2,295 research outputs found

    Individually-rational collective choice

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    There is a collection of exogenously given socially-feasible sets, and, for each one of them, each individual in a group chooses from an individually-feasible set. The fact that the product of the individually-feasible sets is larger than the socially-feasible set notwithstanding, there arises no conflict between individual choices. Assuming that individual preferences are random, I characterize rationalizable collective choices

    Phase diagram and magnetic properties of La1x_{1-x}Cax_xMnO3_3 compound for 0x0.230\leq x \leq 0.23

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    In this article a detailed study of La1x_{1-x}Cax_xMnO3_3 (0x0.230\leq x \leq 0.23) phase diagram using powder x-ray diffraction and magnetization measurements is presented. Unfortunately, in the related literature no properly characterized samples have been used, with consequence the smearing of the real physics in this complicated system. As the present results reveal, there are two families of samples. The first family concerns samples prepared in atmosphere (P(O2)=0.2P({\rm O}_2)=0.2 Atm) which are all ferromagnetic with Curie temperature rising with xx. The second family concerns samples, where a post annealing in nearly zero oxygen partial pressure is applied. These samples show a canted antiferromagnetic structure for 0x0.10\leq x \leq 0.1 below TNT_N, while for 0.125x<0.230.125\leq x <0.23 an unconventional ferromagnetic insulated phase is present below TcT_c. The most important difference between nonstoichiometric and stoichiometric samples concerning the magnetic behavior, is the anisotropy in the exchange interactions, in the stoichiometric samples putting forward the idea that a new orbital ordered phase is responsible for the ferromagnetic insulating regime in the La1x_{1-x}Cax_xMnO3_3 compound

    Mimicry and mitonuclear discordance in nudibranchs : new insights from exon capture phylogenomics

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    Open access via the Wiley Jisc Agreement Funding Information Gorgon Barrow Island Net Conservation Benefits Fund The University of Western Australia Malacological Society of Australasia ACKNOWLEDGEMENTS We are grateful to our collaborators who have contributed specimens to this work, including David Mullins, Gary Cobb, Greg Rouse, Karen Cheney, Kate Dawson, Lisa Kirkendale, Terry Farr, and Terry Gosliner. We also thank Elizabeth Kools for coordinating K.K.S.L's tissue sampling at the California Academy of Sciences and for sending specimens for this work. We sincerely thank Alison Devault and Jakob Enk from Arbor Biosciences for logistical support and advice, and Greg Rouse, Joel Huey, and Josefin Stiller for feedback on data analysis. Funding for this project comes from the Gorgon Project's Barrow Island Net Conservation Benefits Fund, The University of Western Australia, and the Malacological Society of Australasia. K.K.S.L. was supported by a University Postgraduate Award for International Students (UPAIS) and an RTP International Fees Offset scholarship (RTPFI) administered by the University of Western Australia, as well as a postgraduate doctoral scholarship from the Natural Sciences and Engineering Research Council of Canada (NSERC). Here we provide permit details for newly collected specimens that do not derive from Layton et al. (2018). Specimens from Western Australia were collected under permits from the Department of Parks and Wildlife, including a regulation 17 licence to collect fauna for scientific purposes (SF010218, SF010710) and a regulation 4 exemption to collect marine invertebrates within Ningaloo Marine Park (CE005306). Specimens from Queensland were collected under permits from the Department of Agriculture, Fisheries and Forestry (Permit #: 183990). Specimens from Victoria were collected under permits from the Department of Environment, Land, Water and Planning (Permit #: 10007853). The specimen from California was collected under a permit from California Department of Fish and Wildlife (Permit #: 4564).Peer reviewedPublisher PD

    High-pressure synthesis of rock salt LiMeO2-ZnO (Me = Fe3+, Ti3+) solid solutions

