A brief history of time, de Stephen Hawking : uma breve historia da construção de sentidos em algumas comunidades interpretativas

OpenAIRE

Nicia Adan Bonatti

1993-01-01

Resumo: Tendo como abordagem teórica os pressupostos pos-estruturalistas sobre leitura e tradução, pretendo mostrar o processo daquilo que Rosemary Arrojo chama de "palimpsesto" no exame da teadução brasileira de A Brief History of Time: From the Big Bang to Black Holes, do físico inglês Stephen W. Hawking, como exemplo da maneira pela qual um texto é apagado em uma determinada comunidade cultural, dando lugar a outra leitura do "mesmo" texto. Com efeito, este livro, de teor especializado, r...

Stephen Hawking ja tema kuulsad kihlveod / Andi Hektor

Index Scriptorium Estoniae

Hektor, Andi, 1975-

2010-01-01

Ratastooli aheldatud füüsikaikoon Hawking armastab sõlmida kihlvedusid. Viimane kihlvedu, mis puudutab gravitatsioonilainete ja inflatsiooni olemasolu, on taas päevakorda tõusnud, sest eelmisel aastal alustas mõõtmisi Plancki satelliit

La teoría del todo (2014, una mirada hacia los efectos de la Esclerosis Lateral Amiotrófica en la vida de Stephen Hawking/ The theory of everything (2014, a closer to the effects of Amiotrophic Lateral Sclerosis in the life of Stephen Hawking

Directory of Open Access Journals (Sweden)

Sofia Aguiñaga?Malanco et al.

2017-03-01

Full Text Available Stephen Hawking, autor de las teorías más fundamentales sobre el comportamiento de los agujeros negros, entreotras consideraciones sobre el tiempo y el espacio; padece de esclerosis lateral amiotrófica, la cual le fue diagnosticadadurante su último año en Oxford, tal y como se describe en la película La teoría del todo (2014 dirigida porJames Marsh y producida por Anthony McCarten. La esclerosis lateral amiotrófica (ELA o enfermedad de Lou Gehriges una alteración neurodegenerativa progresiva que ocasiona debilitamiento gradual de la musculatura voluntaria.Se caracteriza por una pérdida progresiva de la moto?neurona de la corteza motora, tronco del encéfalo y médulaespinal.

Hawking receives top US award at White House

Science.gov (United States)

Banks, Michael

2009-09-01

The Cambridge physicist Stephen Hawking has been awarded the highest US civilian honour - the presidential medal of freedom. At a ceremony at the White House last month, Hawking, together with 15 other recipients, received the 2009 award from President Barack Obama. The medal is given to individuals who make a contribution "to the security or national interests of the US, world peace, cultural or other significant public or private endeavours".

Canadian institute honours Hawking

Science.gov (United States)

Durrani, Matin

2009-11-01

The Perimeter Institute for Theoretical Physics in Waterloo, Canada, has announced that a major new extension to its campus will be known as the Stephen Hawking Centre. The extension, which is currently being built, is due to open in 2011 and will double the size of the institute. It will also provide a home for the institute's Masters students, the first of whom joined the Perimeter Institute this autumn as part of its Perimeter Scholars international programme.

Kajian Kritis Terhadap Praanggapan Metafisis-Epistemologis Kosmologi Stephen Hawking

Directory of Open Access Journals (Sweden)

Sindung Tjahyadi

2008-10-01

Full Text Available Tulisan ini pada dasarnya merupakan kajian filosofis terhadap suatu "kosmologi ilmiah".Dengan demikian terdapat dua pendekatan yang digunakan,yakni,pertama,hampiran filsafatilmu, terkait dengan aspek-aspek metodologis dari kosmologi ilmiah;dan kedua, hampirankosmologi filsafat, terkait dengan evaluasi kritis atas kosmologi Hawking dalam dimensikosmologi filsafati, terutama berkenaan dengan posisi yang diambinya terhadap unsur hakikipembangun realitas dan peran pengkosmos di dalamnya khususnya terkait dengan konsepruang-wakru, prinsip determinisme, dan hukum kekekalan energi.

Hawking's bid to save quantum theory from black holes

Science.gov (United States)

Cho, Adrian

2018-03-01

When Albert Einstein died in 1955, he had spent lonely decades trying in vain to unify the theories of gravity and electromagnetism. Stephen Hawking, the great British physicist who died last week at age 76, also worked until the end. But he focused on perhaps the most important problem in his area of physics, one his own work had posed: How do black holes preserve information encoded in the material that falls into them? Hawking realized in 1974 that through a subtle quantum effect a black hole can radiate energy and evaporate. But then a black hole should destroy any infalling information, which cannot come back out in the random radiation. Such information loss would wreck quantum mechanics, and Hawking spent much of his later years trying to figure out how a black hole could preserve information after all, even as the degenerative nerve disease amyotrophic lateral sclerosis rendered him immobile and able to speak only through a computerized voice synthesizer. Ironically, Hawking's disability may have helped him avoid the isolation that enveloped Einstein, as Hawking had to rely on collaborators to flesh out his ideas and so remained connected to his peers.

La teoría del todo (2014, una mirada hacia los efectos de la Esclerosis Lateral Amiotrófica en la vida de Stephen Hawking

Directory of Open Access Journals (Sweden)

Sofía AGUIÑAGA MALANCO

2017-06-01

Full Text Available Stephen Hawking, autor de las teorías más fundamentales sobre el comportamiento de los agujeros negros, entreotras consideraciones sobre el tiempo y el espacio; padece de esclerosis lateral amiotrófica, la cual le fue diagnosticadadurante su último año en Oxford, tal y como se describe en la película La teoría del todo (2014 dirigida por James Marsh y producida por Anthony McCarten. La esclerosis lateral amiotrófica (ELA o enfermedad de Lou Gehrig es una alteración neurodegenerativa progresiva que ocasiona debilitamiento gradual de la musculatura voluntaria.Se caracteriza por una pérdida progresiva de la moto?neurona de la corteza motora, tronco del encéfalo y médulaespinal.

Vacuum polarization and Hawking radiation

Science.gov (United States)

Rahmati, Shohreh

Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.

Higgs v Hawking: a battle of the heavyweights that has shaken the world of theoretical physics

CERN Multimedia

Connor, S

2002-01-01

Stephen Hawking was accused yesterday of receiving instant credibility because of his celebrity status. His accuser was Professor Peter Higgs, who predicted the existence of the elementary particle, the Higgs Boson, in the 1960s (1 page).

Steven Hawking to visit Texas A&M in spring

CERN Multimedia

Xavier, D

2002-01-01

Stephen Hawking will visit Texas A&M University from Feb. 24 to March 21 2003 to participate in the inaugural meeting of the George P. and Cynthia W. Mitchell Institute for Fundamental Physics. This institute will bring several of the world's top physicists to A&M for a month-long exploration of the latest ideas on topics ranging from superstrings to M-theory and supergravity (1/2 page).

Conference | From Newton to Hawking and beyond | 28 May

CERN Multimedia

2013-01-01

From Newton to Hawking and beyond: Why disability equality is relevant to the world of particle physics, Dr Tom Shakespeare.    Tuesday, 28 May 2013 - 11.30 am - 1 pm Main Auditorium – Room 500-1-001 Conference organised by the CERN Diversity Programme English with French interpretation According to the recent world report on disability, 15% of the world’s population is disabled.  Among that group could be numbered famous physicists such as Isaac Newton and Paul Dirac, neither of whom could be classed as “neuro-typical”, and Stephen Hawking.  This presentation will provide some basic data about global disability, and the socially imposed barriers which disabled people face.  It will also include some stories about high achieving people with disabilities.  Finally, some practical suggestions will be offered on how to respect and include people with disabilities in the workplace. Tom Shakespeare is a social sci...

Hawking temperature: an elementary approach based on Newtonian mechanics and quantum theory

Science.gov (United States)

Pinochet, Jorge

2016-01-01

In 1974, the British physicist Stephen Hawking discovered that black holes have a characteristic temperature and are therefore capable of emitting radiation. Given the scientific importance of this discovery, there is a profuse literature on the subject. Nevertheless, the available literature ends up being either too simple, which does not convey the true physical significance of the issue, or too technical, which excludes an ample segment of the audience interested in science, such as physics teachers and their students. The present article seeks to remedy this shortcoming. It develops a simple and plausible argument that provides insight into the fundamental aspects of Hawking’s discovery, which leads to an approximate equation for the so-called Hawking temperature. The exposition is mainly intended for physics teachers and their students, and it only requires elementary algebra, as well as basic notions of Newtonian mechanics and quantum theory.

Stephen R. Decker | NREL

Science.gov (United States)

Stephen R. Decker Photo of Stephen R. Decker Steve Decker Group Research Manager III-Molecular -364 (2001) View all NREL patents for Stephen R. Decker. Featured Publications "Working towards Publications for Stephen R. Decker. Please contact me with research questions, ideas for collaborations, and

Development of the Hawk/Nike Hawk sounding rocket vehicles

Science.gov (United States)

Flowers, B. J.

1976-01-01

A new sounding rocket family, the Hawk and Nike-Hawk Vehicles, have been developed, flight tested and added to the NASA Sounding Rocket Vehicle Stable. The Hawk is a single-stage vehicle that will carry 35.6 cm diameter payloads weighing 45.5 kg to 91 kg to altitudes of 78 km to 56 km, respectively. The two-stage Nike-Hawk will carry payloads weighing 68 kg to 136 kg to altitudes of 118 km to 113 km, respectively. Both vehicles utilize the XM22E8 Hawk rocket motor which is available in large numbers as a surplus item from the U.S. Army. The Hawk fin and tail can hardware were designed in-house. The Nike tail can and fin hardware are surplus Nike-Ajax booster hardware. Development objectives were to provide a vehicle family with a larger diameter, larger volume payload capability than the Nike-Apache and Nike-Tomahawk vehicles at comparable cost. Both vehicles performed nominally in flight tests.

My Most Memorable AAS Meeting, or How Stephen Hawking's Chauffeur and Chubby Wise's Fiddle Are Related to the Hubble Deep Field (At Least In My Mind and Experience!)

Science.gov (United States)

Lucas, R. A.

1999-05-01

Sometimes, in the most extraordinary conditions and times, strange things happen which remind us of just how small a world we really inhabit, and how so many varied things may suddenly be juxtaposed in our lives, and in the lives of others. My most memorable AAS meeting involves not only the meeting but events while getting there. It was January 1996, and we had just finished our observations and initial data reduction of the Hubble Deep Field, the members of the HDF working group doggedly coming in to the STScI by various means over the December holidays and the New Year, in the midst of several blizzards which even closed STScI for a number of days. Not surprisingly, work on the HDF AAS presentations was ongoing until the last minute, until people left snowy Baltimore for sunny San Antonio. My street was plowed for the first time in a week a few hours before my 6AM flight, so after digging out my car, with no time for sleep, between 3AM and 6AM on the morning I left, I soon discovered my own surprising connections between Stephen Hawking's chauffeur, Chubby Wise's fiddle, and the Hubble Deep Field. I'll elaborate in this paper if you're curious!

Two autographs: Cecile Dewitt and Robert Hawking (for Steven Hawking)

Science.gov (United States)

Gaina, Alex

2007-12-01

Two autographs given to author by professor Cecile Dewitt and Robert Hawking (the son of Steven Hawking for his father) in 1987 during the Quantum Gravity Seminar in Moscow are presented. The first was given during a visit to Physical Institute of the Academy of sciences of the USSR, where a seminar held in the Theoretical department. the second was given during a lunch with Steven Hawking, Andrei Linde and Robert Hawking at the 2-nd floor of the Conference floor.

The question of the existence of God in the book of Stephen Hawking: A brief history of time

NARCIS (Netherlands)

Driessen, A.; Driessen, A; Suarez, A.

1997-01-01

The continuing interest in the book of S. Hawking "A Brief History of Time" makes a philosophical evaluation of the content highly desirable. As will be shown, the genre of this work can be identified as a speciality in philosophy, namely the proof of the existence of God. In this study an attempt

UH-60M Black Hawk Helicopter (UH-60M Black Hawk)

Science.gov (United States)

2016-12-01

Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-341 UH-60M Black Hawk Helicopter (UH-60M Black Hawk ) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 21, 2016 18:25:45 UNCLASSIFIED UH-60M Black Hawk December 2015 SAR March 21, 2016 18...Operational Requirements Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost UH-60M Black Hawk

News and Views: Very short GRBs may be Hawking radiation source; CubeSat for the UK: UKube1 seeks payloads; Galactic centre? It's just up there… There could be a lot of Earths out there

Science.gov (United States)

2010-12-01

A particular group of gamma-ray bursts, those of very short duration, have characteristics that suggest they may be the signature of an evaporating primordial black hole - the Hawking radiation proposed by Stephen Hawking in 1974. The UK Space Agency is seeking small innovative payloads for the pilot UK CubeSat, UKube1. Planet-hunters have examined the distribution of exoplanets around stars like the Sun in our galaxy, and concluded that they can expect to find planets the size of Earth around a quarter of them - 46 billion or thereabouts.

STS-114 Crew Interview: Stephen Robinson

Science.gov (United States)

2003-01-01

Stephen Robinson, Mission Specialist 2 (MS2), of the STS-114 space mission is seen during a prelaunch interview. He discusses his duties as flight engineer, Extravehicular Activity 2 (EVA 2) spacewalker, and medical officer. Robinson answers questions about his interests in spaceflight and the specific goals of the mission. He identifies this mission as the International Space Station Resupply Mission because supplies and experiments are brought to the International Space Station and Expedition 6 crew of Commander Kenneth Bowersox, and Flight Engineers Donald Pettit and Nikolai Budarin are returning to Earth. Lastly, he talks about the docking of the Space Shuttle Atlantis with the International Space Station. He looks forward to this experience in space.

Bee-hawking by the wasp, Vespa velutina, on the honeybees Apis cerana and A. mellifera.

Science.gov (United States)

Tan, K; Radloff, S E; Li, J J; Hepburn, H R; Yang, M X; Zhang, L J; Neumann, P

2007-06-01

The vespine wasps, Vespa velutina, specialise in hawking honeybee foragers returning to their nests. We studied their behaviour in China using native Apis cerana and introduced A. mellifera colonies. When the wasps are hawking, A. cerana recruits threefold more guard bees to stave off predation than A. mellifera. The former also utilises wing shimmering as a visual pattern disruption mechanism, which is not shown by A. mellifera. A. cerana foragers halve the time of normal flight needed to dart into the nest entrance, while A. mellifera actually slows down in sashaying flight manoeuvres. V. velutina preferentially hawks A. mellifera foragers when both A. mellifera and A. cerana occur in the same apiary. The pace of wasp-hawking was highest in mid-summer but the frequency of hawking wasps was three times higher at A. mellifera colonies than at the A. cerana colonies. The wasps were taking A. mellifera foragers at a frequency eightfold greater than A. cerana foragers. The final hawking success rates of the wasps were about three times higher for A. mellifera foragers than for A. cerana. The relative success of native A. cerana over European A. mellifera in thwarting predation by the wasp V. velutina is interpreted as the result of co-evolution between the Asian wasp and honeybee, respectively.

The question of the existence of God in the book of Stephen Hawking: A brief history of time

OpenAIRE

Driessen, A.; Driessen, A; Suarez, A.

1997-01-01

The continuing interest in the book of S. Hawking "A Brief History of Time" makes a philosophical evaluation of the content highly desirable. As will be shown, the genre of this work can be identified as a speciality in philosophy, namely the proof of the existence of God. In this study an attempt is given to unveil the philosophical concepts and steps that lead to the final conclusions, without discussing in detail the remarkable review of modern physical theories. In order to clarify these ...

Notes on breeding sharp-shinned hawks and Cooper’s hawks in Barnwell County, South Carolina.

Energy Technology Data Exchange (ETDEWEB)

Vukovich, Mark; Kilgo, John, C.

2009-07-01

Abstract - Breeding records of Accipiter striatus (Sharp-shinned Hawks) in the southeastern US are scattered and isolated. We documented a Sharp-shinned Hawk and Accipiter cooperii (Cooper’s Hawk) nest while conducting a telemetry study on Melanerpes erythrocephalus (Red-headed Woodpeckers) in Barnwell County, SC in 2006 and 2007. We report the first known nest of a Sharp-shinned Hawk in Barnwell County, SC and the first report of Sharp-shinned Hawks preying upon Red-headed Woodpeckers. Thirteen of 93 (13.9 %) woodpeckers were killed by accipiters in the summers of 2006 and 2007. Large, contiguous forests managed for Picoides borealis (Red-cockaded Woodpeckers) may be used by breeding Sharp-shinned Hawks. The bright plumage, loud calls, and behavior of Red-headed Woodpeckers, particularly during the nestling stage, may make them conspicuous prey for accipiters.

Universality of the Hawking effect

International Nuclear Information System (INIS)

Unruh, William G.; Schuetzhold, Ralf

2005-01-01

Addressing the question of whether the Hawking effect depends on degrees of freedom at ultrahigh (e.g., Planckian) energies/momenta, we propose three rather general conditions on these degrees of freedom under which the Hawking effect is reproduced to lowest order. As a generalization of Corley's results, we present a rather general model based on nonlinear dispersion relations satisfying these conditions together with a derivation of the Hawking effect for that model. However, we also demonstrate counter-examples, which do not appear to be unphysical or artificial, displaying strong deviations from Hawking's result. Therefore, whether real black holes emit Hawking radiation remains an open question and could give nontrivial information about Planckian physics

Steven Hawking with Robert Aymar

CERN Multimedia

Maximilien Brice

2006-01-01

Steven Hawking is seen meeting with CERN's Director-General, Robert Aymar. Hawking visited CERN between 24 September and 1 October 2006. During his stay he gave two lectures and toured the LHC, which may provide insights into Hawking's most famous area of study, black holes.

The Hawking effect

International Nuclear Information System (INIS)

Saffary, T.

2001-02-01

The subject of this diploma thesis is the Hawking effect. We study Fredenhagen and Haag's proof of the Hawking radiation in the framework of a semiclassical theory, the quantum field theory in curved spacetime. In particular we give an exact derivation for the short distance behaviour of the two-point function on the Schwarzschild radius

Notes on breeding sharp-shinned hawks and cooper’s hawks in Barnwell County, South Carolina

Science.gov (United States)

Mark Vukovich; John C. Kilgo

2009-01-01

Breeding records of Accipiter striatus (Sharp-shinned Hawks) in the southeastern US are scattered and isolated. We documented a Sharp-shinned Hawk and Accipiter cooperii (Cooper’s Hawk) nest while conducting a telemetry study on Melanerpes erythrocephalus (Red-headed Woodpeckers) in Barnwell County, SC in 2006 and 2007. We report the first known nest of a Sharp-shinned...

Is Hawking radiation physically reasonable?

International Nuclear Information System (INIS)

Ahmed, M.

1995-07-01

Hawking radiation is observed in a general spacetime which includes all the black hole spacetimes as well as various types of other spacetimes which are not interesting form the physical point of view like black hole spacetimes. Even Hawking radiation is observed in NUT spacetime which is sometimes considered as unphysical. So naturally arises the question whether Hawking radiation is physically reasonable. (author). 22 refs

76 FR 30947 - Stephen Lee Seldon: Debarment Order

Science.gov (United States)

2011-05-27

...] Stephen Lee Seldon: Debarment Order AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY... Act (the FD&C Act) permanently debarring Stephen Lee Seldon, M.D. from providing services in any... authority delegated to the Director (Staff Manual Guide 1410.35), finds that Stephen Lee Seldon has been...

Book Review: The future of spacetime. Stephen William Hawking (ed.); Kip S. Thorne, Igor Novikov, Timothy Ferris, Alan Lightman, and Richard Price, W.W. Norton & Company, 2002, 224 pp., US 25.95, ISBN 0393020223

Science.gov (United States)

Smeenk, Chris

2003-12-01

The study of Einstein's theory of general relativity experienced a renaissance beginning in the early 1960s. Prior to this resurgence of interest, general relativity was isolated from mainstream physics-admired for its elegance, perhaps, but only from a distance. The generation of students who risked their careers by entering this neglected field has now reached the age of festschrifts. In June of 2000, Caltech hosted ;Kipfest,; a conference in honor of Kip Thorne's 60th birthday. Thorne started graduate school at Princeton in 1962 and began research in general relativity under John Wheeler's guidance in the heady early days of the renaissance. Since then, he has played a prominent role in general relativity: as co-author of the influential textbook Gravitation, as a leader in research regarding astrophysical applications of Einstein's theory, and as a co-founder and chief advocate for the Laser Interferometer Gravitational Wave Observatory (LIGO), to mention a few aspects of his far-reaching work. ;Kipfest; included 14 speakers discussing fields to which Thorne has contributed. But the conference also reflected Thorne's long-standing commitment to communicating science to a general audience: Igor Novikov, Stephen Hawking, Timothy Ferris, and Alan Lightman gave popular talks at ;Kipfest,; with Thorne himself tricked into delivering a fifth. The Future of Spacetime gathers adaptations of these five lectures, along with a lengthy introductory essay by Richard Price.

Comparison of the breeding biology of sympatric red-tailed Hawks, White-tailed Hawks, and Crested Caracaras in south Texas

Science.gov (United States)

Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

2009-01-01

We compared the breeding biology of sympatric nesting Red-tailed Hawks (Buteo jamaicensis), White-tailed Hawks (Buteo albicaudatus), and Crested Caracaras (Caracara cheriway) in south Texas during 2003 and 2004. We monitored 46 breeding attempts by Red-tailed Hawks, 56 by White-tailed Hawks, and 27 by Crested Caracaras. Observed nesting success was similar for Red-tailed Hawks (62%) and Crested Caracaras (61%), but lower for White-tailed Hawks (51%). Daily survival rates (0.99) were the same for all three species. Red-tailed Hawks and White-tailed Hawks both fledged 1.13 young per nesting pair and Crested Caracaras fledged 1.39 young per nesting pair. All three species nested earlier in 2004 than in 2003; in addition, the overall nesting density of these three species almost doubled from 2003 (1.45 pairs/km2) to 2004 (2.71 pairs/km2). Estimated productivity of all three species was within the ranges reported from other studies. Given extensive and progressive habitat alteration in some areas of south Texas, and the limited distributions of White-tailed Hawks and Crested Caracaras, the presence of large ranches managed for free-range cattle production and hunting leases likely provides important habitat and may be key areas for conservation of these two species. ?? 2009 The Raptor Research Foundation, Inc.

En verden uden ende

DEFF Research Database (Denmark)

Pedersen, Jens Olaf Pepke

2017-01-01

Multivers. Er der kun ét, eller er der utallige universer med hver sine naturlove? Det er emnet for en nyoversat bog af fysikeren Stephen Hawking og forfatteren Leonard Mlodinow.......Multivers. Er der kun ét, eller er der utallige universer med hver sine naturlove? Det er emnet for en nyoversat bog af fysikeren Stephen Hawking og forfatteren Leonard Mlodinow....

Performance updates of HAWK-I and preparation for the commissioning of the system GRAAL+HAWK-I

Science.gov (United States)

Hibon, Pascale; Paufique, Jerome; Kuntschner, Harald; Dobrzycka, Danuta; Le Louarn, Miska; Valenti, Elena; Neeser, Mark; Pompei, Emanuela; Arsenault, Robin; Siebenmorgen, Ralf; Madec, Pierre-Yves; Petr-Gotzens, Monika; La Fuente, Carlos; Urrutia, Josefina; Valenzuela, Javier; Castillo, Roberto; Baksai, Pedro; Garcia Dabo, Cesar Enrique; Jost, Andreas; Argomedo, Javier; Kolb, Johann; Kiekebusch, Mario; Hubin, Norbert; Duhoux, Philippe; Conzelmann, Ralf Dieter; Donaldson, Robert; Tordo, Sebastien; Huber, Stefan

2016-08-01

The High Acuity Wide field K-band Imager (HAWK-I) instrument is a cryogenic wide field imager operating in the wavelength range 0.9 to 2.5 microns. It has been in operations since 2007 on the UT4 at the Very Large Telescope Observatory in seeing-limited mode. In 2017-2018, GRound Layer Adaptive optics Assisted by Lasers module (GRAAL) will be in operation and the system GRAAL+HAWK-I will be commissioned. It will allow: deeper exposures for nearly point-source objects, or shorter exposure times for reaching the same magnitude, and/or deeper detection limiting magnitude. With GRAAL, HAWK-I will operate more than 80% of the time with an equivalent K-band seeing of 0.55" (instead of 0.7" without GRAAL). GRAAL is already installed and the operations without adaptive optics were commissioned in 2015. We discuss here the latest updates on performance from HAWK-I without Adaptive Optics (AO) and the preparation for the commissioning of the system GRAAL+HAWK-I.

Boltzmann factor and Hawking radiation

International Nuclear Information System (INIS)

Ryskin, Gregory

2014-01-01

Hawking radiation has thermal spectrum corresponding to the temperature T H =(8πM) −1 , where M is the mass (energy) of the black hole. Corrections to the Hawking radiation spectrum were discovered by Kraus and Wilczek (1995) and Parikh and Wilczek (2000). Here I show that these corrections follow directly from the basic principles of thermodynamics and statistical mechanics. In essence, it is the Boltzmann factor that ought to be corrected; corrections to the Hawking (or any other) radiation spectrum then follow necessarily

Canonising the Hartle-Hawking proposal

International Nuclear Information System (INIS)

Louko, J.

1988-01-01

The canonical formulation of the Hartle-Hawking proposal is discussed in a class of spatially homogeneous minisuperspace models. Relying on arguments of consistency with the classical variational principle, we find a set of canonical variables in which the Hartle-Hawking boundary condition is abtained by fixing in the path integral the final values of the canonical coordinates but the initial values of the canonical momenta. A canonical measure of this kind offers a natural starting point for skeletonising the minisuperspace Hartle-Hawking path integral. (orig.)

Cooper's Hawk (Accipiter cooperii)

Science.gov (United States)

Jean-Luc E. Cartron; Patricia L. Kennedy; Rob Yaksich; Scott H. Stoleson

2010-01-01

The Cooper's Hawk (Accipiter cooperii) is intermediate in size between the Northern Goshawk (Accipiter gentilis) and the Sharp-shinned Hawk (A. striatus), northern North America's other two accipiters. The two sexes are almost alike in plumage, but as in both of the other species, the female is noticeably larger. According to Wheeler and Clark (1995), a...

Bayesian inference for Hawkes processes

DEFF Research Database (Denmark)

Rasmussen, Jakob Gulddahl

The Hawkes process is a practically and theoretically important class of point processes, but parameter-estimation for such a process can pose various problems. In this paper we explore and compare two approaches to Bayesian inference. The first approach is based on the so-called conditional...... intensity function, while the second approach is based on an underlying clustering and branching structure in the Hawkes process. For practical use, MCMC (Markov chain Monte Carlo) methods are employed. The two approaches are compared numerically using three examples of the Hawkes process....

Bayesian inference for Hawkes processes

DEFF Research Database (Denmark)

Rasmussen, Jakob Gulddahl

2013-01-01

The Hawkes process is a practically and theoretically important class of point processes, but parameter-estimation for such a process can pose various problems. In this paper we explore and compare two approaches to Bayesian inference. The first approach is based on the so-called conditional...... intensity function, while the second approach is based on an underlying clustering and branching structure in the Hawkes process. For practical use, MCMC (Markov chain Monte Carlo) methods are employed. The two approaches are compared numerically using three examples of the Hawkes process....

Particle energy and Hawking temperature

International Nuclear Information System (INIS)

Ding Chikun; Wang Mengjie; Jing Jiliang

2009-01-01

Some authors have recently found that the tunneling approach gives a different Hawking temperature for a Schwarzschild black hole in a different coordinate system. In this Letter, we find that to work out the Hawking temperature in a different coordinate system by the tunneling approach, we must use the correct definition of the energy of the radiating particles. By using a new definition of the particle energy, we obtain the correct Hawking temperature for a Schwarzschild black hole in two dynamic coordinate systems, the Kruskal-Szekers and dynamic Lemaitre coordinate systems.

77 FR 61003 - Stephen C. Delaney, Jr.: Debarment Order

Science.gov (United States)

2012-10-05

...] Stephen C. Delaney, Jr.: Debarment Order AGENCY: Food and Drug Administration, HHS. ACTION: Notice... Cosmetic Act (the FD&C Act) debarring Stephen C. Delaney, Jr. for a period of 5 years from importing....35), finds that Mr. Stephen C. Delaney, Jr. has been convicted of a felony under Federal law for...

The pair correlation function of spatial Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Torrisi, Giovanni Luca

2007-01-01

Spatial Hawkes processes can be considered as spatial versions of classical Hawkes processes. We derive the pair correlation function of stationary spatial Hawkes processes and discuss the connection to the Bartlett spectrum and other summary statistics. Particularly, results for Gaussian fertility...... rates and the extension to spatial Hawkes processes with random fertility rates are discussed....

Second order analysis for spatial Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Torrisi, Giovanni Luca

We derive summary statistics for stationary Hawkes processes which can be considered as spatial versions of classical Hawkes processes. Particularly, we derive the intensity, the pair correlation function and the Bartlett spectrum. Our results for Gaussian fertility rates and the extension...... to marked Hawkes processes are discussed....

Hawking temperature from tunnelling formalism

OpenAIRE

Mitra, P.

2007-01-01

It has recently been suggested that the attempt to understand Hawking radiation as tunnelling across black hole horizons produces a Hawking temperature double the standard value. It is explained here how one can obtain the standard value in the same tunnelling approach.

Hawking radiation in string theories

International Nuclear Information System (INIS)

Sakai, N.

1986-01-01

String theories in a uniform gravitational field are studied to examine the Hawking radiation. An upper limit is found for the strength of the possible gravitational field: the corresponding Hawking temperature cannot be larger than the Hagedorn limiting temperature divided by π

Hawking radiation from acoustic black holes, short distance and back reaction effects

International Nuclear Information System (INIS)

Balbinot, R.; Fabbri, A.; Parentani, R.

2004-01-01

Using the action principle we first review how linear density perturbations (sound waves) in an Eulerian fluid obey a relativistic equation: the d'Alembert equation. This analogy between propagation of sound and that of a massless scalar field in a Lorentzian metric also applies to non-homogeneous flows. In these cases, sound waves effectively propagate in a curved four-dimensional acoustic metric whose properties are determined by the flow. Using this analogy, we consider regular flows which become supersonic, and show that the acoustic metric behaves like that of a black hole. The analogy is so good that, when considering quantum mechanics, acoustic black holes should produce a thermal flux of Hawking phonons. We then focus on two interesting questions related to Hawking radiation which are not fully understood in the context of gravitational black holes due to the lack of a theory of quantum gravity. The first concerns the calculation of the modifications of Hawking radiation which are induced by dispersive effects at short distances, approaching the atomic scale when considering sound. We generalize existing treatments and calculate the modifications caused by the propagation near the black-hole horizon. The second question concerns back reaction effects. We return to the Eulerian action, compute second-order effects, and show that the back reaction of sound waves on the fluid's flow can be expressed in terms of their stress-energy tensor. Using this result in the context of Hawking radiation, we compute the secular effect on the background flow

Breeding ecology of ferruginous hawks, Swainson’s hawks, and northern harriers in south-central North Dakota : Proposal

Data.gov (United States)

Department of the Interior — Project proposal for research survey to document the breeding ecology of ferruginous hawks, Swainson’s hawk, and northern harrier in Kulm Wetland Management District...

Ferruginous hawks on the Yakima Training Center

Energy Technology Data Exchange (ETDEWEB)

Mazaika, R.; Cadwell, L.L.

1994-07-01

Habitat quality for ferruginous hawks (Buteo regalis) is largely determined by availability of nest sites and adequate prey base. A limitation of one of these will limit the number of hawks in an area. In general, ferruginous hawks are adaptable to various nesting substrates and will nest in proximity to other closely related sympatric species (e.g., red-tailed hawk, Swainson`s hawk). This analysis focused on an assessment of prey base availability and habitat disturbance in the vicinity of historic nest sites and small mammal trap sites on the Yakima Training Center (YTC) in Washington State. The primary ground-disturbing activities on the YTC are associated with military training, fire, and grazing. In addition to the direct effect these activities can have on ferruginous hawks, indirect effects may result from changes in composition, density, and structure of vegetation that subsequently alter faunal population numbers and species diversity. A summary of results of small mammal trapping, population estimation, vegetative analysis and disturbance rating at seven trap sites during the time period of June through August of 1993 are presented.

Ferruginous hawk

Science.gov (United States)

Hall, R.S.; Glinski, R.L.; Ellis, D.H.; Ramakka, J.M.; Base, D.L.; Glinski, Richard L.; Pendleton, Beth Giron; Moss, Mary Beth; LeFranc, Maurice N.=; Millsap, Brian A.; Hoffman, Stephen W.

1988-01-01

In the Southwest, the ferruginous hawk is a local and isolated breeder and an uncommon but consistent winter visitor. Apparently, the breeding range of this species in the Southwest was historically much greater than today. The ferruginous hawk is being considered for listing by the U.S. Fish and Wildlife Service but remains unclassified by the individual states comprising the Southwest region. Habitat and diet information is summarized. Nest location and structure, breeding, and wintering biology are also discussed. Long-term and seasonal monitoring is conducted annually at several nest locations in New Mexico, while documented reproductive efforts in Arizona, Texas and Oklahoma are extremely rare and isolated. Research and management recommendations include population and habitat surveys, dietary and reproductive investigations, and habitat protection.

Thermality of the Hawking flux

Energy Technology Data Exchange (ETDEWEB)

Visser, Matt [School of Mathematics, Statistics, and Operations Research,Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand)

2015-07-03

Is the Hawking flux “thermal”? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word “thermal”. The original 1850’s notions of thermality — based on classical thermodynamic reasoning applied to idealized “black bodies” or “lamp black surfaces” — when supplemented by specific basic quantum ideas from the early 1900’s, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but without any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only approximately Planck-shaped over an explicitly bounded range of frequencies. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is approximately Planck-shaped from both above and below — the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.

Thermality of the Hawking flux

International Nuclear Information System (INIS)

Visser, Matt

2015-01-01

Is the Hawking flux “thermal”? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word “thermal”. The original 1850’s notions of thermality — based on classical thermodynamic reasoning applied to idealized “black bodies” or “lamp black surfaces” — when supplemented by specific basic quantum ideas from the early 1900’s, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but without any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only approximately Planck-shaped over an explicitly bounded range of frequencies. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is approximately Planck-shaped from both above and below — the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.

Hawking Radiation As Tunneling

International Nuclear Information System (INIS)

Parikh, Maulik K.; Wilczek, Frank

2000-01-01

We present a short and direct derivation of Hawking radiation as a tunneling process, based on particles in a dynamical geometry. The imaginary part of the action for the classically forbidden process is related to the Boltzmann factor for emission at the Hawking temperature. Because the derivation respects conservation laws, the exact spectrum is not precisely thermal. We compare and contrast the problem of spontaneous emission of charged particles from a charged conductor

Itika, Josephat Stephen

African Journals Online (AJOL)

Itika, Josephat Stephen. Vol 13, No 1 (2004) - Articles Contextual Innovation, Growth And Income In Garment Micro Businesses: Limitations From Questionnaire-Based Data Abstract. ISSN: 0856-6372. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about ...

Zone-tailed Hawk (Buteo albonotatus)

Science.gov (United States)

Scott H. Stoleson; Giancarlo Sadoti

2010-01-01

The Zone-tailed Hawk (Buteo albonotatus) might well be dubbed "the Great Pretender" because it so closely resembles the ubiquitous Turkey Vulture (Cathartes aura) in appearance and behavior as to be frequently mistaken for it. In the border regions where it lives, it may be confused as well with another "Mexican" raptor, the Common Black-Hawk (...

Gambling with the Universe

Science.gov (United States)

Hawking, Stephen

2002-05-01

This is an excerpt from Stephen Hawking's book The Universe in a Nutshell. Roger Penrose and Stephen Hawking, Lucasian Professor of Mathematics at the University of Cambridge, were able to show that Einstein's General Theory of Relativity implied that the universe and time itself must have had a beginning in a tremendous explosion. The discovery of the expansion of the universe is one of the great intellectual revolutions of the twentieth century.

Celebrating Stephen Robertson's retirement

NARCIS (Netherlands)

Hiemstra, Djoerd; Tait, J.; MacFarlane, A; Belkin, N.

2013-01-01

Stephen Robertson retired from the Microsoft Research Lab in Cambridge during the summer of 2013 after a long career as one of the most influential, well-liked and eminent researchers in Information Retrieval throughout the world.

Special people visit the ATLAS cavern

CERN Multimedia

Muriel

ATLAS has been host to many important visitors lately. Here are a selected few: Professor Stephen Hawking visits the ATLAS cavern On Tuesday 26 September 2006 the ATLAS Collaboration was honoured by a very special visit to the detector in the underground cavern. We were pleased to guide Professor Stephen Hawking, the famous cosmologist holding the post of Lucasian Professor of Mathematics at Cambridge University (position held by Isaac Newton in the 17th century), on a tour of the ATLAS pit and the LHC tunnel. The visit was accompanied by a few colleagues from the CERN Theory group, and was only possible thanks to the professional assistance of Olga Beltramello and Bernard Lebegue, who had also taken care of all the necessary preparatory work in the cavern. Professor Hawking was very keen to check for himself the status of the detector installation, and he admired, in particular, the spectacular TGC big wheel on side C. (left) Stephen Hawking in the ATLAS cavern side-C (right) and in the LHC tunnel...

Conferencia del Profesor Stephen Hawking en la ceremonia de apertura del 25 Aniversario de los Premios Príncipe de Asturias

OpenAIRE

Hawking, Stephen

2012-01-01

Tras señalar que la Segunda Ley de la Termodinámica se cumple porque el universo empezó en un estado ordenado, y que para predecir el estado inicial se deben ocupar tanto la relatividad general como la teoría cuántica, Hawking propone que el universo no tiene una sola historia sino todas las historias posibles, cada una con su propia amplitud de probabilidad. Postula que las historias del universo dependen de lo que está siendo medido, al revés de la idea habitual de que el universo tiene una...

Deformation of contour and Hawking temperature

International Nuclear Information System (INIS)

Ding Chikun; Jing Jiliang

2010-01-01

It was found that, in an isotropic coordinate system, the tunneling approach brings a factor of 1/2 for the Hawking temperature of a Schwarzschild black hole. In this paper, we address this kind of problem by studying the relation between the Hawking temperature and the deformation of the integral contour for the scalar and Dirac particles tunneling. We find that the correct Hawking temperature can be obtained exactly as long as the integral contour deformed corresponding to the radial coordinate transform if the transformation is a non-regular or zero function at the event horizon.

The temperature in Hawking radiation as tunneling

International Nuclear Information System (INIS)

Zhang Baocheng; Cai Qingyu; Zhan Mingsheng

2009-01-01

The quasi-classical method of deriving Hawking radiation under the consideration of canonical invariance is investigated. We find that the horizon should be regarded as a two-way barrier and the ingoing amplitude should be calculated according to the negative energy particles tunneling into the black hole because of the whole space-time interchange and thus the standard Hawking temperature is recovered. We also discuss the advantage of the Painleve coordinates in Hawking radiation as tunneling

Generalized Bekenstein-Hawking system: logarithmic correction

International Nuclear Information System (INIS)

Chakraborty, Subenoy

2014-01-01

The present work is a generalization of the recent work [arXiv.1206.1420] on the modified Hawking temperature on the event horizon. Here the Hawking temperature is generalized by multiplying the modified Hawking temperature by a variable parameter α representing the ratio of the growth rate of the apparent horizon to that of event horizon. It is found that both the first and the generalized second law of thermodynamics are valid on the event horizon for any fluid distribution. Subsequently, the Bekenstein entropy is modified on the event horizon and the thermodynamical laws are examined. Finally, an interpretation of the parameters involved is presented. (orig.)

Evidence of hawking (falconry) from bird and mammal bones

NARCIS (Netherlands)

Prummel, W.

1997-01-01

This paper deals with the archaeozoological and archaeological evidence for hawking, or falconry. The methods and history of hawking in Europe are described, after which five types of evidence for hawking are discussed. These are illustrated with material from the Slavonic stronghold of Oldenburg in

Letters in this Issue

Science.gov (United States)

1998-01-01

Reforming the General Chemistry Textbook individual letters by Edward T. Samulski; Stephen J. Hawkes; Stephen J. Fisher; J. Stephen Hartman; A. R. H. Cole; Stanley Pine, Ronald Archer, and Herbert Kaesz; Jimmy Reeves; Robert Hill; and Brock Spencer, C. Bradley Moore and Nedah Rose. Re: article by R. J. Gillespie The author replies

Hawking radiation from a rotating acoustic black hole

International Nuclear Information System (INIS)

Zhang Lichun; Li Huaifan; Zhao Ren

2011-01-01

Using the new global embedding approach and analytical continuation method of wave function we discuss Hawking radiation of acoustic black holes. Unruh-Hawking temperature of the acoustic black hole is derived. The corresponding relation between these methods calculating Hawking radiation of acoustic black hole is established. The calculation result shows that the contributions of chemical potential to the ingoing wave and the outgoing wave are the same.

Pemerolehan Bahasa Kedua Menurut Stephen Krashen

Directory of Open Access Journals (Sweden)

Alif Cahya Setiyadi dan Mohammad Syam’un Salim

2013-12-01

Full Text Available Pada umumnya, pemerolehan bahasa kedua menurut para ahlibahasa semisal Noam Chomsky, memiliki arti kemustahilan, sebabmenurutnya pemeroleh bahasa hanya diperuntukkan pada bahasa pertama(ibu, tidak pada bahasa kedua. Tetapi Stephen Krashen malah berpikirsebaliknya; argumentasinya menyebutkan bahwa bahasa kedua mungkindiperoleh layaknya bahasa pertama. Bukan hanya kali itu saja Krashenberbeda pendapat dan berselisih, dari segi pembelajaran bahasa punStephen Krashen memiliki pendapat berseberangan dengan ahli bahasayang lain. Bila kebanyakan ahli bahasa mementingkan aturan bahasaGrammatical Rules pada saat belajar bahasa, Krashen malah menolaknya. Dimatanya, inti dari belajar bahasa adalah kemampuan untuk dapatberbicara dan berkomunikasi (communication bahasa tujuan.

Stephen Schwartz og den folkelige lyd

DEFF Research Database (Denmark)

Kreutzfeldt, Jacob

2013-01-01

Stephen Schwartz døde i foråret 2013. I denne artikel forsøger Jacob Kreutzfeldt, der gennemførte en række interviews med Schwartz gennem hans sidste år, at indkredse den æstetiske grundholdning, der prægede hans arbejde med radiomontagen i DR.......Stephen Schwartz døde i foråret 2013. I denne artikel forsøger Jacob Kreutzfeldt, der gennemførte en række interviews med Schwartz gennem hans sidste år, at indkredse den æstetiske grundholdning, der prægede hans arbejde med radiomontagen i DR....

Naked singularity, firewall, and Hawking radiation.

Science.gov (United States)

Zhang, Hongsheng

2017-06-21

Spacetime singularity has always been of interest since the proof of the Penrose-Hawking singularity theorem. Naked singularity naturally emerges from reasonable initial conditions in the collapsing process. A recent interesting approach in black hole information problem implies that we need a firewall to break the surplus entanglements among the Hawking photons. Classically, the firewall becomes a naked singularity. We find some vacuum analytical solutions in R n -gravity of the firewall-type and use these solutions as concrete models to study the naked singularities. By using standard quantum theory, we investigate the Hawking radiation emitted from the black holes with naked singularities. Here we show that the singularity itself does not destroy information. A unitary quantum theory works well around a firewall-type singularity. We discuss the validity of our result in general relativity. Further our result demonstrates that the temperature of the Hawking radiation still can be expressed in the form of the surface gravity divided by 2π. This indicates that a naked singularity may not compromise the Hakwing evaporation process.

Hawking radiation, the Stefan–Boltzmann law, and unitarization

Energy Technology Data Exchange (ETDEWEB)

Giddings, Steven B., E-mail: giddings@physics.ucsb.edu

2016-03-10

Where does Hawking radiation originate? A common picture is that it arises from excitations very near or at the horizon, and this viewpoint has supported the “firewall” argument and arguments for a key role for the UV-dependent entanglement entropy in describing the quantum mechanics of black holes. However, closer investigation of both the total emission rate and the stress tensor of Hawking radiation supports the statement that its source is a near-horizon quantum region, or “atmosphere,” whose radial extent is set by the horizon radius scale. This is potentially important, since Hawking radiation needs to be modified to restore unitarity, and a natural assumption is that the scales relevant to such modifications are comparable to those governing the Hawking radiation. Moreover, related discussion suggests a resolution to questions regarding extra energy flux in “nonviolent” scenarios, that does not spoil black hole thermodynamics as governed by the Bekenstein–Hawking entropy.

Hawking radiation, the Stefan–Boltzmann law, and unitarization

International Nuclear Information System (INIS)

Giddings, Steven B.

2016-01-01

Where does Hawking radiation originate? A common picture is that it arises from excitations very near or at the horizon, and this viewpoint has supported the “firewall” argument and arguments for a key role for the UV-dependent entanglement entropy in describing the quantum mechanics of black holes. However, closer investigation of both the total emission rate and the stress tensor of Hawking radiation supports the statement that its source is a near-horizon quantum region, or “atmosphere,” whose radial extent is set by the horizon radius scale. This is potentially important, since Hawking radiation needs to be modified to restore unitarity, and a natural assumption is that the scales relevant to such modifications are comparable to those governing the Hawking radiation. Moreover, related discussion suggests a resolution to questions regarding extra energy flux in “nonviolent” scenarios, that does not spoil black hole thermodynamics as governed by the Bekenstein–Hawking entropy.

