346 research outputs found

    The de Rham homotopy theory and differential graded category

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    This paper is a generalization of arXiv:0810.0808. We develop the de Rham homotopy theory of not necessarily nilpotent spaces, using closed dg-categories and equivariant dg-algebras. We see these two algebraic objects correspond in a certain way. We prove an equivalence between the homotopy category of schematic homotopy types and a homotopy category of closed dg-categories. We give a description of homotopy invariants of spaces in terms of minimal models. The minimal model in this context behaves much like the Sullivan's minimal model. We also provide some examples. We prove an equivalence between fiberwise rationalizations and closed dg-categories with subsidiary data.Comment: 47 pages. final version. The final publication is available at http://www.springerlink.co

    Deformation quantisation for unshifted symplectic structures on derived Artin stacks

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    We prove that every 00-shifted symplectic structure on a derived Artin nn-stack admits a curved A∞A_{\infty} deformation quantisation. The classical method of quantising smooth varieties via quantisations of affine space does not apply in this setting, so we develop a new approach. We construct a map from DQ algebroid quantisations of unshifted symplectic structures on a derived Artin nn-stack to power series in de Rham cohomology, depending only on a choice of Drinfeld associator. This gives an equivalence between even power series and certain involutive quantisations, which yield anti-involutive curved A∞A_{\infty} deformations of the dg category of perfect complexes. In particular, there is a canonical quantisation associated to every symplectic structure on such a stack, which agrees for smooth varieties with the Kontsevich--Tamarkin quantisation for even associators.Comment: 27pp.; v2 Propositions 1.23 and 3.10 added; v3 several small additions; v4 several changes following referee's comments, to appear in Select

    The failed liberalisation of Algeria and the international context: a legacy of stable authoritarianism

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    The paper attempts to challenge the somewhat marginal role of international factors in the study of transitions to democracy. Theoretical and practical difficulties in proving causal mechanisms between international variables and domestic outcomes can be overcome by defining the international dimension in terms of Western dominance of world politics and by identifying Western actions towards democratising countries. The paper focuses on the case of Algeria, where international factors are key in explaining the initial process of democratisation and its following demise. In particular, the paper argues that direct Western policies, the pressures of the international system and external shocks influence the internal distribution of power and resources, which underpins the different strategies of all domestic actors. The paper concludes that analysis based purely on domestic factors cannot explain the process of democratisation and that international variables must be taken into more serious account and much more detailed

    The ASEAN community-based tourism standards: looking beyond certification

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    This paper reports findings from an opportunity study on the appropriateness of implementing community-based tourism standards (CBTS) certification through the Association of Southeast Asian Nations (ASEAN) criteria, as a way to improve sustainable tourism provision in the region. Framed by critical reflections on community-based tourism (CBT) literature and existing sustainable tourism standards (STS) practices, qualitative research consisting of interviews with six key industry experts provided core insights into a number of CBTS’ implementation challenges. Findings indicate the main hindering factors for the implementation of CBTS to be the lack of adequate governance, limited funding and insufficient community capacity. The study concluded that although at the moment the full implementation of CBTS as a certification programme would be premature, ASEAN-CBTS’ criteria are a useful benchmarking and strategic planning tool for local communities, which would eventually lead to improved CBT benefits, standards and performance in the region. At the same time, this paper argues that aspects including CBT competitiveness and service delivery need to be tackled first to create fruitful grounding for CBT certification

    The challenges of renewed independence: The Baltic states since 1991

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    This article offers a comparative assessment of how successfully Estonia, Latvia, and Lithuania have coped with the challenges of renewed independence since 1991, focusing on various aspects of political, economic, and social development. In the post-communist context the Baltic states have clearly outpaced other former Soviet republics and also performed reasonably well in comparison to the countries of Eastern Europe. The convergence of the Baltic experience, which began already in the early 20th century, has continued in the recent past as well, as the three states have adopted a number of similar approaches in domestic politics, the search for security, and economic policy. They also face a number of similar unsolved problems, including considerable political alienation, tensions in relations with Russia, socioeconomic disparity, and demographic challenges. The most important difference in the issues confronting the Baltic states today continues to be the large non-Baltic, mainly Russian presence in Estonia and Latvia, a result of Soviet-era policies. How to effect the meaningful integration of a multiethnic society remains a continuing challenge in these two countries. In contrast, population shifts under Soviet rule never became massive in Lithuania, and ethnic relations are a minor issue there today

    The double-design dilemma : political science, parliamentary crisis and disciplinary justifications

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    Two separate, but inter-linked, dilemmas have highlighted the importance of design-led thinking. First, the crumbling physical fabric of the Palace of Westminster has prompted a multi-billion rebuilding project, which will require the parliamentary studies specialism to engage with questions of design, space, and architecture. Separately, political science more generally has been challenged to utilize the insights of design-thinking and design-practice: a challenge to which it is culturally and methodological ill-equipped. This article considers what a design-led approach to political science looks like in theory, and in practice, in the case study of the Restoration and Renewal of the Palace of Westminster. This represents a first attempt at how such a fusion could be beneficial for both politics as theory and politics as practice. The main conclusion is that although design-orientated political science is not a panacea for the challenges of modern democratic governance – in intellectual or practical terms – it does appear to offer significant potential in terms of theoretically-informed but solution focused research

    Finding Diagnostically Useful Patterns in Quantitative Phenotypic Data.

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    Trio-based whole-exome sequence (WES) data have established confident genetic diagnoses in ∌40% of previously undiagnosed individuals recruited to the Deciphering Developmental Disorders (DDD) study. Here we aim to use the breadth of phenotypic information recorded in DDD to augment diagnosis and disease variant discovery in probands. Median Euclidean distances (mEuD) were employed as a simple measure of similarity of quantitative phenotypic data within sets of ≄10 individuals with plausibly causative de novo mutations (DNM) in 28 different developmental disorder genes. 13/28 (46.4%) showed significant similarity for growth or developmental milestone metrics, 10/28 (35.7%) showed similarity in HPO term usage, and 12/28 (43%) showed no phenotypic similarity. Pairwise comparisons of individuals with high-impact inherited variants to the 32 individuals with causative DNM in ANKRD11 using only growth z-scores highlighted 5 likely causative inherited variants and two unrecognized DNM resulting in an 18% diagnostic uplift for this gene. Using an independent approach, naive Bayes classification of growth and developmental data produced reasonably discriminative models for the 24 DNM genes with sufficiently complete data. An unsupervised naive Bayes classification of 6,993 probands with WES data and sufficient phenotypic information defined 23 in silico syndromes (ISSs) and was used to test a "phenotype first" approach to the discovery of causative genotypes using WES variants strictly filtered on allele frequency, mutation consequence, and evidence of constraint in humans. This highlighted heterozygous de novo nonsynonymous variants in SPTBN2 as causative in three DDD probands
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