Building capacity for modeling in Africa

The use of models in decision support is important as field experiments provide empirical data on responses to only a small number of possible combinations of climate, soil, and management situations. Yet, crop modeling by African scientists so far has been limited. Therefore, to build the capacity of African scientists in the use of decision support systems, a provision was made for training within two main projects: Water Challenge Project (WCP) and Desert Margins Programme (DMP), jointly led by TSBF-CIAT (Tropical Soil Biology and Fertility Institute of the International Centre for Tropical Agriculture) and International Centre for Research in the Semiarid Tropics (ICRISAT). A unique approach to training on modeling was developed and was based on four main pillars: (a) learning by doing, (b) integrated follow-up, (c) continuous backstopping support and (d) multi-level training embedded in a series of three training workshops. Although crop models are useful they have limitations. For instance, they do not account for all of the factors in the field that may influence crop yield and inputs must be accurate for simulated outputs to match observations from the field. Thus it is imperative that these issues are carefully considered and weighted before attempting to evaluate the predictability of a crop model. However, the use of crop models and decision support systems in concert with experiments can provide very useful alternative management options for resource-poor farmers in Africa and other regions across the glob

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference