8,020 research outputs found

    Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of κ\kappa-(BEDT-TTF)2X_2X

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    We show that the anisotropy of the effective spin model for the dimer Mott insulator phase of κ\kappa-(BEDT-TTF)2X_2X salts is dramatically different from that of the underlying tight-binding model. Intra-dimer quantum interference results in a model of coupled spin chains, where frustrated interchain interactions suppress long-range magnetic order. Thus, we argue, the "spin liquid" phase observed in some of these materials is a remnant of the Tomonaga-Luttinger physics of a single chain. This is consistent with previous experiments and resolves some outstanding puzzles. An erratum [Phys. Rev. Lett. 120, 199901 (2018).] is added as an appendix.Comment: Accepted by PRL, 6 pages, 5 figure

    New two-colour light curves of Q0957+561: time delays and the origin of intrinsic variations

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    We extend the gr-band time coverage of the gravitationally lensed double quasar Q0957+561. New gr light curves permit us to detect significant intrinsic fluctuations, to determine new time delays, and thus to gain perspective on the mechanism of intrinsic variability in Q0957+561. We use new optical frames of Q0957+561 in the g and r passbands from January 2005 to July 2007. These frames are part of an ongoing long-term monitoring with the Liverpool robotic telescope. We also introduce two photometric pipelines that are applied to the new gr frames of Q0957+561. The transformation pipeline incorporates zero-point, colour, and inhomogeneity corrections to the instrumental magnitudes, so final photometry to the 1-2% level is achieved for both quasar components. The two-colour final records are then used to measure time delays. The gr light curves of Q0957+561 show several prominent events and gradients, and some of them (in the g band) lead to a time delay between components of 417 +/- 2 d (1 sigma). We do not find evidence of extrinsic variability in the light curves of Q0957+561. We also explore the possibility of a delay between a large event in the g band and the corresponding event in the r band. The gr cross-correlation reveals a time lag of 4.0 +/- 2.0 d (1 sigma; the g-band event is leading) that confirms a previous claim of the existence of a delay between the g and r band in this lensed quasar. The time delays (between quasar components and between optical bands) from the new records and previous ones in similar bands indicate that most observed variations in Q0957+561 (amplitudes of about 100 mmag and timescales of about 100 d) are very probably due to reverberation within the gas disc around the supermassive black hole.Comment: 13 pages, 9 figures. Accepted for publication in A&

    Endobranding como resultado da gestão de pessoas e de design

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    Estudos sobre branding mostram que as marcas devem ser criadas de dentro para fora, isto é, do ambiente organizacional interno para o mercado. Da fundação da organização, criação de filosofia, valores, missão e visão ao alcance à expansão de mercados e consolidação da marca, seus colaboradores determinam a qualidade na oferta de produtos e serviços e a entrega ou não da chamada promessa da marca. Este argo objeva discur o termo endobranding (gestão interna de marcas), como resultante da interação entre as áreas de gestão de pessoas e gestão de design. A gestão de pessoas, por administrar o capital intelectual da empresa e corresponder ao canal de ligação entre organização e colaboradores. A gestão de design, por fomentar a cultura de projeto, inovação e lidar com fatores simbólicos, além de responder pelo valor percebido da marca, junto a todos os seus públicos de interesse. O estudo se uliza de pesquisa qualitava, bibliográfica e aplicada, dividida em três fases: na primeira, faz análises diacrônica e sincrônica sobre gestão de pessoas, gestão de design e branding. Na segunda fase, realiza revisão e críca literária para a definição conceitual destas áeras. Na terceira fase, exibe os resultados. Dentre estes, endobranding se apresenta como auxílio à reputação corporava, diminuindo a distância entre a verdadeira idendade da organização e como ele pode ser percebida por seus clientes. Além disto, também contribui para a compreensão do público interno como promotor da marca.ABSTRACT: Studies show that branding brands must be created from the inside out, the internal organizational environment for the market . The foundation of the organizaton , creaton of philosophy, values , mission and vision to reach to market expansion and consolidaton of the brand , its employees determine the quality in the provision of products and services and the delivery of the call or not brand promise . This article discusses the term endobranding ( internal branding ), as resulting from the interacton between the areas of people management and design management . People management for managing the intellectual capital of the company and match the link between organizaton and employees canal. The design management by fostering a culture of design, innovaton and deal with symbolic factors , in addition to responding to the perceived value of the brand, along with all its stakeholders . The study uses qualitative, literature and applied research, divided into three phases: firs , diachronic and synchronic analysis is about managing people , managing design and branding . In the second phase , performs review and literary criticism to the conceptual definition of these Aeras . In the third phase, displays the results. Among these, endobranding is presented as an aid to corporate reputation, decreasing the distance between the true identity of the organization and how it can be perceived by its customers . Moreover, it also contributes to the understanding of the internal public as a promoter of the brand.info:eu-repo/semantics/publishedVersio

