15,084 research outputs found

    Fundraising and vote distribution: a non-equilibrium statistical approach

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    The number of votes correlates strongly with the money spent in a campaign, but the relation between the two is not straightforward. Among other factors, the output of a ballot depends on the number of candidates, voters, and available resources. Here, we develop a conceptual framework based on Shannon entropy maximization and Superstatistics to establish a relation between the distributions of money spent by candidates and their votes. By establishing such a relation, we provide a tool to predict the outcome of a ballot and to alert for possible misconduct either in the report of fundraising and spending of campaigns or on vote counting. As an example, we consider real data from a proportional election with 63236323 candidates, where a detailed data verification is virtually impossible, and show that the number of potential misconducting candidates to audit can be reduced to only nine

    Giant planets around two intermediate-mass evolved stars and confirmation of the planetary nature of HIP67851 c

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    Precision radial velocities are required to discover and characterize planets orbiting nearby stars. Optical and near infrared spectra that exhibit many hundreds of absorption lines can allow the m/s precision levels required for such work. However, this means that studies have generally focused on solar-type dwarf stars. After the main-sequence, intermediate-mass stars (former A-F stars) expand and rotate slower than their progenitors, thus thousands of narrow absorption lines appear in the optical region, permitting the search for planetary Doppler signals in the data for these types of stars. We present the discovery of two giant planets around the intermediate-mass evolved star HIP65891 and HIP107773. The best Keplerian fit to the HIP65891 and HIP107773 radial velocities leads to the following orbital parameters: P=1084.5 d; mb_bsinii = 6.0 Mjup_{jup}; ee=0.13 and P=144.3 d; mb_bsinii = 2.0 Mjup_{jup}; ee=0.09, respectively. In addition, we confirm the planetary nature of the outer object orbiting the giant star HIP67851. The orbital parameters of HIP67851c are: P=2131.8 d, mc_csinii = 6.0 Mjup_{jup} and ee=0.17. With masses of 2.5 M_\odot and 2.4 M_\odot HIP65891 and HIP107773 are two of the most massive stars known to host planets. Additionally, HIP67851 is one of five giant stars that are known to host a planetary system having a close-in planet (a<a < 0.7 AU). Based on the evolutionary states of those five stars, we conclude that close-in planets do exist in multiple systems around subgiants and slightly evolved giants stars, but probably they are subsequently destroyed by the stellar envelope during the ascent of the red giant branch phase. As a consequence, planetary systems with close-in objects are not found around horizontal branch stars.Comment: Accepted for publication in A&

    Experimental Observation of Environment-induced Sudden Death of Entanglement

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    We demonstrate the difference between local, single-particle dynamics and global dynamics of entangled quantum systems coupled to independent environments. Using an all-optical experimental setup, we show that, while the environment-induced decay of each system is asymptotic, quantum entanglement may suddenly disappear. This "sudden death" constitutes yet another distinct and counter-intuitive trait of entanglement.Comment: 4 pages, 4 figure

    Seismic strengthening of beam-column joints with multidirectional CFRP laminates

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    An experimental program was carried out to analyse the potentialities of a technique based on the use of multidirectional CFRP laminates (MDL-CFRP) for the seismic repair and strengthening of reinforced concrete (RC) beam-column joints. This experimental program comprises cyclic tests on three full-scale RC joints, representative of interior beam-column connections in buildings. The joints were initially submitted to a cyclic test inducing a damage pattern representative of a seismic event. Subsequently, they were repaired and strengthened with MDL-CFRP. The strengthened joints were then tested for the same loading history of the original ones up to their failure. The adopted strengthening technique uses the MDL-CFRP that are simultaneously glued and anchored to the concrete surfaces. This technique is called Mechanically Fastened and Externally Bonded Reinforcement (MF-EBR). In the present study, the effectiveness of two different strengthening configurations was investigated. The tests are described and the main results are presented and analyzed

    Association of mid-infrared solar plages with Calcium K line emissions and magnetic structures

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    Solar mid-IR observations in the 8-15 micrometer band continuum with moderate angular resolution (18 arcseconds) reveal the presence of bright structures surrounding sunspots. These plage-like features present good association with calcium CaII K1v plages and active region magnetograms. We describe a new optical setup with reflecting mirrors to produce solar images on the focal plane array of uncooled bolometers of a commercial camera preceded by germanium optics. First observations of a sunspot on September 11, 2006 show a mid-IR continuum plage exhibiting spatial distribution closely associated with CaII K1v line plage and magnetogram structures. The mid-IR continuum bright plage is about 140 K hotter than the neighboring photospheric regions, consistent with hot plasma confined by the magnetic spatial structures in and above the active regionComment: 5 pages, 4 figures. Accepted by PAS

