9,660 research outputs found

    Galaxy clustering with photometric surveys using PDF redshift information

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    Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are Δz=0.1\Delta z=0.1, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.Comment: Matches the MNRAS published version. 19 pages, 19 Figure

    Synchronization of interconnected networks: the role of connector nodes

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    In this Letter we identify the general rules that determine the synchronization properties of interconnected networks. We study analytically, numerically and experimentally how the degree of the nodes through which two networks are connected influences the ability of the whole system to synchronize. We show that connecting the high-degree (low-degree) nodes of each network turns out to be the most (least) effective strategy to achieve synchronization. We find the functional relation between synchronizability and size for a given network-of-networks, and report the existence of the optimal connector link weights for the different interconnection strategies. Finally, we perform an electronic experiment with two coupled star networks and conclude that the analytical results are indeed valid in the presence of noise and parameter mismatches.Comment: Accepted for publication in Physical Review Letters. Main text: 5 pages, 4 figures. Supplemental material: 8 pages, 3 figure

    La aplicación de los gráficos en la didáctica de la traducción científico-técnica.

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    Los gráficos como sistema de transmisión de ideas cobran una especial importancia en el lenguaje científico-técnico, pues su utilización simplifica y cIarifica la comunicación cuando la información es compleja. El traductor que se enfrenta a textos con gráficos puede valerse de ellos para comprender mejor el texto. Del mismo modo, el profesor de traducción científico-técnica puede emplear los gráficos en la clase para hacer más claras las explicaciones y mejorar la comprensión por parte del alumnado.Graphics as a system of transmission of ideas takes a special importance in the scientific and technical language, since its use makes communication easier and clearer when information is complex. The transíator who faces texts with graphics can take advantage of them for a better comprehension of the text. In the same way, the teacher of scientific and technical transíation can use the graphics in class ir make te explanations clearer and improve the comprehension of the students. 145 Manuel Sevilla Mullos La aplicación de los gráficos en la didáctica de la traducción... Julia Sevilla Muño

    A class of Hamilton-Jacobi equations on Banach-Finsler manifolds

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    The concept of subdifferentiability is studied in the context of C1C^1 Finsler manifolds (modeled on a Banach space with a Lipschitz C1C^1 bump function). A class of Hamilton-Jacobi equations defined on C1C^1 Finsler manifolds is studied and several results related to the existence and uniqueness of viscosity solutions are obtained.Comment: 24 page

    Harmonically Trapped Quantum Gases

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    We solve the problem of a Bose or Fermi gas in dd-dimensions trapped by δ≤d% \delta \leq d mutually perpendicular harmonic oscillator potentials. From the grand potential we derive their thermodynamic functions (internal energy, specific heat, etc.) as well as a generalized density of states. The Bose gas exhibits Bose-Einstein condensation at a nonzero critical temperature TcT_{c} if and only if d+δ>2d+\delta >2, and a jump in the specific heat at TcT_{c} if and only if d+δ>4d+\delta >4. Specific heats for both gas types precisely coincide as functions of temperature when d+δ=2d+\delta =2. The trapped system behaves like an ideal free quantum gas in d+δd+\delta dimensions. For δ=0\delta =0 we recover all known thermodynamic properties of ideal quantum gases in dd dimensions, while in 3D for δ=\delta = 1, 2 and 3 one simulates behavior reminiscent of quantum {\it wells, wires}and{\it dots}, respectively.Comment: 14 pages including 3 figures and 3 table

    Electrochemical reduction of carbamazepine in ethanol and water solutions using a glassy carbon electrode

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    The electrochemical reduction of carbamazepine in ethanol and water using a glassy carbon electrode has been studied. In all experimental conditions of scan rate and concentration of carbamazepine an irreversible cathodic wave was observed by cyclic voltammetry (CV). Electrochemical parameters and a plausible EqC mechanism have been reported from the electrochemical measurements and digital simulation. The values of thermodynamic E1/2 were correlated with solvent polarity parameters that it can be interesting for biological, pharmaceutical and forensic purposes. Limits of Detection (LOD) for DPV are 1.1 and 9.0 g/mL (4.65x10-6 and 3.81x10-5 M) in ethanol and water, respectively. The precision and recoveries obtained for tablets and plasma samples showed that the method could be successfully used for analysis

    Cooper pairs as bosons

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    Although BCS pairs of fermions are known not to obey Bose-Einstein (BE) commutation relations nor BE statistics, we show how Cooper pairs (CPs), whether the simple original ones or the CPs recently generalized in a many-body Bethe-Salpeter approach, being clearly distinct from BCS pairs at least obey BE statistics. Hence, contrary to widespread popular belief, CPs can undergo BE condensation to account for superconductivity if charged, as well as for neutral-atom fermion superfluidity where CPs, but uncharged, are also expected to form.Comment: 8 pages, 2 figures, full biblio info adde
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