1,034 research outputs found

    A Gravitational Theory of the Quantum

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    The synthesis of quantum and gravitational physics is sought through a finite, realistic, locally causal theory where gravity plays a vital role not only during decoherent measurement but also during non-decoherent unitary evolution. Invariant set theory is built on geometric properties of a compact fractal-like subset IUI_U of cosmological state space on which the universe is assumed to evolve and from which the laws of physics are assumed to derive. Consistent with the primacy of IUI_U, a non-Euclidean (and hence non-classical) state-space metric gpg_p is defined, related to the pp-adic metric of number theory where pp is a large but finite Pythagorean prime. Uncertain states on IUI_U are described using complex Hilbert states, but only if their squared amplitudes are rational and corresponding complex phase angles are rational multiples of 2π2 \pi. Such Hilbert states are necessarily gpg_p-distant from states with either irrational squared amplitudes or irrational phase angles. The gappy fractal nature of IUI_U accounts for quantum complementarity and is characterised numerically by a generic number-theoretic incommensurateness between rational angles and rational cosines of angles. The Bell inequality, whose violation would be inconsistent with local realism, is shown to be gpg_p-distant from all forms of the inequality that are violated in any finite-precision experiment. The delayed-choice paradox is resolved through the computational irreducibility of IUI_U. The Schr\"odinger and Dirac equations describe evolution on IUI_U in the singular limit at p=∞p=\infty. By contrast, an extension of the Einstein field equations on IUI_U is proposed which reduces smoothly to general relativity as p→∞p \rightarrow \infty. Novel proposals for the dark universe and the elimination of classical space-time singularities are given and experimental implications outlined

    Optical measurement of torque exerted on an elongated object by a non-circular laser beam

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    We have developed a scheme to measure the optical torque, exerted by a laser beam on a phase object, by measuring the orbital angular momentum of the transmitted beam. The experiment is a macroscopic simulation of a situation in optical tweezers, as orbital angular momentum has been widely used to apply torque to microscopic objects. A hologram designed to generate LG02 modes and a CCD camera are used to detect the orbital component of the beam. Experimental results agree with theoretical numerical calculations, and the strength of the orbital component suggest its usefulness in optical tweezers for micromanipulation.Comment: 6 pages, 7 figures, v2: minor typographical correction

    Non-pharmacological self-management strategies for chemotherapy-induced peripheral neuropathy in people with advanced cancer: A systematic review and meta-analysis

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    Non-pharmacological self-management interventions for chemotherapy-induced peripheral neurotherapy (CIPN) are of clinical interest; however, no systematic review has synthesized the evidence for their use in people with advanced cancer. Five databases were searched from inception to February 2022 for randomized controlled trials assessing the effect of non-pharmacological self-management interventions in people with advanced cancer on the incidence and severity of CIPN symptoms and related outcomes compared to any control condition. Data were pooled with metaanalysis. Quality of evidence was appraised using the Revised Cochrane Risk of Bias Tool for Randomized Trials (RoB2), with data synthesized narratively. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was applied to assess the certainty of the evidence. Thirteen studies were included, which had a high (69 %) or unclear (31 %) risk of bias. Greatest confidence was found for physical exercise decreasing CIPN severity (SMD: −0.89, 95 % CI: −1.37 to −0.41; p = 0.0003; I2 = 0 %; n = 2 studies, n = 76 participants; GRADE level: moderate) and increasing physical function (SMD: 0.51, 95 % CI: 0.02 to 1.00; p = 0.04; I2 = 42 %; n = 3 studies, n = 120; GRADE level: moderate). One study per intervention provided preliminary evidence for the positive effects of glutamine supplementation, an Omega-3 PUFA-enriched drink, and education for symptom self-management via a mobile phone game on CIPN symptoms and related outcomes (GRADE: very low). No serious adverse events were reported. The strongest evidence with the most certainty was found for physical exercise as a safe and viable adjuvant to chemotherapy treatment for the prevention and management of CIPN and related physical function in people with advanced cancer. However, the confidence in the evidence to inform conclusions was mostly very low to moderate. Future well-powered and appropriately designed interventions for clinical trials using validated outcome measures and clearly defined populations and strategies are warranted

    Trace formulae for non-equilibrium Casimir interactions, heat radiation and heat transfer for arbitrary objects

