Estudo fitoquímico de folhas de Solanum lycocarpum A. St.-Hil (Solanaceae) e sua aplicação na alelopatia

(Phytochemistry of Solanum lycocarpum A.St.–Hil (Solanaceae) leaves and their application in allelopathy). Solanum lycocarpum A.St.-Hil (Solanaceae) is a typical shrub in the Cerrado of central Brazil. The allelopathic activity of aqueous extracts of the leaves and fruits of this species has already been proven in previous studies. The goal of this work was to verify the allelopathic activity of different leaf extracts of S. lycocarpum on the germination and growth of four target species. The leaves were collected, dried, triturated and submitted to two distinct methods of extraction: 1- liquid--liquid (ethyl acetate and dichloromethane) from the aqueous extract and 2- with solvents of increasing polarities (hexane, dichloromethane, ethyl acetate, acetone, methanol and water) directly from the leaves. Each extraction was made with ultrasound equipment for one hour, filtered and evaporated. From these extracts, solutions of 800, 400 and 200 ppm were prepared, and water and Logran® were used as positive and negative controls, respectively. Each solution, as well as the controls, was dissolved in DMSO for the bioassays. The target species used were lettuce, watercress, tomato and onion. To each plate, 20 seeds were added and 1 mL of the tested solutions (with 4 repetitions). The plates were incubated at 25 oC without light, and the shoots and roots of the seedlings were then measured and the percentage of germination and the inhibition of each extract were calculated. Tomato was the most sensitive to the extracts, followed by watercress, onion and lettuce. The extracts with stronger activity were AcOEt, acetone and the liquid-liquid extraction, indicating the fractions that may contain the active principles of the leaves in this species

Assessing the returns to water harvesting: A meta-analysis.

This study presents the results of a meta-analysis of the peer reviewed literature on water harvesting technologies, with a focus on the crop yield impacts of water harvesting in semi-arid Africa and Asia. Main aim of the analysis is to assess whether water harvesting significantly improves crop yields, and whether the type of water harvesting technology and the quality of the rainy season correlate with the change in yield. We find that water harvesting improves crop yields significantly, and that the relative impact of water harvesting on crop yields is largest in low rainfall years. Smallholder farmers may still be reluctant to invest in water harvesting, however, as in regions with low agricultural productivity the returns to investment are limited. Finally, our review of the literature suggests that there is only a limited number of studies that has systematically evaluated the crop yield impacts of water harvesting technologies. More work is needed to strengthen the scientific knowledge base

Teachers as ‘reform-doers’ : developing a participatory curriculum to teach English as a foreign language

In this article I investigate the process of an in-service programme for English-as-a-foreign-language (EFL) teachers in Argentina started in 2007. Teachers began to feel uneasy about the EFL curriculum for secondary education at the time, feeling that something should be done to develop a participatory curriculum to be implemented in the future. The Ministry of Education approached me to develop a programme based on teachers’ concerns as they were initially willing to design in-service opportunities according to teachers’ suggestions. I organised my action-research-based programme into three sets of meetings: the first set for curriculum evaluation, the second set for learning about specific didactics, and the third set for developing a new curriculum with the hope it could be useful in the future. This teacher-developed curriculum is the basis of the 2012 EFL Curriculum as part of a new educational reform