474 research outputs found

    The internal magnetic field in superconducting ferromagnets

    Full text link
    We have measured the nonlinear response to the ac magnetic field in the superconducting weak ferromagnet Ru-1222, at different regimes of sample cooling which provides unambiguous evidence of the interplay of the domain structure and the vorticity in the superconducting state. This is {\em direct} proof of coexistence of ferromagnetic and superconductive order parameters in high-TcT_c ruthenocuprates.Comment: 9 pages, 6 figure

    Pseudo-Foster Kennedy Syndrome due to unilateral optic nerve hypoplasia: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Pseudo-Foster Kennedy Syndrome is described as unilateral optic disc swelling with contralateral optic atrophy in the absence of an intracranial mass causing compression of the optic nerve. This occurs typically due to bilateral sequential optic neuritis or ischaemic optic neuropathy.</p> <p>Case Presentation</p> <p>We describe a case of pseudo-Foster Kennedy Syndrome in a two year old boy with unilateral papilloedema due to a congenital optic disc anomaly in one eye preventing transmission of raised intracranial pressure to the optic nerve.</p> <p>Conclusion</p> <p>From our findings we conclude that congenital optic nerve hypoplasia is a cause of pseudo-Foster Kennedy Syndrome.</p

    Stratifying quotient stacks and moduli stacks

    Full text link
    Recent results in geometric invariant theory (GIT) for non-reductive linear algebraic group actions allow us to stratify quotient stacks of the form [X/H], where X is a projective scheme and H is a linear algebraic group with internally graded unipotent radical acting linearly on X, in such a way that each stratum [S/H] has a geometric quotient S/H. This leads to stratifications of moduli stacks (for example, sheaves over a projective scheme) such that each stratum has a coarse moduli space.Comment: 25 pages, submitted to the Proceedings of the Abel Symposium 201

    Reaping the Benefits and Avoiding the Risks: Unrealistic Optimism in the Health Domain.

    Get PDF
    People's perceptions of benefits and risks play a key role in their acceptance or rejection of medical interventions, yet these perceptions may be poorly calibrated. This online study with N = 373 adults aged 19-76 years focused on unrealistic optimism in the health domain. Participants indicated how likely they were to experience benefits and risks associated with medical conditions and completed objective and subjective numeracy scales. Participants exhibited optimistic views about the likelihood of experiencing the benefits and the side effects of treatment options described in the scenarios. Objective and subjective numeracy were not associated with more accurate ratings. Moreover, participants' underestimation of the risks was significantly greater than their overestimation of the benefits. From an applied perspective, these results suggest that clinicians may need to ensure that patients do not underestimate risks of medical interventions, and that they convey realistic expectations about the benefits that can be obtained with certain procedures

    Applications of patching to quadratic forms and central simple algebras

    Full text link
    This paper provides applications of patching to quadratic forms and central simple algebras over function fields of curves over henselian valued fields. In particular, we use a patching approach to reprove and generalize a recent result of Parimala and Suresh on the u-invariant of p-adic function fields, for p odd. The strategy relies on a local-global principle for homogeneous spaces for rational algebraic groups, combined with local computations.Comment: 48 pages; connectivity now required in the definition of rational group; beginning of Section 4 reorganized; other minor change

    Diagnosis and Management of Esophageal Injuries: A Western Trauma Association Critical Decisions Algorithm

    Get PDF
    ABSTRACT: This is a recommended management algorithm from the Western Trauma Association addressing the diagnostic evaluation and management of esophageal injuries in adult patients. Because there is a paucity of published prospective randomized clinical trials that have generated Class I data, the recommendations herein are based primarily on published observational studies and expert opinion of Western Trauma Association members. The algorithms and accompanying comments represent a safe and sensible approach that can be followed at most trauma centers. We recognize that there will be patient, personnel, institutional, and situational factors that may warrant or require deviation from the recommended algorithm. We encourage institutions to use this guideline to formulate their own local protocols. The algorithm contains letters at decision points; the corresponding paragraphs in the text elaborate on the thought process and cite pertinent literature. The annotated algorithm is intended to (a) serve as a quick bedside reference for clinicians; (b) foster more detailed patient care protocols that will allow for prospective data collection and analysis to identify best practices; and (c) generate research projects to answer specific questions concerning decision making in the management of adults with esophageal injuries

    Measures on Banach Manifolds and Supersymmetric Quantum Field Theory

    Full text link
    We show how to construct measures on Banach manifolds associated to supersymmetric quantum field theories. These measures are mathematically well-defined objects inspired by the formal path integrals appearing in the physics literature on quantum field theory. We give three concrete examples of our construction. The first example is a family μPs,t\mu_P^{s,t} of measures on a space of functions on the two-torus, parametrized by a polynomial PP (the Wess-Zumino-Landau-Ginzburg model). The second is a family \mu_\cG^{s,t} of measures on a space \cG of maps from 1\P^1 to a Lie group (the Wess-Zumino-Novikov-Witten model). Finally we study a family μM,Gs,t\mu_{M,G}^{s,t} of measures on the product of a space of connection s on the trivial principal bundle with structure group GG on a three-dimensional manifold MM with a space of \fg-valued three-forms on M.M. We show that these measures are positive, and that the measures \mu_\cG^{s,t} are Borel probability measures. As an application we show that formulas arising from expectations in the measures \mu_\cG^{s,1} reproduce formulas discovered by Frenkel and Zhu in the theory of vertex operator algebras. We conjecture that a similar computation for the measures μM,SU(2)s,t,\mu_{M,SU(2)}^{s,t}, where MM is a homology three-sphere, will yield the Casson invariant of M.M.Comment: Minor correction

    Principles for language tests within the 'discourse domains' theory of interlanguage: research, test construction and interpretation

    Full text link
    This article considers an alternative framework for handling the language testing enterprise and proposes some tentative theoretical hypotheses concerning principles of language testing. It is the writers' view that taking account of the perspective of interlanguage domain engagement and contextualization in testing research, production and interpretation allows for a richer conceptualization of the language testing process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69012/2/10.1177_026553228500200208.pd

    Coordinated optimization of visual cortical maps (I) Symmetry-based analysis

    Get PDF
    In the primary visual cortex of primates and carnivores, functional architecture can be characterized by maps of various stimulus features such as orientation preference (OP), ocular dominance (OD), and spatial frequency. It is a long-standing question in theoretical neuroscience whether the observed maps should be interpreted as optima of a specific energy functional that summarizes the design principles of cortical functional architecture. A rigorous evaluation of this optimization hypothesis is particularly demanded by recent evidence that the functional architecture of OP columns precisely follows species invariant quantitative laws. Because it would be desirable to infer the form of such an optimization principle from the biological data, the optimization approach to explain cortical functional architecture raises the following questions: i) What are the genuine ground states of candidate energy functionals and how can they be calculated with precision and rigor? ii) How do differences in candidate optimization principles impact on the predicted map structure and conversely what can be learned about an hypothetical underlying optimization principle from observations on map structure? iii) Is there a way to analyze the coordinated organization of cortical maps predicted by optimization principles in general? To answer these questions we developed a general dynamical systems approach to the combined optimization of visual cortical maps of OP and another scalar feature such as OD or spatial frequency preference.Comment: 90 pages, 16 figure
    corecore