期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
非达尔文革命"与"进步"的观念 被引量:1
1
作者 杨海燕 《自然辩证法研究》 CSSCI 北大核心 2003年第4期55-59,85,共6页
通过"非达尔文革命"的概念,鲍勒对"达尔文革命"的正统形象提出了质疑。鲍勒认为:达尔文主义不是19世纪进化论的主题,现代"综合理论"的产生相对独立于达尔文所提出的自然选择学说。因此进化论的历史不等... 通过"非达尔文革命"的概念,鲍勒对"达尔文革命"的正统形象提出了质疑。鲍勒认为:达尔文主义不是19世纪进化论的主题,现代"综合理论"的产生相对独立于达尔文所提出的自然选择学说。因此进化论的历史不等于达尔文主义的历史。鲍勒对进化论历史的重建表明,以"发育"模型为基础的进化论在19世纪占据统治地位,"进步"的观念是这种"非达尔文"进化论发展的线索,《物种起源》的出版并没有阻断这个发展过程。由此鲍勒重现了"进步"的观念在19世纪的连续性。对"进步"观念和进化思想之间关系的考察,不仅对于重建进化论发展的历史来说是不可或缺的,而且也是理解我们这个现代世界的必由之路。 展开更多
关键词 非达尔文革命 自然选择学说 “发育”模型 “进步”观念 进化论
下载PDF
Study on Growth and Development Rules and Growth Curve Fitting of Minghua Black Minks
2
作者 荣敏 涂剑锋 +3 位作者 张志明 王淑茗 高峰 邢秀梅 《Agricultural Science & Technology》 CAS 2017年第2期285-286,302,共3页
Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very w... Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very well by Logistic model and Gompertz model (the degree of fitting FF≥0.99), but Gompertz model was better at fitting and predicting their weight. 展开更多
关键词 Minghua black minks Growth curve Non-lineared models Development rules FITTING
下载PDF
Studies on Molecular Mechanism of Human Early Cardiogenesis Using the Drosophila as a Model System 被引量:1
3
作者 吴秀山 《Developmental and Reproductive Biology》 2002年第1期64-74,共11页
Recently,some of the genetic mechanisms of heart specification have been elucidated in Drosophila .However,genes involved in early cardiogenesis of human remain to be identified.Since the pathways that regulate ear... Recently,some of the genetic mechanisms of heart specification have been elucidated in Drosophila .However,genes involved in early cardiogenesis of human remain to be identified.Since the pathways that regulate early cardiac fate determination are conserved between Drosophila and vertebrates,flies can be used as a model test system to explore the genetic basis of cardiogenesis in human.In this project,about 3000 reccieve lethal gene lines were produced by P or EMS mutagenesis.With staining of antibodies against heart precussor cells of Drosophila ,about 200 lines were observed to show heart phenotype.In pilot studies of their function with RNAi technique,the RNAi phenotypes of several genes tested were observed,which were very similar to that of their mutants,showing heart tube defects or no heart precursors formation.Taking advantage of the advanced genetic information available in the Drosophila and human systems,we have identified about 50 human transcripts homologous to the Drosophila heart related gene candidates.Northern blot analysis for some of the human candidates showed that several genes were expressed in both adult and early embryonic tissues,which may help in the evaluation of candidate genes for human cardiogenesis.Our further experiments with transgenic flies generated with wild type and mutant forms of these candidate genes to examine for defects in cardiogenesis or cardiac function are under way.The candidate genes producing cardiac specific defects suggestive of similarities to the heart disease syndromes can then be pursued further as likely disease gene candidates.Such an approach is likely to provide a dramatic reduction of possible candidate genes,or to screen and identify mutations that may generate the disease in human. 展开更多
关键词 molecular mechanism human early cardiogenesis Drosophila model system
下载PDF
An improved hypoplastic constitutive model of rockfill considering effect of stress path 被引量:4
4
作者 相彪 张宗亮 迟世春 《Journal of Central South University》 SCIE EI CAS 2009年第6期1006-1013,共8页
An incrementally nonlinear hypoplastic constitutive model was introduced, which was developed without recourse to the concepts in elastoplasticity theory such as yield surface, plastic potential and the decomposition ... An incrementally nonlinear hypoplastic constitutive model was introduced, which was developed without recourse to the concepts in elastoplasticity theory such as yield surface, plastic potential and the decomposition of the deformation into elastic and plastic parts. Triaxial drained tests on rockfill were conducted on a large scale triaxial apparatus under two types of stress paths, which were the stress paths of constant stress ratio and the complex stress paths with transitional features. Motivated by the effect of stress path, the Gudehus-Bauer hypoplastic model was improved by considering the parameter variations with different ratios of stress increment. Fitting parameter a presents a piecewise linear relationship with cosine of the slope angle θ determined by instantaneous stress path. The improved hypoplastic model can present peak stress increasing and volumetric strain changing from dilatancy to contractancy with the increase of transitional confining pressure σ3t and the decrease of slope angle θ of stress path. Compared with the test data, it is shown that the model is capable of fully considering the effect of stress path on rockfill. 展开更多
