430 research outputs found

    Exploiting quantum parallelism of entanglement for a complete experimental quantum characterization of a single qubit device

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    We present the first full experimental quantum tomographic characterization of a single-qubit device achieved with a single entangled input state. The entangled input state plays the role of all possible input states in quantum parallel on the tested device. The method can be trivially extended to any n-qubits device by just replicating the whole experimental setup n times.Comment: 4 pages in revtex4 with 4 eps figure

    Periastron shift in Weyl class spacetimes

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    The periastron position advance for geodesic motion in axially symmetric solutions of the Einstein field equations belonging to the Weyl class of vacuum solutions is investigated. Explicit examples corresponding to either static solutions (single Chazy-Curzon, Schwarzschild and a pair of them), or stationary solution (single rotating Chazy-Curzon and Kerr black hole) are discussed. The results are then applied to the case of S2-SgrA∗^* binary system of which the periastron position advance will be soon measured with a great accuracy.Comment: To appear on General Relativity and Gravitation, vol. 37, 200

    On Proper Polynomial Maps of C2.\mathbb{C}^2.

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    Two proper polynomial maps f1,f2 ⁣:C2⟶C2f_1, f_2 \colon \mathbb{C}^2 \longrightarrow \mathbb{C}^2 are said to be \emph{equivalent} if there exist Ί1,Ί2∈Aut(C2)\Phi_1, \Phi_2 \in \textrm{Aut}(\mathbb{C}^2) such that f2=Ί2∘f1∘Ί1f_2=\Phi_2 \circ f_1 \circ \Phi_1. We investigate proper polynomial maps of arbitrary topological degree d≄2d \geq 2 up to equivalence. Under the further assumption that the maps are Galois coverings we also provide the complete description of equivalence classes. This widely extends previous results obtained by Lamy in the case d=2d=2.Comment: 15 pages. Final version, to appear in Journal of Geometric Analysi

    Trait interactions effects on tropical tree demography depend on the environmental context

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    Although functional traits are defined based on their impact on demographic parameters, trait-demography relationships are often reported as weak. These weak relationships might be due to disregarding trait interactions and environmental contexts, which should modulate species trait-demography relationships. We applied different models, including boosted regression tree (BRT) models, to investigate changes in the relationship between traits and demographic rates of tropical tree species in plots along an elevational gradient and among time intervals between censuses, analyzing the effect of a strong drought event. Based on a large dataset of 18,000 tree individuals from 133 common species, distributed among twelve 1-ha plots (habitats) in the Atlantic Forest (Brazil), we evaluated how trait interactions and the environmental context influence the demographic rates (growth, mortality, and recruitment). Functional traits, trait-trait, and trait-habitat interactions predicted demography with a good fit through either BRTs or linear mixed-models. Changes in growth rates were best related to size (diameter), and mortality rates to habitats, while changes in recruitment rates were best related to the specific leaf area. Moreover, the influence of traits differed among time intervals, and for demographic parameters, habitat affected growth and mortality by interacting with diameter. Here, we provide evidence that trait-demography relationships can be improved when considering the environmental context (space and time) and trait interactions to cope with the complexity of changes in the demography of tropical tree communities. Thus, to expand predictions of demography based on functional traits, we show that it is useful to fully incorporate the concept of multiple trait-fitness optima, resulting from trait interactions in different habitats and growth conditions.We thank the Brazilian National Research Council (CNPq) and the Coordination for the Improvement of Higher Education Personnel (CAPES) for the scholarships conceded to the first author (CNPq 141781/2016-5 and CAPES 88881.189491/2018-01) and for the productivity fellowship to FAMS (CNPq 310168/2018-0). This study was financed by research funding of the projects: “Functional Gradient” (Biota/FAPESP 03/12595-7), “PELD/BIOTA” and “ECOFOR” (Processes 2012/51509-8 and 2012/51872-5, within the BIOTA/FAPESP Program), “EcoSpace” (Edital Universal CNPq 459941/2014-3), “Sustainable Landscapes Brazil” project (US Forest Service, USAID, US Department of State and EMBRAPA), and “Sustainable Landscapes” (NASA-Goddard). This study was also supported by CNPq (PELD CNPq 403710/2012-0), British Natural Environment Research Council/NERC (NE/K016431/1) and FAPESP as part of a doctoral fellowship (FAPESP 11/11604-0). CPC was financed by the Estonian Research Council (PSG293)

    On the Completeness of the Set of Classical W-Algebras Obtained from DS Reductions

