Decentring poverty, reworking government: social movements and states in the government of poverty.

The significance of social movements for pro-poor political and social change is widely acknowledged. Poverty reduction has assumed increasing significance within development debates, discourses and programmes - how do social movement leaders and activists respond? This paper explores this question through the mapping of social movement organisations in Peru and South Africa. We conclude that for movement activists 'poverty' is rarely a central concern. Instead, they represent their actions as challenging injustice, inequality and/or development models with which they disagree, and reject the simplifying and sectoral orientation of poverty reduction interventions. In today's engagement with the poverty-reducing state, their challenge is to secure resources and influence without becoming themselves subject to, or even the subjects of, the practices of government.

Origin and genetic diversity of Western European populations of the potato cyst nematode (Globodera pallida) inferred from mitochondrial sequences and microsatellite loci.

Native to South America, the potato cyst nematode Globodera pallida is one of the principal pests of Andean potato crops and is also an important global pest following its introduction to Europe, Africa, North America, Asia and Oceania. Building on earlier work showing a clear south to north phylogeographic pattern in Peruvian populations, we have been able to identify the origin of Western European populations with high accuracy. They are all derived from a single restricted area in the extreme south of Peru, located between the north shore of the Lake Titicaca and Cusco. Only four cytochrome b haplotypes are found in Western Europe, one of them being also found in some populations of this area of southern Peru. The allelic richness at seven microsatellite loci observed in the Western European populations, although only one-third of that observed in this part of southern Peru, is comparable to the allelic richness observed in the northern region of Peru. This result could be explained by the fact that most of the genetic variability observed at the scale of a field or even of a region is already observed at the scale of a single plant within a field. Thus, even introduction via a single infected potato plant could result in the relatively high genetic variability observed in Western Europe. This finding has important consequences for the control of this pest and the development of quarantine measures.

Inbreeding and population structure of the potato cyst nematode (Globodera pallida) in its native area (Peru).

The dispersal abilities and the population genetic structure of nematodes living in the soil are poorly known. In the present study, we have pursued these issues in the potato cyst nematode Globodera pallida, which parasitizes potato roots and is indigenous to South America. A hierarchical sampling regime was conducted in Peru to investigate gene flow on regional, field and plant scales. Multilocus genotypes of single individuals were obtained using eight polymorphic microsatellites markers. Large heterozygote deficiencies were observed at most loci. The limited active dispersal of larvae from their cyst, which favours mating between (half) siblings, could be responsible for this pattern. Within fields, as well as among fields within regions (even 35 km apart), low F(ST) values suggest extensive gene flow. Among fields within regions, only 1.5-4.4% genetic variability was observed. Passive dispersal of cysts by natural means (wind, running water, or wild animals) or by anthropogenic means (tillage, movement of infected seed tubers) is probably responsible for the results observed. Among regions, high F(ST) values were observed. Thus long-range dispersal (more than 320 km apart) is probably limited by major biogeographical barriers such as the mountains found in the Andean Cordillera. These results provide useful information for the management of resistant varieties, to slow down the emergence and spread of resistance-breaking pathotypes.

Cognitive model of problem-solving in chess.

By performing a series of five experiments with two subjects, several aspects of one of the subject's behavior in solving chess problems were found to be predictable, and a model was developed to explain this predictability. The heuristics used in this model may be applicable in developing future computer programs for chess play.