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1.
FBP和FCNN网络是模式识别中应用最为广泛的两种神经网络,本文将这两种网络应用于车型识别,分别建立了车型识别模型。利用混沌对初值的极端敏感依赖提出了FCNN网络算法,通过对车型图像数据库进行仿真实验,对比分析它们各自的识别率和泛化能力等性能指标,证明了FCNN网络算法的有效性。  相似文献   

2.
Summary In smooth endoplasmic membranes of rat splenic cells, glycosyl-transferase activities are located in various structures. These structures are separated by sucrose density gradient centrifugation. At the bottom are mannosyl- and N-acetyl-glucosaminyl-transferases; in the medium are mannosyl-and galactosyl-transferases; at the top are also mannosyl- and galactosyl-transferases, but no N-acetyl-glucosaminyl-transferase.  相似文献   

3.
首先介绍了农田渍害的表现特征;其次根据监测原理,将国内外农田溃害遥感监测的主要方法分为地表指示标志法、地下水位反演法和与非遥感方法相结合的综合分析法,并分别对各类方法的原理、技术、适用范围及优缺点进行分析,发现各种方法均能解决特定的农田渍害监测问题,同时也存在着缺陷和局限性;最后,进行了总结并指出了两种潜在的遥感监测方...  相似文献   

4.
M Baggiolini  B Dewald 《Experientia》1988,44(10):841-848
Simple testing models have been developed for the evaluation of chemical or biological compounds that modulate the activity of human phagocytes. Human neutrophils from buffy coats of donor blood are used. They are stimulated with receptor agonists, and the effects of test compounds on exocytosis of different enzymes, the generation of superoxide (respiratory burst), and cytotoxicity are quantified. All assays are performed in microtiter plates and the responses are evaluated by multi-well photometry or fluorimetry. The models are apt to detect compounds acting on phagocytes as agonists or antagonists, signal transduction activators or inhibitors and primers of agonist responses, and to assess cytotoxic effects.  相似文献   

5.
Summary Simple testing models have been developed for the evaluation of chemical or biological compounds that modulate the activity of human phagocytes. Human neutrophils from buffy coats of donor blood are used. They are stimulated with receptor agonists, and the effects of test compounds on exocytosis of different enzymes, the generation of superoxide (respiratory burst), and cytotoxicity are quantified. All assays are performed in microtiter plates and the responses are evaluated by multi-well photometry or fluorimetry. The models are apt to detect compounds acting on phagocytes as agonists or antagonists, signal transduction activators or inhibitors and primers of agonist responses, and to assess cytotoxic effects.  相似文献   

6.
In immuno-induced exocrine pancreatic carcinomas, which keep their exocrine secretory specificity through their different evolution stages [(1), (2)], normal B, A and D endocrine cells are still found, demonstrated by immunochemical techniques. They are localized in the islets of Langerhans. B and A cells are scattered in adenomatous pancreatic remains, and in the anaplasic carcinoma; D cells are found in the ductular and adenomatous remains. The three types of endocrine secretion granules are analyzed by electron microscopy at the early and late stages of carcinogenesis. The origin of the persisting endocrine cells and the nature of undifferentiated cells proliferating from the ductular epithelium are discussed.  相似文献   

7.
Summary Five topics concerning medical population genetics have been selected for discussion: in the field of population cytogenetics, the frequency of chromosomal aberrations and the roles of mutation and selection in the maintenance of balanced rearrangements are studied; the long term genetic effects of treatment and prevention of genetic diseases are reviewed; the relationships between malaria and the sickle-cell trait are discussed; some recent works concerning human DNA polymorphisms in the field of population, genetics are presented, and finally, some methods of genetic epidemiology are described.  相似文献   

8.
9.
This paper considers the forecast accuracy of a wide range of volatility models, with particular emphasis on the use of power transformations. Where one‐period‐ahead forecasts are considered, the power autoregressive models are ranked first by a range of error metrics. Over longer forecast horizons, however, generalized autoregressive conditional heteroscedasticity models are preferred. A value‐at‐risk‐based forecast assessment indicates that, while the forecast errors are independent, they are not independent and identically distributed, although this latter result is sensitive to the choice of forecast horizon. Our results are robust across a number of different asset markets. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

