Entanglement from thermal black body radiation
Braun, Daniel
2005-01-01
Two non--interacting quantum systems which couple to a common environment with many degrees of freedom initially in thermal equilibrium can become entangled due to the indirect interaction mediated through this heat bath. I examine here the dynamics of reservoir induced entanglement for a heat bath consisting of a thermal electro--magnetic radiation field, such as black body radiation or the cosmic microwave background, and show how the effect can be understood as result of an effective induc...
Fermi golden rule for $N$-body systems in a black-body radiation
Ostilli, Massimo
2016-01-01
We review the calculation of the Fermi golden rule for a system of $N$-body dipoles, magnetic or electric, weakly interacting with a black-body radiation. By using the magnetic or electric field-field correlation function evaluated in the 1960s for the black body radiation, we deduce a general formula for the transition rates and study its limiting, fully coherent or fully incoherent, regimes.
Nonlocal Effects in Black Body Radiation
Bremm, G N
2016-01-01
Nonlocal electrodynamics is a formalism developed to include nonlocal effects in the measurement process caused by the non-inertial state of the observers. This theory modifies Maxwell's electrodynamics by eliminating the hypothesis of locality that assumes an accelerated observer simultaneously equivalent to a comoving inertial frame of reference. In this scenario, the transformation between an inertial and accelerated observer is generalized which affects the properties of physical fields. In particular, we analyze how an uniformly accelerated observer perceives a homogeneous and isotropic blackbody radiation. We show that all nonlocal effects are transient and most relevant in the first period of acceleration.
Minimal length, maximal momentum and thermodynamics of black body radiation
Shababi, Homa
2013-01-01
In this paper we study thermodynamics of black body radiation in the presence of quantum gravitational effects through a Generalized Uncertainty Principle that admits both a minimal measurable length and a maximal momentum. We focus on quantum gravity induced modifications of thermodynamical quantities in this framework. Some important issues such as the generalized Planck distribution, Wien s law and Dulong Petit law are studied in this setup with details.
Overcoming black body radiation limit in free space: metamaterial superemitter
Maslovski, Stanislav I.; Simovski, Constantin R.; Tretyakov, Sergei A.
2016-01-01
Here, we demonstrate that the power spectral density of thermal radiation at a specific wavelength produced by a body of finite dimensions set up in free space under a fixed temperature could be made theoretically arbitrary high, if one could realize double negative metamaterials with arbitrary small loss and arbitrary high absolute values of permittivity and permeability (at a given frequency). This result refutes the widespread belief that Planck’s law itself sets a hard upper limit on the spectral density of power emitted by a finite macroscopic body whose size is much greater than the wavelength. Here we propose a physical realization of a metamaterial emitter whose spectral emissivity can be greater than that of the ideal black body under the same conditions. Due to the reciprocity between the heat emission and absorption processes such cooled down superemitter also acts as an optimal sink for the thermal radiation—the ‘thermal black hole’—which outperforms Kirchhoff-Planck’s black body which can absorb only the rays directly incident on its surface. The results may open a possibility to realize narrowband super-Planckian thermal radiators and absorbers for future thermo-photovoltaic systems and other devices.
Thermalization of magnetized electrons from black body radiation
International Nuclear Information System (INIS)
We describe an interesting mechanism whereby an electron in a strong magnetic field can have both the parallel and perpendicular motions come into thermal equilibrium with black body radiation. The mechanism does not include any collisions with other particles and can overcome the extreme slowing of thermalization of highly magnetized particles at low temperatures. The mechanism depends upon the magnetic field strength having a spatial variation. We provide results from two example cases. This mechanism could affect the temperatures that can be achieved in experiments devoted to trapping antihydrogen
Energy shift due to anisotropic black body radiation
Flambaum, Victor V; Safronova, Marianna S
2015-01-01
In many applications a source of the black-body radiation (BBR) can be highly anisotropic. This leads to the BBR shift that depends on tensor polarizability and on the projection of the total angular momentum of ions and atoms in a trap. We derived formula for the anisotropic BBR shift and performed numerical calculations of this effect for Ca$^+$ and Yb$^+$ transitions of experimental interest. These ions used for a design of high-precision atomic clocks, fundamental physics tests such as search for the Lorentz invariance violation and space-time variation of the fundamental constants, and quantum information. Anisotropic BBR shift may be one of the major systematic effect in these experiments.
On the thermodynamics of the conversion of partially polarized black-body radiation
Badescu, V.
1992-01-01
This paper considers a model consisting of : (i) a source of partially polarized black-body radiation (the pump), (ii) a thermally radiative or non-radiative ambient sink and (iii) two energy converters. The first converter (RH) transforms the energy of the black-body radiation into heat, while the second one (HW) (which has a non-zero entropy generation rate) uses that heat to produce work. The entropy-generation rates in the two converters are non-negative only when some conditions are sati...
Calogeracos, A
2002-01-01
We address the question of radiation emission from a perfect mirror that starts from rest and follows the trajectory z=-ln(cosht) ad infinitum. We show that a correct derivation of the black body spectrum via the calculation of Bogolubov amplitudes requires consideration of the whole trajectory and not just of its asymptotic part.
International Nuclear Information System (INIS)
We address the question of radiation emission from a perfect mirror that starts from rest and follows the trajectory z=-ln(cosh t) until t→∞. We show that a correct derivation of the black body spectrum via the calculation of the Bogolubov amplitudes requires consideration of the whole trajectory and not just of its asymptotic part. (author)
The effects of solar radiation and black body re-radiation on thermal comfort.
Hodder, Simon; Parsons, Ken
2008-04-01
When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces.
A VARIATIONAL EXPECTATION-MAXIMIZATION METHOD FOR THE INVERSE BLACK BODY RADIATION PROBLEM
Institute of Scientific and Technical Information of China (English)
Jiantao Cheng; Tie Zhou
2008-01-01
The inverse black body radiation problem, which is to reconstruct the area tempera-ture distribution from the measurement of power spectrum distribution, is a well-known ill-posed problem. In this paper, a variational expectation-maximization (EM) method is developed and its convergence is studied. Numerical experiments demonstrate that the variational EM method is more efficient and accurate than the traditional methods, in-cluding the Tikhonov regularization method, the Landweber method and the conjugate gradient method.
International Nuclear Information System (INIS)
We report on electron cooling power measurements in few-layer graphene excited by Joule heating by means of a new setup combining electrical and optical probes of the electron and phonon baths temperatures. At low bias, noise thermometry allows us to retrieve the well known acoustic phonon cooling regimes below and above the Bloch-Grüneisen temperature, with additional control over the phonon bath temperature. At high electrical bias, we show the relevance of direct optical investigation of the electronic temperature by means of black-body radiation measurements. In this regime, the onset of new efficient relaxation pathways involving optical modes is observed. (paper)
Indian Academy of Sciences (India)
B K Sahoo
2014-08-01
We present here an overview of the role of the multipolar black-body radiation (BBR) shifts in the single ion atomic clocks to appraise the anticipated 10-18 uncertainty level. With an attempt to use the advanced technologies for reducing the instrumental uncertainties at the unprecedented low, it is essential to investigate contributions from the higher-order systematics to achieve the ambitious goal of securing the most precise clock frequency standard. In this context, we have analysed contributions to the BBR shifts from the multipolar polarizabilities in a few ion clocks.
Black-body radiation shift of atomic energy-levels:The $ (Z \\alpha)^2\\alpha T^2/m $ correction
Zhou, Wanping; Mei, Xuesong; Lu, Jingjun; Qiao, Haoxue
2016-01-01
The next-to-leading order black-body radiation(BBR) shift to atomic energy-levels, namely $ (Z\\alpha)^2\\alpha T^2/m $ correction, was studied by using the nonrelativistic quantum electrodynamics(NRQED). We also estimate the one-loop contribution of quadrupole and the two-loop contributions of BBR-shift of the thermal(real) photon. These corrections have not been investigated before. The order of magnitude BBR-shift indicates the one-loop contribution of quadrupole is stronger than the previou...
Destroying black holes with test bodies
Energy Technology Data Exchange (ETDEWEB)
Jacobson, Ted [Center for Fundamental Physics, University of Maryland, College Park, MD 20742-4111 (United States); Sotiriou, Thomas P, E-mail: jacobson@umd.ed, E-mail: T.Sotiriou@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2010-04-01
If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.
Black-body radiation shift of atomic energy-levels:The $ (Z \\alpha)^2\\alpha T^2/m $ correction
Zhou, Wanping; Lu, Jingjun; Qiao, Haoxue
2016-01-01
The next-to-leading order black-body radiation(BBR) shift to atomic energy-levels, namely $ (Z\\alpha)^2\\alpha T^2/m $ correction, was studied by using the nonrelativistic quantum electrodynamics(NRQED) at first. This $T^{2}$-dependent correction has not been investigated before, and only contains the contribution of eletric-dipole of thermal photon. In order to study the contribution of multipolar. We estimate the two-loop contributions of BBR-shift by using quantum electrodynamics approach(QED), and find both one-loop and two-loop diagram contribute to the $ (Z\\alpha)^2\\alpha T^2/m $ correction. Integrating the results which are obtained by these two approaches, the $ (Z\\alpha)^2\\alpha T^2/m $ correction we derived is in principle applicable to multi-electron atoms and contains the contribution of multipolar. The order of magnitude BBR-shift indicates this next-to-leading order BBR-shift may be as significant as the leading order in the multi-electron atoms or cold ones.
Directory of Open Access Journals (Sweden)
Julian Gonzalez-Ayala
2015-06-01
Full Text Available In this work, we present the generalization of some thermodynamic properties of the black body radiation (BBR towards an n-dimensional Euclidean space. For this case, the Planck function and the Stefan–Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then, not much more has been done on this subject, and we believe there are some relevant aspects yet to explore. In addition to the results previously found, we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arises: maxima and minima appear for the n—dimensional BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally, we propose that an optimality criterion in a thermodynamic framework could be related to the 3—dimensional nature of the universe.
Gonzalez-Ayala, Julian; Cordero, Rubén; Angulo-Brown, F
2015-01-01
In this work we present the generalization of some thermodynamic properties of the black body radiation (BBR) towards an $n-$dimensional Euclidean space. For this case the Planck function and the Stefan-Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then no much more has been done on this subject and we believe there are some relevant aspects yet to explore. In addition to the results previously found we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arise, maxima and minima appear for the $n-d$ BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally we propose that an optimality criterion in a thermodynamic framework could have to do with the $3-d$ nature of the universe.
Black Hole Entropy from Entropy of Hawking Radiation
Aghapour, Sajad
2016-01-01
We provide a simple way for calculating the entropy of a Schwarzschild black hole from the entropy of its Hawking radiation. To this end, we show that if a thermodynamic system loses its energy only through the black body radiation, its loss of entropy is always 3/4 of the entropy of the emitted radiation. This proposition enables us to relate the entropy of an evaporating black hole to the entropy of its Hawking radiation. Explicitly, by calculating the entropy of the Hawking radiation emitted in the full period of evaporation of the black hole, we find the Bekenstein-Hawking entropy of the initial black hole.
Schiller, Stephan; Bekbaev, Ashat K; Korobov, Vladimir I
2014-01-01
We calculate the DC Stark effect for three molecular hydrogen ions in the non-relativistic approximation. The effect is calculated both in dependence on the rovibrational state and in dependence on the hyperfine state. We discuss special cases and approximations. We also calculate the AC polarisabilities for several rovibrational levels, and therefrom evaluate accurately the black-body radiation shift, including the effects of excited electronic states. The results enable the detailed evaluation of certain systematic shifts of the transitions frequencies for the purpose of ultra-high-precision optical, microwave or radio-frequency spectroscopy in ion traps.
Zaleski, Daniel P.; Horrocks, Benjamin R.; Walker, Nick
2015-06-01
A new experiment appropriate for both general chemistry and physical chemistry students will be described. The experiment utilizes "pocket size" USB spectrometers (operating in the UV/vis region) coupled with fiber optic cables to record a solar spectrum. A further extension of the experiment involves recording spectra of a light bulb at several voltages (and thus resistances). Using provided software, students can fit black body distributions to their obtained spectra. The software will display the acquired spectrum, a simulation based on their guess temperature, a simulation based on their fit, and OMC2 for both. Students can then compare their results to the known temperature of the sun and the known temperature vs resistance curve of tungsten.
Massive particle radiation from Gibbons-Maeda black hole
Institute of Scientific and Technical Information of China (English)
Fang Heng-Zhong
2010-01-01
This paper investigated the massive particle radiation from Gibbous-Maeda black hole by using a semi-classical method. The calculations showed that, if the self-gravitation of the radiated particle is taken into account, the radiation spectrum deviates from exact black body spectrum and the rate of tunneling equals precisely the exponent of the difference of the black hole entropies before and after emission. The conclusion supports the viewpoint of information conservation.
Stereotactic body radiation therapy
Energy Technology Data Exchange (ETDEWEB)
Lo, Simon S. [Univ. Hospitals Seidman Cancer Center, Cleveland, OH (United States). Dept. of Radiation Oncology; Case Western Reserve Univ., Cleveland, OH (United States). Case Comprehensive Cancer Center; Teh, Bin S. [The Methodist Hospital Cancer Center and Research Institute, Houston, TX (United States). Weill Cornell Medical College; Lu, Jiade J. [National Univ. of Singapore (Singapore). Dept. of Radiation Oncology; Schefter, Tracey E. (eds.) [Colorado Univ., Aurora, CO (United States). Dept. of Radiation Oncology
2012-11-01
Comprehensive an up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. Examines in detail retrospective studies and prospective clinical trials for various organ sites from around the world. Written by world-renowned experts in SBRT from North America, Asia and Europe. Stereotactic body radiation therapy (SBRT) has emerged as an innovative treatment for various primary and metastatic cancers, and the past five years have witnessed a quantum leap in its use. This book provides a comprehensive and up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. It will serve as a detailed resource for this rapidly developing treatment modality. The organ sites covered include lung, liver, spine, pancreas, prostate, adrenal, head and neck, and female reproductive tract. Retrospective studies and prospective clinical trials on SBRT for various organ sites from around the world are examined, and toxicities and normal tissue constraints are discussed. This book features unique insights from world-renowned experts in SBRT from North America, Asia, and Europe. It will be necessary reading for radiation oncologists, radiation oncology residents and fellows, medical physicists, medical physics residents, medical oncologists, surgical oncologists, and cancer scientists.
Hawking Radiation from Regular Black Hole as a Possible Probe for Black Hole Interior Structure
Deng, Yanbin
2016-01-01
The notion of the black hole singularity and the proof of the singularity theorem in general relativity were considered great successes in gravitational physics. On the other hand they also presented deep puzzles to physicists. Conceptual challenges were set up by the intractability of the singularity. The existence of black hole horizons which cover up the interior, including the singularity of the black hole from outside observers, builds an information curtain, further hindering physicists from understanding the nature of the singularity and the interior structure of black holes. The regular black hole is a concept produced out of multiple attempts to establish a tractable and understandable interior structure for black hole and to avoid the singularity inside the black hole body. A method is needed to check the correctness of the new constructions of black holes. After studying the Hawking radiation by fermion tunnelling from one type of regular black hole, structure dependent results were obtained. The r...
The relativistic one-loop and two-loop black-body radiation shift of atomic energy-levels
Zhou, Wanping; Mei, Xuesong; Qiao, Haoxue
2016-01-01
The thermal relativistic one-loop and two-loop self-energy corrections of atomic energy-levels induced by the blackbody radiation(BBR) are studied. We estimated the magnitude of BBR-shift of this results in the hydrogen-like atom. The order of magnitude indicated the two loop correction of the real photon is feeble, but that thermal relativistic one-loop self-energy correction and the thermal two-loop self-energy corrections induced by real and virtual photon are abnormal high, which may exce...
The relativistic one-loop and two-loop black-body radiation shift of atomic energy-levels
Zhou, Wanping; Qiao, Haoxue
2016-01-01
The thermal relativistic one-loop and two-loop self-energy corrections of atomic energy-levels induced by the blackbody radiation(BBR) are studied. We estimated the magnitude of BBR-shift of this results in the hydrogen-like atom. The order of magnitude indicated the two loop correction of the real photon is feeble, but that thermal relativistic one-loop self-energy correction and the thermal two-loop self-energy corrections induced by real and virtual photon are abnormal high, which may exceed the leading order correction of BBR in the hydrogen with high $Z$ or low $T$.
Dark Spinors Hawking Radiation in String Theory Black Holes
Directory of Open Access Journals (Sweden)
R. T. Cavalcanti
2016-01-01
Full Text Available The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
Scalar field radiation from dilatonic black holes
Gohar, H.; Saifullah, K.
2012-12-01
We study radiation of scalar particles from charged dilaton black holes. The Hamilton-Jacobi method has been used to work out the tunneling probability of outgoing particles from the event horizon of dilaton black holes. For this purpose we use WKB approximation to solve the charged Klein-Gordon equation. The procedure gives Hawking temperature for these black holes as well.
Black Hole Radiation and Volume Statistical Entropy
Rabinowitz, M
2005-01-01
The simplest possible equations for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh are can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius RH
The thermal radiation from dynamic black holes
Institute of Scientific and Technical Information of China (English)
2008-01-01
Using the related formula of dynamic black holes, the instantaneous radiation energy density of the general spherically symmetric charged dynamic black hole and the arbitrarily accelerating charged dynamic black hole is calculated. It is found that the instantaneous radiation energy density of black hole is always proportional to the quartic of the temperature of event horizon in the same direction. The proportional coefficient of generalized Stefan-Boltzmann is no longer a constant, and it becomes a dynamic coefficient that is related to the event horizon changing rate, space-time structure near event horizon and the radiation absorption coefficient of the black hole. It is shown that there should be an internal relation between the gravitational field around black hole and its thermal radiation.
Radiation background of Black Sea coastal environment
International Nuclear Information System (INIS)
The main objective of the project is to establish the level of radiation background and its sources in the Black Sea coastal environment. Marine samples will be collected in the Black Sea Coast area. The content of different radionuclides will be analyzed and the results will be used in a GIS application. The gamma emitting radionuclides will be measured in ultralow radiation background in the Romanian underground laboratory in salt mine in Slanic-Prahova. The main expected results is an up to date quantification of the radiation sources of the background of the Black Sea coastal environment. (authors)
Quantum Radiation of General Nonstationary Black Holes
Hua, Jia-Chen; Huang, Yong-chang
2006-01-01
This paper has been withdrawn by the authors. Quantum radiative characteristics of 4D semi-classical nonstationary black holes in the general case are investigated by using the method of generalized tortoise coordinate transformation. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we discover that there is a certain relationship that is ignored before between thermal radiation and...
Is Radiation of Quantized Black Holes Observable?
Khriplovich, I. B.; Produit, N.
2006-01-01
If primordial black holes (PBH) saturate the present upper limit on the dark matter density in our Solar system and if their radiation spectrum is discrete, the sensitivity of modern detectors is close to that necessary for detecting this radiation. This conclusion is not in conflict with the upper limits on the PBH evaporation rate.
Reflection, radiation and interference for black holes
Kuchiev, M Yu
2003-01-01
Black holes are capable of reflection: there is a finite probability for any particle that approaches the event horizon to bounce back. The albedo of the black hole depends on its temperature and the energy of the incoming particle. The reflection shares its physical origins with the Hawking process of radiation, both of them arise as consequences of the mixing of the incoming and outgoing waves that takes place on the event horizon.
Black holes radiate mainly on the brane.
Emparan, R; Horowitz, G T; Myers, R C
2000-07-17
We examine the evaporation of a small black hole on a brane in a world with large extra dimensions. Since the masses of many Kaluza-Klein modes are much smaller than the Hawking temperature of the black hole, it has been claimed that most of the energy is radiated into these modes. We show that this is incorrect. Most of the energy goes into the modes on the brane. This raises the possibility of observing Hawking radiation in future high energy colliders if there are large extra dimensions. PMID:10991325
Gravitational radiation from dynamical black holes
Hayward, Sean A.
2005-01-01
An effective energy tensor for gravitational radiation is identified for uniformly expanding flows of the Hawking mass-energy. It appears in an energy conservation law expressing the change in mass due to the energy densities of matter and gravitational radiation, with respect to a Killing-like vector encoding a preferred flow of time outside a black hole. In a spin-coefficient formulation, the components of the effective energy tensor can be understood as the energy densities of ingoing and ...
Quantum black hole and Hawking radiation at microscopic magnifying
Kiselev, V. V.
2005-01-01
We establish a state of stopping the Hawking radiation by quantum Schwarzschild black hole in the framework of quasi-classical thermal quantization for particles behind the horizon. The mechanism of absorption and radiation by the black hole is presented.
Canonical Ensemble Model for Black Hole Radiation
Indian Academy of Sciences (India)
Jingyi Zhang
2014-09-01
In this paper, a canonical ensemble model for the black hole quantum tunnelling radiation is introduced. In this model the probability distribution function corresponding to the emission shell is calculated to second order. The formula of pressure and internal energy of the thermal system is modified, and the fundamental equation of thermodynamics is also discussed.
Anomaly and Hawking radiation from regular black holes
Kim, Wontae; Shin, Hyeonjoon; Yoon, Myungseok
2008-01-01
We consider the Hawking radiation from two regular black holes, the minimal model and the noncommutative black hole. The flux of Hawking radiation is derived by applying the anomaly cancellation method proposed by Robinson and Wilczek. Two regular black holes have the same radiation pattern except for the detailed expression for the Hawking temperature. The resulting flux of the energy-momentum tensor is shown to be precisely the same with the thermal flux from each regular black hole at the ...
Black hole formation by incoming electromagnetic radiation
International Nuclear Information System (INIS)
I revisit a known solution of the Einstein field equations to show that it describes the formation of non-spherical black holes by the collapse of pure electromagnetic monochromatic radiation. Both positive and negative masses are feasible without ever violating the dominant energy condition. The solution can also be used to model the destruction of naked singularities and the evaporation of white holes by emission or reception of light. (note)
Kyasov, A. A.; Dedkov, G. V.
2015-01-01
We have developed a self-consistent description of the radiation heat transfer and dynamics of large perfectly black spherical bodies with sizes much greater than the characteristic wavelength of radiation moving in a photon gas with relativistic velocity. The results can be important in astrophysics.
Cutoffs, Stretched Horizons and Black Hole Radiators
Kaloper, Nemanja
2012-01-01
We argue that if the UV cutoff of the IR theory is of the order, or below, the scale of the stretched horizon in a black hole background, which in turn is significantly lower than the Planck scale, the black hole radiance is controlled by the UV completion of the field theory. In particular, if the UV completion of the theory involves degrees of freedom which cannot be efficiently emitted by the black hole, the naive radiance rate estimated by the counting of the IR degrees of freedom may be dramatically reduced. If we apply this argument to the RS2 brane world, it implies that the emission rates of the low energy CFT modes will be dramatically suppressed: its UV completion is given by the bulk gravity on $AdS_5 \\times S^5$, and the only bulk modes that could be emitted by a black hole are the s-waves of bulk modes with small 4D masses. But their emission is suppressed by bulk warping. This lowers the radiation rate much below the IR estimate, by at least a factor of $N \\simeq M_{Pl}^2 L^2$, and follows direc...
Reexamining Black-Body Shifts for Hydrogenlike Ions
Jentschura, U. D.; Haas, M.
2008-01-01
We investigate black-body induced energy shifts for low-lying levels of atomic systems, with a special emphasis on transitions used in current and planned high-precision experiments on atomic hydrogen and ionized helium. Fine-structure and Lamb-shift induced black-body shifts are found to increase with the square of the nuclear charge number, whereas black-body shifts due to virtual transitions decrease with increasing nuclear charge as the fourth power of the nuclear charge. We also investig...
Non-thermal Hawking radiation from the Kerr black hole
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen; HAO Jia-Bo
2009-01-01
We present a short and direct derivation of Hawking radiation by using the Damour-Ruffini method, as taking into account the self-gravitational interaction from the Kerr black hole. It is found that the radiation is not exactly thermal, and because the derivation obeys conservation laws, the non-thermal Hawking radiation can carry information from the black hole. So it can be used to explain the black hole information paradox, and the process satisfies unitary.
Holley-Bockelmann, Kelly; Dunn, Glenna; Bellovary, Jillian M.; Christensen, Charlotte
2016-01-01
Luminous quasars detected at redshifts z > 6 require that the first black holes form early and grow to ~109 solar masses within one Gyr. Our work uses cosmological simulations to study the formation and early growth of direct collapse black holes. In the pre-reionization epoch, molecular hydrogen (H2) causes gas to fragment and form Population III stars, but Lyman-Werner radiation can suppress H2 formation and allow gas to collapse directly into a massive black hole. The critical flux required to inhibit H2 formation, Jcrit, is hotly debated, largely due to the uncertainties in the source radiation spectrum, H2 self-shielding, and collisional dissociation rates. Here, we test the power of the direct collapse model in a non-uniform Lyman-Werner radiation field, using an updated version of the SPH+N-body tree code Gasoline with H2 non-equilibrium abundance tracking, H2 cooling, and a modern SPH implementation. We vary Jcrit from 30 to 104 J21 to study the effect on seed black holes, focusing on black hole formation as a function of environment, halo mass, metallicity, and proximity of the Lyman-Werner source. We discuss the constraints on massive black hole occupation fraction in the quasar epoch, and implications for reionization, high-redshift X-ray background radiation, and gravitational waves.
Gravitational Radiation Characteristics of Nonspinning Black-Hole Binaries
Kelly, Barnard
2008-01-01
"We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source. applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the $\\ell = m$ modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model."
Gravitational radiation characteristics of nonspinning black-hole binaries
Energy Technology Data Exchange (ETDEWEB)
Kelly, B J; Baker, J G; Boggs, W D; Centrella, J M; Meter, J R van; McWilliams, S T, E-mail: bernard.j.kelly@nasa.go, E-mail: john.g.baker@nasa.go, E-mail: william.d.boggs@nasa.go, E-mail: joan.m.centrella@nasa.go, E-mail: james.r.vanmeter@nasa.go, E-mail: sean.t.mcwilliams@nasa.go [NASA Goddard Space Flight Center, Greenbelt MD 20771 (United States)
2009-03-01
We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source, applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the l = m modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Gravitational radiation characteristics of nonspinning black-hole binaries
International Nuclear Information System (INIS)
We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source, applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the l = m modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Dynamical Casimir effect and the black body spectrum
International Nuclear Information System (INIS)
Creation of scalar massless particles in two-dimensional Minkowski space time-as predicted by the dynamical Casimir effect-is studied for the case of a semitransparent mirror initially at rest, then accelerating for some finite time, along a specified trajectory, and finally moving with constant velocity. When the reflection and transmission coefficients are those in the model proposed by Barton, Calogeracos and Nicolaevici [r(w) = -iα/(ω + iα) and s(w) = ω/(ω + iα), with α ≥ 0], the Bogoliubov coefficients on the back side of the mirror can be computed exactly. This allows us to prove that, when α is very large (case of an ideal, perfectly reflecting mirror) a thermal emission of scalar massless particles obeying Bose-Einstein statistics is radiated from the mirror (a black body radiation), in accordance with previous results in the literature. However, when α is finite (semitransparent mirror, a physically realistic situation) the striking result is obtained that the thermal emission of scalar massless particles obeys Fermi-Dirac statistics. Possible consequences of this result are envisaged. (fast track communication)
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Crepin, Kofane Timoleon
2016-01-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Thomas, Bouetou Bouetou; Kofane, Timoleon Crepin
2015-10-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.
Radiation spectrum of a high-dimensional rotating black hole
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
This study extends the classical Damour-Ruffini method and discusses Hawking radiation in a (n + 4)-dimensional rotating black hole. Under the condition that the total energy and angular momentum of spacetime are conservative, but angular momentum a = J/M of unit mass of the black hole is variable, taking into consideration the reaction of the radiation of the particle to the spacetime, a new Tortoise coordinate transformation and discuss the black hole radiation spectrum is discussed. The radiation spectrum that satisfies the unitary principle in the general case is derived.
Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly
Institute of Scientific and Technical Information of China (English)
Peng Jun-Jin; Wu Shuang-Qing
2008-01-01
This paper derives the Hawking flux from the Schwarzschild black hole with a global monopole by using Robinson and Wilczek's method.Adopting a dimensional reduction technique, it can describe the effective quantum field in the (3+1)-dimensional global monopole background by an infinite collection of the (1+1)-dimensional maesless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)-dimensional black body radiation at the Hawking temperature.
Tunneling Radiation of Massive Vector Bosons from Dilaton Black Holes
Li, Ran; Zhao, Jun-Kun; Wu, Xing-Hua
2016-07-01
It is well known that Hawking radiation can be treated as a quantum tunneling process of particles from the event horizon of black hole. In this paper, we attempt to apply the massive vector bosons tunneling method to study the Hawking radiation from the non-rotating and rotating dilaton black holes. Starting with the Proca field equation that govern the dynamics of massive vector bosons, we derive the tunneling probabilities and radiation spectrums of the emitted vector bosons from the static spherical symmetric dilatonic black hole, the rotating Kaluza—Klein black hole, and the rotating Kerr—Sen black hole. Comparing the results with the blackbody spectrum, we satisfactorily reproduce the Hawking temperatures of these dilaton black holes, which are consistent with the previous results in the literature. Supported by National Natural Science Foundation of China under Grant No. 11205048
Hawking radiation from covariant anomalies in (2+1)-dimensional black holes
International Nuclear Information System (INIS)
In an insightful approach, Robinson and Wilczek proposed that Hawking radiation can be obtained as the compensation of a breakdown of general covariance and gauge invariance and the radiation is a black body radiation at Hawking temperature. We apply this method to two types of black holes in three-dimensional spacetime, both of which have the form of a metric such that the tt component of the metric is not inverse of the rr component of the metric. The first one is the warped AdS3 black hole in three-dimensional topologically massive gravity with the negative cosmological constant, and the second one is the charged rotating black hole in three dimensions.
Quantum Radiation of Dirac Particles in General Nonstationary Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiation of Dirac particles in general nonstationary black holes in the general case is investigated by using the method of generalized tortoise coordinate transformation and considering simultaneously the asymptotic behaviors of the first order and second order forms of Dirac equation near the event horizon. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we give a general expression of the new extra coupling effect in thermal radiation spectrum of Dirac particles which is absent from the thermal radiation spectrum of scalar particles. Also, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation in the case of scalar particles, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of scalar particles in non-thermal radiation for general nonstationary black holes.
Characteristics of Quantum Radiation of General Nonstationary Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiative characteristics of general nonstationary black holes in the general case are investigated by using the method of generalized tortoise coordinate transformation. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we discover that there is a certain relationship that is ignored before between thermal radiation and non-thermal radiation of black holes, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in non-thermal radiation for slowly varying nonstationary black holes. Also, we show that the deduced general results can be applied to different concrete conditions.
Numerical models of black body dominated GRBs: II. Emission properties
Cuesta-Martínez, Carlos F; Mimica, Petar; Thöne, Christina C; de Ugarte-Postigo, Antonio
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated (BBD) gamma-ray bursts (GRBs), long lasting events characterized by the presence of a significant thermal component trailing the GRB prompt emission, and also by an absence of a traditional afterglow. GRB 101225A, the Christmas Burst, is a prototype of such class. It has been suggested that BBD-GRBs could be observed after a merger in a binary system consisting of a neutron star and a Helium core of a main sequence star. Using detailed relativistic hydrodynamic numerical simulations we model the propagation of ultrarelativistic jets through the environments created by such mergers. In this paper we focus on explaining the emission properties of the jet evolution computing the whole radiative signature (both thermal and non-thermal) of the jet dynamical evolution. A comprehensive parameter study of the jet/environment interaction has been performed and synthetic spectra and light curves are compared with the observational data...
Thermal radiation and nonthermal radiation of the slowly changing dynamic Kerr-Newman black hole
Institute of Scientific and Technical Information of China (English)
Meng Qing-Miao; Wang Shuai; Jiang Ji-Jian; Deng De-Li
2008-01-01
Using the related formula of dynamic black hole, we have calculated the instantaneous radiation energy density of the slowly changing dynamic Kerr-Newman black hole. It is found that the instantaneous radiation energy density of a black hole is always proportional to the quartic of the temperature of the event horizon in the same direction. By using the Hamilton-Jacobin equation of scalar particles in the curved spacetime, the spontaneous radiation of the slowly changing dynamic Kerr-Newman black hole is studied. The energy condition for the occurrence of the spontaneous radiation is obtained.
Redshifting of cosmological black bodies in BSBM varying-alpha theories
Barrow, John D
2014-01-01
We analyse the behaviour of black-body radiation in theories of electromagnetism which allow the electron charge and the fine structure constant to vary in space and time. We show that such theories can be expressed as relativistic generalizations of a conventional dielectric. By making the appropriate definition of the vector potential and associated gauge transformations, we can identify the equivalent of the electric and displacement fields, $\\mathbf{E}$ and $\\mathbf{D}$, as well as the magnetic $ \\mathbf{B}$ and $\\mathbf{H}$ fields. We study the impact of such dielectrics on the propagation of light in the so-called BSBM theory and conclude that no changes are created to the standard cosmological evolution of the temperature and energy-density of black-body radiation.
Hawking Radiation of Grumiller Black Hole
Sakalli, I
2014-01-01
In this paper, we consider the relativistic Hamilton-Jacobi (HJ) equation and study the Hawking radiation (HR) of scalar particles from uncharged Grumiller black hole (GBH) which is affordable for testing in astrophysics. GBH is also known as Rindler modified Schwarzschild BH. Our aim is not only to investigate the effect of the Rindler parameter a on the Hawking temperature ($T_{H}$), but to examine whether there is any discrepancy between the computed horizon temperature and the standard $T_{H}$ as well. For this purpose, in addition to its naive coordinate system, we study on the three regular coordinate systems which are Painleve-Gullstrand (PG), ingoing Eddington-Finkelstein (IEF) and Kruskal-Szekeres (KS) coordinates. In all coordinate systems, we calculate the tunneling probabilities of incoming and outgoing scalar particles from the event horizon by using the HJ equation. It has been shown in detail that the considered HJ method is concluded with the conventional $T_{H}$ in all these coordinate system...
Note on black hole radiation spectrum in Loop Quantum Gravity
Diaz-Polo, Jacobo
2007-01-01
Recent detailed analysis within the Loop Quantum Gravity calculation of black hole entropy show a stair-like structure in the behavior of entropy as a function of horizon area. The non-trivial distribution of the degeneracy of the black hole horizon area eigenstates is at the origin of this behavior. This degeneracy distribution is analyzed and a phenomenological model is put forward to study the possible implications of this distribution in the black hole radiation spectrum.
Hawking radiation of Dirac particles from black strings
Ahmed, Jamil; Saifullah, K.
2011-08-01
Hawking radiation has been studied as a phenomenon of quantum tunneling in different black holes. In this paper we extend this semi-classical approach to cylindrically symmetric black holes. Using the Hamilton-Jacobi method and WKB approximation we calculate the tunneling probabilities of incoming and outgoing Dirac particles from the event horizon and find the Hawking temperature of these black holes. We obtain results both for uncharged as well as charged particles.
Hawking radiation of Dirac particles from black strings
Ahmed, Jamil
2011-01-01
Hawking radiation has been studied as a phenomenon of quantum tunneling in different black holes. In this paper we extend this semi-classical approach to cylindrically symmetric black holes. Using the Hamilton-Jacobi method and WKB approximation we calculate the tunneling probabilities of incoming and outgoing Dirac particles from the event horizon and find the Hawking temperature of these black holes. We obtain results both for uncharged as well as charged particles.
The fate of radiating black holes in noncommutative geometry
Piero NicoliniStefan I., Ljubljana & Turin Poly. & INFN, Trieste; Anais SmailagicINFN, Trieste; Euro SpallucciTrieste U. & INFN, Trieste
2014-01-01
We investigate the behavior of a radiating Schwarzschild black hole toy-model in a 2D noncommutative spacetime. It is shown that coordinate noncommutativity leads to: i) the existence of a minimal non-zero mass to which black hole can shrink; ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing terminal pha...
A model of radiating black hole in noncommutative geometry
Nicolini, Piero
2005-01-01
The phenomenology of a radiating Schwarzschild black hole is analyzed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: i) the existence of a minimal non-zero mass to which black hole can shrink; ii) a finite maximum temperature that the black hole can reach before cooli...
Black Hole Growth from Cosmological N-body Simulations
Micic, Miroslav; Sigurdsson, Steinn
2008-01-01
(Abridged) We use high resolution cosmological N-body simulations to study the growth of intermediate to supermassive black holes from redshift 49 to zero. We track the growth of black holes from the seeds of population III stars to black holes in the range of 10^3 < M < 10^7 Msun -- not quasars, but rather IMBH to low-mass SMBHs. These lower mass black holes are the primary observable for the Laser Interferometer Space Antenna (LISA). The large-scale dynamics of the black holes are followed accurately within the simulation down to scales of 1 kpc; thereafter, we follow the merger analytically from the last dynamical friction phase to black hole coalescence. We find that the merger rate of these black holes is R~25 per year between 8 < z < 11 and R = 10 per year at z=3. Before the merger occurs the incoming IMBH may be observed with a next generation of X-ray telescopes as a ULX source with a rate of about ~ 3 - 7 per year for 1 < z < 5. We develop an analytic prescription that captures the ...
Black-body laws derived from a minimum knowledge of Physics
A. G. AgneseINFN; La Camera, M.; E. Recami(INFN)
2015-01-01
Starting from the knowledge of the four fundamental quantities length L, mass M, time T, absolute temperature $\\theta$ and accepting the validity of Gauss's law in all dimensions, we generalize, by the theory of physical dimensions, the expression of the Stephan-Boltzmann law and of the Planck's formula for the black-body radiation to a spacetime with one time and n spatial coordinates. In the particular case n=3 we shall recover the known results.
Hawking radiation from acoustic black holes in two space dimensions
Eskin, Gregory
2016-01-01
We study the Hawking radiation from rotating acoustic black hole. We follow the approach of T.Jacobson and W.Unruh, although our approach differs in details. We also treat the case of variable velocity of the background flow.
Tidal interaction of black holes and Newtonian viscous bodies
Poisson, Eric
2009-01-01
The tidal interaction of a (rotating or nonrotating) black hole with nearby bodies produces changes in its mass, angular momentum, and surface area. Similarly, tidal forces acting on a Newtonian, viscous body do work on the body, change its angular momentum, and part of the transferred gravitational energy is dissipated into heat. The equations that describe the rate of change of the black-hole mass, angular momentum, and surface area as a result of the tidal interaction are compared with the equations that describe how the tidal forces do work, torque, and produce heat in the Newtonian body. The equations are strikingly similar, and unexpectedly, the correspondence between the Newtonian-body and black-hole results is revealed to hold in near-quantitative detail. The correspondence involves the combination k_2 \\tau of ``Love quantities'' that incorporate the details of the body's internal structure; k_2 is the tidal Love number, and \\tau is the viscosity-produced delay between the action of the tidal forces a...
Possible suppression of Hawking radiation from microscopic black holes
Ahn, Doyeol
2010-01-01
Microscopic black holes with mass in the TeV range to be produced in the Large Hadron Collider (LHC) should undergo the prompt and quasi-thermal evaporation by emitting Hawking radiation. If this Hawking decay is not universal, some black holes can live long enough to penetrate into the Earth and grow dangerously. At present, the effects of black hole internal quantum state evolution on the evaporation are not well understood. This study shows that Hawking decay could be suppressed when the black hole internal matter state is in the coherent state. In this case, black holes created in the LHC may live long enough to grow catastrophically. The condition to avoid this catastrophic situation is also discussed. Our results demonstrate that the black hole evaporation is strongly dependent on the black hole internal quantum state and its evolution.
Unthermal Hawking Radiation from a General Stationary Black Hole
Institute of Scientific and Technical Information of China (English)
ZHANG Gui-Qing; ZHANG Yong-Ping; YANG Qiu-Ying; DAI Qian; CHEN Tian-Lun; LIU Wen-Biao
2008-01-01
Using Damour-Ruffini's method, Hawking radiation from a general stationary black hole is investigated again deeply. Considering the back reaction of the particle to the space-time and energy conservation, we find that the radiation is not exactly thermal and can take out information from the black hole. This can be used to explain the information loss paradox, and the result is consistent with the works finished before.
Mergers of nonspinning black-hole binaries: Gravitational radiation characteristics
Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; van Meter, James R.
2008-01-01
We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of nonspinning black holes, based on numerical simulations of systems varying from equal-mass to a 6:1 mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an ...
Doing it with Mirrors Classical analogues for Black Hole radiation
Srinivasan, K
1998-01-01
We construct analogues for the quantum phenomena of black hole radiation in the context of {\\it classical field theory}. Hawking radiation from a (radially) collapsing star is mathematically equivalent to radiation from a mirror moving along a specific trajectory in Minkowski spacetime. We construct a classical analogue for this quantum phenomenon and use it to construct a classical analogue for black hole radiation. The radiation spectrum in quantum field theory has the power spectrum as its classical analogue. Monochromatic light is continually reflected off a moving mirror or the silvered surface of a collapsing star.The reflected light is fourier analysed by the observer and the power spectrum is constructed. For a mirror moving along the standard black hole trajectory,it is seen that the power spectrum has a ``thermal'' nature. Mirror-observer configurations like an inertial mirror observed in an accelerated observer's frame and an accelerated mirror observed in a Rindler frame are investigated and condi...
Tunnelling Effect and Hawking Radiation from a Vaidya Black Hole
Institute of Scientific and Technical Information of China (English)
ZHANG Jing-Yi; ZHAO Zheng
2006-01-01
@@ We extend Parikh's study to the non-stationary black hole. As an example of the non-stationary black hole, we investigate the tunnelling effect and Hawking radiation from a Vaidya black hole whose Bondi mass is identical to its mass parameter. The Hawking radiation is considered as a tunnelling process across the event horizon and we calculate the tunnelling probability. It is found that the result is different from Parikh's study because drH/dv is the function of Bondi mass m(v).
A model of radiating black hole in noncommutative geometry
Energy Technology Data Exchange (ETDEWEB)
Nicolini, Piero [Dipartimento di Matematica e Informatica, Universita di Trieste, Trieste (Italy); Institut Jozef Stefan, Ljubljana (Slovenia); Dipartimento di Matematica, Politecnico di Torino, Turin (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy)
2005-09-30
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
A model of radiating black hole in noncommutative geometry
International Nuclear Information System (INIS)
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
The classical essence of black hole radiation
Nouri-Zonoz, M
1998-01-01
We show that the mathematics of Hawking process can be interpreted classically as the Fourier analysis of an exponentially redshifted wave mode which scatters off the black hole and travels to infinity at late times. We use this method to derive the Planckian power spectrum for Schwarzchild, Reissner-Nordstrom and Kerr black holes.
Dilaton Black Hole Tunneling Radiation in de Sitter Universe
Institute of Scientific and Technical Information of China (English)
LI Gu-Qiang
2009-01-01
The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh-Wilczek's method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory.
Effective-one-body modeling of precessing black hole binaries
Taracchini, Andrea; Babak, Stanislav; Buonanno, Alessandra
2016-03-01
Merging black hole binaries with generic spins that undergo precessional motion emit complicated gravitational-wave signals. We discuss how such waveforms can be accurately modeled within an effective-one-body approach by (i) exploiting the simplicity of the signals in a frame that corotates with the orbital plane of the binary and (ii) relying on an accurate model of nonprecessing black hole binaries. The model is validated by extensive comparisons to 70 numerical relativity simulations of precessing black hole binaries and can generate inspiral-merger-ringdown waveforms for mass ratios up to 100 and any spin configuration. This work is an essential tool for studying and characterizing candidate gravitational-wave events in science runs of advanced LIGO.
Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)
Cavaglia, Marco
2003-01-01
If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this paper we study some experimental signatures of black hole production in TeV-gravity theories. In contrast with the usual lore, we show that the black hole energy loss in the bulk during the Hawking evaporation phase may be of the same order of the energy radiated into the brane. We investigate in detail the multiplicity of the decay products of black hole evaporation. We fi...
GUP Assisted Hawking Radiation of Rotating Acoustic Black Holes
Sakalli, I; Jusufi, K
2016-01-01
Recent studies [J. Steinhauer, Nature Phys., $\\textbf{10}$, 864 (2014); Phys. Rev. D $\\textbf{92}$, 024043 (2015)] provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
GUP assisted Hawking radiation of rotating acoustic black holes
Sakalli, I.; Övgün, A.; Jusufi, K.
2016-10-01
Recent studies (Steinhauer in Nat. Phys. 10:864, 2014, Phys. Rev. D 92:024043, 2015) provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
Matter flows around black holes and gravitational radiation
Papadopoulos, Philippos; Font, Jose A.
1998-01-01
We develop and calibrate a new method for estimating the gravitational radiation emitted by complex motions of matter sources in the vicinity of black holes. We compute numerically the linearized curvature perturbations induced by matter fields evolving in fixed black hole backgrounds, whose evolution we obtain using the equations of relativistic hydrodynamics. The current implementation of the proposal concerns non-rotating holes and axisymmetric hydrodynamical motions. As first applications...
Applications of geometric algebra to black holes and Hawking radiation
Setiawan, S.
