1st Karl Schwarzschild Meeting on Gravitational Physics
Kaminski, Matthias; Mureika, Jonas; Bleicher, Marcus
2016-01-01
These proceedings collect the selected contributions of participants of the First Karl Schwarzschild Meeting on Gravitational Physics, held in Frankfurt, Germany to celebrate the 140th anniversary of Schwarzschild's birth. They are grouped into 4 main themes: I. The Life and Work of Karl Schwarzschild; II. Black Holes in Classical General Relativity, Numerical Relativity, Astrophysics, Cosmology, and Alternative Theories of Gravity; III. Black Holes in Quantum Gravity and String Theory; IV. Other Topics in Contemporary Gravitation. Inspired by the foundational principle ``By acknowledging the past, we open a route to the future", the week-long meeting, envisioned as a forum for exchange between scientists from all locations and levels of education, drew participants from 15 countries across 4 continents. In addition to plenary talks from leading researchers, a special focus on young talent was provided, a feature underlined by the Springer Prize for the best student and junior presentations.
Schwarzschild Solution: A Historical Perspective
Bartusiak, Marcia
2016-03-01
While eighteenth-century Newtonians had imagined a precursor to the black hole, the modern version has its roots in the first full solution to Einstein's equations of general relativity, derived by the German astronomer Karl Schwarzschild on a World War I battlefront just weeks after Einstein introduced his completed theory in November 1915. This talk will demonstrate how Schwarzschild's solution is linked to the black hole and how it took more than half a century for the physics community to accept that such a bizarre celestial object could exist in the universe.
Doppleraj efikoj \\^ce Schwarzschild
Paiva, F M
2009-01-01
Motion of bodies and light rays are studied in the gravitational field of Schwarzschild. Several Doppler effects are described. ----- Movado de korpoj kaj lumo estas studitaj en gravita kampo de Schwarzschild. Pluraj Doppleraj efikoj estas priskribitaj.
DEFF Research Database (Denmark)
Jakobsen, Uffe
1988-01-01
For 50 år siden hyldede avisen 'Social-Demokraten' Karl Kautsky (1854-1938) som "den største Tænker inden for den socialdemokratiske Arbejderbevægelse". I perioden fra Friedrich Engels' død i 1895 til 1. Verdenskrigs udbrud i 1914 blev Karl Kautsky alment anset som Karl Marx's arvtager inden for ...
Einstein, Schwarzschild, the Perihelion Motion of Mercury and the Rotating Disk Story
Weinstein, Galina
2014-01-01
On November 18, 1915 Einstein reported to the Prussian Academy that the perihelion motion of Mercury is explained by his new General Theory of Relativity: Einstein found approximate solutions to his November 11, 1915 field equations. Einstein's field equations cannot be solved in the general case, but can be solved in particular situations. The first to offer such an exact solution was Karl Schwarzschild. Schwarzschild found one line element, which satisfied the conditions imposed by Einstein on the gravitational field of the sun, as well as Einstein's field equations from the November 18, 1915 paper. On December 22, 1915 Schwarzschild told Einstein that he reworked the calculation in his November 18 1915 paper of the Mercury perihelion. Subsequently Schwarzschild sent Einstein a manuscript, in which he derived his exact solution of Einstein's field equations. On January 13, 1916, Einstein delivered Schwarzschild's paper before the Prussian Academy, and a month later the paper was published. In March 1916 Ein...
The Schwarzschild's Braneworld Solution
Ovalle, J
2010-01-01
In the context of the Randall-Sundrum braneworld, the minimal geometric deformation approach, which has been successfully used to generate exact interior solutions to Einstein's field equations for static braneworld stars with local and non-local bulk terms, is used to obtain the braneworld version of the Schwarzschild's interior solution. Using this new solution, the behaviour of the Weyl functions is elucidated in terms of the compactness for different stellar distributions.
The Schwarzschild's Braneworld Solution
Ovalle, J.
In the context of the Randall-Sundrum braneworld, the minimal geometric deformation approach, which has been successfully used to generate exact interior solutions to Einstein's field equations for static braneworld stars with local and nonlocal bulk terms, is used to obtain the braneworld version of the Schwarzschild's interior solution. Using this new solution, the behavior of the Weyl functions is elucidated in terms of the compactness for different stellar distributions.
Karl Ristikivi prantsuse keeles
2003-01-01
29. ja 30. mail Tallinna Kirjanike Majas ja 31. mail Tartu Kirjanduse Majas esinevad näitlejad Ene Rämmeld ja Claude Merlin Karl Ristikivi luulekavaga "Inimese teekond" (tõlkija Tarah Montbélialtz). Vt. ka Looming, 2003, nr. 6, lk. 953
Kalevipojad tulevad / Karl Kello
Kello, Karl, 1950-
2004-01-01
Kuressaare Kuursaalis näidatakse kadripäeval nelja Ruta Celma ja Karl Kello kultuuriloolist dokumentaalfilmi : "Narr Jumala kojas" (2000), "Phaetonit otsides" (1999), "Eestlased Lätis" (2004) ja Kalevipoja temaatikat arendav "Küll siis Kalev..." (2004). Filmide operaator on Arvo Vilu. Artikli autor kõneleb ka nende filmide seostest Saaremaaga
Karl Ristikivi prantsuse keeles
2003-01-01
29. ja 30. mail Tallinna Kirjanike Majas ja 31. mail Tartu Kirjanduse Majas esinevad näitlejad Ene Rämmeld ja Claude Merlin Karl Ristikivi luulekavaga "Inimese teekond" (tõlkija Tarah Montbélialtz). Vt. ka Looming, 2003, nr. 6, lk. 953
2006-01-01
Moekunstnik Karl Lagerfeld kaebas kohtusse raamatu "The Beautiful Fall : Fashion, Genius and Glorious Excess in 1970s Paris" autori Alicia Drake'i. Raamat räägib Lagerfeldi noorusajast ja tema konkurentsist moekunstnik Yves Saint Laurent'iga 1970. aastate Pariisis
DEFF Research Database (Denmark)
Eggert, Birgit
2013-01-01
I den danske fornavnemode findes en række navne i flere forskellige stavemåder som ikke har indflydelse på navnenes udtale. Navnene udtales ens hvad enten de staves Carl eller Karl og Camilla eller Kamilla. Med udgangspunkt i de 50 mest populære pige- og drengenavne hvert år siden 1985 har jeg set...
2006-01-01
Moekunstnik Karl Lagerfeld kaebas kohtusse raamatu "The Beautiful Fall : Fashion, Genius and Glorious Excess in 1970s Paris" autori Alicia Drake'i. Raamat räägib Lagerfeldi noorusajast ja tema konkurentsist moekunstnik Yves Saint Laurent'iga 1970. aastate Pariisis
Centennial of General Relativity (1915-2015); The Schwarzschild Solution and Black Holes
Blinder, S M
2015-01-01
This year marks the 100th anniversary of Einstein's General Theory of Relativity (1915-2015). The first nontrivial solution of the Einstein field equations was derived by Karl Schwarzschild in 1916. This Note will focus mainly on the Schwarzschild solution and the remarkable developments which it inspired, the most dramatic being the prediction of black holes. Later extensions of Schwarzschild's spacetime structure has led to even wilder conjectures, such as white holes and passages to other universes. Penrose diagrams are introduced as compact representations of extended spacetime structures. Stephen Hawking's derivations of quantum effects in black holes might provide clues to an eventual "Theory of Everything" encompassing both general relativity and quantum mechanics.
McNamara, D. R.
1978-01-01
Sir Karl Popper is one of England's most distinguished contemporary philosophers and it is surprising that his thought has not permeated and informed educational discussion. This paper suggests that educationists have much to learn from Karl Popper's writings and explores ways in which his ideas can illuminate and advance discussion about…
On a Schwarzschild like metric
Anastasiei, M
2011-01-01
In this short Note we would like to bring into the attention of people working in General Relativity a Schwarzschild like metric found by Professor Cleopatra Mociu\\c{t}chi in sixties. It was obtained by the A. Sommerfeld reasoning from his treatise "Elektrodynamik" but using instead of the energy conserving law from the classical Physics, the relativistic energy conserving law.
Karl Jaspers' multiperspectivalism.
Wiggins, Osborne P; Schwartz, Michael Alan
2013-01-01
In later editions of his General Psychopathology, Karl Jaspers prescribes many different methods and theoretical points of view for psychopathologists to utilize. Each of these perspectives on the subject matter of psychopathology, however, gives the investigator access to only one dimension of the patient's being. Hence, Jaspers insists that several different perspectives must be employed in order to avoid a one-sided and partial comprehension of the patient and his or her problem. He advocates a multiperspectival approach in psychopathology. Nevertheless, Jaspers remains aware that the patient is a unified whole. This unified whole, however, is not knowable as such, but can rather be approached only under the guidance of an 'idea' of the whole. Jaspers takes the basic notion of 'idea' (Idee) from Kant, but he modifies and uses it for his own purposes. Jaspers' multiperspectivalism may seem to invite charges of relativism because it leaves the psychopathologist to 'pick and choose' any method or theory he or she prefers. This charge is addressed by admitting that there does exist a certain relativism in Jaspers' position in that any one perspective does provide only one approach to the reality of the patient and that other equally useful perspectives could have been chosen. However, each perspective itself can be subjected to test by evidence, and in such tests, claims made from that perspective can be found to be true or false. Helen Longino's theory of scientific knowledge helps support such a thesis.
Shields, William
2004-05-01
Karl Popper, though not trained as a physicist and embarrassed early in his career by a physics error pointed out by Einstein and Bohr, ultimately made substantial contributions to the interpretation of quantum mechanics. As was often the case, Popper initially formulated his position by criticizing the views of others - in this case Niels Bohr and Werner Heisenberg. Underlying Popper's criticism was his belief that, first, the "standard interpretation" of quantum mechanics, sometimes called the Copenhagen interpretation, abandoned scientific realism and second, the assertion that quantum theory was "complete" (an assertion rejected by Einstein among others) amounted to an unfalsifiable claim. Popper insisted that the most basic predictions of quantum mechanics should continue to be tested, with an eye towards falsification rather than mere adding of decimal places to confirmatory experiments. His persistent attacks on the Copenhagen interpretation were aimed not at the uncertainty principle itself and the formalism from which it was derived, but at the acceptance by physicists of an unclear epistemology and ontology that left critical questions unanswered. In 1999, physicists at the University of Maryland conducted a version of Popper's Experiment, re-igniting the debate over quantum predictions and the role of locality in physics.
Spectral Properties of Schwarzschild Instantons
Jante, Rogelio
2016-01-01
We study spectral properties of the Dirac and scalar Laplace operator on the Euclidean Schwarzschild space, both twisted by a family of abelian connections with anti-self-dual curvature. We show that the zero-modes of the gauged Dirac operator, first studied by Pope, take a particularly simple form in terms of the radius of the Euclidean time orbits, and interpret them in the context of geometric models of matter. For the gauged Laplace operator, we study the spectrum of bound states numerically and observe that it can be approximated with remarkable accuracy by that of the exactly solvable gauged Laplace operator on the Euclidean Taub-NUT space.
Directory of Open Access Journals (Sweden)
Cecilia Tohăneanu
2014-04-01
Full Text Available Dedicated to Karl Popper’s memory, this essay aims at following the echo of his critical rationalism and how it has been received by Mario Bunge, one of the most prominent contemporary philosopher of science – an admirer, later a critic of Popper’s social and political philosophy. The main goal of such an endeavor is to find out where could have been Popper wrong – from Bunge’s view point – and take note of the arguments of both of them, thus hoping to get closer to the truth, as Sir Karl said.
Sõrmuste isand Karl Fritsch / Merike Alber
Alber, Merike
2008-01-01
Saksa ehtekunstniku Karl Fritschi (sünd. 1963) näitus "Metrosideros robusta. Ehted" Eesti Tarbekunsti- ja Disainimuuseumis kuni 29. VI. Karl Fritsch pälvis 2006. a. Francoise van den Boschi (hollandi ehtekunstnik, 1944-1977) auhinna, 1995. ja 2007. a. Herbert Hoffmanni preemia. Darling Publications kirjastas Karl Fritschist raamatud "Metrosideros Robusta" ja "Baby Brick"
Sõrmuste isand Karl Fritsch / Merike Alber
Alber, Merike
2008-01-01
Saksa ehtekunstniku Karl Fritschi (sünd. 1963) näitus "Metrosideros robusta. Ehted" Eesti Tarbekunsti- ja Disainimuuseumis kuni 29. VI. Karl Fritsch pälvis 2006. a. Francoise van den Boschi (hollandi ehtekunstnik, 1944-1977) auhinna, 1995. ja 2007. a. Herbert Hoffmanni preemia. Darling Publications kirjastas Karl Fritschist raamatud "Metrosideros Robusta" ja "Baby Brick"
Schwarzschild black hole in dark energy background
Ishwarchandra, Ngangbam; Singh, K Yugindro
2014-01-01
In this paper we present an exact solution of Einstein's field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type $D$ in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity...
Karl Ove Knausgaard's My Struggle
DEFF Research Database (Denmark)
Schmitt, Arnaud; Kjerkegaard, Stefan
2016-01-01
In this study of Karl Ove Knausgaard’s My Struggle, the authors theorize what paratextual information does to one’s reading, especially in autobiography informed literature. Although My Struggle can be read both as memoir and novel, and even as autofiction, Knausgaard is aiming at a higher truth...
Karl Marx 1864 og forsigtighedsprincippet
DEFF Research Database (Denmark)
Czeskleba-Dupont, Rolf
2015-01-01
Artiklen analyserer divergerende versioner af den tekst, som Karl Marx efter dannelsen af den 1.Internationale Arbejderassociation i London september 1864 har oversat fra sit engelske original (Inaugural Address...), der udkom i november, til en tysk version med overskriften 'Manifest an die arbe...
The escape velocity and Schwarzschild metric
Murzagalieva, A G; Murzagaliev, G Z
2002-01-01
The escape velocity value in the terms of general relativity by means Schwarzschild metric is provided to make of the motion equation with Friedman cosmological model behavior build in the terms of Robertson-Worker metric. (author)
Rädler, K.-H.
This article elucidates the basic ideas of electrodynamics and magnetohydrodynamics of mean fields in turbulently moving conducting fluids. It is stressed that the connection of the mean electromotive force with the mean magnetic field and its first spatial derivatives is in general neither local nor instantaneous and that quite a few claims concerning pretended failures of the mean-field concept result from ignoring this aspect. In addition to the mean-field dynamo mechanisms of α2 and α Ω type several others are considered. Much progress in mean-field electrodynamics and magnetohydrodynamics results from the test-field method for calculating the coefficients that determine the connection of the mean electromotive force with the mean magnetic field. As an important example the memory effect in homogeneous isotropic turbulence is explained. In magnetohydrodynamic turbulence there is the possibility of a mean electromotive force that is primarily independent of the mean magnetic field and labeled as Yoshizawa effect. Despite of many efforts there is so far no convincing comprehensive theory of α quenching, that is, the reduction of the α effect with growing mean magnetic field, and of the saturation of mean-field dynamos. Steps toward such a theory are explained. Finally, some remarks on laboratory experiments with dynamos are made.
Uncertainty relation in Schwarzschild spacetime
Feng, Jun; Zhang, Yao-Zhong; Gould, Mark D.; Fan, Heng
2015-04-01
We explore the entropic uncertainty relation in the curved background outside a Schwarzschild black hole, and find that Hawking radiation introduces a nontrivial modification on the uncertainty bound for particular observer, therefore it could be witnessed by proper uncertainty game experimentally. We first investigate an uncertainty game between a free falling observer and his static partner holding a quantum memory initially entangled with the quantum system to be measured. Due to the information loss from Hawking decoherence, we find an inevitable increase of the uncertainty on the outcome of measurements in the view of static observer, which is dependent on the mass of the black hole, the distance of observer from event horizon, and the mode frequency of quantum memory. To illustrate the generality of this paradigm, we relate the entropic uncertainty bound with other uncertainty probe, e.g., time-energy uncertainty. In an alternative game between two static players, we show that quantum information of qubit can be transferred to quantum memory through a bath of fluctuating quantum fields outside the black hole. For a particular choice of initial state, we show that the Hawking decoherence cannot counteract entanglement generation after the dynamical evolution of system, which triggers an effectively reduced uncertainty bound that violates the intrinsic limit -log2 c. Numerically estimation for a proper choice of initial state shows that our result is comparable with possible real experiments. Finally, a discussion on the black hole firewall paradox in the context of entropic uncertainty relation is given.
Uncertainty relation in Schwarzschild spacetime
Directory of Open Access Journals (Sweden)
Jun Feng
2015-04-01
Full Text Available We explore the entropic uncertainty relation in the curved background outside a Schwarzschild black hole, and find that Hawking radiation introduces a nontrivial modification on the uncertainty bound for particular observer, therefore it could be witnessed by proper uncertainty game experimentally. We first investigate an uncertainty game between a free falling observer and his static partner holding a quantum memory initially entangled with the quantum system to be measured. Due to the information loss from Hawking decoherence, we find an inevitable increase of the uncertainty on the outcome of measurements in the view of static observer, which is dependent on the mass of the black hole, the distance of observer from event horizon, and the mode frequency of quantum memory. To illustrate the generality of this paradigm, we relate the entropic uncertainty bound with other uncertainty probe, e.g., time–energy uncertainty. In an alternative game between two static players, we show that quantum information of qubit can be transferred to quantum memory through a bath of fluctuating quantum fields outside the black hole. For a particular choice of initial state, we show that the Hawking decoherence cannot counteract entanglement generation after the dynamical evolution of system, which triggers an effectively reduced uncertainty bound that violates the intrinsic limit −log2c. Numerically estimation for a proper choice of initial state shows that our result is comparable with possible real experiments. Finally, a discussion on the black hole firewall paradox in the context of entropic uncertainty relation is given.
Quantum corrected Schwarzschild thin-shell wormhole
Energy Technology Data Exchange (ETDEWEB)
Jusufi, Kimet [State University of Tetovo, Physics Department, Tetovo (Macedonia, The Former Yugoslav Republic of)
2016-11-15
Recently, Ali and Khalil (Nucl Phys B, 909, 173-185, 2016), based on Bohmian quantum mechanics, derived a quantum corrected version of the Schwarzschild metric. In this paper, we construct a quantum corrected Schwarzschild thin-shell wormhole (QSTSW) and investigate the stability of this wormhole. First we compute the surface stress at the wormhole throat by applying the Darmois-Israel formalism to the modified Schwarzschild metric and show that exotic matter is required at the throat to keep the wormhole stable. We then study the stability analysis of the wormhole by considering phantom-energy for the exotic matter, generalized Chaplygin gas (GCG), and the linearized stability analysis. It is argued that quantum corrections can affect the stability domain of the wormhole. (orig.)
Quantum corrected Schwarzschild thin-shell wormhole
Jusufi, Kimet
2016-11-01
Recently, Ali and Khalil (Nucl Phys B, 909, 173-185, 2016), based on Bohmian quantum mechanics, derived a quantum corrected version of the Schwarzschild metric. In this paper, we construct a quantum corrected Schwarzschild thin-shell wormhole (QSTSW) and investigate the stability of this wormhole. First we compute the surface stress at the wormhole throat by applying the Darmois-Israel formalism to the modified Schwarzschild metric and show that exotic matter is required at the throat to keep the wormhole stable. We then study the stability analysis of the wormhole by considering phantom-energy for the exotic matter, generalized Chaplygin gas (GCG), and the linearized stability analysis. It is argued that quantum corrections can affect the stability domain of the wormhole.
Quantum Corrected Schwarzschild Thin Shell Wormhole
Jusufi, Kimet
2016-01-01
Recently, Ali and Khalil \\cite{ahmed}, based on the Bohmian quantum mechanics derived a quantum corrected version of the Schwarzschild metric. In this paper, we construct a quantum corrected Schwarzschild thin shell wormhole (QSTSW) and investigate the stability of this wormhole. First we compute the surface stress at the wormhole throat by applying the Darmois-Israel formalism to the modified Schwarzschild metric and show that exotic matter is required at the throat to keep the wormhole stable. We then study the stability analysis of the wormhole by considering phantom-energy for the exotic matter, generalized Chaplygin gas (GCG), and the linearized stability analysis. It is argued that, quantum corrections can affect the stability domain of the wormhole.
Interior of a Schwarzschild black hole revisited
Doran, R; Lobo, F S N; Crawford, Paulo; Doran, Rosa; Lobo, Francisco S. N.
2006-01-01
The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the con...
Stahnisch, Frank W; Pow, Stephen
2015-01-01
The forced migration process of German-speaking neurologists and psychiatrists under the Nazis during the 1930s and 40s is often preoccupied solely with "successful" concepts and therapeutic approaches. The case of German-Canadian neurologist Karl Stern (1906-1975) is very instructive, however, since the process of forced migration, for him, proved to be a transitionary process from his former cutting edge work in neuropathology and holist neurology in Germany to clinical psychiatry and the development of the new discipline of geriatric medicine in Canada.
Quantum corrections to Schwarzschild black hole
Energy Technology Data Exchange (ETDEWEB)
Calmet, Xavier; El-Menoufi, Basem Kamal [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom)
2017-04-15
Using effective field theory techniques, we compute quantum corrections to spherically symmetric solutions of Einstein's gravity and focus in particular on the Schwarzschild black hole. Quantum modifications are covariantly encoded in a non-local effective action. We work to quadratic order in curvatures simultaneously taking local and non-local corrections into account. Looking for solutions perturbatively close to that of classical general relativity, we find that an eternal Schwarzschild black hole remains a solution and receives no quantum corrections up to this order in the curvature expansion. In contrast, the field of a massive star receives corrections which are fully determined by the effective field theory. (orig.)
Canonical energy and linear stability of Schwarzschild
Prabhu, Kartik; Wald, Robert
2017-01-01
Consider linearised perturbations of the Schwarzschild black hole in 4 dimensions. Using the linearised Newman-Penrose curvature component, which satisfies the Teukolsky equation, as a Hertz potential we generate a `new' metric perturbation satisfying the linearised Einstein equation. We show that the canonical energy, given by Hollands and Wald, of the `new' metric perturbation is the conserved Regge-Wheeler-like energy used by Dafermos, Holzegel and Rodnianski to prove linear stability and decay of perturbations of Schwarzschild. We comment on a generalisation of this strategy to prove the linear stability of the Kerr black hole.
Is the Schwarzschild black hole spurious?
Quirós, I
1999-01-01
A point of view is presented, according to which, the well known static, spherically symmetric Schwarzschild black hole of Einstein's general relativity for vacuum, can be interpreted as a virtual, devoid of invariant physical meaning, geometrical object due to a particular representation of the theory.
Optics in the Schwarzschild space-time
Cadez, A; Cadez, Andrej; Kostic, Uros
2004-01-01
Light coming from the strong gravity region in the vicinity of a black hole is marked by large Doppler shifts, redshifts and aberration effects. In order to understand these effects it is useful to solve the light propagation problem between any two given points in the curved space of a black hole. Here we describe the complete solution for the Schwarzschild space-time.
Karl Konrad Grass jumalainimeste uurijana / Alar Laats
Laats, Alar
2006-01-01
Karl Konrad Grass oli 19. sajandil Dorpati keiserliku ülikooli usuteaduskonna Uue Testamendi õppejõud, kes tegeles hobi korras idakristluse (vene sektid) uurimisega. Tema peateoseks on uurimus "Die russischen Sekten". Ettekanne konverentsil 15.-16. aprill 2005. a.
Karl Konrad Grass jumalainimeste uurijana / Alar Laats
Laats, Alar
2006-01-01
Karl Konrad Grass oli 19. sajandil Dorpati keiserliku ülikooli usuteaduskonna Uue Testamendi õppejõud, kes tegeles hobi korras idakristluse (vene sektid) uurimisega. Tema peateoseks on uurimus "Die russischen Sekten". Ettekanne konverentsil 15.-16. aprill 2005. a.
KARL MAYER Aims to Shape The Future
Institute of Scientific and Technical Information of China (English)
2012-01-01
Review of KARL MAYER at ITMA ASIA + CITME 2012 in Shanghai This June, during the ITMA ASIA + CITME 2012 exhibition that was held on June 12th-16th in the city of Shanghai, the exhibition stand of Karl Mayer without doubt spotlighted all the attention in the entire warp knitting sector, bringing its clever and innovative solutions to global visitors, particularly the customers in Asia.
Karl Kello - elukutse olla saarlane / Aare Laine
Laine, Aare, 1951-
2004-01-01
Kuressaare Kuursaalis näidati kadripäeval nelja Ruta Celma ja Karl Kello kultuuriloolist dokumentaalfilmi : "Narr Jumala kojas" (2000), "Phaetonit otsides" (1999), "Eestlased Lätis" (2004) ja Kalevipoja temaatikat arendav "Küll siis Kalev..." (2004). Filmide operaator on Arvo Vilu. Artikli autor kõneleb Karl Kellost, tema Karja kiriku ja Kaali järve problemaatika arendustest peale filmide ka kirjasõnas
Karl Kello - elukutse olla saarlane / Aare Laine
Laine, Aare, 1951-
2004-01-01
Kuressaare Kuursaalis näidati kadripäeval nelja Ruta Celma ja Karl Kello kultuuriloolist dokumentaalfilmi : "Narr Jumala kojas" (2000), "Phaetonit otsides" (1999), "Eestlased Lätis" (2004) ja Kalevipoja temaatikat arendav "Küll siis Kalev..." (2004). Filmide operaator on Arvo Vilu. Artikli autor kõneleb Karl Kellost, tema Karja kiriku ja Kaali järve problemaatika arendustest peale filmide ka kirjasõnas
Classroom reconstruction of the Schwarzschild metric
Kassner, Klaus
2015-01-01
A promising way to introduce general relativity in the classroom is to study the physical predictions that follow from certain given metrics, such as the Schwarzschild one. This involves lower mathematical expenditure than an approach focusing on differential geometry in its full glory and permits to emphasize physical aspects before attacking the field equations. Even so, in terms of motivation, lacking justification of the metric employed may pose an obstacle. The paper discusses how to establish the weak-field limit of the Schwarzschild metric with a minimum of relatively simple physical assumptions. Since this does not appear sufficient to arrive at a form of the metric useful for more than the most basic predictions (gravitational redshift), the determination of a single additional parameter from experiment is admitted. An attractive experimental candidate is the measurement of the perihelion precession of Mercury, because the result was already known before the completion of general relativity. It is sh...
Central charge for the Schwarzschild black hole
Ropotenko, K.
2016-12-01
Proceeding in exactly the same way as in the derivation of the temperature of a dual CFT for the extremal black hole in the Kerr/CFT correspondence, it is found that the temperature of a chiral, dual CFT for the Schwarzschild black hole is T = 1/2π. Comparing Cardy’s formula with the Bekenstein-Hawking entropy and using T, it is found that the central charge for the Schwarzschild black hole is of the form c = 12Jin, where Jin is the intrinsic angular momentum of the black hole, Jin = A/8πG. It is shown that the central charge for any four-dimensional (4D) extremal black hole is of the same form. The possible universality of this form is briefly discussed.
Gauge Invariant Perturbations of the Schwarzschild Spacetime
Chen, Hector; Whiting, Bernard F
2016-01-01
Beginning with the pioneering work of Regge and Wheeler (Phys. Rev. 108, 1957), there have been many studies of perturbations away from the Schwarzschild spacetime background. In particular several authors (e.g. Moncrief, Ann. Phys 88, 1974) have investigated gauge invariant quantities of the Regge-Wheeler (RW) gauge. Steven Detweiler also investigated perturbations of Schwarzschild in his own gauge, which he denoted the "easy (EZ) gauge", and which he was in the process of adapting for use in the second-order self-force problem. We present here a compilation of some of his working results, arising from notes for which there seems to have been no manuscript in preparation. In particular, we list the gauge invariant quantities used by Detweiler, as well as explain the process by which he found them.
The Planck Vacuum and the Schwarzschild Metrics
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2009-07-01
Full Text Available The Planck vacuum (PV is assumed to be the source of the visible universe. So under conditions of sufficient stress, there must exist a pathway through which energy from the PV can travel into this universe. Conversely, the passage of energy from the visible universe to the PV must also exist under the same stressful conditions. The following examines two versions of the Schwarzschild metric equation for compatability with this open-pathway idea.
Schwarzschild solution from Weyl transverse gravity
Oda, Ichiro
2017-01-01
We study classical solutions in the Weyl-transverse (WTDiff) gravity. The WTDiff gravity is invariant under both the local Weyl (conformal) transformation and the volume preserving diffeomorphisms (Diff) (transverse diffeomorphisms (TDiff)) and is known to be equivalent to general relativity at least at the classical level. In particular, we find that in a general spacetime dimension, the Schwarzschild metric is a classical solution in the WTDiff gravity when it is expressed in the Cartesian coordinate system.
Flowing liquid crystal simulating the Schwarzschild metric
Energy Technology Data Exchange (ETDEWEB)
Pereira, Erms R.; Moraes, Fernando [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)
2009-07-01
Full text. We show how to simulate the equatorial section of the Schwarzschild metric through a flowing liquid crystal in its nematic phase. Inside a liquid crystal in the nematic phase, a traveling light ray feels an effective metric, whose properties are linked to perpendicular and parallel refractive indexes, no e ne respectively, of the rod-like molecule of the liquid crystal. As these indexes depend on the scalar order parameter of the liquid crystal, the Beris-Edwards hydrodynamic theory is used to connect the order parameter with the velocity of a liquid crystal flow at each point. This way we calculate a radial velocity profile that simulates the equatorial section of the Schwarzschild metric in the nematic phase of the liquid crystal. This work will be presented in the following way. First, we show the effective metric that describes the light propagation around a (k = 1; c = 0) disclination defect of the nematic phase of a liquid crystalline sample and how this light propagation can be described by the order parameter q of the liquid crystalline material. Afterwards, we consider the liquid crystal flowing radially and we use the Beris-Edwards theory to analyze the dependence of the order parameter of the material with the flowing velocity module. In these two cases we consider the more general situation of three space dimensions. Finally, we employ the result from the second part in the first and we compare with the Schwarzschild metric written in isotropic coordinates. (author)
Propagation of light in Schwarzschild geometry
Khorasani, Sina
2010-02-01
In this paper, the equivalent medium of Schwarzschild metric is discussed. The corresponding ray-tracing equations are integrated for the equivalent medium of the Schwarzschild geometry, which describes the curved space around a spherically symmetric, irrotational, and uncharged blackhole. We make comparison to the well-known expression by Einstein. While Einstein's estimate is reasonably good for large closest distances of approach to the star, it disregards the optical anisotropy of space. Instead, Virbhadra's estimate which takes the effects of anisotropy of Schwarzschild metric is shown to be more consistent with numerical simulations. Hence, a true physical anisotropy in the velocity of light under gravitational field does exist. We argue that the existence of such an optical anisotropy could be revealed exactly in the same way that the optical interferometry is expected to detect gravitational waves. Therefore, if no optical anisotropy under gravitational fields could be observed, then the possibility of interferometric detection of gravitational waves is automatically ruled out, and vice versa.
Conformal properties of the extremal Schwarzschild de-Sitter spacetime
Gasperin, Edgar
2015-01-01
The conformal structure of the extremal Schwarzschild de-Sitter spacetime is analysed using the extended conformal Einstein field equations. Initial data for an asymptotic initial value problem for the extremal Schwarzschild de-Sitter spacetime is obtained. Using the insights gained from the analysis of the reference spacetime we consider nonlinear perturbations close to the extremal Schwarzschild de-Sitter spacetime. We show that small enough perturbations of initial data for the extremal Schwarzschild de-Sitter spacetime, away from the singularity, give rise to a solution to the Einstein field equations which exists to the future and has an asymptotic structure similar to that of the extremal Schwarzschild de-Sitter spacetime. Similarly, we obtain an existence and stability result for asymptotic initial data close to that of the extremal Schwarzschild de-Sitter spacetime in the non-singular region.
Dynamics in the Charged Time Conformal Schwarzschild Black Hole
Jawad, Abdul; Shahzad, M Umair; Abbas, G
2016-01-01
In this work, we present the new technique for discussing the dynamical motion of neutral as well as charged particles in the absence/presence of magnetic field around the time conformal Schwarzschild black hole. Initially, we find the numerical solutions of geodesics of Schwarzschild black hole and the time conformal Schwarzschild black hole. We observe that the Schwarzschild spacetime admits the time conformal factor $e^{\\epsilon f(t)}$, where $f(t)$ is an arbitrary function and $\\epsilon$ is very small which causes the perturbation in the spacetimes. This technique also re-scale the energy content of spacetime. We also investigate the thermal stability, horizons and energy conditions corresponding time conformal Schwarzschild spacetime. Also, we examine the dynamics of neutral and charged particle around time conformal Schwarzschild black hole. We investigate the circumstances under which the particle can escape from vicinity of black hole after collision with another particle. We analyze the effective pot...
Restudy of the stability problem of the Schwarzschild black hole
Institute of Scientific and Technical Information of China (English)
Tian Gui-Hua; Wang Shi-Kun; Zhao Zheng
2006-01-01
The stability of the Schwarzschild black hole is restudied in the Painlevé coordinates. Using the Painlevé time coordinate to define the initial time, we reconsider the odd perturbation and find that the Schwarzschild black hole in the Painlevé coordinates is unstable. The Painlevé metric in this paper corresponds to the white-hole-connected region of the Schwarzschild black hole (r ＞ 2m) and the odd perturbation may be regarded as the angular perturbation.Therefore, the white-hole-connected region of the Schwarzschild black hole is unstable with respect to the rotating perturbation.
Dust ball physics and the Schwarzschild metric
Kassner, Klaus
2017-08-01
A physics-first derivation of the Schwarzschild metric is given. Gravitation is described in terms of the effects of tidal forces (or of spacetime curvature) on the volume of a small ball of test particles (a dust ball), freely falling after all particles were at rest with respect to each other initially. Because this formulation avoids the use of tensors, neither advanced tensor calculus nor sophisticated differential geometry are needed in the calculation. The derivation is not lengthy and it has visual appeal, so it may be useful in teaching.
Schwarzschild black holes can wear scalar wigs.
Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-08-24
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.
Schwarzschild black holes can wear scalar wigs
Barranco, Juan; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-01-01
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultra-light scalar field dark matter around supermassive black holes and axion-like scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic, in the sense that fairly arbitrary initial data evolves, at late times, as a combination of those long-lived configurations.
Holonomy in the Schwarzschild-Droste Geometry
Rothman, T; Murugan, J; Rothman, Tony; Ellis, George F. R.; Murugan, Jeff
2001-01-01
Parallel transport of vectors in curved spacetimes generally results in a deficit angle between the directions of the initial and final vectors. We examine such holonomy in the Schwarzschild-Droste geometry and find a number of interesting features that are not widely known. For example, parallel transport around circular orbits results in a quantized band structure of holonomy invariance. We also examine radial holonomy and extend the analysis to spinors and to the Reissner-Nordstr\\"om metric, where we find qualitatively different behavior for the extremal ($Q = M$) case. Our calculations provide a toolbox that will hopefully be useful in the investigation of quantum mechanical problems involving parallel transport.
Eigentensors of the Lichnerowicz operator in Euclidean Schwarzschild metrics
Energy Technology Data Exchange (ETDEWEB)
Martinez-Morales, J.L. [Instituto de Matematicas, Universidad Nacional Autonoma de Mexico, A. P. 273, Admon. de correos 3, C. P. 62251 Cuernavaca, Morelos (Mexico)
2006-09-01
Properties of the eigentensors of the Lichnerowicz Laplacian for the Euclidean Schwarzschild metric are discussed together with possible applications to the linear stability of higher-dimensional instantons. The main statement of the article is that any eigentensor of the Lichnerowicz operator in a Euclidean (possibly higher-dimensional) Schwarzschild metric is essentially singular at infinity. (Abstract Copyright [2006], Wiley Periodicals, Inc.)
Schwarzschild black-holes are quantum complete
Hofmann, Stefan
2016-01-01
The singularity theorem by Hawking and Penrose qualifies Schwarzschild black-holes as geodesic incomplete space-times. Albeit this is a mathematically rigorous statement, it requires an operational framework that allows to probe the space-like singularity via a measurement process. Any such framework necessarily has to be based on quantum theory. As a consequence, the notion of classical completeness needs to be adapted to situations where the only adequate description is in terms of quantum fields in dynamical space-times. It is shown that Schwarzschild black-holes turn out to be complete when probed by self-interacting quantum fields in the ground state and in excited states. The measure for populating quantum fields on hypersurfaces in the vicinity of the black-hole singularity goes to zero towards the singularity. This statement is robust under non-Gaussian deformations of and excitations relative to the ground state. The clash of completeness cultures as exemplified with black holes is discussed.
Gauge-invariant perturbations of Schwarzschild spacetime
Shah, Abhay G; Aksteiner, Steffen; Andersson, Lars; Bäckdahl, Thomas
2016-01-01
We study perturbations of Schwarzschild spacetime in a coordinate-free, covariant form. The GHP formulation, having the advantage of not only being covariant but also tetrad-rotation invariant, is used to write down the previously known odd- and even-parity gauge-invariants and the equations they satisfy. Additionally, in the even-parity sector, a new invariant and the second order hyperbolic equation it satisfies are presented. Chandrasekhar's work on transformations of solutions for perturbation equations on Schwarzschild spacetime is translated into the GHP form, i.e., solutions for the equations of the even- and odd-parity invariants are written in terms of one another, and the extreme Weyl scalars; and solutions for the equations of these latter invariants are also written in terms of one another. Recently, further gauge invariants previously used by Steven Detweiler have been described. His method is translated into GHP form and his basic invariants are presented here. We also show how these invariants ...
Gauge invariant perturbations of the Schwarzschild spacetime
Thompson, Jonathan E.; Chen, Hector; Whiting, Bernard F.
2017-09-01
Beginning with the pioneering work of Regge and Wheeler (1957 Phys. Rev. 108 1063), there have been many studies of perturbations away from the Schwarzschild spacetime background. In particular several authors Moncrief (1974 Ann. Phys. 88 323), Sachs (1964 Relativity, Groups and Topology (New York: Gordon and Breach)) and Brizuela et al (2007 Phys. Rev. D 76 024004) have investigated gauge invariant quantities of the Regge-Wheeler (RW) formalism. Steven Detweiler also investigated perturbations of Schwarzschild in his own formalism, introducing his own gauge choice which he denoted the ‘easy (EZ) gauge’, and which he was in the process of adapting for use in the second-order self-force problem. We present here a compilation of some of his working results, arising from notes for which there seems to have been no manuscript in preparation. In particular, we outline Detweiler’s formalism, list the gauge invariant quantities he used, and explain the process by which he found them.
Seitse võistlusromaani / Karl Ristikivi
Ristikivi, Karl, 1912-1977
1996-01-01
Kask, Agu. Unustatud sugpõlv; Rajamaa, Helmi. Varjutatud südamed; Thoen, Aino. Võlaraamat; Veskimäe, Viktor. Kolmas võimalus; Timmukuru, Juhan. Esimesed read; Einer, Karl. Ainult üks valge liblikas; Timmukuru, Juhan. Peep Koordipoja põlistalu
[Karl Landsteiner discovers the blood groups].
Lefrère, J-J; Berche, P
2010-02-01
The discovery of ABO blood group was a major step in mastering transfusion therapy. Karl Landsteiner (1868-1843) was the author of this discovery. This paper retraces the hard career of this American scientist of Austrian origin, and describes the circumstances that led his research to the discoveries, which were turning points in the history of the immunology.
Approximating light rays in the Schwarzschild field
Semerak, Oldrich
2014-01-01
A short formula is suggested which approximates photon trajectories in the Schwarzschild field better than other simple prescriptions from the literature. We compare it with various "low-order competitors", namely with those following from exact formulas for small $M$, with one of the results based on pseudo-Newtonian potentials, with a suitably adjusted hyperbola, and with the effective and often employed approximation by Beloborodov. Our main concern is the shape of the photon trajectories at finite radii, yet asymptotic behaviour is also discussed, important for lensing. An example is attached indicating that the newly suggested approximation is usable--and very accurate--for practical solving of the ray-deflection exercise.
Dust ball physics and the Schwarzschild metric
Kassner, Klaus
2016-01-01
A physics-first derivation of the Schwarzschild metric is given. Gravitation is described in terms of the effects of tidal forces (or of spacetime curvature) on the volume of a small ball of test particles (a dust ball), freely falling after all particles were at rest with respect to each other initially. The possibility to express Einstein's equation this way and some of its ramifications have been enjoyably discussed by Baez and Bunn [Am. J. Phys. 73, 644 (2005)]. Since the formulation avoids the use of tensors, neither advanced tensor calculus nor sophisticated differential geometry are needed in the calculation. The derivation is not lengthy and it has visual appeal, so it may be useful in teaching.
Microscopic corrections to the Schwarzschild spacetime
Culetu, Hristu
2015-01-01
A version of the Schwarzschild metric to be valid in microphysics is proposed. The source fluid is anisotropic with $p_{r} = -\\rho$ and fluctuating tangential pressures. At large distances with respect to the Compton wavelength associated to the source particle, they do not depend on the mass $m$ of the source and everywhere depend on $\\hbar$ and the velocity of light $c$ but not on the Newton constant $G$. The particle may be a black hole for $m \\geq m_{P}$ only and when $m = m_{P}$ it becomes an extremal black hole. The Komar energy $W$ of the gravitational fluid is $mc^{2}$ for $\\hbar = 0$ and at large distances and vanishes at $r_{0} = 2\\hbar/emc$. The WEC is violated when $r < r_{0}/2$ due to the negative tangential pressures. The horizon entropy for the extremal black hole is finite though $W$ and the temperature $T$ are vanishing there.
A Schwarzschild-like model for baryons
Singleton, D.; Yoshida, A.
2002-06-01
We present a toy model of baryons using singular solutions of the SU(2) Yang-Mill-Higgs (YMH) field equations, which bears some similarity to the Schwarzschild solution of general relativity. The SU (2) solutions are used as a background field into which a scalar, SU (2) test particle is placed. This can be compared to placing an electrically charged particle in a Coulomb background field, except the SU (2) YMH solutions are singular on a spherical membrane thus trapping (confining) the test particle inside the sphere in a manner similar to certain bag models of baryons. An interesting consequence of this model is that the composite system is a fermion even though the original Lagrangian contains only bosonic fields.
Loop quantization of the Schwarzschild interior revisited
Corichi, Alejandro
2015-01-01
The loop quantization of the Schwarzschild interior region, as described by a homogenous anisotropic Kantowski-Sachs model, is re-examined. As several studies of different --inequivalent-- loop quantizations have shown, to date there exists no fully satisfactory quantum theory for this model. This fact posses challenges to the validity of some scenarios to address the black hole information problem. Here we put forward a novel viewpoint to construct the quantum theory that builds from some of the models available in the literature. The final picture is a quantum theory that is both independent of any auxiliary structure and possesses a correct low curvature limit. It represents a subtle but non-trivial modification of the original prescription given by Ashtekar and Bojowald. It is shown that the quantum gravitational constraint is well defined past the singularity and that its effective dynamics possesses a bounce into an expanding regime. The classical singularity is avoided, and a semiclassical spacetime sa...
Landau problem in the static schwarzschild universe
Directory of Open Access Journals (Sweden)
A Jafari
2013-09-01
Full Text Available This paper considers the Landau problem in an elected static space time and the are erased levels shifts which are erased as a metric deviation from the Minkowski space time. This research is based on the Weber’s method. We try to rewrite the equation of motion of particles in the presence of the gravitational effects and consider the regions limited with the tangent spaces conditions. I t would be reasonable to assume the nonrelativistic particles with low speed. We show that due to the Weber’s method, the tangent space is always available. Another assumption of this article is time independent tangent space of Schwarzschild universe and use of Riemann’s normal coordinates.
Electromagnetic waves in a strong Schwarzschild plasma
Energy Technology Data Exchange (ETDEWEB)
Daniel, J.; Tajima, T.
1996-11-01
The physics of high frequency electromagnetic waves in a general relativistic plasma with the Schwarzschild metric is studied. Based on the 3 + 1 formalism, we conformalize Maxwell`s equations. The derived dispersion relations for waves in the plasma contain the lapse function in the plasma parameters such as in the plasma frequency and cyclotron frequency, but otherwise look {open_quotes}flat.{close_quotes} Because of this property this formulation is ideal for nonlinear self-consistent particle (PIC) simulation. Some of the physical consequences arising from the general relativistic lapse function as well as from the effects specific to the plasma background distribution (such as density and magnetic field) give rise to nonuniform wave equations and their associated phenomena, such as wave resonance, cutoff, and mode-conversion. These phenomena are expected to characterize the spectroscopy of radiation emitted by the plasma around the black hole. PIC simulation results of electron-positron plasma are also presented.
Relativistic gas in a Schwarzschild metric
Kremer, Gilberto M
2013-01-01
A relativistic gas in a Schwarzschild metric is studied within the framework of a relativistic Boltzmann equation in the presence of gravitational fields, where Marle's model for the collision operator of the Boltzmann equation is employed. The transport coefficients of bulk and shear viscosities and thermal conductivity are determined from the Chapman-Enskog method. It is shown that the transport coefficients depend on the gravitational potential. Expressions for the transport coefficients in the presence of weak gravitational fields in the non-relativistic (low temperatures) and ultra-relativistic (high temperatures) limiting cases are given. Apart from the temperature gradient the heat flux has two relativistic terms. The first one, proposed by Eckart, is due to the inertia of energy and represents an isothermal heat flux when matter is accelerated. The other, suggested by Tolman, is proportional to the gravitational potential gradient and indicates that -- in the absence of an acceleration field -- a stat...
The dynamical model and quantization of the Schwarzschild black hole
Institute of Scientific and Technical Information of China (English)
2008-01-01
The mass of the Schwarzschild black hole, an observable quantity, is defined as a dynamical variable, while the corresponding conjugate is considered as a general- ized momentum. Then a two-dimensional phase space is composed of the two variables. In the two-dimensional phase space, a harmonic oscillator model of the Schwarzschild black hole is obtained by a canonical transformation. By this model, the mass spectrum of the Schwarzschild black hole is firstly obtained. Further the horizon area operator, quantum area spectrum and entropy are obtained in the Fock representation. Lastly, the wave function of the horizon area is derived also.