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    Metastable LiMeO2-ZnO (Me = Fe3+, Ti3+) solid solutions with rock salt crystal structure have been synthesized by solid state reaction of ZnO with LiMeO2 complex oxides at 7.7 GPa and 1350-1450 K. Structure, phase composition, thermal stability and thermal expansion of the recovered samples have been studied by X-ray diffraction with synchrotron radiation. At ambient pressure rock salt LiMeO2-ZnO solid solutions are kinetically stable up to 670-800 K depending on the composition.Comment: 11 pages, 3 figures, 1 tabl

    Improved prediction of the optical properties in pi-conjugated polymers: the case of benzochalcogenodiazole-based copolymers with different heteroatom substitution

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    Donor−acceptor (D−A) approach to conjugated polymer design has become a widely used method for preparing conjugated polymers with narrow band gaps.1 One outstanding D−A polymer is poly(cyclopentadithiophene)benzothiadiazole, PCPDTBT (P1 in Figure 1), for which power conversion efficiencies in solar cells of 4.5-5.5% are reported.2 In this work, we use resonance Raman (RR) and density functional theory (DFT) calculations to investigate the tuning of the electronic and structural properties of cyclopentadithiophene-benzochalcogenodiazole D−A polymers, wherein a single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium to tellurium (Fig. 1).3 Sophisticated DFT calculations have been carried out using long-range corrected functionals, considering both tuned and default range-separation parameters, aiming at predicting their optical and charge transport properties. In addition, the nature of the electronic excitation is described by analyzing the enhancement pattern in the RR spectra using Raman excitation wavelengths coincident with the various transitions in the copolymers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Multiferroic behavior in the new double-perovskite Lu2_2MnCoO6_6

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    We present a new member of the multiferroic oxides, Lu2_2MnCoO6_6, which we have investigated using X-ray diffraction, neutron diffraction, specific heat, magnetization, electric polarization, and dielectric constant measurements. This material possesses an electric polarization strongly coupled to a net magnetization below 35 K, despite the antiferromagnetic ordering of the S=3/2S = 3/2 Mn4+^{4+} and Co2+^{2+} spins in an \uparrow \uparrow \downarrow \downarrow configuration along the c-direction. We discuss the magnetic order in terms of a condensation of domain boundaries between \uparrow \uparrow and \downarrow \downarrow ferromagnetic domains, with each domain boundary producing a net electric polarization due to spatial inversion symmetry breaking. In an applied magnetic field the domain boundaries slide, controlling the size of the net magnetization, electric polarization, and magnetoelectric coupling

    Structure and magnetic order in Fe2+xV1-xAl

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    We present a detailed structural investigation via neutron diffraction of differently heat treated samples Fe2VAl and Fe2+xV1-xAl. Moreover, the magnetic behaviour of these materials is studied by means of mSR and Mossbauer-experiments. Our structural investigation indicates that quenched Fe2VAl, exhibiting the previously reported "Kondo insulating like" behaviour, is off-stoichiometric (6%) in its Al content. Slowly cooled Fe2VAl is structurally better ordered and stoichiometric, and the microscopic magnetic probes establish long range ferromagnetic order below TC = 13K, consistent with results from bulk experiments. The magnetic state can be modelled as being generated by diluted magnetic ions in a non-magnetic matrix. Quantitatively, the required number of magnetic ions is too large as to be explained by a model of Fe/V site exchange. We discuss the implications of our findings for the ground state properties of Fe2VAl, in particular with respect to the role of crystallographic disorder.Comment: accepted for publication in J. Phys.: Condens. Matte

    Formation of collective spins in frustrated clusters

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    Using magnetization, specific heat and neutron scattering measurements, as well as exact calculations on realistic models, the magnetic properties of the \lacuvo compound are characterized on a wide temperature range. At high temperature, this oxide is well described by strongly correlated atomic SS=1/2 spins while decreasing the temperature it switches to a set of weakly interacting and randomly distributed entangled pseudo spins S~=1/2\tilde S=1/2 and S~=0\tilde S=0. These pseudo-spins are built over frustrated clusters, similar to the kagom\'e building block, at the vertices of a triangular superlattice, the geometrical frustration intervening then at different scales.Comment: 10 page
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