2004-01-01
We discuss the applications of Gauge Theory of Gravity (GTG) within the language of geometric algebra to black holes and Hawking radiation. Applications include the Unruh effect, the Dirac and Klein-Gordon equations in several backgrounds, such as the de Sitter and Rindler metrics as well as spherically and axially black hole backgrounds. The analysis is also generalised to allow the presence of magnetic monopoles. We rederive the Hawking temperature for all cases. The derivation of both the ...
Modeling gravitational radiation from coalescing binary black holes
Baker, J; Loustó, C O; Takahashi, R
2002-01-01
With the goal of bringing theory, particularly numerical relativity, to bear on an astrophysical problem of critical interest to gravitational wave observers we introduce a model for coalescence radiation from binary black hole systems. We build our model using the "Lazarus approach", a technique that bridges far and close limit approaches with full numerical relativity to solve Einstein equations applied in the truly nonlinear dynamical regime. We specifically study the post-orbital radiation from a system of equal-mass non-spinning black holes, deriving waveforms which indicate strongly circularly polarized radiation of roughly 3% of the system's total energy and 12% of its total angular momentum in just a few cycles. Supporting this result we first establish the reliability of the late-time part of our model, including the numerical relativity and close-limit components, with a thorough study of waveforms from a sequence of black hole configurations varying from previously treated head-on collisions to rep...
Quantum tunnelling for Hawking radiation from a dynamical Black Hole
Mazumder, Nairwita; Chakraborty, Subenoy
2011-01-01
The paper deals with Hawking radiation related to non-static spherically symmetric black hole. Quantum corrections are incorporated using Hamilton-Jacobi method beyond semi-classical approximation. It is found that different order correction terms satisfy identical differential equation as the semiclassical action and are solved by a typical technique. It has been shown that with proper choice of the proportionality factors, one loop back reaction effect in the space time can be obtained. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature.
Inferring black hole charge from backscattered electromagnetic radiation
Crispino, Luís C B; Higuchi, Atsushi; de Oliveira, Ednilton S
2014-01-01
We compute the scattering cross section of Reissner-Nordstr\\"om black holes for the case of an incident electromagnetic wave. We describe how scattering is affected by both the conversion of electromagnetic to gravitational radiation, and the parity-dependence of phase shifts induced by the black hole charge. The latter effect creates a helicity-reversed scattering amplitude that is non-zero in the backward direction. We show that from the character of the electromagnetic wave scattered in the backward direction it is possible, in principle, to infer if a static black hole is charged.
Stimulated emission and Hawking radiation in black hole analogues
Belgiorno, F
2016-01-01
Stimulated emission by black holes is discussed in light of the analogue gravity program. We first consider initial quantum states containing a definite number of particles, and then we take into account the case where the initial state is a coherent state. The latter case is particularly significant in the case where Hawking radiation is studied in dielectric black holes, and the emission is stimulated by a laser probe. We are particularly interested in the case of the electromagnetic field, for which stimulated radiation is calculated too.
Hawking radiation of Kerr-Newman black hole in different tortoise coordinate transformations
Ibungochouba Singh, T.
2013-10-01
Hawking radiation effect of Maxwell’s electromagnetic fields in the Kerr-Newman black hole space-time is investigated using two different tortoise coordinate transformations. It has been shown that the new tortoise coordinate transformation produces constant term ξ in the expression of surface gravity and Hawking temperature. If ξ is set to zero, the surface gravity and Hawking temperature will be equal to those obtained from the old tortoise coordinate transformation. This indicates that new transformation is more reliable and accurate. The black body radiant spectrum of photon displays a new spin-rotation coupling effect.
Black Sun: Ocular Invisibility of Relativistic Luminous Astrophysical Bodies
Lee, Jeffrey S
2015-01-01
The relativistic Doppler shifting of visible electromagnetic radiation to beyond the human ocular range reduces the incident radiance of the source. Consequently, luminous astrophysical bodies (LABs) can be rendered invisible with sufficient relativistic motion. This paper determines the proper distance as a function of relativistic velocity at which a luminous object attains ocular invisibility.
How black holes get their kicks: Radiation recoil in binary black hole mergers
Hughes, S A; Holz, D E; Hughes, Scott A.; Favata, Marc; Holz, Daniel E.
2004-01-01
Gravitational waves from the coalescence of binary black holes carry linear momentum, causing center of mass recoil. This ``radiation rocket'' has important implications for systems with escape speeds of order the recoil velocity. We describe new recoil calculations using high precision black hole perturbation theory to estimate the magnitude of the recoil for the slow ``inspiral'' coalescence phase; coupled with a cruder calculation for the final ``plunge'', we estimate the total recoil imparted to a merged black hole. We find that velocities of many tens to a few hundred km/sec can be achieved fairly easily. The recoil probably never exceeds about 500 km/sec.
Indian Academy of Sciences (India)
W. X. Zhong
2014-09-01
In this paper, we use the canonical ensemble model to discuss the radiation of a Schwarzschild–de Sitter black hole on the black hole horizon. Using this model, we calculate the probability distribution from function of the emission shell. And the statistical meaning which compare with the distribution function is used to investigate the black hole tunnelling radiation spectrum.We also discuss the mechanism of information flowing from the black hole.
Quantum Tunneling Radiation of Kerr-NUT Black Hole
Institute of Scientific and Technical Information of China (English)
LI Hui-Ling; YANG Shu-Zheng; QI De-Jiang
2006-01-01
Based on particles in a dynamical geometry, extending the Parikh's method of quantum tunneling radiation,we deeply investigate the quantum tunneling radiation of Kerr-NUT black hole. When self-gravitating action, energyconservation, and angular momentum conservation are taken into account, the emission rate of the particle on the event horizon is related to the change of Bekenstein-Hawking entropy and the emission spectrum is not precisely thermal, but is consistent with an underlying unitary theory.
Hawking Radiation via Tunnelling from Arbitrarily Dimensional Schwarzschild Black Holes
Institute of Scientific and Technical Information of China (English)
REN Jun; ZHAO Zheng; GAO Chang-Jun
2005-01-01
@@ We extend Parikh's recent work to the arbitrarily dimensional Schwarzschild black holes whose Arnowitt-DeserMisner (ADM) mass is identical to its mass parameter. We view Hawking radiation as a tunnelling process across the event horizon. From the tunnelling probability we also find a leading correction to the semiclassical emission rate. The result consists with an underlying unitary theory.
Hawking radiation via tunnelling from general stationary axisymmetric black holes
Institute of Scientific and Technical Information of China (English)
Zhang Jing-Yi; Fan Jun-Hui
2007-01-01
Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated,separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.
On Hawking Radiation of 3D Rotating Hairy Black Holes
Belhaj, A.; Chabab, M.; Moumni, H. EL; Masmar, K.; Sedra, M. B.
2015-01-01
We study the Hawking radiation of 3D rotating hairy black holes. More concretely, we compute the transition probability of a bosonic and fermionic particle in such backgrounds. Thew, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hair B and the rotation parameter a control such a probability.
Harms, Enno; Bernuzzi, Sebastiano; Nagar, Alessandro
2016-01-01
We consider a spinning test-body in circular motion around a nonrotating black hole and analyze different prescriptions for the body's dynamics. We compare, for the first time, the Mathisson-Papapetrou formalism under the Tulczyjew spin-supplementary-condition (SSC), the Pirani SSC and the Ohashi-Kyrian-Semerak SSC, and the spinning particle limit of the effective-one-body Hamiltonian of [Phys.~Rev.~D.90,~044018(2014)]. We analyze the four different dynamics in terms of the ISCO shifts and in terms of the coordinate invariant binding energies, separating higher-order spin contributions from spin-orbit contributions. The asymptotic gravitational wave fluxes produced by the spinning body are computed by solving the inhomogeneous $(2+1)D$ Teukolsky equation and contrasted for the different cases. For small orbital frequencies $\\Omega$, all the prescriptions reduce to the same dynamics and the same radiation fluxes. For large frequencies, ${x \\equiv (M \\Omega)^{2/3} >0.1 }$, where $M$ is the black hole mass, and ...
[Stereotactic body radiation therapy for spinal metastases].
Pasquier, D; Martinage, G; Mirabel, X; Lacornerie, T; Makhloufi, S; Faivre, J-C; Thureau, S; Lartigau, É
2016-10-01
After the liver and lungs, bones are the third most common sites of cancer metastasis. Palliative radiotherapy for secondary bone tumours helps relieve pain, improve the quality of life and reduce the risk of fractures. Stereotactic body radiotherapy can deliver high radiation doses with very tight margins, which has significant advantages when treating tumours close to the spinal cord. Strict quality control is essential as dose gradient at the edge of the spinal cord is important. Optimal schedule is not defined. A range of dose-fractionation schedules have been used. Pain relief and local control are seen in over 80%. Toxicity rates are low, although vertebral fracture may occur. Ongoing prospective studies will help clarify its role in the management of oligometastatic patients. PMID:27614511
Dynamics around black holes: Radiation Emission and Tidal Effects
Brito, Richard
2012-01-01
In this thesis we study several dynamical processes involving black holes in four and higher dimensions. First, using perturbative techniques, we compare the massless and massive scalar radiation emitted by a particle radially infalling into a Schwarzchild black hole. We show that the late-time waveform of massive scalar perturbations is dominated by a universal oscillatory decaying tail, which appears due to curvature effects. We also show that the energy spectrum is in perfect agreement with a ZFL calculation once no-hair properties of black holes are taken into account. In the second part, we study the phenomenon of superradiance in higher dimensions and conjecture that the maximum energy extracted from a rotating black hole can be understood in terms of the ergoregion proper volume. We then study some consequences of superradiance in the dynamics of moons orbiting around higher-dimensional rotating black holes. In four-dimensional spacetime, moons around black holes generate low-amplitude tides, and the e...
Gravitational Radiation of Binaries Coalescence into Intermediate Mass Black Holes
Institute of Scientific and Technical Information of China (English)
李瑾; 仲元红; 潘宇
2012-01-01
This paper discusses the gravitation waveforms of binaries coalescence into intermediate mass black holes （about 30 times of the solar mass）. We focus on the non-spinning intermediate mass black hole located less than 100 Mpc from earth. By comparing two simulation waveforms （effective one body numerical relativity waveform （EOBNR）, phenomenological waveform）, we discuss the relationship between the effective distance and frequency; and through analyzing large amounts of data in event, we find that the phenomenological waveform is much smoother than EOBNR waveform, and has higher accuracy at the same effective distance.
Hawking Radiation of Photons in a Vaidya-de Sitter Black Hole
Wu, S Q
2002-01-01
Hawking evaporation of photons in a Vaidya-de Sitter black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the time. It is shown that Hawking radiation of photons exists only for the complex Maxwell scalar $\\phi_0$ in the advanced Eddington-Finkelstein coordinate system. This asymmetry of Hawking radiation for different components of Maxwell fields probably arises from the asymmetry of spacetime in the advanced Eddington-Finkelstein coordinate system. It is shown that the black body radiant spectrum of photons resembles that of Klein-Gordon particles. PACS numbers: 04.70.Dy, 97.60.Lf
Radiative Shocks in Rotating Accretion Flows around Black Holes
Okuda, T; Toscano, E; Molteni, D
2004-01-01
It is well known that the rotating accretion flows around black holes form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. We examine numerically such shock waves in 1D and 2D accretion flows, taking account of the cooling and heating of gas and the radiation transport. The numerical results show that the shock location shifts outward compared with that in the adiabatic solutions and that the more rarefied ambient density leads to the more outward shock position. In the 2D-flow, we find an intermediate frequency QPO behavior of the shock location as is observed in the black hole candidate GRS 1915+105.
A Model For The Absorption Of Thermal Radiation By Gold-Black
Quinlan, Brendan Robert
2015-01-01
The work presented here addresses an important topic in thermal radiation detection when gold-black is used as an absorber. Sought is a model to simulate the absorption of thermal radiation by gold-black. Fractal geometry is created to simulate the topology of gold-black. Then electrical circuits based on the topology are identified that capture the physics of the interaction between the gold-black material and incident electro-magnetic radiation. Parameters of the model are then adj...
Body fat distribution and perception of desirable female body shape by young black men and women.
Singh, D
1994-11-01
The relation between body fat distribution as measured by waist-to-hip ratio (WHR) and perception of desirable female body shape was investigated in college-age black men and women. Subjects judged attractiveness, various personal qualities, and desirability for long-term relationships of 12 line drawings of female figures that represented three body weight categories (normal, underweight, and overweight) and four levels of WHRs (0.7, 0.8, 0.9, and 1.0). Judgments of attractiveness and desirability for long-term relationships were affected by body weight and the size of the WHR. Both male and female subjects ranked normal weight figures with 0.7 and 0.8 WHR as more attractive and desirable for long-term relationships; neither underweight nor overweight figures, irrespective of WHR size, were assigned high ranking for these variables. These findings do not support the notion that black young men and women find overweight female figures as desirable and attractive. PMID:7833963
Hawking radiation of a uniformly accelerating black hole
Institute of Scientific and Technical Information of China (English)
Ren Jun; Cao Jiang-Ling; Zhao Zheng
2006-01-01
In this paper, we study the Hawking radiation via tunnelling from a uniformly accelerating black hole. Although the Bekenstein-Hawking entropy is proportional also to the area of the event horizon, the radius of it, rH, is a function of θ, which leads to the difficulties in the calculation of the emission rate. In order to overcome the mathematical difficulties, we propose a new technique to calculate the emission rate and the result obtained is reasonable.
General Relativistic Radiative Transfer: Applications to Black-Hole Systems
Wu, Kinwah; Fuerst, Steven V.; Mizuno, Yosuke; Nishikawa, Ken-Ichi; Branduardi-Raymont, Graziella; Lee, Khee-Gan
2007-01-01
We present general relativistic radiation transfer formulations which include opacity effects due to absorption, emission and scattering explicitly. We consider a moment expansions for the transfer in the presence of scattering. The formulation is applied to calculation emissions from accretion and outflows in black-hole systems. Cases with thin accretion disks and accretion tori are considered. Effects, such as emission anisotropy, non-stationary flows and geometrical self-occultation are investigated. Polarisation transfer in curved space-time is discussed qualitatively.
Hawking Radiation as Quantum Tunneling from Noncommutative Schwarzschild Black Hole
Nozari, Kourosh; Mehdipour, S. Hamid
2008-01-01
We study tunneling process through quantum horizon of a Schwarzschild black hole in noncommutative spacetime. This is done by considering the effect of smearing of the particle mass as a Gaussian profile in flat spacetime. We show that even in this noncommutative setup there will be no correlation between the different modes of radiation which reflects the fact that information doesn't come out continuously during the evaporation process at least at late-time. However, due to spacetime noncom...
Ruling out stray thermal radiation in analogue black holes
Doukas, Jason; Adesso, Gerardo; Fuentes, Ivette
2014-01-01
Experimental searches for the thermal radiation from analogue black holes require the measurement of very low temperatures in regimes where other thermal noises may interfere or even mimic the sought-after effect. In this letter, we parameterize the family of bosonic thermal channels which give rise to such thermal effects and show that by use of coherent states and homodyne detection one can rule out the non-Hawking contributions and identify those candidate sources which arise from Hawking-...
Radiatively Driven Winds from Effective Boundary Layer around Black Holes
Indian Academy of Sciences (India)
Indranil Chattopadhyay; Sandip K. Chakrabarti
2002-03-01
Matter accreting onto black holes suffers a standing or oscillating shock wave in much of the parameter space. The post-shock region is hot, puffed up and reprocesses soft photons from a Keplerian disc to produce the characteristic hard tail of the spectrum of accretion discs. The post-shock torus is also the base of the bipolar jets. We study the interaction of these jets with the hard photons emitted from the disc. We show that radiative force can accelerate outflows but the drag can limit the terminal speed. We introduce an equilibrium speed eq as a function of distance, above which the flow will experience radiative deceleration.
Dirac Particles' Hawking Radiation from a Schwarzschild Black Hole
Institute of Scientific and Technical Information of China (English)
HE Xiao-Kai; LIU Wen-Biao
2007-01-01
@@ Considering energy conservation and the backreaction of particles to spacetime, we investigate the massless/massive Dirac particles' Hawking radiation from a Schwarzschild black hole. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the results obtained before. It satisfies the underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas the improved Damour-Ruffini method is more concise and understandable.
Stereotactic Body Radiation Therapy in Spinal Metastases
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Kamran A. [Mayo Medical School, College of Medicine, Mayo Clinic, Rochester, MN (United States); Stauder, Michael C.; Miller, Robert C.; Bauer, Heather J. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Rose, Peter S. [Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN (United States); Olivier, Kenneth R. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Brown, Paul D. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Brinkmann, Debra H. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Laack, Nadia N., E-mail: laack.nadia@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States)
2012-04-01
Purpose: Based on reports of safety and efficacy, stereotactic body radiotherapy (SBRT) for treatment of malignant spinal tumors was initiated at our institution. We report prospective results of this population at Mayo Clinic. Materials and Methods: Between April 2008 and December 2010, 85 lesions in 66 patients were treated with SBRT for spinal metastases. Twenty-two lesions (25.8%) were treated for recurrence after prior radiotherapy (RT). The mean age of patients was 56.8 {+-} 13.4 years. Patients were treated to a median dose of 24 Gy (range, 10-40 Gy) in a median of three fractions (range, 1-5). Radiation was delivered with intensity-modulated radiotherapy (IMRT) and prescribed to cover 80% of the planning target volume (PTV) with organs at risk such as the spinal cord taking priority over PTV coverage. Results: Tumor sites included 48, 22, 12, and 3 in the thoracic, lumbar, cervical, and sacral spine, respectively. The mean actuarial survival at 12 months was 52.2%. A total of 7 patients had both local and marginal failure, 1 patient experienced marginal but not local failure, and 1 patient had local failure only. Actuarial local control at 1 year was 83.3% and 91.2% in patients with and without prior RT. The median dose delivered to patients who experienced local/marginal failure was 24 Gy (range, 18-30 Gy) in a median of three fractions (range, 1-5). No cases of Grade 4 toxicity were reported. In 1 of 2 patients experiencing Grade 3 toxicity, SBRT was given after previous radiation. Conclusion: The results indicate SBRT to be an effective measure to achieve local control in spinal metastases. Toxicity of treatment was rare, including those previously irradiated. Our results appear comparable to previous reports analyzing spine SBRT. Further research is needed to determine optimum dose and fractionation to further improve local control and prevent toxicity.
Hydrodynamic and hydromagnetic stability of black holes with radiative transfer
Indian Academy of Sciences (India)
Roger Blandford; Jonathan C Mckinney; Nadia Zakamska
2011-07-01
Subrahmanyan Chandrasekhar (Chandra) was just eight years old when the ﬁrst astrophysical jet was discovered in M87. Since then, jets have been uncovered with a wide variety of sources including accretion disks orbiting stellar and massive black holes, neutron stars, isolated pulsars, -ray bursts, protostars and planetary nebulae. This talk will be primarily concerned with collimated hydromagnetic outﬂows associated with spinning, massive black holes in active galactic nuclei. Jets exhibit physical processes central to three of the major research themes in Chandrasekhar’s research career – radiative transfer, magnetohydrodynamics and black holes. Relativistic jets can be thought of as `exhausts’ from both the hole and its orbiting accretion disk, carrying away the energy liberated by the rotating spacetime and the accreting gas that is not radiated. However, no aspect of jet formation, propagation and radiation can be regarded as understood in detail. The combination of new -ray, radio and optical observations together with impressive advances in numerical simulation make this a good time to settle some long-standing debates.
Growth of massive black holes during radiatively inefficient accretion phases
Cao, X
2006-01-01
The massive black holes in most faint active galactic nuclei (AGNs) and even normal galaxies are still accreting gases, though their accretion rates are very low. Radiatively inefficient accretion flows (RIAFs) are supposed in these faint sources, which should radiate mostly in the hard X-ray band. We calculate the contribution to the X-ray background from both the bright AGNs and the RIAFs in faint AGNs/normal galaxies. Our calculations show that both the observed intensity and spectral shape of the XRB with an energy peak at ~30$ keV can be well reproduced without including the emission of Compton-thick AGNs, if the massive black holes in faint AGNs/normal galaxies are spinning rapidly with a~0.9 and accreting at rates ~1.0-3.0\\times 10^{-4}. It indicates that less than ~5 per cent of local massive black hole mass density was accreted during radiatively inefficient accretion phases, which is obviously only an upper limit, because Compton-thick AGNs have not been considered. If the same number of the Compton...
Accretion of radiation and rotating primordial black holes
Mahapatra, S.; Nayak, B.
2016-02-01
We consider rotating primordial black holes (PBHs) and study the effect of accretion of radiation in the radiation-dominated era. The central part of our analysis deals with the role of the angular momentum parameter on the evolution of PBHs. We find that both the accretion and evaporation rates decrease with an increase in the angular momentum parameter, but the rate of evaporation decreases more rapidly than the rate of accretion. This shows that the evaporation time of PBHs is prolonged with an increase in the angular momentum parameter. We also note that the lifetime of rotating PBHs increases with an increase in the accretion efficiency of radiation as in the case of nonrotating PBHs.
Oscillations of radiation pressure supported tori near black holes
Mazur, Grzegorz P; Sądowski, Aleksander; Mishra, Bhupendra; Kluźniak, Włodek
2015-01-01
We study the dynamics of radiation pressure supported tori around Schwarzschild black holes, focusing on their oscillatory response to an external perturbation. Using KORAL, a general relativistic radiation hydrodynamics code capable of modeling all radiative regimes from the optically thick to the optically thin, we monitor a sample of models at different initial temperatures and opacities, evolving them in two spatial dimensions for $\\sim 165$ orbital periods. The dynamics of models with high opacity is very similar to that of purely hydrodynamics models, and it is characterized by regular oscillations which are visible also in the light curves. As the opacity is decreased, the tori quickly and violently migrate towards the gas-pressure dominated regime, collapsing towards the equatorial plane. When the spectra of the $L_2$ norm of the mass density are considered, high frequency inertial-acoustic modes of oscillations are detected (with the fundamental mode at a frequency $68 M_{\\rm BH}^{-1}\\,\\rm Hz$), in c...
Rapid Black Hole Growth under Anisotropic Radiation Feedback
Sugimura, Kazuyuki; Yajima, Hidenobu; Omukai, Kazuyuki
2016-01-01
Rapid accretion of gases onto massive black holes (BHs) is considered to have played an important role in the growth of the observed high-redshift (z > 6) supermassive BHs. Here, we present the results of our two-dimensional radiation hydrodynamics simulations of rapidly accreting BHs under anisotropic radiation. We model the radiation from the central circum-BH accretion disk considering the shadowing effect by the outer part of the disk. We find that the flow structure reaches a steady state, which consists of a polar ionized outflowing region, where the gas is pushed outward by the super-Eddington radiation pressure, and an equatorial neutral inflowing region, where the gas falls toward the central BH in a Bondi-like accretion fashion without affected by radiation feedback. The resulting accretion rate is much higher than that in the case of isotropic radiation, and far exceeds the Eddington-limited rate and even reaches around the Bondi value. We find that the solid angle of the equatorial inflowing regio...
Dependence of the Black Body Force on Spacetime Geometry and Topology
Muniz, C R; Cunha, M S; Landim, R R; Filho, R N Costa
2015-01-01
In this manuscript we compute the corrections to the black body force due to spacetime geometry and topology. This recently discovered attractive force on neutral atoms is caused by the thermal radiation emitted from black bodies and here we investigate it in systems with spherical and cylindrical symmetries. For some astrophysical objects we find that the corrected force is greater than the flat case, showing that this kind of correction can be quite relevant when curved spaces are considered. Then we consider four cases: The Schwarzschild spacetime, the non-relativistic infinity cylinder, and both the static and stationary cosmic strings. For the spherically symmetric case we find that two corrections appear: One due to the gravitational modification of the temperature and the other due to the modification of the solid angle subtended by the atom. We apply the found results to a typical neutron star and to the Sun. For the cylindrical case, which is locally flat, no gravitational correction to the temperatu...
Webb, Jennifer B; Butler-Ajibade, Phoebe; Robinson, Seronda A
2014-09-01
The present study provided an initial evaluation of an affect regulation model describing the association between body dissatisfaction and two contemporary measures of positive body image among 247 Black college-bound older adolescent females. We further tested whether possessing a higher body mass index (BMI) would strengthen these associations. Self-reported height and weight were used to calculate BMI. Respondents also completed a culturally-sensitive figure rating scale along with assessments of body appreciation and body image flexibility. Results indicated a robust positive association between the two measures of positive body image; BMI was the strongest predictor of both body appreciation and body image flexibility with body size discrepancy (current minus ideal) contributing incremental variance to both models tested. Implications for improving our understanding of the association between positive and negative body image and bolstering positive body image to promote health-protective behaviors among Black young women at this developmental juncture are discussed. PMID:25079011
Webb, Jennifer B; Butler-Ajibade, Phoebe; Robinson, Seronda A
2014-09-01
The present study provided an initial evaluation of an affect regulation model describing the association between body dissatisfaction and two contemporary measures of positive body image among 247 Black college-bound older adolescent females. We further tested whether possessing a higher body mass index (BMI) would strengthen these associations. Self-reported height and weight were used to calculate BMI. Respondents also completed a culturally-sensitive figure rating scale along with assessments of body appreciation and body image flexibility. Results indicated a robust positive association between the two measures of positive body image; BMI was the strongest predictor of both body appreciation and body image flexibility with body size discrepancy (current minus ideal) contributing incremental variance to both models tested. Implications for improving our understanding of the association between positive and negative body image and bolstering positive body image to promote health-protective behaviors among Black young women at this developmental juncture are discussed.
On the origin of black hole evaporation radiation
International Nuclear Information System (INIS)
The physical basis underlying the black hole evaporation process is clarified by a calculation of the expectation value of the energy-momentum tensor for a massless scalar field in a completely general two dimensional collapse scenario. It is found that radiation is produced inside the collapsing matter which propagates both inwards and outwards. The ingoing component eventually emerges from the star after travelling through the centre. The outgoing energy flux appears at infinity as the evaporation radiation discovered by Hawking (Comm. Math. Phys.; 43: 199 (1975)). At late times, outside the star, the former component fades out exponentially, and the latter component approaches a value which is independent of the details of the collapse process. In the special case of a collapsing hollow, thin shell of matter, all the radiation is produced at the shell. These results are independent of regularization ambiguities, which enter only the static vacuum polarization terms in the energy-momentum tensor. The significance of an earlier remark about black hole explosions is discussed in the light of these results. (author)
Energy Crisis in Astrophysics (Black Holes vs. N-Body Metrics)
Alley, C O; Mizobuchi, Y; Yilmaz, H; Alley, Carroll O; Leiter, Darryl L; Mizobuchi, Yutaka; Yilmaz, Huseyin
1999-01-01
The recent observation of the gamma ray burster GRB 990123, requiring at least two solar masses of energy in gamma radiation alone, created an energy crisis in astrophysics (Schilling 1999). We discuss a theorem which states that, of all four-dimensional curved spacetime theories of gravity viable with respect to the four classical weak field tests, only one unique case, the Yilmaz theory, has interactive N-body (multiparticle) solutions and this unique case has no event horizons. The theorem provides strong theoretical support for Robertson's explanation of the large energy output of the gamma ray burster GRB 990123 (Robertson 1999b). This explanation requires a switch from black holes (a 1-body solution with horizon) to the case of horizon-free interactive N-body solutions. In addition to the good news that the long sought N-body solutions are found, this unique case enjoys further strong support from other areas of gravitational physics. This development does not rule out GRB models with beaming, which can...
Spherically Symmetric Static Solution for a Schwarzschild Black Hole with Its Hawking Radiation
Institute of Scientific and Technical Information of China (English)
HUANG Chao-Guang
2000-01-01
A black hole and its Hawking radiation may be in stable thermal equilibrium. In this letter, the static spherically symmetric numerical solution for a Schwarzschild black hole with its Hawking radiation are obtained. In the calculation, the equilibrium system is supposed to consist of a black hole, thermal radiation and a two-dimensional surface layer. The solutions obtained are compared with the York's back-reaction approach and the Zhao-Liu thermodynamic approach.
Decontamination of black pepper and red pepper by gamma radiation
International Nuclear Information System (INIS)
In the present work, it has been studied the decontamination of two types of spices (black pepper and red pepper) by gamma radiation. The initial microbial population of spices not treated is about 10 (7) to 10 (8) per gram. The population decrease exponentially with irradiation dose. By this, it has been established that a dose of 6 kGy reduces the microbial flora low than 10 (3) per gram. A total elimination of moulds is obtained at dose of 8 kGy
Mergers of Non-spinning Black-hole Binaries: Gravitational Radiation Characteristics
Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; vanMeter, James R.
2008-01-01
We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of non-spinning black holes, based on numerical simulations of systems varying from equal-mass to a 6:1 mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an interpretation of the waveforms in terms of an implicit rotating source. This interpretation applies uniformly to the full wavetrain, from inspiral through ringdown. We emphasize strong relationships among the l = m modes that persist through the full wavetrain. Exploring the structure of the waveforms in more detail, we conduct detailed analytic fitting of the late-time frequency evolution, identifying a key quantitative feature shared by the l = m modes among all mass-ratios. We identify relationships, with a simple interpretation in terms of the implicit rotating source, among the evolution of frequency and amplitude, which hold for the late-time radiation. These detailed relationships provide sufficient information about the late-time radiation to yield a predictive model for the late-time waveforms, an alternative to the common practice of modeling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Spacelike gravitational radiation extraction from rotating binary black holes
Imbiriba, Breno C. O.
2016-07-01
We introduce an alternate method for gravitational radiation extraction for binary black hole mergers where we do not use a single extraction radius at the intermediate field region but instead use a whole spherical shell of three-dimensional (3D) data and continue its evolution using the linearized (Teukolsky) evolution to a final distant radiation extraction radius. We implement this using the Hahndol code for the 3D evolution, and use the “Lazarus” procedure to convert the numerical data into the linearized data. The final waveform is compatible with the ones obtained from the full 3D evolutions with some minor variations that require further study. In the process, we tested the “Lazarus” method with our numerical 3D implementation and gauges showing that even with the advanced gauges suitable for 3D rotating binary evolutions, we recover the same type of limited results obtained in the original work.
Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty
Energy Technology Data Exchange (ETDEWEB)
Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai
2013-03-01
The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.
High energy radiation effects on the human body
International Nuclear Information System (INIS)
High-energy radiation injuries and their risks were recognized, information on low-energy radiation injuries was also arranged, and with these backgrounds, countermeasures against prevention of radiation injuries were considered. Redintegration of DNA and mutation by radiation were described, and relationship between radiation injuries and dose was considered. Interaction of high-energy radiation and substances in the living body and injuries by the interaction were also considered. Expression method of risk was considered, and a concept of protection dose was suggested. Protection dose is dose equivalent which is worthy of value at the point where the ratio to permissible dose distributed among each part of the body is at its maximum in the distribution of dose equivalent formed within the body when standard human body is placed at a certain radiation field for a certain time. Significance and countermeasures of health examination which is under an abligation to make radiation workers receive health check were thought, and problems were proposed on compensation when radiation injuries should appear actually. (Tsunoda, M.)
Computing precession and spin-curvature coupling for small bodies orbiting Kerr black holes
Hughes, Scott; Ruangsri, Uchupol; Vigeland, Sarah
2016-03-01
A non-spinning small body that orbits a Kerr black hole follows a trajectory that looks like a geodesic corrected by ``self force'' effects that drive inspiral and shift the small body's orbital frequencies. If the small body is spinning, then additional forces arise from the coupling of its spin to the curvature of the larger black hole. In this talk, I will describe recent work to compute the precession of this small body in the frequency domain for generic orbit geometries and generic small body orientations, and show how this result can be used to compute the spin-curvature force in a computationally effective way.
Oscillations of radiation pressure supported tori near black holes
Mazur, Grzegorz P.; Zanotti, Olindo; Sądowski, Aleksander; Mishra, Bhupendra; Kluźniak, Wlodek
2016-03-01
We study the dynamics of radiation pressure supported tori around Schwarzschild black holes, focusing on their oscillatory response to an external perturbation. Using KORAL, a general relativistic radiation-hydrodynamics code capable of modelling all radiative regimes from the optically thick to the optically thin, we monitor a sample of models at different initial temperatures and opacities, evolving them in two spatial dimensions for ˜165 orbital periods. The dynamics of models with high opacity is very similar to that of purely hydrodynamics models, and it is characterized by regular oscillations which are visible also in the light curves. As the opacity is decreased, the tori quickly and violently migrate towards the gas-pressure dominated regime, collapsing towards the equatorial plane. When the spectra of the L2 norm of the mass density are considered, high-frequency inertial-acoustic modes of oscillations are detected (with the fundamental mode at a frequency 68 M_BH^{-1} Hz), in close analogy to the phenomenology of purely hydrodynamic models. An additional mode of oscillation, at a frequency 129 M_BH^{-1} Hz, is also found, which can be unambiguously attributed to the radiation. The spectra extracted from the light curves are typically noisier, indicating that in a real observation such modes may not be easily detected.
Directory of Open Access Journals (Sweden)
Rynal Devanathan
2013-01-01
Full Text Available Background: Excess weight contributes to the development and progression of Type 2 diabetes mellitus (T2DM. Distorted body image amongst urban Black women and the perception that thinness is linked with HIV, may however be compounding the problem, particularly in areas with a high HIV burden.Objectives: This study aimed to compare the perception of body image in urban Black women with and without T2DM.Methods: A cross-sectional comparative study was conducted on 328 Black women systematically sampled into two groups (with and without T2DM. Body mass index (BMI (weight [kg]/height[m2] was determined and the adapted Stunkard Body Image Silhouettes for Black women was used to determine perceived body image (PBI.Results: Seventy-two per cent had T2DM and in this group 89% were obese, with a mean BMI of 39.5 kg/m2 (s.d. ± 8.5. In the non-diabetes group (NDG 44% were obese, with a mean BMIof 31.3 kg/m2 (s.d. ± 9.0 Black women underestimated their body image across all weight categories (p < 0.05. Both groups (99% of the study group also perceived thinness as being associated with HIV.Conclusions: This study identified an incongruence between PBI and actual BMI amongst urban Black women. This, combined with their belief that thinness is associated with HIV, places those with T2DM at risk of secondary complications arising from diabetes mellitus, and those without diabetes mellitus at a higher risk of developing T2DM. A discrepancy between PBI and BMI may therefore serve as a risk marker to alert clinicians to use a more ethno-cultural specific approach in engaging with urban Black women regarding weight loss strategies in the future.
Characteristics of Quantum Radiation of Slowly Varying Nonstationary Kerr-Newman Black Holes
Hua, Jia-Chen; Huang, Yong-chang
2006-01-01
Quantum radiative characteristics of slowly varying nonstationary Kerr-Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation, which is that the chemical potential in thermal radiation spectrum is equal to ...
Ethnic Identity and Body Image among Black and White College Females
Baugh, Eboni; Mullis, Ron; Mullis, Ann; Hicks, Mary; Peterson, Gary
2010-01-01
Objective: This study examines ethnic identity and body image in black and white college females. Participants: Researchers surveyed 118 students at 2 universities, 1 traditionally white and 1 historically black. Methods: Correlations and multivariate analysis of variance (MANOVA) were used to investigate the relationship between race, ethnic…
Radiation between segments of the seated human body
DEFF Research Database (Denmark)
Sørensen, Dan Nørtoft
2002-01-01
Detailed radiation properties for a thermal manikin were predicted numerically. The view factors between individual body-segments and between the body-segments and the outer surfaces were tabulated. On an integral basis, the findings compared well to other studies and the results showed that situ...
Sri Rachma, Aprilita Bugiwati
2008-01-01
This experiment was done at 292 head of Japanese black bull at Kagoshima and Miyazaki Prefectural Experimental Stations Japan to find out the relationship between ultrasonic estimates of carcass traits and body measurements as one of criteria to select Japanese black bull. The carcass traits of 20 months of age were predicted using the ultrasonic machine. The body dimensions were measured at the end of performance test (12 months of age) and 16 months of age. The ultrasonic evaluati...
Hawking radiation of massive vector particles from the linear dilaton black holes
Li, Ran; Zhao, Junkun
2016-07-01
By using the tunneling formalism, we calculated the massive vector particles' Hawking radiation from the non-rotating and rotating linear dilaton black holes. By applying the WKB approximation to the Proca field equation that govern the dynamics of massive vector bosons, we derive the tunneling probabilities and radiation spectrums of the emitted vector particles from the linear dilaton black holes. The Hawking temperatures of the linear dilaton black holes have been recovered, which are consistent with the previous results in the literature. This means that the vector particles' tunneling method can also be used in studying the Hawking radiation of asymptotically non-flat and non-AdS black holes.
Radiation from collapsing shells, semiclassical backreaction, and black hole formation
International Nuclear Information System (INIS)
We provide a detailed analysis of quantum field theory around a collapsing shell and discuss several conceptual issues related to the emission of radiation flux and formation of black holes. Explicit calculations are performed using a model for a collapsing shell, which turns out to be analytically solvable. We use the insights gained in this model to draw reliable conclusions regarding more realistic models. We first show that any shell of mass M, which collapses to a radius close to r=2M, will emit approximately thermal radiation for a period of time. In particular, a shell that collapses from some initial radius to a final radius 2M(1-ε2)-1 (where ε2). Later on (t>>Mln(1/ε2)), the flux from such a shell will decay to zero exponentially. We next study the effect of backreaction computed using the vacuum expectation value of the stress tensor on the collapse. We find that, in any realistic collapse scenario, the backreaction effects do not prevent the formation of the event horizon. The time at which the event horizon is formed is, of course, delayed due to the radiated flux--which decreases the mass of the shell--but this effect is not sufficient to prevent horizon formation. We also clarify several conceptual issues and provide pedagogical details of the calculations in the Appendices to the paper.
NON-THERMAL RADIATION FROM A NON-KERR-NEWMAN BLACK HOLE
Institute of Scientific and Technical Information of China (English)
谢实崇; 杨雪特; 杨树政; 林理彬
2001-01-01
In the spacetime of a charged spinning black hole, the distribution of particle energy levels has been studied. Near the event horizon of such a black hole a crossing of the particle energy levels exists, which leads to the occurrence of non-thermal radiation of the black hole. This quantum effect is non-thermal and also different from those of the Kerr and Kerr-Newman black holes.
Black hole and Hawking radiation by type-II Weyl fermions
Volovik, G E
2016-01-01
The type-II Weyl and type-II Dirac fermions may emerge behind the event horizon of black holes. Correspondingly the black hole can be simulated by creation of the region with overtilted Weyl or Dirac cones. The filling of the electronic states inside the "black hole" is accompanied by Hawking radiation. The Hawking temperature in the Weyl semimetals can reach the room temperature, if the black hole region is sufficiently small, and thus the effective gravity at the horizon is large.
Hawking Radiation of Vector Particles via Tunneling From 4-Dimensional And 5-Dimensional Black Holes
Feng, Zhongwen; Zu, Xiaotao
2016-01-01
Using Proca equation and WKB approximation, we investigate Hawking radiation of vector particles via tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole. The results show that the tunneling rates and Hawking temperatures are depended on the properties of spacetime (event horizon, mass and angular momentum). Besides, our results are the same as scalars and fermions tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole.
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. Furthermore, all of the couplings can be "deduced" from those of a pole-dipole test body in Kerr.
Hawking Radiation of Linear Dilaton Black Holes in Various Theories
Pasaoglu, H
2009-01-01
Using the Damour-Ruffini-Sannan, the Parikh-Wilczek and the thin film brick-wall models, we investigate the Hawking radiation of uncharged massive particles from 4-dimensional linear dilaton black holes, which are the solutions to Einstein-Maxwell-Dilaton, Einstein-Yang-Mills-Dilaton and Einstein-Yang-Mills-Born-Infeld-Dilaton theories. Our results show that the tunneling rate is related to the change of Bekenstein-Hawking entropy. Contrary to the many studies in the literature, here the emission spectrum is precisely thermal. This implies that the derived emission spectrum is not consistent with the unitarity of the quantum theory, which would possibly lead to the information loss.
Hamilton-Jacobi Ansatz to Study the Hawking Radiation of Kerr-Newman Black Holes
Chen, Deyou; Yang, Shuzheng
Taking the self-gravitation interaction and unfixed background space-time into account, we study the Hawking radiation of Kerr-Newman-Kasuya black holes using Hamilton-Jacobi method. The result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiation spectrum deviates from the purely thermal one, which is accordant with that obtained using Parikh and Wilczek's method and gives a correction to the Hawking radiation of the black hole.
Corrected Hawking Radiation of Dirac Particles from a General Static Riemann Black Hole
Directory of Open Access Journals (Sweden)
Ge-Rui Chen
2013-01-01
Full Text Available Considering energy conservation and the back reaction of radiating particles to the spacetime, we investigate the massive Dirac particles' Hawking radiation from a general static Riemann black hole using improved Damour-Ruffini method. A direct consequence is that the radiation spectrum is not strictly thermal. The correction to the thermal spectrum is consistent with an underlying unitary quantum theory and this may have profound implications for the black hole information loss paradox.
Hawking radiation from a spherical loop quantum gravity black hole
International Nuclear Information System (INIS)
We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step toward studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space-time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back-reaction calculations in more traditional treatments. The discreteness of area leads to modifications of the quantum vacua, eliminating the trans-Planckian modes close to the horizon, which in turn eliminates all singularities from physical quantities, like the expectation value of the stress–energy tensor. Apart from this, the Boulware, Hartle–Hawking and Unruh vacua differ little from the treatment on a classical space-time. The asymptotic modes near scri are reproduced very well. We show that the Hawking radiation can be computed, leading to an expression similar to the conventional one but with a high frequency cutoff. Since many of the conclusions concern asymptotic behavior, where the spherical mode of the field behaves in a similar way as higher multipole modes do, the results can be readily generalized to non spherically symmetric fields. (paper)
Hawking radiation from a spherical loop quantum gravity black hole
Gambini, Rodolfo; Pullin, Jorge
2014-06-01
We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step toward studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space-time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back-reaction calculations in more traditional treatments. The discreteness of area leads to modifications of the quantum vacua, eliminating the trans-Planckian modes close to the horizon, which in turn eliminates all singularities from physical quantities, like the expectation value of the stress-energy tensor. Apart from this, the Boulware, Hartle-Hawking and Unruh vacua differ little from the treatment on a classical space-time. The asymptotic modes near scri are reproduced very well. We show that the Hawking radiation can be computed, leading to an expression similar to the conventional one but with a high frequency cutoff. Since many of the conclusions concern asymptotic behavior, where the spherical mode of the field behaves in a similar way as higher multipole modes do, the results can be readily generalized to non spherically symmetric fields.
Who's that Girl: Television's Role in the Body Image Development of Young White and Black Women
Schooler, Deborah; Ward, L. Monique; Merriwether, Ann; Caruthers, Allison
2004-01-01
Although findings indicate a connection between frequent media use and greater body dissatisfaction, little attention has focused on the role of race. Accordingly, this study investigates the relation between television viewing and body image among 87 Black and 584 White women. Participants reported monthly viewing amounts of mainstream and…
Quantum radiation of non-stationary Kerr-Newman-de Sitter black hole
Institute of Scientific and Technical Information of China (English)
Jiang Qing-Quan; Yang Shu-Zheng; Li Hui-Ling
2005-01-01
By introducing a new tortoise coordinate transformation, we investigate the quantum thermal and non-thermal radiations of a non-stationary Kerr-Newman-de Sitter black hole. The accurate location and radiate temperature of the event horizon as well as the maximum energy of the non-thermal radiation are derived. It is shown that the radiate temperature and the maximum energy are related to not only the evaporation rate, but also the shape of the event horizon, moreover the maximum energy depends on the electromagnetic potential. Finally, we use the results to reduce the non-stationary Kerr-Newman black hole, the non-stationary Kerr black hole, the stationary Kerr-Newman-de Sitter black hole, and the static Schwarzshild black hole.
Webb, Jennifer B.; Butler-Ajibade, Phoebe; Robinson, Seronda A.
2014-01-01
The present study provided an initial evaluation of an affect regulation model describing the association between body dissatisfaction and two contemporary measures of positive body image among 247 Black college-bound older adolescent females. We further tested whether possessing a higher body mass index (BMI) would strengthen these associations. Self-reported height and weight were used to calculate BMI. Respondents also completed a culturally-sensitive figure rating scale along with assessm...
Information-carrying Hawking radiation and the number of microstate for a black hole
Cai, Qing-yu; You, Li
2016-01-01
We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein-Hawking entropies for Schwarzschild black holes and Reissner-Nordstr\\"om black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner-Nordstr\\"om black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein-Hawking entropy of extremal black holes in the semiclassical limit.
Anesthesia and monitoring during whole body radiation in children
DEFF Research Database (Denmark)
Henneberg, S; Nilsson, A; Hök, B;
1991-01-01
During whole body radiation therapy of children, treatment may be done in places not equipped with acceptable scavenging systems for anesthetic gases and where clinical observation of the patient may be impossible. In order to solve this problem, the authors have used a total intravenous (IV) ane....... This anesthetic technique and the stethoscope have been used in seven children. The total IV anesthesia proved to be a useful method for children during whole body radiation. The modified stethoscope functioned very well and was a useful complement to the monitoring equipment....
