Floral odors and the interaction between pollinating Ceratopogonid midges and Cacao

Most plant species depend upon insect pollination services, including many cash and subsistence crops. Plants compete to attract those insects using visual cues and floral odor which pollinators associate with a reward. The cacao tree, Theobroma cacao, has a highly specialized floral morphology permitting pollination primarily by Ceratopogonid midges. However, these insects do not depend upon cacao flowers for their life cycle, and can use other sugar sources. To understand how floral cues mediate pollination in cacao we developed a method for rearing Ceratopogonidae through several complete lifecycles to provide material for bioassays. We carried out collection and analysis of cacao floral volatiles, and identified a bouquet made up exclusively of saturated and unsaturated, straight-chain hydrocarbons, which is unusual among floral odors. The most abundant components were tridecane, pentadecane, (Z)-7-pentadecene and (Z)-8-heptadecene with a heptadecadiene and heptadecatriene as minor components. We presented adult midges, Forcipomyia sp. (subgen. Forcipomyia), Culicoides paraensis and Dasyhelea borgmeieri, with natural and synthetic cacao flower odors in choice assays. Midges showed weak attraction to the complete natural floral odor in the assay, with no significant evidence of interspecific differences. This suggests that cacao floral volatiles play a role in pollinator behavior. Midges were not attracted to a synthetic blend of the above four major components of cacao flower odor, indicating that a more complete blend is required for attraction. Our findings indicate that cacao pollination is likely facilitated by the volatile blend released by flowers, and that the system involves a generalized odor response common to different species of Ceratopogonidae

School choice and information / School choice and information* Elección de escuelas e información

* We thank Gregory Elacqua, Andre Portela, Michael Handford, Carolina Leme, and the participants on the Worshop on School Choice, Competition, and Results for their comments and suggestions; to Fondecyt (project 1095176) and CEPPE, project CIE01-Conicyt for financial support; MINEDUC for the use of their data bases; and the companies Mapcity and DICTUC, for allowing us to use their data bases and maps that helped with the process of georeferencing schools and homes. The usual disclaimer applies.

Compensación Inflacionaria en Chile

Este documento provee un marco analítico simple para descomponer la compensación inflacionaria (ci). Las estimaciones sugieren que las compensaciones a uno y dos años se encuentran fuertemente ligadas a las expectativas de inflación, con valores recientes que no son necesariamente incoherentes con el cumplimiento de la meta de inflación. En el caso de la compensación de la inflación anual un año adelante (ci 1-1), los valores observados en marzo del 2008 requieren premios (liquidez, por ejemplo) en el orden de 100 pb para ser coherentes con una inflación esperada de 3% en un plazo de dos años. Aunque las compensaciones de más largo plazo son elevadas (ci 5-5), la brecha entre la ci 5-5 y la meta de inflación es relativamente baja cuando se la compara con la de otros países

Agudeza visual baja según residir en una ciudad rural del norte del Perú: estudio de casos y controles

Introduction In Peru, there are few studies which show that they might be a difference between school children in rural areas and the ones from non-rural areas, this is necessary because it has been shown that the place of residence is an influential exogenous factor in the development of low visual acuity. Likewise, the influence of environment on the development of visual errors and low visual acuity has been demonstrated. Methodology Case-control study between child population of an urban and a rural area (Piura and Joras); prior informed consent of their parents. The primary variable was the visual acuity, qualified with the principles of Snellen (sensitivity 85%, specificity 96%) 20/0 was considered as optimal and normal visual acuity was considered to 20/25. Values below were low visual acuity. Results 1,094 were surveyed. 50.0% (488) were female, and the median age was 9 years (interquartile range: 7-10 years). 22.6% (221) of the children had low visual acuity. In bivariate analysis, the age of children (p = .001), the degree coursing (p <.001) and city of residence (p = .005) were associated with low visual acuity of children. The multivariate analysis found that non-rural children had 1.55 (95% CI: 1.14 to 2.11, p-value = .005) more chances of having low visual acuity, adjusted for sex, age and degree academic growth of children. Conclusions It is concluded that children living non-rural residences have more low visual acuity in the northern Peru.Revisión por pare

Factors associated with the regular use of sources of information by medical students from four cities of Peru

Objetives. To determine the factors associated with regular use of sources of information by medical students in four cities in Peru. Materials and methods. In this cross-sectional study, medical students were surveyed in four cities of Peru, gathering information on the use of 14 sources of information and other educational and computer variables. Frequent use of the information source was defined if the respondent reported that they access an information source at least once a week. P values were obtained by generalized linear models adjusted for each respondent site. Results. 2,300 students were surveyed. The median age was 21 years and 53% were women. Having received training in the use of sources increased the use in twelve of the consulted bases, not in SciELO (p=0.053) or in the university library (p=0.509).When adjusting for owning a laptop/netbook, these associations remained. After also adjusting for owning a smartphone the association was lost with the BVS Peru database (p=0.067). The association was also lost after making the final adjustment, if the respondent had carried out any research activities. Conclusions. The frequent use of sources of information is associated with having received training, conducting research and use of information technologies and communication. This should be taken into account in training programs and continuous improvement in undergraduate [email protected]. Determinar los factores asociados al uso regular de fuentes de información en estudiantes de Medicina de cuatro ciudades de Perú. Materiales y métodos. Estudio transversal analítico, se encuestó a estudiantes de Medicina de cuatro ciudades del Perú, recopilando información del uso de 14 fuentes de información y otras variables educativas e informáticas. Se definió uso frecuente de la fuente de información si accedía a ella mínimo una vez a la semana. Se obtuvieron los valores p mediante modelos lineales generalizados ajustando por la sede de cada encuestado. Resultados. Se encuestaron 2300 estudiantes con una mediana de edad de 21 años, el 53% fueron mujeres. El recibir una capacitación para el uso de las fuentes incrementó el uso en doce de las bases consultadas, no en SciELO (p=0,053) ni en la biblioteca universitaria (p=0,509). Cuando se añadió el ajuste por poseer una laptop/netbook se mantuvieron dichas asociaciones. Al ajustar también por poseer un smartphone se perdió la asociación con la base BVS Perú (p=0,067), lo mismo ocurrió al hacer el último ajuste, si había realizado alguna actividad de investigación. Conclusiones. El uso frecuente de las fuentes de la información está asociado con haber recibido capacitación, realizar investigación y el uso de las tecnologías de la información y comunicación. Esto debe ser tomado en cuenta en programas de capacitación y mejora continua en el pre y posgrado