When humans carry out actions in response to some external stimulation, they acquire associations between the stimulus and the action it triggered. These stimulus-response associations are the basis for the automatic aspects of human performance: The tighter the link between stimulus and response, the faster the motor action is carried out upon stimulus presentation (cf. Logan, 1988). However, the particular flexibility of human behavior roots in humans? ability to act in a way that is not completely stimulus-driven. Stimuli often afford more than only one action and humans are able to select among these actions according to the context and their intentions. That is, humans "complement" stimulus information with some top-down control mechanism that takes care that stimulus-driven schemas activated at the same time are "channeled" in accordance with the agent?s intentions (e.g., Norman & Shallice, 1986). The importance of top-down control mechanisms guiding bottom-up schemas becomes especially obvious when they malfunction: "Utilisation behavior" is characterized by inability to inhibit actions from being triggered by the mere sight of an object with which the action is habitually associated (Lhermitte, 1983). Still, automatic and executive processes are traditionally explored with different experimental techniques. Top-down processes have been investigated with a number of paradigms studying processes like resource allocation, module configuration, step sequencing, outcome monitoring, troubleshooting, and so forth (see Monsell, 1996). In contrast, bottom-up influences on performance have been explored typically with priming techniques, which focus on effects driven by stimuli and their associations and/or by immediately preceding processing states. The current project abolishes this separation between controlled and automatic aspects of behavior. It does not only explore the properties of S-R associations but investigates also the conditions in which involuntary retrieval, based on prior S-R episodes, is liable to have significant effects on performance. It will do so by using an integrative approach that applies techniques coming from several disciplines: experimental psychology (reaction times), neurophysiology (event-related potentials [ERPs], induced gamma-band responses [iGBR], transcranial magnetic stimulation [TMS]), and neuropsychology (lesion studies).

Numerical tables were one of the most commonly used instruments of calculation from the earliest periods for which we have evidence of mathematical activity until the appearance of computing machines. By 'numerical tables', we mean a broad category of texts that establish correspondences between two or more quantitative or qualitative phenomena and attempt to exhibit, on a plane surface, in some determinate way, numerical values that correspond to these phenomena. Such tables are interesting both as tools of calculation and insofar as evidence for certain social and scientific activities of the practitioners by, and for, whom they were produced. Nevertheless, despite the fact that the historical record has preserved thousands of tables from a broad range of civilizations, these tables have themselves received relatively little critical study. Hence, it has seemed to us both useful and innovative to consider broadly and for the first time the problem of tables in general by bringing together specialists of the different mathematical traditions (Egypt, Mesopotamia, Greece, India, China, the Arabic World, Europe since the Middle Ages) and of the different context for the development of tables (astrology, astronomy, metrology, arithmetic, mathematical analysis, numerical calculation, mechanics, physical sciences, engineering, school mathematics, administration and management, etc.). It is our expectation that this will allow us to make significant breakthroughs in our understanding of the places and roles of tables in the history of the sciences.

Global environmental threats, in particular climate change, have been identified as potential causes of large migration flows in the future (UNFPA, 2001). Although the climate is a global good, available projections indicate that climate change damages will differ significantly according to region and affect developing countries more than developed countries (IPCC, 2007). Future projections show a significant impact on African migration flows following climate-change induced water stress (Le Blanc and Perez, 2008). The objective of the project is to study the interlinkages between environmental policy and migration. Although this topic has been extensively researched in the geographical sciences, little modelling has so far been done on the economic trade-offs, and in fact, the literature lacks economic studies of the environment as a potential push factor for migration. The project proposes to undertake theoretical and empirical modelling of environment and migration in three interrelated parts. The first objective is to formulate a theoretical model of the policy-maker's choice when there are international externalities from pollution that may induce migration in a future time period. Although some attempts have been made to capture the simultaneous choice of environmental objectives when there are mobile populations, there has never been any model that has integrated the policy trade-offs between emission reductions and migration flows. The second objective is to study empirically actual migration flows, and the environmental stress that could have influenced them. Current evidence of environment-induced migration exists in Africa. We wish to focus on this region because of the uneven impact of climate change, which has been shown to particularly affect the less developed countries, and particularly those who are exposed to severe water stress and where the adaptive capacity may lead to environmentally induced migration. We propose to use an exceptional household panel dataset from Ethiopia on internal migrations to separate out the environmental motives for migration from other socioeconomic and political factors for migration. This micro data analysis will be complemented by regional level data on migration flows that we will confront with existing databases on climate factors from the IPCC. Barrios et al. (2006) analyzed the determinants of urbanization in Africa and in particular its relation with rainfall data, using econometric analysis on a national level, in one of the few existing studies to link economic development with environmental conditions. The proposed project will build on this study to develop a more far-reaching analysis between population flows in Africa and a larger set of environmental determinants. As such, this part of the project will constitute the first of its kind to determine the geographic and environmental determinants of the outcome of migration, namely changes in the population distribution within the African continent over the latter half of the 20th century. The third objective is to study one of the major consequences of regional or internal migration, i.e., the pollution from the informal urban sector. In fact, a large part of the migration flows in the developing world are internal and draw rural migrants to the city in search of livelihoods, and current forecasts indicate a strengthening of this trend in developing countries. This represents an entirely new subject, since apart from a few case studies on pollution emanating from the urban informal sector, little formal modelling has been done of the relevant linkages between pollution and a migrant's work choice in the formal urban sector and the informal urban sector. The aim of the project is to contribute to our understanding of the economic mechanisms that sustain the informal urban sector and how environmental policy should be designed to reduce the negative environmental externalities. We anticipate to be able to draw conclusions on alternative policy instruments to internalise the environmental externalities of the urban informal sector. We also hope to be able to develop a coherent theoretical model of the existence and size of the informal urban sector, considering the endogenous occupation choice of a migrant to the urban area.

