Hawking Radiation as Tunneling: the D-dimensional rotating case

The tunneling method for the Hawking radiation is revisited and applied to the $D$ dimensional rotating case. Emphasis is given to covariance of results. Certain ambiguities afflicting the procedure are resolved.Comment: Talk delivered at the Seventh International Workshop Quantum Field Theory under the influence of External Conditions, QFEXT'05, september 05,Barcelona, Spain. To appear in Journal of Phys.

Semiclassical Methods for Hawking Radiation from a Vaidya Black Hole

We derive the general form of Hawking temperature for Vaidya black hole in the tunneling pictures. This kind of black hole is regarded as the description of a more realistic one since it's time dependent decreasing mass due to the evaporation process. Clearly, the temperature would be time dependent as our findings. We use the semiclassical methods, namely radial null geodesic and complex paths methods. Both methods are found to give the same results. Then, we discuss the possible form of corresponding entropy.Comment: REVTeX 4, 11 pages, no figures, accepted for publication in IJMPA; v2: eq.5 is correcte

On tunneling across horizons

The tunneling method for stationary black holes in the Hamilton-Jacobi variant is reconsidered in the light of various critiques that have been moved against. It is shown that once the tunneling trajectories have been correctly identified the method isfree from internal inconsistencies, it is manifestly covariant, it allows for the extension to spinning particles and it can even be used without solving the Hamilton-Jacobi equation. These conclusions borrow support on a simple analytic continuation of the classical action of a pointlike particle, made possible by the unique assumption that it should be analytic in complexified Schwarzschild or Kerr-Newman spacetimes. A more general version of the Parikh-Wilczek method will also be proposed along these lines.Comment: Latex Document, 5 pages, 2 figures, title changed, abstract changed, added references, results unchange

Clinical recrudescence of chronic untreated P. malariae infection after BNT162b2 CoVID-19 vaccine

We described a case of clinical reactivation of chronic P. malariae infection following CoVID-19 vaccination with BNT162b2 (Pifzer-Biontech CoVID-19 vaccine) in a 48-year old Italian man.The patient came to our attention for fever of unknown origin show a quartan pattern (every third day) associated to splenomegaly, the onset of the fever occurred one month after CoVID-19 vaccination with BNT162b2. P. malariae was diagnosed using Carestart™ malaria rapid test and Polymerase-Chain Reaction. Post-vaccine transient reduction of immune reactivity is described in literature, although the mechanism is unknown

Cardiovascular Responses Induced by Obstructive Apnea Are Enhanced in Hypertensive Rats Due to Enhanced Chemoreceptor Responsivity

Spontaneously hypertensive rats (SHR), like patients with sleep apnea, have hypertension, increased sympathetic activity, and increased chemoreceptor drive. We investigated the role of carotid chemoreceptors in cardiovascular responses induced by obstructive apnea in awake SHR. A tracheal balloon and vascular cannulas were implanted, and a week later, apneas of 15 s each were induced. the effects of apnea were more pronounced in SHR than in control rats (Wistar Kyoto; WKY). Blood pressure increased by 57 +/- 3 mmHg during apnea in SHR and by 28 +/- 3 mmHg in WKY (p < 0.05, n = 14/13). the respiratory effort increased by 53 +/- 6 mmHg in SHR and by 34 +/- 5 mmHg in WKY. the heart rate fell by 209 +/- 19 bpm in SHR and by 155 +/- 16 bpm in WKY. the carotid chemoreceptors were then inactivated by the ligation of the carotid body artery, and apneas were induced two days later. the inactivation of chemoreceptors reduced the responses to apnea and abolished the difference between SHR and controls. the apnea-induced hypertension was 11 +/- 4 mmHg in SHR and 8 +/- 4 mmHg in WKY. the respiratory effort was 15 +/- 2 mmHg in SHR and 15 +/- 2 mmHg in WKY. the heart rate fell 63 +/- 18 bpm in SHR and 52 +/- 14 bpm in WKY. Similarly, when the chemoreceptors were unloaded by the administration of 100% oxygen, the responses to apnea were reduced. in conclusion, arterial chemoreceptors contribute to the responses induced by apnea in both strains, but they are more important in SHR and account for the exaggerated responses of this strain to apnea.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilFAPESP: 2010/19705-6CNPq: 472187/2010-4Web of Scienc

Profile of Trypanosoma cruzi Infection in a Tropical Medicine Reference Center, Northern Italy

Chagas disease (CD) is endemic in Central and South America, Mexico and even in some areas of the United States. However, cases have been increasingly recorded also in non-endemic countries. The estimated number of infected people in Europe is in a wide range of 14000 to 181000 subjects, mostly resident in Spain, Italy and the United Kingdom

Role of ventricular tachycardia ablation in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive fibro-fatty replacement of the myocardium that represents the substrate for recurrent sustained ventricular tachycardia (VT). These arrhythmias characterize the clinical course of a sizeable proportion of patients and have significant implications for their quality of life and long-term prognosis. Antiarrhythmic drugs are often poorly tolerated and usually provide incomplete control of arrhythmia relapses. Catheter ablation is a potentially effective strategy to treat frequent VT episodes and ICD shocks in ARVC patients. The aims of this review are to discuss the electrophysiological and electroanatomic substrates of ventricular tachycardia in patients with ARVC and to analyze the role of catheter ablation in their management with particular reference to selection of patients, technical issues, potential complications and outcomes

On the semiclassical treatment of Hawking radiation

In the context of the semiclassical treatment of Hawking radiation we prove the universality of the reduced canonical momentum for the system of a massive shell self gravitating in a spherical gravitational field within the Painlev\'e family of gauges. We show that one can construct modes which are regular on the horizon both by considering as hamiltonian the exterior boundary term and by using as hamiltonian the interior boundary term. The late time expansion is given in both approaches and their time Fourier expansion computed to reproduce the self reaction correction to the Hawking spectrum.Comment: 18 pages, LaTeX, Corrected typo

Hawking radiation as tunneling and the unified first law of thermodynamics at the apparent horizon in the FRW universe

Relations between the tunneling rate and the unified first law of thermodynamics at the apparent horizon of the FRW universe are investigated. The tunneling rate arises as a consequence of the unified first law of thermodynamics in such a dynamical system. The analysis shows obviously how the tunneling is intimately connected with the unified first law of thermodynamics through the principle of conservation of energy.Comment: Latex, 9 pages, no figur

Observer Dependent Horizon Temperatures: a Coordinate-Free Formulation of Hawking Radiation as Tunneling

We reformulate the Hamilton-Jacobi tunneling method for calculating Hawking radiation in static, spherically-symmetric spacetimes by explicitly incorporating a preferred family of frames. These frames correspond to a family of observers tied to a locally static timelike Killing vector of the spacetime. This formulation separates the role of the coordinates from the choice of vacuum and thus provides a coordinate-independent formulation of the tunneling method. In addition, it clarifies the nature of certain constants and their relation to these preferred observers in the calculation of horizon temperatures. We first use this formalism to obtain the expected temperature for a static observer at finite radius in the Schwarzschild spacetime. We then apply this formalism to the Schwarzschild-de Sitter spacetime, where there is no static observer with 4-velocity equal to the static timelike Killing vector. It is shown that a preferred static observer, one whose trajectory is geodesic, measures the lowest temperature from each horizon. Furthermore, this observer measures horizon temperatures corresponding to the well-known Bousso-Hawking normalization.Comment: 11 pages, 1 2-part figure, references added, appendix added, discussion streamline