Offshell thermodynamic metrics of the Schwarzschild black hole
Wen, Wen-Yu
2016-01-01
Thermodynamic metric usually works only for those black holes with more than one conserved charge, therefore the Schwarzschild black hole was excluded. In this letter, we compute and compare different versions of offshell thermodynamic metric for the Schwarzschild-like black hole by introducing a new degree of freedom. This new degree of freedom could be the running Newton constant, a cutoff scale for regular black hole, a noncommutative deformation, or the deformed parameter in the nonextensive Tsallis-Renyi entropy. The onshell metric of the deformed Schwarzschild solution would correspond to the submanifold by gauge fixing of this additional degree of freedom. In particular, the thermal Ricci scalar for the Schwarzschild black hole, though different for various deformation, could be obtained by switching off the deformation.
Thermodynamics of Schwarzschild-Beltrami-de Sitter Black Hole
Liu, Hang
2016-01-01
In this paper, we investigate the thermodynamical properties of Schwarzschild-Beltrami-de Sitter black hole introduced by Mu-Lin Yan \\textit{et al.} in 2013 by introducing inertial Beltrami coordinates to traditional non-inertial Schwarzschild-de Sitter metric which is the exact static spherical symmetry solution of Einstein equation with a positive cosmological constant $\\Lambda$. Based on this new metric, we compute entropy on all horizons and we give the entropy bound of the black hole. Hawking temperatures are calculated by considering a perturbation to entropy relations due to that there does not exist a killing horizon where the surface gravity related to Hawking temperature is defined well in this inertial coordinates. We also get the Smarr relations and the first law of thermodynamics. We find that the Schwarzschild-Beltrami-de Sitter black hole has almost the same thermodynamical properties as Schwarzschild-de Sitter black hole in the comparison between their corresponding thermodynamical quantities,...
Karl Popper and Evolutionary Concept of Epistemology
Ebrahim Ashni Alvandi; Majid Akbari Dehagi
2008-01-01
Epistemology and its formational trend have been always one of the discussions in various parts of science; and nowadays modern sciences have plentiful effects on the process of epistemological studies. Different men of letters from various fields have also studied and scrutinized it. Among these researches, evolutionary epistemology wants to explain the process of formation of epistemology by modeling it through evolution theory. Here I do effort to investigate Karl Poppers’ view point of ep...
Effects of Schwarzschild Geometry on Isothermal Plasma Wave Dispersion
Sharif, M.; Sheikh, Umber
2007-01-01
The behavior of isothermal plasma waves has been analyzed near the Schwarzschild horizon. We consider a non-rotating background with non-magnetized and magnetized plasmas. The general relativistic magnetohydrodynamical equations for the Schwarzschild planar analogue spacetime with an isothermal state of the plasma are formulated. The perturbed form of these equations is linearized and Fourier analyzed by introducing simple harmonic waves. The determinant of these equations in each case leads ...
Dynamics of particles around time conformal Schwarzschild black hole
Energy Technology Data Exchange (ETDEWEB)
Jawad, Abdul; Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Ali, Farhad [Kohat University of Science and Technology, Department of Mathematics, Kohat (Pakistan); Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)
2016-11-15
In this work, we present the new technique for discussing the dynamical motion of neutral as well as charged particles in the absence/presence of a magnetic field around the time conformal Schwarzschild black hole. Initially, we find the numerical solutions of geodesics of the Schwarzschild black hole and the time conformal Schwarzschild black hole. We observe that the Schwarzschild spacetime admits the time conformal factor e{sup εf(t)}, where f(t) is an arbitrary function and ε is very small, which causes a perturbation in the spacetimes. This technique also re-scales the energy content of spacetime. We also investigate the thermal stability, horizons and energy conditions corresponding to time conformal Schwarzschild spacetime. Also, we examine the dynamics of a neutral and charged particle around a time conformal Schwarzschild black hole. We investigate the circumstances under which the particle can escape from the vicinity of a black hole after collision with another particle. We analyze the effective potential and effective force of a particle in the presence of a magnetic field with angular momentum graphically. (orig.)
Note on the Schwarzschild-phantom wormhole
Lukmanova, Regina; Izmailov, Ramil; Yanbekov, Almir; Karimov, Ramis; Potapov, Alexander A
2016-01-01
Recently, it has been shown by Lobo, Parsaei and Riazi (LPR) that phantom energy with $\\omega =p_{r}/\\rho <-1$ could support phantom wormholes. Several classes of such solutions have been derived by them. While the inner spacetime is represented by asymptotically flat phantom wormhole that have repulsive gravity, it is most likely to be unstable to perturbations. Hence, we consider a situation, where a phantom wormhole is somehow trapped inside a Schwarzschild sphere across a thin shell. Applying the method developed by Garcia, Lobo and Visser (GLV), we shall exemplify that the shell can possess zones of stability depending on certain constraints. It turns out that zones corresponding to "force" constraint are more restrictive than those from the "mass" constraint. We shall also enumerate the interior energy content by using the gravitational energy integral proposed by Lynden-Bell, Katz and Bi% \\v{c}\\'ak. It turns out that, even though the interior mass is positive, the integral implies repulsive energy. ...
Caustic echoes from a Schwarzschild black hole
Zenginoğlu, Anıl
2012-01-01
We present the first numerical construction of the scalar Schwarzschild Green function in the time-domain, which reveals several universal features of wave propagation in black hole spacetimes. We demonstrate the trapping of energy near the photon sphere and confirm its exponential decay. The trapped wavefront propagates through caustics resulting in echoes that propagate to infinity. The arrival times and the decay rate of these caustic echoes are consistent with propagation along null geodesics and the large l-limit of quasinormal modes. We show that the four-fold singularity structure of the retarded Green function is due to the well-known action of a Hilbert transform on the trapped wavefront at caustics. A two-fold cycle is obtained for degenerate source-observer configurations along the caustic line, where the energy amplification increases with an inverse power of the scale of the source. Finally, we discuss the tail piece of the solution due to propagation within the light cone, up to and including nu...
Hawking radiation inside a Schwarzschild black hole
Hamilton, Andrew J S
2016-01-01
The boundary of any observer's spacetime is the boundary that divides what the observer can see from what they cannot see. The boundary of an observer's spacetime in the presence of a black hole is not the true (future event) horizon of the black hole, but rather the illusory horizon, the dimming, redshifting surface of the star that collapsed to the black hole long ago. The illusory horizon is the source of Hawking radiation seen by observers both outside and inside the true horizon. The perceived acceleration (gravity) on the illusory horizon sets the characteristic frequency scale of Hawking radiation, even if that acceleration varies dynamically, as it must do from the perspective of an infalling observer. The acceleration seen by a non-rotating free-faller both on the illusory horizon below and in the sky above is calculated for a Schwarzschild black hole. Remarkably, as an infaller approaches the singularity, the acceleration becomes isotropic, and diverging as a power law. The isotropic, power-law char...
Journey Beyond the Schwarzschild Black Hole Singularity
Araya, Ignacio J; James, Albin
2015-01-01
We present the geodesical completion of the Schwarzschild black hole in four dimensions which covers the entire space in (u,v) Kruskal-Szekeres coordinates, including the spacetime behind the black and white hole singularities. The gravitational constant switches sign abruptly at the singularity, thus we interpret the other side of the singularity as a region of antigravity. The presence of such sign flips is a prediction of local (Weyl) scale invariant geodesically complete spacetimes which improve classical general relativity and string theory. We compute the geodesics for our new black hole and show that all geodesics of a test particle are complete. Hence, an ideal observer, that starts its journey in the usual space of gravity, can reach the other side of the singularity in a finite amount of proper time. As usual, an observer outside of the horizon cannot verify that such phenomena exist. However, the fact that there exist proper observers that can see this, is of fundamental significance for the constr...
Inside the Schwarzschild-Tangherlini black holes
Matyjasek, Jerzy
2015-01-01
The first-order semiclassical Einstein field equations are solved in the interior of the Schwarzschild-Tangherlini black holes. The source term is taken to be the stress-energy tensor of the quantized massive scalar field with arbitrary curvature coupling calculated within the framework of the Schwinger-DeWitt approximation. It is shown that for the minimal coupling the quantum effects tend to isotropize the interior of the black hole (which can be interpreted as an anisotropic collapsing universe) for D=4 and 5, whereas for D=6 and 7 the spacetime becomes more anisotropic. Similar behavior is observed for the conformal coupling with the reservation that for D=5 isotropization of the spacetime occurs during (approximately) the first 1/3 of the lifetime of the interior universe. On the other hand, we find that regardless of the dimension, the quantum perturbations initially strengthen the grow of curvature and its later behavior depends on the dimension and the coupling. It is shown that the Karlhede's scalar ...
Harmonic gauge perturbations of the Schwarzschild metric
Berndtson, Mark V
1996-01-01
The satellite observatory LISA will be capable of detecting gravitational waves from extreme mass ratio inspirals (EMRIs), such as a small black hole orbiting a supermassive black hole. The gravitational effects of the much smaller mass can be treated as the perturbation of a known background metric, here the Schwarzschild metric. The perturbed Einstein field equations form a system of ten coupled partial differential equations. We solve the equations in the harmonic gauge, also called the Lorentz gauge or Lorenz gauge. Using separation of variables and Fourier transforms, we write the frequency domain solutions in terms of six radial functions which satisfy decoupled ordinary differential equations. The six functions are the Zerilli and five generalized Regge-Wheeler functions of spin 2,1,0. We use the solutions to calculate the gravitational self-force for circular orbits. The self-force gives the first order perturbative corrections to the equations of motion. Section 1.2 of the thesis has a more detailed ...
"Unmapped Territories": The Career of Karl Kroeber (1926-2009)
Ruoff, A. Lavonne Brown
2012-01-01
Jean Taylor Kroeber, widow of Karl Kroeber, has granted permission for "SAIL" to reprint his "Address to Columbia College Students Elected to the Phi Beta Kappa Society, 18 May 2009" and "An Interview with Karl Kroeber." Conducted by Michael Mallick, the interview was published in the newsletter of the Department of English and Comparative…
Profiles in Research: An Interview with Karl Gustav Joreskog
Wainer, Howard
2011-01-01
This article presents an interview with Karl Gustav Joreskog. Karl Gustav Joreskog was born in Amal, Sweden, on April 25, 1935. He did his undergraduate studies at Uppsala University from 1955 to 1957, with a major in mathematics and physics. He received a PhD in statistics at Uppsala University in 1963, and he was a research statistician at…
Quantum Mechanical Corrections to the Schwarzschild Black Hole Metric
Bargueño, P; Nowakowski, M; Batic, D
2016-01-01
Motivated by quantum mechanical corrections to the Newtonian potential, which can be translated into an $\\hbar$-correction to the $g_{00}$ component of the Schwarzschild metric, we construct a quantum mechanically corrected metric assuming $-g_{00}=g^{rr}$. We show how the Bekenstein black hole entropy $S$ receives its logarithmic contribution provided the quantum mechanical corrections to the metric are negative. In this case the standard horizon at the Schwarzschild radius $r_S$ increases by small terms proportional to $\\hbar$ and a remnant of the order of Planck mass emerges. We contrast these results with a positive correction to the metric which, apart from a corrected Schwarzschild horizon, leads to a new purely quantum mechanical horizon. In such a case the quantum mechanical corrections to the entropy are logarithmic and polynomial.
How to obtain the Schwarzschild metric before Einstein's field equations
Kassner, Klaus
2016-01-01
As is well-known, there is no way to derive the Schwarzschild metric on the basis of pre-general-relativistic physics alone, which means using only special relativity, the Einstein equivalence principle and the Newtonian limit. It is however possible to encode the additional physics needed in two reasonably plausible postulates allowing to deduce the exact Schwarzschild metric without invoking Einstein's field equations. Since these requirements are designed to apply to the spherically symmmetric case, their union is much less powerful than the postulates from which Einstein obtained his field equations. It is shown that the field equations imply the postulates given here but that the converse is not quite true. The approach provides a fairly fast calculation method for the Schwarzschild metric in arbitrary coordinates exhibiting stationarity.
A Perspicuous Description of the Schwarzschild Black Hole Geodesics
Arik, Metin
2016-01-01
Schwarzschild black hole is the simplest black hole that is studied most in detail. Its behavior is best understood by looking at the geodesics of the particles under the influence of its gravitational field. In this paper, the focus of attention is giving a perspicuous description of the Schwarzschild geodesics by using analogue potential approach. Specifically we discuss geodesics of light and of a massive particle in the case that their angular momentum is non zero in the Schwarzschild spacetime. This discussion is done by defining analogue potentials out of geodesic equations and defining relevant dimensionless conserved quantities. Then, we designate how geodesics change in response to the change of these quantities. Our results indicate the relation between the particles' motion near black hole horizon and their angular momentum. Furthermore, we make a comparison between Newtonian Physics (NP) and General Relativity (GR) in the language of the analogue potential approach.
Cardy-Verlinde Formula of Noncommutative Schwarzschild Black Hole
Directory of Open Access Journals (Sweden)
G. Abbas
2014-01-01
Full Text Available Few years ago, Setare (2006 has investigated the Cardy-Verlinde formula of noncommutative black hole obtained by noncommutativity of coordinates. In this paper, we apply the same procedure to a noncommutative black hole obtained by the coordinate coherent approach. The Cardy-Verlinde formula is entropy formula of conformal field theory in an arbitrary dimension. It relates the entropy of conformal field theory to its total energy and Casimir energy. In this paper, we have calculated the total energy and Casimir energy of noncommutative Schwarzschild black hole and have shown that entropy of noncommutative Schwarzschild black hole horizon can be expressed in terms of Cardy-Verlinde formula.
Effects of Schwarzschild Geometry on Isothermal Plasma Wave Dispersion
Sharif, M
2007-01-01
The behavior of isothermal plasma waves has been analyzed near the Schwarzschild horizon. We consider a non-rotating background with non-magnetized and magnetized plasmas. The general relativistic magnetohydrodynamical equations for the Schwarzschild planar analogue spacetime with an isothermal state of the plasma are formulated. The perturbed form of these equations is linearized and Fourier analyzed by introducing simple harmonic waves. The determinant of these equations in each case leads to a complex dispersion relation, which gives complex values of the wave number. This has been used to discuss the nature of the waves and their characteristics near the horizon.
Interior properties of five-dimensional Schwarzschild black hole
Hong, Soon-Tae
2014-01-01
We investigate inner structure of Schwarzschild black hole on a five-dimensional spacetime S^3xR^2. To do this, we exploit a f\\"unfbein scheme. In particular, we construct an equation of state of hydrostatic equilibrium for the five-dimensional Schwarzschild black hole, which is a five-dimensional version of the Tolman-Oppenheimer-Volkoff equation on four-dimensional manifold. We also investigate uniform density interior configuration of the five-dimensional black hole which consists of incompressible fluid of density, to find a general relativistic expression for pressure.
Finite entropy of Schwarzschild anti-de Sitter black hole in different coordinates
Institute of Scientific and Technical Information of China (English)
Ding Chi-Kun; Jing Ji-Liang
2007-01-01
This paper studies the finite statistical-mechanical entropy of the Schwarzschild anti-de Sitter (AdS) spacetime At first glance, it seems that the results would be different from that in the Schwarzschild-like coordinate since both the entropies in these coordinates are exactly equivalent to that in the Schwarzschild-like coordinate.
Karl Kautsky e as origens do Cristianismo
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Luiz Alberto Moniz Bandeira
2010-08-01
Full Text Available Prólogo à obra “A Origem do Cristianismo”, de Karl Kautsky (Rio de Janeiro: Civilização Brasileira, 2010, p. 07-19
Kernaspekte van die kennissosiologie van Karl Mannheim
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A. D. Louw
1985-03-01
Full Text Available The author deals with certain crucial aspects of the sociology of knowledge of Karl Mannheim in view of the fact that he finds that the increase, worldwide, of interest in ideological difficulties in South Africa can fruitfully be dealt with in terms of this form of sociology. This is justified in part by Mannheim's viewpoint that thought is a function of human existence, and this function emanates from needs based on social factors. He traces Mannheim's use of the term ideology (in Sociology, culminating With the Idea that “the birth and death of ideology depends on certain social, economic and 'ecological' factors”. Subsequently he deals with a whole line of aspects of the sociology of knowledge as expounded by Mannheim, culminating in the idea that shifts in views with regard to lifeview and underlying values take place when there is a rapid upward (vertical mobility, leading to uncertainties and a lack of trust in established values.
Karl Korsch e a Comuna de Paris
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Luciano Cavini Martorano
2011-03-01
Full Text Available
Apesar de haver escrito uma extensa obra que ainda vem sendo editada no seu país natal, o marxista alemão Karl Korsch é praticamente desconhecido no Brasil – exceção feita a alguns poucos pesquisadores. Além da recente edição brasileira de seu importante trabalho Marxismo e filosofia (Editora UFRJ, e de alguns outros textos e artigos que podem ser encontrados em diferentes sites, o acesso ao conjunto de sua obra ainda é bastante difícil.
Divining and knowing: Karl Sudhoff's historical method.
Stein, Claudia
2013-01-01
This article investigates the historical method of Karl Sudhoff (1853- 1938), Germany's first professor of medical history. It argues that in order to understand his ideas more fully, we need to step outside the historiography of medical history and assess his methodology in relation to the norms and ideals of German academic history writing in general. The article demonstrates that the philology-based "critical method" of Leopold von Ranke (1795-1886) was central to Sudhoff's methodological thinking. It investigates the underlying philosophical and epistemological assumptions of Ranke's method, which tend to be less appreciated than his overt empiricism and explores how Sudhoff applied these to the new professionalizing subdiscipline of the history of medicine. The article argues that Sudhoff's concerns with the methodology of history, which involved a particular conception of the relationship between the human sciences and the medical sciences, offers compelling addresses to our times.
Moving Schwarzschild Black Hole and Modified Dispersion Relations
Hinojosa, Cristian Barrera
2015-01-01
We study the thermodynamics of a moving Schwarzschild black hole, identifying the temperature and entropy in a relativistic scenario. Furthermore, we set arguments in a framework relating invariant geometrical quantities under global spacetime transformations and the dispersion relation of the system. We then extended these arguments in order to consider more general dispersion relations, and identify criteria to rule them out.
Moving Schwarzschild black hole and modified dispersion relations
Directory of Open Access Journals (Sweden)
Cristian Barrera Hinojosa
2015-10-01
Full Text Available We study the thermodynamics of a moving Schwarzschild black hole, identifying the temperature and entropy in a relativistic scenario. Furthermore, we set arguments in a framework relating invariant geometrical quantities under global spacetime transformations and the dispersion relation of the system. We then extended these arguments in order to consider more general dispersion relations, and identify criteria to rule them out.
Spacelike spherically symmetric CMC foliation in the extended Schwarzschild spacetime
Lee, Kuo-Wei
2015-01-01
We first summarize the characterization of smooth spacelike spherically symmetric constant mean curvature (SS-CMC) hypersurfaces in the Schwarzschild spacetime and Kruskal extension. Then use the characterization to prove special SS-CMC foliation property, and verify part of the conjecture by Malec and \\'{O} Murchadha in their 2003 paper.
Phantom Accretion onto the Schwarzschild de-Sitter Black Hole
Institute of Scientific and Technical Information of China (English)
M Sharif; G Abbas
2011-01-01
We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flux conservation, relativistic Bernoulli equation and mass Bux conservation equation are formulated to discuss the phantom accretion. We discuss the conditions for critical accretion. It is found that the mass of the black hole decreases due to phantom accretion. There exist two critical points which lie in the exterior of horizons (black hole and cosmological horizons). The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking A → 0.%@@ We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole.The energy flux conserva-tion,relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom accretion.We discuss the conditions for critical accretion.It is found that the mass of the black hole decreases due to phantom accretion.There exist two critical points which lie in the exterior of horizons(black hole and cosmological horizons).The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking ∧→0.
The golden ratio in Schwarzschild-Kottler black holes
Energy Technology Data Exchange (ETDEWEB)
Cruz, Norman [Universidad de Santiago de Chile, Departamento de Fisica, Facultad de Ciencia, Santiago 2 (Chile); Olivares, Marco [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Villanueva, J.R. [Universidad de Valparaiso, Instituto de Fisica y Astronomia, Valparaiso (Chile)
2017-02-15
In this paper we show that the golden ratio is present in the Schwarzschild-Kottler metric. For null geodesics with maximal radial acceleration, the turning points of the orbits are in the golden ratio Φ = (√(5)-1)/2. This is a general result which is independent of the value and sign of the cosmological constant Λ. (orig.)
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.
Schwarzschild models of the Sculptor dSph galaxy
Breddels, M. A.; Helmi, A.; van den Bosch, R. C. E.; van de Ven, G.; Battaglia, G.
2012-01-01
We have developed a spherically symmetric dynamical model of a dwarf spheroidal galaxy using the Schwarzschild method. This type of modelling yields constraints both on the total mass distribution (e.g. enclosed mass and scale radius) as well as on the orbital structure of the system modelled (e.g.
Construction and enlargement of traversable wormholes from Schwarzschild black holes
Koyama, H; Koyama, Hiroko; Hayward, Sean A.
2004-01-01
Analytic solutions are presented which describe the construction of a traversable wormhole from a Schwarzschild black hole, and the enlargement of such a wormhole, in Einstein gravity. The matter model is pure radiation which may have negative energy density (phantom or ghost radiation) and the idealization of impulsive radiation (infinitesimally thin null shells) is employed.
Embeddings and time evolution of the Schwarzschild wormhole
Collas, Peter
2011-01-01
We show how to embed spacelike slices of the Schwarzschild wormhole (or Einstein-Rosen bridge) in R^3. Graphical images of embeddings are given, including depictions of the dynamics of this non-traversable wormhole at constant Kruskal times up to, and beyond, the "pinching off" at Kruskal times \\pm1.
Electromagnetic and gravitational fields in a Schwarzschild space-time
Energy Technology Data Exchange (ETDEWEB)
Porrill, J.; Stewart, J.M. (Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics)
1981-05-19
The propagation of electromagnetic fields and linearized perturbations of the vacuum Einstein equations on a Schwarzchild background space-time are discussed, and relations between the asymptotic form of the fields at null infinity and the data are established. Without suitable restrictions on the data, perturbations of a Schwarzschild space-time need not be weakly asymptotically simple.
A Complete Foliation of Schwarzschild Spacetime by Free Falling Hypersurfaces
Institute of Scientific and Technical Information of China (English)
M. Ayub Faridi; Amjad Pervez; Haris Rashid; Fazal-e-Aleem
2006-01-01
Free falling hypersurfaces in the Schwarzschild geometry have been studied to provide a complete foliation of spacetime. The hypersurfaces do not cross into the maximally extended spacetime and are well behaved everywhere except at the singularity r = 0 the mean extrinsic curvature becomes infinity.
Scalar wave scattering from Schwarzschild black holes in modified gravity
Sibandze, Dan B; Maharaj, Sunil D; Nzioki, Anne Marie; Dunsby, Peter K S
2016-01-01
We consider the scattering of gravitational waves off a Schwarzschild Black Hole in $f(R)$ gravity. We find that, while the reflection and transmission coefficients for tensor waves are the same as in General Relativity, a larger fraction of scalar waves are reflected compared to what one obtains for tensors. This may provide a novel observational signature for fourth order gravity.
Stability of relativistic Bondi accretion in Schwarzschild-(anti-)de Sitter spacetimes
Mach, Patryk
2013-01-01
In a recent paper we investigated stationary, relativistic Bondi-type accretion in Schwarzschild-(anti-)de Sitter spacetimes. Here we study their stability, using the method developed by Moncrief. The analysis applies to perturbations satisfying the potential flow condition. We prove that global isothermal flows in Schwarzschild-anti-de Sitter spacetimes are stable, assuming the test-fluid approximation. Isothermal flows in Schwarzschild-de Sitter geometries and polytropic flows in Schwarzschild-de Sitter and Schwarzschild-anti-de Sitter spacetimes can be stable, under suitable boundary conditions.
Astronomy from Olbers to Schwarzschild. (German Title: Astronomie von Olbers bis Schwarzschild)
Dick, Wolfgang R.; Hamel, Jürgen
This issue comprises talks presented 2000 September 18 at the colloquium ``International relations in astronomy'' it is supplemented by additional articles about this topic. The foundation of the international ``Vereinigte Astronomische Gesellschaft'', which took place in 1800 in Bremen, prompted us to investigate the development of astronomy in German-speaking regions, and its international relations during the 19th century. We investigate the activities of famous astronomers like W. Olbers, J.E. Bode, F.X. von Zach, J.H. Schroeter, H.C. Schumacher and K. Schwarzschild, as well as those of their less famous professional colleagues like J.G. Schrader and L. de Ball. The geographical spectrum extends from Bremen and Lilienthal over Kiel, Gotha and Dresden to Copenhagen, Vienna and Chile. Among the topics are: telescope construction, including telescopes made by Herschel, the rediscovery of the minor planet Ceres 1801/02, the Berlin ``Astronomisches Jahrbuch'', the foundation of the ``Astronomische Nachrichten'', the evolution from the ``Vereinigte Astronomische Gesellschaft'' to the present-day ``Astronomische Gesellschaft'', the research at the Kuffner Observatory in Vienna, the professionalization in astronomy, and the attempts of many countries to establish a southern observatory in Chile. A listing of astronomical monuments in Lilienthal and Bremen concludes the book. All papers are written in German with English abstracts.
15 aastat hiljem ehk Karl Ristikivi 90 / Janika Kronberg
Kronberg, Janika, 1963-
2003-01-01
XV Ristikivi päeva tähistamisest Ristikivi muuseumis. Karl Ristikivi Seltsi ja Eesti Võrdleva Kirjandusteaduse Assotsiatsiooni konverentsist "Eesti romaan 21. sajandi algul". Ka meenutusi K. Ristikivi loomingule pühendatud konverentsist 1987. a
Märkmeid uusima Preisi tsensuuriinstruktsiooni kohta / Karl Marx
Marx, Karl
2000-01-01
Preisi uue (1841. aasta) tsensuuriinstruktsiooni tõusikliku vaimu vastuolust vana (1818. aasta) tsensuurimääruse ratsionalismiga. Moraali ja religiooni vastuolust. Vt. ka Ain Kaalepi artiklit "Veel Karl Marxist ja tsensuurist
Kes oli rännumees Karl Feyerabend? / Urmas Sutrop
Sutrop, Urmas, 1956-
2001-01-01
Feyerabend, Karl. Kosmopolitische Wanderungen durch Preussen, Curland, Liefland, Litthauen, Vollhynien, Podolien und Schlesien, in der jahren 1795 bis 1798. In Briefen an einen Freund. Bd. 3. 1801. Eestile on pühendatud reisiraamatu 40. kiri
Karl Popper at ninety: Highlights of a lifelong intellectual quest
Selleri, Franco; van der Merwe, Alwyn
1991-12-01
On the occasion of his ninetieth birthday, Karl Popper's lifelong pursuit of answers in several areas of scientific and philosophical thinking is briefly traced, mainly with reference to excerpts from his own writings.
Karl Timoleon v. Neff / Carl Christian Vogel von Vogelstein
Vogel von Vogelstein, Carl Christian, 1788-1868
2004-01-01
"Ruskii Bibliofil", 1912, nr. 4, lk. 34; fotol tekst: "Piano di Sorrento, Villa Pisani, 20. Juli 1843". Neffi käega kirjutatud: "Karl Timoleon v. Neff geboren in Pühs in Estland im Jahre 1804 d. 2. October"
Balti Maailmanõukogu aktsioonid Helsingis 1975 / Karl Laantee
Laantee, Karl, 1927-2007
2006-01-01
1975. a. Helsingis peetud Euroopa Julgeoleku ja Koostöö Konverentsi Balti delegatsiooni liikme Karl Laantee tekst, mille ta esitas 4. augustil 1975 Balti Maailmanõukogu pressikonverentsil "Continental"hotellis Stockholmis Rootsi Eestlaste Esinduse pressiinfona
Astronaut Karl Henize with soft drink in middeck area
1985-01-01
Astronaut Karl Henize drinks from a special carbonated beverage dispenser labeled Pepsi while floating in the middeck area of the shuttle Challenger. Note the can appears to have its own built in straw.
Märkmeid uusima Preisi tsensuuriinstruktsiooni kohta / Karl Marx
Marx, Karl
2000-01-01
Preisi uue (1841. aasta) tsensuuriinstruktsiooni tõusikliku vaimu vastuolust vana (1818. aasta) tsensuurimääruse ratsionalismiga. Moraali ja religiooni vastuolust. Vt. ka Ain Kaalepi artiklit "Veel Karl Marxist ja tsensuurist
Kes oli rännumees Karl Feyerabend? / Urmas Sutrop
Sutrop, Urmas, 1956-
2001-01-01
Feyerabend, Karl. Kosmopolitische Wanderungen durch Preussen, Curland, Liefland, Litthauen, Vollhynien, Podolien und Schlesien, in der jahren 1795 bis 1798. In Briefen an einen Freund. Bd. 3. 1801. Eestile on pühendatud reisiraamatu 40. kiri
Saage tuttavaks : Elisabeth ja Karl von Hoerschelmann / Mai Levin
Levin, Mai, 1942-
2004-01-01
Kuraator M. Levin kuni 10. X 2004 Adamson-Ericu muuseumis avatud näitusest "Tuntud ja tundmatud Elisabeth von Rosendorff-Hoerschelmann ja Karl von Hoerschelmann". Enamik töid on kunstnike laste Konstantin Hoerschelmanni ja Anna Röder-Hoerschelmanni omand. Elisabeth Rosendorff (1898-1984) sündis Virumaal Maidlas eesti perekonnas, Karl von Hoerschelmann (1899-1951) Sevastoopolis saksa perekonnas
Saage tuttavaks : Elisabeth ja Karl von Hoerschelmann / Mai Levin
Levin, Mai, 1942-
2004-01-01
Kuraator M. Levin kuni 10. X 2004 Adamson-Ericu muuseumis avatud näitusest "Tuntud ja tundmatud Elisabeth von Rosendorff-Hoerschelmann ja Karl von Hoerschelmann". Enamik töid on kunstnike laste Konstantin Hoerschelmanni ja Anna Röder-Hoerschelmanni omand. Elisabeth Rosendorff (1898-1984) sündis Virumaal Maidlas eesti perekonnas, Karl von Hoerschelmann (1899-1951) Sevastoopolis saksa perekonnas
A Conversation with Karl K. Turekian
Turekian, Karl K.; Cochran, J. Kirk
2012-01-01
Editors' Note Each year, the editorial board invites a distinguished member of the oceanographic community to contribute a prefatory chapter; this year, we were delighted when Karl Turekian, Sterling Professor of Geology and Geophysics at Yale, accepted our invitation. Over the course of a long and productive career, Dr. Turekian has pursued his interests in marine and atmospheric geochemistry by using natural radioactive and radiogenic isotopes to study Earth's evolution and the impacts of global change. He has also directed both the Center for the Study of Global Change at Yale and the Yale Institute for Biospheric Studies. In this interview, conducted by his former student Kirk Cochran, Dr. Turekian tells the story of his early career and discusses some of the major scientific challenges and opportunities faced along the way. His personal account of the rise of geochemistry is a charming story of how chance events and personalities impact scientific careers. His technical insight into the future of this field is illuminating, particularly for scientific outsiders who appreciate the central role of geochemistry in discerning and understanding patterns of global change. Craig A. Carlson and Stephen J. Giovannoni, Editors [Figure: see text
Karl Marx dan Konsep Perjuangan Kelas Sosial
Directory of Open Access Journals (Sweden)
Indriaty Ismail
2012-06-01
Full Text Available ¬¬This article explores the history of the renowned world economic and political reformist, Karl Marx with a special focus on the social class concept. It also discusses to what extent that the Marx’s concept of social class struggle is capable to provide a way out to the proletariats, to free themselves from the chains of cruelty, violence and alienation in the capitalist system. Our main focal point is to scrutinize the relationship between the concepts of social class struggle and the need for a social revolution as a catalyst for the formation of a classless society. Along the way, we studied and analyzed the documents produced on the primary sources covering major works of Marx and the secondary sources consisting reviews of the Marx’s class concept. As a result, we found out that Marx’s concept of class fight is competent to represent the oppressed group to battle for their freedom rights. The Proletariat dictatorship attitude was used as their main shield to face the threat of the capitalist class. Marx’s ultimate success is realized through a burst of ideas and beliefs that supports the ideas of egalitarian Communism although many contradictions arise between the ideas of Marx and the 20th centuries Communism when they are translated into practice.
Karl Mannheim’s Jewish Question
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David Kettler
2012-04-01
Full Text Available In this paper, we explore Karl Mannheim’s puzzling failure (or refusal to address himself in any way to questions arising out of the position of Jews in Germany, either before or after the advent of Nazi rule—and this, notwithstanding the fact, first, that his own ethnic identification as a Jew was never in question and that he shared vivid experiences of anti-Semitism, and consequent exile from both Hungary and Germany, and, second, that his entire sociological method rested upon using one’s own most problematic social location—as woman, say, or youth, or intellectual—as the starting point for a reflexive investigation. It was precisely Mannheim’s convictions about the integral bond between thought grounded in reflexivity and a mission to engage in a transformative work of Bildung that made it effectively impossible for him to formulate his inquiries in terms of his way of being Jewish. It is through his explorations of the rise and fall of the intellectual as socio-cultural formation that Mannheim investigates his relations to his Jewish origins and confronts the disaster of 1933. The key to our puzzle is to be found in the theory of assimilation put forward in the dissertation of his student, Jacob Katz.
Information Systems Foundations - Karl Popper's third world
Directory of Open Access Journals (Sweden)
Craig McDonald
2002-11-01
Full Text Available The various information professions have matured separately over the years, developing different bodies of theory and practice to meet their evolving purposes and needs. A problem arises however, when different information professions address the same knowledge domain and there is no explicit correspondence between the conceptual structures embedded independently in each. In this situation, a knowledge worker involved in the domain is faced with a range of possibly incompatible structures presented in different forms by a range of information professions. This is a common problem that is being exacerbated by the explosion in information production and the widening access to information distribution technology, notably the World Wide Web. Information Systems now need to combine the best of what the information professions in a domain have to offer the domain’s knowledge workers. This paper examines the problem by exploring one of the foundations of the information disciplines - Karl Popper’s 3 Worlds theory, applying it to a case study and suggesting that the Information Systems discipline alone has a sufficiently broad agenda to integrate the various Informatics themes needed to support today’s knowledge workers.
Schwarzschild and Kerr Solutions of Einstein's Field Equation -- an introduction
Heinicke, Christian; .,
2015-01-01
Starting from Newton's gravitational theory, we give a general introduction into the spherically symmetric solution of Einstein's vacuum field equation, the Schwarzschild(-Droste) solution, and into one specific stationary axially symmetric solution, the Kerr solution. The Schwarzschild solution is unique and its metric can be interpreted as the exterior gravitational field of a spherically symmetric mass. The Kerr solution is only unique if the multipole moments of its mass and its angular momentum take on prescribed values. Its metric can be interpreted as the exterior gravitational field of a suitably rotating mass distribution. Both solutions describe objects exhibiting an event horizon, a frontier of no return. The corresponding notion of a black hole is explained to some extent. Eventually, we present some generalizations of the Kerr solution.
Dirac dynamical resonance states around Schwarzschild black holes
Zhou, Xiang-Nan; Yang, Ke; Liu, Yu-Xiao
2013-01-01
Recently, a novel kind of scalar wigs around Schwarzschild black holes---scalar dynamical resonance states were introduced in [Phys. Rev. D 84, 083008 (2011)] and [Phys. Rev. Lett. 109, 081102 (2012)]. In this paper, we investigate the existence and evolution of Dirac dynamical resonance states. First we look for stationary resonance states of a Dirac field around a Schwarzchild black hole by using the Schrodinger-like equations reduced from the Dirac equation in Schwarzschild spacetime. Then Dirac pseudo-stationary configurations are constructed from the stationary resonance states. We use these configurations as initial data and investigate their numerical evolutions and energy decay. These dynamical solutions are the so-called "Dirac dynamical resonance states". It is found that the energy of the Dirac dynamical resonance states shows an exponential decay. The decay rate of energy is affected by the resonant frequency, the mass of Dirac field, the total angular momentum, and the spin-orbit interaction. In ...
Perturbations on steady spherical accretion in Schwarzschild geometry
Naskar, Tapan; Bhattacharjee, Jayanta K; Ray, Arnab K
2007-01-01
The stationary background flow in the spherically symmetric infall of a compressible fluid, coupled to the space-time defined by the static Schwarzschild metric, has been subjected to linearized perturbations. The perturbative procedure is based on the continuity condition and it shows that the coupling of the flow with the geometry of space-time brings about greater stability for the flow, to the extent that the amplitude of the perturbation, treated as a standing wave, decays in time, as opposed to the amplitude remaining constant in the Newtonian limit. In qualitative terms this situation simulates the effect of a dissipative mechanism in the classical Bondi accretion flow, defined in the Newtonian construct of space and time. As a result of this approach it becomes impossible to define an acoustic metric for a conserved spherically symmetric flow, described within the framework of Schwarzschild geometry. In keeping with this view, the perturbation, considered separately as a high-frequency travelling wave...
Exact, Schwarzschild-like solution for Yang-Mills theory
Energy Technology Data Exchange (ETDEWEB)
Singleton, D.
1995-04-01
Exploiting the connection between general relativity and Yang-Mills theory an exact, Schwarzchild-like solution is given for an SU(N) gauge field coupled to a scalar field in the Bogomolny, Prasad, Sommerfield limit. The SU(2) solution is found using the second order Euler-Lagrange formalism, while the SU(N) generalization is given using the first order Bogomolny formalism. In analogy with the Schwarzschild solution of general relativity, these Yang-Mills solutions possess an event horizon with respect to the SU(N) charge. It is conjectured that this may be the confinement mechanism for QCD, since just as a Schwarzschild black hole will permanently confine anything which carries the charge of general relativity (mass-energy), so this Yang-Mills solution will confine any particle which carries the SU(N) charge.
Comment on "Chaotic orbits for spinning particles in Schwarzschild spacetime"
Lukes-Gerakopoulos, Georgios
2016-11-01
The astrophysical relevance of chaos for a test particle with spin moving in Schwarzschild spacetime was the objective of C. Verhaaren and E. W. Hirschmann in [Phys. Rev. D 81, 124034 (2010)]. Even if the results of the study might appear to be qualitatively in agreement with similar works, the study presented in their work suffers both from theoretical and technical issues. These issues are discussed in this comment.
Linear perturbations of a Schwarzschild blackhole by thin disc - convergence
Čížek, P.; Semerák, O.
2012-07-01
In order to find the perturbation of a Schwarzschild space-time due to a rotating thin disc, we try to adjust the method used by [4] in the case of perturbation by a one-dimensional ring. This involves solution of stationary axisymmetric Einstein's equations in terms of spherical-harmonic expansions whose convergence however turned out questionable in numerical examples. Here we show, analytically, that the series are almost everywhere convergent, but in some regions the convergence is not absolute.
Schwarzschild-de Sitter Metric and Inertial Beltrami Coordinates
Sun, Li-Feng; Deng, Ya; Huang, Wei; Hu, Sen
2013-01-01
Under consideration of coordinate conditions, we get the Schwarzschild-Beltrami-de Sitter (S-BdS) metric solution of the Einstein field equations with a cosmological constant $\\Lambda$. A brief review to the de Sitter invariant special relativity (dS-SR), and de Sitter general relativity (dS-GR, or GR with a $\\Lambda$) is presented. The Beltrami metric $B_{\\mu\
Relativistic sonic geometry for isothermal accretion in the Schwarzschild metric
Shaikh, Md Arif; Firdousi, Ivleena; Das, Tapas K
2016-01-01
The velocity potential, mass accretion rate and the Bernoulli's Constant corresponding to the general relativistic isothermal accretion in the Schwarzschild metric have been linearly perturbed, both for spherical as well as the axially symmetric flow to demonstrate the emergence of the embedded curved sonic manifold. Except the conformal factors, the relativistic acoustic geometry remains invariant irrespective of the physical quantity getting perturbed. The acoustic surface gravity has been ...
Second order perturbations of a Schwarzschild black hole
1995-01-01
We study the even-parity $\\ell=2$ perturbations of a Schwarzschild black hole to second order. The Einstein equations can be reduced to a single linear wave equation with a potential and a source term. The source term is quadratic in terms of the first order perturbations. This provides a formalism to address the validity of many first order calculations of interest in astrophysics.
Karl Barth and the future of dogmatic theology
Directory of Open Access Journals (Sweden)
Alasdair I.C. Heron
2002-11-01
Full Text Available The article discusses Karl Barth’s contribution to dogmatic theology. It describes Karl Barth’s personality and shows how his theology was put to practice in writing, in teaching, in debate, in conflict, in friendship and in opposition. Some negative comments on Barth are for example levelled at his liturgical insensitivity, unbalanced and exclusive emphasis on preaching, and his individualistic dislike of the established church, its governing structures and baptismal practice. The article focuses on Barth’s impulses for the discipline of dogmatics and demonstrates developments and directions in his work. Critically reservations regarding instances where it might seem better for theologians not to follow Barth, are specified. The article also offers a glimpse into the future of dogmatic theology seen through the lens of Karl Barth.
Constructing Marxism: Karl Kautsky and the French Revolution
DEFF Research Database (Denmark)
Nygaard, Bertel
2009-01-01
Karl Kautsky's writings on the French Revolution were crucial to the construction not only of the Marxist interpretation of the Revolution, which was perhaps the most important reference point for the historiography of that event during the 20th century, but even of Marxism itself as a comprehens......Karl Kautsky's writings on the French Revolution were crucial to the construction not only of the Marxist interpretation of the Revolution, which was perhaps the most important reference point for the historiography of that event during the 20th century, but even of Marxism itself...
Mozart, Karl Barth, og den kristne troslæren
DEFF Research Database (Denmark)
Petersen, Nils Holger
2010-01-01
En diskussion af Karl Barths teologiske brug af W.A.Mozart i den kirchliche Dogmatik med kontekstuel inddragelse af en til en vis grad tilsvarende overordnet diskussion af Mozart, skrevet af en samtidig musiker, den fremtrædende Mozart-dirigent Ferenc Fricsay. ......En diskussion af Karl Barths teologiske brug af W.A.Mozart i den kirchliche Dogmatik med kontekstuel inddragelse af en til en vis grad tilsvarende overordnet diskussion af Mozart, skrevet af en samtidig musiker, den fremtrædende Mozart-dirigent Ferenc Fricsay. ...
Rediscussion of the Stability Problem of the Schwarzschild Black Hole
Institute of Scientific and Technical Information of China (English)
Tian Gui-Hua
2006-01-01
@@ We use the Kruskal time coordinate T to define the initial time. By this way, the stability study naturally becomes the one connected with the two regions, i.e. the white-hole-connected region and the black-hole-connected region.The union of the two regions covers the Schwarzschild space-time (r ≥ 2m). We also obtain the very reasonable conclusion: the white-hole-connected region is unstable and the black-hole-connected region is stable.
Effective horizons for quantum communication in a Schwarzschild spacetime
Hosler, Dominic; Kok, Pieter
2011-01-01
Communication between a free-falling observer and an observer hovering above the Schwarzschild horizon of a black hole suffers from Unruh-Hawking noise, which degrades communication channel capacities. Ignoring time dilation, which affects all channels equally, we show that for bosonic communication using single and dual rail encoding the classical channel capacity reaches a finite value and the quantum channel capacity falls off exponentially. The latter defines an effective horizon, beyond which quantum communication becomes exponentially resource inefficient. The characteristic length scale associated with this quantum horizon depends on the mass of the black hole and the frequency of the communication channel.
Asymptotic Quasinormal Frequencies of d-dimensional Schwarzschild Black Holes
Birmingham, D
2003-01-01
We determine the quasinormal frequencies for all gravitational perturbations of the d-dimensional Schwarzschild black hole, in the infinite damping limit. Using the potentials for gravitational perturbations derived recently by Ishibashi and Kodama, we show that in all cases the asymptotic real part of the frequency is proportional to the Hawking temperature with a coefficient of log 3. Via the correspondence principle, this leads directly to an equally spaced entropy spectrum. We comment on the possible implications for the spacing of eigenvalues of the Virasoro generator in the associated near-horizon conformal algebra.
Tunneling of massive particles from noncommutative Schwarzschild black hole
Miao, Yan-Gang; Zhang, Shao-Jun
2010-01-01
We apply the generalization of the Parikh-Wilczek method to the tunneling of massive particles from noncommutative Schwarzschild black holes. By deriving the equation of radial motion of the tunneling particle directly, we calculate the emission rate which is shown to be dependent on the noncommutative parameter besides the energy and mass of the tunneling particle. After equating the emission rate to the Boltzmann factor, we obtain the modified Hawking temperature which relates to the noncommutativity and recovers the standard Hawking temperature in the commutative limit. We also discuss the entropy of the noncommutative Schwarzchild black hole and its difference after and before a massive particle's emission.
Schwarzschild scalar wigs: spectral analysis and late time behavior
Barranco, Juan; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Nunez, Dario; Sarbach, Olivier
2013-01-01
Using the Green's function representation technique, the late time behavior of localized scalar field distributions on Schwarzschild spacetimes is studied. Assuming arbitrary initial data we perform a spectral analysis, computing the amplitude of each excited quasi-bound mode without the necessity of performing dynamical evolutions. The resulting superposition of modes is compared with a traditional numerical evolution with excellent agreement; therefore, we have an efficient way to determine final black hole wigs. The astrophysical relevance of the quasi-bound modes is discussed in the context of scalar field dark matter models and the axiverse.
Drude-Schwarzschild Metric and the Electrical Conductivity of Metals
Directory of Open Access Journals (Sweden)
Silva P. R.