关键词 HYPOPLASTICITY constitutive model stress path triaxial drained test ROCKFILL
下载PDF
Feeding ecology of hairtail Trichiurus margarites and largehead hairtail Trichiurus lepturus in the Beibu Gulf, the South China Sea 被引量:2
5
作者 颜云榕 侯刚 +2 位作者 陈骏岚 卢伙胜 金显仕 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第1期174-183,共10页
We evaluated the feeding ecology of largehead hairtail (Trichiurus lepturus) and hairtail (T. margarites). We collected specimens from fishing ports in the Beibu Gulf (Gulf of Tonkin) from October 2008 to September 20... We evaluated the feeding ecology of largehead hairtail (Trichiurus lepturus) and hairtail (T. margarites). We collected specimens from fishing ports in the Beibu Gulf (Gulf of Tonkin) from October 2008 to September 2009 and analyzed their gut contents. We collected 857 T. lepturus and 666 T. margarites samples. The number of stomachs examined in this study was sufficient to describe the monthly and ontogenetic diet shifts for the two species, as indicated by the trophic diversity curves. T. lepturus was a general omnivore, feeding primarily on Bregmaceros rarisquamosu, Decapterus maruadsi, and Acetes chinensis. Conversely, T. margarites preyed primarily on D. maruadsi, B. rarisquamosus, B. nectabanus, and A. chinensis. Both species exhibited distinct ontogenetic diet shifts. Although the two hairtail specie fed on similar sources in the same habitat, the diet overlap was relatively low. Our results suggest that hairtail play an important role in controlling small pelagic and benthic fish populations in the gulf. This trophic correlation shall be used for developing a marine ecosystem model for the Beibu Gulf. 展开更多
关键词 feeding ecology Trichiurus margarites Trichiurus lepturus ontogenetic diet shift the Beibu Gulf South China Sea
下载PDF
Morphological changes and allometric growth in hatcheryreared Chinese loach Paramisgurnus dabryanus(Dabry de Thiersant, 1872) 被引量:11
6
作者 张云龙 吴巧婉 +7 位作者 胡伟华 汪帆 邵韦涵 张诚明 赵忠波 何辉 樊启学 顾泽茂 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第4期757-762,共6页
The length-weight relationship and allometric growth patterns of hatchery-reared Chinese loach, Paramisgurnus dabryanus(Dabry de Thiersant, 1872), were determined from hatching to 60 days after hatching. A best power ... The length-weight relationship and allometric growth patterns of hatchery-reared Chinese loach, Paramisgurnus dabryanus(Dabry de Thiersant, 1872), were determined from hatching to 60 days after hatching. A best power model was estimated for the length-weight relationship during the early life stages. Positive allometric growth for the head segment, trunk length, tail length and eye diameter was also found in the early life stages, while body depth, tail depth, tail fi n length, pectoral fi n length and barbel length displayed a negative coeffi cient. During the subsequent early developmental stage, the growth coeffi cients showed a clear and common tendency towards isometry for all measured body ratios. The allometric growth changes in Chinese loach during the early stage are possibly the result of selective organogenesis directed towards survival priorities. 展开更多
关键词 Paramisgurnus dabryanus early life stages length-weight relationship allometric growth
下载PDF
A Holistic Model for the Development of Entrepreneurial Competencies of the Entrepreneur XXI: The Tree Model
7
作者 Jose Luis Soares Ferreira Cristina Maria Pinto Albuquerque 《Chinese Business Review》 2012年第3期309-321,共13页
In the present article it will be critically questioned the traditional entrepreneurship education approaches based on a narrow conception of competency, and their values. Assuming the perspective that to be an entrep... In the present article it will be critically questioned the traditional entrepreneurship education approaches based on a narrow conception of competency, and their values. Assuming the perspective that to be an entrepreneur is basically an attitude towards life and the world, there proposed holistic, constructivist and experiential processes and strategies for entrepreneurship education. The "entrepreneur XXI", must be able to undertake a social function of change, so, an economical and social development more human, ethical and intelligent. Under this assumption, the "Tree Model for the Development of Entrepreneurial Competencies", that will be discussed globally in the second part of this article, suggests a dynamic and experiential approach ofentrepreneurship education based on the qualification of people's behaviour, self-esteem, competencies and experiences; a profile of key behavioural and performance competencies (root), experimental pedagogical procedures (trunk) and real results within group projects (fruits). This model has been developed during the last decade (2001-2011), using a multidisciplinary research-action procedure, within business, education (at different teaching levels) and social project environments. 展开更多
