190 research outputs found

    Josephson Junctions and AdS/CFT Networks

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    We propose a new holographic model of Josephson junctions (and networks thereof) based on designer multi-gravity, namely multi-(super)gravity theories on products of distinct asymptotically AdS spacetimes coupled by mixed boundary conditions. We present a simple model of a Josephson junction (JJ) that exhibits the well-known current-phase sine relation of JJs. In one-dimensional chains of holographic superconductors we find that the Cooper-pair condensates are described by a discretized Schrodinger-type equation. Such non-integrable equations, which have been studied extensively in the past in condensed matter and optics applications, are known to exhibit complex behavior that includes periodic and quasiperiodic solutions, chaotic dynamics, soliton and kink solutions. In our setup these solutions translate to holographic configurations of strongly-coupled superconductors in networks with weak site-to-site interactions that exhibit interesting patterns of modulated superconductivity. In a continuum limit our equations reduce to generalizations of the Gross-Pitaevskii equation. We comment on the many possible extensions and applications of this new approach.Comment: 39 pages, 11 figures; v2 clarified the nature and computation of the Josephson current in subsec. 3.2 and specific properties of the two-site system, analogous minor modifications in subsec. 4.4 and added a new subsec. 4.5 with a new fig.

    Proteomic Analysis of Aortae from Human Lipoprotein(a) Transgenic Mice Shows an Early Metabolic Response Independent of Atherosclerosis

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    Background: Elevated low density lipoprotein (LDL) and lipoprotein(a) are independent risk factors for the development of atherosclerosis. Using a proteomic approach we aimed to determine early changes in arterial protein expression in transgenic mice containing both human LDL and lipoprotein(a) in circulation. Methods and Results: Plasma lipid analyses showed the lipoprotein(a) transgenic mice had significantly higher lipid levels than wildtype, including a much increased LDL and high density lipoprotein (HDL) cholesterol. Analysis of aortae from lipoprotein(a) mice showed lipoprotein(a) accumulation but no lipid accumulation or foam cells, leaving the arteries essentially atherosclerosis free. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 34 arterial proteins with significantly altered abundance (P,0.05) in lipoprotein(a) transgenic mice compared to wildtype including 17 that showed a $2 fold difference. Some proteins of interest showed a similarly altered abundance at the transcript level. These changes collectively indicated an initial metabolic response that included a down regulation in energy, redox and lipid metabolism proteins and changes in structural proteins at a stage when atherosclerosis had not yet developed. Conclusions: Our study shows that human LDL and lipoprotein(a) promote changes in the expression of a unique set o

    Consumer and staff perspectives of the implementation frequency and value of recovery and wellbeing oriented practices

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    Background: Despite advances in our understanding of what mental health systems and services can do to enhance recovery and wellbeing outcomes for people seeking support, there is limited evidence demonstrating that this body of work has translated successfully into mental health service practice. The Collaborative Recovery Model (CRM) is a practice framework that has been designed to support application of recovery and wellbeing oriented principles and practices within mental health service delivery. The aims of this study were to assess consumer and staff perceptions of implementation frequency during service engagement and the value of this approach for assisting recovery within a setting where the CRM approach had been adopted. Methods: The setting was a large Australian community managed mental health organisation. The study involved a cross-sectional analysis of consumer (n = 116) and staff practitioner (n = 62) perspectives. A series of paired sample t-tests assessed for differences between consumer and staff perceptions of the: (i) importance of key practice elements for assisting recovery, and the (ii) frequency that key practice elements are utilised during engagement sessions. Spearman\u27s r correlational analysis explored associations between importance, frequency and helpfulness of sessions. Results: Key practice elements of the model were applied during service interactions at a high level and perceived by the majority of consumers and staff participants as being important or very important for assisting recovery. Significant moderate correlations were found between the extent that practice elements were valued and the level at which they were applied. Higher levels of implementation of CRM practices were associated with higher ratings of perceived session helpfulness. The strongest association was between \u27encouragement to set tasks to complete between support visits\u27 and perceived helpfulness. Conclusions: Consumer and staff responses revealed that the key practice elements of the CRM were frequently implemented during service engagement interactions and were seen as valuable for assisting recovery. The level of agreement between raters suggests firstly, that the key practice elements were apparent and able to be rated as occurring, and secondly that the CRM approach is seen as responsive to consumer needs. The results have implications for translating recovery and wellbeing oriented knowledge into mental health service practice

    Kidney stones and hypertension: an independent clinical association in a population-based study

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