Taste aversions conditioned with partial body radiation exposures
International Nuclear Information System (INIS)
Radiation-induced taste aversion was compared in rats which received partial body exposure to the head or abdomen with rats receiving whole body irradiation. Exposure levels ranged from 25 to 300 roentgens (R). In additional groups, saccharin aversion to partial body gamma ray exposures of the abdomen were conditioned in animals which had prior experience with the saccharin solution. Aversion was measured with a single-bottle short-term test, a 23-hour preference test and by the number of days taken to recover from the aversion. Whole-body exposure was most effective in conditioning the aversion, and exposure of the abdominal area was more effective than exposure to the head. Also, the higher the exposure, the stronger the aversion. Rats receiving prior experience with the saccharin did not condition as well as control rats with no prior saccharin experience. The possible role of radiation-induced taste aversion in human radiotherapy patients was discussed. (author)
Characteristics of Quantum Radiation of Slowly Varying Nonstationary Kerr-Newman Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiative characteristics of slowly varying nonstationary Kerr-Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in non-thermal radiation for slowly varying nonstationary Kerr-Newman black holes. Also, we show that the deduced general results can be degenerated to the known conclusion of stationary Kerr-Newman black holes.
Hawking radiation from z=3 and z=1-Lifshitz black holes
Lepe, Samuel
2014-01-01
The Hawking radiation considered as a tunneling process, by using a Hamilton-Jacobi prescription, is discussed for both z=3 and z=1-Lifshitz black holes. We have found that the tunneling rate (which is not thermal but related to the change of entropy) for the z=3-Lifshitz black hole (which does not satisfy the Area/4-law) does not yield (give us) the ecpected tunneling rate: $\\Gamma\\simeq exp(\\Delta S)$, where $\\Delta S$ is the change of black hole entropy, if we compare with the z=1-Lifshitz black hole (BTZ black hole, which satisfies the Area/4-law).
Hawking radiation from z = 3 and z = 1-Lifshitz black holes
Lepe, Samuel; Merello, Bruno
2014-10-01
The Hawking radiation considered as a tunneling process, by using a Hamilton-Jacobi prescription, is discussed for both z = 3 and z = 1-Lifshitz black holes. We have found that the tunneling rate (which is not thermal but related to the change of entropy) for the z = 3-Lifshitz black hole (which does not satisfy the Area/4-law) does not yield (give us) the expected tunneling rate: Γ exp(ΔS), where ΔS is the change of black hole entropy, if we compare with the z = 1-Lifshitz black hole (BTZ black hole, which satisfies the Area/4-law).
Correction to Hawking Radiation Characteristics of Stationary Demianski-Newman Black Hole
Institute of Scientific and Technical Information of China (English)
JIANG Qing-Quan; YANG Shu-Zheng
2006-01-01
The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneling rate of the particle is relevant to Bekenstein-Hawking entropy, and the derived radiate spectrum is not strictly pure thermal,but is consistent with underlying unitary theory. Finally, we use the obtained results to reduce to stationary Kerr black hole and static Schwarzschild black hole, and find that only when ignoring the spectrum at higher energies is the tunneling radiation spectrum consistent with Hawking pure thermal one.
Quantum tunneling radiation from self-dual black holes
Energy Technology Data Exchange (ETDEWEB)
Silva, C.A.S., E-mail: calex@fisica.ufc.br [Instituto Federal de Educação Ciência e Tecnologia da Paraíba (IFPB), Campus Campina Grande, Rua Tranquilino Coelho Lemos, 671, Jardim Dinamérica I (Brazil); Brito, F.A., E-mail: fabrito@df.ufcg.edu.br [Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba (Brazil)
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton–Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Quantum tunneling radiation from self-dual black holes
Silva, C. A. S.; Brito, F. A.
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton-Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin; Steinhoff, Jan
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. ...
Protection Strategy of Sensitive Body Organs in Radiation Therapy
Abolfath, Ramin M
2009-01-01
In this paper, we investigate protection strategies of sensitive body anatomy against the irradiation to the cancerous moving tumors in intensity modulated radiation therapy. Inspired by optimization techniques developed in statistical physics and dynamical systems, we deploy a method based on variational principles and formulate an efficient genetic algorithm which enable us to search for global minima in a complex landscape of irradiation dose delivered to the radiosensitive organs at risk. We take advantage of the internal motion of body anatomy during radiation therapy to reduce the unintentional delivery of the radiation to sensitive organs. We show that the accurate optimization of the control parameters, compare to the conventional IMRT and widely used delivery based on static anatomy assumption, leads to a significant reduction of the dose delivered to the organs at risk.
Hawking Radiation Energy and Entropy from a Bianchi-Smerlak Semiclassical Black Hole
Abdolrahimi, Shohreh
2015-01-01
Eugenio Bianchi and Matteo Smerlak have found a relationship between the Hawking radiation energy and von Neumann entropy in a conformal field emitted by a semiclassical two-dimensional black hole. We compare this relationship with what might be expected for unitary evolution of a quantum black hole in four and higher dimensions. If one neglects the expected increase in the radiation entropy over the decrease in the black hole Bekenstein-Hawking A/4 entropy that arises from the scattering of the radiation by the barrier near the black hole, the relation works very well, except near the peak of the radiation von Neumann entropy and near the final evaporation. These discrepancies are calculated and discussed as tiny differences between a semiclassical treatment and a quantum gravity treatment.
Hawking radiation of scalar particles from accelerating and rotating black holes
Energy Technology Data Exchange (ETDEWEB)
Gillani, Usman A.; Rehman, Mudassar; Saifullah, K., E-mail: mani_precious2001@yahoo.com, E-mail: mudassar051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-06-01
Hawking radiation of uncharged and charged scalar particles from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using this method we recover the correct Hawking temperature as well.
Cuesta-Martínez, Carlos F; Mimica, Petar
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated GRBs, namely long lasting events characterized by the presence of a notable thermal component trailing the GRB prompt emission, and a rather weak traditional afterglow. GRB 101225A, the Christmas Burst (CB), is a prototype of such class. It has been suggested that BBD-GRBs could result from the merger of a binary system formed by a neutron star and the Helium core of a main sequence star. We have modeled the propagation of ultrarelativistic jets through the environment left behind the merger by means of detailed relativistic hydrodynamic numerical simulations. In this paper, the output of our numerical models is further postprocessed to obtain the (thermal) radiative signature of the resulting outflow. The complete (thermal and non-thermal) output of our models is considered in a companion contribution. Here, we outline the most relevant dynamical details of the jet propagation and connect them to the generation of thermal ra...
Black Pete, "smug ignorance," and the value of the black body in postcolonial Netherlands
Van Der Pijl, Yvon; Goulordava, Karina
2014-01-01
This article discusses the controversies over the blackface figure Black Pete (Zwarte Piet)-central to the popular Dutch Saint Nicholas holiday tradition-and the public uproar surrounding the Saint Nicholas feast in 2013. It combines history, social theory, and patchwork ethnography, and draws on th
$W_\\infty$ Algebras, Hawking Radiation and Information Retention by Stringy Black Holes
Ellis, John; Nanopoulos, Dimitri V
2016-01-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (whose singular regions are represented by appropriate Wess-Zumino-Witten models) is retained by quantum $W$-symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole requires a contribution from $W_\\infty$ generators in its vertex function. The latter correspond to delocalised, non-propagating, string excitations that guarantee the transfer of information between the string black hole and external particles. When infalling matter crosses the horizon, these topological states are excited via a process: (Stringy black hole) + infalling matter $\\rightarrow $ (Stringy black hole)$^\\star$, where the black hole is viewed as a stringy state with a specific configuration of $W_\\infty$ charges...
Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole
Wu, S Q
2002-01-01
Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect is absent from the thermal radiation spectrum of scalar particles.
Yuan, Ye-Fei; Cao, Xinwu; Huang, Lei; Shen, Zhi-Qiang
2009-01-01
In fully general relativity, we calculate the images of the radiatively inefficient accretion flow (RIAF) surrounding a Kerr black hole with arbitrary spins, inclination angles, and observational wavelengths. For the same initial conditions, such as the fixed accretion rate, it is found that the intrinsic size and radiation intensity of the images become larger, but the images become more compact in the inner region, while the size of the black hole shadow decreases with the increase of the b...
Hawking radiation of asymptotically non-flat dyonic black holes in Einstein-Maxwell-dilaton gravity
Slavov, Peter I.; Yazadjiev, Stoytcho S.
2012-01-01
In the present paper we investigate the Hawking radiation of asymptotically non-flat dyonic black holes in 4D Einstein-Maxwell-dilaton gravity in semi-classical approximation. We show that the problem allows an exact analytical treatment and we compute exactly the semi-classical radiation spectrum of both non-extremal and extremal black holes under consideration. In the high frequency regime we find that the Hawking temperature does not agree with the surface gravity when the magnetic charge ...
General Relativistic Radiative Transfer Code in Rotating Black Hole Spacetime: {ARTIST}
Takahashi, Rohta; Umemura, Masayuki
2016-10-01
We present a general relativistic radiative transfer code, {ARTIST} (Authentic Radiative Transfer In Space-Time), which is a perfectly causal scheme to pursue the propagation of radiation with absorption and scattering around a Kerr black hole. The code explicitly solves the invariant radiation intensity along null geodesics in the Kerr-Schild coordinates, and therefore properly includes light bending, Doppler boosting, frame dragging, and gravitational redshifts. The notable aspect of {ARTIST} is that it conserves the radiative energy with high accuracy, and is not subject to the numerical diffusion, since the transfer is solved on long characteristics along null geodesics. We first solve the wavefront propagation around a Kerr black hole, which was originally explored by Hanni (1977). This demonstrates repeated wavefront collisions, light bending, and causal propagation of radiation with the speed of light. We show that the decay rate of the total energy of wavefronts near a black hole is determined solely by the black hole spin in late phases, in agreement with analytic expectations. As a result, the {ARTIST} turns out to correctly solve the general relativistic radiation fields until late phases as t ˜ 90M. We also explore the effects of absorption and scattering, and apply this code for a photon wall problem and an orbiting hot spot problem. All the simulations in the present study are performed in the equatorial plane around a Kerr black hole. The {ARTIST} is the first step to realize the general relativistic radiation hydrodynamics.
International Nuclear Information System (INIS)
The existence of the Hawking radiation of the black hole surely affected the space-time. In this paper, using the result which is obtained by the thermodynamics method and applying the semiclassical Einstein equation when the radiation field is existent, it was obtained the static spherically symmetric metric of a Schwarzschild black hole (SBH) surrounded by the radiation field. Using this metric, it was found that the relation between the radiation energy density and the radius pressure is in accordance with the relation of the space-time
Quantum Geometry and Thermal Radiation from Black Holes
Krasnov, Kirill
1997-01-01
A quantum mechanical description of black hole states proposed recently within non-perturbative quantum gravity is used to study the emission and absorption spectra of quantum black holes. We assume that the probability distribution of states of the quantum black hole is given by the ``area'' canonical ensemble, in which the horizon area is used instead of energy, and use Fermi's golden rule to find the line intensities. For a non-rotating black hole, we study the absorption and emission of s...
Radiation doses from contaminant aerosol deposition to the human body
International Nuclear Information System (INIS)
Nearly all assessments of radiation doses received following accidental airborne releases have focused on the contributions originating from the plume and from ground deposition. Very little thought has however been given to doses received from deposition directly onto humans. The results of recent experimental investigations of aerosol deposition to and clearance from human skin and clothing have been used to model the doses potentially received in an accident situation. It was found that both the skin dose from β-emitters and the whole body dose from γ-emitters may be significant compared with doses received through other pathways, such as external radiation from the environment. (au)
Accurate Waveforms for Non-spinning Binary Black Holes using the Effective-one-body Approach
Buonanno, Alessandra; Pan, Yi; Baker, John G.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; vanMeter, James R.
2007-01-01
Using numerical relativity as guidance and the natural flexibility of the effective-one-body (EOB) model, we extend the latter so that it can successfully match the numerical relativity waveforms of non-spinning binary black holes during the last stages of inspiral, merger and ringdown. Here, by successfully, we mean with phase differences black-hole masses. The final black-hole mass and spin predicted by the numerical simulations are used to determine the ringdown frequency and decay time of three quasi-normal-mode damped sinusoids that are attached to the EOB inspiral-(plunge) waveform at the light-ring. The accurate EOB waveforms may be employed for coherent searches of gravitational waves emitted by non-spinning coalescing binary black holes with ground-based laser-interferometer detectors.
Hawking Radiation of a Kaluza-Klein Black Hole Described by Landauer Transport Model
Institute of Scientific and Technical Information of China (English)
兰小刚; 韦联福
2012-01-01
We investigate the Hawking radiation of a Kaluza-Klein black hole by using one-dimensional(1D),non-equilibrium,Landauer transport model.The derived Hawking radiation temperature is in consistence with that obtained by using the usual anomaly method.With the Landauer transport model,we calculate the entropy flow out of the Kaluza-Klein black hole and the relevant entropy production rate.How these quantities depending on the physical parameters of the black hole is also discussed.
Low-energy electromagnetic radiation as an indirect probe of black-hole evaporation
Emelyanov, Slava
2016-01-01
We study the influence of black-hole evaporation on light propagation. The framework employed is based on the non-linear QED effective action at one-loop level. We show that the light-cone condition is modified for low-energy radiation due to black-hole evaporation. We discuss conditions under which the phase velocity of this low-energy radiation is greater than $c$. We also compute the modified light-deflection angle, which turns out to be significantly different from the standard GR value for black-hole masses in the range $M_\\text{Pl} \\ll M \\lesssim 10^{19}\\;M_\\text{Pl}$.
Scattering coefficients and gray-body factor for 1D BEC acoustic black holes: exact results
Fabbri, Alessandro; Anderson, Paul R
2015-01-01
A complete set of exact analytic solutions to the mode equation are found in the region exterior to the acoustic horizon for a class of 1D Bose-Einstein condensate (BEC) acoustic black holes. From these, analytic expressions for the scattering coefficients and gray-body factor are obtained. The results are used to verify previous predictions regarding the behaviors of the scattering coefficients and gray-body factor in the low frequency limit.
Black hole radiation spectrum in loop quantum gravity: isolated horizon framework
Energy Technology Data Exchange (ETDEWEB)
Diaz-Polo, Jacobo [Departamento de Astronomia y Astrofisica, Universidad de Valencia, Burjassot-46100, Valencia (Spain); Fernandez-Borja, Enrique [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC. Universidad de Valencia, Burjassot-46100, Valencia (Spain)], E-mail: Jacobo.Diaz@uv.es, E-mail: Enrique.Fernandez@uv.es
2008-05-21
Recent detailed analysis within the loop quantum gravity calculation of black hole entropy shows a stair-like structure in the behavior of entropy as a function of horizon area. The non-trivial distribution of the degeneracy of the black hole horizon area eigenstates is at the origin of this behavior. This degeneracy distribution is analyzed and a phenomenological model is put forward to study the implications of this distribution in the black hole radiation spectrum. Some qualitative quantum effects are obtained within the isolated horizon framework. This result provides us with a possible observational test of this model for quantum black holes.
International Nuclear Information System (INIS)
The radiation protection standard recommended by ICRP was evaluated in terms of its suitability for Chinese people. The body height and weight of 100,325 healthy Chinese were measured and anatomical data collected from usable corpses of persons who died by accident or sudden death. The data included the size and weight of certain organs. 18 refs
W∞ algebras, Hawking radiation, and information retention by stringy black holes
Ellis, John; Mavromatos, Nick E.; Nanopoulos, D. V.
2016-07-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (the singular regions of which are represented by appropriate Wess-Zumino-Witten models) is retained by quantum W symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole requires a contribution from W∞ generators in its vertex function. The latter correspond to delocalized, nonpropagating, string excitations that guarantee the transfer of information between the string black hole and external particles. When infalling matter crosses the horizon, these topological states are excited via a process: (stringy black hole) + infalling matter → (stringy black hole)⋆ , where the black hole is viewed as a stringy state with a specific configuration of W∞ charges that are conserved. Hawking radiation is then the reverse process, with conservation of the W∞ charges retaining information. The Hawking radiation spectrum near the horizon of a Schwarzschild or Kerr black hole is specified by matrix elements of higher-order currents that form a phase-space W1 +∞ algebra. We show that an appropriate gauging of this algebra preserves the horizon two-dimensional area classically, as expected because the latter is a conserved Noether charge.
The Mirror of Television: A Comparison of Black and White Adolescents' Body Image.
Botta, Renee A.
2000-01-01
Finds that black adolescent girls were more satisfied with their bodies and had a larger personal ideal size than white adolescent girls, but engaged in no fewer eating-disordered behaviors and had no less drive to be thin; and these girls idealized television images equally and were as likely to compare themselves and their friends to television…
Hawking Radiation from Elko Particles Tunnelling across Black Strings Horizon
da Rocha, Roldao
2014-01-01
We apply the tunnelling method for the emission and absorption of Elko particles in the event horizon of a black string solution. We show that Elko particles are emitted at the expected Hawking temperature from black strings, but with a quite different signature with respect to the Dirac particles. We employ the Hamilton-Jacobi technique to black hole tunnelling, by applying the WKB approximation to the coupled system of Dirac-like equations governing the Elko particle dynamics. As a typical signature, different Elko particles are shown to produce the same standard Hawking temperature for black strings. However we prove that they present the same probability irrespective of outgoing or ingoing the black hole horizon. It provides a typical signature for mass dimension one fermions, that is different from the mass dimension three halves fermions inherent to Dirac particles, as different Dirac spinor fields have distinct inward and outward probability of tunnelling.
Hawking radiation of Reissner-Nordstrom-de Sitter black hole by Hamilton-Jacobi method
Hossain, M Ilias
2013-01-01
In Refs. (M. Atiqur Rahman, M. Ilias Hossain (2012) Phys. Lett. B {\\bf 712} 1), we have developed Hamilton-Jacobi method for dynamical spacetime and discussed Hawking radiation of Schwarzschild-de Sitter black hole by massive particle tunneling method. In this letter, we have investigated the hawking purely thermal and nonthermal radiations of Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole. We have considered energy and angular momentum as conserved and shown that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results we have obtained for RNdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and recovered the new result for Hawking radiation of RNdS black hole.
She Had a Name That God Didn’t Give Her: Thinking the Body through Atheistic Black Radical Feminism
Marquis Bey
2015-01-01
The article attempts to demonstrate the necessity of acknowledging the body when considering the current Black Lives Matter movement, give an account of Black female and trans erasure, and ultimately (re)affirm the lived embodiment of Black, female, and trans bodies, all through an atheistic lens. Atheism here, while indeed denying the existence of gods, has as its primary concern affirming life. Too often is theology, as theologian Anthony Pinn says, “a theology of no-body”; thus atheistic f...
Gastrointestinal Toxicities With Combined Antiangiogenic and Stereotactic Body Radiation Therapy
Energy Technology Data Exchange (ETDEWEB)
Pollom, Erqi L.; Deng, Lei [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Pai, Reetesh K. [Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States); Brown, J. Martin; Giaccia, Amato; Loo, Billy W.; Shultz, David B.; Le, Quynh Thu; Koong, Albert C. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Chang, Daniel T., E-mail: dtchang@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States)
2015-07-01
Combining the latest targeted biologic agents with the most advanced radiation technologies has been an exciting development in the treatment of cancer patients. Stereotactic body radiation therapy (SBRT) is an ablative radiation approach that has become established for the treatment of a variety of malignancies, and it has been increasingly used in combination with biologic agents, including those targeting angiogenesis-specific pathways. Multiple reports have emerged describing unanticipated toxicities arising from the combination of SBRT and angiogenesis-targeting agents, particularly of late luminal gastrointestinal toxicities. In this review, we summarize the literature describing these toxicities, explore the biological mechanism of action of toxicity with the combined use of antiangiogenic therapies, and discuss areas of future research, so that this combination of treatment modalities can continue to be used in broader clinical contexts.
Cosmological $N$-body simulations including radiation perturbations
Brandbyge, Jacob; Tram, Thomas; Leclercq, Florent; Fidler, Christian; Hannestad, Steen
2016-01-01
Cosmological $N$-body simulations are the standard tool to study the emergence of the observed large-scale structure of the Universe. Such simulations usually solve for the gravitational dynamics of matter within the Newtonian approximation, thus discarding general relativistic effects such as the coupling between matter and radiation ($\\equiv$ photons and neutrinos). In this paper we investigate novel hybrid simulations which incorporate interactions between radiation and matter to the leading order in General Relativity, whilst evolving the matter dynamics in full non-linearity according to Newtonian theory. Our hybrid simulations come with a relativistic space-time and make it possible to investigate structure formation in a unified framework. In the present work we focus on simulations initialized at $z=99$, and show that the extracted matter power spectrum receives up to $3\\%$ corrections on very large scales through radiation. Our numerical findings compare favourably with linear analytical results from...
Quantum Tunnelling for Hawking Radiation from Both Static and Dynamic Black Holes
Directory of Open Access Journals (Sweden)
Subenoy Chakraborty
2014-01-01
Full Text Available The paper deals with Hawking radiation from both a general static black hole and a nonstatic spherically symmetric black hole. In case of static black hole, tunnelling of nonzero mass particles is considered and due to complicated calculations, quantum corrections are calculated only up to the first order. The results are compared with those for massless particles near the horizon. On the other hand, for dynamical black hole, quantum corrections are incorporated using the Hamilton-Jacobi method beyond semiclassical approximation. It is found that different order correction terms satisfy identical differential equation and are solved by a typical technique. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature.
Quantum Tunnelling for Hawking Radiation from Both Static and Dynamic Black Holes
International Nuclear Information System (INIS)
The paper deals with Hawking radiation from both a general static black hole and a nonstatic spherically symmetric black hole. In case of static black hole, tunnelling of nonzero mass particles is considered and due to complicated calculations, quantum corrections are calculated only up to the first order. The results are compared with those for massless particles near the horizon. On the other hand, for dynamical black hole, quantum corrections are incorporated using the Hamilton-Jacobi method beyond semiclassical approximation. It is found that different order correction terms satisfy identical differential equation and are solved by a typical technique. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature
Toward faithful templates for non-spinning binary black holes using the effective-one-body approach
Buonanno, Alessandra; Baker, John G; Centrella, Joan; Kelly, Bernard J; McWilliams, Sean T; van Meter, James R
2007-01-01
We present an accurate approximation of the full gravitational radiation waveforms generated in the merger of non-eccentric systems of two non-spinning black holes. Utilizing information from recent numerical relativity simulations and the natural flexibility of the effective-one-body (EOB) model, we extend the latter so that it can successfully match the numerical relativity waveforms during the last stages of inspiral, merger and ringdown. By ``successfully'' here, we mean with phase differences < 8% of a gravitational-wave cycle accumulated by the end of the ringdown phase, maximizing only over time of arrival and initial phase. We obtain this result by simply adding a 4-post-Newtonian order correction in the EOB radial potential and determining the (constant) coefficient by imposing high-matching performances with numerical waveforms of mass ratios m1/m2 = 1, 3/2, 2 and 4, m1 and m2 being the individual black-hole masses. The final black-hole mass and spin predicted by the numerical simulations are use...
Radiation spectrum of rotating Gdel black hole and correction entropy
Institute of Scientific and Technical Information of China (English)
张丽春; 林海; 李怀繁; 赵仁
2011-01-01
We study the Hawking radiation of the scalar field in the rotating Gdel black hole in minimal five-dimensional supergravity. We not only derive radiation spectra that satisfy the unitary principle but also obtain the correction term of Bekenstein-Hawking
a Method to Study the Hawking Radiation of the Kerr Black Hole
Chen, Deyou; Yang, Shuzheng
Using the Hamilton-Jacobi method, we discuss the Hawking radiation of the Kerr black hole. The result shows when the self-gravitational interaction as well as the conservation of energy and angular momentum are taken into account, the radiation spectrum deviates from the purely thermal one and the tunneling probability is related to the change of Bekenstein-Hawking entropy, which is in accordance with Parikh and Wilczek's result and gives a method to study the Hawking radiation of the black hole.
Observation of quantum Hawking radiation and its entanglement in an analogue black hole
Steinhauer, Jeff
2016-10-01
We observe spontaneous Hawking radiation, stimulated by quantum vacuum fluctuations, emanating from an analogue black hole in an atomic Bose-Einstein condensate. Correlations are observed between the Hawking particles outside the black hole and the partner particles inside. These correlations indicate an approximately thermal distribution of Hawking radiation. We find that the high-energy pairs are entangled, while the low-energy pairs are not, within the reasonable assumption that excitations with different frequencies are not correlated. The entanglement verifies the quantum nature of the Hawking radiation. The results are consistent with a driven oscillation experiment and a numerical simulation.
International Nuclear Information System (INIS)
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra, and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss the possible connections between these results and black-hole-black-hole collisions at the speed of light. Our results show that during the high-speed collision of a nonrotating hole with a rotating one, at most 35% of the total energy can get converted into gravitational waves. This 35% efficiency occurs only in the most optimistic situation, that of a zero impact parameter collision, along the equatorial plane, with an almost extreme Kerr black hole. In the general situation, the total gravitational energy radiated is expected to be much less, especially if the impact parameter increases. Thus, if one is able to produce black holes at the CERN Large Hadron Collider, at most 35% of the partons' energy should be emitted during the so-called balding phase. This energy will be missing, since we do not have gravitational wave detectors able to measure such amplitudes. The collision at the speed of light between one rotating black hole and a nonrotating one or two rotating black holes turns out to be the most efficient gravitational wave generator in the Universe
Energetic Gamma Radiation from Rapidly Rotating Black Holes
Hirotani, Kouichi
2015-01-01
Supermassive black holes are believed to be the central power house of active galactic nuclei. Applying the pulsar outer-magnetospheric particle accelerator theory to black-hole magnetospheres, we demonstrate that an electric field is exerted along the magnetic field lines near the event horizon of a rotating black hole. In this particle accelerator (or a gap), electrons and positrons are created by photon-photon collisions and accelerated in the opposite directions by this electric field, efficiently emitting gamma-rays via curvature and inverse-Compton processes. It is shown that a gap arises around the null charge surface formed by the frame-dragging effect, provided that there is no current injection across the gap boundaries. The gap is dissipating a part of the hole's rotational energy, and the resultant gamma-ray luminosity increases with decreasing plasma accretion from the surroundings. Considering an extremely rotating supermassive black hole, we show that such a gap reproduces the significant very-...
Radiation of Charged Black Holes and Modified Dispersion Relation
Kamali, A D
2016-01-01
We investigate the effects of a modified dispersion relation proposed by Majhi and Vagenas on the Reissner-Nordstr\\"{o}m black hole thermodynamics in a universe with large extra dimensions. It is shown that entropy, temperature and heat capacity receive new corrections and charged black holes in this framework have less degrees of freedom and decay faster compared to black holes in the Hawking picture. We also study the emission rate of black hole and compare our results with other quantum gravity approaches. In this regard, the existence of the logarithmic prefactor and the relation between dimensions and charge are discussed. This procedure is not only valid for a single horizon spacetime but it is also valid for the spacetimes with inner and outer horizons.
Gender and race matter: the importance of considering intersections in Black women's body image.
Capodilupo, Christina M; Kim, Suah
2014-01-01
Traditionally, body image literature has used race as a variable to explain ethnic-specific differences in body satisfaction and the prevalence of eating disorders. Instead of employing race as an explanatory variable, the present study utilized a qualitative method to explore the relationships among race, ethnicity, culture, discrimination, and body image for African American and Black women. The purpose of the study was to gain a deeper understanding of how race and gender interface with and inform body image. Women were recruited through community centers in a major metropolitan city and represented a diversity of ethnicities. In total, 26 women who identified racially as Black (mean age = 26 years) participated in 6 focus groups, which explored body ideals, societal messages, cultural values, racism, and sexism. Narrative data from the focus groups were analyzed using grounded theory. The central category, Body/Self Image, was informed by perceptions of and feelings about not only weight and shape but also hair, skin, and attitude. Three additional categories, each with multiple properties, emerged: Interpersonal Influences, Experiences of Oppression, and Media Messages. These categories interact to explain the central category of Body/Self Image, and an emergent theory is presented. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
Gender and race matter: the importance of considering intersections in Black women's body image.
Capodilupo, Christina M; Kim, Suah
2014-01-01
Traditionally, body image literature has used race as a variable to explain ethnic-specific differences in body satisfaction and the prevalence of eating disorders. Instead of employing race as an explanatory variable, the present study utilized a qualitative method to explore the relationships among race, ethnicity, culture, discrimination, and body image for African American and Black women. The purpose of the study was to gain a deeper understanding of how race and gender interface with and inform body image. Women were recruited through community centers in a major metropolitan city and represented a diversity of ethnicities. In total, 26 women who identified racially as Black (mean age = 26 years) participated in 6 focus groups, which explored body ideals, societal messages, cultural values, racism, and sexism. Narrative data from the focus groups were analyzed using grounded theory. The central category, Body/Self Image, was informed by perceptions of and feelings about not only weight and shape but also hair, skin, and attitude. Three additional categories, each with multiple properties, emerged: Interpersonal Influences, Experiences of Oppression, and Media Messages. These categories interact to explain the central category of Body/Self Image, and an emergent theory is presented. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24188651
Asymmetry of Hawking Radiation of Dirac Particles in a Charged Vaidya - de Sitter Black Hole
Wu, S Q
2001-01-01
The Hawking radiation of Dirac particles in a charged Vaidya - de Sitter black hole is investigated by using the method of generalized tortoise coordinate transformation. It is shown that the Hawking radiation of Dirac particles does not exist for $P_1, Q_2$ components, but for $P_2, Q_1$ components it does. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles.
Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)
International Nuclear Information System (INIS)
If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this Letter we revisit some phenomenological signatures of black hole production in TeV-gravity theories. We show that the bulk-to-brane ratio of black hole energy loss during the Hawking evaporation phase depends crucially on the black hole greybody factors and on the particle degrees of freedom. Since the greybody factors have not yet been calculated in the literature, and the particle content at trans-Planckian energies is not known, it is premature to claim that the black hole emits mainly on the brane. We also revisit the decay time and the multiplicity of the decay products of black hole evaporation. We give general formulae for black hole decay time and multiplicity. We find that the number of particles produced during the evaporation phase may be significantly lower than the average multiplicity which has been used in the past literature
She Had a Name That God Didn’t Give Her: Thinking the Body through Atheistic Black Radical Feminism
Directory of Open Access Journals (Sweden)
Marquis Bey
2015-11-01
Full Text Available The article attempts to demonstrate the necessity of acknowledging the body when considering the current Black Lives Matter movement, give an account of Black female and trans erasure, and ultimately (reaffirm the lived embodiment of Black, female, and trans bodies, all through an atheistic lens. Atheism here, while indeed denying the existence of gods, has as its primary concern affirming life. Too often is theology, as theologian Anthony Pinn says, “a theology of no-body”; thus atheistic feminist Blackness, as understood here, seeks to entrench the body rather than abstract it. Atheistic feminist Blackness reinscribes and affirms the subjectivity and humanity of Black, female, and trans bodies, countering hegemonic discourse that explicitly and implicitly states otherwise. The article’s emphasis of an atheistic posture stems from the prescient words of Catherine Keller: “atheist or agnostic feminists ignore the God-word at their own peril.” Therefore, the Black feminist ideological argument takes the “God-word” seriously, reckons with it, and offers an alternative to a theological tradition that often imbues the body with inherent flaw (sin, abstraction (soul, and erasure of the ontological value of Black, female, and noncisgendered bodies.
Higgins, M K; Lin, Stacy L; Alvarez, Alexandra; Bardone-Cone, Anna M
2015-06-01
Impulsivity has been linked to bulimic symptomatology in a number of studies; however, few have examined this relationship among Black women. We investigated the correlations between impulsivity and bulimic symptoms, and tested impulsivity as a moderator of the body shame/bulimic symptoms relationship among a sample of female undergraduates (N=276; 97 Blacks, 179 Whites). These participants provided data on body shame, impulsivity, and bulimic symptoms (EDE-Q binge eating frequency, BULIT-R, EDI-Bulimia). Among Blacks, impulsivity was significantly positively associated with all bulimic symptoms measures; among Whites, impulsivity was only positively correlated with binge eating frequency. Furthermore, among Blacks, the combination of high body shame and high impulsivity was associated with the highest levels of bulimic symptoms; these findings were not observed among Whites. This study highlights the importance of impulsivity and body shame in identifying bulimic symptomatology among Black women. PMID:25867526
N-Body Growth of a Bahcall-Wolf Cusp Around a Black Hole
Preto, M; Spurzem, R; Preto, Miguel; Merritt, David; Spurzem, Rainer
2004-01-01
We present a clear N-body realization of the growth of a Bahcall-Wolf f ~ E^0.25 (rho ~ 1/r^1.75) density cusp around a massive object ("black hole") at the center of a stellar system. Our N-body algorithm incorporates a novel implementation of Mikkola-Aarseth chain regularization to handle close interactions between star and black hole particles. Forces outside the chain were integrated on a GRAPE-6A/8 special-purpose computer with particle numbers up to N=0.25 x 10^6. We compare our N-body results with predictions of the isotropic Fokker-Planck equation and verify that the time dependence of the density (both configuration and phase-space) predicted by the Fokker-Planck equation is well reproduced by the N-body algorithm, for various choices of N and of the black hole mass. Our results demonstrate the feasibility of direct-force integration techniques for simulating the evolution of galactic nuclei on relaxation time scales.
On neutral scalar radiation by a massive orbiting star in extremal Kerr-Newman black hole
Energy Technology Data Exchange (ETDEWEB)
Xu, Xiao-Bao; Bai, Nan; Gao, Yi-Hong [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing (China)
2015-06-15
We extend the work of 1401.3746 about gravitational waves by a massive orbiting star in an extremal Kerr black hole to an extremal Kerr-Newman black hole for the scalar radiation, and we still find that it has a CFT interpretation from Kerr-Newman/CFT, because our scalar is neutral although the black hole is a charged one. When the charge of black hole is zero, we can get the result of 1401.3746, so we give a new evidence on Kerr-Newman/CFT. In addition, we investigate on electromagnetic radiation with Kerr/CFT in detail which isn't given by 1401.3746. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Information-carrying Hawking radiation and the number of microstate for a black hole
Directory of Open Access Journals (Sweden)
Qing-yu Cai
2016-04-01
Full Text Available We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein–Hawking entropy of extremal black holes in the semiclassical limit.
On neutral scalar radiation by a massive orbiting star in extremal Kerr-Newman black hole
International Nuclear Information System (INIS)
We extend the work of 1401.3746 about gravitational waves by a massive orbiting star in an extremal Kerr black hole to an extremal Kerr-Newman black hole for the scalar radiation, and we still find that it has a CFT interpretation from Kerr-Newman/CFT, because our scalar is neutral although the black hole is a charged one. When the charge of black hole is zero, we can get the result of 1401.3746, so we give a new evidence on Kerr-Newman/CFT. In addition, we investigate on electromagnetic radiation with Kerr/CFT in detail which isn't given by 1401.3746. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Growth of Accreting Supermassive Black Hole Seeds and Neutrino Radiation
Directory of Open Access Journals (Sweden)
Gagik Ter-Kazarian
2015-01-01
Full Text Available In the framework of microscopic theory of black hole (MTBH, which explores the most important processes of rearrangement of vacuum state and spontaneous breaking of gravitation gauge symmetry at huge energies, we have undertaken a large series of numerical simulations with the goal to trace an evolution of the mass assembly history of 377 plausible accreting supermassive black hole seeds in active galactic nuclei (AGNs to the present time and examine the observable signatures today. Given the redshifts, masses, and luminosities of these black holes at present time collected from the literature, we compute the initial redshifts and masses of the corresponding seed black holes. For the present masses MBH/M⊙≃1.1×106 to 1.3×1010 of 377 black holes, the computed intermediate seed masses are ranging from MBHSeed/M⊙≃26.4 to 2.9×105. We also compute the fluxes of ultrahigh energy (UHE neutrinos produced via simple or modified URCA processes in superdense protomatter nuclei. The AGNs are favored as promising pure UHE neutrino sources, because the computed neutrino fluxes are highly beamed along the plane of accretion disk, peaked at high energies, and collimated in smaller opening angle (θ≪1.
Radiative human body cooling by nanoporous polyethylene textile
Hsu, Po-Chun; Song, Alex Y.; Catrysse, Peter B.; Liu, Chong; Peng, Yucan; Xie, Jin; Fan, Shanhui; Cui, Yi
2016-09-01
Thermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving. We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers). We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton. Our processed nanoPE is an effective and scalable textile for personal thermal management.
Sakalli, I.
2016-01-01
Hawking radiation of charged massive spin-0 particles are studied in the gravitational, electromagnetic, dilaton, and axion fields of rotating linear dilaton black holes. In this geometry, we separate the covariant Klein--Gordon equation into radial and angular parts and obtain the exact solutions of both the equations in terms of the confluent Heun functions. Using the radial solution, we analyze the behavior of the wave solutions near the event horizon of the rotating linear dilaton black h...
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
Sakalli, I.; Ovgun, A.
2015-09-01
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton-Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.
General radiation via tunneling in Kerr and Kerr-Newman black holes
Institute of Scientific and Technical Information of China (English)
2008-01-01
Hawking radiation can be viewed as a process of quantum tunneling near the black hole horizon. When a particle with angular momentum L≠ω a tunnels across the event horizon of Kerr or Kerr-Newman black hole, the angular momentum per unit mass a should be changed. The emission rate of the massless particles under this general case is calculated, and the result is consistent with an underlying unitary theory.
Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole
Wu, S Q; Cai, X.
2002-01-01
Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect...
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
Energy Technology Data Exchange (ETDEWEB)
Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)
2015-09-15
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.
General radiation via tunneling in Kerr and Kerr-Newman black holes
Institute of Scientific and Technical Information of China (English)
GAO Li; LIU WenBiao
2008-01-01
Hawking radiation can be viewed as a process of quantum tunneling near the black hole horizon. When a particle with angular momentum L≠ωa tunnels across the event horizon of Kerr or Kerr-Newman black hole, the angular momentum per unit mass a should be changed. The emission rate of the massless particles under this general case is calculated, and the result is consistent with an underlying unitary theory.
Hawking radiation from an acoustic black hole on an ion ring.
Horstmann, B; Reznik, B; Fagnocchi, S; Cirac, J I
2010-06-25
In this Letter we propose to simulate acoustic black holes with ions in rings. If the ions are rotating with a stationary and inhomogeneous velocity profile, regions can appear where the ion velocity exceeds the group velocity of the phonons. In these regions phonons are trapped like light in black holes, even though we have a discrete field theory and a nonlinear dispersion relation. We study the appearance of Hawking radiation in this setup and propose a scheme to detect it. PMID:20867352
Institute of Scientific and Technical Information of China (English)
Jiang Qing-Quan; Yang Shu-Zheng; Wu Shuang-Qing
2006-01-01
This paper extends Parikh-Wilzcek's recent work, which treats the Hawking radiation as a semi-classical tunnelling process from the event horizon of four dimensional Schwarzshild and Reissner-Nordstr(o)m black holes, to that of arbitrarily dimensional Reissner-Nordstr(o)m de Sitter black hole. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the factually radiant spectrum is no longer precisely thermal after taking the dynamical black hole background and energy conservation into account, but is consistent with the underlying unitary theory and then satisfies the first law of the black hole thermodynamics. Meanwhile, in Parikh-Wilzcek's framework, this paper points out that the information conservation is only suitable for the reversible process but in highly unstable evaporating black hole (irreversible process) the information loss is possible.
Radiating black holes in Einstein-Maxwell-dilaton theory
Aniceto, Pedro; Rocha, Jorge V
2015-01-01
We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a=1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null dust and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a=1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, we prove that an electrically charged black hole in this theory cannot be overcharged by bombarding it with a stream of electrically charged null dust. This provides an example of cosmic censorship observance in a string theory setting.
Hawking radiation as tunneling of vector particles from Kerr-Newman black hole
Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.
2016-03-01
In this paper, by applying the WKB approximation and Hamilton-Jacobi ansatz to the Proca equation, we investigate the tunneling of vector bosons across the event horizon of Kerr-Newman black hole and also the resulting vector particles' Hawking radiation. Universality of the properties of the emitted spectra of different types of particles is established for Kerr-Newman black hole. The coordinate problem for Hawking radiation of the vector particles is also investigated using three coordinate systems. The thermal spectrum of the radiated vector bosons determined using a direct computation corresponds to a temperature which is twice the Hawking temperature of Kerr-Newman black hole for scalar particles. If the well behaved Eddington coordinate system and Painleve coordinate system are used, the correct result of Hawking temperature is obtained. The reason for the discrepancy in the results of naive coordinate and well behaved coordinates is also discussed.
Sadowski, A; Narayan, R; Abarca, D; McKinney, J C
2016-01-01
We present a numerical method which evolves a two-temperature, magnetized, radiative, accretion flow around a black hole, within the framework of general relativistic radiation magnetohydrodynamics. As implemented in the code KORAL, the gas consists of two sub-components -- ions and electrons -- which share the same dynamics but experience independent, relativistically consistent, thermodynamical evolution. The electrons and ions are heated independently according to a standard prescription from the literature for magnetohydrodynamical turbulent dissipation. Energy exchange between the particle species via Coulomb collisions is included. In addition, electrons gain and lose energy and momentum by absorbing and emitting synchrotron and bremsstrahlung radiation, and through Compton scattering. All evolution equations are handled within a fully covariant framework in the relativistic fixed-metric spacetime of the black hole. Numerical results are presented for five models of low luminosity black hole accretion. ...
Supermassive Black Hole Growth and Merger Rates from Cosmological N-body Simulations
Energy Technology Data Exchange (ETDEWEB)
Micic, Miroslav; /Penn State U., Astron. Astrophys.; Holley-Bockelmann, Kelly; /Penn State U.; Sigurdsson, Steinn; /Penn State U., Astron. Astrophys.; Abel, Tom; /SLAC
2007-10-29
Understanding how seed black holes grow into intermediate and supermassive black holes (IMBHs and SMBHs, respectively) has important implications for the duty-cycle of active galactic nuclei (AGN), galaxy evolution, and gravitational wave astronomy. Most studies of the cosmological growth and merger history of black holes have used semianalytic models and have concentrated on SMBH growth in luminous galaxies. Using high resolution cosmological N-body simulations, we track the assembly of black holes over a large range of final masses - from seed black holes to SMBHs - over widely varying dynamical histories. We used the dynamics of dark matter halos to track the evolution of seed black holes in three different gas accretion scenarios. We have found that growth of a Sagittarius A* - size SMBH reaches its maximum mass M{sub SMBH}={approx}10{sup 6}M{sub {circle_dot}} at z{approx}6 through early gaseous accretion episodes, after which it stays at near constant mass. At the same redshift, the duty-cycle of the host AGN ends, hence redshift z=6 marks the transition from an AGN to a starburst galaxy which eventually becomes the Milky Way. By tracking black hole growth as a function of time and mass, we estimate that the IMBH merger rate reaches a maximum of R{sub max}=55 yr{sup -1} at z=11. From IMBH merger rates we calculate N{sub ULX}=7 per Milky Way type galaxy per redshift in redshift range 2 {approx}< z {approx}< 6.
Information Loss and Tunneling Radiation of the Non-Stationary Dilaton-Maxwell Black Hole
Chen, Deyou; Yang, Shuzheng
Taking the self-gravitational interaction and unfixed background space-time into account, we discuss the tunneling radiation of the Dilaton-Maxwell black hole by the Hamilton-Jacobi method. The result shows that the tunneling rate is related not only to the change of Bekenstein-Hawking entropy, but also to a subtle integral about the black hole mass, which does not satisfy the unitary theory and is different from Parikh and Wilczek's result. This implies that information loss in black hole evaporation is possible.
Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie
2016-06-17
The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped. PMID:27367380
Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie
2016-06-17
The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped.
International Nuclear Information System (INIS)
Currently there is a lack of young academics in the nuclear field especially in the field of radiation protection RP. One of the reasons is the very small number of students in the so called STEM subjects (science, technology, engineering and mathematics) which distribute among the different topics in these fields. One important task to overcome the foreseeable shortage of RP professionals is to attract pupils to this field. In routine monitoring the whole body counter of the Institute of Radiation Research (ISF) is used to identify and quantify radioactive materials that are incorporated in the human body using the technique of gamma spectroscopy. The in-vivo monitoring lab participates in activities for pupils at school level, e.g. Kinderuniversitaet, practical studies of secondary level pupils and 'Girls day'. Pupils that come to the lab are ages 14 to 18. The whole body counter is an optimal tool for these children to experience (natural) radioactivity and radiation protection issues. First pupils get a short introduction on radioactivity and gamma spectroscopy at a level adjusted to their current knowledge. After this they are measuring themselves in the whole body counter. A routine measurement of 300 s is able to show the natural occurring K-40 in their bodies. After their own measurements they do calibration measurements using a bottle phantom with a set up adjusted to their own body weights. The bottle phantom is filled with a potassium chloride (KCl) solution and contains no other radioactivity than the natural K-40 content of the KCl. Thus no further radiation protection measures need to be taken for using this phantom. A simple Excel-Sheet is then used to estimate their own K-40 activity by comparing the spectra of their measurement to the ones of the calibration measurements. This 'hands on' experience and the connection of radiation and their own bodies often is a 'eureka' effect and opens discussion on preconceptions of radiation and the need of RP
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Energy Technology Data Exchange (ETDEWEB)
Wang, Peng; Yang, Haitang; Ying, Shuxuan [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China)
2016-01-15
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass m{sub p}. The corrections to the Hawking temperature are calculated for massive and charged particles to O(m{sub p}{sup -2}) and neutral and massless particles with λ = 0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation. (orig.)