Hawking radiation, the Stefan–Boltzmann law, and unitarization

Directory of Open Access Journals (Sweden)

Steven B. Giddings

2016-03-01

Full Text Available Where does Hawking radiation originate? A common picture is that it arises from excitations very near or at the horizon, and this viewpoint has supported the “firewall” argument and arguments for a key role for the UV-dependent entanglement entropy in describing the quantum mechanics of black holes. However, closer investigation of both the total emission rate and the stress tensor of Hawking radiation supports the statement that its source is a near-horizon quantum region, or “atmosphere,” whose radial extent is set by the horizon radius scale. This is potentially important, since Hawking radiation needs to be modified to restore unitarity, and a natural assumption is that the scales relevant to such modifications are comparable to those governing the Hawking radiation. Moreover, related discussion suggests a resolution to questions regarding extra energy flux in “nonviolent” scenarios, that does not spoil black hole thermodynamics as governed by the Bekenstein–Hawking entropy.

Blocking the Hawking radiation

DEFF Research Database (Denmark)

Autzen, M.; Kouvaris, C.

2014-01-01

grows after its formation (and eventually destroys the star) instead of evaporating. The fate of the black hole is dictated by the two opposite mechanics, i.e., accretion of nuclear matter from the center of the star and Hawking radiation that tends to decrease the mass of the black hole. We study how...... the assumptions for the accretion rate can in fact affect the critical mass beyond which a black hole always grows. We also study to what extent degenerate nuclear matter can impede Hawking radiation due to the fact that emitted particles can be Pauli blocked at the core of the star....

Thermodynamic Geometry and Hawking Radiation

CERN Document Server

Bellucci, S

2010-01-01

This work explores the role of thermodynamic fluctuations in the two parameter Hawking radiating black hole configurations. The system is characterized by an ensemble of arbitrary mass and radiation frequency of the black holes. In the due course of the Hawking radiations, we find that the intrinsic geometric description exhibits an intriguing set of exact pair correction functions and global correlation lengths. We investigate the nature of the constant amplitude radiation and find that it's not stable under fluctuations of the mass and frequency. Subsequently, the consideration of the York model decreasing amplitude radiation demonstrates that thermodynamic fluctuations are globally stable in the small frequency region. In connection with quantum gravity refinements, we take an account of the logarithmic correction into the constant amplitude and York amplitude over the Hawking radiation. In both considerations, we notice that the nature of the possible parametric fluctuations may precisely be ascertained w...

Fatal pox infection in a rough-legged hawk

Science.gov (United States)

Pearson, G.L.; Pass, D.A.; Beggs, E.C.

1975-01-01

Natural pox infection occurred in a free-living rough-legged hawk (Buteo lagopus) in northeastern North Dakota. Gross, histological and electron microscopic findings were typical of pox infection, and characteristic lesions developed in red-tailed hawks (Buteo jamaicensis) but not in great horned owls (Bubo virginianus) following inoculation with case material. Death of the rough-legged hawk was attributed to starvation resulting from inability to capture prey and to blood loss from foot lesions.

Hawk: A Runtime System for Partitioned Objects

NARCIS (Netherlands)

Ben Hassen, S.; Bal, H.E.; Tanenbaum, A.S.

1997-01-01

Hawk is a language-independent runtime system for writing data-parallel programs using partitioned objects. A partitioned object is a multidimensional array of elements that can be partitioned and distributed by the programmer. The Hawk runtime system uses the user-defined partitioning of objects

Ruzicka, Prof. Leopold Stephen

Indian Academy of Sciences (India)

Home; Fellowship. Fellow Profile. Elected: 1957 Honorary. Ruzicka, Prof. Leopold Stephen Nobel Laureate (Chemistry) - 1939. Date of birth: 13 September 1887. Date of death: 26 September 1976. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 January 2018. The 29th ...

Perfect simulation of Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Rasmussen, Jakob Gulddahl

This article concerns a perfect simulation algorithm for unmarked and marked Hawkes processes. The usual stratihtforward simulation algorithm suffers from edge effects, whereas our perfect simulation algorithm does not. By viewing Hawkes processes as Poisson cluster processes and using...... their branching and conditional independence structure, useful approximations of the distribution function for the length of a cluster are derived. This is used to construct upper and lower processes for the perfect simulation algorithm. Examples of applications and empirical results are presented....

Health evaluation of Galapagos Hawks (Buteo galapagoensis) on Santiago Island, Galapagos.

Science.gov (United States)

Deem, Sharon L; Rivera-Parra, Jose Luis; Parker, Patricia G

2012-01-01

Galapagos Hawks (Buteo galapagoensis), the only endemic, diurnal raptor species in Galapagos, are currently distributed on eight Galapagos Islands having been extirpated from three of the human-inhabited islands. In January 2009, we performed health assessments of 89 Galapagos Hawks on Santiago Island, Galapagos. Four of the 89 Galapagos Hawks (4%) evaluated had physical abnormalities. Blood parameters did not differ between males and females, except for aspartate transaminase values, which were significantly higher in females than males. No Galapagos Hawks tested positive for antibodies to avian encephalitis virus, Marek virus, and paramyxovirus-1 or to haemosporidian antigen. Chlamydophila psittaci antigen was detected in 2 of 86 Galapagos Hawks (2%), with 24 of 43 Galapagos Hawks (56%) antibody-positive for avian adenovirus-1 and 1 of 48 Galapagos Hawks (2%) antibody positive for Toxoplasma gondii. There were no significant differences in infectious disease results based on sex. This study contributes to the understanding of the health status of the Galapagos Hawk and to the establishment of baseline information for the species.

Recent trends in counts of migrant hawks from northeastern North America

Science.gov (United States)

Titus, K.; Fuller, M.R.

1990-01-01

Using simple regression, pooled-sites route-regression, and nonparametric rank-trend analyses, we evaluated trends in counts of hawks migrating past 6 eastern hawk lookouts from 1972 to 1987. The indexing variable was the total count for a season. Bald eagle (Haliaeetus leucocephalus), peregrine falcon (Falco peregrinus), merlin (F. columbarius), osprey (Pandion haliaetus), and Cooper's hawk (Accipiter cooperii) counts increased using route-regression and nonparametric methods (P 0.10). We found no consistent trends (P > 0.10) in counts of sharp-shinned hawks (A. striatus), northern goshawks (A. gentilis) red-shouldered hawks (Buteo lineatus), red-tailed hawks (B. jamaicensis), rough-legged hawsk (B. lagopus), and American kestrels (F. sparverius). Broad-winged hawk (B. platypterus) counts declined (P < 0.05) based on the route-regression method. Empirical comparisons of our results with those for well-studied species such as the peregrine falcon, bald eagle, and osprey indicated agreement with nesting surveys. We suggest that counts of migrant hawks are a useful and economical method for detecting long-term trends in species across regions, particularly for species that otherwise cannot be easily surveyed.

Distribution, density, and productivity of accipiter hawks breeding in Oregon

Science.gov (United States)

Richard T. Reynolds; Howard M. Wight

1978-01-01

Density of nests and productivity of Sharp-shinned Hawks (Accipiter striatus), Cooper's Hawks (A. cooperii), and Goshawks (A. gentilis) within Oregon are of interest because of recent declines of accipiter hawks in the eastern United States (Schriver 1969, Hackman and Henny 1971, Henny and Wight 1972). One...

Ward identities in the derivation of Hawking radiation from anomalies

International Nuclear Information System (INIS)

Umetsu, Koichiro

2008-01-01

Robinson and Wilczek suggested a new method of deriving Hawking radiation by the consideration of anomalies. The basic idea of their approach is that the flux of Hawking radiation is determined by anomaly cancellation conditions in the Schwarzschild black hole (BH) background. Iso et al. extended the method to a charged Reissner-Nordstroem BH and a rotating Kerr BH, and they showed that the flux of Hawking radiation can also be determined by anomaly cancellation conditions and regularity conditions of currents at the horizon. Their formulation gives the correct Hawking flux for all the cases at infinity and thus provides a new attractive method of understanding Hawking radiation. We present some arguments clarifying for this derivation. We show that the Ward identities and boundary conditions for covariant currents without referring to the Wess-Zumino terms and the effective action are sufficient to derive Hawking radiation. Our method, which does not use step functions, thus simplifies some of the technical aspects of the original formulation. (author)

Elementary Particles and the Forces of Nature

OpenAIRE

Hawking, Stephen W.

2017-01-01

Stephen W. Hawking, who was born in 1942 on the anniversary of Galileo’s death, holds Isaac Newton’s chair as Lucasian Professor of Mathematics at the University of Cambridge. Widely regarded as the most brilliant theoretical physicist since Einstein, he is also the author of Black Holes and Baby Universes, published in 1993, as well as numerous scientific papers and books.Посилання:Stephen W. Hawking, A Brief History of Time From the Big Bang to Black Holes, 1988.Kratkaja istorija vremeni. O...

Analogue Hawking radiation from astrophysical black-hole accretion

International Nuclear Information System (INIS)

Das, Tapas K

2004-01-01

We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass

No Hawking-Page phase transition in three dimensions

International Nuclear Information System (INIS)

Myung, Y.S.

2005-01-01

We investigate whether or not the Hawking-Page phase transition is possible to occur in three dimensions. Starting with the simplest class of Lanczos-Lovelock action, thermodynamic behavior of all AdS-type black holes without charge falls into two classes: Schwarzschild-AdS black holes in even dimensions and Chern-Simons black holes in odd dimensions. The former class can provide the Hawking-Page transition between Schwarzschild-AdS black holes and thermal AdS space. On the other hand, the latter class is exceptional and thus the Hawking-Page transition is hard to occur. In three dimensions, a second-order phase transition might occur between the non-rotating BTZ black hole and the massless BTZ black hole (thermal AdS space), instead of the first-order Hawking-Page transition between the non-rotating BTZ black hole and thermal AdS space

Observing Hawking radiation in Bose-Einstein condensates via correlation measurements

International Nuclear Information System (INIS)

Fabbri, A.

2013-01-01

Observing quantum particle creation by black holes (Hawking radiation) in the astrophysical context is, in ordinary situations, hopeless. Nevertheless the Hawking effect, which depends only on kinematical properties of wave propagation in the presence of horizons, is present also in the non gravitational contexts, for instance in stationary fluids undergoing supersonic flow. We present results on how to observe the analog Hawking radiation in Bose-Einstein condensates by a direct measurement of the density correlations due to the phonon pairs (Hawking-quanta– partner) created by the acoustic horizon.

Regional variation in diets of breeding Red-shouldered hawks

Science.gov (United States)

Strobel, Bradley N.; Boal, Clint W.

2010-01-01

We collected data on breeding season diet composition of Red-shouldered Hawks (Buteo lineatus) in south Texas and compared these data, and those reported from studies elsewhere to examine large scale spatial variation in prey use in eastern North America. Red-shouldered Hawk diets aligned into two significantly different groups, which appear to correlate with latitude. The diets of Red-shouldered Hawks in group 1, which are of more northern latitudes, had significantly more mammalian prey and significantly less amphibian prey than those in group 2, which are at more southerly latitudes. Our meta-analysis demonstrated the dietary flexibility of Red-shouldered Hawks, which likely accounts for their broad distribution by exploiting regional variations in taxon-specific prey availability.

Hawking radiation of black rings from anomalies

International Nuclear Information System (INIS)

Chen Bin; He Wei

2008-01-01

We derive Hawking radiation of five-dimensional black rings from gauge and gravitational anomalies using the method proposed by Robinson and Wilczek. We find, as in the black hole case, that the problem could reduce to a (1+1)-dimensional field theory and the anomalies result in correct Hawking temperature for neutral, dipole and charged black rings

Great Physicists - The Life and Times of Leading Physicists from Galileo to Hawking

Science.gov (United States)

Cropper, William H.

2004-09-01

Here is a lively history of modern physics, as seen through the lives of thirty men and women from the pantheon of physics. William H. Cropper vividly portrays the life and accomplishments of such giants as Galileo and Isaac Newton, Marie Curie and Ernest Rutherford, Albert Einstein and Niels Bohr, right up to contemporary figures such as Richard Feynman, Murray Gell-Mann, and Stephen Hawking. We meet scientists--all geniuses--who could be gregarious, aloof, unpretentious, friendly, dogged, imperious, generous to colleagues or contentious rivals. As Cropper captures their personalities, he also offers vivid portraits of their great moments of discovery, their bitter feuds, their relations with family and friends, their religious beliefs and education. In addition, Cropper has grouped these biographies by discipline--mechanics, thermodynamics, particle physics, and others--each section beginning with a historical overview. Thus in the section on quantum mechanics, readers can see how the work of Max Planck influenced Niels Bohr, and how Bohr in turn influenced Werner Heisenberg. Our understanding of the physical world has increased dramatically in the last four centuries. With Great Physicists , readers can retrace the footsteps of the men and women who led the way.

Hawking radiation due to photon and gravitino tunneling

International Nuclear Information System (INIS)

Majhi, Bibhas Ranjan; Samanta, Saurav

2010-01-01

Applying the Hamilton-Jacobi method we investigate the tunneling of photon across the event horizon of a static spherically symmetric black hole. The necessity of the gauge condition on the photon field, to derive the semiclassical Hawking temperature, is explicitly shown. Also, the tunneling of photon and gravitino beyond this semiclassical approximation are presented separately. Quantum corrections of the action for both cases are found to be proportional to the semiclassical contribution. Modifications to the Hawking temperature and Bekenstein-Hawking area law are thereby obtained. Using this corrected temperature and Hawking's periodicity argument, the modified metric for the Schwarzschild black hole is given. This corrected version of the metric, up to h order is equivalent to the metric obtained by including one loop back reaction effect. Finally, the coefficient of the leading order correction of entropy is shown to be related to the trace anomaly.

EURO HAWK Project Overview

National Research Council Canada - National Science Library

2003-01-01

Briefing charts from presentation on a EURO HAWK project overview; an airborne system with stand-off capability for wide-area intelligence, surveillance and reconnaissance meeting European NATO countries' ISR requirements...

Perfect simulation of Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Rasmussen, Jakob Gulddahl

2005-01-01

Our objective is to construct a perfect simulation algorithm for unmarked and marked Hawkes processes. The usual straightforward simulation algorithm suffers from edge effects, whereas our perfect simulation algorithm does not. By viewing Hawkes processes as Poisson cluster processes and using...... their branching and conditional independence structures, useful approximations of the distribution function for the length of a cluster are derived. This is used to construct upper and lower processes for the perfect simulation algorithm. A tail-lightness condition turns out to be of importance...... for the applicability of the perfect simulation algorithm. Examples of applications and empirical results are presented....

The Universe in a nutshell

CERN Document Server

Hawking, Stephen

2001-01-01

Stephen Hawking's A Brief History of Time was a publishing phenomenon. Translated into thirty languages, it has sold over nine million copies worldwide. It continues to captivate and inspire new readers every year. When it was first published in 1988 the ideas discussed in it were at the cutting edge of what was then known about the universe. In the intervening years there have been extraordinary advances in our understanding of the space and time. The technology for observing the micro- and macro-cosmic world has developed in leaps and bounds. During the same period cosmology and the theoretical sciences have entered a new golden age. Professor Stephen Hawking has been at the heart of this new scientific renaissance. Now, in The Universe in a Nutshell, Stephen Hawking brings us fully up-to-date with the advances in scientific thinking. We are now nearer than we have ever been to a full understanding of the universe. In a fascinating and accessible discussion that ranges from quantum mechanics, to time travel...

Hawking radiation of five-dimensional charged black holes with scalar fields

Directory of Open Access Journals (Sweden)

Yan-Gang Miao

2017-09-01

Full Text Available We investigate the Hawking radiation cascade from the five-dimensional charged black hole with a scalar field coupled to higher-order Euler densities in a conformally invariant manner. We give the semi-analytic calculation of greybody factors for the Hawking radiation. Our analysis shows that the Hawking radiation cascade from this five-dimensional black hole is extremely sparse. The charge enhances the sparsity of the Hawking radiation, while the conformally coupled scalar field reduces this sparsity.

Integrating Remote Sensing and Citizen Science to Study the Environmental Context and Ecological Consequences of Returning Avian Predators

Science.gov (United States)

Zuckerberg, B.; McCabe, J.; Yin, H.; Pidgeon, A. M.; Bonter, D. N.; Radeloff, V.

2017-12-01

Urbanization causes the simplification of animal communities dominated by exotic and invasive species with few top predators. In recent years, however, many animal predators (e.g., coyotes, cougars, and hawks) have become increasingly common in urban environments. As predator recovery is central to the mission of conservation biology, this colonization of urban environments represents a unique experiment in predator colonization and its associated ecological consequences. One such predator that is recovering from decades of widespread population declines are accipiter hawks. These woodland hawks are widely distributed throughout North America and are increasingly common in urban and suburban landscapes. Using data from Project FeederWatch, a national citizen science program, we quantified 25 years (1990-2015) of changes in the spatiotemporal dynamics of accipiter hawks in Washington D.C. and Chicago. We estimated change in hawk occupancy over time and identified the environmental characteristics associated with occupancy for two accipiter hawk species, Cooper's Hawk (Accipiter cooperii) and Sharp-shinned Hawk (Accipiter striatus), using Bayesian hierarchical models and remotely-sensed temperature (MODIS) and land cover data (NLCD). We found the proportion of sites recording the presence of accipiter hawks increased from 10% in the early 1990's to over 80% in 2015. This increase in occupancy followed a discrete pattern of establishment, growth, and saturation. Colonizing hawks were more strongly associated with remnant forest patches in urban environments. Over time, we found hawks became more tolerant of urban landscapes with higher amounts of impervious surface, suggesting that these predators became adapted to urbanization. The implications of returning predators and altered ecological dynamics in urban environments is of critical importance to conservation biology, and integrating remote sensing observations and citizen science allowed for an unprecedented

Hawking radiation from the cosmological horizon in a FRW universe

International Nuclear Information System (INIS)

Hu Yapeng

2011-01-01

It is well known that there is a Hawking radiation from the cosmological horizon of the de Sitter spacetime, and the de Sitter spacetime can be a special case of a FRW universe. Therefore, there may be a corresponding Hawking radiation in a FRW universe. Indeed, there have been several clues showing that there is a Hawking radiation from the apparent horizon of a FRW universe. In our Letter, however, we find that the Hawking radiation may come from the cosmological horizon. Moreover, we also find that the Hawking radiation from the apparent horizon of a FRW universe in some previous works can be a special case in our result, and the condition is that the variation rate of cosmological horizon r . H is zero. Note that, this condition is also consistent with the underlying integrable condition in these works from the apparent horizon.

Understanding Hawking radiation in the framework of open quantum systems

International Nuclear Information System (INIS)

Yu Hongwei; Zhang Jialin

2008-01-01

We study the Hawking radiation in the framework of open quantum systems by examining the time evolution of a detector (modeled by a two-level atom) interacting with vacuum massless scalar fields. The dynamics of the detector is governed by a master equation obtained by tracing over the field degrees of freedom from the complete system. The nonunitary effects are studied by analyzing the time behavior of a particular observable of the detector, i.e., its admissible state, in the Unruh, Hartle-Hawking, as well as Boulware vacua outside a Schwarzschild black hole. We find that the detector in both the Unruh and Hartle-Hawking vacua would spontaneously excite with a nonvanishing probability the same as what one would obtain if there is thermal radiation at the Hawking temperature from the black hole, thus reproducing the basic results concerning the Hawking effect in the framework of open quantum systems

NASA Global Hawk: A New Tool for Earth Science Research

Science.gov (United States)

Hall, Phill

2009-01-01

This slide presentation reviews the Global Hawk, a unmanned aerial vehicle (UAV) that NASA plans to use for Earth Sciences research. The Global Hawk is the world's first fully autonomous high-altitude, long-endurance aircraft, and is capable of conducting long duration missions. Plans are being made for the use of the aircraft on missions in the Arctic, Pacific and Western Atlantic Oceans. There are slides showing the Global Hawk Operations Center (GHOC), Flight Control and Air Traffic Control Communications Architecture, and Payload Integration and Accommodations on the Global Hawk. The first science campaign, planned for a study of the Pacific Ocean, is reviewed.

Hawking radiation in the Swiss-cheese universe

International Nuclear Information System (INIS)

Saida, Hiromi

2002-01-01

The Hawking radiation forms the essential basis of black-hole thermodynamics. Black-hole thermodynamics denotes a good correspondence between black-hole kinematics and the laws of ordinary thermodynamics, but has so far been considered only in an asymptotically flat case. Does such correspondence rely strongly on the feature of gravity vanishing at infinity? In order to resolve this question, extending the Hawking radiation to a case with a dynamical boundary condition like an expanding universe should be considered. Therefore, the Hawking radiation in an expanding universe is discussed in this paper. As a concrete model of a black hole in an expanding universe, we use the 'Swiss-cheese' universe which is a spacetime including a Schwarzschild black hole in the Friedmann-Robertson-Walker universe. Further, for simplicity, our calculation is performed in two dimensions. The resultant spectrum of the Hawking radiation measured by a comoving observer is generally different from a thermal one. We find that the qualitative behaviour of the non-thermal spectrum is of dumping oscillation as a function of the frequency measured by the observer, and that the intensity of the Hawking radiation is enhanced by the presence of a cosmological expansion. It is appropriate to say that a black hole with an asymptotically flat boundary condition stays in a lowest energy thermal equilibrium state, and that once a black hole is put into an expanding universe, it is excited to a non-equilibrium state and emits its mass energy with stronger intensity than a thermal one

Kindness in the Art Classroom: Kind Thoughts on Stephen Rowland

Science.gov (United States)

Lampert, Nancy

2011-01-01

This article is a response to Stephen Rowland's article, "Kindness," which appeared in "London Review of Education," November 2009. Much to my amazement, Stephen Rowland's article was the only one I found when I did a global database search on "kindness in education". I had thought that I would find reams of information in the databases on the…

Hawking temperature of constant curvature black holes

International Nuclear Information System (INIS)

Cai Ronggen; Myung, Yun Soo

2011-01-01

The constant curvature (CC) black holes are higher dimensional generalizations of Banados-Teitelboim-Zanelli black holes. It is known that these black holes have the unusual topology of M D-1 xS 1 , where D is the spacetime dimension and M D-1 stands for a conformal Minkowski spacetime in D-1 dimensions. The unusual topology and time-dependence for the exterior of these black holes cause some difficulties to derive their thermodynamic quantities. In this work, by using a globally embedding approach, we obtain the Hawking temperature of the CC black holes. We find that the Hawking temperature takes the same form when using both the static and global coordinates. Also, it is identical to the Gibbons-Hawking temperature of the boundary de Sitter spaces of these CC black holes.

A debate on open inflation

Science.gov (United States)

Hawking, S. W.

1999-07-01

This is a reproduction of Professor Stephen Hawking's part in a debate, which took place at the COSMO 98 Coference, in Monterey, California. Two other physicists, Andrei Linde and Alexander Villenkin, also took part. Professor Hawking is the Lucasian Professor of Mathematics at the University of Cambridge, in England.

75 FR 8742 - Notice of Inventory Completion: Stephen F. Austin State University, Nacogdoches, TX

Science.gov (United States)

2010-02-25

... DEPARTMENT OF THE INTERIOR National Park Service Notice of Inventory Completion: Stephen F. Austin... control of Stephen F. Austin State University, Nacogdoches, TX. The human remains and associated funerary..., which was under contract with Stephen F. Austin State University. In the early 1900s, human remains...

An Interview with Stephen Vitiello

Science.gov (United States)

Lampert, Nancy

2013-01-01

Stephen Vitiello is a world-renowned contemporary sound artist whom the author has known as a colleague for several years. This article presents an interview about the overall body of Vitiello's work to date, and his thoughts on teaching at Virginia Commonwealth University. The interview explores the creative and noncreative tensions between…

BOOK REVIEW: Meilensteine der Astronomie - Von Aristoteles bis Hawking

Science.gov (United States)

Duerbeck, H. W.; Hamel, J.

2006-12-01

A writer, more specific a writer on the history of astronomy, might from time to time look at the collected document folders with all the research material and reprints, and might wonder: has this been all? Especially at a time when recycling is in vogue? And, perhaps with a request or an invitation to submit something, he or she might consider re-using the material before its definitive disposal. Well, such are my feelings when I looked at Jurgen Hamel's new book Milestones of Astronomy - From Aristoteles to Hawking . A slight chance for survival of medium-sized publishers like Kosmos is to offer popular books, and a title must attract potential buyers: Aristoteles means the "old" times, and as concerns the "mad scientist" of modern times, Stephen Hawking has by now dethroned Einstein. In 1998, Hamel had published a Geschichte der Astronomie - Von den Anfangen bis zur Gegenwart (History of astronomy, from the beginnings to the present), which, of course, he could not simply copy. This time, he selected some stones from his research areas - milestones, touchstones, stumbling blocks in the long road of astronomical evolution - and put them between the covers of his new book. So let us look at these (mile)stones . The reader is informed about Aristoteles on 2 pages, but his medieval interpreter Johannes de Sacrobosco gets 8 pages! Copernicus' life and achievements are described on 9 pages, closely followed by his devotee and translator Rothmann with 8 pages; Copernicus' contemporary, Peter Apian, however, gets about 13! Bessel's and Herschel's lifes and works are described on well-deserved 13 and 15 pages, while the achievements of the two Lucasian professors, Isaac Newton and Stephen Hawking, are just outlined in a single paragraph! Thus, importance is sometimes inversely proportional to text length... But let us become serious now. Why should an active historian outline, for the hundreth time, the life of Copernicus, while there are so many interesting, and often

Laparoscopic Stephen-Fowler stage procedure: appropriate management for high intra-abdominal testes.

Science.gov (United States)

Agrawal, Amit; Joshi, Milind; Mishra, Pankaj; Gupta, Rahul; Sanghvi, Beejal; Parelkar, Sandesh

2010-03-01

The length of testicular vessels is the main length-limiting factor to bring down the testes in the scrotum. Fowler and Stephen proposed the division of testicular vessels, high and as far from the testes as possible to maintain collateral blood supply, to treat high intra-abdominal testes. Cortesi introduced the diagnostic laparoscopy and Jorden first did the laparoscopic orchiopexy for nonpalpable testes. We had done Fowler-Stephen staged orchiopexy for high intra-abdominal testes, in which both stages were done laparoscopically. In total, 17 testes of 13 patients had undergone laparoscopic staged Fowler-Stephen orchiopexy. The decision to perform a staged Fowler-Stephen orchiopexy was based on the distance of the testis from the deep inguinal ring on laparoscopy. If distance was more than 2.5 cm, then we proceeded to a laparoscopic staged Fowler-Stephen orchiopexy. In the first stage, testicular vessels were cauterized by bipolar diathermy. Laparoscopic second-stage Fowler-Stephen procedure was done 6 months after the first stage. Patients were regularly followed, and the success of the procedure was assessed by the size of the testes and the position in the scrotum. Testicular vascularity was assessed by color Doppler ultrasonography. There was no testicular atrophy on second stage and on follow-up. All testes were in the scrotum with good size on follow-up. There was no complication related to laparoscopy. In cases of high intra-abdominal testes, the staged Fowler-Stephen procedure should be the procedure of choice. This procedure yields a high success rate. Transaction of vessels by bipolar diathermy is a very safe, cost-effective method.

Stephen Myers - More collaboration for accelerators

CERN Multimedia

2009-01-01

Stephen Myers has been appointed Director of Accelerators and Technology. His highest priority is to get the LHC running this year, but beyond that he also has the difficult task of balancing resources between non-LHC physics, new projects and consolidation of the existing accelerators. Stephen Myers, previous head of the Accelerator and Beams (AB) Department, will now oversee all the accelerator and technology activities at CERN, including the Beams, Technology and Engineering departments, in the re-established position of Director of Accelerators and Technology. "There are several good reasons to have a single person responsible for the CERN accelerators and technology," said Myers. "Most importantly, this will allow closer collaboration between the three departments and provide the structure for possible redeployment of resources. There will, of course, be regular meetings between the heads of department and myself, and if proble...

Hawking radiation inside a Schwarzschild black hole

Science.gov (United States)

Hamilton, Andrew J. S.

2018-05-01

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 character of the Hawking radiation, coupled with conservation of energy-momentum, the trace anomaly, and the familiar behavior of Hawking radiation far from the black hole, leads to a complete description of the quantum energy-momentum inside a Schwarzschild black hole. The quantum energy-momentum near the singularity diverges as r^{-6}, and consists of relativistic Hawking radiation and negative energy vacuum in the ratio 3 : - 2. The classical back reaction of the quantum energy-momentum on the geometry, calculated using the Einstein equations, serves merely to exacerbate the singularity. All the results are consistent with traditional calculations of the quantum energy-momentum in 1 + 1 spacetime dimensions.

Higher curvature self-interaction corrections to Hawking radiation

Science.gov (United States)

Fairoos, C.; Sarkar, Sudipta; Yogendran, K. P.

2017-07-01

The purely thermal nature of Hawking radiation from evaporating black holes leads to the information loss paradox. A possible route to its resolution could be if (enough) correlations are shown to be present in the radiation emitted from evaporating black holes. A reanalysis of Hawking's derivation including the effects of self-interactions in general relativity shows that the emitted radiation does deviate from pure thermality; however no correlations exist between successively emitted Hawking quanta. We extend the calculations to Einstein-Gauss-Bonnet gravity and investigate if higher curvature corrections to the action lead to some new correlations in the Hawking spectra. The effective trajectory of a massless shell is determined by solving the constraint equations and the semiclassical tunneling probability is calculated. As in the case of general relativity, the radiation is no longer thermal and there is no correlation between successive emissions. The absence of any extra correlations in the emitted radiations even in Gauss-Bonnet gravity suggests that the resolution of the paradox is beyond the scope of semiclassical gravity.

Stephen Hanseni kammerlikum pool / Ülle Hallik

Index Scriptorium Estoniae

Hallik, Ülle, 1963-

2007-01-01

Norra tenori Stephen Hanseni soolokontsertidest "The Sound of Musicals" 22.-23. Vanemuise suures majas, 29. sept. Jõhvi kontserdimajas, 30. sept. Pärnu kontserdimajas ja 7. okt. Estonia kontserdisaalis

What the White "Squaws" Want from Black Hawk: Gendering the Fan-Celebrity Relationship

Science.gov (United States)

Helton, Tena L.

2010-01-01

Americans in the East were great fans of Black Hawk, whose popularity on tour overtook that of Andrew Jackson's parallel tour of the Northeast. Undoubtedly, then, Black Hawk was a celebrity. He remained popular even in 1837, when he attended Catlin's gallery opening in New York, which included his 1832 painting of Black Hawk. Black Hawk may also…

Approximate simulation of Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Rasmussen, Jakob Gulddahl

2006-01-01

Hawkes processes are important in point process theory and its applications, and simulation of such processes are often needed for various statistical purposes. This article concerns a simulation algorithm for unmarked and marked Hawkes processes, exploiting that the process can be constructed...... as a Poisson cluster process. The algorithm suffers from edge effects but is much faster than the perfect simulation algorithm introduced in our previous work Møller and Rasmussen (2004). We derive various useful measures for the error committed when using the algorithm, and we discuss various empirical...... results for the algorithm compared with perfect simulations. Extensions of the algorithm and the results to more general types of marked point processes are also discussed....

Hawking radiation of a vector field and gravitational anomalies

International Nuclear Information System (INIS)

Murata, Keiju; Miyamoto, Umpei

2007-01-01

Recently, the relation between Hawking radiation and gravitational anomalies has been used to estimate the flux of Hawking radiation for a large class of black objects. In this paper, we extend the formalism, originally proposed by Robinson and Wilczek, to the Hawking radiation of vector particles (photons). It is explicitly shown, with the Hamiltonian formalism, that the theory of an electromagnetic field on d-dimensional spherical black holes reduces to one of an infinite number of massive complex scalar fields on 2-dimensional spacetime, for which the usual anomaly-cancellation method is available. It is found that the total energy emitted from the horizon for the electromagnetic field is just (d-2) times that for a scalar field. The results support the picture that Hawking radiation can be regarded as an anomaly eliminator on horizons. Possible extensions and applications of the analysis are discussed

Influence of poisoned prey on foraging behavior of ferruginous hawks

Science.gov (United States)

Vyas, Nimish B.; Kuncir, Frank; Clinton, Criss C.

2017-01-01

We recorded 19 visits by ferruginous hawks (Buteo regalis) over 6 d at two black–tailed prairie dog (Cynomys ludovicianus) subcolonies poisoned with the rodenticide Rozol® Prairie Dog Bait (0.005% chlorophacinone active ingredient) and at an adjacent untreated subcolony. Before Rozol® application ferruginous hawks foraged in the untreated and treated subcolonies but after Rozol® application predation by ferruginous hawks was only observed in the treated subcolonies. We suggest that ferruginous hawks' preference for hunting in the treated subcolonies after Rozol® application was influenced by the availability of easy-to-capture prey, presumably due to Rozol® poisoning. The energetically beneficial behavior of favoring substandard prey may increase raptor encounters with rodenticide exposed animals if prey vulnerability has resulted from poisoning.

Modulated Hawking radiation and a nonviolent channel for information release

OpenAIRE

Giddings, Steven B.

2014-01-01

Unitarization of black hole evaporation requires that quantum information escapes a black hole; an important question is to identify the mechanism or channel by which it does so. Accurate counting of black hole states via the Bekenstein–Hawking entropy would indicate this information should be encoded in radiation with average energy flux matching Hawking's. Information can be encoded with no change in net flux via fine-grained modulation of the Hawking radiation. In an approximate effective ...

Comments from physicsworld.com

Science.gov (United States)

2010-10-01

Oh, God. Yes, the debate about science and religion has kicked off once again, this time thanks to Stephen Hawking and Leonard Mlodinow's new book The Grand Design (2 September "God and the god particle"; 3 September "Talking Hawking and God"; 8 September "M-theory, religion and science funding on the BBC").

A brief history of time a reader's companion

CERN Document Server

1992-01-01

In 1989 Anglia Television joined with Steven Spielberg's Amblin Entertainment, NBC and the Tokyo Broadcasting System to announce production of a 90-minute feature on the life of Stephen Hawking and his book "A Brief History of Time". The film that resulted highlights the visual demonstration of Hawking's theories and this book provides an accompaniment to this film as well as a biography of Hawking's life, including his battle against motor neurone disease.

Reading Stephen King: Issues of Censorship, Student Choice, and Popular Literature.

Science.gov (United States)

Power, Brenda Miller, Ed.; Wilhelm, Jeffrey D., Ed.; Chandler, Kelly, Ed.

This collection of essays grew out of the "Reading Stephen King Conference" held at the University of Maine in 1996. Stephen King's books have become a lightning rod for the tensions around issues of including "mass market" popular literature in middle and high school English classes and of who chooses what students read.…

Extraocular muscle architecture in hawks and owls.

Science.gov (United States)

Plochocki, Jeffrey H; Segev, Tamar; Grow, Wade; Hall, Margaret I

2018-02-06

A complete and accurate understanding of extraocular muscle function is important to the veterinary care of the avian eye. This is especially true for birds of prey, which rely heavily on vision for survival and yet are prone to ocular injury and disease. To better understand the function of extraocular muscles in birds of prey, we studied extraocular muscle architecture grossly and histologically. This sample was composed of two each of the following species: red-tailed hawk (Buteo jamaicensis), Harris's hawk (Parabuteo unicinctus), great horned owl (Bubo virginianus), and barn owl (Tyto alba). All extraocular muscles were dissected and weighed. To analyze muscle fiber architecture, the superior oblique and quadratus muscles were dissected, weighed, and sectioned at 5 μm thickness in the transverse plane. We calculated the physiologic cross-sectional area and the ratio of muscle mass to predicted effective maximum tetanic tension. Hawk and owl extraocular muscles exhibit significant physiological differences that play roles in ocular movements and closure of the nictitating membrane. Owls, which do not exhibit extraocular movement, have muscle architecture suited to stabilize the position of a massive, tubular eye that protrudes significantly from the orbit. Hawks, which have a more globose eye that is largely contained within the orbit, do not require as much muscular stability and instead have muscle architecture that facilitates rapid eye movement. © 2018 American College of Veterinary Ophthalmologists.

Spizaetus hawk-eagles as predators of arboreal colobines.

Science.gov (United States)

Fam, S D; Nijman, V

2011-04-01

The predation pressure put on primates by diurnal birds of prey differs greatly between continents. Africa and South America have specialist raptors (e.g. crowned hawk-eagle Stephanoaetus coronatus and harpy eagle Harpia harpyja) whereas in Asia the only such specialist's (Philippine eagle Pithecophaga jefferyi) distribution is largely allopatric with primates. The almost universal absence of polyspecific groups in Asia (common in Africa and South America) may indicate reduced predation pressure. As such there is almost no information on predation pressures on primates in Asia by raptors. Here we report successful predation of a juvenile banded langur Presbytis femoralis (~2 kg) by a changeable hawk-eagle Spizaetus cirrhatus. The troop that was attacked displayed no signs of being alarmed, and no calls were made before the event. We argue that in insular Southeast Asia, especially, large Spizaetus hawk-eagles (~2 kg) are significant predators of arboreal colobines. Using data on the relative size of sympatric Spizaetus hawk-eagles and colobines we make predictions on where geographically we can expect the highest predation pressure (Thai-Malay Peninsula) and which colobines are least (Nasalis larvatus, Trachypithecus auratus, P. thomasi) and most (P. femoralis, T. cristatus) affected.

Origin of Hawking radiation

International Nuclear Information System (INIS)

Hajicek, P.

1987-01-01

In the first part of the paper, the possible influence that quantum corrections could have on the existence and position of an event horizon in a spherically symmetric collapse is studied. A counterexample is constructed proving that the small value of near the gravitational radius does not guarantee the formation of an event horizon. In an exactly solvable model of black-hole evaporation, the spacetime structure is manipulated in the Planck neighborhood of the singularity so that the event horizon is shifted arbitrarily to the future or removed completely. This change in the position of the event horizon has no observable consequences until the retarded time of the end of the black-hole evaporation is reached. However, even in the absence of the event horizon, the Hawking radiation survives. In the second part of the paper, its origin is studied. The old idea is adopted that it is coming from a neighborhood of the so-called ergosphere. The concept of the ergosphere is generalized to nonstationary, spherically symmetric spacetimes using the notion of Hawking quasilocal mass. The boundary of such an ergosphere is shown to coincide with the locus of apparent horizons. It seems, therefore, that the Hawking effect is associated with the apparent rather than the event horizon. An extrapolation of some properties of from a neighborhood of the Schwarzschild horizon to that of an apparent horizon forming in a collapse leads to the result that too much energy is radiated away already before the apparent horizon forms, similarly as in the Boulware scenario of gravitational collapse

Characterization of Sarcocystis from four species of hawks from Georgia, USA.

Science.gov (United States)

Yabsley, Michael J; Ellis, Angela E; Stallknecht, David E; Howerth, Elizabeth W

2009-02-01

During 2001 to 2004, 4 species of hawks (Buteo and Accipiter spp.) from Georgia were surveyed for Sarcocystis spp. infections by examining intestinal sections. In total, 159 of 238 (66.8%) hawks examined were infected with Sarcocystis spp. Samples from 10 birds were characterized by sequence analysis of a portion of the 18S rRNA gene (783 base pairs). Only 3 of the 10 sequences from the hawks were identical; the remainder differed by at least 1 nucleotide. Phylogenetic analysis failed to resolve the position of the hawk Sarcocystis species, but they were closely related several Sarcocystis species from raptors, rodents, and Sarcocystis neurona. The high genetic diversity of Sarcocystis suggests that more than 1 species infects these 4 hawk species; however, additional molecular or experimental work will be required to determine the speciation and diversity of parasites infecting these avian hosts. In addition to assisting with determining species richness of Sarcocystis in raptors, molecular analysis should be useful in the identification of potential intermediate hosts.

75 FR 49994 - James Stephen Ferguson, D.M.D.; Revocation of Registration

Science.gov (United States)

2010-08-16

... DEPARTMENT OF JUSTICE Drug Enforcement Administration [Docket No. 09-64] James Stephen Ferguson, D.M.D.; Revocation of Registration On July 24, 2009, the Deputy Assistant Administrator, Office of Diversion Control, Drug Enforcement Administration (DEA), issued an Order to Show Cause to James Stephen...

Hawking Temperature of Acoustic Black Hole Zhi Kun Xie

Indian Academy of Sciences (India)

Abstract. Using a new tortoise coordinate transformation, the Hawking radiation of the acoustic black hole was discussed by studying the Klein–. Gordon equation of scalar particles in the curve space-time. It was found that the Hawking temperature is connected with time and position on the event horizon. Key words.

Hawking Temperature of an Arbitrarily Accelerating Black Hole Wei ...

Indian Academy of Sciences (India)

Introduction. In 1974, Hawking (1974) made a striking discovery that black holes could produce thermal radiation. In this paper, we will obtain Hawking temperature of an arbitrarily accelerating black hole based on the Klein–Gordon equation, which is identical to the one obtained by the Hamilton–Jacobi equation under the ...

Hawking radiation from AdS black holes

International Nuclear Information System (INIS)

Hubeny, Veronika E; Rangamani, Mukund; Marolf, Donald

2010-01-01

We study Hartle-Hawking-like states of quantum field theories on asymptotically AdS black hole backgrounds, with particular regard to the phase structure of interacting theories. By a suitable analytic continuation we show that the equilibrium dynamics of field theories on large asymptotically AdS black holes can be related to the low-temperature states of the same field theory on the AdS soliton (or pure AdS) background. This allows us to gain insight into Hartle-Hawking-like states on large-radius Schwarzschild- or rotating-AdS black holes. Furthermore, we exploit the AdS/CFT correspondence to explore the physics of strongly coupled large N theories on asymptotically AdS black holes. In particular, we exhibit a plausibly complete set of phases for the M2-brane world-volume superconformal field theory on a BTZ black hole background. Our analysis partially resolves puzzles previously raised in connection with Hawking radiation on large AdS black holes.

Hawking radiation of an apparent horizon in a FRW universe

International Nuclear Information System (INIS)

Cai Ronggen; Cao Liming; Hu Yapeng

2009-01-01

Hawking radiation is an important quantum phenomenon of a black hole, which is closely related to the existence of an event horizon of a black hole. The cosmological event horizon of de Sitter space is also of Hawking radiation with a thermal spectrum. By use of the tunneling approach, we show that there is indeed a Hawking radiation with temperature, T=1/(2πr-tilde A , for a locally defined apparent horizon of a Friedmann-Robertson-Walker universe with any spatial curvature, where r-tilde A is the apparent horizon radius. Thus we fill in the gap existing in the literature investigating the relation between the first law of thermodynamics and Friedmann equations; there the apparent horizon is assumed to have such a temperature without any proof. In addition, we stress the implication of the Hawking temperature associated with the apparent horizon.

Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?

International Nuclear Information System (INIS)

Mersini-Houghton, Laura

2014-01-01

Particle creation leading to Hawking radiation is produced by the changing gravitational field of the collapsing star. The two main initial conditions in the far past placed on the quantum field from which particles arise, are the Hartle–Hawking vacuum and the Unruh vacuum. The former leads to a time-symmetric thermal bath of radiation, while the latter to a flux of radiation coming out of the collapsing star. The energy of Hawking radiation in the interior of the collapsing star is negative and equal in magnitude to its value at future infinity. This work investigates the backreaction of Hawking radiation on the interior of a gravitationally collapsing star, in a Hartle–Hawking initial vacuum. It shows that due to the negative energy Hawking radiation in the interior, the collapse of the star stops at a finite radius, before the singularity and the event horizon of a black hole have a chance to form. That is, the star bounces instead of collapsing to a black hole. A trapped surface near the last stage of the star's collapse to its minimum size may still exist temporarily. Its formation depends on the details of collapse. Results for the case of Hawking flux of radiation with the Unruh initial state, will be given in a companion paper II

Stephen K. Robinson arrives at KSC for the STS-95 launch

Science.gov (United States)

1998-01-01

STS-95 Mission Specialist Stephen K. Robinson, arrives at Kennedy Space Center's Shuttle Landing Facility aboard a T-38 jet as part of final preparations for launch. The STS-95 mission, targeted for liftoff at 2 p.m. on Oct. 29, includes research payloads such as the Spartan solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as the SPACEHAB single module with experiments on space flight and the aging process. The mission is expected to last 8 days, 21 hours and 49 minutes, and return to KSC on Nov. 7. The other STS-95 crew members are Mission Commander Curtis L. Brown Jr., Pilot Steven W. Lindsey, Mission Specialist Scott E. Parazynski, Payload Specialist John H. Glenn Jr., senator from Ohio, Mission Specialist Pedro Duque, with the European Space Agency (ESA), and Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA).

Physics and philanthropy

Science.gov (United States)

Whitworth, Leila; Ragtime; Nolowerboundonsize; Quandry12

2014-05-01

In reply to the news story “Cambridge physicists divided over Hawking chair” (April p12, http://ow.ly/vyLil) about the university's new Stephen W Hawking Professorship, which must, according to its philanthropic funders, have an associated salary “equal to or greater than the average” for other professorships of similar rank in the department.

Minimal conditions for the existence of a Hawking-like flux

International Nuclear Information System (INIS)

Barcelo, Carlos; Liberati, Stefano; Sonego, Sebastiano; Visser, Matt

2011-01-01

We investigate the minimal conditions that an asymptotically flat general relativistic spacetime must satisfy in order for a Hawking-like Planckian flux of particles to arrive at future null infinity. We demonstrate that there is no requirement that any sort of horizon form anywhere in the spacetime. We find that the irreducible core requirement is encoded in an approximately exponential 'peeling' relationship between affine coordinates on past and future null infinity. As long as a suitable adiabaticity condition holds, then a Planck-distributed Hawking-like flux will arrive at future null infinity with temperature determined by the e-folding properties of the outgoing null geodesics. The temperature of the Hawking-like flux can slowly evolve as a function of time. We also show that the notion of peeling of null geodesics is distinct from the usual notion of 'inaffinity' used in Hawking's definition of surface gravity.

