A new spin-2 self-dual model in D=2+1D=2+1

There are three self-dual models of massive particles of helicity +2 (or -2) in $D=2+1$. Each model is of first, second, and third-order in derivatives. Here we derive a new self-dual model of fourth-order, \cL {SD}^{(4)}, which follows from the third-order model (linearized topologically massive gravity) via Noether embedment of the linearized Weyl symmetry. In fact, each self-dual model can be obtained from the previous one \cL {SD}^{(i)} \to \cL {SD}^{(i+1)}, i=1,2,3 by the Noether embedment of an appropriate gauge symmetry, culminating in \cL {SD}^{(4)}. The new model may be identified with the linearized version of \cL {HDTMG} = \epsilon^{\mu\nu\rho} \Gamma_{\mu\gamma}^\epsilon (\p_\nu\Gamma_{\epsilon\rho}^\gamma + (2/3)\Gamma_{\nu\delta}^\gamma \Gamma_{\rho\epsilon}^\delta) /8 m + \sqrt{-g}(R_{\mu\nu} R^{\nu\mu} - 3 R^2/8) /2 m^2 . We also construct a master action relating the third-order self-dual model to \cL {SD}^{(4)} by means of a mixing term with no particle content which assures spectrum equivalence of \cL {SD}^{(4)} to other lower-order self-dual models despite its pure higher derivative nature and the absence of the Einstein-Hilbert action. The relevant degrees of freedom of \cL {SD}^{(4)} are encoded in a rank-two tensor which is symmetric, traceless and transverse due to trivial (non-dynamic) identities, contrary to other spin-2 self-dual models. We also show that the Noether embedment of the Fierz-Pauli theory leads to the new massive gravity of Bergshoeff, Hohm and Townsend.Comment: 14 pages, no figures, typos fixed, reference (19) modifie

Osteomielite e Sacro-ileíte Abecedada a Aggregatibacter Aphrophilus

Introdução: O Aggregatibacter aphrophilus é um cocobacilo Gram negativo do grupo HACEK presente na flora comensal da orofaringe. Foi descrito como agente etiológico de infecções osteo-articulares em adultos. Não existem casos publicados em idade pediátrica. Caso Clínico: Adolescente de 14 anos do sexo masculino, em programa de reabilitação dentária, apresentou-se com febre e lombalgia direita com 2 dias de evolução. Evidenciava dor intensa à mobilização do membro inferior ipsilateral. Analiticamente salientava-se: 5,70x109/L leucócitos, neutrofilia 92,5%, PCR 138,4mg/L, VS 11mm/h. A RMN era sugestiva de sacro-ileíte. Foi medicado empiricamente com Flucloxacilina e Gentamicina ev, a que se adicionou Clindamicina 48h depois, por agravamento clínico e analítico. Repetiu RMN em D8 que revelou osteomielite subcondral no ilíaco direito e abcesso na sacro-ilíaca. Fez-se desbridamento cirúrgico, com isolamento de A. aphrophilus do abcesso. Cumpriu 6 semanas de antibioterapia dirigida (21 dias de ceftriaxone ev e, posteriormente, levofloxacina oral) com resolução clínico-imagiológica completa. De referir: hemoculturas seriadas negativas, ausência de critérios de endocardite e exclusão de doença granulomatosa crónica. Conclusões: Neste caso de infecção osteo-articular sem resposta à terapêutica empírica, com hemoculturas seriadas negativas, a colheita de material biológico adequado para identificação do A. aphrophilus foi crucial para instituição de terapêutica eficaz. Este caso alerta para a possibilidade de doença invasiva por microrganismos de baixa patogenicidade em imunocompetentes, na presença de factores facilitadores de disseminação hematogénea como a manipulação dentária recente.info:eu-repo/semantics/publishedVersio

Induced Lorentz- and CPT-violating Chern-Simons term in QED: Fock-Schwinger proper time method

Using the Fock-Schwinger proper time method, we calculate the induced Chern-Simons term arising from the Lorentz- and CPT-violating sector of quantum electrodynamics with a $b_\mu \bar{\psi}\gamma^\mu \gamma_5 \psi$ term. Our result to all orders in $b$ coincides with a recent linear-in-$b$ calculation by Chaichian et al. [hep-th/0010129 v2]. The coincidence was pointed out by Chung [Phys. Lett. {\bf B461} (1999) 138] and P\'{e}rez-Victoria [Phys. Rev. Lett. {\bf 83} (1999) 2518] in the standard Feynman diagram calculation with the nonperturbative-in-$b$ propagator.Comment: 11 pages, no figur

