1,398 research outputs found

    Regulator constants and the parity conjecture

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    The p-parity conjecture for twists of elliptic curves relates multiplicities of Artin representations in p-infinity Selmer groups to root numbers. In this paper we prove this conjecture for a class of such twists. For example, if E/Q is semistable at 2 and 3, K/Q is abelian and K^\infty is its maximal pro-p extension, then the p-parity conjecture holds for twists of E by all orthogonal Artin representations of Gal(K^\infty/Q). We also give analogous results when K/Q is non-abelian, the base field is not Q and E is replaced by an abelian variety. The heart of the paper is a study of relations between permutation representations of finite groups, their "regulator constants", and compatibility between local root numbers and local Tamagawa numbers of abelian varieties in such relations.Comment: 50 pages; minor corrections; final version, to appear in Invent. Mat

    Predictors of entering a hearing aid evaluation period: a prospective study in older hearing-help seekers

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    This study aimed to determine the predictors of entering a hearing aid evaluation period (HAEP) using a prospective design drawing on the health belief model and the transtheoretical model. In total, 377 older persons who presented with hearing problems to an ENT-specialist (n = 110) or a hearing aid dispenser (n = 267) filled in a baseline questionnaire. After four months, it was determined via a telephone interview whether or not participants had decided to enter a HAEP. Multivariable logistic regression analyses were applied to determine which baseline variables predicted HAEP status. A priori, candidate predictors were divided into ‘likely’ and ‘novel’ predictors based on the literature. The following variables turned out to be significant predictors: more expected hearing aid benefits, greater social pressure, and greater self-reported hearing disability. In addition, greater hearing loss severity and stigma were predictors in women but not in men. Of note, the predictive effect of self-reported hearing disability was modified by readiness such that with higher readiness, the positive predictive effect became stronger. None of the ‘novel’ predictors added significant predictive value. The results support the notion that predictors of hearing aid uptake are also predictive of entering a HAEP. This study shows that some of these predictors appear to be gender-specific or are dependent on a person’s readiness for change. After assuring the external validity of the predictors, an important next step would be to develop prediction rules for use in clinical practice, so that older persons’ hearing help seeking journey can be facilitated

    Theoretical Aspects of τKh(h)ντ\tau \to K h (h) \nu_\tau Decays and Experimental Comparisons

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    Predictions for decay rates and distributions for τ\tau decays into final states with kaons are discussed and compared with recent measurements. Special emphasis is put on new constraints for the vector current contribution in the KKπKK\pi decay modes. For the KππK\pi\pi modes, disagreements with the experimental results can be traced back to the K1K_1 widths.Comment: 11 pages, 8 Figures, Latex, uses twoside, fleqn, espcrc2 style files. Talk presented by Erwin Mirkes at the Fourth International Workshp on Tau Lepton Physics (TAU 96), 16--19 September 1996, Estes Park, Colorado, US

    Verkenning van de rol van (openbaar) groen op wijk- en buurtniveau op het hitte-eilandeffect

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    Dit werkdocument gaat in op de effecten van (openbaar) groen op het Urban Heat Island Effect (UHI). Voor vijftien wijken in Rotterdam is een relatie gelegd tussen het bedekkingspercentage van verschillende hoogteklassen groen en de grootte van het UHI-effect. Er worden hierbij grote verschillen tussen de wijken gevonden. Voorts is voor drie buurten in beeld gebracht welke effecten het opgaande groen heeft op de hoeveelheid zonne-instraling die het straatniveau bereikt. Deze laatste bepaalt het comfort op straatniveau gedurende de dag