2014-07-01
Full Text Available Starting from a string with a length equal to the electron mean free path and having a unit cell equal to the Compton length of the electron, we construct a Schwarzschild-like metric. We found that this metric has a surface horizon with radius equal to the electron mean free path and its Bekenstein-like entropy is proportional to the number of squared unit cells contained in this spherical surface. The Hawking temperature is inversely proportional to the perimeter of the maximum circle of this sphere. Also, interesting analogies on some features of the particle physics are examined.
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.
Partition function of massless scalar field in Schwarzschild background
Sanyal, Abhik Kumar
2014-01-01
Using thermal value of zeta function instead of zero temperature, the partition function of quantized fields in arbitrary stationary backgrounds was found to be independent of undetermined regularization constant in even-dimension and the long drawn problem associated with the trace anomaly effect had been removed. Here, we explicitly calculate the expression for the coincidence limit so that the technique may be applied in some specific problems. A particular problem dealt with here is to calculate the partition function of massless scalar field in Schwarzschild background.
Sectional Curvature Bounds in Gravity: Regularisation of the Schwarzschild Solution
Schuller, F P; Schuller, Frederic P.; Wohlfarth, Mattias N.R.
2004-01-01
A general geometrical scheme is presented for the construction of novel classical gravity theories whose solutions obey two-sided bounds on the sectional curvatures along certain subvarieties of the Grassmannian of two-planes. The motivation to study sectional curvature bounds comes from their equivalence to bounds on the acceleration between nearby geodesics. A universal minimal length scale is a necessary ingredient of the construction, and an application of the kinematical framework to static, spherically symmetric spacetimes shows drastic differences to the Schwarzschild solution of general relativity by the exclusion of spacelike singularities.
Sectional curvature bounds in gravity: regularisation of the Schwarzschild singularity
Energy Technology Data Exchange (ETDEWEB)
Schuller, Frederic P. [Perimeter Institute for Theoretical Physics, Waterloo N2J 2W9, Ontario (Canada)]. E-mail: fschuller@perimeterinstitute.ca; Wohlfarth, Mattias N.R. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)]. E-mail: m.n.r.wohlfarth@damtp.cam.ac.uk
2004-10-18
A general geometrical scheme is presented for the construction of novel classical gravity theories whose solutions obey two-sided bounds on the sectional curvatures along certain subvarieties of the Grassmannian of two-planes. The motivation to study sectional curvature bounds comes from their equivalence to bounds on the acceleration between nearby geodesics. A universal 'minimal length' scale is a necessary ingredient of the construction, and an application of the kinematical framework to static, spherically symmetric spacetimes shows drastic differences to the Schwarzschild solution of general relativity by the exclusion of spacelike singularities.
Complex Normal-mode Frequencies of External Perturbations in Generalized Schwarzschild Geometry
Institute of Scientific and Technical Information of China (English)
YUAN Ning-Yi; LI Xin-Zhou
2000-01-01
A moditied Wentzel-Kramers-Brillouin approach is used to determine the complex normal-mode frequencies of external perturbations in generalized Schwarzschild geometry. In the λ= 1 case (Schwarzschild geometry), the agreement with other methods is excellent for the low-lying modes. On the contrary, the λ ≠ 1 case of this geometry is unstable against external perturbations
Hannah Arendt and Karl Jaspers: The Time of Friendship
Nixon, Jon
2016-01-01
This paper provides an introduction to the enduring friendship between Hannah Arendt and Karl Jaspers. It shows how their intellectual development as public educators was sustained by their ongoing dialogue which flourished not in spite of but because of their huge differences of circumstance and personality. This friendship between two renowned…
Hannah Arendt and Karl Jaspers: The Time of Friendship
Nixon, Jon
2016-01-01
This paper provides an introduction to the enduring friendship between Hannah Arendt and Karl Jaspers. It shows how their intellectual development as public educators was sustained by their ongoing dialogue which flourished not in spite of but because of their huge differences of circumstance and personality. This friendship between two renowned…
"Art, Imagination, Storytelling": An Interview with Karl Kroeber
Mallick, Michael
2012-01-01
This article presents an interview with Karl Kroeber that was originally published in "English Department Updates" (Fall 2009), a semiannual alumni newsletter of the Columbia University Department of English & Comparative Literature. In this interview, Kroeber, who taught at Columbia for 57 years, discusses the range of courses he…
Chef's Signature - Karl Breen, Locks Brasserie, Dublin : Video
2015-01-01
12 Hour Octopus, Black Garlic, Calamansi Mayo, Tamarind and Salted Celeriac is one of the dishes on Karl Breen's menu at Locks Brasserie in Dublin, and it's a dish that shows a cook in control of his art. Reproduced with kind permission from John & Sally McKenna. 3.16 mins
Kokast ja Eesti Naisest / Karl Martin Sinijärv
Sinijärv, Karl Martin, 1971-
2006-01-01
Sisaldab retsepte: Ilmar Laabani lintnuudlid põdralihaga ; Jan Kausi krevetipasta ; Kauksi Ülle liharullid ; Jürgen Rooste banaanikana ; KMSi [Karl Martin Sinijärve] öine lugemisliud ; Asko Künnapi suvikõrvits ; Ilmar Laabani Margarita
KARL MAYER——We Care about Your Future
Institute of Scientific and Technical Information of China (English)
2011-01-01
As one of the leading manufacturers of warp knitting and warp preparation machines,KARL MAYER will be presenting at this year＇s ITMA 2011 in Barcelona.For the first time,all the company＇s business units will be represented on the same stand in hall 3,stand B 153-157,on an area of 1400 square-meter.
Karl Popper and Jean Piaget: A Rationale for Constructivism
Harlow, Steve; Cummings, Rhoda; Aberasturi, Suzanne M.
2006-01-01
The current faddish use of the term constructivism has taken on as many different definitions as the number of people attempting to define it. This essay clarifies the meaning of constructivism through an examination of Karl Popper's and Jean Piaget's theories. The authors provide a rationale for the use of Popper's paradigm of "Three Worlds" and…
The Reference Process and the Philosophy of Karl Popper.
Neill, S. D.
1985-01-01
Two aspects of Karl Popper's philosophy are applied to reference process: process is viewed as series of problem-solving situations amenable to analysis using Popper's problem-solving schema. Reference interview is analyzed in context of Popper's postulate that books contain autonomous world of ideas existing apart from mind of knower. (30…
The dangerous misconceptions of Sir Karl Raimund Popper
Svozil, K
2002-01-01
Insofar as Sir Karl Raimund Popper's writings deal with political statements, they are evident; yet insofar as they deal with scientific issues, they are incorrect and misleading. If applied to the concrete implementation of science, such as distribution of research funds and (peer) review, they would seriously hamper progress.
Karl XII rootsi kirjanduses / Anu Saluäär
Saluäär, Anu, 1948-
2008-01-01
Valikuline ülevaade Karl XII-st rootsi kirjanduses: Israel Holmström, Esaias Tegner, Zacharias Topelius, Carl Snoilsky, Anders Fryxell, Verner von Heidenstam, Harald Hiärne, Frans G. Bengtsson. Sisaldab märkusi joonealustes viidetes
Halstead, Evan
2011-01-01
We investigate the time evolution of the temperature and entropy of a gravitationally collapsing de Sitter Schwarzschild domain wall as seen by an asymptotic observer. Recent work has completed this analysis for Schwarzschild and 3+1 BTZ domain walls. There were some striking qualitative differences between the two. Specifically, the BTZ domain wall exhibited a decrease in entropy over time. However, it contained both a cosmological constant and a different topology from the Schwarzschild domain wall, and we wish to isolate which of these is responsible for the qualitative differences. Hence, we will study the de Sitter Schwarzschild domain wall, as it has identical topology to the Schwarzschild domain wall yet also contains a cosmological constant. We utilize a wavefunctional approach where we couple a scalar field to the background of the collapsing domain wall and determine the spectrum of the radiation as a function of time. The fact that the distribution is thermal allows for the determination of the tem...
Gravitational lensing of massive particles in Schwarzschild gravity
Liu, Xionghui; Yang, Nan; Jia, Junji
2016-09-01
Both massless light ray and objects with nonzero mass experience trajectory bending in a gravitational field. In this work the bending of trajectories of massive objects in a Schwarzschild spacetime and the corresponding gravitational lensing (GL) effects are studied. A particle sphere for Schwarzschild black hole (BH) is found with its radius a simple function of the particle velocity and proportional to the BH mass. A single master formula for both the massless and massive particle bending angle is found, in the form of an elliptic function depending only on the velocity and impact parameter. This bending angle is expanded in both large and small velocity limits and large and small impact parameter limits. The corresponding deflection angle for weak and strong GL of massive particles are analyzed, and their corrections to the light ray deflection angles are obtained. The dependence of the deflection angles on the source angle and the particle speed is investigated. Finally we discuss the potential applications of the results in hypervelocity star observations and in determining mass/mass hierarchy of slow particles/objects.
Towards a Supersymmetric Generalization of the Schwarzschild Black Hole
López-Domínguez, J C; Zacarías, S
2009-01-01
The Wheeler-DeWitt (WDW) equation for the Kantowski-Sachs model can also be understood as the WDW-equation corresponding to the Schwarzschild black hole due to the well known diffeomorphism between these two metrics. The WDW-equation and its solutions are ``ignorant'' of the coordinate patch one is using, only by imposing coordinate conditions we can differentiate between cosmological and black hole models. At that point, the foliation parameter $t$ or $r$ will appear in the solution of interest. In this work we supersymmetrize this WDW-equation obtaining an extra term in the potential with two possible signs. The WKB method is then applied, given rise to two classical equations. It is shown that the event horizon can never be reached because, very near to it the extra term in the potential, for each one of the equations, is more relevant than the one that corresponds to Schwarzschild. One can then study the asymptotic cases in which one of the two terms in the Hamiltonian dominates the behavior. One of them ...
Decay of linear waves on higher dimensional Schwarzschild black holes
Schlue, Volker
2010-01-01
In this paper we consider solutions to the linear wave equation on higher dimensional Schwarzschild black hole spacetimes and prove robust nondegenerate energy decay estimates that are in principle required in a nonlinear stability problem. More precisely, it is shown that for solutions to the wave equation \\Box_g\\phi=0 on the domain of outer communications of the Schwarzschild spacetime manifold (M^n_m, g) (where n >= 3 is the spatial dimension, and m > 0 is the mass of the black hole) the associated energy flux E[\\phi](\\Sigma_\\tau) through a foliation of hypersurfaces (\\Sigma_\\tau) (terminating at future null infinity and to the future of the bifurcation sphere) decays, E[\\phi](\\Sigma_\\tau) 0 where \\Sigma_\\tau^R denotes the hypersurface (\\Sigma_\\tau) truncated at an arbitrarily large fixed radius R < \\infty provided the higher order energy D_\\delta on \\Sigma_0 is finite. We conclude our paper by interpolating between these two results to obtain the pointwise estimate |\\phi|_{\\Sigma_\\tau^R} <= (C D'_\\...
Thermodynamics of Schwarzschild-Beltrami-de Sitter black hole
Liu, Hang; Meng, Xin-He
2017-09-01
In this paper, we investigate the thermodynamical properties of Schwarzschild-Beltrami-de Sitter (S-BdS) black hole introduced by Yan et al. in 2013 by introducing inertial Beltrami coordinates to traditional non-inertial Schwarzschild-de Sitter (S-dS) metric which is the exact static spherical symmetry solution of Einstein equation with a positive cosmological constant Λ. Based on this new metric, we compute entropy on all horizons and we give the entropy bound of the black hole. Hawking temperatures are calculated by considering a perturbation to entropy relations due to that the spacetime described by these inertial coordinates is no longer a stationary spacetime in which surface gravity related to Hawking temperature is defined well on killing horizon. We also get the Smarr relations and the first law of thermodynamics. We find that the S-BdS black hole seems to have similar thermodynamical properties to S-dS black hole in the comparison between their corresponding thermodynamical quantities, although the new black hole metric is described by inertial coordinates which exclude the effects of inertial force.
The Compton-Schwarzschild relations in higher dimensions
Lake, Matthew J
2016-01-01
In three spatial dimensions, the Compton wavelength $(R_C \\propto M$) and Schwarzschild radius $(R_S \\propto M^{-1}$) are dual under the transformation $M \\rightarrow M_{P}^2/M$, where $M_{P}$ is the Planck mass. This suggests that there is a fundamental link -- termed the Black Hole Uncertainty Principle or Compton-Schwarzschild correspondence -- between elementary particles in the $M M_{P}$ regime. In the presence of $n$ extra dimensions, compactified on some scale $R_E$, one expects $R_S \\propto M^{1/(1+n)}$ for $R < R_E$, which breaks this duality. However, it may be restored in some circumstances because the effective Compton wavelength depends on the form of the $(3+n)$-dimensional wavefunction. If this is spherically symmetric, then one still has $R_C \\propto M^{-1}$, as in the $3$-dimensional case. The effective Planck length is then increased and the Planck mass reduced, allowing the possibility of TeV quantum gravity and black hole production at the LHC. However, if the wave function is pancaked...
Optical anisotropy of schwarzschild metric within equivalent medium framework
Khorasani, Sina; Rashidian, Bizhan
2010-04-01
It is has been long known that the curved space in the presence of gravitation can be described as a non-homogeneous anisotropic medium in flat geometry with different constitutive equations. In this article, we show that the eigenpolarizations of such medium can be exactly solved, leading to a pseudo-isotropic description of curved vacuum with two refractive index eigenvalues having opposite signs, which correspond to forward and backward travel in time. We conclude that for a rotating universe, time-reversal symmetry is broken. We also demonstrate the applicability of this method to Schwarzschild metric and derive exact forms of refractive index. We derive the subtle optical anisotropy of space around a spherically symmetric, non-rotating and uncharged blackhole in the form of an elegant closed-form expression, and show that the refractive index in such a pseudo-isotropic system would be a function of coordinates as well as the direction of propagation. Corrections arising from such anisotropy in the bending of light are shown and a simplified system of equations for ray-tracing in the equivalent medium of Schwarzschild metric is found.
The linear stability of the Schwarzschild solution to gravitational perturbations
Dafermos, Mihalis; Rodnianski, Igor
2016-01-01
We prove in this paper the linear stability of the celebrated Schwarzschild family of black holes in general relativity: Solutions to the linearisation of the Einstein vacuum equations around a Schwarzschild metric arising from regular initial data remain globally bounded on the black hole exterior and in fact decay to a linearised Kerr metric. We express the equations in a suitable double null gauge. To obtain decay, one must in fact add a residual pure gauge solution which we prove to be itself quantitatively controlled from initial data. Our result a fortiori includes decay statements for general solutions of the Teukolsky equation (satisfied by gauge-invariant null-decomposed curvature components). These latter statements are in fact deduced in the course of the proof by exploiting associated quantities shown to satisfy the Regge--Wheeler equation, for which appropriate decay can be obtained easily by adapting previous work on the linear scalar wave equation. The bounds on the rate of decay to linearised ...
Schwarzschild-Couder Telescope for the Cherenkov Telescope Array
Meagher, Kevin J
2014-01-01
The Cherenkov Telescope Array (CTA) is the next major ground-based observatory for gamma-ray astronomy. With CTA gamma-ray sources will be studied in the very-high energy gamma-ray range of a few tens of GeV to 100 TeV with up to ten times better sensitivity than available with current generation instruments. We discuss the proposed US contribution to CTA that comprises imaging atmospheric Cherenkov telescope with Schwarzschild-Couder (SC) optics. Key features of the SC telescope are a wide field of view of eight degrees, a finely pixelated camera with silicon photomultipliers as photon detectors, and a compact and power efficient 1 GS/s readout. The progress in both the optical system and camera development are discussed in this paper.
On the twin paradox in static spacetimes: I. Schwarzschild metric
Sokolowski, Leszek M
2012-01-01
Motivated by a conjecture put forward by Abramowicz and Bajtlik we reconsider the twin paradox in static spacetimes. According to a well known theorem in Lorentzian geometry the longest timelike worldline between two given points is the unique geodesic line without points conjugate to the initial point on the segment joining the two points. We calculate the proper times for static twins, for twins moving on a circular orbit (if it is a geodesic) around a centre of symmetry and for twins travelling on outgoing and ingoing radial timelike geodesics. We show that the twins on the radial geodesic worldlines are always the oldest ones and we explicitly find the conjugate points (if they exist) outside the relevant segments. As it is of its own mathematical interest, we find general Jacobi vector fields on the geodesic lines under consideration. In the first part of the work we investigate Schwarzschild geometry.
Wave Optics in Black Hole Spacetimes: Schwarzschild Case
Nambu, Yasusada
2015-01-01
We investigate the wave optics in the Schwarzschild spacetime. Applying the standard formalism of wave scattering problems, the Green function represented by the sum over the partial waves is evaluated using the Poisson sum formula. The effect of orbiting scattering due to the unstable circular orbit for null rays is taken into account as the contribution of the Regge poles of the scattering matrix and the asymptotic form of the scattering wave is obtained in the eikonal limit. Using this wave function, images of the black hole illuminated by a point source are reconstructed. We also discuss the wave effect in the frequency domain caused by the interference between the direct rays and the winding rays.
Lamb Shift for static atoms outside a Schwarzschild black hole
Zhou, Wenting
2010-01-01
We study, by separately calculating the contributions of vacuum fluctuations and radiation reaction to the atomic energy level shift, the Lamb shift of a static two-level atom interacting with real massless scalar fields in the Boulware, Unruh and Hartle-Hawking vacuums outside a Schwarzschild black hole. We find that in the Boulware vacuum, the Lamb shift gets a correction arising as a result of the backscattering of vacuum field modes off the space-time curvature, which is reminiscent of the correction to the Lamb shift induced by the presence of cavities. However, when the Unruh and Hartle-Hawking vacua are concerned, our results show that the Lamb shift behaves as if the atom were irradiated by a thermal radiation or immersed in a thermal bath at the Hawking temperature, depending on whether the scalar field is in the Unruh or the Hartle-Hawking vacuum. Remarkably, the thermal radiation is always backscattered by the space-time geometry.
Phenomenological loop quantum geometry of the Schwarzschild black hole
Chiou, Dah-Wei
2008-01-01
The interior of a Schwarzschild black hole is investigated at the level of phenomenological dynamics with the discreteness corrections of loop quantum geometry implemented in two different improved quantization schemes. In one scheme, the classical black hole singularity is resolved by the quantum bounce, which bridges the black hole interior with a white hole interior. In the other scheme, the classical singularity is resolved and the event horizon is also diffused by the quantum bounce. Jumping over the quantum bounce, the black hole gives birth to a baby black hole with a much smaller mass. This lineage continues as each classical black hole brings forth its own descendant in the consecutive classical cycle, giving the whole extended spacetime fractal structure, until the solution eventually descends into deep Planck regime, signaling a breakdown of the semiclassical description. The issues of scaling symmetry and no-hair theorem are also discussed.
Energy in the Schwarzschild-de Sitter Spacetime
Salti, M; Aydogdu, Oktay; Salti, Mustafa
2006-01-01
The energy (due to matter and fields including gravitation) of the Schwarzschild-de Sitter spacetime is investigated by using the Moller energy-momentum definition in both general relativity and teleparallel gravity. We found the same energy distribution for a given metric in both of these different gravitation theories. It is also independent of the teleparallel dimensionless coupling constant, which means that it is valid in any teleparallel model. Our results sustain that (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Moller energy-momentum complex is a powerful concept of energy and momentum.
Spin-geodesic deviations in the Schwarzschild spacetime
Bini, Donato; Geralico, Andrea; Jantzen, Robert T.
2011-04-01
The deviation of the path of a spinning particle from a circular geodesic in the Schwarzschild spacetime is studied by an extension of the idea of geodesic deviation. Within the Mathisson-Papapetrou-Dixon model and assuming the spin parameter to be sufficiently small so that it makes sense to linearize the equations of motion in the spin variables as well as in the geodesic deviation, the spin-curvature force adds an additional driving term to the second order system of linear ordinary differential equations satisfied by nearby geodesics. Choosing initial conditions for geodesic motion leads to solutions for which the deviations are entirely due to the spin-curvature force, and one finds that the spinning particle position for a given fixed total spin oscillates roughly within an ellipse in the plane perpendicular to the motion, while the azimuthal motion undergoes similar oscillations plus an additional secular drift which varies with spin orientation.
Spin-geodesic deviations in the Schwarzschild spacetime
Bini, Donato; Jantzen, Robert T
2014-01-01
The deviation of the path of a spinning particle from a circular geodesic in the Schwarzschild spacetime is studied by an extension of the idea of geodesic deviation. Within the Mathisson-Papapetrou-Dixon model and assuming the spin parameter to be sufficiently small so that it makes sense to linearize the equations of motion in the spin variables as well as in the geodesic deviation, the spin-curvature force adds an additional driving term to the second order system of linear ordinary differential equations satisfied by nearby geodesics. Choosing initial conditions for geodesic motion leads to solutions for which the deviations are entirely due to the spin-curvature force, and one finds that the spinning particle position for a given fixed total spin oscillates roughly within an ellipse in the plane perpendicular to the motion, while the azimuthal motion undergoes similar oscillations plus an additional secular drift which varies with spin orientation.
Schwarzschild black hole as particle accelerator of spinning particles
Zaslavskii, O B
2016-01-01
It is shown that in the Schwarzschild background there exists direct counterpart of the Ba\\~{n}ados-Silk-West effect for spinning particles. This means that if two particles collide near the black hole horizon, their energy in the centre of mass frame can grow unbound. In doing so, the crucial role is played by so-called near-critical trajectories when particle's parameters are almost fine-tuned. Direct scenario of the collision under discussion is possible with restriction on the energy-to-mass ratio \\thinspace $E/m<\\frac{1}{2\\sqrt{3}}$ only. However, if one takes into account multiple scattering, this becomes possible for $E\\geq m$ as well.
Schwarzschild models of the Sculptor dSph galaxy
Directory of Open Access Journals (Sweden)
van de Ven G.
2012-02-01
Full Text Available We have developed a spherically symmetric dynamical model of a dwarf spheroidal galaxy using the Schwarzschild method. This type of modelling yields constraints both on the total mass distribution (e.g. enclosed mass and scale radius as well as on the orbital structure of the system modelled (e.g. velocity anisotropy. Therefore not only can we derive the dark matter content of these systems, but also explore possible formation scenarios. Here we present preliminary results for the Sculptor dSph. We find that the mass of Sculptor within 1 kpc is 8.5 × 107±0.05 M๏, its anisotropy profile is tangentially biased and slightly more isotropic near the center. For an NFW profile, the preferred concentration (~15 is compatible with cosmological models. Very cuspy density profiles (steeper than NFW are strongly disfavoured for Sculptor.
Wave optics in black hole spacetimes: the Schwarzschild case
Nambu, Yasusada; Noda, Sousuke
2016-04-01
We investigate the wave optics in the Schwarzschild spacetime. Applying the standard formalism of wave-scattering problems, the Green function represented by the sum over the partial waves is evaluated using the Poisson sum formula. The effect of orbiting scattering due to the unstable circular orbit for null rays is taken into account as the contribution of the Regge poles of the scattering matrix and the asymptotic form of the scattering wave is obtained in the eikonal limit. Using this wave function, images of the black hole illuminated by a point source are reconstructed. We also discuss the wave effect in the frequency domain caused by the interference between the direct and the winding rays.
Silicon Photomultiplier Camera for Schwarzschild-Couder Cherenkov Telescopes
Vandenbroucke, J
2014-01-01
The Cherenkov Telescope Array (CTA) is an atmospheric Cherenkov observatory that will image the cosmos in very-high-energy gamma rays. CTA will study the highest-energy particle accelerators in the Universe and potentially confirm the particle nature of dark matter. We have designed an innovative Schwarzschild-Couder telescope which uses two mirrors to achieve excellent optical performance across a wide field of view. The small plate scale of the dual-mirror optics enables a compact camera which uses modern technology including silicon photomultipliers and the TARGET application-specific integrated circuit to read out a finely pixelated focal plane of 11,328 channels with modest weight, volume, cost, and power consumption. The camera design is hierarchical and modular at each level, enabling robust construction, operation, and maintenance. A prototype telescope is under construction and will be commissioned at the VERITAS site in Arizona. An array of such telescopes will provide excellent angular resolution a...
The Compton-Schwarzschild correspondence from extended de Broglie relations
Energy Technology Data Exchange (ETDEWEB)
Lake, Matthew J. [The Institute for Fundamental Study, “The Tah Poe Academia Institute' ,Naresuan University, Phitsanulok 65000 (Thailand); Thailand Center of Excellence in Physics, Ministry of Education,Bangkok 10400 (Thailand); Carr, Bernard [School of Physics and Astronomy, Queen Mary University of London,Mile End Road, London E1 4NS (United Kingdom)
2015-11-17
The Compton wavelength gives the minimum radius within which the mass of a particle may be localized due to quantum effects, while the Schwarzschild radius gives the maximum radius within which the mass of a black hole may be localized due to classial gravity. In a mass-radius diagram, the two lines intersect near the Planck point (l{sub P},m{sub P}), where quantum gravity effects become significant. Since canonical (non-gravitational) quantum mechanics is based on the concept of wave-particle duality, encapsulated in the de Broglie relations, these relations should break down near (l{sub P},m{sub P}). It is unclear what physical interpretation can be given to quantum particles with energy E≫m{sub P}c{sup 2}, since they correspond to wavelengths λ≪l{sub P} or time periods τ≪t{sub P} in the standard theory. We therefore propose a correction to the standard de Broglie relations, which gives rise to a modified Schrödinger equation and a modified expression for the Compton wavelength, which may be extended into the region E≫m{sub P}c{sup 2}. For the proposed modification, we recover the expression for the Schwarzschild radius for E≫m{sub P}c{sup 2} and the usual Compton formula for E≪m{sub P}c{sup 2}. The sign of the inequality obtained from the uncertainty principle reverses at m≈m{sub P}, so that the Compton wavelength and event horizon size may be interpreted as minimum and maximum radii, respectively. We interpret the additional terms in the modified de Broglie relations as representing the self-gravitation of the wave packet.
Ehasalu, Pia, 1964-
2004-01-01
Kuninganna Kristiina portreest lapsena (1638). Arvatav autor: Rootsi tolleaegne õuekunstnik Jacob Heinrich Elbfas või tema töökoda. Rootsi kuninga Karl XI noorpõlveportreest (1670). Autor: Karl XI õuekunstnik David Klöcker Ehrenstrahl (1628-1698)
Ehasalu, Pia, 1964-
2004-01-01
Kuninganna Kristiina portreest lapsena (1638). Arvatav autor: Rootsi tolleaegne õuekunstnik Jacob Heinrich Elbfas või tema töökoda. Rootsi kuninga Karl XI noorpõlveportreest (1670). Autor: Karl XI õuekunstnik David Klöcker Ehrenstrahl (1628-1698)
The stable problem of the black-hole connected region in the Schwarzschild black hole
Tian, Guihua
2005-01-01
The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...
Institute of Scientific and Technical Information of China (English)
DING Chi-Kun; JING Ji-Liang
2007-01-01
@@ The statistical-mechanical entropies of the Schwarzschild black hole arising from the scalar, Weyl neutrino, electromagnetic, Rarita-Schwinger and gravitational fields are investigated in the Painlevé and Lernaitre coordinates.Although the metrics in the Painlevé and the Lemaitre coordinates do not obviously possess the singularity as that in the Schwarzschild coordinate, we find that the entropies of the arbitrary spin fields in both the Painlevé and Lemaitre coordinates are exactly equivalent to that in the Schwarzschild coordinate.
The stable problem of the black-hole connected region in the Schwarzschild black hole
Tian, Guihua
2005-01-01
The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...
Entropy of the Schwarzschild Black Hole in the Painlevé and the Lemaitre Coordinates
Institute of Scientific and Technical Information of China (English)
JING Ji-Liang; CHEN Song-Bai
2004-01-01
@@ In the Painlevé and the Lemaitre coordinates, the statistical-mechanical entropies of the Schwarzschild black hole arising from the quantum scalar field are investigated by using the 't Hooft's brick wall model At first sight,it seems that the results would be different from that in the standard Schwarzschild coordinate since both the Painlevé and the Lemaitre spacetimes do not possess the event horizon obviously. However, we prove that the entropies in these coordinates are exactly equivalent to that in the Schwarzschild coordinate.
[Karl Jaspers and the challenges of social psychiatry].
Jäger, Markus; Lang, Fabian U; Becker, Thomas
2015-01-01
Karl Jaspers, in his book "General Psychopathology", argued for methodological pluralism rather than theoretical dogmatism. He formulated a methodological order of psychopathology with a distinction between "explanation" (objective psychopathology) and "understanding" (subjective psychopathology, psychopathology of meaning). The latter approach focused on patients' subjective experience and biographical issues. Karl Jaspers emphasised social factors in the genesis and course of mental disorders. Following a multiperspective concept, from Jaspers' viewpoint social psychiatry should consider itself of equal importance with biological and psychotherapeutic psychiatry. Therefore, uncritical generalization of one of these perspectives should be avoided. Personalized psychiatry, apart from searching biological markers to tailor treatment should identify psychosocial factors and subjective meaning. Concepts of recovery should not ignore biological foundations in mental disorders.
Karl Raimund Popper: Problem Neopositivistik dan Teori Kritis Falsifikasi
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M. Syamsul Huda
2014-01-01
Full Text Available Karl Popper once criticizes the positivistic paradigm by means of what he calls the theory of falsification. To him, the positivistic paradigm constitutes a failure simply because it cannot distinguish between science and prude science, that is, between empirical method and non-empirical method. In the scientific knowledge, empirical science, mathematics and logic must be differentiated, something that the positivistic paradigm has failed to do. This paradigm furthermore, did not have a clear picture what logic-based science is, empirical knowledge and psychology of knowledge. It also fails to properly understand knowledge that springs from tradition, emotion, authority and so forth. All positivistic paradigms such as that of Karl Max’s Historicism, Freud’s theory of Psycho Analysis, Adler’s theory of Individual Analysis and Newton’s theory of Gravitation fall into this trap of failure.
Architecture and Art Regulations for Karl Marx Street
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Alla Mironenko
2015-08-01
Full Text Available The architecture and art regulations for Karl Marx Street and adjoining territories have been worked out for the Committee for town planning of the Irkutsk city administration. Basic provisions: facades of buildings and structures, outdoor advertising and information facilities, artistic illumination of buildings, elements of land improvements. The main principle is to preserve historical appearance and to create a contemporary and comfortable environment.
Transformation optics that mimics the system outside a Schwarzschild black hole
Chen, Huanyang; Miao, Rong-Xin; Li, Miao
2009-01-01
We applied the transformation optics to mimic a black hole of Schwarzschild form. Similar properties of photon sphere were also found numerically for the metamaterial black hole. Several reduced versions of the black hole systems were proposed for easier implementations.
Acceleration of particles to high energy via gravitational repulsion in the Schwarzschild field
McGruder, Charles H.
2017-01-01
Gravitational repulsion is an inherent aspect of the Schwarzschild solution of the Einstein-Hilbert field equations of general relativity. We show that this circumstance means that it is possible to gravitationally accelerate particles to the highest cosmic ray energies.
Black Hole Entropy Calculated via Wavefunction Approximations on a Schwarzschild Spacetime
2015-05-18
A TRIDENT SCHOLAR PROJECT REPORT NO. 443 Black Hole Entropy Calculated via Wavefunction Approximations on a Schwarzschild Spacetime...no. 443 (2015) Black Hole Entropy Calculated via Wavefunction Approximations on a Schwarzschild Spacetime by Midshipman 1/C Eric A...REPORT DATE (DD-MM-YYYY) 05-18-2015 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Black Hole Entropy Calculated via
K. Schwarzschild's problem in radiation transfer theory
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Rutily, B. [Centre de Recherche Astronomique de Lyon (UMR 5574 du CNRS), Observatoire de Lyon, 9 avenue Charles Andre, 69561 Saint-Genis-Laval Cedex (France)]. E-mail: rutily@obs.univ-lyon1.fr; Chevallier, L. [Centre de Recherche Astronomique de Lyon (UMR 5574 du CNRS), Observatoire de Lyon, 9 avenue Charles Andre, 69561 Saint-Genis-Laval Cedex (France); Pelkowski, J. [Institut fuer Meteorologie und Geophysik, J.W. Goethe Universitaet Frankfurt, Robert Mayer Strasse 1, D-60325 Frankfurt (Germany)
2006-03-15
We solve exactly the problem of a finite slab receiving an isotropic radiation on one side and no radiation on the other side. This problem-to be more precise the calculation of the source function within the slab-was first formulated by K. Schwarzschild in 1914. We first solve it for unspecified albedos and optical thicknesses of the atmosphere, in particular for an albedo very close to 1 and a very large optical thickness in view of some astrophysical applications. Then we focus on the conservative case (albedo=1), which is of great interest for the modeling of grey atmospheres in radiative equilibrium. Ten-figure tables of the conservative source function are given. From the analytical expression of this function, we deduce (1) a simple relation between the effective temperature of a grey atmosphere in radiative equilibrium and the temperature of the black body that irradiates it (2) the temperature at any point of the atmosphere when it is in local thermodynamical equilibrium. This temperature distribution is the counterpart, for a finite slab, of Hopf's distribution in a half-space. Its graphical representation is given for various optical thicknesses of the atmosphere.
Intrinsic Size OF Sgr A* 72 Schwarzschild Radii
Lo, K Y; Zhao, J H; Ho, P T P
1998-01-01
Recent proper motion studies of stars at the very center of the Galaxy strongly suggest that Sagittarius (Sgr) A*, the compact nonthermal radio source at the Galactic Center, is a 2.5 million solar mass black hole. By means of near-simultaneous multi-wavelength Very Long Baseline Array measurements, we determine for the first time the intrinsic size and shape of Sgr A* to be 72 Rsc by < 20 Rsc, with the major axis oriented essentially north-south, where Rsc (= 7.5 x 10^{11} cm) is the Schwarzschild radius for a 2.5 million solar mass black hole. Contrary to previous expectation that the intrinsic structure of Sgr A* is observable only at wavelengths shorter than 1 mm, we can discern the intrinsic source size at 7 mm because (1) the scattering size along the minor axis is half that along the major axis, and (2) the near simultaneous multi-wavelength mapping of Sgr A* with the same interferometer makes it possible to extrapolate precisely the minor axis scattering angle at 7 mm. The intrinsic size and shape ...
A Dynamical Systems Approach to Schwarzschild Null Geodesics
Belbruno, Edward
2011-01-01
The null geodesics of a Schwarzschild black hole are studied from a dynamical systems perspective. Written in terms of Kerr-Schild coordinates, the null geodesic equation takes on the simple form of a particle moving under the influence of a Newtonian central force with an inverse-cubic potential. We apply a McGehee transformation to these equations, which clearly elucidates the full phase space of solutions. All the null geodesics belong to one of four families of invariant manifolds and their limiting cases, further characterized by the angular momentum L of the orbit: for |L|>|L_c|, (1) the set that flow outward from the white hole, turn around, then fall into the black hole, (2) the set that fall inward from past null infinity, turn around outside the black hole to continue to future null infinity, and for |L|<|L_c|, (3) the set that flow outward from the white hole and continue to future null infinity, (4) the set that flow inward from past null infinity and into the black hole. The critical angular m...
Spectroscopy of the Schwarzschild black hole at arbitrary frequencies.
Casals, Marc; Ottewill, Adrian
2012-09-14
Linear field perturbations of a black hole are described by the Green function of the wave equation that they obey. After Fourier decomposing the Green function, its two natural contributions are given by poles (quasinormal modes) and a largely unexplored branch cut in the complex frequency plane. We present new analytic methods for calculating the branch cut on a Schwarzschild black hole for arbitrary values of the frequency. The branch cut yields a power-law tail decay for late times in the response of a black hole to an initial perturbation. We determine explicitly the first three orders in the power-law and show that the branch cut also yields a new logarithmic behavior T(-2ℓ-5)lnT for late times. Before the tail sets in, the quasinormal modes dominate the black hole response. For electromagnetic perturbations, the quasinormal mode frequencies approach the branch cut at large overtone index n. We determine these frequencies up to n(-5/2) and, formally, to arbitrary order. Highly damped quasinormal modes are of particular interest in that they have been linked to quantum properties of black holes.
Properties of standing Kruskal-Schwarzschild-modes at the magnetopause
Directory of Open Access Journals (Sweden)
F. Plaschke
2011-10-01
Full Text Available The radial, oscillatory motion of the Earth's magnetopause has been found to occur predominantly with some distinct, sometimes called "magic" frequencies, which have been attributed to magnetospheric wave guide modes, typical solar wind variations or, more recently, surface waves on the magnetopause standing between the northern and southern ionospheres. In this paper we present for the first time a derivation of these surface waves, denominated as Kruskal-Schwarzschild-modes (KS-modes, in the approximation of the ideal, single-fluid magnetohydrodynamic theory for incompressible plasmas. The calculations are performed in the simplified geometry of the box magnetosphere with the magnetopause being a plane between two plasma regimes of homogeneous conditions. The reflection of the KS-modes at the ionospheres is being discussed. Under the given assumptions and realistic conditions the validity of the calculations is shown to be limited to cases of parallel or anti-parallel background magnetic fields on both sides of the magnetopause, respectively. For these cases a detailed discussion of the mode structure is presented. The magnetopause when affected by a KS-mode is found to resemble a membrane under tension with respect to its motion; the ionospheres act as supporting points of the membrane and the KS-modes correspond in this picture to their eigenmodes of oscillation. Localized pressure enhancements in the magnetosheath are discussed as possible excitation mechanism for the KS-modes.
Resolving the Schwarzschild singularity in both classic and quantum gravity
Directory of Open Access Journals (Sweden)
Ding-fang Zeng
2017-04-01
Full Text Available The Schwarzschild singularity's resolution has key values in cracking the key mysteries related with black holes, the origin of their horizon entropy and the information missing puzzle involved in their evaporations. We provide in this work the general dynamic inner metric of collapsing stars with horizons and with non-trivial radial mass distributions. We find that static central singularities are not the final state of the system. Instead, the final state of the system is a periodically zero-cross breathing ball. Through 3+1 decomposed general relativity and its quantum formulation, we establish a functional Schrödinger equation controlling the micro-state of this breathing ball and show that, the system configuration with all the matter concentrating on the central point is not the unique eigen-energy-density solution. Using a Bohr–Sommerfield like “orbital” quantisation assumption, we show that for each black hole of horizon radius rh, there are about erh2/ℓpl2 allowable eigen-energy-density profiles. This naturally leads to physic interpretations for the micro-origin of horizon entropy, as well as solutions to the information missing puzzle involved in Hawking radiations.
A unified treatment of tidal disruption by Schwarzschild black holes
Servin, Juan
2016-01-01
Stars on orbits with pericenters sufficiently close to the supermassive black hole at the center of their host galaxy can be ripped apart by tidal stresses. Some of the resulting stellar debris becomes more tightly bound to the hole and can potentially produce an observable flare called a tidal-disruption event (TDE). We provide a self-consistent, unified treatment of TDEs by non-spinning (Schwarzschild) black holes, investigating several effects of general relativity including changes to the boundary in phase space that defines the loss-cone orbits on which stars are tidally disrupted or captured. TDE rates decrease rapidly at large black-hole masses due to direct stellar capture, but this effect is slightly countered by the widening of the loss cone due to the stronger tidal fields in general relativity. We provide a new mapping procedure that translates between Newtonian gravity and general relativity, allowing us to better compare predictions in both gravitational theories. Partial tidal disruptions in re...
Wave Propagation and Quasinormal Mode Excitation on Schwarzschild Spacetime
Dolan, Sam R
2011-01-01
To seek a deeper understanding of wave propagation on the Schwarzschild spacetime, we investigate the relationship between (i) the lightcone of an event and its caustics (self-intersections), (ii) the large-$l$ asymptotics of quasinormal (QN) modes, and (iii) the singular structure of the retarded Green function (GF) for the scalar field. First, we recall that the GF has a (partial) representation as a sum over QN modes. Next, we extend a recently-developed expansion method to obtain asymptotic expressions for QN wavefunctions and their residues. We employ these asymptotics to show (approximately) that the QN mode sum is singular on the lightcone, and to obtain approximations for the GF which are valid close to the lightcone. These approximations confirm a little-known prediction: the singular part of the GF undergoes a transition each time the lightcone passes through a caustic, following a repeating four-fold sequence. We conclude with a discussion of implications and extensions of this work.
Bose-Einstein graviton condensate in a Schwarzschild black hole
Alfaro, Jorge; Gabbanelli, Luciano
2016-01-01
We analyze in detail a previous proposal by Dvali and G\\'omez that black holes could be treated as consisting of a Bose-Einstein condensate of gravitons. In order to do so we extend the Einstein-Hilbert action with a chemical potential-like term, thus placing ourselves in a grand-canonical ensemble. The form and characteristics of this chemical potential-like piece are discussed in some detail. After this, we proceed to expand the ensuing equations of motion up to second order around the classical Schwarzschild metric so that some non-linear terms in the metric fluctuation are kept. We argue that the resulting equations could be interpreted as the Gross-Pitaevskii equation describing a graviton Bose-Einstein condensate trapped by the black hole gravitational field. Next we search for solutions and, modulo some very plausible assumptions, we find out that the condensate vanishes outside the horizon but is non-zero in its interior. Based on hints from a numerical integration of the equations we formulate an ans...
Spectroscopy of the Schwarzschild Black Hole at Arbitrary Frequencies
Casals, Marc
2012-01-01
Linear field perturbations of a black hole are described by the Green function of the wave equation that they obey. After Fourier decomposing the Green function, its two natural contributions are given by poles (quasinormal modes) and a largely unexplored branch cut in the complex-frequency plane. We present new analytic methods for calculating the branch cut on a Schwarzschild black hole for {\\it arbitrary} values of the frequency. The branch cut yields a power-law tail decay for late times in the response of a black hole to an initial perturbation. We determine explicitly the first three orders in the power-law and show that the branch cut also yields a new logarithmic behaviour for late times. Before the tail sets in, the quasinormal modes dominate the black hole response. For electromagnetic perturbations, the quasinormal mode frequencies approach the branch cut at large overtone index $n$. We determine these frequencies up to $n^{-5/2}$ and, formally, to {\\it arbitrary} order. Highly-damped quasinormal m...
Post-Newtonian Circular Restricted 3-Body Problem: Schwarzschild primaries
Dubeibe, F L; González, Guillermo A
2016-01-01
We study the dynamics of the planar circular restricted three body problem in the context of post-Newtonian approximations. First of all, we review the results obtained from the post-Newtonian equations of motion calculated in the framework of the Einstein-Infeld-Hoffmann formalism (EIH), where we show that, for arbitrary parameters, the Jacobian integral is not a conserved quantity. Therefore, using the Fodor-Hoenselers-Perjes formalism (FHP), we perform an expansion of the gravitational potential for two Schwarzschild black holes, deriving a new system of equations of motion, which preserve the Jacobian constant. The dynamics of this system is studied in terms of the Poincar\\'e section method and the Lyapunov exponents, where the introduction of a new parameter $\\epsilon$ allows us to observe the transition from the Newtonian to the post-Newtonian regime. Here we show that, when the initial conditions remain fixed, a Newtonian bounded orbit becomes unbounded in the post-Newtonian regime. Moreover, when the ...
Resolving the Schwarzschild singularity in both classic and quantum gravity
Zeng, Ding-fang
2017-04-01
The Schwarzschild singularity's resolution has key values in cracking the key mysteries related with black holes, the origin of their horizon entropy and the information missing puzzle involved in their evaporations. We provide in this work the general dynamic inner metric of collapsing stars with horizons and with non-trivial radial mass distributions. We find that static central singularities are not the final state of the system. Instead, the final state of the system is a periodically zero-cross breathing ball. Through 3+1 decomposed general relativity and its quantum formulation, we establish a functional Schrödinger equation controlling the micro-state of this breathing ball and show that, the system configuration with all the matter concentrating on the central point is not the unique eigen-energy-density solution. Using a Bohr-Sommerfield like ;orbital; quantisation assumption, we show that for each black hole of horizon radius rh, there are about e rh2/#x2113;pl 2 allowable eigen-energy-density profiles. This naturally leads to physic interpretations for the micro-origin of horizon entropy, as well as solutions to the information missing puzzle involved in Hawking radiations.
El racionalismo crítico de Karl Popper
Directory of Open Access Journals (Sweden)
Luis María Delio Machado
2015-10-01
Full Text Available El presente artículo, pretende acercar algunos de los aspectos más importantes del pensamiento de uno de los filósofos más destacados de nuestro tiempo: Sir Karl Popper. Su presencia atraviesa nuestro siglo, presentándose como una de las voces visionarias y anticipadoras que se alzaron críticamente, contra toda actitud o acción que estuviese fundada en lo dogmático y que tuviese como finalidad, el olvido o la superación del individuo, aunque dicho olvido estuviese "justificado" por oraculares "bienes o fines superiores". (...
Karl Nagel : Pain things = Pain things / Eha Komissarov
Komissarov, Eha, 1947-
2007-01-01
Maali- ja videokunstnik Karl Nagelist kui probleemsest nüüdisaegsest kunstnikust, kes võtab provokatiivseid positsioone ideoloogiate ja poliitika küsimustes. Tema kunstnikupositsioon keerleb terrorismi, fašismi ja natsionalismi ümber, dissidendi positsioonile asununa on ta käsitlenud surma ja vägivalla teemat (Tšetšeenia sõda) ja üritanud sõna võtta ka kodanikuvabaduste laiendamise nimel. Sotsiaalse tegelikkuse ja kunsti vastandlikkuse küsimuses on ta võtnud nulltoleratsi taotleva seisukoha, võrdlemata kunsti tegelikkusega
Karl Nagel : Pain things = Pain things / Eha Komissarov
Komissarov, Eha, 1947-
2007-01-01
Maali- ja videokunstnik Karl Nagelist kui probleemsest nüüdisaegsest kunstnikust, kes võtab provokatiivseid positsioone ideoloogiate ja poliitika küsimustes. Tema kunstnikupositsioon keerleb terrorismi, fašismi ja natsionalismi ümber, dissidendi positsioonile asununa on ta käsitlenud surma ja vägivalla teemat (Tšetšeenia sõda) ja üritanud sõna võtta ka kodanikuvabaduste laiendamise nimel. Sotsiaalse tegelikkuse ja kunsti vastandlikkuse küsimuses on ta võtnud nulltoleratsi taotleva seisukoha, võrdlemata kunsti tegelikkusega
Karl pearson the scientific life in a statistical age
Porter, Theodore M
2010-01-01
Karl Pearson, founder of modern statistics, came to this field by way of passionate early studies of philosophy and cultural history as well as ether physics and graphical geometry. His faith in science grew out of a deeply moral quest, reflected also in his socialism and his efforts to find a new basis for relations between men and women. This biography recounts Pearson's extraordinary intellectual adventure and sheds new light on the inner life of science. Theodore Porter's intensely personal portrait of Pearson extends from religious crisis and sexual tensions to metaphysical and even m
Reaction rates between water and the Karl Fischer reagent.
