Conformal entropy from horizon states: Solodukhin's method for spherical, toroidal, and hyperbolic black holes in D-dimensional anti-de Sitter spacetimes

A calculation of the entropy of static, electrically charged, black holes with spherical, toroidal, and hyperbolic compact and oriented horizons, in D spacetime dimensions, is performed. These black holes live in an anti-de Sitter spacetime, i.e., a spacetime with negative cosmological constant. To find the entropy, the approach developed by Solodukhin is followed. The method consists in a redefinition of the variables in the metric, by considering the radial coordinate as a scalar field. Then one performs a 2+(D-2) dimensional reduction, where the (D-2) dimensions are in the angular coordinates, obtaining a 2-dimensional effective scalar field theory. This theory is a conformal theory in an infinitesimally small vicinity of the horizon. The corresponding conformal symmetry will then have conserved charges, associated with its infinitesimal conformal generators, which will generate a classical Poisson algebra of the Virasoro type. Shifting the charges and replacing Poisson brackets by commutators, one recovers the usual form of the Virasoro algebra, obtaining thus the level zero conserved charge eigenvalue L_0, and a nonzero central charge c. The entropy is then obtained via the Cardy formula.Comment: 21 page

Developmental Toxicity of Endocrine Disrupters Bisphenol A and Vinclozolin in a Terrestrial Isopod

Studies of the effects of endocrine-disrupting compounds (EDCs) on invertebrates are still largely underrepresented. This work aims to fill this gap by assessing the effects of bisphenol A (BPA) and vinclozolin (Vz) on the terrestrial isopod Porcellio scaber (common rough woodlouse). Male adult and sexually undifferentiated juvenile woodlice were exposed to the toxicants. Effects on molting regime and growth were investigated independently for males and female woodlice after sexual differentiation. Both chemicals elicited developmental toxicity to P. scaber by causing overall decreased growth. Nevertheless, BPA induced molting, whereas Vz delayed it. Although the LC50 values for juvenile and adult survival were fairly similar, juvenile woodlice showed an increased chronic sensitivity to both chemicals, and female woodlice were most the sensitive to BPA. We recommend the use of adults, juveniles, female, and male woodlice, as well as a large range of toxicant concentrations, to provide valuable information regarding differential dose responses, effects, and threshold values for EDCs

Quasi-black holes: definition and general properties

Objects that are on the verge of being extremal black holes but actually are distinct in many ways are called quasi-black holes. Quasi-black holes are defined here and treated in a unified way through the displaying of their properties. The main ones are (i) there are infinite redshift whole regions, (ii) the spacetimes exhibit degenerate, almost singular, features but their curvature invariants remain perfectly regular everywhere, (iii) in the limit under discussion, outer and inner regions become mutually impenetrable and disjoint, although, in contrast to the usual black holes, this separation is of a dynamical nature, rather than purely causal, (iv) for external far away observers the spacetime is virtually indistinguishable from that of extremal black holes. It is shown, in addition, that quasi-black holes must be extremal. Connections with black hole and wormhole physics are also drawn.Comment: 29 pages, minor change

Reply to "Comment on 'Quantization of FRW spacetimes in the presence of a cosmological constant and radiation'"

The Comment by Amore {\it et al.} [gr-qc/0611029] contains a valid criticism of the numerical precision of the results reported in a recent paper of ours [Phys. Rev. D {\bf 73}, 044022 (2006)], as well as fresh ideas on how to characterize a quantum cosmological singularity. However, we argue that, contrary to what is suggested in the Comment, the quantum cosmological models we studied show hardly any sign of singular behavior.Comment: 4 pages, accepted by Physical Review

The Asymptotic Dynamics of two-dimensional (anti-)de Sitter Gravity

We show that the asymptotic dynamics of two-dimensional de Sitter or anti-de Sitter Jackiw-Teitelboim (JT) gravity is described by a generalized two-particle Calogero-Sutherland model. This correspondence is established by formulating the JT model of (A)dS gravity in two dimensions as a topological gauge theory, which reduces to a nonlinear 0+1-dimensional sigma model on the boundary of (A)dS space. The appearance of cyclic coordinates allows then a further reduction to the Calogero-Sutherland quantum mechanical model.Comment: 16 pages, LaTeX, no figures, uses JHEP.cls. v2: Some references and comments added. v3: Minor errors correcte

Thermodynamics of the two-dimensional black hole in the Teitelboim-Jackiw theory

The two-dimensional theory of Teitelboim and Jackiw has constant and negative curvature. In spite of this, the theory admits a black hole solution with no singularities. In this work we study the thermodynamics of this black hole using York's formalism.Comment: 16 pages, Late

