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101.
Deformable template models and Markov chain Monte Carlo methods are used for analysing a space-time process of intracoronary ultrasound images in order to detect the artery contour and various other characteristics as a function of time. 相似文献
102.
Using cellular automata images and pseudo amino acid composition to predict protein subcellular location 总被引:6,自引:0,他引:6
Summary. The avalanche of newly found protein sequences in the post-genomic era has motivated and challenged us to develop an automated
method that can rapidly and accurately predict the localization of an uncharacterized protein in cells because the knowledge
thus obtained can greatly speed up the process in finding its biological functions. However, it is very difficult to establish
such a desired predictor by acquiring the key statistical information buried in a pile of extremely complicated and highly
variable sequences. In this paper, based on the concept of the pseudo amino acid composition (Chou, K. C. PROTEINS: Structure, Function, and Genetics, 2001, 43: 246–255), the approach of cellular automata image is introduced to cope with this problem. Many important features,
which are originally hidden in the long amino acid sequences, can be clearly displayed through their cellular automata images.
One of the remarkable merits by doing so is that many image recognition tools can be straightforwardly applied to the target
aimed here. High success rates were observed through the self-consistency, jackknife, and independent dataset tests, respectively. 相似文献
103.
B. Ronacher U. Duft 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,178(6):803-812
Currently two hypotheses exist as to how an insect's CNS stores and compares learned visual images: storage as a photograph-like eidetic image (template-hypothesis), and storage as a set of features extracted by the visual system (parameter-hypothesis). An important criterion for deciding between these two hypotheses is the generalization of a learned pattern to other patterns. We therefore trained bees to patterns presented on a vertical screen and to discriminate between either a black triangle and a ring-pattern (training A, B), or a black disc and an outline triangle (training C), and then tested for a possible generalization of the learned patterns to a variety of other patterns. Several results obtained that way (e.g. the transfer test, column 2 in Fig. 1a, or Fig. 3) seem to indicate that the bees indeed do generalize a learned pattern to other patterns, and hence appear to support the parameter-hypothesis. Quite unexpectedly, however, it turned out that the same results can also be explained by a template matching mechanism. In simulating an image matching strategy we used a similarity function that had been successfully applied to pattern discrimination data obtained in tetheredly flying fruitflies, Drosophila. This similarity function assumes that the insect evaluates the ratio between the overlap of an actual retinal image with the stored template and the total area of the actual retinal image (see Fig. 5). It is able to describe the bulk of our data. Interestingly, the training situation appears to have an influence on the weight attributed by the bee to different parts of the template. Such a situation-dependent weighting might indicate a first stage of parameter extraction.Abbreviations
TR +
positive training shape
-
TR
negative training shape 相似文献
104.
Stuart A. Marks 《Human ecology: an interdisciplinary journal》1977,5(1):1-36
This article describes the hunting tactics and prey selection of the Valley Bisa, a matrilineal, subsistence-oriented society in the Luangwa Valley of Zambia. Although Valley Bisa hunters explain their behavior in their own idioms, many of their tactics, including the stimuli for and timing of hunts, the circular morphology of their hunting patterns, and randomized searches, appear functionally related to the behavior and ecology of their prey. The effects of outlawing traditional harvest techniques and the imposition and enforcement of external constraints on Valley Bisa hunting patterns are discussed. Data on habitats, density of cover, wind direction, species, and initial distance to prey from 50 hunts, in which 16 mammals were killed, are compared and related to success and failure of stalking attempts. Graphs, comparing the numbers of observations for each of four variables with the frequency of stalking attempts, illustrate the cultural style of predation for this group of hunters.This article was initially presented as part of my contribution to a graduate seminar, Public Management of the African Environment, African Studies Program, Indiana University, October 9, 1975. I wish to thank Professor J. Gus Liebenow for extending the invitation to participate in this program. 相似文献
105.