Cedergren, A
1974-04-01
Reaction rates between water and the Karl Fischer reagent have been determined by potentiometric measurement for various compositions of the Karl Fischer reagent. The study has been made with an iodine complex concentration of 0.3-1.2 mM and sulphur dioxide complex at 0.01-0.5M. The concentration of excess of pyridine had no measurable effect on the rate of the main reaction. The reaction was found to be first-order with respect to iodine complex, to sulphur dioxide complex, and to water. The rate constant was (1.2+/-0.2) x 10(3) 1(2). mole(-2). sec(-1). In an ordinary titration it is therefore essential to keep the sulphur dioxide concentration high for the reaction to go to completion within a reasonable time. The extent of side-reactions was found to be independent of the iodine concentration at low concentrations. The side-reactions increased somewhat with increasing sulphur dioxide pyridine concentrations and decreased to about 60% when the temperature was lowered from 24 degrees to 7 degrees.
Karl Barth’s epistemology: A critical appraisal
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Daniël P. Veldsman
2007-05-01
Full Text Available Can the great 20th century systematic theologian Karl Barth justify the fundamental beliefs he holds regarding the priority of God’s revelation in Jesus Christ as put forward in his impressive and comprehensive Kirchliche Dogmatik? Is it enough and thus theologically justifiable to simply state in the words of Barth that the best theology would need no advocates: it would prove itself? In my appraisal of Barth’s epistemological stance, I would like to argue in this article that his stance in the first place, does not only lead to a total isolation of theological reflection, but secondly through his highly exclusive claim, takes on the character of a personal religious credo expanded into a comprehensive doctrine beyond any form of control, and ultimately thirdly, becomes methodologically in essence a specifically Barthian theology from below. Wenn die Theologie sich eine Wissenschaft nennen lässt oder selber nennt, so kann sie damit keinerlei Verpflictung übernehmen, sich an den für andere Wissenschaften gültigen Massstäbem messen zu lassen. (Karl Barth 1947:8
German Astronomer Karl Menten Is 2007 Jansky Awardee
2007-06-01
Associated Universities, Inc., (AUI) and the National Radio Astronomy Observatory (NRAO) have awarded the 2007 Karl G. Jansky Lectureship to Professor Karl M. Menten of the Max-Planck-Institute for Radioastronomy in Bonn, Germany. The Jansky Lectureship is an honor established by the trustees of AUI to recognize outstanding contributions to the advancement of astronomy. Karl M. Menten Professor Karl M. Menten CREDIT: NRAO/AUI Click on image for high-resolution file (433 KB) Professor Menten is an extraordinarily productive scientist whose research has improved our fundamental understanding in a number of areas of astronomy. He has studied the chemistry of molecular clouds from which new stars are formed, the process of star formation in our own Milky Way Galaxy and in the early Universe, and the outer atmospheres of stars nearing the end of their "normal" lives. In 1991, Menten used NRAO's 140-foot Telescope at Green Bank, West Virginia, to discover strong radio emission from methanol masers in star-forming regions. These masers amplify, or strengthen, radio emission the same way a laser amplifies visible-light emission. Menten developed the observation of these methanol masers into a powerful tool for studying the formation of stars much more massive than our Sun, because the strong maser emission points astronomers to the stellar birthplaces. In addition, Menten pioneered the use of ultra-high-resolution observations with NRAO's Very Long Baseline Array to observe masers to make precision determinations of the structure, size and dynamics of the Milky Way. Menten received his doctoral degree in 1987 from the University of Bonn, Germany. He then joined the Harvard-Smithsonian Center for Astrophysics, working there until 1996, when he became the Director for Millimeter and Submillimeter Astronomy at the Max-Planck-Institute for Radioastronomy. In addition to that position, he also has been a Professor for Experimental Astrophysics at the University of Bonn since
Martínez-Morales, José L.
The master equations in the Euclidean Schwarzschild-Tangherlini space-time of a small static perturbation are studied. For each harmonic mode on the sphere there are two solutions that behave differently at infinity. One solution goes like the power 2-l-n of the radial variable, the other solution goes like the power l. These solutions occur in power series. The second main statement of the paper is that any eigentensor of the Lichnerowicz operator in a Euclidean Schwarzschild space-time with an eigenvalue different from zero is essentially singular at infinity. Possible applications of the stability of instantons are discussed. We present the analysis of a small static perturbation of the Euclidean Schwarzschild-Tangherlini metric tensor. The higher order perturbations will appear later. We determine independently the static perturbations of the Schwarzschild quantum black hole in dimension 1+n≥4, where the system of equations is reduced to master equations — ordinary differential equations. The solutions are hypergeometric functions which in some cases can be reduced to polynomials. In the same Schwarzschild background, we analyze static perturbations of the scalar mode and show that there does not exist any static perturbation that is regular everywhere outside the event horizon and is well-behaved at the spatial infinity. This confirms the uniqueness of the spherically symmetric static empty quantum black hole, within the perturbation framework. Our strategy for treating the stability problem is also applicable to other symmetric quantum black holes with a nonzero cosmological constant.
Features and stability analysis of non-Schwarzschild black hole in quadratic gravity
Cai, Yi-Fu; Liu, Junyu; Zhang, Hezi
2016-01-01
Black holes are found to exist in gravitational theories with the presence of quadratic curvature terms and behave differently from the Schwarzschild solution. We present an exhaustive analysis for determining the quasinormal modes of a test scalar field propagating in a new class of black hole backgrounds in the case of pure Einstein-Weyl gravity. Our result shows that the field decay of quasinormal modes in such a non-Schwarzschild black hole behaves similarly to the Schwarzschild one, but the decay slope becomes much smoother due to the appearance of the Weyl tensor square in the background theory. We also analyze the frequencies of the quasinormal modes in order to characterize the properties of new back holes, and thus, if these modes can be the source of gravitational waves, the underlying theories may be testable in future gravitational wave experiments. We briefly comment on the issue of quantum (in)stability in this theory at linear order.
Stability of Schwarzschild-AdS for the spherically symmetric Einstein-Klein-Gordon system
Holzegel, Gustav
2011-01-01
In this paper, we study the global behavior of solutions to the spherically symmetric coupled Einstein-Klein-Gordon (EKG) system in the presence of a negative cosmological constant. We prove that the Schwarzschild-AdS spacetimes (the trivial black hole solutions of the EKG system for which $\\phi=0$ identically) are asymptotically stable: Small perturbations of Schwarzschild-AdS initial data again lead to regular black holes, with the metric on the black hole exterior approaching a Schwarzschild-AdS spacetime. The main difficulties in the proof arise from the lack of monotonicity for the Hawking mass and the asymptotically AdS boundary conditions, which render even (part of) the orbital stability intricate. These issues are resolved in a bootstrap argument on the black hole exterior, with the redshift effect and weighted Hardy inequalities playing the fundamental role in the analysis. Both integrated decay and pointwise decay estimates are obtained.
Sarkar, Tamal; Bhadra, Arunava
2014-01-01
The late time accelerated expansion of the Universe demands that even in local galactic-scales it is desirable to study astrophysical phenomena, particularly relativistic accretion related phenomena in massive galaxies or in galaxy mergers and the dynamics of the kiloparsecs-scale structure and beyond, in the local-galaxies in Schwarzschild-de Sitter (SDS) background, rather than in Schwarzschild or Newtonian paradigm. Owing to the complex and nonlinear character of the underlying magnetohydrodynamical equations in general relativistic (GR) regime, it is quite useful to have an Newtonian analogous potential containing all the important GR features that allows to treat the problem in Newtonian framework for study of accretion and its related processes. From the principle of conserved Hamiltonian of the test particle motion, here, a three dimensional Newtonian analogous potential has been obtained in spherical geometry corresponding to SDS/Schwarzschild anti-de Sitter (SADS) spacetime, that reproduces almost al...
Hackmann, Eva
2015-01-01
The complete set of analytic solutions of the geodesic equation in a Schwarzschild--(anti-)de Sitter space--time is presented. The solutions are derived from the Jacobi inversion problem restricted to the set of zeros of the theta function, called the theta divisor. In its final form the solutions can be expressed in terms of derivatives of Kleinian sigma functions. The different types of the resulting orbits are characterized in terms of the conserved energy and angular momentum as well as the cosmological constant. Using the analytical solution, the question whether the cosmological constant could be a cause of the Pioneer Anomaly is addressed. The periastron shift and its post--Schwarzschild limit is derived. The developed method can also be applied to the geodesic equation in higher dimensional Schwarzschild space--times.
Features and stability analysis of non-Schwarzschild black hole in quadratic gravity
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Cai, Yi-Fu [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy,University of Science and Technology of China, Chinese Academy of Sciences,Hefei, Anhui, 230026 (China); Department of Physics, McGill University,Montréal, Quebec, H3A 2T8 (Canada); School of Physical Sciences, University of Science and Technology of China,Hefei, Anhui, 230026 (China); Zhang, Hezi [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy,University of Science and Technology of China, Chinese Academy of Sciences,Hefei, Anhui, 230026 (China); School of Physical Sciences, University of Science and Technology of China,Hefei, Anhui, 230026 (China); Liu, Junyu [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy,University of Science and Technology of China, Chinese Academy of Sciences,Hefei, Anhui, 230026 (China); School of the Gifted Young, University of Science and Technology of China,Hefei, Anhui, 230026 (China); Cheng, Gong [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy,University of Science and Technology of China, Chinese Academy of Sciences,Hefei, Anhui, 230026 (China); School of Physical Sciences, University of Science and Technology of China,Hefei, Anhui, 230026 (China); Wang, Min [Faculty of Materials and Energy, Southwest University,Chongqing, 400715 (China); CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy,University of Science and Technology of China, Chinese Academy of Sciences,Hefei, Anhui, 230026 (China)
2016-01-19
Black holes are found to exist in gravitational theories with the presence of quadratic curvature terms and behave differently from the Schwarzschild solution. We present an exhaustive analysis for determining the quasinormal modes of a test scalar field propagating in a new class of black hole backgrounds in the case of pure Einstein-Weyl gravity. Our result shows that the field decay of quasinormal modes in such a non-Schwarzschild black hole behaves similarly to the Schwarzschild one, but the decay slope becomes much smoother due to the appearance of the Weyl tensor square in the background theory. We also analyze the frequencies of the quasinormal modes in order to characterize the properties of new back holes, and thus, if these modes can be the source of gravitational waves, the underlying theories may be testable in future gravitational wave experiments. We briefly comment on the issue of quantum (in)stability in this theory at linear order.
Conservation laws and flux bounds for gravitational perturbations of the Schwarzschild metric
Holzegel, Gustav
2016-01-01
We derive an energy conservation law for the system of gravitational perturbations on the Schwarzschild spacetime expressed in a double null gauge. The resulting identity involves only first derivatives of the metric perturbation. Exploiting the gauge invariance up to boundary terms of the fluxes that appear, we are able to establish positivity of the flux on any outgoing null hypersurface to the future of the initial data. This allows us to bound the total energy flux through any such hypersurface, including the event horizon, in terms of initial data. We similarly bound the total energy radiated to null infinity. Our estimates provide a direct approach to a weak form of stability, thereby complementing the proof of the full linear stability of the Schwarzschild solution recently obtained in [M. Dafermos, G. Holzegel and I. Rodnianski \\emph{The linear stability of the Schwarzschild solution to gravitational perturbations}, arXiv:1601.06467].
Conservation laws and flux bounds for gravitational perturbations of the Schwarzschild metric
Holzegel, Gustav
2016-10-01
We derive an energy conservation law for the system of gravitational perturbations on the Schwarzschild spacetime expressed in a double null gauge. The resulting identity involves only first derivatives of the metric perturbation. Exploiting the gauge invariance up to boundary terms of the fluxes that appear, we are able to establish positivity of the flux on any outgoing null hypersurface to the future of the initial data. This allows us to bound the total energy flux through any such hypersurface, including the event horizon, in terms of initial data. We similarly bound the total energy radiated to null infinity. Our estimates provide a direct approach to a weak form of stability, thereby complementing the proof of the full linear stability of the Schwarzschild solution recently obtained in Dafermos et al (2016 The linear stability of the Schwarzschild solution to gravitational perturbations arXiv:1601.06467).
Rain, Hail, and Drip frames of the Schwarzschild-de Sitter Geometry
Finch, Tehani
2017-01-01
Various families of coordinate systems associated with observers moving inwardly along radial geodesics in the Schwarzschild geometry have been constructed by generalizing the Painleve-Gullstrand coordinates. Such observers have categorized as being in the rain frame, a hail frame, or a drip frame, by Taylor and Wheeler. This framework naturally progresses into a search for counterparts of these coordinate systems for the Schwarzschild-de Sitter (SdS) geometry. Consideration of local measurements made by a fiducial observer suggests that the conserved Killing quantity which best fits the designation of ``energy'' in the SdS geometry differs from the one which is typically denoted as such. This leads to Painleve-Gullstrand-style coordinate systems for the SdS geometry that differ from the naïve extrapolations of the Schwarzschild or de Sitter geometries.
Thermodynamics of the Schwarzschild and the Reissner–Nordström black holes with quintessence
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K. Ghaderi
2016-02-01
Full Text Available In this paper, we study the thermodynamics of the Schwarzschild and the Reissner–Nordström black holes surrounded by quintessence. By using the thermodynamical laws of the black holes, we derive the thermodynamic properties of these black holes and we compare the results with each other. We investigate the mass, temperature and heat capacity as functions of entropy for these black holes. We also discuss the equation of state of the Schwarzschild and the Reissner–Nordström black holes surrounded by quintessence.
Guendelman, Eduardo I; Granit, Gilad; Ygael, Tomer; Rohrhofer, Christian
2015-01-01
As it is well known, the $0-0$ component of the Schwarzschild space can be obtained by the requirement that the geodesic of slowly moving particles match the Newtonian equation. Given this result, we show here that the remaining components can be obtained by requiring that the inside of a Newtonian ball of dust matched at a free falling radius with the external space determines that space to be Schwarzschild, if no pathologies exist. Also we are able to determine that the constant of integration that appears in the Newtonian Cosmology coincides with the spacial curvature of the FLRW metric.
Scalar self-force on a static particle in Schwarzschild spacetime using the massive field approach
Rosenthal, Eran
2004-12-01
I use the recently developed massive field approach to calculate the scalar self-force on a static particle in a Schwarzschild spacetime. In this approach the scalar self-force is obtained from the difference between the (massless) scalar field, and an auxiliary massive scalar field combined with a certain limiting process. By applying this approach to a static particle in Schwarzschild I show that the scalar self-force vanishes in this case. This result conforms with a previous analysis [A. G. Wiseman, Phys. Rev. D612000084014].
Saleh, Mahamat; Bouetou, Bouetou Thomas; Kofane, Timoleon Crepin
2016-04-01
In this work, quasinormal modes (QNMs) of the Schwarzschild black hole are investigated by taking into account the quantum fluctuations. Gravitational and Dirac perturbations were considered for this case. The Regge-Wheeler gauge and the Dirac equation were used to derive the perturbation equations of the gravitational and Dirac fields respectively and the third order Wentzel-Kramers-Brillouin (WKB) approximation method is used for the computing of the quasinormal frequencies. The results show that due to the quantum fluctuations in the background of the Schwarzschild black hole, the QNMs of the black hole damp more slowly when increasing the quantum correction factor (a), and oscillate more slowly.
Saleh, Mahamat; Crépin, Kofané Timoléon
2016-01-01
In this work, quasinormal modes (QNMs) of the Schwarzschild black hole are investigated by taking into account the quantum fluctuations. Gravitational and Dirac perturbations were considered for this case. The Regge-Wheeler gauge and the Dirac equation were used to derive the perturbation equations of the gravitational and Dirac fields respectively and the third order Wentzel-Kramers-Brillouin (WKB) approximation method is used for the computing of the quasinormal frequencies. The results show that due to the quantum fluctuations in the background of the Schwarzschild black hole, the QNMs of the black hole damp more slowly when increasing the quantum correction factor (a), and oscillate more slowly.
Karl Polanyi og utopien om det fri marked
DEFF Research Database (Denmark)
Christiansen, Christian O.
2012-01-01
This article offers the first comprehensive introduction to Karl Polanyi’s The Great Transformation (TGT) from 1944 written in Danish. Relatively unnoticed by the time of its publication, TGT has since received widespread attention, especially after the rise of economic globalisation and of neo-l...... intellectual history, and its historical significance. The article introduces main themes of TGT and the reception of TGT. At the end, it briefly sketches a ‘Polanyian’ account of the world financial crisis of 2008.......-liberal policies. The thesis of TGT is that the great wars and crisis of Western civilization in the 20th century should be seen against the backdrop of the 19th century’s liberal civilisation. Polanyi argues that the attempt to create a liberal, free market world order was crucial for the later breakdown...
Descriptive psychopathology, phenomenology, and the legacy of Karl Jaspers.
Häfner, Heinz
2015-03-01
With his early publications (1910-1913), Karl Jaspers created a comprehensive methodological arsenal for psychiatry, thus laying the foundation for descriptive psychopathology. Following Edmund Husserl, the founder of philosophical phenomenology, Jaspers introduced phenomenology into psychopathology as "static understanding," ie, the unprejudiced intuitive reproduction (Vergegenwärtigung) and description of conscious phenomena. In a longitudinal perspective, "genetic understanding" based on empathy reveals how mental phenomena arise from mental phenomena. Severance in understanding of, or alienation from, meaningful connections is seen as indicating illness or transition of a natural development into a somatic process. Jaspers opted for philosophy early. After three terms of law, he switched to studying medicine, came to psychopathology after very little training in psychiatry; to psychology without ever studying psychology; and to a chair in philosophy without ever studying philosophy. In the fourth and subsequent editions of his General Psychopathology, imbued by his existential philosophy, Jaspers partly abandoned the descriptive method.
The origin of art according to Karl von den Steinen
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Pierre Déléage
2015-06-01
Full Text Available Based on a study of the custom, adopted by ethnologists in the early 20th century, of asking Amerindians of Lowland South America to do drawings in pencil in their notebooks, I explore three forgotten fragments of the history of thinking: the intense debates on the origin of ornaments, opposing an evolutionist and a materialist approach at the end of the 19th century; the theories on the origin of figuration, which I show date back to the important work of Karl von den Steinen regarding the populations of central Brazil; and the publications of ethnologists’ portraits drawn by Indians of the lowlands of South America, a little-known tradition of reverse anthropology serving as a counterpoint to the study of the reception of Amerindian art in Western ethnological literature.
Wie is die sondaar? Die beskouing van Karl Barth
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F. J. van Zyl
1994-01-01
Full Text Available Who is the sinner? The view of Karl Barth The previous article dealt with Barth’s view of the knowledge and real essence of sin, while this one focus on his view of the human being as sinner. In accordance with his christological approach to all theological matters, Barth presents us with a description of the image and character of the sinner as mirrored by the obedient suffering and death of Jesus Christ on the cross in the place of all sinners of all times - past, present and future. The price that God paid in surrendering his only Son to such suffering, indicates the enormous guilt and baseness of every sinner. Every human being is utterly insolvent and can only be delivered from sin through God’s graceful remission of siru
Sir Karl Popper and his philosophy of physics
Jammer, Max
1991-12-01
The eminent mathematical physicist Sir Hermann Bondi once said: “There is no more to science than its method, and there is no more to its method than Popper has said.” Indeed, many regard Sir Karl Raimund Popper the greatest philosopher of science in our generation. Much of what Popper “has said” refers to physics, but physicists, generally speaking, have little knowledge of what he has said. True, Popper's philosophy of science and, in particular, his realistic interpretation of quantum mechanics deviates considerably from the generally accepted doctrine. But as Popper, rightly I think, points out, it is precisely the proliferation of divergent theories which promotes the growth of scientific knowledge; it would be a danger for physics if physicists were dogmatically tied to a single theory or would not test their theory against alternatives. It is for this purpose that, on the occasion of the nonagenarian celebration of Popper's birthday, the present essay has been written.
Karl Heinz Göller (1924-2009: in memoriam
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Janez Stanonik
2010-12-01
Full Text Available The study is written in memory of Karl Heinz Göller, Professor of English literature at the Regensburg University, who died in Kelheim near Regensburg on 22nd April 2009. University of Regenburg was founded in 1967, and Göller was the first Dean of its Faculty of Philosophy. For more than 40 years he worked for the development of good contacts betwen the universities of Regensburg and Ljubljana. Since 2000 he was member of the Advisory Committee of the review Acta Neophilologica. In 1983 he founded the Society of German Mediaevalists, one of the leading societies of German scholars from the whole Germany, and was elected its first president. The study gives report on the development of Göller as a scholar, and his basic achievement in his research, pedagogical work and in university administration.
Institute of Scientific and Technical Information of China (English)
孙逸轩（编）; Holly（译）
2008-01-01
著名的Dom Perignon不久前邀请到时装大师Karl Lagerfeld为英国Harrods百货设计了一款Dom Perignon Rose Vintages限量礼盒装。并已在Harrods百货公司开始出售。这款Dom Perignon Rose Vintages限量礼盒外型很似订制吉他盒,粉色蛇纹外表搭配闪耀的金属扣,整体感觉前卫、时髦,盒内衬有同色羔羊皮,并装有六只珍藏的精巧Dom Perignon Rose Vintages与三个香槟杯。
Karl Popper: antes y después de Kyoto
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Zanotti, Gabriel
1999-06-01
Full Text Available Not available.En su último libro sobre Karl Popper, Mariano Artigas plantea una hermenéutica revolucionaria: muestra que la ética de Popper es el fundamento de su epistemología, y que el fundamento de esa ética está lejos del «conjeturalismo» que suele atribuirse a Popper. Artigas analiza qué significa en Popper la «fe irracional en la razón» y utiliza, como fuente inédita, el dramático relato que hace Popper de su relación con W. W. Bartley, por primera vez, en Kyoto, en 1992. Sea cual fuere la opinión del lector, el libro de Artigas divide la hermenéutica de Popper en un antes y un después.
Karl Heinrich Ulrichs: First Theorist of Erotic Age Orientation.
Janssen, Diederik F
2017-01-01
The nomination of Karl Heinrich Ulrichs (1825-1895) as the first theorist of homosexuality may be placed in the oblique light of his eligibility for the nomination as the first theorist of erotic age orientation. In Ulrichs's pamphlets, "man-manly" homosexuality emerged as a particular age orientation, with a subsequent typological breakdown that, importantly, blended gender orientation and age orientation. Into the early 20th century, erotic age orientation remained bound up with the classification and emancipation of what here was demarcated as Urningsliebe. Ulrichs's pioneering and shifting comments on age eventually fed into his legal model of consenting adults in private. They also provide a starting point for the historical understanding of the trope of "grooming pedophile" as it, arguably, crossfaded with that of the "seducing homosexual" after the latter's depsychiatricization across the Western world.
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Angelo Segrillo
Full Text Available Resumo O artigo analisa a visão de Karl Marx sobre a possibilidade de ocorrência da revolução na Rússia. Inicialmente concentrando suas esperanças nos países da Europa Ocidental, onde o capitalismo estava mais desenvolvido, com o fracasso das revoluções de 1948 e da Comuna de Paris, Marx se volta para as possibilidades de revolução a partir do Leste, da Rússia, até ali considerada o bastião da reação. Suas ideias são expostas em correspondência com os próprios revolucionários russos. Essa trajetória intelectual de Marx é descrita a partir de seus próprios escritos.
Karl Popper's Conception of Metaphysics and its Problems
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Cláudia Ribeiro
2014-08-01
Full Text Available In this paper I intend to thoroughly analyse Karl Popper’s relation to metaphysics. I start with his first writings, where he states the differences between science, pseudoscience and metaphysics. I then describe how his thoughts on the subject evolved to culminate in his reflection on metaphysical research programmes and the need for a revival of natural philosophy. A major concern is Popper’s famous testability criterion to set apart science from non-science. I point at the problems of the conception of metaphysics as non-testable theories (which are similar to the problems of the conception of metaphysics as theories involving unobservables and, in order to avoid these problems, I propose to retain nothing but the traditional conception of metaphysics as the general theories about the nature of the world. This leads me to the conclusion that science is not only an empirical task but also, and in a very important sense, a speculative one.
O marxismo antidogmático de Karl Korsch
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Nildo Viana
2013-06-01
Full Text Available O presente artigo tematiza o marxismo de Karl Korsch, focalizando seu caráter não dogmático. A partir de um resgate do caráter crítico e revolucionário do marxismo de Marx, Korsch realiza uma crítica radical ao revisionismo e leninismo. Para tal, ele não só resgata o verdadeiro caráter da dialética marxista e da concepção materialista da história, como exige a coerência dessa concepção ao defender o princípio de aplicação dela a si mesma. Assim ele lança as bases de um marxismo não dogmático, para o qual é o vínculo com o proletariado que mostra o caráter do marxismo e não ideologias petrificadas. Abstract: This article thematizes Marxism of Karl Korsch, focusing on its non dogmatic. From a rescue of criticality and revolutionary Marxism of Marx, Korsch performs a radical critique of revisionism and Leninism. To do so, he not only rescues the true character of Marxist dialectics and materialist conception of history, as this concept requires consistency in defending the principle of applying it to herself. So he lays the foundations of a non-dogmatic Marxism, to which is the bond with the proletariat that shows the character of Marxism and not petrified ideologies. Key words: Marxism, dogmatism, criticism, historical materialism, dialectical.
Institute of Scientific and Technical Information of China (English)
李固强
2006-01-01
运用Parikh模型,研究任意维Schwarzschild-de Sitter(SdS)黑洞的Hawking隧穿辐射.结果表明,黑洞视界处的隧穿率依赖于Bekenstein-Hawking(BH)熵的变化,如果考虑到熵的变化按出射粒子能量展开式中的高次项,辐射谱不再是纯热的谱.
Lee, Kuo-Wei
2016-01-01
We prove the existence and uniqueness of the Dirichlet problem for spacelike, spherically symmetric, constant mean curvature equation with symmetric boundary data in the extended Schwarzschild spacetime. As an application, we completely solve the CMC foliation conjecture which is posted by Malec and O Murchadha in 2003.
Lee, Kuo-Wei
2016-09-01
We prove the existence and uniqueness of the Dirichlet problem for the spacelike, spherically symmetric, constant mean curvature equation with symmetric boundary data in the extended Schwarzschild spacetime. As an application, we completely solve the CMC foliation conjecture which is proposed by Malec and Murchadha (2003 Phys. Rev. D 68 124019).
Augousti, A. T.; Gawelczyk, M.; Siwek, A.; Radosz, A.
2012-01-01
The problem of communication between observers in the vicinity of a black hole in a Schwarzschild metric is considered. The classic example of an infalling observer Alice and a static distant mother station (MS) is extended to include a second infalling observer Bob, who follows Alice in falling towards the event horizon. Kruskal coordinates are…
Brick Wall Model and the Spectrum of a Schwarzschild Black Hole
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LI Xiang; ZHAO Zheng
2006-01-01
@@ The quantum entropy of a scalar field near a Schwarzschild black hole is investigated by employing the brick-wall model in the grand canonical ensemble. A positive chemical potential is introduced if the cutoff is set to be of order of the Planck length. We also discuss the relation between the chemical potential and the mass quantum of the black hole.
Interactive Visualization of a Thin Disc around a Schwarzschild Black Hole
Muller, Thomas; Frauendiener, Jorg
2012-01-01
In a first course in general relativity, the Schwarzschild spacetime is the most discussed analytic solution to Einstein's field equations. Unfortunately, there is rarely enough time to study the optical consequences of the bending of light for some advanced examples. In this paper, we present how the visual appearance of a thin disc around a…
Interactive Visualization of a Thin Disc around a Schwarzschild Black Hole
Muller, Thomas; Frauendiener, Jorg
2012-01-01
In a first course in general relativity, the Schwarzschild spacetime is the most discussed analytic solution to Einstein's field equations. Unfortunately, there is rarely enough time to study the optical consequences of the bending of light for some advanced examples. In this paper, we present how the visual appearance of a thin disc around a…
Augousti, A. T.; Gawelczyk, M.; Siwek, A.; Radosz, A.
2012-01-01
The problem of communication between observers in the vicinity of a black hole in a Schwarzschild metric is considered. The classic example of an infalling observer Alice and a static distant mother station (MS) is extended to include a second infalling observer Bob, who follows Alice in falling towards the event horizon. Kruskal coordinates are…
On Schwarzschild black holes in a D-dimensional noncommutative space
Chabab, M; Sedra, M B
2012-01-01
This work aims to implement the idea of noncommutativity in the subject of black holes. Its principal contents deal with a study of Schwarzschild black holes in a D-dimensional noncommutative space. Various aspects related to the non commutative extension are discussed and some non trivial results are derived.
Seeing relativity -- I. Basics of a raytracing code in a Schwarzschild metric
Riazuelo, Alain
2015-01-01
We present here an implementation of a raytracing code in the Schwarzschild metric. We aim at building a numerical code with a correct implementation of both special (aberration, amplification, Doppler) and general (deflection of light, lensing, gravitational redshift) relativistic effects by paying attention to a good rendering of stars
The \\c{hi}2-test, the Muon AMM and Karl R. Popper
Iurato, Giuseppe
2013-01-01
In this very brief note, we only wish to identify a simple but notable epistemological basis, concerning the Karl R. Popper philosophy of science thought, into the realm of the experimental proves of Fundamental Physics.
Karl E. Mundt National Wildlife Refuge: Annual narrative report: Calendar year 1978
US Fish and Wildlife Service, Department of the Interior — This narrative report for Karl E. Mundt NWR outlines Refuge accomplishments during the 1978 calendar year. The report begins with an introduction to the Refuge and...
Karl E. Mundt National Wildlife Refuge: Annual narrative report: Calendar year 1979
US Fish and Wildlife Service, Department of the Interior — This narrative report for Karl E. Mundt NWR outlines Refuge accomplishments during the 1979 calendar year. The report begins with an introduction to the Refuge and...
Karl E. Mundt National Wildlife Refuge: Annual narrative report: Calendar year 1980
US Fish and Wildlife Service, Department of the Interior — This narrative report for Karl E. Mundt NWR outlines Refuge accomplishments during the 1980 calendar year. The report begins with an introduction to the Refuge and...
Testing the null hypothesis: the forgotten legacy of Karl Popper?
Wilkinson, Mick
2013-01-01
Testing of the null hypothesis is a fundamental aspect of the scientific method and has its basis in the falsification theory of Karl Popper. Null hypothesis testing makes use of deductive reasoning to ensure that the truth of conclusions is irrefutable. In contrast, attempting to demonstrate the new facts on the basis of testing the experimental or research hypothesis makes use of inductive reasoning and is prone to the problem of the Uniformity of Nature assumption described by David Hume in the eighteenth century. Despite this issue and the well documented solution provided by Popper's falsification theory, the majority of publications are still written such that they suggest the research hypothesis is being tested. This is contrary to accepted scientific convention and possibly highlights a poor understanding of the application of conventional significance-based data analysis approaches. Our work should remain driven by conjecture and attempted falsification such that it is always the null hypothesis that is tested. The write up of our studies should make it clear that we are indeed testing the null hypothesis and conforming to the established and accepted philosophical conventions of the scientific method.
Centenary of Karl Jaspers's general psychopathology: implications for molecular psychiatry.
Thome, Johannes
2014-01-01
Modern molecular psychiatry benefits immensely from the scientific and technological advances of general neuroscience (including genetics, epigenetics, and proteomics). This "progress" of molecular psychiatry, however, will be to a degree "unbalanced" and "epiphytic" should the development of the corresponding theoretical frameworks and conceptualization tools that allow contextualization of the individual neuroscientific findings within the specific perspective of mental health care issues be neglected. The General Psychopathology, published by Karl Jaspers in 1913, is considered a groundbreaking work in psychiatric literature, having established psychopathology as a space of critical methodological self-reflection, and delineating a scientific methodology specific to psychiatry. With the advance of neurobiology and molecular neuroscience and its adoption in psychiatric research, however, a growing alienation between current research-oriented neuropsychiatry and the classical psychopathological literature is evident. Further, consensus-based international classification criteria, although useful for providing an internationally accepted system of reliable psychiatric diagnostic categories, further contribute to a neglect of genuinely autonomous thought on psychopathology. Nevertheless, many of the unsolved theoretical problems of psychiatry, including those in the areas of nosology, anthropology, ethics, epistemology and methodology, might be fruitfully addressed by a re-examination of classic texts, such as Jaspers's General Psychopathology, and their further development and adaptation for 21st century psychiatry.
Falsifications and corroborations: Karl Popper's influence on systematics.
Helfenbein, Kevin G; DeSalle, Rob
2005-04-01
Over the last three decades, the philosophy of Karl Raimund Popper has had a strong influence on the field of systematic biology. Unequivocally, no other philosopher's work has had such an influence during this formative period in systematics. Much, but not all, of the early discourse on Popper and systematics dealt with the philosophical basis of systematics as a science. More recently Popper's work has been discussed in the systematics literature in relation to specific methodologies such as parsimony and maximum likelihood. In this paper, we provide the reader with a concise summary of Popper's ideas relevant to systematics, review the systematic literature invoking or declining Popper's importance to the field, and make a recommendation for the future course of philosophical thinking in systematics. We try to make clear various authors' interpretations of Popper's work and how those interpretations have impacted systematic thought. Although the reader may come away from this review with a clearer idea of Popper's relevance or lack thereof, our primary hope is that the reader will be compelled to question him- or herself about the philosophical basis of the systematic work that he or she does, and to delve into the literature herein cited. We begin by presenting a synopsis of Popper's philosophical views to allow those views to be placed in the context of systematics.
Karl Marx and the Study of Media and Culture Today
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Christian Fuchs
2014-02-01
Full Text Available The task of this paper discusses the role of Marx in analysing media, communica-tion and culture today. An analysis of three contemporary Cultural Studies works – Lawrence Grossberg’s monograph Cultural Studies in the Future Tense, John Hartley’s monograph Digital Futures for Cultural and Media Studies and Paul Smith’s edited volume The Renewal of Cultural Studies – shows that there is an agreement that the economy needs to be taken more into account by Cultural Studies, but disagreement on which approach should be taken and what the role of Karl Marx’s works shall be. The paper argues that Marx’s labour theory of value is especially important for critically analysing the media, culture and communica-tion. Labour is still a blind spot of the study of culture and the media, although this situation is slowly improving. It is maintained that the turn away from Marx in Cultural and Media Studies was a profound mistake that should be reverted. Only an engagement with Marx can make Cultural and Media Studies topical, politically relevant, practical and critical, in the current times of global crisis and resurgent critique.
Karl Pearson and eugenics: personal opinions and scientific rigor.
Delzell, Darcie A P; Poliak, Cathy D
2013-09-01
The influence of personal opinions and biases on scientific conclusions is a threat to the advancement of knowledge. Expertise and experience does not render one immune to this temptation. In this work, one of the founding fathers of statistics, Karl Pearson, is used as an illustration of how even the most talented among us can produce misleading results when inferences are made without caution or reference to potential bias and other analysis limitations. A study performed by Pearson on British Jewish schoolchildren is examined in light of ethical and professional statistical practice. The methodology used and inferences made by Pearson and his coauthor are sometimes questionable and offer insight into how Pearson's support of eugenics and his own British nationalism could have potentially influenced his often careless and far-fetched inferences. A short background into Pearson's work and beliefs is provided, along with an in-depth examination of the authors' overall experimental design and statistical practices. In addition, portions of the study regarding intelligence and tuberculosis are discussed in more detail, along with historical reactions to their work.
Teixeira, José A. Carvalho
2014-01-01
Publicam-se agora as Actas do Colóquio 100 ANOS DA ‘PSICOPATOLOGIA GERAL’ DE KARL JASPERS, realizado em 19 de Fevereiro de 2014 e organizado pelo Departamento de Psicologia Clínica e da Saúde do ISPA – Instituto Universitário.
How Slice Stretching arises when Maximally Slicing the Schwarzschild Spacetime with Vanishing Shift
Reimann, B
2004-01-01
When foliating the extended Schwarzschild spacetime with maximal slices while using zero shift, slice stretching effects such as slice sucking and slice wrapping arise. These effects are due to the differential infall of Eulerian observers and can be quantified for arbitrary spatial coordinates in the context of even boundary conditions. As examples logarithmic and isotropic grid coordinates are discussed. For boundary conditions where the lapse arises as a linear combination of odd and even lapse, two integrals are introduced which characterize the overall slice stretching. Favorable boundary conditions are then derived which make slice stretching occur late in numerical simulations. Allowing the lapse to become negative, this requirement leads to lapse functions which approach at late times the odd lapse corresponding to the static Schwarzschild metric. Demanding in addition that a numerically favorable lapse remains non-negative, as result the average of odd and even lapse is obtained. At late times the la...
Pilkington, Terry
The classical definition of a black hole in terms of an event horizon relies on global properties of the spacetime. Realistic black holes have matter distributions surrounding them, which negates the asymptotic flatness needed for an event horizon. Using the (quasi-)local concept of marginally trapped surfaces, we investigate the Schwarzschild spacetime distorted by an axisymmetric matter distribution. We determine that it is possible to locate a future outer trapping horizon for a given foliation within certain value ranges of multipole moments. Furthermore, we show that there are no marginally trapped surfaces for arbitrary values of the multipole moment magnitudes. KEYWORDS: SCHWARZSCHILD; BLACK HOLE; DISTORTED SPACETIME; MARGINALLY TRAPPED SURFACE; FUTURE OUTER TRAPPING HORIZON
Aranha, R F; Soares, I Damião; Tonini, E V
2008-01-01
We examine the efficiency of gravitational bremsstrahlung production in the process of head-on collision of two boosted Schwarzschild black holes. We constructed initial data for the characteristic initial value problem in Robinson-Trautman spacetimes, that represent two instantaneously stationary Schwarzschild black holes in motion towards each other with the same velocity. The Robinson-Trautman equation was integrated for these initial data using a numerical code based on the Galerkin method. The final resulting configuration is a boosted black hole with Bondi mass greater than the sum of the individual mass of each initial black hole. Two relevant aspects of the process are presented. The first relates the efficiency $\\Delta$ of the energy extraction by gravitational wave emission to the mass of the final black hole. This relation is fitted by a distribution function of non-extensive thermostatistics with entropic parameter $q \\simeq 1/2$; the result extends and validates analysis based on the linearized t...
Scattering of Ricci scalar perturbations from Schwarzschild black holes in modified gravity
Energy Technology Data Exchange (ETDEWEB)
Sibandze, Dan B.; Goswami, Rituparno; Maharaj, Sunil D.; Nzioki, Anne Marie [University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics Statistics and Computer Science, Private Bag X54001, Durban (South Africa); Dunsby, Peter K.S. [University of Cape Town, Department of Mathematics and Applied Mathematics and ACGC, Cape Town (South Africa)
2017-06-15
It has already been shown that the gravitational waves emitted from a Schwarzschild black hole in f(R) gravity have no signatures of the modification of gravity from General Relativity, as the Regge-Wheeler equation remains invariant. In this paper we consider the perturbations of Ricci scalar in a vacuum Schwarzschild spacetime, which is unique to higher order theories of gravity and is absent in General Relativity. We show that the equation that governs these perturbations can be reduced to a Volterra integral equation. We explicitly calculate the reflection coefficients for the Ricci scalar perturbations, when they are scattered by the black hole potential barrier. Our analysis shows that a larger fraction of these Ricci scalar waves are reflected compared to the gravitational waves. This may provide a novel observational signature for fourth order gravity. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Feng, Z.W.; Zu, X.T. [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Li, H.L. [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Shenyang Normal University, College of Physics Science and Technology, Shenyang (China); Yang, S.Z. [China West Normal University, Physics and Space Science College, Nanchong (China)
2016-04-15
We investigate the thermodynamics of Schwarzschild-Tangherlini black hole in the context of the generalized uncertainty principle (GUP). The corrections to the Hawking temperature, entropy and the heat capacity are obtained via the modified Hamilton-Jacobi equation. These modifications show that the GUP changes the evolution of the Schwarzschild-Tangherlini black hole. Specially, the GUP effect becomes susceptible when the radius or mass of the black hole approaches the order of Planck scale, it stops radiating and leads to a black hole remnant. Meanwhile, the Planck scale remnant can be confirmed through the analysis of the heat capacity. Those phenomena imply that the GUP may give a way to solve the information paradox. Besides, we also investigate the possibilities to observe the black hole at the Large Hadron Collider (LHC), and the results demonstrate that the black hole cannot be produced in the recent LHC. (orig.)
Thermodynamic stability of modified Schwarzschild-AdS black hole in rainbow gravity
Kim, Yong-Wan; Park, Young-Jai
2016-01-01
In this paper, we have extended the previous study of the thermodynamics and phase transition of the Schwarzschild black hole in the rainbow gravity to the Schwarzschild-AdS black hole where metric depends on the energy of a probe. Making use of the Heisenberg uncertainty principle and the modified dispersion relation, we have obtained the modified local Hawking temperature and thermodynamic quantities in an isothermal cavity. Moreover, we carry out the analysis of constant temperature slices of a black hole. As a result, we have shown that there also exists another Hawking-Page-like phase transition in which case a locally stable small black hole tunnels into a globally stable large black hole as well as the standard Hawking-Page phase transition from a hot flat space to a black hole.
A virtual trip to the Schwarzschild-de Sitter black hole
Bakala, P; Hledik, S; Stuchlik, Z; Truparova, K
2008-01-01
We developed realistic fully general relativistic computer code for simulation of optical projection in a strong, spherically symmetric gravitational field. Standard theoretical analysis of optical projection for an observer in the vicinity of a Schwarzschild black hole is extended to black hole spacetimes with a repulsive cosmological constant, i.e, Schwarzschild-de Sitter spacetimes. Influence of the cosmological constant is investigated for static observers and observers radially free-falling from static radius. Simulation includes effects of gravitational lensing, multiple images, Doppler and gravitational frequency shift, as well as the amplification of intensity. The code generates images of static observers sky and a movie simulations for radially free-falling observers. Techniques of parallel programming are applied to get high performance and fast run of the simulation code.
Thermodynamic stability of modified Schwarzschild-AdS black hole in rainbow gravity
Energy Technology Data Exchange (ETDEWEB)
Kim, Yong-Wan [Chonbuk National University, Research Institute of Physics and Chemistry, Jeonju (Korea, Republic of); Kim, Seung Kook [Seonam University, Department of Physical Therapy, Namwon (Korea, Republic of); Park, Young-Jai [Sogang University, Department of Physics, Seoul (Korea, Republic of)
2016-10-15
In this paper, we have extended the previous study of the thermodynamics and phase transition of the Schwarzschild black hole in the rainbow gravity to the Schwarzschild-AdS black hole where metric depends on the energy of a probe. Making use of the Heisenberg uncertainty principle and the modified dispersion relation, we have obtained the modified local Hawking temperature and thermodynamic quantities in an isothermal cavity. Moreover, we carry out the analysis of constant temperature slices of a black hole. As a result, we have shown that there also exists another Hawking-Page-like phase transition in which case a locally stable small black hole tunnels into a globally stable large black hole as well as the standard Hawking-Page phase transition from a hot flat space to a black hole. (orig.)
Thermodynamic stability of modified Schwarzschild-AdS black hole in rainbow gravity
Kim, Yong-Wan; Kim, Seung Kook; Park, Young-Jai
2016-10-01
In this paper, we have extended the previous study of the thermodynamics and phase transition of the Schwarzschild black hole in the rainbow gravity to the Schwarzschild-AdS black hole where metric depends on the energy of a probe. Making use of the Heisenberg uncertainty principle and the modified dispersion relation, we have obtained the modified local Hawking temperature and thermodynamic quantities in an isothermal cavity. Moreover, we carry out the analysis of constant temperature slices of a black hole. As a result, we have shown that there also exists another Hawking-Page-like phase transition in which case a locally stable small black hole tunnels into a globally stable large black hole as well as the standard Hawking-Page phase transition from a hot flat space to a black hole.
A rotating universe outside a Schwarzschild black hole where spacetime itself non-uniformly rotates
Saw, Vee-Liem
2014-01-01
We study a non-uniformly rotating universe outside a Schwarzschild black hole by generating a time-dependent manifold of revolution around a straight line. In this simple model where layers of spherical shells of the universe non-uniformly rotate, the Einstein field equations require this phenomenon to be caused by a static mass-energy distribution with time-dependent $T^{\\phi\\phi}$ (quadratic with time) and $T^{r\\phi}=T^{\\phi r}$ (linear with time). This indicates that a time-dependent stress along a certain direction results in a spacetime shift in that direction. For this model however, such material violates the null energy condition. Incidentally, the various coordinate systems describing the Schwarzschild solution can be viewed as arising from the freedom in parametrising the straight line and the radial function in the general method of constructing spacetime by generating manifolds of revolution around a given curve.
Feng, Z W; Zu, X T
2016-01-01
We investigate the thermodynamics of Schwarzschild-Tangherlini black hole in the context of the generalized uncertainty principle. The corrections to the Hawking temperature, entropy and the heat capacity are obtained via the modified Hamilton-Jacobi equation. These modifications show that the GUP changes the evolution of Schwarzschild-Tangherlini black hole. Specially, the GUP effect becomes susceptible when the black hole evaporates down to the order of Planck scale, it makes the Hawking radiating stop and leads to remnant. It finds the endpoint of evaporation is a Planck-scale remnant with zero heat capacity. Those phenomenons imply that the GUP may give a way to solve the information. Besides, we also analysis the possibilities to find the black hole at LHC, and show that the black hole can not be produced in the recent LHC.
Black hole nonmodal linear stability: the Schwarzschild (A)dS cases
Dotti, Gustavo
2016-01-01
The nonmodal linear stability of the Schwarzschild black hole established in Phys.\\ Rev.\\ Lett.\\ {\\bf 112} (2014) 191101 is generalized to the case of nonnegative cosmological constant $\\Lambda$. Two gauge invariant combinations $G_{\\pm}$ of perturbed scalars made out of the Weyl tensor and its first covariant derivative are found such that the map $[h_{\\alpha \\beta}] \\to \\left( G_- \\left([h_{\\alpha \\beta}] \\right), G_+ \\left([h_{\\alpha \\beta}] \\right) \\right)$, $[h_{\\alpha \\beta}]$ an equivalence class under gauge transformations of a solution of the linearized Einstein's equation, is invertible. The way to reconstruct a representative of $[h_{\\alpha \\beta}]$ in terms of $(G_-,G_+)$ is given. It is proved that, for an arbitrary perturbation consistent with the background asymptote, $G_+$ and $G_-$ are bounded in the the outer static region. At large times, the perturbation decays leaving a linearized Kerr black hole around the Schwarzschild or Schwarschild de Sitter background solution. For negative cosmolog...
Interactive visualization of a thin disc around a Schwarzschild black hole
Müller, Thomas; 10.1088/0143-0807/33/4/955
2012-01-01
In the first course of general relativity, the Schwarzschild spacetime is the most discussed analytic solution to Einstein's field equations. Unfortunately, there is rarely enough time to study the optical consequences of the bending of light for some advanced examples. In this paper, we present how the visual appearance of a thin disc around a Schwarzschild black hole can be determined interactively by means of an analytic solution to the geodesic equation processed on current high performance graphical processing units. This approach can, in principle, be customized for any other thin disc in a spacetime with geodesics given in closed form. The interactive visualization discussed here can be used either in a first course of general relativity for demonstration purposes only or as a thesis for an enthusiastic student in an advanced course with some basic knowledge of OpenGL and a programming language.
Thermodynamics and Phase transition of Schwarzschild black hole in Gravity's Rainbow
Feng, Zhong-Wen; Li, Hui-Ling; Zu, Xiao-Tao
2016-01-01
The Planck length and Planck energy should be taken as invariant scales are in agreement with various theories of quantum gravity. In this scenario, the original general relativity can be changed to the so-called gravity's rainbow which produces significant modifications to the black holes' evolution. In this paper, using two kinds of rainbow functions, we investigate the thermodynamics and the phase transition of Schwarzschild black hole in the context of gravity's rainbow theory. Firstly, with the help of the Heisenberg uncertainty principle, we calculate the modified Hawking temperature. Then, based on this modification, we derive the local temperature, free energy and other thermodynamic quantities in an isothermal cavity. Finally, the critical behavior, the thermodynamic stability and phase transition of the rainbow Schwarzschild black hole are analyzed. It turns out that our results are different from the those of Hawking-Page phase transition. Meanwhile, it is found that there are many similarities and...
Exact Schwarzschild-like solution for SU(N) gauge theory
Singleton, D.
1996-09-01
In this paper we extend our previously discovered exact solution for an SU(2) Yang-Mills-Higgs theory, to the general group SU(N+1). Using the first-order formalism of Bogomolny, an exact, spherically symmetric solution for the gauge and scalar fields is found. This solution is similar to the Schwarzschild solution of general relativity, in that the gauge and scalar fields become infinite on a spherical shell of radius r 0= K. However in the Schwarzschild case the singularity at the event horizon is a coordinate singularity while for the present solution the singularity is a true singularity. It is speculated that this solution may give a confinement mechanism for non-Abelian gauge theories, since any particle which carries the SU(N+1) charge would become permanently trapped inside the region r< r 0.
Trajectory bending and gravitational lensing of massive particles in Schwarzschild gravity
Jia, Junji; Yang, Nan
2015-01-01
Both massless light ray and objects with nonzero mass experience trajectory bending in a gravitational field. In this work the bending of trajectories of massive objects in a Schwarzschild spacetime and the corresponding gravitational lensing effects are studied. A {\\it particle sphere} for Schwarzschild black hole (BH) is found with its radius a simple function of the particle velocity and proportional to the BH mass. A single master formula for both the massless and massive particle bending angle is found, in the form of an elliptic function depending on only the velocity and impact parameter measured in central mass. This bending angle is expanded in both large and small velocity limits and large and small impact parameter limits. The corresponding deflection angle for weak and strong gravitational lensing of massive particles are analyzed, and their corrections to the light ray deflection angles are obtained. The dependence of the deflection angles on the source angle and the particle speed is investigate...
O pensamento epistemológico de Karl Popper
Directory of Open Access Journals (Sweden)
José Luiz dos Santos
2007-01-01
Full Text Available Desde a antiguidade, o critério de demarcação entre o que é ciência e o que não é ciência tem sido discutido. A noção que então se tinha de ciência coincidia com a busca do saber absoluto. Tornava-se necessária, para os pensadores gregos, entre eles, Aristóteles, Pitágoras e Descartes, a consolidação de uma distinção precisa entre o saber contingente e o saber necessário, pois o único discurso que poderia satisfazer às exigências do rigor científico era aquele que apontasse, nos fenômenos, conexões causais cuja necessidade pudesse ser demonstrada. Antes de Popper, o pensamento filosófico ocidental atravessou séculos tentando explicar por que nossas teorias frequentemente estavam erradas. Em sua obra fundamental, A Lógica da Pesquisa Científica, Karl Popper coloca em novos termos a discussão epistemológica ao demonstrar que o erro, em vez de ser um mal que pode ser evitado através do recurso a algum procedimento metodológico específico, constitui componente inevitável de qualquer teoria científica, sendo o motor pelo qual a ciência se move. Buscando captar a lógica do desenvolvimento da ciência, Popper inicia sua exposição destruindo aquele que talvez fosse, de todos os princípios filosóficos, o mais caro aos cientistas e à boa parte dos filósofos de seu tempo: o princípio da indução como método de procedimento científico. Neste artigo, abordam-se alguns dos principais tópicos do pensamento popperiano, como o princípio da indução, a concepção de ciência e a falseabilidade. Também se intenta aduzir alguns debates filosóficos, justapondo às opiniões de Popper e de críticos ao seu pensamento. A contestação aludida ao pensamento popperiano advém do professor Thomas S. Kuhn, da Princeton University. Kuhn objeta à opinião de Popper quando este afirma que o cientista é um solucionador de problemas. Para Kuhn, os cientistas são solucionadores de enigmas e não de problemas. Essa posi
Progress in Karl Fischer coulometry using diaphragm-free cells.
Cedergren, A; Jonsson, S
2001-11-15
Different designs of a semiopen, drainable cathode compartment of a medium-sized coulometric Karl Fischer (KF) cell for the determination of water in the range 0.1-500 microg were evaluated. The main criterion for the design was to keep the resistance between the anolyte and catholyte low enough to permit the generation of currents larger than 20 mA (for an output voltage of 28 V). It was found that a good compromise between the size of this current and a minimal influence from diffusing/migrating oxidizable reduction products from the catholyte was achieved by means of an interface having a channel length and diameter of 8 and 2.1 mm, respectively (catholyte volume, approximately 1 mL). To show the general applicability of the concept, the following different types of coulometric reagents suitable for nonpolar and polar samples, as well as for samples containing active carbonyl compounds, were investigated: Hydranal Coulomat A, AD, AK, AG-H (modified with chloroform, Merck), and two homemade methanolic reagents modified with 40% (v/v) chloroform and 50% (v/v) formamide, respectively. Except for Hydranal Coulomat A, the mean value of five consecutive titrations of 50 microg water did not deviate by more than 0.2% from the expected value for all reagents. Draining after every titration was sufficient to obtain accurate results, even for Coulomat A which, when used in the commercial diaphragm-free system of Metrohm, gave values which were about 10% too high. As compared to earlier reported results for diaphragm-free coulometry, the descibed modified cell represents a significant improvement, mainly because of the high accuracy achieved for all types of reagents.
Slice stretching effects for maximal slicing of a Schwarzschild black hole
Reimann, B.
2005-01-01
Slice stretching effects such as slice sucking and slice wrapping arise when foliating the extended Schwarzschild spacetime with maximal slices. For arbitrary spatial coordinates these effects are quantified here in the context of boundary conditions where the lapse arises as a linear combination of odd and even lapse. Favourable boundary conditions are then derived which make the overall slice stretching occur late in numerical simulations. Allowing the lapse to become negative, this require...
Occupation of quasi-bound states by electrons in a Schwarzschild field
Energy Technology Data Exchange (ETDEWEB)
Galtsov, D.V.; Pomerantseva, G.V.; Chizhov, G.A.
1983-08-01
It is noted that quasi-steady states at energies omega less than mu exist near a Schwarzschild black hole. The occupation of these states by massive spinor particles is examined in the Pauli approximation for small black holes (mu)(M) much less than 1. It is shown that, as in the case of a scalar field, the occupation process is a thermal one. 7 references.
Bernar, Rafael P.; Crispino, Luís C. B.; Higuchi, Atsushi
2017-03-01
We analyze the gravitational radiation emitted from a particle in circular motion around a Schwarzschild black hole using the framework of quantum field theory in curved spacetime at tree level. The gravitational perturbations are written in a gauge-invariant formalism for spherically symmetric spacetimes. We discuss the results, comparing them to the radiation emitted by a particle when it is assumed to be orbiting a massive object due to a Newtonian force in flat spacetime.
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.
Formation of Schwarzschild black hole from the scalar field collapse in four-dimensions
Oliveira-Neto, G.; Takakura, F. I.
2003-01-01
We obtain a new self-similar solution to the Einstein's equations in four-dimensions, representing the collapse of a spherically symmetric, minimally coupled, massless, scalar field. Depending on the value of certain parameters, this solution represents the formation of naked singularities and black holes. Since the black holes are identified as the Schwarzschild ones, one may naturally see how these black holes are produced as remnants of the scalar field collapse.
Formation of the remnant close to Planck scale and the Schwarzschild black hole with global monopole
Li, Hui-Ling; Chen, Shuai-Ru
2017-10-01
In this paper, we use the generalized uncertainty principle (GUP) and quantum tunneling method to research the formation of the remnant from a Schwarzschild black hole with global monopole. Based on the corrected Hamilton-Jacobi equation, the corrections to the Hawking temperature, heat capacity and entropy are calculated. We not only find the remnant close to Planck scale by employing GUP, but also research the thermodynamic stability of the black hole remnant according to the phase transition and heat capacity.
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen; YANG Shu-Zheng
2007-01-01
We extend Zhang and Zhao's recent work to the Schwarzschild-anti-de Sitter black hole with topological defect, whose Arnowitt-Deser-Misner (ADM) mass is no longer identical to its mass parameter. The behavior of the tunneling massive particle is investigated and the emission rate is calculated. The result satisfies an underlying unitary theory and takes the same functional form as that of the mass-less particle.
Approximate stress-energy tensor of the massless spin-1/2 field in Schwarzschild spacetime
Matyjasek, J
2005-01-01
The approximate stress-energy tensor of the conformally invariant massless spin-1/2 field in the Hartle-Hawking state in the Schwarzschild spacetime is constructed. It is shown that by solving the conservation equation in conformal space and utilizing the regularity conditions in a physical metric one obtains the stress-energy tensor that is in a good agreement with the numerical calculations. The back reaction of the quantized field upon the spacetime metric is briefly discussed.
Entropy Spectrum of Modified Schwarzschild Black Hole via an Action Invariance
Indian Academy of Sciences (India)
Cheng-Zhou Liu
2014-09-01
The entropy spectrum of a modified Schwarzschild black hole in the gravity’s rainbow are investigated. By utilizing an action invariance of the black hole with the help of Bohr–Sommerfield quantization rule, the entropy spectrum for the modified black hole are calculated. The result of the equally spaced-entropy spectrum being consistent to the original Bekenstein’s spectra 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.
Constant scalar curvature hypersurfaces in the extended Schwarzschild space-time
Pareja, M J
2006-01-01
In this paper we study the spherically symmetric constant scalar curvature hypersurfaces of the extended Schwarzschild space-time. Especially, we analyse the embedding equation and we find the family of solutions or slices that results varying a parameter "c" for fixed constant scalar curvature parameter and fixed time-translation parameter. The parameter "c" represents the amount of variation of volume of the 3-geometry during the 'time'-evolution.
Holographic principle versus Bohr's principle: eternal Schwarzschild-anti-de Sitter geometry
Emelyanov, Slava
2015-01-01
It is shown that Bohr's correspondence principle and the holographic principle are incompatible in the background of an eternal Schwarzschild-anti-de Sitter geometry. The argument is based on the observation that algebraic structures of local quantum field and CFT operators are not equivalent. A CFT Hilbert space representation is elaborated which may correspond to the AdS black hole in the dual theory.
Black hole non-modal linear stability: the Schwarzschild (A)dS cases
Dotti, Gustavo
2016-10-01
The non-modal linear stability of the Schwarzschild black hole established in Dotti (2014 Phys. Rev. Lett. 112 191101) is generalized to the case of a non-negative cosmological constant Λ. Two gauge invariant combinations G ± of perturbed scalars made out of the Weyl tensor and its first covariant derivative are found such that the map [{h}α β ]\\to ({G}-([{h}α β ]),{G}+([{h}α β ])) with domain the set of equivalent classes [{h}α β ] under gauge transformations of solutions of the linearized Einstein’s equation, is invertible. The way to reconstruct a representative of [{h}α β ] in terms of ({G}-,{G}+) is given. It is proved that, for an arbitrary perturbation consistent with the background asymptote, {G}+ and {G}- are bounded in the the outer static region. At large times, the perturbation decays leaving a linearized Kerr black hole around the Schwarzschild or Schwarschild de Sitter background solution. For negative cosmological constant it is shown that there are choices of boundary conditions at the time-like boundary under which the Schwarzschild anti de Sitter black hole is unstable. The root of Chandrasekhar’s duality relating odd and even modes is exhibited, and some technicalities related to this duality and omitted in the original proof of the {{Λ }}=0 case are explained in detail.
Energy Technology Data Exchange (ETDEWEB)
Nordin-Andersson, I.; Cedergren, A.
1987-03-01
Improved conditions for the coulometric determination of trace water in samples containing potentially interfering substances like aldehydes and ketones were obtained by using a formamide-based, rapidly reacting Karl Fischer reagent in which methanol was replaced by 2-methoxyethanol. The shape of the potentiometric titration curves obtained by titrating spent Karl Fischer reagents with iodine indicates a less degree of triiodide formation in the presence of formamide. The corresponding increase in iodine results in a more rapid overall reaction rate since the reaction involving iodine is much more rapid than that with triiodide. For water amounts corresponding to less than 0.1% the stoichiometry of the Karl Fischer reaction was found to be 1:1, relatively independent of the concentration of 2-methoxyethanol. For larger amounts of water this stoichiometric ratio was attained by using a reagent containing 2-methoxyethanol/formamide 80/20 (v/v), 0.6 M imidazole, and 0.4 M sulfur dioxide.
The Karl G. Jansky Very Large Array Sky Survey (VLASS)
Myers, Steven T.; Baum, S. A.; Chandler, C. J.
2014-01-01
The Karl G. Jansky Very Large Array is a recently completed rejuvenation of the VLA, providing observers with significantly increased continuum sensitivity and spectral survey speeds (by factors of 100 or more in select cases) from 1-50 GHz and in key bands below 1 GHz. Given the potential for new centimeter-wavelength sky surveys with this enhanced facility, the NRAO VLA Sky Survey (VLASS) has been initiated to explore the science and technical opportunities of a new large survey. A community-led Science Survey Group (SSG) will define the science program and key components of VLASS, and NRAO will support its technical design and implementation. The VLASS could start observing in early 2015, with the data available immediately with no proprietary period and science data products provided to the community in a timely manner. The new VLA can image young stars and massive black holes, measure the strength and topology of the cosmic magnetic field, follow the rapid evolution of energetic phenomena, and study the formation and evolution of stars, galaxies, AGN, and the Universe itself. We can follow the evolution of gas and galaxies and particles and fields to bridge the eras from cosmic dawn to the dawn of new worlds. To address these and other key science challenges requires the VLASS to address a number of key challenges in data management, computation, image processing, and analysis. The development and implementation of capable, efficient, and robust pipeline processing of data, and the production of a basic suite of science data products such as images and catalogs, are all high priorities for VLASS. We will describe the salient capabilities of the Jansky VLA, and highlight complementarity with multi-wavelength multi-messenger sky surveys with other facilities, ultimately leading into the era of the LSST. Exemplary VLA science and commissioning observations will illustrate these features. We will also summarize the outcome of the public NRAO VLASS Science Planning
Rheumatoid arthritis, Proteus, anti-CCP antibodies and Karl Popper.
Ebringer, Alan; Rashid, Taha; Wilson, Clyde
2010-02-01
Rheumatoid arthritis (RA) is a crippling joint disease affecting over 20 million people worldwide. The cause of RA is most probably linked to the triad of microbial trigger, genetic association and autoimmunity and can be explained using the philosophical method of Karl Popper or Popperian sequences. Ten "Popper sequences" have been identified which point to the urinary microbe Proteus mirabilis as the cause of RA: Popper sequence 1 establishes that HLA-DR4 lymphocytes injected into a rabbit evoke specific antibodies against Proteus bacteria. Popper sequence 2 establishes that antibodies to Proteus bacteria are present in RA patients from 14 different countries. Popper sequence 3 establishes that antibodies to Proteus bacteria in RA patients are disease specific since no such antibodies are found in other conditions. Popper sequence 4 establishes that when RA patients have high titres of antibodies to Proteus such bacteria are found in urinary cultures. Popper sequence 5 establishes that only Proteus bacteria and no other microbes evoke significantly elevated antibodies in RA patients. Popper sequence 6 establishes that the "shared epitope" EQR(K)RAA shows "molecular mimicry" with the sequence ESRRAL found in Proteus haemolysin. Popper sequence 7 establishes that Proteus urease contains a sequence IRRET which has "molecular mimicry" with LRREI found in collagen XI of hyaline cartilage. Popper sequence 8 establishes that sera obtained from RA patients have cytopathic properties against sheep red cells coated with the cross-reacting EQR(K)RAA and LRREI self-antigen peptides. Popper sequence 9 establishes that Proteus sequences in haemolysin and urease as well as the self antigens, HLA-DR1/4 and collagen XI, each contain an arginine doublet, thereby providing a substrate for peptidyl arginine deiminase (PAD) to give rise to citrulline, which is the main antigenic component of CCP, antibodies to which are found in early cases of RA. Popper sequence 10 establishes that
[The Hygienist Karl Roelcke, M.D. (1907-1982). Annotations to the family biography].
Mildenberger, Florian G
2016-01-01
Volker Roelcke, the well-known historian of medicine, wrote a biographical sketch on his father's role in National Socialism. Karl Roelcke (1907-1982) was an important hygienist at the University of Heidelberg and assistant to Ernst Rodenwaldt (1878-1965). Attempts to discuss the Nazi issue with his father directly ended unsuccessfully in the 1970s. In his essay of 2014, Volker Roelcke portrayed his father as quite sophisticated, but did not mention all aspects of his work. The present essay therefore offers new insights into the person of Karl Roelcke which are not constrained by family interests.
Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Jia; Sun, Guohua; Li, Hongmei
2012-10-15
Certified reference materials (CRMs) of water content are widely used in the calibration and validation of Karl Fischer coulometry and volumetry. In this study, the water content of the water saturated 1-octanol (WSO) CRM was certified by Karl Fischer coulometry, volumetry and quantitative nuclear magnetic resonance (Q NMR). The water content recovery by coulometry was 99.76% with a diaphragm-less electrode and Coulomat AG anolyte. The relative bias between the coulometry and volumetry results was 0.06%. In Q NMR, the water content of WSO is traceable to the International System (SI) of units through the purity of internal standard. The relative bias of water content in WSO between Q NMR and volumetry was 0.50%. The consistency of results for these three independent methods improves the accuracy of the certification of the RM. The certified water content of the WSO CRM was 4.76% with an expanded uncertainty of 0.09%.
Schmadel, Lutz D.; Guski-Leinwand, Susanne
2011-08-01
Karl Julius Lohnert (1885-1944) with his double biography as astronomer and psychologist is hardly known in both fields. As a student of astronomy in Heidelberg, Lohnert discovered a couple of minor planets and he dedicated one to his PhD supervisor, the famous Leipzig professor for philosophy, Wilhelm Wundt. This connection is discussed for the first time almost one century after the naming of (635) Vundtia. The paper elucidates some biographical stations of Lohnert.
The Potassium-Argon Laser Experiment (KarLE): In Situ Geochronology for Mars and Beyond
Cohen, Barbara A.
2014-01-01
The search for life in the solar system depends upon discovering the right moments in planetary evolution: when habitable environments existed, when they declined, and when geologic processes operated to preserve traces of life after death. However, an incomplete knowledge of absolute Martian geochronology limits our ability to understand the timing of Martian evolutionary milestones, major climate changes, and stratigraphic epochs [1, 2]. Absolute dating relates these habitability markers to planetarywide geologic, atmospheric, and climate history places, and ties their occurrence to the history of the solar system, especially the Earth-Moon system and the timescale of evolution of life on Earth. KArLE is being developed to anchor the relative timeline of geological events to an absolute chronology that puts Mars into a wider solar system context. KArLE makes its measurements on rock samples that can be obtained by landers or rovers and inserted into a small, mechanically simple chamber. KArLE interrogates the samples using laser-induced breakdown spectrocopy (LIBS), mass spectrometry, and optical imaging. The KArLE experiment is flexible enough to accommodate any partner providing these instrument components, a creative approach that extends the ability of mission payloads to accomplish an additional highly-desirable science measurement for low cost and risk and minimal extra hardware.
Tänapäeva tantsuteatri mitu palet / Heili Einasto, Karl Toepfer
Einasto, Heili
2015-01-01
Vestlus San Jose ülikooli professori Karl Toepferiga nüüdisaegsest Eesti tantsuteatrist - I. Tuksami "Vassilissa", E. Tubina ja M Kesleri "Kratt", T. Olleski jt. "HTK", G. Reynoldsi ja S. Stubbsi "Gatsby", N. Rota ja G. Madia "La Dolce Vita", A. Toikka "Faust"
Recalling Karl Jaspers' Classic: The Idea of the University. IHE Perspectives.
Fincher, Cameron
This essay revisits Karl Jaspers' classic, "The Idea of the University." Jaspers was reinstated as president of Heidelberg University in 1945, and he presided over its rebuilding. His book, "The Idea of the University," written in 1946, was published in English 13 years later. It interprets an ideal of the university and emphasizes the purposes…
Vendade Karl ja Artur Säre elukäigu salaniidistik / Valdur Ohmann
Ohmann, Valdur
2003-01-01
EKP I sekretäri Karl Säre ja tema vanema venna Artur Säre (Männi) elu ja tegevuse ülevaade. Artur Säre oli NSVL poliitilise esinduse teenistuses Hiina RV, NSVL Välisasjade Rahvakomissariaadi ja ENSV Ministrite Nõukogu juures
Qi, Jie
This paper explores how educators would raise different questions about educational issues by using Karl Marx's framework, Antonio Gramsci's conception, and Michel Foucault's notions, respectively. First, the paper compares the historical perspectives of Marx and Foucault. Marx concludes that history is a progressive linear production and that…
USA presidendi üks peamisi nõunikke Karl Rove lahkub ametist / Kaivo Kopli
Kopli, Kaivo
2007-01-01
1993. aastast praeguse USA presidendi George B. Bushiga koos töötanud Karl Rove lahkub ametist perekonna huvides. K. Rove on uurimise all olnud seoses CIA agendi Valerie Plame'i paljastamisega, Senati komitee kuulas teda üle kaheksa föderaalprokuröri vallandamise uurimise raames
El huracán Karl: concepciones sobre su origen en una comunidad de Veracruz
National Research Council Canada - National Science Library
Arturo Marinero Heredia; María José García Oramas
2015-01-01
... por el huracán Karl en 2010, en el municipio de La Antigua, Veracruz. Los datos se obtuvieron de entrevistas a informantes claves y grupos focales, además de la revisión de notas periodísticas...
Karl Ristikivi rändav Arkaadia / Janika Kronberg, Brita Melts
Kronberg, Janika, 1963-
2012-01-01
Artikkel jälgib Arkaadia-motiivi arengut Karl Ristikivi loomingus, toetudes nii autori poolt läbikäidud maastikele kui ka kunstikriitiku ja teoreetiku Simon Schama töödele. Käsitletakse ka Arkaadia motiivi Euroopa kultuuriloos
Lidar - nesbõvshajasja estonskaja "nokia" / Karl Rebane ; interv. Julia Rodina
Rebane, Karl, 1926-2007
2006-01-01
Eesti NSV teadlaste poolt välja töötatud laserseade lidar, seadme ehitamisest, töötamise põhimõttest ja kasutusvaldkonnast. Akadeemik Karl Rebase sõnul ei oleks sellise ulatusega Läänemere saastamist juhtunud, kui Eestil oleks normaalne ökoloogilise kontrolli süsteem. Poliitikute suhtumisest kodumaise teaduse arengusse
The Psychology of Thinking, Animal Psychology, and the Young Karl Popper
ter Hark, M.R.M.
2004-01-01
In the 1920s, Karl Popper wrote two large manuscripts on psychology that he never published. in his autobiography, Unended Quest, he attempts to reduce the importance of his work in psychology as much as possible, and in his philosophical work he is an antipsychologist. However, in this article, it
Burgess, Tyrrell; Swann, Joanna
2003-01-01
Addresses the question of why Karl Popper's work has been disregarded or rejected for educational improvement and suggests a series of impediments to an acceptance of Popper's ideas. Outlines a set of principle which if adopted as a basis for practice could lead to significant improvement. (EV)
Ideal i realnost : Karl von Gershelman - poet-hudozhnik / Mai Levin
Levin, Mai, 1942-
2005-01-01
Eesti päritolu kunstniku Elisabeth Rosendorff-Hoerschelmanni (1898-1984) ja Eestiga seotud kunstniku ja kirjaniku Karl von Hoerschelmanni (1899-1951) elust ja loomingust. 2004. a. augustis-oktoobris oli kunstnike tööde näitus Adamson-Ericu muuseumis
Ideal i realnost : Karl von Gershelman - poet-hudozhnik / Mai Levin
Levin, Mai, 1942-
2005-01-01
Eesti päritolu kunstniku Elisabeth Rosendorff-Hoerschelmanni (1898-1984) ja Eestiga seotud kunstniku ja kirjaniku Karl von Hoerschelmanni (1899-1951) elust ja loomingust. 2004. a. augustis-oktoobris oli kunstnike tööde näitus Adamson-Ericu muuseumis
Karl Marx in One Lesson (1818-1883). Series on Public Issues No. 6.
Pejovich, Steve
This booklet, one of a series intended to apply economic principles to major social and political issues of the day, starts from the premise that Marxism is a threat to our way of life and offers a critique of fundamental components of the social movement Marx created. The first of six subsections focuses on sources of influence on Karl Marx…
Urea as the basic component in pyridine-free Karl Fischer reagent
Bos, M.
1984-01-01
A solution of urea, sulphur dioxide and sodium salicylate in methanol is proposed as the solvent in the Karl Fischer titration, with a separate iodine solution as titrant. Comparison of the performance of this solvent with that of some commercial reagents shows that it is has distinct advantages for
Lidar - nesbõvshajasja estonskaja "nokia" / Karl Rebane ; interv. Julia Rodina
Rebane, Karl, 1926-2007
2006-01-01
Eesti NSV teadlaste poolt välja töötatud laserseade lidar, seadme ehitamisest, töötamise põhimõttest ja kasutusvaldkonnast. Akadeemik Karl Rebase sõnul ei oleks sellise ulatusega Läänemere saastamist juhtunud, kui Eestil oleks normaalne ökoloogilise kontrolli süsteem. Poliitikute suhtumisest kodumaise teaduse arengusse
Reaction rates between water and some modified rapidly-reacting Karl Fischer reagents.
Cedergren, A
1978-04-01
Rate constants were determined for the reaction between water and various modified Karl Fischer reagents containing formamide, dimethylformamide or N-methylformamide. It was shown that the reaction rate can be increased by a factor of 100 by using a reagent containing 40% v/v formamide in pyridine compared to that obtained by use of the conventional methanolic reagent.
17. oktoober 1905 - 1. märts 1917 / Karl Ast Rumor
Ast Rumor, Karl
2007-01-01
Üheteistkümneaastasest perioodist Karl Asti tagasivaatava isikliku pilgu läbi. Autor vabanes Riia vanglast oktoobrimanifesti põhjal. Ees ootasid uued vangistused. K. Asti isiklik mälestus Aleksandr Kerenskist. Varem ilmunud : "Pealinna Teataja" 9. märts 1917, nr. 3
Developement of the Potassium-Argon Laser Experiment (KArLE) for In Situ Geochronology
Cohen, Barbara A.
2012-01-01
Absolute dating of planetary samples is an essential tool to establish the chronology of geological events, including crystallization history, magmatic evolution, and alteration. Thus far, radiometric geochronology of planetary samples has only been accomplishable in terrestrial laboratories on samples from dedicated sample return missions and meteorites. In situ instruments to measure rock ages have been proposed, but none have yet reached TRL 6, because isotopic measurements with sufficient resolution are challenging. We have begun work under the NASA Planetary Instrument Definition and Development Program (PIDDP) to develop the Potassium (K) - Argon Laser Experiment (KArLE), a novel combination of several flight-proven components that will enable accurate KAr isochron dating of planetary rocks. KArLE will ablate a rock sample, measure the K in the plasma state using laser-induced breakdown spectroscopy (LIBS), measure the liberated Ar using quadrupole mass spectrometry (QMS), and relate the two by measuring the volume of the abated pit using a optical methods such as a vertical scanning interferometer (VSI). Our preliminary work indicates that the KArLE instrument will be capable of determining the age of several kinds of planetary samples to 100 Myr, sufficient to address a wide range of geochronology problems in planetary science. Additional benefits derive from the fact that each KArLE component achieves analyses common to most planetary surface missions.
Tänapäeva tantsuteatri mitu palet / Heili Einasto, Karl Toepfer
Einasto, Heili
2015-01-01
Vestlus San Jose ülikooli professori Karl Toepferiga nüüdisaegsest Eesti tantsuteatrist - I. Tuksami "Vassilissa", E. Tubina ja M Kesleri "Kratt", T. Olleski jt. "HTK", G. Reynoldsi ja S. Stubbsi "Gatsby", N. Rota ja G. Madia "La Dolce Vita", A. Toikka "Faust"
17. oktoober 1905 - 1. märts 1917 / Karl Ast Rumor
Ast Rumor, Karl
2007-01-01
Üheteistkümneaastasest perioodist Karl Asti tagasivaatava isikliku pilgu läbi. Autor vabanes Riia vanglast oktoobrimanifesti põhjal. Ees ootasid uued vangistused. K. Asti isiklik mälestus Aleksandr Kerenskist. Varem ilmunud : "Pealinna Teataja" 9. märts 1917, nr. 3
Mineviku kummitused : Stasi arhiivist leiti Karl-Heinz Kurrase aktid / Aino Siebert
Siebert, Aino
2009-01-01
On ilmsiks tulnud dokumendid, mis tõestavad, et Saksa DV Riikliku Julgeolekuministeeriumi agent Karl-Heinz Kurras tappis Lääne-Berliinis Iraani monarhi visiidi ajal 1967. aasta 2. juunil toimunud meeleavalduste käigus üliõpilase Benno Ohnesorgi
Sbierski, Jan
2015-01-01
The maximal analytic Schwarzschild spacetime is manifestly inextendible as a Lorentzian manifold with a twice continuously differentiable metric. In this paper, we prove the stronger statement that it is even inextendible as a Lorentzian manifold with a continuous metric. To capture the obstruction to continuous extensions through the curvature singularity, we introduce the notion of the spacelike diameter of a globally hyperbolic region of a Lorentzian manifold with a merely continuous metric and give a sufficient condition for the spacelike diameter to be finite. The investigation of low-regularity inextendibility criteria is motivated by the strong cosmic censorship conjecture.
Temperature oscillations of a gas in circular geodesic motion in the Schwarzschild field
Zimdahl, Winfried
2014-01-01
We investigate a Boltzmann gas in equilibrium with its center of mass moving on a circular geodesics in the Schwarzschild field. As a consequence of Tolman's law we find that a central comoving observer measures oscillations of the temperature and of other thermodynamic quantities with twice the frequencies that are known from test-particle motion. We apply this scheme to the gas dynamics in the gravitational fields of the planets of the solar system as well as to strong-field configurations of neutron stars and black holes.
Temperature oscillations of a gas in circular geodesic motion in the Schwarzschild field
Zimdahl, Winfried; Kremer, Gilberto M.
2015-01-01
We investigate a Boltzmann gas at equilibrium with its center of mass moving on a circular geodesic in the Schwarzschild field. As a consequence of Tolman's law we find that a central comoving observer measures oscillations of the temperature and of other thermodynamic quantities with twice the frequencies that are known from test-particle motion. We apply this scheme to the gas dynamics in the gravitational fields of the planets of the Solar System as well as to strong-field configurations of neutron stars and black holes.
Modified de Broglie-Bohm approach to the Schwarzschild black hole
Institute of Scientific and Technical Information of China (English)
Wang Bo-Bo
2008-01-01
A modified de Broglie-Bohm approach is generalized to the Schwarzschild black hole. By using this method, the quantum potential and the quantum trajectories of the black hole are investigated. And we find that the linear combination of two particular solutions of the black hole wavefunction is not physical although each of them is physical, if we think that the quantum gravity should reduce into its corresponding classical counterpart in which the gravity vanishes. It seems to confirm the argument, given by Alwis and MacIntire, that a possible resolution on the quantum gravity is to give up the superposition principle.
Lu, Xu; Xie, Yi
2016-01-01
We analyse strong gravitational field time delay for photons coupled to the Weyl tensor in a Schwarzschild black hole. By making use of the method of strong deflection limit, we find that these time delays between relativistic images are significantly affected by polarization directions of such a coupling. A practical problem about determination of the polarization direction by observations is investigated. It is found that if the first and second relativistic images can be resolved, the measurement of time delay can more effectively improve detectability of the polarization direction.
The fate of Schwarzschild-de Sitter Black Holes in $f(R)$ gravity
Addazi, Andrea
2016-01-01
The semiclassical effects of antievaporating black holes can be discussed in the framework of $f(R)$ gravity. In particular, the Bousso-Hawking-Nojiri-Odinstov antievaporation instability of degenerate Schwarzschild-de Sitter black holes (the so called Nariai space-time) leads to a dynamical increasing of black hole horizon in $f(R)$ gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces become space-like surfaces before the effective Bekenstein-Hawking emission time. As a consequence, Bousso-Hawking thermal radiation cannot be emitted in an antievaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.
Sommerfeld's Quantum Condition of Action and the Spectra of Quantum Schwarzschild Black Hole
Institute of Scientific and Technical Information of China (English)
LIU Liao; PEI Shou-Yong
2004-01-01
If the situation of quantum gravity nowadays is nearly the same as that of quantum mechanics in its early time of Bohr and Sommerfeld, then a first-step study of the quantum gravity under Sommerfeld's quantum condition of action might be helpful. We present the spectra of quantum Schwarzschild black hole in non-relativistic quantum mechanics. It is found that the quantum of area is 8π/3 l2p the quantum of entropy is 2π/3kB and the Hawking evaporation will cease when the black hole reaches the ground state m = 1/2√3mp.
$1/f$ fluctuations in spinning-particle motions around Schwarzschild black hole
Koyama, H; Konishi, T; Kiuchi, Kenta; Konishi, Tetsuro; Koyama, Hiroko
2007-01-01
We study the properties of chaos in spinning-particle motions in Schwarzschild spacetime. We characterize the chaos in the motions using the power spectrum. We discover that the power spectrum shows not only white noise but also $1/f$-type fluctuation, depending on the value of the spin and the angular momentum of the test particle. We obtain the phase diagram for the properties of the chaos. Furthermore, we suggest that the origin of the $1/f$ fluctuations is the ``stagnant motions,'' itinerating among regular orbits (tori).
A Dynamical Systems Analysis of Axisymmetric Accretion in a Schwarzschild Black Hole
Iram, Shamreen
2014-01-01
Stationary, inviscid, axi-symmetric, rotating, transonic accretion flow has been studied in a general relativistic framework, in the Schwarzschild metric; for three different flow geometries - under both polytropic and isothermal conditions. The equilibrium points of the underlying fluid system have been located and an eigenvalue based linear dynamical systems analysis of these critical points has been carried out, to obtain a taxonomic scheme of the critical points. It has hence been shown that only saddle and centre type points can arise for real, physical transonic flow.
Exact gravitational lensing in conformal gravity and Schwarzschild-de Sitter spacetime
Lim, Yen-Kheng
2016-01-01
An exact solution is obtained for the gravitational bending of light in static, spherically symmetric metrics which includes the Schwarzschild-de Sitter (SdS) spacetime and also the Mannheim-Kazanas (MK) metric of conformal Weyl gravity. From the exact solution, we obtain a small bending-angle approximation for a lens system where the source, lens and observer are co-aligned. This expansion improves previous calculations where we systematically avoid parameter ranges which correspond to non-existent null trajectories. The linear coefficient $\\gamma$ characteristic to conformal gravity is shown to contribute enhanced deflection compared to the angle predicted by General Relativity for small $\\gamma$.
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 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
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.
Trapped and marginally trapped surfaces in Weyl-distorted Schwarzschild solutions
Pilkington, Terry; Fitzgerald, Joseph; Booth, Ivan
2011-01-01
To better understand the allowed range of black hole geometries, we study Weyl-distorted Schwarzschild solutions. They always contain trapped surfaces, a singularity and an isolated horizon and so should be understood to be (geometric) black holes. However we show that for large distortions the isolated horizon is neither a future outer trapping horizon (FOTH) nor even a marginally trapped surface: slices of the horizon cannot be infinitesimally deformed into (outer) trapped surfaces. We consider the implications of this result for popular quasilocal definitions of black holes.
Trapped and marginally trapped surfaces in Weyl-distorted Schwarzschild solutions
Energy Technology Data Exchange (ETDEWEB)
Pilkington, Terry; Melanson, Alexandre; Fitzgerald, Joseph [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, NL A1B 3X7 (Canada); Booth, Ivan, E-mail: tpilkington@mun.ca, E-mail: ibooth@mun.ca [Department of Mathematics and Statistics, Memorial University of Newfoundland, NL A1C 5S7 (Canada)
2011-06-21
To better understand the allowed range of black hole geometries, we study Weyl-distorted Schwarzschild solutions. They always contain trapped surfaces, a singularity and an isolated horizon and so should be understood to be (geometric) black holes. However, we show that for large distortions the isolated horizon is neither a future outer trapping horizon nor even a marginally trapped surface: slices of the horizon cannot be infinitesimally deformed into (outer) trapped surfaces. We consider the implications of this result for popular quasilocal definitions of black holes.
Trapped and marginally trapped surfaces in Weyl-distorted Schwarzschild solutions
Pilkington, Terry; Melanson, Alexandre; Fitzgerald, Joseph; Booth, Ivan
2011-06-01
To better understand the allowed range of black hole geometries, we study Weyl-distorted Schwarzschild solutions. They always contain trapped surfaces, a singularity and an isolated horizon and so should be understood to be (geometric) black holes. However, we show that for large distortions the isolated horizon is neither a future outer trapping horizon nor even a marginally trapped surface: slices of the horizon cannot be infinitesimally deformed into (outer) trapped surfaces. We consider the implications of this result for popular quasilocal definitions of black holes.
Waves in General Relativistic Two-fluid Plasma around a Schwarzschild Black Hole
Rahman, M Atiqur
2010-01-01
Waves propagating in the relativistic electron-positron or ions plasma are investigated in a frame of two-fluid equations using the 3+1 formalism of general relativity developed by Thorne, Price and Macdonald (TPM). The plasma is assumed to be freefalling in the radial direction toward the event horizon due to the strong gravitational field of a Schwarzschild black hole. The local dispersion relations for transverse and longitudinal waves have been derived, in analogy with the special relativistic formulation as explained in an earlier paper, to take account of relativistic effects due to the event horizon using WKB approximation
Revisit on the thermodynamic stability of the noncommutative Schwarzschild black hole
Ma, Meng-Sen; Liu, Yan-Song; Li, Huai-Fan
In two frameworks, we discuss the thermodynamic stability of noncommutative geometry inspired Schwarzschild black hole (NCSBH). Under the horizon thermodynamics of black holes, we show that the NCSBH cannot be thermodynamically stable if requiring positive temperature. We note the inconsistency in the work of Larrañaga et al. and propose an effective first law of black hole thermodynamics for the NCSBH to eliminate the inconsistency. Based on the effective first law, we recalculate the heat capacity and the thermodynamic curvature by means of geometrothermodynamics (GTD) to revisit the thermodynamic stability.
Osculating orbits in Schwarzschild spacetime, with an application to extreme mass-ratio inspirals
Pound, Adam
2007-01-01
We present a method to integrate the equations of motion that govern bound, accelerated orbits in Schwarzschild spacetime. At each instant the true worldline is assumed to lie tangent to a reference geodesic, called an osculating orbit, such that the worldline evolves smoothly from one such geodesic to the next. Because a geodesic is uniquely identified by a set of constant orbital elements, the transition between osculating orbits corresponds to an evolution of the elements. In this paper we derive the evolution equations for a convenient set of orbital elements, assuming that the force acts only within the orbital plane; this is the only restriction that we impose on the formalism, and we do not assume that the force must be small. As an application of our method, we analyze the relative motion of two massive bodies, assuming that one body is much smaller than the other. Using the hybrid Schwarzschild/post-Newtonian equations of motion formulated by Kidder, Will, and Wiseman, we treat the unperturbed motion...
Slice stretching effects for maximal slicing of a Schwarzschild black hole
Reimann, Bernd
2005-11-01
Slice stretching effects such as slice sucking and slice wrapping arise when foliating the extended Schwarzschild spacetime with maximal slices. For arbitrary spatial coordinates these effects are quantified here in the context of boundary conditions where the lapse arises as a linear combination of odd and even lapse. Favourable boundary conditions are then derived which make the overall slice stretching occur late in numerical simulations. Allowing the lapse to become negative, this requirement leads to lapse functions which approach at late times the odd lapse corresponding to the static Schwarzschild metric. Demanding, however, that a numerically favourable lapse remains non-negative, as a result the average of odd and even lapse is obtained. At late times the lapse with zero gradient at the puncture arising for the puncture evolution is precisely of this form. Finally, analytic arguments are given on how slice stretching effects can be avoided. Here the excision technique and the working mechanism of the shift function are studied in detail.
The Schwarzschild metric and the Friedmann equations from Newtonian Gravitational collapse
Guendelman, Eduardo I; Granit, Gilad; Ygael, Tomer; Rohrhofer, Christian
2015-01-01
As is well known, the 0 - 0 component of the Schwarzschild space can be obtained by the requirement that the geodesic of slowly moving particles match the Newtonian equation. Given this result, we show here that the remaining components can be obtained by requiring that the inside of a Newtonian ball of dust matched at a free falling radius with the external space determines that space to be Schwarzschild, if no pathologies exist. Also we are able to determine that the constant of integration that appears in the Newtonian Cosmology, coincides with the spatial curvature of the FLRW metric. These results are of interest at least in two respects, one from the point of view of its pedagogical value of teaching General Relativity without in fact using Einstein's equation and second, the fact that some results attributed to General Relativity can be obtained without using General Relativity indicates that these results are more general than the particular dynamics speci?ed by General Relativity.
(Non-adiabatic) string creation on nice slices in Schwarzschild black holes
Puhm, Andrea; Ugajin, Tomonori
2016-01-01
Nice slices have played a pivotal role in the discussion of the black hole information paradox as they avoid regions of strong spacetime curvature and yet smoothly cut through the infalling matter and the outgoing Hawking radiation, thus, justifying the use of low energy field theory. To avoid information loss it has been argued recently, however, that local effective field theory has to break down at the horizon. To assess the extent of this breakdown in a UV complete framework we study string-theoretic effects on nice slices in Schwarzschild black holes. Our purpose is two-fold. First, we use nice slices to address various open questions and caveats of arXiv:1402.1486 where it was argued that boost-enhanced non-adiabatic string-theoretic effects at the horizon could provide a dynamical mechanism for the firewall. Second, we identify two non-adiabatic effects on nice slices in Schwarzschild black holes: pair production of open strings near the horizon enhanced by the presence of the infinite tower of highly ...
Dotti, Gustavo; Gleiser, Reinaldo J.
2009-11-01
The coupled equations for the scalar modes of the linearized Einstein equations around Schwarzschild's spacetime were reduced by Zerilli to a (1+1) wave equation \\partial ^2 \\Psi _z / \\partial t^2 + {\\cal H} \\Psi _z =0 , where {\\cal H} = -\\partial ^2 / \\partial x^2 + V(x) is the Zerilli 'Hamiltonian' and x is the tortoise radial coordinate. From its definition, for smooth metric perturbations the field Ψz is singular at rs = -6M/(ell - 1)(ell +2), with ell being the mode harmonic number. The equation Ψz obeys is also singular, since V has a second-order pole at rs. This is irrelevant to the black hole exterior stability problem, where r > 2M > 0, and rs 0, and the singularity appears in the relevant range of r (0 value of M. The relation of \\hat{\\Psi} to Ψz is provided by an intertwiner operator. The spatial pieces of the (1 + 1) wave equations that \\hat{\\Psi} and Ψz obey are related as a supersymmetric pair of quantum Hamiltonians {\\cal H} and \\hat{\\cal H} . For Mproof of the linear instability of the Schwarzschild naked singularity, by showing that a previously found unstable mode belongs to a complete basis of \\hat{\\cal H} in {\\cal D} , and thus is excitable by generic initial data. This is further illustrated by numerically solving the linearized equations for suitably chosen initial data.