Higher-Derivative Two-Dimensional Massive Fermion Theories

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a higher-derivative theory of order 2N+1 consist of a physical usual massive fermion, quantized with positive metric, plus 2N unphysical massless fermions, quantized with opposite metrics. The positive metric Hilbert subspace, which is isomorphic to the space of states of a massive free fermion theory, is selected by a subsidiary-like condition. Employing the standard bosonization scheme, the equivalent boson theory is derived. The results obtained are used as a guideline to discuss the solution of a theory including a current-current interaction.Comment: 23 pages, Late

On the stability of general relativistic geometric thin disks

The stability of general relativistic thin disks is investigated under a general first order perturbation of the energy momentum tensor. In particular, we consider temporal, radial and azimuthal "test matter" perturbations of the quantities involved on the plane $z=0$. We study the thin disks generated by applying the "displace, cut and reflect" method, usually known as the image method, to the Schwarzschild metric in isotropic coordinates and to the Chazy-Curzon metric and the Zipoy-Voorhees metric ($\gamma$-metric) in Weyl coordinates. In the case of the isotropic Schwarzschild thin disk, where a radial pressure is present to support the gravitational attraction, the disk is stable and the perturbation favors the formation of rings. Also, we found the expected result that the thin disk models generated by the Chazy-Curzon and Zipoy-Voorhees metric with only azimuthal pressure are not stable under a general first order perturbationComment: 11 pages, RevTex. Phys Rev D (in press

Care causing diagnosis, comorbidities and nutritional status of patients in continuous long term care unit

Introduction: Poor nutritional status has negative implications on prognosis, cost of care, morbidity and mortality. However, when nutritional assessment is not implemented, malnutrition can go untreated. Objectives: The aim of this study was to establish a relationship between care causing diagnosis, existing comorbidities and nutritional status of patients admitted to a long-term care unit. Methods: In the context of Nutrition Day audit, from 2016 to 2018, nutritional status was assessed using Mini Nutritional Assessment. Sociodemographic and anthropometric data, as well as medical history were collected. Results: Sixty-two individuals were included (51.6% male), with a mean age of 7711 years. Mean BMI was 22.94.3kg/m2. Most of the patients were bedridden or in wheelchair (51.6%). A great part of the sample was at risk of malnutrition (40.3%) and 27.4% was malnourished. The majority of the sample showed dementia (75.8%) and 66.2% had depression. A correlation was found between nutritional status and cognitive status(r = 0.445; p = 0.000); and between nutritional status and functional capacity(r = 0.284; p = 0.025). Care causing diagnosis for most of the patients was central nervous system disease (66.1%), followed by heart disease (59.7%), skeletal muscle disease (30.6%) and cancer (17.7%). An association was found between heart disease and malnutrition (p = 0.023). Almost all of the sample was polymedicated (91.9%) and most was taking antypsychotics and/or neuroleptics (71.0%). Conclusions: In this long-term care unit, malnutrition presented a significant prevalence. Cognitive status decline and low functional capacity seem to be correlated with a worse nutritional status. Also, heart disease was associated with malnutrition, meaning that these are significant risk factors for the development of malnutrition. Nutrition Day audit brings awareness to the importance of nutritional care, as well as the need for development of nutritional screening and assessment protocols.info:eu-repo/semantics/publishedVersio

Nutrition Day in nursing homes – risk factors for malnutrition

Introduction: Malnutrition in institutionalized older adults has a significant prevalence, and is associated with cognitive decline, higher morbidity and mortality rates. Objectives: The aim of this study was to assess risk factors for malnutrition in nursing home residents. Methods: Through Nutrition Day audit (2016–2018), demographic and anthropometric data was collected, as well as medical history and nutritional status according to Mini Nutritional Assessment. Results: Sixty-three individuals were included (57.1% male), with a mean age of 849 years. Mean Body Mass Index was 21.55.1 kg/m2. Malnutrition was identified in 47.6% of the patients and nutritional risk in 28.6%. Most of the sample (61.9%) was bedridden or in wheelchair. Most of the individuals showed dementia (82.5%) and depression (79.3%). A positive moderate significant correlation was found between nutritional status and cognitive status (r = 0.407;p=0.001); and between nutritional status and functional capacity (r = 0.474;p=0.000). Considering the diagnosis which caused institutionalization, brain pathologies were the most prevalent (79.4%), followed by cardiovascular diseases (49.2%) and skeletal muscle diseases (27.0%). Mean number of medications taken daily was 74 and 74.6% of the residents were polymedicated. The majority (61.9%) was taking antipsychotics and/or neuroleptics and 28.6% were taking antidepressives. Conclusions: In this sample, individuals are essentially older adults with a high prevalence of malnutrition. The high level of dependence and the presence of dementia are significant risk factors for the development of this condition. Disturbed emotional status and the use of multiple drugs associated with impaired appetite, although without statistically significant associations with nutritional status, are highly prevalent in this sample. Nutritional screening in this population is essential and timely necessary, aiming to prevent deterioration or improve nutritional status.info:eu-repo/semantics/publishedVersio