A 38-year Summary of Raptor Banding at Hawk Ridge, Duluth, Minnesota, USA

Science.gov (United States)

Consistent banding of raptors at Hawk Ridge was initiated in 1972 and has continued for 38 years to the present. A total of 99,505 raptors or 2,619 per year have been banded at Hawk Ridge including 23 different species. The majority of birds banded were Sharp-shinned Hawks (Acci...

Hawking radiation of Dirac particles from the Myers-Perry black hole

International Nuclear Information System (INIS)

Mao, Pu-Jian; Jia, Lin-Yu; Li, Ran; Ren, Ji-Rong

2011-01-01

In this paper, we apply the quantum anomaly cancelation method and the effective action approach as well as the method of Damour-Ruffini-Sannan to derive Hawking radiation of Dirac particles from the Myers-Perry black hole. Using the dimensional reduction technique, we find that the fermionic field in the background of the Myers-Perry black hole can be treated as an infinite collection of quantum fields in (1+1)-dimensional background coupled with the dilaton field and the U(1) gauge field near the horizon. Thus Hawking temperature and fluxes are found. The Hawking temperature obtained agrees with the surface gravity formula while the Hawking fluxes derived from the anomaly cancelation method and the effective action approach are in complete agreement with the ones obtained from integrating the Planck distribution. (orig.)

Low-frequency analogue Hawking radiation: The Bogoliubov-de Gennes model

Science.gov (United States)

Coutant, Antonin; Weinfurtner, Silke

2018-01-01

We analytically study the low-frequency properties of the analogue Hawking effect in Bose-Einstein condensates. We show that in one-dimensional flows displaying an analogue horizon, the Hawking effect is dominant in the low-frequency regime. This happens despite nonvanishing grey-body factors, that is, the coupling of the Hawking mode and its partner to the mode propagating with the flow. To show this, we obtained analytical expressions for the scattering coefficients, in general flows and taking into account the full Bogoliubov dispersion relation. We discuss the obtained expressions for the grey-body factors. In particular, we show that they can be significantly decreased if the flow obeys a conformal coupling condition. We argue that in the presence of a small but non-zero temperature, reducing grey-body factors greatly facilitates the observation of entanglement, that is, establishing that the state of the Hawking mode and its partner is non-separable.

Hawking fluxes and anomalies in rotating regular black holes with a time-delay

International Nuclear Information System (INIS)

Takeuchi, Shingo

2016-01-01

Based on the anomaly cancellation method we compute the Hawking fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor) from a four-dimensional rotating regular black hole with a time-delay. To this purpose, in the three metrics proposed in [1], we try to perform the dimensional reduction in which the anomaly cancellation method is feasible at the near-horizon region in a general scalar field theory. As a result we can demonstrate that the dimensional reduction is possible in two of those metrics. Hence we perform the anomaly cancellation method and compute the Hawking fluxes in those two metrics. Our Hawking fluxes involve three effects: (1) quantum gravity effect regularizing the core of the black holes, (2) rotation of the black hole, (3) time-delay. Further in this paper toward the metric in which the dimensional could not be performed, we argue that it would be some problematic metric, and mention its cause. The Hawking fluxes we compute in this study could be considered to correspond to more realistic Hawking fluxes. Further what Hawking fluxes can be obtained from the anomaly cancellation method would be interesting in terms of the relation between a consistency of quantum field theories and black hole thermodynamics. (paper)

The Stephen F. Austin Experimental Forest

Science.gov (United States)

Cary C. Russell; Ronald E. Thill; David L. Kulhavy

2002-01-01

On December 14, 1944, the Seventy-Eighth United States Congress passed a bill that authorized the transfer of 2,560 acres in Nacogdoches County, Texas, to the research branch of the United States Forest Service (USFS). This land became the Stephen F. Austin Experimental Forest (SFAEF) on September 19. 1945. One of eighty-one federal experimental forests and ranges...

Four-center bubbled BPS solutions with a Gibbons-Hawking base

Science.gov (United States)

Heidmann, Pierre

2017-10-01

We construct four-center bubbled BPS solutions with a Gibbons-Hawking base space. We give a systematic procedure to build scaling solutions: starting from three-supertube configurations and using generalized spectral flows and gauge transformations to extend to solutions with four Gibbons-Hawking centers. This allows us to construct very large families of smooth horizonless solutions that have the same charges and angular momentum as supersymmetric black holes with a macroscopically large horizon area. Our construction reveals that all scaling solutions with four Gibbons Hawking centers have an angular momentum at around 99% of the cosmic censorship bound. We give both an analytical and a numerical explanation for this unexpected feature.

MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON'S HAWKS.

Science.gov (United States)

Kochert, Michael N; Fuller, Mark R; Schueck, Linda S; Bond, Laura; Bechard, Marc J; Woodbridge, Brian; Holroyd, Geoff; Martell, Mark; Banasch, Ursula

From 1995-1998, we tracked movements of adult Swainson's Hawks ( Buteo swainsoni ) using satellite telemetry to characterize migration, important stopover areas, and austral summer movements. We tagged 46 hawks from July - September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson's Hawks basically followed three routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal austral summer area in central Argentina. North of 20° N, southward and northward tracks differed little for individuals from east of the Continental Divide but differed greatly (up to 1700 km) for individuals from west of the Continental Divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. South migration lasted 42 to 98 days, and north migration took 51 to 82 days. On south migration, 36% of the Swainson's Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio marked hawks and made stopovers 9.0 - 26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The austral period lasted 76 to 128 days. All Swainson's Hawks used a core area in central Argentina within 23% of the 738800 km 2 austral summer range where they frequently moved long distances (up to 1600 km). Conservation of Swainson's Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons including migration stopovers.

Hawking radiation, the Stefan-Boltzmann law, and unitarization

OpenAIRE

Giddings, Steven B.

2015-01-01

Where does Hawking radiation originate? A common picture is that it arises from excitations very near or at the horizon, and this viewpoint has supported the “firewall” argument and arguments for a key role for the UV-dependent entanglement entropy in describing the quantum mechanics of black holes. However, closer investigation of both the total emission rate and the stress tensor of Hawking radiation supports the statement that its source is a near-horizon quantum region, or “atmosphere,” w...

New coordinates for BTZ black hole and Hawking radiation via tunnelling

International Nuclear Information System (INIS)

Liu Wenbiao

2006-01-01

Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. For the stationary axisymmetric BTZ black hole, a generalized Painleve coordinate system (Painleve-BTZ coordinates) is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is obtained which is not precise thermal spectrum. The result is consistent with the underlying unitary theory. Moreover, Bekenstein-Hawking entropy of BTZ black hole is not necessarily corrected when we choose appropriate coordinate system to study the tunnelling effect

Black hole in a waveguide: Hawking radiation or self-phase modulation?

International Nuclear Information System (INIS)

Smolyaninov, Igor I

2015-01-01

Recently it was suggested that Hawking radiation may be observed in a nonlinear electromagnetic waveguide upon propagation of an optical pulse. We show that the spectral characteristics of the Hawking effect in such a waveguide are indistinguishable from the well-known effect of frequency broadening of an optical pulse due to self-phase modulation. Furthermore, we derive an estimate on the critical optical power at which Hawking effect is dominated by the self-phase modulation. It appears that optical experiments reported so far are clearly dominated by self-phase modulation. (paper)

Connecting anomaly and tunneling methods for the Hawking effect through chirality

International Nuclear Information System (INIS)

Banerjee, Rabin; Majhi, Bibhas Ranjan

2009-01-01

The role of chirality is discussed in unifying the anomaly and the tunneling formalisms for deriving the Hawking effect. Using the chirality condition and starting from the familiar form of the trace anomaly, the chiral (gravitational) anomaly, manifested as a nonconservation of the stress tensor, near the horizon of a black hole, is derived. Solution of this equation yields the stress tensor whose asymptotic infinity limit gives the Hawking flux. Finally, use of the same chirality condition in the tunneling formalism gives the Hawking temperature that is compatible with the flux obtained by anomaly method.

Low prevalence of Trichomonas gallinae in urban and migratory Cooper's Hawks in northcentral North America

Science.gov (United States)

Rosenfield, Robert N.; Taft, Stephen J.; Stout, William E.; Driscoll, Timothy G.; Evans, David L.; Bozek, Michael A.

2009-01-01

Trichomoniasis is a digestive tract disease caused by ingestion of the protozoan Trichomonas gallinae. This disease can be a significant source of mortality. No deaths of nestlings could be attributed to trichomoniasis in Cooper's Hawks (Accipiter cooperii) breeding in urban and rural environs in Wisconsin, North Dakota, and British Columbia. We detected T. gallinae in four (5.2%) of 77 nestling Cooper's Hawks during 2006 and 2007 among 42 urban nests on new study areas in southeast Wisconsin and eastern North Dakota/western Minnesota. All four infected young fledged. We did not detect T. gallinae in 52 breeding adult Cooper's Hawks on two urban study sites, nor in 28 migrant hatching year (n  =  24) and adult (n  =  4) Cooper's Hawks at Hawk Ridge Nature Reserve, Duluth, Minnesota in 2006–2007. Overall, we detected T. gallinae in only 2.5% of 157 Cooper's Hawks in northcentral North America. These results suggest a low prevalence of T. gallinae in Cooper's Hawks in the northern part of this hawk's breeding range.

Hawking radiation from dilatonic black holes via anomalies

International Nuclear Information System (INIS)

Jiang Qingquan; Cai Xu; Wu Shuangqing

2007-01-01

Recently, Hawking radiation from a Schwarzschild-type black hole via a gravitational anomaly at the horizon has been derived by Robinson and Wilczek. Their result shows that, in order to demand general coordinate covariance at the quantum level to hold in the effective theory, the flux of the energy-momentum tensor required to cancel the gravitational anomaly at the horizon of the black hole is exactly equal to that of (1+1)-dimensional blackbody radiation at the Hawking temperature. In this paper, we attempt to apply the analysis to derive Hawking radiation from the event horizons of static, spherically symmetric dilatonic black holes with arbitrary coupling constant α, and that from the rotating Kaluza-Klein (α=√(3)) as well as the Kerr-Sen (α=1) black holes via an anomalous point of view. Our results support Robinson and Wilczek's opinion. In addition, the properties of the obtained physical quantities near the extreme limit are qualitatively discussed

'Splendeurs et miseres' of Hawking's effect

Energy Technology Data Exchange (ETDEWEB)

Hajicek, P [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik

1977-01-01

The paper deals with the emission of particles from a black hole, in particular Hawking's effect. Quantum field theory is applied in curved space-time. Spherically symmetrical gravitational collapse is considered.

Official portrait of astronaut Stephen S. Oswald

Science.gov (United States)

1992-01-01

Official portrait of astronaut Stephen S. Oswald. Oswald, a member of Astronaut Class 11, wears launch and entry suit (LES) with launch and entry helmet (LEH) positioned at his side. In the background is the United States (U.S.) flag and a space shuttle orbiter model.

Comparative Studies on Bioactive Constituents in Hawk Tea Infusions with Different Maturity Degree and Their Antioxidant Activities

Directory of Open Access Journals (Sweden)

Ming Yuan

2014-01-01

Full Text Available Hawk tea (Litsea coreana var. lanuginose is a very popular herbal tea in the southwest of China. According to the maturity degree of raw materials, Hawk tea can usually be divided into three types: Hawk bud tea (HB, Hawk primary leaf tea (HP, and Hawk mature leaf tea (HM. In this study, some of the bioactive constituents and antioxidant properties of the three kinds of Hawk tea infusions were comparatively investigated. The results showed that the contents of total flavonoids, vitamin C, and carbohydrates in Hawk bud tea infusion (HBI were higher than those in Hawk primary leaf tea infusion (HPI and Hawk mature leaf tea infusion (HMI. HPI had higher contents of total polyphenols and exhibited better DPPH radical scavenging activity and ferric reducing activity power. HBI could provide more effective protection against erythrocyte hemolysis. As age is going from bud to mature leaf, the ability to inhibit the formation of low density lipoprotein (LDL conjugated diene and the loss of tryptophan fluorescence decreased. The bioactive constituents and antioxidant activities of Hawk tea infusions were significantly affected by the maturity degree of the raw material.

Hawking radiation, effective actions and covariant boundary conditions

International Nuclear Information System (INIS)

Banerjee, Rabin; Kulkarni, Shailesh

2008-01-01

From an appropriate expression for the effective action, the Hawking radiation from charged black holes is derived, using only covariant boundary conditions at the event horizon. The connection of our approach with the Unruh vacuum and the recent analysis [S.P. Robinson, F. Wilczek, Phys. Rev. Lett. 95 (2005) 011303, (gr-qc/0502074); S. Iso, H. Umetsu, F. Wilczek, Phys. Rev. Lett. 96 (2006) 151302, (hep-th/0602146); R. Banerjee, S. Kulkarni, (arXiv: 0707.2449 [hep-th])] of Hawking radiation using anomalies is established

Behavioral ecology of the Swainson's Hawk (Buteo swainsoni) in Washington

Energy Technology Data Exchange (ETDEWEB)

Fitzner, R.E.

1980-12-01

This study examines the breeding ecology and behavior of the Swainson's Hawk (Buteo swainsoni) on its breeding ground in southeastern Washington. Seasonal movements and distribution of the buteo are also described. The birds were observed from blinds, or filmed by Super-8mm time-lapse cameras, during courtship, nest building, egg laying, incubation, and nestling and post-fledging development. Food habits were examined during the nestling and post-fledging periods. Snakes, especially the abundant Western Yellow-bellied racers, were a prey staple, and insects became an important food source during the post-fledging period. It was apparent that Swainson's Hawks feed on smaller and more diverse prey than sympatric buteos (Red-tailed and Ferruginous Hawks), thus reducing competition with neighboring congenerics. Interactions with buteos and other raptor genera were observed, and nearest neighbor distances measured. Organochlorine pesticides in prey species consumed by Swainson's Hawks are concentrated from prey to predator through the food chain. The hawk pellets (regurgitated castings) would contain those concentrations and could easily be monitored without sacrificing any part of the food chain.

NASA 3D Models: Global Hawk

Data.gov (United States)

National Aeronautics and Space Administration — The ability of the Global Hawk air vehicle to autonomously fly long distances and remain aloft for extended periods of time means that measuring, monitoring, and...

75 FR 8741 - Notice of Intent to Repatriate Cultural Items: Stephen F. Austin State University, Nacogdoches, TX

Science.gov (United States)

2010-02-25

...: Stephen F. Austin State University, Nacogdoches, TX AGENCY: National Park Service, Interior. ACTION... Act (NAGPRA), 25 U.S.C. 3005, of the intent to repatriate cultural items in the control of Stephen F... of Oklahoma, which was under contract with Stephen F. Austin State University. In 1957, 15 cultural...

Local Hawking temperature for dynamical black holes

International Nuclear Information System (INIS)

Hayward, S A; Criscienzo, R Di; Nadalini, M; Vanzo, L; Zerbini, S

2009-01-01

A local Hawking temperature is derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi variant of the Parikh-Wilczek tunneling method. It is given by a dynamical surface gravity as defined geometrically. The operational meaning of the temperature is that Kodama observers just outside the horizon measure an invariantly redshifted temperature, diverging at the horizon itself. In static, asymptotically flat cases, the Hawking temperature as usually defined by the Killing vector agrees in standard cases, but generally differs by a relative redshift factor between the horizon and infinity, this being the temperature measured by static observers at infinity. Likewise, the geometrical surface gravity reduces to the Newtonian surface gravity in the Newtonian limit, while the Killing definition instead reflects measurements at infinity. This may resolve a long-standing puzzle concerning the Hawking temperature for the extremal limit of the charged stringy black hole, namely that it is the local temperature which vanishes. In general, this confirms the quasi-stationary picture of black-hole evaporation in early stages. However, the geometrical surface gravity is generally not the surface gravity of a static black hole with the same parameters. (fast track communication)

Hawkes process as a model of social interactions: a view on video dynamics

International Nuclear Information System (INIS)

Mitchell, Lawrence; Cates, Michael E

2010-01-01

We study by computer simulation the 'Hawkes process' that was proposed in a recent paper by Crane and Sornette (2008 Proc. Natl Acad. Sci. USA 105 15649) as a plausible model for the dynamics of YouTube video viewing numbers. We test the claims made there that robust identification is possible for classes of dynamic response following activity bursts. Our simulated time series for the Hawkes process indeed fall into the different categories predicted by Crane and Sornette. However, the Hawkes process gives a much narrower spread of decay exponents than the YouTube data, suggesting limits to the universality of the Hawkes-based analysis.

Hawkes process as a model of social interactions: a view on video dynamics

Energy Technology Data Exchange (ETDEWEB)

Mitchell, Lawrence; Cates, Michael E, E-mail: lawrence.mitchell@ed.ac.u [SUPA, School of Physics and Astronomy, University of Edinburgh, JCMB Kings Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom)

2010-01-29

We study by computer simulation the 'Hawkes process' that was proposed in a recent paper by Crane and Sornette (2008 Proc. Natl Acad. Sci. USA 105 15649) as a plausible model for the dynamics of YouTube video viewing numbers. We test the claims made there that robust identification is possible for classes of dynamic response following activity bursts. Our simulated time series for the Hawkes process indeed fall into the different categories predicted by Crane and Sornette. However, the Hawkes process gives a much narrower spread of decay exponents than the YouTube data, suggesting limits to the universality of the Hawkes-based analysis.

Information-carrying Hawking radiation and the number of microstate for a black hole

International Nuclear Information System (INIS)

Cai, Qing-yu; Sun, Chang-pu; You, Li

2016-01-01

We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein–Hawking entropy of extremal black holes in the semiclassical limit.

Information-carrying Hawking radiation and the number of microstate for a black hole

Energy Technology Data Exchange (ETDEWEB)

Cai, Qing-yu, E-mail: qycai@wipm.ac.cn [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Sun, Chang-pu, E-mail: cpsun@csrc.ac.cn [Beijing Computational Science Research Center, Beijing 100084 (China); Collaborative Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); You, Li, E-mail: lyou@mail.tsinghua.edu.cn [State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

2016-04-15

We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein–Hawking entropy of extremal black holes in the semiclassical limit.

Hawkes process as a model of social interactions: a view on video dynamics

Energy Technology Data Exchange (ETDEWEB)

Mitchell, Lawrence; Cates, Michael E, E-mail: lawrence.mitchell@ed.ac.u [SUPA, School of Physics and Astronomy, University of Edinburgh, JCMB Kings Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom)

2010-01-29

We study by computer simulation the 'Hawkes process' that was proposed in a recent paper by Crane and Sornette (2008 Proc. Natl Acad. Sci. USA 105 15649) as a plausible model for the dynamics of YouTube video viewing numbers. We test the claims made there that robust identification is possible for classes of dynamic response following activity bursts. Our simulated time series for the Hawkes process indeed fall into the different categories predicted by Crane and Sornette. However, the Hawkes process gives a much narrower spread of decay exponents than the YouTube data, suggesting limits to the universality of the Hawkes-based analysis.

Bogoliubov theory of the Hawking effect in Bose-Einstein condensates

International Nuclear Information System (INIS)

Leonhardt, U; Kiss, T; Oehberg, P

2003-01-01

Artificial black holes may demonstrate some of the elusive quantum properties of the event horizon, in particular Hawking radiation. One promising candidate is a sonic hole in a Bose-Einstein condensate. We clarify why Hawking radiation emerges from the condensate and how this condensed-matter analogue reflects some of the intriguing aspects of quantum black holes

Hawking temperature and scalar field fluctuations in the de-Sitter space

International Nuclear Information System (INIS)

Rozhanskij, L.V.

1988-01-01

It is shown that diffusion equation for scalar field fluctuations in the de-Sitter space corresponds to Hawking temperature. The relationship between stationary solution of the equation and Hartle-Hawking instanton at random space dimensionality and any type of gravitational effect has been established

Hawking spectrum for a fiber-optical analog of the event horizon

Science.gov (United States)

Bermudez, David; Leonhardt, Ulf

2016-05-01

Hawking radiation has been regarded as a more general phenomenon than in gravitational physics, in particular in laboratory analogs of the event horizon. Here we consider the fiber-optical analog of the event horizon, where intense light pulses in fibers establish horizons for probe light. Then, we calculate the Hawking spectrum in an experimentally realizable system. We found that the Hawking radiation is peaked around group-velocity horizons in which the speed of the pulse matches the group velocity of the probe light. The radiation nearly vanishes at the phase horizon where the speed of the pulse matches the phase velocity of light.

Kas me oleme üksi kogu universumis? Pigem siiski mitte / Krister Paris

Index Scriptorium Estoniae

Paris, Krister, 1977-

2008-01-01

See, et inimkond pole veel mujalt eluvorme leidnud, ei tähenda nende puudumist. Populaarteaduslike astronoomiateostega tuntust kogunud Stephen Hawking usub, et elu lihtsalt peab eksisteerima ka mujal maailmaruumis

Fairness and Reciprocity in the Hawk-Dove Game

DEFF Research Database (Denmark)

Poulsen, Anders; Neugebauer, Tibor; Schram, Arthur

2002-01-01

We study fairness and reciprocity in a Hawk-Dove game, using an experimental approach. This allows us to test various models in one framework. We observe a large extent of selfish and rational behavior. Our results are inconsistent with leading models in this field.......We study fairness and reciprocity in a Hawk-Dove game, using an experimental approach. This allows us to test various models in one framework. We observe a large extent of selfish and rational behavior. Our results are inconsistent with leading models in this field....

Productivity, mortality, and response to disturbance of nesting Swainson's hawks on the Hanford Site

Energy Technology Data Exchange (ETDEWEB)

Poole, L.D.; Marr, N.V.; McCorquodale, S.M.

1988-03-01

The objectives of this study were to characterize Swainson's hawk (Buteo swainson) use of the US Department of Energy (DOE) Hanford Site and to evaluate the potential for engineering and other human activities on the Hanford Site to negatively affect the nesting Swainson's hawk population. Activities associated with the Basalt Waste Isolation Project (BWIP) were used as the primary external stimuli in studying hawk responses to potential human disturbance. Parked and moving vehicles were the most common disturbance sources observed in Swainson's hawk territories. Hawks appeared to be sensitive to disturbance from pedestrians and slow-moving vehicles near nests. Novel stimuli were much more likely to evoke strong responses than were recurring events. Adult hawks reacted more frequently and vigorously than did juveniles. When disturbed, adult hawks usually flew toward the location of the disturbance; juvenile hawks usually flew away from disturbances. Human activity associated with BWIP may have had negative on one pair of nesting Swainson's hawks and may have precluded the use of an additional traditional nesting territory. Negative impacts to nesting Swainson's hawks from human activity could be minimized by confining activities to the non-nesting period or to distances greater than 2.2 km from nest sites. Tree groves and elevated perches, including utility poles, across the Hanford Site are probably critical to the success of nesting Swainson's hawks. Potential mitigation strategies associated with energy research and development activities on the Hanford Site could include provisions for maintenance and establishment of drought-tolerant trees and native vegetation. 22 refs., 5 figs., 3 tabs.

Hawking radiation of Dirac particles in the hot NUT-Kerr-Newman spacetime

International Nuclear Information System (INIS)

Ahmed, M.

1991-01-01

The Hawking radiation of charged Dirac particles on the horizons of the hot NUT-Kerr-Newman spacetime is studied in this paper. To this end, we obtain the radial decoupled Dirac equation for the electron in the hot NUT-Kerr-Newman spacetime. Next we solve the Dirac equation near the horizons. Finally, by analytic continuation, the Hawking thermal spectrum formula of Dirac particles is obtained. The problem of the Hawking evaporation of Dirac particles in the hot NUT-Kerr-Newman background is thus solved. (orig.)

Information-carrying Hawking radiation and the number of microstate for a black hole

Directory of Open Access Journals (Sweden)

Qing-yu Cai

2016-04-01

Full Text Available We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein–Hawking entropy of extremal black holes in the semiclassical limit.

Hawking radiation from quasilocal dynamical horizons

Indian Academy of Sciences (India)

2016-01-06

Jan 6, 2016 ... Abstract. In completely local settings, we establish that a dynamically evolving spherically symmetric black hole horizon can be assigned a Hawking temperature and with the emission of flux, radius of the horizon shrinks.

Hawking radiation temperatures in non-stationary Kerr black holes with different tortoise coordinate transformations

Energy Technology Data Exchange (ETDEWEB)

Lan, X.G. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); China West Normal University, Institute of Theoretical Physics, Nanchong (China); Jiang, Q.Q. [China West Normal University, Institute of Theoretical Physics, Nanchong (China); Wei, L.F. [Southwest Jiaotong University, Quantum Optoelectronics Laboratory, Chengdu (China); Sun Yat-Sen University, State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Guangzhou (China)

2012-04-15

We apply the Damour-Ruffini-Sannan method to study the Hawking radiations of scalar and Dirac particles in non-stationary Kerr black holes under different tortoise coordinate transformations. We found that all the relevant Hawking radiation spectra show still the blackbody ones, while the Hawking temperatures are strongly related to the used tortoise coordinate transformations. The properties of these dependences are discussed analytically and numerically. Our results imply that proper selections of tortoise coordinate transformations should be important in the studies of Hawking radiations and the correct selection would be given by the experimental observations in the future. (orig.)

78 FR 6321 - Stephen Phillips, Brentwood Dam Ventures, LLC; Notice of Transfer of Exemption

Science.gov (United States)

2013-01-30

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 4254-009] Stephen Phillips, Brentwood Dam Ventures, LLC; Notice of Transfer of Exemption 1. By letter filed May 31, 2006 and supplemented on January 15, 2013, Stephen Phillips and Brentwood Dam Ventures, LLC informed the Commission that...

Shepard Award Winners, Part 1: Dr. Stephen Thacker

Centers for Disease Control (CDC) Podcasts

2009-07-22

This podcast highlights the accomplishments of Dr. Stephen Thacker, recipient of the prestigious 2009 CDC Charles C. Shepard Award.  Created: 7/22/2009 by Centers for Disease Control and Prevention (CDC).   Date Released: 7/22/2009.

Hartle-Hawking wave function and large-scale power suppression of CMB*

Directory of Open Access Journals (Sweden)

Yeom Dong-han

2018-01-01

Full Text Available In this presentation, we first describe the Hartle-Hawking wave function in the Euclidean path integral approach. After we introduce perturbations to the background instanton solution, following the formalism developed by Halliwell-Hawking and Laflamme, one can obtain the scale-invariant power spectrum for small-scales. We further emphasize that the Hartle-Hawking wave function can explain the large-scale power suppression by choosing suitable potential parameters, where this will be a possible window to confirm or falsify models of quantum cosmology. Finally, we further comment on possible future applications, e.g., Euclidean wormholes, which can result in distinct signatures to the power spectrum.

Hawk-Eyes on Science and in Space

Science.gov (United States)

Durow, Lillie

2017-08-01

For more than ten years the successful and well received outreach programs, Hawk-Eyes On Science and Hawk-Eyes in Space, have brought the excitement of science demonstrations to Iowans of all ages. However, the creation of a successful, sustainable outreach program requires the coordination of many aspects. In many respects, the demonstrations and hands-on activities are of secondary importance when weighed against the problems of funding, transportation, staffing, etc. In addition to showing examples of demonstrations that we use, I will also focus on a few of the problems and some of the solutions that we have found while coordinating our long running outreach programs at the University of Iowa Department of Physics and Astronomy.

From the big bang to the eureka moment

Energy Technology Data Exchange (ETDEWEB)

Rodgers, Peter

2002-02-01

A Brief History of Time made Stephen Hawking famous, but he was already a world leader in cosmology. Peter Rodgers reports from the celebrations to mark Hawking's 60th birthday. Masters of the universe Stephen Hawking is the most famous physicist in the world. Indeed, the sales of Hawking's books and his appearances on The Simpsons and Star Trek have tended to overshadow his scientific achievements. But that was not the case in Cambridge last month when Hawking's contributions to physics and cosmology were celebrated at a week-long conference to mark his 60th birthday. 'We organized the meeting to look back on the immense contribution that Stephen has made to many areas of gravitational physics and cosmology,' said Gary Gibbons, one of Hawking's colleagues at Cambridge. 'We also wanted to look forward to what the future might hold for theoretical physics and cosmology, with special reference to the areas that Stephen has been most interested and most active in.' Hawking made his name with a series of papers in the 1960s on singularities in cosmology. Building on work by Roger Penrose, he showed that Einstein's general theory of relativity implied that space and time would have a beginning in the big bang and would end in a singularity. 'How unlike particle physics, where people were falling over themselves to latch onto the latest idea. They still are.' Hawking then switched his attention to black holes - regions of space where gravity is so strong that nothing can escape. He was also one of the first physicists to make progress in combining general relativity - the classical theory of gravity - and quantum mechanics. First he showed that when two black holes collide and merge, the area of the 'event horizon' around the resulting black hole is greater than the sum of the two original areas. This led Hawking and co-workers to link the area of the event horizon, A, with the entropy of a black hole, S

Stephen H. Schneider (1945-2010)

Science.gov (United States)

Santer, Ben; Solomon, Susan

2010-10-01

Stephen H. Schneider, a pioneering climate scientist, prolific author, and inspirational teacher, passed away on 19 July 2010 while on travel in Europe. He was 65. As is clear from the outpouring of testimonials since his passing, atmospheric science has lost a towering figure, one whose impact as a scientist and communicator was exceeded only by his extraordinary human qualities. Steve Schneider touched lives; built bridges of communication to the public, to policy makers, and across disciplines; and established a distinguished record of seminal scientific breakthroughs.

Street Hawking: Oppressing the Girl Child or Family Economic Supplement?

Science.gov (United States)

Umar, Fatima M.

2009-01-01

Street hawking in its simplest form is the selling of things along the roads and from one place to the other. In Nigeria this is done almost all the time by young children both males and females. The girl hawkers come to the cities in groups and then go in different directions of the city to hawk their goods. They remain in the city from the early…

Red-shouldered hawk nesting habitat preference in south Texas

Science.gov (United States)

Strobel, Bradley N.; Boal, Clint W.

2010-01-01

We examined nesting habitat preference by red-shouldered hawks Buteo lineatus using conditional logistic regression on characteristics measured at 27 occupied nest sites and 68 unused sites in 2005–2009 in south Texas. We measured vegetation characteristics of individual trees (nest trees and unused trees) and corresponding 0.04-ha plots. We evaluated the importance of tree and plot characteristics to nesting habitat selection by comparing a priori tree-specific and plot-specific models using Akaike's information criterion. Models with only plot variables carried 14% more weight than models with only center tree variables. The model-averaged odds ratios indicated red-shouldered hawks selected to nest in taller trees and in areas with higher average diameter at breast height than randomly available within the forest stand. Relative to randomly selected areas, each 1-m increase in nest tree height and 1-cm increase in the plot average diameter at breast height increased the probability of selection by 85% and 10%, respectively. Our results indicate that red-shouldered hawks select nesting habitat based on vegetation characteristics of individual trees as well as the 0.04-ha area surrounding the tree. Our results indicate forest management practices resulting in tall forest stands with large average diameter at breast height would benefit red-shouldered hawks in south Texas.

On the stringy Hartle-Hawking state

Science.gov (United States)

Ben-Israel, Roy; Giveon, Amit; Itzhaki, Nissan; Liram, Lior

2016-03-01

We argue that non-perturbative α' stringy effects render the Hartle-Hawking state associated with the SL(2)/U(1) eternal black hole singular at the horizon. We discuss implications of this observation on firewalls in string theory.

Habitat segregation in two congeric hawk-eagles (Spizaetus bartelsi abd S. cirrhatus) in Java, Indonesia

NARCIS (Netherlands)

Nijman, V.

2004-01-01

On the island of Java, Indonesia, two congeneric hawk-eagles occur, i.e. the endemic Javan hawk-eagle Spizaetus bartelsi and the wide-ranging changeable hawk-eagle S. cirrhatus. Comparisons with similar species-pairs in South East Asia suggest that these species may be competitors both in habitat

MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON’S HAWKS

Science.gov (United States)

Kochert, Michael N.; Fuller, Mark R.; Schueck, Linda S.; Bond, Laura; Bechard, Marc J.; Woodbridge, Brian; Holroyd, Geoff; Martell, Mark; Banasch, Ursula

2015-01-01

From 1995–1998, we tracked movements of adult Swainson’s Hawks (Buteo swainsoni) using satellite telemetry to characterize migration, important stopover areas, and austral summer movements. We tagged 46 hawks from July - September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson’s Hawks basically followed three routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal austral summer area in central Argentina. North of 20° N, southward and northward tracks differed little for individuals from east of the Continental Divide but differed greatly (up to 1700 km) for individuals from west of the Continental Divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. South migration lasted 42 to 98 days, and north migration took 51 to 82 days. On south migration, 36% of the Swainson’s Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio marked hawks and made stopovers 9.0 – 26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and north-central Mexico. The austral period lasted 76 to 128 days. All Swainson’s Hawks used a core area in central Argentina within 23% of the 738800 km2 austral summer range where they frequently moved long distances (up to 1600 km). Conservation of Swainson’s Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons including migration stopovers. PMID:26380528

On the stringy Hartle-Hawking state

International Nuclear Information System (INIS)

Ben-Israel, Roy; Giveon, Amit; Itzhaki, Nissan; Liram, Lior

2016-01-01

We argue that non-perturbative α"′ stringy effects render the Hartle-Hawking state associated with the SL(2)/U(1) eternal black hole singular at the horizon. We discuss implications of this observation on firewalls in string theory.

Critical reflexivity in financial markets: a Hawkes process analysis

Science.gov (United States)

Hardiman, Stephen J.; Bercot, Nicolas; Bouchaud, Jean-Philippe

2013-10-01

We model the arrival of mid-price changes in the E-mini S&P futures contract as a self-exciting Hawkes process. Using several estimation methods, we find that the Hawkes kernel is power-law with a decay exponent close to -1.15 at short times, less than ≈ 103 s, and crosses over to a second power-law regime with a larger decay exponent ≈-1.45 for longer times scales in the range [ 103,106 ] seconds. More importantly, we find that the Hawkes kernel integrates to unity independently of the analysed period, from 1998 to 2011. This suggests that markets are and have always been close to criticality, challenging a recent study which indicates that reflexivity (endogeneity) has increased in recent years as a result of increased automation of trading. However, we note that the scale over which market events are correlated has decreased steadily over time with the emergence of higher frequency trading.

On the stringy Hartle-Hawking state

Energy Technology Data Exchange (ETDEWEB)

Ben-Israel, Roy [Physics Department, Tel-Aviv University,Ramat-Aviv, 69978 (Israel); Giveon, Amit [Racah Institute of Physics, The Hebrew University,Jerusalem, 91904 (Israel); Itzhaki, Nissan; Liram, Lior [Physics Department, Tel-Aviv University,Ramat-Aviv, 69978 (Israel)

2016-03-03

We argue that non-perturbative α{sup ′} stringy effects render the Hartle-Hawking state associated with the SL(2)/U(1) eternal black hole singular at the horizon. We discuss implications of this observation on firewalls in string theory.

Astronaut Stephen Oswald during emergency bailout training

Science.gov (United States)

1994-01-01

Suited in a training version of the Shuttle partial-pressure launch and entry garment, astronaut Stephen S. Oswald, STS-67 commander, gets help with a piece of gear from Boeing's David Brandt. The scene was photographed prior to a session of emergency bailout training in the 25-feet deep pool at JSC's Weightless Environment Training Facility (WETF).

Beyond the black hole

International Nuclear Information System (INIS)

Boslough, J.

1985-01-01

This book is about the life and work of Stephen Hawking. It traces the development of his theories about the universe and particularly black holes, in a biographical context. Hawking's lecture 'Is the end in sight for theoretical physics' is presented as an appendix. In this, he discusses the possibility of achieving a complete, consistent and unified theory of the physical interactions which would describe all possible observations. (U.K.)

Quantum Signature of Analog Hawking Radiation in Momentum Space.

Science.gov (United States)

Boiron, D; Fabbri, A; Larré, P-É; Pavloff, N; Westbrook, C I; Ziń, P

2015-07-10

We consider a sonic analog of a black hole realized in the one-dimensional flow of a Bose-Einstein condensate. Our theoretical analysis demonstrates that one- and two-body momentum distributions accessible by present-day experimental techniques provide clear direct evidence (i) of the occurrence of a sonic horizon, (ii) of the associated acoustic Hawking radiation, and (iii) of the quantum nature of the Hawking process. The signature of the quantum behavior persists even at temperatures larger than the chemical potential.

Toward Valid Measurement of Stephen Pepper's World Hypotheses.

Science.gov (United States)

Johnson, John A.

Two measures of the "world hypotheses" of Stephen Pepper were mailed to 100 sociobiologists, 87 behaviorists, 79 personality psychologists, and 45 human developmentalists. The World Hypothesis Scale (WHS) was designed to measure Pepper's four world views: (1) formism; (2) mechanism; (3) organicism; and (4) contextualism. The…

Conformal nature of the Hawking radiation

International Nuclear Information System (INIS)

Materassi, M.

2000-01-01

String theory usually represents quantum black holes as systems whose statistical mechanics reproduces Hawking's thermodynamics in a very satisfactory way. Complicated brane theoretical models are worked out, as quantum versions of Supergravity solutions. These models are then assumed to be in thermal equilibrium: this is a little cheating, because one is looking for an explanation of the seeming thermodynamical nature of black holes, so they cannot be assumed to be finite temperature systems! In the model presented here, the black body spectrum arises with no statistical hypothesis as an approximation of the unitary evolution of microscopic black holes, which are always described by a 1+1 conformal field theory, characterized by some Virasoro algebra. At the end, one can state that the Hawking-thermodynamics of the system is a by-product of the algebraic Virasoro-symmetric nature of the event horizon. This is the central result of the present work. (author)

Hawking radiation and tunneling mechanism for a new class of black holes in Einstein-Gauss-Bonnet gravity

International Nuclear Information System (INIS)

Muneyuki, Kenji; Ohta, Nobuyoshi

2012-01-01

We study Hawking radiation in a new class of black hole solutions in Einstein-Gauss-Bonnet theory. The black hole has been argued to have vanishing mass and entropy, but finite Hawking temperature. To check if it really emits radiation, we analyze Hawking radiation using the original method of quantization of a scalar field in the black hole background and with the quantum tunneling method, and confirm that it emits radiation at the Hawking temperature. A general formula is derived for the Hawking temperature and backreaction in the tunneling approach. Physical implications of these results are discussed. (orig.)

78 FR 49469 - Stephen Glen Guerra, Inmate #98595-279, FCI Yazoo City Medium, Federal Correctional Institution...

Science.gov (United States)

2013-08-14

... DEPARTMENT OF COMMERCE Bureau of Industry and Security Stephen Glen Guerra, Inmate 98595-279, FCI... Export Privileges On February 6, 2012, in the U.S. District Court, Western District of Texas, Stephen... conviction. [[Page 49470

The Hawking evaporation process of rapidly-rotating black holes: an almost continuous cascade of gravitons

International Nuclear Information System (INIS)

Hod, Shahar

2015-01-01

It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ gap /τ emission = O(1), where τ gap is the average time gap between the emissions of successive Hawking quanta and τ emission is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)

The Hawking evaporation process of rapidly-rotating black holes: an almost continuous cascade of gravitons

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emek Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)

2015-07-15

It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ{sub gap}/τ{sub emission} = O(1), where τ{sub gap} is the average time gap between the emissions of successive Hawking quanta and τ{sub emission} is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)

Approximate simulation of Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Rasmussen, Jakob Gulddahl

This article concerns a simulation algorithm for unmarked and marked Hawkes processes. The algorithm suffers from edge effects but is much faster than the perfect simulation algorithm introduced in our previous work. We derive various useful measures for the error committed when using the algorithm......, and we discuss various empirical results for the algorithm compared with perfect simulations....

Cyanide poisoning of a Cooper’s hawk (Accipiter cooperii)

Science.gov (United States)

Franson, J. Christian

2017-01-01

A Cooper’s hawk (Accipiter cooperii) was found dead in a ditch leading from a heap leach pad at a gold mine in Nevada. Observations at autopsy included an absence of external lesions, traces of subcutaneous and coronary fat, no food in the upper gastrointestinal tract, and no lesions in the viscera. Cyanide concentrations (µg/g ww) were 5.04 in blood, 3.88 in liver, and 1.79 in brain. No bacteria or viruses were isolated from tissues, and brain cholinesterase activity was within the normal range for a Cooper’s hawk.

My brief history. 2. ed.; Meine kurze Geschichte

Energy Technology Data Exchange (ETDEWEB)

Hawking, Stephen

2015-11-01

For the first time, Stephen Hawking turns his gaze inward for a revealing look at his own life and intellectual evolution. My Brief History recounts Stephen Hawking's improbable journey, from his post-war London boyhood to his years of international acclaim and celebrity. Illustrated with rarely seen photographs, this concise, witty and candid account introduces readers to the inquisitive schoolboy whose classmates nicknamed him 'Einstein'; the jokester who once placed a bet with a colleague over the existence of a black hole; and the young husband and father striving to gain a foothold in the world of academia. Writing with humility and humour, Hawking opens up about the challenges that confronted him following his diagnosis of ALS aged twenty-one. Tracing his development as a thinker, he explains how the prospect of an early death urged him onward through numerous intellectual breakthroughs, and talks about the genesis of his masterpiece A Brief History of Time - one of the iconic books of the twentieth century.

My brief history. 2. ed.

International Nuclear Information System (INIS)

Hawking, Stephen

2015-01-01

For the first time, Stephen Hawking turns his gaze inward for a revealing look at his own life and intellectual evolution. My Brief History recounts Stephen Hawking's improbable journey, from his post-war London boyhood to his years of international acclaim and celebrity. Illustrated with rarely seen photographs, this concise, witty and candid account introduces readers to the inquisitive schoolboy whose classmates nicknamed him 'Einstein'; the jokester who once placed a bet with a colleague over the existence of a black hole; and the young husband and father striving to gain a foothold in the world of academia. Writing with humility and humour, Hawking opens up about the challenges that confronted him following his diagnosis of ALS aged twenty-one. Tracing his development as a thinker, he explains how the prospect of an early death urged him onward through numerous intellectual breakthroughs, and talks about the genesis of his masterpiece A Brief History of Time - one of the iconic books of the twentieth century.

Hawking radiation and quantum anomaly in AdS2/CFT1 correspondence

International Nuclear Information System (INIS)

Morita, Takeshi

2009-01-01

In order to understand a boundary description of Hawking radiation in the AdS/CFT correspondence, we investigate the trace anomaly method in AdS 2 space. In this method, Hawking radiation is derived from the trace anomaly of the energy-momentum tensor in the bulk. We find a correspondence between the energy-momentum tensor and a composite operator in CFT 1 and understand the anomalous properties of the energy-momentum tensor in terms of this composite operator. By using this correspondence, we reproduce Hawking radiation from the boundary description. In addition, we find a correspondence between higher-spin currents in the bulk and composite operators in the boundary.

Refresher Course in Theoretical Physics at St. Stephen's College ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 5. Refresher Course in Theoretical Physics at St. Stephen's College University of Delhi, Delhi. Information and Announcements Volume 7 Issue 5 May 2002 pp 103-103 ...

Back reaction, the Hawking emission spectrum from the charged black hole

International Nuclear Information System (INIS)

Xu Pingchuan; Wang Zhihong; Han Yan

2011-01-01

The Hawking emission spectrum of the Schwarzschild-like black hole has been successfully described in the tunneling picture. In this paper, we develop the idea for the case of the charged black hole with back reaction. First, the most general, static spherically symmetric charged black hole, in the presence of back reaction, has been provided by solving the Einstein equations with a non-zero vacuum expectation value of the energy-momentum tensor (T μν (φ, g μν )). At the one-loop corrections, we also produce the modified expressions for the Hawking temperature and Bekenstein-Hawking entropy. It is found that the leading correction to the semiclassical entropy is logarithmic and next to the leading order is inverse of the horizon area, just as the expected well-known results. In particular, as our main focus in this paper, we show that the modified black hole still radiates with a perfect blackbody spectrum, only the temperature undergoing quantum corrections. Also, the Hawking fluxes of the electric current and energy-momentum tensor to include the effect of back reaction are obtained. The results are interestingly found sharing the same form as that from the point of anomaly.

Hawking radiation, entanglement, and teleportation in the background of an asymptotically flat static black hole

International Nuclear Information System (INIS)

Pan Qiyuan; Jing Jiliang

2008-01-01

The effect of the Hawking temperature on the entanglement and teleportation for the scalar field in a most general, static, and asymptotically flat black hole with spherical symmetry has been investigated. It has been shown that the same 'initial entanglement' for the state parameter α and its 'normalized partners'√(1-α 2 ) will be degraded by the Hawking effect with increasing Hawking temperature along two different trajectories except for the maximally entangled state. In the infinite Hawking temperature limit, corresponding to the case of the black hole evaporating completely, the state no longer has distillable entanglement for any α. It is interesting to note that the mutual information in this limit is equal to just half of the 'initially mutual information'. It has also been demonstrated that the fidelity of teleportation decreases as the Hawking temperature increases, which indicates the degradation of entanglement.

Numerical observation of Hawking radiation from acoustic black holes in atomic Bose-Einstein condensates

International Nuclear Information System (INIS)

Carusotto, Iacopo; Recati, Alessio; Fagnocchi, Serena; Balbinot, Roberto; Fabbri, Alessandro

2008-01-01

We report numerical evidence of Hawking emission of Bogoliubov phonons from a sonic horizon in a flowing one-dimensional atomic Bose-Einstein condensate. The presence of Hawking radiation is revealed from peculiar long-range patterns in the density-density correlation function of the gas. Quantitative agreement between our fully microscopic calculations and the prediction of analog models is obtained in the hydrodynamic limit. New features are predicted and the robustness of the Hawking signal against a finite temperature discussed.

