5,751 research outputs found

    In the wake of the erbium-doped fiber amplifier - functional fibers and their impact

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    There have been a number of laser developments in recent years that are quite staggering in their simplicity, that are so powerful in their operation that engineers and scientist have to rethink the laser future. One such is the high power fibre laser, born out of the optical telecoms revolution. It challenges currently held views on how to make things, how to repair things, and how to destroy things. With small size, maintenance-free operation, high thermal and electrical efficiency and outstanding beam quality, it has the potential to change every industry and discipline it encounters

    Fibre lasers: the new wave in material processing

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    In the last few years, fibre lasers have established themselves as the preferred laser source in many applications. The combination of small size, maintenance-free operation, thermal and electrical efficiency combined with outstanding (diffraction-limited) beam quality have made the fibre laser an attractive alternative to more established technologies. In fact, in some processes the fiber laser is the enabling technology. Unique among high power lasers, the fiber laser is monolithic, the light being entirely confined to the fiber core. This gives immunity to thermal distortion of the beam, almost instant startup, very high stability and protection from the environment. Maintenance is minimal, since no realignment or cleaning of components is necessary

    Releasing the Power of Digital Metadata: Examining Large Networks of Co-Related Publications

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    Bibliographic metadata plays a key role in scientific literature, not only to summarise and establish the facts of the publication record, but also to track citations between publications and hence to establish the impact of individual articles within the literature. Commercial secondary publishers have typically taken on the role of rekeying, mining and analysing this huge corpus of linked data, but as the primary literature has moved to the world of the digital repository, this task is now undertaken by new services such as Citeseer, Citebase or Google Scholar. As institutional and subject-based repositories proliferate and Open Access mandates increase, more of the literature will become openly available in well managed data islands containing a much greater amount of detailed bibliometric metadata in formats such as RDF. Through the use of efficient extraction and inference techniques, complex relations between data items can be established. In this paper we explain the importance of the co-relation in enabling new techniques to rate the impact of a paper or author within a large corpus of publications

    Personal constructs of mind-body identity in people who experience medically unexplained symptoms (MUS)

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    "Medically unexplained symptoms" (MUS) refers to chronic physical symptoms without a clear medical cause, which produce significant levels of distress and functional impairment. This project modified the repertory grid technique to explore how twenty participants experiencing MUS construed self and others in bodily and psychological ways. Findings suggested that symptoms are well integrated within participants' wider mind–body construct systems. Increased distance between how self in general is construed compared to self when symptoms are worst was associated with reduced anxiety. Measuring intrapersonal and interpersonal implicative dilemmas suggested that moral and relational construing of identity is affected by MUS.Peer reviewe

    The Kodaira dimensions of M22\overline{\mathcal{M}}_{22} and M23\overline{\mathcal{M}}_{23}

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    We prove that the moduli spaces of curves of genus 22 and 23 are of general type. To do this, we calculate certain virtual divisor classes of small slope associated to linear series of rank 6 with quadric relations. We then develop new tropical methods for studying linear series and independence of quadrics and show that these virtual classes are represented by effective divisors.Comment: 94 pages, 27 figures; incorporates and supersedes arXiv:1804.01898 and arXiv:1808.0128

    On the general position subset selection problem

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    Let f(n,)f(n,\ell) be the maximum integer such that every set of nn points in the plane with at most \ell collinear contains a subset of f(n,)f(n,\ell) points with no three collinear. First we prove that if O(n)\ell \leq O(\sqrt{n}) then f(n,)Ω(nln)f(n,\ell)\geq \Omega(\sqrt{\frac{n}{\ln \ell}}). Second we prove that if O(n(1ϵ)/2)\ell \leq O(n^{(1-\epsilon)/2}) then f(n,)Ω(nlogn)f(n,\ell) \geq \Omega(\sqrt{n\log_\ell n}), which implies all previously known lower bounds on f(n,)f(n,\ell) and improves them when \ell is not fixed. A more general problem is to consider subsets with at most kk collinear points in a point set with at most \ell collinear. We also prove analogous results in this setting