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    We clarify the notion of the DS --- generalized Drinfeld-Sokolov --- reduction approach to classical W{\cal W}-algebras. We first strengthen an earlier theorem which showed that an sl(2)sl(2) embedding S⊂G{\cal S}\subset {\cal G} can be associated to every DS reduction. We then use the fact that a \W-algebra must have a quasi-primary basis to derive severe restrictions on the possible reductions corresponding to a given sl(2)sl(2) embedding. In the known DS reductions found to date, for which the \W-algebras are denoted by WSG{\cal W}_{\cal S}^{\cal G}-algebras and are called canonical, the quasi-primary basis corresponds to the highest weights of the sl(2)sl(2). Here we find some examples of noncanonical DS reductions leading to \W-algebras which are direct products of WSG{\cal W}_{\cal S}^{\cal G}-algebras and `free field' algebras with conformal weights Δ∈{0,12,1}\Delta \in \{0, {1\over 2}, 1\}. We also show that if the conformal weights of the generators of a W{\cal W}-algebra obtained from DS reduction are nonnegative Δ≄0\Delta \geq 0 (which isComment: 48 pages, plain TeX, BONN-HE-93-14, DIAS-STP-93-0

    Mineralogical, petrographic and chemical analyses for the study of the canvas "Cristo alla Colonna" from Cosenza, Italy : a case study

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    A multi-technique study on materials used for the painting "Cristo alla Colonna" by Luigi Bria (private collection, Cosenza, Italy) was carried out for the first time during the restoration plan. Pigments, binder media and raw materials used for the application of ground and priming layers were studied using optical (OM) and electronic microscopy equipped with energy dispersive spectroscopy qualitative microanalysis (SEM-EDS), infrared spectroscopy (FTIR) and gas chromatography coupled with mass spectrometry (GC/MS). The goal of this study was to characterize this canvas and to set up a scientific aid and guide for its restoration, taking into account the, severe damage not exclusively due to natural decay processes. Our data can provide information about historical and stylistic background as well as advises for correct planning of the cleaning procedures. Riassunto - II dipinto su tela "Cristo alla Colonna", opera di Luigi Bria (collezione privata, Cosenza, Italia), \ue8 stato sottoposto, durante le fasi di restauro, per la prima volta ad indagine strumentale tramite varie tecniche analitiche. I pigmenti, i leganti ed altri materiali utilizzati per la sua realizzazione sono stati analizzati tramite microscopia ottica (OM), microscopia elettronica e microanalisi tramite spettrometria a dispersione di energia (SEM-EDS), spettroscopia infrarossa (FTIR) e gascromatografia accoppiata spettrometria di massa (CG/MS). Lo scopo del lavoro \ue8 stato quello di offrire una caratterizzazione dell'opera pittorica, nonch\ue9 fornire un supporto scientifico ad un un corretto intervento di restauro su un'opera fortemente degradata. I risultati hanno permesso di fornire informazioni di natura storico-artistico nonch\ue9 informazioni utili ad un corretto intervento di pulitura della tela oggetto di questo studio

    A Note on Domain Walls and the Parameter Space of N=1 Gauge Theories

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    We study the spectrum of BPS domain walls within the parameter space of N=1 U(N) gauge theories with adjoint matter and a cubic superpotential. Using a low energy description obtained by compactifying the theory on R^3 x S^1, we examine the wall spectrum by combining direct calculations at special points in the parameter space with insight drawn from the leading order potential between minimal walls, i.e those interpolating between adjacent vacua. We show that the multiplicity of composite BPS walls -- as characterised by the CFIV index -- exhibits discontinuities on marginal stability curves within the parameter space of the maximally confining branch. The structure of these marginal stability curves for large N appears tied to certain singularities within the matrix model description of the confining vacua.Comment: 33 pages, LaTeX, 6 eps figures; v2: references adde

    The Vega debris disc: A view from Herschel

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    We present five band imaging of the Vega debris disc obtained using the Herschel Space Observatory. These data span a wavelength range of 70-500 mu m with full-width half-maximum angular resolutions of 5.6-36.9 ''. The disc is well resolved in all bands, with the ring structure visible at 70 and 160 mu m. Radial profiles of the disc surface brightness are produced, and a disc radius of 11 '' (similar to 85AU) is determined. The disc is seen to have a smooth structure thoughout the entire wavelength range, suggesting that the disc is in a steady state, rather than being an ephemeral structure caused by the recent collision of two large planetesimals

    Virgin olive oil and health: summary of the III international conference on virgin olive oil and health consensus report, JAEN (Spain) 2018

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    The Mediterranean diet is considered as the foremost dietary regimen and its adoption is associated with the prevention of degenerative diseases and an extended longevity. The preeminent features of the Mediterranean diet have been agreed upon and the consumption of olive oil stands out as the most peculiar one. Indeed, the use of olive oil as the nearly exclusive dietary fat is what mostly characterizes the Mediterranean area. Plenty of epidemiological studies have correlated that the consumption of olive oil was associated with better overall health. Indeed, extra virgin olive oil contains (poly)phenolic compounds that are being actively investigated for their purported biological and pharma-nutritional properties. On 18 and 19 May 2018, several experts convened in Jaen (Spain) to discuss the most recent research on the benefits of olive oil and its components. We reported a summary of that meeting (reviewing several topics related to olive oil, not limited to health) and concluded that substantial evidence is accruing to support the widespread opinion that extra virgin olive oil should, indeed, be the fat of choice when it comes to human health and sustainable agronomy
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