Plants are considered as archetypes of the ramification phenomenon but numerous elementary processes occur in the elaboration of the shaping of each species. This paper aims to identify the part ascribed to different mechanisms in the morphogenesis of a Thallophyte, the red alga Antihamnion plumula.Agonistic-antagonistic models (Bernard-Weil, 1988) can be applied to this alga whose thallus includes two different kinds of whorls, pleuridian and cladomian. In each whorl the agonistic and antagonistic effects are expressed by the full development (S) of (...) the two branches and by their symmetry rate (R) respectively. Variations in S and R show the existence of particular pleuridian whorls having an intermediary dissymmetry and a rhythmic arrangement similarly to that of the cladomian whorls. A unilateral change of the system (removal of a lateral cladome) induces a transitory destabilisation mainly manifested by the stimulating ascendant flow throughout the thallus. (shrink)

The development of the typical cladomothallus of the red algae Antithaminion plumula (Ellis) Le Jolis [= Pterothamnion plumula (Ellis) Nägcli], (Rhodophyceae, Ceramiales) is simulated with the help of a formal language called L-systems. Two types of uniseriate filaments are distinguished: axial filaments of cladomes with indefinite growth and branching and pleuridia with definite growth and branching. The rythmical acropetal formation of secondary axes with basitonic arrangement contrasts with the intercalary basitonic formation of pleuridia, resulting in an acrotonic arrangement within an (...) axial segment. Five types of cells and two types of cell divisions intervene in the system. In addition, for the graphical representations, some morphological particularities of A. plumula are taken into account: the curvature of axial filaments, the extension of growth zones, variable cell generation times, and segment length variability along an axis. The incidence of these variables on the generated thallus form is emphasized, pointing to the singularities of A. plumula. (shrink)

Despite the availability of evidence-based treatment models for adolescent behavior problems, little is known about the effectiveness of these programs for adolescents with callous-unemotional traits. Defined by lack of empathy, lack of guilt, flattened affect and lack of caring, CU traits have been linked to long-term anti-social behavior and unfavorable treatment outcomes and might be negatively related to outcomes in evidence-based programs such as Functional Family Therapy. This study used a single-group pre-post evaluation design with a sample of 407 adolescents (...) receiving FFT to investigate whether outcomes in FFT are predicted by CU traits and to what extent reliable changes in CU traits can be observed. The results showed that although CU traits are related to increased problem severity at baseline, they predicted neither treatment dropout nor post-treatment externalizing behavior and family functioning. CU traits were related to diminished improvement ratings, in particular with respect to parental supervision. Reductions in CU traits were observed across the time of treatment, and these were most profound among adolescents with elevated levels of CU traits at baseline. Further research should investigate whether certain evidence-based treatment components are more suited for adolescents with CU, and if the addition of specific intervention elements for reducing CU-traits could further improve outcomes for this high-risk population. (shrink)