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Wang, Peng; Yang, Haitang; Ying, Shuxuan
2016-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass mp. The corrections to the Hawking temperature are calculated for massive and charged particles to {O}( mp^{-2}) and neutral and massless particles with λ =0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation.
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
International Nuclear Information System (INIS)
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass mp. The corrections to the Hawking temperature are calculated for massive and charged particles to O(mp-2) and neutral and massless particles with λ = 0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation. (orig.)
Baco, Sudirman; Harada, Hiroshi; Fukuhara, Riichi
1997-01-01
Since the end of the 1970's, Wagyu producers in southern Kyushu have made efforts in order to improve not only carcass quantity but also carcass quality, introducing a number of AI sires which were produced in another districts that had a hight opinion on carcass quality. A study was conducted to examine effects of such an effort for carcass improvement on the body measurement and reproductivity of a local Japanese Black herd. The records of body measurements and reproductive traits of 1,189 ...
Covariant anomalies and Hawking radiation from Kaluza–Klein AdS black holes
Indian Academy of Sciences (India)
Chuan-Yi Bai
2013-02-01
In this paper, Hawking radiation is studied from four-dimensional (4D) Kaluza–Klein (KK) AdS black holes via the method of anomaly cancellation. The {|bf KK-AdS} black hole considered is a non-extremal charged rotating solution in the theory of 4D gauged supergravity. Its Hawking fluxes of electric charge, angular momentum and energy momentum tensor are derived here. Our results support the common view that Hawking radiation is the quantum effect arising at the event horizon.
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
Energy Technology Data Exchange (ETDEWEB)
Rahman, M. Atiqur, E-mail: atirubd@yahoo.com [Department of Applied Mathematics, Rajshahi University (Bangladesh); Hossain, M. Ilias, E-mail: ilias_math@yahoo.com [Department of Mathematics, Rajshahi University, Rajshahi, 6205 (Bangladesh)
2012-05-30
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.
Hawking radiation of Reissner-Nordstrom-de Sitter black hole by Hamilton-Jacobi method
Hossain, M. Ilias; Rahman, M. Atiqur
2013-01-01
In Refs. (M. Atiqur Rahman, M. Ilias Hossain (2012) Phys. Lett. B {\\bf 712} 1), we have developed Hamilton-Jacobi method for dynamical spacetime and discussed Hawking radiation of Schwarzschild-de Sitter black hole by massive particle tunneling method. In this letter, we have investigated the hawking purely thermal and nonthermal radiations of Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole. We have considered energy and angular momentum as conserved and shown that the tunneling rate is re...
Hawking Radiation of Schwarzschild-de Sitter Black Hole by Hamilton-Jacobi method
Rahman, M Atiqur; 10.1016/j.physletb.2012.04.049
2012-01-01
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek\\rq s opinion and gives a correction to the Hawking radiation of SdS black hole.
A New Method to Study the Hawking Radiation from the Kerr-NUT Black Hole
Liu, Hong-Lin; Liu, Zi-Xiang; Hou, Jian-Song; Yang, Shu-Zheng
2008-11-01
Developing Hamilton-Jacobi method, we discuss the Hawking radiation of Kerr-NUT black hole by considering the self-gravitation interaction as well as the energy conservation and angular momentum conservation. The result shows that the factual spectrum deviates from the precisely thermal one and the tunneling rate is related to the change of Bekenstein-Hawking entropy, which is accordant with that obtained by Parikh and Wilczek’s method and gives an interesting correction to the Hawking radiation of the black hole.
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
Rahman, M. Atiqur; Hossain, M. Ilias
2012-05-01
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
International Nuclear Information System (INIS)
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.
Quantum Radiation Properties of Dirac Particles in General Nonstationary Black Holes
Directory of Open Access Journals (Sweden)
Jia-Chen Hua
2014-01-01
Full Text Available Quantum radiation properties of Dirac particles in general nonstationary black holes in the general case are investigated by both using the method of generalized tortoise coordinate transformation and considering simultaneously the asymptotic behaviors of the first-order and second-order forms of Dirac equation near the event horizon. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we give a general expression of the new extra coupling effect in thermal radiation spectrum of Dirac particles which is absent from the thermal radiation spectrum of scalar particles. Also, we reveal a relationship that is ignored before between thermal radiation and nonthermal radiation in the case of scalar particles, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of scalar particles in nonthermal radiation for general nonstationary black holes.
Body and diet composition of sympatric black and grizzly bears in the Greater Yellowstone Ecosystem
Schwartz, Charles C.; Fortin, Jennifer K.; Teisberg, Justin E.; Haroldson, Mark A.; Servheen, Christopher; Robbins, Charles T.; van Manen, Frank T.
2013-01-01
The Greater Yellowstone Ecosystem (GYE) has experienced changes in the distribution and availability of grizzly bear (Ursus arctos) food resources in recent decades. The decline of ungulates, fish, and whitebark pine seeds (Pinus albicaulis) has prompted questions regarding their ability to adapt. We examined body composition and diet of grizzly bears using bioelectrical impedance and stable isotopes to determine if 1) we can detect a change in diet quality associated with the decline in either ungulates or whitebark pine, and 2) the combined decline in ungulates, fish, and pine seeds resulted in a change in grizzly bear carrying capacity in the GYE. We contrasted body fat and mass in grizzly bears with a potential competitor, the American black bear (Ursus americanus), to address these questions. Grizzly bears assimilated more meat into their diet and were in better body condition than black bears throughout the study period, indicating the decline in ungulate resources did not affect grizzly bears more than black bears. We also found no difference in autumn fat levels in grizzly bears in years of good or poor pine seed production, and stable isotope analyses revealed this was primarily a function of switching to meat resources during poor seed-producing years. This dietary plasticity was consistent over the course of our study. We did not detect an overall downward trend in either body mass or the fraction of meat assimilated into the diet by grizzly bears over the past decade, but we did detect a downward trend in percent body fat in adult female grizzly bears after 2006. Whether this decline is an artifact of small sample size or due to the population reaching the ecological carrying capacity of the Yellowstone ecosystem warrants further investigation.
Hod, Shahar
2015-01-01
The holographic principle has taught us that, as far as their entropy content is concerned, black holes in $(3+1)$-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat $(2+1)$-dimensional spacetimes. In this essay we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordstr\\"om black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine $(3+1)$-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the $(3+1)$-dimensional black holes effectively behave as p...
Shuang-Qing, W; Shuang-Qing, Wu; Mu-Lin, Yan
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.
Analog Hawking radiation from an acoustic black hole in a flowing polariton superfluid
Gerace, Dario; Carusotto, Iacopo
2012-01-01
We theoretically study Hawking radiation processes from an analog acoustic black hole in a flowing superfluid of exciton-polaritons in a one-dimensional semiconductor microcavity. Polaritons are coherently injected into the microcavity by a laser pump with a suitably tailored spot profile. An event horizon with a large analog surface gravity is created by inserting a defect in the polariton flow along the cavity plane. Experimentally observable signatures of the analog Hawking radiation are i...
Cardoso, Vitor(CENTRA, Departamento de F´ısica, Instituto Superior Técnico, Universidade de Lisboa — UL, Av. Rovisco Pais 1, 1049, Lisboa, Portugal); Lemos, José P. S.
2002-01-01
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss possible connections between these ...
Tunneling Radiation of Vector Particles in Four and Five Dimensional Black Holes
Chen, Bingbing
2016-07-01
Recent research shows that the WKB approximation and the Hamilton-Jacobi method has been succeed in studying the tunneling radiation of vector particles. In view of this, our main aim in this letter is to study the Proca equation and the vector particles tunneling radiation in the 4-dimensional and 5-dimensional black holes. And finally, the results here show that the temperature of vector particle is the same as Dirac particle's and other particle's.
Institute of Scientific and Technical Information of China (English)
吴双清; 闫沐霖
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated using a method of the generalized tortoise coordinate transformation.Both the location and temperature of the event horizon depend on the time and on the angles.They are in agreement with the previous results,but thethermal radiation spectrum of massless spinor particles displays a type of spin-acceleration coupling effect.
Hawking radiation from the dilaton-(anti) de Sitter black hole via covariant anomaly
Institute of Scientific and Technical Information of China (English)
Han Yi-Wen; Bao Zhi-Qing; Hong Yun
2009-01-01
Adopting the anomaly cancellation method, initiated by Robinson and Wilczek recently, this paper discusses Hawking radiation from the dilaton-(anti) de Sitter black hole. To save the underlying gauge and general covariance, it introduces covariant fluxes of gauge and energy-momentum tensor to cancel the gauge and gravitational anomalies. The result shows that the introduced compensating fluxes are equivalent to those of a 2-dimensional blackbody radiation at Hawking temperature with appropriate chemical potential.
A public code for general relativistic, polarised radiative transfer around spinning black holes
Dexter, Jason
2016-01-01
Ray tracing radiative transfer is a powerful method for comparing theoretical models of black hole accretion flows and jets with observations. We present a public code, grtrans, for carrying out such calculations in the Kerr metric, including the full treatment of polarised radiative transfer and parallel transport along geodesics. The code is written in Fortran 90 and efficiently parallelises with OpenMP, and the full code and several components have Python interfaces. We describe several te...
The modes of death in mammals exposed to whole body radiation (acute radiation syndromes)
International Nuclear Information System (INIS)
When an animal is exposed to a sufficient amount of radiation, there will be changes in many organs of the body, and as a result of either the effects in one particular organ or the interaction of effects in several organs, the animal as a whole will show characteristic syndromes. Some syndromes result inevitably in death. Others may or may not be lethal, depending on the extent of the tissue damage. The time of appearance of the syndromes, their duration, and the survival of the organism depend on many factors. Whole body acute doses of radiation produce the same spectrum of Central Nervous System (CNS), Gastrointestinal (GI) and Bone Marrow (BM) injury in man as was described for animals. Damage to the skin, ovary and testis are an integral and important part of the symptoms. (author)
Nagatani, Y
2001-01-01
We show that a spherical electroweak domain wall is formed around a small black hole and this is a general property of the Hawking radiation in the vacuum of the Standard Model. The wall appears not only for the first order phase transition in the electroweak theory but also for the second order one because the black hole heats up its neighborhood locally by the Hawking radiation in any case. We propose a model for unifying the origin of the baryon number and the cold dark matter in our universe by using properties of the primordial black hole with a mass of several hundred kilograms. The interaction between our wall and the Hawking-radiated-particles can create a baryon number which is proportional to the mass of the black hole as well as the CP broken phase in the extension of the Standard Model. Our model can explain both the baryon-entropy ratio B/S \\sim 10^{-10} and the energy density of the dark matter, provided that the following three conditions are satisfied: (i) the primordial black holes dominate i...
Fisenko, Anatoliy I
2015-01-01
The general analytical expressions for the thermal radiative and thermodynamic properties of a real-body are obtained in a finite range of frequencies at different temperatures. The frequency dependence of the spectral emissivity is represented as a power series. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible-near infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The g...
Hawking Radiation of Topological Massive Warped-AdS3 Black Holes via Particles Tunnelling
Gecim, Ganim
2014-01-01
We investigate the Dirac and scalar particles tunnelling as a radiation of Warped AdS3 black holes in Topological Massive Gravity. Using Hamilton-Jacobi method, we discuss tunnelling probability and Hawking temperature of the spin-1/2 and spin-0 particles for the black hole. We observe the tunnelling probability and Hawking temperature to be same for the spin-1/2 and spin-0. We also examined the same procedure for the extremal case of the Warped AdS3 black holes, and thus, we show that the tunnelling process may occur, for both Dirac and scalar particles. Furthermore, in the extremal case, we find that the extremal case of the black hole has the Hawking Temperature in the Planck scale and thus it has a surface gravity although it has no surface gravity according to the classical method.
Quasinormal modes of BTZ black hole and Hawking-like radiation in graphene
Kandemir, B S
2016-01-01
The Ba\\~{n}ados-Teitelboim-Zanelli (BTZ) black hole model corresponds to a solution of (2+1)-dimensional Einstein gravity with negative cosmological constant, and by a conformal rescaling its metric can be mapped onto the hyperbolic pseudosphere surface (Beltrami trumpet) with negative curvature. Beltrami trumpet shaped graphene sheets have been predicted to emit Hawking radiation that is experimentally detectable by a scanning tunnelling microscope. Here, for the first time we present an analytical algorithm that allows variational solutions to the Dirac Hamiltonian of graphene pseudoparticles in BTZ black hole gravitational field by using an approach based on the formalism of pseudo-Hermitian Hamiltonians within a discrete-basis-set method. We show that our model not only reproduces the exact results for the real part of quasinormal mode frequencies of (2+1)-dimensional spinless BTZ black hole, but also provides analytical results for the real part of quasinormal modes of spinning BTZ black hole, and also o...
Hawking Radiation from a Vaidya Black Hole: A Semi-Classical Approach and Beyond
Siahaan, Haryanto M
2008-01-01
We derive the Hawking radiation for Vaidya black hole in the tunneling picture from the corresponding single particle action by the use of the radial null geodesic and the Hamilton-Jacobi method (beyond semi-classical approximation). Both results are then analyzed and compared.
Hawking radiation from Kerr-Newman-Kasuya black hole via quantum anomalies
Institute of Scientific and Technical Information of China (English)
He Tang-Mei; Fan Jun-Hui; Wang Yong-Jiu
2008-01-01
We have studied the Hawking radiation of the Kerr-Newman-Kasuya black hole via gauge and gravitational anomaly in the dragging coordinates. The fluxes of the electromagnetic current and the energy momentum tensor for each partial wave in two-dimensional field are obtained.
Fisenko, Anatoliy I.; Lemberg, Vladimir
2015-11-01
There are several classes of materials and space objects for which the frequency dependence of the spectral emissivity is represented as a power series. Therefore, the study of the properties of thermal radiation for these real bodies is an important task for both fundamental science and industrial applications. The general analytical expressions for the thermal radiative and thermodynamic functions of a real body are obtained in a finite range of frequencies at different temperatures. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The obtained general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible and near-infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The general analytical expressions obtained can easily be presented in the wavenumber domain.
Konstantinidis, Symeon; Amaro-Seoane, Pau; Kokkotas, Kostas D.
2013-09-01
Context. Unlike supermassive and stellar-mass black holes (SBHs), the existence of intermediate-mass black holes (IMBHs) with masses ranging between 102-5 M⊙ has not yet been confirmed. The main problem in the detection is that the innermost stellar kinematics of globular clusters (GCs) or small galaxies, the possible natural loci to IMBHs, are very difficult to resolve. However, if IMBHs reside in the centre of GCs, a possibility is that they interact dynamically with their environment. A binary formed with the IMBH and a compact object of the GC would naturally lead to a prominent source of gravitational radiation, detectable with future observatories. Aims: We use N-body simulations to study the evolution of GCs containing an IMBH and calculate the gravitational radiation emitted from dynamically formed IMBH-SBH binaries and the possibility that the IMBH escapes the GC after an IMBH-SBH merger. Methods: We ran for the first time direct-summation integrations of GCs with an IMBH including the dynamical evolution of the IMBH with the stellar system and relativistic effects, such as energy loss in gravitational waves (GWs) and periapsis shift, and gravitational recoil. Results: We find in one of our models an intermediate mass-ratio inspiral (IMRI), which leads to a merger with a recoiling velocity higher than the escape velocity of the GC. The GWs emitted fall in the range of frequencies that a LISA-like observatory could detect, like the European eLISA or with mission options considered in the recent preliminary mission study conducted in China. The merger has an impact on the global dynamics of the cluster, as an important heating source is removed when the merged system leaves the GC. The detection of one IMRI would constitute a test of GR, as well as an irrefutable proof of the existence of IMBHs.
Institute of Scientific and Technical Information of China (English)
吴涧; 蒋维楣; 符淙斌; 苏炳凯; 刘红年; 汤剑平
2004-01-01
As part of the development work of the Chinese new regional climate model (RIEMS), the radiative process of black carbon (BC) aerosols has been introduced into the original radiative procedures of RIEMS,and the transport model of BC aerosols has also been established and combined with the RIEMS model.Using the new model system, the distribution of black carbon aerosols and their radiative effect over the China region are investigated. The influences of BC aerosole on the atmospheric radiative transfer and on the air temperature, land surface temperature, and total rainfall are analyzed. It is found that BC aerosols induce a positive radiative forcing at the top of the atmosphere (TOA), which is dominated by shortwave radiative forcing. The maximum radiative forcing occurs in North China in July and in South China in April. At the same time, negative radiative forcing is observed on the surface. Based on the radiative forcing comparison between clear sky and cloudy sky, it is found that cloud can enforce the TOA positive radiative forcing and decrease the negative surface radiative forcing. The responses of the climate system in July to the radiative forcing due to BC aerosols are the decrease in the air temperature in the middle and lower reaches of the Changjiang River and Huaihe area and most areas of South China, and the weak increase or decrease in air temperature over North China. The total rainfall in the middle and lower reaches of the Changjiang River area is increased, but it decreased in North China in July.
Black carbon fractal morphology and short-wave radiative impact: a modelling study
Directory of Open Access Journals (Sweden)
M. Kahnert
2011-08-01
Full Text Available We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of differences in the optical cross sections and asymmetry parameters. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably
Hinderer, Tanja; Mroué, Abdul H; Hemberger, Daniel A; Lovelace, Geoffrey; Pfeiffer, Harald P
2013-01-01
We compute the periastron advance using the effective-one-body formalism for binary black holes moving on quasi-circular orbits and having spins collinear with the orbital angular momentum. We compare the predictions with the periastron advance recently computed in accurate numerical-relativity simulations and find remarkable agreement for a wide range of spins and mass ratios. These results do not use any numerical-relativity calibration of the effective-one-body model, and stem from two key ingredients in the effective-one-body Hamiltonian: (i) the mapping of the two-body dynamics of spinning particles onto the dynamics of an effective spinning particle in a (deformed) Kerr spacetime, fully symmetrized with respect to the two-body masses and spins, and (ii) the resummation, in the test-particle limit, of all post-Newtonian (PN) corrections linear in the spin of the particle. In fact, even when only the leading spin PN corrections are included in the effective-one-body spinning Hamiltonian but all the test-p...
Lan, X. G.; Jiang, Q. Q.; Wei, L. F.
2012-04-01
We apply the Damour-Ruffini-Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future.
Black hole radiation of massive spin-2 particles in (3+1) dimensions
Sakalli, I.; Övgün, A.
2016-06-01
This paper is devoted to the study of radiation of a massive spin-2 boson (graviton with a nonzero mass) through the event horizon of a generic static and spherically symmetric black hole in (3+1) dimensions. To this end, we consider the problem in the framework of the quantum tunneling phenomenon. We evaluate the tunneling rate of the massive gravitons by applying the semiclassical WKB approximation to the Fierz-Pauli equation. The temperature of the radiation is obtained with the aid of the Boltzmann expression. Our findings are in good agreement with the existing Hawking radiation studies in the current literature.
Black hole radiation of massive spin-2 particles in (3+1) dimensions
Sakalli, I
2016-01-01
This paper is devoted to the study of radiation of massive spin-2 boson (graviton with a nonzero mass) through the event horizon of a generic static and spherically symmetric black hole in (3+1) dimensions. To this end, we consider the problem in the framework of quantum tunneling phenomenon. We evaluate the tunneling rate of the massive gravitons by applying the semiclassical WKB approximation to the Fierz-Pauli equation. The temperature of the radiation is obtained with the aid of the Boltzmann expression. Our findings are in good agreement with the existing Hawking radiation studies in the current literature.
Yang, Shuzheng; Chen, Deyou
2007-07-01
The tunneling radiation of Ressiner-Nordström black hole is studied by developing Hamilton-Jacobi method. The result shows the actual radiation spectrum deviates from the pure thermal one and the tunneling probability are related to the change of Bekenstein-Hawking entropy, which is accordant with Parikh and Wilczek's and gives a new method to correct Hawking pure thermal radiation of Ressiner-Nordström black hole.
Particle transport in magnetized media around black holes and associated radiation
Vieyro, Florencia L
2012-01-01
Galactic black hole coronae are composed of a hot, magnetized plasma. The spectral energy distribution produced in this component of X-ray binaries can be strongly affected by different interactions between locally injected relativistic particles and the matter, radiation and magnetic fields in the source. We study the non-thermal processes driven by the injection of relativistic particles into a strongly magnetized corona around an accreting black hole. We compute in a self-consistent way the effects of relativistic bremsstrahlung, inverse Compton scattering, synchrotron radiation, and the pair-production/annihilation of leptons, as well as hadronic interactions. Our goal is to determine the non-thermal broadband radiative output of the corona. The set of coupled kinetic equations for electrons, positrons, protons, and photons are solved and the resulting particle distributions are computed self-consistently. The spectral energy distributions of transient events in X-ray binaries are calculated, as well as t...
Black Hole Formation in Primordial Galaxies : Chemical and Radiative Conditions
Schleicher, Dominik R. G.; Spaans, Marco; Glover, Simon C. O.
2010-01-01
In massive primordial galaxies, the gas may directly collapse and form a single central massive object if cooling is suppressed. H(2) line cooling can be suppressed in the presence of a strong soft-ultraviolet radiation field, but the role played by other cooling mechanisms is less clear. In optical
Hawking radiation as tunneling from charged black holes in 0A string theory
Energy Technology Data Exchange (ETDEWEB)
Kim, Hongbin, E-mail: hongbin@yonsei.ac.kr [Department of Physics, College of Science, Yonsei University, Seoul 120-749 (Korea, Republic of)
2011-09-01
There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.
Hawking radiation as tunneling from charged black holes in 0A string theory
Kim, Hongbin
2011-01-01
There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitional picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.
Cosmic background radiation in the vicinity of a Schwarzschild black hole: No classic firewall
Wielgus, M.; Ellis, G. F. R.; Vincent, F. H.; Abramowicz, M. A.
2014-12-01
The cosmic blackbody background radiation pervades the entire Universe, and so falls into every astrophysical black hole. The blueshift of the infalling photons, measured by a static observer, is infinite at the event horizon. This raises a question as to whether a "firewall" of high energy density may form just outside the horizon, or whether the effect can be attributed exclusively to a singular behavior of the static observer's frame at the horizon. In principle, the presence of such a firewall may alter the motion of the infalling matter, influence the black hole evolution, or even invalidate the vacuum Einstein field equation solution as a realistic approximation for black holes. In this paper we show by means of analytic calculations that all these effects indeed exist, but their magnitude is typically negligibly small, even though the matter stress tensor is divergent in the static frame at r =2 M . That is not surprising because of the divergent relation of that frame to a freely falling frame as r →2 M ; however, it represents a kind of classical analogue for the black hole complementarity principle that has been proposed for quantum effects near a black hole. What is perhaps more surprising is the divergence of the radiation stress tensor for massive particles moving on circular geodesic orbits for values of r approaching r =3 M . However such orbits will not occur for infalling matter in realistic accretion discs.
Hawking radiation as tunneling from charged black holes in 0A string theory
International Nuclear Information System (INIS)
There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.
Ruangsri, Uchupol; Vigeland, Sarah J.; Hughes, Scott A.
2015-01-01
A small body orbiting a black hole follows a trajectory that, at leading order, is a geodesic of the black hole spacetime. Much effort has gone into computing "self force" corrections to this motion, arising from the small body's own contributions to the system's spacetime. Another correction to the motion arises from coupling of the small body's spin to the black hole's spacetime curvature. Spin-curvature coupling drives a precession of the small body, and introduces a "force" (relative to t...
Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?
Directory of Open Access Journals (Sweden)
Laura Mersini-Houghton
2014-11-01
Full Text Available Particle creation leading to Hawking radiation is produced by the changing gravitational field of the collapsing star. The two main initial conditions in the far past placed on the quantum field from which particles arise, are the Hartle–Hawking vacuum and the Unruh vacuum. The former leads to a time-symmetric thermal bath of radiation, while the latter to a flux of radiation coming out of the collapsing star. The energy of Hawking radiation in the interior of the collapsing star is negative and equal in magnitude to its value at future infinity. This work investigates the backreaction of Hawking radiation on the interior of a gravitationally collapsing star, in a Hartle–Hawking initial vacuum. It shows that due to the negative energy Hawking radiation in the interior, the collapse of the star stops at a finite radius, before the singularity and the event horizon of a black hole have a chance to form. That is, the star bounces instead of collapsing to a black hole. A trapped surface near the last stage of the star's collapse to its minimum size may still exist temporarily. Its formation depends on the details of collapse. Results for the case of Hawking flux of radiation with the Unruh initial state, will be given in a companion paper II.
Universality, maximum radiation, and absorption in high-energy collisions of black holes with spin.
Sperhake, Ulrich; Berti, Emanuele; Cardoso, Vitor; Pretorius, Frans
2013-07-26
We explore the impact of black hole spins on the dynamics of high-energy black hole collisions. We report results from numerical simulations with γ factors up to 2.49 and dimensionless spin parameter χ=+0.85, +0.6, 0, -0.6, -0.85. We find that the scattering threshold becomes independent of spin at large center-of-mass energies, confirming previous conjectures that structure does not matter in ultrarelativistic collisions. It has further been argued that in this limit all of the kinetic energy of the system may be radiated by fine tuning the impact parameter to threshold. On the contrary, we find that only about 60% of the kinetic energy is radiated for γ=2.49. By monitoring apparent horizons before and after scattering events we show that the "missing energy" is absorbed by the individual black holes in the encounter, and moreover the individual black-hole spins change significantly. We support this conclusion with perturbative calculations. An extrapolation of our results to the limit γ→∞ suggests that about half of the center-of-mass energy of the system can be emitted in gravitational radiation, while the rest must be converted into rest-mass and spin energy.
Hawking Radiation of a Quantum Black Hole in an Inflationary Universe
Huang, W H
1992-01-01
The quantum stress-energy tensor of a massless scalar field propagating in the two-dimensional Vaidya-de Sitter metric, which describes a classical model spacetime for a dynamical evaporating black hole in an inflationary universe, is analyzed. We present a possible way to obtain the Hawking radiation terms for the model with arbitrary functions of mass. It is used to see how the expansion of universe will affect the dynamical process of black hole evaporation. The results show that the cosmological inflation has an inclination to depress the black hole evaporation. However, if the cosmological constant is sufficiently large then the back-reaction effect has the inclination to increase the black hole evaporation. We also present a simple method to show that it will always produce a divergent flux of outgoing radiation along the Cauchy horizon where the curvature is a finite value. This means that the Hawking radiation will be very large in there and shall modify the classical spacetime drastically. Therefore ...
Backreaction on moving mirrors and black hole radiation
Tuning, N; Tuning, Niels; Verlinde, Herman
1996-01-01
We compute the effect of quantum mechanical backreaction on the spectrum of radiation in a dynamical moving mirror model, mimicking the effect of a gravitational collapse geometry. Our method is based on the use of a combined WKB and saddle-point approximation to implement energy conservation in the calculation of the Bogolyubov coefficients, in which we assume that the mirror particle has finite mass m. We compute the temperature of the produced radiation as a function of time and find that after a relatively short time, the temperature is reduced by a factor 1/2 relative to the standard result. We comment on the application of this method to two-dimensional dilaton gravity with a reflecting boundary, and conclude that the WKB approximation quickly breaks down due to the appearance of naked singularities and/or white hole space-times for the relevant WKB-trajectories.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Mc Caughey, Eamon
2016-04-01
The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined.
Yang, Shu-Zheng; Chen, De-You
2007-01-01
Taking the self-gravitation interaction and energy conservation, charge conservation and angular momentum conservation into account, we discuss the tunnelling characteristics of the charged particle from Sen black hole by the Hamilton-Jacobi method. The result shows that the tunnelling probability is related to the change of Bekenstein-Hawking entropy, and the actual radiation spectrum deviates from the pure thermal one, which is consistent with the result of Parikh and Wilczek and gives a new method to correct the Hawking pure thermal spectrum of Sen black hole.
Hawking radiation of the Vaidya-Bonner-de Sitter black hole
Energy Technology Data Exchange (ETDEWEB)
Chen Deyou; Yang Shuzheng [Institute of Theoretical Physics, China West Normal University, Nanchong, Sichuan 637002 (China)
2007-08-15
Considering the unfixed background space-time and the self-gravitational interaction, we view the Hawking radiation of the Vaidya-Bonner- de Sitter black hole by the Hamilton-Jacobi method and the radial geodesic method. The result shows the tunneling rate is related not only to the change of Bekenstein-Hawking entropy but also to the integral of the black hole mass and charge, which does not satisfy the unitary theory and is not in accordance with the known result.
A Novel Parametric Bound for Information Retrieval from Black Hole Radiation
Roy, Avik; Alvi, Mishkat Al; Majumdar, Mahbub; Matin, Md Abdul
2013-01-01
Hawking's argument about non-unitary evolution of black holes is often questioned on the ground that it doesn't acknowledge the quantum correlations in radiation process. However, recently it has been shown that adding `small' correction to leading order Hawking analysis, accounting for the correlations, doesn't help to restore unitarity. This paper generalizes the bound on entanglement entropy by relaxing the `smallness' condition and configures the parameters for possible recovery of information from an evaporating black hole. The new bound effectively puts an upper limit on increase in entanglement entropy. It also facilitates to relate the change in entanglement entropy to the amount of correction to Hawking state.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Mc Caughey, Eamon [Dublin Institute of Technology, School of Mathematical Sciences, Dublin 8 (Ireland)
2016-04-15
The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined. (orig.)
Hawking radiation as quantum tunneling from a noncommutative Schwarzschild black hole
International Nuclear Information System (INIS)
We study the tunneling process through the quantum horizon of a Schwarzschild black hole in noncommutative spacetime. This is done by considering the effect of smearing of the particle mass as a Gaussian profile in flat spacetime. We show that even in this noncommutative setup there will be no correlation between the different modes of radiation, which reflects the fact that information does not come out continuously during the evaporation process at least at late time. However, due to spacetime noncommutativity, information might be preserved by a stable black hole remnant
Hawking radiation as quantum tunneling from a noncommutative Schwarzschild black hole
Energy Technology Data Exchange (ETDEWEB)
Nozari, Kourosh; Mehdipour, S Hamid [Department of Physics, Faculty of Basic Sciences, University of Mazandaran, PO Box 47416-1467, Babolsar (Iran, Islamic Republic of)], E-mail: knozari@umz.ac.ir, E-mail: h.mehdipour@umz.ac.ir
2008-09-07
We study the tunneling process through the quantum horizon of a Schwarzschild black hole in noncommutative spacetime. This is done by considering the effect of smearing of the particle mass as a Gaussian profile in flat spacetime. We show that even in this noncommutative setup there will be no correlation between the different modes of radiation, which reflects the fact that information does not come out continuously during the evaporation process at least at late time. However, due to spacetime noncommutativity, information might be preserved by a stable black hole remnant.
Institute of Scientific and Technical Information of China (English)
YANG Shu-Zheng; CHEN De-You
2007-01-01
@@ Taking the self-gravitation interaction and energy conservation, charge conservation and angular momentum conservation into account, we discuss the tunnelling characteristics of the charged particle from Sen black hole by the Hamilton-Jacobi method. The result shows that the tunnelling probability is related to the change of Bekenstein-Hawking entropy, and the actual radiation spectrum deviates from the pure thermal one, which is consistent with the result of Parikh and Wilczek and gives a new method to correct the Hawking pure thermal spectrum of Sen black hole.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Caughey, Eamon Mc
2016-01-01
The radial motion of massive particles in the equatorial plane of the Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both insides and outside the ergosphere) and their effects on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient is determined.
Potency preservation following stereotactic body radiation therapy for prostate cancer
International Nuclear Information System (INIS)
Erectile dysfunction after prostate radiation therapy remains an ongoing challenge and critical quality of life issue. Given the higher dose of radiation per fraction using stereotactic body radiation therapy (SBRT) there is concern that post-SBRT impotency would be higher than conventional radiation therapy approaches. This study sought to evaluate potency preservation and sexual function following SBRT for prostate cancer. Between February 2008 and March 2011, 216 men with clinically localized prostate cancer were treated definitively with SBRT monotherapy at Georgetown University Hospital. Potency was defined as the ability to have an erection firm enough for intercourse with or without sexual aids while sexual activity was defined as the ability to have an erection firm enough for masturbation and foreplay. Patients who received androgen deprivation therapy (ADT) were excluded from this study. Ninety-seven hormone-naïve men were identified as being potent at the initiation of therapy and were included in this review. All patients were treated to 35–36.25 Gy in 5 fractions delivered with the CyberKnife Radiosurgical System (Accuray). Prostate specific antigen (PSA) and total testosterone levels were obtained pre-treatment, every 3 months for the first year and every 6 months for the subsequent year. Sexual function was assessed with the Sexual Health Inventory for Men (SHIM), the Expanded Prostate Index Composite (EPIC)-26 and Utilization of Sexual Medication/Device questionnaires at baseline and all follow-up visits. Ninety-seven men (43 low-, 50 intermediate- and 4 high-risk) at a median age of 68 years (range, 48–82 years) received SBRT. The median pre-treatment PSA was 5.9 ng/ml and the minimum follow-up was 24 months. The median pre-treatment total serum testosterone level was 11.4 nmol/L (range, 4.4-27.9 nmol/L). The median baseline SHIM was 22 and 36% of patients utilized sexual aids prior to treatment. Although potency rates declined following
Tidal disruption rate of stars by supermassive black holes obtained by direct N-body simulations
Brockamp, M; Kroupa, P
2011-01-01
The disruption rate of stars by supermassive black holes (SMBHs) is calculated numerically with a modified version of Aarseth's NBODY6 code. The initial stellar distribution around the SMBH follows a S\\'{e}rsic n=4 profile representing bulges and early type galaxies. In order to infer relaxation driven effects and to increase the statistical significance, a very large set of N-body integrations with different particle numbers N, ranging from 10^{3} to 0.5 \\cdot 10^{6} particles, is performed. Three different black hole capture radii are taken into account, enabling us to scale these results to a broad range of astrophysical systems with relaxation times shorter than one Hubble time, i.e. for SMBHs up to M_bh \\approx 10^{7} M_sun. The computed number of disrupted stars are driven by diffusion in angular momentum space into the loss cone of the black hole and the rate scales with the total number of particles as dN/dt \\propto N^{b}, where b is as large as 0.83. This is significantly steeper than the expected sc...
In vivo evaluation of black and green tea dermal products against UV radiation.
Türkoğlu, M; Uğurlu, T; Gedik, G; Yılmaz, A M; Süha Yalçin, A
2010-10-01
Aqueous extracts of black and green tea (Camellia sinensis) were obtained by freeze-drying for this study. The extracts were evaluated based on tea quality control tests, UV, IR scans, and in vitro antioxidant capacity tests. Dermal products from the tea extracts were designed and manufactured. Black and green tea gels were tested in vivo in the forearms of six subjects using an artifical UV (200-400 nm) source. The tested formulations were green tea gel, black tea gel, 0.3% caffeine gel, carbomer gel base, and a control. Depending on tea quality, the samples resulted in water soluble fractions of 24.5-39.5%. UV and IR scans specifically showed peaks for alkaloids like caffeine, catechins such as epigallocatechin gallate, and polyphenols with dimeric and polymeric structures such as theaflavins (TFs) and thearubigins (TRs). Antioxidant and free radical scavenging activities of black and green tea samples were found to be high and comparable; activity levels for black tea, green tea, high quality black tea, and L-ascorbic acid were 0.48, 0.50, 0.82, and 1.32 mM TR/mg, respectively. No UV-induced erythema was observed at the black and green tea gel sites in any of the subjects. UV-induced erythema was consistently present in various grades at caffeine gel, carbomer gel, and control sites. Results led to the conclusion that freeze-dried black and green tea extracts had strong UV absorbance. Formulating those extracts into dermal gels protected the skin against UV-induced erythema. Therefore, tea extracts were found to be promising candidates for their ability to protect against the harmful effects of UV radiation, such as erythema and premature aging of the skin.
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Free-fall Frame
Wang, Peng; Ying, Shuxuan
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass $m_{p}$. The corrections to the Hawking temperature are calculated for massive and charged particles to $\\mathcal{O}\\left( m_{p}^{-2}\\right) $ and neutral and massless particles with $\\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is...
Dysuria Following Stereotactic Body Radiation Therapy for Prostate Cancer
Directory of Open Access Journals (Sweden)
Einsley-Marie eJanowski
2015-07-01
Full Text Available Background: Dysuria following prostate radiation therapy is a common toxicity that adversely affects patients’ quality of life and may be difficult to manage. Methods: 204 patients treated with stereotactic body radiation therapy (SBRT from 2007 to 2010 for localized prostate carcinoma with a minimum follow up of three years were included in this retrospective review of prospectively collected data. All patients were treated to 35-36.25Gy in 5 fractions delivered with robotic SBRT with real time fiducial tracking. Dysuria and other lower urinary tract symptoms were assessed via Question 4b (Pain or burning on urination of the Expanded Prostate Index Composite (EPIC-26 and the American Urological Association (AUA Symptom Score at baseline and at routine follow up. Results: 204 patients (82 low-, 105 intermediate-, and 17 high risk according to the D’Amico classification at a median age of 69 years (range 48-91 received SBRT for their localized prostate cancer with a median follow up of 47 months. Bother associated with dysuria significantly increased from a baseline of 12% to a maximum of 43% at one month (p<0.0001. There were two distinct peaks of moderate to severe dysuria bother at 1 month and at 6-12 months, with 9% of patients experiencing a late transient dysuria flare. While a low level of dysuria was seen through the first two years of follow-up, it returned to below baseline by two years (p=0.91. The median baseline AUA score of 7.5 significantly increased to 11 at 1 month (p<0.0001 and returned to 7 at 3 months (p= 0.54. Patients with dysuria had a statistically higher AUA score at baseline and at all follow-ups up to 30 months. Dysuria significantly correlated with dose and AUA score on multivariate analysis. Frequency and strain significantly correlated with dysuria on stepwise multivariate analysis.Conclusions: The rate and severity of dysuria following SBRT is comparable to patients treated with other radiation modalities.
Hawking Radiation of Mass Generating Particles From Dyonic Reissner Nordstrom Black Hole
Sakalli, I
2016-01-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordstr\\"{o}m black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed to read the standard Hawking temperature of the dyonic Reissner-Nordstr\\"{o}m black hole.
Hawking Radiation of Mass Generating Particles from Dyonic Reissner-Nordström Black Hole
Sakalli, I.; Övgün, A.
2016-09-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyse the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordström black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed in reading the standard Hawking temperature of the dyonic Reissner-Nordström black hole.
Gravitational-wave energy and radiation reaction on quasi-spherical black holes
Hayward, S A
2000-01-01
Gravitational waves are given a local definition in a quasi-spherical approximation, describing roughly spherical but otherwise dynamical astrophysical objects, such as a black hole forming by binary black-hole coalescence. A local effective energy tensor is defined for the gravitational waves, satisfying standard energy conditions. Radiation reaction, such as the back-reaction of the gravitational waves on the black hole, may then be described by including the gravitational-wave energy tensor as a source in the truncated Einstein equations. This can be formulated as a second quasi-spherical approximation, which retains non-linear terms in the fields encoding the gravitational waves. The energy-momentum in a canonical frame is covariantly conserved. The strain to be measured by a distant detector is simply defined.
Simulations of recoiling black holes: adaptive mesh refinement and radiative transfer
Meliani, Zakaria; Olivares, Hector; Porth, Oliver; Rezzolla, Luciano; Younsi, Ziri
2016-01-01
(Abridged) We here continue our effort to model the behaviour of matter when orbiting or accreting onto a generic black hole by developing a new numerical code employing advanced techniques geared solve the equations of in general-relativistic hydrodynamics. The new code employs a number of high-resolution shock-capturing Riemann-solvers and reconstruction algorithms, exploiting the enhanced accuracy and the reduced computational cost of AMR techniques. In addition, the code makes use of sophisticated ray-tracing libraries that, coupled with general-relativistic radiation-transfer calculations, allow us to compute accurately the electromagnetic emissions from such accretion flows. We validate the new code by presenting an extensive series of stationary accretion flows either in spherical or axial symmetry and performed either in 2D or 3D. In addition, we consider the highly nonlinear scenario of a recoiling black hole produced in the merger of a supermassive black hole binary interacting with the surrounding ...
Hawking Radiation of Mass Generating Particles from Dyonic Reissner–Nordström Black Hole
Indian Academy of Sciences (India)
I. Sakalli; A Ovgun
2016-09-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton--Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyse the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton--Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner--Nordström black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed in reading the standard Hawking temperature of the dyonic Reissner–Nordström black hole.
Automated fiducial marker planning for thoracic stereotactic body radiation therapy
Gibbs, Jason D.; Rai, Lav; Wibowo, Henky; Tsalyuk, Serge; Anderson, Eric D.
2012-02-01
Stereotactic body-radiation therapy (SBRT) has gained acceptance in treating lung cancer. Localization of a thoracic lesion is challenging as tumors can move significantly with breathing. Some SBRT systems compensate for tumor motion with the intrafraction tracking of targets by two stereo fluoroscopy cameras. However, many lung tumors lack a fluoroscopic signature and cannot be directly tracked. Small radiopaque fiducial markers, acting as fluoroscopically visible surrogates, are instead implanted nearby. The spacing and configuration of the fiducial markers is important to the success of the therapy as SBRT systems impose constraints on the geometry of a fiducial-marker constellation. It is difficult even for experienced physicians mentally assess the validity of a constellation a priori. To address this challenge, we present the first automated planning system for bronchoscopic fiducial-marker placement. Fiducial-marker planning is posed as a constrained combinatoric optimization problem. Constraints include requiring access from a navigable airway, having sufficient separation in the fluoroscopic imaging planes to resolve each individual marker, and avoidance of major blood vessels. Automated fiducial-marker planning takes approximately fifteen seconds, fitting within the clinical workflow. The resulting locations are integrated into a virtual bronchoscopic planning system, which provides guidance to each location during the implantation procedure. To date, we have retrospectively planned over 50 targets for treatment, and have implanted markers according to the automated plan in one patient who then underwent SBRT treatment. To our knowledge, this approach is the first to address automated bronchoscopic fiducialmarker planning for SBRT.
Antler and Body Size in Black-Tailed Deer: An Analysis of Cohort Effects
Directory of Open Access Journals (Sweden)
Johanna C. Thalmann
2015-01-01
Full Text Available For long-lived species, environmental factors experienced early in life can have lasting effects persisting into adulthood. Large herbivores can be susceptible to cohort-wide declines in fitness as a result of decreases in forage availability, because of extrinsic factors, including extreme climate or high population densities. To examine effects of cohort-specific extrinsic factors on size of adults, we performed a retrospective analysis on harvest data of 450 male black-tailed deer (Odocoileus hemionus columbianus over 19 years in central California, USA. We determined that population density of females had a more dominant effect than did precipitation on body size of males. Harvest of female deer resulted in increases in the overall size of males, even though a 6-year drought occurred during that treatment period. Body size was most influenced by female population density early in life, while antler size was highly affected by both weather early in life and the year directly before harvest. This study provides insights that improve our understanding of the role of cohort effects in body and antler size by cervids; and, in particular, that reduction in female population density can have a profound effect on the body and antler size of male deer.
Convection in radiatively inefficient black hole accretion flows
Igumenshchev, I V; Igumenshchev, Igor V.; Abramowicz, Marek Artur
2001-01-01
Recent numerical simulations of radiatively inefficient accretion flows onto compact objects have shown that convection is a general feature in such flows. Dissipation of rotational and gravitational energies in the accretion flows results in inward increase of entropy and development of efficient convective motions. Convection-dominated accretion flows (CDAFs) have a structure that is modified significantly in comparison with the canonical advection-dominated and Bondi-like accretion flows. The flows are characterized by the flattened radial density profiles, ~R^{-1/2}, and have reduced mass accretion rates. Convection transports outward a significant amount of the released binding energy of the accretion flow. We discuss basic dynamical and observational properties of ADAFs using numerical models and self-similar analytical solutions.
Mergers of non-spinning black-hole binaries: Gravitational radiation characteristics
Baker, John G; Centrella, Joan; Kelly, Bernard J; McWilliams, Sean T; van Meter, James R
2008-01-01
We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of non-spinning black holes, based on numerical simulations of systems varying from equal-mass to a 6:1 mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an interpretation of the waveforms in terms of an {\\em implicit rotating source}. This interpretation applies uniformly to the full wavetrain, from inspiral through ringdown. We emphasize strong relationships among the $\\ell=m$ modes that persist through the full wavetrain. Exploring the structure of the waveforms in more detail, we conduct detailed analytic fitting of the late-time frequency evolution, identifying a key quantitative feature shared by the $\\ell=m$ modes among all mass-ratios. We identify relationships, with...
