Organic acids are abundant constituents of ripe fruits and are responsible for their sourness. In addition, they contribute to their flavour. In many fruits, the most abundant organic acids are malic and citric. The aims of this review are two-fold. The first is to provide a clear overview of malic and citric acids in the flesh of fruits. The abundance of different organic acids in commercially grown fruits is described. How this abundance changes during fruit development is outlined. The metabolic pathways used in the synthesis and dissimilation of malic and citric acids in fruits are described. The functions of malic and citric acids in the flesh of fruits are discussed. Secondly, how environmental and cultural practices can alter the organic acid content of fruits is considered.

Los ácidos orgánicos son componentes abundantes de los frutos maduros y responsables de la acidez, además contribuyen en su sabor. En muchos frutos, los ácidos más abundantes son el málico y el cítrico. Los objetivos de esta revisión son, en primer lugar, proporcionar una reseña clara respecto de los ácidos málico y cítrico en los frutos. Se describe la abundancia de diferentes ácidos en frutos cultivados comercialmente, la manera en que esta abundancia cambia durante el desarrollo de los frutos y las rutas metabólicas usadas en la síntesis y la desasimilación de los ácidos málico y cítrico en los frutos; adicionalmente, se discute sobre las funciones de estos ácidos en la pulpa de los frutos. En segundo lugar, se aborda la manera en que las prácticas ambientales y culturales pueden alterar el contenido de los ácidos orgánicos en frutos.

In 2004, WHO and the United Nations Children's Fund (UNICEF) released a joint statement recommending a new lower osmolarity oral rehydration salts (ORS) formulation and zinc supplementation for diarrhoea management. More than 5 years later, diarrhoea remains the second leading cause of death and few children in developing countries are receiving these life-saving interventions. Many countries are stalled in the technicalities of adapting national policy, while others struggle to find the funds for start-up activities. For nearly all countries, zinc supplements for children are not available locally; thus, zinc procurement continues to be a major obstacle. Global resources have not been sufficient to bring diarrhoea management to the forefront; thus, the introduction of these new recommendations has remained slow. Revitalizing diarrhoea management must become an international priority if we are going to reduce the burden of diarrhoea deaths and overall child mortality around the world.

En 2004, la OMS y el Fondo de las Naciones Unidas para la Infancia (UNICEF) difundieron una declaración conjunta en la que recomendaban una nueva preparación de sales de rehidratación oral (SRO) de baja osmolaridad y suplementos de zinc como tratamiento de la diarrea. Más de cinco años después, la diarrea sigue siendo la segunda causa de muerte, y en los países en desarrollo son muy pocos los niños que se benefician de esas intervenciones que salvan vidas. Muchos países están paralizados debatiendo detalles técnicos para adaptar su política nacional, mientras otros intentan con dificultad encontrar los fondos necesarios para iniciar sus actividades. En casi todos los países, no es posible encontrar localmente suplementos de zinc para la población infantil, y esos problemas para adquirir zinc siguen siendo un gran obstáculo. Los recursos mundiales no han sido suficientes para resaltar la importancia del tratamiento de la diarrea, de ahí la lentitud en la aplicación de las nuevas recomendaciones. La reactivación del tratamiento de la diarrea debe constituir una prioridad internacional si deseamos reducir la carga de mortalidad a ella asociada y la mortalidad general en la niñez en todo el mundo.

En 2004, l'OMS et le Fonds des Nations Unies pour l'enfance (UNICEF) ont émis une déclaration conjointe recommandant une nouvelle formulation de sels de réhydratation orale (SRO) à plus faible osmolarité et une supplémentation en zinc pour la prise en charge des diarrhées. Plus de 5 ans après, les diarrhées restent la deuxième cause de décès et peu d'enfants dans les pays en développement bénéficient de ces interventions, capables de sauver des vies. De nombreux pays sont bloqués par des détails techniques dans l'adaptation de leur politique nationale, tandis que d'autres luttent pour trouver des sources de financement pour les opérations de lancement. Dans leur quasi-totalité, les pays ne disposent pas localement de suppléments pédiatriques en zinc ; se procurer ces suppléments demeure donc un obstacle majeur. Les ressources mondiales n'ont pas suffi pour faire passer la prise en charge des diarrhées au premier plan des interventions. Ainsi, l'introduction de ces nouvelles recommandations est restée lente. Donner un nouvel élan à la prise en charge des diarrhées doit devenir une priorité internationale si l'on veut réduire la charge de mortalité due à ces maladies et la mortalité infantile globale partout dans le monde.

The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found in the macrogametocyte stage of Coccidia. The oocyst wall is over 90% protein but few of these proteins have been studied. One group is cysteine-rich and may be presumed to crosslink via disulphide bridges, though this is yet to be investigated. Another group of wall proteins is rich in tyrosine. These proteins, which range in size from 8-31 kDa, are derived from larger precursors of 56 and 82 kDa found in the wall forming bodies. Proteases may catalyze processing of the precursors into tyrosine-rich peptides, which are then oxidatively crosslinked in a reaction catalyzed by peroxidases. In support of this hypothesis, the oocyst wall has high levels of dityrosine bonds. These dityrosine crosslinked proteins may provide a structural matrix for assembly of the oocyst wall and contribute to its resilience.

Este artigo examina as relações entre as características sociodemográficas das famílias de pequenos produtores na Amazônia e a hipótese do ciclo de vida no processo de tomada de decisão de desmatar. A análise foi conduzida combinando informações de sensoriamento remoto e de sistema de informações geográficas com dados primários de 153 pequenos produtores estabelecidos ao longo da rodovia Transamazônica. Análises de regressões foram efetuadas juntamente com testes de autocorrelação espacial. Os resultados levaram à conclusão de que as características sociodemográficas das famílias, bem como fatores institucionais e de mercado, influenciam a tomada de decisão de uso da terra. Esses resultados permitem concluir ainda que, apesar de não serem muito populares entre os cientistas sociais brasileiros, os dados obtidos através das imagens de satélite podem ser muito úteis neste tipo de estudo. Além disso, a pesquisa aqui apresentada indica que dados sociodemográficos da família, bem como os de mercado, podem resultar em problemas de má especificação do modelo. O mesmo se aplica a modelos que não incorporem análises espaciais.

This paper examines the relationships between the sociodemographic characteristics of small settlers in the Brazilian Amazon and the life cycle hypothesis in the process of deforestation. The analysis was conducted combining remote sensing and geographic data with primary data of 153 small settlers along the Transamazon Highway. Regression analyses and spatial autocorrelation tests were conducted. The results from the empirical model indicate that sociodemographic characteristics of households, as well as institutional and market factors, affect the land use decision. Although remotely sensed information are not yet very popular among Brazilian social scientists, these results confirm that they can be very useful for this kind of study. Furthermore, the research presented by this paper strongly indicates that family and sociodemographic data, as well as market data, may result in misspecification problems. The same applies to models that do not incorporate spatial analysis.