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941.
Functional architecture of auditory cortex   总被引:13,自引:0,他引:13  
Three complementary approaches demonstrate new types of organization in rodent, feline and primate auditory cortex, as well as differences in processing between auditory and visual cortex. First, connectional work reveals patterns of thalamocortical and corticocortical input unique to the auditory cortex. Second, physiological studies find multiple, interleaved auditory processing modules related to corticocortical connections and embedded in the isofrequency gradient. Third, functional analyses demonstrate independent processing streams for sound localization and identification analogous to the 'what' and 'where' streams in visual cortex, although the modular arrangements are modality-specific. Taken together, these data show that the auditory cortex has common and unique functional substrates.  相似文献   
942.
Summary Types of root infection were analysed in healthy dominant and sub-dominant plants of zonal and azonal vegetation above the timberline in the Central and Northern Calcareous Alps of Austria. In the open nival zone vegetation, infection by fungi of the Rhizoctonia type was predominant, vesicular-arbuscular mycorrhizal infection, which was mostly of the fine endophyte (Glomus tenuis) type, being light and mainly restricted to grasses in closed vegetation patches. More extensive Glomus tenuis infection was found in the alpine grass heath, but in Carex, Rhizoctonia was again the most important fungus. The ericaceous plants of the dwarf shrub heath have typical ericoid infection, but quantitative analysis reveals a decrease of infection intensity with increase of altitude. The possible function of the various types of root infection are discussed, and the status of Rhizoctonia as a possible mycorrhizal fungus is considered.  相似文献   
943.
A stage-specific protein has been identified in gametocytes of Plasmodium falciparum. The protein is represented on two-dimensional electrophoresis by peptides of two apparent Mr of 27,000 and 25,000, each of which has at least four different isoelectric points between pH 6.0 and 5.0. The protein is designated Pfg 27/25 (P. falciparum gametocyte-specific antigen of 27 and 25 kDa). By indirect immunofluorescence with a monoclonal antibody 1H12 specific for Pfg 27/25, this protein is present in gametocytes within 30 to 40 hr after invasion of a red blood cell by a merozoite and is present throughout subsequent maturation of the gametocyte; Pfg 27/25 is not detectable on the surface of extracellular gametes by immunofluorescence with Mab 1H12. Pfg 27/25 is absent from asexual stages of P. falciparum at any stage in their development. Pfg 27/25 is an abundant protein in gametocytes and represents between 5 and 10% of total protein of these stages. Pfg 27/25 is also a major immunogen in man during P. falciparum infection. Antibodies to this protein were readily detected in human sera from an area of holoendemic P. falciparum and also from an individual following a primary attack of P. falciparum.  相似文献   
944.

Background  

Nitric oxide and prostaglandin E2 (PGE2play pivotal roles in both the pathogenesis of osteoarthritis and catabolic processes in articular cartilage. These mediators are influenced by both IL-1β and mechanical loading, and involve alterations in the inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX)-2 enzymes. To identify the specific interactions that are activated by both types of stimuli, we examined the effects of dynamic compression on levels of expression of iNOS and COX-2 and involvement of the p38 mitogen-activated protein kinase (MAPK) pathway.  相似文献   
945.
The uptake of purines and pyrimidines by adults of Schistosoma mansoni was studied. Cytosine, thymine, and uracil entered the worms entirely by diffusion. Adenine, guanine, hypoxanthine, and the nucleosides adenosine and uridine were absorbed in part by mediated systems. The results of inhibitor studies suggest the presence of 5 distinct transport sites for these latter compounds. The interaction of adenosine monophosphate with these sites was also studied.  相似文献   
946.
在2017年6-7月对藏东南地区蝶类资源进行调查时,于墨脱县采集到了2枚芒蛱蝶Euripusnyctelius(鳞翅目:蛱蝶科)标本,经鉴定为西藏新纪种,同时也是首次在西藏发现芒蛱蝶属;于察隅县采集到1枚黄缘蛱蝶Nymphalisantiopa(鳞翅目:蛱蝶科),兹此列举诸多川藏地区黄缘蛱蝶的历史采集记录;并结合西藏处于古北区和东洋区生物交界带的地理位置,对在西藏发现两种蝴蝶的特殊意义进行了简要讨论。  相似文献   
947.
This article describes a secondary analysis of the National Assessment of Educational Progress 2008 eighth-grade visual arts data (N = 3,912). These assessments occur under government mandate on a periodic schedule and data on the arts were collected in 1997 and again in 2008. The purpose of this study was to predict students' visual art response performance using students' home environment, personal characteristics, in-school curriculum, and art-related not-for-school (extracurricular) activities. Formative measurement models and structural paths were modeled in structural equation modeling (SEM) using Smart PLS. The initial SEM model included four latent constructs and one endogenous variable measuring students' performance. Both direct and indirect effects between latent constructs were modeled and assessed. Altogether, the four latent constructs explained 21.3% of the variance students' responding performance, out of which home environment construct had the strongest impact. School-related artistic activities in school do predict students' performance significantly but in lesser strength. Students' personal attributes and their art-related not-for-school activities predict students' performance to a substantially lesser degree. Implications of these findings will be discussed in terms of the data findings and larger issues of what these data represent as a means of following curriculum articulation with standards and the impact of art specialists in schools.  相似文献   
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949.
950.
Hominid fossil teeth are analyzed in terms of size and shape and contrasted with teeth from a modern population to determine boundaries that can be placed on a reconstruction of the hominid phylogeny. Teeth alone are considered as they are the only material preserved in large enough quantities to measure population variability accurately. Problems with the use of indices such as size and shape as species markers are discussed. Conclusions that are made about possible phylogenies are based on the analysis of size and shape.  相似文献   
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