1,809 research outputs found

    The central limit problem for random vectors with symmetries

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    Motivated by the central limit problem for convex bodies, we study normal approximation of linear functionals of high-dimensional random vectors with various types of symmetries. In particular, we obtain results for distributions which are coordinatewise symmetric, uniform in a regular simplex, or spherically symmetric. Our proofs are based on Stein's method of exchangeable pairs; as far as we know, this approach has not previously been used in convex geometry and we give a brief introduction to the classical method. The spherically symmetric case is treated by a variation of Stein's method which is adapted for continuous symmetries.Comment: AMS-LaTeX, uses xy-pic, 23 pages; v3: added new corollary to Theorem

    Sub-wavelength surface IR imaging of soft-condensed matter

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    Outlined here is a technique for sub-wavelength infrared surface imaging performed using a phase matched optical parametric oscillator laser and an atomic force microscope as the detection mechanism. The technique uses a novel surface excitation illumination approach to perform simultaneously chemical mapping and AFM topography imaging with an image resolution of 200 nm. This method was demonstrated by imaging polystyrene micro-structures

    Excretory/Secretory-Products of Echinococcus multilocularis Larvae Induce Apoptosis and Tolerogenic Properties in Dendritic Cells In Vitro

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    Parasitic helminths are inducers of chronic diseases and have evolved mechanisms to suppress the host immune response. Mostly from studies on roundworms, a picture is currently emerging that helminths secrete factors (E/S-products) that directly act on sentinels of the immune system, dendritic cells, in order to achieve an expansion of immunosuppressive, regulatory T cells (T-reg). Parasitic helminths are currently also intensely studied as therapeutic agents against autoimmune diseases and allergies, which is directly linked to their immunosuppressive activities. The immunomodulatory products of parasitic helminths are therefore of high interest for understanding immunopathology during infections and for the treatment of allergies. The present work was conducted on larvae of the tapeworm E. multilocularis, which grow like a tumor into surrounding host tissue and thus cause the lethal disease alveolar echinococcosis. The authors found that E/S-products from early infective larvae are strong inducers of tolerogenic DC in vitro and show that E/S-products of larvae of the chronic stage lead to an in vitro expansion of Foxp3+ T cells, suggesting that both the expansion of these T cells and poorly responsive DC are important for the establishment and persistence of E. multilocularis larvae within the host

    Now or never: perceptions of uniqueness induce acceptance of price increases for experiences more than for objects

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    Seven studies test and support the prediction that consumers are more willing to accept a price increase for an experiential versus a material purchase; an effect explained by the greater uniqueness of experiences. Critically, the uniqueness model advanced here is found to be independent of the happiness consumers derive from the purchase. To gain a deeper understanding of the uniqueness mechanism, this investigation then advances and tests a four-facet framework of uniqueness (unique opportunity, unique purchase, unique identity, and counterconformity). Together, the findings converge on the conclusion that consumers perceive the opportunity to have a particular experience (vs. object) as more unique, and this unique opportunity increases their willingness to accept a price increase. Overall, this work extends the experiential versus material purchases literature into a new domain—that of pricing; identifies the dimension—uniqueness—and its precise facet responsible for the effect—unique opportunity; and demonstrates that this model unfolds in a pattern distinct from the oft researched model centered on consumer happiness. Theoretical and practical implications are discussed.info:eu-repo/semantics/acceptedVersio

    Effects of mesenchymal stromal cells versus serum on tendon healing in a controlled experimental trial in an equine model

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    Abstract Background Mesenchymal stromal cells (MSC) have shown promising results in the treatment of tendinopathy in equine medicine, making this therapeutic approach seem favorable for translation to human medicine. Having demonstrated that MSC engraft within the tendon lesions after local injection in an equine model, we hypothesized that they would improve tendon healing superior to serum injection alone. Methods Quadrilateral tendon lesions were induced in six horses by mechanical tissue disruption combined with collagenase application 3 weeks before treatment. Adipose-derived MSC suspended in serum or serum alone were then injected intralesionally. Clinical examinations, ultrasound and magnetic resonance imaging were performed over 24 weeks. Tendon biopsies for histological assessment were taken from the hindlimbs 3 weeks after treatment. Horses were sacrificed after 24 weeks and forelimb tendons were subjected to macroscopic and histological examination as well as analysis of musculoskeletal marker expression. Results Tendons injected with MSC showed a transient increase in inflammation and lesion size, as indicated by clinical and imaging parameters between week 3 and 6 (p < 0.05). Thereafter, symptoms decreased in both groups and, except that in MSC-treated tendons, mean lesion signal intensity as seen in T2w magnetic resonance imaging and cellularity as seen in the histology (p < 0.05) were lower, no major differences could be found at week 24. Conclusions These data suggest that MSC have influenced the inflammatory reaction in a way not described in tendinopathy studies before. However, at the endpoint of the current study, 24 weeks after treatment, no distinct improvement was observed in MSC-treated tendons compared to the serum-injected controls. Future studies are necessary to elucidate whether and under which conditions MSC are beneficial for tendon healing before translation into human medicine

    Dependence of paracentric inversion rate on tract length

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    BACKGROUND: We develop a Bayesian method based on MCMC for estimating the relative rates of pericentric and paracentric inversions from marker data from two species. The method also allows estimation of the distribution of inversion tract lengths. RESULTS: We apply the method to data from Drosophila melanogaster and D. yakuba. We find that pericentric inversions occur at a much lower rate compared to paracentric inversions. The average paracentric inversion tract length is approx. 4.8 Mb with small inversions being more frequent than large inversions. If the two breakpoints defining a paracentric inversion tract are uniformly and independently distributed over chromosome arms there will be more short tract-length inversions than long; we find an even greater preponderance of short tract lengths than this would predict. Thus there appears to be a correlation between the positions of breakpoints which favors shorter tract lengths. CONCLUSION: The method developed in this paper provides the first statistical estimator for estimating the distribution of inversion tract lengths from marker data. Application of this method for a number of data sets may help elucidate the relationship between the length of an inversion and the chance that it will get accepted

    Predictors of Acceptance and Rejection of Online Peer Support Groups as a Digital Wellbeing Tool

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    © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG. Digital media usage can be problematic; exhibiting symptoms of behavioural addiction such as mood modification, tolerance, conflict, salience, withdrawal symptoms and relapse. Google Digital Wellbeing and Apple Screen Time are examples of an emerging family of tools to help people have a healthier and more conscious relationship with technology. Peer support groups is a known technique for behaviour change and relapse prevention. It can be facilitated online, especially with advanced social networking techniques. Elements of peer support groups are being already embedded in digital wellbeing tools, e.g. peer comparisons, peer commitments, collective usage limit-setting and family time. However, there is a lack of research about the factors influencing people acceptance and rejection of online peer support groups to enhance digital wellbeing. Previous work has qualitatively explored the acceptance and rejection factors to join and participate in such groups. In this paper, we quantitatively study the relationship between culture, personality, self-control, gender, willingness to join the groups and perception of their usefulness, on such acceptance and rejection factors. The qualitative phase included two focus groups and 16 interviews while the quantitative phase consisted of a survey (215 participants). We found a greater number of significant models to predict rejection factors than acceptance factors, although in all cases the amount of variance explained by the models was relatively small. This demonstrates the need to design and, also, introduce such technique in a contextualised and personalised style to avoid rejection and reactance
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