Perturbation of a Schwarzschild Black Hole Due to a Rotating Thin Disk
Čížek, P.; Semerák, O.
2017-09-01
Will, in 1974, treated the perturbation of a Schwarzschild black hole due to a slowly rotating, light, concentric thin ring by solving the perturbation equations in terms of a multipole expansion of the mass-and-rotation perturbation series. In the Schwarzschild background, his approach can be generalized to perturbation by a thin disk (which is more relevant astrophysically), but, due to rather bad convergence properties, the resulting expansions are not suitable for specific (numerical) computations. However, we show that Green’s functions, represented by Will’s result, can be expressed in closed form (without multipole expansion), which is more useful. In particular, they can be integrated out over the source (a thin disk in our case) to yield good converging series both for the gravitational potential and for the dragging angular velocity. The procedure is demonstrated, in the first perturbation order, on the simplest case of a constant-density disk, including the physical interpretation of the results in terms of a one-component perfect fluid or a two-component dust in a circular orbit about the central black hole. Free parameters are chosen in such a way that the resulting black hole has zero angular momentum but non-zero angular velocity, as it is just carried along by the dragging effect of the disk.
Modelo An\\'alogo Ac\\'ustico ao Buraco Negro de Schwarzschild
Toniato, Júnior Diniz
2011-01-01
Um fluido em movimento pode agir sobre o som da mesma forma que os espa\\c{c}o-tempos curvos podem influenciar na trajet\\'oria da luz na relatividade geral. Com isso, pode-se descrever a propaga\\c{c}\\~ao dessas ondas sonoras atrav\\'es de uma m\\'etrica efetiva, sob a qual elas seguir\\~ao geod\\'esicas nulas. Esta disserta\\c{c}\\~ao faz uma revis\\~ao destes estudos concentrando-se em uma analogia ac\\'ustica para um buraco negro de Schwarzschild, demonstrando suas vantagens e limita\\c{c}\\~oes quando aplicada para o estudo da teoria de Hawking. A fluid in moviment can act on the sound the same way that curved space-time can influence on light trajectory in the general relativity. So, one can describe the propagation these sound waves through an effective metric, under wich they will follow null geodesics. This thesis makes a review of these studies focusing in an analogy to Schwarzschild black hole using an acoustic system, showing its advantages and limitations when applied in the study of Hawking's theory.
On analytic solutions of wave equations in regular coordinate systems on Schwarzschild background
Philipp, Dennis
2015-01-01
The propagation of (massless) scalar, electromagnetic and gravitational waves on fixed Schwarzschild background spacetime is described by the general time-dependent Regge-Wheeler equation. We transform this wave equation to usual Schwarzschild, Eddington-Finkelstein, Painleve-Gullstrand and Kruskal-Szekeres coordinates. In the first three cases, but not in the last one, it is possible to separate a harmonic time-dependence. Then the resulting radial equations belong to the class of confluent Heun equations, i.e., we can identify one irregular and two regular singularities. Using the generalized Riemann scheme we collect properties of all the singular points and construct analytic (local) solutions in terms of the standard confluent Heun function HeunC, Frobenius and asymptotic Thome series. We study the Eddington-Finkelstein case in detail and obtain a solution that is regular at the black hole horizon. This solution satisfies causal boundary conditions, i.e., it describes purely ingoing radiation at $r=2M$. ...
Schwarzschild-like exteriors for stars in Kaluza-Klein gravity
de Leon, J Ponce
2010-01-01
In this work we examine the effective four-dimensional world that emanates from a general class of static spherical Ricci-flat solutions in Kaluza-Klein gravity in $D$-dimensions. By means of dimensional reduction we obtain a family of asymptotically flat Schwarzschild-like metrics for which all the components of the Ricci tensor, except for $R_{11}$, are zero. Although the reduced spacetime is not empty, it is similar to vacuum in the sense that the effective matter satisfies an equation of state which is the generalization of $(\\rho + 3p) = 0$ for "nongravitating matter" in 4D. In Kaluza-Klein gravity these Schwarzschild-like metrics describe the exterior of a spherical star without rotation. In this framework, we generalize the well-known Buchdahl's theorem for perfect fluid spheres whose mass density does not increase outward. Without any additional assumptions, we develop the most general expression for the compactness limit of a star. We provide some numerical values for it, which in principle are obser...
Cardoso, V; Yoshida, S; Cardoso, Vitor; Lemos, Jose' P.S.; Yoshida, Shijun
2003-01-01
We calculate the quasinormal modes (QNMs) for gravitational perturbations of the Schwarzschild black hole in the five dimensional (5D) spacetime with a continued fraction method. As shown by Kodama and Ishibashi, the gravitational perturbations of higher-dimensional (higher-D) Schwarzschild black holes can be divided into three decoupled classes, namely scalar-gravitational, vector-gravitational, and tensor-gravitational perturbations. In order to examine the QNMs, we make use of Schr\\"odinger-type wave equations for determining the dynamics of the gravitational perturbations. We apply the continued fraction method and expand the eigenfunctions around the black hole horizon in terms of Fr\\"obenius series. It is found that the resulting recurrence relations become an eight-term relation for the scalar-gravitational perturbations and four-term relations for the vector-gravitational and tensor-gravitational perturbations. For all the types of perturbations, the QNMs associated with $l=2$, $l=3$, and $l=4$ are ca...
Ghosh, Shubhrangshu; Banik, Prabir
2015-07-01
In this paper, we present a complete work on steady state spherically symmetric Bondi type accretion flow in the presence of cosmological constant (Λ) in both Schwarzschild-de Sitter (SDS) and Schwarzschild anti-de Sitter (SADS) backgrounds considering an isolated supermassive black hole (SMBH), with the inclusion of a simple radiative transfer scheme, in the pseudo-general relativistic paradigm. We do an extensive analysis on the transonic behavior of the Bondi type accretion flow onto the cosmological BHs including a complete analysis of the global parameter space and the stability of flow, and do a complete study of the global family of solutions for a generic polytropic flow. Bondi type accretion flow in SADS background renders multiplicity in its transonic behavior with inner "saddle" type and outer "center" type sonic points, with the transonic solutions forming closed loops or contours. There is always a limiting value for ∣Λ∣ up to which we obtain valid stationary transonic solutions, which correspond to both SDS and SADS geometries; this limiting value moderately increases with the increasing radiative efficiency of the flow, especially correspond to Bondi type accretion flow in SADS background. Repulsive Λ suppresses the Bondi accretion rate by an order of magnitude for relativistic Bondi type accretion flow for a certain range in temperature, and with a marginal increase in the Bondi accretion rate if the corresponding accretion flow occurs in SADS background. However, for a strongly radiative Bondi type accretion flow with high mass accretion rate, the presence of cosmological constant do not much influence the corresponding Bondi accretion rate of the flow. Our analysis show that the relic cosmological constant has a substantial effect on Bondi type accretion flow onto isolated SMBHs and their transonic solutions beyond length-scale of kiloparsecs, especially if the Bondi type accretion occurs onto the host supergiant ellipticals or central
Karl Marx, un periodista en la Era del Capital. Apuntes para una investigación
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Espinoza Pino, Mario
2014-06-01
Full Text Available The aim of this article is to criticize the traditional representation of Karl Marx’s journalistic works, usually forgotten by a misleading canon that assumes his articles only as a minor work. One of the problems of this traditional conception is that it dissociates his theoretical and economic contributions from the historical development of the author’s thought (and also from its material roots. We will try to point the importance of Karl Marx’s mature journalism in two areas: in the construction of the central concepts of his critic against the capitalist mode of production (surplus value, a multilineal historical perspective, a global description of the world market, etc. and in the production of political cartographies to intervene in the class conflict. This article poses several hypothesis and tentative affirmations about Karl Marx’s journalism that may serve as a point of departure for a critical research.El objetivo de este artículo es criticar la representación tradicional del trabajo periodístico de Karl Marx, habitualmente olvidado por un canon engañoso que sólo asume sus artículos al precio de convertirlos en una obra menor. Uno de los problemas de esta concepción tradicional es que disocia sus contribuciones teóricas y económicas del desarrollo histórico del pensamiento del autor (y también de sus raíces materiales. Intentaremos señalar la importancia del periodismo maduro de Karl Marx en dos áreas: en la construcción de los conceptos centrales de su crítica contra el capitalismo (plusvalor, un enfoque histórico multilineal, una descripción global del mercado mundial, etc. y en la producción de cartografías políticas para intervenir en el conflicto de clases. Este artículo plantea varias hipótesis y afirmaciones tentativas sobre el periodismo de Karl Marx que pueden servir como punto de partida de una investigación crítica.
Roosna-Alliku mõisa häärber / Karl Kolopka, Nele Rohtla, Johann Schultz
Kolopka, Karl
2004-01-01
12 ill.; peahoone ehitati Johann Schultzi kavandite järgi, siseinterjööri ilmestava Louis XVI stiilis stukitöö tegi Karl Kolopka, häärber restaureeriti Nele Rohtla (OÜ Mõisaprojekt) suunamisel
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Sergio Mendoza
2009-01-01
Full Text Available We present heuristic arguments suggesting that if EM waves with wavelengths somewhat larger than the Schwarzschild radius of a black hole were fully absorbed by it, the second law of thermodynamics would be violated, under the Bekenstein interpretation of the area of a black hole as a measure of its entropy. Thus, entropy considerations make the well known fact that large wavelengths are only marginally absorbed by black holes, a natural consequence of thermodynamics. We also study numerically the ingoing radial propagation of a scalar field wave in a Schwarzschild metric, relaxing the standard assumption which leads to the eikonal equation, that the wave has zero spatial extent. We find that if these waves have wavelengths larger that the Schwarzschild radius, they are very substantially reflected, fully to numerical accuracy. Interestingly, this critical wavelength approximately coincides with the one derived from entropy considerations of the EM field, and is consistent with well known limit results of scattering in the Schwarzschild metric. The propagation speed is also calculated and seen to differ from the value c, for wavelengths larger than Rs, in the vicinity of Rs. As in all classical wave phenomena, whenever the wavelength is larger or comparable to the physical size of elements in the system, in this case changes in the metric, the zero extent Ã¢Â€Â™particleÃ¢Â€Â™ description fails, and the wave nature becomes apparent.
Der Briefwechsel zwischen Alexander von Humboldt und Karl Ernst von Baer
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Thomas Schmuck
2012-10-01
Full Text Available Zusammenfassung Der kurze, nicht vollständig erhaltene Briefwechsel zwischen Alexander von Humboldt und Karl Ernst von Baer behandelt sehr verschiedene Themen: Politik, Kriegsgefahr, den Wissenschaftsbetrieb, Auszeichnungen und Tagungen, Embryologie und Cholera. Gemeinsam mit Briefen und Reden ergibt sich dabei ein differenziertes Bild der Beurteilung der beiden Wissenschaftler durch den jeweils anderen. Während Baer sich als Bewunderer Humboldts erweist, erscheint umgekehrt Humboldts Einschätzung Baers als ambivalent. Abstract The short, not completely preserved correspondence between Alexander von Humboldt and Karl Ernst von Baer deals with a wide range of subjects: politics and the danger of war, academic activities, scientific awards and conferences, aspects of embryology and the cholera. Letters to third persons and speeches, together with the correspondence between Humboldt and Baer show a differentiated pattern of mutual appraisal: While Baer always remained an admirer of the elder naturalist, Humboldt’s estimation was characterized by ambivalence.
The Potassium-Argon Laser Experiment (KArLE): In Situ Geochronology for Planetary Robotic Missions
Cohen, Barbara
2016-01-01
The Potassium (K) - Argon (Ar) Laser Experiment (KArLE) will make in situ noble-gas geochronology measurements aboard planetary robotic landers and roverss. Laser-Induced Breakdown Spectroscopy (LIBS) is used to measure the K abun-dance in a sample and to release its noble gases; the evolved Ar is measured by mass spectrometry (MS); and rela-tive K content is related to absolute Ar abundance by sample mass, determined by optical measurement of the ablated volume. KArLE measures a whole-rock K-Ar age to 10% or better for rocks 2 Ga or older, sufficient to resolve the absolute age of many planetary samples. The LIBS-MS approach is attractive because the analytical components have been flight proven, do not require further technical development, and provide complementary measurements as well as in situ geochronology.
Karl Menningu (ja iseenese) päästmiseks / Ants Hein
Hein, Ants, 1952-
2008-01-01
Vastuseks Karin Hallas-Murula arvustusele "Maja, mis on sümbol" (Sirp, 2007, 5. X, lk. 13) ja Mait Väljase arvustusele "Iseolemise algus arhitektuuris" (Maja, 2008, nr. 1, lk. 86-87) oma 2007. a. ilmunud raamatust "Maja kui sümbol : Eesti Üliõpilaste Seltsi hoone Tartus" kohta. Georg Hellati ja Karl Menningu osalusest EÜS-i hoone sünniloos. Frank Lloyd Wrightist kui võimalikust eeskujuandjast
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R. C. Misra
1971-04-01
Full Text Available Classical Karl Fischer method has been modified so as to make it suitable for determining free and dissolved water present in aviation fuels in excess of 10 ppm which is considered as limiting concentration value for safe fueling of aircrafts particularly in the arduous climatic conditions as encountered in military operations. The modified method employed a special ethylene glyccl solvent mixture and another water saturated fuel sample as blank.
Karl Menningu (ja iseenese) päästmiseks / Ants Hein
Hein, Ants, 1952-
2008-01-01
Vastuseks Karin Hallas-Murula arvustusele "Maja, mis on sümbol" (Sirp, 2007, 5. X, lk. 13) ja Mait Väljase arvustusele "Iseolemise algus arhitektuuris" (Maja, 2008, nr. 1, lk. 86-87) oma 2007. a. ilmunud raamatust "Maja kui sümbol : Eesti Üliõpilaste Seltsi hoone Tartus" kohta. Georg Hellati ja Karl Menningu osalusest EÜS-i hoone sünniloos. Frank Lloyd Wrightist kui võimalikust eeskujuandjast
Karl Popper: a propósito de La sociedad abierta y sus enemigos
Tobón Sanín , Gilberto
2016-01-01
Este texto pretende llevar a cabo una crítica al racionalismo extremo de Karl Popper, a veces rayano en el subjetivismo, pues racionalismo e irracionalismo en las sociedades son momentos de una totalidad más amplia de la realidad histórica, como quiera que la sociedad se mueve es por los conflictos y las contradicciones, y no por los consensos efímeros de las partes en conflicto.
Tim, Jan Lucas ja Karl Robert - vennad üheks kuuks / Maris Laurits
Laurits, Maris
2009-01-01
Rakvere Teatri suvelavastuse "Vennad Lõvisüdamed" kaks Karli osatäitjat Jan Lucas Videvik ja Tim Leesnurm ning Joonatani osatäitja Karl Robert Saaremäe tegid Loksal Kaldmaa talus ratsasõiduproove. Üllar Saaremäe lavastuse "Vennad Lõvisüdamed" (Astrid Lindgreni samanimelise jutustuse järgi) esietendus on 11. juunil Rakvere teatri taga aias
Den første Karl Gustav-krig 1657-58
DEFF Research Database (Denmark)
Olden-Jørgensen, Sebastian
2008-01-01
Artiklen diskuterer den første Karl Gustav-krig i forskellige persketiver og konkluderer, at krigen ikke bør opfattes som et dårligt forberedt og uigennemtænkt forsøg på dansk revanche inden for rammerne af en nordisk rivalisering, men snarere som en velovervejet satsning og et led i den dansk-s...
星井, 進介; Hoshii, Shinsuke
2011-01-01
In The Social Psychology of Organizing, 2nd edition, Karl E. Weiek described an organizing theory based on flows, changes, connections, interdependence, and social interaction. This paper examined the definition and process of organizing proposed by Weick. The process of organizing and how organization emerges in Weick's book are discussed. Organizing was defined by Weick as a consensually validated grammar for reducing equivoeality by means of sensible interlocked behaviors. Weick showed tha...
Tim, Jan Lucas ja Karl Robert - vennad üheks kuuks / Maris Laurits
Laurits, Maris
2009-01-01
Rakvere Teatri suvelavastuse "Vennad Lõvisüdamed" kaks Karli osatäitjat Jan Lucas Videvik ja Tim Leesnurm ning Joonatani osatäitja Karl Robert Saaremäe tegid Loksal Kaldmaa talus ratsasõiduproove. Üllar Saaremäe lavastuse "Vennad Lõvisüdamed" (Astrid Lindgreni samanimelise jutustuse järgi) esietendus on 11. juunil Rakvere teatri taga aias
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Julio Cesar Rodrigues Pereira
2010-12-01
Full Text Available This article discusses the main elements of the epistemology of human sciences of Karl Popper. It was organized as follows. First, we positioned ourselves in the Popper-Adorno controversy. Then weestablished the parameters of discussion, particularly in regards to the idea of “scientific explanation”. Some elements of Popper’s Theory of Knowledge are then analyzed. The final part discusses thescientific parameters of Social Sciences.Este artigo discute os principais elementos da epistemologia das ciências humanas de Karl Popper. Foi organizado como segue. Em primeiro lugar, nos posionamos sobre a polêmica Popper-Adorno. Então, nós estabelecemos os parâmetros de discussão, nomeadamente no que respeita a idéia de "explicação científica". A seguir são analisados alguns elementos da Teoria do Conhecimento de Popper. A parte final discute os parâmetros científicos de Ciências Sociais
Energy Technology Data Exchange (ETDEWEB)
Cziesielski, Erich [CRP Bauingenieure GmbH, Berlin (Germany)
2008-12-15
In his postdoctoral thesis Karl Gertis described the basic principles of the function and the geometric boundary conditions for the construction of ventilated external walls. The proposed revision of DIN 18516-1:2008-09 will again based on the fundamental results of his work. Meanwhile, further work has been carried out on various aspects, including the work by Janser and Marquardt on wind load assumptions and the corrosion-inhibiting effect of ventilated external walls. Ventilated external facings can be retrofitted to damaged walls in large-panel buildings to improve thermal insulation, as a remedial measure for joint defects, and in order to improve corrosion protection. This paper discusses the physical mechanisms relating to wind load reduction and corrosion protection. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Die grundlegende Arbeit ueber die Wirkungsweise und die geometrischen Randbedingungen bei der Konstruktion hinterluefteter Aussenwandkonstruktionen hat Karl Gertis mit seiner Habilitationsschrift verfasst. Auch in der geplanten Neufassung von DIN 18516-1:2008-09 wird auf die grundlegenden Ergebnisse seiner Arbeit unveraendert zugegriffen werden. Weiterfuehrende Arbeiten wurden unter anderem ueber die anzusetzenden Windlastannahmen und die korrosionshemmende Wirkung hinterluefteter Aussenwaende von Janser und Marquardt durchgefuehrt. Durch die nachtraegliche Montage von hinterluefteten Aussenwandkonstruktionen auf die geschaedigten Waende des Grosstafelbaus kann sowohl die Waermedaemmung verbessert werden als auch eine Sanierung der Fugen erfolgen; insbesondere wird aber durch das Aufbringen hinterluefteter Aussenwandkonstruktionen der Korrosionsschutz wesentlich verbessert. Im Folgenden werden die Wirkmechanismen hinsichtlich der Reduzierung der Windlast und des Korrosionsschutzes beschrieben. (Abstract Copyright [2008], Wiley Periodicals, Inc.)
Twee vroeë reaksies van Gereformeerde kant op Karl Barth
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B. J. Engelbrecht
1986-06-01
Full Text Available In 1919 het die eerste uitgawe van die epogmakende “Romerbrief” van Karl Barth verskyn. Van die tweede druk in 1922 sê hy dat “kein Stein mehr auf dem andem” gelaat is nie. So opspraakwekkend was hierdie boek dat in 1929 die 5de druk van die tweede, radikaal-hersiene uitgawe verskyn het. Intussen het nog ander werke van Barth en selfs oor Barth verskyn. 0ns noem o.a. sy Der Christ in der Gesellschaft (1920; Das Wort Gottes und die Theologie (1924; Vom Christlichen Leben (1926; Auferstehung der Toten (2. Aufl. 1927, sy preke saam met Eduard Thurneysen Komm Schopfer Geist, (Dritt Aufl., 7-9 Tausend(! 1926. Maar 1927 was veral belangrik vanweë die verskyning van Barth se eerste Dogmatiekboek: “Die Christliche Dogmatik im Entwurf. 1 Die Lehre vom Worte Gottes. Prolegomena zur Christlichen Dogmatik” . Voor dié datum het dwarsoor die wêreld, maar ook in Nederland wye reaksie op sy teologie ontstaan. In 1926 skryf Max Strauch sy “Theologie Karl Barth’s”, terwyl Haitjema in Nederland ook in 1926 sy Barth boek die lig laat sien (Prof. dr. Th. L. Haitjema, Karl Barth, Wageningen 1926. Ander Nederlanders wat gereageer het, was drr. A. H. de Hartog, V. Hepp, Ph. Kohnstamm en di. D. Tromp en 0. Noordmans.
Schwarzschild-Couder telescope for the Cherenkov Telescope Array: Development of the Optical System
Rousselle, Julien; Errando, Manel; Humensky, Brian; Mukherjee, Reshmi; Nieto, Daniel; Okumura, Akira; Vassiliev, Vladimir
2013-01-01
The CTA (Cherenkov Telescope Array) is the next generation ground-based experiment for very high-energy (VHE) gamma-ray observations. It will integrate several tens of imaging atmospheric Cherenkov telescopes (IACTs) with different apertures into a single astronomical instrument. The US part of the CTA collaboration has proposed and is developing a novel IACT design with a Schwarzschild-Couder (SC) aplanatic two mirror optical system. In comparison with the traditional single mirror Davies-Cotton IACT the SC telescope, by design, can accommodate a wide field-of-view, with significantly improved imaging resolution. In addition, the reduced plate scale of an SC telescope makes it compatible with highly integrated cameras assembled from silicon photo multipliers. In this submission we report on the status of the development of the SC optical system, which is part of the effort to construct a full-scale prototype telescope of this type at the Fred Lawrence Whipple Observatory in southern Arizona.
A comparative study of background flow geometries in Schwarzschild metric with shock
Tarafdar, Pratik
2016-01-01
We study the effects of discontinuity in general relativistic axially symmetric background fluid flow in the Schwarzschild metric. The discontinuities, or 'shocks', are incorporated using general relativistic Rankine-Hugoniot conditions. A general shock-invariant quantity is thus derived analytically for three distinct geometric configurations of the background fluid flow, viz., constant height discs, quasi-spherical discs and discs in hydrostatic equilibrium in the vertical direction. As already pointed out in our previous works, even identical initial conditions may lead to completely different phase-space behaviour of the stationary solutions for separate flow geometries. Hence it is then useful to investigate and compare the influence of geometric configuration of the flow described by various thermodynamic equations of state, on different important properties and manifestations of such physical discontinuities.
Coordinate Families for the Schwarzschild Geometry Based on Radial Timelike Geodesics
Finch, Tehani K.
2015-01-01
We explore the connections between various coordinate systems associated with observersmoving inwardly along radial geodesics in the Schwarzschild geometry. Painleve-Gullstrand (PG) time is adapted to freely falling observers dropped from rest from infinity; Lake-Martel-Poisson (LMP) time coordinates are adapted to observers who start at infinity with non-zero initial inward velocity; Gautreau-Hoffmann time coordinates are adapted to observers dropped from rest from a finite distance from the black hole horizon.We construct from these an LMP family and a proper-time family of time coordinates, the intersection of which is PG time. We demonstrate that these coordinate families are distinct, but related, one-parameter generalizations of PG time, and show linkage to Lemaître coordinates as well.
Accretion of a relativistic, collisionless kinetic gas into a Schwarzschild black hole
Rioseco, Paola
2016-01-01
We provide a systematic study for the accretion of a collisionless, relativistic kinetic gas into a nonrotating black hole. To this end, we first solve the relativistic Liouville equation on a Schwarzschild background spacetime. The most general solution for the distribution function is given in terms of appropriate symplectic coordinates on the cotangent bundle, and the associated observables, including the particle current density and stress energy-momentum tensor, are determined. Next, we explore the case where the flow is steady-state and spherically symmetric. Assuming that in the asymptotic region the gas is described by an equilibrium distribution function, we determine the relevant parameters of the accretion flow as a function of the particle density and the temperature of the gas at infinity. In particular, we find that in the low temperature limit the tangential pressure at the horizon is about an order of magnitude larger than the radial one, showing explicitly that a collisionless gas, despite ex...
El-Menoufi, Basem Kamal
2015-01-01
In the context of effective field theory, we consider quantum gravity with minimally coupled massless particles. Fixing the background geometry to be of the Kerr-Schild type, we fully determine the one-loop effective action of the theory whose finite non-local part is induced by the long-distance portion of quantum loops. This is accomplished using the non-local expansion of the heat kernel in addition to a non-linear completion technique through which the effective action is expanded in gravitational curvatures. Via Euclidean methods, we identify a logarithmic correction to the Bekenstein-Hawking entropy of Schwarzschild black hole. Using dimensional transmutation the result is shown to exhibit an interesting interplay between the UV and IR properties of quantum gravity.
Constraining the Schwarzschild-de Sitter Solution in Models of Modified Gravity
Iorio, Lorenzo; Radicella, Ninfa; Saridakis, Emmanuel N
2016-01-01
The Schwarzschild-de Sitter (SdS) solution exists in the large majority of modified gravity theories, as expected, and in particular the effective cosmological constant is determined by the specific parameters of the given theory. We explore the possibility to use future extended radio-tracking data from the currently ongoing New Horizons mission in the outskirts peripheries of the Solar System, at about 40 au, in order to constrain this effective cosmological constant, and thus to impose constrain on each scenario's parameters. We investigate some of the recently most studied modified gravities, namely $f(R)$ and $f(T)$ theories, dRGT massive gravity, and Ho\\v{r}ava-Lifshitz gravity, and we show that New Horizons mission may bring an improvement of one-two orders of magnitude with respect to the present bounds from planetary orbital dynamics.
Quasi-normal modes of Schwarzschild-de Sitter black holes
Zhidenko, A
2004-01-01
The low-laying frequencies of characteristic quasi-normal modes (QNM) of Schwarzschild-de Sitter (SdS) black holes have been calculated for fields of different spin using the 6th-order WKB approximation and the approximation by the P"{o}shl-Teller potential. The well-known asymptotic formula for large $l$ is generalized here on a case of the Schwarzchild-de Sitter black hole. In the limit of the near extreme $L$ term the results given by both methods are in a very good agreement, and in this limit fields of different spin decay with the same rate. In addition, the fact that the spectrum of massless Dirac quasi-normal frequencies is the same for opposite chyrality has been numerically proved for SdS background.
Weakly regular fluid flows with bounded variation on a Schwarzschild background
LeFloch, Philippe G
2015-01-01
We study the global dynamics of isothermal fluids evolving in the domain of outer communication of a Schwarzschild black hole. We first formulate the initial value problem within a class of weak solutions with bounded variation (BV), possibly containing shock waves. We then introduce a version of the random choice method and establish a global-in-time existence theory for the initial value problem within the proposed class of weakly regular fluid flows. The initial data may have arbitrary large bounded variation and can possibly blow up near the horizon of the black hole. Furthermore, we study the class of possibly discontinuous, equilibrium solutions and design a version of the random choice method in which these fluid equilibria are exactly preserved. This leads us to a nonlinear stability property for fluid equilibria under small perturbations with bounded variation. Furthermore, we can also encompass several limiting regimes (stiff matter, non-relativistic flows, extremal black hole) by letting the physic...
Harmsen, G E; Cho, H T; Cornell, A S
2016-01-01
In June 2015 the Large Hadron Collider was able to produce collisions with an energy of 13TeV, where collisions at these energy levels may allow for the formation of higher dimensional black holes. In order to detect these higher dimensional black holes we require an understanding of their emission spectra. One way of determining this is by looking at the absorption probabilities associated with the black hole. In this proceedings we will look at the absorption probability for spin-3/2 particles near $N$-dimensional Schwarzschild black holes. We will show how the Unruh method is used to determine these probabilities for low energy particles. We then use the Wentzel-Kramers-Brillouin approximation in order to determine these absorption probabilities for the entire possible energy range.
Non-existence of dynamical perturbations of Schwarzschild with vanishing self-dual part
Wald, R. M.
1986-01-01
A recent proposal of Ashtekar (1985) for the canonical quantisation of gravity involves a new choice of a (complex) polarisation on the (real) phase space of general relativity. In order for the 'four dimensional' version of Ashtekar's proposal to be viable, it is necessary that for an arbitrary (real) background solution there exist a sufficient number of (complex) solutions of the linearised Einstein equation with perturbed Weyl spinor having vanishing self-dual part. It is shown that this is not the case by explicitly demonstrating that for the Schwarzschild spacetime, aside from stationary perturbations, there are no such linearised solutions which can be expressed as superpositions of modes of real frequencies. The viability of the '3+1 version' of Ashtekar's proposal is not affected by these considerations.
The structure of the extreme Schwarzschild-de Sitter space-time
Podolsky, J
1999-01-01
The extreme Schwarzschild-de Sitter space-time is a spherically symmetric solution of Einstein's equations with a cosmological constant Lambda and mass parameter m>0 which is characterized by the condition that 9 Lambda m^2=1. The global structure of this space-time is here analyzed in detail. Conformal and embedding diagrams are constructed, and synchronous coordinates which are suitable for a discussion of the cosmic no-hair conjecture are presented. The permitted geodesic motions are also analyzed. By a careful investigation of the geodesics and the equations of geodesic deviation, it is shown that specific families of observers escape from falling into the singularity and approach nonsingular asymptotic regions which are represented by special "points" in the complete conformal diagram. The redshift of signals emitted by particles which fall into the singularity, as detected by those observers which escape, is also calculated.
One-loop effective potential of the Higgs field on the Schwarzschild background
Kazinski, P O
2009-01-01
A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. Some properties of this potential are investigated. In particular, it turns out that there exist only two possible scenarios depending on a sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases.
Two-oscillator Kantowski-Sachs model of the Schwarzschild black hole interior
Djordjevic, Goran S.; Nesic, Ljubisa; Radovancevic, Darko
2016-08-01
In this paper the interior of the Schwarzschild black hole, which is presented as a vacuum, homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model, is considered. Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model is presented in a classical, a p-adic and a noncommutative case. Then, within the standard quantum approach Wheeler-DeWitt equation and its general solutions, i.e. a wave function of the model is written, and then an adelic wave function is constructed. Finally, thermodynamics of the model is studied by using the Feynman-Hibbs procedure.
Cosmological isotropic matter-energy generalizations of Schwarzschild and Kerr metrics
Arik, Metin
2016-01-01
We present a time dependent isotropic fluid solution around a Schwarzschild black hole. We offer the solutions and discuss the effects on the field equations and the horizon. We derive the energy density, pressure and the equation of state parameter. In the second part, we generalize the rotating black hole solution to an expanding universe. We derive from the proposed metric the special solutions of the field equations for the dust approximation and the dark energy solution. We show that the presence of a rotating black hole does not modify the scale factor $b(t)=t^{2/3}$ law for dust, nor $b(t)=e^{\\lambda\\hspace{1mm}t}$ and $p=-\\rho$ for dark energy.
Mathisson-Papapetrou-Dixon equations in the Schwarzschild and Kerr backgrounds
Plyatsko, R. M.; Stefanyshyn, O. B.; Fenyk, M. T.
2011-10-01
A new representation, which does not contain the third-order derivatives of the coordinates, of the exact Mathisson-Papapetrou-Dixon equations, describing the motion of a spinning test particle, is obtained under the assumption of the Mathisson-Pirani condition in a Kerr background. For this purpose the integrals of energy and angular momentum of the spinning particle as well as a differential relationship following from the Mathisson-Papapetrou-Dixon equations are used. The form of these equations is adapted for their computer integration with the aim to investigate the influence of the spin-curvature interaction on the particle's behavior in the gravitational field without restrictions on its velocity and spin orientation. Some numerical examples for a Schwarzschild background are presented.
Mathisson-Papapetrou-Dixon equations in the Schwarzschild and Kerr backgrounds
Plyatsko, Roman; Fenyk, Mykola
2011-01-01
A new representation, which does not contain the third-order derivatives of the coordinates, of the exact Mathisson-Papapetrou-Dixon equations, describing the motion of a spinning test particle, is obtained under the assumption of the Mathisson-Pirani condition in a Kerr background. For this purpose the integrals of energy and angular momentum of the spinning particle as well as a differential relationship following from the Mathisson-Papapetrou-Dixon equations are used. The form of these equations is adapted for their computer integration with the aim to investigate the influence of the spin-curvature interaction on the particle's behavior in the gravitational field without restrictions on its velocity and spin orientation. Some numerical examples for a Schwarzschild background are presented.
Mathisson-Papapetrou-Dixon equations in the Schwarzschild and Kerr backgrounds
Energy Technology Data Exchange (ETDEWEB)
Plyatsko, R M; Stefanyshyn, O B; Fenyk, M T, E-mail: plyatsko@lms.lviv.ua [Pidstryhach Institute of Applied Problems in Mechanics and Mathematics, Ukrainian National Academy of Sciences, 3-b Naukova Str., Lviv, 79060 (Ukraine)
2011-10-07
A new representation, which does not contain the third-order derivatives of the coordinates, of the exact Mathisson-Papapetrou-Dixon equations, describing the motion of a spinning test particle, is obtained under the assumption of the Mathisson-Pirani condition in a Kerr background. For this purpose the integrals of energy and angular momentum of the spinning particle as well as a differential relationship following from the Mathisson-Papapetrou-Dixon equations are used. The form of these equations is adapted for their computer integration with the aim to investigate the influence of the spin-curvature interaction on the particle's behavior in the gravitational field without restrictions on its velocity and spin orientation. Some numerical examples for a Schwarzschild background are presented.
Schwarzschild-type solution in an effective gravitational theory with local Galilean invariance
Cuzinatto, R R; De Montigny, M; Khanna, F C
2009-01-01
We construct a Schwarzschild-type exact external solution for a theory of gravity admitting local Galilean invariance. In order to realize the Galilean invariance we need to adopt a five-dimensional manifold. The solution for the gravitational field equations obeys a Birkhoff-like theorem. Three classic tests of general relativity are analyzed in detail: the perihelion shift of the planet Mercury, the deflection of light by the Sun, and the gravitational redshift of atomic spectral lines. The Galilean version of these tests exhibits an additional parameter $b$ related to the fifth-coordinate. This constant $b$ can be estimated by a comparison with observational data. We observe that the Galilean theory is able to reproduce the results traditionally predicted by general relativity in the limit of negligible $b$. This shows that the tests are not specifically Lorentz invariant.
Towards a realization of Schwarzschild-(anti-)de Sitter spacetime as a particulate metamaterial
Mackay, Tom G
2011-01-01
While metamaterials offer the potential to realize Tamm mediums which represent vacuous spacetime subjected to gravitational fields, practical formulations for suitable metamaterials have not hitherto been developed. This matter is addressed by establishing a metamaterial formulation for the Tamm medium representing Schwarzschild-(anti-)de Sitter spacetime. Our formulation is remarkably simple and does not involve a complex nanostructure of the type that is often associated with metamaterials. Instead it is based on the homogenization of only isotropic dielectric and isotropic magnetic component mediums, which are distributed randomly as oriented spheroidal particles. Using the inverse Bruggeman homogenization formalism, we demonstrated that a wide range of constitutive parameter values for the Tamm medium may be accessed through varying the particle shape, volume fraction or relative permittivity and relative permeability of the component mediums. The presented formulation is appropriate for the regions of s...
Accretion model of a rotating gas sphere onto a Schwarzschild black hole
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S. Mendoza
2008-01-01
Full Text Available Construimos un modelo simple de acreción de una esfera de gas sin presión hacia un agujero negro de Schwarzschild. Lejos del agujero, el flujo rota como un cuerpo rígido. Mostramos como construir soluciones analíticas en términos de las funciones elípticas de Jacobi. Esta construcción representa la generalización relativista del modelo Newtoniano de acreción primeramente propuesto por Ulrich (1976. De la misma manera que, como ocurre en el caso Newtoniano, el flujo naturalmente predice la existencia de un disco de acreción ecuatorial rotando alrededor del agujero negro. Sin embargo, el radio del disco se incrementa de manera monotónica sin límite a medida que el flujo se acerca al máximo momento angular permitido por el modelo.
Gravitational vacuum polarization; 3, energy conditions in the (1+1) Schwarzschild spacetime
Visser, M
1996-01-01
Building on a pair of earlier papers, I investigate the various point-wise and averaged energy conditions for the quantum stress-energy tensor corresponding to a conformally-coupled massless scalar field in the in the (1+1)-dimensional Schwarzschild spacetime. Because the stress-energy tensors are analytically known, I can get exact results for the Hartle--Hawking, Boulware, and Unruh vacua. This exactly solvable model serves as a useful sanity check on my (3+1)-dimensional investigations wherein I had to resort to a mixture of analytic approximations and numerical techniques. Key results in (1+1) dimensions are: (1) NEC is satisfied outside the event horizon for the Hartle--Hawking vacuum, and violated for the Boulware and Unruh vacua. (2) DEC is violated everywhere in the spacetime (for any quantum state not just the standard vacuum states).
Could the real (not virtual) static observer exist outside a Schwarzschild black hole?
Berezin, Victor
2011-01-01
The aim of this Letter is rather pedagogical. We considered the static spherically symmetric ensemble of observers, having finite bare mass and trying to measure geometrical and physical properties of the environmental static (Schwarzschild) space-time. It is shown that, using the photon rockets (which the mass together with the mass of their fuel is also taken into account) they can managed to keep themselves on the fixed value of radius. The process of diminishing the total bare mass up to zero lasts infinitely long time. It is important that the problem is solved self-consistently, i.e., with full account for the back reaction of both bare mass and radiation from rockets on the space-time geometry.
Two-oscillator Kantowski-Sachs model of the Schwarzschild black hole interior
Djordjevic, Goran S; Radovancevic, Darko
2015-01-01
In this paper the interior of the Schwarzschild black hole, which is presented as a vacuum homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model, is considered. Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model will be presented in a classical, a p-adic and a noncommutative case. Then, within the standard quantum approach Wheeler-DeWitt equation and its general solutions, i.e. a wave function of the model, will be written, and then an adelic wave function will be constructed. Finally, thermodynamics of the model will be studied by using the Feynman-Hibbs procedure.
Scalar field as a Bose-Einstein condensate in a Schwarzschild-de Sitter spacetime
Castellanos, Elías; Lämmerzahl, Claus; Macías, Alfredo
2015-01-01
In this paper we analyze some properties of a scalar field configuration, where it is considered a trapped Bose-Einstein condensate in a Schwarzschild-de Sitter background spacetime. In a natural way, the geometry of the curved spacetime provides an effective trapping potential for the scalar field configuration. This fact allows to explore some thermodynamical properties of the system. Additionally, the curved geometry of the spacetime also induces a position dependent self-interaction parameter, that can be interpreted as a kind of \\emph{gravitational Feshbach resonance}, which could affect the stability of the \\emph{cloud} and could be used to obtain information about the interactions among the components of the system.
On geometry of deformed black holes: II. Schwarzschild hole surrounded by a Bach-Weyl ring
Basovník, M
2016-01-01
We continue to study the response of black-hole space-times on the presence of additional strong sources of gravity. Restricting ourselves to static and axially symmetric (electro-)vacuum exact solutions of Einstein's equations, we first considered the Majumdar--Papapetrou solution for a binary of extreme black holes in a previous paper, while here we deal with a Schwarzschild black hole surrounded by a concentric thin ring described by the Bach--Weyl solution. The geometry is again revealed on the simplest invariants determined by the metric (lapse function) and its gradient (gravitational acceleration), and by curvature (Kretschmann scalar). Extending the metric inside the black hole along null geodesics tangent to the horizon, we mainly focus on the black-hole interior (specifically, on its sections at constant Killing time) where the quantities behave in a way indicating a surprisingly strong influence of the external source. Being already distinct on the level of potential and acceleration, this is still...
Rigorous construction and Hadamard property of the Unruh state in Schwarzschild spacetime
Energy Technology Data Exchange (ETDEWEB)
Dappiaggi, Claudio; Pinamonti, Nicola [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Moretti, Valter [Trento Univ., Povo (Italy). Dipt. di Matematica; Istituto Nazionale di Fisica Nucleare, Povo (Italy); Istituto Nazionale di Alta Matematica ' ' F. Severi' ' , GNFM, Sesto Fiorentino (Italy)
2009-07-15
The discovery of the radiation properties of black holes prompted the search for a natural candidate quantum ground state for a massless scalar field theory on Schwarzschild spacetime, here considered in the Eddington-Finkelstein representation. Among the several available proposals in the literature, an important physical role is played by the so-called Unruh state which is supposed to be appropriate to capture the physics of a black hole formed by spherically symmetric collapsing matter. Within this respect, we shall consider a massless Klein-Gordon field and we shall rigorously and globally construct such state, that is on the algebra of Weyl observables localised in the union of the static external region, the future event horizon and the non-static black hole region. Eventually, out of a careful use of microlocal techniques, we prove that the built state fulfils, where defined, the so-called Hadamard condition; hence, it is perturbatively stable, in other words realizing the natural candidate with which one could study purely quantum phenomena such as the role of the back reaction of Hawking's radiation. From a geometrical point of view, we shall make a profitable use of a bulk-to-boundary reconstruction technique which carefully exploits the Killing horizon structure as well as the conformal asymptotic behaviour of the underlying background. From an analytical point of view, our tools will range from Hoermander's theorem on propagation of singularities, results on the role of passive states, and a detailed use of the recently discovered peeling behaviour of the solutions of the wave equation in Schwarzschild spacetime. (orig.)
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Sergio Schneider
2011-08-01
Full Text Available O ensaio aborda a importância da redescoberta do pensamento de Karl Polanyi e de sua crítica à "sociedade de mercado" na retomada dos estudos e debates sobre o desenvolvimento (rural. Após uma apresentação geral do quadro teórico e analítico de Polanyi, buscamos utilizar seus conceitos para interpretar a dinâmica da mercantilização dos meios de vida e das formas sociais de trabalho e produção no espaço rural, bem como dos sistemas agroalimentares no capitalismo contemporâneo. Com base nestas proposições, refletimos sobre o papel dos atores sociais e das instituições nos processos de mudança social em geral e os de desenvolvimento rural em particular. Finalizamos, propondo algumas potencialidades dessa abordagem para os estudos sobre desenvolvimento rural no Brasil.The essay deals with the importance of the rediscovery of Karl Polanyi's thinking and of his criticism of the "market society" in resuming (rural development studies and debates. Following an overall presentation of Polanyi's theoretical and analytical framework, we look for using his concepts to interpret the commoditization dynamics of the rural livelihoods and the social forms of labor and production in the rural space, as well as the commoditization of the agri-food systems in the contemporary capitalism. Based on these statements, we reflect about the role of social actors and institutions in the processes of social change at large and of rural development in particular. And, finally, we propose some potentialities of this approach for the rural development studies in Brazil.
Wang, Zhi-Yong; Qiu, Qi; Wang, Yun-Xiang; Shi, Shuang-Jin
2016-01-01
The (1, 0)+(0, 1) representation of the group SL(2, C) provides a six-component spinor equivalent to the electromagnetic field tensor. By means of the (1, 0)+(0, 1) description, one can treat the photon field in curved spacetime via spin connection and the tetrad formalism, which is of great advantage to study the gravitational spin-orbit coupling of photons. Once the gravitational spin-orbit coupling is taken into account, the traditional radius of the circular photon orbit in the Schwarzschild geometry should be replaced with two different radiuses corresponding to the photons with the helicities of +1 and -1, respectively. Owing to the splitting of energy levels induced by the spin-orbit coupling, photons (from Hawking radiations, say) escaping from a Schwarzschild black hole are partially polarized, provided that their initial velocities possess nonzero tangential components.
Lin, Kai
2016-01-01
In this work, we study the quasinormal modes of Schwarzschild and Schwarzschild (Anti-) de Sitter black holes by a matrix method. The proposed method involves discretizing the master field equation and expressing it in form of a homogeneous system of linear algebraic equations. The resulting homogeneous matrix equation furnishes a non-standard eigenvalue problem, which can then be solved numerically to obtain the quasinormal frequencies. A key feature of the present approach is that the discretization of the wave function and its derivatives is made to be independent of any specific metric through coordinate transformation. In most cases, it can be carried out beforehand which in turn improves the efficiency and facilitates the numerical implementation. We also analyze the precision and efficiency of the present method as well as compare the results to those obtained by different approaches.
A dynamical system's approach to Schwarzschild null geodesics
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Belbruno, Edward [Courant Institute of Mathematical Sciences, New York University, NY (United States); Pretorius, Frans, E-mail: belbruno@Princeton.edu, E-mail: fpretori@Princeton.edu [Department of Physics, Princeton University, Princeton, NJ (United States)
2011-10-07
The null geodesics of a Schwarzschild black hole are studied from a dynamical system's perspective. Written in terms of Kerr-Schild coordinates, the null geodesic equation takes on the simple form of a particle moving under the influence of a Newtonian central force with an inverse-cubic potential. We apply a McGehee transformation to these equations, which clearly elucidates the full phase space of solutions. All the null geodesics belong to one of the four families of invariant manifolds and their limiting cases, further characterized by the angular momentum L of the orbit: for |L| > |L{sub c}|, (1) the set that flow outward from the white hole, turn around, and then fall into the black hole, (2) the set that fall inward from past null infinity, turn around outside the black hole to continue to future null infinity, and for |L| < |L{sub c}|, (3) the set that flow outward from the white hole and continue to future null infinity and (4) the set that flow inward from past null infinity and into the black hole. The critical angular momentum L{sub c} corresponds to the unstable circular orbit at r = 3M, and the homoclinic orbits associated with it. There are two additional critical points of the flow at the singularity at r = 0. Though the solutions of geodesic motion and Hamiltonian flow we describe here are well known, what we believe is that a novel aspect of this work is the mapping between the two equivalent descriptions, and the different insights each approach can give to the problem. For example, the McGehee picture points to a particularly interesting limiting case of the class (1) that move from the white to black hole: in the L {yields} {infinity} limit, as described in Schwarzschild coordinates, these geodesics begin at r = 0, flow along t = constant lines, turn around at r = 2M, and then continue to r = 0. During this motion they circle in azimuth exactly once, and complete the journey in zero affine time.
