Behavioral ecology of the Swainson's Hawk (Buteo swainsoni) in Washington
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.
Bechard, Marc J.; Sarasola, José Hernán; Woodbridge, Brian
2006-01-01
We examined the fasting migration hypothesis for Swainson’s Hawks (Buteo swainsoni) by estimating the length, duration, and speed of the migration between North and South America and measuring changes in their body masses at various times throughout the year. We instrumented 34 adult Swainson’s Hawks with satellite radios on their breeding grounds in western North America to determine the duration, length, and speed of the migration. Migrating south at 188 km/day, it took Swainson’s Hawks 51 ...
Space Use by Swainson’s Hawk (Buteo swainsoni in the Natomas Basin, California
E. Fleishman
2016-04-01
Full Text Available We used satellite-based remote sensing to estimate home ranges for Swainson’s Hawk, a species listed as threatened in California (USA, on its breeding grounds in the Natomas Basin (northern Central Valley, California and to evaluate whether the species’ space-use intensity (statistically derived density of telemetry locations was associated with land cover, sex, reproductive success, or life stage of offspring. We differentiated seven classes of land cover—alfalfa, annually rotated irrigated crops, developed, grassland, orchard / vineyard, rice, and water. From 2011–2013, we fitted transmitters with global positioning systems to 23 adult Swainson’s Hawks. We recorded a minimum of six locations per day per bird from spring through early autumn of each year. We used a fixed, bivariate-normal kernel estimator to calculate a utilization distribution at 30-m resolution for each life stage of each individual within each year. We used a linear mixed model to estimate the associations between intensity of space use and land cover, sex, and reproductive status. The majority of adult Swainson’s Hawks traveled distances up to 8–10 km from the nest throughout the breeding season. Median seasonal home-range sizes in a given year ranged from 87–172 km2. The association between intensity of space use and grassland was 50–139% stronger, and the association between intensity of space use and alfalfa 23–59% stronger, than the associations between intensity of space use and any other land-cover type. Intensity of space use did not vary as a function of sex, reproductive status, or life stage. Given our results and additional knowledge of the species’ ecology, we suggest that reproductive success and, in turn, population-level recruitment may be associated equally if not more closely with availability of nesting sites than with the current distribution of land cover.
Buteo Nesting Ecology: Evaluating Nesting of Swainson’s Hawks in the Northern Great Plains
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. PMID:26327440
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.
Diabetes mellitus in a red-tailed hawk (Buteo jamaicensis).
Wallner-Pendleton, E A; Rogers, D; Epple, A
1993-09-01
An adult, free-living female red-tailed hawk (Buteo jamaicensis) with clinical signs of generalized weakness, polyuria, and polydipsia, was killed and necropsied. An ante mortem serum sample taken from the bird contained 54.3 mmole/1 glucose, and large amounts of glucose were found in the urine. At necropsy, the pancreas was small, pale pink with multiple, round, approximately 0.5 mm white foci. Light and electron microscopic examination of the pancreas revealed markedly vacuolated islet cells. Histochemical examination of the tissue showed that the vacuolated cells were beta-cells. This is the first report of spontaneously occurring diabetes mellitus in a raptor.
Atherosclerosis and ischemic cardiomyopathy in a captive, adult red-tailed hawk (Buteo jamaicensis).
Shrubsole-Cockwill, Alana; Wojnarowicz, Chris; Parker, Dennilyn
2008-09-01
An adult, male, captive red-tailed hawk (Buteo jamaicensis) of at least 19 years of age presented in dorsal recumbency. The hawk was nonresponsive, and despite initial supportive care, died shortly after presentation. Gross postmortem revealed no abnormal findings. Histologic examination demonstrated atherosclerosis and ischemic cardiomyopathy. This is the first reported case of atherosclerosis in a red-tailed hawk.
Chlamydiosis in a red-tailed hawk (Buteo jamaicensis).
Mirandé, L A; Howerth, E W; Poston, R P
1992-04-01
A red-tailed hawk (Buteo jamaicensis) with signs of respiratory distress and diarrhea was captured in the Manchac Wildlife Management Area, Louisiana (USA) and died the following day. At necropsy, the carcass was emaciated and there were splenomegaly, and fibrinous pericarditis, airsacculitis, and perihepatitis. Microscopically, there were fibrinous pericarditis and airsacculitis, myocardial necrosis, necrotizing hepatitis, splenic necrosis with reticuloendothelial cell hyperplasia, interstitial pneumonia and focal pancreatic necrosis. Intracytoplasmic chlamydial inclusion bodies were noticed in macrophages in the fibrinous exudate covering air sac and pericardium, and in spleen, liver, heart, lung, and pancreas. Schizonts compatible with a Sarcocystis sp.-like protozoon were present in the walls of air capillaries in the lung. A Chlamydia sp.-like organism was isolated in embryonating chicken eggs and cell culture and identified as C. psittaci with immunofluorescent staining.
Brachial plexus injury in two red-tailed hawks (Buteo jamaicensis).
Shell, L; Richards, M; Saunders, G
1993-01-01
Two red-tailed hawks (Buteo jamaicensis), found near Deltaville, Virginia (USA), were evaluated because of inability to use a wing. Results of needle electromyographic studies of the affected wing muscles in both hawks were compatible with denervation. On euthanasia, one hawk had extensive axon and myelin loss with multifocal perivascular lymphocytic inflammation of its brachial plexus and radial nerve. Demyelination and axon loss in the dorsal white matter of the spinal cord on the affected side also were found at the origin of the brachial plexus. The other hawk's wing had not returned to functional status > 2 yr after injury.
Caryospora uptoni and Frenkelia sp.-like coccidial infections in red-tailed hawks (Buteo borealis).
Lindsay, D S; Blagburn, B L
1989-07-01
The feces from 16 red-tailed hawks (Buteo borealis) were examined by fecal flotation for the presence of coccidial oocysts or sporocysts. Oocysts of Caryospora uptoni were found in five (31%), sporocysts of a Frenkelia sp.-like coccidium were found in eight (50%), and mixed infections with both species of coccidia were found in three (19%) red-tailed hawks. Neither oocysts nor sporocysts were found in six (38%) red-tailed hawks. Sexual stages of C. uptoni were found in the duodenum and jejunum of a naturally infected red-tailed hawk. Sexual stages were located in enterocytes on the distal three-fourths of the villi. This study shows that over 60% of red-tailed hawks may be passing coccidial oocysts/sporocysts in their feces and provides morphological information for diagnosing C. uptoni infections in histological sections.
Health evaluation of Galapagos Hawks (Buteo galapagoensis) on Santiago Island, Galapagos.
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.
Pace, L W; Chengappa, M M; Greer, S; Alderson, C
1987-10-01
Erysipelothrix rhusiopathiae was isolated from the spleen, liver, lung, heart, kidney, and skin of a red-tailed hawk (Buteo jamaicensis) which had a concurrent avian pox virus infection. The hawk had been housed on a farm with domestic turkeys, providing a possible source of the E. rhusiopathiae.
Upton, S J; McKown, R D
1992-01-01
Oral inoculation of prairie voles, Microtus ochrogaster, with coccidian sporocysts isolated from the feces of a red-tailed hawk, Buteo jamaicensis, in Kansas, USA, resulted in formation of Frenkelia microti (Apicomplexa: Sarcocystidae) tissue cysts in the brains of the voles. Five additional isolates of morphologically similar sporocysts collected from red-tailed hawks or other Buteo spp. in Kansas failed to result in detectable infections in rodents. These results are the first to verify that red-tailed hawks are natural definitive host in North America for F. microti.
Titus, K.; Fuller, M.R.; Stauffer, D.F.; Sauer, J.R.; Pendleton, Beth Giron; LeFranc, Maurice N.=; Moss, Mary Beth
1989-01-01
Red-tailed, red-shouldered, and broad-winged hawks nest throughout the 11 northeastern states, and red-tailed, red-shouldered, and rough-legged hawks winter in this region. Historical and present ranges of these species are similar, although red-shouldered and broad-winged hawk ranges now have more vacant patches at a local and regional level. Only the red-shouldered hawk is of special concern or officially listed as threatened by some state agencies. Analysis of Breeding Bird Survey (BBS) data indicated positive trends in counts of red-tailed hawks along the more developed Northeast corridor. No trends were found in analyses of BBS data for red-shouldered hawks in either more- or less-developed regions of the Northeast. Based on the BBS, we found a decreasing trend in counts of broad-winged hawks along the more-developed Northeast corridor, and an increasing trend in less-developed regions of the Northeast. Our analyses of Christmas Bird Count data indicated no trend in counts of red-shouldered nor rough-legged hawks, but an increase in counts of red-tailed hawks from 1962 to 1983. Many individuals believe that species such as the red-shouldered hawk are declining in the Northeast, but no trends were detected in our analyses.
Cardiomyopathy and right-sided congestive heart failure in a red-tailed hawk (Buteo jamaicensis).
Knafo, S Emmanuelle; Rapoport, Gregg; Williams, Jamie; Brainard, Benjamin; Driskell, Elizabeth; Uhl, Elizabeth; Crochik, Sonia; Divers, Stephen J
2011-03-01
A 15-year-old female red-tailed hawk (Buteo jamaicensis) was evaluated because of dyspnea, anorexia, and coelomic distension. Diagnostic imaging results confirmed severe coelomic effusion and revealed a markedly dilated right ventricle. The diagnosis was right-sided congestive heart failure. Results of measurements of vitamin E, selenium, lead, zinc, and cardiac troponin levels were normal or nondiagnostic. The hawk was treated with furosemide, antifungal and antimicrobial agents, and supplemental fluids and oxygen, but euthanasia was elected because of the poor prognosis and the practical difficulties associated with intensive case management. To our knowledge, this is the first described case of cardiomyopathy and congestive heart failure in a captive red-tailed hawk.
Long, P; Choi, G; Rehmel, R
1983-01-01
A captive, immature red-tailed hawk (Buteo jamaicensis) was presented with multiple long-bone fractures, a serum calcium of 7.9 mg/dl, and a history of being fed an all-meat diet. Gross and microscopic examinations of the parathyroid glands revealed marked glandular hypertrophy and the presence of interlacing cords and clusters of light chief cells and oxyphil cells in approximately equal numbers. Bone sections showed severe fibrous osteodystrophy. These findings support the observation that the oxyphil cell is a product of continued stimulation, and they suggest that hypocalcemia may be a stimulating factor.
Pansteatitis in a free-ranging red-tailed hawk (Buteo jamaicensis).
Wong, E; Mikaelian, I; Desnoyers, M; Fitzgerald, G
1999-12-01
A free-ranging juvenile female red-tailed hawk (Buteo jamaicensis) that was unable to fly was admitted to a rehabilitation center and died 1 day later. Hematology and serum chemistry abnormalities included moderate regenerative anemia, elevated creatine kinase, and hyperphosphatemia. Necropsy revealed a generalized steatitis, and histology showed a necrotizing and granulomatous pansteatitis with intralesional pigment compatible with ceroid. There was also moderate diffuse myodegeneration, mild multifocal cardiomyopathy, and mild multifocal hepatic necrosis. These changes and lesions resemble those caused by vitamin E deficiency in mammals and fish-eating birds.
Red-shouldered Hawk (Buteo lineatus) abundance and habitat in a reclaimed mine landscape
Balcerzak, M.J.; Wood, P.B.
2003-01-01
Fragmentation of the landscape by large-scale mining may affect Red-shouldered Hawk (Buteo lineatus) populations by reducing the amount of forested habitat available in a landscape and by creating fragmented forest parches surrounded by reclaimed mine lands. We examined habitat characteristics and relative abundance of Red-shouldered Hawks in reclaimed mine landscapes within four treatments: early-successional grassland habitat, mid-successional shrub/pole habitat, late-successional fragmented forest habitat, and late-successional intact forest habitat. We quantified microhabitat characteristics within an 11.3-m-radius plot centered on 156 vegetation plots throughout the four treatments. We surveyed 48 stations on and adjacent to three mines for Red-shouldered Hawks using standardized broadcast call techniques during February 2000-January 2001 and measured landscape characteristics within 1000-m buffer zones centered on each station from digitized aerial photographs. Mean abundance of Red-shouldered Hawks was significantly higher in the intact forest (x?? = 0.07 detections/ point, SE = 0.03) than the grassland (x?? = 0.01, SE = 0.01) treatment, but did not differ from the fragmented forest (x?? = 0.03, SE = 0.01) or shrub/pole (x?? = 0.03, SE = 0.01) treatments. Most microhabitat characteristics in both fragmented and intact forest differed from shrub/pole and grasslands. Amount of wetland was the most important characteristic determining presence of Red-shouldered Hawks in a forest-dominated landscape. More wetlands in the landscape may provide abundant amphibians and reptiles, which are important in the diet of Red-shouldered Hawks. ?? 2003 The Raptor Research Foundation, Inc.
Lindsay, D S; Blagburn, B L
1986-10-01
Oocysts of Caryospora uptoni n. sp. were described from the feces of red-tailed hawks, Buteo jamaicensis borealis. Sporulated oocysts were spherical or subspherical and measured 28.1 by 26.4 micron. The oocyst wall was composed of a yellowish outer layer and brownish inner layer and was about 1.5 micron thick. Neither micropyle, polar granules, nor oocyst residuum were present. A single, spherical sporocyst 18.2 by 17.9 micron was present; a Stieda body was absent. A spherical eccentrically located sporocyst residuum was present in many sporocysts, but it degenerated to form a dispersed granular residuum in other sporocysts. Eight randomly arranged sporozoites, 12.6 by 4.2 micron, were present in each sporocyst; they contained a centrally or slightly posteriorly located nucleus.
Murray, Maureen; Tseng, Florina
2008-03-01
Anticoagulant rodenticides inhibit the activation of vitamin K-ependent clotting factors, resulting in fatal hemorrhage. Nontarget species are exposed to these rodenticides primarily by direct consumption of baits or secondarily by consumption of poisoned prey. The diagnosis of anticoagulant rodenticide toxicosis is more challenging in birds than in mammals because of the limited availability of laboratory tests to evaluate avian coagulation. In addition, the presenting signs in birds may differ from those commonly seen in mammals. Treatment for acute blood loss and therapy with vitamin K1 can result in a favorable outcome in birds. This report describes the presenting signs, diagnosis, and successful treatment of a red-tailed hawk (Buteo jamaicensis) with secondary anticoagulant rodenticide toxicosis.
Parasite infections in nestling red-shouldered hawks (Buteo lineatus) in northeast Wisconsin.
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.
Fine structure of the pecten oculi of the red-tailed hawk (Buteo jamaicensis).
Braekevelt, C R
1991-12-01
The pecten oculi of the red-tailed hawk (Buteo jamaicensis) has been examined by light and electron microscopy. In this species the pecten is very large and of the pleated type. It consists of 17-18 accordion folds which are joined apically by a heavily pigmented bridge of tissue which holds the pecten in a fan-like shape, widest at its base. It is situated over the optic nerve head and extends into the vitreous. Within each fold are numerous capillaries, larger supply and drainage vessels and melanocytes. The capillaries are specialized and display extensive microfolds on both the luminal and abluminal borders. The endothelial cell bodies are thin with most organelles present in a paranuclear location. The capillaries are surrounded by thick fibrillar basal laminae which are probably structurally important and which often enclose pericytes. The melanocytes which are most plentiful in the bridge region and peripherally in the pecten, form an incomplete sheath around the capillaries and other blood vessels. These melanocytes are also felt to be fulfilling a structural role within the pecten. The morphology of the pecten of the red-tailed hawk is indicative of a heavy involvement in the transport of materials to the avascular avian retina.
Growing skull fracture in a red-tailed hawk (Buteo jamaicensis).
Rush, E Marie; Shores, Andrew; Meintel, Sarah; Hathcock, John T
2014-09-01
Growing skull fractures have been reported in humans for many years, usually resulting from injury to the soft skull during the rapid growth period of an infant's life. Nestling raptors have thin, fragile skulls, a rapid growth rate, and compete aggressively for food items. Skull trauma may occur, which may lead to the development of a growing skull fracture. Growing skull fractures may be under-diagnosed in raptor rehabilitation facilities that do not have access to advanced technologic equipment. Three-dimensional (3-D) computed tomography was used to diagnose a growing skull fracture in a red-tailed hawk (Buteo jamaicensis). The lesion was surgically repaired and the animal was eventually returned to the wild. This is the first report of a growing skull fracture in an animal. In this case, 3-D computed topographic imaging was utilized to diagnose a growing skull fracture in a red-tailed hawk, surgical repair was performed, and the bird recovered completely and was ultimately released.
Goldstein, Michael; Bechard, Marc J.; Parker, Melissa; Kochert, Michael N.; Lanusse, Agustín E.
2000-01-01
Observamos aguiluchos langosteros (Buteo swainsoni; Swainson's hawk) cerca de San Francisco de Córdoba, Argentina (310 30' S, 620 05' W) durante enero y febrero de 1997. Hicimos tres recorridos al noreste de Córdoba y al oeste de Santa Fé, el primero para reconocimiento del área, el segundo para localizar y capturar ejemplares, y el tercero para evaluar un incidente de mortandad. Los aguiluchos fueron abundantes (aproximadamente 3.500 aguiluchos en el primer viaje y 2.340 en el segundo viaje)...
Bloomfield, R B; Brooks, D; Vulliet, R
1997-03-01
The pharmacokinetic parameters of amikacin were determined in red-tailed hawks (Buteo jamaicensis) following the i.m. administration of a single 20 mg/kg dose. After a rapid absorption phase, mean amikacin serum concentrations peaked at 65 +/- 12 micrograms/ML 30-45 min following injection. The serum amikacin concentrations decreased to 2.3 +/- 2 micrograms/ml at 12 hr postinjection. Amikacin was eliminated with first-order kinetics characteristic of a single-compartment model with a half-life of 2.02 +/- 0.63 hr. The volume of distribution was estimated to be 0.28 +/- 0.03 L/kg. Forty-two isolates of gram-negative bacteria and coagulase-positive Staphylococcus species were cultured from birds of prey presented to the Veterinary Medical Teaching Hospital at the University of California-Davis. The minimum inhibitory concentration (MICs) of amikacin ranged from 0.5 to 8.0 micrograms/ml (mean = 2.5 micrograms/ml). The 20 mg/kg dose used in this study resulted in serum concentrations at or above the MICs for > 12 hr for most of the isolates examined. The heaviest birds had the lowest peak serum amikacin concentrations, and the lightest birds had the highest, despite exact volume replacement for each sample drawn. This observation suggests that doses should be based on factors other than weight alone. Amikacin administered at 15-20 mg/kg/day, either as a single dose or divided into two or three doses, is effective in treating sensitive pathogens of the red-tailed hawk.
Multifocal respiratory and vertebral mycobacteriosis in a red-tailed hawk (Buteo jamaicensis).
Sadar, Miranda J; McRuer, David; Hawkins, Michelle G; Armién, Aníbal G
2015-03-01
An adult, female, free-ranging red-tailed hawk (Buteo jamaicensis) was presented to a rehabilitation facility for an inability to stand. On examination, it displayed bilateral exaggeration of the pelvic limb reflexes with extensor muscle rigidity, intact superficial pain response, and positive withdrawal reflexes. A complete blood count identified moderate leukocytosis characterized by moderate heterophilia. No abnormalities were appreciable on radiographic evaluation. After initial improvement, it regressed and was euthanized 27 days after presentation. Necropsy and histologic investigation identified reduction in the diameter of the vertebral canal and spinal cord at cervical segments 8-9 with coalescing granulomas and intralesional acid-fast bacilli within the intertrabecular space, left side of the clavicular air sac, and cranial left lung. Bacterial culture and genetic sequencing from respiratory lesions identified Mycobacterium avium avium. Real time-polymerase chain reaction of paraffin-fixed spinal tissue tested positive for M. avium complex. Mycobacteriosis should be considered when peripheral neurologic deficits are present in raptors.
Retinal photoreceptor fine structure in the red-tailed hawk (Buteo jamaicensis).
Braekevelt, C R
1993-09-01
The retinal photoreceptors of the red-tailed hawk (Buteo jamaicensis) consist of rods, single cones and double (unequal) cones present in a ratio of about 2:1:5. In the light-adapted state, the rods are slender elongated cells with outer segments that reach to the retinal epithelial (RPE) cells. The inner segment displays an ellipsoid of mitochondria, plentiful polysomes, some rough ER and Golgi zones. The rod nucleus is located deep within the outer nuclear layer and the synaptic spherule displays both invaginated (ribbon) and superficial (conventional) synaptic sites. Single cones show a thin tapering outer segment, a large electron lucent oil droplet at the apex of the inner segment and an ellipsoid of mitochondria. Double cones consist of a larger chief member which displays a thin tapering outer segment and an electron dense oil droplet as well as a smaller accessory cone which shows no oil droplet, an ellipsoid and a paraboloid of glycogen. As in the single cone, polysomes, RER and Golgi zones are also noted in the inner segments of both members of the double cone. Near the external limiting membrane the chief and accessory cones show membrane specializations indicative of junctions on their contiguous surfaces. All cone photoreceptors are of a smaller diameter than is normally reported for avian species. Both single and double cones display several invaginated synapses as well as numerous superficial synaptic sites.
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.
Doss, Grayson A; Mans, Christoph
2016-06-01
Manual restraint in birds of prey is required for many veterinary and research procedures. To investigate the effects of handling stress on physiologic parameters in raptorial birds, 8 red-tailed hawks ( Buteo jamaicensis ) were manually restrained over a 15-minute period. Respiratory rate (RR), heart rate (HR), and cloacal temperature were monitored over time and recorded at defined intervals during the experiment. The effect of hooding on physiologic variables was also evaluated in a complete crossover design. Both RR and HR decreased significantly during the 15-minute restraint period (HR, -80 ± 101.4 beats/min [bpm], [P hawks, hooding versus nonhooding amplified the decrease in HR and RR but had no effect on stress-induced hyperthermia.
Bechert, Ursula; Christensen, J Mark; Poppenga, Robert; Fahmy, Sahar A; Redig, Patrick
2010-06-01
To determine pharmacokinetic parameters of orally administered terbinafine hydrochloride for potential treatment of aspergillosis in raptors, 10 adult red-tailed hawks (Buteo jamaicensis) were used in single dose trials by using 15, 30, and 60 mg/kg doses with a 2-week washout period between trials. After administration of 15 mg/kg terbinafine, mean (+/- SD) plasma concentration peaked in approximately 5 hours at 0.3 +/- 0.24 microg/mL, whereas a 30 mg/kg dose resulted in peak mean (+/- SD) plasma concentration of 1.2 +/- 0.40 microg/mL in 3 hours and a 60 mg/kg dose resulted in mean (+/- SD) concentration of 2.0 +/- 0.75 microg/mL in 5 hours. The volume of distribution decreased with increasing doses, averaging 76.8 +/- 38.06 mL/kg for the 15 mg/kg dose and falling to 55.2 +/- 17.4 mL/kg for the 30 mg/kg dose. This suggests that terbinafine accumulated in deep tissues, limiting further distribution at higher doses. The harmonic mean (+/- SD) half-life was biphasic, with initial values of 14.7 +/- 6.67 hours, 17.5 +/- 8.7 hours, and 13.3 +/- 5.03 hours for 15, 30, and 60 mg/kg doses, respectively. A rapid first-elimination phase was followed by a slower second phase, and final elimination was estimated to be 161 +/- 78.2 and 147 +/- 65.6 hours for 15 and 30 mg/kg doses, respectively. Linearity was demonstrated for the area under the curve but not for peak plasma concentrations for the 3 doses used. Calculations based on pharmacokinetic parameter values indicated that a dosage of 22 mg/kg terbinafine q24h would result in steady-state trough plasma concentrations above the minimum inhibitory concentration of terbinafine (0.8-1.6 microg/mL). This dosage is recommended as a potential treatment option for aspergillosis in raptors. However, additional research is required to determine both treatment efficacy and safety.
Robbins, P K; Tell, L A; Needham, M L; Craigmill, A L
2000-03-01
This study characterized and compared the pharmacokinetics of piperacillin after single 100 mg/kg i.m. injections in nine red-tailed hawks (Buteo jamaicensis) and five great horned owls (Bubo virginianus) over 48 hr by a modified agar well diffusion microbial inhibition assay. The mean maximum plasma piperacillin concentrations were 204 microg/ml and 221 microg/ml for the hawks and owls, respectively, and times of maximum concentrations were 15 min and 30 min, respectively. The calculated mean terminal elimination half-lives were 77 min in the hawks and 118 min in the owls. Area-under-the-curve values were 218 +/- 52 microg x hr/ml in the hawks and 444 +/- 104 microg x hr/ml in the owls. On the basis of the most common minimal inhibitory concentration (90%) for various bacterial isolates from clinical samples of 8 microg/ml, analysis of the data suggests that the maximum dosing interval for piperacillin at 100 mg/kg in medium sized raptors should be 4-6 hr.
Santos, A A; Da Silva, A Marques Joppert; Silva, M R Regis; Segreto, H R Cômodo; Egami, M Imoto
2003-10-01
In the peripheral blood of the roadside hawk, Buteo magnirostris, the following types of granulocytic leucocytes were identified: heterophil, eosinophil and basophil. The heterophils presented acidophilic and spindle shaped granules, the eosinophils possess spherical eosinophilic granules and the basophils showed spherical and basophilic granules. The heterophils and eosinophils presented positive cytochemical reaction to glycogen and basic polyaminoacid, while the eosinophils presented sudanophilic granules, which were also positive for myeloperoxidase. The heterophils, alone, presented positivity for acid phosphatase in some granules and immunoreactivity to TGF-beta1 was observed only in the cytoplasm of the eosinophils. Electron microscopy demonstrated the heterophil granules as predominantly spindle shaped, being strongly electron-dense, while the eosinophils had numerous uniformly electron-dense spherical granules and the basophils presented three different types of granules identified according to their electron-density and the aspect of their matrix.
Land cover associations of nesting territories of three sympatric buteos in shortgrass prairie
McConnell, S.; O'Connell, T. J.; Leslie, David M.
2008-01-01
Three species of Buteo hawks nest sympatrically in the southern Great Plains of the United States. Dietary overlap among them is broad and we tested the hypothesis these species partition their breeding habitat spatially. We compared land cover and topography around 224 nests of the three species breeding in shortgrass prairie in 2004 and 2005. Red-tailed Hawks (Buteo jamaicensis) nested almost exclusively in riparian timber surrounded by prairie (95% prairie land cover around nests) and disproportionately used areas with greater topographic relief within prairie landscapes. Swainson's Hawks (B. swainsoni) commonly nested in low-relief areas dominated by small-grain production agriculture but generally used habitats in proportion to availability. Most nest sites of Ferruginous Hawks (B. regalis) were in prairie (78% prairie land cover around nests), but some were in areas that were at least partially agricultural. Ferruginous Hawks had at least two times more sand sagebrush (Artemisia filifolia) around their nests than their two congeners. We conclude that sympatric breeding Buteos on the southern Great Plains spatially partitioned nest sites according to subtle differences in land cover and topography.
Parsley, Ruth A; Tell, Lisa A; Gehring, Ronette
2017-04-01
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 crossover study design, hawks were randomly assigned to first receive voriconazole (15 mg/kg, PO) injected into a dead mouse (n = 3; fed birds) or without food (4; unfed birds). Sixteen days later, treatments were reversed. Blood samples were collected at various points to measure plasma voriconazole concentrations by ultraperformance liquid chromatography. Pharmacokinetic data were analyzed by noncompartmental methods and fit to a compartmental model through nonlinear mixed-effects regression, with feeding status and body weight investigated as covariates. RESULTS Voriconazole was well absorbed, with quantifiable plasma concentrations up to 24 hours after administration. Mean plasma half-life was approximately 2 hours in fed and unfed birds. Administration of the voriconazole in food delayed absorption, resulting in a significant delay in time to maximum plasma concentration. The final compartmental model included a categorical covariate to account for this lag in absorption as well as body weight as a covariate of total body clearance (relative to unknown bioavailability). CONCLUSIONS AND CLINICAL RELEVANCE A single dose of voriconazole (15 mg/kg) administered PO to red-tailed hawks resulted in mean plasma voriconazole concentrations greater than the targeted value (1 μg/mL). Additional studies with larger sample sizes and multidose regimens are required before the model developed here can be applied in clinical settings.
Sander, Samantha; Whittington, Julia K; Bennett, Avery; Burgdorf-Moisuk, Anne; Mitchell, Mark A
2013-12-01
Pododermatitis is a pathologic condition commonly reported in captive raptors and characterized by swelling, excoriation, ulceration, cellulitis, or abscessation of the plantar aspect of the foot. Its cause can be multifactorial, often involving abnormal weight bearing or poor sanitation, and medical and surgical techniques, in addition to environmental alterations, are hallmarks of treatment. In this case, a single pedicle advancement flap was used to treat chronic, nonresponsive grade V/VII pododermatitis of the right metatarsal pad in a red-tailed hawk (Buteo jamaicensis). The advancement flap was formed by using the interdigital skin between digits 3 and 4. The double layer of skin was incised and separated, and the leading edge of the flap was then advanced over the defect and secured with simple interrupted subcutaneous and skin sutures. The foot was bandaged after surgery to take pressure off the surgical site. At 58 days after the surgery, the hawk was deemed medically sound with no signs of pododermatitis and was released to a wildlife rehabilitator. The use of a single pedicle advancement flap has not previously been reported for the treatment of pododermatitis.
Pain-Suppressed Behaviors in the Red-tailed Hawk 1 (Buteo jamaicensis).
Mazor-Thomas, Jana E; Mann, Phyllis E; Karas, Alicia Z; Tseng, Flo
2014-03-01
Our ability to provide analgesia in wild and exotic patients is hampered by a lack of species-specific information on effective drugs and protocols. One contributing factor is the difficulty of applying data from traditional laboratory tests of nociception to clinical conditions frequently involving combinations of inflammatory, mechanical, and neuropathic pain. Pain-suppressed behaviors have become a valuable predictor of clinical utility in other species; in this study we extend this framework to red -tailed hawks in a wildlife hospital, in an attempt to develop a new, humane testing method for birds of prey. We scored six behaviors in hawks hospitalized either for orthopedic trauma or for non-painful conditions. These behaviors included: movement about the cage, grooming, head motions, foot shifts, beak clacks, and rouse. Movement, head motions, and beak clacks were all significantly reduced in hawks with recent orthopedic injury, but not in hawks with healed or minor injuries (Pred -tailed hawks with recent orthopedic trauma show consistent and marked red uctions in several normal maintenance behaviors. Head movements, reported for the first time in this study as a potential marker of pain in birds, in particular seem to be insensitive to sedative side effects of buprenorphine, while being a sensitive measu re of affective state in hawks with painful injuries. These behaviors can be scored humanely and with minimal expense, and should be considered for further research on pain and analgesia in avian species.
Lumeij, J T; Sprang, E P; Redig, P T
1998-01-01
To investigate the usefulness of allopurinol for the treatment of hyperuricemia in birds, experimental studies were performed using the physiologically occurring post-prandial hyperuricaemia in birds of prey as a model. Pre-and post-prandial plasma concentrations of allopurinol, oxypurinol, xanthine, hypoxan-thine and uric acid were established by high performance liquid chromatography in red-tailed hawks (RTH, Buteo jamaicensis) at various time intervals after receiving allopurinol (50 mg/kg SID) or placebo. The dosage used caused slight, but significantly elevated plasma uric acid concentrations compared to controls, as well as vomiting in the majority of treated birds. Markedly elevated plasma concentrations of oxypurinol, xanthine and hypoxanthine were seen in experimental birds. Toxic signs were attributed to oxypurinol, the active (and toxic) metabolite of allopurinol. Xanthinuria was considered to be the cause of the observed renal function disorder. Extrapolation of data from studies in humans and combining these with those of the present study suggest that the maximum dose of allopurinol that can be safely administered to RTH is about half the dose given in the present study, but this needs verification.
Wünschmann, Arno; Shivers, Jan; Bender, Jeff; Carroll, Larry; Fuller, Susan; Saggese, Miguel; van Wettere, Arnaud; Redig, Pat
2004-09-01
Carcasses of 13 red-tailed hawks (RTHAs) and 11 Cooper's hawks (COHAs) were tested for West Nile virus (WNV) using WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR) on fresh brain tissue and WNV-specific immunohistochemistry (IHC) on various organs. Ten COHAs (91%) and 11 RTHAs (85%) were positive for WNV RNA by RT-PCR. All 11 COHAs (100%) and 10 RTHAs (77%) were positive for WNV antigen by IHC. A triad of inflammatory lesions, including chronic lymphoplasmacytic and histiocytic encephalitis, endophthalmitis, and myocarditis, was common in both species. In COHAs, the heart (54%), cerebrum (50%), and eye (45%) were the organs that most commonly contained WNV antigen. The amount of WNV antigen was usually small. In RTHAs, the kidney (38%), cerebrum (38%), cerebellum (38%), and eye (36%) were the organs most commonly containing WNV antigen. Unlike COHAs, larger amounts of WNV antigen were present in the cerebrum of RTHAs. WNV antigen was detected in similar cell populations in both species, including neurons of brain, spinal cord, and retina, pigmented epithelial cells of the retina, epithelial cells of renal medullary tubules, cardiomyocytes, endothelial cells and smooth muscle cells of arteries, dendritic cells of splenic lymph follicles, exocrine pancreatic cells, adrenal cells, and keratinocytes of the skin. The study presents strong evidence that WNV can cause a chronic fatal disease in RTHAs and COHAs. The lesion distribution of WNV infection in both species is variable, but inflammatory lesions are common, and a triad of lesions including encephalitis, myocarditis, and endophthalmitis is indicative of WNV infection in both species.
Ocular Lesions in Red-Tailed Hawks ( Buteo jamaicensis) With Naturally Acquired West Nile Disease.
Wünschmann, A; Armién, A G; Khatri, M; Martinez, L C; Willette, M; Glaser, A; Alvarez, J; Redig, P
2017-03-01
Ocular lesions are common in red-tailed hawks with West Nile (WN) disease. These lesions consist of pectenitis, choroidal or retinal inflammation, or retinal necrosis, but detailed investigation of the ocular lesions is lacking. Postmortem examination of the eyes of 16 red-tailed hawks with naturally acquired WN disease and 3 red-tailed hawks without WN disease was performed using histopathology, immunohistochemistry for West Nile virus (WNV) antigen, glial fibrillary acid protein, cleaved caspase-3, and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method. Retinal lesions were classified as type I or type II lesions. Type I lesions were characterized by lymphoplasmacytic infiltrates in the subjacent choroid with degeneration limited to the outer retina (type Ia lesion) or with degeneration and necrosis of the outer retina or outer and inner retina (type Ib lesion) while retinal collapse, atrophy, and scarring were hallmarks of type II lesions. Type II retinal lesions were associated with a more pronounced choroiditis. Although not statistically significant, WNV antigen tended to be present in larger quantity in type Ib lesions. Type I lesions are considered acute while type II lesions are chronic. The development of retinal lesions was associated with the presence of an inflammatory infiltrate in the choroid. A breakdown of the blood-retina barrier is suspected to be the main route of infection of the retina. Within the retina, virus appeared to spread via both neuronal and Müller cell processes.
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.
Gentry, Jordan; Montgerard, Christy; Crandall, Elizabeth; Cruz-Espindola, Crisanta; Boothe, Dawn; Bellah, Jamie
2014-09-01
Voriconazole is effective for treatment of aspergillosis, a common disease in captive red-tailed hawks ( Buteo jamaicensis ). To determine the disposition and safety of voriconazole after single and multiple, oral doses, 12 adult red-tailed hawks were studied in 2 phases. In phase 1, each bird received a single dose of voriconazole solution (10 mg/kg) by gavage. Blood samples were collected at 0, 0.5, 1, 3, 6, 9, 12, 16, 24, and 36 hours after treatment. In phase 2, each of 8 birds received voriconazole oral solution at 10 mg/kg PO q12h for 14 days. Plasma samples were collected on days 0, 5, and 10 and after the final dose and were processed as in phase 1. Plasma samples were submitted for analysis of voriconazole levels by high-performance liquid chromatography and ultraviolet spectrophotometry and for measurement of selected plasma biochemical parameters. After single dosing, voriconazole concentrations reached a (mean ± SD) peak (Cmax) of 4.7 ± 1.3 μg/mL at 2.0 ± 1.2 hours. The disappearance half-life (t1/2) was 2.8 ± 0.7 hours, and the mean residence time (MRT) was 4.6 ± 0.9 hours. After the last dose at 14 days, the mean Cmax of voriconazole was 4.5 ± 2.7 μg/mL at 2.4 ± 1.1 hours. The t1/2 was 2.1 ± 0.8 hours, and the MRT was 3.5 ± 1.1 hours. Although concentrations of several plasma biochemical parameters were significantly different at study end compared with prestudy concentrations, only plasma creatine kinase activity was outside the reference range. No adverse reactions were observed in any of the birds. After both single and multiple dosing at 10 mg/kg, voriconazole concentrations exceeded the minimum inhibitory concentration to inhibit 90% (MIC90) of Aspergillus species (1 μg/mL) by at least fourfold and remained above the MIC90 for 8.8 ± 1.1 hours after single dosing versus 6.5 ± 1.5 hours after multiple dosing (P = .003). This difference suggests that more frequent dosing (eg, up to q8h) may be necessary to maintain target
Coates, Peter S.; Howe, Kristy B.; Casazza, Michael L.; Delehanty, David J.
