12,624 research outputs found

    Management Measures of Shrimp Trawling Fishery in Arafura Sea, Indonesia: a Challenge

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    Since there were many evidences on trawling impact to the environment and society, government has banned trawl operations in Indonesian waters except for those in the Arafura Sea. It is not solely acquitted trawl operation in the area without restrain, but it has been put together with the measures taken to exploit the shrimp resources in optimal manner. Those are input controls, output controls and technical measures. This paper examines two major challenges in applying these management measures: declining of shrimp stock and lack of legal enforcement. Come what may the fishing regulations impose in the shrimp trawling, without effective enforcement, the purpose of fisheries management unlikely will be achieved

    Metal-Acid Synergy: Hydrodeoxygenation of Anisole over Pt/Al-SBA-15

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    Invited for this month′s cover is the group of Karen Wilson and Adam Lee at RMIT University. The image shows platinum nanoparticles and Brønsted acid sites working cooperatively to catalyse the efficient hydrodeoxygenation of phenolic lignin residues to produce sustainable biofuels. The Full Paper itself is available at 10.1002/cssc.202000764

    A mobile visual diary for personal pain management

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    Back-pain is one of the most prolific health problems within the population and costs industry lost revenue due to the amount of days people have to take off in order to recover. In this paper, we have targeted this problem and suggested a mobile app for visually diarizing the pain experience of patients. The Android platform is utilized and its technology stack forms the basis for this 3D centric application. Positive evaluations obtained provide evidence of the promising nature of the approach and indicate several future directions of research within mobile pain management

    Insight into the atomic scale structure of CaF₂-CaO-SiO₂ glasses using a combination of neutron diffraction, ²⁹Si solid state NMR, high energy X-ray diffraction, FTIR, and XPS

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    Bioactive glasses are important for biomedical and dental applications. The controlled release of key ions, which elicit favourable biological responses, is known to be the first key step in the bioactivity of these materials. Properties such as bioactivity and solubility can be tailored for specific applications. The addition of fluoride ions is particularly interesting for dental applications as it promotes the formation of fluoro-apatite. To date there have been mixed reports in the literature on how fluorine is structurally incorporated into bioactive glasses. To optimize the design and subsequent bioactivity of these glasses, it is important to understand the connections between the glass composition, structure and relevant macroscopic properties such as apatite formation and glass degradation in aqueous media. Using neutron diffraction, high energy X-ray diffraction, ²⁹Si NMR, FTIR and XPS we have investigated the atomic scale structure of mixed calcium oxide / calcium fluoride silicate based bioactive glasses. No evidence of direct Si-F bonding was observed, instead fluorine was found to bond directly to calcium resulting in mixed oxygen/fluoride polyhedra. It was therefore concluded that the addition of fluorine does not depolymerise the silicate network and that the widely used network connectivity models are valid in these oxyfluoride systems

    Surface modification of natural fibers using bacteria: Depositing bacterial cellulose onto natural fibers to create hierarchical fiber reinforced nanocomposites

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    Triggered biodegradable composites made entirely from renewable resources are urgently sought after to improve material recyclability or be able to divert materials from waste streams. Many biobased polymers and natural fibers usually display poor interfacial adhesion when combined in a composite material. Here we propose a way to modify the surfaces of natural fibers by utilizing bacteria (Acetobacter xylinum) to deposit nanosized bacterial cellulose around natural fibers, which enhances their adhesion to renewable polymers. This paper describes the process of modifying large quantities of natural fibers with bacterial cellulose through their use as substrates for bacteria during fermentation. The modified fibers were characterized by scanning electron microscopy, single fiber tensile tests, X-ray photoelectron spectroscopy, and inverse gas chromatography to determine their surface and mechanical properties. The practical adhesion between the modified fibers and the renewable polymers cellulose acetate butyrate and poly(L-lactic acid) was quantified using the single fiber pullout test

    Quantum oscillations from Fermi arcs

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    When a metal is subjected to strong magnetic field B nearly all measurable quantities exhibit oscillations periodic in 1/B. Such quantum oscillations represent a canonical probe of the defining aspect of a metal, its Fermi surface (FS). In this study we establish a new mechanism for quantum oscillations which requires only finite segments of a FS to exist. Oscillations periodic in 1/B occur if the FS segments are terminated by a pairing gap. Our results reconcile the recent breakthrough experiments showing quantum oscillations in a cuprate superconductor YBCO, with a well-established result of many angle resolved photoemission (ARPES) studies which consistently indicate "Fermi arcs" -- truncated segments of a Fermi surface -- in the normal state of the cuprates.Comment: 8 pages, 5 figure

    Random Matrix Theory and Chiral Symmetry in QCD

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    Random matrix theory is a powerful way to describe universal correlations of eigenvalues of complex systems. It also may serve as a schematic model for disorder in quantum systems. In this review, we discuss both types of applications of chiral random matrix theory to the QCD partition function. We show that constraints imposed by chiral symmetry and its spontaneous breaking determine the structure of low-energy effective partition functions for the Dirac spectrum. We thus derive exact results for the low-lying eigenvalues of the QCD Dirac operator. We argue that the statistical properties of these eigenvalues are universal and can be described by a random matrix theory with the global symmetries of the QCD partition function. The total number of such eigenvalues increases with the square root of the Euclidean four-volume. The spectral density for larger eigenvalues (but still well below a typical hadronic mass scale) also follows from the same low-energy effective partition function. The validity of the random matrix approach has been confirmed by many lattice QCD simulations in a wide parameter range. Stimulated by the success of the chiral random matrix theory in the description of universal properties of the Dirac eigenvalues, the random matrix model is extended to nonzero temperature and chemical potential. In this way we obtain qualitative results for the QCD phase diagram and the spectrum of the QCD Dirac operator. We discuss the nature of the quenched approximation and analyze quenched Dirac spectra at nonzero baryon density in terms of an effective partition function. Relations with other fields are also discussed.Comment: invited review article for Ann. Rev. Nucl. Part. Sci., 61 pages, 11 figures, uses ar.sty (included); references added and typos correcte

    Association of Over-The-Counter Pharmaceutical Sales with Influenza-Like-Illnesses to Patient Volume in an Urgent Care Setting

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    We studied the association between OTC pharmaceutical sales and volume of patients with influenza-like-illnesses (ILI) at an urgent care center over one year. OTC pharmaceutical sales explain 36% of the variance in the patient volume, and each standard deviation increase is associated with 4.7 more patient visits to the urgent care center (p<0.0001). Cross-correlation function analysis demonstrated that OTC pharmaceutical sales are significantly associated with patient volume during non-flu season (p<0.0001), but only the sales of cough and cold (p<0.0001) and thermometer (p<0.0001) categories were significant during flu season with a lag of two and one days, respectively. Our study is the first study to demonstrate and measure the relationship between OTC pharmaceutical sales and urgent care center patient volume, and presents strong evidence that OTC sales predict urgent care center patient volume year round. © 2013 Liu et al
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