264 research outputs found

    Multi Parametric Deformed Heisenberg Algebras: A Route to Complexity

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    We introduce a generalization of the Heisenberg algebra which is written in terms of a functional of one generator of the algebra, f(J0)f(J_0), that can be any analytical function. When ff is linear with slope θ\theta, we show that the algebra in this case corresponds to qq-oscillators for q2=tanθq^2 = \tan \theta. The case where ff is a polynomial of order nn in J0J_0 corresponds to a nn-parameter deformed Heisenberg algebra. The representations of the algebra, when ff is any analytical function, are shown to be obtained through the study of the stability of the fixed points of ff and their composed functions. The case when ff is a quadratic polynomial in J0J_0, the simplest non-linear scheme which is able to create chaotic behavior, is analyzed in detail and special regions in the parameter space give representations that cannot be continuously deformed to representations of Heisenberg algebra.Comment: latex, 17 pages, 5 PS figures; to be published in J. Phys. A: Math and Gen (2001); a few sentences were added in order to clarify some point

    The South Green Bioinformatics platform, a comprehensive resource for crop genomics

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    Analysis and visualization of massive genomics datasets are an ongoing trend in plant sciences. The South Green Bioinformatics platform provides an ecosystem of tools that were originally developed as independent entities to fulfill the need for specific projects or crops, but have evolved over time to generic tools to comprehensively study crop genomics. We have built a large panel of public information systems dedicated to specialized datasets (markers, genes, gene families, transcriptomes, genotypes, phenotypes, etc.) and crop-specific resources called Genome Hubs. Target users of bioinformatic analytical workflows are usually divided between people who use command-line and those who do not. We addressed both categories by offering complementary solutions, like Galaxy-based and command-line applications. Various groups used the South Green infrastructure to obtain their data and results, and were able to publish high-quality biological information, on Coffee genome, Banana, Cocoa, African rice or large transcriptome resources. Tools developed for these studies are adaptable to a wide range of other organisms

    Some data on allele diversity at orthologous candidate genes in GCP crops : [P234]

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    The ADOC project (GCP 2006-02) aimed to characterize allelic diversity at orthologous loci of candidate genes for drought tolerance in seven GCP crops (rice, barley, sorghum, bean, chickpea, cassava and potato), working on reference collections of around 300 accessions for each crop. Six gene families (ERECTA, DREB, SS, SPS, ASR and VIN) were selected as the initial subset of target genes. Except the DREB gene family, for which a specific focus has been given to DREB2A, and the SPS gene family in cereals, for which only the Os01g69030 orthology group was studied, they represent a set of relatively small gene families acting at different levels of the drought stress response (transcriptional regulation, carbohydrate metabolism...) for which a comparative analysis of gene families was undertaken. Obtaining complete gene families was easier in whole sequenced genomes like rice and sorghum. Polyploidy and heterozygosity induced difficulties in analyzing data for cassava and potato; However sequences for a few genes were obtained and analyzed for SNP diversity across all species. Population structure influenced partially haplotype patterns. A large range of haplotype diversity was found and the degrees of this differed between species. Different patterns and range of sequence diversity were found within gene families and between species for orthologous genes. For a few genes, computation of a sequence-based neutrality test suggested selection events acting at the species and/or subgroup level. (Texte intégral

    The Campbells: lordship, literature and liminality

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    The Campbells have the potential to offer much to the theme of literature and borders, given that the kindred’s astonishing political success in the late medieval and early modern period depended heavily upon the ability to negotiate multiple frontiers: between Highlands and Lowlands; between Gaelic Scotland and Ireland, and, especially after the Reformation, with England and the matter of Britain. This paper will explore the literary dimension to Campbell expansionism, from the Book of the Dean of Lismore in the earlier sixteenth century, to poetry addressed to dukes of Argyll in the earlier eighteenth century. Particular attention will be paid to the literary proclivities of the household of the Campbells of Glenorchy on either side of what appears to be a major watershed in 1550; and to the agenda of the Campbell protégé John Carswell, first post-Reformation bishop of the Isles, and author of the first printed book in Gaelic in either Scotland or Ireland, Foirm na n-Urrnuidheadh (‘The Form of Prayers’), published at Edinburgh in 1567

    The Law of Society: Governance Through Contract

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    This paper focuses on contract law as a central field in contemporary regulatory practice. In recent years, governance by contract has emerged as the central concept in the context of domestic privatization, domestic and transnational commercial relations and law-and-development projects. Meanwhile, as a result of the neo-formalist attack on contract law, governance of contract through contract adjudication, consumer protection law and judicial intervention into private law relations has come under severe pressure. Building on early historical critique of the formalist foundations of an allegedly private law of the market, the paper assesses the current justifications for contractual governance and posits that only an expanded legal realist perspective can adequately explain the complex nature of contractual agreements in contemporary practice. The paper argues for an understanding of contracts as complex societal arrangements that visibilize and negotiate conflicting rationalities and interests. Institutionally, contractual governance has been unfolding in a complex, historically grown and ideologically continually contested regulatory field. Governance through contract, then, denotes a wide field of conflicting concepts, ideas and symbols, that are themselves deeply entrenched in theories of society, market and the state. From this perspective, we are well advised to study contracts in their socio-economic, historical and cultural context. A careful reading of scholars such as Henry Sumner Maine, Morris Cohen, Robert Hale, Karl Llewellyn, Stewart Macaulay and Ian Macneil offers a deeper understanding of the institutional and normative dimensions of contractual governance. Their analysis is particularly helpful in assessing currently ongoing shifts away from a welfare state based regulation (governance) of contractual relations. Such shifts are occurring on two levels. First, they take place against the backdrop of a neo-liberal critique of government interference into allegedly private relations. Secondly, the increasingly influential return to formalism in contract law, which privileges a functionalist, purportedly technical and autonomous design and execution of contractual agreements over the view of regulated contracts, is linked to a particular concept of sovereignty. The ensuing revival of freedom of contract occurs in remarkable neglect of the experiences of welfare state adjudication of private law adjudication and a continuing contestation of the political in private relationships. The paper takes up the Legal Realists\u27 search for the \u27basis of contract\u27, but seeks to redirect the focus from the traditional perspective on state vs. market to a disembedded understanding of contractual governance as delineating multipolar and multirational regulatory regimes. Where Globalization has led to a fragmentation, disembeddedness and transnationalization of contexts and, thus, has been challenging traditional understanding of embeddedness, the task should no longer be to try applying a largely nation-state oriented Legal Realist perspective and critique to the sphere of contemporary contractual governance, but - rather - to translate its aims into a more reflexive set of instruments of legal critique. Even if Globalization has led to a dramatic denationalization of many regulatory fields and functions, it is still not clear, whether and how Globalization replaces, complements or aggravates transformations of societal governance, with and through contract

    Assessing the Carcinogenic Potential of Low-Dose Exposures to Chemical Mixtures in the Environment: The Challenge Ahead

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety \u27Mode of Action\u27 framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
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