The study of metazoan phylogeny using molecular data has led to major reorganizations in our conception of the animal phylogenetic tree. The bilaterians (bilaterally symmetrical triploblastic animals) are a monophyletic group, divided into three great branches: the deuterostomes and two large groups of protostomes, the ecdysozoans and the trochozoans. Between insects and vertebrates exist a striking number of similarities in the genetic regulation of some key-steps in the ontogeneses of structures and organs that were generally thought to have evolved several times independently in metazoans. To explain these similarities, it has been proposed that these structures and organs were present in the last common ancestor of all protostomes and deuterostomes, an annelid-like coelomate segmented animal called Urbilateria. We are testing this controversial theory of the complex Urbilateria and trying to understand how this animal lived and developed. Our team works on the development of the marine annelid Platynereis dumerilii, a representative of the trochozoan branch of the bilaterian tree, easily cultured in the lab and amenable to molecular biology techniques. We propose to investigate further two questions in the animal body plan evolution debate : 1°) How did Urbilateria make a nervous system ' What does it imply for the origin of the condensed vertebrate nervous system ' We are investigating the morphogenesis of the nervous system of Platynereis, both at the level of the fundamental process of neurogenesis and at the level of the patterning of neural architecture. Our preliminary results show that the trunk ectoderm of Platynereis is subdivided in longitudinal neurogenic columns similar to those existing in vertebrates. Expression patterns suggest that these columns are patterned by essentially the same set of homeobox genes as is known in vertebrates and these columns, according to their position are at the origin of both the central (ventral nerve cord) and peripheral (sensory cells and neurons) nervous system. We propose to explore the molecular architecture of the peripheral nervous system (PNS) of Platynereis. In vertebrates, the PNS is produced by two embryonic sources: the neural crest and the ectodermal placodes. We are going to investigate in a systematic way the expression patterns in Platynereis of the orthologues of vertebrate genes involved in the ontogenesis of the PNS, in order to determine whether embryonic territories homologous with placodes and neural crests do exist in annelids. The functions of some key genes will be tested experimentally using SiRNA or morpholino injections in fertilized eggs. With such approaches, we think we will be able to find key evidence that the complex vertebrate nervous system indeed derived from a simple annelid-like metameric pattern and even to find arguments for a scenario of the origin of this key vertebrate character, the neural crest. 2°) Was Urbilateria segmented ' Deciphering the genetic machinery that creates segmental periodicity in Platynereis by a transcriptome analysis approach. In our previous work, we have shown that the signalling pathways responsible for the individual axial patterning of ectodermal segments in Platynereis are similar to those involved in arthropod segment formation. Spatial relationships of the expression patterns of these segmentation genes suggest strongly that the ancestor of protostomes was a fully metameric animal. However, the genetic mechanisms that are responsible for creating segmental periodicity in the first place in posteriorly growing protostomes are unknown. Recent findings have shown that the mesoderm-based segmental pattern in vertebrates is regulated by cyclical waves of gene expression in the unsegmented mesoderm. These waves are controlled by the action of three signalling pathways (Notch, Wnt and FGF). In order to objectively determine the similarities and differences in segment-making genes in vertebrates and annelids, we propose to determine cyclical gene expression in the segment addition region of growing Platynereis juveniles, by transcriptome analysis using the massively parallel sequencing technology available at the GODMAP platform. We will then test hierarchical relationships between these genes and the signalling pathways potentially involved in cyclical expression such as Notch, Wnt, FGF by using specific inhibitors of these pathways. Therefore we believe our research will provide crucial elements for understanding the origins of the vertebrates. In the complex Urbilateria view, vertebrates evolved from an active annelid-like animal. We want to provide decisive arguments for two key aspects of this view : a segmented trunk and a regularly organized complex metameric nervous system.