1,677 research outputs found

    The chiral phase transition in charge ordered 1T-TiSe2

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    It was recently discovered that the low temperature, charge ordered phase of 1T-TiSe2 has a chiral character. This unexpected chirality in a system described by a scalar order parameter could be explained in a model where the emergence of relative phase shifts between three charge density wave components breaks the inversion symmetry of the lattice. Here, we present experimental evidence for the sequence of phase transitions predicted by that theory, going from disorder to non-chiral and finally to chiral charge order. Employing X-ray diffraction, specific heat, and electrical transport measurements, we find that a novel phase transition occurs ~7 K below the main charge ordering transition in TiSe2, in agreement with the predicted hierarchy of charge ordered phases.Comment: 5 pages, 3 figures; includes additional experimental and theoretical results; fixed typo

    High spin polarization in the ferromagnetic filled skutterudites KFe4Sb12 and NaFe4Sb12

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    The spin polarization of ferromagnetic alkali-metal iron antimonides KFe4Sb12 and NaFe4Sb12 is studied by point-contact Andreev reflection using superconducting Nb and Pb tips. From these measurements an intrinsic transport spin polarization Pt of 67% and 60% for the K and Na compound, respectively, is inferred which establishes these materials as a new class of highly spin polarized ferromagnets. The results are in accord with band structure calculations within the local spin density approximation (LSDA) that predict nearly 100% spin polarization in the density of states. We discuss the impact of calculated Fermi velocities and spin fluctuations on Pt.Comment: Pdf file with fi

    Superconductivity induced by ruthenium substitution in an iron arsenide: investigation of SrFe2-xRuxAs2 (0 <= x <= 2)

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    The magnetism in SrFe2As2 can be suppressed by electron doping through a small substitution of Fe by Co or Ni, giving way to superconductivity. We demonstrate that a massive substitution of Fe by isovalent ruthenium similarly suppresses the magnetic ordering in SrFe2-xRuxAs2 and leads to bulk superconductivity for 0.6 <= x <= 0.8. Magnetization, electrical resistivity, and specific heat data show Tc up to approx 20K. Detailed structural investigations reveal a strong decrease of the lattice parameter ratio c/a with increasing x. DFT band structure calculations are in line with the observation that the magnetic order in SrFe2-xRuxAs2 is only destabilized for large x.Comment: 6 pages, 5 figures, extended and revised versio

    A pragmatic approach to the problem of the self-adjoint extension of Hamilton operators with the Aharonov-Bohm potential

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    We consider the problem of self-adjoint extension of Hamilton operators for charged quantum particles in the pure Aharonov-Bohm potential (infinitely thin solenoid). We present a pragmatic approach to the problem based on the orthogonalization of the radial solutions for different quantum numbers. Then we discuss a model of a scalar particle with a magnetic moment which allows to explain why the self-adjoint extension contains arbitrary parameters and give a physical interpretation.Comment: 8 pages, LaTeX, to appear in J. Phys.

    Global Food System Transformation for Resilience

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    Our world is incredibly diverse and beautiful, everything we do has an impact on the environment, and our actions are intertwined. Recognizing how our actions affect the Earth on a global scale means, we need to change the way we do things. We must ensure that the value society derives from our actions comes at a low cost to the environment. A sustainable strategy to establish a resilient food system is to ensure that human demand for the Earth’s resources for food is kept within the supply of these resources. While more than 800 million people worldwide suffer from chronic malnutrition, our food systems emit roughly a third of all greenhouse emissions. Also, over 80% of our biodiversity gets lost. Hence, scaling up food system is simply not an option to feed nine to ten billion people by 2050 as we will need to produce more food in the next four decades than all of history’s farmers have harvested in the last eight thousand years. Therefore, rather than upscaling, the global food systems require transformation. Four critical aspects of this transformation include: “Boosting the small; Transforming the Big; Losing Less; and Eating Smarter.” Examining these four areas more deeply, it becomes evident that, while new technology will be critical to the transformation, government involvement, as well as better financial and behavioral change from residents and consumers, will be required. This chapter focuses on these four pillars that make up the global food system transformation for resilience

    Utilising digital health technology to support patient-healthcare provider communication in fragility fracture recovery: systematic review and meta-analysis