2014-01-01
A goal in avian ecology is to understand factors that influence differences in nesting habitat and distribution among species, especially within changing landscapes. Over the past 2 decades, humans have altered sagebrush ecosystems as a result of expansion in energy production and transmission. Our primary study objective was to identify differences in the use of landscape characteristics and natural and anthropogenic features by nesting Common Ravens (Corvus corax) and 3 species of buteo (Swainson's Hawk [Buteo swainsoni], Red-tailed Hawk [B. jamaicensis], and Ferruginous Hawk [B. regalis]) within a sagebrush ecosystem in southeastern Idaho. During 2007–2009, we measured multiple environmental factors associated with 212 nest sites using data collected remotely and in the field. We then developed multinomial models to predict nesting probabilities by each species and predictive response curves based on model-averaged estimates. We found differences among species related to nesting substrate (natural vs. anthropogenic), agriculture, native grassland, and edge (interface of 2 cover types). Most important, ravens had a higher probability of nesting on anthropogenic features (0.80) than the other 3 species (Artemisia spp.), favoring increased numbers of nesting ravens and fewer nesting Ferruginous Hawks. Our results indicate that habitat alterations, fragmentation, and forthcoming disturbances anticipated with continued energy development in sagebrush steppe ecosystems can lead to predictable changes in raptor and raven communities.
Poffers, J; Lumeij, J T; Timmermans-Sprang, E P M; Redig, P T
2002-12-01
The present paper reports the effects of allopurinol in a raptor hyperuricaemic model. The study was performed as a follow-up to previous experiments wherein allopurinol was used in doses of 100 and 50 mg/kg, and was proved to be toxic at these higher dose rates. To investigate whether 25 mg/kg (semel in die) s.i.d. allopurinol is a safe and effective dose in Red-tailed Hawks (Buteo jamaicensis) to reduce plasma uric acid concentrations, experimental studies were performed using the physiologically occurring postprandial hyperuricaemia. Preprandial and postprandial plasma concentrations of xanthine, hypoxanthine, allopurinol, oxypurinol and uric acid were established by high-performance liquid chromatography at various time intervals after receiving allopurinol (25 mg/kg SID) or placebo. No significant differences were observed between the experimental and the control group. These results indicate that this dose is safe to administer; however, this dose failed to cause a significant effect on plasma uric acid concentrations. Because of the low therapeutic ratio of allopurinol in Red-tailed Hawks, follow-up studies have concentrated on an alternative for the treatment of hyperuricaemia, namely urate oxidase.
Lemon, Matthew J; Pack, LeeAnn; Forzán, María J
2012-01-01
A free-ranging adult female red-tailed hawk died suddenly after 3 weeks in rehabilitation for a radial fracture. Cause of death was septic thrombosis from a chronic bacterial valvular endocarditis, probably associated with injury at the fracture site. The challenge of clinical diagnosis of sepsis in wild birds is emphasized.
2012-01-01
A free-ranging adult female red-tailed hawk died suddenly after 3 weeks in rehabilitation for a radial fracture. Cause of death was septic thrombosis from a chronic bacterial valvular endocarditis, probably associated with injury at the fracture site. The challenge of clinical diagnosis of sepsis in wild birds is emphasized.
Lacasse, Claude; Gamble, Kathryn C; Boothe, Dawn M
2013-09-01
Pharmacokinetic data were determined after a single dose of meloxicam in red-tailed hawks (RTH; Buteo jamaicensis) and great horned owls (GHO; Bubo virginianus). In a nonrandomized crossover design, individual birds of each species received 1 dose of intravenous meloxicam (0.5 mg/kg i.v.; n = 7 for each species) followed by a 2-week washout period, and then each received 1 dose of oral meloxicam (0.5 mg/kg PO; n = 5 for each species). Blood samples were collected intermittently after administration, and meloxicam was detected in plasma by high-performance liquid chromatography. Time versus plasma concentration data were subjected to noncompartmental analysis. Red-tailed hawks were determined to have the shortest elimination half-life for meloxicam (0.49 +/- 0.5 hours) of any species documented. Great horned owls also eliminated meloxicam very rapidly (0.78 +/- 0.52 hours). Great horned owls achieved higher plasma concentrations (368 +/- 87 ng/mL) of meloxicam than RTH (182 +/- 167 ng/mL) after oral administration, although RTH had a markedly higher volume of distribution (832 +/- 711 mL/kg) than GHO (137.6 +/- 62.7 mL/kg). The differences in meloxicam pharmacokinetics between these 2 raptor species supports the need for species-dependent studies and underlines the challenges of extrapolating drug dosages between species. Results of this study suggest that the current recommended once-daily dosing interval of oral meloxicam is unlikely to maintain plasma concentrations anticipated to be therapeutic in either RTH or GHO, and practical dosing options are questionable for this nonsteriodal anti-inflammatory drug in these raptor species.
Van Wettere, Arnaud J; Redig, Patrick T; Wallace, Larry J; Bourgeault, Craig A; Bechtold, Joan E
2009-12-01
Use of external skeletal fixator-intramedullary pin (ESF-IM) tie-in fixators is an adjustable and effective method of fracture fixation in birds. The objective of this study was to determine the contribution of each of the following parameters to the compressive and torsional rigidity of an ESF-IM pin tie-in applied to avian bones with an osteotomy gap: (1) varying the fixation pin position in the proximal bone segment and (2) increasing the number of fixation pins in one or both bone segments. ESF-IM pin tie-in constructs were applied to humeri harvested from red-tailed hawks (Buteo jamaicensis) (n=24) that had been euthanatized for clinical reasons. Constructs with a variation in the placement of the proximal fixation pin and with 2, 3, or 4 fixation pins applied to avian bone with an osteotomy gap were loaded to a defined displacement in torque and axial compression. Response variables were determined from resulting load-displacement curves (construct stiffness, load at 1-mm displacement). Increasing the number of fixation pins from 1 to 2 per bone segment significantly increased the stiffness in torque (110%) and compression (60%), and the safe load in torque (107%) and compression (50%). Adding a fixation pin to the distal bone segment to form a 3-pin fixator significantly increased the stiffness (27%) and safe load (20%) in torque but not in axial compression. In the configuration with 2 fixation pins, placing the proximal pin distally in the proximal bone segment significantly increased the stiffness in torque (28%), and the safe load in torque (23%) and in axial compression (32%). Results quantified the relative importance of specific parameters affecting the rigidity of ESF-IM pin tie-in constructs as applied to unstable bone fracture models in birds.
Heptachlor seed treatment contaminates hawks, owls, and eagles of Columbia Basin, Oregon
Henny, C.J.; Blus, L.J.; Kaiser, T.E.
1984-01-01
We evaluated organochlorine residues in 12 species of hawks. owls, and eagles from the Columbia Basin of Oregon between 1978 and 1981. Companion studies showed that heptachlor epoxide (HE) induced adult mortality and reduced productivity of the Canada Goose (Branta canadensis) and American Kestrel (Falco sparverius).ln this study, brain tissue from raptors found dead and sample eggs from 90 nests were analyzed for organochlorines. The primary concern was HE that entered raptor food chains through the ingestion of heptachlor-treated seed by their prey. HE residues were detected in eggs from 9 of 10 species and ranged as high as 4.75 ppm (wet wt), but no definite effects of HE on productivity were readily apparent from the limited series of nests. However, the hazard of heptachlor seed treatments to birds of prey was demonstrated by the occurrence of lethal residues of HE in brain tissue of 3 Golden Eagles (Aquila chrysaetos) and 1 Rough-legged Hawk (Buteo lagopus). Other organochlorine pesticides were present in the eggs and significant relationships were found between DDE and eggshell thickness for the Swainson's Hawk (Buteo swainsoni) and Western Screech-Owl (Otus kennicotti), although shell thinning (9.6% and 7.4%) was below the generally accepted range where reproductive problems have been known to occur.
78 FR 66058 - Habitat Conservation Plan for South Sacramento County, California
2013-11-04
...) Pallid bat (Antrozous pallidus) Western red bat (Lasiurus blossevillii) Yuma myotis bat (Myotis yumanensis) White-tailed kite (Elanus leucurus) Cooper's hawk (Accipiter cooperii) Ferruginous hawk (Buteo...) ] Northern harrier (Circus cyaneus) Swainson's hawk (Buteo swainsoni) Tricolored blackbird (Agelaius...
MIGRATION PATTERNS, USE OF STOPOVER AREAS, AND AUSTRAL SUMMER MOVEMENTS OF SWAINSON'S HAWKS.
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.
Nesting habitat and productivity of Swainson's Hawks in southeastern Arizona
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.
Duke, G E; Evanson, O A; Redig, P T
1976-11-01
Strain gage transducers were permanently implanted on the muscular stomachs of 13 turkeys, 3 great-horned owls and 2 red-tailed hawks to monitor gastric motility before, during and after eating. Following fasting, the sight of food resulted in significant increases in gastric contractile activity in all three species. Gastric motility further increased when the birds were allowed to eat. In raptors, however, a brief interruption in gastric motility occurred immediately after eating. This is apparently analogous to receptive relaxation which occurs in the stomach of mammals.
Bolette, David P
2007-02-01
Oligacanthorhynchus nickoli n. sp. (Acanthocephala: Oligacanthorhynchidae) is described from the great-horned owl, Bubo virginianus (Gmelin, 1788) (type host), and red-tailed hawk, Buteojamaicensis (Gmelin, 1788), collected in central Arizona. The new species is most similar to Oligacanthorhynchus iheringi and Oligacanthorhynchus minor, but it differs from all congeners primarily by trunk length, proboscis size and armature, egg size, geographical range, and host species. It is distinguished from the 9 Oligacanthorhynchus species occurring in avian hosts from both the Western and Eastern Hemispheres. Descriptions of juvenile forms of O. nickoli from the intestine of B. jamaicensis are provided from recently ingested cystacanths with everted proboscides.
Fatal pox infection in a rough-legged hawk
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.
Clark, William S; Galen, Spencer C; Hull, Joshua M; Mayo, Megan A; Witt, Christopher C
2017-01-01
An adult Buteo was found dead as a road-kill south of Sacramento, California, and was thought to represent the first state record of the eastern Red-shouldered Hawk (B. lineatus lineatus;). It is now a specimen in the Museum of Wildlife and Fisheries Biology (WFB 4816) at the University of California, Davis. We examined this specimen and found that many of its plumage characters differed from all other adult Red-shouldered Hawks examined, including nominate adults. Plumage markings and measurements were intermediate between Red-tailed Hawk (Buteo jamaicensis, ssp calurus) and Red-shouldered Hawk (ssp elegans), leading us to hypothesize that the bird was a hybrid. However, mtDNA sequences and nuDNA microsatellites proved definitively that the bird was a Red-shouldered Hawk, most likely of eastern origin. This case illustrates that apparent hybrids or apparent vagrants could be individuals with anomalous phenotypes caused by rare genetic variation or novel epigenetic effects.
US Fish and Wildlife Service, Department of the Interior — During our investigations along the Upper Mississippi River during 1999 we located Red-shouldered Hawks (Buteo lineatus) in a total of 32 of the 51 areas searched....
Recent trends in counts of migrant hawks from northeastern North America
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 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.
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.
Ferruginous hawks on the Yakima Training Center
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.
William S. Clark
2017-01-01
Full Text Available An adult Buteo was found dead as a road-kill south of Sacramento, California, and was thought to represent the first state record of the eastern Red-shouldered Hawk (B. lineatus lineatus;. It is now a specimen in the Museum of Wildlife and Fisheries Biology (WFB 4816 at the University of California, Davis. We examined this specimen and found that many of its plumage characters differed from all other adult Red-shouldered Hawks examined, including nominate adults. Plumage markings and measurements were intermediate between Red-tailed Hawk (Buteo jamaicensis, ssp calurus and Red-shouldered Hawk (ssp elegans, leading us to hypothesize that the bird was a hybrid. However, mtDNA sequences and nuDNA microsatellites proved definitively that the bird was a Red-shouldered Hawk, most likely of eastern origin. This case illustrates that apparent hybrids or apparent vagrants could be individuals with anomalous phenotypes caused by rare genetic variation or novel epigenetic effects.
Parentani, Renaud; Spindel, Philippe
2011-12-01
Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which escaping at infinity while the other is trapped inside the black hole horizon. It is named after the physicist Stephen Hawking who derived its existence in 1974. This radiation reduces the mass of black holes and is therefore also known as black hole evaporation.
Influence of poisoned prey on foraging behavior of ferruginous hawks
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.
Toxoplasma gondii infections in red-tailed hawks inoculated orally with tissue cysts.
Lindsay, D S; Dubey, J P; Blagburn, B L
1991-04-01
The response to inoculation of Toxoplasma gondii tissue cysts was examined in 3 red-tailed hawks (Buteo jamaicensis). One hawk (hawk 1) was inoculated orally with 3.000 tissue cysts of the GT-1 isolate of T. gondii and 2 hawks (hawks 2 and 3) each were inoculated orally with 12,000 tissue cysts of a mixture of 8 isolates of T. gondii. None of the hawks developed clinical signs of toxoplasmosis. Serum antibodies were measured with the modified direct agglutination test using formalin-fixed tachyzoites. Hawk 1 had a titer of 1:40 prior to inoculation and did not have an increase in titer during the study. Hawks 2 and 3 had titers of 1:5 and 1:10, respectively, prior to inoculation, and both had increased titers (titers greater than or equal to 1:60) by 1 wk postinoculation and remained T. gondii antibody positive throughout the 10 wk of the study. Toxoplasma gondii was isolated from the heart and breast muscle of hawk 1. The biologic behavior of this T. gondii isolate was different from the 1 inoculated, and it probably represents a prior natural infection. Toxoplasma gondii was isolated from the brain, heart, breast muscle, and a mixture of gizzard and proventriculus from hawk 2 and from breast muscle of hawk 3. Toxoplasma gondii was not isolated from the eye, lung, liver, kidney, or spleen of any red-tailed hawk.
TEZEL, Mehmet; GİRİŞGİN, Ahmet Onur; BİRLİK, SEZEN; YILDIRIMHAN, HİKMET SAMİ; ŞENLİK, Bayram
2015-01-01
Raptors can be parasitized by numerous helminth species due to their feeding behavior. When the parasite load is high, the bird's life can be affected. A total of 21 common buzzards, Buteo buteo, from different districts of Bursa, in Northwest Turkey, were examined for helminth infections. The results of the postmortem examination revealed that 15 of 21 buzzards (71.43%) harbored 1 or more helminth species. Seven species/genera of helminths were detected at the following prevalence r...
Nesting ecology and behavior of Broad-winged Hawks in moist karst forests of Puerto Rico
Hengstenberg, D.W.; Vilella, F.J.
2005-01-01
The Puerto Rican Broad-winged Hawk (Buteo platypterus brunnescens) is an endemic and endangered subspecies inhabiting upland montane forests of Puerto Rico. The reproductive ecology, behavior, and nesting habitat of the Broad-winged Hawk were studied in Ri??o Abajo Forest, Puerto Rico, from 2001-02. We observed 158 courtship displays by Broad-winged Hawks. Also, we recorded 25 territorial interactions between resident Broad-winged Hawks and intruding Red-tailed Hawks (Buteo jamaicensis jamaicensis). Broad-winged Hawks displaced intruding Red-tailed Hawks from occupied territories (P = 0.009). Mayfield nest survival was 0.67 across breeding seasons (0.81 in 2001, N = 6; 0.51 in 2002, N = 4), and pairs averaged 1.1 young per nest (years combined). The birds nested in mixed species timber plantations and mature secondary forest. Nests were placed in the upper reaches of large trees emerging from the canopy. Nest tree DBH, understory stem density, and distance to karst cliff wall correctly classified (77.8%) nest sites. ?? 2005 The Raptor Research Foundation, Inc.
Experimental vacuolar myelinopathy in red-tailed hawks.
Fischer, John R; Lewis-Weis, Lynn A; Tate, Cynthia M
2003-04-01
Avian vacuolar myelinopathy (AVM) was recognized in 1994 as a cause of wild bird mortality when 29 bald eagles (Haliaeetus leucocephalus) succumbed to the disease at DeGray Lake, Arkansas (USA). The cause of AVM and its source remain undetermined despite extensive diagnostic and research investigations. Two years later, when AVM killed 26 eagles in the same area in Arkansas, it became apparent that American coots (Fulica americana) had identical neurologic signs and lesions, and it was hypothesized that eagles acquired AVM via ingestion of affected coots. In order to test this hypothesis, we fed coot tissues (brain, liver, kidney, muscle, fat, and intestinal tract) to rehabilitated, non-releasable red-tailed hawks (Buteo jamaicensis). Five hawks received tissues from coots with AVM lesions, and one hawk received tissues from coots without brain lesions that had been collected at a site where AVM never has been documented. All hawks received 12-70 g/day (mean = 38 g) of coot tissues for 28 days. All six hawks remained clinically normal during the study. The birds were euthanatized on day 29 and microscopic lesions of AVM were found in all hawks that received tissues from affected coots, but not in the hawk that received tissues from unaffected coots. This marks the first time that AVM has been produced in birds under laboratory conditions and proves that birds of prey can acquire AVM via ingestion of tissues from affected coots.
Pest risk assessment of Dendroctonus valens, Hyphantria cunea and Apriona swainsoni in Beijing
LIU Haijun; LUO Youqing; WEN Junbao; ZHANG Zhiming; FENG Jihua; TAO Wanqiang
2006-01-01
According to the international methods of pest risk analysis and urban forestry characteristics in Beijing,a quantitative risk assessment system in Beijing for three primary non-indigenous pests was proposed.This system was used to analyze three major non-indigenous species,Dendroctonus valens,Hyphantria cunea,and Apriona swainsoni.The results show that the risks of these three pests in the Beijing area were 2.46,2.30,and 2.02,which were all highly risky.Based on the result and extensive risk communications,combined with the management experience of the Beijing Forest Protection Station,the authors proposed some effective control measures to prevent the invasion of the three pests into Beijing.
Duque Escobar, Gonzalo
2009-01-01
Obra y vida de este connotado físico, cosmólogo y científico nacido en Oxford y sucesor de la Cátedra Lucasiana en Cambridge, reconocido como el más famoso de los físicos teóricos vivos hoy por su "Breve historia del tiempo", y como una figura legendaria por sus aportes logrados al integrar en una teoría la Relatividad General y la Mecánica Cuántica. Este documento se basa en un resumen del libro “Stephen Hawking para principiantes”, de McEvoy y Zárate, con algunos complementos de la bibliogr...
Frenkelia sp.-like infection in the small intestine of a red-tailed hawk.
Lindsay, D S; Ambrus, S I; Blagburn, B L
1987-10-01
Developmental stages of a Frenkelia sp.-like coccidium were observed in tissue sections of the duodenum, jejunum, and ileum of a naturally infected red-tailed hawk (Buteo jamaicensis borealis) that died and was examined at necropsy. Developmental stages were located in the lamina propria of these tissues. Thirty sporulated sporocysts measured 11.1 X 8.1 microns in tissue sections. Four sporozoites were present in each sporulated sporocyst. The coccidial infection was not a contributing factor in the death of this red-tailed hawk.
Actkinson, M.A.; Kuvlesky, W.P.; Boal, C.W.; Brennan, L.A.; Hernandez, F.
2007-01-01
We quantified nesting-site habitats for sympatric White-tailed Hawks (Buteo albicaudatus) (n = 40), Red-tailed Hawks (B. jamaicensis) (n = 39), and Crested Caracaras (Caracara cheriway) (n = 24) in the Coastal Sand Plain of south Texas. White-tailed Hawks and Crested Caracara nest sites occurred in savannas, whereas Red-tailed Hawk nest sites occurred in woodlands on the edge of savannas. White-tailed Hawk nest sites were in shrubs and trees that were shorter (3.5 ?? 1.0 m) and had smaller canopy diameters (5.5 ?? 2.1 m) than those of Red-tailed Hawks (10.1 ?? 2.0 m, 13.7 ?? 5.8 m) and Crested Caracaras (5.6 ?? 1.7 m, 8.5 ?? 3.5 m). Red-tailed Hawk nest sites had higher woody densities (15.7 ?? 9.6 plants) and more woody cover (84 ?? 19%) than those of White-tailed Hawks (5.6 ?? 5.8 plants, 20 ?? 21%) and Crested Caracaras (9.9 ?? 6.7 plants, 55 ?? 34%). Crested Caracara nest sites were in dense, multi-branched shrubs composed of more living material (97 ?? 3%) than those of White-tailed (88 ?? 18%) and Red-tailed hawks (88 ?? 18%). Nest sites of White-tailed Hawks, Red-tailed Hawks, and Crested Caracaras were similar to random samples from the surrounding habitat indicating that preferred nesting habitat was available for each of these species at least within 60 m of active nest sites. Nest tree height, along with woody plant and native grass cover best discriminated nest sites among the three raptor species. There was no overlap at Red-tailed and White-tailed hawk nest sites in vegetation structure, while Crested Caracara nests were in habitat intermediate between the two other species. Partitioning of nesting habitat may be how these raptor species co-exist at the broader landscape scale of our study area in the Coastal Sand Plain of Texas.
Battaglia, Alessandra; Ghidini, Sergio; Campanini, Giorgio; Spaggiari, Roberto
2005-01-01
In this study, two raptor species, the common buzzard (Buteo buteo) and the little owl (Athene noctua), were investigated for lead and cadmium concentrations, using liver, kidneys, pectoral muscle, sternum bone, and feathers. All the collected birds died at the Centro Recupero Rapaci of Lega Italiana Protezione Uccelli in Sala Baganza (Parma, Italy). They arrived alive at the Centro between November 1998 and November 1999 but died or were put to death as a consequence of injuries or other ailments. The results of the investigation do not show an excessive exposure to cadmium, whereas some interesting data have emerged in the case of lead. The concentration of the latter in the liver and in the bone of two little owls seem to suggest the possibility of chronic exposure. The high values found in one common buzzard, on the other hand, suggest an acute exposure and, probably, a case of lead shot ingestion.
Castell, Stephen
2012-06-01
In the wake of Stephen Hawking's appearance on the TV show The Big Bang Theory, last month's "Quanta" page (May p3), included a request: "If you think Hawking should appear in any other TV shows, then let us know".
Red-shouldered hawk nesting habitat preference in south Texas
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.
Landscape-related variation in the diet composition of the common buzzard (Buteo buteo in Belarus
Sidorovich Anna A.
2016-12-01
Full Text Available We examined common buzzard (Buteo buteo feeding patterns in landscapes with different habitat structure in Belarus. A total of 561 pellets and prey remains were sampled in 1998-2012 from which 1065 prey and other food items were identified. Effects of habitat structure on buzzard diet composition were investigated using correlation analysis. The most abundant group in buzzards’ diets were small rodents (49-80% of the biomass consumed, followed by other mammals and birds. Reptiles, anurans, fish and invertebrates constituted the rest. Proportions of all food items varied greatly between landscapes. The mean-weighted body mass of vertebrate prey hunted by common buzzards in different landscapes ranged from 107 to 244 g, constituting on average 180 g. Among small rodents, voles of the genus Microtus were hunted selectively. The food niche breadth was directly proportional to the amount of forest habitat. With increasing amount of forest habitat, the proportion of Microtus voles in buzzards’ diets decreased and the proportions of other food items grew. These findings confirm the majority of previous results indicating feeding opportunism of the common buzzard. Our investigation enables better understanding of predator-prey interactions and the prey choice of the common buzzard in Belarus.
Garcia-Montijano, Marino; Waxman, Samanta; Lucas, J Julio de; Luaces, Inés; Zalba, Javier; González, Fernando; Andrés, Manuel I San; Rodríguez, Casilda
2006-05-01
This study reports on the administration of a single dose of marbofloxacin (2 mg/kg) to five adult Eurasian buzzards (Buteo buteo) by the intraosseous (IO) route, which has been proposed as a rapid and efficient means for the parenteral delivery of antimicrobial drugs. The drug was rapidly absorbed. Peak marbofloxacin concentration (C(max)) in plasma and area under the concentration-time curve (AUC) of 1.92+/-0.78 microg/mL and 8.53+/-2.73 microg h/mL, respectively. The time marbofloxacin remained in the plasma after IO administration was relatively short (elimination half-life, t(1/2beta)=4.91+/-0.65 h; mean residence time (MRT)=5.38+/-0.57 h). Single dose marbofloxacin gave values for C(max)/minimum inhibitory concentration (MIC) of 19.2 and an AUC/MIC value of 85.3h after IO administration. The IO route appears to be practical and effective for the rapid delivery of marbofloxacin to buzzards.
Breeding biology and nest-site selection of red-tailed hawks in an altered desert grassland
Hobbs, R.J.; DeStefano, S.; Halvorson, W.L.
2006-01-01
Red-tailed Hawks (Buteo jamaicensis) have expanded their range as trees have invaded formerly-open grasslands. Desert grasslands of southern Arizona have been invaded by mesquite trees (Prosopis velutina) since Anglo-American settlement and now support a large population of Red-tailed Hawks. We studied a population of Red-tailed Hawks in an altered desert grassland in southern Arizona. Our objectives were to determine what environmental characteristics influence Red-tailed Hawk habitat selection in mesquite-invaded desert grasslands and to evaluate the habitat quality of these grasslands for Red-tailed Hawks based on nesting density, nest success, and productivity. Red-tailed Hawks had 86% (95% C.I. = 73-99) nest success and 1.82 young per breeding pair (95% C.I. = 1.41-2.23). Nesting density was 0.15 (95% CI = 0.08-0.21) breeding pairs/km2 and the mean nearest-neighbor distance was 1.95 km (95% C.I. = 1.74-2.16). Red-tailed Hawks selected nest-sites with taller nest-trees and greater tree height and cover than were available at random. Mesquite trees in desert grasslands provide abundant potential nesting structures for Red-tailed Hawks. ?? 2006 The Raptor Research Foundation, Inc.
Murdin, P.
2000-11-01
Cosmologist and theoretical astrophysicist, born in Oxford, England, where he studied physics at University College. Moved to Cambridge to take up research in general relativity and cosmology, became Lucasian professor (an appointment earlier held by ISAAC NEWTON, with whom Hawking has been compared). Hawking worked to develop a valid mathematical treatment of the `singularities' in the theor...
Hull, Joshua M; Hull, Angus C; Sacks, Benjamin N; Smith, Jeff P; Ernest, Holly B
2008-02-01
Landscape-scale population genetic structure in vagile vertebrates was commonly considered to be a contradiction in terms whereas recent studies have demonstrated behaviour and habitat associated structure in several such species. We investigate whether landscape features influence morphological and genetic differentiation in a widespread, mobile raptor. To accurately describe genetic differentiation associated with regional landscape factors, we first investigated subspecies relationships at a continental scale. We used 17 microsatellite loci and five morphological measurements to investigate differentiation between eastern and western subspecies of red-tailed hawks (Buteo jamaicensis) and to identify patterns between differentiation and habitat within western North America. Bayesian and frequency-based analyses of microsatellite data revealed clear distinctions between B. j. borealis (eastern) and B. j. calurus (western) samples. Furthermore, hawks sampled in Texas were stouter than those collected from the Rocky Mountains and farther west. Among western samples, birds from the Great Basin, Rocky Mountains, and Washington were significantly different in morphology than those from Oregon and California. We identified a pattern of isolation by distance among western breeding sites around the Sierra Nevada. Given the long-range dispersal capabilities of raptors, this pattern suggests that population-specific habitat preferences, corresponding with habitat breaks between eastern and western slopes of the Sierra Nevada, and/or regionally variable population densities limit migration between the Mediterranean habitat of central California and the xeric habitats of southern California and interior west. We suggest habitat preferences and regionally disparate population densities may play a role in shaping genetic structure in vagile avian taxa.
Gelli, D; Ferrari, V; Franceschini, F; Lai, O; Laricchiuta, P; Zanella, A; Bernardini, D; Romagnoli, S
2009-07-01
In avian medicine, hematologic and biochemical laboratory investigations are still in their infancy, because of the difficulty involved in collecting data. This has led to a lack of reference values and a nonstandardized approach to specimens obtained in critical conditions. The Eurasian Buzzard (Buteo buteo) is one of the most common raptors in Italy, yet little is known about the physiologic blood parameters of this species. Serum biochemistry and electrophoretic investigations were performed in 40 healthy Eurasian Buzzards in different Italian wildlife rescue centers waiting to be released after recovering from trauma injuries. Mean values for biochemistry parameters were pancreatic amylase 626.9 IU/l, uric acid 7.5 mg/dl, aspartate aminotransferase 330.9 IU/l, glucose 375.1 mg/dl, lipase 26.3 IU/ l, total protein 38.4 g/l, total bilirubin 0.04 mg/ dl, lactate dehydrogenase 2,008.4 IU/l, creatinine kinase 1,604.1 IU/l, alanine aminotransferase 40.4 IU/l, alkaline phosphatase 89.8 IU/l, magnesium 2.3 mg/dl, calcium 10.2 mg/dl, phosphorus 2.02 mg/dl, cholesterol 192.2 mg/ dl, triglyceride 116.4 mg/dl, albumin 14.5 g/l, creatinine 0.1 mg/dl. Mean electrophoretic values were prealbumin 1.4 g/l, albumin 14.2 g/l, alpha 1 globulin 5.9 g/l, alpha 2 globulin 4.7 g/l, beta globulin 7.5 g/l, gamma globulin 3.6 g/l, albumin/globulins ratio 0.8 g/l.
Productivity, mortality, and response to disturbance of nesting Swainson's hawks on the Hanford Site
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.
Nusbaum, Kenneth E; Wright, James C; Johnston, William B; Allison, Andrew B; Hilton, Clayton D; Staggs, Lydia A; Stallknecht, David E; Shelnutt, Joseph L
2003-01-01
Sixteen Chilean flamingos, Phoenicopterus chiles, and 10 red-tailed hawks, Buteo jamacensis, were vaccinated in the pectoral muscle with 0.2 ml of a commercially produced killed West Nile virus vaccine intended for use in horses. Half the birds of each species received a booster vaccination 3 weeks after the first injection. Three weeks after the booster vaccination, none of 13 birds surveyed had detectable antibody to West Nile virus.
Red-tailed Hawk movements and use of habitat in the Luquillo Mountains of Puerto Rico
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
Characterization of Sarcocystis from four species of hawks from Georgia, USA.
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.
A retrospective study of postmortem findings in red-tailed hawks
Franson, J.C.; Thomas, N.J.; Smith, M.R.; Robbins, A.H.; Newman, S.; McCartin, P.C.
1996-01-01
We studied necropsy results from carcasses of 163 red-tailed hawks (Buteo jamaicensis) submitted to the National Wildlife Health Center from 1975 through 1992. The most frequent postmortem finding was emaciation of unknown etiology, diagnosed in 33 (20%) carcasses. Proportionally more juveniles than adults were emaciated. Evidence of non-gunshot trauma, often suggestive of collision with vehicles or structures near roadways, was found in 29 (18%) birds. Of 25 (15%) toxicoses, 20 were attributed to agricultural pesticides, including famphur (4), fenthion (3), carbofuran (2), phosphamidon (2), endrin (1), and unidentified organophosphorus compounds (8). Lead and strychnine poisoning were diagnosed in two birds each, and selenium poisoning in one. Diseases, including aspergillosis, tuberculosis, pasteurellosis, and pox, were found in 21 (13%) hawks. Gunshot and electrocution were each diagnosed in six (4%) birds, one (0.6%) was trapped, miscellaneous conditions were found in 10 (6%), and no diagnosis could be determined for 32 (19%) of the carcasses.
A retrospective study of postmortem findings in red-tailed hawks
Franson, J.C.; Thomas, N.J.; Smith, M.R.; Robbins, A.H.; Newman, S.; McCartin, P.C.
1996-01-01
We studied necropsy results from carcasses of 163 red-tailed hawks (Buteo jamaicensis) submitted to the National Wildlife Health Center from 1975 through 1992. The most frequent postmortem finding was emaciation of unknown etiology, diagnosed in 33 (20%) carcasses. Proportionally more juveniles than adults were emaciated. Evidence of non-gunshot trauma, often suggestive of collision with vehicles or structures near roadways, was found in 29 (18%) birds. Of 25 (15%) toxicoses, 20 were attributed to agricultural pesticides, including famphur (4), fenthion (3), carbofuran (2), phosphamidon (2), endrin (1), and unidentified organophosphorus compounds (8). Lead and strychnine poisoning were diagnosed in two birds each, and selenium poisoning in one. Diseases, including aspergillosis, tuberculosis, pasteurellosis, and pox, were found in 21 (13%) hawks. Gunshot and electrocution were each diagnosed in six (4%) birds, one (0.6%) was trapped, miscellaneous conditions were found in 10 (6%), and no diagnosis could be determined for 32 (19%) of the carcasses.
Perfect simulation of Hawkes processes
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...
Steven Hawking with Robert Aymar
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.
Habitat Effects on the Breeding Performance of Three Forest-Dwelling Hawks.
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.
Hawking radiation is corpuscular
Mück, Wolfgang
2016-01-01
The total number of Hawking quanta emitted during the evaporation of a Schwarzschild black hole is proportional to the square of the initial mass and proportional to the Bekenstein entropy. This simple, but seemingly unnoticed, fact is interpreted in terms of the recent discovery of black hole soft hair.
Are red-tailed hawks and great horned owls diurnal-nocturnal dietary counterparts?
Marti, C.D.; Kochert, Michael N.
1995-01-01
Red-tailed Hawks (Buteo jamaicensis) and Great Homed Owls (Bubo virginianus)are common in North America where they occupy a wide range of habitats, often sympatrically. The two species are similar in size and have been portrayed as ecological counterparts, eating the same prey by day and night. We tested the trophic similarity of the two species by comparing published dietary data from across the United States. Both species ate primarily mammals and birds, and mean proportions of those two prey types did not differ significantly between diets of the two raptors. Red-tailed Hawks ate significantly more reptiles, and Great Homed Owls significantly more invertebrates. Dietary diversity was not significantly different at the level of prey taxonomic class, and diet overlap between the two species averaged 91%. At the prey species level, dietary overlap averaged only 50%, and at that level Red-tailed Hawk dietary diversity was significantly greater than that of Great Horned Owls. Mean prey mass of Red-tailed Hawks was significantly greater than that of Great Homed Owls. Populations of the two species in the western United States differed trophically more than did eastern populations. We conclude that, although the two species are generalist predators, they take largely different prey species in the same localities resulting in distinctive trophic characteristics.
Sakalli, I; Pasaoglu, H
2012-01-01
In this study, we explore a particular type Hawking radiation which ends with zero temperature and entropy. The appropriate black holes for this purpose are the linear dilaton black holes. In addition to the black hole choice, a recent formalism in which the Parikh-Wilczek's tunneling formalism amalgamated with quantum corrections to all orders in \\hbar is considered. The adjustment of the coefficients of the quantum corrections plays a crucial role on this particular Hawking radiation. The obtained tunneling rate indicates that the radiation is not pure thermal anymore, and hence correlations of outgoing quanta are capable of carrying away information encoded within them. Finally, we show in detail that when the linear dilaton black hole completely evaporates through such a particular radiation, entropy of the radiation becomes identical with the entropy of the black hole, which corresponds to "no information loss".
Canadian institute honours Hawking
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.
Boal, C.W.; Snyder, H.A.; Bibles, B.D.; Estabrook, T.S.
2003-01-01
We mapped Red-tailed Hawk (Buteo jamaicensis) territories in the Luquillo Experimental Forest (LEF) of Puerto Rico in 1998. We combined our 1998 data with that collected during previous studies of Red-tailed Hawks in the LEF to examine population numbers and spatial stability of territorial boundaries over a 26-yr period. We also investigated potential relationships between Red-tailed Hawk territory sizes and topographic and climatic factors. Mean size of 16 defended territories during 1998 was 124.3 ?? 12.0 ha, which was not significantly different from our calculations of mean territory sizes derived from data collected in 1974 and 1984. Aspect and slope influenced territory size with the smallest territories having high slope and easterly aspects. Territory size was small compared to that reported for other parts of the species' range. In addition, there was remarkably little temporal change in the spatial distribution, area, and boundaries of Red-tailed Hawk territories among the study periods. Further, there was substantial boundary overlap (21-27%) between defended territories among the different study periods. The temporal stability of the spatial distribution of Red-tailed Hawk territories in the study area leads us to believe the area might be at or near saturation.
Hawking Radiation in Dispersive Media
Robertson, Scott James
2011-01-01
Hawking radiation, despite its presence in theoretical physics for over thirty years, remains elusive and undetected. It also suffers, in its original context of gravitational black holes, from conceptual difficulties. Of particular note is the trans-Planckian problem, which is concerned with the apparent origin of the radiation in absurdly high frequencies. In order to gain better theoretical understanding and, it is hoped, experimental verification of Hawking radiation, much study is being devoted to systems which model the spacetime geometry of black holes, and which, by analogy, are also thought to emit Hawking radiation. These analogue systems typically exhibit dispersion, which regularizes the wave behaviour at the horizon but does not lend itself well to analytic treatment, thus rendering Hawking's prediction less secure. A general analytic method for dealing with Hawking radiation in dispersive systems has proved difficult to find. This thesis presents new numerical and analytic results for Hawking em...
