Interactive effects of soil water deficit and air vapour pressure deficit on mesophyll conductance to CO2 in Vitis vinifera and Olea europaea.

The present work aims to study the interactive effect of drought stress and high vapour pressure deficit (VPD) on leaf gas exchange, and especially on mesophyll conductance to CO(2) (g(m)), in two woody species of great agronomical importance in the Mediterranean basin: Vitis vinifera L. cv. Tempranillo and Olea europaea L. cv. Manzanilla. Plants were grown in specially designed outdoor chambers with ambient and below ambient VPD, under both well-irrigated and drought conditions. g(m) was estimated by the variable J method from simultaneous measurements of gas exchange and fluorescence. In both species, the response to soil water deficit was larger in g(s) than in g(m), and more important than the response to VPD. Olea europaea was apparently more sensitive to VPD, so that plants growing in more humid chambers showed higher g(s) and g(m). In V. vinifera, in contrast, soil water deficit dominated the response of g(s) and g(m). Consequently, changes in g(m)/g(s) were more related to VPD in O. europaea and to soil water deficit in V. vinifera. Most of the limitations of photosynthesis were diffusional and especially due to stomatal closure. No biochemical limitation was detected. The results showed that structural parameters played an important role in determining g(m) during the acclimation process. Although the relationship between leaf mass per unit area (M(A)) with g(m) was scattered, it imposed a limitation to the maximum g(m) achievable, with higher values of M(A) in O. europaea at lower g(m) values. M(A) decreased under water stress in O. europaea but it increased in V. vinifera. This resulted in a negative relationship between M(A) and the CO(2) draw-down between substomatal cavities and chloroplasts in O. europaea, while being positive in V. vinifera.

Influencia de las creencias religiosas en las actitudes en el personal sanitario (P.S.) ante la muerte / Influence of religious beliefs on the attitudes of health professionals (H.P.) in the face of death

Fundamento: Las creencias religiosas son una variable psicosocial de gran importancia para una proporción considerable de la población, entre la que se encuentran los Profesionales Sanitarios y, por consiguiente, influye en las actitudes que estos tienen hacia los demás. Por ello, es deseable investigar dichas influencias, sobre todo en situaciones críticas de la vida, entre las que se incluye la muerte por su trascendencia a la hora de la atención al enfermo terminal. Objetivos y Metodología: Analizar las influencias de las creencias religiosas en las actitudes ante la muerte en el P.S. estableciendo su prevalencia y correlacionándolas con variables psicosociales y personalísticas, con otros aspectos religiosos, así como con la experiencia con moribundos; mediante técnicas psicométricas y un inventario de creencia religiosa, siguiendo un diseño observacional-transversal, sobre una muestra representativa de la población del P.S. de un Hospital Universitario. Resultados y Conclusiones: La mayoría del P.S. que componen la muestra resultan creyentes religiosos (con un nivel medio de práctica "moderado"). Las mujeres se muestran más religiosas que los hombres y los jóvenes resultan menos religiosos que las personas mayores. De los dos grupos extremos bien diferenciados que aparecen (creyentes practicantes y no creyentes, por un lado y creyentes no practicantes, tibios en su fe, agnósticos, etc., por otro) los que menos ansiedad ante la muerte manifiestan son los creyentes practicantes y no creyentes. El P.S., en general, presenta baja ansiedad (Estado y Rasgo) y baja ansiedad ante la muerte (AU)

Within-tree variation in transpiration in isolated evergreen oak trees: evidence in support of the pipe model theory.

Within-tree variation in sap flow density (SFD) was measured in two isolated evergreen oak (Quercus ilex L.) trees growing in an oak savannah (dehesa) in southwest Spain. Sap flow was estimated by the constant heating method. Three sensors were installed in the trunk of each tree in three orientations: northeast (NE), northwest (NW) and south (S). Sap flow density was monitored continuously from May 18 to September 27, 1993. Daily values of SFD ranged between 500 and 4500 mm3 mm-2 day-1. There were significant differences in SFD between orientations; SFD was higher in the NE and NW orientations than in the S orientation. These differences were noted on both a daily and seasonal time scale, and were less pronounced on cloudy days and at the end of the drought period, when SFD was relatively low. Our results support the idea that branches of trees can be viewed as a collection of small independent plants.

Cytostatic quinones. 3. Synthesis of benzotriazolequinones by a new oxidation with m-chloroperbenzoic acid. Biochemical studies.

Oxidation of N-1 and N-2 alkylbenzotriazoles with m-chloroperbenzoic acid afforded 1-alkylbenzotriazole 3-oxides and 2-alkylbenzotriazole-4,4-diones, respectively. The quinonic compounds inhibited the "in vitro" growth of both HeLa and KB cells, the synthesis of macromolecules (DNA, RNA, and proteins), and the uptake of glucose by Ehrlich carcinoma ascites cells. A possible mode of action is suggested.