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Stereoscopic shape judgements can be modified by the addition of texture cues. This paper examines the properties of texture that are responsible for this effect. When a three-dimensional curved surface is projected onto a two-dimensional image, changes in surface orientation result in gradients of texture element size (or area), shape (compression) and density in the image. Manipulating each of these gradients independently we found that 97% of the variance in the results could be accounted for by the compression gradient. When the texture pattern corresponds to a highly anisotropic texture on the object's surface, shape-from-texture becomes ineffective. These results suggest that human shape-from-texture proceeds under the assumption that textures are statistically isotropic, and not that they are homogeneous.  相似文献   
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In a search for new restriction endonucleases type II, among forty bacterial strains of the Bacillus genus two strains producing site-specific endonucleases have been found. Endonucleases BbvAIII and BspFI, isolated from B. brevis BLM B-677 and B. species F, are shown to be true isoschisomers of BspMII (Kpn2I) and Sau3AI, respectively.  相似文献   
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Fibrin appears to be a multi-potential component of atherogenesis, intervening at virtually all stages of lesion development. Fibrin and microthrombus deposition on normal intima is associated with endothelial disruption and intimal oedema, and oedema is a primary characteristic of early proliferative lesions. Fibrin strands on or in the intima encourage smooth muscle cell (SMC) migration and proliferation, and contribute to the growth of plaques. Fibrin also provides a continuing source of fibrin degradation products (FDP), and these have mitogenic activity which will sustain SMC proliferation in growing plaques, and act as chemoattractants for blood leucocytes. Accumulation of the lipid core in fibrous plaques may also be influenced by fibrin which appears to bind the lipoprotein Lp(a) with high affinity, thereby immobilizing its lipid moiety within the lesion.  相似文献   
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Specific features of intrathoracic tuberculosis course, outcomes and treatment are outlined for 109 children. In 59 of them tuberculosis was associated with nonspecific respiratory diseases (NRD). 28.8%, 25.4%, 18.6, 27.2% of patients had cystic hypoplasia, chronic hypoplasia, recurrent pneumonia, recurrent bronchitis, respectively. Complicated course of tuberculosis occurred 2 times more frequently in its combination with NRD (71.2%). Destruction and discharge of bacteria were recorded in 49.2 and 47.5% of patients, respectively. Undulating running was 3.4 and side effects 1.6 times more frequent. Tuberculous children with NRD need longer antituberculous therapy using wide-spectrum antibiotics, symptomatic and exercise treatment, massage, surgical intervention if necessary. Complete resolution of lung lesions in NRD children were seen 4.8 times less frequently. In case of late diagnosis 54% of them retained residual changes in the form of lung tissues fibrosis, calcified foci in the lungs and lymph nodes.  相似文献   
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