Serological and parasitological prevalence of Toxoplasma gondii in wild birds from Colorado.
Dubey, J P; Felix, T A; Kwok, O C H
2010-10-01
Ground-feeding birds are considered important in the epidemiology of Toxoplasma gondii because they serve as indicators of soil contamination by oocysts, and birds of prey are indicators of T. gondii prevalence in rodents and other small mammals. Cats excrete environmentally resistant oocysts after consuming tissues of T. gondii -infected birds. In the present study, sera and tissues from 382 wild birds from Colorado were tested for T. gondii infection. Antibodies to T. gondii were found in 38 birds with the use of the modified agglutination test (MAT, 1∶25 titer). Tissues (brains, hearts) of 84 birds were bioassayed in mice. Viable T. gondii was isolated from 1 of 1 barn owl (Tyto alba), 1 of 5 American kestrels (Falco sparverius), 1 of 7 ferruginous hawks (Buteo regalis), 1 of 4 rough-legged hawks (Buteo lagopus), 2 of 13 Swainson's hawks (Buteo swainsoni), and 1 of 25 red-tailed hawks (Buteo jamaicensis). This is the first time T. gondii has been isolated from the barn owl, ferruginous hawk, rough-legged hawk, and Swainson's hawk.
Approximate simulation of Hawkes processes
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...
Perfect simulation of Hawkes processes
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...
Chinese President Meets Stephen Hawking
Fu Shuqin
2002-01-01
@@ Chinese President Jiang Zemin met on August 19 with Stephen Hawking and other world-renown scientists, including Shing-tung Yau, Edward Witten, D.Gross, A. Strominger, et al., who were attending an international conference on string theory and Prof.Hawking had just given a public speech titled "Brane New World" in Beijing.
Searcy, Yvonne M; Caine, Nancy G
2003-01-01
Most descriptions of callitrichid antipredator behavior have come from observations of visual encounters with predators, but there is also anecdotal evidence suggesting that callitrichids may use auditory cues associated with raptors for the early detection of potential danger. In the present study, Geoffroy's marmosets consistently reacted to the tape-recorded calls of a red-tailed hawk (Buteo jamaicensis) with high-intensity antipredator behaviors. Compared to the taped calls of a raven (Corvus corax) and the taped sound of a power drill, the hawk calls elicited more startle reactions, more alarm calls, longer freeze times, increased use of safe areas of their enclosure and greater disruption in ongoing behavior. Once in a relatively safe location in the enclosure, the marmosets visually monitored the site of origin of the calls for 10 min and minimized locomotion for 30 min, but resumed baseline levels of other activities that had been disrupted by the hawk calls. Marmosets may use the auditory cues associated with predators for early detection, and subsequent avoidance, of a potential predator in the vicinity.
What is your diagnosis? Blood smear from an injured red-tailed hawk.
Johns, Jennifer L; Luff, Jennifer A; Shooshtari, Mahrokh P; Zehnder, Ashley M; Borjesson, Dori L
2009-06-01
An injured juvenile red-tailed hawk (Buteo jamaicensis) was evaluated at the Veterinary Medical Teaching Hospital at the University of California, Davis. The hawk was quiet, alert, and emaciated, and had a closed comminuted, mid-diaphyseal ulnar fracture. CBC results included heterophilia with a left shift, monocytosis, and increased plasma fibrinogen concentration. The blood smear included rare heterophils containing small, dark blue inclusions approximately 1-2 mum in diameter that ranged from round to coccobacillary in shape and formed variably shaped aggregates; the morphology of the inclusions was suspicious for Chlamydophila or Ehrlichia spp. pathogens. The hawk died, and histopathologic examination of tissues obtained at necropsy found severe multifocal histiocytic and heterophilic splenitis in addition to chronic hepatitis, myocarditis and epicarditis, meningoencephalitis, and airsacculitis. Using immunohistochemistry the presence of Chlamydia/Chlamydophila spp. antigen within multiple tissues was confirmed. Chlamydophila psittaci DNA was demonstrated in whole blood and fresh splenic tissue via real-time PCR. Direct fluorescent antibody staining of air-dried blood smears was positive in rare leukocytes for Chlamydia/Chlamydophila spp. antigen, and immunocytochemical staining of blood smears for Chlamydia/Chlamydophila spp. antigen was focally positive in rare heterophils. These findings may represent the first reported diagnosis of natural avian C. psittaci infection by visualization of organisms in peripheral blood heterophils. Immunocytochemical evaluation of blood smears was valuable in confirming the diagnosis and may be a useful antemortem test to discriminate between bacteria and other inclusions within heterophils.
Barsotti, Giovanni; Briganti, Angela; Spratte, Johanna Roselinde; Ceccherelli, Renato; Breghi, Gloria
2010-09-01
To evaluate the achievement of a bilateral mydriasis in raptors induced by a concurrent topical application of rocuronium bromide and to assess any side effects that might result from its use. Animals studied Ten healthy adult common buzzards (Buteo buteo) and 10 healthy adult little owls (Athene noctua). Common buzzards (Group 1) received a single dose of 0.40 mg of rocuronium bromide in each eye (total dose 0.80 mg/bird), whereas the little owls (Group 2) received a single dose of 0.20 mg in each eye (total dose 0.40 mg/bird). The drug was topically instilled in all the birds of both groups. The pupil diameter was measured with a pupillary gauge and the assessment of the pupillary light reflexes was performed using a standard light source. Maximal pupillary diameter was 8.10 ± 0.56 mm in the right eye and 8.05 ± 0.59 mm in the left eye for Group 1 and 10.0 ± 0.75 mm in both eyes for Group 2. No statistical differences were evidenced between the achieved pupillary diameters of both eyes in each group. The maximal pupillary diameter was achieved at T110 min and T40 min for Groups 1 and 2, respectively. The drug did not cause noticeable adverse effects in the examined birds. A single concurrent topical administration of rocuronium bromide to the eyes of the examined birds induced a complete bilateral mydriasis in both eyes without causing any adverse effect.
Svobodová, Milena; Weidinger, Karel; Peške, Lubomír; Volf, Petr; Votýpka, Jan; Voříšek, Petr
2015-02-01
The prevalences of heteroxenous parasites are influenced by the interplay of three main actors: hosts, vectors, and the parasites themselves. We studied blood protists in the nesting populations of raptors in two different areas of the Czech Republic. Altogether, 788 nestlings and 258 adult Eurasian sparrowhawks (Accipiter nisus) and 321 nestlings and 86 adult common buzzards (Buteo buteo) were screened for parasites by the microscopic examination of blood smears and by cultivation. We examined the role of shared vectors and parasite phylogenetic relationships on the occurrence of parasites. In different years and hosts, trypanosome prevalence ranged between 1.9 and 87.2 %, that of Leucocytozoon between 1.9 and 100 %, and Haemoproteus between 0 and 72.7 %. Coinfections with Leucocytozoon and Trypanosoma, phylogenetically distant parasites but both transmitted by blackflies (Simuliidae), were more frequent than coinfections with Leucocytozoon and Haemoproteus, phylogenetically closely related parasites transmitted by different vectors (blackflies and biting midges (Ceratopogonidae), respectively). For example, 16.6 % buzzard nestlings were coinfected with Trypanosoma and Leucocytozoon, while only 4.8 % with Leucocytozoon and Haemoproteus and 0.3 % with Trypanosoma and Haemoproteus. Nestlings in the same nest tended to have the same infection status. Furthermore, prevalence increased with the age of nestlings and with Julian date, while brood size had only a weak negative/positive effect on prevalence at the individual/brood level. Prevalences in a particular avian host species also varied between study sites and years. All these factors should thus be considered while comparing prevalences from different studies, the impact of vectors being the most important. We conclude that phylogenetically unrelated parasites that share the same vectors tend to have similar distributions within the host populations of two different raptor species.
Fitzpatrick, A Liam; Walters, Matthew T; Wang, Junpu
2015-01-01
The Virasoro algebra determines all `graviton' matrix elements in AdS$_3$/CFT$_2$. We study the explicit exchange of any number of Virasoro gravitons between heavy and light CFT$_2$ 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 AdS$_3$ theories.
Variation in selected hematological parameters of captive red-tailed hawks.
Rehder, N B; Bird, D M; Laguë, P C; Mackay, C
1982-01-01
Diurnal and winter variations of four hematological parameters were examined in 10 red-tailed hawks (Buteo jamaicensis). The mean values obtained were: 39.4% packed cell volume (PCV); 2.45 X 10(6) erythrocytes (RBC) per mm3 of blood; 5.73 mg of calcium and 1.44 mg of magnesium per 100 ml of plasma. Only the PCV and RBC count showed significant diurnal variation. When the birds were sampled at a set time of day, from November through to February, no significant changes were detected in any of the four parameters. Variation among the birds in RBC count, PCV and calcium concentration was significant on a diurnal basis but over the four month period only the PCV varied significantly.
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.
Development of the Hawk/Nike Hawk sounding rocket vehicles
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.
Development of the Hawk/Nike Hawk sounding rocket vehicles
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.
Swainson's Hawk - Monitoring [ds5
California Department of Resources — These data do not represent a complete census of Swainson's hawks in the Department of Fish and Game's Central Valley Central Sierra Region. Different sample blocks...
UAVSAR Global Hawk POLSAR Project
National Aeronautics and Space Administration — Integrate the UAVSAR L-band radar to the Global Hawk UAV Bay 25 Provide long range (~ 9000 nmi) to enable data collection of distant areas of interest without...
Bermingham Eldredge
2006-02-01
Full Text Available Abstract Background The family Accipitridae (hawks, eagles and Old World vultures represents a large radiation of predatory birds with an almost global distribution, although most species of this family occur in the Neotropics. Despite great morphological and ecological diversity, the evolutionary relationships in the family have been poorly explored at all taxonomic levels. Using sequences from four mitochondrial genes (12S, ATP8, ATP6, and ND6, we reconstructed the phylogeny of the Neotropical forest hawk genus Leucopternis and most of the allied genera of Neotropical buteonines. Our goals were to infer the evolutionary relationships among species of Leucopternis, estimate their relationships to other buteonine genera, evaluate the phylogenetic significance of the white and black plumage patterns common to most Leucopternis species, and assess general patterns of diversification of the group with respect to species' affiliations with Neotropical regions and habitats. Results Our molecular phylogeny for the genus Leucopternis and its allies disagrees sharply with traditional taxonomic arrangements for the group, and we present new hypotheses of relationships for a number of species. The mtDNA phylogenetic trees derived from analysis of the combined data posit a polyphyletic relationship among species of Leucopternis, Buteogallus and Buteo. Three highly supported clades containing Leucopternis species were recovered in our phylogenetic reconstructions. The first clade consisted of the sister pairs L. lacernulatus and Buteogallus meridionalis, and Buteogallus urubitinga and Harpyhaliaetus coronatus, in addition to L. schistaceus and L. plumbeus. The second clade included the sister pair Leucopternis albicollis and L. occidentalis as well as L. polionotus. The third lineage comprised the sister pair L. melanops and L. kuhli, in addition to L. semiplumbeus and Buteo buteo. According to our results, the white and black plumage patterns have evolved
Whiteman, N.K.; Matson, K.D.; Bollmer, J.L.; Parker, P.G.
2006-01-01
An increased susceptibility to disease is one hypothesis explaining how inbreeding hastens extinction in island endemics and threatened species. Experimental studies show that disease resistance declines as inbreeding increases, but data from in situ wildlife systems are scarce. Genetic diversity
Sakalli, I
2014-01-01
We show in detail that the Parikh-Wilczek tunneling method (PWTM), which was designed for resolving the information loss problem in Hawking radiation (HR)fails whenever the radiation occurs from an isothermal process. The PWTM aims to produce a non-thermal HR which adumbrates the resolution of the problem of unitarity in quantum mechanics (QM), and consequently the entropy (or information) conservation problem. The effectiveness of the method has been satisfactorily tested on numerous black holes (BHs). However, it has been shown that the isothermal HR, which results from the emission of the uncharged particles of the linear dilaton BH (LDBH) described in the Einstein-Maxwell-Dilaton (EMD) theory, the PWTM has vulnerability in having non-thermal radiation. In particular, we consider Painlev\\'{e}-Gullstrand coordinates (PGCs) and isotropic coordinates (ICs) in order to prove the aformentioned failure in the PWTM. While carrying out calculations in the ICs, we also highlight the effect of the refractive index o...
Sakalli, I.; Ovgun, A.
2015-04-01
We show in detail that the Parikh-Wilczek tunneling method (PWTM), which was designed for resolving the information loss problem in Hawking radiation (HR) fails whenever the radiation occurs from an isothermal process. The PWTM aims to produce a non-thermal HR which adumbrates the resolution of the problem of unitarity in quantum mechanics (QM), and consequently the entropy (or information) conservation problem. The effectiveness of the method has been satisfactorily tested on numerous black holes (BHs). However, it has been shown that the isothermal HR, which results from the emission of the uncharged particles of the linear dilaton BH (LDBH) described in the Einstein-Maxwell-Dilaton (EMD) theory, the PWTM has vulnerability in having non-thermal radiation. In particular, we consider Painlevé-Gullstrand coordinates (PGCs) and isotropic coordinates (ICs) in order to prove the aforementioned failure in the PWTM. While carrying out calculations in the ICs, we also highlight the effect of the refractive index on the null geodesics.
Vacuum polarization and Hawking radiation
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.
Elliott, J E; Langelier, K M; Mineau, P; Wilson, L K
1996-07-01
During the winter of 1990 in the Fraser Delta of British Columbia, Canada, nine birds of prey were found with symptoms of anticholinesterase poisoning. Immediate surgical removal of crop contents of three birds decreased mortality and recovery time. Chemical analysis was conducted on crop contents, which contained mainly duck parts. A bald eagle (Haliaeetus leucocephalus) contained 200 micrograms/g and a red-tailed hawk (Buteo jamaicensis) 2.2 micrograms/g carbofuran, while the crop of another red-tailed hawk contained 30 micrograms/g fensulfothion. There was evidence that granular carbofuran and fensulfothion persisted long enough in the wet, low pH conditions of the Fraser Delta to kill waterfowl and cause secondary poisoning of raptors several months after application of the pesticides.
Hawk migration over White Marsh, Maryland
Hackman, C.D.; Henny, C.J.
1971-01-01
The average number of hawks observed per hour in autumn migration between 1951-1954 and 1958-1961 at White Marsh, Maryland, was compared. The counts indicated that the status of the ten species observed may be divided into three categories: (1) relatively stable species (red-tailed hawk), (2) declining species (sparrow hawk, red-shouldered hawk, osprey, marsh hawk, and broad-winged hawk), and (3) rapidly declining species (peregrine falcon, Cooper?s hawk, bald eagle, and sharp-shinned hawk). The findings from this study are in agreement with the available literature and the status of the populations appears to be related to the food habits of the species.
Stephen Hawking: An Unfettered Mind
Ferguson, Kitty
2012-02-23
Kitty Ferguson, biographer of physicist Stephen Hawking, will give an informal, nontechnical talk about the experience of writing her two books about the celebrated cosmologist and also of helping Hawking edit his own “The Universe in a Nutshell”. Hawking thinks and works somewhat differently from others because he must work almost entirely in his head, and he has a practice of pulling the rug out from under his own discoveries and assertions. As he has approached his recent 70th birthday, he has devoted an increasing amount of his time in efforts to share his science and particularly the adventure of it with people without a science background and young people who may be scientists of the future. Ferguson will discuss Hawking’s place in the science community (he is not and has never claimed to be on par with Einstein), the unique contributions he is able to make, and what his legacy might be.
Hawking radiation without transplanckian frequencies
Brout, R; Parentani, R; Spindel, P
1995-01-01
In a recent work, Unruh showed that Hawking radiation is unaffected by a truncation of free field theory at the Planck scale. His analysis was performed numerically and based on a hydrodynamical model. In this work, by analytical methods, the mathematical and physical origin of Unruh's result is revealed. An alternative truncation scheme which may be more appropriate for black hole physics is proposed and analyzed. In both schemes the thermal Hawking radiation remains unaffected even though transplanckian energies no longer appear. The universality of this result is explained by working in momentum space. In that representation, in the presence of a horizon, the d'Alembertian equation becomes a singular first order equation. In addition, the boundary conditions corresponding to vacuum before the black hole formed are that the in--modes contain positive momenta only. Both properties remain valid when the spectrum is truncated and they suffice to obtain Hawking radiation.
Second order analysis for spatial Hawkes processes
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....
Peters, Susan E; Dobbins, Charles S
2012-03-01
A comparison of the isometric forces and levers of the pectoralis muscle in red-tailed hawks (Buteo jamaicensis) and barred owls (Strix varia) was done to identify differences that may correlate with their different flight styles. The pectoralis consists of two heads, the anterior m. sternobrachialis (SB) and the posterior m. thoracobrachialis (TB). These are joined at an intramuscular tendon and are supplied by separate primary nerve branches. As in other birds, the two heads have distinct fiber orientations in red-tailed hawks and barred owls. SB's fiber orientation (posterolateral and mediolateral from origin to insertion) provides pronation and protraction of the humerus during adduction. Electromyographic studies in pigeons show that it is active in early downstroke and during level flight. TB is more active during take-off and landing in pigeons. The anterolateral orientation (from origin to insertion) of its fibers provides a retractive component to humeral adduction used to control the wing during landing. In our study, the maximum isometric force produced by the combined pectoralis heads did not differ significantly between the hawk and owl, however, the forces were distributed differently between the two muscle heads. In the owl, SB and TB were capable of producing equal amounts of force, but in the hawk, SB produced significantly less force than did TB. This may reflect the need for a large TB to control landing in both birds during prey-strike, with the owl maintaining both protractive (using SB) and retractive (using TB) abilities. Pronation and protraction may be less important in the flight behavior of the hawk, but its prey-strike behavior may require the maintenance of a substantial TB for braking and controlled stalling, as it initiates strike behavior.
Ketamine-xylazine anesthesia in red-tailed hawks with antagonism by yohimbine.
Degernes, L A; Kreeger, T J; Mandsager, R; Redig, P T
1988-04-01
Five red-tailed hawks (Buteo jamaicensis) were anesthetized at weekly intervals with intravenous ketamine hydrochloride (KET, 4.4 mg/kg) and xylazine hydrochloride (XYL, 2.2 mg/kg). Twenty min after anesthesia, yohimbine hydrochloride (YOH, 0.05, 0.10, 0.20 and 0.40 mg/kg) or a control was administered. All doses of YOH significantly reduced the head-up times (F = 20.84, df = 1,24, P less than 0.0001) and the standing times (F = 12.30, df = 1,24, P less than 0.0001), compared to the control group. The heart and respiratory rates following YOH (all doses) were significantly greater (P less than 0.01) than the anesthetized rates, but were comparable to the rates observed in restrained, unanesthetized hawks. Yohimbine did not appear to have any significant effect on body temperature. Based upon administration of 4.4 mg/kg KET and 2.2 mg/kg XYL, a dose of 0.10 mg/kg YOH was recommended to achieve antagonism without causing profound cardiovascular or respiratory changes.
2007-08-01
New Wide Field Near-Infrared Imager for ESO's Very Large Telescope Europe's flagship ground-based astronomical facility, the ESO VLT, has been equipped with a new 'eye' to study the Universe. Working in the near-infrared, the new instrument - dubbed HAWK-I - covers about 1/10th the area of the Full Moon in a single exposure. It is uniquely suited to the discovery and study of faint objects, such as distant galaxies or small stars and planets. ESO PR Photo 36a/07 ESO PR Photo 36a/07 HAWK-I on the VLT After three years of hard work, HAWK-I (High Acuity, Wide field K-band Imaging) saw First Light on Yepun, Unit Telescope number 4 of ESO's VLT, on the night of 31 July to 1 August 2007. The first images obtained impressively demonstrate its potential. "HAWK-I is a credit to the instrument team at ESO who designed, built and commissioned it," said Catherine Cesarsky, ESO's Director General. "No doubt, HAWK-I will allow rapid progress in very diverse areas of modern astronomy by filling a niche of wide-field, well-sampled near-infrared imagers on 8-m class telescopes." "It's wonderful; the instrument's performance has been terrific," declared Jeff Pirard, the HAWK-I Project Manager. "We could not have hoped for a better start, and look forward to scientifically exciting and beautiful images in the years to come." During this first commissioning period all instrument functions were checked, confirming that the instrument performance is at the level expected. Different astronomical objects were observed to test different characteristics of the instrument. For example, during one period of good atmospheric stability, images were taken towards the central bulge of our Galaxy. Many thousands of stars were visible over the field and allowed the astronomers to obtain stellar images only 3.4 pixels (0.34 arcsecond) wide, uniformly over the whole field of view, confirming the excellent optical quality of HAWK-I. ESO PR Photo 36b/07 ESO PR Photo 36c/07 Nebula in Serpens (HAWK
Bayesian inference for Hawkes processes
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...
Bayesian inference for Hawkes processes
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...
Bayesian inference for Hawkes processes
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...
Stephen Hawking's Universe. Teacher's Guide.
Thompson, Malcolm H.; Rameau, Jonathan D.
This program guide is meant to help teachers assist their students in viewing the six-part public television series, "Stephen Hawking's Universe." The guide features program summaries that give background information and brief synopses of the programs; previewing activities that familiarize students with the subject; vocabulary that…
Approximate simulation of Hawkes processes
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...
Hawking Colloquium Packed CERN Auditoriums
2006-01-01
Stephen Hawking's week long visit to CERN included an 'exceptional CERN colloquium' which filled six auditoriums. Stephen Hawking during his visit to the ATLAS experiment. Stephen Hawking, Lucasian Professor of Cambridge University, visited the Theory Unit of the Physics Department from 24 September to 1 October 2006. As part of his visit, he gave two lectures in the main auditorium - a theoretical seminar on 'The Semi-Classical Birth of The Universe', attended by about 120 specialists; and a colloquium titled 'The Origin of The Universe'. As a key public figure in theoretical physics, his presence was eagerly awaited on both occasions. Those who wanted to attend the colloquium had to arrive early and be equipped with plenty of patience. An hour before it was due to begin, the 400 capacity of the main auditorium was already full. The lecture, simultaneously broadcast to five other fully packed CERN auditoriums, was attended by an estimated total of 850. Stephen Hawking attracted a large CERN crowd, filling ...
Red-shouldered hawk occupancy surveys in central Minnesota, USA
Henneman, C.; McLeod, M.A.; Andersen, D.E.
2007-01-01
Forest-dwelling raptors are often difficult to detect because many species occur at low density or are secretive. Broadcasting conspecific vocalizations can increase the probability of detecting forest-dwelling raptors and has been shown to be an effective method for locating raptors and assessing their relative abundance. Recent advances in statistical techniques based on presence-absence data use probabilistic arguments to derive probability of detection when it is <1 and to provide a model and likelihood-based method for estimating proportion of sites occupied. We used these maximum-likelihood models with data from red-shouldered hawk (Buteo lineatus) call-broadcast surveys conducted in central Minnesota, USA, in 1994-1995 and 2004-2005. Our objectives were to obtain estimates of occupancy and detection probability 1) over multiple sampling seasons (yr), 2) incorporating within-season time-specific detection probabilities, 3) with call type and breeding stage included as covariates in models of probability of detection, and 4) with different sampling strategies. We visited individual survey locations 2-9 times per year, and estimates of both probability of detection (range = 0.28-0.54) and site occupancy (range = 0.81-0.97) varied among years. Detection probability was affected by inclusion of a within-season time-specific covariate, call type, and breeding stage. In 2004 and 2005 we used survey results to assess the effect that number of sample locations, double sampling, and discontinued sampling had on parameter estimates. We found that estimates of probability of detection and proportion of sites occupied were similar across different sampling strategies, and we suggest ways to reduce sampling effort in a monitoring program.
Cuckoo-hawk mimicry? An experimental test.
Davies, N B; Welbergen, J A
2008-08-07
The similarity between many Old World parasitic cuckoos (Cuculinae) and Accipiter hawks, in size, shape and plumage, has been noted since ancient times. In particular, hawk-like underpart barring is more prevalent in parasitic than in non-parasitic cuckoos. Cuckoo-hawk resemblance may reflect convergent evolution of cryptic plumage that reduces detection by hosts and prey, or evolved mimicry of hawks by parasitic cuckoos, either for protection against hawk attacks or to facilitate brood parasitism by influencing host behaviour. Here, we provide the first evidence that some small birds respond to common cuckoos Cuculus canorus as if they were sparrowhawks Accipiter nisus. Great tits and blue tits were equally alarmed and reduced attendance at feeders during and after the presentation of mounted specimens of common cuckoos and sparrowhawks, but not in response to control presentations of collared doves or teal. Plumage manipulations revealed that the strong alarm response to cuckoos depended on their resemblance to hawks; cuckoos with barred underparts were treated like hawks, while those with unbarred underparts were treated like doves. However, barring was not the only feature inducing alarm because tits showed similarly strong alarm to barred and unbarred hawks, and little alarm to barred doves. These responses of tits, unsuitable as hosts and hence with no history of cuckoo parasitism, suggest that naive small birds can mistake cuckoos for hawks. Thus, any cuckoo-hawk discrimination by host species is likely to be an evolved response to brood parasitism.
Hawking Radiation and Classical Tunneling
Tracy, Eugene R
2015-01-01
Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by Unruh and others as a conceptual model for `Hawking radiation.' Here we use variational methods, originally introduced by Brizard for the study of linearized MHD, and ray phase space methods, to analyze linearized acoustics in the presence of background flows. The variational formulation endows the evolution equations with natural Hermitian and symplectic structures that prove useful for later analysis. We derive a $2\\times 2$ normal form governing the wave evolution in the vicinity of the `event horizon.' This shows that the acoustic model can be reduced locally (in ray phase space) to a standard (scalar) tunneling process weakly coupled to a unidirectional non-dispersive wave (the `incoming wave'). Given the normal form, the Hawking `thermal spectrum' can be derived by invok...
Stephen Hawking returns to CERN
2009-01-01
Stephen Hawking visiting the CERN Control Centre.If you happened to pass through Building 4 during the first weeks of September, you might have noticed the name of Stephen Hawking on one of the doors on the second floor, which hosts most of CERN theorists’ offices. Three years after his last visit to CERN, Stephen Hawking gladly accepted the invitation from the University of Geneva to hold a public lecture on the occasion of its 450th anniversary and requested an office at CERN for the length of his stay. The "master of the Universe", as the Geneva University journal dubbed him, attracted over 4000 people to his lecture on "The Creation of the Universe" held on 15 September in the Main Auditorium of Uni Dufour. His more technical colloquium on the same subject at CERN a week earlier, was no less popular and quite "provocative" according to some of the physicists in the audience. With his repeated reference to the "non-need" for a "creating agent" for the Universe, mo...
Central Limit Theorem for Nonlinear Hawkes Processes
Zhu, Lingjiong
2012-01-01
Hawkes process is a self-exciting point process with clustering effect whose jump rate depends on its entire past history. It has wide applications in neuroscience, finance and many other fields. Linear Hawkes process has an immigration-birth representation and can be computed more or less explicitly. It has been extensively studied in the past and the limit theorems are well understood. On the contrary, nonlinear Hawkes process lacks the immigration-birth representation and is much harder to analyze. In this paper, we obtain a functional central limit theorem for nonlinear Hawkes process.
Hawking Temperature of Acoustic Black Hole
Zhi Kun Xie
2014-09-01
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.
Introducing Stephen Hawking a graphic guide
McEvoy, JP
2014-01-01
Stephen Hawking is the world-famous physicist. To the public he is a tragic figure - a brilliant scientist and author of the 9 million-copy-selling ""A Brief History of Time"", and yet confined to a wheelchair and almost completely paralysed. This guide explores Hawking's life, and the evolution of his work from his days as a student.
Lautenschlager, Stephan; Bright, Jen A; Rayfield, Emily J
2014-04-01
Gross dissection has a long history as a tool for the study of human or animal soft- and hard-tissue anatomy. However, apart from being a time-consuming and invasive method, dissection is often unsuitable for very small specimens and often cannot capture spatial relationships of the individual soft-tissue structures. The handful of comprehensive studies on avian anatomy using traditional dissection techniques focus nearly exclusively on domestic birds, whereas raptorial birds, and in particular their cranial soft tissues, are essentially absent from the literature. Here, we digitally dissect, identify, and document the soft-tissue anatomy of the Common Buzzard (Buteo buteo) in detail, using the new approach of contrast-enhanced computed tomography using Lugol's iodine. The architecture of different muscle systems (adductor, depressor, ocular, hyoid, neck musculature), neurovascular, and other soft-tissue structures is three-dimensionally visualised and described in unprecedented detail. The three-dimensional model is further presented as an interactive PDF to facilitate the dissemination and accessibility of anatomical data. Due to the digital nature of the data derived from the computed tomography scanning and segmentation processes, these methods hold the potential for further computational analyses beyond descriptive and illustrative proposes.
P. Licata
2010-01-01
Full Text Available The purpose of this study was to determine the concentrations of heavy metals (Cd, Pb, Cu, Mn, and Zn in different organs (liver, kidney, muscle, lung, skin, and feathers of buzzards (Buteo buteo, utilized as a “biological indicator” for environmental contamination, from different areas of Sicily and to investigate the relationships between birds sex, age, and weight and metal levels in these samples. All samples of common buzzards were collected at the “Recovery Center of Wild Fauna” of Palermo, through the Zooprophilactic Institute. Potentiometric stripping analysis (PSA was used to determine the content of Cd(II, Cu(II, Mn(II, Pb(II, and Zn(II in bird tissues. For toxic metals, the highest levels of Pb were in liver and those of Cd in lung; Zn levels were higher than Cu and Mn in all tissues analyzed. The concentrations in liver, lung, kidney, and muscle could be considered as an indicative of chronic exposure to metals while the presence of metals in skin could be consequential to storing and elimination processes. The found concentrations of metals in the studied matrices required a highly sensitive method for their determination and a simple sample preparation procedure, and the proposed method was well suited for this purpose.
Redig, P T; Dunnette, J L; Sivanandan, V
1984-11-01
Mitogen-induced whole blood lymphocyte stimulation tests for immunocompetency studies in bald eagles (Haliaeetus leucocephalus), red-tailed hawks (Buteo jamaicensis), and great horned owls (Bubo virginianus) were developed. Combinations of incubation times, blood dilutions, concentrations of [3H]thymidine and [125I]2-deoxyuridine, antibiotics, phytohemagglutinin-P, and concanavalin A were tested for their effects on the stimulation index (SI). An antibiotic combination of gentamicin plus amphotericin B yielded low SI with lymphocytes from bald eagles, but not with lymphocytes from great horned owls or red-tailed hawks. Penicillin plus streptomycin caused no such depression of SI. Lymphocytes from all 3 species yielded maximum responses with a 48-hour prelabel and 12- to- 16 hour postlabel incubation period at 41 C and 1:20 blood dilution. Optimal mitogen concentrations for lymphocytes from bald eagles, red-tailed hawks, and great horned owls were 25 micrograms, 10 micrograms, and 10 micrograms of phytohemagglutinin-P/well, respectively, and 2.5 micrograms, 10 micrograms, and 10 micrograms of concanavalin A/well, respectively. Differences in SI were not seen between the 2 radioactive labels. The optimal concentration of the [3H]thymidine label ranged from 0.06 to 0.125 microCi/well.
The pair correlation function of spatial Hawkes processes
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....
Vagrant western red-shouldered hawks: origins, natal dispersal patterns, and survival
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.
L'univers clos de Stephen Hawking.
Andrillat, H.
Einstein had curved space, Hawking will curve time. Hawking's universe is a closed model, a 4-sphere, which encloses its own space and its own time. Nothing exists outside and without any time overlapping this 4-sphere, it cannot have a beginning, an evolution or an end. It only is. But such an absolute existence of this type of universe implies that its 3-dimensional sclices - which are our physical space - cannot have the same absolute state of being. Thus, they are necessarily transitory, with a beginning and an end, in time which is the 4th remaining dimension of the 4-sphere. Hawking absolute universe is the cause of time.
Retinal pigment epithelial fine structure in the red-tailed hawk (Buto jamaicensis).
Braekevelt, C R
1992-03-01
As part of a comparative morphological study, the fine structure of the retinal epithelium (RPE), choriocapillaris and Bruch's membrane (complexus basalis) has been studied by electron microscopy in the red-tailed hawk (Buteo jamaicensis). In this species the RPE consists of a single layer of low cuboidal cells which display numerous basal (scleral) infoldings and extensive apical (vitreal) processes which interdigitate with photoreceptor outer segments. These epithelial cells are joined laterally by a series of basally located tight junctions. Internally SER is the most abundant cell organelle while only small amounts of RER are present. Polysomes are however abundant as are mitochondria. The RPE cell nucleus is large and vesicular. Melanosomes are mainly located in the apical processes of the RPE cells in light-adaptation. Myeloid bodies are large and numerous in light-adaptation and often show ribosomes on their outer border. Bruch's membrane (complexus basalis) shows the typical pentalaminate structure noted in most vertebrates but with only a poorly defined central elastic layer. The endothelium of the choriocapillaris is very thin facing the RPE but is only moderately fenestrated. The choriocapillaris in this species is unusual however in that many of the fenestrae show a double-layered diaphragm.
Reynolds, M.; Ritchotte, G.; Viggiano, A.; Dwyer, J.; Nielsen, B.; Jacobi, J.D. [Fish and Wildlife Service, Hawaii National Park, HI (United States). Hawaii Research Station
1994-08-01
In 1993, the US Fish and Wildlife Service (USFWS) entered an interagency agreement with the Department of Energy (DOE) to conduct specific biological surveys to identify potential impacts of proposed geothermal development on the biota of the east rift zone of Kilauea volcano in the Puna district on the island of Hawaii. This report presents data on the distribution, habitat use, and density of the Hawaiian hawk or `Io (Buteo solitarius). Data were collected by the USFWS to assess the potential impacts of geothermal development on `Io populations on the island of Hawaii. These impacts include degradation of potential nesting habitat and increased disturbance due to construction and operation activities. Data from these surveys were analyzed as part of an island wide population assessment conducted by the Western Foundation of Vertebrate Zoology at the request of the USFWS.
Origin of Hawking Radiation: Firewall or Atmosphere?
Kim, Wontae
2016-01-01
The Unruh vacuum not admitting any outgoing flux at the horizon implies that the origin of the outgoing Hawking radiation would be the atmosphere of a near-horizon quantum region without resort to the firewall; however, the existence of the firewall of superplanckian excitations at the horizon might be supported by the infinite Tolman temperature of the infinitely blueshifted Hawking temperature at the horizon. Using an exactly soluble model, we show that the firewall necessarily emerges out of the Unruh vacuum such that the Tolman temperature in the Unruh vacuum is divergent in essence due to the infinitely blueshifted negative ingoing flux crossing the horizon rather than the outgoing flux. It is also shown that the outgoing Hawking radiation in the Unruh vacuum indeed originates from the atmosphere, not just at the horizon, which is of no relevance to the infinite blueshift. Consequently, we find that the firewall induced from the infinite Tolman temperature and the Hawking radiation coming from the atmosp...
Comment on Hawking radiation and trapping horizons
Baier, Rudolf
2015-01-01
We consider dynamical black hole formation from a collapsing fluid described by a symmetric and flat FRW metric. Using the Hamilton-Jacobi method the local Hawking temperature for the formed trapping/apparent horizon is calculated. The local Hawking temperature depends on the tunneling path, which we take to be along a null direction $(\\Delta s=0)$. We find that the local Hawking temperature depends directly on the equation of state of the collapsing fluid. We argue that Hawking radiation by quantum tunnelling from future inner and future outer trapping horizons is possible. However, only radiation from a space-like dynamical horizon has a chance to be observed by an external observer. Some comparison to existing literature is made.
Swainson's hawk observations Kern NWR 1991 - 1994
US Fish and Wildlife Service, Department of the Interior — This document describes observations of Swainson's Hawks at Kern NWR and Wildwood Road. It also includes a brief discussion of management strategies to promote...
Hawking radiation from quasilocal dynamical horizons
Ayan Chatterjee
2016-02-01
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.
Black Holes in Hawking's New Theory
Carolyn Johnson; 张凯华
2004-01-01
@@ Stephan Hawking, the physicist, says he was wrong about his long-held idea about black holes, backing off① a theory that had raised the possibility that the collapsed stars were swallowing information and sending it to alternate② universes.
Hawking radiation from a collapsing quantum shell
Pullin, Jorge; Eyheralde, Rodrigo; Gambini, Rodolfo
2017-01-01
We study Hawking radiation from a collapsing shell with uncertainty in its position and momentum. We see there are deviations from the usual spectrum early on in the evolution, tending asymptotically to the usual spectrum plus small corrections.
