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211.
212.
Z. Pizlo 《Biological cybernetics》1988,58(1):51-62
The present paper considers the relation between the shape of a triangle and probability of its recognition. An effect of triangle size on perception of its shape is examined in the first experiment. In the second the loci of eye fixations during triangle recognition task are recorded and analysed. A simulation model of the recognition process is proposed. The model is based on two main assumptions: 1. an accuracy of shape processing is related to the cortical magnification factor, 2. a subject's response depends on actual position of eye fixation. The validity of the model is verified by comparing the theoretical and experimental response distributions. Some psychophysiological implications are then discussed.A partial report of this research was given at the Annual Meeting of the Association for Research in Vision and Ophthalmology (Pizlo and Gradus-Pizlo 1986) 相似文献
213.
214.
215.
Blockage of tropoelastin secretion by monensin represses tropoelastin synthesis at a pretranslational level in rat smooth muscle cells.
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The blockage of protein secretion in the R22 cultured rat aortic smooth muscle cell strain with monensin repressed tropoelastin gene expression at the mRNA level by ca. 50-fold as measured by biosynthetic pulse-labeling, in vitro translation, and hybridization with a tropoelastin genomic DNA probe. These results suggest that tropoelastin gene expression is autoregulated, and they represent the first reported effect of monensin on gene expression. 相似文献
216.
217.
A comparative analysis of photosynthetic characteristics of hulless barley at two altitudes on the Tibetan Plateau 总被引:1,自引:0,他引:1
To determine the photosynthetic characteristics of C3 plants and their sensitivity to CO2 at different altitudes on the Tibetan Plateau, hulless barley (Hordeum vulgare L. ssp. vulgare) was grown at altitudes of 4,333 m and 3,688 m. Using gas-exchange measurements, photosynthetic parameters were simulated,
including the maximum net photosynthesis (P
max) and the apparent quantum efficiency (α). Plants growing at higher altitude had higher net photosynthetic rates (P
N), photosynthesis parameters (P
max and α) and sensitivities to CO2 enhancement than plants growing at lower altitude on the Tibetan Plateau. The enhancements of P
N, P
max, and α for plants growing at higher altitude, corresponding with 10 μmol(CO2) mol−1 increments, were approximately 0.20∼0.45%, 0.05∼0.20% and 0.12∼0.36% greater, respectively, than for plants growing at lower
altitude, respectively, where CO2 levels rose from 10 to 170 μmol(CO2) mol−1. Therefore, on the Tibetan Plateau, the changes in the photosynthetic capacities and the photosynthetic sensitivities to
CO2 observed in the C3 plants grown above 3,688 m are likely to increase with altitude despite the decreasing CO2 partial pressure. 相似文献
218.
219.
A Ia Litoshenko 《Biulleten' eksperimental'no? biologii i meditsiny》1984,97(3):299-301
The rate of mitochondrial DNA turnover was studied in the liver of adult and old rats. It was shown to decrease with aging in both the whole mitochondrial population and its heavy and light fractions. This decrease reflects the deceleration of the rate of liver mitochondrial biogenesis in old age and is considered to be a cause of energy deficiency of an old body. 相似文献
220.
M. Cycoń Z. Piotrowska-Seget J. Kozdrój 《World journal of microbiology & biotechnology》2010,26(3):409-418
Changes in microbiological characteristics in response to diazinon, applied at three different dosages of 7, 35 and 700 mg kg?1 soil, were studied in pots filled with sandy soils of different texture. The insecticide dosages corresponded to the maximum predicted environmental concentration (PEC) in field conditions and five or hundred times this rate, respectively. To ascertain these changes, activities of selected soil enzymes, numbers of some microbial populations and bacterial community structure (r/K-strategists) were determined. Acid phosphatase activity and concentrations of ammonium ions either increased or were unaffected by the diazinon dosages. In contrast, nitrate ions, alkaline phosphatase, urease and especially dehydrogenase activities decreased in both soils treated with the higher dosages of the insecticide. The diazinon treatments increased the numbers of culturable bacteria and fungi; however, N-fixing bacteria and nitrifiers (but not denitrifiers) were decreased in both soils. When the high concentration of diazinon (100-times PEC) was added to the loamy sand soil (LS), simulating an undiluted chemical spill, the bacterial community structure shifted towards domination of K-strategists over time. However, r-strategists dominated in the community exposed to the same dosage of the insecticide in the sandy loam soil (SL). Generally, SL soil characteristics were more suitable for microbial activity and growth than those of LS soil were. The results indicate that except a situation of undiluted spill diazinon seems to be a non-hazardous chemical for the culturable soil microorganisms when applied at recommended concentrations. 相似文献