Coexistence of Pheochromocytoma and Renal Artery Stenosis in a Pediatric Patient with Hypertension

Pheochromocytoma and renal artery stenosis are surgically treatable causes of hypertension. Although rare, the coexistence of pheochromocytoma and renal artery stenosis has been described in case reports. Common pathophysiological mechanisms other than extrinsic compression may be involved in this association, such as catecholamine-induced vasospasm. The early recognition of the association of pheochromocytoma with renal artery stenosis is essential for appropriate treatment planning. We present the case of a previously healthy tenyear- old boy who presented with hypertensive encephalopathy, tachycardia and diaphoresis. Hypertension was found to be secondary to a catecholamine-producing tumor associated with coexisting renal artery stenosis. Hypertension resolved a few months after successful pheochromocytoma excision, without renal artery revascularization.info:eu-repo/semantics/publishedVersio

Lower Free Triiodothyronine Levels Within the Reference Range Are Associated with Higher Cardiovascular Mortality: an Analysis of the NHANES

Thyroid hormones play a central role in cardiovascular homeostasis. Lower free triiodothyronine (FT3) levels have been associated with worse prognosis in several conditions. However, contrary to thyrotropin (TSH) and free thyroxine (FT4), the role of FT3 in morbidity and mortality in the general population remains uncertain. Our objective was to evaluate the association between within the normal range FT3 levels and mortality in the general population.info:eu-repo/semantics/publishedVersio

Stationary solutions for the parity-even sector of the CPT-even and Lorentz-covariance-violating term of the standard model extension

In this work, we focus on some properties of the parity-even sector of the CPT-even electrodynamics of the standard model extension. We analyze how the six non-birefringent terms belonging to this sector modify the static and stationary classical solutions of the usual Maxwell theory. We observe that the parity-even terms do not couple the electric and magnetic sectors (at least in the stationary regime). The Green's method is used to obtain solutions for the field strengths E and B at first order in the Lorentz- covariance-violating parameters. Explicit solutions are attained for point-like and spatially extended sources, for which a dipolar expansion is achieved. Finally, it is presented an Earth-based experiment that can lead (in principle) to an upper bound on the anisotropic coefficients as stringent as $(\widetilde{\kappa}_{e-}) ^{ij}<2.9\times10^{-20}.$Comment: 8 pages, revtex style, revised published version, to appear in EPJC (2009

Consistency analysis of a nonbirefringent Lorentz-violating planar model

In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor $\kappa_{\mu\nu}$. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for $0\leq\kappa_{00}<1$. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a $\lambda|\varphi|^{4}-$Higgs field supports compactlike vortex configurations.Comment: 11 pages, revtex style, final revised versio

On the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects on the Harmonic Oscillator

In this work, we obtain bound states for a nonrelativistic spin-half neutral particle under the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects. We present a new possible scenario of studying the Lorentz symmetry breaking effects on a nonrelativistic quantum system defined by a fixed space-like vector field parallel to the radial direction interacting with a uniform magnetic field along the z-axis. Furthermore, we also discuss the influence of a Coulomb-like potential induced by Lorentz symmetry violation effects on the two-dimensional harmonic oscillator.Comment: 14 pages, no figure, this work has been accepted for publication in The European Physical Journal Plu

Seasonal Changes in Colour: A Comparison of Structural, Melanin- and Carotenoid-Based Plumage Colours

Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult, although whether this affects signalling has not been sufficiently assessed.) displaying various coloration types (melanin-, carotenoid-based and structural). Birds were caught regularly during three years to measure plumage reflectance. We used models of avian colour vision to derive two variables, one describing chromatic and the other achromatic variation over the year that can be compared in magnitude among different colour types. All studied plumage patches but one (yellow breast of the blue tit) showed significant chromatic changes over the year, although these were smaller than for a typical dynamic trait (bill colour). Overall, structural colours showed a reduction in relative reflectance at shorter wavelengths, carotenoid-based colours the opposite pattern, while no general pattern was found for melanin-based colours. Achromatic changes were also common, but there were no consistent patterns of change for the different types of colours.Changes of plumage coloration independent of moult are probably widespread; they should be perceivable by birds and have the potential to affect colour signalling