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  1. Roger Buis (1997). Sur l'Interprétation de la Loi Logistique de Croissance: Une Re-Lecture de la Relation Entre Autocatalyse Et Croissance on the Interpretation of the Logistic Law of Growth: A New Reading of the Relationships Between Autocatalysis and Growth. Acta Biotheoretica 45 (3-4).
    The logistic function now constitutes the most widely used model for there presentation of growth kinetics of the continuous monotonous type in biological systems (populations, organisms, organs, ...). This ubiquity led to consider logistics from a phenomenological rather than mechanistic viewpoint. Whence the question : can logistics be given an interpretation, a signification which confers the rank of an "explicative" model to it? This Note presents some critical comments on the relationships between logistics and three types of biological systems : (...)
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  2. Roger Buis, Marie-Thérèse L'Hardy-Halos & Cécile Lambert (1996). Caracterisation de la Structure d'Un Processus de Croissance. Acta Biotheoretica 44 (3-4).
    The analysis of a growth kinetics y(t) is carried out using the generalized logistic model of Richards — Nelder. Two types of processes, termed mono- and multi-logistic, can be distinguished.In a mono-logistic process, the phenomenon is adequately described by only one logistic function. The growth kinetics is then characterized by the properties of each of phases G 1 to G 4, with boundaries defined by the singular points max, V max and min (Buis, 1991, 1993). The growth structure (temporal or (...)
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  3. Roger Buis, Henri Barthou, Christian Brière & Joëlle Gefflaut (1995). Leaf Dissymmetry and Vein Growth Field. Acta Biotheoretica 43 (1-2).
    The growth of the vein system of the leaf ofTropaeolum peltophorum was studied (i) at the vein level (analysis of the growth kinetics and of the growth field of the 7 primary veins) and (ii) at the limb level (comparison of the growth of the veins).The vein growth kinetics depend on the position of the vein on the leaf: there is a proximal/distal gradient and a bilateral gradient of the growth parameters (=variation of the temporal organization of the kinetics). The (...)
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  4. Roger Buis & Christian Brière (1995). Foreword. Acta Biotheoretica 43 (1-2).
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  5. Cécile Lambert, Roger Buis & Marie-Thérèse L'Hardy-Halos (1995). Le Phenomene d'Heteroblastie Chez Les Vegetaux: Comment L'Expliquer? Acta Biotheoretica 43 (1-2).
    Heteroblastic development is often observed in Cormophytae, but it can also be characterized in Thallophytae as shown by the detailed investigation of the development of the algaAntithamnion plumula (Ceramiaceae, Rhodophyta). In this species, heteroblasty concerns (i) dimensional variables (such as pleuridia length and lateral cladome first tagma length) and (ii) variables that characterize the cell growth kinetics (main axis cells). Apex curvature also varies during ontogenesis.The generality of the property in plants led to search for its origin: apical meristem own (...)
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  6. Roger Buis (1993). Growth Activity and Structure at Various Organization Levels in Plants. Acta Biotheoretica 41 (3).
    The growth activity of an organ (variable y) is defined simultaneously by the instantaneous absolute ratedy/dt and its variationd 2y/dt2. The use of these two descriptors allows a sigmoidal (i.e. continuous and non periodical, as observed for the logistic function) growth curve to be discretized into a series of 5 growth states or phases which are delimited by the following singular values: max, Vmax (=0), max, adult stage. The (V, ) plot, termedgrowth trajectory, visualizes, e.g. in the case of Richards-Nelder's (...)
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  7. Cécile Lambert, Roger Buis & Marie-Thérèse L'Hardy-Halos (1992). Kinetics of Pleuridial Growth in Antithamnion Plumula (Rhodophyceae). Acta Biotheoretica 40 (2-3).
    The filamentous and branched thallus of Antithamnion plumula is constitued of two different kinds of branches with apical growth: the cladomial axes with a continuous or indefinite growth, and the pleuridia with a limited growth. The size of the pleuridia depends on their position with respect to the lateral cladomial axes.The growth kinetics of 35 pleuridia were analysed using Nelder's generalized logistics. Each sigmoidal curve, which was divided into four growth stages from the instantaneous acceleration variations, was thus characterized by (...)
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  8. Roger Buis (1991). On the Generalization of the Logistic Law of Growth. Acta Biotheoretica 39 (3-4).
    This communication presents a discussion of some extensions of the formalism of Verhulst's simple logistics, which may constitute an autonomous growth model of a more general scope.For that purpose, the basis concept of growth diagram or trajectory is called upon, as it affords the graphic representation of the change in the growth variable y, using two relevant kinetic parameters: the instantaneous rate and the instantaneous acceleration. The two possible kinds of trajectories are in relation to the use of absolute (V (...)
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