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    We present a detailed derivation of heat radiation, heat transfer and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal non-equilibrium. The results can be expressed as basis-independent trace formulae in terms of the scattering operators of the individual objects. We prove that heat radiation of a single object is positive, and that heat transfer (for two arbitrary passive objects) is from the hotter to a colder body. The heat transferred is also symmetric, exactly reversed if the two temperatures are exchanged. Introducing partial wave-expansions, we transform the results for radiation, transfer and forces into traces of matrices that can be evaluated in any basis, analogous to the equilibrium Casimir force. The method is illustrated by (re)deriving the heat radiation of a plate, a sphere and a cylinder. We analyze the radiation of a sphere for different materials, emphasizing that a simplification often employed for metallic nano-spheres is typically invalid. We derive asymptotic formulae for heat transfer and non-equilibrium interactions for the cases of a sphere in front a plate and for two spheres, extending previous results. As an example, we show that a hot nano-sphere can levitate above a plate with the repulsive non-equilibrium force overcoming gravity -- an effect that is not due to radiation pressure.Comment: 29 pages, 6 figures (v2: Sentence added in Sec. 1

    Non-equilibrium Casimir forces: Spheres and sphere-plate

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    We discuss non-equilibrium extensions of the Casimir force (due to electromagnetic fluctuations), where the objects as well as the environment are held at different temperatures. While the formalism we develop is quite general, we focus on a sphere in front of a plate, as well as two spheres, when the radius is small compared to separation and thermal wavelengths. In this limit the forces can be expressed analytically in terms of the lowest order multipoles, and corroborated with results obtained by diluting parallel plates of vanishing thickness. Non-equilibrium forces are generally stronger than their equilibrium counterpart, and may oscillate with separation (at a scale set by material resonances). For both geometries we obtain stable points of zero net force, while two spheres may have equal forces in magnitude and direction resulting in a self-propelling state.Comment: 6 pages, 6 figure

    A metadata-aware application for remote scoring and exchange of tissue microarray images.

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    BACKGROUND: The use of tissue microarrays (TMA) and advances in digital scanning microscopy has enabled the collection of thousands of tissue images. There is a need for software tools to annotate, query and share this data amongst researchers in different physical locations. RESULTS: We have developed an open source web-based application for remote scoring of TMA images, which exploits the value of Microsoft Silverlight Deep Zoom to provide a intuitive interface for zooming and panning around digital images. We use and extend existing XML-based standards to ensure that the data collected can be archived and that our system is interoperable with other standards-compliant systems. CONCLUSION: The application has been used for multi-centre scoring of TMA slides composed of tissues from several Phase III breast cancer trials and ten different studies participating in the International Breast Cancer Association Consortium (BCAC). The system has enabled researchers to simultaneously score large collections of TMA and export the standardised data to integrate with pathological and clinical outcome data, thereby facilitating biomarker discovery.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Neutron small-angle scattering of E. coli

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    Benefits of supportive strategies for carers of people with high-grade glioma: a systematic review: Strategies for addressing the needs of high-grade glioma carers

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    Purpose: To systematically review and examine current evidence for the carer-reported benefits of supportive care strategies for carers of adults with high-grade glioma (HGG). Methods: Four databases (CINAHL, EMBASE, PubMed, PsycINFO) were searched for articles published between January 2005 and April 2022 that assessed strategies for addressing the supportive care needs of carers of adults with HGG (WHO grade 3–4). Study selection and critical appraisal were conducted independently by three authors (DJ/MC, 2021; DJ/RJ 2022). Data extraction was conducted by one author (DJ) and checked by a second author (RJ). Results were synthesised narratively. Results: Twenty-one studies involving 1377 caregivers were included, targeting the carer directly (n = 10), the patient-carer dyad (n = 3), or focused on people with HGG + / − their carers (n = 8). A paucity of high-quality evidence exists for effective and comprehensive support directly addressing outcomes for carers of adults with HGG. Strategies that demonstrated some benefits included those that built carer knowledge or provided emotional support, delivered by health professionals or through peer support. Supportive and early palliative care programmes have potential to reduce unmet carer needs while providing ongoing carer support. Conclusion: Strategies incorporating an educational component, emotional support, and a regular needs assessment with corresponding tailored support are most valued by carers. Future practice development research should adopt a value-based approach and exceed evaluation of efficacy outcomes to incorporate evaluation of the experience of patients, carers, and staff, as well as costs

    Strengthening the research to policy and practice interface: exploring strategies used by research organisations working on sexual and reproductive health and HIV/AIDS

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    This commentary introduces the HARPS supplement on getting research into policy and practice in sexual and reproductive health (SRH). The papers in this supplement have been produced by the Sexual Health and HIV Evidence into Practice (SHHEP) collaboration of international research, practitioner and advocacy organizations based in research programmes funded by the UK Department for International Development
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