1,753 research outputs found

    A Comprehensive Survey on RF Energy Harvesting: Applications and Performance Determinants

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    \ua9 2022 by the authors. Licensee MDPI, Basel, Switzerland.There has been an explosion in research focused on Internet of Things (IoT) devices in recent years, with a broad range of use cases in different domains ranging from industrial automation to business analytics. Being battery-powered, these small devices are expected to last for extended periods (i.e., in some instances up to tens of years) to ensure network longevity and data streams with the required temporal and spatial granularity. It becomes even more critical when IoT devices are installed within a harsh environment where battery replacement/charging is both costly and labour intensive. Recent developments in the energy harvesting paradigm have significantly contributed towards mitigating this critical energy issue by incorporating the renewable energy potentially available within any environment in which a sensor network is deployed. Radio Frequency (RF) energy harvesting is one of the promising approaches being investigated in the research community to address this challenge, conducted by harvesting energy from the incident radio waves from both ambient and dedicated radio sources. A limited number of studies are available covering the state of the art related to specific research topics in this space, but there is a gap in the consolidation of domain knowledge associated with the factors influencing the performance of RF power harvesting systems. Moreover, a number of topics and research challenges affecting the performance of RF harvesting systems are still unreported, which deserve special attention. To this end, this article starts by providing an overview of the different application domains of RF power harvesting outlining their performance requirements and summarizing the RF power harvesting techniques with their associated power densities. It then comprehensively surveys the available literature on the horizons that affect the performance of RF energy harvesting, taking into account the evaluation metrics, power propagation models, rectenna architectures, and MAC protocols for RF energy harvesting. Finally, it summarizes the available literature associated with RF powered networks and highlights the limitations, challenges, and future research directions by synthesizing the research efforts in the field of RF energy harvesting to progress research in this area

    Scale Anomaly and Quantum Chaos in the Billiards with Pointlike Scatterers

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    We argue that the random-matrix like energy spectra found in pseudointegrable billiards with pointlike scatterers are related to the quantum violation of scale invariance of classical analogue system. It is shown that the behavior of the running coupling constant explains the key characteristics of the level statistics of pseudointegrable billiards.Comment: 10 pages, RevTex file, uuencode

    Cuentos y poemas griegos modernos para niños y gente joven

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    El Centro de Estudios Bizantinos y Neohelénicos, perteneciente a nuestra Facultad de Filosofía y Humanidades, ha venido realizando una plausible labor de traducción directa y edición de la literatura neogriega. Destacan en esta línea editorial los libros de grandes figuras de la poesía, y diversas antologías, como las de cuentistas contemporáneos y de mujeres. Cada obra es presentada con estudios preliminares y un interesante aparato crítico.  

    Pulmonary fibrosis presenting as an early manifestation of microscopic polyangiitis

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    Microscopic polyangiitis (MPA) is a systemic small vessel vasculitis that is included in the pulmonary-renal syndromes. Although glomerulonephritis represents the major clinical feature of MPA indicative of renal involvement, diffuse alveolar haemorrhage is the classic manifestation of pulmonary involvement. However, pulmonary fibrosis is a less frequently reported pulmonary manifestation. Herein we describe a patient who was diagnosed with MPA presenting with radiographic evidence of pulmonary interstitial fibrosis as an early clinical manifestation accompanied by constitutional symptoms such as fever and weight loss. We also include a short literature review focusing on the association between pulmonary fibrosis and MPA

    Electronic Devices Based on Purified Carbon Nanotubes Grown By High Pressure Decomposition of Carbon Monoxide

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    The excellent properties of transistors, wires, and sensors made from single-walled carbon nanotubes (SWNTs) make them promising candidates for use in advanced nanoelectronic systems. Gas-phase growth procedures such as the high pressure decomposition of carbon monoxide (HiPCO) method yield large quantities of small diameter semiconducting SWNTs, which are ideal for use in nanoelectronic circuits. As-grown HiPCO material, however, commonly contains a large fraction of carbonaceous impurities that degrade properties of SWNT devices. Here we demonstrate a purification, deposition, and fabrication process that yields devices consisting of metallic and semiconducting nanotubes with electronic characteristics vastly superior to those of circuits made from raw HiPCO. Source-drain current measurements on the circuits as a function of temperature and backgate voltage are used to quantify the energy gap of semiconducting nanotubes in a field effect transistor geometry. This work demonstrates significant progress towards the goal of producing complex integrated circuits from bulk-grown SWNT material.Comment: 6 pages, 4 figures, to appear in Nature Material