关键词 entrepreneurship education COMPETENCY tree model entrepreneur XXI
下载PDF
Hypoplastic constitutive modelling of the wetting induced creep of rockfill materials 被引量:9
8
作者 FU ZhongZhi CHEN ShengShui LIU SiHong 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第7期2066-2082,共17页
Discrete element simulations of one-dimensional compression of breakable granular assemblies were performed to investigate the capability of the exponential compression equation suggested by Bauer.The relationship bet... Discrete element simulations of one-dimensional compression of breakable granular assemblies were performed to investigate the capability of the exponential compression equation suggested by Bauer.The relationship between the so-called solid hardness and the particle strength was studied so as to provide a physical background for the introduction of a time-dependent solid hardness.A hyperbolic flow rule,describing the relationship between the inclination of the strain path and the stress ratio during wetting,was proposed based on typical triaxial wetting experiments on two different rockfill materials.The flow rule was then extended and incorporated into the transformed stress based hypoplastic model to capture the direction of creep strains.Meanwhile,a new density factor was introduced to the extended model to take into account the dependence of the magnitude of creep strains on the packing density.The stiffness tensor given by the extended model was discussed and the flowchart for the integration of the constitutive equation was designed.The extended model was then embedded into a finite element program and used to simulate the triaxial compression and wetting experiments performed on the aforementioned rockfill materials.Good agreement between the model predictions and the measured results lends sufficient credibility to the extended model in reproducing the stress-stain behaviour under loading and the creep behaviour during wetting.The extended model and the finite element program were also used to investigate the deformation behaviour of an earth-rock dam at the end of construction and during first impounding.The familiar phenomena such as the wetting induced settlement of the upstream shell and the movement of the dam crest towards the upstream were successfully captured by the numerical model,which confirms the feasibility of applying the extended model to dam engineering in the future. 展开更多
关键词 rockfill materials wetting induced creep HYPOPLASTICITY constitutive model dam engineering
原文传递
A model of inter-cohort cannibalism and paedomorphosis in Arizona Tiger Salamanders, Ambystoma tigrinum nebulosum 被引量:1
9
作者 Maeve L. McCarthy Howard H. Whiteman 《International Journal of Biomathematics》 2016年第2期221-233,共13页
Cannibalism is widespread in size-structured populations. If cannibals and victims are in different life stages, dominant cohorts of cannibals can regulate recruitment. Arizona Tiger Salamanders, Ambystoma tigrinum ne... Cannibalism is widespread in size-structured populations. If cannibals and victims are in different life stages, dominant cohorts of cannibals can regulate recruitment. Arizona Tiger Salamanders, Ambystoma tigrinum nebulosum, exhibit facultative paedomorphosis in which salamander larvae either metamorphose into terrestrial adults or become sexually mature while still in their larval form. Although many salamanders exhibit cannibalism of larvae, the Arizona Tiger Salamander also exhibits cannibalism of young by the aquatic adults. We formulate a differential equations model of this system under the assumption that the terrestrial adults do not impact the system beyond their contribution to the birth of young larvae. We establish non-negativity, boundedness and persistence of the salamander population under certain assumptions. We consider the equilibrium states of the system in the presence or absence of a birth contribution from the terrestrial or metamorph adults. Constant per capita paedomorphosis leads to asymptotically stable equilibria. The per capita paedomorphosis rate of the larvae must be density dependent in order for periodic solutions to exist. Furthermore, the stage transition rate must be sufficiently decreasing in order to guarantee the existence of an unstable equilibrium. Periodic solutions are only possible in the presence of a unique non-trivial unstable equilibrium. Our results conform to previous theory on paedomorphosis which suggests general applicability of our results to similar systems. 展开更多
关键词 CANNIBALISM size-structured population facultative paedomorphosis population model equilibrium analysis.