Total spectral distributions from Hawking radiation

Energy Technology Data Exchange (ETDEWEB)

Broda, Boguslaw [University of Lodz, Department of Theoretical Physics, Faculty of Physics and Applied Informatics, Lodz (Poland)

2017-11-15

Taking into account the time dependence of the Hawking temperature and finite evaporation time of the black hole, the total spectral distributions of the radiant energy and of the number of particles have been explicitly calculated and compared to their temporary (initial) blackbody counterparts (spectral exitances). (orig.)

Black hole state evolution, final state and Hawking radiation

International Nuclear Information System (INIS)

Ahn, D

2012-01-01

The effect of a black hole state evolution on the Hawking radiation is studied using the final state boundary condition. It is found that the thermodynamic or statistical mechanical properties of a black hole depend strongly on the unitary evolution operator S, which determines the black hole state evolution. When the operator S is random unitary or pseudo-random unitary, a black hole emits thermal radiation as predicted by Hawking three decades ago. In particular, when the black hole mass of the final state vanishes, Hawking’s original result is retrieved. On the other hand, it is found that the emission of the Hawking radiation could be suppressed when the evolution of a black hole state is determined by the generator of the coherent state. Such a case can occur for some primordial black holes with Planck scale mass formed by primordial density fluctuations through the process of squeezing the zero-point quantum fluctuation of a scalar field. Those primordial black holes can survive until the present time and can contribute to cold dark matter. (paper)

Ecology of a nesting red-shouldered hawk population

Science.gov (United States)

Stewart, R.E.

1949-01-01

An ecological study of a nesting Red-shouldered Hawk population was made over a 185 square mile area on the Coastal Plain of Maryland in 1947. The courting and nesting season extended from late February until late June.....During the nesting season a combination of fairly extensive flood-plain forest with adjacent clearings appears to meet the major ecological requirements of the Red-shouldered Hawk in this region. A total of 51 pairs was found in the study area, occupying about 42 square miles or 23% of the total area studied. The population density on the land that was suitable for this species was about 1 pair per .8 of a square mile, while the density for the entire study area would be only about 1 pair per 3.6 square miles.....Nests were spaced fairly evenly over most of the flood-plain forests, especially in areas where the width.of the flood plain was relatively constant. There was an inverse correlation between the width of the flood plain and the distances between nests in adjacent territories. The nests were all situated in fairly large trees and were from 28 feet to 77 feet above the ground, averaging 50. They were found in 14 different species of trees, all deciduous.....The Barred Owl and Red-shouldered Hawk were commonly associated together in the same lowland habitats. Other raptores were all largely restricted to upland habitats....The average number of young in 47 occupied nests following the hatching period was 2.7 with extremes of 1 and 4. Only 3 out of 52 nests (6%) were found deserted at this time....The food habits of nestling Red-shouldered Hawks are very diversified. They feed on many types of warm-blooded and cold-blooded vertebrates as well as invertebrates.

Aiakunstnik Stephen Woodhamsi avara väljavaatega korter / Jo Denbury

Index Scriptorium Estoniae

Denbury, Jo

2007-01-01

2002. aastal Chelsea aianäitusel kuldmedali võitnud aiadisainer Stephen Woodhamsi rütmiliste kordustega saavutatud avar talveaiaga kodu, kus kasutatud neoonroosat ja kahvatulillat valgustust. Lk. 32 intervjuu kunstnikuga

Hawk-I - First results from science verification

NARCIS (Netherlands)

Kissler-Patig, M.; Larsen, S.S.|info:eu-repo/dai/nl/304833347; Wehner, E.M.|info:eu-repo/dai/nl/314114688

2008-01-01

The VLT wide-field near-infrared imager HAWK-I was commissioned in 2007 and Science Verification (SV) programmes were conducted in August 2007. A selection of results from among the twelve Science Verfication proposals are summarised.

The Hawkes process with different excitation functions and its asymptotoc behavior

DEFF Research Database (Denmark)

Fierro, Raúl; Leiva, Víctor; Møller, Jesper

The standard Hawkes process is constructed from a homogeneous Poisson process and using the same exciting function for dierent generations of offspring. We propose an extension of this process by considering different exciting functions. This consideration could be important to be taken into acco......The standard Hawkes process is constructed from a homogeneous Poisson process and using the same exciting function for dierent generations of offspring. We propose an extension of this process by considering different exciting functions. This consideration could be important to be taken...... into account in a number of fields; e.g. in seismology, where main shocks produce aftershocks with possibly different intensities. The main results are devoted to the asymptotic behavior of this extension of the Hawkes process. Indeed, a law of large numbers and a central limit theorem are stated...

Why the matter of matter should matter to more than two eminent scientists

CERN Multimedia

Linklater, M

2002-01-01

Stephen Hawking has bet $100 that the Higgs boson will not be discovered. As a result, he has been heavily criticized by Peter Higgs, who first hypothesized the particles existence in the 1960s (1 page).

South African Journal of Philosophy - Vol 31, No 2 (2012)

African Journals Online (AJOL)

The death of Philosophy: A response to Stephen Hawking · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. CD Scott, 385-404. http://dx.doi.org/10.1080/02580136.2012.10751783 ...

Hawking temperatures of Myers-Perry black holes from tunneling

International Nuclear Information System (INIS)

Ma Zhengze

2009-01-01

Using the tunneling method of Parikh and Wilczek, we derive the Hawking temperature of a general higher-dimensional rotating black hole which is equal to its surface gravity on the horizon divided by 2π. In order to eliminate the motion on the rotating degrees of freedom of a tunneling particle from a higher-dimensional rotating black hole, we choose a reference system that is co-rotating with the black hole horizon. Then, we apply the obtained result to the Myers-Perry higher-dimensional asymptotically flat black holes and reproduce their Hawking temperatures using the tunneling approach.

Hawking radiation of a high-dimensional rotating black hole

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ren; Zhang, Lichun; Li, Huaifan; Wu, Yueqin [Shanxi Datong University, Institute of Theoretical Physics, Department of Physics, Datong (China)

2010-01-15

We extend the classical Damour-Ruffini method and discuss Hawking radiation spectrum of high-dimensional rotating black hole using Tortoise coordinate transformation defined by taking the reaction of the radiation to the spacetime into consideration. Under the condition that the energy and angular momentum are conservative, taking self-gravitation action into account, we derive Hawking radiation spectrums which satisfy unitary principle in quantum mechanics. It is shown that the process that the black hole radiates particles with energy {omega} is a continuous tunneling process. We provide a theoretical basis for further studying the physical mechanism of black-hole radiation. (orig.)

Anomalies and Hawking radiation from the Reissner-Nordstroem black hole with a global monopole

International Nuclear Information System (INIS)

Wu Shuangqing; Peng Junjin

2007-01-01

We extend the work by Iso, Umetsu and Wilczek (2006 Phys. Rev. Lett. 96 151302) to derive the Hawking flux via gauge and gravitational anomalies of a most general two-dimensional non-extremal black hole spacetime with the determinant of its diagonal metric differing from unity √ (-g)1) ≠ 1 and use it to investigate Hawking radiation from the Reissner-Nordstroem black hole with a global monopole by requiring the cancellation of anomalies at the horizon. It is shown that the compensating energy-momentum and gauge fluxes required to cancel gravitational and gauge anomalies at the horizon are precisely equivalent to the (1 + 1)-dimensional thermal fluxes associated with Hawking radiation emanating from the horizon at the Hawking temperature. These fluxes are universally determined by the value of anomalies at the horizon

The Hawking cascade from a black hole is extremely sparse

International Nuclear Information System (INIS)

Gray, Finnian; Schuster, Sebastian; Van–Brunt, Alexander; Visser, Matt

2016-01-01

The average time between emission of subsequent quanta in the Hawking process is extremely large. While this sparsity result has been known for a long time, it is neither well-known, nor do (semi-)analytic results currently exist, the prior focus being placed on numerical results. We define several ways of quantifying this sparsity, and starting from a black body approximation for the Schwarzschild case, we derive analytic expressions for a lower bound on this average time. We also check the validity of the results in presence of greybody factors by numerical analysis. Furthermore, we show how to separate the super-radiance in the low-frequency regime from the genuine Hawking effect itself. This enables us to extend the previous lower bounds to Reissner–Nordström, Kerr and dirty black holes in addition to different particle species. Lastly, we want to draw attention to some of the physical consequences of this under-appreciated fact of the Hawking process. (paper)

2015-2016 Travel and Hospitality Expense Reports for Stephen ...

International Development Research Centre (IDRC) Digital Library (Canada)

Ruxandra Staicu

Description. Working lunch to discuss IDRC programming and the CGIAR. Date. 2015-11-12. Attendees. 2 (IDRC 1, Guest 1). Location. Ottawa. Total. $55.05. Comments. 2015-2016 Travel and Hospitality Expense. Reports for Stephen McGurk, Vice-President,. Program and Partnership Branch.

Quantifying Trade-Offs Among Ecosystem Services, Biodiversity, and Agricultural Returns in an Agriculturally Dominated Landscape Under Future Land‑Management Scenarios

Directory of Open Access Journals (Sweden)

Emma C. Underwood

2017-07-01

Full Text Available https://doi.org/10.15447/sfews.2017v15iss2art4Change in land use in agriculturally dominated areas is often assumed to provide positive benefits for land-owners and financial agricultural returns at the expense of biodiversity and other ecosystem services. For an agriculturally dominated area in the Central Valley of California we quantify the trade-offs among ecosystem services, biodiversity, and the financial returns from agricultural lands. We do this by evaluating three different landscape management scenarios projected to 2050 compared to the current baseline: habitat restoration, urbanization, and enhanced agriculture. The restoration scenario benefited carbon storage services and increased landscape suitability for birds, and also decreased ecosystem disservices (nitrous oxide emissions, nitrogen leaching, although there was a trade-off in slightly lower financial agricultural returns. Under the urbanization scenario, carbon storage, suitability for birds, and agricultural returns were negatively affected. A scenario which enhanced agriculture, tailored to the needs of a key species of conservation concern (Swainson’s Hawk, Buteo swainsoni, presented the most potential for trade-offs. This scenario benefitted carbon storage and increased landscape suitability for the Swainson's Hawk as well as 15 other focal bird species. However, this scenario increased ecosystem disservices. These spatially explicit results, generated at a scale relevant to land management decision-makers in the Central Valley, provide valuable insight into managing for multiple benefits in the landscape and an approach for assessing future land-management decisions.

Autumn raptor banding at hawk Ridge, Duluth, Minnesota USA, 1972-2009: An overview

Science.gov (United States)

This manuscript is targeted to a specialized audience: ornithologists who work specifically on raptors (hawks and owls). The goal of the paper is to describe the last 38 years of banding at Hawk Ridge Bird Observatory and to put out some preliminary results on species’ annual dy...

Paul Dirac

Science.gov (United States)

Pais, Abraham; Jacob, Maurice; Olive, David I.; Atiyah, Michael F.

2005-09-01

Preface Peter Goddard; Dirac memorial address Stephen Hawking; 1. Paul Dirac: aspects of his life and work Abraham Pais; 2. Antimatter Maurice Jacob; 3. The monopole David Olive; 4. The Dirac equation and geometry Michael F. Atiyah.

"Universe" event at AIMS

Science.gov (United States)

2008-06-01

Report of event of 11 May 2008 held at the African Institute of Mathematical Sciences (Muizenberg, Cape), with speakers Michael Griffin (Administrator of NASA), Stephen Hawking (Cambridge), David Gross (Kavli Institute, Santa Barbara) and George Smoot (Berkeley).

Aspects of quantum field theory in curved space-time

CERN Document Server

Fulling, Stephen A

1989-01-01

The theory of quantum fields on curved spacetimes has attracted great attention since the discovery, by Stephen Hawking, of black-hole evaporation. It remains an important subject for the understanding of such contemporary topics as inflationary cosmology

Hawking radiation from astrophysical black holes to analogous systems in lab

CERN Document Server

Belgiorno, Francesco D

2018-01-01

The aim of this book is to provide the reader with a guide to Hawking radiation through a dual approach to the problem. In the first part of the book, we summarize some basic knowledge about black holes and quantum field theory in curved spacetime. In the second part, we present a survey of methods for deriving and studying Hawking radiation from astrophysical black holes, from the original calculation by S W Hawking to the most recent contributions involving gravitational anomalies and tunneling. In the third part, we introduce analogue gravity models, with particular attention to dielectric black hole systems, to which the studies of the present authors are devoted. The mutual interchange of knowledge between the aforementioned parts is addressed to render a more comprehensive picture of this very fascinating quantum phenomenon associated with black holes.

Street hawking among in-school adolescents in a south-western town in Nigeria: pattern, determinants and effects on school performance.

Science.gov (United States)

Ijadunola, Macellina Y; Ojo, Temitope O; Babatunde, Adelekan; Olatunji, Gbajumo J; Owolabi, Gbolagade K; Adewale, Ibiyemi A; Ifedayo, Ibukun F; Friday, Ijuewe S

2015-02-01

Street hawking is the commonest form of child labor in Nigeria. Although street hawking is very pervasive, there is the increasing need to fully understand its pattern and effects on those involved in hawking particularly adolescents who combine schooling with hawking. In Nigeria, data on the effects of street hawking on in-school adolescents are generally scanty. Therefore, the present study was undertaken in Ife Central Local Government Area (LGA) of Osun State, Nigeria to assess the pattern, determinants of street hawking among in-school adolescents and its effect on school performance. A cross-sectional study of 435 adolescents (aged 10-19) attending public secondary schools was done. Data were collected using facilitated self-administered questionnaires alongside a review of class records. Appropriate statistical analysis including multiple regression was done. Results showed mean age of respondents to be 14.6±2.1 years with prevalence of street hawking at 37.2%. Early adolescents (10-13 years) were more likely to engage in street hawking compared to their counterparts in late adolescence (aged 17-19). Female adolescents and students of trading mothers were significantly more likely to engage in street hawking. Respondents engaged in street hawking were significantly more likely to have failed the last academic term examination. The findings from this study will be useful for stakeholders as they develop policies and programmes to address the challenge of street hawking among adolescent school goers.

Researching on Hawking Effect in a Kerr Space Time via Open Quantum System Approach

International Nuclear Information System (INIS)

Liu, Wen-Biao; Liu, Xian-Ming

2014-01-01

It has been proposed that Hawking radiation from a Schwarzschild or a de Sitter spacetime can be understood as the manifestation of thermalization phenomena in the framework of an open quantum system. Through examining the time evolution of a detector interacting with vacuum massless scalar fields, it is found that the detector would spontaneously excite with a probability the same as the thermal radiation at Hawking temperature. Following the proposals, the Hawking effect in a Kerr space time is investigated in the framework of an open quantum systems. It is shown that Hawking effect of the Kerr space time can also be understood as the the manifestation of thermalization phenomena via open quantum system approach. Furthermore, it is found that near horizon local conformal symmetry plays the key role in the quantum effect of the Kerr space time

Buteo Nesting Ecology: Evaluating Nesting of Swainson's Hawks in the Northern Great Plains.

Science.gov (United States)

Inselman, Will M; Datta, Shubham; Jenks, Jonathan A; Jensen, Kent C; Grovenburg, Troy W

2015-01-01

Swainson's hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson's hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson's hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, SDist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%-42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson's hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson's hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson's hawks arriving to the breeding grounds.

Stephen Kingi tee tumeda tornini võttis 30 aastat / Raul Sulbi

Index Scriptorium Estoniae

Sulbi, Raul

2007-01-01

Stephen Kingi triloogiast "Tume torn" (Tallinn : Pegasus, 2006-2007) : Laskur : [romaan] / tõlkija Mart Kalvet ; Kolm saatusekaarti / [tõlkinud Kaido Haavandi] ; Ahermaad / [tõlkinud Matti Piirimaa] ;

2017-2018 Hospitality Expense Reports for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

SD

Description: Lunch - Development research issues. Date: 2017-05-30. Attendees: 2 (IDRC 1). Location: Nairobi, Kenya. Total: $12.10. Comments: 2017-2018 Hospitality Expense Reports for. Stephen McGurk, Vice-President, Program and Partnership Branch.

2016-2017 Hospitality Expense Reports for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Beata Bialic

Description: Lunch to discuss IDRC programming. Date: 2016-10-04. Attendees: 2 (IDRC 1). Location: Ottawa. Total: $25.99. Comments: 2016-2017 Hospitality Expense Reports for. Stephen McGurk, Vice-President, Programs and Partnership Branch.

Hawking radiation from black holes in de Sitter spaces

International Nuclear Information System (INIS)

Jiang Qingquan

2007-01-01

Recently, Hawking radiation has been treated, by Robinson and Wilczek (2005 Phys. Rev. Lett. 95 011303), as a compensating flux of the energy-momentum tensor required to cancel a gravitational anomaly at the event horizon (EH) of a Schwarzschild-type black hole. In this paper, motivated by this work, Hawking radiation from the event horizon (EH) and the de Sitter cosmological horizon (CH) of black holes in de Sitter spaces, specifically including the purely de Sitter black hole and the static, spherically symmetric Schwarzschild-de Sitter black hole as well as the rotating Kerr-de Sitter black hole, have been studied by anomalies. The results show that the gauge-current and energy-momentum tensor fluxes, required to restore gauge invariance and general coordinate covariance at the EH and the CH, are precisely equal to those of Hawking radiation from the EH and the CH, respectively. It should be noted that gauge and gravitational anomalies taking place at the CH arise from the fact that the effective field theory is formulated inside the CH to integrate out the classically irrelevant outgoing modes at the CH, which are different from those at the black hole horizon

Multiyear Procurement (MYP) and Block Buy Contracting in Defense Acquisition: Background and Issues for Congress

Science.gov (United States)

2017-03-16

approaches, see CRS Report RL31404, Defense Procurement: Full Funding Policy— Background, Issues, and Options for Congress, by Ronald O’Rourke and Stephen ...proposing  a multiyear procurement contract for FY2017-FY2021 for procuring UH-60M Black Hawk helicopters; and  a multiyear contract for FY2017-FY2021...as reported states: SEC. 112. Multiyear procurement authority for UH–60M and HH–60M Black Hawk helicopters. (a) Authority for multiyear procurement

The Singularity, or How I Learned to Stop Worrying and Love AI

OpenAIRE

Bishop, Mark (J. M.)

2015-01-01

Professor Stephen Hawking recently warned about the growing power of Artificial Intelligence (AI) to imbue robots with the ability to both replicate them- selves and to increase the rate at which they get smarter - leading to a tipping point or ‘technological singularity’ when they can outsmart humans. In this chapter I will argue that Hawking is essentially correct to flag up an existential danger surrounding widespread deployment of ‘autonomous machines’, but wrong to be so concerned about ...

Red-tailed Hawk movements and use of habitat in the Luquillo Mountains of Puerto Rico

Science.gov (United States)

Vilella, Francisco; Nimitz, Wyatt F.

2012-01-01

The Red-tailed Hawk (Buteo jamaicensis) is a top predator of upland ecosystems in the Greater Antilles. Little information exists on the ecology of the insular forms of this widely distributed species. We studied movements and resource use of the Red-tailed Hawk from 2000 to 2002 in the montane forests of northeastern Puerto Rico. We captured 32 and used 21 radio-marked Red-tailed Hawks to delineate home range, core area shifts, and macrohabitat use in the Luquillo Mountains. Red-tailed Hawks in the Luquillo Mountains frequently perched near the top of canopy emergent trees and were characterized by wide-ranging capabilities and extensive spatial overlap. Home range size averaged 5,022.6 6 832.1 ha (305–11,288 ha) and core areas averaged 564.8 6 90.7 ha (150–1,230 ha). This species had large mean weekly movements (3,286.2 6 348.5 m) and a preference for roadside habitats. Our findings suggest fragmentation of contiguous forest outside protected areas in Puerto Rico may benefit the Red-tailed Hawk

2016-2017 Travel Expense Report for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Beata Bialic

. Destination(s):. Saskatchewan. Airfare: $933.24. Other. Transportation: $89.13. Accommodation: $546.67. Meals and. Incidentals: $254.65. Other: $0.00. Total: $1,823.69. Comments: 2016-2017 Travel Expense Report for Stephen. McGurk ...

Entanglement in a model for Hawking radiation: An application of quadratic algebras

International Nuclear Information System (INIS)

Bambah, Bindu A.; Mukku, C.; Shreecharan, T.; Siva Prasad, K.

2013-01-01

Quadratic polynomially deformed su(1,1) and su(2) algebras are utilized in model Hamiltonians to show how the gravitational system consisting of a black hole, infalling radiation and outgoing (Hawking) radiation can be solved exactly. The models allow us to study the long-time behaviour of the black hole and its outgoing modes. In particular, we calculate the bipartite entanglement entropies of subsystems consisting of (a) infalling plus outgoing modes and (b) black hole modes plus the infalling modes, using the Janus-faced nature of the model. The long-time behaviour also gives us glimpses of modifications in the character of Hawking radiation. Finally, we study the phenomenon of superradiance in our model in analogy with atomic Dicke superradiance. - Highlights: ► We examine a toy model for Hawking radiation with quantized black hole modes. ► We use quadratic polynomially deformed su(1,1) algebras to study its entanglement properties. ► We study the “Dicke Superradiance” in black hole radiation using quadratically deformed su(2) algebras. ► We study the modification of the thermal character of Hawking radiation due to quantized black hole modes.

Stable occupancy by breeding hawks (Buteo spp.) over 25 years on a privately managed bunchgrass prairie in northeastern Oregon, USA

Science.gov (United States)

Kennedy, Patricia L.; Bartuszevige, Anne M.; Houle, Marcy; Humphrey, Ann B.; Dugger, Katie M.; Williams, John

2014-01-01

Potential for large prairie remnants to provide habitat for grassland-obligate wildlife may be compromised by nonsustainable range-management practices. In 1979–1980, high nesting densities of 3 species of hawks in the genus Buteo—Ferruginous Hawk (Buteo regalis), Red-tailed Hawk (B. jamaicensis), and Swainson's Hawk (B. swainsoni)—were documented on the Zumwalt Prairie and surrounding agricultural areas (34,361 ha) in northeastern Oregon, USA. This area has been managed primarily as livestock summer range since it was homesteaded. Unlike in other prairie remnants, land management on the Zumwalt Prairie was consistent over the past several decades; thus, we predicted that territory occupancy of these 3 species would be stable. We also predicted that territory occupancy would be positively related to local availability of nesting structures within territories. We evaluated these hypotheses using a historical dataset, current survey and habitat data, and occupancy models. In support of our predictions, territory occupancy of all 3 species has not changed over the study period of ∼25 yr, which suggests that local range-management practices are not negatively affecting these taxa. Probability of Ferruginous Hawk occupancy increased with increasing area of aspen, an important nest structure for this species in grasslands. Probability of Swainson's Hawk occupancy increased with increasing area of large shrubs, and probability of Red-tailed Hawk occupancy was weakly associated with area of conifers. In the study area, large shrubs and conifers are commonly used as nesting structures by Swainson's Hawks and Red-tailed Hawks, respectively. Availability of these woody species is changing (increases in conifers and large shrubs, and decline in aspen) throughout the west, and these changes may result in declines in Ferruginous Hawk occupancy and increases in Swainson's Hawk and Red-tailed Hawk occupancy in the future.

ATYPICAL CHLAMYDIACEAE IN WILD POPULATIONS OF HAWKS ( BUTEO SPP.) IN CALIFORNIA.

Science.gov (United States)

Luján-Vega, Charlene; Hawkins, Michelle G; Johnson, Christine K; Briggs, Christopher; Vennum, Chris; Bloom, Peter H; Hull, Joshua M; Cray, Carolyn; Pesti, Denise; Johnson, Lisa; Ciembor, Paula; Ritchie, Branson R

2018-03-01

Chlamydiaceae bacteria infect many vertebrate hosts, and previous reports based on polymerase chain reaction (PCR) assays and serologic assays that are prone to cross-reaction among chlamydial organisms have been used to describe the prevalence of either DNA fragments or antibodies to Chlamydia spp. in wild raptorial populations. This study reports the PCR-based prevalence of Chlamydiaceae DNA that does not 100% match any avian or mammalian Chlamydiaceae in wild populations of hawks in California Buteo species. In this study, multimucosal swab samples ( n = 291) for quantitative PCR (qPCR) and plasma ( n = 78) for serology were collected from wild hawks. All available plasma samples were negative for antibodies using a C. psittaci-specific elementary body agglutination test (EBA; n = 78). For IgY antibodies all 51 available samples were negative using the indirect immunofluorescent assay. The overall prevalence of Chlamydiaceae DNA detection in wild Buteo species sampled was 1.37% (4/291) via qPCR-based analysis. Two fledgling Swainson's hawks ( Buteo swainsoni) and two juvenile red-tailed hawks ( Buteo jamaicensis) were positive by qPCR-based assay for an atypical chlamydial sequence that did not 100% match any known C. psittaci genotype. Positive swab samples from these four birds were sequenced based on the ompA gene and compared by high-resolution melt analysis with all known avian and mammalian Chlamydiaceae. The amplicon sequence did not 100% match any known avian chlamydial sequence; however, it was most similar (98.6%) to C. psittaci M56, a genotype that is typically found in muskrats and hares. Culture and full genome sequence analysis of Chlamydia spp. isolated from diseased hawks will be necessary to classify this organism and to better understand its epizootiology and potential health impact on wild Buteo populations in California.

2016-2017 Hospitality Expense Report for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Chantal Taylor

Description: Dinner to discuss IDRC's programming with foreign official. Date: 2017-03-21. Attendees: 3 (IDRC 1). Location: Ottawa. Total: $66.29. Comments: 2016-2017 Hospitality Expense Report for. Stephen McGurk, Vice-President, Programs and Partnership Branch.

Thermodynamics and Hawking radiation of five-dimensional rotating charged Goedel black holes

International Nuclear Information System (INIS)

Wu Shuangqing; Peng Junjin

2011-01-01

We study the thermodynamics of Goedel-type rotating charged black holes in five-dimensional minimal supergravity. These black holes exhibit some peculiar features such as the presence of closed timelike curves and the absence of a globally spatial-like Cauchy surface. We explicitly compute their energies, angular momenta, and electric charges that are consistent with the first law of thermodynamics. Besides, we extend the covariant anomaly cancellation method, as well as the approach of the effective action, to derive their Hawking fluxes. Both the methods of the anomaly cancellation and the effective action give the same Hawking fluxes as those from the Planck distribution for blackbody radiation in the background of the charged rotating Goedel black holes. Our results further support that Hawking radiation is a quantum phenomenon arising at the event horizon.

Empty black holes, firewalls, and the origin of Bekenstein-Hawking entropy

Science.gov (United States)

Saravani, Mehdi; Afshordi, Niayesh; Mann, Robert B.

2014-01-01

We propose a novel solution for the endpoint of gravitational collapse, in which spacetime ends (and is orbifolded) at a microscopic distance from black hole event horizons. This model is motivated by the emergence of singular event horizons in the gravitational aether theory, a semiclassical solution to the cosmological constant problem(s) and thus suggests a catastrophic breakdown of general relativity close to black hole event horizons. A similar picture emerges in fuzzball models of black holes in string theory, as well as the recent firewall proposal to resolve the information paradox. We then demonstrate that positing a surface fluid in thermal equilibrium with Hawking radiation, with vanishing energy density (but nonvanishing pressure) at the new boundary of spacetime, which is required by Israel junction conditions, yields a thermodynamic entropy that is identical to the Bekenstein-Hawking area law, SBH, for charged rotating black holes. To our knowledge, this is the first derivation of black hole entropy that only employs local thermodynamics. Furthermore, a model for the microscopic degrees of freedom of the surface fluid (which constitute the microstates of the black hole) is suggested, which has a finite, but Lorentz-violating, quantum field theory. Finally, we comment on the effects of physical boundary on Hawking radiation and show that relaxing the assumption of equilibrium with Hawking radiation sets SBH as an upper limit for Black Hole entropy.

The potential role of oral pH in the persistence of Trichomonas gallinae in Cooper's Hawks (Accipiter cooperii).

Science.gov (United States)

Urban, Elizabeth H; Mannan, R William

2014-01-01

Trichomoniasis, caused by the protozoan Trichomonas gallinae, affects a variety of species worldwide including avivorious raptors. Existing information suggests that the disease is most prevalent in young birds, and differential susceptibility to trichomoniasis among individuals in different age groups was documented in Cooper's Hawks (Accipiter cooperii) nesting in Tucson, Arizona. In that population, 85% of nestling Cooper's Hawks had T. gallinae in their oral cavity, compared to only 1% of breeding-age hawks. Trichomonads generally are sensitive to environmental pH and we explored the possibility that differences in oral pH may contribute to the differential prevalence of infection between age groups. We measured the pH of the fluid in the oral cavity in 375 Cooper's Hawks from three age groups (nestlings, fledglings, and breeding age) in Tucson, Arizona, in 2010 and 2011 and clinically tested for T. gallinae in a subsample of hawks. Oral pH of nestlings (∼ 6.8) was 7.3 times less acidic than in fledgling or breeding Cooper's Hawks (∼ 6.1). The incidence of T. gallinae was higher in nestlings (16%) than in either fledglings or breeding hawks (0%). Our findings indicate that oral pH becomes more acidic in Cooper's Hawks soon after they leave the nest. Trichomonas gallinae thrives when pH is between 6.5 and 7.5 (optimum 7.2), but is less viable in more acidic conditions. Higher levels of acidity in the oral cavity of fledglings and breeding Cooper's Hawks may reduce their susceptibility to trichomoniasis, and play a role in the differential prevalence of infection among age groups.

THE JAMES MADISON WOOD QUADRANGLE, STEPHENS COLLEGE, COLUMBIA, MISSOURI.

Science.gov (United States)

MCBRIDE, WILMA

THE JAMES MADISON WOOD QUADRANGLE AT STEPHENS COLLEGE IS A COMPLEX OF BUILDINGS DESIGNED TO MAKE POSSIBLE A FLEXIBLE EDUCATIONAL ENVIRONMENT. A LIBRARY HOUSES A GREAT VARIETY OF AUDIO-VISUAL RESOURCES AND BOOKS. A COMMUNICATION CENTER INCORPORATES TELEVISION AND RADIO FACILITIES, A FILM PRODUCTION STUDIO, AND AUDIO-VISUAL FACILITIES. THE LEARNING…

Weight for Stephen Finlay.

Science.gov (United States)

Evers, Daan

2013-04-01

According to Stephen Finlay, ' A ought to X ' means that X -ing is more conducive to contextually salient ends than relevant alternatives. This in turn is analysed in terms of probability. I show why this theory of 'ought' is hard to square with a theory of a reason's weight which could explain why ' A ought to X ' logically entails that the balance of reasons favours that A X -es. I develop two theories of weight to illustrate my point. I first look at the prospects of a theory of weight based on expected utility theory. I then suggest a simpler theory. Although neither allows that ' A ought to X ' logically entails that the balance of reasons favours that A X -es, this price may be accepted. For there remains a strong pragmatic relation between these claims.

Hawk and Handsaw

Science.gov (United States)

Usher, Peter D.

2008-05-01

In Shakespeare's Hamlet, Prince Hamlet states, "I am but mad north-north-west. When the wind is southerly, I know a hawk from a handsaw." This celebrated yet perennially baffling passage is readily understood in the context of the cosmic allegorical interpretation of the play (BAAS 28, 1305, 1996; Hamlet's Universe, 2006). The first direction points from Tycho Brahe's observatory on Hven to the fictional home of the geocentric Pyolemaic worldview at Elsinore, and the second from Hven to the home of Copernican heliocentricism at Wittenberg. The directions correspond to the two influences on Tycho's geo-heliocentric World model. Anyone at Elsinore who advocates the new organon of the New Philosophy is "mad," whereas sanity prevails at Wittenberg. "Hawk" refers to a bird of prey, the leonard, and to Leonard Digges, inventor of the world's first two-element telescope. "Handsaw" refers to the artistic tool necessary to sever the hands depicted in de Gheyn's two quasi-mirror-imaged portraits of Tycho at age 40, which show hands affixed to the wrong arms. Elsewhere in Hamlet, Shakespeare substantiates the New Astronomy through descriptions of planets and stars that could only have been determined telescopically. Therefore, the passage in question contrasts two modes of observing in the early modern era, viz. visual and telescopic. Shakespeare completed writing Hamlet in about 1601 and the Second Quarto appeared in 1604, so the first substantial account of astronomical telescopy is now over 400 years old. In addition, 432 years ago Thomas Digges published the first account of the New Astronomy in a popular almanac. These two means of presentation may seem odd by present standards, but contemporary culture was intolerant of 'natural magic,' and furthermore, it was prudent to minmize the risk of domestic persecution and threats from Continental armies and the European and Spanish Inquisitions.

Hawking Radiation-Quasinormal Modes Correspondence for Large AdS Black Holes

Directory of Open Access Journals (Sweden)

Dao-Quan Sun

2017-01-01

Full Text Available It is well-known that the nonstrictly thermal character of the Hawking radiation spectrum generates a natural correspondence between Hawking radiation and black hole quasinormal modes. This main issue has been analyzed in the framework of Schwarzschild black holes, Kerr black holes, and nonextremal Reissner-Nordstrom black holes. In this paper, by introducing the effective temperature, we reanalyze the nonstrictly thermal character of large AdS black holes. The results show that the effective mass corresponding to the effective temperature is approximatively the average one in any dimension. And the other effective quantities can also be obtained. Based on the known forms of frequency in quasinormal modes, we reanalyze the asymptotic frequencies of the large AdS black hole in three and five dimensions. Then we get the formulas of the Bekenstein-Hawking entropy and the horizon’s area quantization with functions of the quantum “overtone” number n.

When does the Hawking into Unruh mapping for global embeddings work?

International Nuclear Information System (INIS)

Paston, S.A.

2014-01-01

We discuss for which smooth global embeddings of a metric into a Minkowskian spacetime the Hawking into Unruh mapping takes place. There is a series of examples of global embeddings into the Minkowskian spacetime (GEMS) with such mapping for physically interesting metrics. These examples use Fronsdal-type embeddings for which timelines are hyperbolas. In the present work we show that for some new embeddings (non Fronsdal-type) of the Schwarzschild and Reissner-Nordström metrics there is no mapping. We give also the examples of hyperbolic and non hyperbolic type embeddings for the de Sitter metric for which there is no mapping. For the Minkowski metric where there is no Hawking radiation we consider a non trivial embedding with hyperbolic timelines, hence in the ambient space the Unruh effect takes place, and it follows that there is no mapping too. The considered examples show that the meaning of the Hawking into Unruh mapping for global embeddings remains still insufficiently clear and requires further investigations.

Multivariate Hawkes process models of the occurrence of regulatory elements

DEFF Research Database (Denmark)

Carstensen, L; Sandelin, A; Winther, Ole

2010-01-01

distribution of the occurrences of these TREs along the genome. RESULTS: We present a model of TRE occurrences known as the Hawkes process. We illustrate the use of this model by analyzing two different publically available data sets. We are able to model, in detail, how the occurrence of one TRE is affected....... For each of the two data sets we provide two results: first, a qualitative description of the dependencies among the occurrences of the TREs, and second, quantitative results on the favored or avoided distances between the different TREs. CONCLUSIONS: The Hawkes process is a novel way of modeling the joint...

Entropy is conserved in Hawking radiation as tunneling: A revisit of the black hole information loss paradox

International Nuclear Information System (INIS)

Zhang Baocheng; Cai Qingyu; Zhan Mingsheng; You Li

2011-01-01

Research Highlights: → Information is found to be encoded and carried away by Hawking radiations. → Entropy is conserved in Hawking radiation. → We thus conclude no information is lost. → The dynamics of black hole may be unitary. - Abstract: We revisit in detail the paradox of black hole information loss due to Hawking radiation as tunneling. We compute the amount of information encoded in correlations among Hawking radiations for a variety of black holes, including the Schwarzchild black hole, the Reissner-Nordstroem black hole, the Kerr black hole, and the Kerr-Newman black hole. The special case of tunneling through a quantum horizon is also considered. Within a phenomenological treatment based on the accepted emission probability spectrum from a black hole, we find that information is leaked out hidden in the correlations of Hawking radiation. The recovery of this previously unaccounted for information helps to conserve the total entropy of a system composed of a black hole plus its radiations. We thus conclude, irrespective of the microscopic picture for black hole collapsing, the associated radiation process: Hawking radiation as tunneling, is consistent with unitarity as required by quantum mechanics.

George's secret key to the universe

CERN Document Server

Hawking, Lucy; Galfard, Christophe; Parsons, Gary

2007-01-01

In their bestselling book for young readers, noted physicist Stephen Hawking and his daughter, Lucy, provide a grand and funny adventure that explains fascinating information about our universe, including Dr. Hawking's latest ideas about black holes. It's the story of George, who's taken through the vastness of space by a scientist, his daughter, and their super-computer named Cosmos. George's Secret Key to the Universe was a New York Times bestseller and a selection of Al's Book Club on the Today show.

Migration and habitat preferences of Swainson's Hawks at an autumn stopover site in northwestern Texas

Science.gov (United States)

Littlefield, Carroll D.; Johnson, Douglas H.

2013-01-01

Unlike most raptors, the Swainson's Hawk (Buteo swainsoni) migrates long distances between breeding and wintering ranges, which elevates the importance of stopover sites for foraging. We conducted three years of fall surveys in the Southern High Plains of Texas. Migrant Swainson's Hawks moved through the area mostly between July and mid-October, peaking in September. Subadults tended to migrate earlier than adults, and light morphs before dark morphs. Favored foraging habitats included silage corn, green beans, and alfalfa, but the hawks foraged primarily where ongoing agricultural activities disturbed prey and made them more available.

Buteo Nesting Ecology: Evaluating Nesting of Swainson’s Hawks in the Northern Great Plains

Science.gov (United States)

Inselman, Will M.; Datta, Shubham; Jenks, Jonathan A.; Jensen, Kent C.; Grovenburg, Troy W.

2015-01-01

Swainson’s hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson’s hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson’s hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, S Dist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%–42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson’s hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson’s hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson’s hawks arriving to the breeding grounds. PMID:26327440

Hawking radiation as tunneling from the Kerr and Kerr-Newman black holes

International Nuclear Information System (INIS)

Jiang Qingqan; Wu Shuangqing; Cai Xu

2006-01-01

Recent work, which treats the Hawking radiation as a semiclassical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstroem spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory

Anomalies and Hawking fluxes from the black holes of topologically massive gravity

Energy Technology Data Exchange (ETDEWEB)

Porfyriadis, Achilleas P. [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)], E-mail: apporfyr@mit.edu

2009-05-11

The anomaly cancellation method proposed by Wilczek et al. is applied to the black holes of topologically massive gravity (TMG) and topologically massive gravito-electrodynamics (TMGE). Thus the Hawking temperature and fluxes of the ACL and ACGL black holes are found. The Hawking temperatures obtained agree with the surface gravity formula. Both black holes are rotating and this gives rise to appropriate terms in the effective U(1) gauge field of the reduced (1+1)-dimensional theory. It is found that the terms in this U(1) gauge field correspond exactly to the correct angular velocities on the horizon of both black holes as well as the correct electrostatic potential of the ACGL black hole. So the results for the Hawking fluxes derived here from the anomaly cancellation method, are in complete agreement with the ones obtained from integrating the Planck distribution.

HAWKING'S Theory of Quantum Cosmology

Science.gov (United States)

Zhi, Fang Li; Chao, Wu Zhong

The most important problem in cosmology is the birth of the universe. Recently Hartle and Hawking put forward a ground state proposal for the quantum state of the universe which incorporates the idea that the universe must come from nothing. Many models have been discussed in quantum cosmology with this boundary condition. It has been shown that every model is a step towards to a realistic universe, i.e. a 4-dimensional isotropic universe with a long inflationary stage.

Organophosphate insecticide (famphur) topically applied to cattle kills magpies and hawks

Science.gov (United States)

Henny, C.J.; Blus, L.J.; Kolbe, E.J.; Fitzner, R.E.

1985-01-01

A systematic field study of a black-billed magpie (P. pica) population revealed that magpies and red-tailed hawks (B. jamaicensis) were killed by famphur (= famophos, Warbex) used as a pour-on to control cattle warbles (Hypoderma sp.). Magpie mortality began on treatment day and continued for more than 3 mo. (38 found death); mortality peaked between Day 5 an Day 13. Estimates of magpie density (based on transects) decreased in both the control and treatment areas, but the decrease was greater in the treatment area. A red-tailed hawk found dead on Day 10 had eaten a famphur-contaminated magpie. Another red-tailed hawk was found alive but immobilized, and a 3rd died outside the study area. Brain cholinesterse (ChE) activity was 70-92% depressed in all dead birds examined; famphur residues were detected in all 17 magpies and the 2 hawks analyzed. The amount of famphur obtained by the dead magpies was estimated at 5.2-6.1 mg/kg (based on residue concentrations in the gizzard), which was above the acute oral LD50 for several bird species. The cow hair portion (12%) of the pooled gizzard contents from 13 other dead magpies produced extremely high famphur residues (4600 ppm). The residues persisted on cattle hair for more than 90 days post-treatment. Magpie populations in the far western states declined between 1968 and 1979, which corresponds with widespread use of famphur, although other factors may be involved.

2016-2017 Travel Expense Reports for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Chantal Taylor

Date(s):. 2017-02-10. Destination(s):. Toronto. Airfare: $765.29. Other. Transportation: $82.91. Accommodation: $0.00. Meals and. Incidentals: $61.60. Other: $0.00. Total: $909.80. Comments: 2016-2017 Travel Expense Reports for. Stephen McGurk, Vice-President, Programs and Partnership Branch.

A note on a perfect simulation algorithm for marked Hawkes processes

DEFF Research Database (Denmark)

Møller, Jesper; Rasmussen, Jakob Gulddahl

2004-01-01

The usual straightforward simulation algorithm for (marked or unmarked) Hawkes processes suffers from edge effect. In this note we describe a perfect simulation algorithm which is partly derived as in Brix and Kendall (2002) and partly using upper and lower processes as in the Propp......-Wilson algorithm (1996), or rather as in the dominated CFTP algorithm by Kendall and Moller (2000). Various monotonicity properties and approximations of the cumulative distribution function for the length of a so-called cluster in a marked Hawkes process play an important role....

Modulated Hawking radiation and a nonviolent channel for information release

Energy Technology Data Exchange (ETDEWEB)

Giddings, Steven B., E-mail: giddings@physics.ucsb.edu

2014-11-10

Unitarization of black hole evaporation requires that quantum information escapes a black hole; an important question is to identify the mechanism or channel by which it does so. Accurate counting of black hole states via the Bekenstein–Hawking entropy would indicate this information should be encoded in radiation with average energy flux matching Hawking's. Information can be encoded with no change in net flux via fine-grained modulation of the Hawking radiation. In an approximate effective field theory description, couplings to the stress tensor of the black hole atmosphere that depend on the internal state of the black hole are a promising alternative for inducing such modulation. These can be picturesquely thought of as due to state-dependent metric fluctuations in the vicinity of the horizon. Such couplings offer the prospect of emitting information without extra energy flux, and can be shown to do so at linear order in the couplings, with motivation given for possible extension of this result to higher orders. The potential advantages of such couplings to the stress tensor thus extend beyond their universality, which is helpful in addressing constraints from black hole mining.

Modulated Hawking radiation and a nonviolent channel for information release

International Nuclear Information System (INIS)

Giddings, Steven B.

2014-01-01

Unitarization of black hole evaporation requires that quantum information escapes a black hole; an important question is to identify the mechanism or channel by which it does so. Accurate counting of black hole states via the Bekenstein–Hawking entropy would indicate this information should be encoded in radiation with average energy flux matching Hawking's. Information can be encoded with no change in net flux via fine-grained modulation of the Hawking radiation. In an approximate effective field theory description, couplings to the stress tensor of the black hole atmosphere that depend on the internal state of the black hole are a promising alternative for inducing such modulation. These can be picturesquely thought of as due to state-dependent metric fluctuations in the vicinity of the horizon. Such couplings offer the prospect of emitting information without extra energy flux, and can be shown to do so at linear order in the couplings, with motivation given for possible extension of this result to higher orders. The potential advantages of such couplings to the stress tensor thus extend beyond their universality, which is helpful in addressing constraints from black hole mining

2013-2014 Expense report for Stephen McGurk | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

2013-2014 Expense report for Stephen McGurk. Travel and Hospitality Expenses 2013-2014 · What we do · Funding · Resources · About IDRC. Knowledge. Innovation. Solutions. Careers · Contact Us · Site map. Sign up now for IDRC news and views sent directly to your inbox each month. Subscribe · Copyright · Open ...

2014-2015 Expense report for Stephen McGurk | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

2014-2015 Expense report for Stephen McGurk. Travel and Hospitality Expenses 2014-2015 · What we do · Funding · Resources · About IDRC. Knowledge. Innovation. Solutions. Careers · Contact Us · Site map. Sign up now for IDRC news and views sent directly to your inbox each month. Subscribe · Copyright · Open ...

Comparison of transcoelomic, contrast transcoelomic, and transesophageal echocardiography in anesthetized red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Beaufrère, Hugues; Pariaut, Romain; Rodriguez, Daniel; Nevarez, Javier G; Tully, Thomas N

2012-10-01

To assess the agreement and reliability of cardiac measurements obtained with 3 echocardiographic techniques in anesthetized red-tailed hawks (Buteo jamaicensis). 10 red-tailed hawks. Transcoelomic, contrast transcoelomic, and transesophageal echocardiographic evaluations of the hawks were performed, and cineloops of imaging planes were recorded. Three observers performed echocardiographic measurements of cardiac variables 3 times on 3 days. The order in which hawks were assessed and echocardiographic techniques were used was randomized. Results were analyzed with linear mixed modeling, agreement was assessed with intraclass correlation coefficients, and variation was estimated with coefficients of variation. Significant differences were evident among the 3 echocardiographic methods for most measurements, and the agreement among findings was generally low. Interobserver agreement was generally low to medium. Intraobserver agreement was generally medium to high. Overall, better agreement was achieved for the left ventricular measurements and for the transesophageal approach than for other measurements and techniques. Echocardiographic measurements in hawks were not reliable, except when the left ventricle was measured by the same observer. Furthermore, cardiac morphometric measurements may not be clinically important. When measurements are required, one needs to consider that follow-up measurements should be performed by the same echocardiographer and should show at least a 20% difference from initial measurements to be confident that any difference is genuine.

