Quantifying interactions between accommodation and vergence in a binocularly normal population

AbstractStimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (mean±SD age 21.0±1.9years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r2=0.96, p<0.001) and CA/C ratios (r2=0.40, p<0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI −0.06 to 0.24MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI −0.46 to 0.42D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement

Ribeirinho Food Regimes, Socioeconomic Inclusion and Unsustainable Development of the Amazonian Floodplain

En examinant les changements dans l'acquisition des aliments et les habitudes alimentaires, cet article explore de manière critique le développement durable de l'Amazonie. Le changement des habitudes alimentaires est un indicateur fort des changements dans les perceptions, les usages et les engagements avec la nature dans l'Amazonie, en fournissant un moyen utile d'examiner l'écart entre les mythes de la durabilité et la réalité de l'urbanisation rapide et l'évolution des moyens de subsistance dans l'Amazonie contemporaine. Nous soutenons qu'une écologie politique des régimes alimentaires dans la plaine d'inondation amazonienne brésilienne - en s'appuyant sur des approches et des idées anthropologiques et géographiques - offre un avantage privilégié pour éclairer les contradictions des trajectoires actuelles de développement et les disparités socio-environnementales qu'elles engendrent, contribuant potentiellement à l'articulation des politiques de développement durable et d'inclusion sociale plus efficaces.Through examining changes in food acquisition and alimentary habits, this paper critically explores Amazonian sustainable development. The changing of alimentary habits is a strong indicator of changes in perceptions, uses, and engagements with nature in the Amazon, providing a useful vehicle for examining the gap between the myths of sustainability and the reality of rapid urbanization and changing livelihoods in the contemporary Amazon. We argue that a political ecology of food regimes in the Brazilian Amazonian floodplain—drawing on anthropological and geographic approaches and insights—provides a privileged vantage from which to illuminate the contradictions of current development trajectories and the socioenvironmental disparities they engender, potentially contributing to the articulation of more effective sustainable development and social inclusion policies

Stimulation by a low-molecular-weight angiogenic factor of capillary endothelial cells in culture.

A low-mol.-wt compound isolated from rat Walker 256 carcinoma and found to induce neovascularization in vivo was tested on cultures of cow brain-derived endothelial cells (CBEC) growing on plastic and collagen substrates. This factor had a mitogenic effect on CBEC cultured on native collagen gels and for this reason has been called "endothelial-cell-stimulating angiogenesis factor" (ESAF). CBEC growing on plastic culture dishes or denatured collagen films were not stimulated by ESAF. The mitogenic effect of ESAF was equally apparent when added to cells already attached to the native collagen substrate or when the collagen substrate was pre-incubated with ESAF before plating the cells. A floating collagen gel pre-incubated with ESAF in cultures of CBEC growing on plastic dishes did not stimulate cell growth. Our data indicate that the substrate influences cell behaviour and that CBEC only respond to ESAF when growing on a native collagen substrate