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Melnikov, Kirill
2002-08-08
We develop a Hamiltonian formalism which can be used to discuss the physics of a massless scalar field in a gravitational background of a Schwarzschild black hole. Using this formalism we show that the time evolution of the system is unitary and yet all known results such as the existence of Hawking radiation can be readily understood. We then point out that the Hamiltonian formalism leads to interesting observations about black hole entropy and the information paradox.
Rodeghiero, G.; Giro, E.; Canestrari, R.; Pernechele, C.; Sironi, G.; Pareschi, G.; Lessio, L.; Conconi, P.
2016-05-01
Dual-mirror Schwarzschild-Couder (SC) telescopes are based on highly aspherical optics, and they represent a novel design in the world of very high energy astrophysics. This work addresses the realization and the qualification of the secondary mirror for an SC telescope, named ASTRI, developed in the context of the Cherenkov Telescope Array Observatory. The discussion surveys the overall development from the early design concept to the final acceptance optical tests.
El huracán Karl: concepciones sobre su origen en una comunidad de Veracruz
Arturo Marinero Heredia; María José García Oramas
2015-01-01
Se analizan las concepciones e ideas de pobladores adultos sobre las afectaciones sufridas por el huracán Karl en 2010, en el municipio de La Antigua, Veracruz. Los datos se obtuvieron de entrevistas a informantes claves y grupos focales, además de la revisión de notas periodisticas. Se observa que las concepciones e ideas sobre el origen del desastre las adjudican a las fuerzas naturales, espirituales o religiosas sin reconocer la responsabilidad de las autoridades encargadas de elaborar pol...
El huracán Karl: concepciones sobre su origen en una comunidad de Veracruz
Arturo Marinero Heredia; María José García Oramas
2015-01-01
Se analizan las concepciones e ideas de pobladores adultos sobre las afectaciones sufridas por el huracán Karl en 2010, en el municipio de La Antigua, Veracruz. Los datos se obtuvieron de entrevistas a informantes claves y grupos focales, además de la revisión de notas periodisticas. Se observa que las concepciones e ideas sobre el origen del desastre las adjudican a las fuerzas naturales, espirituales o religiosas sin reconocer la responsabilidad de las autoridades encargadas de elaborar pol...
Karl R. Popper'ın Tarihsicilik Eleştirisi
Rıza Bakış; Eyüp Alsancak
2016-01-01
ABSTRACT: Karl R. Popper is an important philosopher of science of 20th Century and is known in this field through his theory of falsification. But the critical theory of rationality is indeed his basic theory and it can be seen in his whole idea. Critique of historicism also contains his views on the social and political philosophy in a systematic context in relation to them. Popper embodied his views about the historicism through human-centered thoughts of philosophers such as Plato, Arist...
REALISMO E PLURALISMO: A FILOSOFIA DA CIÊNCIA DE KARL R. POPPER
Mateus Romanini
2012-01-01
O presente trabalho tem por objetivo principal apresentar uma interpretação da obra de Karl Raimund Popper que leva em consideração dois problemas e suas respectivas soluções propostas pelo autor. Primeiramente buscar-se-á tratar do problema que emerge do debate sobre que entidades podem ser consideradas reais, a saber, se e como entidades abstratas interagem com o mundo físico. Popper não aceita as posições monistas e dualistas porque ambas levam ao determinismo. Assim, para r...
Karl Jaspers' phenomenology in the light of histological and X-ray metaphors.
Vlasova, Olga Alexandrovna; Beveridge, Allan
2014-03-01
The study considers the origins of Karl Jaspers' phenomenology. What did phenomenology mean to Jaspers and what was his personal perspective? What metaphors did he associate with it? This paper describes his phenomenological method by using the metaphors of histology and the X-ray. This perspective enables a better understanding, not only of the origins and essence of his phenomenology but also of its value for Jaspers himself. In Jaspers' daily life, he would have been familiar with microscopes and X-ray machines.
A interpretação do Proslogion por Karl Barth
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Paulo Ricardo Martines
1996-12-01
Full Text Available O objetivo principal deste texto é apresentai alguns elementos essenciais da interpretação do Proslogion feita por Karl Barth em seu livro S. Anselme, Fides Quaerens Intellectum. La preuve de l'existence de Dieu (trad. franc. Com Base no "programa teológico" de Anselmo, Barth identifica as linhas fundamentais para a leitura dos capítulos 2 a 4 do Pioslogion. Tentaremos mostrar a significação e o alcance dessa interpretação para a historiografia do pensamento anselmiano.
Karl Gustaf Torsten Sjögren and Sjögren-Larsson syndrome
2011-01-01
Karl Gustaf Torsten Sjögren (1896-1974) a Swedish psychiatrist and geneticist, was a pioneer of modern Swedish psychiatry. Sjögren studied medicine at the University of Uppsala. From 1932 to 1935, he was Head Physician and Director of Lillehagen Hospital in Gothenburg, and between 1935- 1945, he was physician-in-chief at the psychiatric department of Sahlgrenska Hospital in Gothenburg. Sjögren was professor of psychiatry at Karolinska Institutet from 1945 to 1961 and was elected to the Royal...
Karl Barth’s role in church and politics from 1930 to 1935
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André J. Groenewald
2007-05-01
Full Text Available Karl Barth saw in natural theology a threat to the church of Christ. He was convinced that the so-called “German Christians” under the influence of the National Socialist Party practised natural theology. He advocated the need for the church of Christ to be church according to the Word of God. The church can be true church of Christ when it listens to and obeys the true calling of God. Barth’s critique of an exclusive “Volkskirche” can serve as a corrective for the definition of the Nederduitsch Hervormde Kerk as a “volkskerk”.
Karl Marx e a Essência Autogestionária da Comuna de Paris
Nildo Viana
2011-01-01
O artigo apresenta a interpretação da Comuna de Paris por Karl Marx como autogoverno dos produtores, autogestão social. Uma análise minuciosa do capítulo da obra “A Guerra Civil na França” fornece os elementos interpretativos para compreender a pe...
Francisco de Paula Castro e Karl von den Steinen: expedicion?rios do Xingu (1884)
Ara?jo, Marcos Paulo Mendes
2015-01-01
No final do s?culo XIX, um significativo n?mero de pesquisadores estrangeiros esteve no Brasil a fim de realizar viagens explorat?rias. Um desses exploradores foi Karl von den Steinen que esteve no Brasil em duas oportunidades, sendo a primeira em 1884 quando visitou a regi?o do Xingu na companhia de outros dois alem?es, v?rios militares brasileiros e guias contratados. Esta pesquisa apresenta o resultado da leitura e an?lise do relat?rio de viagem produzido pelo capit?o de infantaria do Ex?r...
Relativistic spine jets from Schwarzschild black holes: "Application to AGN radioloud sources"
Meliani, Z; Tsinganos, K; Trussoni, E; Cayatte, V
2010-01-01
The two types of Fanaroff-Riley radio loud galaxies, FRI and FRII, exhibit strong jets but with different properties. These differences may be associated to the central engine and/or the external medium. Aims: The AGN classification FRI and FRII can be linked to the rate of electromagnetic Poynting flux extraction from the inner corona of the central engine by the jet. The collimation results from the distribution of the total electromagnetic energy across the jet, as compared to the corresponding distribution of the thermal and gravitational energies. We use exact solutions of the fully relativistic magnetohydrodynamical (GRMHD) equations obtained by a nonlinear separation of the variables to study outflows from a Schwarzschild black hole corona. A strong correlation is found between the jet features and the energetic distribution of the plasma of the inner corona which may be related to the efficiency of the magnetic rotator. It is shown that observations of FRI and FRII jets may be partially constrained by...
Geometry of deformed black holes. II. Schwarzschild hole surrounded by a Bach-Weyl ring
Basovník, M.; Semerák, O.
2016-08-01
We continue to study the response of black-hole space-times on the presence of additional strong sources of gravity. Restricting ourselves to static and axially symmetric (electro)vacuum exact solutions of Einstein's equations, we first considered the Majumdar-Papapetrou solution for a binary of extreme black holes in a previous paper, while here we deal with a Schwarzschild black hole surrounded by a concentric thin ring described by the Bach-Weyl solution. The geometry is again revealed on the simplest invariants determined by the metric (lapse function) and its gradient (gravitational acceleration), and by curvature (Kretschmann scalar). Extending the metric inside the black hole along null geodesics tangent to the horizon, we mainly focus on the black-hole interior (specifically, on its sections at constant Killing time) where the quantities behave in a way indicating a surprisingly strong influence of the external source. Being already distinct on the level of potential and acceleration, this is still more pronounced on the level of curvature: for a sufficiently massive and/or nearby (small) ring, the Kretschmann scalar even becomes negative in certain toroidal regions mostly touching the horizon from inside. Such regions have been interpreted as those where magnetic-type curvature dominates, but here we deal with space-times which do not involve rotation and the negative value is achieved due to the electric-type components of the Riemann/Weyl tensor. The Kretschmann scalar also shapes rather nontrivial landscapes outside the horizon.
Transformation Groups for a Schwarzschild-Type Geometry in f(R Gravity
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Emre Dil
2016-01-01
Full Text Available We know that the Lorentz transformations are special relativistic coordinate transformations between inertial frames. What happens if we would like to find the coordinate transformations between noninertial reference frames? Noninertial frames are known to be accelerated frames with respect to an inertial frame. Therefore these should be considered in the framework of general relativity or its modified versions. We assume that the inertial frames are flat space-times and noninertial frames are curved space-times; then we investigate the deformation and coordinate transformation groups between a flat space-time and a curved space-time which is curved by a Schwarzschild-type black hole, in the framework of f(R gravity. We firstly study the deformation transformation groups by relating the metrics of the flat and curved space-times in spherical coordinates; after the deformation transformations we concentrate on the coordinate transformations. Later on, we investigate the same deformation and coordinate transformations in Cartesian coordinates. Finally we obtain two different sets of transformation groups for the spherical and Cartesian coordinates.
Lambda does not Lens: Deflection of Light in the Schwarzschild-de Sitter Spacetime
Butcher, Luke M
2016-01-01
Debate persists as to whether the cosmological constant can directly modify the power of a gravitational lens. With the aim of re-establishing a consensus on this issue, I conduct a comprehensive analysis of gravitational lensing in the Schwarzschild-de Sitter spacetime. The effective lensing law is found to be in precise agreement with the $\\Lambda=0$ result: $\\alpha_\\mathrm{eff} = 4m/b_\\mathrm{eff}+15\\pi m^2/4b_\\mathrm{eff}^2 +O(m^3/b_\\mathrm{eff}^3)$, where the effective bending angle $\\alpha_\\mathrm{eff}$ and impact parameter $b_\\mathrm{eff}$ are defined by the angles and angular diameter distances measured by a comoving cosmological observer. The effective lensing law can be derived using lensed or unlensed angular diameter distances, although the inherent ambiguity of unlensed distances generates an additional uncertainty $O(m^5/\\Lambda b_\\mathrm{eff}^7)$. I conclude that the cosmological constant does not interfere with the standard gravitational lensing formalism.
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...
Thermodynamics of the Schwarzschild-AdS Black Hole with a Minimal Length
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Yan-Gang Miao
2017-01-01
Full Text Available Using the mass-smeared scheme of black holes, we study the thermodynamics of black holes. Two interesting models are considered. One is the self-regular Schwarzschild-AdS black hole whose mass density is given by the analogue to probability densities of quantum hydrogen atoms. The other model is the same black hole but whose mass density is chosen to be a rational fractional function of radial coordinates. Both mass densities are in fact analytic expressions of the δ-function. We analyze the phase structures of the two models by investigating the heat capacity at constant pressure and the Gibbs free energy in an isothermal-isobaric ensemble. Both models fail to decay into the pure thermal radiation even with the positive Gibbs free energy due to the existence of a minimal length. Furthermore, we extend our analysis to a general mass-smeared form that is also associated with the δ-function and indicate the similar thermodynamic properties for various possible mass-smeared forms based on the δ-function.
Partial wave analysis of the Dirac fermions scattered from Schwarzschild black holes
Energy Technology Data Exchange (ETDEWEB)
Cotaescu, Ion I.; Crucean, Cosmin; Sporea, Ciprian A. [West University of Timisoara, Timisoara (Romania)
2016-03-15
Asymptotic analytic solutions of the Dirac equation, giving the scattering modes (of the continuous energy spectrum, E > mc{sup 2}) in Schwarzschild's chart and Cartesian gauge, are used for building the partial wave analysis of Dirac fermions scattered by black holes. In this framework, the analytic expressions of the differential cross section and induced polarization degree are derived in terms of scattering angle, mass of the black hole, and energy and mass of the fermion. Moreover, the closed form of the absorption cross section due to the scattering modes is derived showing that in the high-energy limit this tends to the event horizon area regardless of the fermion mass (including zero). A graphical study presents the differential cross section analyzing the forward/backward scattering (known also as glory scattering) and the polarization degree as functions of scattering angle. The graphical analysis shows the presence of oscillations in scattering intensity around forward/backward directions, phenomena known as spiral scattering. The energy dependence of the differential cross section is also established by using analytical and graphical methods. (orig.)
On the paradox of Hawking radiation in a maximally extended Schwarzschild solution
Ellis, George F R
2013-01-01
This paper considers the effect of Hawking radiation on an eternal black hole - that is. a maximally extended Schwarzschild solution. Symmetry considerations that hold independent of the details of the emission mechanism show there is an inconsistency in the claim that such a blackhole evaporates away in a finite time. In essence: because the external domain is static, there is an infinite time available for the process to take place, so whenever the evaporation process is claimed to come to completion, it should have happened earlier. The problem is identified to lie in the claim that the locus of emission of Hawking radiation lies just outside the globally defined event horizon. Rather, the emission domain must be mainly located inside the event horizon, so most of the Hawking radiation ends up at this singularity rather than at infinity and the black hole never evaporates away. This result supports a previous claim [arXiv:1310.4771] that astrophysical black holes do not evaporate.
Highly eccentric inspirals into a Schwarzschild black hole using self-force calculations
Osburn, Thomas; Warburton, Niels; Evans, Charles
2016-03-01
Eccentric-orbit inspirals into a massive black hole are calculated using the gravitational self-force. Both extreme-mass-ratio inspirals (EMRIs) and intermediate-mass-ratio inspirals (IMRIs) are modeled. These calculations include all dissipative and conservative first-order-in-the-mass-ratio effects for inspirals into a Schwarzschild black hole. We compute systems with initial eccentricities as high as e = 0.8 and initial separations as large as 100 M. In the case of EMRIs, the calculations follow the decay through many thousands of orbits up to the onset of the plunge. Inspirals are computed using an osculating-orbits scheme that is driven by self-force data from a hybridized self-force code. A Lorenz gauge self-force code is combined with highly accurate flux data from a Regge-Wheeler-Zerilli code, allowing the hybrid self-force model to track orbital phase in the inspirals to within 0.1 radians or better. Extensions of the method to include other physical effects are considered.
Interior volumes of extremal and ($1+D$) dimensional Schwarzschild black holes
Bhaumik, Nilanjandev
2016-01-01
It has already been shown for the Reissner-Nordstr{\\"o}m and Kerr black holes that the maximum interior volume enclosed by the event horizon ceases to zero in the extremal limit. We show here that if we start with an extremal black hole at the beginning, corresponding volume is non-zero. Interestingly, both for the extremal Reissner-Nordstr{\\"o}m and Kerr, this value comes out to be equal to one quarter of the horizon area, which is the entropy of the black hole. Next the same quantity is calculated for the ($1+D$)-dimensional Schwarzschild case. Taking into account the mass change due to Hawking radiation, we show that the volume increases towards the end of the evaporation. This fact is not new as it has been observed earlier for four dimensional case. The interesting point we observe is that this increase rate decreases towards the higher value of space dimensions $D$; i.e. it is a decelerated expansion of volume with the increase of spacial dimensions. This implies that for a sufficiently large $D$, the m...
Gravitational self-force on a particle in eccentric orbit around a Schwarzschild black hole
Barack, Leor
2010-01-01
We present a numerical code for calculating the local gravitational self-force acting on a pointlike particle in a generic (bound) geodesic orbit around a Schwarzschild black hole. The calculation is carried out in the Lorenz gauge: For a given geodesic orbit, we decompose the Lorenz-gauge metric perturbation equations (sourced by the delta-function particle) into tensorial harmonics, and solve for each harmonic using numerical evolution in the time domain (in 1+1 dimensions). The physical self-force along the orbit is then obtained via mode-sum regularization. The total self-force contains a dissipative piece as well as a conservative piece, and we describe a simple method for disentangling these two pieces in a time-domain framework. The dissipative component is responsible for the loss of orbital energy and angular momentum through gravitational radiation; as a test of our code we demonstrate that the work done by the dissipative component of the computed force is precisely balanced by the asymptotic fluxe...
Schwarzschild microscopes in vacuum ultraviolet and soft X-ray regions
Institute of Scientific and Technical Information of China (English)
M. WATANABE; M. YANAGIHARA; T. EJIMA; M. TOYODA; Y. KONDO; T. HATANO; T. TSURU; M. YAMAMOTO
2005-01-01
Microscopes in vacuum ultraviolet and soft X-ray regions using a normal incidence type of Schwarzschild objective are reviewed. The objective consists ofa concave mirror and a convex mirror coated with a high reflectance multilayer, having a large numerical aperture comparing with other objectives. The microscopes have been used to diagnose inertia-confinement-fusion plasmas, and to investigate small samples or microstructures of inorganic and organic materials by imaging them using laboratory light sources. Synchrotron radiation has been also used to obtain a microbeam for a photoelectron scanning microscope with a spatial resolution of 0.1 μm. The structure and performance of two laboratory microscopes developed at Tohoku University are demonstrated. One of them is a soft X-ray emission imaging microscope. An image of an artificial pattern made of W and SiO2 on Si wafer by focusing Si L emission was presented. The other is an ultraviolet photoelectron scanning microscope using a He (helium) gas discharge lamp. The valence band spectra of a microcrystal of FeWO4 were presented. Furthermore other applications such as demagnifying optics for lithography and optics to gather fluorescence for emission spectroscopy are introduced.
Development of a mid-sized Schwarzschild-Couder Telescope for the Cherenkov Telescope Array
Energy Technology Data Exchange (ETDEWEB)
Cameron, Robert A.
2012-06-28
The Cherenkov Telescope Array (CTA) is a ground-based observatory for very high-energy (10 GeV to 100 TeV) gamma rays, planned for operation starting in 2018. It will be an array of dozens of optical telescopes, known as Atmospheric Cherenkov Telescopes (ACTs), of 8 m to 24 m diameter, deployed over an area of more than 1 square km, to detect flashes of Cherenkov light from showers initiated in the Earth's atmosphere by gamma rays. CTA will have improved angular resolution, a wider energy range, larger fields of view and an order of magnitude improvement in sensitivity over current ACT arrays such as H.E.S.S., MAGIC and VERITAS. Several institutions have proposed a research and development program to eventually contribute 36 medium-sized telescopes (9 m to 12 m diameter) to CTA to enhance and optimize its science performance. The program aims to construct a prototype of an innovative, Schwarzschild-Couder telescope (SCT) design that will allow much smaller and less expensive cameras and much larger fields of view than conventional Davies-Cotton designs, and will also include design and testing of camera electronics for the necessary advances in performance, reliability and cost. We report on the progress of the mid-sized SCT development program.
Radiative processes of two entangled atoms outside a Schwarzschild black hole
Menezes, G.
2016-11-01
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 a quantum electromagnetic field prepared in one of the usual vacuum states, namely, the Boulware, Unruh, or 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 the 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 that the thermal nature of the Hartle-Hawking and Unruh vacuum state allows the atoms to get entangled even if they were initially prepared in the separable ground state.
Merlin, Cesar
2014-01-01
We present a first numerical implementation of a new scheme by Pound et al. that enables the calculation of the gravitational self-force in Kerr spacetime from a reconstructed metric-perturbation in a radiation gauge. The numerical task of the metric reconstruction essentially reduces to solving the fully separable Teukolsky equation, rather than having to tackle the linearized Einstein's equations themselves. The method offers significant computational saving compared to existing methods in the Lorenz gauge, and we expect it to become a main workhorse for precision self-force calculations in the future. Here we implement the method for circular orbits on a Schwarzschild background, in order to illustrate its efficacy and accuracy. We use two independent methods for solving the Teukolsky equation, one based on a direct numerical integration, and the other on the analytical approach of Mano, Suzuki, and Takasugi. The relative accuracy of the output self-force is at least $10^{-7}$ using the first method, and a...
Holographic entanglement entropies for Schwarzschild and Reisner-Nordstr\\"om spacetimes
Sun, Yuan
2016-01-01
The holographic entanglement entropies (HEE) associated with four dimensional Schwarzschild and Reisner-Nordstr\\"om spacetimes are investigated. Unlike the cases of asymptotically AdS spacetimes for which the boundaries are always taken at (timelike) conformal infinities, we take the boundaries at either large but finite radial coordinate (far boundary) or very close to the black hole event horizons (near horizon boundary). The reason for such choices is that such boundaries are similar to the conformal infinity of AdS spacetime in that they are all timelike, so that there may be some hope to define dual systems with ordinary time evolution on such boundaries. Our results indicate that, in the case of far boundaries, the leading order contribution to the HEEs come from the background Minkowski spacetime, however, the next to leading order contribution which arises from the presence of the black holes is always proportional to the black hole mass, which constitutes a version of the first law of the HEE for asy...
Thermodynamics of the Schwarzschild-AdS black hole with a minimal length
Miao, Yan-Gang
2016-01-01
Using the mass-smeared scheme of black holes, we study the thermodynamics of black holes. Two interesting models are considered. One is the self-regular Schwarzschild-AdS black hole whose mass density is given by the analogue to probability densities of quantum hydrogen atoms. The other model is the same black hole but whose mass density is chosen to be a rational fractional function of radial coordinates. Both mass densities are in fact analytic expressions of the ${\\delta}$-function. We analyze the phase structures of the two models by investigating the heat capacity at constant pressure and the Gibbs free energy in an isothermal-isobaric ensemble. Both models fail to decay into the pure thermal radiation even with the positive Gibbs free energy due to the existence of a minimal length. Furthermore, we extend our analysis to a general mass-smeared form that is also associated with the ${\\delta}$-function, and indicate the similar thermodynamic properties for various possible mass-smeared forms based on the ...
Chaudhury, S; Das, T K; Chaudhury, Soumini; Ray, Arnab K.; Das, Tapas Kumar
2006-01-01
For inviscid, rotational accretion flows, both isothermal and polytropic, a simple dynamical systems analysis of the critical points has given a very accurate mathematical scheme to understand the nature of these points, for {\\em any} pseudo-potential by which the flow may be driven on to a Schwarzschild black hole. This allows for a complete classification of the critical points for a wide range of flow parameters, and shows that the only possible critical points for this kind of flow are saddle points and centre-type points. A restrictive upper bound on the angular momentum of critical solutions has been established. A time-dependent perturbative study reveals that the form of the perturbation equation, for both isothermal and polytropic flows, is invariant under the choice of any particular pseudo-potential. Under generically true outer boundary conditions, the inviscid flow has been shown to be stable under an adiabatic and radially propagating perturbtion. The perturbation equation has also served the du...
On pointwise decay of linear waves on a Schwarzschild black hole background
Donninger, Roland; Soffer, Avy
2009-01-01
We prove sharp pointwise $t^{-3}$ decay for scalar linear perturbations of a Schwarzschild black hole without symmetry assumptions on the data. We also consider electromagnetic and gravitational perturbations for which we obtain decay rates $t^{-4}$, and $t^{-6}$, respectively. We proceed by decomposition into angular momentum $\\ell$ and summation of the decay estimates on the Regge-Wheeler equation for fixed $\\ell$. We encounter a dichotomy: the decay law in time is entirely determined by the asymptotic behavior of the Regge-Wheeler potential in the far field, whereas the growth of the constants in $\\ell$ is determined entirely by the behavior of the Regge-Wheeler potential in a small neighborhood around the photon sphere. In other words, the tails are controlled by small energies, whereas the number of angular derivatives needed on the data is determined by energies close to the top of the Regge-Wheeler potential. This dichotomy corresponds to the well-known principle that for initial times the decay reflec...
Further Evidence for the Conformal Structure of a Schwarzschild Black Hole in an Algebraic Approach
Sen-Gupta, K; Gupta, Kumar S.; Sen, Siddhartha
2002-01-01
We study the excitations of a massive Schwarzschild black hole of mass M resulting from the capture of infalling matter described by a massless scalar field. The near-horizon dynamics of this system is governed by a Hamiltonian which is related to the Virasoro algebra and admits a one-parameter family of self-adjoint extensions described by a parameter z \\in R . The density of states of the black hole can be expressed equivalently in terms of z or M, leading to a consistent relation between these two parameters. The corresponding black hole entropy is obtained as S = S(0) - 3/2 log S(0) + C, where S(0) is the Bekenstein-Hawking entropy, C is a constant with other subleading corrections exponentially suppressed. The appearance of this precise form of the black hole entropy within our formalism, which is expected on general grounds in any conformal field theoretic description, provides strong evidence for the near-horizon conformal structure in this system.
Gravitational field of a Schwarzschild black hole and a rotating mass ring
Sano, Yasumichi
2014-01-01
The linear perturbation of the Kerr black hole has been discussed by using the Newman--Penrose and the perturbed Weyl scalars, $\\psi_0$ and $\\psi_4$ can be obtained from the Teukolsky equation. In order to obtain the other Weyl scalars and the perturbed metric, a formalism was proposed by Chrzanowski and by Cohen and Kegeles (CCK) to construct these quantities in a radiation gauge via the Hertz potential. As a simple example of the construction of the perturbed gravitational field with this formalism, we consider the gravitational field produced by a rotating circular ring around a Schwarzschild black hole. In the CCK method, the metric is constructed in a radiation gauge via the Hertz potential, which is obtained from the solution of the Teukolsky equation. Since the solutions $\\psi_0$ and $\\psi_4$ of the Teukolsky equations are spin-2 quantities, the Hertz potential is determined up to its monopole and dipole modes. Without these lower modes, the constructed metric and Newman--Penrose Weyl scalars have unph...
Globally regular solutions of a Schwarzschild black hole and a Reissner-Nordstrom black hole
Energy Technology Data Exchange (ETDEWEB)
Shen, W.; Zhu, S.
1985-08-01
A new physical concept about globally regular solutions is suggested. The globally regular solutions corresponding to the Schwarzchild black hole and the Reissner-Nordstrom black hole are examined. The space-time metric is singularity free except for trivial coordinate singularities. Features of the metric bear some analogy with the strong interaction. The equations of state of the matter inside the Schwarzschild and the Reissner-Nordstrom black holes have the form P = -rho, where rho is the density of the matter and is independent of the carried charge; since this equation of state describes an assembly of mesons being in the relativistic dense state, does this imply that the black hole is filled with mesons. The concept of globally regular solutions does not satisfy the strong energy condition given by Hawking and Ellis (1973) and so the singularity-free behavior at r = 0 does not violate Penrose's pioneering theorem on singularities (1965). It is thought that the concept of globally regular solutions suggested will be essential to describe the geometrical and physical properties of a body and a black hole. 10 references.
Second Order Quasi-Normal Mode of the Schwarzschild Black Hole
Nakano, Hiroyuki
2007-01-01
We formulate and calculate the second order quasi-normal modes (QNMs) of a Schwarzschild black hole (BH). Gravitational wave (GW) from a distorted BH, so called ringdown, is well understood as QNMs in general relativity. Since QNMs from binary BH mergers will be detected with high signal-to-noise ratio by GW detectors, it is also possible to detect the second perturbative order of QNMs, generated by nonlinear gravitational interaction near the BH. In the BH perturbation approach, we derive the master Zerilli equation for the metric perturbation to second order and explicitly regularize it at the horizon and spatial infinity. We numerically solve the second order Zerilli equation by implementing the modified Leaver's continued fraction method. The second order QNM frequencies are found to be twice the first order ones, and the GW amplitude is up to $\\sim 10%$ that of the first order for the binary BH mergers. Since the second order QNMs always exist, we can use their detections (i) to test the nonlinearity of ...
Miller, M Coleman
2014-01-01
We have developed sophisticated new Bayesian analysis methods that enable us to estimate quickly the masses and radii of rapidly rotating, oblate neutron stars using the energy-resolved waveforms of their X-ray burst oscillations and to determine the uncertainties in these mass and radius estimates. We demonstrate these methods by generating and analyzing the energy-resolved burst oscillation waveforms that would be produced by a hot spot on various rapidly rotating, oblate stars, using the analytic implementation of the oblate-star Schwarzschild-spacetime (OS) approximation introduced by Morsink et al. 2007. In generating these synthetic data, we assume that 10$^6$ counts have been collected from the hot spot and that the background is $9\\times10^6$ counts. This produces a realistic modulation amplitude and a total number of counts comparable to the number that could be obtained by future space missions, by combining data from many bursts from a given star. We compute the joint posterior distribution of the ...
Numerical Simulation of Rotating Accretion Disk Around the Schwarzschild Black Hole Using GRH Code
Donmez, O
2006-01-01
The 2D time dependent solution of thin accretion disk in a close binary system have been presented on the equatorial plane around the Schwarzschild black hole. To do that, the special part of the General Relativistic Hydrodynamical(GRH) equations are solved using High Resolution Shock Capturing (HRSC) schemes. The spiral shock waves on the accretion disk are modeled using perfect fluid equation of state with adiabatic indices $\\gamma = 1.05, 1.2$ and 5/3. The results show that the spiral shock waves are created for gammas except the case $\\gamma=5/3$. These results consistent with results from Newtonian hydrodynamic code except close to black hole. Newtonian approximation does not give good solution while matter closes to black hole. Our simulations illustrate that the spiral shock waves are created close to black hole and the location of inner radius of spiral shock wave is around $10M$ and it depends on the specific heat rates. We also find that the smaller $\\gamma$ is the more tightly the spiral winds.
Gravastars with an Interior Dark Energy Fluid and an Exterior de Sitter-Schwarzschild Spacetime
Brandt, C F C; da Silva, M F A; Rocha, P
2010-01-01
Dynamical models of prototype gravastars made of anisotropic dark energy are constructed, in which an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\\gamma)\\sigma$ divides the whole spacetime into two regions, the internal region filled with a dark energy (or phantom) fluid, and the external de Sitter-Schwarzschild region. It is found that in some cases the models represent the "bounded excursion" stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes or normal stars. An interesting result is that we can have black hole and stable gravastar formation even with an interior and a shell constituted of dark and repulsive dark energy. Besides, in one case we have a dynamical evolution to a black hole (for $\\Lambda=0$) or to a naked singularity (for $\\Lambda > 0$). This is the first time in the literature that a naked singularity emerges from a gravastar model.
Greybody factors for Schwarzschild black holes: Path-ordered exponentials and product integrals
Gray, Finnian
2015-01-01
In recent work concerning the sparsity of the Hawking flux [arXiv:1506.03975v2], we found it necessary to re-examine what is known regarding the greybody factors of black holes, with a view to extending and expanding on some old results from the 1970s. Focussing specifically on Schwarzschild black holes, we re-calculated and re-assessed the greybody factors using a path-ordered-exponential approach, a technique which has the virtue of providing a semi-explicit formula for the relevant Bogoliubov coefficients. These path-ordered-exponentials, (being based on a "transfer matrix" formalism), are closely related to so-called "product integrals", leading to quite straightforward and direct numerical evaluation, while avoiding any need for numerically solving differential equations. Furthermore, while considerable analytic information is already available regarding both the high-frequency and low-frequency asymptotics of these greybody factors, numerical approaches seem better adapted to finding suitable "global mo...
The psychology of thinking, animal psychology, and the young Karl Popper.
Ter Hark, Michel
2004-01-01
In the 1920s, Karl Popper wrote two large manuscripts on psychology that he never published. In his autobiography, Unended Quest, he attempts to reduce the importance of his work in psychology as much as possible, and in his philosophical work he is an antipsychologist. However, in this article, it is argued that Popper's early psychology has been pivotally important for the development of his philosophy. In particular, it is shown that Popper's views on psychology underwent a radical shift, one that paved the way for his characteristic deductive stance in philosophy. Popper's views shifted from an inductive and associationistic psychology toward a noninductive psychology of problem solving. Tracing the historical background of Popper's early work reveals how he integrated various parts of the psychology of Karl Groos into his analysis of the childish phenomenon of dogmatic thinking and how he shortly after appropriated various elements of the animal psychology of Hans Volkelt and Herbert Jennings in his biological approach to (dogmatic) thinking. In the monumental works of Otto Selz, however, Popper finally found the roots of a noninductive and biological approach to the growth of individual and scientific knowledge.
Karl Popper’s model under the perspective of the applied social sciences
Directory of Open Access Journals (Sweden)
Milton de Abreu Campanario
2012-04-01
Full Text Available DOI: http://dx.doi.org/10.5007/2175-8077.2012v14n32p124Karl Popper is the leading philosopher of science in modern times, competing with Thomas Kuhn’s interpretation to the primacy of how to utilize de scientific method. Clearly, there are different versions for a reading of this important author who coined the method called deductive with test. This text recognizes the relevance of Karl Popper’s view of science as a practice in hard and biological fields, where it is widely accepted. However, this popularity is not shared in the applied social sciences area. This is an essay to rescue his contribution in an attempt to translate the concepts he developed in a didactic way. To this end, there will be an introduction to the fundamentals of science as specific form o knowledge, seeking to contrast the deductive and inductive approaches and procedures of what is known as formal science, basic and applied. An attempt to classify the formulation of theoretical propositions is undertaken with the use of different criteria, taking examples in the field of management and economics as an illustration.
A crítica da epistemologia na sociologia do conhecimento de Karl Mannheim
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Luís de Gusmão
2011-04-01
Full Text Available O artigo analisa a crítica da epistemologia normativa na obra de Karl Mannheim, sublinhando a sua presença tanto na fase mais filosófica, associada ao elogio do historicismo, como na Sociologia do Conhecimento posterior. Chama a atenção também para a atualidade dessa crítica: ao censurar os epistemólogos do seu tempo por não levarem na devida conta os achados das ciências empíricas particulares, Mannheim antecipa, em décadas, tendências mais recentes da Sociologia do Conhecimento e da reflexão epistemológica.The article analyzes the critique of normative epistemology in the work of Karl Mannheim, stressing its presence both in his more philosophical phase, associated with the praise of historicism, and in his later Sociology of Knowledge. It also calls attention to the relevance of this critique: attacking the epistemologists of his time by not taking into proper account the findings of particular empirical sciences, Mannheim anticipated by decades recent trends in the Sociology of Knowledge and epistemological reflection.
La memoria, el tiempo y la historia en Karl Mannheim y en Maurice Halbwachs
Directory of Open Access Journals (Sweden)
Gérard NAMER
2009-03-01
Full Text Available RESUMEN: Las aportaciones de Maurice Halbwachs sobre la sociología de la memoria son suficientemente conocidas. Los análisis de Karl Mannheim añaden nuevos enfoques a los estudios sobre la sociología de la memoria y sus conceptos. Este artículo trata de comparar las aportaciones sociológicas de ambos, y cómo ellos renuevan, uno y otro sin conocerse, la concepción del tiempo, de la memoria y de la historia.ABSTRACT: The contributions of Maurice Halbwachs in regard to the sociology of memory are sufficiently well known. The analyses of Karl Mannheim add new approaches to the studies on the sociology of memory and its concepts. The objective of this article is to compare the sociological contributions of both to the study of memory in the period between the wars. Keywords: Sociology of knowledge, sociology of memory, individual memory, collective memory, social frameworks of memory, diverse memories, time, diverse social times, history, cultural history, conservative thought, totalitarianism.
Directory of Open Access Journals (Sweden)
Irene Fantappie
2012-04-01
Full Text Available It is not possible to understand Karl Kraus, claims Walter Benjamin, without assuming that in the oeuvre of the Viennese writer "everything takes place in the sphere of law". In Kraus’s thought legal issues are strongly related to literature and language. His concept of law stems from a higher ideal of ‘justice’; justice is based on language and language has a strong ideal and prescriptive value. Through the use of quotation Kraus charges literature and journalism with betraying language, while on the other hand he charges law with betraying justice. This essay aims at demonstrating trough an interdisciplinary approach that Kraus did not only involve law issues in his literary writings, he also invested some literary works – especially Shakespeare’s plays – with a legal value. In Kraus’s thought Shakespeare is a symbol of consubstantiality between reality and literature, and an 'encyclopedia' providing eternally valid categories. As an ideal paradigm for the interpretation of reality, Shakespeare is the utopian background of Kraus’s reflection on language and justice, bearing witness to the indissolubility, in Kraus’s thought, of literature and law. È impossibile comprendere alcunché di Karl Kraus, afferma Walter Benjamin, se non si capisce che nell’opera del grande scrittore viennese «tutto ha luogo nella sfera del diritto». In Kraus l’analisi delle questioni giuridiche è inscindibile dalla riflessione sulla letteratura e sul linguaggio. La disamina del diritto muove da un più alto ideale di giustizia fondato sulla lingua, e specularmente il linguaggio possiede una forte valenza ideale e prescrittivo-normativa. Attraverso l’uso della citazione Kraus mette sotto accusa letteratura e giornalismo in nome di un più alto ideale di lingua, mentre nei suoi scritti letterari mette sotto accusa il sistema del diritto in nome di un più alto ideale di giustizia. Scopo del presente saggio è dimostrare, utilizzando un
One-loop effective potential of the Higgs field on the Schwarzschild background
Kazinski, P. O.
2009-12-01
A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. It is shown that the obtained potential is generally covariant, depends on the space point through the metric component g00 in the adapted coordinates, and has the same form for an arbitrary static, spherically symmetric background. Some properties of this potential are investigated. In particular, if the conformal symmetry holds valid for massless particles on the given background, there exist only two possible scenarios depending on the sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely, when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. If the conformal symmetry is spoiled, an additional term in the effective potential appears and the intermediate regime arises. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases. It should be mentioned that the use of the one-loop approximation becomes questionable in the region where the one-loop effective potential acquires large values. So, in that region, we can believe in the obtained results only to a certain extent.
THE INNERMOST COLLIMATION STRUCTURE OF THE M87 JET DOWN TO ∼10 SCHWARZSCHILD RADII
Energy Technology Data Exchange (ETDEWEB)
Hada, Kazuhiro; Giroletti, Marcello; Giovannini, Gabriele [INAF Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Kino, Motoki; Doi, Akihiro [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara 252-5210 (Japan); Nagai, Hiroshi; Honma, Mareki; Hagiwara, Yoshiaki; Kawaguchi, Noriyuki [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
2013-09-20
We investigated the detailed inner jet structure of M87 using Very Long Baseline Array data at 2, 5, 8.4, 15, 23.8, 43, and 86 GHz, especially focusing on the multi-frequency properties of the radio core at the jet base. First, we measured the size of the core region transverse to the jet axis, defined as W{sub c}, at each frequency ν, and found a relation between W{sub c} and ν: W{sub c}(ν)∝ν{sup –0.71±0.05}. Then, by combining W{sub c}(ν) and the frequency dependence of the core position r{sub c}(ν), which was obtained in our previous study, we constructed a collimation profile of the innermost jet W{sub c}(r) down to ∼10 Schwarzschild radii (R{sub s}) from the central black hole. We found that W{sub c}(r) smoothly connects with the width profile of the outer edge-brightened, parabolic jet and then follows a similar radial dependence down to several tens of R{sub s}. Closer to the black hole, the measured radial profile suggests a possible change in the jet collimation shape from the outer parabolic one, where the jet shape tends to become more radially oriented. This result could be related to a magnetic collimation process or/and interactions with surrounding materials at the jet base. The present results shed light on the importance of higher-sensitivity/resolution imaging studies of M87 at 86, 43, and 22 GHz; these studies should be examined more rigorously.
Kruusimägi, Toomas, 1962-
2010-01-01
Uuest rahvusvahelisest International Baccalaureate'i (IB) õppekavast ja selle rakendamisest Tallinna Inglise Kolledži 11. klassis alates möödunud aastast räägivad kooli direktor Toomas Kruusimägi, õppedirektor Anu Parts ning õpilane Karl Hendrik Thomson
In a study of comparability of total water contents (%) of conditioned cottons by Karl Fischer Titration (KFT) and Low Temperature Distillation (LTD) reference methods, we demonstrated a match of averaged results based on a large number of replications and weighing the test specimens at the same tim...
Naised käsu korras firmade juhatusse! Jah või ei? / Kairi Alt, Aveli Kippari, Karl Koort... [jt.
2011-01-01
Küsimusele vastavad Columbus IT Partner Eesti AS personalijuht Kairi Alt, Stele ja Riveli omanik Aveli Kippari, AS Panaviatic'i turundusjuht Karl Koort, OÜ Tarkvara Tehnoloogia Arenduskeskuse tegevjuht Indrek Vainu, AS PricewaterhouseCoopers auditiosakonna direktor Eva Jansen, Kalev Chocolate Factory tootmisjuht Hardo Reinike
Blank ja Jeron (sero.org) / Joachim Blank, Karl Heinz Jeron ; interv. Tilman Baumgärtel
Blank, Joachim
2006-01-01
Nime sero.org all esinenud saksa kunstnikepaarist Joachim Blankist (sünd. 1963) ja Karl Heinz Jeronist ning nende loomingust, intervjuu kunstnikega nende Berliini ateljees 10. II 2000. Saksa võrgukunsti edendamisest rühmituste Lux Logis, Handshake ja Internationale Stadt koosseisus, jututubadest, teostest "Dump your trash", "Re-M@il", installatsioonidest "re: represent", "Scanner +++", "sign.post" ja muust
Blank ja Jeron (sero.org) / Joachim Blank, Karl Heinz Jeron ; interv. Tilman Baumgärtel
Blank, Joachim
2006-01-01
Nime sero.org all esinenud saksa kunstnikepaarist Joachim Blankist (sünd. 1963) ja Karl Heinz Jeronist ning nende loomingust, intervjuu kunstnikega nende Berliini ateljees 10. II 2000. Saksa võrgukunsti edendamisest rühmituste Lux Logis, Handshake ja Internationale Stadt koosseisus, jututubadest, teostest "Dump your trash", "Re-M@il", installatsioonidest "re: represent", "Scanner +++", "sign.post" ja muust
Mapping a Space of Biography: Karl Triebold and the Waldschule of Senne I-Bielefeld (c.1923-1939)
Thyssen, Geert
2012-01-01
Starting from a "life geography" of Karl Triebold, a leading figure in open-air education, this article provides an understanding of the seemingly ordinary but still idiosyncratic development of a German open-air school. Triebold's life's work, the fight against tuberculosis, conceived as character education through healthy occupation,…
Naised käsu korras firmade juhatusse! Jah või ei? / Kairi Alt, Aveli Kippari, Karl Koort... [jt.
2011-01-01
Küsimusele vastavad Columbus IT Partner Eesti AS personalijuht Kairi Alt, Stele ja Riveli omanik Aveli Kippari, AS Panaviatic'i turundusjuht Karl Koort, OÜ Tarkvara Tehnoloogia Arenduskeskuse tegevjuht Indrek Vainu, AS PricewaterhouseCoopers auditiosakonna direktor Eva Jansen, Kalev Chocolate Factory tootmisjuht Hardo Reinike
El huracán Karl: concepciones sobre su origen en una comunidad de Veracruz
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Arturo Marinero Heredia
2015-01-01
Full Text Available Se analizan las concepciones e ideas de pobladores adultos sobre las afectaciones sufridas por el huracán Karl en 2010, en el municipio de La Antigua, Veracruz. Los datos se obtuvieron de entrevistas a informantes claves y grupos focales, además de la revisión de notas periodísticas. Se observa que las concepciones e ideas sobre el origen del desastre las adjudican a las fuerzas naturales, espirituales o religiosas sin reconocer la responsabilidad de las autoridades encargadas de elaborar políticas públicas en la materia y en la falta de previsión social y personal frente a sus devastadores efectos. Esta concepción dificulta la prevención, mantiene a la comunidad en situación de vulnerabilidad e impide o imposibilita la integración, la cohesión social y la acción colectiva.
Cybernetics and Social Order. Models and Images of Society in Norbert Wiener and Karl Deutsch
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Roberto Carradore
2013-07-01
Full Text Available The present contribution aims at defining the relation between cybernetics and social theory from the perspective of society as order. After an historical framework of the cybernetic movement, a careful reading of the works of Norbert Wiener, in which he introduced the concept of feed-back and the idea of information society, has revealed a keen awareness about the social effects of technological innovation. Among the social scientists who had made use of cybernetic concepts, it has been considered the work of Karl Deutsch, which was one of the first completely cybernetic perspective for the study of political and social phenomena. The main conclusion is that cybernetics, as a meeting point between different disciplines, has produced an image of self-regulated society in line with the image of society as order.
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Spartaco Pupo
2016-07-01
Full Text Available The correspondence of 1948 between Karl Popper and Michael Oakeshott, translated for the first time in Italian and published in the appendix to this paper, demonstrates the existence of two different ways of thinking about politics: the rationalist approach, founded on the “argumentation” as a rational means for the non-violent solution of problems (Popper, and the traditionalist mode, inspired by the method of “conversation” as a guarantee of constant openness to the diversity of identities (Oakeshott. To rise from the letters is a mutual influence on the interpretation of the key concepts that characterize the thought of the two authors, which however does not cancel the fundamental divergence of their political orientation.