Hawking radiation in a d-dimensional static spherically symmetric black hole surrounded by quintessence

International Nuclear Information System (INIS)

Chen Songbai; Wang Bin; Su Rukeng

2008-01-01

We present a solution of Einstein equations with quintessential matter surrounding a d-dimensional black hole, whose asymptotic structures are determined by the state of the quintessential matter. We examine the thermodynamics of this black hole and find that the mass of the black hole depends on the equation of state of the quintessence, while the first law is universal. Investigating the Hawking radiation in this black hole background, we observe that the Hawking radiation dominates on the brane in the low-energy regime. For different asymptotic structures caused by the equation of state of the quintessential matter surrounding the black hole, we learn that the influences by the state parameter of the quintessence on Hawking radiation are different

Exploring Stephen Krashen's "i+1" Acquisition Model in the Classroom

Science.gov (United States)

Payne, Mark

2011-01-01

Stephen Krashen's theories can appear "seductive" to teachers of languages, in that they identify a seemingly clear way forward for language acquisition in the classroom. However, reification of Krashen's theories, in particular the notion of attaining "i+1" through comprehensible input, is demonstrated to be problematic. Based…

The Blob That Ate Physics

Science.gov (United States)

Thomsen, Dietrick E.

1975-01-01

Summarizes some thoughts of Stephen W. Hawking who proposes that certain kinds of communications across the event horizon are possible, that they lead to the evaporation or explosion of the black hole, and, therefore, that classical or quantum mechanical causality has no meaning. (GS)

Biggest bets in the universe unveiled

CERN Multimedia

Jamieson, Valerie

2004-01-01

Betting on the greatest unsolved problems in the universe is no longer the preserve of academic superstars such as Stephen Hawking. From Thursday, anyone will be able to place bets on whether the biggest physics experiments in the world will come good before 2010

Comment on 'Hawking radiation from fluctuating black holes'

NARCIS (Netherlands)

Khavkine, I.

2010-01-01

Takahashi and Soda (2010 Class. Quantum Grav. 27 175008) have recently considered the effect (at lowest non-trivial order) of dynamical, quantized gravitational fluctuations on the spectrum of scalar Hawking radiation from a collapsing Schwarzschild black hole. However, due to an unfortunate choice

Declan FAHY (2015), The New Celebrity Scientists. Out of the Lab and into the Limelight

OpenAIRE

Fines-Neuschild, Mirjam

2016-01-01

The New Celebrity Scientists est le premier ouvrage de Declan Fahy. Il y fait le portrait de huit scientifiques en suivant leur parcours jusqu’à la célébrité et présente l’influence de leurs propos sur les politiques publiques. De ces huit scientifiques, trois sont physiciens : Stephen Hawking, Brian Greene et Neil de Grasse Tyson. Sont aussi présentés Richard Dawkins, biologiste, Steven Pinker, psychologue cognitiviste, Stephen Jay Gould, paléontologue, Susan Greenfield, pharmacologue, et Ja...

2016-2017 Travel Expense Report for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Beata Bialic

Purpose: Attend Canada-Israel Official Committee dinner. Date(s):. 2016-06-21. Destination(s):. Toronto. Airfare: $232.04. Other. Transportation: $118.84. Accommodation: $0.00. Meals and. Incidentals: $0.00. Other: $0.00. Total: $350.88. Comments: 2016-2017 Travel Expense Report for Stephen. McGurk, Vice-President ...

The Hawking effect in abelian gauge theories

International Nuclear Information System (INIS)

Stephens, C.R.

1989-01-01

In an effort to compare and contrast gravity with other field theories an investigation is made into whether the Hawking effect is a peculiarly gravitational phenomenon. It is found that the effect exists for a particular background abelian gauge field configuration, as well as certain background gravitational field configurations. Specifically, pair production in a uniform electric field is shown to admit a thermal interpretation. In an effort to find out just what is singular about gravity it is found that the Hawking temperature characteristic of a particular gravitational field configuration is independent of the properties of the quantum fields propagating theorem, in direct contrast to the gauge field case. This implies that if the one loop approximation is to be valid the electric field must be ''cold'' relative to the energy scales set by the quantum fields. In gravity, however, because of the existence of a fundamental scale, the Planck length, the gravitational field can be ''hot'' or ''cold'' and a one loop approximation still remain valid. copyright 1989 Academic Press, Inc

Mean-field inference of Hawkes point processes

International Nuclear Information System (INIS)

Bacry, Emmanuel; Gaïffas, Stéphane; Mastromatteo, Iacopo; Muzy, Jean-François

2016-01-01

We propose a fast and efficient estimation method that is able to accurately recover the parameters of a d-dimensional Hawkes point-process from a set of observations. We exploit a mean-field approximation that is valid when the fluctuations of the stochastic intensity are small. We show that this is notably the case in situations when interactions are sufficiently weak, when the dimension of the system is high or when the fluctuations are self-averaging due to the large number of past events they involve. In such a regime the estimation of a Hawkes process can be mapped on a least-squares problem for which we provide an analytic solution. Though this estimator is biased, we show that its precision can be comparable to the one of the maximum likelihood estimator while its computation speed is shown to be improved considerably. We give a theoretical control on the accuracy of our new approach and illustrate its efficiency using synthetic datasets, in order to assess the statistical estimation error of the parameters. (paper)

The effect of the Gauss-Bonnet term on Hawking radiation from arbitrary dimensional black brane

International Nuclear Information System (INIS)

Kuang, Xiao-Mei; Saavedra, Joel; Oevguen, Ali

2017-01-01

We investigate the probabilities of the tunneling and the radiation spectra of massive spin-1 particles from arbitrary dimensional Gauss-Bonnet-Axions (GBA) Anti-de Sitter (AdS) black branes, via using the WKB approximation to the Proca spin-1 field equation. The tunneling probabilities and Hawking temperature of the arbitrary dimensional GBA AdS black brane is calculated via the Hamilton-Jacobi approach. We also compute the Hawking temperature via the Parikh-Wilczek tunneling approach. The results obtained from the two methods are consistent. In our setup, the Gauss-Bonnet (GB) coupling affects the Hawking temperature if and only if the momentum of the axion fields is non-vanishing. (orig.)

The effect of the Gauss-Bonnet term on Hawking radiation from arbitrary dimensional black brane

Energy Technology Data Exchange (ETDEWEB)

Kuang, Xiao-Mei [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Yangzhou University, Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou (China); Saavedra, Joel [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Oevguen, Ali [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Eastern Mediterranean University, Physics Department, Famagusta, Northern Cyprus (Country Unknown)

2017-09-15

We investigate the probabilities of the tunneling and the radiation spectra of massive spin-1 particles from arbitrary dimensional Gauss-Bonnet-Axions (GBA) Anti-de Sitter (AdS) black branes, via using the WKB approximation to the Proca spin-1 field equation. The tunneling probabilities and Hawking temperature of the arbitrary dimensional GBA AdS black brane is calculated via the Hamilton-Jacobi approach. We also compute the Hawking temperature via the Parikh-Wilczek tunneling approach. The results obtained from the two methods are consistent. In our setup, the Gauss-Bonnet (GB) coupling affects the Hawking temperature if and only if the momentum of the axion fields is non-vanishing. (orig.)

Swainson's Hawk Survey Grid - DFG Region 2 [ds697

Data.gov (United States)

California Natural Resource Agency — 5 km x 5 km landscape blocks used for Ca. Dept. of Fish and Game central valley Swainson's hawk nest surveys since 2000, edited for 2009 surveys using the following...

The trilinear Hamiltonian: a zero-dimensional model of Hawking radiation from a quantized source

International Nuclear Information System (INIS)

Nation, Paul D; Blencowe, Miles P

2010-01-01

We investigate a quantum parametric amplifier with dynamical pump mode, viewed as a zero-dimensional model of Hawking radiation from an evaporating black hole. We derive the conditions under which the spectrum of particles generated from vacuum fluctuations deviates from the thermal spectrum predicted for the conventional parametric amplifier. We find that significant deviations arise when the pump mode (black hole) has emitted nearly half of its initial energy into the signal (Hawking radiation) and idler (in-falling particle) modes. As a model of black hole dynamics, this finding lends support to the view that late-time Hawking radiation contains information about the quantum state of the black hole and is entangled with the black hole's quantum gravitational degrees of freedom.

Hawking versus Unruh effects, or the difficulty of slowly crossing a black hole horizon

Energy Technology Data Exchange (ETDEWEB)

Barbado, Luis C. [Quantenoptik, Quantennanophysik und Quanteninformation, Fakultät für Physik,Universität Wien, Boltzmanngasse 5, 1090 Wien (Austria); Departamento de Astronomía Extragaláctica, Instituto de Astrofísica de Andalucía (CSIC),Glorieta de la Astronomía s/n, 18008 Granada (Spain); Barceló, Carlos [Departamento de Astronomía Extragaláctica, Instituto de Astrofísica de Andalucía (CSIC),Glorieta de la Astronomía s/n, 18008 Granada (Spain); Garay, Luis J. [Departamento de Física Teórica II, Facultad de Ciencias Fśicas,Universidad Complutense de Madrid, Ciudad Universitaria,Plaza Ciencias 1, 28040 Madrid (Spain); Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia (CSIC),Serrano 121, 28006 Madrid (Spain); Jannes, Gil [Departamento de Ciencias y Tecnología, Universidad Europea de Madrid,Calle Tajo s/n, 28670 Villaviciosa de Odón, Madrid (Spain)

2016-10-28

When analyzing the perception of Hawking radiation by different observers, the Hawking effect becomes mixed with the Unruh effect. The separation of both effects is not always clear in the literature. Here we propose an inconsistency-free interpretation of what constitutes a Hawking effect and what an Unruh effect. An appropriate interpretation is important in order to elucidate what sort of effects a detector might experience depending on its trajectory and the state of the quantum field. Under simplifying assumptions we introduce an analytic formula that separates these two effects. Armed with the previous interpretation we argue that for a free-falling detector to cross the horizon without experiencing high-energy effects, it is necessary that the horizon crossing is not attempted at low velocities.

Hawking radiation from the dilaton—(anti) de Sitter black hole via covariant anomaly

International Nuclear Information System (INIS)

Yi-Wen, Han; Yun, Hong; Zhi-Qing, Bao

2009-01-01

Adopting the anomaly cancellation method, initiated by Robinson and Wilczek recently, this paper discusses Hawking radiation from the dilaton—(anti) de Sitter black hole. To save the underlying gauge and general covariance, it introduces covariant fluxes of gauge and energy-momentum tensor to cancel the gauge and gravitational anomalies. The result shows that the introduced compensating fluxes are equivalent to those of a 2-dimensional blackbody radiation at Hawking temperature with appropriate chemical potential. (general)

Facing being: the significance of Thomist ontological epistemology ...

African Journals Online (AJOL)

An inevitable consequence of things not being knowable in themselves is the philosophical distance from 'the world', which Stephen Hawking has argued, makes the philosophical enterprise 'dead'. In dialogue with this widespread decline in metaphysics, I will attempt to reclaim realist metaphysics through the employment ...

Hawking from Catalan

Science.gov (United States)

Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; Wang, Junpu

2016-05-01

The Virasoro algebra determines all `graviton' matrix elements in AdS3/CFT2. We study the explicit exchange of any number of Virasoro gravitons between heavy and light CFT2 operators at large central charge. These graviton exchanges can be written in terms of new on-shell tree diagrams, organized in a perturbative expansion in h H /c, the heavy operator dimension divided by the central charge. The Virasoro vacuum conformal block, which is the sum of all the tree diagrams, obeys a differential recursion relation generalizing that of the Catalan numbers. We use this recursion relation to sum the on-shell diagrams to all orders, computing the Virasoro vacuum block. Extrapolating to large h H /c determines the Hawking temperature of a BTZ black hole in dual AdS3 theories.

An interview with: Stephen Paliska on valet parking.

Science.gov (United States)

Paliska, S

1993-04-01

Stephen Paliska is general manager and co-founder, with his brother, Paul, of Professional Parking Services, Inc., based in Irvine, CA. The company has been in operation for eight years. PPS's 600 valets provide parking services for more than 80 clients, including hotels, shopping centers, restaurants, and hospitals. In this interview, Paliska discusses the benefits and some potential risks of valet parking and spells out how a training program for valet attendants should be carried out.

2016-2017 Travel Expense Report for Stephen McGurk, Vice ...

International Development Research Centre (IDRC) Digital Library (Canada)

Beata Bialic

Purpose: Attend meeting on Food Security. Date(s):. 2016-04-03 to 2016-04-06. Destination(s):. Saskatchewan. Airfare: $1,180.62. Other. Transportation: $79.31. Accommodation: $375.60. Meals and. Incidentals: $188.19. Other: $0.00. Total: $1,823.72. Comments: 2016-2017 Travel Expense Report for. Stephen McGurk ...

Reconsidering the Role of Stephen Foster in the Music Classroom

Science.gov (United States)

Forness, Jennifer

2016-01-01

The place of Stephen Foster and the music of American minstrelsy should be reconsidered for the music classroom. Some of this repertoire can be offensive because of its historical context and racially insensitive language. Critical theory can provide a framework for choosing repertoire that creates dialogue about racial structures in music. The…

Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole

Energy Technology Data Exchange (ETDEWEB)

Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)

2015-09-15

We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.

Testing the causality of Hawkes processes with time reversal

Science.gov (United States)

Cordi, Marcus; Challet, Damien; Muni Toke, Ioane

2018-03-01

We show that univariate and symmetric multivariate Hawkes processes are only weakly causal: the true log-likelihoods of real and reversed event time vectors are almost equal, thus parameter estimation via maximum likelihood only weakly depends on the direction of the arrow of time. In ideal (synthetic) conditions, tests of goodness of parametric fit unambiguously reject backward event times, which implies that inferring kernels from time-symmetric quantities, such as the autocovariance of the event rate, only rarely produce statistically significant fits. Finally, we find that fitting financial data with many-parameter kernels may yield significant fits for both arrows of time for the same event time vector, sometimes favouring the backward time direction. This goes to show that a significant fit of Hawkes processes to real data with flexible kernels does not imply a definite arrow of time unless one tests it.

Anticoagulant rodenticides in red-tailed hawks, Buteo jamaicensis, and great horned owls, Bubo virginianus, from New Jersey, USA, 2008-2010.

Science.gov (United States)

Stansley, William; Cummings, Margaret; Vudathala, Daljit; Murphy, Lisa A

2014-01-01

Liver samples from red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus) were analyzed for anticoagulant rodenticides. Residues of one or more second generation anticoagulant rodenticides (SGARs) were detected in 81 % of red-tailed hawks and 82 % of great horned owls. The most frequently detected SGAR was brodifacoum, which was detected in 76 % of red-tailed hawks and 73 % of great horned owls. Bromadiolone was detected in 20 % of red-tailed hawks and 27 % of great horned owls. Difenacoum was detected in one great horned owl. No other ARs were detected. There were no significant differences between species in the frequency of detection or concentration of brodifacoum or bromadiolone. There was a marginally significant difference (p = 0.0497) between total SGAR residues in red-tailed hawks (0.117 mg/kg) and great horned owls (0.070 mg/kg). There were no seasonal differences in the frequency of detection or concentration of brodifacoum in red-tailed hawks. The data suggest that SGARs pose a significant risk of poisoning to predatory birds in New Jersey.

STEPHEN CRANE'S "THE O'RUDDY"--A PROBLEM IN AUTHORSHIP DISCRIMINATION.

Science.gov (United States)

O'DONNELL, BERNARD

THE PURPOSE OF THIS ANALYSIS WAS TO DISCOVER CERTAIN ASPECTS OF STYLE (BOTH LEXICAL AND GRAMMATICAL) WHICH COULD BE COUNTED AND WHICH WOULD, WHEN COMPARED, DIFFERENTIATE BETWEEN THE WRITTEN PROSE OF TWO AUTHORS. THE SUBJECT SELECTED FOR ANALYSIS WAS "THE O'RUDDY," BEGUN BY STEPHEN CRANE AND COMPLETED BY ROBERT BARR. SINCE THERE WAS NO…

Shifts in the field of mathematics education Stephen Lerman and the turn to the social

CERN Document Server

Gates, Peter

2014-01-01

Professor Stephen Lerman has been a leader in the field of mathematics education for thirty years. His work is extensive, making many significant contributions to a number of key areas of research. Stephen retired from South Bank University in 2012, where he had worked for over 20 years, though he continues to work at Loughborough University. In this book several of his long standing colleagues and collaborators reflect on his contribution to mathematics education, and in so doing illustrate how some of Steve's ideas and interventions have resulted in significant shifts in the domain.

Mental Imagery in Creative Problem Solving.

Science.gov (United States)

Polland, Mark J.

In order to investigate the relationship between mental imagery and creative problem solving, a study of 44 separate accounts reporting mental imagery experiences associated with creative discoveries were examined. The data included 29 different scientists, among them Albert Einstein and Stephen Hawking, and 9 artists, musicians, and writers,…

Larry Echo Hawk: A Rising Star from Idaho.

Science.gov (United States)

Wisecarver, Charmaine

1993-01-01

Larry Echo Hawk, Idaho attorney general and former state legislator, discusses success factors in college and law school; early experiences as an Indian lawyer; first election campaign; and his views on tribal sovereignty, state-tribal relationship, gambling, and his dual responsibility to the general public and Native American issues. (SV)

On the Character Trait of Stephen Dedalus in A Portrait of the Artist as a Young Man

Institute of Scientific and Technical Information of China (English)

HU Meng-qiao

2017-01-01

A Portrait of the Artist as a Young Man is the first novel of stream of consciousness in western literature history, it mainly shows the protagonist, Stephen Dedalus's journeys from childhood to adulthood. This paper aims at a better understand-ing of Stephen Dedalus, and it analyzes his character traits in literature analysis method, textual analysis method and Freud's theory of personality structure and is useful for further study.

Ühisjooned sillutavad koostööd / Stephen Ip ; interv. Kristo Kiviorg

Index Scriptorium Estoniae

Ip, Stephen

2007-01-01

Ilmunud ka: Delovõje Vedomosti 20. juuni lk. 13. Hongkongi erihaldusregiooni majandus- ja tööhõiveminister Stephen Ip vastab küsimustele Eesti ja Hongkongi vahelise logistikakoostöö võimaluste kohta. Kommenteerib Elar Kilumets

Probing the quantum correlation and Bell non-locality for Dirac particles with Hawking effect in the background of Schwarzschild black hole

International Nuclear Information System (INIS)

Xu, Shuai; Song, Xue-ke; Shi, Jia-dong; Ye, Liu

2014-01-01

In this Letter, we analytically explore the effect of the Hawking radiation on the quantum correlation and Bell non-locality for Dirac particles in the background of Schwarzschild black hole. It is shown that when the Hawking effect is almost nonexistent, corresponding to the case of an almost extreme black hole, the quantum properties of physically accessible state are the same for the initial situation. For finite Hawking temperature T, the accessible quantum correlation monotonously decreases along with increasing T owing to the thermal fields generated by the Hawking effect, and the accessible quantum non-locality will be disappeared when the Hawking temperature is more than a fixed value which increases with the parameter r of Werner state growing. Then we analyze the redistribution of quantum correlation, and find that for the case of the Hawking temperature being infinite, corresponding to the case of the black hole evaporating completely, the quantum correlation of physically accessible state is equal to the one of the inaccessible states. Moreover, due to the Pauli exclusion principle and the differences between Fermi–Dirac and Bose–Einstein statistics, for the Dirac fields the accessible classical correlation decreases with increase of the Hawking temperature, which is different for the scalar fields. For Bell non-locality, we also find that the quantum non-locality is always extinct for physically inaccessible states, and the strength of the non-locality decreases with enlarging intensity of Hawking effect when the non-locality is existent in physically accessible state.

On the limits of application of the Stephens model

International Nuclear Information System (INIS)

Issa, A.; Piepenbring, R.

1977-01-01

The limits of the rotation alignment model of Stephens are studied. The conditions of applicability of the assumption of constant j for a unique parity isolated sub-shell (extended to N=4 and N=3) are discussed and explanations are given. A correct treatment of the eigenstates of the intrinsic motion allows however a simple extension of the model to non-isolated sub-shells without enlarging the basis of diagonalisation [fr

Hawking radiation from a spherical loop quantum gravity black hole

International Nuclear Information System (INIS)

Gambini, Rodolfo; Pullin, Jorge

2014-01-01

We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step toward studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space-time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back-reaction calculations in more traditional treatments. The discreteness of area leads to modifications of the quantum vacua, eliminating the trans-Planckian modes close to the horizon, which in turn eliminates all singularities from physical quantities, like the expectation value of the stress–energy tensor. Apart from this, the Boulware, Hartle–Hawking and Unruh vacua differ little from the treatment on a classical space-time. The asymptotic modes near scri are reproduced very well. We show that the Hawking radiation can be computed, leading to an expression similar to the conventional one but with a high frequency cutoff. Since many of the conclusions concern asymptotic behavior, where the spherical mode of the field behaves in a similar way as higher multipole modes do, the results can be readily generalized to non spherically symmetric fields. (paper)

Ambiguity of the equivalence principle and Hawking's temperature

NARCIS (Netherlands)

Hooft, G. 't

1984-01-01

There are two inequivalent ways in which the laws of physics in a gravitational field can be related to the laws in an inertial frame, when quantum mechanical effects are taken into account. This leads to an ambiguity in the derivation of Hawking's radiation temperature for a black hole: it could be

Soft hair of dynamical black hole and Hawking radiation

Science.gov (United States)

Chu, Chong-Sun; Koyama, Yoji

2018-04-01

Soft hair of black hole has been proposed recently to play an important role in the resolution of the black hole information paradox. Recent work has emphasized that the soft modes cannot affect the black hole S-matrix due to Weinberg soft theorems. However as soft hair is generated by supertranslation of geometry which involves an angular dependent shift of time, it must have non-trivial quantum effects. We consider supertranslation of the Vaidya black hole and construct a non-spherical symmetric dynamical spacetime with soft hair. We show that this spacetime admits a trapping horizon and is a dynamical black hole. We find that Hawking radiation is emitted from the trapping horizon of the dynamical black hole. The Hawking radiation has a spectrum which depends on the soft hair of the black hole and this is consistent with the factorization property of the black hole S-matrix.

Analogy of QCD hadronization and Hawking-Unruh radiation at NICA

Energy Technology Data Exchange (ETDEWEB)

Nasser Tawfik, Abdel [Modern University for Technology and Information (MTI), Egyptian Center for Theoretical Physics (ECTP), Cairo (Egypt); World Laboratory for Cosmology And Particle Physics (WLCAPP), Cairo (Egypt); Academy for Scientific Research and Technology (ASRT), Network for Nuclear Sciences (NNS), Cairo (Egypt)

2016-08-15

The proposed analogy of particle production from high-energy collisions and Hawking-Unruh radiation from black holes is extended to finite density (collisions) and finite electric charge (black holes). Assuming that the electric charge is directly proportional to the density (or the chemical potential), it becomes clear that for at least two freezeout conditions; constant s/T{sup 3} and E/N, the proposed analogy works very well. Dependence of radiation (freezeout) temperature on finite electric charge leads to an excellent estimation for kaon-to-pion ratio, for instance, especially in the energy range covered by NICA. The precise and complete measurements for various light-flavored particle yields and ratios are essential in characterizing Hawking-Unruh radiation from charged black holes and the QCD hadronization at finite density, as well. (orig.)

Science Fiction Movies as a Tool for Revealing Students' Knowledge and Alternative Conceptions

Science.gov (United States)

Ongel-Erdal, Sevinc; Sonmez, Duygu; Day, Rob

2004-01-01

According to renowned physicist Stephen Hawking, "science fiction is useful both for stimulating the imagination and for diffusing fear of the future." Indeed, several studies suggest that using science fiction movies as a teaching aid can improve both motivation and achievement. However, if a movie's plot crosses the line between good…

Certainty is Illusion: The Myth of Strategic Guidance

Science.gov (United States)

2015-06-21

You’re very clever, young man . . . but it’s turtles all the way down!” Stephen W. Hawking, A Brief History of Time: From the Big Bang to Black...an antecedent, completed strategy. The dominant theory of political-military relations, espoused by Samuel Huntington in The Soldier and the State

"Ich war nicht der allmächtige Autor" / Simon Stephens ; intervjueerinud Jacqueline Bolton

Index Scriptorium Estoniae

Stephens, Simon, 1971-

2012-01-01

NO99 teatris esietendunud kolme teatri - NO99, Münchner Kammerspiele, Lyric Hammersmith Theatre - koostöös valminud lavastuse "Three Kingdoms" ("Kolm kuningriiki") teksti autor Simon Stephens räägib

STS-110 Crew Interview: Stephen Frick

Science.gov (United States)

2002-01-01

STS-110 Pilot Stephen Frick is seen during this preflight interview, where he gives a quick overview of the mission before answering questions about his inspiration to become an astronaut and his career path. Frick outlines his role in the mission in general, and specifically during the docking and extravehicular activities (EVAs). He describes the payload (S0 Truss and Mobile Transporter) and the dry run installation of the S0 truss that will take place the day before the EVA for the actual installation. Frick discusses the planned EVAs in detail and outlines what supplies will be left for the resident crew of the International Space Station (ISS). He ends with his thoughts on the most valuable aspect of the ISS.

Between Traditions: Stephen Ball and the Critical Sociology of Education

Science.gov (United States)

Apple, Michael W.

2013-01-01

Stephen Ball's work has deservedly received a good deal of attention. In this article, I detail a number of tasks in which the critical sociologist of education--as a "public intellectual"--should engage. I then place Ball's work within these tasks and evaluate his contributions to them. In the process, I show that one of the…

Hawking radiation from rotating black holes in anti-de Sitter spaces via gauge and gravitational anomalies

International Nuclear Information System (INIS)

Jiang Qingquan; Wu Shuangqing

2007-01-01

Robinson-Wilczek's recent work, which treats Hawking radiation as a compensating flux to cancel gravitational anomaly at the horizon of a Schwarzschild-type black hole, is extended to study Hawking radiation of rotating black holes in anti-de Sitter spaces, especially that in dragging coordinate system, via gauge and gravitational anomalies. The results show that in order to restore gauge invariance and general coordinate covariance at the quantum level in the effective field theory, the charge and energy flux by requiring to cancel gauge and gravitational anomalies at the horizon, must have a form equivalent to that of a (1+1)-dimensional blackbody radiation at Hawking temperature with an appropriate chemical potential

Hawking radiation as tunneling from the event horizon of NUT-Kerr-Newman de Sitter black hole

International Nuclear Information System (INIS)

Hui-Ling, Li; Shu-Shenh, Yang; Qing-Quan, Jiang; De-Jiang, Qi

2005-01-01

Adopting the method of quantum radiation as tunneling, Hawking radiation as tunneling from the event horizon of NUT-Kerr-Newman de Sitter black hole is studied. The result indicates that the tunneling rate of the particle on the event horizon is related to the change of Bekenstein-Hawking entropy and the real spectrum is not strictly thermal at all

Hawking radiation via anomaly cancellation for the black holes of five-dimensional minimal gauged supergravity

International Nuclear Information System (INIS)

Porfyriadis, Achilleas P.

2009-01-01

The anomaly cancellation method proposed by Wilczek et al. is applied to the general charged rotating black holes in five-dimensional minimal gauged supergravity. Thus Hawking temperature and fluxes are found. The Hawking temperature obtained agrees with the surface gravity formula. The black holes have charge and two unequal angular momenta, and these give rise to appropriate terms in the effective U(1) gauge field of the reduced (1+1)-dimensional theory. In particular, it is found that the terms in this U(1) gauge field correspond exactly to the correct electrostatic potential and the two angular velocities on the horizon of the black holes, and so the results for the Hawking fluxes derived here from the anomaly cancellation method are in complete agreement with the ones obtained from integrating the Planck distribution.

DPPH Radical Scavenging and Postprandial Hyperglycemia Inhibition Activities and Flavonoid Composition Analysis of Hawk Tea by UPLC-DAD and UPLC-Q/TOF MSE.

Science.gov (United States)

Xiao, Xuan; Xu, Lijia; Hu, Huagang; Yang, Yinjun; Zhang, Xinyao; Peng, Yong; Xiao, Peigen

2017-10-13

Hawk tea ( Litsea coreana Lévl. var. Lanuginosa (Migo) Yen C. Yang & P.H. Huang), a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT), primary leaf tea (PLT) and mature leaf tea (MLT). In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD) method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME) of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE), ethyl acetate fraction (EA), n -butanol fraction ( n -BuOH), and water fraction (WF)) on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg) group and the high dose (1 g/kg) group with oral administration of the ME of PLT were significantly lower than the control group. What's more, the inhibitory effect of ME of PLT and its EA and n -BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS) was used to identify the flavonoids in Hawk PLT, and a total of 20

Hormonal underpinnings of status conflict: Testosterone and cortisol are related to decisions and satisfaction in the hawk-dove game.

Science.gov (United States)

Mehta, Pranjal H; Lawless DesJardins, Nicole M; van Vugt, Mark; Josephs, Robert A

2017-06-01

A contribution to a special issue on Hormones and Human Competition.Testosterone is theorized to influence status-seeking behaviors such as social dominance and competitive behavior, but supporting evidence is mixed. The present study tested the roles of testosterone and cortisol in the hawk-dove game, a dyadic economic decision-making paradigm in which earnings depend on one's own and the other player's choices. If one person selects the hawk strategy and the other person selects the dove strategy, the player who selected hawk attains a greater financial pay-off (status differentiation). The worst financial outcome occurs when both players choose the hawk strategy (status confrontation). Ninety-eight undergraduate students (42 men) provided saliva samples and played ten rounds of the hawk-dove game with another same-sex participant. In support of the hypothesis that testosterone is related to status concern, individuals higher in basal testosterone made more hawk decisions - decisions that harmed the other player. Acute decreases in cortisol were also associated with more hawk decisions. There was some empirical support for the dual-hormone hypothesis as well: basal testosterone was positively related to satisfaction in the game among low basal-cortisol individuals but not among high basal-cortisol individuals. There were no significant sex differences in these hormonal effects. The present findings align with theories of hormones and status-seeking behavior at the individual level, but they also open up new avenues for research on hormone profiles at the collective level. Our results suggest that the presence of two or more high-testosterone members increases the likelihood of status confrontations over a limited resource that can undermine collective outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Pharmacokinetics of a concentrated buprenorphine formulation in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Gleeson, Molly D; Guzman, David Sanchez-Migallon; Knych, Heather K; Kass, Philip H; Drazenovich, Tracy L; Hawkins, Michelle G

2018-01-01

OBJECTIVE To determine the pharmacokinetics and sedative effects of 2 doses of a concentrated buprenorphine formulation after SC administration to red-tailed hawks (Buteo jamaicensis). ANIMALS 6 adult red-tailed hawks. PROCEDURES Concentrated buprenorphine (0.3 mg/kg, SC) was administered to all birds. Blood samples were collected at 10 time points over 24 hours after drug administration to determine plasma buprenorphine concentrations. After a 4-week washout period, the same birds received the same formulation at a higher dose (1.8 mg/kg, SC), and blood samples were collected at 13 time points over 96 hours. Hawks were monitored for adverse effects and assigned agitation-sedation scores at each sample collection time. Plasma buprenorphine concentrations were quantified by liquid chromatography-tandem mass spectrometry. RESULTS Mean time to maximum plasma buprenorphine concentration was 7.2 minutes and 26.1 minutes after administration of the 0.3-mg/kg and 1.8-mg/kg doses, respectively. Plasma buprenorphine concentrations were > 1 ng/mL for mean durations of 24 and 48 hours after low- and high-dose administration, respectively. Mean elimination half-life was 6.23 hours for the low dose and 7.84 hours for the high dose. Mean agitation-sedation scores were higher (indicating some degree of sedation) than the baseline values for 24 hours at both doses. No clinically important adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Concentrated buprenorphine was rapidly absorbed, and plasma drug concentrations considered to have analgesic effects in other raptor species were maintained for extended periods. Most birds had mild to moderate sedation. Additional studies are needed to evaluate the pharmacodynamics of these doses of concentrated buprenorphine in red-tailed hawks.

Hawking into Unruh mapping for embeddings of hyperbolic type

International Nuclear Information System (INIS)

Paston, S A

2015-01-01

We study the conditions of the existence of Hawking into Unruh mapping for hyperbolic (Fronsdal-type) metric embeddings into the Minkowski space, for which timelines are hyperbolas. Many examples are known for global embeddings into the Minkowskian spacetime (GEMS), with such mapping for physically interesting metrics with some symmetry. However, examples of embeddings, both smooth and hyperbolic, for which there is no mapping, were also given. In the present work we prove that Hawking into Unruh mapping takes place for a hyperbolic embedding of an arbitrary metric with a time-like Killing vector and a Killing horizon if the embedding of such type exists and smoothly covers the horizon. At the same time, we do not assume any symmetry (spherical, for example), except the time translational invariance, which corresponds to the existence of a time-like Killing vector. We show that the known examples of the absence of mapping do not satisfy the formulated conditions of its existence. (paper)

''Splendeurs et miseres'' of Hawking's effect

Energy Technology Data Exchange (ETDEWEB)

Hijicek, P

1977-01-01

The Hawking effect, the result that a Schwarzschild black hole will emit particles as if it were a hot body with a given temperature depending upon the mass of the hole and the sun, the Planck, Newton, and Boltzmann constants, and the light velocity, is considered. Restriction is made to the Schwarzschild space-time, in order to suppress the geometrical, purely general relativistic aspects as far as possible. The treatment includes quantum field theory in curved space--times, and spherically symmetric collapse. 23 references. (JFP)

Remarks on Hawking radiation as tunneling from a uniformly ...

Indian Academy of Sciences (India)

Abstract. Motivated by the Hamilton–Jacobi method of Angheben et al, we investigate the Hawking tunneling radiation from a uniformly accelerating rectilinear black hole for which the horizons and entropy are functions of θ. After several coordinate transforma- tions, we conclude that when the self-gravitational interaction ...

Protective effects of Mengshan green tea and hawk tea against UV-ray irradiation

International Nuclear Information System (INIS)

Chen Xiaoming; Ren Zhenglong; Zhang Huaiyu; Tang Zongxiang; Luo Peigao

2005-01-01

A group of cultured normal human skin-derived fibroblasts was used as the cell model to investigate protective and repair effects of aqueous extracts of Mengshan green tea and Hawk tea against 320-400 nm UV-ray irradiation, with the methods of MTT colorimetry and LDH release. It was found that the aqueous extracts had strong protective effect on fibroblasts against the UV-rays with dose dependence. There were no significant differences between the two kinds of tea aqueous extracts in a higher concentration of 5 mg/mL, whereas at lower concentrations of 2.5 and 1.25 mg/mL the, green tea aqueous extract was less effective than the hawk-tea aqueous extract in protecting fibroblasts from the UV-ray damage. Meanwhile, it was discovered that the green tea and hawk-tea aqueous extract could repair damages induced by the UV irradiation with dose dependence. But there were no statistically significant differences between the two kinds of aqueous extract. The effects may be related to antioxidant effect of tea polyphenol. (authors)

The Superheavy Elements and Anti-Gravity

Science.gov (United States)

Anastasovski, Petar K.

2004-02-01

The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z Hawking, in honour of Stephen W. Hawking.

Tripping with Stephen Gaskin: An Exploration of a Hippy Adult Educator

Science.gov (United States)

Morley, Gabriel Patrick

2012-01-01

For the last 40 years, Stephen Gaskin has been an adult educator on the fringe, working with tens of thousands of adults in the counterculture movement in pursuit of social change regarding marijuana legalization, women's rights, environmental justice issues and beyond. Gaskin has written 11 books about his experiences teaching and learning…

A simple proof of the recent generalizations of Hawking's black hole topology theorem

Energy Technology Data Exchange (ETDEWEB)

Racz, Istvan [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)], E-mail: iracz@sunserv.kfki.hu

2008-08-21

A key result in four-dimensional black hole physics, since the early 1970s, is Hawking's topology theorem assertion that the cross-sections of an 'apparent horizon', separating the black hole region from the rest of the spacetime, are topologically 2-spheres. Later, during the 1990s, by applying a variant of Hawking's argument, Gibbons and Woolgar could also show the existence of a genus-dependent lower bound for the entropy of topological black holes with negative cosmological constant. Recently, Hawking's black hole topology theorem, along with the results of Gibbons and Woolgar, has been generalized to the case of black holes in higher dimensions. Our aim here is to give a simple self-contained proof of these generalizations, which also makes their range of applicability transparent. (fast track communication)

Property of various correlation measures of open Dirac system with Hawking effect in Schwarzschild space–time

International Nuclear Information System (INIS)

He, Juan; Xu, Shuai; Yu, Yang; Ye, Liu

2015-01-01

We explore the performance of various correlation measures for open Dirac system with Hawking effect in Schwarzschild space–time. Our results indicate that the impact of Hawking effect on physical accessible entanglement is weaker than that of decoherence. For generalized amplitude damping (GAD) channel, the entanglement sudden death (ESD) is analyzed in detail, and the inequivalence of quantization for Dirac particles in the black hole and Kruskal space–time is verified via quantum discord measure. In addition, as an example for interpreting Bell non-locality, we study the GAD channel with Hawking effect. It can be noticed that there is a boundary line of Bell violation for physically accessible states. That is, quantum non-locality would disappear when Hawking temperature exceeds a certain value. This critical temperature increases as a decoherence parameter decreases. In the case of phase damping (PD) channel, the interaction between the particle and noise environment does not produce bipartite system–environment entanglement. Then we discuss entanglement distributions, and find that the reduced physically accessible entanglement can be redistributed to physical inaccessible region. At last, we extend our investigation to an N-qubit system, and obtain a universal expression of the physical accessible entanglement

DPPH Radical Scavenging and Postprandial Hyperglycemia Inhibition Activities and Flavonoid Composition Analysis of Hawk Tea by UPLC-DAD and UPLC-Q/TOF MSE

Directory of Open Access Journals (Sweden)

Xuan Xiao

2017-10-01

Full Text Available Hawk tea (Litsea coreana Lévl. var. Lanuginosa (Migo Yen C. Yang & P.H. Huang, a very popular herbal tea material, has attracted more and more attention due to its high antioxidant properties and possible therapeutic effect on type II diabetes mellitus. The raw materials of Hawk tea are usually divided into three kinds: bud tea (BT, primary leaf tea (PLT and mature leaf tea (MLT. In this study, the DPPH radical scavenging activity and the antimicrobial properties of these three kinds of Hawk tea from different regions were comparatively investigated, and a ultra-high performance liquid chromatographic coupled with a photodiode array detector (UPLC-DAD method was employed for comparison of the three major flavonoid constituents, including hyperoside, isoquercitrin and astragalin, in different samples of Hawk tea. At the same time, the effect of methanol extract (ME of PLT on the mouse postprandial blood glucose and the effect of ME and its different fractions (petroleum ether fraction (PE, ethyl acetate fraction (EA, n-butanol fraction (n-BuOH, and water fraction (WF on the activity of α-glucosidase were studied. The results showed that Hawk BT and Hawk PLT possessed the higher radicals scavenging activity than Hawk MLT, while the antibacterial activity against P. vulgaris of PLT and MLT was higher than Hawk BT. The contents of the three major flavonoid constituents in samples of Hawk PLT are higher than Hawk BT and Hawk MLT. The mouse postprandial blood glucose levels of the middle dose (0.5 g/kg group and the high dose (1 g/kg group with oral administration of the ME of PLT were significantly lower than the control group. What’s more, the inhibitory effect of ME of PLT and its EA and n-BuOH fractions on α-glucosidase was significantly higher than that of acarbose. Rapid ultra-high performance liquid chromatography/quadrupole time-of-flight-mass spectrometry (UPLC-ESI-QTOF-MS was used to identify the flavonoids in Hawk PLT, and a total of

A life history approach to delineating how harsh environments and hawk temperament traits differentially shape children's problem-solving skills.

Science.gov (United States)

Suor, Jennifer H; Sturge-Apple, Melissa L; Davies, Patrick T; Cicchetti, Dante

2017-08-01

Harsh environments are known to predict deficits in children's cognitive abilities. Life history theory approaches challenge this interpretation, proposing stressed children's cognition becomes specialized to solve problems in fitness-enhancing ways. The goal of this study was to examine associations between early environmental harshness and children's problem-solving outcomes across tasks varying in ecological relevance. In addition, we utilize an evolutionary model of temperament toward further specifying whether hawk temperament traits moderate these associations. Two hundred and one mother-child dyads participated in a prospective multimethod study when children were 2 and 4 years old. At age 2, environmental harshness was assessed via maternal report of earned income and observations of maternal disengagement during a parent-child interaction task. Children's hawk temperament traits were assessed from a series of unfamiliar episodes. At age 4, children's reward-oriented and visual problem-solving were measured. Path analyses revealed early environmental harshness and children's hawk temperament traits predicted worse visual problem-solving. Results showed a significant two-way interaction between children's hawk temperament traits and environmental harshness on reward-oriented problem-solving. Simple slope analyses revealed the effect of environmental harshness on reward-oriented problem-solving was specific to children with higher levels of hawk traits. Results suggest early experiences of environmental harshness and child hawk temperament traits shape children's trajectories of problem-solving in an environment-fitting manner. © 2017 Association for Child and Adolescent Mental Health.

Suveräänsus kui organiseeritud silmakirjalikkus / Stephen Krasner ; interv. Erkki Bahovski

Index Scriptorium Estoniae

Krasner, Stephen

2007-01-01

USA poliitikateadlane räägib suveräänsuse mõistest Euroopa Liidu ja Eesti-Vene suhete näiteil, külma sõja puhkemise võimalusest, maailma riikide poliitikast ja ÜRO reformimisest. Lisa: Krasner, Stephen. Vt. samas: Paindlik suveräänsus

God's Turnstile: The Work of John Wheeler and Stephen Hawking.

Science.gov (United States)

Overbye, Dennis

1991-01-01

Presents an excerpt from the book entitled "Lonely Hearts of the Cosmos." Provides narration of behind-the-scenes events in the lives, the scientific debates, and the intellectual triumphs of the two physicists responsible for inventing the concept of the black hole. (JJK)

GRIP NOAA GLOBAL HAWK IN-FLIGHT TURBULENCE SENSOR (GHIS) V1

Data.gov (United States)

National Aeronautics and Space Administration — The NOAA Global Hawk In-flight Turbulence Sensor (GHIS) instrument measures acceleration at the location of the instrument. Two accelerometers (2g and 5g full scale)...

Astronaut Stephen Oswald and fellow crew members on middeck

Science.gov (United States)

1995-01-01

Astronaut Stephen S. Oswald (center), STS-67 mission commander, is seen with two of his fellow crew members and an experiment which required a great deal of his time on the middeck of the Earth orbiting Space Shuttle Endeavour. Astronaut John M. Grunsfeld inputs mission data on a computer while listening to a cassette. Astronaut William G. Gregory (right edge of frame), pilot, consults a check list. The Middeck Active Control Experiment (MACE), not in use here, can be seen in upper center.

String theorist takes over as Lucasian Professor

Science.gov (United States)

Banks, Michael

2009-11-01

String theorist Michael Green will be the next Lucasian Professor of Mathematics at Cambridge University. Green, 63, will succeed Stephen Hawking, who held the chair from 1980 before retiring last month at the age of 67 and taking up a distinguished research chair at the Perimeter Institute for Theoretical Physics in Canada (see above).

Integral method for the calculation of Hawking radiation in dispersive media. II. Asymmetric asymptotics.

Science.gov (United States)

Robertson, Scott

2014-11-01

Analog gravity experiments make feasible the realization of black hole space-times in a laboratory setting and the observational verification of Hawking radiation. Since such analog systems are typically dominated by dispersion, efficient techniques for calculating the predicted Hawking spectrum in the presence of strong dispersion are required. In the preceding paper, an integral method in Fourier space is proposed for stationary 1+1-dimensional backgrounds which are asymptotically symmetric. Here, this method is generalized to backgrounds which are different in the asymptotic regions to the left and right of the scattering region.

Pharmacokinetics of a single dose of voriconazole administered orally with and without food to red-tailed hawks (Buteo jamaicensus)

NARCIS (Netherlands)

Parsley, Ruth A; Tell, Lisa A; Gehring, Ronette

OBJECTIVE To determine the pharmacokinetics of voriconazole administered PO with or without food to red-tailed hawks (Buteo jamaicensus) and whether any observed variability could be explained by measured covariates to inform dose adjustments. ANIMALS 7 adult red-tailed hawks. PROCEDURES In a

Hawking Radiations from an Arbitrarily Accelerating Kerr Black Hole ...

Indian Academy of Sciences (India)

Introduction. In 1976, Damour & Ruffini (1976) presented a method proving Hawking radiation. Zhao et al. (1994) improved the method of Damour and Ruffini, and calculated the location of the event horizon and the temperature of the varying black holes at the same time. It is a pivotal step to introduce a tortoise coordinate ...

The Hawk-Dove game in phenotypically homogeneous and heterogeneous populations of finite dimension

Science.gov (United States)

Laruelle, Annick; da Silva Rocha, André Barreira; Escobedo, Ramón

2018-02-01

The Hawk-Dove game played between individuals in populations of finite dimension is analyzed by means of a stochastic model. We take into account both cases when all individuals in the population are either phenotypically homogeneous or heterogeneous. A strategy in the model is a gene representing the probability of playing the Hawk strategy. Individual interactions at the microscopic level are described by a genetic algorithm where evolution results from the interplay among selection, mutation, drift and cross-over of genes. We show that the behavioral patterns observed at the macroscopic level can be reproduced as the emergent result of individual interactions governed by the rules of the Hawk-Dove game at the microscopic level. We study how the results of the genetic algorithm compare with those obtained in evolutionary game theory, finding that, although genes continuously change both their presence and frequency in the population over time, the population average behavior always achieves stationarity and, when this happens, the final average strategy played in the population oscillates around the evolutionarily stable strategy in the homogeneous population case or the neutrally stable set in the heterogeneous population case.

