The difference between integral and separable interaction of dimensions is a classic problem in cognitive psychology (Garner 1970, American Psychologist, 25: 350-358, Shepard 1964, Journal of Mathematical Psychology, 1: 54-87) and remains an essential component of most current experimental and theoretical analyses of category learning (e.g. Ashby and Maddox 1994, Journal of Mathematical Psychology, 38: 423-466, Goldstone 1994, Journal of Experimental Psychology: General , 123: 178-200, Kruschke 1993, Connection Science, 5: 3-36, Melara et al. 1993, Journal of Experimental Psychology: Human Perception & Performance, 19: 1082-1104, Nosofsky 1992, Multidimensional Models of Perception and Cognition, Hillsdale NJ: Lawrence Erlbaum). So far the problem has been addressed through post hoc analysis in which empirical evidence of integral and separable processing is used to fit human data, showing how the impact of a pair of dimensions interacting in an integral or a separable manner enters into later learning processes. In this paper, we argue that a mechanistic connectionist explanation for variations in dimensional interactions can provide a new perspective through exploration of how similarities between stimuli are transformed from physical to psychological space when learning to identify, discriminate and categorize them. We substantiate this claim by demonstrating how even a standard backpropagation network combined with a simple image-processing Gabor filter component provides limited but clear potential to process monochromatic stimuli that are composed of integral pairs of dimensions differently from monochromatic stimuli that are composed of separable pairs of dimensions. Interestingly, the responses from Gabor filters are shown already to capture most ofthe dimensional interaction, which in turn can be operated upon by the neural network during a given learning task. In addition, we introduce a basic attention mechanism to back-propagation that gives it the ability to attend selectively to relevant dimensions and illustrate how this serves the model in solving a filtration versus condensation task (Kruschke 1993, Connection Science, 5: 3-36). The model may serve as a starting point in characterizing the general properties of the human perceptual system that causes some pairs of physical dimensions to be treated as integrally interacting and other pairs as separable. An improved understanding of these properties will aid studies in perceptual and category learning, selective attention effects and influences of higher cognitive processes on initial perceptual representations. 相似文献
This study evaluated the effects of a burnout prevention program based on insights from transpersonal psychology, notably psychosynthesis. It examined the effects of the program on burnout, happiness, spirituality, emotional intelligence, and relative deprivation with respect to one's career. Thirty-eight individuals, mostly with a background in engineering, participated in a 10-day program over 3 months. A comparison group of similar age and work experience was recruited of colleagues from the same firms and departments. Both groups filled out questionnaires at 3 time points: before the start of the program, immediately after the program (3 months later), and 9 months later. Results showed that a psychosynthesis-based prevention program might be an effective instrument in reducing burnout and enhancing happiness, emotional intelligence, and feelings of spirituality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Tool performance of conventional tools is poor and a major constraint when used in milling titanium alloys at elevated cutting speeds. At these high cutting speeds, the chemical and mechanical properties of Ti6Al4V cause complex wear mechanisms. In this paper, a fine-grain polycrystalline diamond (PCD) end mill tool was tested, and its wear behavior was studied. The performance of the PCD tool has been investigated in terms of tool life, cutting forces, and surface roughness. The PCD tool yielded longer tool life than a coated carbide tool at cutting speeds above 100?m/min. A slower wear progression was found with an increase in cutting speeds, whereas the norm is an exponential increase in tool wear at elevated speeds. Observations based on scanning electron microscope (SEM) and energy dispersive spectroscopy (EDAX) analysis suggest that adhesion of the workpiece is the wear main type, after which degradation of the tools accelerates probable due to the combined effect of high temperature degradation coupled with abrasion. 相似文献
Affective priming studies have demonstrated that subliminally presented prime words can exert an influence on responses towards positive or negative target stimuli. In the present series of experiments, it was investigated whether these findings can be extended to pictorial stimuli. Ideographically selected positive, neutral, and negative picture primes that were sandwich-masked immediately preceded positive or negative target pictures (Experiment 1) or words (Experiments 2 & 3). Evaluative categorization responses to these target stimuli were significantly influenced by the valence of the prime. First, it was demonstrated that high anxious participants were selectively slowed when the subliminally presented prime was negative (Experiments 1 & 2). Second, the affective congruence between primes and targets also exerted an influence on the responses, but in a direction that is opposite to what is typically observed in affective priming research. These reverse priming effects are situated within a series of recent similar findings, and implications for theories of affective priming are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The neutral lipid and phospholipid compositions of purified sinusoidal (fat-storing, endothelial and Kupffer) cells, parenchymal
cells and liver homogenates were determined by thin layer chromatography. In addition, the retinoid content of the same purified
cell populations was determined by high performance liquid chromatography. From each cell type, both a lipid droplet fraction
and a pellet fraction (containing the majority of the remaining cell organelles) were prepared by differential centrifugation.
Electron microscopic analysis showed that lipid droplets isolated from fat-storing cells were larger (up to 8 μm) than those
isolated from parenchymal cells (up to 2.5 μm). Moreover, the parenchymal lipid droplets seemed to be surrounded by a membranous
structure, while the fat-storing lipid droplets seemed not to be. Both fat-storing and parenchymal cells contained high concentrations
of neutral lipids, 57.9 μg and 71.0 μg/106 cells, respectively, while endothelial and Kupffer cells contained only 8.6 μg and 13.8 μg/106 cells of neutral lipids, respectively. Sixty-five percent of fat-storing cell lipid droplet fractions comprised esters of
retinol and cholesterol. This combined ester fraction contained mainly retinyl esters. In addition, considerable quantities
(20%) of triglycerides were present. Parenchymal cell lipid droplet fractions comprised triglycerides (62%) and cholesteryl
esters (up to 30%). The pellet fractions prepared from all four cell types consisted mainly of cholesterol (41–67%) and free
fatt acids (20–28%). The phospholipid content was much higher in parenchymal cells than in the sinusoidal liver cell types.
The relative proportions of the four major phospholipid classes were comparable in all liver cell types analyzed. It is concluded
that parenchymal cell lipid droplets comprised mainly triglycerides and cholesteryl esters, which is in agreement with the
function of parenchymal cells in lipid metabolism. Fat-storing cell lipid droplets consisted of retinyl esters and triglycerides,
which correlates well with their function in retionid storage and metabolism. 相似文献
The inherent properties of poly(lactide), a biocompatible and biodegradable polymer, are concurrently improved by the incorporation of a small amount of surface functionalized carbon nanotubes. A new method has been used to functionalize the CNTs' outer surface with hexadecylamine. A composite of PLA with functionalized CNTs has been prepared by melt‐extrusion. FT‐IR spectroscopy, Raman spectroscopy, DSC, and optical microscopy are used to investigate the thermal and mechanical property improvement mechanism in f‐CNTs containing PLA composite.
Silicon is one of the most important elements in the current age of the anthropocene. It has numerous industrial applications,
and supports a high-tech multi-billion Euro industry. Silicon has a fascinating biological and geological cycle, interacting
with other globally important biogeochemical cycles. In this review, we bring together both biological and geological aspects
of the silicon cycle to provide a general, comprehensive review of the cycling of silicon in the environment. We hope this
review will provide inspiration for researchers to study this fascinating element, as well as providing a background environmental
context to those interested in silicon. 相似文献