    Fluctuation diagnostics of the electron self-energy: Origin of the pseudogap physics

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    We demonstrate how to identify which physical processes dominate the low-energy spectral functions of correlated electron systems. We obtain an unambiguous classification through an analysis of the equation of motion for the electron self-energy in its charge, spin and particle-particle representations. Our procedure is then employed to clarify the controversial physics responsible for the appearance of the pseudogap in correlated systems. We illustrate our method by examining the attractive and repulsive Hubbard model in two-dimensions. In the latter, spin fluctuations are identified as the origin of the pseudogap, and we also explain why d−d-wave pairing fluctuations play a marginal role in suppressing the low-energy spectral weight, independent of their actual strength.Comment: 6 pages, 2 figures + 4 pages supplementar

    Short-timescale Fluctuations in the Difference Light Curves of QSO 0957+561A,B: Microlensing or Noise?

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    From optical R band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (about 330 days of overlap between the time-shifted light curve for the A image and the magnitude-shifted light curve for the B image). We observed noisy behaviours around the zero line and no short-timescale events (with a duration of months), where the term event refers to a prominent feature that may be due to microlensing or another source of variability. Only one event lasting two weeks and rising - 33 mmag was found. Measured constraints on the possible microlensing variability can be used to obtain information on the granularity of the dark matter in the main lensing galaxy and the size of the source. In addition, one can also test the ability of the observational noise to cause the rms averages and the local features of the difference signals. We focused on this last issue. The combined photometries were related to a process consisting of an intrinsic signal plus a Gaussian observational noise. The intrinsic signal has been assumed to be either a smooth function (polynomial) or a smooth function plus a stationary noise process or a correlated stationary process. Using these three pictures without microlensing, we derived some models totally consistent with the observations. We finally discussed the sensitivity of our telescope (at Teide Observatory) to several classes of microlensing variability.Comment: MNRAS, in press (LaTeX, 14 pages, 22 eps figures

    Conceptual design of an orbital propellant transfer experiment. Volume 2: Study results

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    The OTV configurations, operations and requirements planned for the period from the 1980's to the 1990's were reviewed and a propellant transfer experiment was designed that would support the needs of these advanced OTV operational concepts. An overall integrated propellant management technology plan for all NASA centers was developed. The preliminary cost estimate (for planning purposes only) is 56.7M,ofwhichapproximately56.7 M, of which approximately 31.8 M is for shuttle user costs

    Evaluation of two commercially available rumen buffers derived from calcified seaweed for grazing dairy cows: Pilot trial in commercial farms

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    Los productos a base de algas marinas calcificadas (CS) se han propuesto como un tampón de pH ruminal alternativo al bicarbonato de sodio. Se ha reportado que el magnesio puede ayudar en el control del pH ruminal, especialmente las formas naturales marinas. Evaluamos la capacidad amortiguadora del pH del rumen y la producción y composición de la leche de dos CS: Acid Buf (AB) y M12 (un CS natural enriquecido con magnesio marino), en vacas lecheras en pastoreo en un diseño de cuadrado latino replicado que involucró 2 granjas con rebaños lecheros en buen estado sanitario y de salud, 2 suplementos y 4 periodos de evaluación de un mes cada uno. Vacas lecheras Holstein Friesian se alimentaron con una ración parcial mixta (PMR) y se suplementaron durante cuatro períodos de 30 días cada uno con AB o M12. Se midió la producción total y la composición de la leche en cada granja y cinco vacas en cada rebaño recibieron bolos ruminales para monitorear el pH ruminal, permitiéndonos identificar y monitorear eventos de acidosis ruminal subaguda total (SARA) (es decir = 2 h con pH < 5.8). El pH promedio durante el período experimental fue 2% mayor (p < 0,05) y el número de eventos SARA por vaca fue menor (p = 0,007) para vacas suplementadas con M12 en comparación con AB. Considerando solo las vacas que desarrollaron eventos SARA, M12 tendió (p = 0,068) a reducir el número de eventos de SARA y su duración en comparación con aquellas vacas suplementadas con AB. La producción y composición de la leche fueron similares entre ambos tampones ruminales en todos los períodos
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