Post-religional perspective and secular Buddhism: Stephen Batchelor and the post-metaphysical religion

Directory of Open Access Journals (Sweden)

Leandro Durazzo

2015-04-01

Full Text Available This paper aims to present one of the contemporary trends on Buddhism, specially from the last decades in West, for its encounter with the globalized and dynamic context of present societies. This Buddhist trend, the progressive secularization of its traditions and practices, not to mention its increasing acceptance of historical-textual refutation, finds in Stephen Batchelor - a former monk in two different Buddhist traditions, Tibetan and Korean Zen - a catalyzer and a well-known advocate of secular perspective to the contemporary Buddhism. Here we will present the potential dialogue between the Secular Buddhism - besides the secularizing perspectives over orthodox cultural traditions - and the post-religional subject, as proposed by Marià Corbí and the Ecumenical Association of Third World Theologians. For the purposes of this paper we will focus on the modernizing and secular hermeneutics on Dharma practice, as defended by Stephen Batchelor and others.

Thermal hadron production by QCD Hawking radiation

International Nuclear Information System (INIS)

Satz, Helmut

2007-01-01

The QCD counterpart of Hawking radiation from black holes leads to thermal hadron production in high energy collisions, from e + e - annihilation to heavy ion interactions. This hadronic radiation is emitted at a universal temperature T≅(σ/2π) 1/2 , where the string tension σ measures the colour field at the event horizon of confinement. Moreover, the emitted radiation is thermal 'at birth'; since the event horizon prevents all information transfer, no memory has to be destroyed kinetically. (author)

Effect of the refractive index on the hawking temperature: an application of the Hamilton-Jacobi method

Science.gov (United States)

Sakalli, I.; Mirekhtiary, S. F.

2013-10-01

Hawking radiation of a non-asymptotically flat 4-dimensional spherically symmetric and static dilatonic black hole (BH) via the Hamilton-Jacobi (HJ) method is studied. In addition to the naive coordinates, we use four more different coordinate systems that are well-behaved at the horizon. Except for the isotropic coordinates, direct computation by the HJ method leads to the standard Hawking temperature for all coordinate systems. The isotropic coordinates allow extracting the index of refraction from the Fermat metric. It is explicitly shown that the index of refraction determines the value of the tunneling rate and its natural consequence, the Hawking temperature. The isotropic coordinates in the conventional HJ method produce a wrong result for the temperature of the linear dilaton. Here, we explain how this discrepancy can be resolved by regularizing the integral possessing a pole at the horizon.

Effect of the refractive index on the hawking temperature: an application of the Hamilton-Jacobi method

Energy Technology Data Exchange (ETDEWEB)

Sakalli, I., E-mail: izzet.sakalli@emu.edu.tr; Mirekhtiary, S. F., E-mail: fatemeh.mirekhtiary@emu.edu.tr [Eastern Mediterranean University G. Magosa, Department of Physics (Turkey)

2013-10-15

Hawking radiation of a non-asymptotically flat 4-dimensional spherically symmetric and static dilatonic black hole (BH) via the Hamilton-Jacobi (HJ) method is studied. In addition to the naive coordinates, we use four more different coordinate systems that are well-behaved at the horizon. Except for the isotropic coordinates, direct computation by the HJ method leads to the standard Hawking temperature for all coordinate systems. The isotropic coordinates allow extracting the index of refraction from the Fermat metric. It is explicitly shown that the index of refraction determines the value of the tunneling rate and its natural consequence, the Hawking temperature. The isotropic coordinates in the conventional HJ method produce a wrong result for the temperature of the linear dilaton. Here, we explain how this discrepancy can be resolved by regularizing the integral possessing a pole at the horizon.

Covariant anomalies and Hawking radiation from charged rotating black strings in anti-de Sitter spacetimes

International Nuclear Information System (INIS)

Peng Junjin; Wu Shuangqing

2008-01-01

Motivated by the success of the recently proposed method of anomaly cancellation to derive Hawking fluxes from black hole horizons of spacetimes in various dimensions, we have further extended the covariant anomaly cancellation method shortly simplified by Banerjee and Kulkarni to explore the Hawking radiation of the (3+1)-dimensional charged rotating black strings and their higher dimensional extensions in anti-de Sitter spacetimes, whose horizons are not spherical but can be toroidal, cylindrical or planar, according to their global identifications. It should be emphasized that our analysis presented here is very general in the sense that the determinant of the reduced (1+1)-dimensional effective metric from these black strings need not be equal to one (√(-g)≠1). Our results indicate that the gauge and energy-momentum fluxes needed to cancel the (1+1)-dimensional covariant gauge and gravitational anomalies are compatible with the Hawking fluxes. Besides, thermodynamics of these black strings are studied in the case of a variable cosmological constant

Contrast fluoroscopic evaluation of gastrointestinal transit times with and without the use of falconry hoods in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Doss, Grayson A; Williams, Jackie M; Mans, Christoph

2017-11-01

OBJECTIVE To evaluate gastrointestinal transit times in red-tailed hawks (Buteo jamaicensis) by use of contrast fluoroscopic imaging and investigate the effect of falconry hooding in these hawks on gastrointestinal transit time. DESIGN Prospective, randomized, blinded, complete crossover study. ANIMALS 9 healthy red-tailed hawks. PROCEDURES Hawks were gavage-fed a 30% weight-by-volume barium suspension (25 mL/kg [11.3 mL/lb]) into the crop. Fluoroscopic images were obtained at multiple time points after barium administration. Time to filling and emptying of various gastrointestinal tract organs and overall transit time were measured. The effect of hooding (hooded vs nonhooded) on these variables was assessed in a randomized complete crossover design. RESULTS In nonhooded birds, overall gastrointestinal transit time ranged from 30 to 180 minutes (mean ± SD, 100 ± 52 min). Time to complete crop emptying ranged from 30 to 180 minutes (83 ± 49 min). Contrast medium was present in the ventriculus in all birds within 5 minutes of administration and in the small intestines within 5 to 15 minutes (median, 5 min). Hooding of red-tailed hawks resulted in a significant delay of complete crop emptying (no hood, 83 ± 49 minutes; hood, 133 ± 48 minutes), but no significant effects of hooding were found on other measured variables. CONCLUSIONS AND CLINICAL RELEVANCE These results indicated that overall gastrointestinal transit times are faster in red-tailed hawks than has been reported for psittacines and that the use of a falconry hood in red-tailed hawks may result in delayed crop emptying. Hooding did not exert significant effects on overall gastrointestinal transit time in this raptorial species.

Power/Knowledge for Educational Theory: Stephen Ball and the Reception of Foucault

Science.gov (United States)

Wang, Chia-Ling

2011-01-01

This paper explores the significance of the concept of power/knowledge in educational theory. The argument proceeds in two main parts. In the first, I consider aspects of Stephen J. Ball's highly influential work in educational theory. I examine his reception of Foucault's concept of power/knowledge and suggest that there are problems in his…

A no-man's-land of sex: Reading Stephen Gordon and "her" critics.

Science.gov (United States)

Costello, Katherine A

2018-04-03

One of the most read novels of lesbian, transgender, and queer criticism, Radclyffe Hall's novel The Well of Loneliness (1928) has given rise to numerous and contradictory interpretations of the protagonist Stephen Gordon's complex relationship to her body. Some have argued that she is a historically specific example of female masculinity, others that she is a lesbian who wishes she were more feminine, and others still that she is a prototypical transsexual character. Focusing on the exemplary essays by Jack Halberstam, Teresa de Lauretis, and Jay Prosser, I argue that the coexistence of mutually exclusive interpretations of Stephen Gordon's relationship to her femaleness suggests that the novel is, in fact, a demand to readers to unmoor identity from sex and to recognize what I call "sexual indeterminacy." Lesbian, transgender, and queer theory's tendency to elide the literariness of literary objects and their reliance on critique as the primary mode of reading and argumentation have made it impossible for critics to see that the novel is explicitly about what cannot be settled.

Hawking radiation and strong gravity black holes

International Nuclear Information System (INIS)

Qadir, A.; Sayed, W.A.

1979-01-01

It is shown that the strong gravity theory of Salam et al. places severe restrictions on black hole evaporation. Two major implications are that: mini blck holes (down to masses approximately 10 -16 kg) would be stable in the present epoch; and that some suggested mini black hole mechanisms to explain astrophysical phenomena would not work. The first result implies that f-gravity appears to make black holes much safer by removing the possibility of extremely violent black hole explosions suggested by Hawking. (Auth.)

High frequency of extra-pair paternity in an urban population of Cooper's Hawks

Science.gov (United States)

Rosenfield, Robert N.; Sonsthagen, Sarah A.; Stout, William C.; Talbot, Sandra L.

2015-01-01

Raptors exhibit some of the highest rates of intra-pair copulations among birds, perhaps in an attempt by males to reduce the risk of being cuckolded. Indeed, the frequency of extra-pair fertilizations reported in studies of raptors to date is relatively low (0-11.2%). Socially monogamous Cooper's Hawks (Accipiter cooperii) exhibit one of the highest copulation rates among birds, yet there are no published accounts of extra-pair copulations (or paternity). We studied a population of Cooper's Hawks in Milwaukee, Wisconsin, during three breeding seasons (2003, 2004, and 2007), examining the possible effects of age (1 yr old vs. ≥ 2 yr old), adult mass, and brood size on the frequency of extra-pair paternity (EPP). We found that 19.3% of nestlings (N = 27/140) were extra-pair young (EPY), and 34% of all broods (N = 15/44) had at least one EPY. The sires of the EPY in our study were identified for only two broods, suggesting that floater males may have engaged in extra-pair copulations with territorial females. We found that brood size was a good predictor of the occurrence of EPP (EPP) in nests, but adult mass and female age were not. To our knowledge, these possible correlates of the occurrence of EPP in raptors had not previously been investigated. Male Cooper's Hawks provide food for females during the pre-nesting period, and delivery of food is, in contrast to other raptor species, typically followed by copulation. Thus, one possible explanation of the relatively high rates of EPP in our study is that females might accept or even solicit extra-pair copulations from males other than their mates as a means of maximizing energy intake for egg production. Such behavior might be particularly likely in our study area, i.e., a food-rich urban setting with a high breeding density of Cooper's Hawks.

INFLAMMATORY MARKERS ASSOCIATED WITH TRAUMA AND INFECTION IN RED-TAILED HAWKS (BUTEO JAMAICENSIS) IN THE USA.

Science.gov (United States)

Lee, Kelly A; Goetting, Valerie S; Tell, Lisa A

2015-10-01

Changes in inflammatory marker concentrations or activity can be used to monitor health and disease condition of domestic animals but have not been applied with the same frequency to wildlife. We measured concentrations or activity of six inflammatory markers (ceruloplasmin, haptoglobin, mannan-binding lectin-dependent complement [MBL/complement], unsaturated iron-binding capacity (UIBC) and total iron-binding capacity (TIBC), and plasma iron) in apparently healthy and sick or injured Red-tailed Hawks (Buteo jamaicensis). Haptoglobin and ceruloplasmin activities were consistently elevated in sick or injured hawks (2.1 and 2.5 times higher, respectively), and plasma iron concentrations decreased (0.46 times lower), relative to those of healthy birds. There were no differences between healthy and unhealthy hawks in TIBC and UIBC concentrations or MBL/complement activity. Therefore, haptoglobin, ceruloplasmin, and plasma iron would be useful inclusions in a panel of inflammatory markers for monitoring health in raptors.

Effect of West Nile virus DNA-plasmid vaccination on response to live virus challenge in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Redig, Patrick T; Tully, Thomas N; Ritchie, Branson W; Roy, Alma F; Baudena, M Alexandra; Chang, Gwong-Jen J

2011-08-01

To evaluate the safety and efficacy of an experimental adjuvanted DNA-plasmid vaccine against West Nile virus (WNV) in red-tailed hawks (Buteo jamaicensis). 19 permanently disabled but otherwise healthy red-tailed hawks of mixed ages and both sexes without detectable serum antibodies against WNV. Hawks were injected IM with an experimental WNV DNA-plasmid vaccine in an aluminum-phosphate adjuvant (n = 14) or with the adjuvant only (control group; 5). All birds received 2 injections at a 3-week interval. Blood samples for serologic evaluation were collected before the first injection and 4 weeks after the second injection (day 0). At day 0, hawks were injected SC with live WNV. Pre- and postchallenge blood samples were collected at intervals for 14 days for assessment of viremia and antibody determination; oropharyngeal and cloacal swabs were collected for assessment of viral shedding. Vaccination was not associated with morbidity or deaths. Three of the vaccinated birds seroconverted after the second vaccine injection; all other birds seroconverted following the live virus injection. Vaccinated birds had significantly less severe viremia and shorter and less-intense shedding periods, compared with the control birds. Use of the WNV DNA-plasmid vaccine in red-tailed hawks was safe, and vaccination attenuated but did not eliminate both the viremia and the intensity of postchallenge shedding following live virus exposure. Further research is warranted to conclusively determine the efficacy of this vaccine preparation for protection of red-tailed hawks and other avian species against WNV-induced disease.

PRS and POS/PRS coupling experiments on Hawk

Energy Technology Data Exchange (ETDEWEB)

Peterson, G G; Apruzese, J P; Commisso, R J [Naval Research Laboratory, Washington, DC (United States). Plasma Physics Div.; and others

1997-12-31

Experiments are being conducted on Hawk to investigate the electrical coupling of a plasma opening switch (POS) to a neon plasma radiation source (PRS) and to evaluate the K SHELL x-ray yield scaling of implosions with different initial radii, mass, and implosion times. Understanding the coupling and scaling is important for optimizing the performance of more powerful inductive-storage generators that rely on POS technology. (author). 1 tab., 5 figs., 7 refs.

Distribution and geographical variation of the White-tailed Hawk (Buteo albicaudatus)

NARCIS (Netherlands)

Voous, K.H.

1968-01-01

The present knowledge on infraspecific variation, distribution, and migration of the White-tailed Hawk ( Buteo albicaudatus Vieillot) is critically reviewed. In practically every aspect knowledge is highly inadequate. Size variation (tables I—IV) is in accordance with Bergmann’s Phenomenon, but does

Plumage polymorphism and fitness in Swainson's hawks.

Science.gov (United States)

Briggs, C W; Collopy, M W; Woodbridge, B

2011-10-01

We examine the maintenance of a plumage polymorphism, variation in plumages among the same age and sex class within a population, in a population of Swainson's Hawks. We take advantage of 32 years of data to examine two prevalent hypotheses used to explain the persistence of morphs: apostatic selection and heterozygous advantage. We investigate differences in fitness among three morph classes of a melanistic trait in Swainson's Hawks: light (7% of the local breeding population), intermediate (57%) and dark (36%). Specifically, we examined morph differences in adult apparent survival, breeding success, annual number of fledglings produced, probability of offspring recruitment into the breeding population and lifetime reproductive success (LRS). If apostatic selection were a factor in maintaining morphs, we would expect that individuals with the least frequent morph would perform best in one or more of these fitness categories. Alternatively, if heterozygous advantage played a role in the maintenance of this polymorphism, we would expect heterozygotes (i.e. intermediate morphs) to have one or more increased rates in these categories. We found no difference in adult apparent survival between morph classes. Similarly, there were no differences in breeding success, nest productivity, LRS or probability of recruitment of offspring between parental morph. We conclude that neither apostatic selection nor heterozygous advantage appear to play a role in maintaining morphs in this population. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Petrology, Palynology, and Geochemistry of Gray Hawk Coal (Early Pennsylvanian, Langsettian in Eastern Kentucky, USA

Directory of Open Access Journals (Sweden)

James C. Hower

2015-09-01

Full Text Available This study presents recently collected data examining the organic petrology, palynology, mineralogy and geochemistry of the Gray Hawk coal bed. From the Early Pennsylvanian, Langsettian substage, Gray Hawk coal has been mined near the western edge of the eastern Kentucky portion of the Central Appalachian coalfield. While the coal is thin, rarely more than 0.5-m thick, it has a low-ash yield and a low-S content, making it an important local resource. The Gray Hawk coal palynology is dominated by Lycospora spp., and contains a diverse spectrum of small lycopods, tree ferns, small ferns, calamites, and gymnosperms. The maceral assemblages show an abundance of collotelinite, telinite, vitrodetrinite, fusinite, and semifusinite. Fecal pellet-derived macrinite, albeit with more compaction than is typically seen in younger coals, was observed in the Gray Hawk coal. The minerals in the coal are dominated by clay minerals (e.g., kaolinite, mixed-layer illite/smectite, illite, and to a lesser extent, pyrite, quartz, and iron III hydroxyl-sulfate, along with traces of chlorite, and in some cases, jarosite, szomolnokite, anatase, and calcite. The clay minerals are of authigenic and detrital origins. The occurrence of anatase as cell-fillings also indicates an authigenic origin. With the exception of Ge and As, which are slightly enriched in the coals, the concentrations of other trace elements are either close to or much lower than the averages for world hard coals. Arsenic and Hg are also enriched in the top bench of the coal and probably occur in pyrite. The elemental associations (e.g., Al2O3/TiO2, Cr/Th-Sc/Th indicate a sediment-source region with intermediate and felsic compositions. Rare metals, including Ga, rare earth elements and Ge, are highly enriched in the coal ashes, and the Gray Hawk coals have a great potential for industrial use of these metals. The rare earth elements in the samples are weakly fractionated or are characterized by heavy

Microelectronic Status Analysis and Secondary Part Procureability Assessment of the HAWK Weapon System

National Research Council Canada - National Science Library

Maddux, Gary

2000-01-01

The MT Division, Engineering Directorate (ED), RDEC, AMCOM has the mission and function of providing microelectronic technology assessments, and producibility and supportability analyses for the HAWK weapon system...

Microelectronic Status Analysis and Secondary Part Procureability Assessment of the HAWK Weapon System

National Research Council Canada - National Science Library

Maddux, Gary

1999-01-01

The Industrial Operations Division (IOD), SEPD, RDEC, AMCOM has the mission and function of providing microelectronic technology assessments, and producibility and supportability analyses for the HAWK weapon system...

Hawk eyes II: diurnal raptors differ in head movement strategies when scanning from perches.

Science.gov (United States)

O'Rourke, Colleen T; Pitlik, Todd; Hoover, Melissa; Fernández-Juricic, Esteban

2010-09-22

Relatively little is known about the degree of inter-specific variability in visual scanning strategies in species with laterally placed eyes (e.g., birds). This is relevant because many species detect prey while perching; therefore, head movement behavior may be an indicator of prey detection rate, a central parameter in foraging models. We studied head movement strategies in three diurnal raptors belonging to the Accipitridae and Falconidae families. We used behavioral recording of individuals under field and captive conditions to calculate the rate of two types of head movements and the interval between consecutive head movements. Cooper's Hawks had the highest rate of regular head movements, which can facilitate tracking prey items in the visually cluttered environment they inhabit (e.g., forested habitats). On the other hand, Red-tailed Hawks showed long intervals between consecutive head movements, which is consistent with prey searching in less visually obstructed environments (e.g., open habitats) and with detecting prey movement from a distance with their central foveae. Finally, American Kestrels have the highest rates of translational head movements (vertical or frontal displacements of the head keeping the bill in the same direction), which have been associated with depth perception through motion parallax. Higher translational head movement rates may be a strategy to compensate for the reduced degree of eye movement of this species. Cooper's Hawks, Red-tailed Hawks, and American Kestrels use both regular and translational head movements, but to different extents. We conclude that these diurnal raptors have species-specific strategies to gather visual information while perching. These strategies may optimize prey search and detection with different visual systems in habitat types with different degrees of visual obstruction.

Spherical domain wall formed by field dynamics of Hawking radiation and spontaneous charging-up of black hole

International Nuclear Information System (INIS)

Nagatani, Yukinori

2004-01-01

We investigate the Hawking radiation in the gauge Higgs-Yukawa theory. The ballistic model is proposed as an effective description of the system. We find that a spherical domain wall around the black hole is formed by field dynamics rather than thermal phase transition. The formation is a general property of the black hole whose Hawking temperature is equal to or greater than the energy scale of the theory. The formation of the electroweak wall and that of the GUT wall are shown. We also find a phenomenon of the spontaneous charging-up of the black hole by the wall. The Hawking radiation drives a mechanism of the charge transportation into the black hole when C- and CP-violation are assumed. The mechanism can strongly transport the hyper-charge into a black hole of the electroweak scale

Oceanic Weather Decision Support for Unmanned Global Hawk Science Missions into Hurricanes with Tailored Satellite Derived Products

Science.gov (United States)

Feltz, Wayne; Griffin, Sarah; Velden, Christopher; Zipser, Ed; Cecil, Daniel; Braun, Scott

2017-04-01

The purpose of this presentation is to identify in-flight hazards to high-altitude aircraft, namely the Global Hawk. The Global Hawk was used during Septembers 2012-2016 as part of two NASA funded Hurricane Sentinel-3 field campaigns to over-fly hurricanes in the Atlantic Ocean. This talk identifies the cause of severe turbulence experienced over Hurricane Emily (2005) and how a combination of NOAA funded GOES-R algorithm derived cloud top heights/tropical overshooting tops using GOES-13/SEVIRI imager radiances, and lightning information are used to identify areas of potential turbulence for near real-time navigation decision support. Several examples will demonstrate how the Global Hawk pilots remotely received and used real-time satellite derived cloud and lightning detection information to keep the aircraft safely above clouds and avoid regions of potential turbulence.

Response to Professor Stephen Jenkins’ comments on the World Income Inequality Database (WIID)

DEFF Research Database (Denmark)

Badgaiyan, Nina; Pirttilä, Jukka; Tarp, Finn

2015-01-01

Professor Stephen Jenkins (this issue) has conducted an extremely careful and insightful analysis of two datasets, WIID and SWIID. In this short response, we focus on his review of the WIID, maintained and published by UNU-WIDER in agreement with the World Bank. We wish to highlight at the outset...

Breeding biology and conservation of hawk-eagles (Spizaetus spp. (Aves, Accipitridae in southern Atlantic Forest, Brazil

Directory of Open Access Journals (Sweden)

Felipe Zilio

2017-10-01

Full Text Available ABSTRACT Neotropical hawk-eagles (Spizaetus spp. are large forest raptors, having low population densities and high sensitivity to human disturbance. The three species of Brazil’s Atlantic forest (S. ornatus, S. melanoleucus, S. tyrannus are threatened and little is known of many aspects of their biology, such habitat requirements, nesting behavior, and food habitats. Here I present data about the breeding biology, diet and behavior of the Ornate Hawk-Eagle (S. ornatus; OHE and the Black-and-white Hawk-Eagle (S. melanoleucus; BWHW, and estimations of distribution - extent of occurrence (EOO - and population sizes for the three hawk-eagles of the southern Atlantic Forest. I compiled data from nine years of field studies done in Rio Grande do Sul and Santa Catarina combined with data from the literature (n = 191 records. I calculated the total amount of forest available for each species by GIS analyses and estimated population sizes based on species density data from the literature. The EOO was 123,551 km² for BWHE, 92,512 km² for OHE, and 67,824 km² for Black Hawk-Eagle (S. tyrannus; BHE. All species experienced more than 30% shrinkage in their historical distribution (before the year 2000. Forest remnants comprise 32% of BHE’s EOO and around 20% for other hawk-eagle species. Population sizes estimated for the southern region were 869 pairs for BHE (1,684 individuals, 1,532 pairs for BWHE (2,849 individuals, and 2,020 pairs for OHE (1,192 individuals. Population size estimates based only on forest patches larger than 10 km² were 542 pairs for BHE (RS = 48 pairs; SC = 494 pairs, 818 pairs for BWHE (RS = 67 pairs; SC = 751 pairs, and 1,178 pairs for OHE (RS = 67 pairs; SC = 1,111 pairs. I recorded displays and copulation of BWHE in July; the nest was built in an inaccessible, emergent tree in the hillside of a valley. Two nests of OHE were found in emergent trees (20 m and 30 m height measured 138 x 115 x 45 cm and 132 x 100 x 100 cm; one

Fulltext PDF

Indian Academy of Sciences (India)

ART

Penrose and Stephen Hawking to tackle the issue of singularity of the Big Bang. It is a symptom of the malaise of Indian science that Raychaudhuri was recognized late in life. It was because he did not covet the life of an award-studded scientist and chose to teach in a college in Kolkata. He taught at the Presidency College ...

Preliminary clinical application of SilverHawk directional atherectomy device in arteriosclerosis obliterans of lower extremity

International Nuclear Information System (INIS)

Qian Jun; Jiang Hong; Xu Gang; Yang Xiaohong

2011-01-01

Objective: To evaluate the clinical efficiency and security of SilverHawk directional atherectomy device in treating arteriosclerosis obliterans of lower extremity. Methods: Seven patients with lower extremity ischemia were treated with SilverHawk directional atherectomy. The lesions length varied from 1.8 to 14.5 cm. Clinical symptoms (Fontaine classification) included 4 cases of grade Ⅱ b, I case of grade Ⅲ, 2 cases of grade Ⅳ. The ABI varied from 0.28 to 0.65. Patency was evaluated with color duplex sonography or CTA besides clinical examination during follow-up. Results: Seven occlusive lesions were recanalizated successfully. The technical success (residual stenosis < 30%) rate was 100%. Clinical symptoms were obviously improved or disappeared. The ABI varied from 0.82 to 1.18 (P=0.002), and Fontaine classification included 6 cases of Ⅰ; 1 case of Ⅱ a. Patency rate was 100% and the ABI varied from 0.75 to 1.14 (P=0.938). Fontaine classifications keep consistent 1-6 months after operation. Conclusion: SilverHawk directional atherectomy was a safe and effective way for treatment of lower arteriosclerosis obliteran. (authors)

Genetic and morphological divergence among Cooper's Hawk (Accipiter cooperii) populations breeding in north-central and western North America

Science.gov (United States)

Sonsthagen, Sarah A.; Rosenfield, Robert N.; Bielefeldt, John; Murphy, Robert K.; Stewart, Andrew C.; Stout, William C.; Driscoll, Timothy G.; Bozek, Michael A.; Sloss, Brian L.; Talbot, Sandra L.

2012-01-01

Cooper's Hawk (Accipiter cooperii) populations breeding in the northern portion of the species' range exhibit variation in morphological traits that conforms to predictions based on differences in prey size, tree stand density, and migratory behavior. We examined genetic structure and gene flow and compared divergence at morphological traits (PST) and genetic markers (FST) to elucidate mechanisms (selection or genetic drift) that promote morphological diversification among Cooper's Hawk populations. Cooper's Hawks appear to conform to the genetic pattern of an east-west divide. Populations in British Columbia are genetically differentiated from north-central populations (Wisconsin, Minnesota, and North Dakota; pairwise microsatellite FST= 0.031-0.050; mitochondrial DNA ΦST = 0.177-0.204), which suggests that Cooper's Hawks were restricted to at least two Pleistocene glacial refugia. The strength of the Rocky Mountains—Great Plains area as a barrier to dispersal is further supported by restricted gene-flow rates between British Columbia and other sampled breeding populations. Divergence in morphological traits (PST) was also observed across study areas, but with British Columbia and North Dakota differentiated from Wisconsin and Minnesota, a pattern not predicted on the basis of FST and ΦST interpopulation estimates. Comparison of PSTand FSTestimates suggests that heterogeneous selection may be acting on Cooper's Hawks in the northern portion of their distribution, which is consistent with hypotheses that variation in prey mass and migratory behavior among populations may be influencing overall body size and wing chord. We were unable to distinguish between the effects of genetic drift and selection on tail length in the study populations.

A self-consistency check for unitary propagation of Hawking quanta

Science.gov (United States)

Baker, Daniel; Kodwani, Darsh; Pen, Ue-Li; Yang, I.-Sheng

2017-11-01

The black hole information paradox presumes that quantum field theory in curved space-time can provide unitary propagation from a near-horizon mode to an asymptotic Hawking quantum. Instead of invoking conjectural quantum-gravity effects to modify such an assumption, we propose a self-consistency check. We establish an analogy to Feynman’s analysis of a double-slit experiment. Feynman showed that unitary propagation of the interfering particles, namely ignoring the entanglement with the double-slit, becomes an arbitrarily reliable assumption when the screen upon which the interference pattern is projected is infinitely far away. We argue for an analogous self-consistency check for quantum field theory in curved space-time. We apply it to the propagation of Hawking quanta and test whether ignoring the entanglement with the geometry also becomes arbitrarily reliable in the limit of a large black hole. We present curious results to suggest a negative answer, and we discuss how this loss of naive unitarity in QFT might be related to a solution of the paradox based on the soft-hair-memory effect.

BEHAVIOR AND PREY OF NESTING RED-SHOULDERED HAWKS IN SOUTHWESTERN OHIO

Science.gov (United States)

We used direct observations to quantify prey types, prey delivery rate, and adult and nestling behavior at nests of Red-shouldered Hawks (Buteo lineatus) in suburban southwestern Ohio. Twenty-one nests were observed for a total of 256 hr in 1997-2001. Small mammals made up the ...

Ratio of critical quantities related to Hawking temperature–entanglement entropy criticality

Directory of Open Access Journals (Sweden)

Jie-Xiong Mo

2017-10-01

Full Text Available We revisit the Hawking temperature–entanglement entropy criticality of the d-dimensional charged AdS black hole with our attention concentrated on the ratio TcδSEcQc. Comparing the results of this paper with those of the ratio TcScQc, one can find both the similarities and differences. These two ratios are independent of the characteristic length scale l and dependent on the dimension d. These similarities further enhance the relation between the entanglement entropy and the Bekenstein–Hawking entropy. However, the ratio TcδSEcQc also relies on the size of the spherical entangling region. Moreover, these two ratios take different values even under the same choices of parameters. The differences between these two ratios can be attributed to the peculiar property of the entanglement entropy since the research in this paper is far from the regime where the behavior of the entanglement entropy is dominated by the thermal entropy.

Cassin\\'s hawk-eagle Spizaetus africanus in Ndundulu Forest: a first ...

African Journals Online (AJOL)

A single adult Cassin's hawk-eagle Spizaetus africanus was sighted on five occasions over three years in a highland forest in the Udzungwa Mountains, the first ever record of this species in Tanzania. This discovery has potentially significant biogeographical implications, strengthening ancient links between the forests of ...

Comentários sobre Columbus runs aground: Christmas Eve, 1942 (Stephen Greenblatt

Directory of Open Access Journals (Sweden)

Ilana Blaj

1991-07-01

Full Text Available (Primeiro Parágrafo do Artigo O texto do Prof. Stephen Greenblatt, por ser extremamente rico e denso, nos coloca uma série de questões para a reflexão. Selecionarei aqui alguns pontos de ordem teórico-metodológica e outros que se referem à análise histórica propriamente dita para começarmos o debate.

The STS-95 crew and their families prepare for their return flight to JSC

Science.gov (United States)

1998-01-01

At the Skid Strip at Cape Canaveral Air Station, STS-95 Pilot Steven W. Lindsey (left), Lindsey's daughter (front), and Payload Specialist John H. Glenn Jr. (right), a senator from Ohio and one of the original seven Project Mercury astronauts, give a thumbs up on the success of the mission. Members of the STS-95 crew and their families prepared for their return flight to the Johnson Space Center in Houston, Texas. The STS-95 mission ended with landing at Kennedy Space Center's Shuttle Landing Facility at 12:04 p.m. EST on Nov. 7. Others returning were Mission Commander Curtis L. Brown Jr.; Mission Specialist Scott E. Parazynski; Mission Specialist Stephen K. Robinson; Mission Specialist Pedro Duque, with the European Space Agency (ESA); and Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA). The mission included research payloads such as the Spartan-201 solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as a SPACEHAB single module with experiments on space flight and the aging process.

Science and the Humanities: Stephen Jay Gould's Quest to Join the High Table

Science.gov (United States)

Ruse, Michael

2013-01-01

Stephen Jay Gould was a scientist, a paleobiologist, who was also a professional-level historian of science. This essay explores Gould's work, showing how he used the history of science to further his agenda as a working scientist.

Quantum production of particles (the Hawking effect) in nonstationary black holes

International Nuclear Information System (INIS)

Volovich, I.V.; Zagrebnov, V.A.; Frolov, V.P.; AN SSSR, Moscow. Fizicheskij Inst.)

1976-01-01

Particle production in a gravitational field of a black hole with changing mass is considered. It is shown that in the case when parameters are changed adiabatically taking into account the nonstationarity is reduced effectively to the taking into account the dependence of the Hawking radiation temperature on the retarded time

Quantum production of particles (the Hawking effect) in nonstationary black holes

Energy Technology Data Exchange (ETDEWEB)

Volovich, I V; Zagrebnov, V A; Frolov, V P [Joint Inst. for Nuclear Research, Dubna (USSR); AN SSSR, Moscow. Fizicheskij Inst.)

1976-11-01

Particle production in a gravitational field of a black hole with changing mass is considered. It is shown that in the case when parameters are changed adiabatically taking into account the nonstationarity is reduced effectively to the taking into account the dependence of the Hawking radiation temperature on the retarded time.

Cooper’s hawk nest site characteristics in the Pineywoods Region

Science.gov (United States)

Richard R. Schaefer; D. Craig Rudolph; Jesse F. Fagan

2011-01-01

Early accounts describe the Cooper’s Hawk (Accipiter cooperi) as a species in decline in much of North America during the early twentieth century (Bent 1937), particularly when in close proximity to humans (Eaton 1914). This decreasing population trend continued to be recognized later in the century in both Texas (Oberholser 1974) and Louisiana (Lowery 1974). Shooting...

Hawking Radiation from Horizons of Reissner-Nordstroem de Sitter Black Hole with a Global Monopole via Anomalies

International Nuclear Information System (INIS)

Chen Shiwu; Liu Xiongwei; Lin Kai; Zeng Xiaoxiong; Yang Shuzheng

2008-01-01

Hawking radiation from cosmological horizon and event horizon of the Reissner-Nordstroem de Sitter black hole with a global monopole is studied via a new method that was propounded by Robinson and Wilzek and elaborated by Banerjee and Kulkarni. The results show that the gauge current and energy-momentum tensor fluxes, which required keeping gauge covariance and general coordinate invariance at the quantum level in the effective field theory, are exactly equivalent to those of Hawking radiation from the event horizon and the cosmological horizon, respectively

An analysis of Bat Hawk Macheiramphus alcinus diet in the Melaky ...

African Journals Online (AJOL)

We present information on the prey taken by the Bat Hawk Macheiramphus alcinus in two different areas of lowland western central Madagascar. These are the first dietary data from Madagascar for this widespread Old World species. The recovered remains were almost exclusively of bats and birds, with a few examples of ...

Dynamics of the echolocation beam during prey pursuit in aerial hawking bats

DEFF Research Database (Denmark)

Jakobsen, Lasse; Olsen, Mads Nedergaard; Surlykke, Annemarie

2015-01-01

" than the vespertilionids, but ensonifying objects far ahead suggesting more clutter. Thus, beam broadening is not a fundamental property of the echolocation system. However, based on the results, we hypothesize that increased peripheral detection is crucial to all aerial hawking bats in the final...

Nesting habitat and productivity of Swainson's Hawks in southeastern Arizona

Science.gov (United States)

Nishida, Catherine; Boal, Clint W.; DeStefano, Stephen; Hobbs, Royden J.

2013-01-01

We studied Swainson's Hawks (Buteo swainsoni) in southeastern Arizona to assess the status of the local breeding population. Nest success (≥1 young fledged) was 44.4% in 1999 with an average of 1.43 ± 0.09 (SE) young produced per successful pair. Productivity was similar in 2000, with 58.2% nesting success and 1.83 ± 0.09 fledglings per successful pair. Mesquite (Prosopis velutina) and cottonwood (Populus fremontii) accounted for >50% of 167 nest trees. Nest trees were taller than surrounding trees and random trees, and overall there was more vegetative cover at nest sites than random sites. This apparent requirement for cover around nest sites could be important for management of the species in Arizona. However, any need for cover at nest sites must be balanced with the need for open areas for foraging. Density of nesting Swainson's Hawks was higher in agriculture than in grasslands and desert scrub. Breeding pairs had similar success in agricultural and nonagricultural areas, but the effect of rapid and widespread land-use change on breeding distribution and productivity continues to be a concern throughout the range of the species.

Description of the larvae of Hydroporus ferrugineus Stephens and H-polaris fall (Coleoptera: Adephaga: Dytiscidae)

NARCIS (Netherlands)

Alarie, Y.; Wood, P.J.; Bruyn, de A.M.H.; Cuppen, J.G.M.

2001-01-01

Description of structures of the larvae of Hydroporus ferrugineus Stephens and H. polaris Fall is provided including detailed chaetotaxal and porotaxal analyses. Larvae of H. ferrugineus are distinguished from all other species of Hydroporus Clairville by the presence of 1–2 secondary setae on

Down the Rabbit Hole 11/22/63: Stephen King’s Historical Changeling

Directory of Open Access Journals (Sweden)

Latham Betty

2016-06-01

Full Text Available Once something becomes a story and it is appropriated in some way, that story experiences an additional, altered life. The adaptation might echo the original, but it does so in such a way that the original is forever changed. The original becomes a “changeling.” On a personal level we view events that we have “witnessed” through the lens of our own experiences. This is even true when one revisits the past through fiction. The reader or spectator experiences the past through the lens of the adapter. Stephen King admitted to being emotionally invested in the events surrounding the assassination of President John Fitzgerald Kennedy in 1963, and this emotional investment is reflected in his adaptation. Stephen King’s novel, 11-22-63, and its TV adaptation, serve as compelling examples of how emotional responses to the past can inform their adaptations, alter how their audiences explore and re-visit the past, and demonstrate how history and adaptations become changelings. King’s adaptation additionally demonstrates his ability to integrate the Kennedy assassination back into popular culture, inviting and allowing a “new” younger audience (who were not alive at the time of the assassination to “experience” history by accompanying his characters down the rabbit hole of history.

Gaze Step Distributions Reflect Fixations and Saccades: A Comment on Stephen and Mirman (2010)

Science.gov (United States)

Bogartz, Richard S.; Staub, Adrian

2012-01-01

In three experimental tasks Stephen and Mirman (2010) measured gaze steps, the distance in pixels between gaze positions on successive samples from an eyetracker. They argued that the distribution of gaze steps is best fit by the lognormal distribution, and based on this analysis they concluded that interactive cognitive processes underlie eye…

Spin One Hawking Radiation from Dirty Black Holes

OpenAIRE

Petarpa Boonserm; Tritos Ngampitipan; Matt Visser

2013-01-01

A “clean” black hole is a black hole in vacuum such as the Schwarzschild black hole. However in real physical systems, there are matter fields around a black hole. Such a black hole is called a “dirty black hole”. In this paper, the effect of matter fields on the black hole and the greybody factor is investigated. The results show that matter fields make a black hole smaller. They can increase the potential energy to a black hole to obstruct Hawking radiation to propagate. This causes the gre...

Parasite infections in nestling red-shouldered hawks (Buteo lineatus) in northeast Wisconsin.

Science.gov (United States)

King, Janet C; Dubay, Shelli A; Huspeni, Todd C; VanLanen, Andrew R; Gerhold, Richard W

2010-06-01

Red-shouldered hawks (Buteo lineatus) are threatened in Wisconsin and long-term data suggest that nest productivity is low in the state for unknown reasons. Our objective was to determine whether red-shouldered hawks in northeast Wisconsin were infected with parasites that could contribute to low nest productivity. We examined nestlings for the presence of Trichomonas gallinae, Protocalliphora avium, and blood parasites in June 2006 and 2007. We did not detect T. gallinae in throat swabs taken from 24 nestlings in 2007. Ear canals of nestlings were parasitized by P. avium larvae in 10 of 11 (91%) nests and in 22 of 24 (92%) nestlings. Larvae were found in higher intensity in 1 ear relative to the other. Leucocytozoon toddi was present in 90.5% (38/42) of the nestlings. At least 1 bird in each nest was infected. Intensity of L. toddi averaged 48.6 +/- 58.3 infected cells per 2,000 erythrocytes (2.4 +/- 2.9%). No other blood parasites were identified.

Effect of body position on respiratory system volumes in anesthetized red-tailed hawks (Buteo jamaicensis) as measured via computed tomography.

Science.gov (United States)

Malka, Shachar; Hawkins, Michelle G; Jones, James H; Pascoe, Peter J; Kass, Philip H; Wisner, Erik R

2009-09-01

To determine the effects of body position on lung and air-sac volumes in anesthetized and spontaneously breathing red-tailed hawks (Buteo jamaicensis). 6 adult red-tailed hawks (sex unknown). A crossover study design was used for quantitative estimation of lung and air-sac volumes in anesthetized hawks in 3 body positions: dorsal, right lateral, and sternal recumbency. Lung volume, lung density, and air-sac volume were calculated from helical computed tomographic (CT) images by use of software designed for volumetric analysis of CT data. Effects of body position were compared by use of repeated-measures ANOVA and a paired Student t test. Results for all pairs of body positions were significantly different from each other. Mean +/- SD lung density was lowest when hawks were in sternal recumbency (-677 +/- 28 CT units), followed by right lateral (-647 +/- 23 CT units) and dorsal (-630 +/- 19 CT units) recumbency. Mean lung volume was largest in sternal recumbency (28.6 +/- 1.5 mL), followed by right lateral (27.6 +/- 1.7 mL) and dorsal (27.0 +/- 1.5 mL) recumbency. Mean partial air-sac volume was largest in sternal recumbency (27.0 +/- 19.3 mL), followed by right lateral (21.9 +/- 16.1 mL) and dorsal (19.3 +/- 16.9 mL) recumbency. In anesthetized red-tailed hawks, positioning in sternal recumbency resulted in the greatest lung and air-sac volumes and lowest lung density, compared with positioning in right lateral and dorsal recumbency. Additional studies are necessary to determine the physiologic effects of body position on the avian respiratory system.

The STS-95 crew participates in a media briefing before returning to JSC

Science.gov (United States)

1998-01-01

The day after their return to Earth on board the orbiter Discovery, members of the STS-95 crew participate in a media briefing at the Kennedy Space Center Press Site Auditorium before returning to the Johnson Space Center in Houston, Texas. From left to right are Lisa Malone, moderator and chief of NASA Public Affairs' Media Services at Kennedy Space Center; Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialist and Payload Commander Stephen K. Robinson; Mission Specialist Scott E. Parazynski; Mission Specialist Pedro Duque, with the European Space Agency (ESA); Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA); and Payload Specialist John H. Glenn Jr., a senator from Ohio and one of the original seven Project Mercury astronauts. The STS-95 mission ended with landing at Kennedy Space Center's Shuttle Landing Facility at 12:04 p.m. EST on Nov. 7. The mission included research payloads such as the Spartan-201 solar- observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as a SPACEHAB single module with experiments on space flight and the aging process.

Entropy Budget for Hawking Evaporation

Directory of Open Access Journals (Sweden)

Ana Alonso-Serrano

2017-07-01

Full Text Available Blackbody radiation, emitted from a furnace and described by a Planck spectrum, contains (on average an entropy of 3 . 9 ± 2 . 5 bits per photon. Since normal physical burning is a unitary process, this amount of entropy is compensated by the same amount of “hidden information” in correlations between the photons. The importance of this result lies in the posterior extension of this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget for the evaporation process. In order to carry out this calculation, we adopt a variant of the “average subsystem” approach, but consider a tripartite pure system that includes the influence of the rest of the universe, and which allows “young” black holes to still have a non-zero entropy; which we identify with the standard Bekenstein entropy.

First use of halothane in the United States, C. Ronald Stephen, M.D. (1916-2006).

Science.gov (United States)

Giesecke, Adolph H

2008-01-01

Anesthesia is one of the most valued discoveries in all of history. Almost immediately after the first public demonstration of ether anesthesia, a search for a better drug began. Ether, despite its flammability, persisted as the primary inhalation agent for over a hundred years. The breakthrough came with the introduction of a non-flammable volatile anesthetic called halothane in 1955. The drug was approved by the FDA in 1958 and quickly became the most commonly used agent in the United States. It was a quantum leap forward in the safety of anesthetic drugs. It became obsolete in 1988 because of hepatotoxicity. Three eminent anesthesiologists: Drs. Abajian of Vermont, Siker of Pittsburgh and Stephen of Duke could have been the first to use halothane in the USA. My review of the documents and writings of the three confirm that Dr. C. Ronald Stephen of Duke University was indeed the first to use and publish on halothane anesthesia in the USA.

Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.

Directory of Open Access Journals (Sweden)

Colleen T O'Rourke

Full Text Available BACKGROUND: Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. METHODOLOGY/PRINCIPAL FINDINGS: We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33° and wide blind areas (∼82°, but intermediate degree of eye movement (∼5°, which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°, small blind areas (∼60°, and high degree of eye movement (∼8°, which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1° may help stabilize the image when hovering above prey before an attack. CONCLUSIONS: We conclude that: (a there are between-species differences in visual field configuration in these diurnal raptors; (b these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats; (c variations in the degree of eye movement between species appear associated with foraging strategies; and (d the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence

Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.

