13,258 research outputs found

    Answer Sets for Logic Programs with Arbitrary Abstract Constraint Atoms

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    In this paper, we present two alternative approaches to defining answer sets for logic programs with arbitrary types of abstract constraint atoms (c-atoms). These approaches generalize the fixpoint-based and the level mapping based answer set semantics of normal logic programs to the case of logic programs with arbitrary types of c-atoms. The results are four different answer set definitions which are equivalent when applied to normal logic programs. The standard fixpoint-based semantics of logic programs is generalized in two directions, called answer set by reduct and answer set by complement. These definitions, which differ from each other in the treatment of negation-as-failure (naf) atoms, make use of an immediate consequence operator to perform answer set checking, whose definition relies on the notion of conditional satisfaction of c-atoms w.r.t. a pair of interpretations. The other two definitions, called strongly and weakly well-supported models, are generalizations of the notion of well-supported models of normal logic programs to the case of programs with c-atoms. As for the case of fixpoint-based semantics, the difference between these two definitions is rooted in the treatment of naf atoms. We prove that answer sets by reduct (resp. by complement) are equivalent to weakly (resp. strongly) well-supported models of a program, thus generalizing the theorem on the correspondence between stable models and well-supported models of a normal logic program to the class of programs with c-atoms. We show that the newly defined semantics coincide with previously introduced semantics for logic programs with monotone c-atoms, and they extend the original answer set semantics of normal logic programs. We also study some properties of answer sets of programs with c-atoms, and relate our definitions to several semantics for logic programs with aggregates presented in the literature

    Strategies for replacing saturated fat in meat products: A review

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    This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term.This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term

    Infrared Hall conductivity of Na0.7_{0.7}CoO2_2

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    We report infrared Hall conductivity σxy(ω)\sigma_{xy}(\omega) of Na0.7_{0.7}CoO2_2 thin films determined from Faraday rotation angle θF\theta_{F} measurements. σxy(ω)\sigma_{xy}(\omega) exhibits two types of hole conduction, Drude and incoherent carriers. The coherent Drude carrier shows a large renormalized mass and Fermi liquid-like behavior of Hall scattering rate, γHaT2\gamma_{H} \sim aT^{2}. The spectral weight is suppressed and disappears at T = 120K. The incoherent carrier response is centered at mid-IR frequency and shifts to lower energy with increasing T. Infrared Hall constant is positive and almost independent of temperature in sharp contrast with the dc-Hall constant.Comment: 5 Pages, 5 Figures. Author list corrected in metadata only, paper is unchange

    Microalgae as alternative proteins for the sustainable food industry: A review

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    This paper reviews the nutritional properties and consumer perceptions of microalgae foods through various recent studies on alternative protein sources. Food choices, including meat consumption, are a common concern for humanity. Thus, we focused on whether microalgae foods have a sufficient value as a protein source and what nutritional benefits they have. Based on existing papers, we conducted a systematic review using Web of Science, Google Scholar, and Scopus to comprehensively investigate and summarize the nutritional characteristics of microalgae, sustainable diets, and awareness of microalgae as an alternative protein source. Research has shown that microalgae have been consumed by humans as a protein source since ancient times, and contain enough protein to be used as an alternative protein source. They also have many other nutritional benefits, such as vitamins. We have found that consumers are increasingly interested in alternative protein sources, and the more they learn about microalgae, the more accepting they become. These results may suggest a need for further research to improve microalgae as an alternative protein source in the long run and develop them into a variety of foods

    Chiral Anomaly and Classical Negative Magnetoresistance of Weyl Metals

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    We consider the classical magnetoresistance of a Weyl metal in which the electron Fermi surface possess nonzero fluxes of the Berry curvature. Such a system may exhibit large negative magnetoresistance with unusual anisotropy as a function of the angle between the electric and magnetic fields. In this case the system can support a new type of plasma waves. These phenomena are consequences of chiral anomaly in electron transport theory.Comment: 4 pages, 2 figure

    Clustering of vacancy defects in high-purity semi-insulating SiC

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    Positron lifetime spectroscopy was used to study native vacancy defects in semi-insulating silicon carbide. The material is shown to contain (i) vacancy clusters consisting of 4--5 missing atoms and (ii) Si vacancy related negatively charged defects. The total open volume bound to the clusters anticorrelates with the electrical resistivity both in as-grown and annealed material. Our results suggest that Si vacancy related complexes compensate electrically the as-grown material, but migrate to increase the size of the clusters during annealing, leading to loss of resistivity.Comment: 8 pages, 5 figure

    Asymptotic deconfinement in high-density QCD

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    We discuss QCD with two light flavors at large baryon chemical potential mu. Color superconductivity leads to partial breaking of the color SU(3) group. We show that the infrared physics is governed by the gluodynamics of the remaining SU(2) group with an exponentially soft confinement scale Lambda_QCD' Delta*exp[-a*mu/(g*Delta)], where Delta<<mu is the superconducting gap, g is the strong coupling, and a=0.81... We estimate that at moderate baryon densities Lambda_QCD' is O(10 MeV) or smaller. The confinement radius increases exponentially with density, leading to "asymptotic deconfinement." The velocity of the SU(2) gluons is small due to the large dielectric constant of the medium.Comment: 4 pages; restructured, published versio

    (Non)-Renormalization of the Chiral Vortical Effect Coefficient

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    We show using diagramtic arguments that in some (but not all) cases, the temperature dependent part of the chiral vortical effect coefficient is independent of the coupling constant. An interpretation of this result in terms of quantization in the effective 3 dimensional Chern-Simons theory is also given. In the language of 3D dimensionally reduced theory, the value of the chiral vortical coefficient is related to the formula n=1n=1/12\sum_{n=1}^\infty n=-1/12. We also show that in the presence of dynamical gauge fields, the CVE coefficient is not protected from renormalization, even in the large NN limit.Comment: 11 pages, 3 figures. Version 2 corrects an error and calculates leading radiative correctio

    Spin Currents Induced by Nonuniform Rashba-Type Spin-Orbit Field

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    We study the spin relaxation torque in nonmagnetic or ferromagnetic metals with nonuniform spin-orbit coupling within the Keldysh Green's function formalism. In non-magnet, the relaxation torque is shown to arise when the spin-orbit coupling is not uniform. In the absence of an external field, the spin current induced by the relaxation torque is proportional to the vector chirality of Rashba-type spin-orbit field (RSOF). In the presence of an external field, on the other hand, spin relaxation torque arises from the coupling of the external field and vector chirality of RSOF. Our result indicates that spin-sink or source effects are controlled by designing RSOF in junctions.Comment: 3 figure

    Physicochemical Properties and Catalytic Behavior of the Molecular Sieve SSZ-70

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    SSZ-70 is synthesized using 1,3-bis(isobutyl)imidazolium, 1,3-bis(cyclohexyl)imidazolium, and 1,3-bis(cycloheptyl)imidazolium structure directing agents (SDAs), and the solids obtained are characterized by powder X-ray diffraction (XRD), ^(29)Si magic angle spinning nuclear magnetic resonance (MAS NMR), electron microscopy, nitrogen and hydrocarbon adsorption, and thermogravimetric analyses. The physicochemical properties of SSZ-70 show that it is a new molecular sieve that has similarities to MWW-type materials. The catalytic behavior of SSZ-70 is evaluated through the use of the constraint index (CI) test. Distinct differences in the reactivity between Al-SSZ-70 and SSZ-25 (MWW) are observed and are the consequences of the structural differences between these two molecular sieves
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