6,623 research outputs found

    Violation of Bell's Inequalities with a Local Theory of Photons

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    We use a local theory of photons purely as particles to model the single-photon experiment proposed by Tan, Walls, and Collett. Like Tan et al. we are able to derive a violation of Bell's inequalities for photon counts coincidence measurements. Our local probabilistic theory does not use any specific quantum mechanical calculations.Comment: LaTeX, 11 pages, one figure (in LaTeX), submitted to Foundations of Physics Letter

    Entropy, diffusivity and the energy landscape of a water-like fluid

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    Molecular dynamics simulations and instantaneous normal mode (INM) analysis of a fluid with core-softened pair interactions and water-like liquid-state anomalies are performed to obtain an understanding of the relationship between thermodynamics, transport properties and the poten- tial energy landscape. Rosenfeld-scaling of diffusivities with the thermodynamic excess and pair correlation entropy is demonstrated for this model. The INM spectra are shown to carry infor- mation about the dynamical consequences of the interplay between length scales characteristic of anomalous fluids, such as bimodality of the real and imaginary branches of the frequency distribu- tion. The INM spectral information is used to partition the liquid entropy into two contributions associated with the real and imaginary frequency modes; only the entropy contribution from the imaginary branch captures the non-monotonic behaviour of the excess entropy and diffusivity in the anomalous regime of the fluid

    Association of socioeconomic status with inflammatory markers: a two cohort comparison.

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    OBJECTIVE: To assess the association between socioeconomic status (SES) and inflammatory markers using two different European population samples. METHODS: We used data from the CoLaus (N=6412, Lausanne, Switzerland) and EPIPorto (N=1205, Porto, Portugal) studies. Education and occupational position were used as indicators of socioeconomic status (SES). High-sensitivity C-reactive protein (hs-CRP) was available for both cohorts. Interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were available in CoLaus; leukocyte count and fibrinogen in EPIPorto. RESULTS: We showed that low SES was significantly associated with high inflammation in both studies. We also showed that behavioural factors contributed the most to SES differences in inflammation. In both studies the larger difference between the lowest and the highest SES was observed for hs-CRP. In the Swiss sample, a linear association between education and hs-CRP persisted after adjustment for all mediating factors and confounders considered (p for linear trend <0.001). CONCLUSION: Large social differences exist in inflammatory activity, in part independently from demographic and behavioural factors, chronic conditions and medication use. SES differences in inflammation are also similar in countries with different underlying socioeconomic conditions

    Composição bromatológica e digestibilidade aparente da parte aérea seca da mandioca na alimentação de tilápia-do-nilo.

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    O objetivo deste trabalho foi avaliar o efeito da secagem da parte aérea da mandioca, ao sol e à sombra, sobre a composição bromatológica e o coeficiente de digestibilidade aparente (CDA) de nutrientes, energia e aminoácidos para tilápia-do-nilo (Oreochromis niloticus). Não houve diferença entre os métodos de secagem para a composição bromatológica. O CDA da proteína bruta apresentou maior digestibilidade para a parte aérea seca à sombra. A secagem da parte aérea da mandioca à sombra permite maior conservação do conteúdo proteico e melhor digestibilidade aparente da fração proteica e aminoacídica para a tilápia-do-nilo

    Understanding stellar activity-induced radial velocity jitter using simultaneous K2 photometry and HARPS RV measurements

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    One of the best ways to improve our understanding of the stellar activity-induced signal in radial velocity (RV) measurements is through simultaneous high-precision photometric and RV observations. This is of prime importance to mitigate the RV signal induced by stellar activity and therefore unveil the presence of low-mass exoplanets. The K2 Campaign 7 and 8 field-of-views were located in the southern hemisphere, and provided a unique opportunity to gather unprecedented simultaneous high precision photometric observation with K2 and high-precision RV measurements with the HARPS spectrograph to study the relationship between photometric variability and RV jitter. We observed nine stars with different levels of activity; from quiet to very active. We probe the presence of any meaningful relation between measured RV jitter and the simultaneous photometric variation, and also other activity indicators (e.g. BIS, FWHM, logRHKlogR'_{HK}, and F8), by evaluating the strength and significance of the correlation between RVs and each indicator. We found that for the case of very active stars, strong and significant correlations exist between almost all the observables and measured RVs; however, for lower activity levels the correlations become random. Except for the F8 which its strong correlation with RV jitter persists over a wide range of stellar activity level, and thus our result suggests that F8 might be a powerful proxy for activity induced RV jitter. Moreover, we examine the capability of two state-of-the-art modeling techniques, namely the FF' method and SOAP2.0, in accurately predicting the RV jitter amplitude using the simultaneous photometric observation. We found that for the very active stars both techniques can reasonably well predict the amplitude of the RV jitter, however, at lower activity levels the FF' method underpredicts the RV jitter amplitude.Comment: 13 pages, 7 figures, 2 tables, accepted for publication in A&

    Optical Line Emission from z\sim6.8 Sources with Deep Constraints on Lyα\alpha Visibility

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    We analyze a sample of zz-dropout galaxies in the CANDELS GOODS South and UDS fields that have been targeted by a dedicated spectroscopic campaign aimed at detecting their Lyα\alpha line. Deep IRAC observations at 3.6 and 4.5 μ\mum are used to determine the strength of optical emission lines affecting these bands at z\sim6.5-6.9 in order to i) investigate possible physical differences between Lyα\alpha emitting and non-emitting sources; ii) constrain the escape fraction of ionizing photons; iii) provide an estimate of the specific star-formation rate at high redshifts. We find evidence of strong [OIII]+Hβ\beta emission in the average (stacked) SEDs of galaxies both with and without Lyα\alpha emission. The blue IRAC [3.6]-[4.5] color of the stack with detected Lyα\alpha line can be converted into a rest-frame equivalent width EW([OIII]+Hβ\beta)=1500440+530A˚^{+530}_{-440}\AA assuming a flat intrinsic stellar continuum. This strong optical line emission enables a first estimate of fesc_{esc}\lesssim20% on the escape fraction of ionizing photons from Lyα\alpha detected objects. The objects with no Lyα\alpha line show less extreme EW([OIII]+Hβ\beta)=520150+170A˚^{+170}_{-150}\AA suggesting different physical conditions of the HII regions with respect to Lyα\alpha-emitting ones, or a larger fesc_{esc}. The latter case is consistent with a combined evolution of fesc_{esc} and the neutral hydrogen fraction as an explanation of the lack of bright Lyα\alpha emission at z>>6. A lower limit on the specific star formation rate, SSFR>>9.1Gyr1Gyr^{-1} for Mstar=2×109MM_{star}=2 \times 10^9 M_{\odot} galaxies at these redshifts can be derived from the spectroscopically confirmed sample.Comment: 10 pages, 7 figures; The Astrophysical Journal in press; matched to the published versio

    Inequalities for dealing with detector inefficiencies in Greenberger-Horne-Zeilinger-type experiments

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    In this article we show that the three-particle GHZ theorem can be reformulated in terms of inequalities, allowing imperfect correlations due to detector inefficiencies. We show quantitatively that taking into accout those inefficiencies, the published results of the Innsbruck experiment support the nonexistence of local hidden variables that explain the experimental result.Comment: LaTeX2e, 9 pages, 3 figures, to appear in Phys. Rev. Let
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