Science.gov (United States)

O'Rourke, Colleen T; Hall, Margaret I; Pitlik, Todd; Fernández-Juricic, Esteban

2010-09-22

Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33°) and wide blind areas (∼82°), but intermediate degree of eye movement (∼5°), which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°), small blind areas (∼60°), and high degree of eye movement (∼8°), which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1°) may help stabilize the image when hovering above prey before an attack. We conclude that: (a) there are between-species differences in visual field configuration in these diurnal raptors; (b) these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats); (c) variations in the degree of eye movement between species appear associated with foraging strategies; and (d) the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence behavioral strategies to visually search for and track prey while

Comparative morphology among northern populations of breeding Cooper's Hawks

Science.gov (United States)

Rosenfield, Robert N.; Rosenfield, Laura J.; Bielefeldt, John; Murphy, Robert K.; Stewart, Andrew C.; Stout, William E.; Driscoll, Timothy G.; Bozek, Michael A.

2010-01-01

Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada, isolated deciduous woodlands in short-grass prairies of northwestern North Dakota, towns and rural deciduous woodlands along the border of North Dakota and Minnesota, and urban and rural mixed deciduous and coniferous landscapes of Wisconsin. These sites span 2660 km across the northern part of the species' breeding range. We measured body mass (i.e., size), wing chord, tail length, tarsus diameter, hallux length, and culmen length of breeding adults, finding significant and clinal variation in body mass (or size). The smallest and most similar-sized birds occurred in British Columbia and western North Dakota, larger birds along the border between North Dakota and Minnesota, and the largest birds in Wisconsin. Several other characters varied significantly when mass was used as a covariate. Variation by study site in mean indices of sexual size dimorphism was negligible and not significant. We speculate that the morphological differences we found, in part, are the result of geographic isolation, where diets, migratory behavior, and structural characteristics of nesting habitats vary across landscape types.

The High Altitude MMIC Sounding Radiometer on the GLOBAL HAWK: From Technology Development to Science Discovery

Science.gov (United States)

Brown, Shannon; Denning, Richard; Lambrigtsen, Bjorn; Lim, Boon; Tanabe, Jordan; Tanner, Alan

2013-01-01

This paper presents results from the High Altitude MMIC Sounding Radiometer (HAMSR) during three recent field campaigns on the Global Hawk Unmanned Ariel Vehicles (UAV), focusing on the enabling technology that led to unprecedented observations of significant weather phenomenon, such as thermodynamic evolution of the tropical cyclone core during rapid intensification and the high resolution three dimensional mapping of several atmospheric river events. HAMSR is a 25 channel cross-track scanning microwave sounder with channels near the 60 and 118 GHz oxygen lines and the 183 GHz water vapor line. HAMSR was originally designed and built at the Jet Propulsion Laboratory as a technology demonstrator in 1998. Subsequent to this, HAMSR participated in three NASA hurricane field campaigns, CAMEX-4, TCSP and NAMMA. Beginning in 2008, HAMSR was extensively upgraded to deploy on the NASA Global Hawk (GH) platform and serve as an asset to the NASA sub-orbital program. HAMSR has participated on the Global Hawk during the 2010 Genesis and Rapid Intensification (GRIP) campaign, the 2011 Winter Storms and Atmospheric Rivers (WISPAR) campaign and is currently participating in the NASA Ventures Hurricane and Severe Storm Sentinel (HS3) campaign (2011-2015).

Hawking, fiducial, and free-fall temperature of black hole on gravity's rainbow

Energy Technology Data Exchange (ETDEWEB)

Gim, Yongwan; Kim, Wontae [Sogang University, Department of Physics, Seoul (Korea, Republic of)

2016-03-15

On gravity's rainbow, the energy of test particles deforms the geometry of a black hole in such a way that the corresponding Hawking temperature is expected to be modified. It means that the fiducial and free-fall temperatures on the black hole background should also be modified according to deformation of the geometry. In this work, the probing energy of test particles is assumed as the average energy of the Hawking particle in order to study the particle back reaction of the geometry by using the advantage of gravity's rainbow. We shall obtain the modified fiducial and free-fall temperatures, respectively. The behaviors of these two temperatures on the horizon tell us that black hole complementarity is still well defined on gravity's rainbow. (orig.)

Liberalism is always greener on the other side of Mill: a reply to Piers Stephens

NARCIS (Netherlands)

Wissenburg, M.L.J.

2001-01-01

Given our shared interest in giving green political thought a basis in liberalism, I discuss five of Piers Stephens' objections to Green Liberalism. (1) I deny that I use preferences as black boxes, prejudicing liberalism in favour of a human-nature divide. (2) I argue that my characterisation of

HOME RANGE AND HABITAT USE OF SUBURBAN RED-SHOULDERED HAWKS IN SOUTHWESTERN OHIO

Science.gov (United States)

Suburban habitats may provide different resources and different challenges to raptors than do more traditional, rural habitats. Suburban red-shouldered hawks (Buteo lineatus) of the eastern subspecies have been little studied. We measured the home ranges and habitat use of 11 su...

The Least Particle Theory

Science.gov (United States)

Hartsock, Robert

2011-10-01

The Least Particle Theory states that the universe was cast as a great sea of energy. MaX Planck declared a quantum of energy to be the least value in the universe. We declare the quantum of energy to be the least particle in the universe. Stephen Hawking declared quantum mechanics to be of no value in todays gross mechanics. That's like saying the number 1 has no place in mathematics.

The Large, the Small and the Human Mind

Science.gov (United States)

Penrose, Roger; Longair, Malcolm; Abner Shimony, With; Cartwright, Nancy; Hawking, Stephen

2000-05-01

Foreword Malcolm Longair; 1. Space-time and cosmology Roger Penrose; 2. The mysteries of quantum physics Roger Penrose; 3. Physics and the mind Roger Penrose; 4. On mentality, quantum mechanics and the actualization of potentialities Abner Shimony; 5. Why physics? Nancy Cartwright; 6. The objections of an unashamed reductionist Stephen Hawking; 7. Response Roger Penrose; Appendix I: Goodstein's theorm and mathematical thinking; Appendix II: Experiments to test gravitationally induced state reduction.

The Celebrity Scientists

OpenAIRE

Fahy, Declan

2010-01-01

This collective case study examines how four contemporary British scientists and popular science writers, Stephen Hawking, Richard Dawkins, Susan Greenfield and James Lovelock, are portrayed in mass media as celebrities. It finds that the scientists’ private and public lives merge in their representations, their images commodified and marketed by the cultural industries, their mediated personae embodying abstract ideas of truth and reason. The celebrity scientists base their authority on thei...

The Future of (Artificial) Intelligence

CERN Multimedia

CERN. Geneva

2016-01-01

The news media in recent months have been full of dire warnings about the risk that AI poses to the human race, coming from well-known figures such as Stephen Hawking, Frank Wilczek and Elon Musk. Should we be concerned? If so, what can we do about it? While some in the mainstream AI community dismiss these concerns, I will argue instead that a fundamental reorientation of the field is required.

Hawking effect and quantum nonthermal radiation of an arbitrarily accelerating charged black hole using a new tortoise coordinate transformation

International Nuclear Information System (INIS)

Pan Wei-Zhen; Yang Xue-Jun; Xie Zhi-Kun

2011-01-01

Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour—Ruffini method. After the tortoise coordinate transformation, the Klein—Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton—Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable. (geophysics, astronomy, and astrophysics)

Festschrift in the honor of Stephen H. White's 70th Birthday.

Science.gov (United States)

Bondar, Ana-Nicoleta; Woolf, Thomas B; Tobias, Douglas J

2011-01-01

The Symposium 'Frontiers in membrane and membrane protein biophysics: experiments and theory', held this year at the University of California, Irvine (August 19-20), celebrated the 70th Birthday of Stephen H. White by bringing together distinguished experimentalists and theoreticians to discuss the state of the art and future challenges in the field of membrane and membrane protein biophysics. The meeting and this special issue highlight the highly interdisciplinary nature of membrane and membrane protein biophysics, and the tremendous contributions that S. H. White and his lab have brought to the field.

George's cosmic treasure hunt

CERN Document Server

Hawking, Lucy; Parsons, Gary

2009-01-01

George and Annie explore the galaxy in this cosmic adventure from Stephen Hawking and Lucy Hawking, complete with essays from Professor Hawking about the latest in space travel. George is heartbroken when he learns that his friend Annie and her father are moving to the US. Eric has a new job working for the space program, looking for signs of life in the Universe. Eric leaves George with a gift—a book called The User’s Guide to the Universe. But Annie and Eric haven’t been gone for very long when Annie believes that she is being contacted by aliens, who have a terrible warning for her. George joins her in the US to help her with her quest—and before he knows it, he, Annie, Cosmos, and Annie’s annoying cousin Emmett have been swept up in a cosmic treasure hunt, spanning the whole galaxy and beyond. Lucy Hawking's own experiences in zero-gravity flight and interviews with astronauts at Cape Kennedy and the Johnson Space Center lend the book a sense of realism and excitement that is sure to fire up ima...

Wrestling with Stephen and Matilda: Planning Challenging Enquiries to Engage Year 7 in Medieval Anarchy

Science.gov (United States)

McDougall, Hannah

2013-01-01

McDougall found learning about Stephen and Matilda fascinating, was sure that her pupils would also and designed an enquiry to engage them in "the anarchy" of 1139-1153 AD. Pupils enjoyed exploring "the anarchy" and learning about it enhanced their knowledge and understanding of the medieval period considerably. However,…

Lorentz Invariance Violation and Modified Hawking Fermions Tunneling Radiation

Directory of Open Access Journals (Sweden)

Shu-Zheng Yang

2016-01-01

Full Text Available Recently the modified Dirac equation with Lorentz invariance violation has been proposed, which would be helpful to resolve some issues in quantum gravity theory and high energy physics. In this paper, the modified Dirac equation has been generalized in curved spacetime, and then fermion tunneling of black holes is researched under this correctional Dirac field theory. We also use semiclassical approximation method to get correctional Hamilton-Jacobi equation, so that the correctional Hawking temperature and correctional black hole’s entropy are derived.

Comparison of three different inhalant anesthetic agents (isoflurane, sevoflurane, desflurane) in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Granone, Tiffany D; de Francisco, Olga N; Killos, Maria B; Quandt, Jane E; Mandsager, Ron E; Graham, Lynelle F

2012-01-01

To compare isoflurane, sevoflurane and desflurane for inhalant anesthesia in red-tailed hawks (Buteo jamaicensis) in terms of the speed and characteristics of induction; cardiovascular and respiratory parameters while anesthetized; and speed and quality of recovery. Prospective, cross over, randomized experimental study. 12 healthy adult red-tailed hawks. Anesthesia was induced with isoflurane, sevoflurane or desflurane in oxygen via face mask in a crossover, randomized design with a 1 week washout period between each treatment. Hawks were tracheally intubated, allowed to breathe spontaneously, and instrumented for cardiopulmonary monitoring. Data collected included heart rate, respiratory rate, end-tidal CO(2) , inspired and expired agent, SpO(2,) temperature, systolic blood pressure, time to intubation and time to recovery (tracking). Recovery was subjectively scored on a 4 point scale as well as a summary evaluation, by a single blinded observer. No significant difference in time to induction and time to extubation was noted with the administration of isoflurane, sevoflurane or desflurane. Time to the ability of the bird to follow a moving object with its eyes (tracking) was significantly faster with the administration of sevoflurane and desflurane. All recoveries were scored 1 or 2 and were assessed as good to excellent. No significant difference was noted in heart rate, blood pressure and temperature among the three inhalants. Administration of isoflurane resulted in lower respiratory rates. Overall, although isoflurane remains the most common inhaled anesthetic in avian practice, sevoflurane and desflurane both offer faster time to tracking, while similar changes in cardiopulmonary function were observed with each agent during anesthesia of healthy red-tailed hawks. © 2011 The Authors. Veterinary Anaesthesia and Analgesia. © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

Une brève histoire du temps du Big Bang aux trous noirs

CERN Document Server

Hawking, Stephen

2017-01-01

Stephen Hawking est universellement reconnu comme l'un des plus grands cosmologistes de notre époque et l'un des plus brillants physiciens depuis Einstein. Successeur de Newton, il occupe à l'université de Cambridge la chaire de Mathématiques, et s'est rendu célèbre pour ses travaux sur les origines de l'Univers. Une brève histoire du temps est le premier livre qu'il ait décidé d'écrire pour le non-spécialiste. Il y expose, dans un langage simple et accessible, les plus récents développements de l'astrophysique concernant la nature du temps et du monde. Retraçant les grandes théories du cosmos, de Galilée et Newton à Einstein et Poincaré, racontant les ultimes découvertes de l'espace, expliquant la nature des trous noirs, il propose ensuite de relever le plus grand défi de la science moderne : la recherche d'une théorie unitaire combinant et unifiant la relativité générale et la mécanique quantique. On sait que Stephen Hawking lutte depuis plus de trente ans contre une maladie neurolo...

The Future of Theoretical Physics and Cosmology

Science.gov (United States)

Gibbons, G. W.; Shellard, E. P. S.; Rankin, S. J.

2009-08-01

Preface; List of contributors; 1. Introduction; Part I. Popular Symposium: 2. Our complex cosmos and its future Martin J. Rees; 3. Theories of everything and Hawking's wave function of the Universe James B. Hartle; 4. The problem of space-time singularities: implications for quantum gravity? Roger Penrose; 5. Warping spacetime Kip Thorne; 6. 60 years in a nutshell Stephen W. Hawking; Part II. Spacetime Singularities: 7. Cosmological perturbations and singularities George F. R. Ellis; 8. The quantum physics of chronology protection Matt Visser; 9. Energy dominance and the Hawking-Ellis vacuum conservation theorem Brandon Carter; 10. On the instability of extra space dimensions Roger Penrose; Part III. Black Holes: 11. Black hole uniqueness and the inner horizon stability problem Werner Israel; 12. Black holes in the real universe and their prospects as probes of relativistic gravity Martin J. Rees; 13. Primordial black holes Bernard Carr; 14. Black hole pair creation Simon F. Ross; 15. Black holes as accelerators Steven Giddings; Part IV. Hawking Radiation: 16. Black holes and string theory Malcolm Perry; 17. M theory and black hole quantum mechanics Joe Polchinski; 18. Playing with black strings Gary Horowitz; 19. Twenty years of debate with Stephen Leonard Susskind; Part V. Quantum Gravity: 20. Euclidean quantum gravity: the view from 2002 Gary Gibbons; 21. Zeta functions, anomalies and stable branes Ian Moss; 22. Some reflections on the status of conventional quantum theory when applied to quantum gravity Chris Isham; 23. Quantum geometry and its ramifications Abhay Ashtekar; 24. Topology change in quantum gravity Fay Dowker; Part VI. M Theory and Beyond: 25. The past and future of string theory Edward Witten; 26. String theory David Gross; 27. A brief description of string theory Michael Green; 28. The story of M Paul Townsend; 29. Gauged supergravity and holographic field theory Nick Warner; 30. 57 varieties in a NUTshell Chris Pope; Part VII. de Sitter Space

Universal Property of Quantum Gravity implied by Bekenstein-Hawking Entropy and Boltzmann formula

International Nuclear Information System (INIS)

Saida, Hiromi

2013-01-01

We search for a universal property of quantum gravity. By u niversal , we mean the independence from any existing model of quantum gravity (such as the super string theory, loop quantum gravity, causal dynamical triangulation, and so on). To do so, we try to put the basis of our discussion on theories established by some experiments. Thus, we focus our attention on thermodynamical and statistical-mechanical basis of the black hole thermodynamics: Let us assume that the Bekenstein-Hawking entropy is given by the Boltzmann formula applied to the underlying theory of quantum gravity. Under this assumption, the conditions justifying Boltzmann formula together with uniqueness of Bekenstein-Hawking entropy imply a reasonable universal property of quantum gravity. The universal property indicates a repulsive gravity at Planck length scale, otherwise stationary black holes can not be regarded as thermal equilibrium states of gravity. Further, in semi-classical level, we discuss a possible correction of Einstein equation which generates repulsive gravity at Planck length scale.

Confluent Heun functions and the physics of black holes: Resonant frequencies, Hawking radiation and scattering of scalar waves

Energy Technology Data Exchange (ETDEWEB)

Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

2016-10-15

We apply the confluent Heun functions to study the resonant frequencies (quasispectrum), the Hawking radiation and the scattering process of scalar waves, in a class of spacetimes, namely, the ones generated by a Kerr–Newman–Kasuya spacetime (dyon black hole) and a Reissner–Nordström black hole surrounded by a magnetic field (Ernst spacetime). In both spacetimes, the solutions for the angular and radial parts of the corresponding Klein–Gordon equations are obtained exactly, for massive and massless fields, respectively. The special cases of Kerr and Schwarzschild black holes are analyzed and the solutions obtained, as well as in the case of a Schwarzschild black hole surrounded by a magnetic field. In all these special situations, the resonant frequencies, Hawking radiation and scattering are studied. - Highlights: • Charged massive scalar field in the dyon black hole and massless scalar field in the Ernst spacetime are analyzed. • The confluent Heun functions are applied to obtain the solution of the Klein–Gordon equation. • The resonant frequencies are obtained. • The Hawking radiation and the scattering process of scalar waves are examined.

Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Sadar, Miranda J; Hawkins, Michelle G; Byrne, Barbara A; Cartoceti, Andrew N; Keel, Kevin; Drazenovich, Tracy L; Tell, Lisa A

2015-12-01

To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis). 7 adult nonreleasable healthy red-tailed hawks. In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed. Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 μg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 μg/mL and target plasma ceftiofur concentration of 4 μg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively. Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.

School Choice Research in Five European Countries: The Circulation of Stephen Ball's Concepts and Interpretations

Science.gov (United States)

van Zanten, Agnès; Kosunen, Sonja

2013-01-01

This article analyzes the influence of Stephen Ball's work on research on markets and school choice in five European countries (Finland, France, Norway, Spain, and Sweden). The main focus is on the intellectual circulation of ideas, but the authors also take into account the relationship between ideas and social and political changes, as well as…

Contributions of Stephen J. Ball to the Research on Educational and Curriculum Policies in Brazil

Science.gov (United States)

Mainardes, Jefferson; Gandin, Luis Armando

2013-01-01

This article aims at showcasing the main contributions of Stephen J. Ball to educational research in Brazil, particularly to the study of educational and curriculum policies. We also highlight some of the limitations in the incorporation of Ball's ideas in Brazil as well as some of the challenges that these author's ideas pose to Brazilian…

Global Hawk dropsonde observations of the Arctic atmosphere obtained during the Winter Storms and Pacific Atmospheric Rivers (WISPAR field campaign

Directory of Open Access Journals (Sweden)

J. M. Intrieri

2014-11-01

Full Text Available In February and March of 2011, the Global Hawk unmanned aircraft system (UAS was deployed over the Pacific Ocean and the Arctic during the Winter Storms and Pacific Atmospheric Rivers (WISPAR field campaign. The WISPAR science missions were designed to (1 mprove our understanding of Pacific weather systems and the polar atmosphere; (2 evaluate operational use of unmanned aircraft for investigating these atmospheric events; and (3 demonstrate operational and research applications of a UAS dropsonde system at high latitudes. Dropsondes deployed from the Global Hawk successfully obtained high-resolution profiles of temperature, pressure, humidity, and wind information between the stratosphere and surface. The 35 m wingspan Global Hawk, which can soar for ~ 31 h at altitudes up to ~ 20 km, was remotely operated from NASA's Dryden Flight Research Center at Edwards Air Force Base (AFB in California. During the 25 h polar flight on 9–10 March 2011, the Global Hawk released 35 sondes between the North Slope of Alaska and 85° N latitude, marking the first UAS Arctic dropsonde mission of its kind. The polar flight transected an unusually cold polar vortex, notable for an associated record-level Arctic ozone loss, and documented polar boundary layer variations over a sizable ocean–ice lead feature. Comparison of dropsonde observations with atmospheric reanalyses reveal that, for this day, large-scale structures such as the polar vortex and air masses are captured by the reanalyses, while smaller-scale features, including low-level jets and inversion depths, are mischaracterized. The successful Arctic dropsonde deployment demonstrates the capability of the Global Hawk to conduct operations in harsh, remote regions. The limited comparison with other measurements and reanalyses highlights the potential value of Arctic atmospheric dropsonde observations where routine in situ measurements are practically nonexistent.

A remark on the energy conditions for Hawking's area theorem

Science.gov (United States)

Lesourd, Martin

2018-06-01

Hawking's area theorem is a fundamental result in black hole theory that is universally associated with the null energy condition. That this condition can be weakened is illustrated by the formulation of a strengthened version of the theorem based on an energy condition that allows for violations of the null energy condition. With the semi-classical context in mind, some brief remarks pertaining to the suitability of the area theorem and its energy condition are made.

An Eminent Specialist in Both Chinese Literature and Comparative Literature—An Interview with Prof.Stephen Owen

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

<正>The Interviewee:Stephen Owen,James Bryant Conant University Professor and a member of American Academy of Arts and Sciences(1991-),is working at Harvard University as Professor of Comparative Literature in the Dept.of Comparative Literature and Professor of Chinese Literature in the Dept.of Asian Studies.

Artificial-life researchers try to create social reality.

Science.gov (United States)

Flam, F

1994-08-12

Some scientists, among them cosmologist Stephen Hawking, argue that computer viruses are alive. A better case might be made for many of the self-replicating silicon-based creatures featured at the fourth Conference on Artificial Life, held on 5 to 8 July in Boston. Researchers from computer science, biology, and other disciplines presented computer programs that, among other things, evolved cooperative strategies in a selfish world and recreated themselves in ever more complex forms.

Verification of Meteorological Data Reports from the RQ-4A Global Hawk Unmanned Aerial Vehicle

National Research Council Canada - National Science Library

Callis, Steven

2004-01-01

... intelligence for military planners. The value of any dataset is directly related to its accuracy and this research determined the accuracy of weather data obtained from a particular UAV, the RQ-4A Global Hawk...

Torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Kerrigan, Shannon M; Kapatkin, Amy S; Garcia, Tanya C; Robinson, Duane A; Guzman, David Sanchez-Migallon; Stover, Susan M

2018-04-01

OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis). SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks. PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined. RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties. CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

Correction to Hawking radiation of the stationary axisymmetric NUT-Taub black hole

International Nuclear Information System (INIS)

Li Huiling; Lin Rong; Cai Min; Qi Dejiang; Jiang Qingquan

2007-01-01

Adopting a new method of quantum radiation as tunnelling, and taking energy conservation into account, the tunnelling radiation characteristics of the stationary axial symmetric NUT-Taub black hole are studied. The result shows that the tunnelling rate of particles at the event horizon of the black hole is relevant to Bekenstein-Hawking entropy and the real spectrum is not precisely thermal at all

Quantum anomalies at horizon and Hawking radiations in Myers-Perry black holes

International Nuclear Information System (INIS)

Iso, Satoshi; Morita, Takeshi; Umetsu, Hiroshi

2007-01-01

A new method has been developed recently to derive Hawking radiations from black holes based on considerations of gravitational and gauge anomalies at the horizon. In this paper, we apply the method to Myers-Perry black holes with multiple angular momenta in various dimensions by using the dimensional reduction technique adopted in the case of four-dimensional rotating black holes

Christopher Hawkes and the International Summer Courses of Ampurias

Directory of Open Access Journals (Sweden)

Margarita Díaz-Andreu

2007-05-01

Full Text Available This article aims to provide an initial analysis of the early connections between Christopher Hawkes and Spanish archaeology in the context of his participation in two of the international summer courses in Ampurias in 1947 and 1950. The documentation used for this article comes mainly from the Pericot Archive in the Library of Catalonia, in which there are 43 letters from Hawkes to Pericot between 1940 and 1975. In addition, other correspondence in the British Museum and in the Ministry of Foreign Affairs will be mentioned. This study forms part of a larger project of recovering the memory of twentieth-century British-Spanish relations, of which a first phase has centred on the assessment of Gordon Childe’s contacts with Spain (Díaz-Andreu 1998; forthcoming–a; forthcoming–b. As in Gordon Childe’s case, all memory of Hawkes’ visits, and indeed of his relationships with Spanish archaeologists, has since been lost. Unfortunately, this situation is not exceptional: most of the links between Spanish archaeologists and British and American archaeologists in the twenty years around the Spanish Civil War have dropped out of archaeological memory. To the names mentioned in a recent seminar (Gordon Childe, Edward Thurlow Leeds, Eoin MacWhite, Hubert Savory (Armada Pita 2006, many others could be added. As this article will show, however, there were many contacts and these help to explain some developments in the archaeological thinking and practice of the participants involved in these exchanges, as well as some events in the international organisation of archaeology.

The B4 school check behaviour measures: findings from the Hawke's Bay evaluation.

Science.gov (United States)

Hedley, Cath; Thompson, Shona; Morris Matthews, Kay; Pentecost, Mandy; Wivell, Judy; Frost, Ariana Stockdale; Morris, Helen

2012-11-01

The Before (B4) School Check is a free health and development check delivered by specifically trained nurses to four year old children throughout New Zealand, aimed to identify and address any health, behavioural, social or developmental concerns that could affect a child's ability to get the most benefit from school. Reported here are the results of an evaluation of the B4 School Checks in Hawke's Bay, focusing specifically on children assessed at the 84 School Check with behaviour issues as determined by the Strengths and Difficulties Questionnaire (SDQ). Health Hawke's Bay (HHB) records were reviewed to understand the number and demographics of the children assessed with behaviour issues at the B4 School Checks up to 31 August 2011, and the interventions to which they were referred. Telephone Interviews were conducted with 36 parents/caregivers of these children to address the questions, what difference did the B4 School Check make to children assessed with behaviour issues and what aspects of the B4 School Check delivery contributed to successful outcomes for these children? Results showed that child behaviour issues in Hawke's Bay were identified in more boys than girls and concentrated in more deprived families. Māori children were represented in numbers disproportional to the regional population. The majority of referrals for child behaviour directed parents/caregivers to non-governmental organisations for family support and parenting programmes. Thematic analysis was applied to the qualitative data derived from the interviews with parents/caregivers and results indicated high levels of satisfaction with the B4 School Check for behaviour and the referred outcomes. Implications for nursing practice arise from these findings in that they identify factors which contribute to what does and does not work well for achieving successful outcomes from the B4 School Check for behaviour.

Hawking radiation and the boomerang behavior of massive modes near a horizon

Science.gov (United States)

Jannes, G.; Maïssa, P.; Philbin, T. G.; Rousseaux, G.

2011-05-01

We discuss the behavior of massive modes near a horizon based on a study of the dispersion relation and wave packet simulations of the Klein-Gordon equation. We point out an apparent paradox between two (in principle equivalent) pictures of black-hole evaporation through Hawking radiation. In the picture in which the evaporation is due to the emission of positive-energy modes, one immediately obtains a threshold for the emission of massive particles. In the picture in which the evaporation is due to the absorption of negative-energy modes, such a threshold apparently does not exist. We resolve this paradox by tracing the evolution of the positive-energy massive modes with an energy below the threshold. These are seen to be emitted and move away from the black-hole horizon, but they bounce back at a “red horizon” and are reabsorbed by the black hole, thus compensating exactly for the difference between the two pictures. For astrophysical black holes, the consequences are curious but do not affect the terrestrial constraints on observing Hawking radiation. For analogue-gravity systems with massive modes, however, the consequences are crucial and rather surprising.

HURRICANE AND SEVERE STORM SENTINEL (HS3) GLOBAL HAWK HIGH ALTITUDE MMIC SOUNDING RADIOMETER (HAMSR) V1

Data.gov (United States)

National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Global Hawk High Altitude MMIC Sounding Radiometer (HAMSR) datasets include measurements gathered by the HAMSR...

Behavioural ecology, distribution and conservation of the Javan Hawk-eagle Spizaetus bartelsi Stresemann, 1924

NARCIS (Netherlands)

Sözer, Resit; Nijman, Vincent

1995-01-01

In the period December 1993 – January 1995 research on the behavioural ecology, distribution and conservation of the Javan Hawk-eagle Spizaetus bartelsi was carried out by R. Sözer and V. Nijman, under supervision of BirdLife International / PHPA – Indonesia Programme. This research was part of the

From Spectator to User, From Viewer to (Act)or

OpenAIRE

Mitakou, E. N.; Fanou, P.; Zamani, Efpraxia D.

2013-01-01

Stephen Hawking, when introducing Krauss’ ‘The Physics of Star Trek’, wrote that “[s]cience fiction (…) is not only good fun but it also serves a serious purpose, that of expanding the human imagination.” In this paper, following a retrospective juxtaposition of the two last centuries’ filmic production, we show how imaginary worlds have become conventional and familiar, while viewers have transformed from mere spectators to users of intelligent technologies. We also exhibit...

Public opinion and the politics of the killer robots debate

OpenAIRE

Michael C Horowitz

2016-01-01

The possibility that today’s drones could become tomorrow’s killer robots has attracted the attention of people around the world. Scientists and business leaders, from Stephen Hawking to Elon Musk, recently signed a letter urging the world to ban autonomous weapons. Part of the argument against these systems is that they violate the public conscience provision of the Martens Clause due to public opposition, making them illegal under international law. What, however, does the US public think o...

Using H. Stephen Glenn's Developing Capable People Program with Adults in Montana: How Effective Is the Curriculum?

Science.gov (United States)

Astroth, Kirk A.; Lorbeer, Scott

1998-01-01

Pre/posttest scores of 30 participants in H. Stephen Glenn's Developing Capable People (DCP) program offered by Montana Extension showed that DCP effectively increased the use of positive behaviors and decreased negative behaviors in adults interacting with youth. These changes were sustained over 18 months after program completion. (SK)

Feeding ecology of sharp-shinned hawks in deciduous and coniferous forests in Colorado

Science.gov (United States)

Suzanne M. Joy; Richard T. Reynolds; Richard L. Knight; Richard W. Hoffman

1994-01-01

Feeding ecology of 11 Sharp-skinned Hawk (Accipiter striates) pairs nesting in aspen (Populus tremuloides), conifer (Abies, Picea spp.), and mixed aspen-conifer habitats in southwest Colorado was investigated during 1988-1989. Small birds (x-bar = 20.9 g, SE = 0.8 g) and mammals (x-bar = 41.1 g, SE = 3.3 g) comprised 91 and 9% of...

UH-60 Black Hawk Disturbance Rejection Study for Hover/Low Speed Handling Qualities Criteria and Turbulence Modeling

National Research Council Canada - National Science Library

Labows, Steven

2000-01-01

.... This paper discusses the airborne flight test of the Sikorsky UH-60 Black Hawk helicopter in turbulent conditions to determine disturbance rejection criteria and to develop a low speed turbulence...

Bekenstein-Hawking Entropy and Strange Metals

Directory of Open Access Journals (Sweden)

Subir Sachdev

2015-11-01

Full Text Available We examine models of fermions with infinite-range interactions that realize non-Fermi liquids with a continuously variable U(1 charge density Q and a nonzero entropy density S at vanishing temperature. Real-time correlators of operators carrying U(1 charge q at a low temperature T are characterized by a Q-dependent frequency ω_{S}=(qT/ℏ(∂S/∂Q, which determines a spectral asymmetry. We show that the correlators match precisely with those of the two-dimensional anti–de Sitter (AdS_{2} horizons of extremal charged black holes. On the black hole side, the matching employs S as the Bekenstein-Hawking entropy density and the laws of black hole thermodynamics that relate (∂S/∂Q/(2π to the electric field strength in AdS_{2}. The fermion model entropy is computed using the microscopic degrees of freedom of a UV complete theory without supersymmetry.

S-7OA-9 Black Hawk Helicopter: Internal Panel Cracking Investigation

Science.gov (United States)

1997-01-01

research into helicopter usage monitoring and is involved with a sub-committee of TTCP HTP 8 looking at issues related to helicopter usage monitoring. He is...Repair Manual . It was subsequently discovered that a majority of the ESSS struts in service had the same damage and this raised an airworthiness issue...Black Hawk Structural Repair Manual , Royal Australian Air Force Publication, DI(AF) AAP7210.015-3,12 May 1994. 15. Fraser, R.C., A One-Pass Method For

Hawking tunneling and boomerang behaviour of massive particles with E < m

Science.gov (United States)

Jannes, Gil; Philbin, Thomas G.; Rousseaux, Germain

2012-07-01

Massive particles are radiated from black holes through the Hawking mechanism together with the more familiar radiation of massless particles. For E >= m, the emission rate is identical to the massless case. But E boomerang. The tunneling formalism is used to calculate the probability for detecting such E < m particles, for a Schwarzschild black hole of astrophysical size or in an analogue gravity experiment, as a function of the distance from the horizon and the energy of the particle.

Habitat associations of sympatric red-tailed hawks and northern goshawks on the Kaibab Plateau

Science.gov (United States)

Frank A. La Sorte; R. William Mannan; Richard T. Reynolds; Teryl G. Grubb

2004-01-01

We investigated habitat association of sympatric red-tailed hawks (Buteo jamaicensis) and northern goshawks (Accipiter gentilis) at 2 spatial scales centered on nest sites: (1) fine-scale patterns of forest structure and topography within 16-m radius circles (0.08 ha), and (2) midscale patterns of forested and nonforested areas,...

Geologic map of the Stephens City quadrangle, Clark, Frederick, and Warren Counties, Virginia

Science.gov (United States)

Weary, D.J.; Orndorff, R.C.; Aleman-Gonzalez, W.

2006-01-01

The Stephens City 1:24,000-scale quadrangle is one of several quadrangles in Frederick County, Virginia being mapped by geologists from the U.S. Geological Survey in Reston, VA with funding from the National Cooperative Geologic Mapping Program. This work is part of a project being lead by the U.S. Geological Survey Water Resources Discipline, Virginia District, to investigate the geologic framework and groundwater resources of Frederick County as well as other areas in the northern Shenandoah Valley of Virginia and West Virginia.

Advanced MicroObserver UGS integration with and cueing of the BattleHawk squad level loitering munition and UAV

Science.gov (United States)

Steadman, Bob; Finklea, John; Kershaw, James; Loughman, Cathy; Shaffner, Patti; Frost, Dean; Deller, Sean

2014-06-01

Textron's Advanced MicroObserver(R) is a next generation remote unattended ground sensor system (UGS) for border security, infrastructure protection, and small combat unit security. The original MicroObserver(R) is a sophisticated seismic sensor system with multi-node fusion that supports target tracking. This system has been deployed in combat theaters. The system's seismic sensor nodes are uniquely able to be completely buried (including antennas) for optimal covertness. The advanced version adds a wireless day/night Electro-Optic Infrared (EOIR) system, cued by seismic tracking, with sophisticated target discrimination and automatic frame capture features. Also new is a field deployable Gateway configurable with a variety of radio systems and flexible networking, an important upgrade that enabled the research described herein. BattleHawkTM is a small tube launched Unmanned Air Vehicle (UAV) with a warhead. Using transmitted video from its EOIR subsystem an operator can search for and acquire a target day or night, select a target for attack, and execute terminal dive to destroy the target. It is designed as a lightweight squad level asset carried by an individual infantryman. Although BattleHawk has the best loiter time in its class, it's still relatively short compared to large UAVs. Also it's a one-shot asset in its munition configuration. Therefore Textron Defense Systems conducted research, funded internally, to determine if there was military utility in having the highly persistent MicroObserver(R) system cue BattleHawk's launch and vector it to beyond visual range targets for engagement. This paper describes that research; the system configuration implemented, and the results of field testing that was performed on a government range early in 2013. On the integrated system that was implemented, MicroObserver(R) seismic detections activated that system's camera which then automatically captured images of the target. The geo-referenced and time-tagged Micro

Solar space heating for the Visitors Center, Stephens College, Columbia, Missouri

Science.gov (United States)

1980-01-01

The solar energy system located at the Visitors' Center on the Stephens College Campus, Columbia, Missouri is discussed. The system is installed in a four-story, 15,000 square foot building. The solar energy system is an integral design of the building and utilizes 176 hydronic flat plate collectors which use a 50 percent water ethylene blycol solution and water-to-water heat exchanger. Solar heated water is stored in a 5,000 gallon water storage tank located in the basement equipment room. A natural gas fired hot water boiler supplies hot water when the solar energy heat supply fails to meet the demand. The designed solar contribution is 71 percent of the heating load.

Stephen Greenblatt. El Giro: De cómo un manuscrito olvidado contribuyó a crear el mundo moderno.

Directory of Open Access Journals (Sweden)

Ángel J. Traver Vera

2013-12-01

Full Text Available Reseña de Stephen Greenblatt, El Giro: De cómo un manuscrito olvidado contribuyó a crear el mundo moderno (Trad. castellana de J. Rabasseda y T. De Lozoya. Barcelona : Ed. Crítica, 2012, 319 pp. ISBN: 978-8498924121.

Power distribution in the hovering flight of the hawk moth Manduca sexta

International Nuclear Information System (INIS)

Zhao Liang; Deng Xinyan

2009-01-01

We investigated inertial and aerodynamic power consumption during hovering flight of the hawk moth Manduca sexta. The aerodynamic power was estimated based on the aerodynamic forces and torques measured on model hawk-moth wings and hovering kinematics. The inertial power was estimated based on the measured wing mass distribution and hovering kinematics. The results suggest that wing inertial power (without consideration of muscle efficiency and elastic energy storage) consumes about half of the total power expenditure. Wing areal mass density was measured to decrease sharply from the leading edge toward the trailing edge and from the wing base to the wing tip. Such a structural property helps to minimize the wing moment of inertia given a fixed amount of mass. We measured the aerodynamic forces on the rigid and flexible wings, which were made to approximate the flexural stiffness (EI) distribution and deformation of moth wings. It has been found that wings with the characteristic spanwise and chordwise decreasing EI (and mass density) are beneficial for power efficiency while generating aerodynamic forces comparative to rigid wings. Furthermore, negative work to aid pitching in stroke reversals from aerodynamic forces was found, and it showed that the aerodynamic force contributes partially to passive pitching of the wing

Stephen Neidle on cancer therapy and G-quadruplex inhibitors. Interview by Joanna De Souza.

Science.gov (United States)

Neidle, Stephen

2004-09-15

Stephen Neidle was educated at Imperial College, London, where he graduated in chemistry and then proceeded to do a PhD in crystallography. After a period as an ICI Fellow, he joined the Biophysics Department at King's College, which ignited his interest in nucleic acid structural studies. He was appointed as one of the first Cancer Research Campaign Career Development Awardees, becoming a Life Fellow on moving to the Institute of Cancer Research. He was appointed to the Chair of Biophysics at the Institute of Cancer Research in 1990, and moved to the new Chair of Chemical Biology at the School of Pharmacy in the University of London in 2002, where he also directs the Cancer Research UK Biomolecular Structure Group. He is currently Chairman of the Chemical Biology Forum of the Royal Society of Chemistry, which is involved in developing the interface between chemistry and the life sciences. He will shortly assume the Directorship of the newly-established Centre for Cancer Medicines at the School. Stephen Neidle has received several awards for his work on drug-nucleic acid recognition and drug design, including the 2000 prize of the Biological and Medicinal Chemistry Sector of the Royal Society of Chemistry, and its 2002 Interdisciplinary Award. He was the 2004 Paul Ehrlich Lecturer of the French Societé de Chimie Therapeutique, and was recently awarded the 2004 Aventis Prize in Medicinal Chemistry.

“the oblivion of subject” in philosophy and exactness at the present time: from Protagoras to the theory of chaos

OpenAIRE

Milan TASIĆ

2015-01-01

Socrates Protagoras' dilemma: the subjective or objective truth about the world, and ourselves, historically, has been ''resolved'' in favor of the ''knowledge as a necessary and general one'' (Socrates), and whose typical expression in our time is, for example, ''theory of everything'' (Einstein et al.), on which Stephen Hawking will say that it begins to speak of what God had in mind when creating the world. But more than two millennia after Protagoras, Kant will find that in every knowledg...

Dal Big Bang ai buchi neri

CERN Document Server

Hawking, Stephen W

1988-01-01

"Che cosa sappiamo sull'universo, e come lo sappiamo? Da dove è venuto, e dove sta andando? L'universo ebbe un inizio e, in tal caso cosa c'era prima? Il tempo avrà mai una fine?" Con questi quesiti Stephen Hawking introduce il lettore in una straordinaria avventura: un'emozionante cavalcata nel tempo. L'espansione dell'universo, il principio di indeterminazione, le particelle elementari e le forze della natura, l'origine e la sorte dell'universo, l'unificazione della fisica sono le grandi tappe di questo viaggio indimenticabile. Ma oltre a riassumere le conoscenze tradizionali Hawking illustra le ultime teorie sulla fisica dei buchi neri, il principio antropico, la teoria dell'universo inflazionario, l'universo contenuto in una bolla. Il titolo viene ripubblicato in una nuova veste editoriale, con la copertina che per l'occasione è stata realizzata da Hennie Haworth.

A redefinition of Hawking temperature on the event horizon: Thermodynamical equilibrium

International Nuclear Information System (INIS)

Saha, Subhajit; Chakraborty, Subenoy

2012-01-01

In this Letter we have used the recently introduced redefined Hawking temperature on the event horizon and investigated whether the generalized second law of thermodynamics (GSLT) and thermodynamic equilibrium holds for both the event and the apparent horizons. Here we have considered FRW universe and examined the GSLT and thermodynamic equilibrium with three examples. Finally, we have concluded that from the thermodynamic viewpoint, the universe bounded by the event horizon is more realistic than that by the apparent horizon at least for some examples.

STS-93 M.S. Stephen Hawley in the White Room

Science.gov (United States)

1999-01-01

STS-93 Mission Specialist Stephen A. Hawley (Ph.D.) is checked out by white room closeout crew members before entering the orbiter Columbia. In the background is Mission Specialist Michel Tognini of France, waiting to enter Columbia. The white room is an environmental chamber at the end of the orbiter access arm that provides entry to the orbiter crew compartment. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. After Space Shuttle Columbia's July 20 and 22 launch attempts were scrubbed, the launch was again rescheduled for Friday, July 23, at 12:24 a.m. EDT. The target landing date is July 27 at 11:20 p.m. EDT.

Habitat Effects on the Breeding Performance of Three Forest-Dwelling Hawks.

Science.gov (United States)

Björklund, Heidi; Valkama, Jari; Tomppo, Erkki; Laaksonen, Toni

2015-01-01

Habitat loss causes population declines, but the mechanisms are rarely known. In the European Boreal Zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. We studied the boreal breeding habitat and habitat-associated breeding performance of the northern goshawk (Accipiter gentilis), common buzzard (Buteo buteo) and European honey buzzard (Pernis apivorus). We combined long-term Finnish bird-of-prey data with multi-source national forest inventory data at various distances (100-4000 m) around the hawk nests. We found that breeding success of the goshawk was best explained by the habitat within a 2000-m radius around the nests; breeding was more successful with increasing proportions of old spruce forest and water, and decreasing proportions of young thinning forest. None of the habitat variables affected significantly the breeding success of the common buzzard or the honey buzzard, or the brood size of any of the species. The amount of old spruce forest decreased both around goshawk and common buzzard nests and throughout southern Finland in 1992-2010. In contrast, the area of young forest increased in southern Finland but not around hawk nests. We emphasize the importance of studying habitats at several spatial and temporal scales to determine the relevant species-specific scale and to detect environmental changes. Further effort is needed to reconcile the socioeconomic and ecological functions of forests and habitat requirements of old forest specialists.

Vagrant western red-shouldered hawks: origins, natal dispersal patterns, and survival

Science.gov (United States)

Bloom, Peter H.; Scott, J. Michael; Papp, Joseph M.; Thomas, Scott E.; Kidd, Jeff W.

2011-01-01

We report the results of a 40-year study of the western Red-shouldered Hawk (Buteo lineatus elegans) involving the banding of 2742 nestlings in southern California from 1970 to 2009 (this study) plus 127 nestlings banded in other California studies (1956–2008) and the analyses of 119 records of subsequent recovery from the Bird Banding Laboratory (1957–2009). Of the Red-shouldered Hawks recovered, 109 (91.6%) moved 100 km (long-distance dispersers). Three (2.5%), all long-distance dispersers, were vagrants (recovered outside the species' range of residency), and were found 374 to 843 km northeast and south of their banding locations in the Mojave, Great Basin, and Vizcaino deserts. The distribution of directions of short-distance dispersal was bipolar, closely corresponding with the northwest—southeast orientation of the species' range in southern California, while that of long-distance dispersers was mainly to the north. One of 10 long-distance dispersers, a nonvagrant, survived well into the age of breeding (103.0 months), whereas eight of the other nine perished before 14.5 months. The implications of vagrancy for conservation of this resident subspecies are that a relatively small source area can contribute genetic material over a vastly larger receiving area but rarely does so because of high mortality rates. Nonetheless, the movements of vagrants we documented provide evidence for the species' potential to populate new landscapes in response to changing environmental conditions and to maintain genetic heterogeneity within existing populations.

Habitat Effects on the Breeding Performance of Three Forest-Dwelling Hawks.

Directory of Open Access Journals (Sweden)

Heidi Björklund

Full Text Available Habitat loss causes population declines, but the mechanisms are rarely known. In the European Boreal Zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. We studied the boreal breeding habitat and habitat-associated breeding performance of the northern goshawk (Accipiter gentilis, common buzzard (Buteo buteo and European honey buzzard (Pernis apivorus. We combined long-term Finnish bird-of-prey data with multi-source national forest inventory data at various distances (100-4000 m around the hawk nests. We found that breeding success of the goshawk was best explained by the habitat within a 2000-m radius around the nests; breeding was more successful with increasing proportions of old spruce forest and water, and decreasing proportions of young thinning forest. None of the habitat variables affected significantly the breeding success of the common buzzard or the honey buzzard, or the brood size of any of the species. The amount of old spruce forest decreased both around goshawk and common buzzard nests and throughout southern Finland in 1992-2010. In contrast, the area of young forest increased in southern Finland but not around hawk nests. We emphasize the importance of studying habitats at several spatial and temporal scales to determine the relevant species-specific scale and to detect environmental changes. Further effort is needed to reconcile the socioeconomic and ecological functions of forests and habitat requirements of old forest specialists.