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    The objective of this review is to evaluate the effectiveness of digital health supported targeted patient communication versus usual provision of health information, on the recovery of fragility fractures. The review considered studies including older people, aged 50 and above, with a fragility fracture. The primary outcome was prevention of secondary fractures by diagnosis and treatment of osteoporosis, and its adherence. This review considered both experimental and quasi-experimental study designs. A comprehensive search strategy was built to identify key terms including Medical subject headings (MeSH) and applied to the multiple electronic databases. An intention to treat analysis was applied to those studies included in the meta-analysis and odds ratio was calculated with random effects. Altogether, 15 studies were considered in the final stage for this systematic review. Out of these, 10 studies were Randomised controlled trials (RCT) and five were quasi experimental studies, published between the years 2003 and 2016 with a total of 5037 participants. Five Randomised control trails were included in the meta-analysis suggesting that digital health supported interventions were overall, twice as effective when compared with the usual standard care (OR 2.13, 95% CI 1.30-3.48), despite the population sample not being homogeneous. Findings from the remaining studies were narratively interpreted

    Cocreation of a digital patient health hub to enhance education and person-centred integrated care post hip fracture: a mixed-methods study protocol

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    INTRODUCTION: Older people with hip fractures often require long-term care and a crucial aspect is the provision of quality health information to patients and their carers to support continuity of care. If patients are well informed about their health condition and caring needs, particularly posthospital discharge into the community setting, this may support recovery and improve quality of life. As internet and mobile access reach every household, it is possible to deliver a new model of service using a digital education platform as a personal health hub where both patients and their providers of care can establish a more efficient information integration and exchange process. This protocol details proposed research, which aims to develop a 'model of care' by using a digital health solution that will allow delivery of high quality and patient-centred information, integrated into the existing process delivered within the community setting. METHODS AND ANALYSIS: This phase of the study uses a pragmatic mixed-methods design and a participatory approach through engagement of patients, their carers and healthcare providers from multiple disciplines to inform the development of a digital health platform. Quantitative methods will explore health literacy and e-health literacy among older people with hip fractures admitted to the two public tertiary care hospitals in Adelaide, South Australia. Qualitative methods will provide an understanding of aspects of content and context required for the digital health platform to be developed in order to deliver quality health information. The study will use appropriate theoretical frameworks and constructs to guide the design, analysis and overall conduct of the research study. The scope of the study intends to ultimately empower patients and their carers to improve self-management and to better use coordinated services at the community level. This could prevent further falls including associated injuries or new fractures; reduce new hospital admissions and improve confidence and engagement by limiting the psychologically restrictive 'fear of falls'. ETHICS AND DISSEMINATION: The study has been approved by the Human Research Ethics Committee of the Central Adelaide Local Health Network, South Australia (SA) Health, Government of South Australia and the University of Adelaide Human Research Ethics Committee. Findings from the study will be published in suitable peer-reviewed journals and disseminated through workshops or conferences.Lalit Yadav, Tiffany K Gill, Anita Taylor, Unyime Jasper, Jen De Young, Renuka Visvanathan, Mellick J Chehad

    Did an urban perinatal health programme in Rotterdam, the Netherlands, reduce adverse perinatal outcomes? Register-based retrospective cohort study

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    OBJECTIVES: To study the effect of an urban perinatal health programme in Rotterdam, the Netherlands, on perinatal outcomes. DESIGN: A retrospective cohort study with difference-in-differences analysis using individual-level perinatal outcome data from the Dutch Perinatal Registry 2003-2014 linked to Central Bureau of Statistics data of migration background and individual disposable household income. INTERVENTION: The programme consisted of perinatal health promotion, risk selection and risk-guided pregnancy care, and a new primary care child birth centre. The programme was implemented during 2009-2012. PRIMARY OUTCOME MEASURES: We compared trends in perinatal mortality, preterm delivery and small-for-gestational-age births between targeted urban neighbourhoods in Rotterdam (n=61 415) and all other urban neighbourhoods in the Netherlands (n=881 202). The effect of the programme was modelled as a change in trend of each perinatal outcome in the treatment group post intervention compared with the control population from January 2010 onwards. All analyses were adjusted for maternal age, parity, ethnicity and individual-level low socioeconomic status (SES). We also conducted a stratified analysis by SES. RESULTS: During 2003-2014, downward trends in perinatal mortality (adjusted OR (aOR) 0.9439 per year, 95% CI 0.9362 to 0.9517), preterm birth (aOR 0.9970 per year, 95% CI 0.9944 to 0.9997) and small-for-gestational-age births (aOR 0.9809 per year, 95% CI 0.9787 to 0.9831) in the entire study population were observed. No demonstrable changes in these trends were found in the intervention group after the prog
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