Famine, drought and plagues.

Analiza las causas y los efectos de las sequías y plagas y las medidas que podrían adoptarse para reducir sus efectos. Los ejemplos y los estudios de casos de desastres anteriores demuestran con más detalle el impacto de estos desastres. El texto es claro, con conceptos difíciles expuestos de manera comprensible.

Food & Famine.

El uso de ejemplos para demostrar un entendimiento de los conceptos y procesos en geografía física y humana es un requisito básico para un exitoso examen en AS y A2. Esta serie ofrece estudios de casos actualizados y seleccionados, para que así tu puedas contestar a los ejercicios del libro. El libro consta de ocho partes: modelos globales de producción y consumo de alimentos, patrones globales de seguridad alimentaria e inseguridad, el hambre y la vida de los marginados, jugadores poderosos en la cadena alimentaria mundial, impactos medioambientales, estrategias para aumentar la producción de comida y la seguridad en el mundo, cuestiones relativas a la seguridad alimentaria y la sostenibilidad y consejos de exámenes.

Mechanistic insights from the crystal structures of a feast/famine regulatory protein from Mycobacterium tuberculosis H37Rv

Rv3291c gene from Mycobacterium tuberculosis codes for a transcriptional regulator belonging to the (leucine responsive regulatory protein/regulator of asparigine synthase C gene product) Lrp/AsnC-family. We have identified a novel effectorbinding site from crystal structures of the apo protein, complexes with a variety of amino acid effectors, X-ray based ligand screening and qualitative fluorescence spectroscopy experiments. The new effector site is in addition to the structural characterization of another distinct site in the protein conserved in the related AsnC-family of regulators. The structures reveal that the ligandbinding loops of two crystallographically ndependent subunits adopt different conformations to generate two distinct effector-binding sites. A change in the conformation of the binding site loop 100–106 in the B subunit is apparently necessary for octameric association and also allows the loop to interact with a bound ligand in the newly identified effector-binding site. There are four sites of each kind in the octamer and the protein preferentially binds to aromatic amino acids. While amino acids like Phe, Tyr and Trp exhibit binding to only one site, His exhibits binding to both sites. Binding of Phe is accompanied by a conformational change of 3.7A ° in the 75–83 loop, which is advantageously positioned to control formation of higher oligomers. Taken together, the present studies suggest an elegant control mechanism for global transcription regulation involving binding of ligands to the two sites, individually or collectively.

Famine responses in the world food crisis 1972–5 and the World Food Conference of 1974

In the early 1970s, there was scarcity in the world grain market, soaring prices and famines in several countries of Asia and Africa. The commercial grain trade was expanded at the expense of food aid. After a brief look at policies addressing the situation in terms of modernised methods of agricultural production for small producers, the article sketches how such policies also affected relief efforts, from the low availability for food aid, the provision of food that was not useful and late deliveries through efforts to tie food aid to local changes in agricultural production and settlement patterns. In part, food aid thus reinforced processes of social differentiation that had contributed to causing the famines in the first place.