Hawking's Israel boycott sparks heated response
Dacey, James
2013-06-01
The controversial decision by Stephen Hawking to boycott a prominent conference in Jerusalem in protest against the policies of the Israeli government has provoked strong responses from academics and commentators.
LVIS Integration onto Global Hawk Project
National Aeronautics and Space Administration — Integrate LVIS lidar capability onto the Global Hawk (GH) to enable high altitude mapping of land, vegetation, and ice Provide operational capability and data...
Amplifying the Hawking Signal in BECs
Roberto Balbinot
2014-01-01
Full Text Available We consider simple models of Bose-Einstein condensates to study analog pair-creation effects, namely, the Hawking effect from acoustic black holes and the dynamical Casimir effect in rapidly time-dependent backgrounds. We also focus on a proposal by Cornell to amplify the Hawking signal in density-density correlators by reducing the atoms’ interactions shortly before measurements are made.
Global Hawk Systems Engineering. Case Study
2010-01-01
as Aurora and Grob. Fourteen teams responded. The bids submitted covered a wide-range of size and performance for a $10 million UFP, causing the...Delos Reyes , 95th Air Base Wing Public Affairs, 1 December 2006 Roll Out of Firs Production Block 10 Global Hawk Systems Engineering Case Study...Delos Reyes , 95th DoD News Briefing, June 28, 1995 Air Base Wing Public Affairs, December 1, 2006 Edwards Test Production Global Hawk for Possible
2015-01-01
The family Accipitridae is one of the largest groups of non-passerine birds, including 68 genera and 243 species globally distributed. In the present study, we determined the complete mitochondrial sequences of two species of accipitrid, namely Aquila fasciata and Buteo lagopus, and conducted a comparative mitogenome analysis across the family. The mitogenome length of A. fasciata and B. lagopus are 18,513 and 18,559 bp with an A + T content of 54.2% and 55.0%, respectively. For both the two ...
Bekenstein-Hawking Entropy as Entanglement Entropy
Feng, Yu-Lei
2015-01-01
We show that the Bekenstein-Hawking entropy $S_{BH}$ should be treated as an entanglement entropy, provided that the formation and evaporation of a black hole can be described by quantum unitary evolutions. To confirm this statement, we derive statistical mechanics from quantum mechanics effectively by means of open quantum systems. Then a new definition of Boltzmann entropy for a quantum closed system is given to count microstates in a way consistent with the superposition principle. In particular, this new Boltzmann entropy is a constant that depends only on the dimension of the system's relevant Hilbert subspace. Based on this new definition, some kind of "detailed balance" condition is obtained to stabilize the thermal equilibrium between two macroscopic subsystems within a larger closed system. However, the required "detailed balance" condition between black hole and matter would be broken, if the Bekenstein-Hawking entropy was treated as Boltzmann entropy together with the Hawking temperature as thermal...
Hawking radiation in the kappa-spacetime
Harikumar, E
2016-01-01
In this paper, we analyze the Hawking radiation of kappa-deformed Schwarzchild black hole and obtain the deformed Hawking temperature. For this, we first derive deformed metric for the kappa-spacetime, which in the generic case, is not a symmetric tensor and also has a momentum dependence. We show that the Schwarzchild metric obtained in the kappa-deformed spacetime has a dependence on energy. We use the fact that the deformed metric is conformally flat in the 1+1 dimensions, to solve the kappa-deformed Klein-Gordon equation in the background of the Schwarzchild metric. The method of Boguliobov coefficients is then used to calculate the thermal spectrum of kappa-deformed-Schwarzchild black hole and show that the Hawking temperature is modified by the non-commutativity of the kappa-spacetime.
Hawking radiation without black hole entropy
Visser, M
1998-01-01
In this Letter I point out that Hawking radiation is a purely kinematic effect that is generic to Lorentzian geometries. Hawking radiation arises for any test field on any Lorentzian geometry containing an event horizon regardless of whether or not the Lorentzian geometry satisfies the dynamical Einstein equations of general relativity. On the other hand, the classical laws of black hole mechanics are intrinsically linked to the Einstein equations of general relativity (or their perturbative extension into either semiclassical quantum gravity or string-inspired scenarios). In particular, the laws of black hole thermodynamics, and the identification of the entropy of a black hole with its area, are inextricably linked with the dynamical equations satisfied by the Lorentzian geometry: entropy is proportional to area (plus corrections) if and only if the dynamical equations are the Einstein equations (plus corrections). It is quite possible to have Hawking radiation occur in physical situations in which the laws...
US Fish and Wildlife Service, 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...
US Fish and Wildlife Service, Department of the Interior — Final report of research survey to document the breeding ecology of ferruginous hawks, Swainson’s hawk, and northern harrier in Kulm Wetland Management District...
US Fish and Wildlife Service, Department of the Interior — Final report of research survey to document the breeding ecology of ferruginous hawks, Swainsons hawk, and northern harrier in Kulm Wetland Management District WMD...
Evidence of hawking (falconry) from bird and mammal bones
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
Evidence of hawking (falconry) from bird and mammal bones
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
Stephen Hawking and the universe a biography
Sztajnkrycer, Ben
2012-01-01
ABOUT THE BOOK Stephen William Hawking is arguably the most famous scientist since Albert Einstein. He is a theoretical physicist, applied mathematician, and cosmologist, but he is best known to non-scientists as the author of "A Brief History of Time," his best-selling book that unraveled the origins of the universe. His fame is so far-reaching that he has appeared on such popular entertainment as "Star Trek: The Next Generation" and "Late Night with Conan O'Brien." He has even been animated as a character on "The Simpsons." Hawking is also well known for being the longest-living survivor
On the Mutual Information in Hawking Radiation
Iizuka, Norihiro
2013-01-01
We compute the mutual information of two Hawking particles emitted consecutively by an evaporating black hole. Following Page, we find that the mutual information is of order exp(-S) where S is the entropy of the black hole. We speculate on implications for black hole unitarity, in particular on a possible failure of locality at large distances.
Hawking radiation conference, book of proceedings
Mersini-Houghton, Laura
2016-01-01
Proceedings of the 'Hawking Radiation' conference in Stockholm, Sweden 2015. It includes a link to the video recording of the conference and all the talks, discussions, and communications, that took place during the week of the conference . We hope the recorded discussions will be helpful, especially to the current and future young researchers and students.
Stephen Hawking a life in science
White, Michael
1992-01-01
This biography of the author of "A Brief History of Time", pays particular attention to Hawking's considerable scientific achievement, as well as to the tragic progress of his illnesss and his extraordinary will to survive and to continue working despite major progressive handicap.
Origin of Hawking radiation: firewall or atmosphere?
Kim, Wontae
2017-02-01
The Unruh vacuum not admitting any outgoing flux at the horizon implies that the origin of the outgoing Hawking radiation is the atmosphere of a near-horizon quantum region without resort to the firewall; however, the existence of the firewall of superplanckian excitations at the horizon can be supported by the infinite Tolman temperature at the horizon. In an exactly soluble model, we explicitly show that the firewall necessarily emerges out of the Unruh vacuum so that the Tolman temperature in the Unruh vacuum is divergent in essence due to the infinitely blueshifted negative ingoing flux crossing the horizon rather than the outgoing flux. We also show that the outgoing Hawking radiation in the Unruh vacuum indeed originates from the atmosphere, not just at the horizon, which is of no relevance to the infinite blueshift. Consequently, the firewall from the infinite Tolman temperature and the Hawking radiation from the atmosphere turn out to be compatible, once we waive the claim that the Hawking radiation in the Unruh vacuum originates from the infinitely blueshifted outgoing excitations at the horizon.
Stephen Hawking, Black Holes and Quantum Theory
CatyWeaver; 朱汉昌
2004-01-01
Recently, the physicist Stephen Hawking（斯蒂芬·霍金）had an announcement that made news around the world. Mr. Hawking is the Lucasian.Professor of Mathematics at the University of Cambridge in England. He was in Ireland at the Seventeenth International Conference on General Relativity. This was his announcement: he has changed his mind about black holes.
Krein Quantization Approach to Hawking Radiation
Pejhan, H
2014-01-01
We prove that in the context of Krein method, by applying the results of the accelerated-mirror to a black hole, one can recover the result obtained by Hawking for black hole radiation even considering the fact that vacuum expectation value of the energy-momentum tensor of the free theory is zero.
On the stringy Hartle-Hawking state
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.
Mapping Hawking into Unruh thermal properties
S. Deser; Levin, Orit
1999-01-01
By globally embedding curved spaces into higher dimensional flat ones, we show that Hawking thermal properties map into their Unruh equivalents: The relevant curved space detectors become Rindler ones, whose temperature and entropy reproduce the originals. Specific illustrations include Schwarzschild, Schwarzschild–(anti-)de Sitter, Reissner-Nordström, and Bañados-Teitelboim-Zanelli spaces.
Santos, Tiziano; de Oliveira, Jaqueline B; Vaughan, Christopher; Santiago, Heber
2011-09-01
Successful programs for ex situ and in situ conservation and management of raptors require detailed knowledge about their pathogens. The purpose of this study was to identify the internal parasites of some captive raptors in Mexico, as well as to verify their impact in the health status of infected birds. Birds of prey were confiscated and kept in captivity at the Centro de Investigación y Conservación de Vida Silvestre (CIVS) in Los Reyes La Paz, Mexico State. For this, fecal and blood samples from 74 birds of prey (66 Falconiformes and eight Strigiformes) of 15 species, juveniles and adults from both sexes (39 males and 35 female), were examined for the presence of gastrointestinal and blood parasites. Besides, the oropharyngeal cavity was macroscopically examined for the presence of lesions compatible with trichomoniasis. Among our results we found that lesions compatible with Trichomonas gallinae infection were detected only in two Red-tailed hawks (Buteo jamaicensis) (2.7%); nevertheless, infected birds were in good physical condition. Overall, gastrointestinal parasites were found in 10 (13.5%) raptors: nine falconiforms (13.6%) and one strigiform (12.5%), which mainly presented a single type of gastrointestinal parasite (90%). Eimeria spp. was detected in Harris's hawk (Parabuteo unicinctus), Swainson's hawk (Buteo swainsoni), Red-tailed hawk (B. jamaicensis) and Great horned owl (Bubo virginianus); whereas trematodes eggs were found in Peregrine falcon (Falco peregrinus) and Swainson's hawk (B. swainsoni). Furthermore, eggs of Capillaria spp. were found in one Swainson's hawk (B. swainsoni), which was also infected by trematodes. Hemoprotozoarian were detected in five (6.7%) falconiforms: Haemoproteus spp. in American kestrel (F. sparverius) and Leucocytozoon spp. in Red-tailed hawk (B. jamaicencis). Despite this, no clinical signs referable to gastrointestinal or blood parasite infection were observed in any birds. All parasites identified were recorded
Interactions between a group of Golden Eagles and a herd of North American elk
O'Connell, Matt P.; Kochert, Michael N.
2013-01-01
Raptors are generally considered solitary predators (Schoener 1969), but occasionally they interact socially (Brown and Amadon 1968). Certain raptor species (e.g., Swallow-tailed Kites [Elanoides forficatus] and Swainson's Hawks [Buteo swainsoni]) concentrate in aggregations in response to localized, abundant food sources (Ellis et al. 1993). Many raptor species engage in group hunting (Ellis et al. 1993), and social foraging is a routine strategy for some species (e.g., Harris's Hawks [Parabuteo unicinctus]; Bednarz 1988, Ellis et al. 1993]. Raptors generally engage in group hunting to pursue elusive or large prey (Ellis et al. 1993). Occasionally individuals of conspecific raptors engage in play as a group sometimes involving chases of prey species (Palmer 1988). In this letter, we report interactions between a large group of Golden Eagles and a herd of adult and juvenile Rocky Mountain elk (Cervus canadensis nelsoni) in late autumn.
Tonometry of normal eyes in raptors.
Stiles, J; Buyukmihci, N C; Farver, T B
1994-04-01
An applanation tonometer was used to estimate intraocular pressure in normal eyes of several species of raptors. No bird had active injury or illness, though some were nonreleasable to the wild because of previous injury. Mean (+/- SD) intraocular pressure was 20.6 (+/- 3.4) mm of Hg in red-tailed hawks (Buteo jamaicensis, n = 10), 20.8 (+/- 2.3) mm of Hg in Swainson's hawks (Buteo swainsoni, n = 6), 21.5 (+/- 3.0) mm of Hg in golden eagles (Aquila chrysaetos, n = 7), 20.6 (+/- 2.0) mm of Hg in bald eagles (Haliaeetus leucocephalus, n = 3), and 10.8 (+/- 3.6) mm of Hg in great horned owls (Bubo virginianus, n = 6). There was no significant difference in intraocular pressure between hawks and eagles. Mean pressure in great horned owls was significantly (P < 0.01) lower than pressure in hawks or eagles. Reliable intraocular pressure readings could not be obtained in barn owls (Tyto alba).
Bekenstein-Hawking entropy from Criticality
Bhattacharya, Swastik
2014-01-01
Vacuum Einstein equations when projected on to a black hole horizon is analogous to the dynamics of fluids. In this work we address the question, whether certain properties of semi-classical black holes could be holographically mapped into properties of (2 + 1)-dimensional fluid living on the horizon. In particular, we focus on the statistical mechanical description of the horizon-fluid that leads to Bekenstein-Hawking entropy. Within the paradigm of Landau mean field theory and existence of a condensate at a critical temperature, we explicitly show that Bekenstein-Hawking entropy and other features of black hole thermodynamics can be recovered from the statistical modelling of the fluid. We also show that a negative cosmological constant acts like an external magnetic field that induces order in the system leading to the appearance of a tri-critical point in the phase diagram.
Live trapping of hawks and owls
Stewart, R.E.; Cope, J.B.; Robbins, C.S.
1945-01-01
1. Hawks of six species (80 individuals) and owls of five species (37 individuals) were trapped for banding from November 1, 1943, to. May 26,1944. 2. In general, pole traps proved better than hand-operated traps or automatic traps using live bait. 3. Verbail pole traps proved very efficient, and were much more humane than padded steel traps because they rarely injured a captured bird. 4: Unbaited Verbail traps took a variety of raptors, in rough proportion to their local abundance, although slightly more of beneficial species were caught than of harmful types. 5. Hawks and owls were retrapped more readily in Verbail traps than in other types tried. 6. The number of song birds caught in Verbail traps was negligible. 7. Crows and vultures were not taken in Verbail traps, but possibly could be caught with bait.
2000-01-01
This Broad-Winged Hawk is ready for flight from its perch on a utility pole at Kennedy Space Center. This hawk's habitat is chiefly deciduous woodland, ranging from southern Canada south throughout the eastern United States, including a small area of Central Florida. It winters in tropical South America. The Center shares a boundary with the Merritt Island National Wildlife Refuge, a haven and habitat for more than 331 species of birds. The Refuge encompasses 92,000 acres that are also a habitat for 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.
Hawking radiation and secularly growing loop corrections
Akhmedov, Emil T; Popov, Fedor K
2016-01-01
We study the expectation value of the energy momentum tensor during thin shell collapse for a massive, real, scalar field theory. At tree-level, we find thermal, Hawking-type, behaviour for the energy flux. Using the Schwinger-Keldysh technique, we calculate two-loop corrections to the tree-level correlation functions and show that they exhibit secular growth, suggesting the breakdown of the perturbation theory.
Casimir Effect, Hawking Radiation and Trace Anomaly
Setare, M R
2001-01-01
The Casimir energy for massless scalar field of two parallel conductor, in two dimensional Schwarzchild black hole background, with Dirichlet boundary conditions is calculated by making use of general properties of renormalized stress tensor. We show that vacuum expectation value of stress tensor can be obtain by Casimir effect, trace anomaly and Hawking radiation. Four-dimensional of this problem, by this method, is under progress by this author.
Entropy/information flux in Hawking radiation
Alonso-Serrano, Ana
2015-01-01
Blackbody radiation contains (on average) an entropy of $3.9\\pm2.5$ bits per photon. This applies not only to the proverbial case of "burning a lump of coal", but also to the Hawking radiation from both analogue black holes and general relativistic black holes. The flip side of this observation is the information budget: If the emission process is unitary, (as it certainly is for normal physical/chemical burning, and also for the Hawking emission from analogue black holes), then this entropy is exactly compensated by the "hidden information" in the correlations. We shall now extend this argument to the Hawking radiation from general relativistic black holes, (where previous discussion is both heated and inconclusive), demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget without any hint of a "firewall". The assumption of unitarity instead has a different implication --- the horizon (if present) cannot be an *event* horizon, it must be an *apparent/trapping*...
Hawking radiation a particle physics perspective
Visser, M
1993-01-01
It has recently become fashionable to regard black holes as elementary particles. By taking this suggestion seriously it is possible to cobble together an elementary particle physics based estimate for the decay rate $(\\hbox{black hole})_i \\to (\\hbox{black hole})_f + (\\hbox{massless quantum})$. This estimate of the spontaneous emission rate contains two free parameters which may be fixed by demanding that the high energy end of the spectrum of emitted quanta match a blackbody spectrum at the Hawking temperature. The calculation, though technically trivial, has important conceptual implications: (1) The existence of Hawking radiation from black holes is ultimately dependent only on the fact that massless quanta (and all other forms of matter) couple to gravity. (2) The thermal nature of the Hawking spectrum depends only on the fact that the number of internal states of a large mass black hole is enormous. (3) Remarkably, the resulting formula for the decay rate gives meaningful answers even when extrapolated t...
Electric Shock Injuries in a Harris's Hawk Population
Dwyer, James F.
2006-01-01
Electrocution may be an important agent of mortality in many raptor populations, and has been implicated as a contributing factor in the endangerment of some species. In Tucson, Arizona U.S.A. the electrocution of Harris's Hawks (Parabuteo unicinctus) was reported in both the 1980s and 1990s. The latter report also described Harris's Hawks that survived electric shock injuries. From February 2003-May 2004, I captured and examined wild Harris's Hawks in Tucson to investigate whether electric s...
NASA Global Hawk: A New Tool for Earth Science Research
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.
Notes on breeding sharp-shinned hawks and Cooper’s hawks in Barnwell County, South Carolina.
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.
UH-60M Black Hawk Helicopter (UH-60M Black Hawk)
2016-12-01
Strategy, and the National Defense Strategy. The UH-60M Black Hawk is a digital networked platform with greater range and lift to support maneuver...Critical All All Survivability IR Signature N/A Existing Existing Existing Existing Aircraft Survivability Equipment N/A Existing Existing Existing
Time dependence of Hawking radiation entropy
Page, Don N.
2013-09-01
If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4πM02, or about 7.509M02 ≈ 6.268 × 1076(M0/Msolar)2, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M02 ≈ 1.254 × 1077(M0/Msolar)2, and then decreases back down to 4πM02 = 1.049 × 1077(M0/Msolar)2.
A quasiperiodic Gibbons-Hawking metric and spacetime foam
Nergiz, S; Nergiz, Serdar; Saclioglu, Cihan
1995-01-01
We present a quasiperiodic self-dual metric of the Gibbons--Hawking type with one gravitational instanton per spacetime cell. The solution, based on an adaptation of Weierstrassian \\zeta and \\sigma functions to three dimensions, conforms to a definition of spacetime foam given by Hawking.
Hawking Radiation from Plane Symmetric Black Hole Covariant Anomaly
ZENG Xiao-Xiong; HAN Yi-Wen; YANG Shu-Zheng
2009-01-01
Based on the covariant anomaly cancellation method, which is believed to be more refined than the initial approach of Robinson and Wilczek, we discuss Hawking radiation from the plane symmetric black hole. The result shows that Hawking radiation from the non-spherical symmetric black holes also can be derived from the viewpoint of anomaly.
李同良
2006-01-01
@@ Professor Stephen William Hawking was born on 8 January 1942 in Oxford, England, which is exactly 300 years after the death of Galileo1. From a very early age Hawking showed the qualities2 of a scientist. He was always inquisitive3 and liked to build models to see how things worked.
Delayed response in the Hawk Dove game
Burridge, James; Gao, Yu; Mao, Yong
2017-01-01
We consider a group of agents playing the Hawk-Dove game. These agents have a finite memory of past interactions which they use to optimize their play. By both analytical and numerical approaches, we show that an instability occurs at a critical memory length, and we provide its characterization. We show also that when the game is stable, having a long memory is beneficial but that instability, which may be produced by excessively long memory, hands the advantage to those with shorter memories.
The Hawking Corpuscular Cascading from the Backreacted Black Hole
Övgün, A
2016-01-01
Exciting peculiarities of the Planck scale physics have an immediate effect on the Hawking radiation (HR) from black hole (BH). In this paper, by using the tunneling formalism we determine the Hawking temperature for the vector particles from a backreacted black hole (BBH), which is constructed from the conformal scalar field surrounded by BTZ black hole. Then we extend our calculations for scalar particles with the effect of generalized uncertainty principle (GUP) to understand the effect of quantum gravity. Then we calculate an evaporation time of the BBH, total number of Hawking particles and its quantum corrections. We observe that the remnants in the black hole evaporation are occured and they affect the Hawking temperature of the BBH and also the total number of Hawking particles.
Hawking radiation, the Stefan–Boltzmann law, and unitarization
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.
Lan Jiang
Full Text Available The family Accipitridae is one of the largest groups of non-passerine birds, including 68 genera and 243 species globally distributed. In the present study, we determined the complete mitochondrial sequences of two species of accipitrid, namely Aquila fasciata and Buteo lagopus, and conducted a comparative mitogenome analysis across the family. The mitogenome length of A. fasciata and B. lagopus are 18,513 and 18,559 bp with an A + T content of 54.2% and 55.0%, respectively. For both the two accipitrid birds mtDNAs, obvious positive AT-skew and negative GC-skew biases were detected for all 12 PCGs encoded by the H strand, whereas the reverse was found in MT-ND6 encoded by the L strand. One extra nucleotide'C'is present at the position 174 of MT-ND3 gene of A. fasciata, which is not observed at that of B. lagopus. Six conserved sequence boxes in the Domain II, named boxes F, E, D, C, CSBa, and CSBb, respectively, were recognized in the CRs of A. fasciata and B. lagopus. Rates and patterns of mitochondrial gene evolution within Accipitridae were also estimated. The highest dN/dS was detected for the MT-ATP8 gene (0.32493 among Accipitridae, while the lowest for the MT-CO1 gene (0.01415. Mitophylogenetic analysis supported the robust monophyly of Accipitriformes, and Cathartidae was basal to the balance of the order. Moreover, we performed phylogenetic analyses using two other data sets (two mitochondrial loci, and combined nuclear and mitochondrial loci. Our results indicate that the subfamily Aquilinae and all currently polytypic genera of this subfamily are monophyletic. These two novel mtDNA data will be useful in refining the phylogenetic relationships and evolutionary processes of Accipitriformes.
Jiang, Lan; Chen, Juan; Wang, Ping; Ren, Qiongqiong; Yuan, Jian; Qian, Chaoju; Hua, Xinghong; Guo, Zhichun; Zhang, Lei; Yang, Jianke; Wang, Ying; Zhang, Qin; Ding, Hengwu; Bi, De; Zhang, Zongmeng; Wang, Qingqing; Chen, Dongsheng; Kan, Xianzhao
2015-01-01
The family Accipitridae is one of the largest groups of non-passerine birds, including 68 genera and 243 species globally distributed. In the present study, we determined the complete mitochondrial sequences of two species of accipitrid, namely Aquila fasciata and Buteo lagopus, and conducted a comparative mitogenome analysis across the family. The mitogenome length of A. fasciata and B. lagopus are 18,513 and 18,559 bp with an A + T content of 54.2% and 55.0%, respectively. For both the two accipitrid birds mtDNAs, obvious positive AT-skew and negative GC-skew biases were detected for all 12 PCGs encoded by the H strand, whereas the reverse was found in MT-ND6 encoded by the L strand. One extra nucleotide'C'is present at the position 174 of MT-ND3 gene of A. fasciata, which is not observed at that of B. lagopus. Six conserved sequence boxes in the Domain II, named boxes F, E, D, C, CSBa, and CSBb, respectively, were recognized in the CRs of A. fasciata and B. lagopus. Rates and patterns of mitochondrial gene evolution within Accipitridae were also estimated. The highest dN/dS was detected for the MT-ATP8 gene (0.32493) among Accipitridae, while the lowest for the MT-CO1 gene (0.01415). Mitophylogenetic analysis supported the robust monophyly of Accipitriformes, and Cathartidae was basal to the balance of the order. Moreover, we performed phylogenetic analyses using two other data sets (two mitochondrial loci, and combined nuclear and mitochondrial loci). Our results indicate that the subfamily Aquilinae and all currently polytypic genera of this subfamily are monophyletic. These two novel mtDNA data will be useful in refining the phylogenetic relationships and evolutionary processes of Accipitriformes.
Hawking radiation inside a Schwarzschild black hole
Hamilton, Andrew J S
2016-01-01
The boundary of any observer's spacetime is the boundary that divides what the observer can see from what they cannot see. The boundary of an observer's spacetime in the presence of a black hole is not the true (future event) horizon of the black hole, but rather the illusory horizon, the dimming, redshifting surface of the star that collapsed to the black hole long ago. The illusory horizon is the source of Hawking radiation seen by observers both outside and inside the true horizon. The perceived acceleration (gravity) on the illusory horizon sets the characteristic frequency scale of Hawking radiation, even if that acceleration varies dynamically, as it must do from the perspective of an infalling observer. The acceleration seen by a non-rotating free-faller both on the illusory horizon below and in the sky above is calculated for a Schwarzschild black hole. Remarkably, as an infaller approaches the singularity, the acceleration becomes isotropic, and diverging as a power law. The isotropic, power-law char...
Plumage polymorphism and fitness in Swainson's hawks.
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.
2000-01-01
At KSC, a red-tailed hawk waits on top of a utility pole for the slightest movement in the grass below. It feeds mostly on small rodents. Ranging in height from 18 inches to 25 inches, the species has a stocky build with a whitish breast and rust-colored tail. It has a high-pitched descending scream with a hoarse quality. The hawk inhabits mainly deciduous forest and adjacent open country from Alaska and Nova Scotia south to Panama. KSC shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.
Hawking radiation as perceived by different observers
Barbado, Luis C; Garay, Luis J
2011-01-01
We use a method recently introduced in Barcel\\'o et al, arXiv:1011.5593 [gr-qc] to analyse Hawking radiation in a Schwarzschild black hole as perceived by different observers in the system. The method is based on the introduction of an "effective temperature" function that varies with time. First we introduce a non-stationary vacuum state for a quantum scalar field, which interpolates between the Boulware vacuum state at early times and the Unruh vacuum state at late times. In this way we mimic the process of switching on Hawking radiation in realistic collapse scenarios. Then, we analyse this vacuum state from the perspective of static observers at different radial positions, observers undergoing a free-fall trajectory from infinity, and observers standing at rest at a radial distance and then released to fall freely towards the horizon. The physical image that emerges from these analyses is rather rich and compelling. Among many other results, we find that generic freely-falling observes do not perceive vac...
Time Dependence of Hawking Radiation Entropy
Page, Don N
2013-01-01
If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4 pi M_0^2, or about 7.509 M_0^2 \\approx 6.268\\times 10^{76}(M_0/M_\\odot)^2, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the...
Hawking radiation from magnetized Kerr-Newman black hole
Rizwan, Muhammad; Saifullah, K.
2016-12-01
Hawking radiation of charged scalar and Dirac particles from the event horizon of magnetized Kerr-Newman black holes is studied using the Hamilton-Jacobi method and WKB approximation. This is done by calculating tunneling probabilities of these particles from the horizons of magnetized black holes. This method yields the Hawking temperature of magnetized Kerr-Newman black holes as well. It is interesting to note that while the tunneling probabilities depend upon the background magnetic field, the Hawking temperature is not affected by magnetization.
Landauer Transport Model for Hawking Radiation from a Black Hole
Nation, P D; Nori, Franco
2010-01-01
We investigate the Hawking radiation energy and entropy flow rates from a black hole viewed as a one-dimensional (1D) Landauer transport process. The conformal symmetry in the near-horizon region leads directly to radiation rates that are identical to those of a single 1D quantum channel connected to a thermal reservoir at the Hawking temperature. The particle statistics independence of the 1D energy and entropy currents is applied to a black hole radiating into vacuum as well as one near thermal equilibrium with its environment. The Hawking radiation entropy production ratio is also examined.
英诗Hawk Roosting的主位结构及特点%The thematic structure features of Hawk Roosting
许耘
2008-01-01
一个句子或小句表达信息的起点是主位,围绕主位加以叙述发展的部分是叙位.主位传递的是已知信息,叙位传递的是新信息.在hawk roosting中,出现频率最高的主位是I,全诗虽没有出现一个点题的Hawk(鹰)字眼,但这个第一人称代词实际上指的就是Hawk.
The theory of Hawking radiation in laboratory analogues
Robertson, Scott
2015-01-01
Hawking radiation, despite being known to theoretical physics for nearly forty years, remains elusive and undetected. It also suffers, in its original context of gravitational black holes, from practical and conceptual difficulties. Of particular note is the trans-Planckian problem, which is concerned with the apparent origin of the radiation in absurdly high frequencies. In order to gain better theoretical understanding and, it is hoped, experimental verification of Hawking radiation, much study is being devoted to laboratory systems which use moving media to model the spacetime geometry of black holes, and which, by analogy, are also thought to emit Hawking radiation. These analogue systems typically exhibit dispersion, which regularizes the wave behaviour at the horizon at the cost of a more complicated theoretical framework. This tutorial serves as an introduction to Hawking radiation and its analogues, developing the moving medium analogy for black holes and demonstrating how dispersion can be incorporat...
Rotating embedded black holes: Entropy and Hawking's radiation
2004-01-01
In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.
GUP assisted Hawking radiation of rotating acoustic black holes
Sakalli, I.; Övgün, A.; Jusufi, K.
2016-10-01
Recent studies (Steinhauer in Nat. Phys. 10:864, 2014, Phys. Rev. D 92:024043, 2015) provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
Stephen Hawking ja tema kuulsad kihlveod / Andi Hektor
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
GUP Assisted Hawking Radiation of Rotating Acoustic Black Holes
Sakalli, I; Jusufi, K
2016-01-01
Recent studies [J. Steinhauer, Nature Phys., $\\textbf{10}$, 864 (2014); Phys. Rev. D $\\textbf{92}$, 024043 (2015)] provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
Hawking Temperature of an Arbitrarily Accelerating Black Hole
Wei-Zhen Pan; Wei Liu
2014-09-01
Hawking temperature of an arbitrarily accelerating black hole with electric and magnetic charges are obtained based on the Klein–Gordon equation with a correct-dimension new tortoise coordinate transformation.
End Point of Hawking Evaporation -- Case of Integrable Model
Hotta, M
1994-01-01
Quantum back reaction due to $N$ massless fields may be worked out to a considerable detail in a variant of integrable dilaton gravity model in two dimensions. It is shown that there exists a critical mass of collapsing object of order $\\hbar N \\times$ (cosmological constant)$^{1/2}$, above which the end point of Hawking evaporation is two disconnected remnants of infinite extent, each separated by a mouth from the outside region. Deep inside the mouth there is a universal flux of radiation in all directions, in a form different from Hawking radiation. Below the critical mass no remnant is left behind, implying complete Hawking evaporation or even showing no sign of Hawking radiation. Existence of infinitely many static states of quantum nature is also demonstrated in this model.
Questioning the recent observation of quantum Hawking radiation
Leonhardt, Ulf
2016-01-01
A recent paper [J. Steinhauer, doi:10.1038/nphys3863, arXiv:1510.00621] has claimed the observation of quantum Hawking radiation and its entanglement in an analogue black hole. However, while the author has achieved an extraordinary experimental feat, the claims of the paper do not stand up to scrutiny: they are not sufficiently supported by evidence, are obtained with biased methods and violate hard theoretical bounds, which raises severe doubts on the observation of Hawking radiation.
Non-thermal Hawking radiation from the Kerr black hole
HAN Yi-Wen; HAO Jia-Bo
2009-01-01
We present a short and direct derivation of Hawking radiation by using the Damour-Ruffini method, as taking into account the self-gravitational interaction from the Kerr black hole. It is found that the radiation is not exactly thermal, and because the derivation obeys conservation laws, the non-thermal Hawking radiation can carry information from the black hole. So it can be used to explain the black hole information paradox, and the process satisfies unitary.
Hawking radiation of a uniformly accelerating black hole
Ren Jun; Cao Jiang-Ling; Zhao Zheng
2006-01-01
In this paper, we study the Hawking radiation via tunnelling from a uniformly accelerating black hole. Although the Bekenstein-Hawking entropy is proportional also to the area of the event horizon, the radius of it, rH, is a function of θ, which leads to the difficulties in the calculation of the emission rate. In order to overcome the mathematical difficulties, we propose a new technique to calculate the emission rate and the result obtained is reasonable.
Street Hawking: Oppressing the Girl Child or Family Economic Supplement?
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…
Hawking receives top US award at White House
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".
Corrected Hawking Temperature in Snyder's Quantized Space-time
Ma, Meng-Sen; Liu, Fang; Zhao, Ren
2015-06-01
In the quantized space-time of Snyder, generalized uncertainty relation and commutativity are both included. In this paper we analyze the possible form for the corrected Hawking temperature and derive it from the both effects. It is shown that the corrected Hawking temperature has a form similar to the one of noncommutative geometry inspired Schwarzschild black hole, however with an requirement for the noncommutative parameter 𝜃 and the minimal length a.
Anomaly Analysis of Hawking Radiation from Acoustic Black Hole
Kim, Wontae
2007-01-01
The Hawking radiation from the three dimensional rotating acoustic black hole is considered from the viewpoint of anomaly cancellation method initiated by Robinson and Wilczek. Quantum field near the horizon is effectively described by two dimensional charged field with a charge identified as the angular momentum m. The fluxes of charge and energy are obtained from the anomaly cancellation condition and regularity at the horizon, and are shown to match with those of the two dimensional black body radiation at the Hawking temperature.
Equivalence of the Hawking temperature in conformal frames
Marques, Glauber Tadaiesky [Universidade Federal Rural da Amazonia-Brazil, ICIBE-LASIC, Belem/PA (Brazil); Rodrigues, Manuel E. [Universidade Federal do Espirito Santo, Centro de Ciencias Exatas, Departamento de Fisica, Vitoria/ES (Brazil)
2012-02-15
The conformal invariance of the Hawking temperature, conjectured for the asymptotically flat and stationary black holes by Jacobson and Kang, is semiclassically evaluated for a simple particular case of symmetrical spherically and non-asymptotically flat black hole. By using the Bogoliubov coefficients, the metric euclideanization, the reflection coefficient and the gravitational anomaly, as methods of calculating the Hawking temperature, we find that it is invariant under a specific conformal transformation of the metric. We briefly discuss the results for each method. (orig.)
Hélène Mialet, Hawking Incorporated. Stephen Hawking and the Anthropology of the Knowing subject
Popescu, Cristina
2013-01-01
Situé dans la tradition de recherche développée autour de la théorie de l’acteur-réseau (actor-network theory), le livre de Hélène Mialet choisit d’explorer la figure particulière du physicien anglais Stephen Hawking. À travers sept chapitres complémentaires, le lecteur découvre à la fois « Hawking l’individu » et « Hawking le génie en physique ». C’est une distinction qui ne paraît pas toute de suite évidente au non-initié, mais, nous allons le comprendre rapidement, le Hawking des médias, n...
Tucker, V A
2000-12-01
Raptors - falcons, hawks and eagles in this study - such as peregrine falcons (Falco peregrinus) that attack distant prey from high-speed dives face a paradox. Anatomical and behavioral measurements show that raptors of many species must turn their heads approximately 40 degrees to one side to see the prey straight ahead with maximum visual acuity, yet turning the head would presumably slow their diving speed by increasing aerodynamic drag. This paper investigates the aerodynamic drag part of this paradox by measuring the drag and torque on wingless model bodies of a peregrine falcon and a red-tailed hawk (Buteo jamaicensis) with straight and turned heads in a wind tunnel at a speed of 11.7 m s(-)(1). With a turned head, drag increased more than 50 %, and torque developed that tended to yaw the model towards the direction in which the head pointed. Mathematical models for the drag required to prevent yawing showed that the total drag could plausibly more than double with head-turning. Thus, the presumption about increased drag in the paradox is correct. The relationships between drag, head angle and torque developed here are prerequisites to the explanation of how a raptor could avoid the paradox by holding its head straight and flying along a spiral path that keeps its line of sight for maximum acuity pointed sideways at the prey. Although the spiral path to the prey is longer than the straight path, the raptor's higher speed can theoretically compensate for the difference in distances; and wild peregrines do indeed approach prey by flying along curved paths that resemble spirals. In addition to providing data that explain the paradox, this paper reports the lowest drag coefficients yet measured for raptor bodies (0.11 for the peregrine and 0.12 for the red-tailed hawk) when the body models with straight heads were set to pitch and yaw angles for minimum drag. These values are markedly lower than value of the parasite drag coefficient (C(D,par)) of 0.18 previously
Hawking Incorporated Stephen Hawking and the Anthropology of the Knowing Subject
Mialet, Hélène
2012-01-01
These days, the idea of the cyborg is less the stuff of science fiction and more a reality, as we are all, in one way or another, constantly connected, extended, wired, and dispersed in and through technology. One wonders where the individual, the person, the human, and the body are-or, alternatively, where they stop. These are the kinds of questions Hélène Mialet explores in this fascinating volume, as she focuses on a man who is permanently attached to assemblages of machines, devices, and collectivities of people: Stephen Hawking. Drawing on an extensive and in-depth series of interviews wi
Bekenstein-Hawking Entropy and Strange Metals
Sachdev, Subir
2015-01-01
We examine models of fermions with infinite-range interactions which realize non-Fermi liquids with a continuously variable U(1) charge density $\\mathcal{Q}$, and a non-zero entropy density $\\mathcal{S}$ at vanishing temperature. Real time correlators of operators carrying U(1) charge $q$ at a low temperature $T$ are characterized by a $\\mathcal{Q}$-dependent frequency $\\omega_{\\mathcal{S}} = (q \\, T/\\hbar) (\\partial \\mathcal{S}/\\partial{\\mathcal{Q}})$ which determines a spectral asymmetry. We show that the correlators match precisely with those of the AdS$_2$ horizons of extremal charged black holes. On the black hole side, the matching requires $\\mathcal{S}$ to be equal to the Bekenstein-Hawking entropy density, and employs the laws of black hole thermodynamics which relate $(\\partial{\\mathcal{S}}/\\partial{\\mathcal{Q}})/(2 \\pi)$ 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.
