420 research outputs found

    TGF‐β1‐activated type 2 dendritic cells promote wound healing and induce fibroblasts to express tenascin c following corneal full‐thickness hydrogel transplantation

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    ACKNOWLEDGEMENTS We are grateful to the Iain Fraser Flow Cytometry Centre, the Microscopy and Histology Facility, the Quantitative PCR Facility, and the Medical Research Facility at the University of Aberdeen. This work was supported by the Royal College of Surgeons of Edinburgh, UK and Saving Sight in Grampian/Development Trust of the University of Aberdeen, UK. Funding Information: Saving Sight in Grampian/Development Trust of the University of Aberdeen, UK Royal College of Surgeons of Edinburgh, UKPeer reviewedPostprin

    Activation of dendritic cells by crosslinked collagen hydrogels (artificial corneas) varies with their composition

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    ACKNOWLEDGEMENTS We are grateful to the Iain Fraser Flow Cytometry Centre, the Microscopy and Histology Facility, and the Medical Research Facility at the University of Aberdeen. This work was supported by the Royal College of Surgeons of Edinburgh, UK, and Saving Sight in Grampian/Development Trust of the University of Aberdeen, UK. Funding Information: Saving Sight in Grampian/Development Trust of the University of Aberdeen, UK Royal College of Surgeons of Edinburgh, UKPeer reviewedPostprin

    Watermelon configurations with wall interaction: exact and asymptotic results

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    We perform an exact and asymptotic analysis of the model of nn vicious walkers interacting with a wall via contact potentials, a model introduced by Brak, Essam and Owczarek. More specifically, we study the partition function of watermelon configurations which start on the wall, but may end at arbitrary height, and their mean number of contacts with the wall. We improve and extend the earlier (partially non-rigorous) results by Brak, Essam and Owczarek, providing new exact results, and more precise and more general asymptotic results, in particular full asymptotic expansions for the partition function and the mean number of contacts. Furthermore, we relate this circle of problems to earlier results in the combinatorial and statistical literature.Comment: AmS-TeX, 41 page

    Alpenloopings in Heimatklänge : Jodeln als Globalisierungsbewegung zwischen Tradition und Experiment

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    The subject of my contribution is the functioning and effect of yodeling as an experimental form of vocals and singing as presented in Stefan Schwieterts documentary Heimatklänge [Sounds of home] (CH/D 2007); a recursive figure that co-constitutes what is identified as home and forges a sense of identity. Yodeling enables two home »loops« of a special kind: first, the recursive calling-singing in the Swiss Alps, which returns to inside the body as a result of a specific geographic location and its echo, and second, a worldwide sounds network, which through the art of the three Swiss vocal artists Erika Stucky, Noldi Alder, and Christian Zehnder, forms an acoustic bridge from Switzerland via Mongolia to the USA. The essay follows the associative structure of the ilm, which describes a circular movement that seeks to locate the concept of home while alternating in sounds and images between region and global, own and alien, traditional and experimental. With its description of the hypothesis of the origin of yodeling the study begins with a musicological perspective; next, it present an in-depth film analysis of Heimatklänges presentation of yodeling; finally, it formulates a globalization hypothesis in the context of culture studies, which in conjunction with the film endeavours to rethink the relationship between mountain landscape and people

    Stretch goals and the distribution of organizational performance

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    Many academics, consultants, and managers advocate stretch goals to attain superior organizational performance. However, existing theory speculates that, although stretch goals may benefit some organizations, they are not a “rule for riches” for all organizations. To address this speculation, we use two experimental studies to explore the effects on the mean, median, variance, and skewness of performance of stretch compared with moderate goals. Participants were assigned moderate or stretch goals to manage a widely used business simulation. Compared with moderate goals, stretch goals improve performance for a few participants, but many abandon the stretch goals in favor of lower self-set goals, or adopt a survival goal when faced with the threat of bankruptcy. Consequently, stretch goals generate higher performance variance across organizations and a right-skewed performance distribution. Contrary to conventional wisdom, we find no positive stretch goal main effect on performance. Instead, stretch goals compared with moderate goals generate large attainment discrepancies that increase willingness to take risks, undermine goal commitment, and generate lower risk-adjusted performance. The results provide a richer theoretical and empirical appreciation of how stretch goals influence performance

    The deleted in brachydactyly B domain of ROR2 is required for receptor activation by recruitment of Src

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    The transmembrane receptor 'ROR2' resembles members of the receptor tyrosine kinase family of signalling receptors in sequence but its' signal transduction mechanisms remain enigmatic. This problem has particular importance because mutations in ROR2 are associated with two human skeletal dysmorphology syndromes, recessive Robinow Syndrome (RS) and dominant acting Brachydactyly type B (BDB). Here we show, using a constitutive dimerisation approach, that ROR2 exhibits dimerisation-induced tyrosine kinase activity and the ROR2 C-terminal domain, which is deleted in BDB, is required for recruitment and activation of the non-receptor tyrosine kinase Src. Native ROR2 phosphorylation is induced by the ligand Wnt5a and is blocked by pharmacological inhibition of Src kinase activity. Eight sites of Src-mediated ROR2 phosphorylation have been identified by mass spectrometry. Activation via tyrosine phosphorylation of ROR2 receptor leads to its internalisation into Rab5 positive endosomes. These findings show that BDB mutant receptors are defective in kinase activation as a result of failure to recruit Src

    Critical statistics for non-Hermitian matrices

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    We introduce a generalized ensemble of nonhermitian matrices interpolating between the Gaussian Unitary Ensemble, the Ginibre ensemble and the Poisson ensemble. The joint eigenvalue distribution of this model is obtained by means of an extension of the Itzykson-Zuber formula to general complex matrices. Its correlation functions are studied both in the case of weak nonhermiticity and in the case of strong nonhermiticity. In the weak nonhermiticity limit we show that the spectral correlations in the bulk of the spectrum display critical statistics: the asymptotic linear behavior of the number variance is already approached for energy differences of the order of the eigenvalue spacing. To lowest order, its slope does not depend on the degree of nonhermiticity. Close the edge, the spectral correlations are similar to the Hermitian case. In the strong nonhermiticity limit the crossover behavior from the Ginibre ensemble to the Poisson ensemble first appears close to the surface of the spectrum. Our model may be relevant for the description of the spectral correlations of an open disordered system close to an Anderson transition.Comment: 25 pages, 6 figure

    The value of nonlinear control theory in investigating the underlying dynamics and resilience of a grocery supply chain

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    In an empirical context, a method to use nonlinear control theory in the dynamic analysis of supply chain resilience is developed and tested. The method utilises block diagram development, transfer function formulation, describing function representation of nonlinearities and simulation. Using both ‘shock’ or step response and ‘filter’ or frequency response lenses, a system dynamics model is created to analyse the resilience performance of a distribution centre replenishment system at a large grocery retailer. Potential risks for the retailer’s resilience performance include the possibility of a mismatch between supply and demand, as well as serving the store inefficiently and causing on-shelf stock-outs. Thus, resilience is determined by investigating the dynamic behaviour of stock and shipment responses. The method allows insights into the nonlinear system control structures that would not be evident using simulation alone, including a better understanding of the influence of control parameters on dynamic behaviour, the identification of inventory offsets potentially leading to ‘drift’, the impact of nonlinearities on supply chain performance and the minimisation of simulation experiments

    Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds

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    Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period
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