scholarly journals Effect of Spatial Scale on Modeling and Predicting Mean Cavity Tree Density: A Comparison of Modeling Methods

2012 ◽  
Vol 02 (04) ◽  
pp. 219-224
Author(s):  
Stephen S. Lee ◽  
Zhaofei Fan
Keyword(s):  
Spatial Scale ◽  
Tree Density ◽  
Modeling Methods ◽  
Cavity Tree

Invariant Visual Responses From Attentional Gain Fields

1997 ◽  
Vol 77 (6) ◽  
pp. 3267-3272 ◽  
Author(s):  
Emilio Salinas ◽  
L. F. Abbott
Keyword(s):  
Spatial Scale ◽  
Computer Modeling ◽  
Visual Stimuli ◽  
Receptive Fields ◽  
Gain Modulation ◽  
Visual Responses ◽  
Translation Invariant ◽  
Modeling Methods ◽  
V4 Neurons ◽  
Substantial Degree

Salinas, Emilio and L. F. Abbott. Invariant visual responses from attentional gain fields. J. Neurophysiol. 77: 3267–3272, 1997. Inferotemporal (IT) neurons exhibit a substantial degree of invariance with respect to translation of images used as visual stimuli. Through theoretical and computer-modeling methods, we show how translation-invariant receptive fields, like those of IT neurons, can be generated from the responses of V4 neurons if the effects of attention are taken into account. The model incorporates a recently reported form of attention-dependent gain modulation in V4 and produces IT receptive fields that shift so they are centered at the point where attention is directed. Receptive fields of variable, attention-controlled spatial scale are obtained when the mechanism is extended to scale-dependent attentional gain fields. The results indicate that gain modulation may play analogous roles in the dorsal and ventral visual pathways, generating transformations from retinal coordinates to body- and object-centered systems, respectively.

The role of local cavity tree density in the selection of den sites by female fishers (Pekania pennanti) in northern Minnesota

2020 ◽  
Vol 50 (8) ◽  
pp. 742-750
Author(s):  
Sergey S. Berg ◽  
John D. Erb ◽  
Vincent T. Spaid ◽  
Daniel L. Dewey ◽  
Pamela L. Coy ◽  
...  
Keyword(s):  
Conditional Logistic Regression ◽  
Large Diameter ◽  
Tree Density ◽  
Breast Height ◽  
Pekania Pennanti ◽  
Potential Benefits ◽  
Natural Range ◽  
Cavity Tree ◽  
Selection Of

Although several studies have evaluated fisher (Pekania pennanti (Erxleben, 1777)) selection of den structures across their natural range, the role of other nearby trees with suitable cavities that can be used by female fishers for subsequent maternal dens has not been explored. We used conditional logistic regression to describe selection of natal and maternal dens by female fishers in northern Minnesota, United States, and to determine if the density of other cavity trees surrounding a specific tree influences this selection. Our results indicate that cavity density was an important predictor of whether a tree was used as a den site by female fishers. The apparent condition (i.e., live, declining, or dead) and diameter at breast height of the cavity tree itself were also important for selection. These results affirm the need to retain large-diameter cavity trees, illustrate the potential benefits of retaining them in high-density patches, and caution against creating a landscape with highly dispersed denning options.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

Sex-biased dispersal depends on the spatial scale in a tube-building amphipod species

2020 ◽  
Author(s):  
PA Peres ◽  
AP Ferreira ◽  
GBO Machado ◽  
M Azevedo-Silva ◽  
SGL Siqueira ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Amphipod Species

Climate Scenarios for the conterminous United States at the county spatial scale using SRES scenarios A1B and A2 and PRISM climatology

2011 ◽  
Author(s):  
David P. Coulson ◽  
Linda A. Joyce ◽  
David T. Price ◽  
Daniel W. McKenney ◽  
R. Martin Siltanen ◽  
...  
Keyword(s):  
United States ◽  
Spatial Scale ◽  
Climate Scenarios ◽  
Sres Scenarios

Evaluation of the functional tension of foreign medical student’s organisms in adapting to educational activities

2020 ◽  
pp. 755-755
Author(s):  
N. K. Smagulov ◽  
A. A. Adilbekova ◽  
N. V. Gitenis
Keyword(s):  
Mathematical Modeling ◽  
Foreign Students ◽  
Educational Process ◽  
Educational Activities ◽  
Modeling Methods ◽  
Functional Stress

The use of mathematical modeling methods allowed us to develop criteria for functional stress for assessing and predicting the level of functional stress of foreign students in the process of adaptation to the educational process.

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