    An eccentric companion at the edge of the brown dwarf desert orbiting the 2.4 Msun giant star HIP67537

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    We report the discovery of a substellar companion around the giant star HIP67537. Based on precision radial velocity measurements from CHIRON and FEROS high-resolution spectroscopic data, we derived the following orbital elements for HIP67537b\,b: mb_bsinii = 11.11.1+0.4^{+0.4}_{-1.1} Mjup_{\rm {\tiny jup}}, aa = 4.90.13+0.14^{+0.14}_{-0.13} AU and ee = 0.590.02+0.05^{+0.05}_{-0.02}. Considering random inclination angles, this object has \gtrsim 65% probability to be above the theoretical deuterium-burning limit, thus it is one of the few known objects in the planet to brown-dwarf transition region. In addition, we analyzed the Hipparcos astrometric data of this star, from which we derived a minimum inclination angle for the companion of \sim 2 deg. This value corresponds to an upper mass limit of \sim 0.3 M_\odot, therefore the probability that HIP67537b\,b is stellar in nature is \lesssim 7%. The large mass of the host star and the high orbital eccentricity makes HIP67537b\,b a very interesting and rare substellar object. This is the second candidate companion in the brown dwarf desert detected in the sample of intermediate-mass stars targeted by the EXPRESS radial velocity program, which corresponds to a detection fraction of ff = 1.60.5+2.0^{+2.0}_{-0.5}%. This value is larger than the fraction observed in solar-type stars, providing new observational evidence of an enhanced formation efficiency of massive substellar companions in massive disks. Finally, we speculate about different formation channels for this object.Comment: Accepted for publication to A&

    Search for associations containing young stars (SACY). V. Is multiplicity universal? Tight multiple systems

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    Context: Dynamically undisrupted, young populations of stars are crucial to study the role of multiplicity in relation to star formation. Loose nearby associations provide us with a great sample of close (<<150 pc) Pre-Main Sequence (PMS) stars across the very important age range (\approx5-70 Myr) to conduct such research. Aims: We characterize the short period multiplicity fraction of the SACY (Search for Associations Containing Young stars) accounting for any identifiable bias in our techniques and present the role of multiplicity fractions of the SACY sample in the context of star formation. Methods: Using the cross-correlation technique we identified double-lined spectroscopic systems (SB2), in addition to this we computed Radial Velocity (RV) values for our subsample of SACY targets using several epochs of FEROS and UVES data. These values were used to revise the membership of each association then combined with archival data to determine significant RV variations across different data epochs characteristic of multiplicity; single-lined multiple systems (SB1). Results: We identified 7 new multiple systems (SB1s: 5, SB2s: 2). We find no significant difference between the short period multiplicity fraction (FmF_\mathrm{m}) of the SACY sample and that of nearby star forming regions (\approx1-2 Myr) and the field (FmF_\mathrm{m}\leq10%) both as a function of age and as a function of primary mass, M1M_1, in the ranges PP [1:200 day] and M2M_2 [0.08 MM_{\odot}-M1 M_1]. Conclusions: Our results are consistent with the picture of universal star formation, when compared to the field and nearby star forming regions (SFRs). We comment on the implications of the relationship between increasing multiplicity fraction with primary mass, within the close companion range, in relation to star formation.Comment: 14 pages, 18 figures, published, A&A http://dx.doi.org/10.1051/0004-6361/20142385

    Estimativas de parâmetros genéticos e fenotípicos em nível de indivíduo em populações segregantes de feijoeiro-comum.

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    O objetivo desse trabalho foi estimar os parâmetros genéticos e fenotípicos, em nível de indivíduo, de populações segregantes de feijoeiro-comum, grupo carioca, para caracteres de escurecimento e produção de grãos.CONAF

    π0γγ\pi^0\to\gamma^*\gamma transition form factor within Light Front Quark Model

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    We study the transition form factor of π0γγ\pi^0\to\gamma^* \gamma as a function of the momentum transfer Q2Q^2 within the light-front quark model (LFQM). We compare our result with the experimental data by BaBar as well as other calculations based on the LFQM in the literature. We show that our predicted form factor fits well with the experimental data, particularly those at the large Q2Q^2 region.Comment: 11 pages, 4 figures, accepted for publication in PR
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