Why Hawking Radiation Cannot Be Decoded
Ong, Yen Chin; Chen, Pisin
2014-01-01
One of the great difficulties in the theory of black hole evaporation is that the most decisive phenomena tend to occur when the black hole is extremely hot: that is, when the physics is most poorly understood. Fortunately, a crucial step in the Harlow-Hayden approach to the firewall paradox, concerning the time available for decoding of Hawking radiation emanating from charged AdS black holes, can be made to work without relying on the unknown physics of black holes with extremely high temperatures; in fact, it relies on the properties of cold black holes. Here we clarify this surprising point. The approach is based on ideas borrowed from applications of the AdS/CFT correspondence to the quark-gluon plasma. Firewalls aside, our work presents a detailed analysis of the thermodynamics and evolution of evaporating charged AdS black holes with flat event horizons. We show that, in one way or another, these black holes are always eventually destroyed in a time which, while long by normal standards, is short relat...
Should we terminate an 'artificial,' tree-nesting raptor population in Arizona?
Ellis, D.H.; Smith, D.G.; Trahan, F.B.P.
1994-01-01
The Altar Valley in southcentral Arizona was once a iallgrass prairie. Overgrazing prevented fire and spread mesquite, allowing the area, now a savanna, to be heavily used by tree-nesting raptors in summer and heavily hunted by perch-hunting raptors in winter. The breeding raptor community (over 150 pairs) consists primarily of red-tailed hawks (Buteo jamaicensis), great horned owls (Bubo virginianus), and Swainson's hawks (Buteo swainsoni). Common ravens (Corvus corax) are also common and there is a recently discovered small population of black-shouldered kites (Elanus caeruleus). Recent efforts to restore the endangered masked bobwhite (Colinus virginianus) to the area clash with habitat needs of the raptors. This conflict focuses attention on the 'multiple use' concept and calls for implementation of a 'prime use' or 'highest and best use' management strategy. Prime use (this is the only area in the United States managed for the masked bobwhite) 'will likely call for the removal of trees over much of the Altar Valley. This removal will likely result in the nearly total loss of nesting and perching sites for breeding, migrating, and wintering raptors.
Hawking radiation, the Stefan–Boltzmann law, and unitarization
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.
Hawking radiation of five-dimensional charged black holes with scalar fields
Miao, Yan-Gang; Xu, Zhen-Ming
2017-09-01
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.
Hawking Temperature of a Static Black Hole in Harmonic Coordinates
He, Guan-Sheng; Lin, Wei-Bin
2015-12-01
Hawking radiation is usually studied in standard coordinates. In this paper, we calculate the Hawking temperature of a Schwarzschild black hole in harmonic coordinates, as well as that of a Reissner-Nordström black hole. The action of a scalar field near the event horizon can be formulated exactly without omitting some high-order terms. We show dimensional reduction for Hawking temperature is also valid for harmonic coordinates, and verify further that the results are independent on concrete coordinates. With the help of Lorentz transformation, our work might also serve as a basis to investigate the thermal radiation from a moving black hole. Supported in part by the Ph.D. Programs Foundation of Ministry of Education of China under Grant No. 20110184110016, the National Basic Research Program of China (973 Program) Grant No. 2013CB328904, and the Fundamental Research Funds for the Central Universities under Grant No. 2682014ZT32
Hawking radiation of non-asymptotically flat rotating black holes
Sakalli, Izzet; Aslan, Onur Atilla
2016-04-01
We study the Hawking radiation of non-asymptotically flat rotating linear dilaton black holes, which are the solutions to the 4D Einstein-Maxwell-dilaton-axion action by using the semi-classical radiation spectrum method. Using scalar perturbations, we show that both angular and radial equations produce exact analytical solutions. Thus, we obtain a precise radiation spectrum for the rotating linear dilaton black hole. The high-frequency regime does not yield the standard Hawking temperature of this black hole computed from the surface gravity. However, we show in detail that the specific low-frequency band of the radiation spectrum allows for the original Hawking temperature of the rotating linear dilaton black hole. The computations are also exhibited graphically.
Hawking Modes And The Optimal Jumbler: Lessons On Unitarity
Koohbor, Javad; Tavanfar, Alireza
2015-01-01
Based on an 'observer-centric methodology' which is conceptually and operationally most direct, we pinpoint the most basic origin of the spectral Planckianity of the asymptotic Hawking modes, which is generic to the conventional treatments of the evolving horizons. Analyzing spacetimes marked by the sole virtue of possessing causal horizons, we clarify in details how this spectral Planckianity is geometrically imposed on the exponentially-redshifted propagating Hawking modes through a 'holographically-illicit' 'jumbling mechanism' which is developed by an environment of the 'curvature modes' in the causal patch of the asymptotic observer. We verify that this mechanism is stable under broad variations of geometries, topologies and categories of the causal horizons, in all the Minkoswki, dS and AdS asymptotics. In the continuation, we elucidate the underlying microscopic physics of the actual phenomenon of the Hawking evaporation of causal horizons. The description is based on a novel holographic scheme of grav...
A 38-year Summary of Raptor Banding at Hawk Ridge, Duluth, Minnesota, USA
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...
Abundance of diurnal raptors on open space grasslands in an urbanized landscape
Berry, M.E.; Bock, C.E.; Haire, S.L.
1998-01-01
We conducted point counts of diurnal raptors on Boulder, Colorado, grasslands for three winters and summers, and compared results to landscape features of the count areas. Four wintering species were scarce on plots that included significant amounts of urban habitat, with a critical landscape threshold at about 5-7% urbanization: Bald Eagle (Haliaeetus leucocephalus), Ferruginous Hawk (Buteo regalis), Rough-legged Hawk (B. lagopus), and Prairie Falcon (Falco mexicanus). Counts of the first three species also were positively correlated with proximity of the count plots to the nearest colony of black-tailed prairie dogs (Cynomys ludovicianus). Two breeding species, the Red-tailed Hawk (B. jamaicensis) and Swainson's Hawk (B. swainsoni), were more abundant on plots dominated by lowland hayfields and tallgrass prairies, as opposed to upland mixed and shortgrass prairies. They, along with the ubiquitous American Kestrel (Falco sparverius), were not sensitive to the amounts of urbanization (up to 30%) that occurred in the landscapes sampled. Results of this study suggest that urban open space grasslands can support sizable populations of most diurnal raptors, as long as prey populations persist, but that some species are highly sensitive to landscape urbanization.
Fairness and Reciprocity in the Hawk-Dove Game
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....
Cyanide poisoning of a Cooper’s hawk (Accipiter cooperii)
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.
Tunnelling Effect and Hawking Radiation from a Vaidya Black Hole
ZHANG Jing-Yi; ZHAO Zheng
2006-01-01
@@ We extend Parikh's study to the non-stationary black hole. As an example of the non-stationary black hole, we investigate the tunnelling effect and Hawking radiation from a Vaidya black hole whose Bondi mass is identical to its mass parameter. The Hawking radiation is considered as a tunnelling process across the event horizon and we calculate the tunnelling probability. It is found that the result is different from Parikh's study because drH/dv is the function of Bondi mass m(v).
Hawking radiation with dispersion: the broadened horizon paradigm
Coutant, Antonin
2014-01-01
We study the spatial properties of the modes responsible for the Hawking effect in the presence of high frequency dispersion. Near the horizon, the modes are regularized on a small distance which only depends on the surface gravity and the scale of dispersion. The regularization explains why the spectrum is hardly affected by dispersion as long as the background geometry does not significantly vary over this composite length. For relevant frequencies, the regularization differs from the usual WKB resolution of wave singularity near a turning point. The latter only applies when the frequency is so high that the Hawking effect is negligible.
Quantum Signature of Analog Hawking Radiation in Momentum Space.
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.
Hawking radiation from gravity's rainbow via gravitational anomaly
Zeng Xiao-Xiong; Yang Shu-Zheng; Chen De-You
2008-01-01
Based on the anomaly cancellation method,initiated by Robinson and Wilczek,we investigates Hawking radiation from the modified Schwarzschild black hole from gravity's rainbow from the anomaly point of view.Unlike the general Schwarzschild space-time,the metric of this black hole depends on the energies of probes.The obtained result shows to restore the underlying general covariance at the quantum level in the effective field,the covariant compensating flux of energy-momentum tensor,which is related to the energies of the probes,should precisely equal to that of a (1+1)-dimensional blackbody at the Hawking temperature.
Dirac Particles' Hawking Radiation from a Schwarzschild Black Hole
HE Xiao-Kai; LIU Wen-Biao
2007-01-01
@@ Considering energy conservation and the backreaction of particles to spacetime, we investigate the massless/massive Dirac particles' Hawking radiation from a Schwarzschild black hole. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the results obtained before. It satisfies the underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas the improved Damour-Ruffini method is more concise and understandable.
On the remote sensing of Hawking grey pulses
Rosu, H. C.
1994-01-01
This is a short note on the black hole remote-sensing problem, i.e., finding out `surface' temperature distributions of various types of small (micron-sized) black holes from the spectral measurements of their Hawking grey pulses. Chen's modified Moebius inverse transform is illustrated in this context
Kas inimkond näeb aastat 2106? / Stephen Hawking
Hawking, Stephen W., 1942-
2006-01-01
Briti füüsik Stephen Hawking avas Yahoo! internetifoorumis debati, küsides foorumikasutajatelt: "Maailmas valitseb poliitiline, sotsiaalne ja ökoloogiline kaos - kuidas suudab inimkond järgmised sada aastat üle elada?". Kommenteerivad julgeolekuekspert Eerik-Niiles Kross, meditsiiniteaduste doktor Mari Järvelaid ja keskkonnaekspert Marek Strandberg
Global Hawk Pacific (GloPac) COA and Mission Coordination
Dillon, Mark; Hall, Philip
2010-01-01
This slide presentation reviews the science objectives of the Global Hawk unmanned aircraft system (UAS) in the Pacific region, shows examp le flight tracks, the satellite under-flight requirement, the flight planning, and the agencies coordination of the airspace required for the Certificate of Authorization (COA).
Black Hawk. The Story of an American Indian.
Cunningham, Maggi
Born in 1767, Black Hawk was the last great war leader of the Sauk Indians, who lived in the Rock River valley in Illinois. By age 25, he was a famed warrior and leader of his people who raided neighboring tribes until a period of peace and prosperity began about 1800. Various treaties of which the Sauk knew and understood very little deprived the…
Kas inimkond näeb aastat 2106? / Stephen Hawking
Hawking, Stephen W., 1942-
2006-01-01
Briti füüsik Stephen Hawking avas Yahoo! internetifoorumis debati, küsides foorumikasutajatelt: "Maailmas valitseb poliitiline, sotsiaalne ja ökoloogiline kaos - kuidas suudab inimkond järgmised sada aastat üle elada?". Kommenteerivad julgeolekuekspert Eerik-Niiles Kross, meditsiiniteaduste doktor Mari Järvelaid ja keskkonnaekspert Marek Strandberg
Hawking-Hayward quasi-local energy under conformal transformations
Prain, Angus; Faraoni, Valerio; Lapierre-Léonard, Marianne
2015-01-01
We derive a formula describing the transformation of the Hawking-Hayward quasi-local energy under a conformal rescaling of the spacetime metric. A known formula for the transformation of the Misner-Sharp-Hernandez mass is recovered as a special case.
Hawking radiation via tunnelling from general stationary axisymmetric black holes
Zhang Jing-Yi; Fan Jun-Hui
2007-01-01
Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated,separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.
Comment on 'Hawking radiation from fluctuating black holes'
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
Ambiguity of the equivalence principle and Hawking's temperature
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
Hawking Radiation via Tunnelling from Arbitrarily Dimensional Schwarzschild Black Holes
REN Jun; ZHAO Zheng; GAO Chang-Jun
2005-01-01
@@ We extend Parikh's recent work to the arbitrarily dimensional Schwarzschild black holes whose Arnowitt-DeserMisner (ADM) mass is identical to its mass parameter. We view Hawking radiation as a tunnelling process across the event horizon. From the tunnelling probability we also find a leading correction to the semiclassical emission rate. The result consists with an underlying unitary theory.
Stephen Hawking bags big new 3m physics prize
Johnston, Hamish
2013-01-01
A massive 3m in prize money has gone to the British cosmologist Stephen Hawking for his work on black holes, quantum gravity and the early universe. The award is one of two "special fundamental physics prizes" from the Fundamental Physics Prize Foundation, which was set up earlier this year by the Russian physicist-turned-entrepreneur Yuri Milner.
The Captivity Narrative as Propaganda in the Black Hawk War.
Fisher, Darlene E.
1987-01-01
Shows how captivity stories acted as propaganda against the American Indians in the nineteenth century. Gives excerpts from a captivity narrative portraying Indians in a negative way and demonstrates its use as propaganda during the time of the Black Hawk War. (AEM)
On Hawking Radiation of 3D Rotating Hairy Black Holes
Belhaj, A; Moumni, H EL; Masmar, K; Sedra, M B
2015-01-01
We study the Hawking radiation of 3D rotating hairy black holes. More concretely, we compute the transition probability of a bosonic and fermionic particle in such backgrounds. Thew, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hair B and the rotation parameter a control such a probability.
Hawking's singularity theorem for $C^{1,1}$-metrics
Kunzinger, Michael; Stojkovic, Milena; Vickers, James A
2014-01-01
We provide a detailed proof of Hawking's singularity theorem in the regularity class $C^{1,1}$, i.e., for spacetime metrics possessing locally Lipschitz continuous first derivatives. The proof uses recent results in $C^{1,1}$-causality theory and is based on regularisation techniques adapted to the causal structure.
Kajian Kritis Terhadap Praanggapan Metafisis-Epistemologis Kosmologi Stephen Hawking
2008-01-01
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...
Supplier Education--Deere & Company Partners with Black Hawk College.
Lundquist, Linda
1997-01-01
Describes the partnership between Deere & Company and Black Hawk College that provided a training program for John Deere suppliers, resulting in a cost-effective approach to upgrading supplier skills and improving Deere product quality. Lists benefits of supplier development and training. (YKH)
The Javan Hawk-eagle : misconceptions about rareness and threat
Balen, van S.; Nijman, V.; Prins, H.H.T.
2000-01-01
The Javan hawk-eagle (Spizaetus bartelsi) is a threatened raptor endemic to the densely populated island of Java. Historically very little is known about its biology. Recent surveys showed that the population size has been underestimated in the past. The breeding population is estimated to be
Lead in hawks, falcons and owls downstream from a mining site on the Coeur D'Alene river, Idaho
Henny, C.J.; Blus, L.J.; Hoffman, D.J.; Grove, R.A.
1994-01-01
Mining and smelting at Kellogg-Smelterville, Idaho, resulted in high concentrations of lead in Coeur d'Alene (CDA) River sediments and the floodplain downstream, where American Kestrels (Falco sparverius), Northern Harriers (Circus cyaneus), Red-tailed Hawks (Buteo jamaicensis), Great Horned Owls (Bubo virginianus), and Western Screech-owls (Otus kennicotti) nested. Nestling American Kestrels contained significantly higher (P=0.0012) blood lead concentrations along the CDA River (0.24 ?g/g, wet wt) than the nearby reference area (0.087 ?g/g). A 35% inhibition of blood *-aminolevulinic acid dehydratase (ALAD) in nestling Northern Harriers (P=0.0001), 55% in nestling American Kestrels (P=0.0001) and 81% in adult American Kestrels (P=0.0004) provided additional evidence of lead exposure in the CDA River population. In nestling American Kestrels and Northern Harriers, ALAD activity was negatively correlated with lead in blood. An earlier report on Ospreys (Pandion haliaetus) showed slightly less inhibition of ALAD than in American Kestrels, but no significant reduction in hemoglobin or hematocrit and no negative influence on production rates. The adult and nestling American Kestrels along the CDA River contained about twice as much blood lead as Ospreys during the same years (adult 0.46 vs. 0.20 ?g/g, and nestling 0.24 vs. 0.09 ?g/g), but adults showed a 7.5% reduction in hemoglobin (P=0.0356) and nestlings an 8.2% reduction in hemoglobin (P=0.0353) and a 5.8% reduction in hematocrit (P=0.0482). We did not observe raptor deaths related to lead, and although the production rate for American Kestrels was slightly lower along the CDA River, we found no significant negative relation between productivity and lead. Limited data on the other raptors provide evidence of exposure to lead along the CDA River. Several traits of raptors apparently reduce their potential for accumulating critical levels of lead which is primarily stored in bones of prey species.
Fuller, Mark R.
2013-01-01
The project was undertaken because of a paucity of information about the possible effects of OG operations and resource management on nesting raptors. BLM raptor management has included stipulations that restricted human activity near raptor nests during the raptor nesting season. The BLM and the Department of Energy (DOE), which provided financial support for the study, seek information that will contribute to enhancing OG extraction operations while providing environmental protection, including raptor conservation. This project used historical data from Utah and Wyoming. The Price, Utah study area, as of 2006, contained more than 1,100 wells, in a nearly uniform distribution at a density of one per quarter section (160-acre spacing). Some development occurred closer to existing nests because the nest sites had not been discovered or because the land is administered by the State of Utah, without these stipulations. The Rawlins, Wyoming study area included more than 4,200 OG wells in 2006. Compared to the Price study area, wells at Rawlins were less regularly distributed; reaching densities of one well per quarter section (160-acre spacing) in some areas, but less dense elsewhere. HWI compiled information from federal bureaus, state agencies, and industry, and determined how to evaluate the effectiveness of spatial and temporal buffer restrictions that have been applied within areas of OG extraction. HWI used the historical data to describe patterns of OG development relative to raptor nests, and to document changes in the distribution and breeding status of raptor nests relative to OG activities. HWI evaluated how these historical datasets were useful for quantifying the relationship between OG development and other human activities and nesting raptors. HWI assessed changes in Ferruginous Hawk (Buteo regalis) nesting success and productivity, and in use of artificial nest structures (ANSs), which had been erected to reduce the use by raptors of OG structures as
Parsons, Paul; Dixon, Gail
2013-09-01
3-minutes Stephen Hawking offers a compact introduction to life and work of this impressing scientist. This book is devided into three parts: Hawking's life, his theories, his influence. Each part offers fascinating reading material for one hour. The partial themes of this book are served up in practical 3-minute portions.
Hawk-Eyes on Science and in Space
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.
Conference | From Newton to Hawking and beyond | 28 May
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...
Correction value to charged Bekenstein-Hawking black hole entropy
2008-01-01
Recently,based on the study of black hole Hawking radiation with the tunnel effect method,we found that the radiation spectrum of the black hole is not a strict pure thermal spectrum. It is a very interesting problem to determine how the departure of the black hole radiation spectrum from the pure thermal spectrum affects entropy. We calculate the partition function by the energy spectrum obtained using tunnel effect. Using the relation between the partition function and entropy,we derive the correction value to Bekenstein-Hawking entropy of the charged black hole. Fur-thermore,we obtain the conditions that various thermodynamic quantities must satisfy,when phase transition of the charged black hole occurs.
Software requirements specification for the HAWK operating system
Holmes, V.P.; Harris, D.L.; Borgman, C.R.; Davidson, G.S.
1989-03-01
This document represents the original requirements specification for the HAWK operating system. HAWK is the operating system for the SANDAC V, a real-time embedded multiprocessor based on the Motorola 68020 microprocessor. When the effort to create the operating system was first undertaken, it was clear that a careful specification of the requirements would be vital. Unfortunately, there were few models to work from since requirement documents for operating systems of any kind are seldom published. The final form of the requirements used a functional organization adapted from the IEEE Guide to Software Requirements Specifications (ANSI/IEEE Std 830-1984). Hopefully, this document will provide a historical case study from which others can benefit when faced with similar circumstances. 2 refs., 4 figs.
Hawking Radiation of Linear Dilaton Black Holes in Various Theories
Pasaoglu, H
2009-01-01
Using the Damour-Ruffini-Sannan, the Parikh-Wilczek and the thin film brick-wall models, we investigate the Hawking radiation of uncharged massive particles from 4-dimensional linear dilaton black holes, which are the solutions to Einstein-Maxwell-Dilaton, Einstein-Yang-Mills-Dilaton and Einstein-Yang-Mills-Born-Infeld-Dilaton theories. Our results show that the tunneling rate is related to the change of Bekenstein-Hawking entropy. Contrary to the many studies in the literature, here the emission spectrum is precisely thermal. This implies that the derived emission spectrum is not consistent with the unitarity of the quantum theory, which would possibly lead to the information loss.
Hawking-Moss Tunneling in Noncommutative Eternal Inflation
Cai, Yi-Fu
2007-01-01
The quantum behavior of noncommutative eternal inflation is quite different from the usual knowledge. Unlike the usual eternal inflation, the quantum fluctuation of noncommutative eternal inflation is suppressed by the Hubble parameter. Due to this, we need to reconsider many conceptions of eternal inflation. In this paper we study the Hawking-Moss tunneling in noncommutative eternal inflation using the stochastic approach. We obtain a brand-new form of the tunneling probability for this process and find that the Hawking-Moss tunneling is more unlikely to take place in the noncommutative case than in the usual one. We also conclude that the lifetime of a metastable de-Sitter (dS) vacuum in the noncommutative spacetime is longer than that in the commutative case.
Toxicity of gentamicin in red-tailed hawks.
Bird, J E; Walser, M M; Duke, G E
1983-07-01
Gentamicin sulfate at dosage levels of 10 and 20 mg/kg of body weight was administered twice daily IV to red-tailed hawks. Clinical signs, water consumption, and changes in blood chemical values were monitored. Tissues were examined grossly and ultrastructurally, using light and electron microscopy. Clinical signs of weakness and apnea were attributed to gentamicin-induced neuromuscular blockade in the 20-mg/kg group. Serum values of aspartate transaminase, alanine transaminase, cholesterol, inorganic phosphorus, total protein, albumin, and uric acid increased in some birds. There was a decrease in periodic acid-Schiff staining of proximal tubular brush borders. Increased numbers of cytoplasmic lysosomes, many of which contained myelin figures, in renal epithelial cells were seen at the ultrastructural level. All birds given 20 mg/kg died. Both dosage levels were considered toxic in red-tailed hawks.
Hawking radiation as perceived by different observers (ERE2011 proceedings)
Barbado, Luis C; Garay, Luis J
2012-01-01
We study the perception of Hawking radiation by different observers outside a black hole. The analysis is done in terms of an effective-temperature function that varies along the trajectory of each observer. The vacuum state of the radiation field is chosen to be non-stationary, so as to mimic the switching-on of Hawking radiation that would appear in a real black hole collapse. We analyse how this vacuum is perceived by observers staying at a fixed radius, by observers coming in free-fall from radial infinity at different times, and by observers in free-fall released from finite radial positions. Results found have a compelling physical interpretation. One main result, at first unexpected, is that in general free-falling observers do perceive particle emission by the black hole when crossing the event horizon. This happens because of a diverging Doppler shift at the event horizon.
Black Hawk Down: Film Zwischen Reflektion und Konstruktion Gesellschaftlicher Wirklichkeit
Pötzsch, Holger
2009-05-01
BLACK HAWK DOWN: FILM BETWEEN THE REFLECTION AND CONSTRUCTION OF SOCIAL REALITY - In this article, Ridley Scott's film Black Hawk Down (USA 2001) is read in the context of contemporary theories concerning cultural memory (Jan and Aleida Assmann) and media culture (Douglas Kellner). It is argued that film (and representation in general) does not merely reflect a preceding reality; it also actively serves to construct it. It is shown how Scott's film privileges one particular perspective on an actual event and how this point of view is objectified and installed in the memory of Western media culture. What potential implications does an increased blurring of fact and fiction in the representation of war have? What are the consequences for political and pedagogical practice? What role can cultural studies play in these processes?
Kajian Kritis Terhadap Praanggapan Metafisis-Epistemologis Kosmologi Stephen Hawking
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.
Steven Hawking to visit Texas A&M in spring
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).
Trend detection in social networks using Hawkes processes
2015-01-01
International audience; —We develop in this paper a trend detection algorithm , designed to find trendy topics being disseminated in a social network. We assume that the broadcasts of messages in the social network is governed by a self-exciting point process, namely a Hawkes process, which takes into consideration the real broadcasting times of messages and the interaction between users and topics. We formally define trendiness and derive trend indices for each topic being disseminated in th...
Top scientists join Stephen Hawking at Perimeter Institute
Banks, Michael
2009-03-01
Nine leading researchers are to join Stephen Hawking as visiting fellows at the Perimeter Institute for Theoretical Physics in Ontario, Canada. The researchers, who include string theorists Leonard Susskind from Stanford University and Asoka Sen from the Harisch-Chandra Research Institute in India, will each spend a few months of the year at the institute as "distinguished research chairs". They will be joined by another 30 scientists to be announced at a later date.
Modulated Hawking radiation and a nonviolent channel for information release
Steven B. Giddings
2014-11-01
Full Text Available 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.
Critical reflexivity in financial markets: a Hawkes process analysis
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.
The Hawking cascade from a black hole is extremely sparse
Gray, Finnian; Van-Brunt, Alexander; Visser, Matt
2015-01-01
The Hawking flux from a black hole, (at least as seen from large distances), is extremely sparse and thin, with the average time between emission of successive Hawking quanta being hundreds of times larger than the natural timescale set by the energies of the emitted quanta. Some aspects of this result have been known for over 30 years, but have been largely forgotten, possibly because authors focussed mainly on the late-time high-temperature regime. We shall instead focus on the early-stage low-temperature regime, and shall both quantify and significantly extend these observations in a number of different ways. First we shall identify several natural dimensionless figures of merit, and thereby compare the mean time between emission of successive Hawking quanta to several quite natural timescales that can be associated with the emitted quanta, demonstrating that ratios of 300 or more are typical for emission of photons or gravitons from a Schwarzschild black hole. Furthermore these ratios are independent of t...
Scaling limits for Hawkes processes and application to financial statistics
Bacry, Emmanuel; Hoffmann, Marc; Muzy, Jean François
2012-01-01
We prove a law of large numbers and a functional central limit theorem for multivariate Hawkes processes observed over a time interval $[0,T]$ in the limit $T \\rightarrow \\infty$. We further exhibit the asymptotic behaviour of the covariation of the increments of the components of a multivariate Hawkes process, when the observations are imposed by a discrete scheme with mesh $\\Delta$ over $[0,T]$ up to some further time shift $\\tau$. The behaviour of this functional depends on the relative size of $\\Delta$ and $\\tau$ with respect to $T$ and enables to give a full account of the second-order structure. As an application, we develop our results in the context of financial statistics. We introduced in a previous work a microscopic stochastic model for the variations of a multivariate financial asset, based on Hawkes processes and that is confined to live on a tick grid. We derive and characterise the exact macroscopic diffusion limit of this model and show in particular its ability to reproduce important empiric...
Merriman, J.W.; Boal, C.W.; Bashore, T.L.; Zwank, P.J.; Wester, D.B.
2007-01-01
Some diurnal raptors are frequently observed at prairie dog (Cynomys sp.) colonies. As a result, some military installations have conducted prairie dog control activities to reduce the bird-aircraft strike hazard (BASH) potential of low-flying aircraft. To evaluate the validity of this management strategy, we assessed raptor associations with prairie dog colonies at 2 short-grass prairie study areas: southern Lubbock County, Texas, USA, and Melrose Bombing and Gunnery Range in east-central New Mexico, USA. We quantified diurnal raptors (i.e., Falconiformes) at plots occupied (colony plots) and unoccupied (noncolony plots) by black-tailed prairie dogs (Cynomys ludovicianus) at both sites throughout 2002. We compared the number of individual birds of a given species at colony and noncolony plots within each study area by season. Ferruginous hawks (Buteo regalis) and northern harriers (Circus cyaneus) were more abundant at colony plots, whereas Swainson's hawks (B. swainsoni) and American kestrels (Falco sparverius) were more abundant at noncolony plots. Red-tailed hawk (B. jamaicensis) abundance did not differ between the 2 plot types. Our results suggest prairie dog control as a method of reducing BASH potential may be effective at some sites but may be ineffective or even increase the BASH potential at others. Thus, bird-avoidance models assessing the BASH potential should be conducted on a site-specific basis using information on relative and seasonal abundances of individual raptor species and the relative strike risks they pose to aircraft.
Hawking Radiation of Scalar and Vector Particles From 5D Myers-Perry Black Holes
Jusufi, Kimet
2016-01-01
In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry (5D-MPBH) black hole with two independent angular momentum componentes. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlev\\'e coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equation by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.
Hawking Radiation of Scalar and Vector Particles from 5D Myers-Perry Black Holes
Jusufi, Kimet; Övgün, Ali
2017-06-01
In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry black hole (5D-MPBH) with two independent angular momentum components. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlevé coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equations by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.
Hawking Radiation of Scalar and Vector Particles from 5D Myers-Perry Black Holes
Jusufi, Kimet; Övgün, Ali
2017-02-01
In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry black hole (5D-MPBH) with two independent angular momentum components. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlevé coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equations by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.
Observation of quantum Hawking radiation and its entanglement in an analogue black hole
Steinhauer, Jeff
2016-10-01
We observe spontaneous Hawking radiation, stimulated by quantum vacuum fluctuations, emanating from an analogue black hole in an atomic Bose-Einstein condensate. Correlations are observed between the Hawking particles outside the black hole and the partner particles inside. These correlations indicate an approximately thermal distribution of Hawking radiation. We find that the high-energy pairs are entangled, while the low-energy pairs are not, within the reasonable assumption that excitations with different frequencies are not correlated. The entanglement verifies the quantum nature of the Hawking radiation. The results are consistent with a driven oscillation experiment and a numerical simulation.
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.)
Hawking Radiation via Damour-Ruffini Method in Squashed Charged Rotating Kaluza-Klein Black Holes
Hu, Ji-Wan; Wu, Jing-He; Liu, Xian-Ming
2017-02-01
Using the Damour-Ruffini method, Hawking radiation of charged particles from squashed charged rotating five-dimensional Kaluza-Klein black holes is investigated extensively. Under the generalized tortoise coordinate transformation, Hawking temperature of the black holes is calculated by using charged scalar particles and Dirac fermions respectively. We find that the obtained Hawking temperature for charged Dirac fermions is the same as for charged scalar particles. What's more, the spectrum of Hawking radiation contains the information of the size of the extra dimension, which could provide insight for further investigation of large extra dimensions in the future.
Information-carrying Hawking radiation and the number of microstate for a black hole
Cai, Qing-yu; You, Li
2016-01-01
We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein-Hawking entropies for Schwarzschild black holes and Reissner-Nordstr\\"om black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner-Nordstr\\"om black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein-Hawking entropy of extremal black holes in the semiclassical limit.
Hawking radiation of scalar particles from accelerating and rotating black holes
Gillani, Usman A.; Rehman, Mudassar; Saifullah, K., E-mail: mani_precious2001@yahoo.com, E-mail: mudassar051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-06-01
Hawking radiation of uncharged and charged scalar particles from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using this method we recover the correct Hawking temperature as well.
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 Kerr-Newman de Sitter black hole via anomalies
Lin Kai; Yang Shu-Zheng; Zeng Xiao-Xiong
2008-01-01
In this paper, Hawking radiation from the Kerr-Newman de Sitter black hole is studied via gauge anomaly and gravitational anomaly. The obtained results of Hawking radiation from the event horizon and the cosmological horizon accord with those by other methods.
Autumn raptor banding at hawk Ridge, Duluth, Minnesota USA, 1972-2009: An overview
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...
Horsfield's hawk-cuckoo nestlings simulate multiple gapes for begging.
Tanaka, Keita D; Ueda, Keisuke
2005-04-29
Nestlings of some brood parasitic birds evict hosts' eggs and young soon after hatching, thereby avoiding discrimination by hosts while monopolizing parental care. Eviction carries a cost, however, because lone parasitic nestlings attract a reduced provisioning rate. Here we describe a form of visual signaling used by the evicting Horsfield's hawk-cuckoo (Cuculus fugax) to obtain sufficient food. The chick displays a gape-colored patch on the wing to the host parents as they deliver food, simulating the gaping display of more than one nestling.
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Crepin, Kofane Timoleon
2016-01-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.
Lorentz Invariance Violation and Modified Hawking Fermions Tunneling Radiation
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.
Perspectiva narrativa sobre HISTORIA DEL TIEMPO, de Stephen Hawking
García Landa, José Angel
2011-01-01
Reseña con resumen y comentario de HISTORIA DEL TIEMPO, de Stephen Hawking, sintetizando las tesis principales del libro y evaluándolas desde el punto de vista de una filosofía del tiempo (tanto cósmico como humano) informada por la teoría narrativa y la filosofía evolucionista. Cualquier historia o teoría del tiempo, por compleja que sea, ha de volverse más complicada una vez se tiene en cuenta el papel de las descripciones, modelos y teorías en tanto que instrumentos cognitivos históricamen...
Kolmogorov-Sinai and Bekenstein-Hawking entropies
Ropotenko, K
2007-01-01
It is shown that instability of stringy matter near the event horizon of a black hole (the spreading effect) can be characterized by the Lyapunov exponents. For a homogeneous and isotropic horizon the (average) Lyapunov exponent coincides with the Kolmogorov-Sinai entropy of stringy matter. Due to identity of phase space volume of the string with the area of the horizon the relation between the Kolmogorov-Sinai and Bekenstein-Hawking entropies is established. The Kolmogorov-Sinai entropy measures the rate at which information about the string state is lost as the string spreads over the horizon.
Bekenstein-Hawking Entropy as Topological Entanglement Entropy
McGough, Lauren; Verlinde, Herman
2013-01-01
Black holes in 2+1 dimensions enjoy long range topological interactions similar to those of non-abelian anyon excitations in a topologically ordered medium. Using this observation, we compute the topological entanglement entropy of BTZ black holes, via the established formula S_top = log(S^a_0), with S_b^a the modular S-matrix of the Virasoro characters chi_a(tau). We find a precise match with the Bekenstein-Hawking entropy. This result adds a new twist to the relationship between quantum ent...
TC81220F (HAWK) MPEG 2 system decoder LSI; MPEG2 system decoder LSI TC81220F (HAWK)
NONE
1999-03-01
Satellite broadcasting, cable broadcasting, and ground wave broadcasting have been digitized gradually. In the video and audio data communication, the MPEG2 (Moving Picture Experts Group 2) technology for compression and extension is important. A system LSI that includes an MPEG2 decoder in a receiving set (Set Top Box) is required to each broadcasting. To deduce the system cost, Toshiba developed a TX3904 MCU (microcontroller) that controls the system, a transport processor that selects the packet-multiplexed data, and TC81220F (HAWK) that puts MPEG2 audio video decoders in one chip. (translated by NEDO)
Hawking radiation and classical tunneling: A ray phase space approach
Tracy, E. R.; Zhigunov, D.
2016-01-01
Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by Unruh and others as a conceptual model for "Hawking radiation." Here, we use variational methods, originally introduced by Brizard for the study of linearized MHD, and ray phase space methods, to analyze linearized acoustics in the presence of background flows. The variational formulation endows the evolution equations with natural Hermitian and symplectic structures that prove useful for later analysis. We derive a 2 × 2 normal form governing the wave evolution in the vicinity of the "event horizon." This shows that the acoustic model can be reduced locally (in ray phase space) to a standard (scalar) tunneling process weakly coupled to a unidirectional non-dispersive wave (the "incoming wave"). Given the normal form, the Hawking "thermal spectrum" can be derived by invoking standard tunneling theory, but only by ignoring the coupling to the incoming wave. Deriving the normal form requires a novel extension of the modular ray-based theory used previously to study tunneling and mode conversion in plasmas. We also discuss how ray phase space methods can be used to change representation, which brings the problem into a form where the wave functions are less singular than in the usual formulation, a fact that might prove useful in numerical studies.