Generalized Uncertainty Principle in Hawking Radiation of Noncommutative Schwarzschild Black Hole
International Nuclear Information System (INIS)
The effects of noncommutativity in the framework of coordinate coherent states for Schwarzschild metric lead to a corrected solution in terms of the noncommutative parameter θ. Using the quasi-classical method, the Hawking radiation of such a noncommutative inspired black hole via the tunneling process is studied. In this situation, utilizing the generalized uncertainty principle, we show that the modification of the de Broglie relation in the quantum tunneling process of the black hole evaporation, provides the non-thermal effects which create the correlations between emitted modes of evaporation. In this setup, at least part of the quantum information becomes encoded in the Hawking radiation, and information can be appeared in the form of the non-thermal GUP correlations merged with the noncommutativity influences. (authors)
Extracting Information about the Initial State from the Black Hole Radiation.
Lochan, Kinjalk; Padmanabhan, T
2016-02-01
The crux of the black hole information paradox is related to the fact that the complete information about the initial state of a quantum field in a collapsing spacetime is not available to future asymptotic observers, belying the expectations from a unitary quantum theory. We study the imprints of the initial quantum state contained in a specific class of distortions of the black hole radiation and identify the classes of in states that can be partially or fully reconstructed from the information contained within. Even for the general in state, we can uncover some specific information. These results suggest that a classical collapse scenario ignores this richness of information in the resulting spectrum and a consistent quantum treatment of the entire collapse process might allow us to retrieve much more information from the spectrum of the final radiation.
Extracting Information about the Initial State from the Black Hole Radiation.
Lochan, Kinjalk; Padmanabhan, T
2016-02-01
The crux of the black hole information paradox is related to the fact that the complete information about the initial state of a quantum field in a collapsing spacetime is not available to future asymptotic observers, belying the expectations from a unitary quantum theory. We study the imprints of the initial quantum state contained in a specific class of distortions of the black hole radiation and identify the classes of in states that can be partially or fully reconstructed from the information contained within. Even for the general in state, we can uncover some specific information. These results suggest that a classical collapse scenario ignores this richness of information in the resulting spectrum and a consistent quantum treatment of the entire collapse process might allow us to retrieve much more information from the spectrum of the final radiation. PMID:26894699
Yuan, Ye-Fei; Huang, Lei; Shen, Zhi-Qiang
2009-01-01
In fully general relativity, we calculate the images of the radiatively inefficient accretion flow (RIAF) surrounding a Kerr black hole with arbitrary spins, inclination angles, and observational wavelengths. For the same initial conditions, such as the fixed accretion rate, it is found that the intrinsic size and radiation intensity of the images become larger, but the images become more compact in the inner region, while the size of the black hole shadow decreases with the increase of the black hole spin. With the increase of the inclination angles, the shapes of the black hole shadows change and become smaller, even disappear at all due to the obscuration by the thick disks. For median inclination angles, the radial velocity observed at infinity is larger because of both the rotation and radial motion of the fluid in the disk, which results in the luminous part of the images is much brighter. For larger inclination angles, such as the disk is edge on, the emission becomes dimmer at longer observational wav...
Cardoso, V; Cardoso, Vitor; Lemos, Jos\\'e P. S.
2003-01-01
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss possible connections between these results and the black hole-black hole collision at the speed of light process. With these results at hand, we predict that during the high speed collision of a non-rotating hole with a rotating one, about 35% of the total energy gets converted into gravitational waves. Thus, if one is able to produce black holes at the Large Hadron Collider, 35% of the partons' energy should be emitted during the so called balding phase. This energy will be missing, since we don't have gravitational wave detectors able to measure such amp...
Feng, Zhongwen; Zhu, Xiaodan; Li, Guoping; Fang, Weijing; Zu, Xiaotao
2016-01-01
Incorporating the generalized uncertainty principle (GUP) into the tunneling mechanism, we have studied the tunneling radiation of the scalar particles and fermions from the five-dimensional Schwarzschild-Tangherlini black hole. The results showed that the GUP corrected temperatures do not only depend on the mass of ST black hole, but are also affected by the gravity effects correction β. Besides, the β slows down the Hawking temperature increasing and causes the existence of remnants in black hole evaporation.
Stevenson, Stephanie Y
2012-01-01
Culturally produced dominant representations and discourses mark low-income, urban black girls’ bodies, thoughts, and actions as “fast (i.e. sexually promiscuous). This punitive label enforces regulatory systems where the girls can be policed and reprimanded. This paper closely examines political narratives, policies, ethnographic data from focus groups with urban black Baltimorean middle school girls, and online coverage of a Baltimore City teen school sex scandal. The author uses an interse...
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen; YANG Shu-Zheng
2005-01-01
@@ We extend Parikh's recent work to Schwarzchild-anti-de Sitter black hole with topological defect whose ArnowittDeser-Misner (ADM) mass is no longer identical to its mass parameter. We view the Hawking radiation as a tunnelling process across the event horizon and the cosmological horizon. From the tunnelling probability, we find a leading correction to the semi-classical emission rate. The result employs an underlying unitary theory.
Wu, S Q; Xu, Cai
2002-01-01
Quantum thermal effect of Weyl neutrinos in a rectilinearly non-uniformly accelerating Kinnersley black hole is investigated by using the generalized tortoise coordinate transformation. The equation that determines the location, the Hawking temperature of the event horizon and the thermal radiation spectrum of neutrinos are derived. Our results show that the location and the temperature of the event horizon depend not only on the time but also on the angle.
Hawking Radiation of Spin-1 Particles From Three Dimensional Rotating Hairy Black Hole
Sakalli, I
2015-01-01
In the present article, we study the Hawking radiation (HR) of spin-1 particles -- so-called vector particles -- from a three dimensional (3D) rotating black hole with scalar hair (RBHWSH) using Hamilton-Jacobi (HJ) ansatz. Putting the Proca equation amalgamated with the WKB approximation in process, the tunneling spectrum of vector particles is obtained. We recover the standard Hawking temperature corresponding to the emission of these particles from RBHWSH.
Hawking Radiation of Mass Generating Particles From Dyonic Reissner Nordstr\\"{o}m Black Hole
Sakalli, I.; Övgün, A.
2016-01-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads...
Ellis, George F. R.; Goswami, Rituparno; Hamid, Aymen I. M.; Maharaj, Sunil D.(Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag 54001, 4000, Durban, South Africa)
2014-01-01
This paper considers the nature of apparent horizons for astrophysical black hole situated in a realistic cosmological context. Using semi-tetrad covariant methods we study the local evolutions of the boundaries of the trapped region in the spacetime. For a collapsing massive star immersed in a cosmology with Cosmic Background Radiation (CBR), we show that the initial 2 dimensional marginally trapped surface bifurcates into inner and outer horizons. The inner horizon is timelike while the con...
A Monte Carlo Code for Relativistic Radiation Transport Around Kerr Black Holes
Schnittman, Jeremy David; Krolik, Julian H.
2013-01-01
We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.
Institute of Scientific and Technical Information of China (English)
吴双清; 蔡勖
2002-01-01
The quantum thermal effect of Weyl neutrinos in a rectilinearly non-uniformly accelerating Kinnersley black holeis investigated using the generalized tortoise coordinate transformation. The equations that determine the location, theHawking temperature of the event horizon and the thermal radiation spectrum of neutrinos are derived. Our resultsshow that the location and the temperature of the event horizon depend not only on the time but also on the angle.
Hawking radiation of Kerr-de Sitter black holes using Hamilton-Jacobi method
Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.
2013-05-01
Hawking radiation of Kerr-de Sitter black hole is investigated using Hamilton-Jacobi method. When the well-behaved Painleve coordinate system and Eddington coordinate are used, we get the correct result of Bekenstein-Hawking entropy before and after radiation but a direct computation will lead to a wrong result via Hamilton-Jacobi method. Our results show that the tunneling probability is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal but it is consistent with underlying unitary theory.
Remarks on Hawking radiation as tunneling from a uniformly accelerating black hole
Zeng, Xiao-Xiong; Hou, Jian-Song; Yang, Shu-Zheng
2008-03-01
Motivated by the Hamilton-Jacobi method of Angheben et al, we investigate the Hawking tunneling radiation from a uniformly accelerating rectilinear black hole for which the horizons and entropy are functions of θ. After several coordinate transformations, we conclude that when the self-gravitational interaction and energy conservation are taken into account, the actual radiation spectrum deviates from the thermal one and the tunneling rate is the function of θ though it is still related to the change of the Bekenstein-Hawking entropy.
Hawking radiation from the charged and magnetized BTZ black hole via covariant anomaly
Institute of Scientific and Technical Information of China (English)
Zeng Xiao-Xiong; Yang Shu-Zheng
2009-01-01
This paper discusses Hawking radiation from the charged and magnetized Bafiados-Teitelboim-Zanelli (BTZ) black hole from the viewpoint of anomaly, initiated by Robinson and Wilczek recently. It reconstructs the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges to redefine an equivalent charge and gauge potential. It employs the covariant anomaly cancellation method to determine thecompensating fluxes of charge flow and energy-momentum tensor, which are shown to match with those of the 2- dimensional blackbody radiation at the Hawking temperature exactly.
Tunnelling Radiation of Charged and Magnetized Massive Particles from BTZ Black Holes
Institute of Scientific and Technical Information of China (English)
HE Tang-Mei; ZHANG Jing-Yi
2007-01-01
We investigate the tunnelling radiation of charged and magnetized massive particles from a Ba(n)ados-TeitelboimZanelli (BTZ) black hole by extending the Parikh-Wilczek tunnelling framework. In order to calculate the emission rate,we reconstruct the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges,and treat the charges as an equivalent electric charge for simplicity in the later calculation.The result supports Parikh-Wilczek's conclusion,that is,the Hawking thermal radiation actually deviates from perfect thermality and agrees with an underlying unitary theory.
Black hole radiation of massive spin-2 particles in (3+1) dimensions
Sakalli, I.; Ovgun, A.
2016-01-01
This paper is devoted to the study of radiation of massive spin-2 boson (graviton with a nonzero mass) through the event horizon of a generic static and spherically symmetric black hole in (3+1) dimensions. To this end, we consider the problem in the framework of quantum tunneling phenomenon. We evaluate the tunneling rate of the massive gravitons by applying the semiclassical WKB approximation to the Fierz-Pauli equation. The temperature of the radiation is obtained with the aid of the Boltz...
Remarks on Hawking radiation as tunneling from a uniformly accelerating black hole
Indian Academy of Sciences (India)
Xiao-Xiong Zeng; Jian-Song Hou; Shu-Zheng Yang
2008-03-01
Motivated by the Hamilton-Jacobi method of Angheben et al, we investigate the Hawking tunneling radiation from a uniformly accelerating rectilinear black hole for which the horizons and entropy are functions of . After several coordinate transformations, we conclude that when the self-gravitational interaction and energy conservation are taken into account, the actual radiation spectrum deviates from the thermal one and the tunneling rate is the function of though it is still related to the change of the Bekenstein-Hawking entropy.
International Nuclear Information System (INIS)
Following on after two previous papers discussing the formation of primordial black holes in the early universe, we present here results from an in-depth investigation of the extent to which primordial black hole formation in the radiative era can be considered as an example of the critical collapse phenomenon. We focus on initial supra-horizon-scale perturbations of a type which could have come from inflation, with only a growing component and no decaying component. In order to study perturbations with amplitudes extremely close to the supposed critical limit, we have modified our previous computer code with the introduction of an adaptive mesh refinement scheme. This has allowed us to follow black hole formation from perturbations whose amplitudes are up to eight orders of magnitude closer to the threshold than we could do before. We find that scaling-law behaviour continues down to the smallest black hole masses that we are able to follow and we see no evidence of shock production such as has been reported in some previous studies and which led there to a breaking of the scaling-law behaviour at small black hole masses. We attribute this difference to the different initial conditions used. In addition to the scaling law, we also present other features of the results which are characteristic of critical collapse in this context.
Ghosh, Debjani; Pal, Sandip; Saha, Chabita; Chakrabarti, Amit Kumar; Datta, Salil C; Dey, Subrata Kumar
2012-01-01
Myriad research has contributed significantly toward the understanding and identification of health benefits stemming from tea polyphenols and many other naturally occurring flavonoids present in fruits and vegetables. These flavonoids are known to mitigate reactive oxygen species-induced damage by scavenging them. In this study, hot-water black tea extract rich in flavonoids is evaluated as a supplementary antioxidant. The antioxidant efficacy of black tea extract was investigated by evaluating radioprotection conferred to pBR322 DNA, calf thymus DNA, and normal lymphocytes during gamma irradiation. The protection was measured by gel electrophoresis, fluorimetric study, cell viability assay, cytokinesis-blocked micronuclei assay, and comet assay. The 2,2-diphenyl-1-picrylhydrazyl scavenging ability of the tea extract used increased in a dose-dependent manner (IC50: 182.45 µg/mL). Positive correlation of radioprotection with antioxidant activity of black tea extract was observed in all systems. Maximum protection against radiation-induced damage was observed in pBR322 DNA and calf thymus DNA at ≥200 µg/mL of black tea extract. At a dose of black tea extract as low as 5 µg/mL, efficient radioprotection was observed in normal lymphocytes, which is encouraging and can be tested in the future as a natural antioxidant supplement during radiotherapy.
“My Body the Lesson”: Queering Black Women’s Subjectivities in The Street and Symptomatic
Quinn, Rachel Afi
2008-01-01
As twentieth-century black women writers, Ann Petry and Danzy Senna have used the form of the novel to construct multifaceted black women’s subjectivities through what Mae Henderson refers to as “simultaneity of discourse”. By including characters in their novels that inhabit non-normative bodies, both Petry with The Street(1946) and Senna with Symptomatic(2004) expand our notions of what it means to be female and black. This paper will theorize the “queer of color” identities of two particu...
BLACK HOLE FORMATION IN PRIMORDIAL GALAXIES: CHEMICAL AND RADIATIVE CONDITIONS
International Nuclear Information System (INIS)
In massive primordial galaxies, the gas may directly collapse and form a single central massive object if cooling is suppressed. H2 line cooling can be suppressed in the presence of a strong soft-ultraviolet radiation field, but the role played by other cooling mechanisms is less clear. In optically thin gas, Lyα cooling can be very effective, maintaining the gas temperature below 104 K over many orders of magnitude in density. However, the large neutral hydrogen column densities present in primordial galaxies render them highly optically thick to Lyα photons. In this paper, we examine in detail the effects of the trapping of these Lyα photons on the thermal and chemical evolution of the gas. We show that despite the high optical depth in the Lyman series lines, cooling is not strongly suppressed, and proceeds via other atomic hydrogen transitions. At densities larger than ∼109 cm-3, collisional dissociation of molecular hydrogen becomes the dominant cooling process and decreases the gas temperature to about 5000 K. The gas temperature evolves with density as T∝ργeff-1, with γeff = 0.97-0.98. The evolution is thus very close to isothermal, and so fragmentation is possible, but unlikely to occur during the initial collapse. However, after the formation of a massive central object, we expect that later-infalling, higher angular momentum material will form an accretion disk that may be unstable to fragmentation, which may give rise to star formation with a top-heavy initial mass function.
Stereotactic body radiation therapy for centrally located lung lesions
Energy Technology Data Exchange (ETDEWEB)
Joyner, Melissa [Univ. of Texas Health Science Center at San Antonio (United States). Dept. of Radiation Oncology; Salter, Bill J. [The Univ. of Utah, Salt Lake City, Utah (United States). Dept. of Radiation Oncology; Papanikolaou, Niko [Cancer Therapy and Research Center, San Antonio, Texas (United States); Fuss, Martin [Oregon Health and Science Univ., Portland (United States). Dept. of Radiation Medicine
2006-09-15
Presentation of outcomes of patients treated by stereotactic body radiation therapy (SBRT) for lung lesions located within or touching a 2 cm zone around major airways. Serial tomotherapeutic SBRT has been planned and delivered at our institution since August 2001. Of 108 patients treated for primary and secondary lung tumors, nine harbored tumors (8 metastases, 1 recurrent NSCLC) located in close proximity to carina, right and left main bronchi, right and left upper lobe bronchi, intermedius, right middle lobe, lingular, or right and left lower lobe bronchi. SBRT was delivered to total doses of 36 Gy in 3 fractions (n=8) or 6 fractions (n=1), using a serial tomotherapy system (Nomos Peacock). We assessed local tumor control, clinical toxicity, normal tissue imaging changes, and overall survival. Median tumor volume was 26 cm{sup 3} (range 1.7 to 135 cm{sup 3}). Tumor locations were hilar (n=3), and parenchymal in six cases. Hilar lesions accounted for the three largest tumor volumes in the series. During a median follow-up of 10.6 months (range 2.5 to 41.5 months), all lesions treated were locally controlled as confirmed by CT or CT/PET imaging. Parenchymal imaging changes included focal lung fibrosis and major airway wall thickening. One occurrence of major airway occlusion (right lower lobe bronchus) was observed. This event was diagnosed by chest x-ray at 36 months, following treatment of the second largest hilar lesion in the present series. Based on the outcomes observed in this small sample series, SBRT for centrally located lung lesions appears feasible, was associated with low incidence of toxicities, and provided sustained local tumor control. However, long-term survival may be associated with major airway injury. As long-term follow-up in larger numbers of patients is lacking at this time, exclusion of patients with centrally located lesions may be considered when patients are treated in curative intent.
Stereotactic Body Radiation Therapy in Recurrent Hepatocellular Carcinoma
Energy Technology Data Exchange (ETDEWEB)
Huang, Wen-Yen [Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (China); Jen, Yee-Min, E-mail: yeeminjen@yahoo.com.tw [Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (China); Lee, Meei-Shyuan [School of Public Health, National Defense Medical Center, Taipei, Taiwan (China); Chang, Li-Ping [Department of Radiation Oncology, Cardinal Tien Hospital, Taipei, Taiwan (China); Chen, Chang-Ming [Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (China); Ko, Kai-Hsiung [Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (China); Lin, Kuen-Tze; Lin, Jang-Chun; Chao, Hsing-Lung; Lin, Chun-Shu; Su, Yu-Fu; Fan, Chao-Yueh; Chang, Yao-Wen [Department of Radiation Oncology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (China)
2012-10-01
Purpose: To examine the safety and efficacy of Cyberknife stereotactic body radiation therapy (SBRT) and its effect on survival in patients of recurrent hepatocellular carcinoma (HCC). Methods and Materials: This was a matched-pair study. From January 2008 to December 2009, 36 patients with 42 lesions of unresectable recurrent HCC were treated with SBRT. The median prescribed dose was 37 Gy (range, 25 to 48 Gy) in 4-5 fractions over 4-5 consecutive working days. Another 138 patients in the historical control group given other or no treatments were selected for matched analyses. Results: The median follow-up time was 14 months for all patients and 20 months for those alive. The 1- and 2-year in-field failure-free rates were 87.6% and 75.1%, respectively. Out-field intrahepatic recurrence was the main cause of failure. The 2-year overall survival (OS) rate was 64.0%, and median time to progression was 8.0 months. In the multivariable analysis of all 174 patients, SBRT (yes vs. no), tumor size ({<=}4 cm vs. >4 cm), recurrent stage (stage IIIB/IV vs. I) and Child-Pugh classification (A vs. B/C) were independent prognostic factors for OS. Matched-pair analysis revealed that patients undergoing SBRT had better OS (2-year OS of 72.6% vs. 42.1%, respectively, p = 0.013). Acute toxicities were mild and tolerable. Conclusion: SBRT is a safe and efficacious modality and appears to be well-tolerated at the dose fractionation we have used, and its use correlates with improved survival in this cohort of patients with recurrent unresectable HCC. Out-field recurrence is the major cause of failure. Further studies of combinations of SBRT and systemic therapies may be reasonable.
Small Bowel Dose Tolerance for Stereotactic Body Radiation Therapy.
LaCouture, Tamara A; Xue, Jinyu; Subedi, Gopal; Xu, Qianyi; Lee, Justin T; Kubicek, Gregory; Asbell, Sucha O
2016-04-01
Inconsistencies permeate the literature regarding small bowel dose tolerance limits for stereotactic body radiation therapy (SBRT) treatments. In this review, we organized these diverse published limits with MD Anderson at Cooper data into a unified framework, constructing the dose-volume histogram (DVH) Risk Map, demonstrating low-risk and high-risk SBRT dose tolerance limits for small bowel. Statistical models of clinical data from 2 institutions were used to assess the safety spectrum of doses used in the exposure of the gastrointestinal tract in SBRT; 30% of the analyzed cases had vascular endothelial growth factor inhibitors (VEGFI) or other biological agents within 2 years before or after SBRT. For every dose tolerance limit in the DVH Risk Map, the probit dose-response model was used to estimate the risk level from our clinical data. Using the current literature, 21Gy to 5cc of small bowel in 3 fractions has low toxicity and is reasonably safe, with 6.5% estimated risk of grade 3 or higher complications, per Common Terminology Criteria for Adverse Events version 4.0. In the same fractionation for the same volume, if lower risk is required, 16.2Gy has an estimated risk of only 2.5%. Other volumes and fractionations are also reviewed; for all analyzed high-risk small bowel limits, the risk is 8.2% or less, and the low-risk limits have 4% or lower estimated risk. The results support current clinical practice, with some possibility for dose escalation. PMID:27000513
Implications of multiple scattering on the assessment of black carbon aerosol radiative forcing
International Nuclear Information System (INIS)
The effects of radiative coupling between scattering and absorbing aerosols, in an external mixture, on the aerosol radiative forcing (ARF) due to black carbon (BC), its sensitivity to the composite aerosol loading and composition, and surface reflectance are investigated using radiative transfer model simulations. The ARF due to BC is found to depend significantly on the optical properties of the ‘neighboring’ (non-BC) aerosol species. The scattering due to these species significantly increases the top of the atmospheric warming due to black carbon aerosols, and significant changes in the radiative forcing efficiency of BC. This is especially significant over dark surfaces (such as oceans), despite the ARF due to BC being higher over snow and land-surfaces. The spatial heterogeneity of this effect (coupling or multiple scattering by neighboring aerosol species) imposes large uncertainty in the estimation ARF due to BC aerosols, especially over the oceans. - Highlights: • Non-BC aerosol scattering in an external mixture increases TOA warming due to BC. • Effect of multiple scattering on BC ARF increases with total aerosol optical depth. • Contribution of multiple scattering on BC ARF is higher over oceans than over land
Lan, Xiao-Gang
2013-05-01
By introducing a new tortoise coordinate transformation, we apply Damour-Ruffini-Sannan method to study the Hawking radiation of massive scalar particles in a dynamic Dilaton-Maxwell black hole. We find that Hawking radiation spectrum shows still the blackbody one, while the Hawking temperature is significantly changed. Additionally, by adopting the thin film method, we calculate the entropy of a dynamic Dilaton-Maxwell black hole. The result indicates that the entropy for such a black hole is still in proportional to the area of its event horizon.
Liang, Jun; Zhang, Fang-Hui; Zhang, Wei; Zhang, Jing
2014-01-01
By utilizing the improved Damour-Ruffini method with a new tortoise transformation, we study the Hawking radiation of Dirac particles from a general dynamical spherically symmetric black hole. In the improved Damour-Ruffini method, the position of the event horizon of the black hole is an undetermined function, and the temperature parameter κ is an undetermined constant. By requiring the Dirac equation to be the standard wave equation near the event horizon of the black hole, κ can be determined automatically. Therefore, the Hawking temperature can be obtained. The result is consistent with that of the Hawking radiation of scalar particles.
Hossain, M Ilias
2013-01-01
Incorporating Parikh and Wilczek's opinion to the Kerr de-Sitter (KdS) black hole Hawking non-thermal and purely thermal radiations have been investigated using Hamilton-Jacobi method. We have taken the background spacetime of KdS black hole as dynamical, involving the self-gravitation effect of the emitted particles, energy and angular momentum has been taken as conserved and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The explored results gives a correction to the Hawking radiation of KdS black hole.
Chen, Lingshen
2016-01-01
The Parikh-Kraus-Wilczeck tunneling radiation of black hole involving a $f(R)$ global monopole is considered based on the generalized uncertainty principle. The influences from global monopole, $f(R)$ gravity and the corrections to the uncertainty appear in the expression of black hole entropy difference. It is found that the global monopole and the revision of general relativity both hinder the black hole from emitting the photons. The two parts as corrections to the uncertainty make the entropy difference of this kind of black hole larger or smaller respectively.
The high frequency acoustic radiation from the boundary layer of an axisymmetric body
Institute of Scientific and Technical Information of China (English)
LI Fuxin; MA Lin; MA Zhiming
2001-01-01
The mechanism of acoustic radiation from the boundary layer of an axisymmetric body is analyzed, and its sound pressure spectrum is predicted. It is shown that the acoustic radiation results from the transition region and the turbulent boundary layer; and that the acoustic radiation from transition region is predominant at low frequencies; while the turbulent boundary layer has the decisive effect on acoustic radiation at high frequencies. The calculated values are in good agreement with the experimental data.
Radiobiological mechanisms of stereotactic body radiation therapy and stereotactic radiation surgery
Energy Technology Data Exchange (ETDEWEB)
Kim, Mi Sook; Kim, Won Woo; Park, In Hwan; Kim, Hee Jong; Lee, Eun Jin; Jung, Jae Hoon [Research Center for Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Cho, Lawrence Chin Soo; Song, Chang W. [Dept. of Radiation Oncology, University of Minnesota Medical School, Minneapolis (United States)
2015-12-15
Despite the increasing use of stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS) in recent years, the biological base of these high-dose hypo-fractionated radiotherapy modalities has been elusive. Given that most human tumors contain radioresistant hypoxic tumor cells, the radiobiological principles for the conventional multiple-fractionated radiotherapy cannot account for the high efficacy of SBRT and SRS. Recent emerging evidence strongly indicates that SBRT and SRS not only directly kill tumor cells, but also destroy the tumor vascular beds, thereby deteriorating intratumor microenvironment leading to indirect tumor cell death. Furthermore, indications are that the massive release of tumor antigens from the tumor cells directly and indirectly killed by SBRT and SRS stimulate anti-tumor immunity, thereby suppressing recurrence and metastatic tumor growth. The reoxygenation, repair, repopulation, and redistribution, which are important components in the response of tumors to conventional fractionated radiotherapy, play relatively little role in SBRT and SRS. The linear-quadratic model, which accounts for only direct cell death has been suggested to overestimate the cell death by high dose per fraction irradiation. However, the model may in some clinical cases incidentally do not overestimate total cell death because high-dose irradiation causes additional cell death through indirect mechanisms. For the improvement of the efficacy of SBRT and SRS, further investigation is warranted to gain detailed insights into the mechanisms underlying the SBRT and SRS.
A public code for general relativistic, polarised radiative transfer around spinning black holes
Dexter, Jason
2016-01-01
Ray tracing radiative transfer is a powerful method for comparing theoretical models of black hole accretion flows and jets with observations. We present a public code, grtrans, for carrying out such calculations in the Kerr metric, including the full treatment of polarised radiative transfer and parallel transport along geodesics. The code is written in Fortran 90 and efficiently parallelises with OpenMP, and the full code and several components have Python interfaces. We describe several tests which are used for verifiying the code, and we compare the results for polarised thin accretion disc and semi-analytic jet problems with those from the literature as examples of its use. Along the way, we provide accurate fitting functions for polarised synchrotron emission and transfer coefficients from thermal and power law distribution functions, and compare results from numerical integration and quadrature solutions of the polarised radiative transfer equations. We also show that all transfer coefficients can play...
Body adiposity indices are associated with hypertension in a black, urban Free State community
Directory of Open Access Journals (Sweden)
Ronette Lategan
2014-01-01
Full Text Available Background: Non-communicable diseases, including hypertension, are increasing rapidly in resource-poor, developing countries amongst populations transitioning from traditional to westernised lifestyles; and are associated with excess weight.Aim: To investigate the relationship between hypertension and various indices of body adiposity in a transitioning, urban, black population.Setting: Three hundred and thirty-nine adults (25–64 years from a larger cross-sectional study (Assuring Health for All in the Free State conducted in Mangaung, South Africa, were included.Methods: Standard techniques were used to determine blood pressure, HIV status, body mass index (BMI, waist-to-height ratio (WHtR and body adiposity index (BAI.Results: Approximately 40% of the sample was HIV-positive and 63.4% hypertensive, with the greatest risk of hypertension being amongst older men. Based on BMI, 23.0% were overweight and 32.1% obese. Waist-to-height ratio showed that 58.6% had increased cardiovascular risk. Mean BAI was 34.1%, whilst 76.3% had a body fat percentage in the overweight/obese category. Waist circumference representing increased cardiovascular risk was found in 44.3% of women and 3.9% of men. Significant positive correlations between mean arterial bloodpressure and BMI (r = 0.261; p < 0.001, WHtR (r = 0.357; p < 0.001 and BAI (r = 0.245; p <0.001 were found. WHtR was a stronger predictor of mean arterial pressure than BMI or BAI. HIV status showed an inverse correlation with all adiposity indices (p < 0.001.Conclusion: Our findings promote WHtR as a practical screening tool for increased hypertension risk in populations undergoing westernisation, and support weight loss as afirst-line intervention for the prevention and management of hypertension.
Body adiposity indices are associated with hypertension in a black, urban Free State community
Directory of Open Access Journals (Sweden)
Ronette Lategan
2014-05-01
Full Text Available Background: Non-communicable diseases, including hypertension, are increasing rapidly in resource-poor, developing countries amongst populations transitioning from traditional to westernised lifestyles; and are associated with excess weight. Aim: To investigate the relationship between hypertension and various indices of body adiposity in a transitioning, urban, black population. Setting: Three hundred and thirty-nine adults (25–64 years from a larger cross-sectional study (Assuring Health for All in the Free State conducted in Mangaung, South Africa, were included. Methods: Standard techniques were used to determine blood pressure, HIV status, body mass index (BMI, waist-to-height ratio (WHtR and body adiposity index (BAI. Results: Approximately 40% of the sample was HIV-positive and 63.4% hypertensive, with the greatest risk of hypertension being amongst older men. Based on BMI, 23.0% were overweight and 32.1% obese. Waist-to-height ratio showed that 58.6% had increased cardiovascular risk. Mean BAI was 34.1%, whilst 76.3% had a body fat percentage in the overweight/obese category. Waist circumference representing increased cardiovascular risk was found in 44.3% of women and 3.9% of men. Significant positive correlations between mean arterial blood pressure and BMI (r = 0.261; p < 0.001, WHtR (r = 0.357; p < 0.001 and BAI (r = 0.245; p < 0.001 were found. WHtR was a stronger predictor of mean arterial pressure than BMI or BAI. HIV status showed an inverse correlation with all adiposity indices (p < 0.001. Conclusion: Our findings promote WHtR as a practical screening tool for increased hypertension risk in populations undergoing westernisation, and support weight loss as a first-line intervention for the prevention and management of hypertension.
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Static Frame
Wang, Peng
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the Hawking's prediction, the dispersive field theory models have been proposed, following the Unruh's hydrodynamic analogue of a black hole radiation. In the dispersive field theory models, the dispersion relations of matter fields are modified at high energies, which leads to modifications of equations of motion. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass $m_{p}$. We calculate the corrections to the Hawking temperature for massive and charged particles to $\\mathcal{O}\\left(m_{p}^{-2}\\right) $ and massless and neutral particles to all orders. Our res...
Lommen, A N; Lommen, Andrea N.; Backer, Donald C.
2001-01-01
Pulsar timing measurements can be used to detect gravitational radiation from massive black hole binaries. The ~106d quasi-periodic flux variations in Sagittarius A* at radio wavelengths reported by Zhao, Bower, & Goss (2001) may be due to binarity of the massive black hole that is presumed to be responsible for the radio emission. A 106d equal-mass binary black hole is unlikely based on its short inspiral lifetime and other arguments. Nevertheless the reported quasi-periodicity has led us to consider whether the long-wavelength gravitational waves from a conjectured binary might be detected in present or future precision timing of millisecond pulsars. While present timing cannot reach the level expected for an equal-mass binary, we estimate that future efforts could. This inquiry has led us to further consider the detection of binarity in the massive black holes now being found in nearby galaxies. For orbital periods of ~2000d where the pulsar timing measurements are most precise, we place upper limits o...
Hod, Shahar
2016-01-01
It has recently been suggested [S. B. Giddings, Phys. Lett. B {\\bf 754}, 39 (2016)] that the Hawking black-hole radiation spectrum originates from an effective quantum "atmosphere" which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a $(3+1)$-dimensional Schwarzschild black hole of horizon radius $r_{\\text{H}}$ with the familiar Stefan-Boltzmann radiation power of a $(3+1)$-dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi-classical black-hole radiation is a quantum region outside the Schwarzschild black-hole horizon whose effective radius $r_{\\text{A}}$ is characterized by the relation $\\Delta r\\equiv r_{\\text{A}}-r_{\\text{H}}\\sim r_{\\text{H}}$. It is of considerable physical interest to test the general validity of Giddings's intriguing conclusion. To this end, we study the Hawking radiation of $(D+1)$-dimensional Schwarzschild black holes. We find that the dimensionless radii $r_{\\text{A}}/r_{\\text...
Adaptive Stereotactic Body Radiation Therapy Planning for Lung Cancer
Energy Technology Data Exchange (ETDEWEB)
Qin, Yujiao [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Zhang, Fan [Occupational and Environmental Safety Office, Duke University Medical Center, Durham, North Carolina (United States); Yoo, David S.; Kelsey, Chris R. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Yin, Fang-Fang [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Cai, Jing, E-mail: jing.cai@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)
2013-09-01
Purpose: To investigate the dosimetric effects of adaptive planning on lung stereotactic body radiation therapy (SBRT). Methods and Materials: Forty of 66 consecutive lung SBRT patients were selected for a retrospective adaptive planning study. CBCT images acquired at each fraction were used for treatment planning. Adaptive plans were created using the same planning parameters as the original CT-based plan, with the goal to achieve comparable comformality index (CI). For each patient, 2 cumulative plans, nonadaptive plan (P{sub NON}) and adaptive plan (P{sub ADP}), were generated and compared for the following organs-at-risks (OARs): cord, esophagus, chest wall, and the lungs. Dosimetric comparison was performed between P{sub NON} and P{sub ADP} for all 40 patients. Correlations were evaluated between changes in dosimetric metrics induced by adaptive planning and potential impacting factors, including tumor-to-OAR distances (d{sub T-OAR}), initial internal target volume (ITV{sub 1}), ITV change (ΔITV), and effective ITV diameter change (Δd{sub ITV}). Results: 34 (85%) patients showed ITV decrease and 6 (15%) patients showed ITV increase throughout the course of lung SBRT. Percentage ITV change ranged from −59.6% to 13.0%, with a mean (±SD) of −21.0% (±21.4%). On average of all patients, P{sub ADP} resulted in significantly (P=0 to .045) lower values for all dosimetric metrics. Δd{sub ITV}/d{sub T-OAR} was found to correlate with changes in dose to 5 cc (ΔD5cc) of esophagus (r=0.61) and dose to 30 cc (ΔD30cc) of chest wall (r=0.81). Stronger correlations between Δd{sub ITV}/d{sub T-OAR} and ΔD30cc of chest wall were discovered for peripheral (r=0.81) and central (r=0.84) tumors, respectively. Conclusions: Dosimetric effects of adaptive lung SBRT planning depend upon target volume changes and tumor-to-OAR distances. Adaptive lung SBRT can potentially reduce dose to adjacent OARs if patients present large tumor volume shrinkage during the treatment.
Sri Rachma, Aprilita Bugiwati
2008-01-01
The present research aims to estimate the mathematical equations for predicting ultrasonic estimates of carcass traits at ten months after performance test (about 20 months of age) using body measurements and ultrasonic estimates of carcass traits at earlier stages of performance test of Japanese Black bulls. This research was done at Kagoshima and Miyazaki prefecture Livestock Experimental Stations Japan to collect the ultrasonic estimates of carcass traits and body measurements data of Jap...
Directory of Open Access Journals (Sweden)
Kelly L Robertson
Full Text Available Observations of enhanced growth of melanized fungi under low-dose ionizing radiation in the laboratory and in the damaged Chernobyl nuclear reactor suggest they have adapted the ability to survive or even benefit from exposure to ionizing radiation. However, the cellular and molecular mechanism of fungal responses to such radiation remains poorly understood. Using the black yeast Wangiella dermatitidis as a model, we confirmed that ionizing radiation enhanced cell growth by increasing cell division and cell size. Using RNA-seq technology, we compared the transcriptomic profiles of the wild type and the melanin-deficient wdpks1 mutant under irradiation and non-irradiation conditions. It was found that more than 3000 genes were differentially expressed when these two strains were constantly exposed to a low dose of ionizing radiation and that half were regulated at least two fold in either direction. Functional analysis indicated that many genes for amino acid and carbohydrate metabolism and cell cycle progression were down-regulated and that a number of antioxidant genes and genes affecting membrane fluidity were up-regulated in both irradiated strains. However, the expression of ribosomal biogenesis genes was significantly up-regulated in the irradiated wild-type strain but not in the irradiated wdpks1 mutant, implying that melanin might help to contribute radiation energy for protein translation. Furthermore, we demonstrated that long-term exposure to low doses of radiation significantly increased survivability of both the wild-type and the wdpks1 mutant, which was correlated with reduced levels of reactive oxygen species (ROS, increased production of carotenoid and induced expression of genes encoding translesion DNA synthesis. Our results represent the first functional genomic study of how melanized fungal cells respond to low dose ionizing radiation and provide clues for the identification of biological processes, molecular pathways and
Directory of Open Access Journals (Sweden)
Nutan Singh
2013-11-01
Full Text Available This paper deals with the stability of triangular Lagrangian points in the elliptical restricted three body problem, under the effect of radiation pressure stemming from the more massive primary on the infinitesimal. We adopted a set of rotating pulsating axes centered at the centre of mass of the two primaries Sun and Jupiter. We have exploited method of averaging used by Grebenikov, throughout the analysis of stability of the system. The critical mass ratio depends on the radiation pressure, eccentricity and the range of stability decreases as the radiation parameter increases. Keywords: Dynamical system, elliptical restricted three body problems, lagrangian points, radiation pressure, and stability.
Khuri, Marcus A
2015-01-01
A universal inequality that bounds the charge of a body by its size is presented, and is proven as a consequence of the Einstein equations in the context of initial data sets which satisfy an appropriate energy condition. We also present a general sufficient condition for the formation of black holes due to concentration of charge, and discuss the physical relevance of these results.
Extremal energy shifts of radiation from a ring near a rotating black hole
Karas, Vladimir
2010-01-01
Radiation from a narrow circular ring shows a characteristic double-horn profile dominated by photons having energy around the maximum or minimum of the allowed range, i.e. near the extremal values of the energy shift. The energy span of a spectral line is a function of the ring radius, black hole spin, and observer's view angle. We describe a useful approach to calculate the extremal energy shifts in the regime of strong gravity. Then we consider an accretion disk consisting of a number of separate nested annuli in the equatorial plane of Kerr black hole, above the innermost stable circular orbit (ISCO). We suggest that the radial structure of the disk emission could be reconstructed using the extremal energy shifts of the individual rings deduced from the broad wings of a relativistic spectral line.
Ultra-low frequency gravitational radiation from massive black hole binaries
Rajagopal, M; Rajagopal, Mohan; Romani, Roger W
1994-01-01
For massive black hole binaries produced in galactic mergers, we examine the possibility of inspiral induced by interaction with field stars. We model the evolution of such binaries for a range of galaxy core and binary parameters, using numerical results from the literature to compute the binary's energy and angular momentum loss rates due to stellar encounters and including the effect of back-action on the field stars. We find that only a small fraction of binary systems can merge within a Hubble time via unassisted stellar dynamics. External perturbations may, however, cause efficient inspiral. Averaging over a population of central black holes and galaxy mergers, we compute the expected background of gravitational radiation with periods Pw ~1-10y. Comparison with sensitivities from millisecond pulsar timing suggests that the strongest sources may be detectable with modest improvements to present experiments.
Shiokawa, Hotaka
The goal of the series of studies in this thesis is to understand the black hole accretion process and predict its observational properties. The highly non-linear process involves a turbulent magnetized plasma in a general relativistic regime, thus making it hard to study analytically. We use numerical simulations, specifically general relativistic magnetohydrodynamics (GRMHD), to construct a realistic dynamical and radiation model of accretion disks. Our simulations are for black holes in low luminous regimes that probably possesses a hot and thick accretion disk. Flows in this regime are called radiatively inefficient accretion flows (RIAF). The most plausible mechanism for transporting angular momentum is turbulence induced by magnetorotational instability (MRI). The RIAF model has been used to model the supermassive black hole at the center of our Milky Way galaxy, Sagittarius A* (Sgr A*). Owing to its proximity, rich observational data of Sgr A* is available to compare with the simulation results. We focus mainly on four topics. First, we analyse numerical convergence of 3D GRMHD global disk simulations. Convergence is one of the essential factors in deciding quantitative outcomes of the simulations. We analyzed dimensionless shell-averaged quantities such as plasma beta, the azimuthal correlation length (angle) of fluid variables, and spectra of the source for four different resolutions. We found that all the variables converged with the highest resolution (384x384x256 in radial, poloidal, and azimuthal directions) except the magnetic field correlation length. It probably requires another factor of 2 in resolution to achieve convergence. Second, we studied the effect of equation of state on dynamics of GRMHD simulation and radiative transfer. Temperature of RIAF gas is high, and all the electrons are relativistic, but not the ions. In addition, the dynamical time scale of the accretion disk is shorter than the collisional time scale of electrons and ions
Saganti, P. B.; Zapp, E. N.; Wilson, J. W.; Cucinotta, F. A.
2001-01-01
The US Lab module of the International Space Station (ISS) is a primary working area where the crewmembers are expected to spend majority of their time. Because of the directionality of radiation fields caused by the Earth shadow, trapped radiation pitch angle distribution, and inherent variations in the ISS shielding, a model is needed to account for these local variations in the radiation distribution. We present the calculated radiation dose (rem/yr) values for over 3,000 different points in the working area of the Lab module and estimated radiation dose values for over 25,000 different points in the human body for a given ambient radiation environment. These estimated radiation dose values are presented in a three dimensional animated interactive visualization format. Such interactive animated visualization of the radiation distribution can be generated in near real-time to track changes in the radiation environment during the orbit precession of the ISS.
A public code for general relativistic, polarised radiative transfer around spinning black holes
Dexter, Jason
2016-10-01
Ray tracing radiative transfer is a powerful method for comparing theoretical models of black hole accretion flows and jets with observations. We present a public code, GRTRANS, for carrying out such calculations in the Kerr metric, including the full treatment of polarised radiative transfer and parallel transport along geodesics. The code is written in FORTRAN 90 and efficiently parallelises with OPENMP, and the full code and several components have PYTHON interfaces. We describe several tests which are used for verifiying the code, and we compare the results for polarised thin accretion disc and semi-analytic jet problems with those from the literature as examples of its use. Along the way, we provide accurate fitting functions for polarised synchrotron emission and transfer coefficients from thermal and power-law distribution functions, and compare results from numerical integration and quadrature solutions of the polarised radiative transfer equations. We also show that all transfer coefficients can play an important role in predicted images and polarisation maps of the Galactic centre black hole, Sgr A*, at submillimetre wavelengths.
The role of Compton heating on radiation-regulated accretion on to black holes
Park, KwangHo; Di Matteo, Tiziana; Reynolds, Christopher S
2014-01-01
We investigate the role of Compton heating in radiation-regulated accretion on to black holes from a neutral dense medium using 1D radiation-hydrodynamic simulations. We focus on the relative effects of Compton-heating and photo-heating as a function of the spectral slope {\\alpha}, assuming a power-law spectrum in the energy range of 13.6 eV--100 keV. While Compton heating is dominant only close to the black hole, it can reduce the accretion rate to 0.1 % ($l \\propto \\dot{m}^2$ model)--0.01 % ($l \\propto \\dot{m}$ model) of the Bondi accretion rate when the BH radiation is hard ({\\alpha} ~ 1), where $l$ and $\\dot{m}$ are the luminosity and accretion rate normalised by Eddington rates, respectively. The oscillatory behaviour otherwise typically seen in simulations with {\\alpha} > 1, become suppressed when {\\alpha} ~ 1 only for the $l \\propto \\dot{m}$ model. The relative importance of the Compton heating over photo-heating decreases and the oscillatory behaviour becomes stronger as the spectrum softens. When the...
[Effect of ionizing radiation on the living body].