    Social determinants of content selection in the age of (mis)information

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    Despite the enthusiastic rhetoric about the so called \emph{collective intelligence}, conspiracy theories -- e.g. global warming induced by chemtrails or the link between vaccines and autism -- find on the Web a natural medium for their dissemination. Users preferentially consume information according to their system of beliefs and the strife within users of opposite narratives may result in heated debates. In this work we provide a genuine example of information consumption from a sample of 1.2 million of Facebook Italian users. We show by means of a thorough quantitative analysis that information supporting different worldviews -- i.e. scientific and conspiracist news -- are consumed in a comparable way by their respective users. Moreover, we measure the effect of the exposure to 4709 evidently false information (satirical version of conspiracy theses) and to 4502 debunking memes (information aiming at contrasting unsubstantiated rumors) of the most polarized users of conspiracy claims. We find that either contrasting or teasing consumers of conspiracy narratives increases their probability to interact again with unsubstantiated rumors.Comment: misinformation, collective narratives, crowd dynamics, information spreadin

    Brane World Susy Breaking from String/M Theory

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    String and M-theory realizations of brane world supersymmetry breaking scenarios are considered in which visible sector Standard Model fields are confined on a brane, with hidden sector supersymmetry breaking isolated on a distant brane. In calculable examples with an internal manifold of any volume the Kahler potential generically contains brane--brane non-derivative contact interactions coupling the visible and hidden sectors and is not of the no-scale sequestered form. This leads to non-universal scalar masses and without additional assumptions about flavor symmetries may in general induce dangerous sflavor violation even though the Standard Model and supersymmetry branes are physically separated. Deviations from the sequestered form are dictated by bulk supersymmetry and can in most cases be understood as arising from exchange of bulk supergravity fields between branes or warping of the internal geometry. Unacceptable visible sector tree-level tachyons arise in many models but may be avoided in certain classes of compactifications. Anomaly mediated and gaugino mediated contributions to scalar masses are sub-dominant except in special circumstances such as a flat or AdS pure five--dimensional bulk geometry without bulk vector multiplets.Comment: Latex, 83 pages, references adde

    Next-to-Next-to-Leading Logarithms in Four-Fermion Electroweak Processes at High Energy

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    We sum up the next-to-next-to-leading logarithmic virtual electroweak corrections to the high energy asymptotics of the neutral current four-fermion processes for light fermions to all orders in the coupling constants using the evolution equation approach. From this all order result we derive finite order expressions through next-to-next-to leading order for the total cross section and various asymmetries. We observe an amazing cancellation between the sizable leading, next-to-leading and next-to-next-to-leading logarithmic contributions at TeV energies.Comment: latex, 20 pages; coupling constant in the fermionic contribution to the electroweak corrections correcte

    Pulsar Timing and its Application for Navigation and Gravitational Wave Detection

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    Pulsars are natural cosmic clocks. On long timescales they rival the precision of terrestrial atomic clocks. Using a technique called pulsar timing, the exact measurement of pulse arrival times allows a number of applications, ranging from testing theories of gravity to detecting gravitational waves. Also an external reference system suitable for autonomous space navigation can be defined by pulsars, using them as natural navigation beacons, not unlike the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location (e.g. the solar system barycenter), the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. We describe the unique properties of pulsars that suggest that such a navigation system will certainly have its application in future astronautics. We also describe the on-going experiments to use the clock-like nature of pulsars to "construct" a galactic-sized gravitational wave detector for low-frequency (f_GW ~1E-9 - 1E-7 Hz) gravitational waves. We present the current status and provide an outlook for the future.Comment: 30 pages, 9 figures. To appear in Vol 63: High Performance Clocks, Springer Space Science Review

    Vortex structure in chiral p-wave superconductors

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    We investigate the vortex structure in chiral p-wave superconductors by the Bogoliubov-de Gennes theory on a tight-binding model. We calculate the spatial structure of the pair potential and electronic state around a vortex, including the anisotropy of the Fermi surface and superconducting gap structure. The differences of the vortex structure between sinpx+isinpy\sin p_x + {\rm i} \sin p_y-wave and sinpxisinpy \sin p_x - {\rm i} \sin p_y-wave superconductors are clarified in the vortex lattice state. We also discuss the winding 3\mp 3 case of the sin(px+py)±isin(px+py)\sin{(p_x+p_y)} \pm {\rm i} \sin{(-p_x+p_y)}-wave superconductivity.Comment: 10 pages, 8 figure
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