Tunneling method for Hawking radiation in the Nariai case
Belgiorno, F.; Cacciatori, S. L.; Dalla Piazza, F.
2017-08-01
We revisit the tunneling picture for the Hawking effect in light of the charged Nariai manifold, because this general relativistic solution, which displays two horizons, provides the bonus to allow the knowledge of exact solutions of the field equations. We first perform a revisitation of the tunneling ansatz in the framework of particle creation in external fields à la Nikishov, which corroborates the interpretation of the semiclassical emission rate Γ_{emission} as the conditional probability rate for the creation of a couple of particles from the vacuum. Then, particle creation associated with the Hawking effect on the Nariai manifold is calculated in two ways. On the one hand, we apply the Hamilton-Jacobi formalism for tunneling, in the case of a charged scalar field on the given background. On the other hand, the knowledge of the exact solutions for the Klein-Gordon equations on Nariai manifold, and their analytic properties on the extended manifold, allow us a direct computation of the flux of particles leaving the horizon, and, as a consequence, we obtain a further corroboration of the semiclassical tunneling picture from the side of S-matrix formalism.
Comparative morphology among northern populations of breeding Cooper's Hawks
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.
Modified Bekenstein-Hawking System in f( R) Gravity
Dutta, Jibitesh; Mitra, Saugata; Chetry, Binod
2016-10-01
The present work deals with four alternative formulation of Bekenstein system on event horizon in f( R) gravity. While thermodynamical laws holds in universe bounded by apparent horizon, these laws break down on event horizon. With alternative formulation of thermodynamical parameters (temperature and entropy), thermodynamical laws hold on event horizon in Einstein Gravity. With this motivation, we extend the idea of generalised Hawking temperature and modified Bekenstein entropy in homogeneous and isotropic model of universe on event horizon and examine whether thermodynamical laws hold in f(R) gravity. Specifically, we examine and compare validity of generalised second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) in four alternative modified Bekenstein scenarios. As Dark energy is a possible dominant candidate for matter in the univerese and Holographic Dark Energy (HDE) can give effective description of f(R) gravity, so matter in the universe is taken as in the form interacting HDE. In order to understand the complicated expressions, finally the above laws are examined from graphical representation using three Planck data sets and it is found that generalised/modified Hawking temperature has a crucial role in making perfect thermodynamical system.
Davud Kuhi
2015-11-01
Full Text Available Thanks to the development of the concept of metadiscourse, it is now widely acknowledged that academic/scientific writing is not only concerned with communicating purely propositional meanings: what is communicated through academic/scientific communication is seen to be intertwined with the negotiation of social and interpersonal meanings. While a large number of so called metadiscoursal resources contribute to the simultaneous negotiation of propositional and interpersonal meanings, the present study aimed at investigating the functions self-mention forms can fulfill in academic/scientific communication. Two of Stephen Hawking's scientific books were selected as the corpus of the research, and based on Tang and John's (1999 model, the constructed corpus was analyzed in terms of the functions self-mention forms can fulfill in academic/scientific writing. The findings revealed that from among the different roles identified by Tang and John, the representative role constituted the most frequent self-mention function in the corpus. The remarkably heavy presence of representative role in Hawking's scientific prose was interpreted as a further evidence for the claim that scientists are more likely to persuade readers of their ideas if they frame their messages in ways which appeal to appropriate community-recognized relationships.
Hawking fluxes and anomalies in rotating regular black holes with a time-delay
Takeuchi, Shingo
2016-11-01
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.
Backreaction of Hawking radiation on a gravitationally collapsing star I: Black holes?
Laura Mersini-Houghton
2014-11-01
Full Text Available Particle creation leading to Hawking radiation is produced by the changing gravitational field of the collapsing star. The two main initial conditions in the far past placed on the quantum field from which particles arise, are the Hartle–Hawking vacuum and the Unruh vacuum. The former leads to a time-symmetric thermal bath of radiation, while the latter to a flux of radiation coming out of the collapsing star. The energy of Hawking radiation in the interior of the collapsing star is negative and equal in magnitude to its value at future infinity. This work investigates the backreaction of Hawking radiation on the interior of a gravitationally collapsing star, in a Hartle–Hawking initial vacuum. It shows that due to the negative energy Hawking radiation in the interior, the collapse of the star stops at a finite radius, before the singularity and the event horizon of a black hole have a chance to form. That is, the star bounces instead of collapsing to a black hole. A trapped surface near the last stage of the star's collapse to its minimum size may still exist temporarily. Its formation depends on the details of collapse. Results for the case of Hawking flux of radiation with the Unruh initial state, will be given in a companion paper II.
Covariant anomalies and Hawking radiation from Kaluza–Klein AdS black holes
Chuan-Yi Bai
2013-02-01
In this paper, Hawking radiation is studied from four-dimensional (4D) Kaluza–Klein (KK) AdS black holes via the method of anomaly cancellation. The {|bf KK-AdS} black hole considered is a non-extremal charged rotating solution in the theory of 4D gauged supergravity. Its Hawking fluxes of electric charge, angular momentum and energy momentum tensor are derived here. Our results support the common view that Hawking radiation is the quantum effect arising at the event horizon.
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
Rahman, M. Atiqur, E-mail: atirubd@yahoo.com [Department of Applied Mathematics, Rajshahi University (Bangladesh); Hossain, M. Ilias, E-mail: ilias_math@yahoo.com [Department of Mathematics, Rajshahi University, Rajshahi, 6205 (Bangladesh)
2012-05-30
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.
Hawking radiation of Kerr-de Sitter black holes using Hamilton-Jacobi method
Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.
2013-05-01
Hawking radiation of Kerr-de Sitter black hole is investigated using Hamilton-Jacobi method. When the well-behaved Painleve coordinate system and Eddington coordinate are used, we get the correct result of Bekenstein-Hawking entropy before and after radiation but a direct computation will lead to a wrong result via Hamilton-Jacobi method. Our results show that the tunneling probability is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal but it is consistent with underlying unitary theory.
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
Rahman, M. Atiqur; Hossain, M. Ilias
2012-05-01
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.
Hawking Radiation of Schwarzschild-de Sitter Black Hole by Hamilton-Jacobi method
Rahman, M Atiqur; 10.1016/j.physletb.2012.04.049
2012-01-01
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek\\rq s opinion and gives a correction to the Hawking radiation of SdS black hole.
Raptor community composition in the Texas Southern High Plains lesser prairie-chicken range
Behney, A.C.; Boal, Clint W.; Whitlaw, H.A.; Lucia, D.R.
2012-01-01
Predation can be a factor in preventing prey population growth and sustainability when prey populations are small and fragmented, and when predator density is unrelated to the density of the single prey species. We conducted monthly raptor surveys from February 2007 to May 2009 in adjacent areas of the Texas Southern High Plains (USA) that do and do not support lesser prairie-chickens (Tympanuchus pallidicinctus), a candidate for protection under the Endangered Species Act. During the summer period corresponding to prairie-chicken nesting and brood-rearing, Swainson's hawks (Buteo swainsoni) were the most abundant raptor. During the lekking and overwintering period, the raptor community was diverse, with northern harriers (Circus cyaneus) being the most abundant species. Raptor abundance peaked during the early autumn and was lowest during the spring. Utility poles were a significant predictor of raptor density at survey points and Swainson's hawks and all raptors, pooled, were found in greater densities in non-prairie-chicken habitat dominated by mesquite (Prosopis glandulosa). Avian predation risk on prairie-chickens, based on presence and abundance of raptors, appears to be greatest during winter when there is a more abundant and diverse raptor community, and in areas with utility poles.
The imprint of the Hawking effect in subcritical flows
Coutant, Antonin
2016-01-01
We study the propagation of low frequency shallow water waves on a one dimensional flow of varying depth. When taking into account dispersive effects, the linear propagation of long wavelength modes on uneven bottoms excites new solutions of the dispersion relation which possess a much shorter wavelength. The peculiarity is that one of these new solutions has a negative energy. When the flow becomes supercritical, this mode has been shown to be responsible for the (classical) analog of the Hawking effect. For subcritical flows, the production of this mode has been observed numerically and experimentally, but the precise physics governing the scattering remained unclear. In this work, we provide an analytic treatment of this effect in subcritical flows. We analyze the scattering of low frequency waves using a new perturbative series, derived from a generalization of the Bremmer series. We show that the production of short wavelength modes is governed by a complex value of the position: a complex turning point....
Tunneling method for Hawking radiation in the Nariai case
Belgiorno, F; Piazza, F Dalla
2016-01-01
Particle creation associated with the Hawking effect is calculated in the case of the charged Nariai solution, for the case both of the event horizon and of the cosmological horizon. We apply the Hamilton-Jacobi formalism, and, after a revisitation in the framework of particle creation in external fields {\\sl \\`a la} Nikishov, we consider in particular the case of a charged scalar field on the given background. Due to the knowledge of the exact solutions for the Klein-Gordon equations on Nariai manifold, and to their analytic properties on the extended manifold, we can corroborate the tunneling picture also by means of a direct computation of the flux of particles leaving the horizon.
A silence black hole: Hawking radiation at the Hagedorn temperature
Lorente-Espin, O
2008-01-01
We compute semi-classically the Hawking emission for different types of black hole in type II string theory. In particular we analyze the thermal transition between NS5 branes and Little String Theory, finding compelling evidence for information recovering. We find that once the near horizon limit is taken the emission of a full family of models is exactly thermal even if back-reaction is taken into account. Consequently these theories are non-unitary and can not convey any information about the black hole internal states. It is argue that this behaviour matches the string theory expectations. We suggest a plausible reason for the vanishing of the jet-quenching parameter in such theories.
Hawking Radiation from the Horowitz-Strominger Black Hole
FANG Heng-Zhong; HU Ya-Peng; ZHAO Zheng
2005-01-01
@@ When a black hole radiates particles, it losses energy and shrinks, the horizon contracts from its original radius to a new smaller radius. This leads to the separation between the initial and finalradii, which sets the barrier for the particles to tunnel. We develop the work of Parikh [Phys. Rev. Lett. 85 (2000) 5042; Gen. Rel. Gray.36 (2004) 2419] to a Horowitz-Strominger black hole, i.e. applying the Wentzel-Kramers-Brillouin approximation and semi-classical method to calculate the rate of the Hawking radiation. The result agrees with Γ～ e-2ImI =e△SBH. It is also proven that the energy spectrum deviates from exact thermality.
The Hawking effect in dielectric media and the Hopfield model
Belgiorno, F; Piazza, F Dalla
2014-01-01
We consider the so-called Hopfield model for the electromagnetic field in a dielectric dispersive medium in a framework in which one allows a space-time dependence of microscopic parameters, aimed to a phenomenological description of a space-time varying dielectric perturbation induced by means of the Kerr effect. We discuss the analogue Hawking effect, by first analyzing the geometrical optics for the Hopfield model, and then by introducing a simplified model which has the bonus to avoid many difficulties which are involved in the full Hopfield model, still keeping the same dispersion relation. Amplitude calculations are indicated, and generalized Manley-Rowe identities are derived in a quantum scattering theory framework. Our main result is an analytical calculation of the spontaneous thermal emission in the single-branch case, which is provided non perturbatively for the first time in the framework of dielectric black holes. An universal mechanism for thermality between optical black holes and acoustic bla...
Dark Spinors Hawking Radiation in String Theory Black Holes
R. T. Cavalcanti
2016-01-01
Full Text Available The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
Is the Hawking Quasilocal Energy “Newtonian”?
Valerio Faraoni
2015-11-01
Full Text Available The Misner–Sharp–Hernandez mass defined in general relativity and in spherical symmetry has been recognized as having a Newtonian character in previous literature. In order to better understand this feature we relax spherical symmetry and we study the generalization of the Misner–Sharp–Hernandez mass to general spacetimes, i.e., the Hawking quasilocal mass. The latter is decomposed into a matter contribution and a contribution coming solely from the Weyl tensor. The Weyl tensor is then decomposed into an electric part (which has a Newtonian counterpart and a magnetic one (which does not, which further splits the quasilocal mass into “Newtonian” and “non-Newtonian” parts. Only the electric (Newtonian part contributes to the quasilocal mass.
Modified Bekenstein-Hawking system in $f(R)$ gravity
Dutta, Jibitesh; Chetry, Binod
2016-01-01
The present work deals with four alternative formulation of Bekenstein system on event horizon in $f(R)$ gravity. While thermodynamical laws holds in universe bounded by apparent horizon, these laws break down on event horizon. With alternative formulation of thermodynamical parameters (temperature and entropy), thermodynamical laws hold on event horizon in Einstein Gravity. With this motivation, we extend the idea of generalised Hawking temperature and modified Bekenstein entropy in homogeneous and isotropic model of universe on event horizon and examine whether thermodynamical laws hold in f(R) gravity. Specifically, we examine and compare validity of generalised second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) in four alternative modified Bekenstein scenarios. As Dark energy is a possible dominant candidate for matter in the univerese and Holographic Dark Energy (HDE) can give effective description of f(R) gravity, so matter in the universe is taken as in the form interacting HDE. I...
Comprehensive study of endurance for IAR-99 Hawk
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.
Extraction, purification and characterization of polysaccharides from Hawk tea.
Jia, Xuejing; Ding, Chunbang; Yuan, Shu; Zhang, Zhongwei; Chen, Yang'er; Du, Lei; Yuan, Ming
2014-01-01
In the present study, the extraction, purification and characterization of polysaccharides from Hawk mature leaf tea (HMP) were investigated. The optimal extraction parameters were obtained by using a Box-Behnken design as follows: extraction temperature 88.9 °C, extraction time 128.2 min and ratio of water to solid 11.4 mL/g. The crude HMP was sequentially purified by chromatography of DEAE-52, and two purified fractions, HMP-1 and HMP-2, were obtained. HMP-1 and HMP-2 were mainly composed of arabinose, galactose, glucose and mannose with the molecular weight of 133 and 100 kDa, respectively. For antioxidant activities in vitro, HMP-1 had strong 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing activity power (FRAP). These results provide a scientific basis for the further use of polysaccharides from this traditional herb tea. Copyright © 2013 Elsevier Ltd. All rights reserved.
Towards a Hartle-Hawking state for loop quantum gravity
Dhandhukiya, Satya
2016-01-01
The Hartle-Hawking state is a proposal for a preferred initial state for quantum gravity, based on a path integral over all compact Euclidean four-geometries which have a given three-geometry as a boundary. The wave function constructed this way satisfies the (Lorentzian) Hamiltonian constraint of general relativity in ADM variables in a formal sense. In this article we mimic this procedure of constructing an initial state in terms of Ashtekar-Barbero variables, and observe that the wave function thus constructed does not satisfy the Lorentzian Hamiltonian constraint even in a formal sense. We also investigate this issue for the relativistic particle. We finally suggest a modification of the proposal that does satisfy the constraint at least in a formal sense and start to consider its implications in quantum cosmology.
Correlations in Hawking radiation and the infall problem
Mathur, Samir D
2011-01-01
It is sometimes believed that small quantum gravity effects can encode information as `delicate correlations' in Hawking radiation, thus saving unitarity while maintaining a semiclassical horizon. A recently derived inequality showed that this belief is incorrect: one must have order unity corrections to low energy evolution at the horizon (i.e. fuzzballs) to remove entanglement between radiation and the hole. In this paper we take several models of `small corrections' and compute the entanglement entropy numerically; in each case this entanglement is seen to monotonically grow, in agreement with the general inequality. We also construct a model of `burning paper', where the entanglement is found to rise and then return to zero, in agreement with the general arguments of Page. We then note that the fuzzball structure of string microstates offers a version of `complementarity'. Low energy evolution is modified by order unity, resolving the information problem, while for high energy infalling modes ($E>> kT$) w...
Hawking Radiation and Nonequilibrium Quantum Critical Current Noise
Sonner, Julian; Green, A. G.
2012-08-01
The dynamical scaling of quantum critical systems in thermal equilibrium may be inherited in the driven steady state, leading to universal out-of-equilibrium behavior. This attractive notion has been demonstrated in just a few cases. We demonstrate how holography—a mapping between the quantum critical system and a gravity dual—provides an illuminating perspective and new results. Nontrivial out-of-equilibrium universality is particularly apparent in current noise, which is dual to Hawking radiation in the gravitational system. We calculate this in a two-dimensional system driven by a strong in-plane electric field and deduce a universal scaling function interpolating between previously established equilibrium and far-from-equilibrium current noise. Since this applies at all fields, out-of-equilibrium experiments no longer require very high fields for comparison with theory.
High prevalence of Sarcocystis calchasi sporocysts in European Accipiter hawks.
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.
Christopher Hawkes and the International Summer Courses of Ampurias
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.
Higgs v Hawking: a battle of the heavyweights that has shaken the world of theoretical physics
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).
Information-carrying Hawking radiation and the number of microstate for a black hole
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.
Non-Riemannian effective spacetime effects on Hawking radiation in superfluids
Garcia de Andrade, L C
2005-01-01
Riemannian effective spacetime description of Hawking radiation in $^{3}He-A$ superfluids is extended to non-Riemannian effective spacetime. An example is given of non-Riemannian effective geometry of the rotational motion of the superfluid vacuum around the vortex where the effective spacetime Cartan torsion can be associated to the Hawking giving rise to a physical interpretation of effective torsion recently introduced in the literature in the form of an acoustic torsion in superfluid $^{4}He$ (PRD-70(2004),064004). Curvature and torsion singularities of this $^{3}He-A$ fermionic superfluid are investigated. This Lense-Thirring effective metric, representing the superfluid vacuum in rotational motion, is shown not support Hawking radiation when the isotropic $^{4}He$ is restored at far distances from the vortex axis. Hawking radiation can be expressed also in topological solitons (moving domain walls) in fermionic superfluids in non-Riemannian (teleparallel) $(1+1)$ dimensional effective spacetime. A telep...
Information-carrying Hawking radiation and the number of microstate for a black hole
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.
The GUP effect on Hawking radiation of the 2 + 1 dimensional black hole
Gecim, Ganim; Sucu, Yusuf
2017-10-01
We investigate the Generalized Uncertainty Principle (GUP) effect on the Hawking radiation of the 2 + 1 dimensional Martinez-Zanelli black hole by using the Hamilton-Jacobi method. In this connection, we discuss the tunneling probabilities and Hawking temperature of the spin-1/2 and spin-0 particles for the black hole. Therefore, we use the modified Klein-Gordon and Dirac equations based on the GUP. Then, we observe that the Hawking temperature of the scalar and Dirac particles depend on not only the black hole properties, but also the properties of the tunneling particle, such as angular momentum, energy and mass. And, in this situation, we see that the tunneling probability and the Hawking radiation of the Dirac particle is different from that of the scalar particle.
No Information Is Lost: a Revisit of Hawking Radiation as Tunneling
Zhang, Baocheng; Zhan, Ming-sheng; You, Li
2009-01-01
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-Nordstr\\"{o}m black hole, the Kerr black hole, and the Kerr-Newman black hole. The special cases of tunneling through a quantum horizon and geometrically non-commutative black holes are 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, must be a unitary process.
Bureau of Land Management, Department of the Interior — This map shows the potential current distribution of Ferruginous Hawk, in the context of current and near-term terrestrial intactness and long-term potential for...
Proposal for Red-shouldered Hawk inventory and monitoring Mississippi River- Year 2000
US Fish and Wildlife Service, Department of the Interior — This is a proposal to conduct Red-shouldered Hawk inventory and monitoring research along the Mississippi River. Objectives of the proposed study include: (1)...
Hawking radiation of Reissner-Nordstrom-de Sitter black hole by Hamilton-Jacobi method
Hossain, M Ilias
2013-01-01
In Refs. (M. Atiqur Rahman, M. Ilias Hossain (2012) Phys. Lett. B {\\bf 712} 1), we have developed Hamilton-Jacobi method for dynamical spacetime and discussed Hawking radiation of Schwarzschild-de Sitter black hole by massive particle tunneling method. In this letter, we have investigated the hawking purely thermal and nonthermal radiations of Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole. We have considered energy and angular momentum as conserved and shown that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results we have obtained for RNdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and recovered the new result for Hawking radiation of RNdS black hole.
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.
Spherically Symmetric Static Solution for a Schwarzschild Black Hole with Its Hawking Radiation
HUANG Chao-Guang
2000-01-01
A black hole and its Hawking radiation may be in stable thermal equilibrium. In this letter, the static spherically symmetric numerical solution for a Schwarzschild black hole with its Hawking radiation are obtained. In the calculation, the equilibrium system is supposed to consist of a black hole, thermal radiation and a two-dimensional surface layer. The solutions obtained are compared with the York's back-reaction approach and the Zhao-Liu thermodynamic approach.
Hawking temperature of Kerr-Newman-AdS black hole from tunneling
Ma, Zheng Ze
2009-01-01
Using the null-geodesic tunneling method of Parikh and Wilczek, we derive the Hawking temperature of a general four-dimensional rotating black hole. In order to eliminate the motion of $\\phi$ degree of freedom of a tunneling particle, we have chosen a reference system that is co-rotating with the black hole horizon. Then we give the explicit result for the Hawking temperature of the Kerr-Newman-AdS black hole from the tunneling approach.
Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly
Peng Jun-Jin; Wu Shuang-Qing
2008-01-01
This paper derives the Hawking flux from the Schwarzschild black hole with a global monopole by using Robinson and Wilczek's method.Adopting a dimensional reduction technique, it can describe the effective quantum field in the (3+1)-dimensional global monopole background by an infinite collection of the (1+1)-dimensional maesless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)-dimensional black body radiation at the Hawking temperature.
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
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.
Black hole and hawking radiation by type-II Weyl fermions
Volovik, G. E.
2016-11-01
The type-II Weyl and type-II Dirac fermions may emerge behind the event horizon of black holes. Correspondingly, the black hole can be simulated by creation of the region with overtilted Weyl or Dirac cones. The filling of the electronic states inside the "black hole" is accompanied by Hawking radiation. The Hawking temperature in the Weyl semimetals can reach the room temperature, if the black hole region is sufficiently small, and thus the effective gravity at the horizon is large.
Hawking radiation from the dilaton-(anti) de Sitter black hole via covariant anomaly
Han Yi-Wen; Bao Zhi-Qing; Hong Yun
2009-01-01
Adopting the anomaly cancellation method, initiated by Robinson and Wilczek recently, this paper discusses Hawking radiation from the dilaton-(anti) de Sitter black hole. To save the underlying gauge and general covariance, it introduces covariant fluxes of gauge and energy-momentum tensor to cancel the gauge and gravitational anomalies. The result shows that the introduced compensating fluxes are equivalent to those of a 2-dimensional blackbody radiation at Hawking temperature with appropriate chemical potential.
Hawking effect of Dirac particles in non-stationary Kerr space-time
黎忠恒; 赵峥
1995-01-01
In the process of dealing with the Hawking effect of Dirac particles in the non-stationary Kerr space-time, a new universal method to define the generalized Tortoise coordinate transformation is given. By means of this coordinate transformation, one can discuss the properties of the dynamical equation of particles near event horizons, and get automatically the temperature of Hawking radiation using the method suggested by Damour and others, and thereby dodge the difficulties in calculating the renormalised energy-momentum tensor.
Hawking Radiation of Spin-1 Particles From Three Dimensional Rotating Hairy Black Hole
Sakalli, I
2015-01-01
In the present article, we study the Hawking radiation (HR) of spin-1 particles -- so-called vector particles -- from a three dimensional (3D) rotating black hole with scalar hair (RBHWSH) using Hamilton-Jacobi (HJ) ansatz. Putting the Proca equation amalgamated with the WKB approximation in process, the tunneling spectrum of vector particles is obtained. We recover the standard Hawking temperature corresponding to the emission of these particles from RBHWSH.
Hawking Radiation of Vector Particles via Tunneling From 4-Dimensional And 5-Dimensional Black Holes
Feng, Zhongwen; Zu, Xiaotao
2016-01-01
Using Proca equation and WKB approximation, we investigate Hawking radiation of vector particles via tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole. The results show that the tunneling rates and Hawking temperatures are depended on the properties of spacetime (event horizon, mass and angular momentum). Besides, our results are the same as scalars and fermions tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole.
Black hole and Hawking radiation by type-II Weyl fermions
Volovik, G E
2016-01-01
The type-II Weyl and type-II Dirac fermions may emerge behind the event horizon of black holes. Correspondingly the black hole can be simulated by creation of the region with overtilted Weyl or Dirac cones. The filling of the electronic states inside the "black hole" is accompanied by Hawking radiation. The Hawking temperature in the Weyl semimetals can reach the room temperature, if the black hole region is sufficiently small, and thus the effective gravity at the horizon is large.
The Trilinear Hamiltonian: A Zero Dimensional Model of Hawking Radiation from a Quantized Source
Nation, P. D.; Blencowe, M. 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. The conditions are derived 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 radi...
Analogue Hawking Radiation in a dc-SQUID Array Transmission Line
Nation, P. D.; Blencowe, M. P.; Rimberg, A. J.; Buks, E.
2009-08-01
We propose the use of a superconducting transmission line formed from an array of direct-current superconducting quantum interference devices for investigating analogue Hawking radiation. Biasing the array with a space-time varying flux modifies the propagation velocity of the transmission line, leading to an effective metric with a horizon. Being a fundamentally quantum mechanical device, this setup allows for investigations of quantum effects such as backreaction and analogue space-time fluctuations on the Hawking process.
Stephen Hawking, the Grand Design and the mass media communication: Philosophy, Science and Religion
Leandro Sequeiros
2014-11-01
Full Text Available The return of summer vacances 2010 coincide with the notice concerning the inminent publication of a provocative and scandalous book by the eminent Phisicist Stephen Hawking. The Grand Design came out on September 7 in EE.UU. and on 9 in United Kingdom. On November 15th, the Spanish edition have been issued. The Spanish newpapers have published some fragments, which apparently show Hawking intends to prove scientifically that God not exists. The communications media remark by different ways the scarce frangments of the text: «God is not necessary», «Hawking proves God not exists», «Creator God is a destroyed mith», «Hawking scientifically proves God not exists», «God expeled of the Universe»… We have tracked more than hundred web-pages in which the contents of Hawking book are comment. Rationalists and religious sectors have standed in the debate. But, what has Hawking really defended in The Grand Design?
Bee-hawking by the wasp, Vespa velutina, on the honeybees Apis cerana and A. mellifera.
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.
Bee-hawking by the wasp, Vespa velutina, on the honeybees Apis cerana and A. mellifera
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.
Theories of Everything and Hawking's Wave Function of the Universe
Hartle, J B
2002-01-01
If a cat, a cannonball, and an economics textbook are all dropped from the same height, they fall to the ground with exactly the same acceleration under the influence of gravity. This equality of gravitational accelerations of different things is one of the most accurately tested laws of physics. That law, however, tells us little about cats, cannonballs, or economics. This lecture expands on this theme to address the question of what features of our world are predicted by a fundamental ``theory of everything'' governing the regularities exhibited universally by all physical systems. This may consist of two parts: a dynamical law governing regularities in time (e.g superstring theory) and a law of cosmological initial condition governing mostly regularities in space (e.g. Hawking's no-boundary initial condition). The lecture concludes that: (1) ``A theory of everything'' is not a theory of everything in a quantum mechanical universe. (2) If the laws are short enough to be discoverable then they are probably t...
Hawking radiation with dispersion versus breakdown of WKB
Schützhold, R
2013-01-01
Inspired by the condensed matter analogues of black holes (a.k.a. dumb holes), we study Hawking radiation in the presence of a modified dispersion relation which becomes super-luminal at large wave-numbers. In the usual stationary coordinates $(t,x)$, one can describe the asymptotic evolution of the wave-packets in WKB, but this WKB approximation breaks down in the vicinity of the horizon, thereby allowing for a mixing between initial and final creation and annihilation operators. Thus, one might be tempted to identify this point where WKB breaks down with the moment of particle creation. However, using different coordinates $(\\tau,U)$, we find that one can evolve the waves so that WKB in these coordinates is valid throughout this transition region -- which contradicts the above identification of the breakdown of WKB as the cause of the radiation. Instead, our analysis suggests that the tearing apart of the waves into two different asymptotic regions (inside and outside the horizon) is the major ingredient of...
Search for QCD Hawking Radiation in Heavy Ion Collisions
Stiles, Laura; Murray, Michael
2008-04-01
A wide variety of measurements at RHIC, for example v2 and energy loss, suggest that the partonic matter created in heavy collisions thermalizes early. One possible mechanism for this is the creation of the QCD analogue to gravitational black holes [1]. Such objects have no memory of their creation and radiate with a characteristic temperature, T, that can depend only on their energy, charge, and angular momentum. This hypothesis is consistent with the growth of multiplicity with s in e+e- collisions and thermal temperature observed at LEP. For central heavy ion collisions the angular momentum of the system is approximately zero and the model predicts a universal dependence of the chemical freezeout temperature on the ratios of charge to transverse energy. To test this prediction against BRAHMS data, We have fitted data on π, K, p and p from central Au + Au collisions at several rapidities and energies, using the THERMUS code. The experimental dependence of the temperature on the ratio of charge to transverse energy will be compared to the Hawking radiation predictions. By comparing data sets at different energy, centrality and rapidity we can select systems with the same ratio of baryon number to energy but different rapidities. This may allow us to test for any effect of angular momentum on temperature. [1] P. Castorina, D. Kharzeev and H. Satz, Eur. Phys. J. C 52, 187 (2007)
The Hawking temperature in the context of dark energy
Gangopadhyay, Debashis; Manna, Goutam
2012-11-01
An emergent-gravity metric incorporating k-essence scalar fields ϕ having a Born-Infeld-type Lagrangian is mapped into a metric whose structure is similar to that of a blackhole of large mass M that has swallowed a global monopole. However, here the field is not that of a monopole but rather that of a k-essence scalar field. If ϕemergent are the solutions of the emergent-gravity equations of motion under cosmological boundary conditions at ∞, then for r\\rightarrow \\infty the rescaled field \\frac {\\phi _{emergent}}{2GM-1} has exact correspondence with ϕ with ϕ(r,t) = ϕ1(r) + ϕ2(t). The Hawking temperature of this metric is T_{ emergent}= \\frac {\\hbar c^{3}}{8\\pi GM k_{B}}(1-K)^{2}\\equiv \\frac {\\hbar }{8\\pi GM k_{B}}(1-K)^{2} , taking the speed of light c = 1. Here K=\\dot \\phi _{2}^{2} is the kinetic energy of the k-essence field ϕ and K is always less than unity, kB is the Boltzmann constant. This is phenomenologically interesting in the context of Belgiorno et al.'s gravitational analogue experiment.
The three-body problem from Pythagoras to Hawking
Valtonen, Mauri; Kholshevnikov, Konstantin; Mylläri, Aleksandr; Orlov, Victor; Tanikawa, Kiyotaka
2016-01-01
This book, written for a general readership, reviews and explains the three-body problem in historical context reaching to latest developments in computational physics and gravitation theory. The three-body problem is one of the oldest problems in science and it is most relevant even in today’s physics and astronomy. The long history of the problem from Pythagoras to Hawking parallels the evolution of ideas about our physical universe, with a particular emphasis on understanding gravity and how it operates between astronomical bodies. The oldest astronomical three-body problem is the question how and when the moon and the sun line up with the earth to produce eclipses. Once the universal gravitation was discovered by Newton, it became immediately a problem to understand why these three-bodies form a stable system, in spite of the pull exerted from one to the other. In fact, it was a big question whether this system is stable at all in the long run. Leading mathematicians attacked this problem over more than...
Permeable Surface Corrections for Ffowcs Williams and Hawkings Integrals
Lockard, David P.; Casper, Jay H.
2005-01-01
The acoustic prediction methodology discussed herein applies an acoustic analogy to calculate the sound generated by sources in an aerodynamic simulation. Sound is propagated from the computed flow field by integrating the Ffowcs Williams and Hawkings equation on a suitable control surface. Previous research suggests that, for some applications, the integration surface must be placed away from the solid surface to incorporate source contributions from within the flow volume. As such, the fluid mechanisms in the input flow field that contribute to the far-field noise are accounted for by their mathematical projection as a distribution of source terms on a permeable surface. The passage of nonacoustic disturbances through such an integration surface can result in significant error in an acoustic calculation. A correction for the error is derived in the frequency domain using a frozen gust assumption. The correction is found to work reasonably well in several test cases where the error is a small fraction of the actual radiated noise. However, satisfactory agreement has not been obtained between noise predictions using the solution from a three-dimensional, detached-eddy simulation of flow over a cylinder.
The Hawking temperature in the context of dark energy
Gangopadhyay, Debashis
2012-01-01
An emergent gravity metric incorporating $k-$essence scalar fields $\\phi$ having a Born-Infeld type lagrangian is mapped into a metric whose structure is similar to that of a blackhole of large mass $M$ that has swallowed a global monopole. However, here the field is not that of a monopole but rather that of a $k-$essence scalar field. If $\\phi_{emergent}$ be solutions of the emergent gravity equations of motion under cosmological boundary conditions at $\\infty$, then for $r\\rightarrow\\infty$ the rescaled field $\\frac {\\phi_{emergent}}{2GM-1}$ has exact correspondence with $\\phi$ with $\\phi(r,t)=\\phi_{1}(r)+\\phi_{2}(t)$. The Hawking temperature of this metric is $T_{\\mathrm emergent}= \\frac{\\hbar c^{3}}{8\\pi GM k_{\\mathrm B}}(1-K)^{2}\\equiv \\frac{\\hbar}{8\\pi GM k_{\\mathrm B}}(1-K)^{2}$, taking the speed of light $c=1$. Here $K=\\dot\\phi_{2}^{2}$ is the kinetic energy of the $k-$essence field $\\phi$ and $K$ is always less than unity, $k_{\\mathrm B}$ is the Boltzmann constant. This is phenomenologically interest...
Omega-deformed SYM on a Gibbons-Hawking Space
Dey, Anindya
2014-01-01
We study an $\\mathcal{N}=2$, pure $U(1)$ SYM theory on a Gibbons-Hawking space $\\Omega$-deformed using the $U(1)$ isometry. The resultant 3D theory, after an appropriate "Nekrasov-Witten" change of variables, is asymptotically equivalent to the undeformed theory at spatial infinity but differs from it as one approaches the NUT centers which are fixed points under the $U(1)$ action. The 3D theory may be recast in the form of a generalized hyperk\\"ahler sigma model introduced in \\cite{Dey:2014lja} where the target space is a one-parameter family of hyperk\\"ahler spaces. The hyperk\\"ahler fibers have a preferred complex structure which for the deformed theory depends on the parameter of $\\Omega$-deformation. The metric on the hyperk\\"ahler fiber can be reduced to a standard metric on $\\mathbb{C} \\times T^2$ with the modular parameter of the torus depending explicitly on the $\\Omega$-deformation parameter. The contribution of the NUT center to the sigma model path integral, expected to be a holomorphic section of...
Identifying habitat sinks: A case study of Cooper's hawks in an urban environment
Mannan, R.W.; Steidl, R.J.; Boal, C.W.
2008-01-01
We studied a population of Cooper's hawks (Accipiter cooperii) in Tucson, Arizona from 1994 to 2005. High rates of mortality of nestlings from an urban-related disease prompted speculation that the area represented an ecological trap and habitat sink for Cooper's hawks. In this paper, we used estimates of survival and productivity from 11years of monitoring to develop an estimate of the rate of population change, ??, for Cooper's hawks in the area. We used a Cormack-Jolly-Seber approach to estimate survival of breeding hawks, and a stochastic, stage-based matrix to estimate ??. Despite the urban-related disease, the estimate of ?? indicated that the area does not function as a habitat sink for Cooper's hawks (?? = 1.11 ?? 0.047; P = 0.0073 for the null of ?? 1). Because data required to reliably identify habitat sinks are extensive and difficult to acquire, we suggest that the concept of habitat sinks be applied cautiously until substantiated with reliable empirical evidence. ?? 2008 Springer Science+Business Media, LLC.
“霍金难题”解读%Illumination of ＂Hawking Puzzle＂
王伯鲁
2012-01-01
＂Hawking puzzle＂ has been a technical problem about the future of human race which was brought forward recently by well-known contemporary scientist Stephen Hawking. It has given a broad social impact on the globe. This article has illuminated Hawking puzzle from a philosophical point of view, valued and explained the meaning of Hawking asking. In my opinion, the difficulty of Hawking puzzle are not only to give a 100-year plan to ensure the sustainable development of human race, but also to push implementation effective on this plan.%＂霍金难题＂是当代著名科学家霍金近期提出的一个关于人类前途的技术性难题,产生了广泛的社会影响。从哲学视角解读霍金难题,评说霍金提问的时代意义,其难点不仅表现在不易从技术上给出一个确保人类持续发展的百年规划,而且还在于我们难于推进这一规划的有效实施。
ACES: The ASCENDS CarbonHawk Experiment Simulator
Obland, M. D.; Prasad, N. S.; Harrison, F. W.; Browell, E. V.; Ismail, S.; Dobler, J. T.; Moore, B.; Zaccheo, T.; Campbell, J.; Chen, S.; Cleckner, C. S.; DiJoseph, M.; Little, A.; Notari, A.; Refaat, T. F.; Rosenbaum, D.; Vanek, M. D.; Bender, J.; Braun, M.; Chavez-Pirson, A.; Neal, M.; Rayner, P. J.; Rosiewicz, A.; Shure, M.; Welch, W.
