773 research outputs found

    Product and other fine structure in polynomial resolutions of mapping spaces

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    Let Map_T(K,X) denote the mapping space of continuous based functions between two based spaces K and X. If K is a fixed finite complex, Greg Arone has recently given an explicit model for the Goodwillie tower of the functor sending a space X to the suspension spectrum \Sigma^\infty Map_T(K,X). Applying a generalized homology theory h_* to this tower yields a spectral sequence, and this will converge strongly to h_*(Map_T(K,X)) under suitable conditions, e.g. if h_* is connective and X is at least dim K connected. Even when the convergence is more problematic, it appears the spectral sequence can still shed considerable light on h_*(Map_T(K,X)). Similar comments hold when a cohomology theory is applied. In this paper we study how various important natural constructions on mapping spaces induce extra structure on the towers. This leads to useful interesting additional structure in the associated spectral sequences. For example, the diagonal on Map_T(K,X) induces a `diagonal' on the associated tower. After applying any cohomology theory with products h^*, the resulting spectral sequence is then a spectral sequence of differential graded algebras. The product on the E_\infty -term corresponds to the cup product in h^*(Map_T(K,X)) in the usual way, and the product on the E_1-term is described in terms of group theoretic transfers. We use explicit equivariant S-duality maps to show that, when K is the sphere S^n, our constructions at the fiber level have descriptions in terms of the Boardman-Vogt little n-cubes spaces. We are then able to identify, in a computationally useful way, the Goodwillie tower of the functor from spectra to spectra sending a spectrum X to \Sigma ^\infty \Omega ^\infty X.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-28.abs.htm

    Herd It in the Gobi: Deserting pastoralism?

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    Global drylands host more than USD 1 trillion in resource extraction investments, which serve to reconfigure communities and landscapes. In Mongoliaā€™s Gobi Desert mega-mining brings social challenges and environmental changes that question if nomadic herding and mining can coexist. Whilst company and community conflict are common, nascent frameworks and mediation models suggest alternate ways to resolve the miningā€“community conundrum. Here we investigate environmental transformations that herders encounter in the presence of the Oyu Tolgoi mega-mine in Mongoliaā€™s Khanbogd soum (district). Using socio-economic and physical data collected through interviews, field studies and climate records, we assessed local engagement and adaptation to largescale mining. Combining qualitative and quantitative methods enabled us to examine the implications of mining for herder lives and lands in an integrated way. This study presents a holistic assessment of the roles of herders, governments and mines in reshaping pastoralism. In our chosen case study, we find thatā€”contrary to common narrativesā€”mining and herding can, and do, coexist in Khanbogd soum, though ongoing challenges exist which deserve critical attention.info:eu-repo/semantics/publishedVersio

    Electrostatic colloid-membrane complexation

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    We investigate numerically and on the scaling level the adsorption of a charged colloid on an oppositely charged flexible membrane. We show that the long ranged character of the electrostatic interaction leads to a wrapping reentrance of the complex as the salt concentration is varied. The membrane wrapping depends on the size of the colloid and on the salt concentration and only for intermediate salt concentration and colloid sizes we find full wrapping. From the scaling model we derive simple relations for the phase boundaries between the different states of the complex, which agree well with the numerical minimization of the free energy.Comment: 7 page, 11 figure

    Cortical Thickness and Surface Area Networks in Healthy Aging, Alzheimerā€™s Disease and Behavioral Variant Fronto-Temporal Dementia

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    Acknowledgments We would like to acknowledge the support of the Maxwell compute cluster funded by the University of Aberdeen. We also gratefully acknowledge study investigators and the generosity of study participants.Peer reviewedPublisher PD

    Fuzzy approximate entropy analysis of resting state fMRI signal complexity across the adult life span

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    Acknowledgment The authors would like to acknowledge the work of the International Consortium for Brain Mapping (ICBM) fMRI community in creating the resting state database and making it publicly available within the framework of the 1000 Functional Connectomes project (https://www.nitrc.org/projects/fcon_1000/). M.O. Sokunbi was supported by an MRC grant G1100629.Peer reviewedPreprin

    Klotho, APOEĪµ4, cognitive ability, brain size, atrophy and survival : A study in the Aberdeen Birth Cohort of 1936

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    We thank the cohort participants who contributed to these studies. The study was supported by the University of Aberdeen Development Trust; the UKā€™s Biotechnology and Biological Sciences Research Council (BBSRC); the Wellcome Trust; the Chief Scientist Office (Scotland); and the Alzheimerā€™s Research Trust (now ARUK).Peer reviewedPostprin

    The net value added approach as a tool for integration at the micro level

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    There are major changes in the structure of farms and farm households, the levels of enumeration in agricultural statistics, and in the linkages between these levels. To record and enhance understanding of these developments this paper proposes use of a net value added (NVA) approach at the micro level to reflect the participation of a wide variety of stakeholders in the organization and output of farms. NVA is widely used and internationally standardized. NVA concepts can be applied at the micro level to show to which stakeholders the income of the farm is distributed. We show in the paper that stakeholder involvement and distribution of NVA differs among countries, based on economic opportunities and institutions. Being aware of such differences is relevant in the international policy context because many policies involve distributional impacts, particularly for income and wealth. Based on results, we present an agenda for future work to promote the international integration of micro economic statistics in agricultur
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