1,035 research outputs found

    Indecomposable positive maps in low dimensional matrix algebras

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    AbstractWe classify a series of positive maps in low dimensional matrix algebras with respect to the degree of indecomposability and provide stronger indecomposable maps in Mn(). We also present a basic result about the atomic property

    Evidence for Bound Entangled States with Negative Partial Transpose

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    We exhibit a two-parameter family of bipartite mixed states ρbc\rho_{bc}, in a d⊗dd\otimes d Hilbert space, which are negative under partial transposition (NPT), but for which we conjecture that no maximally entangled pure states in 2⊗22\otimes 2 can be distilled by local quantum operations and classical communication (LQ+CC). Evidence for this undistillability is provided by the result that, for certain states in this family, we cannot extract entanglement from any arbitrarily large number of copies of ρbc\rho_{bc} using a projection on 2⊗22\otimes 2. These states are canonical NPT states in the sense that any bipartite mixed state in any dimension with NPT can be reduced by LQ+CC operations to an NPT state of the ρbc\rho_{bc} form. We show that the main question about the distillability of mixed states can be formulated as an open mathematical question about the properties of composed positive linear maps.Comment: Revtex, 19 pages, 2 eps figures. v2,3: very minor changes, submitted to Phys. Rev. A. v4: minor typos correcte

    Income or education, which has a stronger association with dental implant use in elderly people in Japan?

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    OBJECTIVES Although inequalities in dental implant use based on educational level have been reported, no study has used income as a proxy for the socioeconomic status. We examined: (i) income inequalities in implant use; and (ii) whether income or education has a stronger association with implant use in elder Japanese. METHODS In 2016, a self‐reported questionnaire was mailed to participants aged 65 years or older living across Japan as part of the ongoing Japan Gerontological Evaluation Study. We used data from 84,718 respondents having 19 or fewer teeth. After multiple imputation, multi‐level logistic regression estimated the association of dental implant use with equivalised income level and years of formal education. Confounders were age, sex, and density of dental clinics in the residential area. RESULTS 3.1% of respondents had dental implants. Percentages of dental implant use among the lowest (≀ 9 years) and highest (≄ 13 years) educational groups were 1.8 and 5.1, respectively, and among the lowest (0 < 12.2 ‘1,000 USD/year’) and highest (≄ 59.4 ‘1,000 USD/year’) income groups were 1.7 and 10.4, respectively. A fully adjusted model revealed that both income and education were independently associated with dental implant use. Odds ratios for implant use in the highest education and income groups were 2.13 [95% CI = 1.94–2.35] and 4.85 [95% CI = 3.78–6.22] compared with the lowest education and income groups, respectively. From a model with standardised variables, income showed slightly stronger association than education. CONCLUSION This study reveals a public health problem that even those with the highest education but low income might have limited accessibility to dental implant services

    Photo-production of neutral kaons on 12C in the threshold region

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    Kaon photo-production process on 12^{12}C has been studied by measuring neutral kaons in a photon energy range of 0.8−-1.1 GeV. Neutral kaons were identified by the invariant mass constructed from two charged pions emitted in the KS0→π+π−K^{0}_{S}\to\pi^{+}\pi^{-} decay channel. The differential cross sections as well as the integrated ones in the threshold photon energy region were obtained. The obtained momentum spectra were compared with a Spectator model calculation using elementary amplitudes of kaon photo-production given by recent isobar models. Present result provides, for the first time, the information on n(Îł,K0)Λn(\gamma,K^{0})\Lambda reaction which is expected to play an important role to construct models for strangeness production by the electromagnetic interaction. Experimental results show that cross section of 12C(Îł,K0)^{12}{\rm C}(\gamma,K^0) is of the same order to that of 12C(Îł,K+)^{12}{\rm C}(\gamma,K^+) and suggest that slightly backward K0K^0 angular distribution is favored in the Îłn→K0Λ\gamma n\to K^0\Lambda process.Comment: 6 pages, 8 figure

    Construction of 3⊗33\otimes 3 entangled edge states with positive partial transposes

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    We construct a class of 3⊗33\otimes 3 entangled edge states with positive partial transposes using indecomposable positive linear maps. This class contains several new types of entangled edge states with respect to the range dimensions of themselves and their partial transposes.Comment: 14 page

    Examining the associations between oral health and social isolation: A cross-national comparative study between Japan and England.

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    In Western countries, the most important part of the face in communication is the mouth, whereas it is the eyes in Asian countries; thus oral health could be more important in social interactions in Western countries. Our aim was to examine differences in the association between oral health status and social isolation among older people by comparing Japan and England. We used cross-sectional information obtained from adults aged 65+ in two ongoing prospective cohort studies: The Japan Gerontological Evaluation Study (JAGES, N = 120,195) and the English Longitudinal Study of Ageing (ELSA, N = 3,958). The dependent variable, social isolation score (SIS) was calculated from five factors (marital status, social support from children, social support from family, social support from friends, and social participation). The independent variables were self-reported number of remaining teeth (0, 1–9, 10–19, ≄20) and denture use (≄20 teeth, 10–19 teeth with denture, 10–19 teeth without denture, 0–9 teeth with denture, 0–9 teeth without denture), while the covariates in the model were: sex, age, educational attainment, self-rated health, number of comorbidities, household annual equivalized income, mental health status, daily living activities, and smoking status. We examined associations between oral health status and SIS by applying an ordered logit model by country. Compared to England, more Japanese participants were socially isolated (1.4% vs. 5.8%), but fewer were edentulous (13.1% vs. 7.7%). In both countries, poorer oral health further increased the odds of being socially isolated. Pooled analysis of the ordered logit model with an interaction term showed that the association of number of remaining teeth with SIS was stronger in edentulous participants and in England (odds ratio = 1.50, 95% Confidence interval:1.26–1.80). In both countries, oral health was associated with social isolation; this association could be stronger in England than in Japan

    Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

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    Photolysis (λ \u3e 543 nm) of 3-thienyldiazomethane (1), matrix isolated in Ar or N2 at 10 K, yields triplet 3-thienylcarbene (13) and α-thial-methylenecyclopropene (9). Carbene 13 was characterized by IR, UV/vis, and EPR spectroscopy. The conformational isomers of 3-thienylcarbene (s-E and s-Z) exhibit an unusually large difference in zero-field splitting parameters in the triplet EPR spectrum (|D/hc| = 0.508 cm–1, |E/hc| = 0.0554 cm–1; |D/hc| = 0.579 cm–1, |E/hc| = 0.0315 cm–1). Natural Bond Orbital (NBO) calculations reveal substantially differing spin densities in the 3-thienyl ring at the positions adjacent to the carbene center, which is one factor contributing to the large difference in D values. NBO calculations also reveal a stabilizing interaction between the sp orbital of the carbene carbon in the s-Z rotamer of 13 and the antibonding σ orbital between sulfur and the neighboring carbon—an interaction that is not observed in the s-E rotamer of 13. In contrast to the EPR spectra, the electronic absorption spectra of the rotamers of triplet 3-thienylcarbene (13) are indistinguishable under our experimental conditions. The carbene exhibits a weak electronic absorption in the visible spectrum (λmax = 467 nm) that is characteristic of triplet arylcarbenes. Although studies of 2-thienyldiazomethane (2), 3-furyldiazomethane (3), or 2-furyldiazomethane (4) provided further insight into the photochemical interconversions among C5H4S or C5H4O isomers, these studies did not lead to the spectroscopic detection of the corresponding triplet carbenes (2-thienylcarbene (11), 3-furylcarbene (23), or 2-furylcarbene (22), respectively)
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