    Level spacing distribution of pseudointegrable billiard

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    In this paper, we examine the level spacing distribution P(S)P(S) of the rectangular billiard with a single point-like scatterer, which is known as pseudointegrable. It is shown that the observed P(S)P(S) is a new type, which is quite different from the previous conclusion. Even in the strong coupling limit, the Poisson-like behavior rather than Wigner-like is seen for S>1S>1, although the level repulsion still remains in the small SS region. The difference from the previous works is analyzed in detail.Comment: 11 pages, REVTeX file, 3 PostScript Figure

    Psychological distress and quality of life in lung cancer: The role of health-related stigma, illness appraisals and social constraints

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    Objective: Health-related stigma is associated with negative psychological and quality of life outcomes in lung cancer patients. This study describes the impact of stigma on lung cancer patients\u27 psychological distress and quality of life and explores the role of social constraints and illness appraisal as mediators of effect. Methods: A self-administered cross-sectional survey examined psychological distress and quality of life in 151 people (59% response rate) diagnosed with lung cancer from Queensland and New South Wales. Health-related stigma, social constraints and illness appraisals were assessed as predictors of adjustment outcomes. Results: Forty-nine percent of patients reported elevated anxiety; 41% were depressed; and 51% had high global distress. Health-related stigma was significantly related to global psychological distress and quality of life with greater stigma and shame related to poorer outcomes. These effects were mediated by illness appraisals and social constraints. Conclusions: Health-related stigma appears to contribute to poorer adjustment by constraining interpersonal discussions about cancer and heightening feelings of threat. There is a need for the development and evaluation of interventions to ameliorate the negative effects of health-related stigma among lung cancer patients

    Surface patterning of carbon nanotubes can enhance their penetration through a phospholipid bilayer

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    Nanotube patterning may occur naturally upon the spontaneous self-assembly of biomolecules onto the surface of single-walled carbon nanotubes (SWNTs). It results in periodically alternating bands of surface properties, ranging from relatively hydrophilic to hydrophobic, along the axis of the nanotube. Single Chain Mean Field (SCMF) theory has been used to estimate the free energy of systems in which a surface patterned nanotube penetrates a phospholipid bilayer. In contrast to un-patterned nanotubes with uniform surface properties, certain patterned nanotubes have been identified that display a relatively low and approximately constant system free energy (10 kT) as the nanotube traverses through the bilayer. These observations support the hypothesis that the spontaneous self-assembly of bio-molecules on the surface of SWNTs may facilitate nanotube transduction through cell membranes.Comment: Published in ACS Nano http://pubs.acs.org/doi/abs/10.1021/nn102763

    Factors predictive of treatment by Australian breast surgeons of invasive female breast cancer by mastectomy rather than breast conserving surgery

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    Background: The National Breast Cancer Audit Database of the Society of Breast Surgeons of Australia and New Zealand is used by surgeons to monitor treatment quality and for research. About 60% of early invasive female breast cancers in Australia are recorded. The objectives of this study are: (1) to investigate associations of socio-demographic, health-system and clinical characteristics with treatment of invasive female breast cancer by mastectomy compared with breast conserving surgery; and (2) to consider service delivery implications. Materials and Methods: Bi-variable and multivariable analyses of associations of characteristics with surgery type for cancers diagnosed in 1998-2010. Results: Of 30,299 invasive cases analysed, 11,729 (39%) were treated by mastectomy as opposed to breast conserving surgery. This proportion did not vary by diagnostic year (p>0.200). With major city residence as the reference category, the relative rate (95% confidencelimits) of mastectomy was 1.03 (0.99, 1.07) for women from inner regional areas and 1.05 (1.01, 1.10) for those from more remote areas. Low annual surgeon case load (≤10) was predictive of mastectomy, with a relative rate of 1.08 (1.03, 1.14) when compared with higher case loads. Tumour size was also predictive, with a relative rate of 1.05 (1.01, 1.10) for large cancers (40+ mm) compared with smaller cancers (<30 mm). These associations were confirmedin multiple logistic regression analysis. Conclusions: Results confirmprevious studies showing higher mastectomy rates for residents of more remote areas, those treated by surgeons with low case loads, and those with large cancers. Reasons require further study, including possible effects of surgeon and woman’s choice and access to radiotherapy services.David Roder, Helen Zorbas, James Kollias, Chris Pyke, David Walters, Ian Campbell, Corey Taylor, Fleur Webste

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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