SBRT and IMRT: dosimetric assessment of peripheral doses.

Purpose: Recently, there has been a growing interest in operating medical linear accelerators without a flattening filter. Due to reduced scatter, leaf transmission and radiation head leakage a reduction of out-of-field dose is expected for flattening filter free beams. The aim of the present study was to determine the impact of unflattened beams on peripheral dose for advanced treatment techniques with a large number of MUs.