Kojima, Shuji
2014-01-01
Since the Fukushima nuclear plant accident following the great East Japan earthquake on March 11, 2011, we have been warned to be careful about possible radiation exposure almost every day in newspapers and on TV. Radioactive iodine ((131)I) and cesium ((134)Cs, (137)Cs) produced by nuclear reactions were released into the air during and after the accident, and have been scattered by the winds in Tohoku and in the Kanto district. Even today, 2 years after the accident, there is great public concern about possible pollution of foodstuffs and fishery products with radioactive cesium, not only in Japan, but also in other countries. On the other hand, decontamination work has been proceeding, including removal of contaminated soil near the accident site. Since the accident, many media reports have continued to tell us only that current dose levels of radiation are not dangerous to human health. But, many people are not satisfied with such vague statements, and want to understand the situation in more detail. So, it is important to provide basic education about the effects of radiation to the general public. I am a professor of the Department of Radiation Biosciences at Tokyo University of Science, and so I am very familiar with radiation and its dangers. So, in my lecture today, we would like to explain the effects of radiation and put the present situation into perspective, so that people will better understand the risks, and not be unnecessarily afraid.
Nagatani, Y
2001-01-01
A spherical domain wall around a small black hole is formed by the Hawking radiation from the black hole in the symmetry-broken-phase of the field theory, e.g., the Standard Model (SM) and the Grand Unified Theory (GUT) which have a property of the phase transition. We have obtained two types of the spherical domain wall; (a) thermalized wall which is formed by the local heating up near black hole and symmetry restore locally and (b) dynamical wall which is formed by the balance between the pressure from the Hawking radiation and the pressure from the wall tensions. The electroweak wall is formed as a thermalized wall around a black hole with mass of the several hundred kilogram. The GUT wall is formed as a dynamical wall around much smaller black hole. The electroweak wall around a black hole can produce baryon number by the assumption of the CP-broken phase in the wall. The GUT wall can supply charge into the black hole, namely, the wall causes the spontaneous charging up of the black hole. We propose a cos...
Energy Technology Data Exchange (ETDEWEB)
Sahgal, Arjun, E-mail: arjun.sahgal@rmp.uhn.on.ca [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, ON (Canada); Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Weinberg, Vivian [University of California San Francisco Helen Diller Family Comprehensive Cancer Center Biostatistics Core, San Francisco, California (United States); Ma, Lijun [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States); Chang, Eric [Department of Radiation Oncology, University of Southern California and University of Texas MD Anderson Cancer Center, University of Texas, Houston, Texas (United States); Chao, Sam [Department of Radiation Oncology and Neurosurgery, Cleveland Clinic, Cleveland, Ohio (United States); Muacevic, Alexander [European Cyberknife Center Munich in affiliation with University Hospitals of Munich, Munich (Germany); Gorgulho, Alessandra [Department of Neurosurgery, University of California at Los Angeles, Los Angeles, California (United States); Soltys, Scott [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Gerszten, Peter C. [Departments of Neurological Surgery and Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States); Ryu, Sam [Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan (United States); Angelov, Lilyana [Department of Radiation Oncology and Neurosurgery, Cleveland Clinic, Cleveland, Ohio (United States); Gibbs, Iris [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Wong, C. Shun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Larson, David A. [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States)
2013-02-01
Purpose: Dose-volume histogram (DVH) results for 9 cases of post spine stereotactic body radiation therapy (SBRT) radiation myelopathy (RM) are reported and compared with a cohort of 66 spine SBRT patients without RM. Methods and Materials: DVH data were centrally analyzed according to the thecal sac point maximum (Pmax) volume, 0.1- to 1-cc volumes in increments of 0.1 cc, and to the 2 cc volume. 2-Gy biologically equivalent doses (nBED) were calculated using an {alpha}/{beta} = 2 Gy (units = Gy{sub 2/2}). For the 2 cohorts, the nBED means and distributions were compared using the t test and Mann-Whitney test, respectively. Significance (P<.05) was defined as concordance of both tests at each specified volume. A logistic regression model was developed to estimate the probability of RM using the dose distribution for a given volume. Results: Significant differences in both the means and distributions at the Pmax and up to the 0.8-cc volume were observed. Concordant significance was greatest for the Pmax volume. At the Pmax volume the fit of the logistic regression model, summarized by the area under the curve, was 0.87. A risk of RM of 5% or less was observed when limiting the thecal sac Pmax volume doses to 12.4 Gy in a single fraction, 17.0 Gy in 2 fractions, 20.3 Gy in 3 fractions, 23.0 Gy in 4 fractions, and 25.3 Gy in 5 fractions. Conclusion: We report the first logistic regression model yielding estimates for the probability of human RM specific to SBRT.
The Hawking radiation of the charged particle via tunnelling from the axisymmetric Sen black hole
Institute of Scientific and Technical Information of China (English)
Jiang Qing-Quan; Yang Shu-Zheng; Chen De-You
2006-01-01
Extending Parikh's semi-classical quantum tunnelling model, this paper has studied the Hawking radiation of the charged particle via tunnelling from the horizon of the axisymmetric Sen black hole. Different from the uncharged massless particle, the geodesies of the charged massive particle tunnelling from the horizon is not light-like. The derived result supports Parikh's opinion and provides a correct modification to Hawking strictly thermal spectrum developed by the fixed background space-time and not considering the energy conservation and the self-gravitation interaction.
Hawking Radiation of Massive Vector Particles From Warped AdS$_{\\text{3}}$ Black Hole
Gursel, H
2015-01-01
Hawking radiation (HR) of massive vector particles from a rotating Warped Anti-de Sitter black hole in 2+1 dimensions (WAdS$_{\\text{3}}$BH) is studied in detail. The quantum tunneling approach with the Hamilton-Jacobi method (HJM) is applied in the Proca equation (PE), and we show that the radial function yields the tunneling rate of the outgoing particles. Comparing the result obtained with the Boltzmann factor, we satisfactorly reproduce the Hawking temperature (HT) of the WAdS$_{\\text{3}}$BH.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
Pu, Jin; Han, Yan
2016-08-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Hawking Radiation of Scalar and Vector Particles From 5D Myers-Perry Black Holes
Jusufi, Kimet
2016-01-01
In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry (5D-MPBH) black hole with two independent angular momentum componentes. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlev\\'e coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equation by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.
Effect Of Black Carbon Radiative Heating On Cloud Microphysics Over Indo-Gangetic Basin
Ghosh, A.; Tripathi, S. N.
2008-12-01
Airborne black carbon (BC), the most significant particulate absorber of solar radiation in the atmosphere, is an important contributor to both global and regional-scale climate forcing (Tripathi et al., 2005). In context of cloud microphysics, freshly emitted pure BC particles are hydrophobic (i.e., bad cloud condensation nuclei (CCN)). However, exposure in the atmosphere may transform BC to a hydrophilic state if these particles are coated with additional materials, such as sulfate and organic carbon (OC). In a recent study, Conant et al. (2002) has examined the effect of radiative heating of BC on the critical supersaturation spectrum of internally mixed aerosols. Two main uncertainties introduced in this work are due to lack of knowledge of actual state of mixing and realistic distributions of different aerosol species. Indo-Gangetic Basin (IGB) in the northern India is one of the most polluted regions in the world. The cloud microphysical processes in IGB are very complex and it requires an in depth investigation for understanding of the aerosol-cloud interaction in the region (Tripathi, et al., 2007). In the present work, an attempt has been made to study the effect of radiative heating due to BC particles coated with hydrophilic materials on cloud microphysics over IGB. For this purpose, we have used (a) a two-layer radiative parameter model based on Mie theory (Toon and Ackerman, 1981) to calculate the particle (monodisperse) absorption cross section; (b) a three-dimensional (3D) radiative transfer model, the spherical harmonics discrete ordinate method (SHDOM) (Evans,1998), which assumes a tropical continental atmosphere, to simulate the 3D spectral actinic flux over the study region; and (c) Extended Köhler theory (Conant et al., 2002) to simulate the effect the BC radiative heating on cloud droplet activation. The solar wavelength spectrum used ranges from 0.2 to 5 micrometer. Following the in situ measurements and modeling studies on mixing state (Dey
Future directions in therapy of whole body radiation injury
Energy Technology Data Exchange (ETDEWEB)
Cronkite, E.P.
1989-01-01
Clinicians have long known that marked granulocytopenia predisposed patients to bacterial infections either from pathogens or commensal organisms with which an individual usually lives in harmony. Evidence that infection was of major importance derives from several observations: (a) clinical observations of bacterial infection in human beings exposed to atomic bomb radiation in Hiroshima and Nagasaki, in reactor accidents, and in large animals dying from radiation exposure, (b) correlative studies on mortality rate, time of death, and incidence of positive culture in animals, (c) challenge of irradiated animals with normally non-virulent organisms, (d) studies of germ free mice and rats, and (e) studies of the effectiveness of antibiotics in reducing mortality rate. General knowledge and sound experimental data on animals and man clearly demonstrated that the sequelae of pancytopenia (bacterial infection, thrombopenic hemorrhage, and anemia) are the lethal factors. A lot of research was required to demonstrate that there were no mysterious radiations toxins, that hyperheparinemia was not a cause of radiation hemorrhage and that radiation hemorrhage could be prevented by fresh platelet transfusions.
IMPETUS: New Cloudy's radiative tables for accretion onto a galaxy black hole
Ramirez-Velasquez, Jose M; Gabbasov, Ruslan; Cruz, Fidel; Sigalotti, Leonardo Di G
2016-01-01
We present digital tables for the radiative terms that appear in the energy and momentum equations used to simulate the accretion onto supermassive black holes (SMBHs) in the center of galaxies. Cooling and heating rates and radiative accelerations are calculated with two different Spectral Energy Distributions (SEDs). One SED is composed of an accretion disk + [X-ray]-powerlaw, while the other is made of an accretion disk + [Corona]-bremsstrahlung with T_X=1.16 x 10^8 K, where precomputed conditions of adiabatic expansion are included. Quantification of different physical mechanisms at operation are presented, showing discrepancies and similarities between both SEDs in different ranges of fundamental physical parameters (i.e., ionization parameter, density, and temperature). With the recent discovery of outflows originating at sub-parsec scales, these tables may provide a useful tool to model gas accretion processes onto a SMBH.
Mandal, S; Mandal, Samir; Chakrabarti, Sandip K.
2005-01-01
Centrifugal barrier supported boundary layer (CENBOL) of a black hole affects the spectrum exactly in the same way the boundary layer of a neutron star does. The CENBOL is produced due to standing or oscillating shock waves and these shocks accelerate electrons very efficiently and produce a power-law distribution. The accelerated particles in turn emit synchrotron radiation in presence of the magnetic field. We study the spectral properties of an accretion disk as a function of the shock strength, compression ratio, flow accretion rate and flow geometry. In the absence of a satisfactory description of magnetic fields inside the advective disk, we consider the presence of only stochastic fields and use the ratio of the field energy density to the gravitational energy density to be a parameter. Not surprisingly, stronger fields produce stronger humps due to synchrotron radiation. We not only include `conventional' synchrotron emission and Comptonization due to Maxwell-Bolzmann electrons in the gas, we also com...
Radiation flaw detector for testing non-uniform surface bodies of revolution
International Nuclear Information System (INIS)
Radiation flaw detector for testing bodies of revolution with non-uniform surface, welded joints, etc., based on spatial filtration and differentiation of ionizing radiation flux has been described. The calculation of the most important unit of flaw detector - integrators - is made. Experimental studies of the sensitivity have shown, that the radiation flaw detector can be used for rapid testing of products with the sensitivity comparable with the sensitivity of radiographic testing of steel
Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau
Kopacz, M.; Mauzerall, D. L.; Wang, J.; Leibensperger, E. M.; Henze, D. K.; Singh, K.
2011-03-01
The remote and high elevation regions of central Asia are influenced by black carbon (BC) emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5-15 W m-2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.
Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau
Directory of Open Access Journals (Sweden)
M. Kopacz
2011-03-01
Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5–15 W m^{−2} within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.
Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau
Directory of Open Access Journals (Sweden)
M. Kopacz
2010-09-01
Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and estimate the forcing due to the BC induced snow-albedo effect at about 5–15 W m^{−2} within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo accelerates glacier melting. Our analysis can help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.
Effects of Spin on High-Energy Radiation from Accreting Black Holes
Riordan, Michael O'; McKinney, Jonathan C
2016-01-01
Observations of jets in X-ray binaries show a correlation between radio power and black hole spin. This correlation, if confirmed, points towards the idea that relativistic jets may be powered by the rotational energy of black holes. In order to examine this further, we perform general-relativistic radiative transport calculations on magnetically arrested accretion flows, which are known to produce powerful jets via the Blandford-Znajek (BZ) mechanism. We find that the X-ray and gamma-ray emission strongly depend on spin and inclination angle. Surprisingly, the high-energy power does not show the same dependence on spin as the BZ jet power, but instead can be understood as a redshift effect. In particular, photons observed perpendicular to the spin axis suffer little net redshift until originating from close to the horizon. Such observers see deeper into the hot, dense, highly-magnetized inner disk region. This effect is largest for rapidly rotating black holes due to a combination of frame dragging and decre...
Energy Technology Data Exchange (ETDEWEB)
Kojima, Yasufumi; Nakamura, Takashi (Kyoto Univ. (Japan). Dept. of Physics)
1984-01-01
Using the Sasaki-Nakamura equation, we have computed the energy, linear and angular momentum of the gravitational radiation induced by a particle of mass ..mu.. and angular momentum ..mu..Lsub(z) plunging in an equatorial plane into a Kerr black hole of mass M(>>..mu..) and angular momentum Ma. It is found that the total energy ..delta..E approximately equal (..mu../M)..mu..c/sup 2/ is emitted by the particle with sufficient large orbital angular momentum. For the same value of /sup +/Lsub(z)/sup +/, a corotating particle emits more energy than a counter-rotating one. We have also calculated the energy from a rotating ring plunging into a Kerr black hole. In this case, we have found that a corotating ring emits less gravitational energy than a counter-rotating one for the same /sup +/Lsub(z)/sup +/. The maximum of the linear momentum is 6 x 10/sup -2/ (..mu../M)..mu..c, which suggests the recoil velocity of the coalesced black hole is 160 km/s for ..mu.. = 0.1 M.
Hawking Radiation of Warped Anti de Sitter and Rotating Hairy Black Holes with Scalar Hair
Gursel, H
2015-01-01
This thesis mainly focuses on the Hawking radiation (HR) evacuating from the surface of the objects that have earned a reputation as the most extraordinary objects existing so far; the black holes (BHs). Throughout this study, quantum tunneling (QT) process serves as the model for the HR of scalar, vector and Dirac particles. The scalar and Dirac particles are anticipated to be tunneling through the horizon of rotating scalar hairy black holes (RHSBHs); whilst the vector particles are associated with a rotating warped anti de-Sitter black hole (WAdS3BH) embedded in a (2+1) dimensional fabric. It is no coincidence that for all three cases; the standard HT expression is derived. Additionally, the engagement of conformal field theory (CFT) with anti de-Sitter (AdS) space presents itself to the reader and the methodologies of Klein-Gordon equation (KGE), Dirac equation and Proca equations (PEs) are introduced. For all three cases, Hamilton-Jacobi (HJ) approach is used, together with Wentzel-Kramers-Brillouin (WKB...
Gitau, Tabither M; Micklesfield, Lisa K; Pettifor, John M; Norris, Shane A
2014-01-01
This cross-sectional study of urban high schools in Johannesburg, South Africa, sought to examine eating attitudes, body image and self-esteem among male adolescents (n = 391). Anthropometric measurements, Eating Attitudes Test-26 (EAT-26), Rosenberg self-esteem, body image satisfaction and perception of females were collected at age 13, 15 and 17 years. Descriptive analysis was done to describe the sample, and non-parametric Wilcoxon Mann-Whitney test was used to test for significant differences between data that were not normally distributed (EAT-26). Spearman's rank correlation coefficient analyses were conducted to test for associations between self-esteem scores and eating attitudes, body mass indices and body image satisfaction scores. To assess the differences between groups that were normally distributed chi-square tests were carried out. Ethnic differences significantly affected adolescent boys' body mass index (BMI), eating attitudes and self-esteem; White boys had higher self-esteem, BMI and normal eating attitudes than the Black boys did. BMI was positively associated with self-esteem (p = 0.01, r = 0.134) and negatively with dieting behaviour in White boys (p = 0.004, r = -0.257), and with lower EAT-26 bulimic and oral control scores in Black boys. In conclusion, the findings highlight ethnic differences and a need to better understand cultural differences that influence adolescent attitudes and behaviour.
Anesthesia and monitoring during whole body radiation in children
DEFF Research Database (Denmark)
Henneberg, S; Nilsson, A; Hök, B;
1990-01-01
) anesthetic technique using midazolam, pancuronium, and fentanyl. With midazolam as the only hypnotic agent, the problem with scavenging is solved, and a computer simulation of the plasma concentration of midazolam is presented. A modified stethoscope for monitoring during radiation also has been developed...
Shankar, Francesco; Weinberg, David H.; Miralda-Escude, Jordi
2007-01-01
We construct evolutionary models of the populations of AGN and supermassive black holes, in which the black hole mass function grows at the rate implied by the observed luminosity function, given assumptions about the radiative efficiency and the Eddington ratio. We draw on a variety of recent X-ray and optical measurements to estimate the bolometric AGN luminosity function and compare to X-ray background data and the independent estimate of Hopkins et al. (2007) to assess remaining systemati...
Quantum Radiation of a Non-stationary Kerr-Newman Black Hole in de Sitter Space-Time
Institute of Scientific and Technical Information of China (English)
JIANG Qing-Quan; YANG Shu-Zheng
2006-01-01
Hawking radiation of Klein-Gordon and Dirac particles in a non-stationary Kerr-Newman-de-Sitter black hole is studied by introducing a new tortoise coordinate transformation. The result shows that the Fermi-Dirac radiant spectrum displays a new term that represents the interaction between the spin of spinor particles and the rotation of black holes, which is absent in the Bose-Einstein distribution of Klein-Gordon particles.
Institute of Scientific and Technical Information of China (English)
ZHAO Wei-Qin; LEI Jie-Hong; LIU Zhi-Xiang; YANG Shu-Zheng
2008-01-01
Extending the Parikh's quantum tunneling method of an uncharged particle, we investigate the quantum radiation characteristics of a particle with electric and magnetic charge via tunneling from the event horizon of theKerr-Newman-Kasuya black hole. The derived result supports the Parikh's opinion and the correction to the thermal spectrum is of precisely the form that satisfies the underlying unitary quantum theory, and finally provides a might explanation to the black hole information puzzle.
DEFF Research Database (Denmark)
Jeppesen, Stefan Starup; Schytte, Tine; Jensen, Henrik R;
2013-01-01
Abstract Introduction. Stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) is now an accepted and patient friendly treatment, but still controversy exists about its comparability to conventional radiation therapy (RT). The purpose of this single...... and SBRT predicted improved prognosis. However, staging procedure, confirmation procedure of recurrence and technical improvements of radiation treatment is likely to influence outcomes. However, SBRT seems to be as efficient as conventional RT and is a more convenient treatment for the patients....
Babak, Stanislav; Buonanno, Alessandra
2016-01-01
In Ref. [1], the properties of the first gravitational wave detected by LIGO, GW150914, were measured by employing an effective-one-body (EOB) model of precessing binary black holes whose underlying dynamics and waveforms were calibrated to numerical-relativity (NR) simulations. Here, we perform the first extensive comparison of such EOBNR model to 70 precessing NR waveforms that span mass ratios from 1 to 5, dimensionless spin magnitudes up to 0.5, generic spin orientations, and length of about 20 orbits. We work in the observer's inertial frame and include all $\\ell=2$ modes in the gravitational-wave polarizations. We introduce new prescriptions for the EOB ringdown signal concerning its spectrum and time of onset. For total masses between 10Msun and 200Msun, we find that precessing EOBNR waveforms have unfaithfulness within about 3% to NR waveforms when considering the Advanced-LIGO design noise curve. This result is obtained without recalibration of the inspiral-plunge of the underlying nonprecessing EOBN...
Improved approximate inspirals of test-bodies into Kerr black holes
Gair, J R; Gair, Jonathan R; Glampedakis, Kostas
2006-01-01
We present an improved version of the approximate scheme for generating inspirals of test-bodies into a Kerr black hole recently developed by Glampedakis, Hughes and Kennefick. Their original "hybrid" scheme was based on combining exact relativistic expressions for the evolution of the orbital elements (the semi-latus rectum p and eccentricity e) with approximate, weak-field, formula for the energy and angular momentum fluxes, amended by the assumption of constant inclination angle, iota, during the inspiral. Despite the fact that the resulting inspirals were overall well-behaved, certain pathologies remained for orbits in the strong field regime and for orbits which are nearly circular and/or nearly polar. In this paper we eliminate these problems by incorporating an array of improvements in the approximate fluxes. Firstly, we add certain corrections which ensure the correct behaviour of the fluxes in the limit of vanishing eccentricity and/or 90 degrees inclination. Secondly, we use higher order post-Newton...
Radiative processes of two entangled atoms outside a Schwarzschild black hole
Menezes, G
2015-01-01
We consider radiative processes of a quantum system composed by two identical two-level atoms in a black-hole background. We assume that these identical two-level atoms are placed at fixed radial distances outside a Schwarzschild black hole and interacting with quantum electromagnetic fluctuations in the Boulware, Unruh and Hartle-Hawking vacuum states. We study the structure of the rate of variation of the atomic energy. The intention is to identify in a quantitative way the contributions of vacuum fluctuations and radiation reaction to the entanglement generation between the atoms as well as the degradation of entangled states in the presence of an event horizon. We find that for a finite observation time the atoms can become entangled for the case of the field in the Boulware vacuum state, even if they are initially prepared in a separable state. In addition, the rate of variation of atomic energy is not well behaved at the event horizon due to the behavior of the proper accelerations of the atoms. We show...
Barausse, Enrico; Chamberlain, Katherine
2016-01-01
The aLIGO detection of the black-hole binary GW150914 opened a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by five orders of magnitude relative to current constraints, probing extreme gravity with unprecedented accuracy.
Computation of radiation from wire antennas on conducting bodies
DEFF Research Database (Denmark)
Albertsen, N. Christian; Hansen, Jesper; Jensen, Niels E.
1974-01-01
A theoretical formulation, in terms of combined magnetic and electric field integral equations, is presented for the class of electromagnetic problems in which one or more wire antennas are connected to a conducting body of arbitrary shape. The formulation is suitable for numerical computation...
Location of alien bodies in a media according to the data of scattering gamma radiation
International Nuclear Information System (INIS)
Locations of alien bodies in a medium are studied by the method of model experiment using scattering γ-radiation. 60Co and 137Cs were used as radiation sources. The scattering bodies were made in the form of aluminium, iron and lead cylinders of different diameters inserted inside hollow cylindrical water, aluminium and iron media. The cases are reviewed when the alien bodies are in the center of cylindrical media. The obtained data are presented in the graphical form and in the form of tables. 4 refs., 4 figs. 1 tab
International Nuclear Information System (INIS)
Purpose: To identify dose–volume factors associated with radiation pneumonitis (RP) after stereotactic body radiation therapy (SBRT) for lung cancer. Methods and Materials: This study analyzed 74 patients who underwent SBRT for primary lung cancer. The prescribed dose for SBRT was uniformly 48 Gy in four fractions at the isocenter. RP was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) v.3. Symptomatic RP was defined as grade 2 or worse. Optimal cut-offs dividing the patient population into two subgroups based on the incidence of symptomatic RP were sought using the following dose–volume metrics: PTV volume (ml), mean lung dose (Gy), and V5, V10, V15, V20, V25, V30, V35, and V40 (%) of both lungs excluding the PTV. Results: With a median follow-up duration of 31.4 months, symptomatic RP was observed in 15 patients (20.3%), including 1 patient with grade 3. Optimal cut-offs for pulmonary dose–volume metrics were V25 and V20. These two factors were highly correlated with each other, and V25 was more significant. Symptomatic RP was observed in 14.8% of the patients with V25 <4.2%, and the rate was 46.2% in the remainder (p = 0.019). PTV volume was another significant factor. The symptomatic RP rate was significantly lower in the group with PTV <37.7 ml compared with the larger PTV group (11.1% vs. 34.5%, p = 0.020). The patients were divided into three subgroups (patients with PTV <37.7 ml; patients with, PTV ≥37.7 ml and V25 <4.2%; and patients with PTV ≥37.7 ml and V25 ≥4.2%); the incidence of RP grade 2 or worse was 11.1%, 23.5%, and 50.0%, respectively (p = 0.013). Conclusions: Lung V25 and PTV volume were significant factors associated with RP after SBRT.
Development of Functional Foods for Body Protection Using Radiation
International Nuclear Information System (INIS)
We have previously developed two herbal compositions(HemoHIM, HemoTonic) that protects immune/hematopoietic system and self-renewal tissues against radiation and enhances immune/hematopoietic functions. In this study, we tried to expand its usability by verifying its protective activity against various harmful stimuli as well as radiation. HemoHIM was shown to be highly effective in reducing immune/hematopoietic damage, particularly, normalizing the Th1/Th2 imbalance, which seemed to be a result of increased production of IL-12p70 by APC and enhanced NK cell activity. Also HemoHIM was shown to have protective activities against UV-induced skin damage, immune system damage by an anticancer drug (CP), immune depression by old age and stress, and inflammation. Finally it was confirmed in a human study that HemoHIM improves the immune cell functions and cytokine production. Based on these results, HemoHIM has been approved as a health functional food for immunomodulation by Korea FDA and succeeded in its industrialization. Meanwhile, to develop functional foods for the reduction of chronic radiation damage (carcinogenesis), we have screened natural products for inhibitory activities against carcinogenesis-related factors, and developed two anti-carcinogenic compositions. Also 6 single compounds were isolated and identified from radioprotective natural products and elucidated some synergistic protection by several single compounds and established a basis for the development of advanced technology for radioprotection. Also, to obtain the applicability of radiation technology for the safe sanitatation and distribution of functional food materials, we verified the toxicological safety, stability of activity and active components of irradiated medicinal herbs
Development of Functional Foods for Body Protection Using Radiation
Energy Technology Data Exchange (ETDEWEB)
Jo, S. K.; Jung, U. H.; Park, H. R.
2007-07-15
We have previously developed two herbal compositions(HemoHIM, HemoTonic) that protects immune/hematopoietic system and self-renewal tissues against radiation and enhances immune/hematopoietic functions. In this study, we tried to expand its usability by verifying its protective activity against various harmful stimuli as well as radiation. HemoHIM was shown to be highly effective in reducing immune/hematopoietic damage, particularly, normalizing the Th1/Th2 imbalance, which seemed to be a result of increased production of IL-12p70 by APC and enhanced NK cell activity. Also HemoHIM was shown to have protective activities against UV-induced skin damage, immune system damage by an anticancer drug (CP), immune depression by old age and stress, and inflammation. Finally it was confirmed in a human study that HemoHIM improves the immune cell functions and cytokine production. Based on these results, HemoHIM has been approved as a health functional food for immunomodulation by Korea FDA and succeeded in its industrialization. Meanwhile, to develop functional foods for the reduction of chronic radiation damage (carcinogenesis), we have screened natural products for inhibitory activities against carcinogenesis-related factors, and developed two anti-carcinogenic compositions. Also 6 single compounds were isolated and identified from radioprotective natural products and elucidated some synergistic protection by several single compounds and established a basis for the development of advanced technology for radioprotection. Also, to obtain the applicability of radiation technology for the safe sanitatation and distribution of functional food materials, we verified the toxicological safety, stability of activity and active components of irradiated medicinal herbs
Directory of Open Access Journals (Sweden)
Sarah K Meadows
Full Text Available In the event of a terrorist-mediated attack in the United States using radiological or improvised nuclear weapons, it is expected that hundreds of thousands of people could be exposed to life-threatening levels of ionizing radiation. We have recently shown that genome-wide expression analysis of the peripheral blood (PB can generate gene expression profiles that can predict radiation exposure and distinguish the dose level of exposure following total body irradiation (TBI. However, in the event a radiation-mass casualty scenario, many victims will have heterogeneous exposure due to partial shielding and it is unknown whether PB gene expression profiles would be useful in predicting the status of partially irradiated individuals. Here, we identified gene expression profiles in the PB that were characteristic of anterior hemibody-, posterior hemibody- and single limb-irradiation at 0.5 Gy, 2 Gy and 10 Gy in C57Bl6 mice. These PB signatures predicted the radiation status of partially irradiated mice with a high level of accuracy (range 79-100% compared to non-irradiated mice. Interestingly, PB signatures of partial body irradiation were poorly predictive of radiation status by site of injury (range 16-43%, suggesting that the PB molecular response to partial body irradiation was anatomic site specific. Importantly, PB gene signatures generated from TBI-treated mice failed completely to predict the radiation status of partially irradiated animals or non-irradiated controls. These data demonstrate that partial body irradiation, even to a single limb, generates a characteristic PB signature of radiation injury and thus may necessitate the use of multiple signatures, both partial body and total body, to accurately assess the status of an individual exposed to radiation.
Institute of Scientific and Technical Information of China (English)
ZHANG Hong-Bao; CAO Zhou-Jian; GAO Chong-Shou
2004-01-01
Si-Jie Gao has recently investigated Hawking radiation from spherically symmetrical gravitational collapse to an extremal R-N black hole for a real scalar field. Especially he estimated the upper bound for the expected number of particles in any wave packet belonging to Hout spontaneously produced from the state |0＞in, which confirms the traditional belief that extremal black holes do not radiate particles. Making some modifications, we demonstrate that the analysis can go through for a charged scalar field.
Institute of Scientific and Technical Information of China (English)
2007-01-01
At the event horizon and the cosmological horizon of the stationary axisymmetric Kerr-Newman black hole in the de Sitter space-time background, the tunneling rate of the charged particles is relevant with Bekenstein-Hawking entropy and the real radiation spectrum is not strictly pure thermal, but consistent with the underlying unitary theory in quantum mechanics. This is a feasible interpretation for the paradox of the black hole information loss. Taking the self-gravitation action, energy conservation, angular momentum conservation and charge conservation into account, the derived radiation spectrum is a correct amendment to the Hawking pure thermal spectrum.
Capodilupo, Christina M
2015-04-01
Very few empirical studies have investigated the effect that culturally relevant beauty ideals (such as long, straight hair and lighter skin tones) have on Black women's feelings about their physical appearance. The current investigation examined the direct effect of internalizing idealized media images on Black women's body esteem and appearance satisfaction. The indirect effects of: (a) the presumed influence of the media images on African American men, and (b) feelings of invisibility were also tested. Using an online survey, the sample included 230 women who identified as African American and/or Black American. Through structural equation modeling (SEM), findings reveal that participants' body esteem was directly negatively impacted by higher levels of internalization of idealized media images. Further, the findings support the idea that higher levels of internalization of media lead to a greater presumed influence of media on men, which leads to higher feelings of invisibility, ultimately leading to lower body esteem. Finally, there was evidence to suggest that appearance satisfaction was not directly negatively affected by internalization of media images but was negatively impacted when the images are presumed to have a higher influence on African American men. PMID:25150817
Black Holes and Gravitational Properties of Antimatter
Hajdukovic, D
2006-01-01
We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.
Mustillo, Sarah A; Hendrix, Kimber L; Schafer, Markus H
2012-03-01
As a stigmatizing condition, obesity may lead to the internalization of devalued labels and threats to self-concept. Modified labeling theory suggests that the effects of stigma may outlive direct manifestations of the discredited characteristic itself. This article considers whether obesity's effects on self-concept linger when obese youth enter the normal body mass range. Using longitudinal data from the National Growth and Health Study on 2,206 black and white girls, we estimated a parallel-process growth mixture model of body mass linked to growth models of body image discrepancy and self-esteem. We found that discrepancy was higher and self-esteem lower in formerly obese girls compared to girls always in the normal range and comparable to chronically obese girls. Neither body image discrepancy nor self-esteem rebounded in white girls despite reduction in body mass, suggesting that the effects of stigma linger. Self-esteem, but not discrepancy, did rebound in black girls. PMID:22382717
Das, Upasana
2013-01-01
We study the effects of optically thin radiative cooling on the structure of radiatively inefficient accretion flows (RIAFs). The flow structure is geometrically thick, and independent of the gas density and cooling, if the cooling time is longer than the viscous timescale (i.e., $t_{\\rm cool} \\gtrsim t_{\\rm visc}$). For higher densities, the gas can cool before it can accrete and forms the standard geometrically thin, optically thick Shakura-Sunyaev disk. For usual cooling processes (such as bremsstrahlung), we expect an inner hot flow and an outer thin disk. For a short cooling time the accretion flow separates into two phases: a radiatively inefficient hot coronal phase and a cold thin disk. We argue that there is an upper limit on the density of the hot corona corresponding to a critical value of $t_{\\rm cool}/t_{\\rm ff} (\\sim 10-100)$, the ratio of the cooling time and the free-fall time. Based on our simulations, we have developed a model for observed transients in black hole X-ray binaries (XRBs). An X...
Consequences of Radiative and Mechanical Feedback from Black Holes in Galaxy Mergers
Choi, Ena; Ostriker, Jeremiah P; Johansson, Peter H; Moster, Benjamin P
2013-01-01
We employ hydrodynamical simulations to study the effect of AGN mechanical and radiation feedback on the formation of bulge dominated galaxies via mergers of disk galaxies. The merging galaxies have mass-ratios of 1:1 to 6:1 and include pre-existing hot gaseous halos to properly account for the global impact of AGN feedback. We compare three models: (1) no black hole and no AGN feedback; (2) thermal AGN feedback; and (3) mechanical and radiative AGN feedback. The last model is motivated by observations of broad absorption line quasars which show winds with initial velocities of v_w ~ 10,000 km/s and also heating associated with the central AGN X-ray radiation. The primary changes in gas properties due to mechanical AGN feedback are lower thermal X-ray luminosity from the final galaxy - in better agreement with observations - and galactic outflows with higher velocity ~ 1000 km/s similar to recent direct observations of nearby merger remnants. The kinetic energy of the outflowing gas is a factor of ~ 20 higher...
Stereotactic Body Radiation Therapy (SBRT) for Unresectable Pancreatic Carcinoma
International Nuclear Information System (INIS)
Survival in patients with unresectable pancreatic carcinoma is poor. Studies by Mayo Clinic and the Gastrointestinal Tumor Study Group (GITSG) have established combined modality treatment with chemotherapy and radiation as the standard of care. Use of gemcitabine-based chemotherapy alone has also been shown to provide a benefit, but 5‑year overall survival still remains less than 5%. Conventional radiotherapy is traditionally delivered over a six week period and high toxicity is seen with the concomitant use of chemotherapy. In contrast, SBRT can be delivered in 3–5 days and, when used as a component of combined modality therapy with gemcitabine, disruption to the timely delivery of chemotherapy is minimal. Early single-institution reports of SBRT for unresectable pancreatic carcinoma demonstrate excellent local control with acceptable toxicity. Use of SBRT in unresectable pancreatic carcinoma warrants further investigation in order to improve the survival of patients with historically poor outcomes
Umemura, Masayuki
2001-01-01
As a potential mechanism to build up supermassive black holes (BHs) in a spheroidal system, we consider the radiation drag effect by bulge stars, which extracts angular momentum from interstellar gas and thus allows the gas to accrete onto the galactic center. With incorporating radiation hydrodynamical equation with simple stellar evolution, it is shown that the BH-to-bulge mass ratio, $f_{BH}$, is basically determined by a fundamental constant, that is, the energy conversion efficiency for ...
Chromosomal Translocations in Black Flies (Diptera: Simuliidae)—Facilitators of Adaptive Radiation?
Adler, Peter H.; Yadamsuren, Oyunchuluun; Procunier, William S.
2016-01-01
A macrogenomic investigation of a Holarctic clade of black flies—the Simulium cholodkovskii lineage—provided a platform to explore the implications of a unique, synapomorphic whole-arm interchange in the evolution of black flies. Nearly 60 structural rearrangements were discovered in the polytene complement of the lineage, including 15 common to all 138 analyzed individuals, relative to the central sequence for the entire subgenus Simulium. Three species were represented, of which two Palearctic entities (Simulium cholodkovskii and S. decimatum) were sympatric; an absence of hybrids confirmed their reproductive isolation. A third (Nearctic) entity had nonhomologous sex chromosomes, relative to the other species, and is considered a separate species, for which the name Simulium nigricoxum is revalidated. A cytophylogeny is inferred and indicates that the two Palearctic taxa are sister species and these, in turn, are the sister group of the Nearctic species. The rise of the S. cholodkovskii lineage encompassed complex chromosomal and genomic restructuring phenomena associated with speciation in black flies, viz. expression of one and the same rearrangement as polymorphic, fixed, or sex linked in different species; taxon-specific differentiation of sex chromosomes; and reciprocal translocation of chromosome arms. The translocation is hypothesized to have occurred early in male spermatogonia, with the translocated chromosomal complement being transmitted to the X- and Y-bearing sperm during spermatogenesis, resulting in alternate disjunction of viable F1 translocation heterozygotes and the eventual formation of more viable and selectable F2 translocation homozygous progeny. Of 11 or 12 independently derived whole-arm interchanges known in the family Simuliidae, at least six are associated with subsequent speciation events, suggesting a facilitating role of translocations in adaptive radiations. The findings are discussed in the context of potential structural and
Chromosomal Translocations in Black Flies (Diptera: Simuliidae-Facilitators of Adaptive Radiation?
Directory of Open Access Journals (Sweden)
Peter H Adler
Full Text Available A macrogenomic investigation of a Holarctic clade of black flies-the Simulium cholodkovskii lineage-provided a platform to explore the implications of a unique, synapomorphic whole-arm interchange in the evolution of black flies. Nearly 60 structural rearrangements were discovered in the polytene complement of the lineage, including 15 common to all 138 analyzed individuals, relative to the central sequence for the entire subgenus Simulium. Three species were represented, of which two Palearctic entities (Simulium cholodkovskii and S. decimatum were sympatric; an absence of hybrids confirmed their reproductive isolation. A third (Nearctic entity had nonhomologous sex chromosomes, relative to the other species, and is considered a separate species, for which the name Simulium nigricoxum is revalidated. A cytophylogeny is inferred and indicates that the two Palearctic taxa are sister species and these, in turn, are the sister group of the Nearctic species. The rise of the S. cholodkovskii lineage encompassed complex chromosomal and genomic restructuring phenomena associated with speciation in black flies, viz. expression of one and the same rearrangement as polymorphic, fixed, or sex linked in different species; taxon-specific differentiation of sex chromosomes; and reciprocal translocation of chromosome arms. The translocation is hypothesized to have occurred early in male spermatogonia, with the translocated chromosomal complement being transmitted to the X- and Y-bearing sperm during spermatogenesis, resulting in alternate disjunction of viable F1 translocation heterozygotes and the eventual formation of more viable and selectable F2 translocation homozygous progeny. Of 11 or 12 independently derived whole-arm interchanges known in the family Simuliidae, at least six are associated with subsequent speciation events, suggesting a facilitating role of translocations in adaptive radiations. The findings are discussed in the context of potential
Woodhead, D S
1986-12-31
A variety of fission-product and transuranic radionuclides originating from the marine discharges from the fuel reprocessing plant at Sellafield, Cumbria are detectable in the bodies of black-headed gulls and their environment in the Ravenglass Estuary approximately 10 km to the south-west of the plant. The maximum concentrations of 95Nb, 137Cs and 239/240Pu detected in body tissues lie in the range 2 X 10(-3) to 1.5 X 10(-2) Bqg-1 wet weight. Many more radionuclides are detected in the regurgitated pellets and faeces produced by the gulls and have higher concentrations in the range 7 X 10(-3) to 1.7 Bqg-1 wet weight. The radionuclide contamination of the sediment produces a source of enhanced external gamma-ray exposure which can be measured directly. The available data on distributions and concentrations of radionuclides have been combined with simple dosimetry models to provide estimates of the radiation exposure of the birds. The total whole body dose rate to the adult birds from the contaminant radionuclides is approximately ten times that from the natural radiation background, while that to the developing eggs is approximately four times the natural background. The potential radiation exposure of the cells lining the alimentary tract could be much higher when contaminated food is in transit, but the long-term average exposure in this case is subject to uncertainty. The limited data on the effects of radiation exposure on birds do not indicate any response at dose rates below one hundred times that from the natural radiation background.(ABSTRACT TRUNCATED AT 250 WORDS)
Li, Jin; Yang, Nan
2014-01-01
Based on a regular exact black hole (BH) from nonlinear electrodynamics (NED) coupled to General Relativity, we investigate its stability of such BH though the Quasinormal Modes (QNMs) of electromagnetic (EM) field perturbation and its thermodynamics through Hawking radiation. In perturbation theory, we can deduce the effective potential from nonlinear EM field. The comparison of potential function between regular and RN BHs could predict their similar QNMs. The QNMs frequency tell us the effect of magnetic charge $q$, overtone $n$, angular momentum number $l$ on the dynamic evolution of NED EM field. Furthermore we also discuss the cases near extreme condition (called as strong charged cases) of such magnetically charged regular BH, the corresponding QNMs spectrum illuminates some special properties in the strong charged cases. For the thermodynamics, we employ Hamilton-Jacobi method to calculate the near-horizon Hawking temperature of the regular BH and reveal the relationship between classical parameters o...
Emergent horizon, Hawking radiation and chaos in the collapsed polymer model of a black hole
Brustein, Ram
2016-01-01
We have proposed that the interior of a macroscopic Schwarzschild black hole (BH) consists of highly excited, long, closed, interacting strings and, as such, can be modeled as a collapsed polymer. It was previously shown that the scaling relations of the collapsed-polymer model agree with those of the BH. The current paper further substantiates this proposal with an investigation into some of its dynamical consequences. In particular, we show that the model predicts, without relying on gravitational effects, an emergent horizon. We further show that the horizon fluctuates quantum mechanically as it should and that the strength of the fluctuations is inversely proportional to the BH entropy. It is then demonstrated that the emission of Hawking radiation is realized microscopically by the quantum-induced escape of small pieces of string, with the rate of escape and the energy per emitted piece both parametrically matching the Hawking temperature. We also show, using standard methods from statistical mechanics a...
Energy Technology Data Exchange (ETDEWEB)
Li, Jin [Chongqing University, Department of Physics, Chongqing (China); Lin, Kai [Universidade de Sao Paulo, Instituto de Fisica, CP 66318, Sao Paulo (Brazil); Yang, Nan [Huazhong University of Science and Technology, Department of Physics, Wuhan (China)
2015-03-01
Based on a regular exact black hole (BH) from nonlinear electrodynamics (NLED) coupled to general relativity, we investigate the stability of such BH through the Quasinormal Modes (QNMs) of electromagnetic (EM) field perturbations and its thermodynamics through Hawking radiation. In perturbation theory, we can deduce the effective potential from a nonlinear EM field. The comparison of the potential function between regular and RN BHs could predict similar QNMs. The QNM frequencies tell us the effect of the magnetic charge q, the overtone n, and the angular momentum number l on the dynamic evolution of NLED EM field. Furthermore we also discuss the cases of near-extreme conditions of such a magnetically charged regular BH. The corresponding QNM spectrum illuminates some special properties in the near-extreme cases. For the thermodynamics, we employ the Hamilton-Jacobi method to calculate the near-horizon Hawking temperature of the regular BH and reveal the relationship between the classical parameters of the black hole and its quantum effects. (orig.)
Hot accretion flow with radiative cooling: state transitions in black hole X-ray binaries
Wu, Mao-Chun; Yuan, Ye-Fei; Gan, Zhao-Ming
2016-01-01
We investigate state transitions in black hole X-ray binaries through different parameters by using two-dimensional axisymmetric hydrodynamical simulation method. For radiative cooling in hot accretion flow, we take into account the bremsstrahlung, synchrotron and synchrotron-self Comptonization self-consistently in the dynamics. Our main result is that the state transitions occur when the accretion rate reaches a critical value $\\dot M \\sim 3\\alpha\\ \\dot M_{\\rm Edd}$, above which cold and dense clumpy/filamentary structures are formed, embedded within the hot gas. We argued this mode likely corresponds to the proposed two-phase accretion model, which may be responsible for the intermediate state of black hole X-ray binaries. When the accretion rate becomes sufficiently high, the clumpy/filamentary structures gradually merge and settle down onto the mid-plane. Eventually the accretion geometry transforms to a disc-corona configuration. In summary our results are consistent with the truncated accretion scenari...
Hot accretion flow with radiative cooling: state transitions in black hole X-ray binaries
Wu, Mao-Chun; Xie, Fu-Guo; Yuan, Ye-Fei; Gan, Zhaoming
2016-06-01
We investigate state transitions in black hole X-ray binaries through different parameters by using two-dimensional axisymmetric hydrodynamical simulation method. For radiative cooling in hot accretion flow, we take into account the bremsstrahlung, synchrotron and synchrotron self-Comptonization self-consistently in the dynamics. Our main result is that the state transitions occur when the accretion rate reaches a critical value dot{M} ˜ 3α dot{M}_Edd, above which cold and dense clumpy/filamentary structures are formed, embedded within the hot gas. We argued this mode likely corresponds to the proposed two-phase accretion model, which may be responsible for the intermediate state of black hole X-ray binaries. When the accretion rate becomes sufficiently high, the clumpy/filamentary structures gradually merge and settle down on to the mid-plane. Eventually the accretion geometry transforms to a disc-corona configuration. In summary, our results are consistent with the truncated accretion scenario for the state transition.
Radiation from an accelerating neutral body: The case of rotation
Yarman, Tolga; Arik, Metin; Kholmetskii, Alexander L.