2012-12-01
The ASCENDS CarbonHawk Experiment Simulator (ACES) is a NASA Langley Research Center project funded by NASA's Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) that seeks to advance technologies critical to measuring atmospheric column carbon dioxide (CO2) mixing ratios in support of the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The technologies being advanced are: (1) a high bandwidth detector, (2) a multi-aperture telescope assembly, (3) advanced algorithms for cloud and aerosol discrimination, and (4) high-efficiency, multiple-amplifier CO2 and O2 laser transmitters. The instrument architecture will be developed to operate on a high-altitude aircraft and will be directly scalable to meet the ASCENDS mission requirements. These technologies are viewed as critical towards developing an airborne simulator and eventual spaceborne instrument with lower size, mass, and power consumption, and improved performance. The detector effort will improve the existing detector subsystem by increasing its bandwidth to a goal of 5 MHz, reducing its overall mass from 18 lbs to stretching the duration of autonomous, service-free operation periods from 4 hrs to >24 hrs. The development goals are to permit higher laser modulation rates, which provides greater flexibility for implementing thin-cloud discrimination algorithms as well as improving range resolution and error reduction, and to enable long flights on a high-altitude unmanned aerial vehicle (UAV). The telescope development consists of a three-telescope design built for the constraints of the Global Hawk aircraft. This task addresses the ability of multiple smaller telescopes to provide equal or greater collection efficiency compared with a single larger telescope with a reduced impact on launch mass and cost. The telescope assembly also integrates fiber-coupled transmit collimators for all of the laser transmitters and fiber-coupled optical signal output
BOOK REVIEW: Meilensteine der Astronomie - Von Aristoteles bis Hawking
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
The Hawk-I UDS and GOODS Survey (HUGS): Survey design and deep K-band number counts
Fontana, A.; Dunlop, J. S.; Paris, D.; Targett, T. A.; Boutsia, K.; Castellano, M.; Galametz, A.; Grazian, A.; McLure, R.; Merlin, E.; Pentericci, L.; Wuyts, S.; Almaini, O.; Caputi, K.; Chary, R. R.; Cirasuolo, M.; Conselice, C. J.; Cooray, A.; Daddi, E.; Dickinson, M.; Faber, S. M.; Fazio, G.; Ferguson, H. C.; Giallongo, E.; Giavalisco, M.; Grogin, N. A.; Hathi, N.; Koekemoer, A. M.; Koo, D. C.; Lucas, R. A.; Nonino, M.; Rix, H. W.; Renzini, A.; Rosario, D.; Santini, P.; Scarlata, C.; Sommariva, V.; Stark, D. P.; van der Wel, A.; Vanzella, E.; Wild, V.; Yan, H.; Zibetti, S.
2014-01-01
We present the results of a new, ultra-deep, near-infrared imaging survey executed with the Hawk-I imager at the ESO VLT, of which we make all the data public. This survey, named HUGS (Hawk-I UDS and GOODS Survey), provides deep, high-quality imaging in the K and Y bands over the CANDELS UDS and GOO
The Hawk-I UDS and GOODS Survey (HUGS) : Survey design and deep K-band number counts
Fontana, A.; Dunlop, J. S.; Paris, D.; Targett, T. A.; Boutsia, K.; Castellano, M.; Galametz, A.; Grazian, A.; McLure, R.; Merlin, E.; Pentericci, L.; Wuyts, S.; Almaini, O.; Caputi, K.; Chary, R. -R.; Cirasuolo, M.; Conselice, C. J.; Cooray, A.; Daddi, E.; Dickinson, M.; Faber, S. M.; Fazio, G.; Ferguson, H. C.; Giallongo, E.; Giavalisco, M.; Grogin, N. A.; Hathi, N.; Koekemoer, A. M.; Koo, D. C.; Lucas, R. A.; Nonino, M.; Rix, H. W.; Renzini, A.; Rosario, D.; Santini, P.; Scarlata, C.; Sommariva, V.; Stark, D. P.; van der Wel, A.; Vanzella, E.; Wild, V.; Yan, H.; Zibetti, S.
2014-01-01
We present the results of a new, ultra-deep, near-infrared imaging survey executed with the Hawk-I imager at the ESO VLT, of which we make all the data (images and catalog) public. This survey, named HUGS (Hawk-I UDS and GOODS Survey), provides deep, high-quality imaging in the K and Y bands over th
NASA Airborne Science Network Communications Infrastructure for the Global Hawk UAS
Sorenson, C. E.; Sullivan, D.; van Gilst, D. P.
2010-12-01
This poster describes the network systems and protocols used for instrument interfaces, remote data access, visualization, and instrument control, for the NASA Global Hawk Unmanned Aircraft System. The Global Hawk's wide range required development of automated instrument status monitoring, low-bandwidth communication techniques for high latitudes, and other means. Live instrument data is incorporated into facility-provided web displays, delivered to experimenter ground stations, and accessed from GIS-enabled servers for external applications. Several of the systems incorporated in the Global Hawk Facility were developed as cross-platform projects for NASA Airborne Science, including the on-board data system, telemetry and data server, and the data display web application. Additionally, simple packet formats were developed with the IWGADTS standards group. As such, this infrastructure represents the first instance of the integrated core set of services which are planned to be provided on all the NASA Airborne Science platform aircraft, implementing a science mission support sensor web.
Saini, Anshul
2016-01-01
We study time-dependant Hawking-like radiation as seen by an infalling observer during gravitational collapse of a thin shell. We calculate the occupation number of particles whose frequencies are measured in the proper time of an infalling observer in Eddington-Finkelstein coordinates. We solve the equations for the whole process from the beginning of the collapse till the moment when the collapsing shell reaches zero radius. The radiation distribution is not thermal in the whole frequency regime, but it is approximately thermal for the wavelengths of the order of the Schwarzschild radius of the collapsing shell. After the Schwarzschild radius is crossed, the temperature increases without limits as the singularity is approached. We also calculate the density matrix associated with this radiation. It turns out that the off-diagonal correlation terms to the diagonal Hawking's leading order terms are very important. While the trace of the diagonal (Hawking's) density matrix squared decreases during the evolutio...
Hawking versus Unruh effects, or the difficulty of slowly crossing a black hole horizon
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 fluxes and Anomalies in the Rotating Regular Black Holes with the Time-Delay
Takeuchi, Shingo
2016-01-01
We are going to calculate the flow of the angular momentum and flux of the Hawking radiation in the rotating regular black hole with the time-delay proposed in arXiv:1510.08828, based on the anomaly cancellation. We first try to reduce the field theories to the infinite two-dimensional massless free models in which the anomaly cancellation method is possible, in the three metrics in arXiv:1510.08828. We demonstrate that the two of them can be reduced. We perform the calculation in these two metrics, and obtain the flow of the angular momentum and flux of the Hawking radiation in these two metrics. Our result involves the three effects:~the quantum gravity effect regularizing the gravity sources of the black holes, the black hole rotation, and the time-delay. Hence our result could be considered to correspond to a more realistic Hawking radiations.
Hawking radiation via tunneling from the spacetime of a spinning cosmic string black holes
Jusufi, Kimet
2015-01-01
In this paper, we study Hawking radiation as a massless particles tunneling process across the event horizon from the Schwarzschild and Reissner-Nordstr\\"om black holes pierced by an infinitely long spinning cosmic string and a global monopole. Applying the WKB approximation and using a generalized Painlev\\'e line element for stationary axisymmetric spacetimes, also by taking into account that the ADM mass of the black hole decreases due to the presence of topological defects, it is shown that the Hawking temperature remains unchanged for these black holes. The tunneling of charged massive particles from Reissner-Nordstr\\"om black holes is also studied, in both cases the tunneling rate is related to the change of the Bekenstein-Hawking entropy. The results extend the work of Parikh and Wilczek and are consistent with an underlying unitary theory.
Hawking versus Unruh effects, or the difficulty of slowly crossing a black hole horizon
Barbado, Luis C; Garay, Luis J; Jannes, Gil
2016-01-01
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.
A note on a perfect simulation algorithm for marked Hawkes processes
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 algori......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....
The Hawkes process with different excitation functions and its asymptotoc behavior
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...
More on the conformal mapping of quasi-local masses: The Hawking-Hayward case
Hammad, Fayçal
2016-01-01
The conformal transformation of the Hawking-Hayward quasi-local mass is reexamined. It has been found recently that the conformal transformation of the latter exhibits the 'wrong' conformal factor compared to the way usual masses transform under conformal transformations of spacetime. We show, in analogy with what was found recently for the Misner-Sharp mass, that unlike the purely geometric definition of the Hawking-Hayward mass, the latter exhibits the 'right' conformal factor whenever expressed in terms of its material content via the field equations. The case of conformally invariant scalar-tensor theories of gravity is also examined. The equivalence between the Misner-Sharp mass and the Hawking-Hayward mass for spherically symmetric spacetimes manifests itself by giving identical peculiar behaviors under conformal transformations.
Hawking versus Unruh effects, or the difficulty of slowly crossing a black hole horizon
Barbado, Luis C.; Barceló, Carlos; Garay, Luis J.; Jannes, Gil
2016-10-01
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.
New Form of Kerr-Newman Solution and Its Hawking Radiation via Tunneling
JIANG Qing-Quan; WU Shuang-Qing; YANG Shu-Zheng; CHEN De-You
2006-01-01
Parikh-Wilzcek's recent work, which treats the Hawking radiation as semi-classical tunneling processfrom the event horizon of static Schwarzshild and Reissner-Nordstr(o)m black holes, indicates that the factually radiant spectrum deviates from the precisely thermal spectrum after taking the self-gravitation interaction into account. In this paper, we extend Parikh-Wilzcek's work to research the Hawking radiation via tunneling from new form of rotating Kerr-Newman solution and obtain a corrected radiant spectrum, which is related to the change of Bekenstein-Hawking entropy, and is not pure thermal, but is consistent with the underlying unitary theory. Meanwhile, we point out that the information conservation is only suitable for the reversible process and in highly unstable evaporating black hole (irreversible process) the information loss is possible.
More on the conformal mapping of quasi-local masses: the Hawking-Hayward case
Hammad, Fayçal
2016-12-01
The conformal transformation of the Hawking-Hayward quasi-local mass is re-examined. It has been found recently that the conformal transformation of the latter exhibits the ‘wrong’ conformal factor compared to the way usual masses transform under conformal transformations of spacetime. We show, in analogy with what was found recently for the Misner-Sharp mass, that unlike the purely geometric definition of the Hawking-Hayward mass, the latter exhibits the ‘right’ conformal factor whenever expressed in terms of its material content via the field equations. The case of conformally invariant scalar-tensor theories of gravity is also examined. The equivalence between the Misner-Sharp mass and the Hawking-Hayward mass for spherically symmetric spacetimes manifests itself by giving identical peculiar behaviors under conformal transformations.
Anomalies and Hawking fluxes from the black holes of topologically massive gravity
Porfyriadis, Achilleas P
2009-01-01
The anomaly cancelation 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 cancelation method, are in complete agreement with the ones obtained from integrating the Planck distribution.
Hawking radiation from astrophysical black holes to analogous systems in lab
Belgiorno, Francesco D
2017-01-01
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.
Non-equilibrium Landauer transport model for Hawking radiation from a black hole
Nation, P. D.; Blencowe, M. P.; Nori, Franco
2012-03-01
We propose that the Hawking radiation energy and entropy flow rates from a black hole can be viewed as a one-dimensional (1D), non-equilibrium Landauer transport process. Support for this viewpoint comes from previous calculations invoking conformal symmetry in the near-horizon region, which give radiation rates that are identical to those of a single 1D quantum channel connected to a thermal reservoir at the Hawking temperature. The Landauer approach shows in a direct way the particle statistics independence of the energy and entropy fluxes of a black hole radiating into vacuum, as well as one near thermal equilibrium with its environment. As an application of the Landauer approach, we show that Hawking radiation gives a net entropy production that is 50% larger than that obtained assuming standard 3D emission into vacuum.
The Trilinear Hamiltonian: A Zero Dimensional Model of Hawking Radiation from a Quantized Source
Nation, P D
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. The conditions are derived 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.
The trilinear Hamiltonian: a zero-dimensional model of Hawking radiation from a quantized source
Nation, Paul D; Blencowe, Miles P, E-mail: paul.d.nation@dartmouth.ed [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)
2010-09-15
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.
Drag reduction by wing tip slots in a gliding Harris' hawk, Parabuteo unicinctus
Tucker
1995-01-01
The anterior-most primary feathers of many birds that soar over land bend upwards and separate vertically to form slotted wing tips during flight. The slots are thought to reduce aerodynamic drag, although drag reduction has never been demonstrated in living birds. Wing theory explains how the feathers that form the tip slots can reduce induced drag by spreading vorticity horizontally along the wing and by acting as winglets, which are used on aircraft to make wings non-planar and to spread vorticity vertically. This study uses the induced drag factor to measure the induced drag of a wing relative to that of a standard planar wing with the same span, lift and speed. An induced drag factor of less than 1 indicates that the wing is non-planar. The minimum drag of a Harris' hawk gliding freely in a wind tunnel was measured before and after removing the slots by clipping the tip feathers. The unclipped hawk had 7090 % of the drag of the clipped hawk at speeds between 7.3 and 15.0 m s-1. At a wing span of 0.8 m, the unclipped hawk had a mean induced drag factor of 0.56, compared with the value of 1.10 assumed for the clipped hawk. A Monte Carlo simulation of error propagation and a sensitivity analysis to possible errors in measured and assumed values showed that the true mean value of the induced drag factor for the unclipped hawk was unlikely to be more than 0.93. These results for a living bird support the conclusions from a previous study of a feathered tip on a model wing in a wind tunnel: the feathers that form the slotted tips reduce induced drag by acting as winglets that make the wings non-planar and spread vorticity both horizontally and vertically.
Sakalli, I
2016-01-01
Hawking radiation of charged massive spin-0 particles are studied in the gravitational, electromagnetic, dilaton, and axion fields of rotating linear dilaton black holes. In this geometry, we separate the covariant Klein--Gordon equation into radial and angular parts and obtain the exact solutions of both the equations in terms of the confluent Heun functions. Using the radial solution, we analyze the behavior of the wave solutions near the event horizon of the rotating linear dilaton black hole and derive its Hawking radiation spectrum via the Damour--Ruffini--Sannan method.
Hawking Radiation of Massive Vector Particles From Warped AdS$_{\\text{3}}$ Black Hole
Gursel, H
2015-01-01
Hawking radiation (HR) of massive vector particles from a rotating Warped Anti-de Sitter black hole in 2+1 dimensions (WAdS$_{\\text{3}}$BH) is studied in detail. The quantum tunneling approach with the Hamilton-Jacobi method (HJM) is applied in the Proca equation (PE), and we show that the radial function yields the tunneling rate of the outgoing particles. Comparing the result obtained with the Boltzmann factor, we satisfactorly reproduce the Hawking temperature (HT) of the WAdS$_{\\text{3}}$BH.
YANG Shu-Zheng; CHEN De-You
2007-01-01
@@ Taking the self-gravitation interaction and energy conservation, charge conservation and angular momentum conservation into account, we discuss the tunnelling characteristics of the charged particle from Sen black hole by the Hamilton-Jacobi method. The result shows that the tunnelling probability is related to the change of Bekenstein-Hawking entropy, and the actual radiation spectrum deviates from the pure thermal one, which is consistent with the result of Parikh and Wilczek and gives a new method to correct the Hawking pure thermal spectrum of Sen black hole.
The Hawking radiation of the charged particle via tunnelling from the axisymmetric Sen black hole
Jiang Qing-Quan; Yang Shu-Zheng; Chen De-You
2006-01-01
Extending Parikh's semi-classical quantum tunnelling model, this paper has studied the Hawking radiation of the charged particle via tunnelling from the horizon of the axisymmetric Sen black hole. Different from the uncharged massless particle, the geodesies of the charged massive particle tunnelling from the horizon is not light-like. The derived result supports Parikh's opinion and provides a correct modification to Hawking strictly thermal spectrum developed by the fixed background space-time and not considering the energy conservation and the self-gravitation interaction.
Open quantum system approach to the Gibbons-Hawking effect of de Sitter space-time.
Yu, Hongwei
2011-02-11
We analyze, in the paradigm of open quantum systems, the reduced dynamics of a freely falling two-level detector in de Sitter space-time in weak interaction with a reservoir of fluctuating quantized conformal scalar fields in the de Sitter-invariant vacuum. We find that the detector is asymptotically driven to a thermal state at the Gibbons-Hawking temperature, regardless of its initial state. Our discussion, therefore, shows that the Gibbons-Hawking effect of de Sitter space-time can be understood as a manifestation of thermalization phenomena that involves decoherence and dissipation in open quantum systems.
Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation.
Eilenberger, Falk; Kabakova, Irina V; de Sterke, C Martijn; Eggleton, Benjamin J; Pertsch, Thomas
2013-01-01
We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations.
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.
Hawking radiation of charged Dirac particles in Vaidya-Bonner space-time
朱建阳; 张建华; 赵峥
1995-01-01
The dynamical properties of charged Dirac spinor particles in the Vaidya-Bonner space-time are investigated. The asymptotic solution to the radial part of the charged Dirac equation near the event horizon of the black hole is obtained. The Hawking temperature and the event horizon of the charged evaporating black hole, as well as the spectrum of the Hawking radiation of the Dirac particles, are exactly shown. Thereby, a new approach to the back-reaction of radiation from the non-stationary black holes is established.
Correction to Hawking Radiation Characteristics of Stationary Demianski-Newman Black Hole
JIANG Qing-Quan; YANG Shu-Zheng
2006-01-01
The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneling rate of the particle is relevant to Bekenstein-Hawking entropy, and the derived radiate spectrum is not strictly pure thermal,but is consistent with underlying unitary theory. Finally, we use the obtained results to reduce to stationary Kerr black hole and static Schwarzschild black hole, and find that only when ignoring the spectrum at higher energies is the tunneling radiation spectrum consistent with Hawking pure thermal one.
Hawking Radiation of a Kaluza-Klein Black Hole Described by Landauer Transport Model
兰小刚; 韦联福
2012-01-01
We investigate the Hawking radiation of a Kaluza-Klein black hole by using one-dimensional(1D),non-equilibrium,Landauer transport model.The derived Hawking radiation temperature is in consistence with that obtained by using the usual anomaly method.With the Landauer transport model,we calculate the entropy flow out of the Kaluza-Klein black hole and the relevant entropy production rate.How these quantities depending on the physical parameters of the black hole is also discussed.
The loss of the entanglement between Hawking pairs due to a black hole singularity
Oshita, Naritaka
2016-01-01
We propose that the entanglement of Hawking pairs disappears due to redshift of the infalling mode in the vicinity of a black hole singularity. More concretely, the infalling mode is redshifted as it falls away from the horizon and decoheres, which makes the state of the Hawking pair separable, namely the entanglement is broken. This implies we no longer need to introduce the firewalls to avoid the firewall paradox. In other words, we do not need to abandon any of the fundamental principle, i.e., Einstein's equivalence principle, unitarity, and quantum field theory.
Coordinates Used in Derivation of Hawking Radiation via Hamilton-Jacobi Method
Liu, Bo; He, Xiaokai; Liu, Wenbiao
2009-05-01
Coordinates used in derivation of Hawking radiation via Hamilton-Jacobi method are investigated more deeply. In the case of a 4-dimensional Schwarzschild black hole, a direct computation leads to a wrong result. In the meantime, making use of the isotropic coordinate or invariant radial distance, we can get the correct conclusion. More coordinates including Painleve and Eddington-Finkelstein are tried to calculate the semi-classical Hawking emission rate. The reason of the discrepancy between naive coordinate and well-behaved coordinates is also discussed.
Tortoise Coordinates and Hawking Radiation in a Dynamical Spherically Symmetric Spacetime
YANG Jian; ZHAO Zheng; TIAN Gui-Hua; LIU Wen-Biao
2009-01-01
Hawking effect from dynamical spherical Vaidya black hole,Vaidya-Bonner black hole,and Vaidya-de Sitter black hole is investigated using the improved Damour-Ruffini method.After the new tortoise coordinate transformation in which the position τ of event horizon is an undetermined function and the temperature parameter κ is an undetermined constant,the Klein-Gordon equation can be written as the standard form at the event horizon,and both τ and κ can be determined automatically.Then extending the outgoing wave from outside to inside of the horizon analytically,the Hawking temperature can also be obtained automatically.
Hawking radiation from the charged and magnetized BTZ black hole via covariant anomaly
Zeng Xiao-Xiong; Yang Shu-Zheng
2009-01-01
This paper discusses Hawking radiation from the charged and magnetized Bafiados-Teitelboim-Zanelli (BTZ) black hole from the viewpoint of anomaly, initiated by Robinson and Wilczek recently. It reconstructs the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges to redefine an equivalent charge and gauge potential. It employs the covariant anomaly cancellation method to determine thecompensating fluxes of charge flow and energy-momentum tensor, which are shown to match with those of the 2- dimensional blackbody radiation at the Hawking temperature exactly.
Remarks on Hawking radiation as tunneling from a uniformly accelerating black hole
Xiao-Xiong Zeng; Jian-Song Hou; Shu-Zheng Yang
2008-03-01
Motivated by the Hamilton-Jacobi method of Angheben et al, we investigate the Hawking tunneling radiation from a uniformly accelerating rectilinear black hole for which the horizons and entropy are functions of . After several coordinate transformations, we conclude that when the self-gravitational interaction and energy conservation are taken into account, the actual radiation spectrum deviates from the thermal one and the tunneling rate is the function of though it is still related to the change of the Bekenstein-Hawking entropy.
Addendum: Hawking Radiation of Photons in a Variable-mass Kerr Black Hole
S. Q. Wu; Cai, X
2001-01-01
Hawking evaporation of photons in a variable-mass Kerr space-time is investigated by using a method of the generalized tortoise coordinate transformation. The blackbody radiant spectrum of photons displays a new spin-rotation coupling effect obviously dependent on different helicity states of photons.
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
Energy shift of H-atom electrons due to Gibbons-Hawking thermal bath
Pardy, Miroslav
2016-01-01
The electromagnetic shift of energy levels of H-atom electrons is determined by calculating an electron coupling to the Gibbons-Hawking electromagnetic field thermal bath. Energy shift of electrons in H-atom is determined in the framework of the non-relativistic quantum mechanics.
Non-Thermal Corrections to Hawking Radiation Versus the Information Paradox
Dvali, Gia
2015-01-01
We provide a model-independent argument indicating that for a black hole of entropy N the non-thermal deviations from Hawking radiation, per each emission time, are of order 1/N, as opposed to exp(-N). This fact abolishes the standard a priory basis for the information paradox.
Gravitational instantons of type $D_k$ and a generalization of the Gibbons-Hawking Ansatz
Ionas, Radu A
2016-01-01
We describe a quaternionic-based Ansatz generalizing the Gibbons-Hawking Ansatz to a class of hyperk\\"ahler metrics with hidden symmetries. We then apply it to obtain explicit expressions for gravitational instanton metrics of type $D_k$.
Dynamics of the echolocation beam during prey pursuit in aerial hawking bats
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...
Hawking Radiation of Dirac Particles on Rindler Horizon to a Uniformly Accelerating Observer
ZHANGJinK-Yi
2003-01-01
Following the method of Damour and Ruffini, the Hawking radiation of Dirac particles on Rindler horison to a uniformly accelerating observer is studied this paper. The temperature on Rindler horizon surface and the thermal spectrum formula of Dirac particles are obtained. The result is discussed.
Hawking Radiation of Dirac Particles on Rindler Horizon to a Uniformly Accelerating Observer
ZHANG Jing-Yi
2003-01-01
Following the method of Damour and Ruffini, the Hawking radiation of Dirac particles on Rindler horizonto a uniformly accelerating observer is studied in this paper. The temperature on Rindler horizon surface and the thermalspectrum formula of Dirac particles are obtained. The result is discussed.
Back reaction, the Hawking emission spectrum from the charged black hole
Xu Pingchuan; Wang Zhihong [Institute of Theoretical Physics, China West Normal University, Nanchong, Sichuan 637002 (China); Han Yan, E-mail: pcxu@163.com [College of Mathematic and Information, China West Normal University, Nanchong, Sichuan 637002 (China)
2011-06-21
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{sub {mu}{nu}}({phi}, g{sub {mu}{nu}})). 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.
Organophosphate insecticide (famphur) topically applied to cattle kills magpies and hawks
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.
Decreases in a Population of Red-Shouldered Hawks Nesting in Central Maryland
US Fish and Wildlife Service, Department of the Interior — This outlines the results of a 32 year nesting study of the Red-shouldered Hawk in central Maryland that adds 31 years of observations to an earlier long-term study....
HawkEye: CubeSat SeaWiFS update
Schueler, Carl; Holmes, Alan
2016-09-01
The SeaHawk 3U CubeSat program is funded by the Gordon and Betty Moore Foundation of San Francisco, and managed by John Morrison of the University of North Carolina-Wilmington (UNC-W). Cloudland Instruments is developing HawkEye for SeaHawk. HawkEye is a multispectral ocean color imager of SeaWiFS quality with 120 meter nadir resolution from an orbit altitude of 540 km to provide observation of sub-mesoscale variability for insights into poorly understood mixing dynamics. 120 meter imagery improves ability, relative to SeaWiFS 1km resolution, to monitor fjords, estuaries, coral reefs and other near-shore environments where anthropogenic stresses are often most acute and where there are considerable security and commercial interests. The optics, filters, and arrays comprise a cube 10 cm on a side to fit a 3U CubeSat manufactured by ClydeSpace of Glasgow Scotland, and provide a 350 km swath cross-track.
Evaluating the release of a large store from the BAE Hawk Mk120
Jamison, Kevin
2010-11-01
Full Text Available The analysis of the release of a large store from the outboard pylon of the BAE Hawk Mk120 is described as a case study. The process adopted to address this challenge included using both the ARUV panel code and the CFD-FASTRAN Navier...
Hawking radiation from Kerr-Newman-Kasuya black hole via quantum anomalies
He Tang-Mei; Fan Jun-Hui; Wang Yong-Jiu
2008-01-01
We have studied the Hawking radiation of the Kerr-Newman-Kasuya black hole via gauge and gravitational anomaly in the dragging coordinates. The fluxes of the electromagnetic current and the energy momentum tensor for each partial wave in two-dimensional field are obtained.
75 FR 6625 - Dixie National Forest, UT, Kitty Hawk Administrative Site Master Development Plan
2010-02-10
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Dixie National Forest, UT, Kitty Hawk Administrative Site Master Development Plan AGENCY: Forest Service, USDA. ACTION: Notice of Intent to Prepare an Environmental Impact Statement. SUMMARY:...
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.
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.
Hossain, M Ilias
2013-01-01
Incorporating Parikh and Wilczek's opinion to the Kerr de-Sitter (KdS) black hole Hawking non-thermal and purely thermal radiations have been investigated using Hamilton-Jacobi method. We have taken the background spacetime of KdS black hole as dynamical, involving the self-gravitation effect of the emitted particles, energy and angular momentum has been taken as conserved and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The explored results gives a correction to the Hawking radiation of KdS black hole.
US Fish and Wildlife Service, Department of the Interior — Table 1 provides the results of organochlorine and mercury analysis on plasma and whole blood samples (respectively) collected from 20 sharp-shinned hawks at HMS...
Grišins, Pjotrs; Nguyen, Hai Son; Bloch, Jacqueline; Amo, Alberto; Carusotto, Iacopo
2016-10-01
We propose an experiment to detect and characterize the analog Hawking radiation in an analog model of gravity consisting of a flowing exciton-polariton condensate. Under a suitably designed coherent pump configuration, the condensate features an acoustic event horizon for sound waves that at the semiclassical level is equivalent to an astrophysical black-hole horizon. We show that a continuous-wave pump-and-probe spectroscopy experiment allows to measure the analog Hawking temperature from the dependence of the stimulated Hawking effect on the pump-probe detuning. We anticipate the appearance of an emergent resonant cavity for sound waves between the pump beam and the horizon, which results in marked oscillations on top of an overall exponential frequency dependence. We finally analyze the spatial correlation function of density fluctuations and identify the hallmark features of the correlated pairs of Bogoliubov excitations created by the spontaneous Hawking process, as well as novel signatures characterizing the emergent cavity.
Chakraborty, Subenoy; Saha, Subhajit; Corda, Christian
2016-01-01
The present work deals with the semi-classical tunnelling approach and the Hamilton-Jacobi method to study Hawking radiation from the dynamical horizon of both the homogeneous Friedmann-Robertson-Walker (FRW...
LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Using anomalous viewpoint,we study the Hawking radiation from a kind of topological Kerr Anti-de-Sitter(Kerr AdS)black hole with ode rotational parameter.We employ the covariant gauge and gravitational anomalies.The result supports the Robinson-Wilczek opinion and shows that the Hawking temperature can be correctly determined by cancelling covariant gauge and gravitational anomalies at the horizon.
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.
Towards the observation of Hawking radiation in Bose--Einstein condensates
Barcelo, C; Visser, M; Barcelo, Carlos; Liberati, Stefano; Visser, Matt
2001-01-01
Acoustic analogues of black holes (dumb holes) are generated when a supersonic fluid flow entrains sound waves and forms a trapped region from which sound cannot escape. The surface of no return, the acoustic horizon, is qualitatively very similar to the event horizon of a general relativity black hole. In particular Hawking radiation (a thermal bath of phonons with temperature proportional to the ``surface gravity'') is expected to occur. In this note we consider quasi-one-dimensional supersonic flow of a Bose--Einstein condensate (BEC) in a Laval nozzle (converging-diverging nozzle), with a view to finding which experimental settings could magnify this effect and provide an observable signal. We identify an experimentally plausible configuration with a Hawking temperature of order 70 n K; to be contrasted with a condensation temperature of the order of 90 n K.
Quantum Noise in Amplifiers and Hawking/Dumb-Hole Radiation as Amplifier Noise
Unruh, W G
2011-01-01
The quantum noise in a linear amplifier is shown to be thermal noise. The theory of linear amplifiers is applied first to the simplest, single or double oscillator model of an amplifier, and then to linear model of an amplifier with continuous fields and input and outputs. Finally it is shown that the thermal noise emitted by black holes first demonstrated by Hawking, and of dumb holes (sonic and other analogs to black holes), arises from the same analysis as for linear amplifiers. The amplifier noise of black holes acting as amplifiers on the quantum fields living in the spacetime surrounding the black hole is the radiation discovered by Hawking. For any amplifier, that quantum noise is completely characterized by the attributes of the system regarded as a classical amplifier, and arises out of those classical amplification factors and the commutation relations of quantum mechanics.
Mechanism of stimulated Hawking radiation in a laboratory Bose-Einstein condensate
Wang, Yi-Hsieh; Jacobson, Ted; Edwards, Mark; Clark, Charles W.
2017-08-01
We model a sonic black-hole analog in a quasi-one-dimensional Bose-Einstein condensate, using a Gross-Pitaevskii equation matching the configuration of a recent experiment by Steinhauer [Nat. Phys. 10, 864 (2014), 10.1038/nphys3104]. The model agrees well with important features of the experimental observations, demonstrating their hydrodynamic nature. We find that a zero-frequency bow wave is generated at the inner (white-hole) horizon, which grows in proportion to the square of the background condensate density. The relative motion of the black- and white-hole horizons produces a Doppler shift of the bow wave at the black hole, where it stimulates the emission of monochromatic Hawking radiation. The mechanism is confirmed using temporal and spatial windowed Fourier spectra of the condensate. Mean field behavior similar to that in the experiment can thus be fully explained without the presence of self-amplifying Hawking radiation.
Maxwell’s Equal Area Law and the Hawking-Page Phase Transition
Euro Spallucci
2013-01-01
Full Text Available We study the phases of a Schwarzschild black hole in the Anti-deSitter background geometry. Exploiting fluid/gravity duality, we construct the Maxwell equal area isotherm in the temperature-entropy plane, in order to eliminate negative heat capacity BHs. The construction we present here is reminiscent of the isobar cut in the pressure-volume plane which eliminates unphysical part of the Van der Walls curves below the critical temperature. Our construction also modifies the Hawking-Page phase transition. Stable BHs are formed at the temperature , while pure radiation persists for . turns out to be below the standard Hawking-Page temperature and there are no unstable BHs as in the usual scenario. Also, we show that, in order to reproduce the correct BH entropy , one has to write a black hole equation of state, that is, , in terms of the geometrical volume .
Jiang Qing-Quan; Yang Shu-Zheng; Wu Shuang-Qing
2006-01-01
This paper extends Parikh-Wilzcek's recent work, which treats the Hawking radiation as a semi-classical tunnelling process from the event horizon of four dimensional Schwarzshild and Reissner-Nordstr(o)m black holes, to that of arbitrarily dimensional Reissner-Nordstr(o)m de Sitter black hole. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the factually radiant spectrum is no longer precisely thermal after taking the dynamical black hole background and energy conservation into account, but is consistent with the underlying unitary theory and then satisfies the first law of the black hole thermodynamics. Meanwhile, in Parikh-Wilzcek's framework, this paper points out that the information conservation is only suitable for the reversible process but in highly unstable evaporating black hole (irreversible process) the information loss is possible.
Emergent horizon, Hawking radiation and chaos in the collapsed polymer model of a black hole
Brustein, Ram
2016-01-01
We have proposed that the interior of a macroscopic Schwarzschild black hole (BH) consists of highly excited, long, closed, interacting strings and, as such, can be modeled as a collapsed polymer. It was previously shown that the scaling relations of the collapsed-polymer model agree with those of the BH. The current paper further substantiates this proposal with an investigation into some of its dynamical consequences. In particular, we show that the model predicts, without relying on gravitational effects, an emergent horizon. We further show that the horizon fluctuates quantum mechanically as it should and that the strength of the fluctuations is inversely proportional to the BH entropy. It is then demonstrated that the emission of Hawking radiation is realized microscopically by the quantum-induced escape of small pieces of string, with the rate of escape and the energy per emitted piece both parametrically matching the Hawking temperature. We also show, using standard methods from statistical mechanics a...
Hawking Radiation of Mass Generating Particles From Dyonic Reissner Nordstrom Black Hole
Sakalli, I
2016-01-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordstr\\"{o}m black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed to read the standard Hawking temperature of the dyonic Reissner-Nordstr\\"{o}m black hole.
Analogy of QCD hadronization and Hawking-Unruh radiation at NICA
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.)
Hawking, fiducial, and free-fall temperature of black hole on gravity's rainbow
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.)
Horizon in random matrix theory, the Hawking radiation, and flow of cold atoms.
Franchini, Fabio; Kravtsov, Vladimir E
2009-10-16
We propose a Gaussian scalar field theory in a curved 2D metric with an event horizon as the low-energy effective theory for a weakly confined, invariant random matrix ensemble (RME). The presence of an event horizon naturally generates a bath of Hawking radiation, which introduces a finite temperature in the model in a nontrivial way. A similar mapping with a gravitational analogue model has been constructed for a Bose-Einstein condensate (BEC) pushed to flow at a velocity higher than its speed of sound, with Hawking radiation as sound waves propagating over the cold atoms. Our work suggests a threefold connection between a moving BEC system, black-hole physics and unconventional RMEs with possible experimental applications.
Violation of unitarity by Hawking radiation does not violate energy-momentum conservation
Nikolic, H
2015-01-01
An argument by Banks, Susskind and Peskin (BSP), according to which violation of unitarity would violate either locality or energy-momentum conservation, is widely believed to be a strong argument against non-unitarity of Hawking radiation. We find that the whole BSP argument rests on the crucial assumption that the Hamiltonian is not highly degenerate, and point out that this assumption is wrong. Using Lindblad equation, we show that high degeneracy of the Hamiltonian allows local non-unitary evolution without violating energy-momentum conservation. Moreover, since energy-momentum is the source of gravity, we argue that energy-momentum is necessarily conserved for a large class of non-unitary systems with gravity. Finally, we explicitly calculate the Lindblad operators for non-unitary Hawking radiation and show that they conserve energy-momentum.
Violation of unitarity by Hawking radiation does not violate energy-momentum conservation
Nikolić, Hrvoje [Theoretical Physics Division, Rudjer Bošković Institute, P.O.B. 180, HR-10002 Zagreb (Croatia)
2015-04-02
An argument by Banks, Susskind and Peskin (BSP), according to which violation of unitarity would violate either locality or energy-momentum conservation, is widely believed to be a strong argument against non-unitarity of Hawking radiation. We find that the whole BSP argument rests on the crucial assumption that the Hamiltonian is not highly degenerate, and point out that this assumption is not satisfied for systems with many degrees of freedom. Using Lindblad equation, we show that high degeneracy of the Hamiltonian allows local non-unitary evolution without violating energy-momentum conservation. Moreover, since energy-momentum is the source of gravity, we argue that energy-momentum is necessarily conserved for a large class of non-unitary systems with gravity. Finally, we explicitly calculate the Lindblad operators for non-unitary Hawking radiation and show that they conserve energy-momentum.
