509 research outputs found

    Gender discourse, awareness, and alternative responses for men in everyday living

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    In this paper, the authors use examples from their experiences to explore the nuances and complexities of contemporary gender practices. They draw on discourse and positioning theories to identify the ways in which culturally dominant, and difficult to notice, gender constructions help shape everyday experiences. In addition, the authors share their view that there are benefits in developing skills in noticing contemporary practices made available by dominant gender constructions. Such noticing expands possibilities for ways of responding and relating that might produce outcomes for men and women that fit with their hopes for living

    Fermi-surface topology and the effects of intrinsic disorder in a class of charge-transfer salts containing magnetic ions: β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ (M = Ga, Cr, Fr; Υ = C₅H₅N)

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    We report high-field magnetotransport measurements on β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ, where M =Ga, Cr and Fe and Υ = C₅H₅N. We observe similar Shubnikov–de Haas oscillations in all compounds, attributable to four quasi-two-dimensional Fermi-surface pockets, the largest of which corresponds to a cross-sectional area ≈ 8.5% of the Brillouin zone. The cross-sectional areas of the pockets are in agreement with the expectations for a compensated semimetal, and the corresponding effective masses are ∼mₑ, rather small compared to those of other BEDT-TTF salts. Apart from the case of the smallest Fermi-surface pocket, varying the M ion seems to have little effect on the overall Fermi-surface topology or on the effective masses. Despite the fact that all samples show quantum oscillations at low temperatures, indicative of Fermi liquid behavior, the sample and temperature dependence of the interlayer resistivity suggest that these systems are intrinsically inhomogeneous. It is thought that intrinsic tendency to disorder in the anions and/or the ethylene groups of the BEDT-TTF molecules leads to the coexistence of insulating and metallic states at low temperatures. A notional phase diagram is given for the general family of β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ salts

    Effects of electron correlations and chemical pressures on superconductivity of β''-type organic compounds

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    We investigate low-temperature electronic states of the series of organic conductors β'' - [bis(ethylenedithio)tetrathiafulvalene] 4[(H3O)M(C2O4)3] G, where M and G represent trivalent metalions and guest organic molecules, respectively. Our structural analyses reveal that the replacement of M and G give rise to systematic change in the cell parameters, especially in the b-axis length, which has a positive correlation with the superconducting transition temperature Tc. Analysis of temperature and magnetic field dependences of the electrical resistance including the Shubnikov–de Haas oscillations elucidates that the variation of charge disproportionation, the effective mass, and the number of itinerant carriers can be systematically explained by the change of the b-axis length. The changes of the transfer integrals induced by stretching/compressing the b axis are confirmed by the band calculation. We discuss that electron correlations in quarter-filled electronic bands lead to charge disproportionation and the possibility of a novel pairing mechanism of superconductivity mediated by charge degrees of freedom

    Radical-cation salt with novel BEDT-TTF packing motif containing tris(oxalato)germanate(IV)

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    The synthesis, crystal structure and resistivity of a new semiconducting BEDT-TTF radical-cation salt containing the tris(oxalato)germanate(IV) anion is reported. BEDT-TTF4[Ge(C2O4)3].0.5dichloromethane crystallizes in the space group P21/c, a = 18.322(7), b = 11.919(4), c = 32.746(11) Å, β = 105.797(5)°, V = 6881(4) Å3, T = 295(1) K, Z = 4. Electrical resistivity measurements show that BEDT-TTF4[Ge(C2O4)3].0.5dichloromethane is a semiconductor with an activation energy of 0.224 eV and room temperature resistivity of 212 Ω cm

    Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes

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    Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle with 100km arm lengths orbiting 2000km above the surface of the earth. It is hoped that the launch date will be in the late 2020s. Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and GW151226. Pre-DECIGO can detect 30M30M\sim 30M_\odot-30M_\odot BBH mergers up to redshift z30z\sim 30. The cumulative event rate is 1.8×105events yr1\sim 1.8\times 10^{5}\,{\rm events~yr^{-1}} in the Pop III origin model of BBHs like GW150914, and it saturates at z10z\sim 10, while in the primordial BBH (PBBH) model, the cumulative event rate is 3×104events yr1 \sim 3\times 10^{4}\,{\rm events~ yr^{-1}} at z=30z=30 even if only 0.1%0.1\% of the dark matter consists of PBHs, and it is still increasing at z=30z=30. In the Pop I/II model of BBHs, the cumulative event rate is (310)×105events yr1(3-10)\times10^{5}\,{\rm events~ yr^{-1}} and it saturates at z6z \sim 6. We present the requirements on orbit accuracy, drag free techniques, laser power, frequency stability, and interferometer test mass. For BBHs like GW150914 at 1Gpc, SNR90\sim 90 is achieved with the definition of Pre-DECIGO in the 0.011000.01-100Hz band. Pre-DECIGO can measure the mass spectrum and the zz-dependence of the merger rate to distinguish various models of BBHs like GW150914. Pre-DECIGO can also predict the direction of BBHs at z=0.1z=0.1 with an accuracy of 0.3deg2\sim 0.3\,{\rm deg}^2 and a merging time accuracy of 1\sim 1s at about a day before the merger so that ground-based GW detectors further developed at that time as well as electromagnetic follow-up observations can prepare for the detection of merger in advance. For intermediate mass BBHs at a large redshift z>10z > 10, the QNM frequency after the merger can be within the Pre-DECIGO band so that the ringing tail can also be detectable to confirm the Einstein theory of general relativity with SNR35\sim 35. [abridged]Comment: 17 pages, 10 figures, added some references, modifications to match the published version in PTE

    On the Complexity of Tree Edit Distance with Variables

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    In this paper, we propose tree edit distance with variables, which is an extension of the tree edit distance to handle trees with variables and has a potential application to measuring the similarity between mathematical formulas. We analyze the computational complexity of several variants of this model. In particular, we show that the problem is NP-complete for ordered trees. We also show for unordered trees that the problem of deciding whether or not the distance is 0 is graph isomorphism complete but can be solved in polynomial time if the maximum outdegree of input trees is bounded by a constant. We also present parameterized and exponential-time algorithms for ordered and unordered cases, respectively

    Stereoisomeric semiconducting radical cation salts of chiral bis(2-hydroxypropylthio)ethylenedithioTTF with tetrafluoroborate anions

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    The new chiral TTF-based donor molecule bis(2-hydroxypropylthio)ethylenedithiotetrathiafulvalene has produced enantiopure R,R and S,S radical cation salts with the tetrafluoroborate anion as well as the nearly isostructural meso/racemate mixture. The enantiopure R,R or S,S salts are both 1:1 semiconducting salts with activation energies of 0.19–0.24 eV, both crystallising in the orthorhombic space group C2221. The semiconducting salt containing both meso and racemic donor cations has a very similar crystal structure but crystallising in the monoclinic space group C2/c (β = 91.39°) with similar S⋯S interactions but a smaller activation energy of 0.15–0.17 eV. This is in contrast to previous families of this type where the disordered racemate has a larger activation energy than its enantiopure salts

    Tris(oxamide dioxime-κ2 N,N′)nickel(II) sulfate penta­hydrate

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    The asymmetric unit of the title compound, [Ni(C2H6N4O2)3]SO4·5H2O, contains two complex cations, two sulfate anions and ten lattice water mol­ecules. In both independent cations, the central NiII ion adopts a distorted octa­hedral coordination involving six imino N atoms of three bidentate oxamide dioxime ligands. The bulk structure is achieved by a three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds which inter­link the ionic partners and some water mol­ecules in such a manner that the lattice framework thus formed defines channels parallel to [100]. The other water mol­ecules are lodged inside these channels. Two of the ten water mol­ecules in the asymmetric unit are disordered over three sites, in 0.356 (3):0.324 (5):0.320 (5) and 0.247 (3):0.293 (6):0.460 (6) occupancy ratios, and one O atom of a sulfate ion is also disordered over two sites, with occupancies of 0.621 (5) and 0.379 (5)

    Magnetization Process of One-Dimensional Quantum Antiferromagnet: The Product Wavefunction Renormalization Group Approach

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    The product-wavefunction renormalization group method, which is a novel numerical renormalization group scheme proposed recently,is applied to one-dimensional quantum spin chains in a magnetic field. We draw the zero-temperature magnetization curve of the spin chains, which excellently agrees with the exact solution in the whole range of the field.Comment: 14 pages, LaTeX, 5 non-embedded figures, to be published in Physics Letters
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