University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

Environmental and physiological regulation of transpiration in tropical forest gap species: the influence of boundary layer and hydraulic properties.

Abstract: Environmental and physiological regulation of transpiration were examined in several gap-colonizing shrub and tree species during two consecutive dry seasons in a moist, lowland tropical forest on Barro Colorado Island, Panama. Whole plant transpiration, stomatal and total vapor phase (stomatal + boundary layer) conductance, plant water potential and environmental variables were measured concurrently. This allowed control of transpiration (E) to be partitioned quantitatively between stomatal (gs) and boundary layer (gb) conductance and permitted the impact of invividual environmental and physiological variables on stomatal behavior and E to be assessed. Wind speed in treefall gap sites was often below the 0.25 m s−1 stalling speed of the anemometer used and was rarely above 0.5 m s−1, resulting in uniformly low gb (c. 200–300 mmol m−2 s−1) among all species studied regardless of leaf size. Stomatal conductance was typically equal to or somewhat greater than gb. This strongly decoupled E from control by stomata, so that in Miconia argentea a 10% change in gs when gs was near its mean value was predicted to yield only a 2.5% change in E. Porometric estimates of E, obtained as the product of gs and the leaf-bulk air vapor pressure difference (VPD) without taking gb into account, were up to 300% higher than actual E determined from sap flow measurements. Porometry was thus inadequate as a means of assessing the physiological consequences of stomatal behavior in different gap colonizing species. Stomatal responses to humidity strongly limited the increase in E with increasing evaporative demand. Stomata of all species studied appeared to respond to increasing evaporative demand in the same manner when the leaf surface was selected as the reference point for determination of external vapor pressure and when simultaneous variation of light and leaf-air VPD was taken into account. This result suggests that contrasting stomatal responses to similar leaf-bulk air VPD may be governed as much by the external boundary layer as by intrinsic physiological differences among species. Both E and gs initially increased sharply with increasing leaf area-specific total hydraulic conductance of the soil/root/leaf pathway (Gt), becoming asymptotic at higher values of Gt. For both E and gs a unique relationship appeared to describe the response of all species to variations in Gt. The relatively weak correlation observed between gs and midday leaf water potential suggested that stomatal adjustment to variations in water availability coordinated E with water transport efficiency rather than bulk leaf water status.

Decolonizing Psychological Science: Introduction to the Special Thematic Section

Abstract: Despite unprecedented access to information and diffusion of knowledge across the globe, the bulk of work in mainstream psychological science still reflects and promotes the interests of a privileged minority of people in affluent centers of the modern global order. Compared to other social science disciplines, there are few critical voices who reflect on the Euro-American colonial character of psychological science, particularly its relationship to ongoing processes of domination that facilitate growth for a privileged minority but undermine sustainability for the global majority. Moved by mounting concerns about ongoing forms of multiple oppression (including racialized violence, economic injustice, unsustainable over-development, and ecological damage), we proposed a special thematic section and issued a call for papers devoted to the topic of "decolonizing psychological science". In this introduction to the special section, we first discuss two perspectives—liberation psychology and cultural psychology—that have informed our approach to the topic. We then discuss manifestations of coloniality in psychological science and describe three approaches to decolonization—indigenization, accompaniment, and denaturalization—that emerge from contributions to the special section. We conclude with an invitation to readers to submit their own original contributions to an ongoing effort to create an online collection of digitally linked articles on the topic of decolonizing psychological science.