James A. Simmons Cynthia F. Moss Michael Ferragamo 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(4):449-470
1. FM echolocating bats (Eptesicus fuscus) were trained to discriminate between a two-component complex target and a one-component simple target simulated by electronically-returned echoes in a series of experiments that explore the composition of the image of the two-component target. In Experiment I, echoes for each target were presented sequentially, and the bats had to compare a stored image of one target with that of the other. The bats made errors when the range of the simple target corresponded to the range of either glint in the complex target, indicating that some trace of the parts of one image interfered with perception of the other image. In Experiment II, echoes were presented simultaneously as well as sequentially, permitting direct masking of echoes from one target to the other. Changes in echo amplitude produced shifts in apparent range whose pattern depended upon the mode of echo presentation. 2. Eptesicus perceives images of complex sonar targets that explicitly represent the location and spacing of discrete glints located at different ranges. The bat perceives the target's structure in terms of its range profile along a psychological range axis using a combination of echo delay and echo spectral representations that together resemble a spectrogram of the FM echoes. The image itself is expressed entirely along a range scale that is defined with reference to echo delay. Spectral information contributes to the image by providing estimates of the range separation of glints, but it is transformed into these estimates. 3. Perceived absolute range is encoded by the timing of neural discharges and is vulnerable to shifts caused by neural amplitude-latency trading, which was estimated at 13 to 18 microseconds per dB from N1 and N4 auditory evoked potentials in Eptesicus. Spectral cues representing the separation of glints within the target are transformed into estimates of delay separations before being incorporated into the image. However, because they are encoded by neural frequency tuning rather than the time-of-occurrence of neural discharges, the perceived range separation of glints in images is not vulnerable to amplitude-latency shifts. 4. The bat perceives an image that is displayed in the domain of time or range. The image receives no evident spectral contribution beyond what is transformed into delay estimates. Although the initial auditory representation of FM echoes is spectrogram-like, the time, frequency, and amplitude dimensions of the spectrogram appear to be compressed into an image that has only time and amplitude dimensions.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
106.
Franz Thiébaut Jon B. Reitan Kari Feren Jean Paul Rigaut Albrecht Reith 《Cell and tissue research》1986,246(1):1-6
Summary The simultaneous use of a silver-staining technique, backscattered electron imaging and stereo-tilts has made it possible to visualize the spatial distribution of cell nuclei in the stretched epithelium of the bladder of mice. This study has led to the observation that a structural organization resembling the epidermal proliferative unit, previously found in the skin exists also in bladder epithelium. However, the proliferative unit in the bladder was different in that it contained a higher number of cells per unit, and an absence of columns of inactive squamous cells. These findings may indicate that epidermal proliferative unit-like structures represent a common form of organization in some epithelia. 相似文献
107.
Autotomy is the ability to spontaneously self‐amputate a limb or other appendage, often as a reflexive action. This limb amputation typically occurs as a specialized defensive response to an attack from a predator and thereby enables the prey to escape from predation. Despite the benefits of escape, autotomized organisms lose the body part and its associated function. Here, we investigated the jumping behavior and performance of one‐leg‐autotomized and intact rice grasshoppers, Oxya yezoensis, to examine changes in jumping behavior after autotomy. The take‐off elevation of autotomized grasshoppers was 7.8° lower than in intact grasshoppers, resulting in nearly a 45° angle of take‐off, which maximized the jumping distance. Kinematic analyses of the jumping manner revealed that the angle of the femur during jumping differed between intact and autotomized grasshoppers, suggesting that the grasshoppers behaviorally change the take‐off elevation after autotomy. According to analyses of jumping performance, the degree of decline in performance differed between horizontal distance and vertical height. Even though they jumped on only one hind leg, one‐leg‐autotomized grasshoppers realized 69% performance along a horizontal distance relative to intact grasshoppers. In contrast, autotomized grasshoppers realized only a 44% performance in vertical height compared to intact grasshoppers. The difference in take‐off elevation between autotomized and intact grasshoppers is likely related to the observed difference in the magnitude of the decline in performance between horizontal distance and vertical height. These results suggest that rice grasshoppers may alter their take‐off elevation after limb autotomy to minimize the reduction in jumping distance. 相似文献
108.
109.
Guilhem Brunel Philippe Borianne Gérard Subsol Marc Jaeger Yves Caraglio 《Annals of botany》2014,114(4):829-840