2013-11-01
diatomic molecule, for instance). If the object reaches its final state in a given medium, say air, and "friction" is present, such as the case of a dental drill, then energy should keep being supplied to it, to overcome friction, which is present either inside the "inner mechanism of rotation" or in its surroundings. In other words, the object in the latter case, would be constantly subject to a friction force, countering its motion, and tending to make it fall to lower rotational energy states. Any fluctuations in the power supply, on the other hand, will slow down the rotating object, no matter how indiscernibly. The small decrease in the rotational velocity is yet reincreased by restoring the power supply, thus perpetually securing a stationary rotational motion. Thereby, the object in this final state, due to fluctuations in either friction or power supply, or both, shall further be expected to emit a radiation of energy , where is the final angular velocity of the object in rotation. What is more is that our team has very successfully measured what is predicted here, and they will report their experimental results in a subsequent article. The approach presented here seems to shed light on the mysterious sonoluminescence. It also triggers the possibility of sensing earthquakes due to radiation that should be emitted by the faults, on which the seismic stress keeps increasing until the crackdown. By the same token, also two colliding (neutral) objects are expected to emit radiation.
Rahman, M. Atiqur; Hossain, M. Ilias
2013-06-01
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SAdS black hole.
Rahman, M Atiqur
2013-01-01
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and gives a correction to the Hawking radiation of SAdS black hole.
Steinhauer, Jeff
2016-01-01
The observation of quantum Hawking radiation and its entanglement in an analogue black hole was recently reported. A subsequent note (arXiv:1609.03803) criticized the study. We answer all of the comments in the note and show that the criticisms are not valid. We also answer a comment made by the author of the note in a different forum.
DEFF Research Database (Denmark)
Beermann, Jonas; Eriksen, René L.; Stær, Tobias Holmgaard;
2014-01-01
Plasmonic black surfaces formed by two-dimensional arrays of ultra-sharp convex metal grooves, in which the incident radiation is converted into gap surface plasmon polaritons (GSPPs) and subsequently absorbed (via adiabatic nanofocusing), are fabricated and investigated experimentally for gold...
Zaorsky,Nicholas; Avkshtol,Vladimir; Dong, Yanqun; Hayes, Shelly; Hallman,Mark; Price, Robert; Sobczak, Mark; Horwitz, Eric
2016-01-01
Vladimir Avkshtol, Yanqun Dong, Shelly B Hayes, Mark A Hallman, Robert A Price, Mark L Sobczak, Eric M Horwitz,* Nicholas G Zaorsky* Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA *These authors contributed equally to this work Abstract: Prostate cancer is the most prevalent cancer diagnosed in men in the United States besides skin cancer. Stereotactic body radiation therapy (SBRT; 6–15 ...
Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan
2015-08-01
Three different internal mixing methods (Core-Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20-70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20-50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core-Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC-sulfate aerosol is about -3.18 W/m2 for the external method and -6.91 W/m2 for the internal methods at the surface, and -3.03/-1.56/-1.85 W/m2 for the external/Core-Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause.
Induced radiation processes in single-bubble sonoluminescence
Prigara, Fedor V.
2005-01-01
According to the recent revision of the theory of thermal radiation, thermal black-body radiation has an induced origin. We show that in single-bubble sonoluminescence thermal radiation is emitted by a spherical resonator, coincident with the sonoluminescing bubble itself, instead of the ensemble of elementary resonators emitting thermal black-body radiation in the case of open gaseous media. For a given wavelength, the diameter of the resonator is fixed, and this explains the very high const...
Energy Technology Data Exchange (ETDEWEB)
Duran, E.B.; Napenas, D.; San Jose, V.; Juan, N.
The body burden of I-131 was determined among the radiation workers of the Philippine Atomic Energy Commission (PAEC) who are directly involved in I-131 processing and nuclear laboratory technicians of University of Santo Tomas and Veterans Hospital, who handle and dispense I-131 to patients. The routine monitoring was done by urine analysis. The untreated urine samples were counted directly for 4000 seconds using Nal(Tl) scintillation detector coupled to an ND66 microcomputer-based multichannel analyzer. Urine samples of radiation workers of PAEC who are not involved in I-131 processing and non-radiation workers were also assayed for comparison. For radiation workers of PAEC who are directly involved in processing I-131, the estimated body burden of I-131 ranged from <0.055 to 8.53 uCi (282 urine samples). These values were higher than those observed for radiation workers not involved in the handling or processing of I-131 with estimated body burden of I-131 ranging from <0.055 to 0.52 uCi (48 urine samples) or than those observed from non-radiation workers (<0.055 uCi). The maximum permissible burden of I-131 is 0.7 uCi.
Murine partial-body radiation exposure model for biodosimetry studies - Preliminary report
Energy Technology Data Exchange (ETDEWEB)
Blakely, William F., E-mail: blakely@afrri.usuhs.mil [Uniformed Services University, Armed Forces Radiobiology Research Institute, Scientific Research Department, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States); Sandgren, David J., E-mail: Sandgren@afrri.usuhs.mil [Uniformed Services University, Armed Forces Radiobiology Research Institute, Scientific Research Department, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States); Nagy, Vitaly, E-mail: nagy@afrri.usuhs.mil [Uniformed Services University, Armed Forces Radiobiology Research Institute, Scientific Research Department, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States); Kim, Sung-Yop, E-mail: kimy@afrri.usuhs.mil [Uniformed Services University, Armed Forces Radiobiology Research Institute, Scientific Research Department, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States); Ossetrova, Natalia I., E-mail: ossetrova@afrri.usuhs.mil [Uniformed Services University, Armed Forces Radiobiology Research Institute, Scientific Research Department, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603 (United States)
2011-09-15
The objective of the present study was to establish a murine partial-body radiation exposure model for studies supporting the identification and validation of novel biological dosimetry diagnostic assays. A lead shielding - Plexiglas irradiation apparatus with cutouts to permit irradiation of single-mouse-holder constrained CD2F1 male mice to total-body (3/3), mid- and lower-body (2/3), mid-body only (1/3), and 100% lead shielding sham-treated (0 Gy) controls (0/3) with a 250-kVp X-ray source (dose: 6 Gy, dose rate: 0.50 Gy min{sup -1}) was used. Doses and dose uniformity were measured using alanine - electron paramagnetic resonance (EPR) and ionization chambers. Dosimetry mapping results showed {approx}2 and {approx}12% non-uniformity in the radiation fields for the two smaller (1/3, 2/3) and one larger (3/3) fields, respectively. Hematology results showed no marked differences in neutrophil and platelet counts 1 and 2 days (d) after irradiation. The lymphocyte counts, as expected, demonstrate a progressive decline below baseline levels 1 and 2 d after irradiation with increasing fraction of the body exposed, while the neutrophil to lymphocyte ratios show the inverse effect, with a progressive increase with the fraction of body exposed. The bone marrow biomarker, Flt3 ligand, demonstrated a progressive increase in values with increasing fraction of the body exposed; the 2 d response was enhanced compared to 1 d. The radioresponse 1 d after irradiation for the acute phase reactant protein biomarker, serum amyloid A (SAA) that is synthesized by the liver, was significantly influenced depending on whether the mouse head was in the radiation field. Use of multiple biomarkers based on hematology and proteomic targets provide an enhancement in early-phase partial-body radiation exposure assessment.
Ignat Ignatov; Oleg Mosin; Hugo Niggli; Christos Drossinakis; Georg Tyminski
2015-01-01
This paper presents the results of evaluation of possible biophysical methods and approaches for registering of various non-ionizing radiation (NIR) wave types of the human body in the optic and electromagnetic range. Various types of NIR (electromagnetic waves, infrared radiation, thermo radiation, bioluminiscence) emitted from the human body were reviewed. In particular the results on the spontaneous biophoton emission and the delayed luminescence from the human body were submitted along wi...
International Nuclear Information System (INIS)
's research councils have yet to put any real money behind these ideas. Black holes are best described by the general theory of relativity. However, general relativity is a classical theory of gravity, and although its predictions have been verified in many experiments, a quantum theory of gravity remains one of the holy grails of physics. One of the first physicists to make real progress in this quest to reconcile general relativity and quantum mechanics was Stephen Hawking. In 1974 Hawking calculated what would happen if a quantum fluctuation occurred near an event horizon. He concluded that the black hole would radiate, and that the amount of radiation would be inversely proportional to the mass of the black hole. However, black holes tend to be very heavy, so their output of Hawking radiation would be too low to detect experimentally. One intriguing exception could be much smaller primordial black holes created in the big bang: these should radiate observable amounts of gamma rays, but they have not been detected yet. This whole body of work - in which thermodynamic concepts such as temperature and entropy are also associated with the black hole - is Hawking's major achievement in physics. The detection of Hawking radiation is the ultimate goal of experiments on artificial black holes, although a lot of theoretical and experimental work has to be done first. The successful experiment is likely to involve a flowing Bose-Einstein condensate or a medium in which the speed of light can be reduced to zero. After years of groundwork, physicists have recently made rapid progress in both these fields. Meanwhile, the recent observation of neutrons in discrete quantum states in a gravitational potential shows that quantum gravity effects can be seen in the laboratory. All that is needed now is an act of faith. (U.K.)
Huang, Shu-Ming; Chen, Jen-Yin; Chen, Chin-Chu; Su, Chih-Chung; Hu, Miao-Lin
2016-01-01
We investigated the effects of Phellinus linteus extracts (PLEs) against radiation damage in mice. First, BALB/c mice were irradiated once with γ-rays at 4, 5, 6, or 8 Gy and allowed to recover for 20 days. Results reveal that 8-Gy radiation caused death in 100% of mice on day 13, and 6-Gy radiation caused death in 86.7% of mice (13/15) at the end of the experiment, whereas 4- and 5-Gy radiation did not result in any death. We then used 5-Gy γ-ray radiation to examine the protective effects of PLEs. Mice were orally administered a PLE (500, 1000, and 1500 mg/kg) daily for 2 weeks before radiation and for 6 weeks after radiation. γ-Ray radiation significantly decreased body weight starting from week 2 after radiation. Supplementation with a median and high dose of PLE significantly restored body weights starting at weeks 5 and 3, respectively. The radiation-protective agent WR2721 (200 mg/kg intraperitoneally) restored body weights starting at week 4. White blood cells, platelets, red blood cells, and hemoglobin were significantly decreased by radiation, and PLEs (primarily at high doses) and WR2721 significantly prevented hematologic abnormality. These results suggest that PLE has potential as a radioprotective agent. PMID:27649604
Opportunities for Radiosensitization in the Stereotactic Body Radiation Therapy (SBRT) Era.
Moding, Everett J; Mowery, Yvonne M; Kirsch, David G
2016-01-01
Stereotactic body radiation therapy (SBRT) utilizing a small number of high-dose radiation therapy fractions continues to expand in clinical application. Although many approaches have been proposed to radiosensitize tumors with conventional fractionation, how these radiosensitizers will translate to SBRT remains largely unknown. Here, we review our current understanding of how SBRT eradicates tumors, including the potential contributions of endothelial cell death and immune system activation. In addition, we identify several new opportunities for radiosensitization generated by the move toward high dose per fraction radiation therapy. PMID:27441746
Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Levy Zamora, Misti; Zeng, Limin; Shao, Min; Wu, Yu-Sheng; Zheng, Jun; Wang, Yuan; Glen, Crystal R.; Collins, Donald R.; Molina, Mario J.
2016-04-01
Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.
Radiative feedback from quasars and the growth of massive black holes in stellar spheroids
Sazonov, S Y; Ciotti, L; Sunyaev, R A
2004-01-01
We discuss the importance of feedback via photoionization and Compton heating on the co-evolution of massive black holes (MBHs) at the center of spheroidal galaxies and their stellar and gaseous components. We first assess the energetics of the radiative feedback from a typical quasar on the ambient interstellar medium. We then demonstrate that the observed Mbh-sigma relation could be established following the conversion of most of the gas of an elliptical progenitor into stars, specifically when the gas-to-stars mass ratio in the central regions has dropped to a low level ~0.01 or less, so that gas cooling is no longer able to keep up with the radiative heating by the growing central MBH. A considerable amount of the remaining gas will be expelled and both MBH accretion and star formation will proceed at significantly reduced rates thereafter, in agreement with observations of present day ellipticals. We find further support for this scenario by evolving over an equivalent Hubble time a simple, physically ba...
The Nature of Thermal Blackbody Radiation
Prigara, F. V.
2002-01-01
It was shown recently that thermal radio emission has a stimulated character, and it is quite possible that thermal black body radiation in other spectral ranges also has an induced origin. The induced origin of thermal black body emission leads to important astrophysical consequences, such as the existence of laser type sources and thermal harmonics in stellar spectra.
General Tortoise Coordinate Transformation in a Dynamical Kerr-Newman Black Hole
Liu, Xian-Ming; Cheng, Su-Jun; Liu, Wen-Biao
2012-02-01
Under the extended dynamical tortoise coordinate transformation, Damour-Ruffini method has been applied to calculate the charged particles' Hawking radiation from the apparent horizon of a dynamical Kerr-Newman black hole. It is shown that Hawking radiation is still purely thermal black body spectrum. Moreover, the temperature of Hawking radiation is corresponding to the apparent horizon surface gravity and the first law of thermodynamics can also be constructed successfully on the apparent horizon in the dynamical Kerr-Newman black hole.
Ciotti, L
2007-01-01
The importance of the radiative output from massive black holes at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole mass and galaxy optical luminosity. We show how this AGN radiative output affects the hot ISM of an isolated elliptical galaxy with the aid of a high-resolution hydrodynamical code, where the cooling and heating functions include photoionization plus Compton heating. We find that radiative heating is a key factor in the self-regulated coevolution of massive black holes and their host galaxies and that 1) the mass accumulated by the central black hole is limited by feedback to the range observed today, and 2) relaxation instabilities occur so that duty cycles are small enough (~0.03) to account for the very small fraction of massive ellipticals observed to be in the "on" -QSO- phase, when the accretion luminosity approaches the Eddington luminosity. The duty cycle of the hot bubbles inflated at the galaxy center duri...
Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Zheng, Jing; Shang, Dongjie; Zamora, Misti; Zeng, Liming; Shao, Min; Wu, Yusheng; Zheng, Jun; Wang, Yuan; Collins, Don; Zhang, Renyi
2016-04-01
Black carbon (BC) particles, produced from incomplete fossil fuel combustion and biomass burning, are ubiquitous in the atmosphere and have profound impacts on air quality, human health, weather, and climate. For example, in areas identified as aerosol hotspots, which include many urban centers and megacities worldwide, solar heating by BC particles has been shown to be comparable to warming due to the greenhouse gases2. Although BC represents a key short-lived climate forcer, its direct radiative forcing remains highly uncertain. In particular, the available results of absorption enhancement of BC particles during atmospheric aging are conflicting from the previous studies, leading to a large uncertainty in global radiative transfer calculation. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China and Houston, US, using a novel chamber approach. BC aging exhibits two distinct stages - initial transformation from a fractal to spherical morphology with little absorption variation and the subsequent growth of fully compact particles with a maximum absorption enhancement factor of 2.4. The variation in BC direct radiative forcing is highly dependent of the rate and timescale of aging, with an estimated increase of 0.45 (0.21 - 0.80) W m-2 from fresh to fully aged particles. Our results reveal a high climatic impact in polluted environments due to rapid aging and a clear distinction between urban cities in developed and developing countries for BC particles, highlighting a larger than recognized co-benefit in air quality improvement and climate protection by BC mediation.
Radiative Forcing and Climate Response Due to Black Carbon in Snow and Ice
Institute of Scientific and Technical Information of China (English)
WANG Zhili; ZHANG Hua; SHEN Xueshun
2011-01-01
The radiative forcing and climate response due to black carbon (BC) in snow and/or ice were investigated by integrating observed effects of BC on snow/ice albedo into an atmospheric general circulation model (BCC_AGCM2.0.1) developed by the National Climate Center (NCC) of the China Meteorological Administration (CMA).The results show that the global annual mean surface radiative forcing due to BC in snow/ice is +0.042 W m-2,with maximum forcing found over the Tibetan Plateau and regional mean forcing exceeding +2.8 W m-2.The global annual mean surface temperature increased 0.071℃ due to BC in snow/ice.Positive surface radiative forcing was clearly shown in winter and spring and increased the surface temperature of snow/ice in the Northern Hemisphere.The surface temperatures of snow-covered areas of Eurasia and North America in winter (spring) increased by 0.83℃ (0.6℃) and 0.83℃ (0.46℃),respectively.Snowmelt rates also increased greatly,leading to earlier snowmelt and peak runoff times.With the rise of surface temperatures in the Arctic,more water vapor could be released into the atmosphere,allowing easier cloud formation,which could lead to higher thermal emittance in the Arctic. However,the total cloud forcing could decrease due to increasing cloud cover,which will offset some of the positive feedback mechanism of the clouds.
The role of Compton heating in radiation-regulated accretion on to black holes
Park, KwangHo; Ricotti, Massimo; Di Matteo, Tiziana; Reynolds, Christopher S.
2014-12-01
We investigate the role of Compton heating in radiation-regulated accretion on to black holes (BHs) from a neutral dense medium using 1D radiation-hydrodynamic simulations. We focus on the relative effects of Compton-heating and photoheating as a function of the spectral slope α, assuming a power-law spectrum in the energy range of 13.6 eV-100 keV. While Compton heating is dominant only close to the BH, it can reduce the accretion rate to 0.1 (l ∝ dot{m}^2 model)-0.01 per cent (l ∝ dot{m} model) of the Bondi accretion rate when the BH radiation is hard (α ˜ 1), where l and dot{m} are the luminosity and accretion rate normalized by Eddington rates, respectively. The oscillatory behaviour otherwise typically seen in simulations with α > 1, become suppressed when α ˜ 1 only for the l ∝ dot{m} model. The relative importance of the Compton heating over photoheating decreases and the oscillatory behaviour becomes stronger as the spectrum softens. When the spectrum is soft (α > 1.5), photoheating prevails regardless of models making the effect of Compton heating negligible. On the scale of the ionization front, where the gas supply into the Strömgren sphere from large scale is regulated, photoheating dominates. Our simulations show consistent results with the advection-dominated accretion flow (l ∝ dot{m}^2) where the accretion is inefficient and the spectrum is hard (α ˜ 1).
International Nuclear Information System (INIS)
Three different internal mixing methods (Core–Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20–70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20–50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core–Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC–sulfate aerosol is about –3.18 W/m2 for the external method and –6.91 W/m2 for the internal methods at the surface, and –3.03/–1.56/–1.85 W/m2 for the external/Core–Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause. - Highlights: • The aerosol optical properties with different mixing methods
Ruangsri, Uchupol; Hughes, Scott A
2015-01-01
A small body orbiting a black hole follows a trajectory that, at leading order, is a geodesic of the black hole spacetime. Much effort has gone into computing "self force" corrections to this motion, arising from the small body's own contributions to the system's spacetime. Another correction to the motion arises from coupling of the small body's spin to the black hole's spacetime curvature. Spin-curvature coupling drives a precession of the small body, and introduces a "force" (relative to the geodesic) which shifts the small body's worldline. These effects scale with the small body's spin at leading order. If the smaller body is itself a black hole, this means spin-curvature effects scale as the small body's mass squared, the same mass scaling as the self force. In this paper, we show that the equations which govern spin-curvature coupling can be analyzed with a frequency-domain decomposition, at least to leading order in the small body's spin. We show how to compute the frequency of precession along generi...
International Nuclear Information System (INIS)
Stereotactic body radiation therapy (SBRT) is a radiation technique used in patients with oligometastatic lung disease. Lung and chest wall toxicities have been described in the patients but pathological vertebral fracture is an adverse effect no reported in patients treated with SBRT for lung metastases. A 68-year-old woman with the diagnosis of a recurrence of a single lung metastatic nodule of urothelial carcinoma after third line of chemotherapy. The patient received a hypo-fractionated course of SBRT.A 3D-conformal multifield technique was used with six coplanar and one non-coplanar statics beams. A total dose of 48 Gy in three fractions over six days was prescribed to the 95% of the CTV. Ten months after the SBRT procedure, a CT scan showed complete response of the metastatic disease without signs of radiation pneumonitis. However, rib and vertebral bone toxicities were observed with the fracture-collapse of the 7th and 8th vertebral bodies and a fracture of the 7th and 8th left ribs. We report a unique case of pathological vertebral fracture appearing ten months after SBRT for an asymptomatic growing lung metastases of urothelial carcinoma. Though SBRT allows for minimization of normal tissue exposure to high radiation doses SBRT tolerance for vertebral bone tissue has been poorly evaluated in patients with lung tumors. Oncologists should be alert to the potential risk of fatal bone toxicity caused by this novel treatment. We recommend BMD testing in all woman over 65 years old with clinical risk factors that could contribute to low BMD. If low BMD is demonstrated, we should carefully restrict the maximum radiation dose in the vertebral body in order to avoid intermediate or low radiation dose to the whole vertebral body
Rheeder, P; Stolk, RP; Veenhouwer, JF; Grobbee, DE
2002-01-01
Objective. To examine the association between measures of. obesity and features of the metabolic syndrome in treated. black female hypertensive subjects. Design. Cross-sectional study. Setting. An urban primary health care centre in Mamelodi, Pretoria. Subjects. Women with hypertension and without k
Risks of exposure to ionizing and millimeter-wave radiation from airport whole-body scanners.
Moulder, John E
2012-06-01
Considerable public concern has been expressed around the world about the radiation risks posed by the backscatter (ionizing radiation) and millimeter-wave (nonionizing radiation) whole-body scanners that have been deployed at many airports. The backscatter and millimeter-wave scanners currently deployed in the U.S. almost certainly pose negligible radiation risks if used as intended, but their safety is difficult-to-impossible to prove using publicly accessible data. The scanners are widely disliked and often feared, which is a problem made worse by what appears to be a veil of secrecy that covers their specifications and dosimetry. Therefore, for these and future similar technologies to gain wide acceptance, more openness is needed, as is independent review and regulation. Publicly accessible, and preferably peer-reviewed evidence is needed that the deployed units (not just the prototypes) meet widely-accepted safety standards. It is also critical that risk-perception issues be handled more competently. PMID:22494369
Dust and Black Carbon Radiative Forcing Controls on Snowmelt in the Colorado River Basin
Skiles, Sara McKenzie
Light absorbing impurities (LAIs), like dust and black carbon (BC), initiate powerful albedo feedbacks when deposited on snow cover, yet due to a scarcity of observations radiative forcing by LAIs is often neglected, or poorly constrained, in climate and hydrological models. This has important consequences for regions like the Colorado River Basin, where dust deposition to mountain snow cover frequently occurs in the upper basin in the springtime, a relatively new phenomenon since western expansion of the US. Previous work showed that dust on snow (DOS) enhances snowmelt by 3-7 weeks, shifts timing and intensity of runoff, and reduces total water yield. Here, advanced methods are presented to measure, model, and monitor DOS in the hydrologically sensitive Colorado River Basin. A multi-year multi-site spatial variability analysis indicates the heaviest dust loading comes from point sources in the southern Colorado Plateau, but also shows that lower levels of dust loading from diffuse sources still advances melt by 3-4 weeks. A high-resolution snow property dataset, including vertically resolved measurements of snow optical grain size and dust/BC concentrations, confirms that impurity layers remain in the layer in which they are deposited and converge at the surface as snow melts: influencing snow properties, rapidly reducing snow albedo, and increasing snowmelt rates. The optical properties of deposited impurities, which are mainly dust, are determined using an inversion technique from measurements of hemispherical reflectance and particle size distributions. Using updated optical properties in the snow+aerosols radiative transfer model SNICAR improves snow albedo modeling over a more general dust characterization, reducing errors by 50% across the full range of snow reflectance. Radiative forcing by LAIs in the CRB, estimated directly from measurements and updated optical properties, is most strongly controlled by dust concentrations in the uppermost surface layer
Institute of Scientific and Technical Information of China (English)
马志敏; 孙耀; 张波; 唐启升
2004-01-01
Standard metabolic rates of Schlegels black rockfish with different body weights are determined in laboratory by using the flow-through respirometer at 11.2 ℃, 14.7 ℃, 18.0℃ and 23.6 ℃. The results indicate that the standard metabolic rates increase with the increase of body weight at different temperatures. Relationship between them could be described as Rs = a InW b. The mean of standard metabolic rate is significantly different among groups, but the b values are not. The standard metabolic rates of amended standard body weights decrease with the increase of temperature, and the mean of standard metabolic rate is also significantly different among groups when the standard body weights are 48.6 g, 147.9 g, and 243.1 g.Relationship between them could be described as Rsw = me-bT . The relations of standard metabolic rate ( Rs ) or relative metabolic rate ( Rs ) to body weight and temperature yield the following equations: Rs = 1.160 W0.752 e-9.494/7 and Rs1= 1.160 W0.254e-9.494/7.
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper,we extend fermions tunneling radiation to the case of five-dimensional charged black holes by introducing a set of appropriate matrices γμ for general covariant Dirac equation of 1/2 spin charged Dirac particles in the electromagnetic field.It is expected that our result can strengthen the validity and power of the tunneling method.We take the charged Gdel black holes in minimal five-dimensional gauged supergravity for example in order to present a reasonable extension of the tunneling method.As a result,we get fermions tunneling probability of the black hole and the Hawking temperature near the event horizon.
Acute Radiation Syndrome Severity Score System in Mouse Total-Body Irradiation Model.
Ossetrova, Natalia I; Ney, Patrick H; Condliffe, Donald P; Krasnopolsky, Katya; Hieber, Kevin P
2016-08-01
Radiation accidents or terrorist attacks can result in serious consequences for the civilian population and for military personnel responding to such emergencies. The early medical management situation requires quantitative indications for early initiation of cytokine therapy in individuals exposed to life-threatening radiation doses and effective triage tools for first responders in mass-casualty radiological incidents. Previously established animal (Mus musculus, Macaca mulatta) total-body irradiation (γ-exposure) models have evaluated a panel of radiation-responsive proteins that, together with peripheral blood cell counts, create a multiparametic dose-predictive algorithm with a threshold for detection of ~1 Gy from 1 to 7 d after exposure as well as demonstrate the acute radiation syndrome severity score systems created similar to the Medical Treatment Protocols for Radiation Accident Victims developed by Fliedner and colleagues. The authors present a further demonstration of the acute radiation sickness severity score system in a mouse (CD2F1, males) TBI model (1-14 Gy, Co γ-rays at 0.6 Gy min) based on multiple biodosimetric endpoints. This includes the acute radiation sickness severity Observational Grading System, survival rate, weight changes, temperature, peripheral blood cell counts and radiation-responsive protein expression profile: Flt-3 ligand, interleukin 6, granulocyte-colony stimulating factor, thrombopoietin, erythropoietin, and serum amyloid A. Results show that use of the multiple-parameter severity score system facilitates identification of animals requiring enhanced monitoring after irradiation and that proteomics are a complementary approach to conventional biodosimetry for early assessment of radiation exposure, enhancing accuracy and discrimination index for acute radiation sickness response categories and early prediction of outcome. PMID:27356057
Bulk and Brane Decay of a (4+n)-Dimensional Schwarzschild-De-Sitter Black Hole: Scalar Radiation
Kanti, P; Barrau, A
2005-01-01
In this paper, we extend the idea that the spectrum of Hawking radiation can reveal valuable information on a number of parameters that characterize a particular black hole background - such as the dimensionality of spacetime and the value of coupling constants - to gain information on another important aspect: the curvature of spacetime.We investigate the emission of Hawking radiation from a D-dimensional Schwarzschild-de-Sitter black hole emitted in the form of scalar fields, and employ both analytical and numerical techniques to calculate greybody factors and differential energy emission rates on the brane and in the bulk. The energy emission rate of the black hole is enhanced with the number of spacelike dimensions and value of cosmological constant, with the latter parameter leaving a clear footprint in the low-energy regime, through a characteristic constant emission rate of ultra-soft quanta, and the former governing the high-energy part of the spectrum. Our results are applicable to "small" black hole...
Aarseth, Sverre J
2007-01-01
We describe efforts over the last six years to implement regularization methods suitable for studying one or more interacting black holes by direct N-body simulations. Three different methods have been adapted to large-N systems: (i) Time-Transformed Leapfrog, (ii) Wheel-Spoke, and (iii) Algorithmic Regularization. These methods have been tried out with some success on GRAPE-type computers. Special emphasis has also been devoted to including post-Newtonian terms, with application to moderately massive black holes in stellar clusters. Some examples of simulations leading to coalescence by gravitational radiation will be presented to illustrate the practical usefulness of such methods.
Observable signatures of a black hole ejected by gravitational-radiation recoil in a galaxy merger.
Loeb, Abraham
2007-07-27
According to recent simulations, the coalescence of two spinning black holes (BHs) could lead to a BH remnant with recoil speeds of up to thousands of km s(-1). Here we examine the circumstances resulting from a gas-rich galaxy merger under which the ejected BH would carry an accretion disk and be observable. As the initial BH binary emits gravitational radiation and its orbit tightens, a hole is opened in the disk which delays the consumption of gas prior to the eventual BH ejection. The punctured disk remains bound to the ejected BH within the region where the gas orbital velocity is larger than the ejection speed. For a approximately 10(7) M[middle dot in circle] BH the ejected disk has a characteristic size of tens of thousands of Schwarzschild radii and an accretion lifetime of approximately 10(7) yr. During that time, the ejected BH could traverse a considerable distance and appear as an off-center quasar with a feedback trail along the path it left behind. PMID:17678347
Aflatoxins and ochratoxin a reduction in black and white pepper by gamma radiation
International Nuclear Information System (INIS)
Irradiation is an important means of decontamination of food commodities, especially spices. The aim of the current study was to investigate the efficacy of gamma radiation (60Co) for decontaminating ochratoxin A (OTA) and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) residues in artificially contaminated black and white pepper samples. The moisture content of the pepper samples was set at 12% or 18%, and the applied gamma dose ranged from 5 to 30 kGy. Mycotoxin levels were determined by high-performance liquid chromatography (HPLC) after immunoaffinity column (IAC) chromatography. Both the gamma irradiation dose and moisture content showed significant effects (P<0.05) on mycotoxin reduction. The maximum toxin reductions, found at 18% moisture content and 30 kGy, were 55.2%, 50.6%, 39.2%, 47.7% and 42.9% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively. - Highlights: ► The effect of gamma ray on the reduction of AFs and OTA in pepper was investigated. ► The gamma dose and moisture showed significant effects on mycotoxin reduction. ► The maximum reduction was found at 18% moisture content and 30 kGy gamma ray. ► The method, even at 30 kGy and 18% moisture, failed to destroy total of mycotoxins.
Gravitational Lensing Effect on the Hawking Radiation of Dyonic Black Holes
Sakalli, I; Mirekhtiary, S F
2014-01-01
In this paper, we analyze the Hawking radiation (HR) of a non-asymptotically flat (NAF) dyonic black hole (dBH) in four-dimensional (4D) Einstein-Maxwell-Dilaton (EMD) gravity by using one of the semiclassical approaches which is the so-called Hamilton-Jacobi (HJ) method. We particularly motivate on the isotropic coordinate system (ICS) of the dBH in order to highlight the ambiguity to be appeared in the derivation of the Hawking temperature (T_{H}) via the HJ method. Besides, it will be shown that the ICS allows us to write the metric of the dBH in form of the Fermat metric, which renders possible of identification of the refractive index (n) of the dBH. It is shown that the value of n and therefore the gravitational lensing effect is decisive on the the tunneling rate of the HR. We also uncloak how one can resolve the discrepancy about the T_{H} of the dBH in spite of that lensing effect.
Aflatoxins and ochratoxin a reduction in black and white pepper by gamma radiation
Jalili, M.; Jinap, S.; Noranizan, M. A.
2012-11-01
Irradiation is an important means of decontamination of food commodities, especially spices. The aim of the current study was to investigate the efficacy of gamma radiation (60Co) for decontaminating ochratoxin A (OTA) and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) residues in artificially contaminated black and white pepper samples. The moisture content of the pepper samples was set at 12% or 18%, and the applied gamma dose ranged from 5 to 30 kGy. Mycotoxin levels were determined by high-performance liquid chromatography (HPLC) after immunoaffinity column (IAC) chromatography. Both the gamma irradiation dose and moisture content showed significant effects (P<0.05) on mycotoxin reduction. The maximum toxin reductions, found at 18% moisture content and 30 kGy, were 55.2%, 50.6%, 39.2%, 47.7% and 42.9% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively.
N-body modeling of globular clusters: Masses, mass-to-light ratios and intermediate-mass black holes
Baumgardt, H.
2016-10-01
We have determined the masses and mass-to-light ratios of 50 Galactic globular clusters by comparing their velocity dispersion and surface brightness profiles against a large grid of 900 N-body simulations of star clusters of varying initial concentration, size and central black hole mass fraction. Our models follow the evolution of the clusters under the combined effects of stellar evolution and two-body relaxation allowing us to take the effects of mass segregation and energy equipartition between stars self-consistently into account. For a subset of 16 well observed clusters we also derive their kinematic distances. We find an average mass-to-light ratio of Galactic globular clusters of =1.98 ± 0.03, which agrees very well with the expected M/L ratio if the initial mass function (IMF) of the clusters was a standard Kroupa or Chabrier mass function. We do not find evidence for a decrease of the average mass-to-light ratio with metallicity. The surface brightness and velocity dispersion profiles of most globular clusters are incompatible with the presence of intermediate-mass black holes (IMBHs) with more than a few thousand M⊙ in them. The only clear exception is ω Cen, where the velocity dispersion profile provides strong evidence for the presence of a ˜40,000 M⊙ IMBH in the centre of the cluster.
Ciotti, L.; Ostriker, J.P.; Proga, D.
2009-01-01
The importance of the radiative feedback from SMBHs at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole mass and galaxy optical luminosity. In addition, feedback due to mechanical and thermal deposition of energy from jets and winds emitted by the accretion disk around the central SMBH is also expected to occur. In this paper we improve and extend the accretion and feedback physics explored in our previous papers...
Institute of Scientific and Technical Information of China (English)
LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Using anomalous viewpoint,we study the Hawking radiation from a kind of topological Kerr Anti-de-Sitter(Kerr AdS)black hole with ode rotational parameter.We employ the covariant gauge and gravitational anomalies.The result supports the Robinson-Wilczek opinion and shows that the Hawking temperature can be correctly determined by cancelling covariant gauge and gravitational anomalies at the horizon.
"Kludge" gravitational waveforms for a test-body orbiting a Kerr black hole
Babak, S; Gair, J R; Glampedakis, K; Hughes, S A; Babak, Stanislav; Fang, Hua; Gair, Jonathan R.; Glampedakis, Kostas; Hughes, Scott A.
2006-01-01
One of the most exciting potential sources of gravitational waves for low-frequency, space-based gravitational wave (GW) detectors such as the proposed Laser Interferometer Space Antenna (LISA) is the inspiral of compact objects into massive black holes in the centers of galaxies. The detection of waves from such "extreme mass ratio inspiral" systems (EMRIs) and extraction of information from those waves require template waveforms. The systems' extreme mass ratio means that their waveforms can be determined accurately using black hole perturbation theory. Such calculations are computationally very expensive. There is a pressing need for families of approximate waveforms that may be generated cheaply and quickly but which still capture the main features of true waveforms. In this paper, we introduce a family of such "kludge" waveforms and describe ways to generate them. We assess performance of the introduced approximations by comparing "kludge" waveforms to accurate waveforms obtained by solving the Teukolsky...
Marconi, Alessandro; Axon, David J.; Maiolino, Roberto; Nagao, Tohru; Pietrini, Paola; Risaliti, Guido; Robinson, Andrew; Torricelli, Guidetta
2009-01-01
The application of the virial theorem to the broad-line region (BLR) of active galactic nuclei (AGNs) allows black hole (BH) mass estimates for large samples of objects at all redshifts. In a recent paper, we showed that ionizing radiation pressure onto BLR clouds affects virial BH mass estimates and we provided empirically calibrated corrections. More recently, a new test of the importance of radiation forces has been proposed: the M-BH-sigma relation has been used to estimate M-BH for a sam...
Institute of Scientific and Technical Information of China (English)
CHEN Shi-Wu; LIU Xiong-Wei; LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Hawking radiation from cosmological horizon and event horizon of the Reissner-Nordstrom de Sitter black hole with a global monopole is studied via a new method that was propounded by Robinson and Wilzek and elaborated by Banerjee and Kulkarni. The results show that the gauge current and energy-momentum tensor fluxes, which required keeping gauge covariance and general coordinate invaxiance at the quantum level in the effective field theory, axe exactly equivalent to those of Hawking radiation from the event horizon and the cosmological horizon, respectively.
Home Bodies and Wanderers: Sympatric Lineages of the Deep-Sea Black Coral Leiopathes glaberrima
Dannise V Ruiz-Ramos; Miles Saunders; Fisher, Charles R.; Baums, Iliana B.
2015-01-01
Colonial corals occur in a wide range of marine benthic habitats from the shallows to the deep ocean, often defining the structure of their local community. The black coral Leiopathes glaberrima is a long-lived foundation species occurring on carbonate outcrops in the Northern Gulf of Mexico (GoM). Multiple color morphs of L. glaberrima grow sympatrically in the region. Morphological, mitochondrial and nuclear ribosomal markers supported the hypothesis that color morphs constituted a single b...
Dose Definition and Physical Dose Evaluation for the Human Body in External Radiation Accidents
International Nuclear Information System (INIS)
For the bone marrow type of radiation sickness, it is possible to describe the injury to whole-body haematopoietic tissue using stem cell dose. In the case of highly non-uniform exposure, an extra-high local dose to certain parts of the body or absorbed dose to critical organs should be additionally described. To obtain objective dosimetric data from objects carried by the irradiated victims, the watch is an easily available accident dosemeter. Watch rubies can be used as thermoluminescence dosemeters, and the watch glass can be used in electron spin resonance dose measurement. (author)
Li, Ke; Liao, Hong; Mao, Yuhao; Ridley, David A.
2016-01-01
We quantify the contributions from five domestic emission sectors (residential, industry, transportation, energy, and biomass burning) and emissions outside of China (non-China) to concentration and direct radiative forcing (DRF) of black carbon (BC) in China for year 2010 using a nested-grid version of the global chemical transport model (GEOS-Chem) coupled with a radiative transfer model. The Hemispheric Transport of Air Pollution (HTAP) anthropogenic emissions of BC for year 2010 are used in this study. Simulated surface-layer BC concentrations in China have strong seasonal variations, which exceed 9 μg m-3 in winter and are about 1-5 μg m-3 in summer in the North China Plain and the Sichuan Basin. Residential sector is simulated to have the largest contribution to surface BC concentrations, by 5-7 μg m-3 in winter and by 1-3 μg m-3 in summer, reflecting the large emissions from winter heating and the enhanced wet deposition during summer monsoon. The contribution from industry sector is the second largest and shows relatively small seasonal variations; the emissions from industry sector contribute 1-3 μg m-3 to BC concentrations in the North China Plain and the Sichuan Basin. The contribution from transportation sector is the third largest, followed by that from biomass burning and energy sectors. The non-China emissions mainly influence the surface-layer concentrations of BC in western China; about 70% of surface-layer BC concentration in the Tibet Plateau is attributed to transboundary transport. Averaged over all of China, the all-sky DRF of BC at the top of the atmosphere (TOA) is simulated to be 1.22 W m-2. Sensitivity simulations show that the TOA BC direct radiative forcings from the five domestic emission sectors of residential, industry, energy, transportation, biomass burning, and non-China emissions are 0.44, 0.27, 0.01, 0.12, 0.04, and 0.30 W m-2, respectively. The domestic and non-China emissions contribute 75% and 25% to BC DRF in China
Black carbon aerosols and their radiative properties in the Pearl River Delta region
Institute of Scientific and Technical Information of China (English)
WU Dui; MAO JieTai; DENG XueJiao; TIE XueXi; ZHANG YuanHang; ZENG LiMin; LI Fei; TAN HaoBo; BI XueYan; HUANG XiaoYing; CHEN Jing; DENG Tao
2009-01-01
The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main resuits are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1-14.8 pg. m-3 and the concentration decreases by about 1 μg. m-3 in average over the four years; It is higher in the dry season with a multi-year mean of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, end a 4-year mean is 8.4 pg. m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 66% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of
Black carbon aerosols and their radiative properties in the Pearl River Delta region
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher
Directory of Open Access Journals (Sweden)
T. C. Bond
2011-02-01
12 additional models. We outline a framework for combining a large number of simple models with a smaller number of enhanced models that have greater complexity. Adjustments for black carbon internal mixing and for regional variability are discussed. Emitting regions with more deep convection have greater model diversity. Our best estimate of global-mean SFP is +1.03 ± 0.52 GJ g^{−1} for direct atmosphere forcing of black carbon, +1.15 ± 0.53 GJ g^{−1} for black carbon including direct and cryosphere forcing, and −0.064 (−0.02, −0.13 GJ g^{−1} for organic matter. These values depend on the region and timing of emission. The lowest OM:BC mass ratio required to produce a neutral effect on top-of-atmosphere direct forcing is 15:1 for any region. Any lower ratio results in positive direct forcing. However, important processes, particularly cloud changes that tend toward cooling, have not been included here.
Global-average SFP for energy-related emissions can be converted to a 100-year GWP of about 740 ± 370 for BC without snow forcing, and 830 ± 440 with snow forcing. 100-year GWP for OM is −46 (−18, −92. Best estimates of atmospheric radiative impact (without snow forcing by black and organic matter are +0.47 ± 0.26 W m^{−2} and −0.17 (−0.07, −0.35 W m^{−2} for BC and OM, respectively, assuming total emission rates of 7.4 and 45 Tg yr^{−1}. Anthropogenic forcing is +0.40 ± 0.18 W m^{−2} and −0.13 (−0.05, −0.25 W m^{−2} for BC and OM, respectively, assuming anthropogenic emission rates of 6.3 and 32.6 Tg yr^{−1}. Black carbon forcing is only 18% higher than that given by the Intergovernmental Panel on Climate Change (IPCC, although the value presented here includes enhanced absorption due to internal mixing.
Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats
Energy Technology Data Exchange (ETDEWEB)
Filipy, R.E.; Lauhala, K.E.; McGee, D.R.; Cannon, W.C.; Buschbom, R.L.; Decker, J.R.; Kuffel, E.G.; Park, J.F.; Ragan, H.A.; Yaniv, S.S.; Scott, B.R.
1989-05-01
Rats were given doses of /sup 60/Co gamma radiation and/or lung burdens of /sup 147/Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Acute mortality and morbidity from inhaled promethium were caused primarily by radiation pneumonitis and pulmonary fibrosis that occurred more than 53 days after exposure. Acute mortality and morbidity from total-body gamma irradiation occurred within 30 days of exposure and resulted from the bone-marrow radiation syndrome. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. 70 refs., 68 figs., 21 tabs.
Stereotactic body radiation therapy for the primary treatment of localized prostate cancer
Oliai, Caspian; Lanciano, Rachelle; Sprandio, Brian; Yang, Jun; Lamond, John; Arrigo, Steven; Good, Michael; Mooreville, Michael; Garber, Bruce; Brady, Luther W.
2012-01-01
Objective The low alpha/beta ratio of prostate cancer suggests that hypofractionated schemes of dose-escalated radiotherapy should be advantageous. We report our experience using stereotactic body radiation therapy (SBRT) for the primary treatment of prostate cancer to assess efficacy and toxicity. Methods From 2007 to 2010, 70 patients (51 % low risk, 31 % intermediate risk, and 17 % high risk) with localized prostate cancer were treated with SBRT using the CyberKnife system. One-third of pa...
Hawking radiation of scalars from accelerating and rotating black holes with NUT parameter
Jan, Khush; Gohar, H.
2014-03-01
We study the quantum tunneling of scalars from charged accelerating and rotating black hole with NUT parameter. For this purpose we use the charged Klein-Gordon equation. We apply WKB approximation and the Hamilton-Jacobi method to solve charged Klein-Gordon equation. We find the tunneling probability of outgoing charged scalars from the event horizon of this black hole, and hence the Hawking temperature for this black hole
Hawking radiation of scalars from charged accelerating and rotating black holes with NUT parameter
Jan, Khush
2013-01-01
We study the quantum tunneling of scalars from charged accelerating and rotating black hole with NUT parameter. For this purpose we use the charged Klein-Gordon equation. We apply WKB approximation and the Hamilton-Jacobi method to solve charged the Klein-Gordon equation. We find the tunneling probability of outgoing charged scalars from the event horizon of this black hole, and hence the Hawking temperature for this black hole.
Hawking Tunneling Radiation of Black Holes in Deformed H(o)rava-Lifshitz Gravity*
Institute of Scientific and Technical Information of China (English)
ZENG Xiao-Xiong; LI Ling
2011-01-01
Tunneling of scalar particles and Dirac particles from a black hole in the deformed H(o)rava-Lifshitz gravity is discussed in this paper. We consider the case that the dynamical coupling constant λ = 1, when it reduces to Einstein's General Relativity at large scales and the black hole behaves like the Reissner-Nordstr(o)m black hole. The result shows that though the black hole entropy bears logarithmic correction, the tunneling probability is still related to its differences for the scalar particles and Dirac particles.