10.
This paper presents some procedures aimed at helping an applied time-series analyst in the use of power transformations. Two methods are proposed for selecting a variance-stabilizing transformation and another for bias-reduction of the forecast in the original scale. Since these methods are essentially model-independent, they can be employed with practically any type of time-series model. Some comparisons are made with other methods currently available and it is shown that those proposed here are either easier to apply or are more general, with a performance similar to or better than other competing procedures.  相似文献   

11.
M A Persinger 《Experientia》1987,43(1):92-104
Temporal and regional variations in psychological processes have been associated with three geological factors. They are geochemical profiles, geomagnetic variations, and tectonic stresses. In the geochemical domain, copper, aluminum, zinc, and lithium may influence the incidence of thought disorders such as schizophrenia and senile dementia. These common elements are found in many soils and ground water. Geomagnetic variations have been correlated with enhanced anxiety, sleep disturbances, altered moods, and greater incidences of psychiatric admissions. The effects are usually brief but pervasive. Transient and very local epidemics of bizarre and unusual behaviors are sociological phenomena that sometimes precede increases in earthquake activity within a region; they have been hypothesized to be associated with tectonic strain. Many of the contemporary correlations between geological factors and human behavior are also apparent within historical data. The effects of geophysical and geochemical factors upon human behavior are not artifactual, but they are complex and often not detected by the limited scope of most studies.  相似文献   

12.
In recent years a doctrine known as ontic structural realism (OSR) has achieved a degree of notoriety, but many people remain confused as to what exactly the doctrine amounts. In this paper three main variants of OSR are defined and discussed: (i) OSR1, which is the view that relations are ontologically primitive but objects and properties are not; (ii) OSR2, which is the view that objects and relations are ontologically primitive but properties are not; (iii) OSR3, which is the view that properties and relations are ontologically primitive but objects are not. Proponents of OSR claim that it is a “naturalistic” metaphysics, arguing that metaphysical views that take objects and/or properties as ontologically primitive are undermined by contemporary physics. In this paper it is argued that OSR1 and OSR2 are themselves undermined by contemporary physics. On the other hand, it is also argued that considerations about the objects of quantum mechanics and general relativity do seem to suggest that we should abandon some of our “common-sense” metaphysical intuitions, and that OSR3 is one of the metaphysical views that is compatible with what these theories seem to tell us about fundamental ontology.  相似文献   

13.
The features and intensities of electric and magnetic fields in the environment are described. Natural as well as technical constant and variable fields are considered in the light of their possible biological effects. The upper limits of the various fields are discussed. Results of laboratory measurements and also of epidemiological investigations are presented. The question is raised whether atmospheric small ions can cause a biological effect.  相似文献   

14.
The genetic study of 11 lymphocyte factors previously described in sheep was continued. 9 factors are the products of alleles at two closely linked loci OLA-A and B. The last two factors are the products of two genes at two distinct loci OL-X and OL-Z. Recombinations between the two closely linked loci are very rare (0.6%); but they are frequent between these two loci and OL-X (26%). The OL-Z locus seems to be independent of the two linked loci OLA-A and B. The allele frequencies at the four loci are given.  相似文献   

15.
依据地质动力区划方法,对鹤壁八矿进行Ⅰ~Ⅴ级活动断裂划分,确定了区域构造的特征。分析了煤层的顶板岩性和构造断裂特点,并在此基础上建立了构造应力计算模型。结合对矿区地应力测量和岩体应力状态分析,确定了岩体应力状态的分布规律。通过对结果的分析,认为区域构造应力场控制鹤壁八矿地应力的分布状态,从而决定煤与瓦斯突出呈区域性分布。确定了易发生煤与瓦斯突出的应力升高区的位置,为开采煤层时何时何地采取防突措施提供了科学依据。  相似文献   

16.
Life without oxygen: what can and what cannot?   总被引:1,自引:0,他引:1  
A J Zehnder  B H Svensson 《Experientia》1986,42(11-12):1197-1205
The basic principles involved in the biotransformation of organic carbon compounds in the absence of molecular oxygen (dioxygen) are presented in this paper. The role of various electron acceptors during the breakdown of organic compounds is discussed and the metabolic end-products expected are summarized. The different biochemical possibilities and strategies for the anaerobic degradation of organic matter and the metabolic response of some organisms to anaerobiosis are elucidated. Positive and negative effects of anaerobiosis on environmentally relevant processes and their influence on man and on animals are reviewed. Finally, some examples of the biotechnological application of anaerobic processes are presented.  相似文献   

