913 research outputs found

    Legendrian and transverse cables of positive torus knots

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    In this paper we classify Legendrian and transverse knots in the knot types obtained from positive torus knots by cabling. This classification allows us to demonstrate several new phenomena. Specifically, we show there are knot types that have non-destabilizable Legendrian representatives whose Thurston-Bennequin invariant is arbitrarily far from maximal. We also exhibit Legendrian knots requiring arbitrarily many stabilizations before they become Legendrian isotopic. Similar new phenomena are observed for transverse knots. To achieve these results we define and study "partially thickenable" tori, which allow us to completely classify solid tori representing positive torus knots.Comment: 34 pages, 6 figure

    Graph run-length matrices for histopathological image segmentation

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    Cataloged from PDF version of article.The histopathological examination of tissue specimens is essential for cancer diagnosis and grading. However, this examination is subject to a considerable amount of observer variability as it mainly relies on visual interpretation of pathologists. To alleviate this problem, it is very important to develop computational quantitative tools, for which image segmentation constitutes the core step. In this paper, we introduce an effective and robust algorithm for the segmentation of histopathological tissue images. This algorithm incorporates the background knowledge of the tissue organization into segmentation. For this purpose, it quantifies spatial relations of cytological tissue components by constructing a graph and uses this graph to define new texture features for image segmentation. This new texture definition makes use of the idea of gray-level run-length matrices. However, it considers the runs of cytological components on a graph to form a matrix, instead of considering the runs of pixel intensities. Working with colon tissue images, our experiments demonstrate that the texture features extracted from "graph run-length matrices" lead to high segmentation accuracies, also providing a reasonable number of segmented regions. Compared with four other segmentation algorithms, the results show that the proposed algorithm is more effective in histopathological image segmentatio

    Over-reaction and under-reaction in climate policy: an institutional analysis

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    In what circumstances do organizations react to changes in their operating environment by adopting proportionate policy responses? And drawing on institutional theory, what expectations can we formulate in relation to the proportionality of policy responses to climate change? These two research questions frame this article, which seeks to make new connections between the emerging perspective of proportionality in policy-making and existing institutional theories. We find that institutional theories are well suited to formulating expectations concerning the (dis)proportionality of policy responses, but their explanatory power can be further improved by taking the characteristics of specific climate policy problems into account. While there are many different problems nested in the ‘meta’ problem of climate change, we find that most of them have characteristics which suggest that policy under-reactions are more, not less likely. Amongst institutional theories, rational choice institutionalism provides the clearest expectation that proportionate policy responses are unlikely. Policy entrepreneurship is identified as one obvious way in which to stimulate proportionate policy responses, through fostering new ways of thinking within organizations

    Proportionate and disproportionate policy responses to climate change: core concepts and empirical applications

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    A fresh perspective on policy-making and planning has emerged which views disproportionate policy as an intentional policy response. A disproportionate policy response is understood to be a lack of‘fit’or balance between the costs of a public policy and the benefits that are derived from this policy, and between policy ends and means. This paper applies this new perspective on the proportionality of policy-making to the area of climate change. The first part of the paper discusses the underlying causes of disproportionate policy responses in broad terms and then applies the theoretical reasoning to understand the conditions in which they are likely to appear in relation to climate change. These conditions are hypothesized to relate to four main factors: economic considerations; levels of public demand; focusing events; and strategic considerations. It concludes with the suggestion that societal actors may be able to manipulate these four factors to encourage politicians to adopt policies that mitigate climate change more rapidly than is currently the case in most countries

    Grain rotation and lattice deformation during perovskite spray coating and annealing probed in situ by GI-WAXS

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    We report for the first time on grain rotation in CH3NH3PbI3 perovskite films for ∼12% efficient planar solar cells and present a new method for investigating their texture evolution during thermal annealing. Our technique is based on in situ 2D grazing incidence wide-angle X-ray scattering (GI-WAXS) and employs a 10 keV wide-focussed X-ray beam to simultaneously probe a large number of grains. The ability to track the texture dynamics from a statistically relevant number of spots diffracting from single grains during thermal annealing and in grazing incidence geometry can have applications understanding the processing dynamics of a range of new materials

    The Development of an Argon Light Source for Calibration and Quality Control of Liquid Argon Light Detectors

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    2022 IEEE Nuclear Science Symposium, Medical Imaging Conference, and Room Temperature Semiconductor Detector Conference, IEEE NSS MIC RTSD 2022 -- 5 November 2022 through 12 November 2022 -- -- 196914Future large-scale neutrino and dark matter experiments will mostly use liquid argon detectors. Since liquid argon is a very effective scintillator, light sensing systems are included in these experiments. The wavelength of liquid argon scintillation is 127 nm. For this reason special light detectors based on wavelength shifters have been produced to measure this wavelength, and recently photodetectors sensitive to deeper UV. Nonetheless, the effective calibration and quality assurance of these recently developed detectors remain an ongoing challenge. In response to this requirement, we have created an argon-based light source that relies on plasma generation and light transmission via an MgF2 window. This light source is designed to be compact, portable, and user-friendly, allowing for the practical evaluation of the performance attributes of light detectors of several square meters in size. In this report, we detail the progression of the light source's development and outline its performance attributes. © 2022 IEEE.This work is supported by Tübitak grant no 118C224

    Structural and magnetic properties of Co-V nanoparticles

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    We have investigated the structural and magnetic properties of Co1-xVx nanoparticles (NPs) with composition x = 0.25 (stoichiometric) and 0.29 (under-stoichiometric) prepared by the cluster-beam deposition (CBD) technique. Our data shows that the as-made Co1-xVx NPs are a mixture of the high-temperature phase (HTP) and the low-temperature phase (LTP) of Co3V and the particles are superparamagnetic at room temperature (RT) with blocking temperatures (TB) of 90 and 137 K for x = 0.25 and 0.29, respectively. This behavior contrasts with the bulk which are paramagnetic down to 4.2 K. When the Co75V25 NPs are annealed at 573 K, they undergo a phase separation into a mixture of phases and become ferromagnetic at room temperature with Curie temperature (Tc) of 515 K

    High-Tech Augmentative and Alternative Communication for Individuals with IDD and Complex Communication Needs: A Meta-Analysis (Search Terms)

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    Search Terms used in this manuscriptSearch Terms attached for the following paper: The use of mobile technology is ubiquitous and is rapidly increasing in novel use. The use of mobile apps as augmentative and alternative communication (AAC) is rapidly expanding, both in the community and in the research literature. This article reports the social-communication outcome results of a meta-analysis of single-case experimental research on the use of high-tech AAC with individuals with intellectual and developmental disabilities, including autism spectrum disorder. Following inclusion determination, including excluding studies with poor design quality, raw data from 24 publications were extracted and included 89 A-B phase contrasts. Tau-U nonparametric, non-overlap effect size was used to aggregate the results across all studies for an omnibus and moderator analyses. Kendall’s S was calculated for confidence intervals, p-values, and standard error. The omnibus analysis indicated overall low to moderate positive effects on social-communication outcomes for high-tech AAC with people with IDD.The contents of this manuscript were developed under the Preparation of Leaders in Autism Across the Lifespan grant awarded by the U.S. Department of Education, Office of Special Education Programs (Grant No. H325D110046)
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