Entropy vs. Action in the (2+1)-Dimensional Hartle-Hawking Wave Function

OpenAIRE

Carlip, Steven

1992-01-01

In most attempts to compute the Hartle-Hawking ``wave function of the universe'' in Euclidean quantum gravity, two important approximations are made: the path integral is evaluated in a saddle point approximation, and only the leading (least action) extremum is taken into account. In (2+1)-dimensional gravity with a negative cosmological constant, the second assumption is shown to lead to incorrect results: although the leading extremum gives the most important single contribution to the path...

Globalization, Edu-Business and Network Governance: The Policy Sociology of Stephen J. Ball and Rethinking Education Policy Analysis

Science.gov (United States)

Lingard, Bob; Sellar, Sam

2013-01-01

This paper traces developments across Stephen J. Ball's policy sociology in education "oeuvre" and considers their implications for doing research on education policy today. It begins with an account of his policy sociology trilogy from the 1990s, which outlined his conception of the policy cycle consisting of the contexts of influence,…

Science, Intelligence, and Educational Policy: The Mismeasure of Frankenstein (with Apologies to Mary Shelley and Stephen Jay Gould).

Science.gov (United States)

Zappardino, Pamela

Stephen Jay Gould points out in "The Mismeasure of Man" (1981), "Science, since people must do it, is a socially embedded activity. It progresses by hunch, vision, and intuition." The legacy of the traditional construct of intelligence and its measurement through intelligence quotient (IQ) tests has not been educational improvement. Its legacy in…

HURRICANE AND SEVERE STORM SENTINEL (HS3) GLOBAL HAWK ADVANCED VERTICAL ATMOSPHERIC PROFILING SYSTEM (AVAPS) DROPSONDE SYSTEM V2

Data.gov (United States)

National Aeronautics and Space Administration — The Hurricane and Severe Storm Sentinel (HS3) Global Hawk Advanced Vertical Atmospheric Profiling System (AVAPS) Dropsonde System dataset was collected by the...

Anomalies, effective action and Hawking temperatures of a Schwarzschild black hole in the isotropic coordinates

International Nuclear Information System (INIS)

Wu Shuangqing; Peng Junjin; Zhao Zhanyue

2008-01-01

Motivated by the universality of Hawking radiation and that of the anomaly cancellation technique as well as the effective action method, we investigate the Hawking radiation of a Schwarzschild black hole in the isotropic coordinates via the cancellation of gravitational anomaly. After performing a dimensional reduction from the four-dimensional isotropic Schwarzschild metric, we show that this reduction procedure will, in general, result in two classes of two-dimensional effective metrics: the conformal equivalent and the inequivalent ones. For the physically equivalent class, the two-dimensional effective metric displays such a distinct feature that the determinant is not equal to the unity √(-g)≠1, but also vanishes at the horizon, the latter of which possibly invalidates the anomaly analysis there. Nevertheless, in this paper we adopt the effective action method to prove that the consistent energy-momentum tensor T r t is divergent on the horizon but √(-g)T t r remains finite there. Meanwhile, through an explicit calculation we show that the covariant energy-momentum tensor T-tilde t r equals zero at the horizon. Therefore the validity of the covariant regularity condition that demands that T-tilde t r = 0 at the horizon has been justified, indicating that the gravitational anomaly analysis can be safely extrapolated to the case where the metric determinant vanishes at the horizon. It is then demonstrated that for the physically equivalent reduced metric, both methods can give the correct Hawking temperature of the isotropic Schwarzschild black hole, while for the inequivalent one with the determinant √(-g) = 1 it can only give half of the correct temperature. We further exclude the latter undesired result by taking into account the general covariance of the energy-momentum tensor under the isotropic coordinate transformation

Aspects of quantum field theory in curved space-time

International Nuclear Information System (INIS)

Fulling, S.A.

1989-01-01

The theory of quantum fields on curved spacetimes has attracted great attention since the discovery, by Stephen Hawking, of black-hole evaporation. It remains an important subject for the understanding of such contemporary topics as inflationary cosmology, quantum gravity and superstring theory. The topics covered include normal-mode expansions for a general elliptic operator, Fock space, the Casimir effect, the Klein 'paradox', particle definition and particle creation in expanding universes, asymptotic expansion of Green's functions and heat kernels, and renormalization of the stress tensor. (author)

Finite upper bound for the Hawking decay time of an arbitrarily large black hole in anti-de Sitter spacetime

Science.gov (United States)

Page, Don N.

2018-01-01

In an asymptotically flat spacetime of dimension d >3 and with the Newtonian gravitational constant G , a spherical black hole of initial horizon radius rh and mass M ˜rhd -3/G has a total decay time to Hawking emission of td˜rhd -1/G ˜G2 /(d -3 )M(d -1 )/(d -3 ) which grows without bound as the radius rh and mass M are taken to infinity. However, in asymptotically anti-de Sitter spacetime with a length scale ℓ and with absorbing boundary conditions at infinity, the total Hawking decay time does not diverge as the mass and radius go to infinity but instead remains bounded by a time of the order of ℓd-1/G .

Mineral resources of the Hawk Mountain Wilderness Study Area, Honey County, Oregon

International Nuclear Information System (INIS)

Turrin, B.D.; Conrad, J.E.; Plouff, D.; King, H.D.; Swischer, C.C.; Mayerle, R.T.; Rains, R.L.

1989-01-01

The Hawk Mountain Wildeness Study Area in south-central Oregon is underlain by Miocene age basalt, welded tuff, and interbedded sedimentary rock. The western part of this study area has a low mineral resource potential for gold. There is a low mineral resource potential for small deposits of uranium in the sedimentary rocks. This entire study area has a low potential for geothermal and oil and gas resources. There are no mineral claims or identified resources in this study area

Return to work after vocational rehabilitation: does mindfulness matter?

Directory of Open Access Journals (Sweden)

Vindholmen S

2014-02-01

Full Text Available Solveig Vindholmen,1 Rune Høigaard,2 Geir Arild Espnes,3 Stephen Seiler41Department of Psychosocial Health, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway; 2Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway; 3Research Centre for Health Promotion and Resources, Department of Social Work and Health Science, Norwegian University of Science and Technology, Trondheim, Norway; 4Faculty of Health and Sport Sciences, University of Agder, Kristiansand, NorwayPurpose: Mindfulness has become an important construct in return-to-work (RTW rehabilitation. The aim of this study was to investigate whether mindfulness is a predictor for RTW, and to examine the indirect effect of mindfulness on RTW and work ability through quality of life (QOL.Methods: A retrospective study was conducted among 80 former participants (71 females and seven males from age 24 to 66, in a multidisciplinary vocational rehabilitation program (MVRP. Self-report questionnaires were used to measure work status, work ability, QOL, and mindfulness. Demographic data were also collected.Results: In the current sample, 47% of participants reported having returned to ordinary work. The majority of the non-working sub-sample reported being in work-related activity or education. A bias-corrected bootstrapping technique was used to examine indirect effects. Results revealed that mindfulness was indirectly related to both RTW and work ability through QOL. There was no significant total effect of mindfulness on work ability or RTW. Logistic regression analysis was performed to assess the impact of mindfulness on the likelihood that respondents returned to work. None of the independent mindfulness variables (observe, describe, act aware, non-judge, non-react made a unique statistically significant contribution to the model. The covariates work ability and education level significantly

Extremal Black Holes in Supergravity and the Bekenstein-Hawking Entropy

Directory of Open Access Journals (Sweden)

R. D'Auria

2002-03-01

Full Text Available Abstract: We review some results on the connection among supergravity central charges, BPS states and Bekenstein-Hawking entropy. In particular, N = 2 super-gravity in four dimensions is studied in detail. For higher N supergravities we just give an account of the general theory specializing the discussion to the N = 8 case when one half of supersymmetry is preserved. We stress the fact that for extremal supergravity black holes the entropy formula is topological, that is the entropy turns out to be a moduli independent quantity and can be written in terms of invariants of the duality group of the supergravity theory.

Kas postsovetlik kultuurikontekst on veel moes? / Hannaliisa Uusma, Terje Toomistu, Stephen Amico, Yngvar Steinholt ; intervjueerinud Maarja Merivoo-Parro

Index Scriptorium Estoniae

2017-01-01

Maarja Merivoo-Parroga vestlesid tänapäevastest muusikauuringutest sotsioloog ja muusikateadlane Hannaliisa Uusma, peagi esilinastuva Nõukogude hipiliikumist kaardistava dokumentaalfilmi režissöör ja etnoloogiadoktorant Terje Toomistu, ameeriklasest etnomusikoloogiadoktor Stephen Amico Bergeni ülikoolist ning norra pungiuurija, Tromsø ülikooli vene keele ja kirjanduse doktor Yngvar Steinholt. Neid kõiki paeluvad sooküsimused

Virginia Driving Hawk Sneve, Sioux Author. With Teacher's Guide. Native Americans of the Twentieth Century.

Science.gov (United States)

Minneapolis Public Schools, MN.

A biography for elementary school students describes the life and career of Virginia Driving Hawk Sneve (Sioux), a Native American free-lance writer, and includes her photograph and a map of South Dakota reservations. A story by Mrs. Sneve tells about a half-Sioux boy who confronts his heritage when his grandfather makes a long journey between his…

STS-95 Payload Specialist Glenn and his wife pose before their return flight to JSC

Science.gov (United States)

1998-01-01

At the Skid Strip at Cape Canaveral Air Station, STS-95 Payload Specialist John H. Glenn Jr., a senator from Ohio and one of the original seven Project Mercury astronauts, poses with his wife Annie before their return flight to the Johnson Space Center in Houston, Texas. The STS-95 mission ended with landing at Kennedy Space Center's Shuttle Landing Facility at 12:04 p.m. EST on Nov. 7. The STS-95 crew also includes Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialist Scott E. Parazynski; Mission Specialist Stephen K. Robinson; Mission Specialist Pedro Duque, with the European Space Agency (ESA); and Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA). The mission included research payloads such as the Spartan-201 solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as a SPACEHAB single module with experiments on space flight and the aging process.

The genus Alphitobius Stephens (Coleoptera, Tenebrionidae, Alphitobiini in Africa and adjacent islands

Directory of Open Access Journals (Sweden)

Wolfgang Schawaller

2014-06-01

Full Text Available All species of the genus Alphitobius Stephens, 1829 (Alphitobiini Reitter, 1917, subfamily Tenebrioninae Latreille, 1802 from Africa and adjacent islands are revised. New species: Alphitobius capitaneus sp. n. from Kenya. New synonyms: Cryptops ulomoides Solier, 1851, syn. n. of Alphitobius diaperinus (Panzer, 1796; Alphitobius rufus Ardoin, 1976, syn. n. of Alphitobius hobohmi Koch, 1953; Peltoides (Micropeltoides crypticoides Pic, 1916, syn. n. of Peltoides (Micropeltoides opacus (Gerstaecker, 1871, comb. n. Homonym: Alphitobius ulomoides Koch, 1953 = Alphitobius arnoldi nom. n. New combinations from Alphitobius: Ulomoides basilewskyi (Ardoin, 1969, comb. n.; Peltoides (Micropeltoides opacus (Gerstaecker, 1871, comb. n. Figures of all examined species are added and a species key is compiled.

The Greek charter of the Hungarian King Stephen I

Directory of Open Access Journals (Sweden)

Stojkovski Boris

2016-01-01

Full Text Available The first Hungarian Christian ruler, King Stephen I (997-1038 issued several charters that have survived to this day. One of them is the charter issued on behalf of the nuns from the Monastery of the Holy Theotokos in Veszprémvölgy. The charter was written in the Greek language, and has been the subject of many studies. The original has not been preserved; what remains is a copy from the time of King Coloman, dated to 1109. The charter has not been published in a critical edition in any language other than Hungarian and even though it has been examined by numerous Hungarian scholars, many questions remain open. The aim of the author is to provide a critical edition and an English translation of the charter, but also to clarify some remaining doubts about the charter and its contents. Furthermore, some comparisons will be made with the Byzantine charters issued at the beginning of the 11th and during the 12th century.

"The Power of the Oral Tradition: Giving Life to Words:" Conversations with Virginia Driving Hawk Sneve

Science.gov (United States)

Young, Teresa; Henderson, Darwin L.

2013-01-01

Virginia Driving Hawk Sneve, a former English teacher and school counselor, is an award-winning author, best known for her children's books about the Rosebud Sioux life and culture, which combines history and legend to create culturally rich and authentic Native American stories. In this article, the authors share their conversations with Virginia…

Evaluation of the effects of dorsal versus lateral recumbency on the cardiopulmonary system during anesthesia with isoflurane in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Hawkins, Michelle G; Malka, Shachar; Pascoe, Peter J; Solano, Adrian M; Kass, Philip H; Ohmura, Hajime; Jones, James H

2013-01-01

To evaluate the effects of dorsal versus lateral recumbency on the cardiopulmonary system during isoflurane anesthesia in red-tailed hawks (Buteo jamaicensis). 6 adult 1.1- to 1.6-kg red-tailed hawks. A randomized, crossover study was used to evaluate changes in respiratory rate, tidal volume, minute ventilation, heart rate, mean arterial and indirect blood pressures, and end-tidal Pco(2) measured every 5 minutes plus Paco(2) and Pao(2) and arterial pH measured every 15 minutes throughout a 75-minute study period. Respiratory rate was higher, tidal volume lower, and minute ventilation not different in lateral versus dorsal recumbency. Position did not affect heart rate, mean arterial blood pressure, or indirect blood pressure, although heart rate decreased during the anesthetic period. Birds hypoventilated in both positions and Paco(2) differed with time and position × time interaction. The Petco(2) position × time interaction was significant and Petco(2) was a mean of 7 Torr higher than Paco(2). The Paco(2) in dorsal recumbency was a mean of 32 Torr higher than in lateral recumbency. Birds in both positions developed respiratory acidosis. Differences in tidal volume with similar minute ventilation suggested red-tailed hawks in dorsal recumbency might have lower dead space ventilation. Despite similar minute ventilation in both positions, birds in dorsal recumbency hypoventilated more yet maintained higher Pao(2), suggesting parabronchial ventilatory or pulmonary blood flow distribution changes with position. The results refute the hypothesis that dorsal recumbency compromises ventilation and O(2) transport more than lateral recumbency in red-tailed hawks.

Climbing performance of Harris' hawks (Parabuteo unicinctus) with added load: Implications for muscle mechanics and for radiotracking

Science.gov (United States)

Pennycuick, C.J.; Fuller, M.R.; McAllister, L.

1989-01-01

Two Harris' hawks were trained to fly along horizontal and climbing flight paths, while carrying loads of various masses, to provide data for estimating available muscle power during short flights. The body mass of both hawks was about 920 g, and they were able to carry loads up to 630 g in horizontal flight. The rate of climb decreased with increasing all-up mass, as also did the climbing power (product of weight and rate of climb). Various assumptions about the aerodynamic power in low-speed climbs led to estimates of the maximum power output of the flight muscles ranging from 41 to 46 W. This, in turn, would imply a stress during shortening of around 210 kPa. The effects of a radio package on a bird that is raising young should be considered in relation to the food load that the forager can normally carry, rather than in relation to its body mass.

NASA Global Hawk Project Update and Future Plans: A New Tool for Earth Science Research

Science.gov (United States)

Naftel, Chris

2009-01-01

Science objectives include: First demonstration of the Global Hawk unmanned aircraft system (UAS) for NASA and NOAA Earth science research and applications; Validation of instruments on-board the Aura satellite; Exploration of trace gases, aerosols, and dynamics of remote upper Troposphere/lower Stratosphere regions; Sample polar vortex fragments and atmospheric rivers; Risk reduction for future missions that will study hurricanes and atmospheric rivers.

Generalized Laws of Black Hole Thermodynamics and Quantum Conservation Laws on Hawking Radiation Process

OpenAIRE

Wu, S. Q.; Cai, X.

2000-01-01

Four classical laws of black hole thermodynamics are extended from exterior (event) horizon to interior (Cauchy) horizon. Especially, the first law of classical thermodynamics for Kerr-Newman black hole (KNBH) is generalized to those in quantum form. Then five quantum conservation laws on the KNBH evaporation effect are derived in virtue of thermodynamical equilibrium conditions. As a by-product, Bekenstein-Hawking's relation $ S=A/4 $ is exactly recovered.

High prevalence of Sarcocystis calchasi sporocysts in European Accipiter hawks.

Science.gov (United States)

Olias, Philipp; Olias, Lena; Krücken, Jürgen; Lierz, Michael; Gruber, Achim D

2011-02-10

The emerging Sarcocystis calchasi induces a severe and lethal central nervous disease in its intermediate host, the domestic pigeon (Columba livia f. domestica). Experimental studies have identified the Northern goshawk (Accipiter g. gentilis) as final host. Phylogenetically closely related European sparrowhawks (Accipiter n. nisus) and wood pigeons (Columba palumbus) have been found to harbor genetically closely related Sarcocystis spp. However, data on the prevalence and potential interspecies occurrence of these parasites are lacking. Here, we report that European Accipiter hawks (Accipitrinae) are highly infected with S. calchasi, S. columbae and Sarcocystis sp. ex A. nisus in their small intestine. Thirty-one of 50 (62%) Northern goshawks necropsied during 1997-2008 were positive for S. calchasi in a newly established species-specific semi-nested PCR assay based on the first internal transcribed spacer region. Unexpectedly, 14 of 20 (71.4%) European sparrowhawks tested also positive. In addition, birds of both species were found to be infested with S. columbae and an, as yet, unnamed Sarcocystis sp. recently isolated from European sparrowhawks. These findings raise new questions about the host specificity of S. calchasi and its high virulence in domestic pigeons, since sparrowhawks only rarely prey on pigeons. Notably, isolated sporocysts from both infected Accipiter spp. measured 8 μm × 11.9 μm, precluding a preliminary identification of S. calchasi in feces of Accipiter hawks based on morphology alone. Importantly, three of four Northern goshawks used in falconry tested positive for S. calchasi. In conclusion, the results indicate that both European Accipter spp. in Germany serve as natural final hosts of S. calchasi and suggest that falconry and pigeon sport may serve as risk factors for the spread of this pathogen in domestic pigeons. Copyright © 2010 Elsevier B.V. All rights reserved.

Vision and foraging in cormorants: more like herons than hawks?

Directory of Open Access Journals (Sweden)

Craig R White

Full Text Available BACKGROUND: Great cormorants (Phalacrocorax carbo L. show the highest known foraging yield for a marine predator and they are often perceived to be in conflict with human economic interests. They are generally regarded as visually-guided, pursuit-dive foragers, so it would be expected that cormorants have excellent vision much like aerial predators, such as hawks which detect and pursue prey from a distance. Indeed cormorant eyes appear to show some specific adaptations to the amphibious life style. They are reported to have a highly pliable lens and powerful intraocular muscles which are thought to accommodate for the loss of corneal refractive power that accompanies immersion and ensures a well focussed image on the retina. However, nothing is known of the visual performance of these birds and how this might influence their prey capture technique. METHODOLOGY/PRINCIPAL FINDINGS: We measured the aquatic visual acuity of great cormorants under a range of viewing conditions (illuminance, target contrast, viewing distance and found it to be unexpectedly poor. Cormorant visual acuity under a range of viewing conditions is in fact comparable to unaided humans under water, and very inferior to that of aerial predators. We present a prey detectability model based upon the known acuity of cormorants at different illuminances, target contrasts and viewing distances. This shows that cormorants are able to detect individual prey only at close range (less than 1 m. CONCLUSIONS/SIGNIFICANCE: We conclude that cormorants are not the aquatic equivalent of hawks. Their efficient hunting involves the use of specialised foraging techniques which employ brief short-distance pursuit and/or rapid neck extension to capture prey that is visually detected or flushed only at short range. This technique appears to be driven proximately by the cormorant's limited visual capacities, and is analogous to the foraging techniques employed by herons.

"This will be our little secret" - Lukemisen dynamiikka Stephen Chboskyn kirjeromaanissa The Perks of Being a Wallflower

OpenAIRE

Tenkula, Jenni

2016-01-01

Tutkielmani käsittelee lukemisen dynamiikkaa ja tulkinnan rakentumisprosessia Stephen Chboskyn romaanissa The Perks of Being a Wallflower (1999). Tutkielmassa selvitän, miten lukijan tulkintaprosessi rakentuu teosta ensikertaa lukiessa. Lukija määrittyy retorisen kertomusteorian teoreetikkojen Peter J. Rabinowitzin ja James Phelanin tekijän tarkoittamaksi yleisöksi. Rakennan tekijän tarkoittaman yleisön tulkinnan lukemisen dynamiikan ja juonellisen progression kautta. Teoksen loppuratkaisu, p...

A Critique of Stephen Downes' "Learning Objects": A Chinese perspective

Directory of Open Access Journals (Sweden)

Fuhua (Oscar Lin

2001-07-01

Full Text Available This paper by Stephen Downes recommends a way of sharing online teaching/ course materials to accelerate course development and make education more cost-effective. His paper is a review of basic information about learning objects (LOs and includes examples that illustrate such technical terms as XML and TML. His paper, however, does not identify several important issues such as: a the level of granularity of learning objects; b selection and integration of learning objects in an appropriate way to form higher level units of study; c training of professors in the use of learning objects; d appropriate use of metadata to facilitate composition of higher level units; and e the potential of computer agents to facilitate the dynamic composition of personalized lessons. An unorganized aggregate of learning objects simply does not constitute a course. In order to create a properly designed final course, student and instructor interaction must be built in.

Who Invented the Word Asteroid: William Herschel or Stephen Weston?

Science.gov (United States)

Cunningham, Clifford J.; Orchiston, Wayne

2011-11-01

William Herschel made the first serious study of 1 Ceres and 2 Pallas in the year 1802. He was moved by their dissimilarities to the other planets to coin a new term to distinguish them. For this purpose he enlisted the aid of his good friends William Watson and Sir Joseph Banks. Watson gave him a long list of possible names, which Herschel rejected. With a lifetime of experience classifying and naming newly found objects in nature, Banks became the man both Erasmus Darwin (in 1781) and William Herschel (in 1802) turned to for sage advice in developing a new descriptive language. In the case of Ceres and Pallas, Banks turned the task over to his friend, the noted philologist Stephen Weston, FRS. It has recently been stated by a noted British historian that it was Weston - not Herschel - who coined the term 'asteroid' to collectively describe Ceres and Pallas. This claim is investigated, and parallels are drawn in the use of neologism in astronomy and botany.

The illustrated A brief history of time

CERN Document Server

Hawking, Stephen

1996-01-01

This is Stephen Hawking's updated, expanded and illustrated edition of his celebrated work which includes the most recent developments in the field, many of which were forecast by him. At the same time, he explains his complex theories through a fresh visual dimension. Over one hunded and fifty stunning colour illustrations have been specially commissioned for this purpose to help the reader understand what have become popular mythic images of our century, but which nonetheless remain difficult, abstract ideas to grasp. It includes a new introduction written specially for this edition.

Aspects of quantum field theory in curved space-time

Energy Technology Data Exchange (ETDEWEB)

Fulling, S.A. (Texas A and M Univ., College Station, TX (USA). Dept. of Mathematics)

1989-01-01

The theory of quantum fields on curved spacetimes has attracted great attention since the discovery, by Stephen Hawking, of black-hole evaporation. It remains an important subject for the understanding of such contemporary topics as inflationary cosmology, quantum gravity and superstring theory. The topics covered include normal-mode expansions for a general elliptic operator, Fock space, the Casimir effect, the Klein 'paradox', particle definition and particle creation in expanding universes, asymptotic expansion of Green's functions and heat kernels, and renormalization of the stress tensor. (author).

Hawking radiation screening and Penrose process shielding in the Kerr black hole

Energy Technology Data Exchange (ETDEWEB)

Mc Caughey, Eamon [Dublin Institute of Technology, School of Mathematical Sciences, Dublin 8 (Ireland)

2016-04-15

The radial motion of massive particles in the equatorial plane of a Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both inside and outside the ergosphere) and their effect on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient determined. (orig.)

Momentum correlations as signature of sonic Hawking radiation in Bose-Einstein condensates

Directory of Open Access Journals (Sweden)

A. Fabbri, N. Pavloff

2018-04-01

Full Text Available We study the two-body momentum correlation signal in a quasi one dimensional Bose-Einstein condensate in the presence of a sonic horizon. We identify the relevant correlation lines in momentum space and compute the intensity of the corresponding signal. We consider a set of different experimental procedures and identify the specific issues of each measuring process. We show that some inter-channel correlations, in particular the Hawking quantum-partner one, are particularly well adapted for witnessing quantum non-separability, being resilient to the effects of temperature and/or quantum quenches.

Comprehensive study of endurance for IAR-99 Hawk

Directory of Open Access Journals (Sweden)

Dorin LOZICI-BRINZEI

2014-03-01

Full Text Available The paper presents some methods of on-ground and in-flight calibration for strain gauges, intended to the development of complex programs which analyze the endurance phenomena for aerospace structures, with direct application to the IAR-99 Hawk. The strain gauges have the advantage of being sensitive to load and therefore to aerodynamic phenomena, thereby providing indications of the loads supported by the structure. The effects size of loads type phenomena caused by wind gusts or buffet can be measured only by strain gauges or accelerometres70 and they cannot be recorded by flight or fatigue parameters counters. The installation of a strain gauge is made using a pattern (its position and orientation are crucial and the strain gauge selected for installation should not be fragile or unstable. Routines should be established for periodic inspection of strain gauges and those which are defective should be replaced immediately.

Gauge theory description of D-brane black holes: emergence of the effective SCFT and Hawking radiation

International Nuclear Information System (INIS)

Hassan, S.F.; Wadia, S.R.

1998-02-01

We study the hypermultiplet moduli space of an N=4, U(Q 1 ) x U(Q 5 ) gauge theory in 1 + 1 dimensions to extract the effective SCFT description of near extremal 5-dimensional black holes modelled by a collection D1- and D5-branes. On the moduli space, excitations with fractional momenta arise due to a residual discrete gauge invariance. It is argued that, in the infra-red, the lowest energy excitations are described by an effective c = 6, N = 4 SCFT on T 4 , also valid in the large black hole regime. The ''effective string tension'' is obtained using T-duality covariance. While at the microscopic level, minimal scalars do not couple to (1,5) strings, in the effective theory a coupling is induced by (1,1) and (5,5) strings, leading to Hawking radiation. These considerations imply that, at least for such black holes, the calculation of the Hawking decay rate for minimal scalars has a sound foundation in string theory and statistical mechanics and, hence, there is no information loss. (author)

One Hair Postulate for Hawking Radiation as Tunneling Process

International Nuclear Information System (INIS)

Dong Hui; Sun Chang-Pu; Cai Qing-Yu; Liu Xu-Feng

2014-01-01

For Hawking radiation, treated as a tunneling process, the no-hair theorem of black hole together with the law of energy conservation is utilized to postulate that the tunneling rate only depends on the external qualities (e.g., the mass for the Schwarzschild black hole) and the energy of the radiated particle. This postulate is justified by the WKB approximation for calculating the tunneling probability. Based on this postulate, a general formula for the tunneling probability is derived without referring to the concrete form of black hole metric. This formula implies an intrinsic correlation between the successive processes of the black hole radiation of two or more particles. It also suggests a kind of entropy conservation and thus resolves the puzzle of black hole information loss in some sense. (general)

"Validity" and "liceity" in conjugal acts: A reply to Stephen Napier on the HIV-condom debate.

Science.gov (United States)

Arias, Joseph

2016-08-01

Stephen Napier has argued against the soundness of what he calls the "Canon-Law argument" against the moral permissibility of a couple employing a condom for the sake of one spouse avoiding the contraction of HIV from the other spouse. Without an attempt to provide a full defense of the Canon-Law argument per se, this paper argues that Napier has not shown that argument to be inadequate. Napier's critique of that argument suffers from unsubstantiated counterexamples and from a failure to take into account analogous senses of "procreative end" in reference to the conjugal act. Using magisterial documents and canonical sources, this paper suggests that the distinction between validity and liceity can be usefully applied to conjugal acts. Lay Summary: Stephen Napier has argued in favor of the claim that there is no plausible argument for thinking that married couples who use a condom in order to prevent HIV transmission are necessarily doing something morally wrong. In responding to Napier by showing that his arguments in favor of his claim are inconclusive, this article introduces a distinction, frequently used in sacramental theology, between validity and liceity (lawfulness) and applies this distinction to marital actions. I argue that some modifications to martial actions make them merely unlawful, whereas other modifications-such as using an intact condom-make them both unlawful and "invalid."

Pre-Hawking radiation may allow for reconstruction of the mass distribution of the collapsing object

Energy Technology Data Exchange (ETDEWEB)

Dai, De-Chang, E-mail: diedachung@gmail.com [Institute of Natural Sciences, Shanghai Key Lab for Particle Physics and Cosmology, and Center for Astrophysics and Astronomy, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Stojkovic, Dejan [HEPCOS, Department of Physics, SUNY, University at Buffalo, Buffalo, NY 14260-1500 (United States)

2016-07-10

Hawking radiation explicitly depends only on the black hole's total mass, charge and angular momentum. It is therefore generally believed that one cannot reconstruct the information about the initial mass distribution of an object that made the black hole. However, instead of looking at radiation from a static black hole, we can study the whole time-dependent process of the gravitational collapse, and pre-Hawking radiation which is excited because of the time-dependent metric. We compare radiation emitted by a single collapsing shell with that emitted by two concentric shells of the equivalent total mass. We calculate the gravitational trajectory and the momentum energy tensor. We show that the flux of energy emitted during the collapse by a single shell is significantly different from the flux emitted by two concentric shells of the equivalent total mass. When the static black hole is formed, the fluxes become indistinguishable. This implies that an observer studying the flux of particles from a collapsing object could in principle reconstruct information not only about the total mass of the collapsing object, but also about the mass distribution.

Pre-Hawking radiation may allow for reconstruction of the mass distribution of the collapsing object

Directory of Open Access Journals (Sweden)

De-Chang Dai

2016-07-01

Full Text Available Hawking radiation explicitly depends only on the black hole's total mass, charge and angular momentum. It is therefore generally believed that one cannot reconstruct the information about the initial mass distribution of an object that made the black hole. However, instead of looking at radiation from a static black hole, we can study the whole time-dependent process of the gravitational collapse, and pre-Hawking radiation which is excited because of the time-dependent metric. We compare radiation emitted by a single collapsing shell with that emitted by two concentric shells of the equivalent total mass. We calculate the gravitational trajectory and the momentum energy tensor. We show that the flux of energy emitted during the collapse by a single shell is significantly different from the flux emitted by two concentric shells of the equivalent total mass. When the static black hole is formed, the fluxes become indistinguishable. This implies that an observer studying the flux of particles from a collapsing object could in principle reconstruct information not only about the total mass of the collapsing object, but also about the mass distribution.

Survival rates and lifetime reproduction of breeding male Cooper’s Hawks in Wisconsin, 1980-2005

Science.gov (United States)

Rosenfield, Robert N.; Bielefeldt, John; Rosenfield, Laura J.; Booms, Travis L.; Bozek, Michael A.

2009-01-01

There are few published data on annual survival and no reports of lifetime reproduction for breeding Cooper's Hawks (Accipiter cooperii). Breeding males (n  =  105) in central and southeastern Wisconsin had an annual mortality rate of 19%, or a survival rate of 81% for birds ≤10 years of age. We did not detect significant differences in mortality rates between urban and rural habitats, nor between the earlier 13 years and later 13 years of this study. Male Cooper's Hawks produced from zero to 32 nestlings during their lifetimes. Body mass or size appeared unrelated to annual survivorship and lifetime reproduction, although lifetime reproduction was correlated strongly with longevity of breeding males. Fifteen of 66 males (23%) produced most (53%) of the nestlings. Our studies occurred in an area where breeding populations may be increasing with some of the highest reported productivity indices and nesting densities for this species. Habitat used for nesting on our Wisconsin study areas may be less important for survivorship and lifetime reproduction than acquisition of a nesting area in which a male will breed throughout his life.

Dynamics of flexural gravity waves: from sea ice to Hawking radiation and analogue gravity.

Science.gov (United States)

Das, S; Sahoo, T; Meylan, M H

2018-01-01

The propagation of flexural gravity waves, routinely used to model wave interaction with sea ice, is studied, including the effect of compression and current. A number of significant and surprising properties are shown to exist. The occurrence of blocking above a critical value of compression is illustrated. This is analogous to propagation of surface gravity waves in the presence of opposing current and light wave propagation in the curved space-time near a black hole, therefore providing a novel system for studying analogue gravity. Between the blocking and buckling limit of the compressive force, the dispersion relation possesses three positive real roots, contrary to an earlier observation of having a single positive real root. Negative energy waves, in which the phase and group velocity point in opposite directions, are also shown to exist. In the presence of an opposing current and certain critical ranges of compressive force, the second blocking point shifts from the positive to the negative branch of the dispersion relation. Such a shift is known as the Hawking effect from the analogous behaviour in the theory of relativity which leads to Hawking radiation. The theory we develop is illustrated with simulations of linear waves in the time domain.

De Cambridge a Brighton: Poesia Concreta na Grã-Bretanha, uma entrevista com Stephen Bann

OpenAIRE

Montero - University of the Arts, Gustavo Grandal; Albertoni (trad.) - University of the Arts London, Fernanda

2016-01-01

Extensa entrevista com o historiador da arte, curador e poeta concreto Stephen Bann, realizada por Gustavo Grandal Montero, concentrando-se em seu trabalho curatorial, crítico e artístico da década de 1960, em que esteve intimamente envolvido com o desenvolvimento da poesia concreta no Reino Unido. Bann associou-se precocemente com Ian Hamilton Finlay, co-organizou a Primeira exposição internacional de poesia concreta e cinética (Cambridge, 1964) e foi o curador da Exposição de Poesia Concret...

MIL SPEC 28 Square Foot Fire Burnback and Extinguishment Testing of FireAde, FlameOut II and Hawk ALLFIRE

National Research Council Canada - National Science Library

Barrett, Kimberly D; Kalberer, Jennifer L

2008-01-01

... for hydrocarbon fuel fires. This report documents the evaluation performed on the fire extinguishing agents FireAde 2000 AFFF LP, FlameOut II and Hawk ALLFORE in accordance with the parameters set forth in Military Specification ( MIL SPEC...

Roy Ellen, Stephen J. Lycett, Sarah E. Johns, eds., 2013, Understanding Cultural Transmission in Anthropology: A Critical Synthesis New York and Oxford: Berghahn Books

Directory of Open Access Journals (Sweden)

Clelia Viecelli

2015-10-01

Full Text Available recensione: Roy Ellen, Stephen J. Lycett, Sarah E. Johns, eds., 2013, Understanding Cultural Transmission in Anthropology: A Critical Synthesis New York and Oxford: Berghahn Books di Clelia Viecelli

Charge–mass ratio bound and optimization in the Parikh–Wilczek tunneling model of Hawking radiation

International Nuclear Information System (INIS)

Kim, Kyung Kiu; Wen, Wen-Yu

2014-01-01

In this Letter, we study the mutual information hidden in the Parikh–Wilczek tunneling model of Hawking radiation for Reissner–Nordström black holes. We argue that the condition of nonnegativity of mutual information suggests bound(s) for charge–mass ratio of emitted particles. We further view the radiation as an optimization process and discuss its effect on time evolution of a charged black hole.

The STS-95 crew poses with a Mercury capsule model before returning to JSC

Science.gov (United States)

1998-01-01

Before returning to the Johnson Space Center in Houston, Texas, members of the STS-95 crew pose with a model of a Mercury capsule following a media briefing at the Kennedy Space Center Press Site Auditorium . From left to right are Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA); Pilot Steven W. Lindsey; Mission Commander Curtis L. Brown Jr.; Friendship 7; Payload Specialist John H. Glenn Jr., a senator from Ohio and one of the original seven Project Mercury astronauts; Mission Specialist Scott E. Parazynski; and Mission Specialist Pedro Duque, with the European Space Agency (ESA). Also on the crew is Mission Specialist and Payload Commander Stephen K. Robinson (not shown). The STS-95 mission ended with landing at Kennedy Space Center's Shuttle Landing Facility at 12:04 p.m. EST on Nov. 7. The mission included research payloads such as the Spartan-201 solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as a SPACEHAB single module with experiments on space flight and the aging process.

STS-95 Payload Specialist Glenn participates in a media briefing before returning to JSC

Science.gov (United States)

1998-01-01

STS-95 Payload Specialist John H. Glenn Jr., a senator from Ohio and one of the original seven Project Mercury astronauts, participates in a media briefing at the Kennedy Space Center Press Site Auditorium before returning to the Johnson Space Center in Houston, Texas. The STS-95 mission ended with landing at Kennedy Space Center's Shuttle Landing Facility at 12:04 p.m. EST on Nov. 7. Also participating in the briefing were the other STS-95 crew members: Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialist and Payload Commander Stephen K. Robinson; Mission Specialist Scott E. Parazynski; Mission Specialist Pedro Duque, with the European Space Agency (ESA); and Payload Specialist Chiaki Mukai, with the National Space Development Agency of Japan (NASDA). The mission included research payloads such as the Spartan-201 solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as a SPACEHAB single module with experiments on space flight and the aging process.

My brief history

CERN Document Server

Hawking, Stephen

2013-01-01

My Brief History recounts Stephen Hawking’s improbable journey, from his postwar London boyhood to his years of international acclaim and celebrity. Lavishly illustrated with rarely seen photographs, this concise, witty, and candid account introduces readers to a Hawking rarely glimpsed in previous books: the inquisitive schoolboy whose classmates nicknamed him Einstein; the jokester who once placed a bet with a colleague over the existence of a particular black hole; and the young husband and father struggling to gain a foothold in the world of physics and cosmology. Writing with characteristic humility and humor, Hawking opens up about the challenges that confronted him following his diagnosis of ALS at age twenty-one. Tracing his development as a thinker, he explains how the prospect of an early death urged him onward through numerous intellectual breakthroughs, and talks about the genesis of his masterpiece A Brief History of Time—one of the iconic books of the twentieth century.

Accipiter hawks (Accipitridae) confirmed as definitive hosts of Sarcocystis turdusi, Sarcocystis cornixi and Sarcocystis sp. ex Phalacrocorax carbo.

Science.gov (United States)

Mayr, Sylvia L; Maier, Kristina; Müller, Jana; Enderlein, Dirk; Gruber, Achim D; Lierz, Michael

2016-08-01

Sarcocystis is a large genus of protozoan parasites with complex heteroxenous life cycles. For many species, either the intermediate or the definitive host is still unknown. In this study, 116 Accipiter hawks (Eurasian sparrowhawks and northern goshawks) were investigated for the presence of Sarcocystis spp. in their intestinal tract or their faeces. To gain a wide distribution, samples were collected throughout Germany within 2 years. It was possible to detect Sarcocystis-like oocysts in 65 samples. Sequencing of the ITS region or species-specific PCR identified 33 samples as Sarcocystis turdusi/Sarcocystis sp. ex A. nisus (18), Sarcocystis calchasi (6), Sarcocystis columbae (3), Sarcocystis cornixi (3) and Sarcocystis sp. ex Phalacrocorax carbo (3). Besides the known infestation with S. columbae, S. sp. ex A. nisus and S. calchasi the Accipiter hawks were thereby confirmed as definitive host of S. turdusi, S. cornixi and S. sp. ex Phalacrocorax carbo for the first time.

Analytic solutions in the dyon black hole with a cosmic string: Scalar fields, Hawking radiation and energy flux

Energy Technology Data Exchange (ETDEWEB)

Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Silva, G.V., E-mail: gislainevs@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

2015-11-15

Charged massive scalar fields are considered in the gravitational and electromagnetic field produced by a dyonic black hole with a cosmic string along its axis of symmetry. Exact solutions of both angular and radial parts of the covariant Klein–Gordon equation in this background are obtained, and are given in terms of the confluent Heun functions. The role of the presence of the cosmic string in these solutions is showed up. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation spectrum and the energy flux. -- Highlights: •A cosmic string is introduced along the axis of symmetry of the dyonic black hole. •The covariant Klein–Gordon equation for a charged massive scalar field in this background is analyzed. •Both angular and radial parts are transformed to a confluent Heun equation. •The resulting Hawking radiation spectrum and the energy flux are obtained.

When did legong start? A reply to Stephen Davies

Directory of Open Access Journals (Sweden)

Adrian Vickers

2009-05-01

Full Text Available Stephen Davies has recently opened up new ways of looking at the history of Bali’s premier dance form, legong. He has argued that legong started in the late nineteenth century, more specifically after 1887, probably in 1889, and that it is primarily derived from a form which Balinese presently call andir. Davies’ article involves a substantial reconsideration of the canonical nature of certain dance forms in Bali. The evidence Davies used is largely oral history. What is missing from Davies’ account is evidence from closer to the time period, evidence that can allow us to fix the date of the origins of legong more closely, and also to understand precisely what its performative and musical associations and origins might be. This evidence is present in Balinese and Dutch-language sources, and while there are limitations to these sources, they certainly modify Davies’ thesis.

The Impact of Foreign Investment Restrictions on the Stock Returns of Oil Sands Companies

Directory of Open Access Journals (Sweden)

Eugene Beaulieu

2014-06-01

Full Text Available In December 2012, prompted by the proposed purchase of Nexen by the Chinese SOE CNOOC, the federal government announced revised guidelines for investments by state-owned enterprises (SOEs in the oil sands. Declaring the sale marked “the end of a trend and not the beginning of a trend,” Prime Minister Stephen Harper explained how the government would approach such decisions in the future, including placing the onus on foreign investors to demonstrate how deals would be of net benefit to Canada, as well as granting the industry minister the discretion to accept or deny proposed deals. Accounting for five per cent of Canadian GDP, $28 billion in government revenue and three per cent of all jobs nationwide, the oil sands are an integral component of Canada’s economy. The sector has long relied on foreign capital to finance projects, meaning that any move to deter outside investment could have profound consequences for the development of this critical economic asset. In this paper, the authors examine the impact of this policy change by measuring the stock returns of firms operating in the oil sands. Employing an event study analysis, they find empirical evidence that the government’s policy change has resulted in the material destruction of shareholder wealth, particularly in the case of the smaller oil companies. What is more, given the composition of the global oil industry has changed to one where SOEs dominate both reserves and production, is this a policy Canada can afford in the long term? “When we say that Canada is open for business, we do not mean that Canada is for sale to foreign governments.” - Prime Minister Stephen Harper, December 7, 2012 “…going forward, the [industry] minister will find the acquisition of control of a Canadian oil-sands business by a state-owned enterprise to be of net benefit, only in an exceptional circumstance.” - Prime Minister Stephen Harper, December 7, 2012 “A year after the new Investment

Observation of Noise Correlated by the Hawking Effect in a Water Tank.

Science.gov (United States)

Euvé, L-P; Michel, F; Parentani, R; Philbin, T G; Rousseaux, G

2016-09-16

We measured the power spectrum and two-point correlation function for the randomly fluctuating free surface on the downstream side of a stationary flow with a maximum Froude number F_{max}≈0.85 reached above a localized obstacle. On such a flow the scattering of incident long wavelength modes is analogous to that responsible for black hole radiation (the Hawking effect). Our measurements of the noise show a clear correlation between pairs of modes of opposite energies. We also measure the scattering coefficients by applying the same analysis of correlations to waves produced by a wave maker.

Declaration of the Javan hawk eagle Spizaetus bartelsi as Indonesia's National Rare Animal impedes conservation of the species

NARCIS (Netherlands)

Nijman, V.; Shepherd, C.R.; van Balen, S.

2009-01-01

The endangered Javan hawk eagle Spizaetus bartelsi is threatened in part by the illegal pet trade. In 1993 the species was declared Indonesia's National Rare/Precious Animal, by former President Soeharto. Trade in the species and keeping it as a pet are illegal. We consolidated data about the

SR-71 Pilot Stephen (Steve) D. Ishmael

Science.gov (United States)

1992-01-01

NASA research pilot Stephen D. Ishmael is pictured here in front of an SR-71 Blackbird on the ramp at the Dryden Flight Research Center, Edwards, California. Ishmael was one of two NASA research pilots assigned to the SR-71 high speed research program in the early 1990s at NASA's Dryden Flight Research Facility (redesignated the Dryden Flight Research Center in 1994), Edwards, California. Ishmael became a NASA research pilot in 1977. Data from the SR-71 program will be used to aid designers of future supersonic aircraft and propulsion systems. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and

Microstructure and cross-sectional shape of limb bones in Great Horned Owls and Red-tailed Hawks: how do these features relate to differences in flight and hunting behavior?

Science.gov (United States)

Marelli, Crystal A; Simons, Erin L R

2014-01-01

The Red-tailed Hawk and Great Horned Owl are two species of raptor that are similar in body size, diet, and habitat. Both species use their hindlimbs during hunting, but differ in foot morphology, how they approach and immobilize prey, and the average size of prey captured. They also differ in primary flight style: the Red-tailed Hawk uses static soaring and the Great Horned Owl uses flap-gliding. The objectives of this study were to characterize the microstructure and cross-sectional shape of limb bones of these species and examine the relationship with flight and hunting behaviors. The mid-shaft of six limb bones from six individuals of each species was sampled. The degree of bone laminarity (proportion of circular primary vascular canals) and cross-sectional geometric parameters were calculated. In both species, the humerus and femur exhibited features that suggest high resistance to torsional loading, whereas the tibiotarsus and phalanges had a shape more likely to resist compression and bending in a specific plane. The femur of the Red-tailed Hawk exhibited higher laminarity and larger polar moment of area than that of the Great Horned Owl. The tibiotarsus was more elliptical than that of the Great Horned Owl. The hawk approaches prey from a more horizontal axis, takes prey of greater mass, and is more likely to pursue prey on the ground, which could potentially be causing more torsional loads on the femur and bending loads on the tibiotarsus. In addition, differences in polar moment of area of the phalanges between the species could relate to differences in foot morphology or digit length. The humerus and ulna of the flap-gliding Great Horned Owl are more elliptical than the static soaring Red-tailed Hawk, a shape that may better resist the bending loads associated with a larger amount of flapping.