12,445 research outputs found

    Some properties of two Nambu--Jona-Lasinio -type models with inputs from lattice QCD

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    We investigate the phase diagram of the so-called Polyakov--Nambu--Jona-Lasinio (PNJL) model at finite temperature and nonzero chemical potential. The calculations are performed in the light and strange quark sectors (uu, dd, ss), which includes the 't Hooft instanton induced interaction term that breaks the axial symmetry, and the quarks are coupled to the (spatially constant) temporal background gauge field. On one hand, a special attention is payed to the critical end point (CEP). The strength of the flavor-mixing interaction alters the CEP location, since when it becomes weaker the CEP moves to low temperatures and can even disappear. On the other hand, we also explore the connection between QCD, a nonlocal Nambu--Jona-Lasinio type model and the Landau gauge gluon propagator. Possible links between the quenched gluon propagator and low energy hadronic phenomenology are investigated.Comment: Contribution to the International Meeting "Excited QCD", Peniche, Portugal, 06 - 12 May 201

    Comportamento de híbridos de coqueiro nos Tabuleiros Costeiros do Piauí.

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    Com o objetivo de avaliar o comportamento de híbridos de coqueiro nas condições de clima e solo dos Tabuleiros Costeiros do Piauí, conduziu-se um experimento no Campo Experimental da Embrapa Meio-Norte em Parnaíba-PI, no período de 2002 a 2004. Utilizou-se o delineamento experimental de blocos ao acaso, com sete tratamentos e quatro repetições. Os tratamentos foram constituídos por cinco híbridos entre coqueiro-anão e coqueiro-gigante: AAG x GBrPF, AVG x GBrPF, AVeJ x GBrRN, AAG x GOA e AVG x GOA) e os dois parentais (GBrRN e AVeJ) como testemunha. As características vegetativas, avaliadas semestralmente, foram o número de folhas vivas (NFV) emitidas (NFE), e as reprodutivas, avaliadas mensalmente, foram o número de inflorescências emitidas (NIE), número de flores femininas por inflorescência (NFFI) e número de frutos colhidos/planta (NFC). Os híbridos AAG x GBrPF; AVG x GBrP e AVG x GOA apresentam maior potencial de adaptação às condições edafoclimáticas dos Tabuleiros Costeiros do Piauí.bitstream/item/35881/1/BP61.pd

    Comportamento de cultivares de coqueiro-anão nos Tabuleiros Costeiros do Piauí.

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    bitstream/CPAMN-2009-09/20331/1/BOLP60.pd

    Phase Coherent Precessional Magnetization Reversal in Micro-scopic Spin Valve Elements

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    We study the precessional switching of the magnetization in microscopic spin valve cells induced by ultra short in-plane hard axis magnetic field pulses. Stable and highly efficient switching is monitored following pulses as short as 140 ps with energies down to 15 pJ. Multiple application of identical pulses reversibly toggles the cell's magnetization be-tween the two easy directions. Variations of pulse duration and amplitude reveal alter-nating regimes of switching and non-switching corresponding to transitions from in-phase to out-of-phase excitations of the magnetic precession by the field pulse. In the low field limit damping becomes predominant and a relaxational reversal is found allowing switching by hard axis fields below the in-plane anisotropy field threshold.Comment: 17 pages, 4 figure

    Atypical Presentations of Hearing Loss in Patients with Acoustic Neuroma

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    A hipoacúsia neurosensorial unilateral e progressiva é uma das principais manisfestações audiológicas dos doentes com diagnóstico de neurinoma do acústico, estando no entanto descritas outras formas de apresentação. Dos 43 doentes com diagnóstico de neurinoma do acústico, tratados pela equipa de otoneurocirurgia entre 1997 e 2003, identificamos 88,5% com hipoacústica neurosensorial unilateral, 4,6% como hipoacústica neurosensorial súbita, 4,6% com audição simétrica e 2,3% com audição "normal". Estes dados revelam a existência de três formas incomuns de apresentação dos neurinomas, facto que deve levar os otorrinolaringologistas a manterem um elevado grau de alerta perante doentes com queixas que possam sugerir, de algum modo, a presença de neurinoma do acústico

    Evidence for a spectroscopic direct detection of reflected light from 51 Peg b

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    The detection of reflected light from an exoplanet is a difficult technical challenge at optical wavelengths. Even though this signal is expected to replicate the stellar signal, not only is it several orders of magnitude fainter, but it is also hidden among the stellar noise. We apply a variant of the cross-correlation technique to HARPS observations of 51 Peg to detect the reflected signal from planet 51 Peg b. Our method makes use of the cross-correlation function of a binary mask with high-resolution spectra to amplify the minute planetary signal that is present in the spectra by a factor proportional to the number of spectral lines when performing the cross correlation. The resulting cross-correlation functions are then normalized by a stellar template to remove the stellar signal. Carefully selected sections of the resulting normalized CCFs are stacked to increase the planetary signal further. The recovered signal allows probing several of the planetary properties, including its real mass and albedo. We detect evidence for the reflected signal from planet 51 Peg b at a significance of 3\sigma_noise. The detection of the signal permits us to infer a real mass of 0.46^+0.06_-0.01 M_Jup (assuming a stellar mass of 1.04\;M_Sun) for the planet and an orbital inclination of 80^+10_-19 degrees. The analysis of the data also allows us to infer a tentative value for the (radius-dependent) geometric albedo of the planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 \pm 0.3 R_Jup for a signal amplitude of 6.0\pm0.4 x 10^-5). We confirm that the method we perfected can be used to retrieve an exoplanet's reflected signal, even with current observing facilities. The advent of next generation of observing facilities will yield new opportunities for this type of technique to probe deeper into exoplanets.Comment: 9 pages, 6 figure

    Kidney Graft Dysfunction in a Patient with SARS-CoV-2 Pneumonia – Not Everything is COVID 19

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    info:eu-repo/semantics/publishedVersio

    Dual-probe decoherence microscopy: Probing pockets of coherence in a decohering environment

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    We study the use of a pair of qubits as a decoherence probe of a non-trivial environment. This dual-probe configuration is modelled by three two-level-systems which are coupled in a chain in which the middle system represents an environmental two-level-system (TLS). This TLS resides within the environment of the qubits and therefore its coupling to perturbing fluctuations (i.e. its decoherence) is assumed much stronger than the decoherence acting on the probe qubits. We study the evolution of such a tripartite system including the appearance of a decoherence-free state (dark state) and non-Markovian behaviour. We find that all parameters of this TLS can be obtained from measurements of one of the probe qubits. Furthermore we show the advantages of two qubits in probing environments and the new dynamics imposed by a TLS which couples to two qubits at once.Comment: 29 pages, 10 figure
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