Zhang, Fan
2013-01-01
At the beginning of binary black hole simulations, there is a pulse of spurious radiation (or junk radiation) resulting from the initial data not matching astrophysical quasi-equilibrium inspiral exactly. One traditionally waits for the junk radiation to exit the computational domain before taking physical readings, at the expense of throwing away a segment of the evolution, and with the hope that junk radiation exits cleanly. We argue that this hope does not necessarily pan out as junk radiation could excite long-lived constraint violation. Another complication with the initial data is that it contains orbital eccentricity that needs to be removed, usually by evolving the early part of the inspiral multiple times with gradually improved input parameters. We show that this procedure is also adversely impacted by junk radiation. In this paper, we do not attempt to eliminate junk radiation directly, but instead tackle the much simpler problem of ameliorating its long-lasting effects. We report on the success of...
Body potassium content and 40K radiation dose to Iranian subjects
International Nuclear Information System (INIS)
In this study 215 Iranian subjects including 180 males and 35 females were investigated for potassium body contents, its variations with age, weight, body build index, and slenderness, as well as the radiation dose due to 40K. The average total body potassium is 147 ± 22 g for males and 100 ± 16 g for females. The average potassium concentrations for males and females are 1.98 ± 0.34 and 1.60 ± 0.29 g kg-1 body weight, respectively. The potassium content decreases with age for both sexes. The 40K concentration decreases with slenderness in both sexes, particularly in females. The total body potassium increases with body build index for males, while its value is constant for females less than 40 y, and increases for females more than 40 y. The average effective doses due to 40K are 187 ± 32 μSv y-1 for males and 150 ± 27 μSv y-1 for females. (author)
Ruangsri, Uchupol; Vigeland, Sarah J.; Hughes, Scott A.
2016-08-01
A small body orbiting a black hole follows a trajectory that, at leading order, is a geodesic of the black hole spacetime. Much effort has gone into computing "self-force" corrections to this motion, arising from the small body's own contributions to the system's spacetime. Another correction to the motion arises from coupling of the small body's spin to the black hole's spacetime curvature. Spin-curvature coupling drives a precession of the small body, and introduces a "force" (relative to the geodesic) which shifts the small body's worldline. These effects scale with the small body's spin at leading order. In this paper, we show that the equations which govern spin-curvature coupling can be analyzed with a frequency-domain decomposition, at least to leading order in the small body's spin. We show how to compute the frequency of precession along generic orbits, and how to describe the small body's precession and motion in the frequency domain. We illustrate this approach with a number of examples. This approach is likely to be useful for understanding spin coupling effects in the extreme mass ratio limit, and may provide insight into modeling spin effects in the strong field for nonextreme mass ratios.
Body Builder’s Nightmare: Black Market Steroid Injection Gone Wrong: a Case Report
Arad, Ehud; Ben Amotz, Oded
2016-01-01
Summary: In the pursuit of success in sports, some athletes are not deterred by health risks associated with the (mis)use of black market preparations of dubious origin as performance-enhancing agents. Several studies published in the recent years demonstrated that anabolic-androgenic steroids, but also stimulants and growth hormones, are misused by numerous recreational athletes from all over the world. Trenbolone is an anabolic steroid routinely used in the finishing phase of beef production to improve animal performance and feed efficiency. A 35-year-old male patient presented to our plastic surgery clinic after self-intramuscular administration of Trenbolone to the superior gluteal area bilaterally, which led to a full-thickness defect in a cone-like distribution. The wounds underwent surgical debridement and were treated locally with mafenide acetate irrigation and wound dressings. Closure was achieved by secondary intention healing. In this report, we discuss the first documented case of full-thickness skin and subcutaneous tissue necrosis after black market anabolic steroid injection. This illustrates a plastic complication and resolution of a widespread but seldom reported problem.
Dumka, U. C.; Manchanda, R. K.; Sinha, P. R.; Sreenivasan, S.; Moorthy, K. Krishna; Suresh Babu, S.
2013-12-01
Time variability of black carbon (BC) aerosols over different timescales (daily, weekly and annual) is studied over a tropical urban location Hyderabad in India using seven channel portable Aethalometer. The results for the 2-year period (January 2009-December 2010) show a daily-mean BC variability from ~1.00±0.12 μg m-3 to 12.50±3.06 μg m-3, with a remarkable annual pattern of winter high and monsoon low. The BC values maximize during winter (December-January), ~6.67±0.22 μg m-3, and drop during summer (June-August), ~2.36±0.09 μg m-3, which establishes a large seasonal variation. Furthermore, the BC mass concentration exhibits a well-defined diurnal variation, with a morning peak and early afternoon minimum. The magnitude of the diurnal variations is seasonal dependent, which maximizes during the winter months. Air mass back trajectories indicated several different transport pathways, while the concentration weighted trajectory (CWT) analysis reveals that the most important potential sources for BC aerosols are the Indo-Gangetic plain (IGP), central India and some hot spots in Pakistan, Arabian Peninsula and Persian Gulf. The absorbing Ångström exponent (αabs) estimated from the spectral values of absorption coefficient (σabs) ranges from 0.9 to 1.1 indicating high BC/OC ratio typical of fossil fuel origin. The annual average BC mass fraction to composite aerosols is found to be (10±3) % contributing to the atmospheric forcing by (55±10) %. The BC radiative forcing at the atmosphere shows strong seasonal dependency with higher values in winter (33.49±7.01) and spring (31.78±12.89) and moderate in autumn (18.94±6.71) and summer (13.15±1.66). The BC radiative forcing at the top of the atmosphere (TOA) is positive in all months, suggesting an overall heating of the regional climate over Hyderabad.
Barragán, V. M.; Villaluenga, J. P. G.; Izquierdo-Gil, M. A.; Pérez-Cordón, R.
2016-07-01
This paper presents a novel method for determining the temperature of a radiating body. The experimental method requires only very common instrumentation. It is based on the measurement of the stationary temperature of an object placed at different distances from the body and on the application of the energy balance equation in a stationary state. The method allows one to obtain the temperature of an inaccessible radiating body when radiation measurements are not available. The method has been applied to the determination of the filament temperature of incandescent lamps of different powers.
Mason, D.D.; Barboza, P.S.; Ward, D.H.
2007-01-01
We compared body size and mass of the whole body, organs, adipose tissue, and muscles of adult Pacific Black Brant (Branta bernicla nigricans (Lawrence, 1846)) collected concurrently in Alaska and Baja California during the fall, winter, and spring of 2002-2003. Head and tarsal lengths of males were similar between sites and slightly larger for females in Alaska than in Baja California. Brant appear to operate under similar physiological bounds, but patterns of nutrient allocation differ between sites. Birds wintering in Alaska lost similar amounts of adipose tissue during early winter as birds in Baja California gained during late winter before migration. Masses of the body, adipose tissue, and flight muscles during mid-winter were similar between sites. Seasonal adipose tissue deposition may, therefore, equally favor winter residency or long-distance migration. Gonad and liver masses increased in late winter for birds in Alaska but not for those in Baja California, suggesting birds wintering in Baja may delay reproductive development in favor of allocating reserves needed for migration. Phenotypic flexibility allows Brant to use widely divergent wintering sites. The wintering location of Brant likely depends more upon changes in environmental conditions and food availability, than upon physiological differences between the two wintering populations. ?? 2007 NRC.
International Nuclear Information System (INIS)
Every radiation field yields a standard irradiation technique in the application of megavolt-devices. For physical-technical radiation planning the adjustment with the therapy simulator is necessary. The small-field radiation therapy is to plan more easily, if whole-body-computer tomogram sections are available. In large-field radiation therapy those are not needed. This is valid especially for constant fields. In the case of irradiation with telecobalt, movement irradiation are in question, especially when whole body tomogramms are helpful. (DG)
Ciotti, L; Proga, D
2009-01-01
The importance of the radiative feedback from SMBHs at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole mass and galaxy optical luminosity. In addition, feedback due to mechanical and thermal deposition of energy from jets and winds emitted by the accretion disk around the central SMBH is also expected to occur. In this paper we improve and extend the accretion and feedback physics explored in our previous papers to include also a physically motivated mechanical feedback. We study the evolution of an isolated elliptical galaxy with the aid of a high-resolution 1-D hydrodynamical code, where the cooling and heating functions include photoionization and Compton effects, and restricting to models which include only radiative or only mechanical feedback. We confirm that for Eddington ratios above 0.01 both the accretion and radiative output are forced by feedback effects to be in burst mode, so that strong intermittencies are expecte...
Hawking radiation from Elko particles tunnelling across black-strings horizon
da Rocha, R.; Hoff da Silva, J. M.
2014-09-01
We apply the tunnelling method for the emission and absorption of Elko particles in the event horizon of a black-string solution. We show that Elko particles are emitted at the expected Hawking temperature from black strings, but with a quite different signature with respect to the Dirac particles. We employ the Hamilton-Jacobi technique to black-hole tunnelling, by applying the WKB approximation to the coupled system of Dirac-like equations governing the Elko particle dynamics. As a typical signature, different Elko particles are shown to produce the same standard Hawking temperature for black strings. However, we prove that they present the same probability irrespectively of outgoing or ingoing the black-hole horizon. This provides a typical signature for mass-dimension-one fermions, that is different from the mass-dimension-three halves fermions inherent to Dirac particles, as different Dirac spinor fields have distinct inward and outward probability of tunnelling.
Institute of Scientific and Technical Information of China (English)
冯中文; 蒋青权; 李国平; 邓娟
2012-01-01
To research the radiation mechanism of dynamical Kerr-Newman black hole under two different general tortoise coordination transformation. Proved that the body spectrum and energy level of non-thermal radiation are same, but the hawking temperature and restricted area of non-thermal radiation are different.%引入两种不同的广义乌龟变换对Kerr-Newman黑洞辐射性质进行研究,通过比较证明,动态Kerr-Newman黑洞的热谱的形式和非热辐射的交错能级最大值相同,而Hawking温度和非热辐射的粒子禁区有一定的区别.
A Planck-like problem for quantum charged black holes
A. FabbriBologna U. and INFN; Navarro, D. J.; Navarro-Salas, J.
2001-01-01
Motivated by the parallelism existing between the puzzles of classical physics at the beginning of the XXth century and the current paradoxes in the search of a quantum theory of gravity, we give, in analogy with Planck's black body radiation problem, a solution for the exact Hawking flux of evaporating Reissner-Nordstrom black holes. Our results show that when back-reaction effects are fully taken into account the standard picture of black hole evaporation is significantly ...
Pan, Wei-Zhen; Yang, Xue-Jun; Xie, Zhi-Kun
2011-04-01
Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour—Ruffini method. After the tortoise coordinate transformation, the Klein—Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton—Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable.
Energy Technology Data Exchange (ETDEWEB)
Fuerst, Steven V.; /KIPAC, Menlo Park; Mizuno, Yosuke; /USRA, Huntsville; Nishikawa, Ken-Ichi; /USRA, Huntsville /Alabama U., Huntsville; Wu, Kinwah; /Mullard Space Sci.
2007-01-05
We calculate the emission from relativistic flows in black hole systems using a fully general relativistic radiative transfer formulation, with flow structures obtained by general relativistic magneto-hydrodynamic simulations. We consider thermal free-free emission and thermal synchrotron emission. Bright filament-like features protrude (visually) from the accretion disk surface, which are enhancements of synchrotron emission where the magnetic field roughly aligns with the line-of-sight in the co-moving frame. The features move back and forth as the accretion flow evolves, but their visibility and morphology are robust. We propose that variations and drifts of the features produce certain X-ray quasi-periodic oscillations (QPOs) observed in black-hole X-ray binaries.
Institute of Scientific and Technical Information of China (English)
Pan Wei-Zhen; Yang Xue-Jun; Xie Zhi-Kun
2011-01-01
Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour-Ruffini method. After the tortoise coordinate transformation,the Klein-Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable.
Energy Technology Data Exchange (ETDEWEB)
Yoon, Sang Min [Univ. of Ulsan, Seoul (Korea, Republic of). Dept. of Radiation Oncology] (and others)
2006-12-15
The aim of this study was to evaluate the treatment outcomes of stereotactic body radiation therapy for treating primary or metastatic thoracic tumors using a stereotactic body frame. Between January 1998 and February 2004, 101 lesions from 91 patients with thoracic tumors were prospectively reviewed. A dose of 10-12 Gy per fraction was given three to four times over consecutive days to a total dose of 30-48 Gy (median 40 Gy). The overall response rate was 82%, with 20 (22%) complete responses and 55 (60%) partial responses. The one- and two-year local progression free survival rates were 90% and 81%, respectively. The patients who received 48 Gy showed a better local tumor control than those who received less than 48 Gy (Fisher exact test; p=0.004). No pulmonary complications greater than a RTOG toxicity criteria grade 2 were observed. The experience of stereotactic body frame based radiation therapy appears to be a safe and promising treatment modality for the local management of primary or metastatic lung tumors. The optimal total dose, fractionation schedule and treatment volume need to be determined after a further follow-up of these results.
Takahashi, Hiroyuki R.; Ohsuga, Ken; Kawashima, Tomohisa; Sekiguchi, Yuichiro
2016-07-01
Using three-dimensional general relativistic radiation-magnetohydrodynamics simulations of accretion flows around stellar mass black holes, we report that the relatively cold disk (≳ {10}7 {{K}}) is truncated near the black hole. Hot and less dense regions, of which the gas temperature is ≳ {10}9 {{K}} and more than 10 times higher than the radiation temperature (overheated regions), appear within the truncation radius. The overheated regions also appear above as well as below the disk, sandwiching the cold disk, leading to the effective Compton upscattering. The truncation radius is ∼ 30{r}{{g}} for \\dot{M}∼ {L}{{Edd}}/{c}2, where {r}{{g}},\\dot{M},{L}{Edd},c are the gravitational radius, mass accretion rate, Eddington luminosity, and light speed, respectively. Our results are consistent with observations of a very high state, whereby the truncated disk is thought to be embedded in the hot rarefied regions. The truncation radius shifts inward to ∼ 10{r}{{g}} with increasing mass accretion rate \\dot{M}∼ 100{L}{{Edd}}/{c}2, which is very close to an innermost stable circular orbit. This model corresponds to the slim disk state observed in ultraluminous X-ray sources. Although the overheated regions shrink if the Compton cooling effectively reduces the gas temperature, the sandwich structure does not disappear at the range of \\dot{M}≲ 100{L}{{Edd}}/{c}2. Our simulations also reveal that the gas temperature in the overheated regions depends on black hole spin, which would be due to efficient energy transport from black hole to disks through the Poynting flux, resulting in gas heating.
Takahashi, Hiroyuki R.; Ohsuga, Ken; Kawashima, Tomohisa; Sekiguchi, Yuichiro
2016-07-01
Using three-dimensional general relativistic radiation-magnetohydrodynamics simulations of accretion flows around stellar mass black holes, we report that the relatively cold disk (≳ {10}7 {{K}}) is truncated near the black hole. Hot and less dense regions, of which the gas temperature is ≳ {10}9 {{K}} and more than 10 times higher than the radiation temperature (overheated regions), appear within the truncation radius. The overheated regions also appear above as well as below the disk, sandwiching the cold disk, leading to the effective Compton upscattering. The truncation radius is ˜ 30{r}{{g}} for \\dot{M}˜ {L}{{Edd}}/{c}2, where {r}{{g}},\\dot{M},{L}{Edd},c are the gravitational radius, mass accretion rate, Eddington luminosity, and light speed, respectively. Our results are consistent with observations of a very high state, whereby the truncated disk is thought to be embedded in the hot rarefied regions. The truncation radius shifts inward to ˜ 10{r}{{g}} with increasing mass accretion rate \\dot{M}˜ 100{L}{{Edd}}/{c}2, which is very close to an innermost stable circular orbit. This model corresponds to the slim disk state observed in ultraluminous X-ray sources. Although the overheated regions shrink if the Compton cooling effectively reduces the gas temperature, the sandwich structure does not disappear at the range of \\dot{M}≲ 100{L}{{Edd}}/{c}2. Our simulations also reveal that the gas temperature in the overheated regions depends on black hole spin, which would be due to efficient energy transport from black hole to disks through the Poynting flux, resulting in gas heating.
Hawking radiation for non-asymptotically flat dilatonic black holes using gravitational anomaly
Energy Technology Data Exchange (ETDEWEB)
Fabris, J.C. [Universidade Federal do Espirito Santo, Departamento de Fisica, Vitoria, Espirito Santo (Brazil); Marques, G.T. [Universidade Federal Rural da Amazonia-Brazil, ICIBE-LASIC, Belem, Para (Brazil)
2012-12-15
The d-dimensional scalar field action may be reduced, in the background geometry of a black hole, to a two-dimensional effective action. In the near-horizon region, it appears a gravitational anomaly: the energy-momentum tensor of the scalar field is not conserved anymore. This anomaly is removed by introducing a term related to the Hawking temperature of the black hole. Even if the temperature term introduced is not covariant, a gauge transformation may restore the covariance. We apply this method to compute the temperature of the dilatonic non-asymptotically flat black holes. We compare the results with those obtained through other methods. (orig.)
'Kludge' gravitational waveforms for a test-body orbiting a Kerr black hole
International Nuclear Information System (INIS)
One of the most exciting potential sources of gravitational waves for low-frequency, space-based gravitational wave (GW) detectors such as the proposed Laser Interferometer Space Antenna (LISA) is the inspiral of compact objects into massive black holes in the centers of galaxies. The detection of waves from such 'extreme mass ratio inspiral' systems (EMRIs) and extraction of information from those waves require template waveforms. The systems' extreme mass ratio means that their waveforms can be determined accurately using black hole perturbation theory. Such calculations are computationally very expensive. There is a pressing need for families of approximate waveforms that may be generated cheaply and quickly but which still capture the main features of true waveforms. In this paper, we introduce a family of such kludge waveforms and describe ways to generate them. Different kinds of kludges have already been used to scope out data analysis issues for LISA. The models we study here are based on computing a particle's inspiral trajectory in Boyer-Lindquist coordinates, and subsequent identification of these coordinates with flat-space spherical polar coordinates. A gravitational waveform may then be computed from the multipole moments of the trajectory in these coordinates, using well-known solutions of the linearised gravitational perturbation equations in flat space time. We compute waveforms using a standard slow-motion quadrupole formula, a quadrupole/octupole formula, and a fast-motion, weak-field formula originally developed by Press. We assess these approximations by comparing to accurate waveforms obtained by solving the Teukolsky equation in the adiabatic limit (neglecting GW backreaction). We find that the kludge waveforms do extremely well at approximating the true gravitational waveform, having overlaps with the Teukolsky waveforms of 95% or higher over most of the parameter space for which comparisons can currently be made. Indeed, we find these
Energy Technology Data Exchange (ETDEWEB)
Murthy, Rajan [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States); Harris, Paul; Leibel, Rudolph [Columbia University College of Physicians and Surgeons, Department of Medicine, New York, NY (United States); Simpson, Norman; Parsey, Ramin [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); Van Heertum, Ronald [Columbia University College of Physicians and Surgeons, Department of Radiology, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States); Mann, J.J. [Columbia University College of Physicians and Surgeons, Department of Psychiatry, New York, NY (United States); Columbia University College of Physicians and Surgeons, Department of Radiology, New York, NY (United States); New York State Psychiatric Institute, Department of Neuroscience, Division of Brain Imaging, New York, NY (United States)
2008-04-15
Vesicular monoamine transporter type 2 abundance quantified using the radiotracer [{sup 11}C]-dihydrotetrabenazine (DTBZ) has been used to study diagnosis and pathogenesis of dementia and psychiatric disorders in humans. In addition, it may be a surrogate marker for insulin-producing pancreatic beta cell mass, useful for longitudinal measurements using positron emission tomography to track progression of autoimmune diabetes. To support the feasibility of long-term repeated administrations, we estimate the biodistribution and dosimetry of [{sup 11}C]-DTBZ in humans. Five baboon studies were acquired using a Siemens ECAT camera. After transmission scanning, 165-210 MBq of [{sup 11}C]-DTBZ were injected, and dynamic whole body emission scans were conducted. Time-activity data were used to obtain residence times and estimate absorbed radiation dose according to the MIRD model. Most of the injected tracer localized to the liver and the lungs, followed by the intestines, brain, and kidneys. The highest estimated absorbed radiation dose was in the stomach wall. The largest radiation dose from [{sup 11}C]-DTBZ is to the stomach wall. This dose estimate, as well as the radiation dose to other radiosensitive organs, must be considered in evaluating the risks of multiple administrations. (orig.)
International Nuclear Information System (INIS)
Purpose: Our previous study reveals bone marrow transplantation (BMT) recruits host marrow-derived myelomonocytic cells to radiation-injured intestine, enhancing stromal proliferation, leading secondarily to epithelial regeneration. In this study, we propose BMT ameliorates intestinal damage via paracrine mechanisms. Materials and methods: Angiogenic cytokines within the intestinal mucosa of mice after whole body irradiation (WBI) with or without BMT were measured by cytokine array and ELISA. BM conditioned medium (BMCM) with or without treatment with neutralizing antibodies to angiogenic cytokines were continuously infused into mice for three days after radiation. Carrageenan was used to deplete myelomonocytic cells of mice. Results: BMT increased VEGF, bFGF and other angiogenic and chemotactic cytokines in the intestinal mucosa within 24 h after WBI. Infusion of BMCM ameliorated radiation-induced intestinal damage with improved stromal activity and prolonged survival of mice. Neutralization of bFGF, PDGF and other angiogenic cytokines within BMCM abolished the mitigating effect to the intestine. Pretreatment of carrageenan to recipient mice reversed some of the cytokine levels, including VEGF, bFGF and IGF within the intestinal mucosa after BMT. Conclusions: Our result suggests BMT recruits host myelomonocytic cells and enhances intestinal stroma proliferation after radiation by secreting cytokines enhancing angiogenesis and chemotaxis. Host myelomonocytic cells further uplift the paracrine effect to enhance intestinal mucosal recovery.
International Nuclear Information System (INIS)
Vesicular monoamine transporter type 2 abundance quantified using the radiotracer [11C]-dihydrotetrabenazine (DTBZ) has been used to study diagnosis and pathogenesis of dementia and psychiatric disorders in humans. In addition, it may be a surrogate marker for insulin-producing pancreatic beta cell mass, useful for longitudinal measurements using positron emission tomography to track progression of autoimmune diabetes. To support the feasibility of long-term repeated administrations, we estimate the biodistribution and dosimetry of [11C]-DTBZ in humans. Five baboon studies were acquired using a Siemens ECAT camera. After transmission scanning, 165-210 MBq of [11C]-DTBZ were injected, and dynamic whole body emission scans were conducted. Time-activity data were used to obtain residence times and estimate absorbed radiation dose according to the MIRD model. Most of the injected tracer localized to the liver and the lungs, followed by the intestines, brain, and kidneys. The highest estimated absorbed radiation dose was in the stomach wall. The largest radiation dose from [11C]-DTBZ is to the stomach wall. This dose estimate, as well as the radiation dose to other radiosensitive organs, must be considered in evaluating the risks of multiple administrations. (orig.)
Motions of Kepler circumbinary planets in restricted three-body problem under radiating primaries
Energy Technology Data Exchange (ETDEWEB)
Dermawan, B., E-mail: budider@as.itb.ac.id; Hidayat, T., E-mail: taufiq@as.itb.ac.id [Astronomy Research Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132 (Indonesia); Huda, I. N., E-mail: ibnu.nurul@students.itb.ac.id; Mandey, D., E-mail: mandey.de@gmail.com; Utama, J. A., E-mail: judhistira@yahoo.com; Tampubolon, I., E-mail: ihsan.tampubolon@gmail.com [Department of Astronomy, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132 (Indonesia); Wibowo, R. W., E-mail: ridlo.w.wibowo@gmail.com [Department of Computational Science, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jalan Ganesha 10, Bandung 40132 (Indonesia)
2015-09-30
By observing continuously a single field of view in the sky, Kepler mission reveals outstanding results on discoveries of exoplanets. One of its recent progress is the discoveries of circumbinary planets. A circumbinary planet is an exoplanet that moves around a binary system. In this study we investigate motions of Kepler circumbinary planets belong to six binary systems, namely Kepler-16, -34, -35, -38, -47, and -413. The motions are considered to follow the Restricted Three-Body Problem (RTBP). Because the primaries (central massive objects) are stars, they are both radiatives, while the planet is an infinitesimal object. The primaries move in nearly circular and elliptic orbits with respect to their center of masses. We describe, in general, motions of the circumbinary planets in RTBP under radiating primaries. With respect to the averaged zero velocity curves, we show that motions of the exoplanets are stable, in accordance with their Hill stabilities.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Rudong; Wang, Hailong; Qian, Yun; Rasch, Philip J.; Easter, Richard C.; Ma, Po-Lun; Singh, Balwinder; Huang, Jianping; Fu, Qiang
2015-01-01
Black carbon (BC)particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source-receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fate of BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation of the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source- receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on seasons and the locations in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in Himalayas and Central Tibetan Plateau, while East Asia FF and BB contribute the most to Northeast Plateau in all seasons and Southeast Plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching Northwest Plateau, especially in the summer. Although the HTP local emissions only contribute about 10% of BC in
N-body modeling of globular clusters: Masses, mass-to-light ratios and intermediate-mass black holes
Baumgardt, Holger
2016-01-01
We have determined the masses and mass-to-light ratios of 50 Galactic globular clusters by comparing their velocity dispersion and surface brightness profiles against a large grid of 900 N-body simulations of star clusters of varying initial concentration, size and central black hole mass fraction. Our models follow the evolution of the clusters under the combined effects of stellar evolution and two-body relaxation allowing us to take the effects of mass segregation and energy equipartition between stars self-consistently into account. For a subset of 16 well observed clusters we also derive their kinematic distances. We find an average mass-to-light ratio of Galactic globular clusters of $=1.98 \\pm 0.03$, which agrees very well with the expected M/L ratio if the initial mass function of the clusters was a standard Kroupa or Chabrier mass function. We do not find evidence for a decrease of the average mass-to-light ratio with metallicity. The surface brightness and velocity dispersion profiles of most globul...
Massive particles' tunnelling radiation from the black hole with a mass-quadruple moment
Institute of Scientific and Technical Information of China (English)
Han Yi-Wen
2007-01-01
In this paper, we extend Zhang and Zhao's recent work to the black hole with a mass-quadruple moment. The behaviour of the tunnelling massive particles is investigated, and the emission rate at which massive particles tunnel across the event horizon of the black hole is calculated. The result is consistent with an underlying unitary theory, and takes the same functional form as that of a massless particle.
Finite width of the sonic event horizon and grey body Hawking radiation
Vinish, Y
2014-01-01
Finite width of the analog event horizon is determined by the nonlinearity length in the Kerr nonlinear optical system, which is discussed here, or by the healing length in Bose-Einstein condensates. The various eigen modes of fluctuations are found in the immediate vicinity of the event horizon and the scattering matrix due to the finite width horizon is calculated to within the leading order correction in the nonlinearity length. The Hawking radiation is found to be that of a grey body with the emissivity larger than one. A procedure of paraxial quantization of the fluctuation field is discussed and its connection to the conventional quantization of the electromagnetic field is demonstrated.
Radiative characteristics of ice-covered fresh- and brackish-water bodies
Leppäranta, Matti; Erm, Ants; Arst, Helgi; Reinart, Anu
2006-01-01
The structure and optics of ice and snow overlying bodies of water were studied in the years 2000–2003. The data were collected in the northern temperate region (nine Estonian and Finnish lakes and one brackish water site, Santala Bay, in the Gulf of Finland). In the present paper we describe the results concerning the radiative characteristics of the system “snow + ice cover on the water”: albedo, attenuation of light, and planar and scalar irradiances through the ice. The basic data consist...
A new treatment of radiation behaviour beyond one-body observables
Energy Technology Data Exchange (ETDEWEB)
Koji, Niita [Reasearch Organization for Information Science anf Technology (RIST), Tokai, Naka, Ibaraki (Japan); Yosuke, Iwamoto; Tatsuhiko, Sato; Norihiro, Matsuda; Yukio, Sakamoto; Hiroshi, Nakashima [Japan Atomic Energy Agency (JAEA), Tokai, Naka, Ibaraki (Japan); Hiroshi, Iwase [High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki (Japan)
2008-07-01
We propose a new treatment of radiation behaviour in transport calculations by introducing an event generator model in which we combine the nuclear data and the reaction models so as to trace all correlations of ejected particles keeping the energy and momentum conservation in a collision. By this new model, we can estimate the fluctuations around the mean values of one-body observables, for example, the deposit energy distribution in a cell, which cannot be obtained by the transport calculations based on the Boltzmann equation with the nuclear data. (authors)
Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer.
Aridgides, Paul; Bogart, Jeffrey
2016-08-01
Stereotactic body radiation therapy (SBRT) has had a profound impact on the treatment paradigm for medically inoperable patients with stage I non-small cell lung cancer. Local control and survival outcomes from prospective collaborative trials using SBRT have been highly favorable in this challenging patient population. Further study in medically operable patients is ongoing; however, randomized trials to help answer this question have terminated early because of poor accrual. Available prospective and retrospective data are discussed for the use of SBRT with regard to the medically inoperable and operable patient populations, as well as considerations for fractionation, dose, and toxicity. PMID:27427521
Casal, J; Arias, J M; Gómez-Camacho, J
2016-01-01
A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly-bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of $B(E1)$ distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to $^{11}$Li ($^{9}$Li+n+n) and $^6$He ($^{4}$He+n+n) three-body systems for which some data exist.
Radiation and diffraction analysis of a cylindrical body with a moon pool
Institute of Scientific and Technical Information of China (English)
ZHOU Hua-wei; ZHANG Hong-sheng
2013-01-01
An analytical solution is presented for the radiation and the diffraction of a cylindrical body with a moon pool floating on the surface of water with a finite depth.The expressions for the potentials are obtained by the method of separation of variables,and the unknown coefficients are determined by the boundary conditions and the matching requirements on the interface.The effects of the moon pool on the hydrodynamic characteristics of the body are investigated.Some peaks are observed on the curves of the added mass and damping coefficients,corresponding to the resonant frequencies of the moon pool.The internal free surface moves like a piston at a certain low resonant frequency.
Oliver, Paul M; Skipwith, Phillip; Lee, Michael S Y
2014-10-01
The region between the Asian and Australian continental plates (Wallacea) demarcates the transition between two differentiated regional biotas. Despite this striking pattern, some terrestrial lineages have successfully traversed the marine barriers of Wallacea and subsequently diversified in newly colonized regions. The hypothesis that these dispersals between biogeographic realms are correlated with detectable shifts in evolutionary trajectory has however rarely been tested. Here, we analyse the evolution of body size in a widespread and exceptionally diverse group of gekkotan lizards (Cyrtodactylus), and show that a clade that has dispersed eastwards and radiated in the Australopapuan region appears to have significantly expanded its body size 'envelope' and repeatedly evolved gigantism. This pattern suggests that the biotic composition of the proto-Papuan Archipelago provided a permissive environment in which new colonists were released from evolutionary constraints operating to the west of Wallacea.
Casal, J.; Rodríguez-Gallardo, M.; Arias, J. M.; Gómez-Camacho, J.
2016-04-01
A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of B (E 1 ) distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to 11Li (9Li+n +n ) and 6He (4He+n +n ) three-body systems for which some data exist.
Barnard, J. C.; E. I. Kassianov; Ackerman, T. P.; K. Johnson; Zuberi, B.; L. T. Molina; M. J. Molina
2007-01-01
During the Mexico City Metropolitan Area (MCMA) field campaign of 2003, measurements of the shortwave radiation field allowed the inference of the black carbon (BC) specific absorption, αλ, defined as the monochromatic absorption cross section per unit mass (with units of m2/g). The averaged values of αλ derived from the method here are either 8.9 m2/g or 8.2 m2/g at 500 nm, depending upon the physical and optical parameters assumed for BC. These re...
Barnard, J. C.; E. I. Kassianov; Ackerman, T. P.; K. Johnson; Zuberi, B.; L. T. Molina; M. J. Molina
2007-01-01
During the Mexico City Metropolitan Area (MCMA) field campaign of 2003, measurements of the shortwave radiation field allowed the inference of the black carbon (BC) specific absorption, αλ, defined as the monochromatic absorption cross section per unit mass (with units of m2/g). The averaged values of αλ derived from the method here are either 8.9 m2/g or 8.2 m2/g at 500 nm, depending upon the physical and optical parameters assumed for BC. These results are reasonab...
Institute of Scientific and Technical Information of China (English)
SUN Run-jun; LAI Kan; ZHANG Jian-chun; HUO Yan
2004-01-01
With the help of the testing apparatus made by ourselves for shielding electromagnetic radiation, the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene film contained different content of carbon particles was systematically studied in this paper. The results indicate that the electric conductivity and shielding effectiveness of electromagnetic radiation of polyethylene /carbon film have closely relations with content of carbon black particles, which exists a critical content value as 14%～30% and its properties will have a tremendous change.
Distribution of Bacteria Injected in Body of Giant Black Shrimp, Penaeus Monodon
Institute of Scientific and Technical Information of China (English)
GUO Zhixun(郭志勋); Karin van de Braak; Magriet Botterbloom
2004-01-01
Distribution of injected Vibrio anguillarum in body of Penaeus monodon was studied with immunohistochemical method. Bacteria could be detected throughout the experiment in some individuals; however in lymphoid tissue, gill, heart and haemolymph of all vibrio injected shrimp, the bacteria could be observed only 5 min after injection. The bacteria density in haemolymph, haemolymph of the hepatopancreas and gills decreased with time. In the lymphoid organ and heart, the bacteria density was the highest 48 h after injection, then decreased. Nodules could be formed in the heart, lymphoid organ and injection site.
Home Bodies and Wanderers: Sympatric Lineages of the Deep-Sea Black Coral Leiopathes glaberrima.
Directory of Open Access Journals (Sweden)
Dannise V Ruiz-Ramos
Full Text Available Colonial corals occur in a wide range of marine benthic habitats from the shallows to the deep ocean, often defining the structure of their local community. The black coral Leiopathes glaberrima is a long-lived foundation species occurring on carbonate outcrops in the Northern Gulf of Mexico (GoM. Multiple color morphs of L. glaberrima grow sympatrically in the region. Morphological, mitochondrial and nuclear ribosomal markers supported the hypothesis that color morphs constituted a single biological species and that colonies, regardless of color, were somewhat genetically differentiated east and west of the Mississippi Canyon. Ten microsatellite loci were used to determine finer-scale population genetic structure and reproductive characteristics. Gene flow was disrupted between and within two nearby (distance = 36.4 km hardground sites and two sympatric microsatellite lineages, which might constitute cryptic species, were recovered. Lineage one was outbred and found in all sampled locations (N = 5 across 765.6 km in the Northern Gulf of Mexico. Lineage two was inbred, reproducing predominantly by fragmentation, and restricted to sites around Viosca Knoll. In these sites the lineages and the color phenotypes occurred in different microhabitats, and models of maximum entropy suggested that depth and slope influence the distribution of the color phenotypes within the Vioska Knolls. We conclude that L. glaberrima is phenotypically plastic with a mixed reproductive strategy in the Northern GoM. Such strategy might enable this long-lived species to balance local recruitment with occasional long-distance dispersal to colonize new sites in an environment where habitat is limited.
Home Bodies and Wanderers: Sympatric Lineages of the Deep-Sea Black Coral Leiopathes glaberrima.
Ruiz-Ramos, Dannise V; Saunders, Miles; Fisher, Charles R; Baums, Iliana B
2015-01-01
Colonial corals occur in a wide range of marine benthic habitats from the shallows to the deep ocean, often defining the structure of their local community. The black coral Leiopathes glaberrima is a long-lived foundation species occurring on carbonate outcrops in the Northern Gulf of Mexico (GoM). Multiple color morphs of L. glaberrima grow sympatrically in the region. Morphological, mitochondrial and nuclear ribosomal markers supported the hypothesis that color morphs constituted a single biological species and that colonies, regardless of color, were somewhat genetically differentiated east and west of the Mississippi Canyon. Ten microsatellite loci were used to determine finer-scale population genetic structure and reproductive characteristics. Gene flow was disrupted between and within two nearby (distance = 36.4 km) hardground sites and two sympatric microsatellite lineages, which might constitute cryptic species, were recovered. Lineage one was outbred and found in all sampled locations (N = 5) across 765.6 km in the Northern Gulf of Mexico. Lineage two was inbred, reproducing predominantly by fragmentation, and restricted to sites around Viosca Knoll. In these sites the lineages and the color phenotypes occurred in different microhabitats, and models of maximum entropy suggested that depth and slope influence the distribution of the color phenotypes within the Vioska Knolls. We conclude that L. glaberrima is phenotypically plastic with a mixed reproductive strategy in the Northern GoM. Such strategy might enable this long-lived species to balance local recruitment with occasional long-distance dispersal to colonize new sites in an environment where habitat is limited. PMID:26488161
Avkshtol, Vladimir; Dong, Yanqun; Hayes, Shelly B; Hallman, Mark A; Price, Robert A; Sobczak, Mark L; Horwitz, Eric M; Zaorsky, Nicholas G
2016-01-01
Prostate cancer is the most prevalent cancer diagnosed in men in the United States besides skin cancer. Stereotactic body radiation therapy (SBRT; 6–15 Gy per fraction, up to 45 minutes per fraction, delivered in five fractions or less, over the course of approximately 2 weeks) is emerging as a popular treatment option for prostate cancer. The American Society for Radiation Oncology now recognizes SBRT for select low- and intermediate-risk prostate cancer patients. SBRT grew from the notion that high doses of radiation typical of brachytherapy could be delivered noninvasively using modern external-beam radiation therapy planning and delivery methods. SBRT is most commonly delivered using either a traditional gantry-mounted linear accelerator or a robotic arm-mounted linear accelerator. In this systematic review article, we compare and contrast the current clinical evidence supporting a gantry vs robotic arm SBRT for prostate cancer. The data for SBRT show encouraging and comparable results in terms of freedom from biochemical failure (>90% for low and intermediate risk at 5–7 years) and acute and late toxicity (cancer-specific mortality) cannot be compared, given the indolent course of low-risk prostate cancer. At this time, neither SBRT device is recommended over the other for all patients; however, gantry-based SBRT machines have the abilities of treating larger volumes with conventional fractionation, shorter treatment time per fraction (~15 minutes for gantry vs ~45 minutes for robotic arm), and the ability to achieve better plans among obese patients (since they are able to use energies >6 MV). Finally, SBRT (particularly on a gantry) may also be more cost-effective than conventionally fractionated external-beam radiation therapy. Randomized controlled trials of SBRT using both technologies are underway. PMID:27574585
International Nuclear Information System (INIS)
It is known that the nonstrictly thermal character of the Hawking radiation spectrum harmonizes Hawking radiation with black hole (BH) quasi-normal modes (QNM). This paramount issue has been recently analyzed in the framework of both Schwarzschild BHs (SBH) and Kerr BHs (KBH). In this assignment, we generalize the analysis to the framework of nonextremal Reissner-Nordström BHs (RNBH). Such a generalization is important because in both Schwarzschild and Kerr BHs an absorbed (emitted) particle has only mass. Instead, in RNBH the particle has charge as well as mass. In doing so, we expose that, for the RNBH, QNMs can be naturally interpreted in terms of quantum levels for both particle emission and absorption. Conjointly, we generalize some concepts concerning the RNBH's “effective states.”
Umemura, M
2001-01-01
As a potential mechanism to build up supermassive black holes (BHs) in a spheroidal system, we consider the radiation drag effect by bulge stars, which extracts angular momentum from interstellar gas and thus allows the gas to accrete onto the galactic center. With incorporating radiation hydrodynamical equation with simple stellar evolution, it is shown that the BH-to-bulge mass ratio, $f_{BH}$, is basically determined by a fundamental constant, that is, the energy conversion efficiency for nuclear fusion of hydrogen to helium, $\\epsilon=0.007$. More specifically, $f_{BH}$ is predicted to be $0.3\\epsilon -0.5\\epsilon$. Based on the present model for BH growth, a scenario for quasar formation is addressed in relation to ultraluminous infrared galaxies.
Parnell, Mark; Burt, P. J. A.; Wilson, Kate
The influence of ultraviolet (UV) radiation in simulated natural sunlight on the viability of ascospores of Mycosphaerella fijiensis, the cause of Black Sigatoka disease in banana and plantain, has been investigated as part of a study to assess the windborne spread of this pathogen from mainland Central and South America into the Caribbean. Spores were killed following continuous exposure to UV radiation for periods of 6 h or over. This relatively short exposure time suggests that the distances over which viable spores can be transported will be determined not only by the speed of the wind but also the amount of cloud cover and the time off day that spore release occurs. On this basis, wind dispersal of viable spores over distances greater than a few hundred kilometres is unlikely. These conclusions are reinforced by an examination of historical reports of the arrival of the disease in previously uninfected areas of the Americas and Africa.
Directory of Open Access Journals (Sweden)
Devlina Chakarvarty
2010-06-01
Full Text Available Paragangliomas are rare tumors and very few cases of malignant vagal paraganglioma with synchronous carotid body paraganglioma have been reported. We report a case of a 20-year old male who presented with slow growing bilateral neck masses of eight years duration. He had symptoms of dysphagia to solids, occasional mouth breathing and hoarseness of voice. Fine needle aspiration cytology (FNAC performed where he lived showed a sinus histiocytosis and he was administered anti-tubercular treatment for six months without any improvement in his symptoms. His physical examination revealed pulsatile, soft to firm, non-tender swellings over the anterolateral neck confined to the upper-mid jugulo-diagastric region on both sides. Direct laryngoscopy examination revealed a bulge on the posterior pharyngeal wall and another over the right lateral pharyngeal wall. Magnetic resonance imaging (MRI, 99mTc-labeled octreotide scan and angiography diagnosed the swellings as carotid body paraganglioma, stage III on the right side with left-sided vagal malignant paraganglioma. Surgery was ruled out as a high morbidity with additional risk to life was expected due to the highly vascular nature of the tumor. The patient was treated with radiation therapy by image guided radiation to a dose of 5040cGy in 28 fractions. At a follow-up at 16 months, the tumors have regressed bilaterally and the patient can take solids with ease.
Gravitational wave production by Hawking radiation from rotating primordial black holes
Dong, Ruifeng; Kinney, William H.; Stojkovic, Dejan
2016-10-01
In this paper we analyze in detail a rarely discussed question of gravity wave production from evaporating primordial black holes. These black holes emit gravitons which are, at classical level, registered as gravity waves. We use the latest constraints on their abundance, and calculate the power emitted in gravitons at the time of their evaporation. We then solve the coupled system of equations that gives us the evolution of the frequency and amplitude of gravity waves during the expansion of the universe. The spectrum of gravitational waves that can be detected today depends on multiple factors: fraction of the total energy density which was occupied by primordial black holes, the epoch in which they were formed, and quantities like their mass and angular momentum. We conclude that very small primordial black holes which evaporate before the big-bang nucleosynthesis emit gravitons whose spectral energy fraction today can be as large as 10‑7.5. On the other hand, those which are massive enough so that they still exist now can yield a signal as high as 10‑6.5. However, typical frequencies of the gravity waves from primordial black holes are still too high to be observed with the current and near future gravity wave observations.
... product containing black tea extract plus green tea extract, asparagus, guarana, kidney bean, and mate along with a combination of kidney bean pods, garcinia, and chromium yeast for 12 weeks does not reduce body weight ...
Directory of Open Access Journals (Sweden)
Stefano G. Masciullo
2012-11-01
Full Text Available The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID in stereotactic body radiation therapy (SBRT with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT, estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10Gy for tumor tissue and imposing the same biological effective dose (BED on the target (BED = 76Gy10. Total NTIDs for both techniques was calculated considering α/β = 3Gy for healthy tissue. Excess absolute cancer risk (EAR was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05. Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002, secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001. This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged.
International Nuclear Information System (INIS)
Purpose: To differentiate radiation-induced fibrosis from regional lung collapse outside of the high dose region in patients treated with stereotactic body radiation therapy (SBRT) for lung tumors. Methods: Lung deformation maps were computed from pre-treatment and post-treatment computed tomography (CT) scans using a point-to-point translation method. Fifty anatomical landmarks inside the lung (vessel or airway branches) were matched on planning and follow-up scans for the computation process. Two methods using the deformation maps were developed to differentiate regional lung collapse from fibrosis: vector field and Jacobian methods. A total of 40 planning and follow-ups CT scans were analyzed for 20 lung SBRT patients. Results: Regional lung collapse was detected in 15 patients (75%) using the vector field method, in ten patients (50%) using the Jacobian method, and in 12 patients (60%) by radiologists. In terms of sensitivity and specificity the Jacobian method performed better. Only weak correlations were observed between the dose to the proximal airways and the occurrence of regional lung collapse. Conclusions: The authors presented and evaluated two novel methods using anatomical lung deformations to investigate lung collapse and fibrosis caused by SBRT treatment. Differentiation of these distinct physiological mechanisms beyond what is usually labeled “fibrosis” is necessary for accurate modeling of lung SBRT-induced injuries. With the help of better models, it becomes possible to expand the therapeutic benefits of SBRT to a larger population of lung patients with large or centrally located tumors that were previously considered ineligible