955 research outputs found

    Cooperative localization-delocalization in the high Tc cuprates

    Full text link
    The intrinsic metastable crystal structure of the cuprates results in local dynamical lattice instabilities, strongly coupled to the density fluctuations of the charge carriers. They acquire in this way simultaneously both, delocalized and localized features. It is responsible for a partial fractioning of the Fermi surface, i.e., the Fermi surface gets hidden in a region around the anti-nodal points, because of the opening of a pseudogap in the normal state, arising from a partial charge localization. The high energy localized single-particle features are a result of a segregation of the homogeneous crystal structure into checker-board local nano-size structures, which breaks the local translational and rotational symmetry. The pairing in such a system is dynamical rather than static, whereby charge carriers get momentarily trapped into pairs in a deformable dynamically fluctuating ligand environment. We conclude that the intrinsically heterogeneous structure of the cuprates must play an important role in this type of superconductivity.Comment: 14 pages, 8 figures, Proceedings of the "International Conference on Condensed Matter Theories", Quito, 2009 Int. J. Mod. Phys. B 2010 (Accepted

    Enhancing dysphonia clinic consultations through a focus on patients' expectations : streamlining and validation of a new tool (ACaPELa-R questionnaire)

    Get PDF
    ObjectiveThe Assessing and Caring for Patients' Expectations in Laryngology ('ACaPELa') questionnaire was developed to guide laryngology clinic consultations. This study aimed to audit its use, revise it depending on outcomes and validate it.MethodsThe questionnaire was completed by all new patients attending a laryngology clinic over one year. The questionnaire was refined and validated in a new cohort of patients over a six-month period.ResultsThirty-seven of 242 patients (15.3 per cent) incorrectly gave the same ranking to more than one question. Questions with similar content were collapsed to cover broader themes, and an outcome question was added, resulting in the five-item Assessing and Caring for Patients' Expectations in Laryngology - Revised ('ACaPELa-R') questionnaire. Using this revised questionnaire, there was a significant reduction in the number of same-ranked questions (4.4 vs 15.3 per cent; p = 0.003) and high patient satisfaction post-consultation (95.7 per cent).ConclusionThe Assessing and Caring for Patients' Expectations in Laryngology - Revised questionnaire makes patients' rank ordering of questions easier. It can be used to inform how different topics should be approached during the consultation and utilised for clinician self-audit

    Secondary literacy across the curriculum: Challenges and possibilities

    Get PDF
    This paper discusses the challenges and possibilities attendant upon successfully implementing literacy across the curriculum initiatives – or ‘school language policies’ as they have come to be known - particularly at the secondary or high school level. It provides a theoretical background to these issues, exploring previous academic discussions of school language policies, and highlights key areas of concern as well as opportunity with respect to school implementation of such policies. As such, it provides a necessary conceptual background to the subsequent papers in this special issue, which focus upon the Secondary Schools’ Literacy Initiative (SSLI) – a New Zealand funded programme that aims to establish cross-curricular language and literacy policies in secondary schools

    Deformation of a nearly hemispherical conducting drop due to an electric field: theory and experiment

    Get PDF
    We consider, both theoretically and experimentally, the deformation due to an electric field of a pinned nearly-hemispherical static sessile drop of an ionic fluid with a high conductivity resting on the lower substrate of a parallel plate capacitor. Using both numerical and asymptotic approaches we find solutions to the coupled electrostatic and augmented Young–Laplace equations which agree very well with the experimental results. Our asymptotic solution for the drop interface extends previous work in two ways, namely to drops that have zero-field contact angles that are not exactly π/2 and to higher order in the applied electric field, and provides useful predictive equations for the changes in the height, contact angle and pressure as functions of the zero-field contact angle, drop radius, surface tension and applied electric field. The asymptotic solution requires some numerical computations, and so a surprisingly accurate approximate analytical asymptotic solution is also obtained

    Clinical applicability and revision of the ACaPELa questionnaire

    Get PDF
    The Assessing and Caring for Patients’ Expectations in Laryngology (ACaPELa) questionnaire was created to understand patients’ thoughts and concerns and guide clinical consultation. As part of our standard clinical practice, all patients attending the laryngology clinic in our department complete the ACaPELa, rank ordering their expectations prior to the clinical consultation. Feedback received from the patients during the 2-year run of the voice clinic using the above set-up has indicated that the questionnaire was proven difficult to rank order, with patients’ finding some of the options very similar in content

    Possible Pseudogap Phase in QCD

    Get PDF
    Thermal pion fluctuations, in principle, can completely disorder the phase of the quark condensate and thus restore chiral symmetry. If this happens before the quark condensate melts, strongly-interacting matter will be in the pseudogap state just above the chiral phase transition. The quark condensate does not vanish locally and quarks acquire constituent masses in the pseudogap phase, despite chiral symmetry is restored.Comment: 8 pages, 1 figure; v2: references added; v3: argumerts modified; v4: minor changes; v5: a misprint correcte

    Quantifying loopy network architectures

    Get PDF
    Biology presents many examples of planar distribution and structural networks having dense sets of closed loops. An archetype of this form of network organization is the vasculature of dicotyledonous leaves, which showcases a hierarchically-nested architecture containing closed loops at many different levels. Although a number of methods have been proposed to measure aspects of the structure of such networks, a robust metric to quantify their hierarchical organization is still lacking. We present an algorithmic framework, the hierarchical loop decomposition, that allows mapping loopy networks to binary trees, preserving in the connectivity of the trees the architecture of the original graph. We apply this framework to investigate computer generated graphs, such as artificial models and optimal distribution networks, as well as natural graphs extracted from digitized images of dicotyledonous leaves and vasculature of rat cerebral neocortex. We calculate various metrics based on the Asymmetry, the cumulative size distribution and the Strahler bifurcation ratios of the corresponding trees and discuss the relationship of these quantities to the architectural organization of the original graphs. This algorithmic framework decouples the geometric information (exact location of edges and nodes) from the metric topology (connectivity and edge weight) and it ultimately allows us to perform a quantitative statistical comparison between predictions of theoretical models and naturally occurring loopy graphs.Comment: 17 pages, 8 figures. During preparation of this manuscript the authors became aware of the work of Mileyko at al., concurrently submitted for publicatio
    corecore