Les changements climatiques à la croisée des discours: Repenser le concept d’adaptation

The concepts migrate, so does the concept of adaptation. Between biology, discipline of origin and adaptation to climate change, we place ourselves in the second, particularly in the use of the concept as well as its perception. In fact, we seek to bring new elements of disambiguation by identifying pragmatic and enunciative semes relevant to the situation in which this concept was born. We designate by situation, a speech which is none other than "the utterance considered in its interactive dimension, its power of action on others, its inscription in a situation of enunciation (an enunciator, an allocution, a moment, a specific place) "(Maingueneau, 1991: 15), a discourse stemming from the dynamics governing the international discourse on climate change supported by the IPCC. The established meaning is situational, contextual and interdiscursive. Keywords: Adaptation, climate change, discursive semanticsLes concepts migrent, le concept d’adaptation aussi. Entre biologie, discipline d’origine et adaptation aux changements climatiques, nous nous plaçons dans la deuxième notamment dans l’usage du concept ainsi que sa perception. Nous cherchons en fait à apporter de nouveaux éléments de désambiguïsation en repérant des sèmes pragmatiques et énonciatifs relevant de la situation dans laquelle vient de naître ce concept. Nous désignons par situation, un discours qui n’est autre que « l’énoncé considéré dans sa dimension interactive, son pouvoir d’action sur autrui, son inscription dans une situation d’énonciation (un sujet énonciateur, un allocutaire, un moment, un lieu déterminé) » (Maingueneau, 1991 :15), un discours issu de la dynamique régissant le discours international sur les changements climatiques pris en charge par le GIEC. Le sens établi est d’ordre situationnel, contextuel et interdiscursif. Mots-Clés: Adaptation, changement climatique, sémantique discursiv

Comparison of flag leaf and ear photosynthesis with biomass and grain yield of durum wheat under various water conditions and genotypes

Photosynthetic activity of cereals has traditionally been studied using leaves, thus neglecting the role of other organs such as ears. Here, we studied the effects of water status and genotypes on the photosynthetic activity of the flag leaf blade and the ear of durum wheat. The various parameters related to the photosynthetic activity were analysed in relation to the total above-ground plant biomass and grain yield at maturity. Four local varieties plus two cultivars adapted to the semiarid areas of South Morocco were grown in pots in a greenhouse. Five different water treatments were maintained from the beginning of stem elongation to maturity, when shoot biomass and grain yield were recorded. The net photosynthesis (A), stomatal conductance (gs) and transpiration (T) of the ear and the flag leaf were measured at anthesis. In both organs these factors decreased significantly with water deficit, whereas the A/T and A/gs ratios increased. The genotype effect was also significant for all traits studied. Whole-organ photosynthesis was much higher in the ear than in the flag leaf in well-watered conditions. As water stress developed, photosynthesis decreased less in the ear than in the flag leaf. Whole-ear photosynthesis correlated better than flag leaf photosynthesis with biomass and yield. Nevertheless, the relationships of the whole flag leaf with biomass and yield improved as the water stress became more severe, suggesting a progressive shift of yield from sink to source limitation. For all water regimes the ratios A/gs and A/T of the ear also showed a higher (negative) correlation with both biomass and yield than those of the flag leaf. The results indicate that the ear has a greater photosynthetic role than the flag leaf in determining grain yield, not only in drought but also in the absence of stress

Acquired Immunodeficiency Syndrome Revealed by Oral Kaposi’s Sarcoma

Kaposi’s sarcoma is the malignant proliferation of the endothelial cell vessels. It is a systemic, malignant and multifactor disease. It usually presents initially as violaceous cutaneous lesions. Outside of a known context of an immune deficiency, an isolated oral lesions may not think to Kaposi’s sarcoma. Hence the interest of the histological and immunohistochemical study. This paper reviews one such case of Kaposi’s sarcoma in a 42-year-old woman who present an isolated pigmented lesions of the tongue, related to Kaposi’s sarcoma, without cutaneous or visceral involvement, and which led to the discovery of acquired immunodeficiency syndrome (HIV). The stabilization was obtained with antiretroviral triple therapy.</p

Comparison of flag leaf and ear photosynthesis with biomass and grain yield of durum wheat under various water conditions and genotypes

Photosynthetic activity of cereals has traditionally been studied using leaves, thus neglecting the role of other organs such as ears. Here, we studied the effects of water status and genotypes on the photosynthetic activity of the flag leaf blade and the ear of durum wheat. The various parameters related to the photosynthetic activity were analysed in relation to the total above-ground plant biomass and grain yield at maturity. Four local varieties plus two cultivars adapted to the semiarid areas of South Morocco were grown in pots in a greenhouse. Five different water treatments were maintained from the beginning of stem elongation to maturity, when shoot biomass and grain yield were recorded. The net photosynthesis (A), stomatal conductance (gs) and transpiration (T) of the ear and the flag leaf were measured at anthesis. In both organs these factors decreased significantly with water deficit, whereas the A/T and A/gs ratios increased. The genotype effect was also significant for all traits studied. Whole-organ photosynthesis was much higher in the ear than in the flag leaf in well-watered conditions. As water stress developed, photosynthesis decreased less in the ear than in the flag leaf. Whole-ear photosynthesis correlated better than flag leaf photosynthesis with biomass and yield. Nevertheless, the relationships of the whole flag leaf with biomass and yield improved as the water stress became more severe, suggesting a progressive shift of yield from sink to source limitation. For all water regimes the ratios A/gs and A/T of the ear also showed a higher (negative) correlation with both biomass and yield than those of the flag leaf. The results indicate that the ear has a greater photosynthetic role than the flag leaf in determining grain yield, not only in drought but also in the absence of stress