Hawking temperature: an elementary approach based on Newtonian mechanics and quantum theory
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.
Universal Property of Quantum Gravity implied by Bekenstein-Hawking Entropy and Boltzmann formula
Saida, Hiromi
2013-01-01
We search for a universal property of quantum gravity. By "universal", 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 equat...
Hawking Radiation of Mass Generating Particles from Dyonic Reissner–Nordström Black Hole
I. Sakalli; A Ovgun
2016-09-01
The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton--Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyse the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton--Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner--Nordström black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed in reading the standard Hawking temperature of the dyonic Reissner–Nordström black hole.
Entanglement in a model for Hawking radiation: An Application of Quadratic Algebras
Bambah, Bindu A; Shreecharan, T; Prasad, K Siva
2012-01-01
Quadratic polynomially deformed $su(1,1)$ and $su(2)$ algebras are utilised 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. Lastly, we study the phenomenon of superradiance in our model in analogy with atomic Dicke superradiance.
From wormhole to time machine Comments on Hawking's Chronology Protection Conjecture
Visser, B M
1993-01-01
The recent interest in ``time machines'' has been largely fueled by the apparent ease with which such systems may be formed in general relativity, given relatively benign initial conditions such as the existence of traversable wormholes or of infinite cosmic strings. This rather disturbing state of affairs has led Hawking to formulate his Chronology Protection Conjecture, whereby the formation of ``time machines'' is forbidden. This paper will use several simple examples to argue that the universe appears to exhibit a ``defense in depth'' strategy in this regard. For appropriate parameter regimes Casimir effects, wormhole disruption effects, and gravitational back reaction effects all contribute to the fight against time travel. Particular attention is paid to the role of the quantum gravity cutoff. For the class of model problems considered it is shown that the gravitational back reaction becomes large before the Planck scale quantum gravity cutoff is reached, thus supporting Hawking's conjecture.
Reproductive Strategies of Northern Goshawks and Cooper's Hawks in North-Central New Mexico
Kennedy, Patricia L.
1991-01-01
I assumed that the reproductive strategies of the two Accipiter species investigated in this study, the northern Goshawk (A. gentilis) and the Cooper's hawk (A. cooperii), would be similar to the strategies of other monogamous raptors with sex role partitioning. Any differences in the species' reproductive strategies, particularly hunting strategies, were expected to be a function of their size differences. Contrary to predictions, results indicated that, in north-central New Mexico during br...
Non-thermal corrections to Hawking radiation versus the information paradox
Dvali, Gia [Arnold Sommerfeld Center for Theoretical Physics, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY (United States)
2016-01-15
We provide a model-independent argument indicating that for a black hole of entropy N the non-thermal deviations from Hawking radiation, per each emission time, are of order 1/N, as opposed to e{sup -N}. This fact abolishes the standard a priory basis for the information paradox. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Corrected Hawking Radiation of Dirac Particles from a General Static Riemann Black Hole
Ge-Rui Chen
2013-01-01
Full Text Available Considering energy conservation and the back reaction of radiating particles to the spacetime, we investigate the massive Dirac particles' Hawking radiation from a general static Riemann black hole using improved Damour-Ruffini method. A direct consequence is that the radiation spectrum is not strictly thermal. The correction to the thermal spectrum is consistent with an underlying unitary quantum theory and this may have profound implications for the black hole information loss paradox.
Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.
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
HAN Yi-Wen; YANG Shu-Zheng
2005-01-01
@@ We extend Parikh's recent work to Schwarzchild-anti-de Sitter black hole with topological defect whose ArnowittDeser-Misner (ADM) mass is no longer identical to its mass parameter. We view the Hawking radiation as a tunnelling process across the event horizon and the cosmological horizon. From the tunnelling probability, we find a leading correction to the semi-classical emission rate. The result employs an underlying unitary theory.
吴双清; 闫沐霖
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated using a method of the generalized tortoise coordinate transformation.Both the location and temperature of the event horizon depend on the time and on the angles.They are in agreement with the previous results,but thethermal radiation spectrum of massless spinor particles displays a type of spin-acceleration coupling effect.
The Hawking-Penrose singularity theorem for $C^{1,1}$-Lorentzian metrics
Graf, Melanie; Grant, James D. E.; Kunzinger, Michael; Steinbauer, Roland
2017-01-01
We show that the Hawking--Penrose singularity theorem, and the generalisation of this theorem due to Galloway and Senovilla, continue to hold for Lorentzian metrics that are of $C^{1, 1}$-regularity. We formulate appropriate weak versions of the strong energy condition and genericity condition for $C^{1,1}$-metrics, and of $C^0$-trapped submanifolds. By regularisation, we show that, under these weak conditions, causal geodesics necessarily become non-maximising. This requires a detailed analy...
Hawk eyes II: diurnal raptors differ in head movement strategies when scanning from perches.
Colleen T O'Rourke
Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS: 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.
NASA Global Hawk Project Update and Future Plans: A New Tool for Earth Science Research
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.
Modified Hawking temperature and entropic force: a prescription in FRW model
Mitra, Saugata; Chakraborty, Subenoy
2016-01-01
The idea of Verlinde that gravity is an entropic force caused by information changes associated with the positions of material bodies, is used in the present work for the FRW model of the Universe. Using modified Hawking temperature, the Friedmann equations are derived on any horizon. For the validity of the first law of thermodynamics (i.e., Clausius relation) it is found that there is modification of Bekenstein entropy on the horizon. However, using equipartition law of energy, Bekenstein entropy is recovered.
High frequency of extra-pair paternity in an urban population of Cooper's Hawks
Rosenfield, Robert N.; Sonsthagen, Sarah A.; Stout, William C.; Talbot, Sandra
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.
Saturating The Bekenstein-Hawking Entropy Bound With Initial Data Sets For Gravitational Collapse
Bahrami, Sina
2016-01-01
It is possible to find initial states for gravitational collapse whose entropy approximately saturates the Bekenstein-Hawking entropy of the final black hole. The prototypical example of such a state is that envisaged by Zurek and Thorne, and also by Susskind: for a black hole of mass $\\sim M$ , a number $\\sim M^2$ of quanta with energies of order $1/M$ are accreted on a timescale of order $\\sim M^3$, an approximate time-reverse of Hawking evaporation. There is lore that all initial states which saturate the Bekenstein-Hawking entropy must involve a formation timescale of this order, $M^3$ , and not the much shorter dynamical timescale $M$ . Counterexamples to this lore have been found by Sorkin, Wald and Zhang, and also by Hsu and Reeb, in the form of semiclassical initial data sets. However the spacetimes that correspond to these counterexamples posses white holes in the past, as well as black holes in the future, which casts doubt on their physical relevance. We modify the counterexamples to eliminate the ...
Saturating the Bekenstein-Hawking entropy bound with initial data sets for gravitational collapse
Bahrami, Sina
2017-01-01
It is possible to find initial states for gravitational collapse whose entropy approximately saturates the Bekenstein-Hawking entropy of the final black hole. The prototypical example of such a state is that envisaged by Zurek and Thorne, and also by Susskind: for a black hole of mass M , a number ˜M2 of quanta with energies of order ˜M-1 are accreted on a time scale of order ˜M3 , an approximate time-reverse of Hawking evaporation. There is lore that all initial states which saturate the Bekenstein-Hawking entropy must involve a formation time scale of this order, ˜M3 , and not the much shorter dynamical time scale ˜M . Counterexamples to this lore have been found by Sorkin, Wald and Zhang, and also by Hsu and Reeb, in the form of semiclassical initial data sets. However, the spacetimes that correspond to these counterexamples possess white holes in the past, as well as black holes in the future, which casts doubt on their physical relevance. We modify the counterexamples to eliminate the white holes, yielding formation time scales of order ˜M2, and argue that the lore is unfounded.
de Nova, J R M
2015-01-01
The work is divided in three parts. We devote the first part to the study of analog Hawking radiation in Bose-Einstein condensates. We study numerically the birth of a sonic black hole in an outcoupled Bose-Einstein condensate after relaxing the confinement provided by an optical lattice. We also study possible signatures of spontaneous Hawking radiation. We propose that the violation of CS inequalities is a smoking gun of the presence of the Hawking effect. We compare this criterion with the presence of entaglement, finding that both are equivalent under usual assumptions. Finally, we study a different gravitational analogue: the so-called black-hole laser. The most interesting result is the appearance of a regime of continuous and periodic emission of solitons, providing the most strong analogue with optical lasers. In the second part, we analyze the effect of the introduction of a short Bragg pulse in a thermal cloud. We show that the induced periodic density pattern decays to the equilibrium profile. Howe...
Nagatani, Y
2001-01-01
We show that a spherical electroweak domain wall is formed around a small black hole and this is a general property of the Hawking radiation in the vacuum of the Standard Model. The wall appears not only for the first order phase transition in the electroweak theory but also for the second order one because the black hole heats up its neighborhood locally by the Hawking radiation in any case. We propose a model for unifying the origin of the baryon number and the cold dark matter in our universe by using properties of the primordial black hole with a mass of several hundred kilograms. The interaction between our wall and the Hawking-radiated-particles can create a baryon number which is proportional to the mass of the black hole as well as the CP broken phase in the extension of the Standard Model. Our model can explain both the baryon-entropy ratio B/S \\sim 10^{-10} and the energy density of the dark matter, provided that the following three conditions are satisfied: (i) the primordial black holes dominate i...
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).
W∞ algebras, Hawking radiation, and information retention by stringy black holes
Ellis, John; Mavromatos, Nick E.; Nanopoulos, D. V.
2016-07-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (the singular regions of which are represented by appropriate Wess-Zumino-Witten models) is retained by quantum W symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole requires a contribution from W∞ generators in its vertex function. The latter correspond to delocalized, nonpropagating, string excitations that guarantee the transfer of information between the string black hole and external particles. When infalling matter crosses the horizon, these topological states are excited via a process: (stringy black hole) + infalling matter → (stringy black hole)⋆ , where the black hole is viewed as a stringy state with a specific configuration of W∞ charges that are conserved. Hawking radiation is then the reverse process, with conservation of the W∞ charges retaining information. The Hawking radiation spectrum near the horizon of a Schwarzschild or Kerr black hole is specified by matrix elements of higher-order currents that form a phase-space W1 +∞ algebra. We show that an appropriate gauging of this algebra preserves the horizon two-dimensional area classically, as expected because the latter is a conserved Noether charge.
On the paradox of Hawking radiation in a maximally extended Schwarzschild solution
Ellis, George F R
2013-01-01
This paper considers the effect of Hawking radiation on an eternal black hole - that is. a maximally extended Schwarzschild solution. Symmetry considerations that hold independent of the details of the emission mechanism show there is an inconsistency in the claim that such a blackhole evaporates away in a finite time. In essence: because the external domain is static, there is an infinite time available for the process to take place, so whenever the evaporation process is claimed to come to completion, it should have happened earlier. The problem is identified to lie in the claim that the locus of emission of Hawking radiation lies just outside the globally defined event horizon. Rather, the emission domain must be mainly located inside the event horizon, so most of the Hawking radiation ends up at this singularity rather than at infinity and the black hole never evaporates away. This result supports a previous claim [arXiv:1310.4771] that astrophysical black holes do not evaporate.
An aerial-hawking bat uses stealth echolocation to counter moth hearing.
Goerlitz, Holger R; ter Hofstede, Hannah M; Zeale, Matt R K; Jones, Gareth; Holderied, Marc W
2010-09-14
Ears evolved in many nocturnal insects, including some moths, to detect bat echolocation calls and evade capture [1, 2]. Although there is evidence that some bats emit echolocation calls that are inconspicuous to eared moths, it is difficult to determine whether this was an adaptation to moth hearing or originally evolved for a different purpose [2, 3]. Aerial-hawking bats generally emit high-amplitude echolocation calls to maximize detection range [4, 5]. Here we present the first example of an echolocation counterstrategy to overcome prey hearing at the cost of reduced detection distance. We combined comparative bat flight-path tracking and moth neurophysiology with fecal DNA analysis to show that the barbastelle, Barbastella barbastellus, emits calls that are 10 to 100 times lower in amplitude than those of other aerial-hawking bats, remains undetected by moths until close, and captures mainly eared moths. Model calculations demonstrate that only bats emitting such low-amplitude calls hear moth echoes before their calls are conspicuous to moths. This stealth echolocation allows the barbastelle to exploit food resources that are difficult to catch for other aerial-hawking bats emitting calls of greater amplitude.
Effect of sublethal lead exposure on gastric motility of red-tailed hawks.
Lawler, E M; Duke, G E; Redig, P T
1991-07-01
In order to determine the effects of low level lead exposure on gastric motility in raptors, strain gage transducers were surgically implanted on the serosal surface of the muscular stomach of three red-tailed hawks. The frequency and amplitude of gastric contractions during ingestion and early digestion were monitored for 1 week under control conditions and for 3 weeks while the birds were fed 0.82 or 1.64 mg lead (as lead acetate) per kg body weight each day. Exposure to these doses did not appreciably affect either the frequency or amplitude of gastric contractions in these birds. This low level lead exposure also had no consistent effect on the regular egestion of pellets of undigested material by hawks. Daily exposure to doses up to 6.55 mg lead/kg body weight did not affect the frequency or timing of pellet egestion, and exposure to 1.64 mg lead/kg did not affect the gastric contractions associated with pellet egestion. Although gastrointestinal dysfunction is often associated with clinical cases of acute lead toxicity, chronic exposure to these low levels of lead acetate did not significantly alter gastric motility in red-tailed hawks.
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
The B4 school check behaviour measures: findings from the Hawke's Bay evaluation.
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.
Naji, J.
2016-01-01
In this paper, we considered new solutions for four-dimensional asymptotically AdS black holes with scalar hair and discuss about Hawking temperature in the context of dark energy by using the tunneling method. We obtain modification of the Hawking temperature due to presence of the dark energy.
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.
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.
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.
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.
Sakalli, I
2013-01-01
Hawking radiation of a non-asymptotically flat (NAF) 4-dimensional spherically symmetric and static dilatonic black hole (BH) via the Hamilton-Jacobi (HJ) method has been studied. In addition to the naive coordinates, we have used four more different coordinate systems which are well-behaved at the horizon. Except the isotropic coordinates, direct computation of the HJ method leads us the standard Hawking temperature for all coordinate systems. The isotropic coordinates render possible to get the index of refraction extracting from the Fermat metric. It is explicitly shown that the index of refraction determines the value of the tunneling rate and its natural consequence, Hawking temperature. The isotropic coordinates within the conventional HJ method produce wrong result for the temperature of the LDBH. Here, we explain how this discrepancy can be resolved by regularizing the integral possessing a pole at the horizon.
Rahman, M Atiqur
2013-01-01
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and gives a correction to the Hawking radiation of SAdS black hole.
Rahman, M. Atiqur; Hossain, M. Ilias
2013-06-01
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SAdS black hole.
On arithmetic detection of grey pulses with application to Hawking radiation
Rosu, H C
2002-01-01
Micron-sized black holes do not necessarily have a constant horizon temperature distribution. The black hole remote-sensing problem means to find out the `surface' temperature distribution of a small black hole from the spectral measurement of its (Hawking) grey pulse. This problem has been previously considered by Rosu, who used Chen's modified Moebius inverse transform. Here, we hint on a Ramanujan generalization of Chen's modified MOebius inverse transform that may be considered as a special wavelet processing of the remote-sensed grey signal coming from a black hole or any other distant grey source
Observation of noise correlated by the Hawking effect in a water tank
Euvé, L -P; Parentani, R; Philbin, T G; Rousseaux, G
2015-01-01
We measure the power spectrum and two-point correlation function for the fluctuating free surface on the downstream side of a stationary flow above an obstacle with high Froude number $F \\approx 0.85$. 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 correlations clearly indicate a steady conversion of incident modes into pairs of modes of opposite energies. We then use a wave maker to measure the scattering coefficients responsible for this effect.
Finite width of the sonic event horizon and grey body Hawking radiation
Vinish, Y
2014-01-01
Finite width of the analog event horizon is determined by the nonlinearity length in the Kerr nonlinear optical system, which is discussed here, or by the healing length in Bose-Einstein condensates. The various eigen modes of fluctuations are found in the immediate vicinity of the event horizon and the scattering matrix due to the finite width horizon is calculated to within the leading order correction in the nonlinearity length. The Hawking radiation is found to be that of a grey body with the emissivity larger than one. A procedure of paraxial quantization of the fluctuation field is discussed and its connection to the conventional quantization of the electromagnetic field is demonstrated.
High-Altitude MMIC Sounding Radiometer - From the IIP to the Global Hawk
Brown, Shannon; Denning, Richard; Lambrigtsen, Bjorn; Lim, Boon; Tanabe, Jordan; Tanner, Alan; Kangaslahti, Pekka; Gaier, Todd
2011-01-01
The HAMSR instrument is a 25 channel cross-track microwave sounder developed by the Jet Propulsion Laboratory under the IIP-98 program. The instrument was recently upgraded under the NASA AITT program in 2008 to deploy on the Global Hawk UAV. The instrument now has state-of-the-art radiometric performance and the capability to process and display both brightness temperature imagery and derived products in real time. The improved performance of the instrument is demonstrated through retrievals of temperature and water vapor.
Martínez-Merino, Aldo; Ryan, Michael P
2016-01-01
Newtonian gravitation with some slight modifications, along with some highly simplified ideas from quantum field theory allow us to reproduce, at least at the level of back-of-the-envelope calculations, many results of black hole physics. We consider particle production by a black hole, the Newtonian equivalent of the Hawking temperature, and the Bekenstein entropy. Also, we are able to deduce Newtonian field equations from entropy. We finally study higher-order Newtonian theories under the same assumptions used for ordinary Newtonian theory. In a companion article we will look at entropic forces for various entropies and make contact with our analysis of higher-order Newtonian theories.
Extremal Black Holes in Supergravity and the Bekenstein-Hawking Entropy
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.
Microscopic derivation of the Bekenstein-Hawking entropy formula for non-extremal black holes
Sfetsos, K. [European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Skenderis, K. [Instituut voor Theoretische Fysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)
1998-04-27
We derive the Bekenstein-Hawking entropy formula for four- and five-dimensional non-supersymmetric black holes (which include the Schwarzchild ones) by counting microscopic states. This is achieved by first showing that these black holes are U-dual to the three-dimensional black hole of Banados-Teitelboim-Zanelli and then counting microscopic states of the latter following Carlip`s approach. Black holes higher than five dimensional are also considered. We discuss the connection of our approach to the D-brane picture. (orig.) 56 refs.
Microscopic derivation of the Bekenstein-Hawking entropy formula for non-extremal black holes
Sfetsos, K
1998-01-01
We derive the Bekenstein--Hawking entropy formula for four and five dimensional non-supersymmetric black holes (which include the Schwarzchild ones) by counting microscopic states. This is achieved by first showing that these black holes are U-dual to the three-dimensional black hole of Banados--Teitelboim--Zanelli and then counting microscopic states of the latter following Carlip's approach. Higher than five dimensional black holes are also considered. We discuss the connection of our approach to the D-brane picture.
Hawking radiation for non asymptotically flat dilatonic black holes using gravitational anomaly
Fabris, J C
2012-01-01
The $d$-dimensional scalar field action may be reduced, in the background geometry of a black hole, to a 2-dimensional effective action. In the near horizon region, it appears a gravitational anomaly: the energy-momentum tensor of the scalar field is not conserved anymore. This anomaly is removed by introducing a term related to the Hawking temperature of the black hole. Even if the temperature term introduced is not covariant, a gauge transformation may restore the covariance. We apply this method to compute the temperature of the black hole of the dilatonic non asymptotically flat black holes. We compare the results with those obtained through other methods.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
Pu, Jin; Han, Yan
2016-12-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
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.)
A novel technique for prevention of self-mutilation in three Harris' hawks (Parabuteo unicinctus).
Smith, Stephen P; Forbes, Neil A
2009-03-01
Feather destructive behavior is an ever-increasing problem in captive birds of prey and any associated self-mutilation can be challenging to manage. This clinical report describes a noninvasive, nonpainful, temporary beak modification technique used to prevent self-mutilation in 3 Harris' hawks (Parabuteo unicinctus), when other methods and husbandry modifications had failed. The technique was successful in all 3 birds, and no adverse effects were observed. Further investigations are required to further evaluate if this beak modification technique causes any psychologic or physical stress to the avian patient.
Robertson, Scott; Leonhardt, Ulf
2014-11-01
Hawking radiation has become experimentally testable thanks to the many analog systems which mimic the effects of the event horizon on wave propagation. These systems are typically dominated by dispersion and give rise to a numerically soluble and stable ordinary differential equation only if the rest-frame dispersion relation Ω^{2}(k) is a polynomial of relatively low degree. Here we present a new method for the calculation of wave scattering in a one-dimensional medium of arbitrary dispersion. It views the wave equation as an integral equation in Fourier space, which can be solved using standard and efficient numerical techniques.
Rosenfield, Robert N; Hardin, Madeline G; Bielefeldt, John; Keyel, Edward R
2017-01-01
Numerous studies have demonstrated earlier timing of spring migration and egg-laying in small passerines, but documentation of such responses to recent climate change in the life histories of higher trophic feeding birds such as raptors is relatively scarce. Raptors may be particularly susceptible to possible adverse effects of climate change due to their longer generation turnover times and lower reproductive capacity, which could lead to population declines because of an inability to match reproductive timing with optimal brood rearing conditions. Conversely adaptively favorable outcomes due to the influence of changing climate may occur. In general, birds that seasonally nest earlier typically have higher reproductive output compared to conspecifics that nest later in the season. Given the strong seasonal decline in reproductive output, and the heritability of nesting phenology, it is possible that nesting seasons would (adaptively) advance over time. Recent climate warming may release prior ecological constraints on birds that depend on food availability at the time of egg production, as do various raptors including Cooper's Hawks (Accipiter cooperii). Under this scenario, productivity, especially clutch size, might increase because it is likely that this reproductive demographic may be the most immediate response to the earlier seasonal presence of food resources. We demonstrated a statistically significant shift of about 4-5 days to an earlier timing of egg-hatching in spring across 36 years during 1980-2015 for a partially migratory population of Cooper's Hawks in Wisconsin, United States, which is consistent with a recent study that showed that Cooper's Hawks had advanced their timing of spring migration during 1979-2012. Both studies occurred in the Great Lakes region, an area that compared to global averages is experiencing earlier and increased warming particularly in the spring in Wisconsin. The nesting period did not lengthen. We suggest that the
Observation of Noise Correlated by the Hawking Effect in a Water Tank
Euvé, L.-P.; Michel, F.; Parentani, R.; Philbin, T. G.; Rousseaux, G.
2016-09-01
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 Fmax≈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.
Emerging Hawking-Like Radiation from Gravitational Bremsstrahlung Beyond the Planck Scale.
Ciafaloni, Marcello; Colferai, Dimitri; Veneziano, Gabriele
2015-10-23
We argue that, as a consequence of the graviton's spin-2, its bremsstrahlung in trans-Planckian-energy (E≫M(P)) gravitational scattering at small deflection angle can be nicely expressed in terms of helicity-transformation phases and their transfer within the scattering process. The resulting spectrum exhibits deeply sub-Planckian characteristic energies of order M(P)(2)/E≪M(P) (reminiscent of Hawking radiation), a suppressed fragmentation region, and a reduced rapidity plateau, in broad agreement with recent classical estimates.
Sakalli, I.
2016-10-01
Charged massive scalar field perturbations are studied in the gravitational, electromagnetic, dilaton, and axion fields of rotating linear dilaton black holes. In this geometry, we separate the covariant Klein-Gordon equation into radial and angular parts and obtain the exact solutions of both the equations in terms of the confluent Heun functions. Using the radial solution, we study the problems of resonant frequencies, entropy/area quantization, and greybody factor. We also analyze the behavior of the wave solutions near the event horizon of the rotating linear dilaton black hole and derive its Hawking temperature via the Damour-Ruffini-Sannan method.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
Pu, Jin; Han, Yan
2016-08-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Spin zero Hawking radiation for non-zero-angular momentum mode
Ngampitipan, Tritos [Department of Physics, Chulalongkorn University, Bangkok 10330 (Thailand); Bonserm, Petarpa [Department of Mathematics and Computer Science, Chulalongkorn University, Bangkok 10330 (Thailand); Visser, Matt [School of Mathematics, Statistics, and Operations Research, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand)
2015-05-15
Black hole greybody factors carry some quantum black hole information. Studying greybody factors may lead to understanding the quantum nature of black holes. However, solving for exact greybody factors in many black hole systems is impossible. One way to deal with this problem is to place some rigorous analytic bounds on the greybody factors. In this paper, we calculate rigorous bounds on the greybody factors for spin zero hawking radiation for non-zero-angular momentum mode from the Kerr-Newman black holes.
Hawking radiation screening and Penrose process shielding in the Kerr black hole
Caughey, Eamon Mc
2016-01-01
The radial motion of massive particles in the equatorial plane of the Kerr black hole is considered. Screening of the Hawking radiation and shielding of the Penrose process are examined (both insides and outside the ergosphere) and their effects on the evaporation of the black hole is studied. In particular, the locus and width of a classically forbidden region and their dependence on the particle's angular momentum and energy is analysed. Tunneling of particles between the boundaries of this region is considered and the transmission coefficient is determined.
Probing Hawking and Unruh effects and quantum field theory in curved space by geometric invariants
Capolupo, Antonio
2013-01-01
The presence of noncyclic geometric invariant is revealed in all the phenomena where particle generation from vacuum or vacuum condensates appear. Aharonov--Anandan invariants then can help to study such systems and can represent a new tool to be used in order to provide laboratory evidence of phenomena particulary hard to be detected, such as Hawking and Unruh effects and some features of quantum field theory in curved space simulated by some graphene morphologies. It is finally suggested that a very precise quantum thermometer can be built by exploiting geometric invariants properties.
Mechanism of stimulated Hawking radiation in a laboratory Bose-Einstein condensate
Wang, Yi-Hsieh; Edwards, Mark; Clark, Charles W
2016-01-01
We model a sonic black hole analog in a quasi one-dimensional Bose-Einstein condensate, using a Gross-Pitaevskii equation matching the configuration of a recent experiment by Steinhauer. The model agrees well with the experimental observations, with no adjustable parameters, demonstrating their hydrodynamic nature. With enhanced but experimentally feasible parameters we establish by spectral analysis that a growing bow wave is generated at the inner (white hole) horizon, stimulating the emission of Hawking radiation. The black hole laser effect plays no role.
Hawking radiation for non-asymptotically flat dilatonic black holes using gravitational anomaly
Fabris, J.C. [Universidade Federal do Espirito Santo, Departamento de Fisica, Vitoria, Espirito Santo (Brazil); Marques, G.T. [Universidade Federal Rural da Amazonia-Brazil, ICIBE-LASIC, Belem, Para (Brazil)
2012-12-15
The d-dimensional scalar field action may be reduced, in the background geometry of a black hole, to a two-dimensional effective action. In the near-horizon region, it appears a gravitational anomaly: the energy-momentum tensor of the scalar field is not conserved anymore. This anomaly is removed by introducing a term related to the Hawking temperature of the black hole. Even if the temperature term introduced is not covariant, a gauge transformation may restore the covariance. We apply this method to compute the temperature of the dilatonic non-asymptotically flat black holes. We compare the results with those obtained through other methods. (orig.)
Science-Grade Imaging Data for HAWK-I, VIMOS, and VIRCAM: The ESO-UK Pipeline Collaboration
Neeser, M.; Lewis, J.; Madsen, G.; Yoldas, A.; Irwin, M.; Gabasch, A.; Coccato, L.; García-Dabó, C. E.; Romaniello, M.; Freudling, W.; Ballester, P.
2016-12-01
A new chapter for ESO science-grade data has begun with the implementa-tion of three new pipelines developed for the HAWK-I, VIMOS and VIRCAM instruments. The HAWK-I and VIMOS image archives at ESO have been completely reprocessed using these new pipelines, and these data are now publicly available. This article introduces the work done to bring these pipelines to the level of science-grade, their use in reprocessing ESO archival data, and their dissemination into ESO science operations and to the ESO community.
CHEN Shi-Wu; LIU Xiong-Wei; LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Hawking radiation from cosmological horizon and event horizon of the Reissner-Nordstrom de Sitter black hole with a global monopole is studied via a new method that was propounded by Robinson and Wilzek and elaborated by Banerjee and Kulkarni. The results show that the gauge current and energy-momentum tensor fluxes, which required keeping gauge covariance and general coordinate invaxiance at the quantum level in the effective field theory, axe exactly equivalent to those of Hawking radiation from the event horizon and the cosmological horizon, respectively.
The Hawking Temperature in the context of Dark Energy for Reissner-Nordstrom background
Gangopadhyay, Debashis
2014-01-01
Recently, it has been shown that the Hawking temperature is modified in the presence of dark energy \\cite{dg}. This was shown for an emergent gravity metric having $k-$essence scalar fields $\\phi$ with a Born-Infeld type lagrangian and with the gravitational metric as Schwarzschild. Here the gravitational metric is taken to be Reissner-Nordstrom (R-N) and the we consider the axisymmetric case $\\theta=0$. The corresponding Hawking temperatures of the two horizons are found to be T_+ = {\\hbar c^3 (1-\\dot\\phi_2^2)^2 \\over {2\\pi k_B}} {\\sqrt{G^2 M^2 - Q^2 (1-\\dot\\phi_2^2)} \\over {(GM + \\sqrt{G^2 M^2 - Q^2 (1-\\dot\\phi_2^2)})^2}}$ and $T_- = -{\\hbar c^3 (1-\\dot\\phi_2^2)^2 \\over {2\\pi k_B}} {\\sqrt{G^2 M^2 - Q^2 (1-\\dot\\phi_2^2)} \\over {(GM - \\sqrt{G^2 M^2-Q^2 (1-\\dot\\phi_2^2)})^2}}$ Here $\\dot\\phi_2^2$ is the kinetic energy of the $k-$essence field $\\phi$ and $k_{\\mathrm B}$ is the Boltzmann constant. In the axisymmetric scenario, the scalar field $\\phi(r,t)=\\phi_{1}(r)+\\phi_{2}(t)$ also satisfies the emergent gravi...
Barbado, Luis C
2015-01-01
We study the perception of the radiation phenomena of Hawking radiation and Unruh effect by using two main tools: the Unruh-DeWitt detectors and the effective temperature function (ETF), this last tool based on Bogoliubov transformations. Using the Unruh-DeWitt detectors we find an adiabatic expansion of the detection properties along linear trajectories with slowly varying acceleration in Minkowski, which allows us to calculate the spectrum detected, finding the thermal spectrum as the zeroth order contribution. Using the ETF we study the perception of Hawking radiation by observers following radial trajectories outside a Schwarzschild black hole. One of the most important results is that, in general, free-falling observers crossing the event horizon do detect some radiation, even when the field is in the Unruh vacuum state, due to a Doppler blue-shift that diverges at the horizon. We give a general expression for the ETF, which has a clear interpretation in terms of well-known physical phenomena. We discuss...
Ratio of critical quantities related to Hawking temperature–entanglement entropy criticality
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.
Power distribution in the hovering flight of the hawk moth Manduca sexta
Zhao Liang; Deng Xinyan, E-mail: xdeng@purdue.ed [School of Mechanical Engineering, Purdue University, 500 Allison Rd., Chaffee Hall, West Lafayette, IN 47907 (United States)
2009-12-15
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
Hawking Radiation of a Quantum Black Hole in an Inflationary Universe
Huang, W H
1992-01-01
The quantum stress-energy tensor of a massless scalar field propagating in the two-dimensional Vaidya-de Sitter metric, which describes a classical model spacetime for a dynamical evaporating black hole in an inflationary universe, is analyzed. We present a possible way to obtain the Hawking radiation terms for the model with arbitrary functions of mass. It is used to see how the expansion of universe will affect the dynamical process of black hole evaporation. The results show that the cosmological inflation has an inclination to depress the black hole evaporation. However, if the cosmological constant is sufficiently large then the back-reaction effect has the inclination to increase the black hole evaporation. We also present a simple method to show that it will always produce a divergent flux of outgoing radiation along the Cauchy horizon where the curvature is a finite value. This means that the Hawking radiation will be very large in there and shall modify the classical spacetime drastically. Therefore ...
Pre-Hawking radiation may allow for reconstruction of the mass distribution of the collapsing object
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
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.
Hawking Radiation as a Possible Probe for the Interior Structure of Regular Black Holes
Deng, Yanbin; Cleaver, Gerald
2017-03-01
The notion of black hole singularity and the proof of the singularity theorem were considered great successes in classical general relativity whereas they meanwhile brought with deep puzzles. Conceptual challenges were set up by the intractability of the singularity. The existence of black hole horizons which cover up the black hole interior including the singularity from outside observers, builds an information curtain, further hindering physicists from understanding the nature of the singularity and the interior structure of black holes. The regular black hole is a concept produced out of multiple attempts of establishing a tractable and understandable interior structure for black holes as well as avoiding the singularity behind the black hole horizon. The practicality of the new constructions of black holes would be considered more reliable if there can be found some connection between the interior of regular black holes and some far-reaching signals released from the black hole. After studying the Hawking radiation by fermion tunnelling from one type of regular black hole, structure dependent results were obtained. The result being structure dependent hints the prospects of employing the Hawking radiation as a method to probe into the structure of black holes.
Li, Jin [Chongqing University, Department of Physics, Chongqing (China); Lin, Kai [Universidade de Sao Paulo, Instituto de Fisica, CP 66318, Sao Paulo (Brazil); Yang, Nan [Huazhong University of Science and Technology, Department of Physics, Wuhan (China)
2015-03-01
Based on a regular exact black hole (BH) from nonlinear electrodynamics (NLED) coupled to general relativity, we investigate the stability of such BH through the Quasinormal Modes (QNMs) of electromagnetic (EM) field perturbations and its thermodynamics through Hawking radiation. In perturbation theory, we can deduce the effective potential from a nonlinear EM field. The comparison of the potential function between regular and RN BHs could predict similar QNMs. The QNM frequencies tell us the effect of the magnetic charge q, the overtone n, and the angular momentum number l on the dynamic evolution of NLED EM field. Furthermore we also discuss the cases of near-extreme conditions of such a magnetically charged regular BH. The corresponding QNM spectrum illuminates some special properties in the near-extreme cases. For the thermodynamics, we employ the Hamilton-Jacobi method to calculate the near-horizon Hawking temperature of the regular BH and reveal the relationship between the classical parameters of the black hole and its quantum effects. (orig.)
Mechanism of stimulated Hawking radiation in a laboratory Bose-Einstein condensate
Jacobson, Ted; Wang, Yi-Hsieh; Edwards, Mark; Clark, Charles W.
2017-01-01
Analog black/white hole pairs have been achieved in recent experiment by J. Steinhauer, using an elongated Bose-Einstein condensate. He reported observations of self-amplifying Hawking radiation, via a lasing mechanism operating between the black and white hole horizons. Through the simulations using the 1D Gross-Pitaevskii equation, we find that the experimental observations should be attributed not to the black hole laser effect, but rather to a growing zero-frequency bow wave, generated at the white-hole horizon. The relative motion of the black and white hole horizons produces a Doppler shift of the bow wave at the black hole, where it stimulates the emission of monochromatic Hawking radiation. This mechanism is confirmed using temporal and spatial windowed Fourier spectra of the condensate. We also find that shot-to-shot atom number variations, of the type normally realized in ultracold-atom experiments, and quantum fluctuations of condensates, as computed in the Bogoliubov-De Gennes approximation, give density-density correlations consistent with those reported in the experiments. In particular, atom number variations can produce a spurious correlation signal.
A Red-Tailed Hawk perches on a stump at KSC.
2000-01-01
This red-tailed hawk on the roadside at Kennedy Space Center appears to be eyeing the photographer. The red-tailed hawk has a stocky build and broad, rounded wings. Its wide range covers Alaska and Nova Scotia south to Panama. It can frequently be seen perched in a tree at the edge of a meadow, watching for movement in the grass below. It feeds mainly on small rodents. The Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects. Kennedy Space Center shares a boundary with the Merritt Island National Wildlife Refuge, encompassing 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.
Maxwell's equal area law and the Hawking-Page phase transition
Spallucci, Euro
2013-01-01
In this paper we study the phases of a Schwarzschild black hole in the Anti deSitter background geometry. Exploiting fluid/gravity duality we construct the Maxwell equal area isotherm T=T* in the temperature-entropy plane, in order to eliminate negative heat capacity black hole configurations. The construction we present here is reminiscent of the isobar cut in the pressure-volume plane which eliminates un-physical part of the Van der Walls curves below the critical temperature. Our construction also modifies the Hawking-Page phase transition. Stable black holes are formed at the temperature T > T*, while pure radiation persists for T< T*. T* turns out to be below the standard Hawking-Page temperature and there are no unstable black holes as in the usual scenario. Also, we show that in order to reproduce the correct black hole entropy S=A/4, one has to write a black hole equation of state, i.e. P=P(V), in terms of the geometrical volume V=4\\pi r^3/3.