One of the most striking feature of primate V1 is a topographic ordering of receptive fields. Previous models of topographic map formation (e.g., [1]) pose topography as a constraint on receptive-field formation. Optimization techniques maximize information between visual inputs and outputs [2], and produce receptive fields strikingly similar to those in V1, but not topography. Neural network i...

We present a technique for planning and verification of craniospinal treatment with the patient in the supine position. Treatment delivery and verification is streamlined through the use of modern imaging techniques. Treatments use two lateral brain fields abutted to a single or pair of posterior spine fields. Treatment delivery is simplified by aligning all isocenters in the anterior-posterior...

We investigated the receptive fields of principal cells from the cat's lateral geniculate nucleus cells. About 20% of the X type neurones showed clear nonlinearities of summation when stimulated by two simultaneously onset, small bars of light. The possible source of this nonlinearity was studied on a specially designed model of a one-layer neuronal network with inhibitory, recurrent interactio...

Ahwas sandstone and Kalhur evaporate members are two main constituents of the best reservoir unit of Zagros region, i.e. Asmari Formation. Poorly cemented to loose nature of the sandstone member and it’s well textural maturity provide highly porous and permeable zones, whereas highly compacted nature of the evaporate member provide impermeable zones in the reservoir. This paper aims to study th...

PURPOSE The aim of this study was to combine a set of methods for use of radiochromic film dosimetry, including calibration, correction for lateral effects and a proposed triple-channel analysis. These methods can be applied to GAFCHROMIC EBT3 film dosimetry for radiation field analysis and verification of IMRT plans. METHODS A single-film exposure was used to achieve dose calibration, and th...

this research was conducted in a part of the dry farming lands of the southern guilan province, aimed at examining the impact of tillage erosion on the soil displacement and consequently its productivity. in order to achieve the research aims, 18 sampling points were spotted in some different locations of the landscape in seven adjacent fields, based on the adjacency to the field ridges (border...

The cerebral cortex of the cat contains between 1 and 2 dozen representations of the visual field with different functional specializations. Six visual field maps lie along both banks of the suprasylvian sulcus, lateral and anterior to the visual areas in the occipital cortex. We have studied single-unit receptive field properties and their global organization across the visual field in 2 of th...

The hippocampus is thought to be involved in episodic memory in humans. Place cells of the rat hippocampus offer a potentially important model system to understand episodic memory. However, the difficulties in determining whether rats have episodic memory are profound. Progress can be made by considering the hippocampus as a computational device that presumably performs similar transformations ...

PURPOSE To investigate the use of a commercially available video-based EPID for in vivo dosimetry during treatment of prostate cancer patients. METHODS For 10 prostate cancer patients, the inter-fraction variation within measured portal dose images (PDIs) was assessed and measured PDIs were compared with corresponding predicted PDIs based on the planning CT scan of the patient. RESULTS For ...

The effects of a transverse magnetic field on an in-line side-coupled 6 MV linear accelerator are given. The results are directly applicable to a linac-MR system used for real-time image guided adaptive radiotherapy. Our previously designed end-to-end linac simulation incorporated the results from the axisymmetric 2D electron gun program EGN2w. However, since the magnetic fields being investiga...