Propuesta de intervención en formación en valores para docentes. Centro educativo Ker Liber primaria

Trabajo que presenta la propuesta de intervención de formación en valores para los docentes del centro educativo Ker Liber. La propuesta se planteó desde la gestión participativa, que implicó abrir espacios de reflexión, análisis y diálogo que permitieron su desarrollo. La intervención presenta los elementos de reflexión, diálogo y toma de decisiones como transversales para que los docentes trabajen en el aula de manera intencionada y cotidiana y con ello se promueva la formación en valores, principalmente la libertad con responsabilidad. Se construyó una propuesta para ir más allá de la enseñanza memorística y rígida y promover la formación de valores desde la puesta en práctica que generen y trasciendan actitudes y acciones de libertad en responsabilidad

Factors affecting nectar sugar composition in chiropterophilic plants

AbstractMost pollinators prefer the sugars present in the nectar they consume, so it has been hypothesized that they have molded nectar trait evolution. However, nectar-feeding bats do not exhibit preferences for the sugars present in their diet. We analyzed the role that biochemical and ecological factors could play in shaping the nectar traits of chiropterophilic plants. We studied nectar traits and flower production in 49 plant species. We evaluated the relationship between nectar concentration and sugar composition using phylogenetically independent contrasts and if nectar traits were related to flower production using a Manova. We found that 42 species produced high hexoses nectars, and 7 species produced sucrose rich nectars. Phylogenetically independent contrasts showed that nectar concentration was negatively related to glucose content, positively related to fructose content, and was not related to sucrose content. A negative relationship was found from glucose and fructose contents to sucrose content, and glucose content was negatively related to fructose content. Finally, we did not found any relationship between nectar traits and the plants’ flowering strategies. We conclude that bat physiology and the relative low evolutionary time of the interaction between plants and bats may determine the lack of pattern in the nectar characteristics of chiropterophilic plants

Sucrose digestion capacity in birds shows convergent coevolution with nectar composition across continents

The major lineages of nectar-feeding birds (hummingbirds, sunbirds, honey-eaters, flowerpiercers, and lorikeets) are considered examples of convergentevolution. We compared sucrose digestion capacity and sucrase enzymatic activ-ity per unit intestinal surface area among 50 avian species from the New World,Africa, and Australia, including 20 nectarivores. With some exceptions, nectari-vores had smaller intestinal surfaces, higher sucrose hydrolysis capacity, andgreater sucrase activity per unit intestinal area. Convergence analysis showedhigh values for sucrose hydrolysis and sucrase activity per unit intestinal surfacearea in specialist nectarivores, matching the high proportion of sucrose in thenectar of the plants they pollinate. Plants pollinated by generalist nectar-feedingbirds in the Old and New Worlds secrete nectar in which glucose and fructose arethe dominant sugars. Matching intestinal enzyme activity in birds and nectarcomposition in flowers appears to be an example of convergent coevolution be-tween plants and pollinators on an intercontinental scale.Todd J. McWhorter, Jonathan A. Rader, Jorge E. Schondube, Susan W. Nicolson, Berry Pinshow, Patricia A. Fleming, Yocelyn T. Gutie, rrez-Guerrero, and Carlos Martı, nez del Ri

Flowerpiercers and hummingbirds: A comparative study of nectar feeding strategies in birds

Nectarivory has evolved independently eight times among birds. In the neotropics specialized nectarivory evolved in hummingbirds and flowerpiercers (genus Diglossa). Flowerpiercers are nectar-robbers of hummingbird-pollinated plants. Because flowerpiercers and hummingbirds are found in the same habitats feeding on the nectar of the same flowers, they provide us with a unique opportunity to understand the pressures that nectarivory imposes on animals. Flowerpiercers present beaks that have a long hook at the tip of their maxilla. The hook is used to hold tubular flowers in place while they stab them by projecting their lower mandible. Then, they insert their tongues in the puncture and extract nectar. I investigated the following questions: (1) What is the function of the flowerpiercer's hook, and which are the consequences of its evolution? (2) Are the digestive traits of flowerpiercers convergent with those of hummingbirds? (3) How do digestive traits affect sugar selection by nectar feeding birds? And (4) What are the effects of Diglossa baritula's physiology and behavior over its annual cycles? I found that nectarivorous flowerpiercers evolved from a frugivorous ancestor with a hookless beak. The evolution of a hooked bill allowed flowerpiercers to become efficient nectar-robers, but hindered their efficiency to feed on fruit. Using a phylogenetically informed approach, I found that the digestive traits of flowerpiercers and hummingbirds are not convergent. Unlike hummingbirds which have astounding intestinal sucrase activity levels, flowerpiercers had low sucrase activity. Nectar intake in D. baritula seems to be limited by its ability to digest sucrose. I also found that sugar preferences in nectar-feeding birds are concentration-dependent. At lower concentrations birds preferred hexoses, whereas at higher concentrations they preferred sucrose. Although nectar composition and concentration are often discussed as two different floral traits, they have a synergistic effect on the sugar preferences of nectar-feeding birds. D. baritula individuals exhibit biannual reproductive and molting cycles that are synchronized with flower and fruit abundance in the mountains of Mexico. The ability to rob nectar appears to have molded the evolution of the most important morphological, physiological and behavioral traits of D. baritula

On the Appropriateness of Performance-Based Compensation for Supervisory Board Members - An Agency Theoretic Approach

Central European countries such as Austria, Germany and the Netherlands require public firms to set up two separate boards: a management board (MB) that manages the firm and a supervisory board (SB) that controls the management. As part of the recent debate on corporate governance, the expansion of performance-based compensation to include members of the SB has been heavily discussed. In this paper we use a two-stage principal-agent model to investigate incentive effects arising from such contracting. The SB is responsible for contracting with the MB and for monitoring it. We allow for two types of performance measures to be available, a possibly biased financial report provided by the MB and the market price of the firm. We obtain the following results: both performance measures are beneficial and equally suitable for contracting with the MB. In contrast, the MB's report is never part of the optimal SB contract. Using the market price as a performance measure for the SB in some settings turns out to be beneficial as compared to a purely fixed compensation but not in others.