原文传递
A MULTIYEAR LAGS INPUT-HOLDING-OUTPUT MODEL ON EDUCATION WITH EXCLUDING IDLE CAPITAL 被引量:1
10
作者 Xue FU Xikang CHEN 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2009年第2期159-170,共12页
This paper develops a multi-year lag Input-Holding-Output (I-H-O) Model on education with exclusion of the idle capital to address the reasonable education structure in support of a sustainable development strategy ... This paper develops a multi-year lag Input-Holding-Output (I-H-O) Model on education with exclusion of the idle capital to address the reasonable education structure in support of a sustainable development strategy in China. First, the model considers the multiyear lag of human capital because the lag time of human capital is even longer and more important than that of fixed capital. Second, it considers the idle capital resulting from the output decline in education, for example, student decrease in primary school. The new generalized Leonitief dynamic inverse is deduced to obtain a positive solution on education when output declines as well as expands. After compiling the 2000 I-H-O table on education, the authors adopt modifications-by-step method to treat nonlinear coefficients, and calculate education scale, the requirement of human 2020. It is found that structural imbalance of human development. capital, and education expenditure from 2005 to capital is a serious problem for Chinese economic 展开更多
关键词 Education human capital idle capital Input-Holding-Output model multi-year lag.
原文传递
The effects of evolutionary and environmental variance on estimates of phylogenetic diversity in temperate forest plots 被引量:1
11
作者 Yong Xu Jia-Jia Liu +3 位作者 Hai-Ning Li Juan Liu Kevin S.Burgess Xue-Jun Geb 《Journal of Plant Ecology》 SCIE CSCD 2021年第1期96-107,共12页
Aims Phylogenetic diversity metrics can discern the relative contributions of ecological and evolutionary processes associated with the assembly of plant communities.However,the magnitude of the potential variation as... Aims Phylogenetic diversity metrics can discern the relative contributions of ecological and evolutionary processes associated with the assembly of plant communities.However,the magnitude of the potential variation associated with phylogenetic methodologies,and its effect on estimates of phylogenetic diversity,remains poorly understood.Here,we assess how sources of variation associated with estimates of phylogenetic diversity can pote ntially affect our understanding of plant community structure for a series of temperate forest plots in China.Methods In total,20 forest plots,comprising of 274 woody species and 581 herbaceous species,were surveyed and sampled along an elevational gradient of 2800 m on Taibai Mountain,China.We used multi-model inference to search for the most parsimonious relationship between estimates of phylogenetic diversity and each of four predictors(i.e.type of phylogenetic reconstruction method,phylogenetic diversity metric,woody or herbaceous growth form and elevation),and their pairwise interactions.Important Findings There was nosignificant difference in patterns of phylogenetic diversity when using synthesis-based vs.molecular-based phylogenetic methods.Results showed that elevation,the type of phylogenetic diversity metric,growth form and their interactions,accounted for>44% of the variance in our estimates of phylogenetic diversity.In general,phylogenetic diversity decreased with increasing elevation;however,the trend was weaker for herbaceous plants than for woody plants.Moreover,the three phylogenetic diversity metrics showed consistent patterns(i.e.clustered)across the elevational gradient for woody plants.For herbaceous plants,the mean pairwise distanee showed a random distribution over the gradient.These results suggest that a better understanding of temperate forest comunity structure can be obtained when estimates of phylogenetic diversity include methodological and environmental sources of variation. 展开更多
关键词 community assembly ELEVATION growth form multi-model inference phylogenetic diversity phylogeny reconstruction Taibai Mountain
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部