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Ecdysterone acts differently according to the period of the moulting cycle when it is applied. In period C it induces apolysis, while at the beginning of apolysis it delays ecdysis. Experiments show that the exoskeleton cannot be rejected in the presence of ecdysterone. The possibility of stopping exuviation or ecdysis with ecdysterone seems to prove that this phenomenon is controlled by a particular factor called the factor of exuviation or the ecdysis factor. Ecdysterone would control only the release of this specific factor but would not prevent its action.  相似文献   

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Electrograms of the thoracic pulsatile organs and of the heart during emergence and expansion of the wings have been made. The mesotergal and metatergal organs function in a similar way: active periods are interrupted by short periods of rest, but the two organs contract with different but apparently independent rhythms. During emergence and expansion, the rate of contraction of the pulsatile organs increases twofold, and the resting periods disappear during the entire period of expansion of the wings. When the wings are removed or cut short, the activity of the pulsatile organs is inhibited.  相似文献   

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Conclusion En 1959, dans une note (2) à l'Académie des Sciences, nous écrivions, en conclusion d'un travail préliminaire sur l'étude immunoélectrophorétique desCandida: Si l'avenir apportait la démonstration de résultats similaires obtenus avec d'autres champignons que les levures du genreCandida, on disposerait en mycologie d'une méthode générale d'analyse des fractions antigéniques...; de plus, les connaissances acquises dans ce domaine auraient vraisemblablement d'heureuses répercussions pratiques sur les problèmes taxonomiques en suspens et sur le diagnostic sérologique des mycoses. Six ans plus tard, il nous semble que l'application de l'immunoélectrophorèse à la mycologie ait tenu ses promesses. Sans se substituer à d'autres techniques, ne fut-ce que parce que son objet est limité à l'étude des fractions antigéniques solubles ou à celle des anticorps précipitants, et parce que sa mise en oeuvre est souvent longue et délicate, elle complète heureusement ces techniques, apportant effectivement, dans bien des cas, un argument nouveau, analytique et élégant, à la taxonomie des champignons et ouvrant une voie nouvelle au diagnostic sérologique de certaines mycoses.(avec la collaboration technique deM. Brugge)Communication présentée à l' International Society for human and animal mycology, Third meeting. Edinburgh, July 31st-August 2nd, 1964.  相似文献   

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《L' Année biologique》1998,37(1):11-31
Analysis and synthesis have been widely used in systematics since, at least, the XIXth Century. Even now, the four major authors (Cronquist, Dahlgren, Takhtajan, Thorne) of angiosperm systems use “synthetic” to qualify their classifications. This word — synthetic or synthesis — has many different meanings that can create ambiguity. Among these meanings, is there one that can be justifiably used to define biological classifications? Although much more than the following applications can be found in the botanical literature, this paper will mainly deal with six meanings which are still in use in contemporary systematics. A synthetic classification has been understood as a classification built upward, from the lower to the higher categories. If we define synthesis as the operation that starts with elements and proceeds to a whole, then upward classification could be viewed as a synthesis in which the concept of hierarchy plays a primordial role, a role that is not initially a part of synthesis. Moreover, synthesis cannot replace all classificatory processes, and other criteria of taxa must be used in addition to synthesis Historically, synthesis has replaced analysis; the latter being employed by Linnaeus in his sexual system. Indeed, Linnaeus used a divisive method in producing his classification; and since division was seen as synonymous to analysis and recognized as a method that led to artificial taxa, leading French taxonomists Adanson, Lamarck and A.-L. de Jussieu among others, rejected analysis and viewed their classifications as synthetic, i.e., based on the natural method. Therefore, a system of value took place: natural was better than artificial, synthesis better than analysis. Reinforcing the importance of synthesis was the belief in a concept widely accepted at the end of the XVIIIth Century: that of continuity. Linking groups and forming a continuum was a procedure eminently synthetic. Such a procedure, known as “chaining”, produced series or sequences of taxa. Analysis was used solely to express the idea of dichotomous or analytical keys, a Lamarckian innovation that enabled taxonomists to identify plants. But whether classifications are built from lower to higher categories (a synthesis of taxa) or from higher to lower categories (an analysis of taxa), another simultaneous, concomitant movement is implied: with the latter, a synthesis of characters, with the former, an analysis of characters. Therefore, a synthetic classification is nevertheless an analytical classification.Basing groups on resemblance instead of difference, results in yet another application of synthesis. This application is probably due to the analogy with “composition”. Already, a separation between resemblance and difference among characters is an analysis. More important, still, is that at a certain rank some characters are used to join whereas, at another rank, they separate. Thus, depending on ranks and taxa, characters are applied in a synthetic or analytical procedure. Here also, other criteria are needed to support group delimitation.In connection with the upward (synthetic) movement in classifying taxa, the use of a great number of characters was also considered to be synthesis. This has been a recurring theme in taxonomy over the last two centuries and was sometimes seen as the Gilmourian approach to classification. When would we be justified to talk about synthesis? After how many characters? In fact, it is not the number of characters that matters but how characters are handled. The use of many characters has been closely linked to the idea of natural groups and its joining with synthesis seems to derive from the association of “natural” and “synthetic”.Synthetic classifications equally imply the common idea that they must represent a résumé of information stemming from all biological fields or disciplines. If classifications portray evolution, as many systematists suggest, then it cannot be just a résumé. And one must first decide what classifications are about: a controversial subject among different schools of thought in taxonomy. This explains another meaning attached to synthesis. Biological classifications have been said to be a synthesis or résumé of two types of information: that of similarity and that of phylogeny. Anagenesis is sometimes viewed as incremental to classification and makes up for a third type of information. Even though taxonomists would (for once!) agree that a classification should be based on phenetic, cladogenetic and anagenetic data, such a classification cannot qualify as a synthesis since it is not a composition and does not meet the definition given above (an operation that starts with elements and goes on to a whole). It is impossible to represent these three types of data together in one classification scheme; they express three, sometimes irreducible, points of view. For such a classification, the word “eclectic” is preferable and closer to reality.The use of synthesis as one term of the dialectical movement has made hesitant steps in taxonomy. Indeed, the two opposed theses that evolve into the synthesis are hardly met in classification and the “dialectical” synthesis promulgated by a few taxonomists can be referred back to synthesis as a résumé.Is classification synthetic because it appears to be based on inductive procedures, as it is sometimes implied by different authors who link deduction and analysis (stemming from downward classification)? In logic, synthesis is sometimes (and questionably so) associated with deduction. Moreover, synthesis cannot follow from induction which deals, for example, with the universality of characters. In that sense, there is no composition and so no synthesis. Thus, although induction has been part of classification, it is not a synthetic method.Apart from the ambiguity originating from the multiple meanings of the word “synthesis” in the context of taxonomy, synthetic classifications do not fully express all the complexity and procedures that lead to it. Actually, a classification is as much a synthesis as an analysis. Both methods are complementary, and should not be opposed as is sometimes the case. This opposition was implicit in the debate between Linneans and Jussieans, surrounding the development of the natural method. If one wants to use “synthetic”, then one should be explicit about its meaning. Taxonomists should also be aware of the incompleteness of synthesis in constructing a classification and should be careful not to create a system of value based upon philosophical ground. They should always prefer a complementary mode of thinking when feasible, instead of an “either-or” approach.  相似文献   

