14,649 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

    On Dirac-like Monopoles in a Lorentz- and CPT-violating Electrodynamics

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    We study magnetic monopoles in a Lorentz- and CPT-odd electrodynamical framework in (3+1) dimensions. This is the standard Maxwell model extended by means of a Chern-Simons-like term, bμF~μνAνb_\mu\tilde{F}^{\mu\nu}A_\nu (bμb_\mu constant), which respects gauge invariance but violates both Lorentz and CPT symmetries (as a consequence, duality is also lost). Our main interest concerns the analysis of the model in the presence of Dirac monopoles, so that the Bianchi identity no longer holds, which naively yields the non-conservation of electric charge. Since gauge symmetry is respected, the issue of charge conservation is more involved. Actually, the inconsistency may be circumvented, if we assume that the appearance of a monopole induces an extra electric current. The reduction of the model to (2+1) dimensions in the presence of both the magnetic sources and Lorentz-violating terms is presented. There, a quantization condition involving the scalar remnant of bμb_\mu, say, the mass parameter, is obtained. We also point out that the breaking of duality may be associated with an asymmetry between electric and magnetic sources in this background, so that the electromagnetic force experienced by a magnetic pole is supplemented by an extra term proportional to bμb_\mu, whenever compared to the one acting on an electric charge.Comment: 10 pages, no figures, typed in te

    Two-species fermion mixtures with population imbalance

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    We analyze the phase diagram of uniform superfluidity for two-species fermion mixtures from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) limit as a function of the scattering parameter and population imbalance. We find at zero temperature that the phase diagram of population imbalance versus scattering parameter is asymmetric for unequal masses, having a larger stability region for uniform superfluidity when the lighter fermions are in excess. In addition, we find topological quantum phase transitions associated with the disappearance or appearance of momentum space regions of zero quasiparticle energies. Lastly, near the critical temperature, we derive the Ginzburg-Landau equation, and show that it describes a dilute mixture of composite bosons and unpaired fermions in the BEC limit.Comment: 4 pages with 3 figures, accepted version to PR

    Aspectos da associação micorrízica em plantas forrageiras (Bauhinia cheilanta e Dolichos lablab - Fabacea): simbiose e eficiência no crescimento vegetal sob condições semi-áridas.

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    Os objetivos desse trabalho foram avaliar a condição micorrízica e identificar espécies de FMA presentes nas rizosfera das plantas forrageiras: mororó (Bauhinia cheilanta) e lablab (Dolichos lablab), em condições semi-áridas, e selecionar espécies de FMA eficientes em promover a sobrevivência, o crescimento e o teor nutricional de plantas forrageiras em dois tipos de solo representativos da região do vale do submédio São Francisco

    Karyotypic stability in asparagus (Asparagus officinalis L.) cultivars revealed by rDNA in situ Hybridization.

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    Four asparagus cultivars were cytologically studied by conventional staining and in situ hybridization, in order to evaluate both the variability among cultivars and the distribution pattern of 18S-25S rRNA genes. lhe mitotic and meiotic analysis with conventional chromosome staining did not show heteromorphisms or differences between cultivars. In situ hybridization with 18S and 25S rONA probes showed 6 chromosomes with 18S-25S rONA sites in the 4 studied genotypes. lhe New Jersey, Waltam Washington and G4X 14 cultivars presented 4 chromosomes with larger subterminal sites and 2 with interstitial sites of smaller size. In the Oeco cultivar, heteromorphism was verified in the size of the rONA sites, which were larger and subterminal in 3 chromosomes, and small and interstitial in 3 other chromosomes. lhe results suggest that asparagus cultivars may present only small differences in the number and distribution of rONA loci

    How hole defects modify vortex dynamics in ferromagnetic nanodisks

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    Defects introduced in ferromagnetic nanodisks may deeply affect the structure and dynamics of stable vortex-like magnetization. Here, analytical techniques are used for studying, among other dynamical aspects, how a small cylindrical cavity modify the oscillatory modes of the vortex. For instance, we have realized that if the vortex is nucleated out from the hole its gyrotropic frequencies are shifted below. Modifications become even more pronounced when the vortex core is partially or completely captured by the hole. In these cases, the gyrovector can be partially or completely suppressed, so that the associated frequencies increase considerably, say, from some times to several powers. Possible relevance of our results for understanding other aspects of vortex dynamics in the presence of cavities and/or structural defects are also discussed.Comment: 9 pages, 4 page

    Exactly Solvable Models of Interacting Spin-s Particles in one-dimension

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    We consider the exact solution of a many-body problem of spin-ss particles interacting through an arbitrary U(1) invariant factorizable SS-matrix. The solution is based on a unified formulation of the quantum inverse scattering method for an arbitrary (2s+1)(2s+1)-dimensional monodromy matrix. The respective eigenstates are shown to be given in terms of 2s2s creation fields by a general new recurrence relation. This allows us to derive the spectrum and the respective Bethe ansatz equations.Comment: 10 pages, plain late
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