17.
Summary Temporal and regional variations in psychological processes have been associated with three geological factors. They are geochemical profiles, geomagnetic variations, and tectonic stresses. In the geochemical domain, copper, aluminum, zinc, and lithium may influence the incidence of thought disorders such as schizophrenia and senile dementia. These common elements are found in many soils and ground water. Geomagnetic variations have been correlated with enhanced anxiety, sleep disturbances, altered moods, and greater incidences of psychiatric admissions. The effects are usually brief but pervasive. Transient and very local epidemics of bizarre and unusual behaviors are sociological phenomena that sometimes precede increases in earthquake activity within a region; they have been hypothesized to be associated with tectonic strain. Many of the contemporary correlations between geological factors and human behavior are also apparent within historical data. The effects of geophysical and geochemical factors upon human behavior are not artifactual, but they are complex and often not detected by the limited scope of most studies.  相似文献   

18.
This paper is concerned primarily with the evaluation and comparison of objective and subjective weather forecasts. Operational forecasts of three weather elements are considered: (1) probability forecasts of precipitation occurrence, (2) categorical (i.e. non-probabilistic) forecasts of maximum and minimum temperatures and (3) categorical forecasts of cloud amount. The objective forecasts are prepared by numerical-statistical procedures, whereas the subjective forecasts are based on the judgements of individual forecasters. In formulating the latter, the forecasters consult information from a variety of sources, including the objective forecasts themselves. The precipitation probability forecasts are found to be both reliable and skilful, and evaluation of the temperature/cloud amount forecasts reveals that they are quite accurate/skilful. Comparison of the objective and subjective forecasts of precipitation occurrence indicates that the latter are generally more skilful than the former for shorter lead times (e.g. 12–24 hours), whereas the two types of forecasts are of approximately equal skill for longer lead times (e.g. 36–48 hours). Similar results are obtained for the maximum and minimum temperature forecasts. Objective cloud amount forecasts are more skilful than subjective cloud amount forecasts for all lead times. Examination of trends in performance over the last decade reveals that both types of forecasts for all three elements increased in skill (or accuracy) over the period, with improvements in objective forecasts equalling or exceeding improvements in subjective forecasts. The role and impact of the objective forecasts in the subjective weather forecasting process are discussed in some detail. The need to conduct controlled experiments and other studies of this process, with particular reference to the assimilation of information from different sources, is emphasized. Important characteristics of the forecasting system in meteorology are identified, and they are used to describe similarities and differences between weather forecasting and forecasting in other fields. Acquisition of some of these characteristics may be beneficial to other forecasting systems.  相似文献   

19.
The espins are novel actin-bundling proteins that are produced in multiple isoforms from a single gene. They are present at high concentration in the parallel actin bundle of hair cell stereocilia and are the target of deafness mutations in mice and humans. Espins are also enriched in the microvilli of taste receptor cells, solitary chemoreceptor cells, vomeronasal sensory neurons and Merkel cells, suggesting that espins play important roles in the microvillar projections of vertebrate sensory cells. Espins are potent actin-bundling proteins that are not inhibited by Ca2+. In cells, they efficiently elongate parallel actin bundles and, thereby, help determine the steadystate length of microvilli and stereocilia. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells. Certain espin isoforms can also bind phosphatidylinositol 4,5-bisphosphate, profilins or SH3 proteins. These biological activities distinguish espins from other actin-bundling proteins and may make them well-suited to sensory cells.  相似文献   

20.
Bifurcation properties of two-dimensional bifurcation system are studied in this paper. Universal unfolding and transition sets of the bifurcation equations are obtained. The whole parametric plane is divided into several different persistent regions according to the type of motion, and the different qualitative bifurcation diagrams in different persistent regions are given. The bifurcation properties of the two-dimensional bifurcation system are compared with its reduced one-dimensional system. It is found...  相似文献   

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