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Daniel Pajaud 《Geobios》1976,9(4):481-502
A benthic taphocoenose from the Pliocene I of Aguilas (provinces of Murcia-Almeria, Southern Spain) conseals four Cirripedia (family of BalanidaeLeach): Balanus (Balanus) perforatus angustusGmelin, B. (B.) amphitriteDarwin, B. (Megabalanus) tintinnabulum tintinnabulumLinné and Creusia (Withersia) phryxaPajaud.The study of the last one is especially interestingfrom an ecological point of view. Indeed, all species, well-known in the Creusia-Pyrgoma group are more or less dependent on Anthozoa since Miocene, the cuplike basis of their shell buried on corallites. But not corallites were gathered in the deposits of Aguilas and the morphology of Creusia phryxa leads us to believe a fixation of the shell on a flaccid substratum. From which we may suppose that the host of this Cirriped was perhaps an Actiniaria.  相似文献   

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The presence of intracellular osidases, nitrite and nitrate reductases, vitamin requirements and GC content in the DNA, have been investigated for in 18 species of Pichia.According to their typical characters and their biocaracters, a pattern is suggested for the integration of these new species into the formerly existing groups of the genus Pichia. A new way of classifying the species of the genus Pichia is proposed.  相似文献   

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13C NMR spectra of some tertiary and quaternary indole alkaloids are recorded and the signals assigned. Graphic interpretation of off-resonance spectra and substituent shielding effects together with the effect of Nb-methylation are utilized in the spectral interpretation.  相似文献   

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《Geobios》1986,19(3):327-333
This paper follows up on one published in Geobios1984, on the estimation of the velocity of trackmakers represented by fossil trackways.A simplification of the previously given formulaewill make it easier to calculate estimations of the lengths of «apparent limb, period and velocity of a walking animal. Observations show that the «walking angle decreases with the size of animals (in the case of a slow walk), the diminution being due to the exponential rising of the moment of inertia, a mathematical relation is proposed that links the «walking angle to the length of the radius of gyration i.e. the length of the «apparent limb. This relationship agrees with some datas from ichnology and with observations of living animals. With this equation and others presented here a table has been worked out which gives the estimates of «apparent limb, «walking angle, in terms of stride, estimates comprised in an interval of likelihood given by the coherent different values of the «walking angle. Velocity come from the pendular period. Interpolations from this table permit its utilization so for the values of the stride length distinct that presented.  相似文献   

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The question of the age of «Hauts de Meuse coral rag is studied again using new faunas of brachiopods and ammonites collected above, below and inside the coral rag. Ammonites fauna of the well known «Calcaires de Creuë is revised. Results obtained agree closely.The «Hauts de Meuse coral rag grew up during Middle Oxfordian time; and extend part of the Plicatilis zone (Antecedens Subzone) and the whole Transversarium Zone up to the basis of the Bifurcatus Zone, for the first time identified in Lorraine. So it span a short depositional time, about 1 MY, with a high deposition rate, the thickness of the coral rag being more than 100 meters, reaching 150 meters in Saint-Mihiel area. Towards SE, on the other side of the Marne Gap, the sudden change into basinal facies go with a reducing of thickness and deposition rate.Upper Oxfordian deposits show a relative uniformity of facies and thickness. At the top of Middle Oxfordian limestones, the age of the discontinuity and the Sequanian renewal of deposition is basal Bifurcatus Zone. Erosional renewal and terrigeneous deposits are a wide spread event by the beginning of Upper Oxfordian.In the paleontological part, species upon which are based new ages and interpretations are only figured, except the species new or with new paleontological data, which are described. Type specimen of Perisphinctes mosensisBayle, from the «Calcaires de Creuë, is described and photographically figured for the first time.  相似文献   

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