["Homesickness and crime"--a contribution of Karl Jaspers to criminal psychology].
Bachhiesl, Sonja Maria
2009-01-01
Even a century after its first publication in "Archives of Criminology" (in German: Archiv für Kriminologie), the doctoral thesis of Karl Jaspers (1883-1969), which was newly edited in 1996, continues to be of interest. Although the crimes described by Jaspers, which took place in a rural area, do no longer occur in this form just as the rural culture itself has disappeared, this paper nevertheless contains reflections that may also be relevant for the interpretation of modern potentials of conflict and violence and crimes rooted therein. The former homesickness has developed into novel phenomena of uprooting. In both cases, problems of maladjustment are a contributing factor to crime motivation. Thus despite all terminological and methodological change, Jaspers' thesis is an example for the continuing relevance of certain subjects in criminological discourse.
Investigation of amine-buffered amide reagents for coulometric Karl Fischer titration.
Larsson, William; Cedergren, Anders
2009-06-15
Formamide (FA), N-methylformamide (NMF), and dimethylformamide (DMF), were evaluated as solvents for coulometric Karl Fischer (KF) reagents in combination with several amine bases. Except for the effect of the iodine species (iodine or triiodide), the pH of the reagent and the position of the sulfur dioxide/hydrogen sulfite equilibrium were found to be the main factors explaining the large difference in the observed reaction rates between water and the KF reagent in these solvents. Acid-base titrations showed that hydrogen sulfite is the main sulfur reactant in these media. The results will be of great importance in finding suitable combinations of base and solvent with respect to stoichiometry, side reactions caused by active carbonyl compounds, and reagent stability.
Cedergren, A
1974-06-01
A new approach to the determination of water via the Karl Fischer reaction is described. Iodine is coulometrically generated and the end-point corresponding to a slight excess of iodine, is detected potentiometrically with a non-polarized platinum electrode. Samples of 1-500 mul containing 0.05-200 mug of water were analysed with a standard deviation of 0.015 mug in the range 0.05-20 mug of H(2)O. A specially constructed electrolysis cell was used in combination with an LKB 16300 Coulometric Analyzer and the time for a complete analysis was 1-4 min, depending on sample size. The reagent composition has been optimized in order to enhance the rate of the main reaction and to minimize the extent of side-reactions. Decreasing the temperature reduced the extent of side-reactions. The displacement of end-point potential on dilution was studied and a correction is discussed.
Karl Popper: La explicación en la disciplina histórica
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Holbein Giraldo-Paredes
2013-01-01
Full Text Available En el siguiente artículo se revisan los argumentos enunciados en la obra La miseria del historicismo, en la cual Karl Popper realiza una crítica a la concepción historicista emanada de la filosofía de autores como Platón, Hegel y Marx. Crítica que realiza aludiendo a argumentos de orden epistemológico, para demostrar que el modelo nomológico deductivo de la explicación no aplica a la disciplina histórica, y en este sentido negando una de las tesis más fuertes que él había defendido toda su vida: la del monismo metodológico o unificacionismo metodológico de la ciencia, heredada del positivismo lógico.
Hurricanes Karl and Tropical Storm Matthew Structure Observed by HIWRAP During GRIP
Heymsfield, G. M.; Guimond, S. R.; Tian, L.
2012-12-01
The dual-wavelength (Ku and Ka band) High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) flew for the first time on the Global Hawk during the 2010 Genesis and Rapid Intensification Processes (GRIP). HIWRAP is conical scanning and Doppler, and winds and reflectivity can be mapped within the swath below the Global Hawk. Two interesting cases from the HIWRAP flights were the rapid intensification of Hurricane Karl and the intensification of Tropical Storm Matthew. This presentation will highlight the precipitation and wind structure of these storms during their intensification as derived from the HIWRAP observations. If time permits and if available, highlights from HIWRAP observations from the Hurricane Severe Storm Sentinel (HS3) field campaign in September 2012 will be presented.
Karl Deutsch y su contribución al estudio de las Relaciones Internacionales
Sánchez Sánchez, Rafael
2011-01-01
Este artículo presenta una reseña, y no intenta ser más que eso, de la vida y obra del cientista político Karl Deutsch. Así, presenta aspectos biográficos de la vida de Deutsch. Su extraordinaria y muy activa vida académica. Sus análisis y aportes a las ciencias políticas y las Relaciones Internacionales, poniendo el énfasis en las críticas que hace al realismo político y en su contribución teórica y metodológica al estudio de la integración regional.
Historical consciousness and existential awareness in Karl Barth’s hermeneutics
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G.M.M. Pelser
2007-05-01
Full Text Available Karl Barth’s hermeneutic legacy prolonged Western Christian tradition, especially influenced by Hegelian philosophy of history. This led to Barth’s “theological exegesis” instead of a historic-critical exegesis. In a preceding article Barth’s understanding of the notion “hermeneutic circle” is discussed against the background of the Enlightenment and its counter-movement in Romanticism. In this article Barth’s attitude to the place and role of historical criticism is explained in light of his dialectic distinction between “scientific” and “practical” interpretation. The article aims to show that Barth, with his dialectics, continues Schleiermacher’s realism. In conclusion, the positivistic traits in the Barth legacy are raised once again, in order to open the door to Jürgen Habermas and other deconstructionist thinkers of the postmodern era in hermeneutics.
Karl ernst von Baer's 'Uber Entwickelungsgeschichte der Thiere II' and its unpublished drawings.
Tammiksaar, Erki; Brauckmann, Sabine
2004-01-01
In 1828 Karl Ernst von Baer (1792-1876) published his seminal Uber Entwickelungsgeschichte der Thiere. Beobachtung und Reflexion. In the preface he announced that a second volume with one copper plate would be finished 'in a few weeks'. However, it took nine years until the unfinished second volume was released, with four copperplates. In his 'Autobiography', von Baer did not clarify the reasons why he did not finish his research program of comparative embryology. The paper attempts to elucidate them, furnished by archival documents and von Baer's unpublished embryological drawings. Our sketch of a few figures will show that (1) von Baer searched for 'analogies' (homologies) as a unifying principle and (2) explained the mechanisms of embryogenesis by physiological reasoning (electromagnetism). The main objective is to show that technical problems in illustrating and conceptual difficulties impeded von Baer's ambitious research program.
FILSAFAT ILMU KARL R. POPPER DAN THOMAS S. KUHN SERTA IMPLIKASINYA DALAM PENGAJARAN ILMU
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Slamet Subekti
2016-04-01
Full Text Available This article discusses about philosophy of science according to Karl R. Popper and Thomas S. Kuhn. There are similarities and differences between their views about how progress and what function of science.Apparently both Popper and Kuhn agree that science does not proceed by induction. However Kuhn disagrees with the view that science progresses by falsifiability through conjectures and refutations, but occurance by paradigm shift. Popper and Kuhn’s disagreement amounted to a distinction between two functions within the practice of science, one of criticism (Popper and one of puzzle solving (Kuhn.Science education implies the teaching and learning of science interesting and fruitful in one hand, and teachers should be role models to students in the other hand
Karl Marx e a Essência Autogestionária da Comuna de Paris
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Nildo Viana
2011-03-01
Full Text Available
O artigo apresenta a interpretação da Comuna de Paris por Karl Marx como autogoverno dos produtores, autogestão social. Uma análise minuciosa do capítulo da obra “A Guerra Civil na França” fornece os elementos interpretativos para compreender a percepção da Comuna de Paris como obra autogestionários dos operários parisienses, o que foi um elemento fundamental para o desenvolvimento do marxismo posterior.
Vital forces and organization: philosophy of nature and biology in Karl Friedrich Kielmeyer.
Gambarotto, Andrea
2014-12-01
The historical literature on German life science at the end of the 18th century has tried to rehabilitate eighteenth century vitalism by stressing its difference from Naturphilosophie. Focusing on the work of Karl Friedrich Kielmeyer this paper argues that these positions are based on a historiographical bias and that the clear-cut boundary between German vitalism and Naturphilosophie is historically unattested. On the contrary, they both belong to the process of conceptual genealogy that contributed to the project of a general biology. The latter emerged as the science concerned with the laws that regulate the organization of living nature as a whole. The focus on organization was, at least partially, the result of the debate surrounding the notion of "vital force", which originated in the mid-eighteenth century and caused a shift from a regulative to a constitutive understanding of teleology.
Wang, Mingzhi; Jing, Jiliang
2016-01-01
We present firstly the equation of motion for the scalar particle coupling to Einstein tensor in the Schwarzschild-Melvin black hole spacetime through the short-wave approximation. Through analysing Poincar\\'{e} sections, the power spectrum, the fast Lyapunov exponent indicator, the bifurcation diagram and the basins of attraction of the dynamical system, we confirm that the chaos exists in the geodesic motion of the coupled scalar particles. Moreover, we probe the effects of the magnetic field parameter and coupling parameter on the chaotic behavior of the particles. Our results show that the coupling together with the magnetic field brings richer physics for the motion of particles.
Readers and academic reading of Karl Marx (São Paulo, 1958-1964
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Lidiane Soares Rodrigues
2016-05-01
Full Text Available Ideas, books and concepts of Karl Marx and various Marxist authors was incorporated into scientific and cultural institutions. It is one of the political sphere importation into the academic implying sense of speed in relation to its origins and gave to Marxism, through the practices of the agents of this transfer, support for their preservation, dissemination and transformation. Concurrently, there is the incorporation of these lines to the required reading of the humanities and the repertoire of cultivated layers. Examination of appropriations that academic and cultured elites made of Marx, situate them (such work and such elites, institutionally. This is what this article does. Arguing that the legitimacy of the uses of a tradition result not only of their intrinsic value, but the work oriented agents interested in it, is elected an exemplary experience for research. This article looks at two university groups initially focused on the study of Karl Marx's work, made in the late 1950. It begins by proposing a collective biography, the reading program and the various uses they made of them. To refine the analysis and proof the advocated method selects for vertical take, within a group (the first one and a discipline (sociology, two contrasting trajectories (Fernando Henrique Cardoso and Octavio Ianni and various forms Marxism (theoretical and empirical / dominant and dominated. Finally, it discusses the profits propitiated to have operated with three concepts of cultural sociology: habitus, « field » and « patterns of intention » – taken from the works of Pierre Bourdieu and Michael Baxandall.
Kinematics of the jet in M 87 on scales of 100-1000 Schwarzschild radii
Mertens, F.; Lobanov, A. P.; Walker, R. C.; Hardee, P. E.
2016-10-01
Context. Very long baseline interferometry (VLBI) imaging of radio emission from extragalactic jets provides a unique probe of physical mechanisms governing the launching, acceleration, and collimation of relativistic outflows. Aims: VLBI imaging of the jet in the nearby active galaxy M 87 enables morphological and kinematic studies to be done on linear scales down to 100 Schwarzschild radii (Rs). Methods: The two-dimensional structure and kinematics of the jet in M 87 (NGC 4486) have been studied by applying the wavelet-based image segmentation and evaluation (WISE) method to 11 images obtained from multi-epoch Very Long Baseline Array (VLBA) observations made in January-August 2007 at 43 GHz (λ = 7 mm). Results: The WISE analysis recovers a detailed two-dimensional velocity field in the jet in M 87 at sub-parsec scales. The observed evolution of the flow velocity with distance from the jet base can be explained in the framework of MHD jet acceleration and Poynting flux conversion. A linear acceleration regime is observed up to zobs 2 mas. The acceleration is reduced at larger scales, which is consistent with saturation of Poynting flux conversion. Stacked cross correlation analysis of the images reveals a pronounced stratification of the flow. The flow consists of a slow, mildly relativistic layer (moving at β 0.5c), associated either with instability pattern speed or an outer wind, and a fast, accelerating stream line (with β 0.92, corresponding to a bulk Lorentz factor γ 2.5). A systematic difference of the apparent speeds in the northern and southern limbs of the jet is detected, providing evidence for jet rotation. The angular velocity of the magnetic field line associated with this rotation suggests that the jet in M 87 is launched in the inner part of the disk, at a distance r0 5Rs from the central engine. Conclusions: The combined results of the analysis imply that MHD acceleration and conversion of Poynting flux to kinetic energy play the dominant
Akcay, Sarp
2010-01-01
Fast, reliable orbital evolutions of compact objects around massive black holes will be needed as input for gravitational wave search algorithms in the data stream generated by the planned Laser Interferometer Space Antenna (LISA). Currently, the state of the art is a time-domain code by [Phys. Rev. D{\\bf 81}, 084021, (2010)] that computes the gravitational self-force on a point-particle in an eccentric orbit around a Schwarzschild black hole. Currently, time-domain codes take up to a few days to compute just one point in parameter space. In a series of articles, we advocate the use of a frequency-domain approach to the problem of gravitational self-force (GSF) with the ultimate goal of orbital evolution in mind. Here, we compute the GSF for a particle in a circular orbit in Schwarzschild spacetime. We solve the linearized Einstein equations for the metric perturbation in Lorenz gauge. Our frequency-domain code reproduces the time-domain results for the GSF up to $\\sim 1000$ times faster for small orbital rad...
Chen, Xiang
2012-11-01
We investigate the net force on a rigid Casimir cavity generated by vacuum fluctuations of electromagnetic field in three cases: de Sitter space-time, de Sitter space-time with weak gravitational field and Schwarzschild-de Sitter space-time. In de Sitter space-time the resulting net force follows the square inverse law but unfortunately it is too weak to be measurable due to the large universe radius. By introducing a weak gravitational field into the de Sitter space-time, we find that the net force can now be split into two parts, one is the gravitational force due to the induced effective mass between the two plates and the other one is generated by the metric structure of de Sitter space-time. In order to investigate the vacuum fluctuation force on the rigid cavity under strong gravitational field, we perform a similar analysis in Schwarzschild-de Sitter space-time and results are obtained in three different limits. The most interesting one is when the cavity gets closer to the horizon of a blackhole, square inverse law is recovered and the repulsive force due to negative energy/mass of the cavity now has an observable strength. More importantly the force changes from being repulsive to attractive when the cavity crosses the event horizon, so that the energy/mass of the cavity switches the sign, which suggests the unusual time direction inside the event horizon.
Chen, Xiang
2012-01-01
We investigate the net force on a rigid Casimir cavity generated by vacuum fluctuations of electromagnetic field in three cases, de Sitter spacetime, de Sitter spacetime with weak gravitational field and Schwarzschild-de Sitter spacetime. In de Sitter spacetime the resulting net force follows the square inverse law but unfortunately it is too weak to be measurable due to the large universe radius. By introducing a weak gravitational field into the de Sitter spacetime, we find the net force now can be splited into two parts, one is the gravitational force due to the induced effective mass between the two plates, the other one is generated by the metric structure of de Sitter spacetime. In order to investigate the vacuum fluctuation force on the rigid cavity under strong gravitational field, we perform the similar analysis in Schwarzschild-de Sitter spacetime, results are obtained in three different limits. The most interesting one is when the cavity gets closer to the horizon of a blackhole, square inverse law...
Frauendiener, Jörg; Hennig, Jörg
2017-02-01
It has recently been demonstrated (Frauendiener and Hennig 2014 Class. Quantum Grav. 31 085010) that the conformally invariant wave equation on a Minkowski background can be solved with a fully pseudospectral numerical method. In particular, it is possible to include spacelike infinity into the numerical domain, which is appropriately represented as a cylinder, and highly accurate numerical solutions can be obtained with a moderate number of gridpoints. In this paper, we generalise these considerations to the spherically-symmetric wave equation on a Schwarzschild background. In the Minkowski case, a logarithmic singularity at the future boundary is present at leading order, which can easily be removed to obtain completely regular solutions. An important new feature of the Schwarzschild background is that the corresponding solutions develop logarithmic singularities at infinitely many orders. This behaviour seems to be characteristic for massive space-times. In this sense this work is indicative of properties of the solutions of the Einstein equations near spatial infinity. The use of fully pseudospectral methods allows us to still obtain very accurate numerical solutions, and the convergence properties of the spectral approximations reveal details about the singular nature of the solutions on spacelike and null infinity. These results seem to be impossible to achieve with other current numerical methods. Moreover, we describe how to impose conditions on the asymptotic behaviour of initial data so that the leading-order logarithmic terms are avoided, which further improves the numerical accuracy.
Pappas, T; Pappas, N
2016-01-01
In this work, we study the propagation of scalar fields in the gravitational background of a higher-dimensional Schwarzschild-de-Sitter black hole as well as on the projected-on-the-brane 4-dimensional background. The scalar fields have also a non-minimal coupling to the corresponding, bulk or brane, scalar curvature. We perform a comprehensive study by deriving exact numerical results for the greybody factors, and study their profile in terms of particle and spacetime properties. We then proceed to derive the Hawking radiation spectra for a higher-dimensional Schwarzschild-de-Sitter black hole, and we study both bulk and brane channels. We demonstrate that the non-minimal field coupling, that creates an effective mass term for the fields, suppresses the energy emission rates while the cosmological constant assumes a dual role. By computing the relative energy rates and the total emissivity ratio for bulk and brane emission, we demonstrate that the combined effect of a large number of extra dimensions and val...
Rousselle, J; Cameron, R; Connaughton, V; Errando, M; Guarino, V; Humensky, T B; Jenke, P; Kieda, D; Mukherjee, R; Nieto, D; Okumura, A; Petrashyk, A; Vassiliev, V
2015-01-01
We present the design and the status of procurement of the optical system of the prototype Schwarzschild-Couder telescope (pSCT), for which construction is scheduled to begin in fall at the Fred Lawrence Whipple Observatory in southern Arizona, USA. The Schwarzschild-Couder telescope is a candidate for the medium-sized telescopes of the Cherenkov Telescope Array, which utilizes imaging atmospheric Cherenkov techniques to observe gamma rays in the energy range of 60Gev-60TeV. The pSCT novel aplanatic optical system is made of two segmented aspheric mirrors. The primary mirror has 48 mirror panels with an aperture of 9.6 m, while the secondary, made of 24 panels, has an diameter of 5.4 m. The resulting point spread function (PSF) is required to be better than 4 arcmin within a field of view of 6.4 degrees (80% of the field of view), which corresponds to a physical size of 6.4 mm on the focal plane. This goal represents a challenge for the inexpensive fabrication of aspheric mirror panels and for the precise ali...
Guarino, V.; Vassiliev, V.; Buckley, J.; Byrum, K.; Falcone, A.; Fegan, S.; Finley, J.; Hanna, D.; Kaaret, P.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Romani, R.; Wagner, R.; Woods, M.
2009-05-01
The concept of a future ground-based gamma-ray observatory, AGIS, in the energy range 20 GeV to 200 TeV is based on an array of 50-100 imaging atmospheric Cherenkov telescopes (IACTs). The anticipated improvement of AGIS sensitivity, angular resolution, and reliability of operation imposes demanding technological and cost requirements on the design of IACTs. In this submission, we focus on the optical and mechanical systems for a novel Schwarzschild-Couder two-mirror aplanatic optical system originally proposed by Schwarzschild. Emerging new mirror production technologies based on replication processes, such as cold and hot glass slumping, cured CFRP, and electroforming, provide new opportunities for cost effective solutions for the design of the optical system. We explore capabilities of these mirror fabrication methods for the AGIS project and alignment methods for optical systems. We also study a mechanical structure which will provide support points for mirrors and camera design driven by the requirement of minimizing the deflections of the mirror support structures.
Debnath, Ujjal
2015-01-01
We have studied accretion of the dark matter and dark energy onto of $(n+2)$-dimensional Schwarzschild black hole and Morris-Thorne wormhole. The mass and the rate of change of mass for $(n+2)$-dimensional Schwarzschild black hole and Morris-Thorne wormhole have been found. We have assumed some candidates of dark energy like holographic dark energy, new agegraphic dark energy, quintessence, tachyon, DBI-essence, etc. The black hole mass and the wormhole mass have been calculated in term of redshift when dark matter and above types of dark energies accrete onto them separately. We have shown that the black hole mass increases and wormhole mass decreases for holographic dark energy, new agegraphic dark energy, quintessence, tachyon accretion and the slope of increasing/decreasing of mass sensitively depends on the dimension. But for DBI-essence accretion, the black hole mass first increases and then decreases and the wormhole mass first decreases and then increases and the slope of increasing/decreasing of mass...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1998 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1999 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2002 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2001 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1994 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1997 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2003 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1995 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This collection of monthly activity reports summarizes activities on Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR during the 1975 calendar year. Resource...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2000 calendar year. The report begins...
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1996 calendar year. The report begins...
Kapischke, Matthias; Pries, Alexandra
2014-02-01
Alloplastic materials are broadly used in modern surgery. Until the middle of the 20th century, metal materials and especially silver were used because of their antimicrobial properties. With the development of a new catalytic process for the production of high-density polyethylene and polypropylene materials, a new era of prosthesis was introduced. These polymers are integral part of our everyday operations surgery, especially in hernia repair. The famous surgeon Billroth mentioned to his pupil Czerny in 1878: "If we could artificially produce tissues of the density and toughness of fascia and tendon, the secret of the radical cure of hernia would be discovered". The polypropylene developed by Karl Ziegler gave the surgeon a material for daily practice, which in its properties (nearly) achieved Billroth's initial vision. In 1963 the Nobel Prize for Chemistry was awarded to Karl Ziegler and Giulio Natta in Stockholm. Furthermore, August 11, 2013 will be the 40th anniversary of Karl Ziegler's death. This manuscript honors both days.
A tectonic window into the crystalline basement of Prins Karls Forland, Svalbard
Faehnrich, Karol; Manecki, Maciej; Schneider, David; Czerny, Jerzy; Myhre, Per Inge; Majka, Jarosław; Kośmińska, Karolina; Barnes, Chris; Maraszewska, Maria
2016-04-01
Prins Karls Forland, Svalbard, comprises a fold-thrust belt as a result of the Eocene Eurekan orogeny. The northern part of the island (north of Selvågen) is dominated by Neoproterozoic siliciclastic metasediments regionally metamorphosed to greenschist facies conditions, probably in association with one distinct stage of Caledonian tectonism. Contrasting with these low grade sequences are rocks of the Pinkie Unit, which are locally exposed along east coast of Prins Karls Forland. Amphibolite facies metasediments show evidence for at least two distinct deformation stages (including mylonitization). All the borders of the Pinkie unit are tectonic: to the east, it is a sharp boundary with the truncation of the Pinkie foliation into a N-S fault, parallel to the coast, probably associated with the formation of the Neogene Forlandsundet Graben. A ~1 km wide ductile to brittle shear zone (the Bouréefjellet shear zone) separates the low and high grade sequences along the western margin, with the Grampian Formation (low metamorphic grade quartzites, conglomerates, siltstones and slates) as the upper structural unit. Moreover, the shear zone contains outcrops of metagabbro associated with magnetite ore (Maraszewska et al. 2016, EGU). The apparent tectonostratigraphy of the Pinkie unit consists of laminated fine-grained calc-silicate rocks, locally with scapolite, and a strong E-W lineation at lower structural levels. In these rocks primary layering is apparent (S0) and parallel to metamorphic foliation plane (S1). Interconnected elongated mica crystals within S1 are deformed by C'-type shear zones. They are overlain by garnet-bearing quartzite-mylonites and garnet-bearing mylonitic mica schists with N-S to NW-SE lineations at upper structural levels. Kośmińska et al. (2015a, Mineralogia - Special Papers, vol. 44, 61-62) determined P-T metamorphic conditions of garnet-mica schist of 7-9 kbar and 550-650°C. The dominant population of metamorphic monazite present in
Eurekan deformation on Prins Karls Forland, Svalbard - new insights from Ar40/Ar39 muscovite dating
Faehnrich, Karol; Schneider, David; Manecki, Maciej; Czerny, Jerzy; Myhre, Per Inge; Majka, Jarosław; Kośmińska, Karolina; Barnes, Christopher; Maraszewska, Maria
2017-04-01
Eurekan deformation has been proven to be a complex sequence of tectonic episodes, dominated by compression in the Circum Arctic region. It was associated with early Cenozoic collision of Eurasia, North America and Greenland plates producing fold-thrust belt style of deformation. Timing of this enigmatic event has not yet been extensively resolved by radiometric dating (Piepjohn et al. 2016, Journal of the Geological Society, 173(6), 1007-1024). Reinhardt et al. (2013, Z. Dt. Ges. Geowiss., 164 (1), 131-147) dated syn-tectonic volcanic ashes at c. 60 Ma and 54 Ma on Ellesmere Island, Canada. Tagner et al. (2011, Earth and Planetary Science Letters, 303(3), 203-214) interpreted c. 49-47 Ma 40Ar/39Ar ages on trachyte flows in northern Greenland as peak compression during the Eurekan event. On Svalbard, Tessensohn et al. (2001, Geologisches Jahrbuch, B 91, 83-104) reported K/Ar whole rock ages ranging from c. 67 to 49 Ma for the slates from Svartfjella-Eidembukta-Daudmannsodden Lineament. Bentonite layers in the Central Tertiary Basin are as young as c. 56 Ma (Charles et al. 2011, Geochem. Geophys. Geosyst., 12, 1-19), predating latest deformation. Moreover, Barnes et al (2017, in prep.) applied (U-Th)/He thermochronology along the western margin of Svalbard and resolved Early to Middle Eocene heating, likely documenting burial related to thrusting. Here we present new results from 40Ar/39Ar muscovite dating of ductile to brittle shear zone on Prins Karls Forland, Svalbard, indicating Eurekan age of thrusting. Prins Karls Forland is dominated by Neoproterozoic siliciclastic metasediments (comprising Caledonian basement) regionally metamorphosed to greenschist facies conditions. A ˜1 km wide ductile to brittle shear zone (the Bouréefjellet shear zone) separates the amphibolite facies Pinkie Unit from the lower grade upper structural unit, the Grampianfjella Formation (Faehnrich et al. 2016, EGU 2016). The age of the amphibolite facies metamorphism (c. 370-355 Ma
French, R. A.; Cohen, B. A.; Miller, J. S.
2014-01-01
The Potassium-Argon Laser Experiment( KArLE), is composed of two main instruments: a spectrometer as part of the Laser-Induced Breakdown Spectroscopy (LIBS) method and a Mass Spectrometer (MS). The LIBS laser ablates a sample and creates a plasma cloud, generating a pit in the sample. The LIBS plasma is measured for K abundance in weight percent and the released gas is measured using the MS, which calculates Ar abundance in mols. To relate the K and Ar measurements, total mass of the ablated sample is needed but can be difficult to directly measure. Instead, density and volume are used to calculate mass, where density is calculated based on the elemental composition of the rock (from the emission spectrum) and volume is determined by pit morphology. This study aims to reduce the uncertainty for KArLE by analyzing pit volume relationships in several analog materials and comparing methods of pit volume measurements and their associated uncertainties.
Talarczyk, Małgorzata
2012-01-01
The point of the article is to analyse and reflect on certain symptoms of anorexia nervosa in light of Karl Jaspers and Erich Fromm's ideas and social constructivism. Contemplating the disorder in view of the philosophical ideas mentioned earlier, the author analyses such aspects of patients as: functioning on the verge of life and death, the paradoxical struggle to escape from freedom in search of independence, as well as various understandings and descriptions of anorexia in consideration of social constructivism. The author shares thoughts and poses hypotheses, trying to view anorexia in light of selected philosophical and psychological ideas, which in their general assumptions were not concerned with defining nor analysing anorexia nervosa. In view of Karl Jaspers' ideas, the author focuses on the so called 'limit-situations', in the ideas of Erich Fromm she takes notice in "Escape from Freedom" to new relations. Finally in the light of social constructivism the author focuses on the cultural context.
Sigmund Freud (1856-1939) and Karl Köller (1857-1944) and the discovery of local anesthesia.
dos Reis, Almiro
2009-01-01
The understanding, occasionally recognized, that Sigmund Freud had the intuition to use cocaine as local anesthetic for surgical procedures, or even that he played any role in the discovery of local anesthesia is not true. The objective of Freud's studies were different, and based in irrefutable evidence, Karl Köller was the real inventor of local anesthesia. In face of those facts, proper knowledge of this historically important subject is due. This report refers to the long-known properties of cocaine. It also remembers personal data, and the professional and scientific activities of Sigmund Freud and Karl Köller. It presents Freud's researches on the pathophysiological effects of cocaine. It exposes the reasons for the harsh criticism of Freud's concepts. It describes the sudden, but conscious and justified, idea of Karl Köller to study scientifically the use of cocaine as a local anesthetic in animals and humans. It indicates how those pioneering studies, that culminated with the discovery of local anesthesia by Köller and two presentations in Vienna on the subject, were done. It also reports the first ophthalmologic surgery under local anesthesia. It shows the immediate dissemination throughout the world of the discovery that marked the beginning of regional blocks. It comments several documents corroborating the role of Köller in this discovery. And, finally, it mentions the numerous homages received by Köller in different areas of the world. COCLUSIONS: Regional block was introduced by Karl Köller in 1884, when he demonstrated the feasibility of performing painless ophthalmologic surgeries by using cocaine as a local anesthetic. Sigmund Freud studied cocaine extensively, but he did not have direct participation in this important discovery.
Karl Gustaf Torsten Sjögren and the Sjögren-Larsson syndrome
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Khalid Al Aboud
2011-09-01
Full Text Available Karl Gustaf Torsten Sjögren (1896-1974 a Swedish psychiatrist and geneticist, was a pioneer of modern Swedish psychiatry. Sjögren studied medicine at the University of Uppsala. From 1932 to 1935, he was Head Physician and Director of Lillehagen Hospital in Gothenburg, and between 1935- 1945, he was physician-in-chief at the psychiatric department of Sahlgrenska Hospital in Gothenburg. Sjögren was professor of psychiatry at Karolinska Institutet from 1945 to 1961 and was elected to the Royal Swedish Academy of Sciences in 1951. Sjögren was an expert of psychiatry for the World Health Organization. Among his many contributions to medicine, he is credited for describing several medical conditions, which were later named after him, including Graefe- Sjögren syndrome, Marinesco-Sjögren syndrome, and Sjögren-Larsson syndrome (SLS. During his work on juvenile amaurotic idiocy, Sjögren forged a collaboration with Tage K.L. Larsson, a statistics lecturer at the University of Lund. Their study on the combination of oligophrenia, congenital ichthyosis, and spastic disorders in 1957 established the clinical and genetic profile of a new disease entity, later known as Sjogren-Larsson syndrome (SLS.
Karl Polanyi e a Nova Sociologia Económica: Notas sobre o conceito de (disembeddedness
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Nuno Miguel Cardoso Machado
2012-10-01
Full Text Available No contexto da Nova Sociologia Económica, Karl Polanyi é quase consensualmente considerado o “pai” do conceito de incrustação (embeddedness. Todavia, este conceito foi alvo de uma apropriação selectiva por parte da disciplina, sendo negligenciada a sua relação com o restante edifício teórico construído por Polanyi. Pode, com efeito, falar‑se de uma “grande transformação” sofrida pelo conceito de incrustação: se em Polanyi ele está associado a um nível macro(económico e é utilizado para evidenciar o carácter excepcional da economia capitalista de mercado – que se encontra desincrustada da sociedade –, na NSE, por seu turno, é normalmente associado a um nível meso (e até micro, sendo preconizado que todas as economias – incluindo a capitalista – estão incrustadas.
[Karl Jaspers. 100 years of “Allgemeine Psychopathologie” (General Psychopathology)].
Häfner, H
2013-11-01
With his "Allgemeine Psychopathologie" (general psychopathology) published in 1913, Karl Jaspers laid a comprehensive methodological and systematic foundation in psychiatry. Following Edmund Husserl, the founder of philosophical phenomenology, Jaspers introduced "static understanding" into psychopathology, i.e. the unprejudiced reproduction of conscious phenomena. From the philosopher Wilhelm Dilthey he further adopted the distinction between causal understanding as a means of accessing nature and pathological processes and hermeneutic understanding, also called genetic understanding, as a way of accessing mental phenomena. The intrusion of an event that is incomprehensible in terms of an understandable development is seen as indicating an extraconscious phenomenon or transition to a somatic process. Jaspers opted for philosophy early in his life. After quitting law studies he graduated in medicine, arrived in psychopathology without any psychiatric training, to psychology without ever studying psychology and to a chair in philosophy without a degree in philosophy. Despite believing himself to be chronically ill and to die early, Jaspers produced a life’s work almost immeasurable in scope. He died in 1969 aged 86 years.
COLDz: Karl G. Jansky Very Large Array discovery of a gas-rich galaxy in COSMOS
Lentati, L; Carilli, C L; Riechers, D; Capak, P; Walter, F; Aravena, M; da Cunha, E; Hodge, J A; Ivison, R J; Smail, I; Sharon, C; Daddi, E; Decarli, R; Dickinson, M; Sargent, M; Scoville, N; Smolcic, V
2014-01-01
The broad spectral bandwidth at mm and cm-wavelengths provided by the recent upgrades to the Karl G. Jansky Very Large Array (VLA) has made it possible to conduct unbiased searches for molecular CO line emission at redshifts, z > 1.31. We present the discovery of a gas-rich, star-forming galaxy at z = 2.48, through the detection of CO(1-0) line emission in the COLDz survey, through a sensitive, Ka-band (31 to 39 GHz) VLA survey of a 6.5 square arcminute region of the COSMOS field. We argue that the broad line (FWHM ~570 +/- 80 km/s) is most likely to be CO(1-0) at z=2.48, as the integrated emission is spatially coincident with an infrared-detected galaxy with a photometric redshift estimate of z = 3.2 +/- 0.4. The CO(1-0) line luminosity is L'_CO = (2.2 +/- 0.3) x 10^{10} K km/s pc^2, suggesting a cold molecular gas mass of M_gas ~ (2 - 8)x10^{10}M_solar depending on the assumed value of the molecular gas mass to CO luminosity ratio alpha_CO. The estimated infrared luminosity from the (rest-frame) far-infrare...
Ivan Karamazov’s rebellion in Albert Camus’ and Karl Jaspers’ interpretations
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Urszula Lisowska
2010-12-01
Full Text Available The aim of this study is to present Albert Camus’ and Karl Jaspers’ interpretations of Ivan Karamazov’s rebellion as the diagnoses of the weakness of the human intellect in confrontation with the world and the criticism of rationalism. Therefore, in the introduction I will present those fragments of the novel that characterize Ivan’s rebellion as highly abstract and theoretical. At the same time, this common literary context serves as the ground for reconstruction and comparison of the basic philosophical assumptions of each author. The intention of the remaining part of the paper is, firstly, to reconstruct A. Camus’ and K. Jaspers’ epistemology and, secondly, to analyse the arguments against Ivan’s attitude formulated by the writers. Their criticisms of the protagonist’s excessive trust in intellect is based on their own concepts of human epistemic capacity, which are related to the problems of the absurd in A. Camus’ and transcendence in K. Jaspers’ writings. The question of nihilism demands analysis of A. Camus’ idea of the nature of rebellion as both affirmative and negative, and of K. Jaspers’ notion of faith as pre-intellectual trust. Finally, their criticisms of the slogan “If there is no God, then anything is allowed” introduces the problem of freedom, which allows the comparison of the concepts of solidarity (A. Camus and communication (K. Jaspers. In the conclusion these two philosophical attitudes are discussed together. Keywords: ; ; ; ; ; ; ; ;
Karl Ove Knausgård’s My Struggle and the Serial Self
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Inge van de Ven
2016-06-01
Full Text Available This article analyzes Karl Ove Knausgård’s six-volume autobiography My Struggle in the frame of an emerging cross-medial aesthetics of the ‘serial self’. This aesthetics is informed by the technological potentialities of digital media, and by social media practices like taking a selfie or posting a blog every single day and accumulating these self-representations, without selection. The serial self is marked by continuity, real-time effects, open-endedness, rhythm, repetition, and a thematic attention to the mundane. It can be discerned in the daily comic strip, the daily selfie, and time-lapse cinema. The article embeds My Struggle in this larger, intermedial framework. Moreover, it refers to the work of psychologist Galen Strawson to argue that the self-representations in Knausgård’s work should be understood as episodic rather than diachronic in nature. This results in a sequential and paratactic, rather than causal and hierarchical, presentation of memorial material. It is claimed that serial self-representations of this type are increasingly central to our current media ecology. They offer a valuable medium for investigating, materializing, and mapping on the page the traces left by the passage of time, as serialization lends itself to performative and cumulative representations of a ‘self’ in flux, that dramatize and perform the struggles of the episodic personality in search for continuity.
Karl R. Popper’ın Tarihsicilik Eleştirisi
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Rıza Bakış
2016-06-01
Full Text Available Karl R. Popper XX. yüzyılın önemli bir bilim felsefecisidir ve bu alandaki temel savı yanlışlamacılık kuramı olarak bilinmektedir. Fakat düşüncesinin bütün uzanımlarında kendini ele veren ve onun sistemini oluşturan ise esasında eleştirel akılcılık kuramıdır. Tarihsicilik eleştirisi de bunlarla sistematik bağlamda ilintili olarak toplum ve siyaset felsefesi konusundaki görüşlerini ihtiva etmektedir. Birey olarak insanı merkeze alan Popper’ın, tarihsicilik konusundaki düşüncelerini Platon, Aristoteles, Marx ve Hegel gibi büyük sistem kurucu düşünürler üzerinden somutlaştırdığı, bütüncü yapılara karşı birtakım eleştiriler getirdiği görülmektedir. Biz bu makalemizde Popper’ın tarihsicilik eleştirisini özellikle Platon, Aristoteles, Hegel ve Karx’la ilintili eleştirilerini ele alıp tartıştık.
Rheumatoid arthritis is caused by Proteus: the molecular mimicry theory and Karl Popper.
Ebringer, Alan; Rashid, Tasha
2009-06-01
Rheumatoid arthritis is a crippling and disabling joint disease affecting over 20 million people. It occurs predominantly in women and smokers, and affects the HLA-DR1/4 individuals who carry the "shared epitope" of amino acids EQRRAA. The cause of this disease was investigated by the methods of the philosopher of science Karl Popper who suggested that scientific research should be based on bold conjectures and critical refutations. The "Popper sequences" generate new facts which then change or alter the original problem. The new facts must then be explained by any new theory. Using the "molecular mimicry" model, it was found that Proteus bacteria possess an amino acid sequence ESRRAL in haemolysin which resembles the, shared epitope, and another sequence in urease which resembles type XI collagen. Antibodies to Proteus bacteria have been found in 14 different countries. It would appear that rheumatoid arthritis is caused by an upper urinary tract infection by Proteus bacteria. Anti-Proteus therapy should be assessed in the management of this disease separately or in conjunction with existing modalities of therapy.
Sir Karl Popper (1902-1994): in memoriam, 15 years later.
Notturno, Mark Amadeus
2009-12-01
September 17th, 2009 marks the 15th anniversary of Sir Karl Popper's death. Popper was an outspoken champion of critical rationalism, and a constant critic of authoritarian tendencies in science and society. He was also one of the spiritual founders of this journal and served on its first editorial advisory board. Popper was recognized around the world as one of the 20th century's greatest philosophers of science and one of its most articulate and influential critics of Marxism and closed society. When he died, the contemporary wisdom among professional philosophers was that his philosophy was generally right-but somehow obsolete. Some commentators said that it was now obvious that scientific theories cannot be shown to be true. Others said that we had witnessed the end of history and that his critique of closed societies, while no doubt important in its day, had been fully assimilated into Western thinking and still had meaning, if at all, only for the democracies in transition that were trying to emerge from the former Soviet Union. But 15 years after his death, a look at science and society around the world gives us good reason to remember his philosophy.
[Note on the epistemology of clinical pharmacology: comparison with the approach of Karl Popper].
Boissel, J P
1999-01-01
Is clinical pharmacology a science or only an application of science? Karl Popper suggested a method to identify science and to sort it out from other logical activities such as metaphysics, whereby the falsification criterion he proposed can apply to the theory in such a way that the theory could be refuted. The clinical pharmacologist's approach requires the build-up of a therapeutic model on the basis of two other models: the physiopathologic and the pharmacological. The three-model construct is a theory. Is it scientific in the Popperian sense? From the therapeutic model, one can predict the efficacy of a drug, and the corresponding statement is tested by a clinical trial. Whatever the original statement, it is modified into a refutable one because of the use of the statistical approach in clinical trials. Furthermore, the predicate represents a hypothesis of the model validity, which will then be confronted with 'reality' through clinical experiment. As the therapeutic model is refutable, clinical pharmacology is a science in the Popperian sense.
Karl Popper versus Theodor Adorno: lições de um confronto histórico
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Angela Ganem
2012-03-01
Full Text Available Karl Popper versus Theodor Adorno: Lessons from a historical confrontation. In 1961, during the Congress of the German Society of Sociology, two great theoretical references of the XX century faced in a historical debate about the logic of the social sciences. In addition to methodological issues strict sense, the confrontation became known as a debate between positivism and dialectic. The article first deals with the theoretical trajectories of Popper and Adorno and the relation of their theories with their political and ideological certainties. On one hand, the trajectory of the Popperian epistemology is examined, its contributions and vigorous attacks on Marx in what he called 'poverty of historicism" and false predictive Marxist world, and, on the other hand, the role of Adorno in the Frankfurt School, his criticism of totalitarianism and the defense of a critical emancipatory reason. The article also deals with the confrontation itself, the exposure of Popper's twenty-seven theses that culminate with the situation logic and the method of the economy as exemplary for the social sciences and Adorno's critical perspective of sociology and society as non-separable objects. In conclusion we show how the articulation of theory with the weltanschauung of each author helps to clarify the terms of the debate and how the confrontation contributed unequivocally to the dynamics of scientific progress and for the critical history of the ideas.
A Historical Survey of Sir Karl Popper's Contribution to Quantum Mechanics
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William M. Shields
2012-11-01
Full Text Available Sir Karl Popper (1902-1994, though not trained as a physicist and embarrassed early in his career by a physics error pointed out by Einstein and Bohr, ultimately made substantial contributions to the interpretation of quantum mechanics. As was often the case, Popper initially formulated his position by criticizing the views of others - in this case Niels Bohr and Werner Heisenberg. Underlying Popper's criticism was his belief that, first, the Copenhagen interpretation of quantum mechanics abandoned scientific realism and second, the assertion that quantum theory was complete (an assertion rejected by Einstein among others amounted to an unfalsifiable claim. Popper insisted that the most basic predictions of quantum mechanics should continue to be tested, with an eye towards falsification rather than mere adding of decimal places to confirmatory experiments. His persistent attacks on the Copenhagen interpretation were aimed not at the uncertainty principle itself and the formalism from which it was derived, but at the acceptance by physicists of an unclear epistemology and ontology that left critical questions unanswered.Quanta 2012; 1: 1–12.
Cedergren, A; Lundström, M
1997-10-01
Different procedures based on the Karl Fischer reaction were investigated with respect to their applicability for water determinations in environmental hydraulic fluids: (i) continuous coulometry using a recently described diaphragm-free cell; (ii) on-line stripping of water at elevated temperature using either continuous coulometry or direct potentiometry for detection of the liberated water. Except for one of the oils, Statoil PA, which is a poly(α-olefin) with certain polymers added, no significant difference was found among coulometry using an optimized imidazole-buffered methanolic reagent containing 75% (v/v) chloroform, the two different stripping techniques (working in the temperature interval 100-110 °C), and the commercially available Hydranal Coulomat AG-H. The high stability and sensitivity of the coulometric technique described made it possible to work with sample amounts in the low milligram-range, and this is shown to increase the reliability of the coulometric method as compared to normally used procedures.
Progress in pulsed-current Karl Fischer coulometry using diaphragm-free cells.
Nordmark, U; Cedergren, A
2000-07-01
Factors influencing the accuracy of water determinations using diaphragm-free, pulsed current Karl Fischer (KF) coulometry were investigated with the new Metrohm 756 instrument. Results obtained with commercially available reagents from Riedel-deHaen and Merck were compared with home-made ones that were especially designed to minimize the formation of iodine-consuming reduction products generated in the cathode reaction. Positive errors in the range 2-5% were found for the commercial reagents as compared to 0.2-1% for the home-made ones which were buffered at about pH 10 containing modifiers like chloroform, hexanol or ethylene glycol. Except for the composition of the KF-reagent, the cathode current density and the titration rate were found to be critical parameters for the accuracy of the determinations. For all reagents investigated, the best results were obtained for the maximum generator current 400 mA (corresponding to a current density of 1,400 mA cm(-2)) in combination with a maximum titration rate of 2,000 microg min(-1). Surprisingly, the errors found under optimum conditions for the pulse technique were always somewhat larger than the corresponding values obtained with continuous coulometry.
Philosophy and Theology in Karl Barth’s Neo-Orthodoxy
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Pylaev Maksim
2016-12-01
Full Text Available In the proposed article the author explores the concept of God’s Word in theocentric theology of K. Barth and theology of early K. Barth in times of the second edition of 'Romans’, in terms of their philosophy founding. The author compares the block of philosophical and theological topics such as the theory of temporality, dialectic concept of the beginning (Ursprung and other types in philosophical discourses used by K. Barth (platonism, neo-Kantianism, existentialism, scholasticism, phenomenological philosophy and others with theology of K. Barth. The article gives a brief reconstruction of the theology of God’s Word by K. Barth in its two complementary projections as presented in the ‘Sketch of Christian Doctrine’ and ‘Dogma of the Church’. During the presentation the reader is well acquainted with the third projection of the concept of God’s Word by K. Barth at the time of the genesis of the book ‘Fides quaerens intellectum’. The article tests the hypothesis that the second edition of the ‘Romans’, ‘Fides quaerens intellectum’ and ‘Sketch of the Christian Dogma’ with ‘Church Dogma’ explicate the form of Christian theology, which, absorbing primarily the important philosophic achievements of 19–20th centuries, yet tries to stay free of them. Using various forms of philosophical discourses Karl Barth implements his own task of building a Christian theology beyond metaphysics, history and human existence.