Flatford Mill Field Center

1948 ◽  
Vol 10 (4) ◽  
pp. 93-96
Author(s):  
E. A. R. Ennion
Keyword(s):  
Field Center ◽  
Mill Field

Volume 1: Wraparound: Stories from the Field: Center for Effective Collaboration and Practice American Institutes for Research

2013 ◽  
Author(s):  
Kimberly Kendziora ◽  
Eric Burns ◽  
David Osher ◽  
Debra Pacchiano ◽  
Brenda Mejia
Keyword(s):  
Field Center ◽  
Effective Collaboration

Response dynamics and receptive-field organization of catfish amacrine cells

1992 ◽  
Vol 67 (2) ◽  
pp. 430-442 ◽  
Author(s):  
H. M. Sakai ◽  
K. Naka
Keyword(s):  
Receptive Field ◽  
White Noise ◽  
Amacrine Cells ◽  
Second Order ◽  
Response Dynamics ◽  
Field Center ◽  
Mean Luminance ◽  
Nonlinear Components ◽  
Receptive Field Center ◽  
Dc Potentials

1. We have applied Wiener analysis to a study of response dynamics of N (sustained) and C (transient) amacrine cells. Stimuli were a spot and an annulus of light, the luminance of which was modulated by two independent white-noise signals. First- and second-order Wiener kernels were computed for each spot and annulus input. The analysis allowed us to separate a modulation response into its linear and nonlinear components, and into responses generated by a receptive-field center and its surround. 2. Organization of the receptive field of N amacrine cells consists of both linear and nonlinear components. The receptive field of linear components was center-surround concentric and opposite in polarity, whereas that of second-order nonlinear components was monotonic. 3. In NA (center-depolarizing) amacrine cells, the membrane DC potentials brought about by the mean luminance of a white-noise spot or a steady spot were depolarizations, whereas those brought about by the mean luminance of a white-noise annulus or a steady annulus were hyperpolarizations. In NB (center-hyperpolarizing) amacrine cells, this relationship was reversed. If both receptive-field center and surround were stimulated by a spot and annulus, membrane DC potentials became close to the dark level and the amplitude of modulation responses became larger. 4. The linear responses of a receptive-field center of an N amacrine cell, measured in terms of the first-order Wiener kernel, were facilitated if the surround was stimulated simultaneously. The amplitude of the kernel became larger, and its peak response time became shorter. The same facilitation occurred in the linear responses of a receptive-field surround if the center was stimulated simultaneously. 5. The second-order nonlinear responses were not usually generated in N amacrine cells if the stimulus was either a white-noise spot or a white-noise annulus alone. Significant second-order nonlinearity appeared if the other region of the receptive field was also stimulated. 6. Membrane DC potentials of C amacrine cells remained at the dark level with either a white-noise spot or a white-noise annulus. The cell responded only to modulations. 7. The major characteristics of center and surround responses of C amacrine cells could be approximated by second-order Wiener kernels of the same structure. The receptive field of second-order nonlinear components of C amacrine cells was monotonic.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Quality Assurance Procedure for Assessing Mechanical Accuracy of a Radiation Field Center in Stereotactic Radiotherapy

2012 ◽  
Vol 68 (10) ◽  
pp. 1333-1339 ◽  
Author(s):  
Daisaku Tatsumi ◽  
Akinori Ienaga ◽  
Ryosei Nakada ◽  
Akane Yomoda ◽  
Makoto Inoue ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Radiation Field ◽  
Stereotactic Radiotherapy ◽  
Quality Assurance Procedure ◽  
Field Center

Flow-field center migration during vertical and oblique impacts

2006 ◽  
Vol 33 (1-12) ◽  
pp. 35-44 ◽  
Author(s):  
Jennifer L.B. Anderson ◽  
Peter H. Schultz
Keyword(s):  
Flow Field ◽  
Field Center ◽  
Oblique Impacts

Microcircuitry related to the receptive field center of the on-beta ganglion cell

1991 ◽  
Vol 65 (2) ◽  
pp. 352-359 ◽  
Author(s):  
E. Cohen ◽  
P. Sterling
Keyword(s):  
Receptive Field ◽  
Beta Cell ◽  
Ganglion Cell ◽  
Beta Cells ◽  
Weighting Function ◽  
Cell Array ◽  
Dendritic Field ◽  
Field Center ◽  
The Mean ◽  
Receptive Field Center

1. We have investigated the anatomic basis for the Gaussian-like receptive field center of the on-beta ("X") ganglion cell in the area centralis of cat retina. Three adjacent on-beta cells were reconstructed from electron micrographs of 279 serial sections cut vertically through a patch of retina at approximately 1 degree eccentricity. 2. All the bipolar synapses on these cells were identified, and about one-half of these were traced to type b1 bipolar cells, which formed a regular array in the plane of the retina. 3. On average, seven b1 cells contributed to a beta cell: bipolar axons near the middle of the beta dendritic field tended to give many contacts (12-33 contacts); axons near the edge of the field tended to give few contacts (3-4 contacts). 4. Each b1 cell collected from four to seven cones, and the mean number of cones converging through the b1 array to a beta cell was 30. 5. Assuming equal effectiveness for all b1----beta cell synapses, a spatial weighting function was derived from these results. The mean radius of this function at 1/e amplitude for three beta cells was 18.0 +/- 1.1 (SD) microns. This is considerably narrower than the corresponding measurements of the beta cell receptive field center (28 +/- 3 microns) at this eccentricity. 6. It is concluded, in agreement with previous work, that all cones encompassed by the beta cell's dendritic field and those slightly beyond it connect directly to the beta cell via the b1 bipolar cell array. However, the center of the beta cell receptive field is still broader by approximately 60%. This suggests that pooling of cone signals may occur at the level of the outer plexiform layer.

The Humboldt high magnetic field center at Berlin

2001 ◽  
Vol 294-295 ◽  
pp. 568-573 ◽  
Author(s):  
M. von Ortenberg ◽  
N. Puhlmann ◽  
I. Stolpe ◽  
H.-U. Mueller ◽  
A. Kirste ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Field Center
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