Microstructural evaluation of oxide layers in CaO-added Mg alloys
International Nuclear Information System (INIS)
Highlights: • Oxidation layer thickness of CaO added AM60 increases with increasing amounts of CaO. • Effect of CaO is that the columnar grains on AM60 grow along the [1 0 0]MgO. • A initial oxidation layer thickness and ignition temperature is closely connected. • The columnar oxide layer formed due to Ca, which dissolved from CaO. - Abstract: A transmission electron microscopy analysis was conducted on the oxide layers of Mg–5.5Al–0.25Mn (AM60) alloys with different levels of CaO content formed in a thermogravimetric analyzer (TGA) system at 450 °C for 7 h. It was found that the oxide layer in AM60 + CaO grew as a columnar structure and, resultantly, that the oxide layers had different thicknesses with different levels of CaO content. The columnar oxide grains that were formed on the Mg + CaO alloy grew on the [1 0 0]MgO, resulting in a more compact and thicker initial oxide layer compared to the normal oxide layer. The columnar growth of the oxide layer in AM60 + CaO formed due to the Ca, which dissolved from CaO
Gas Metal Arc Welding Using Novel CaO-Added Mg Alloy Filler Wire
Directory of Open Access Journals (Sweden)
Minjung Kang
2016-07-01
Full Text Available Novel “ECO Mg” alloys, i.e., CaO-added Mg alloys, which exhibit oxidation resistance during melting and casting processes, even without the use of beryllium or toxic protection gases such as SF6, have recently been introduced. Research on ECO Mg alloys is still continuing, and their application as welding filler metals was investigated in this study. Mechanical and metallurgical aspects of the weldments were analysed after welding, and welding behaviours such as fume generation and droplet transfer were observed during welding. The tensile strength of welds was slightly increased by adding CaO to the filler metal, which resulted from the decreased grain size in the weld metal. When welding Mg alloys, fumes have been unavoidable so far because of the low boiling temperature of Mg. Fume reduction was successfully demonstrated with a wire composed of the novel ECO Mg filler. In addition, stable droplet transfer was observed and spatter suppression could be expected by using CaO-added Mg filler wire.
Solid solution formation and microstructure of UO2 added with Nb and Ca
International Nuclear Information System (INIS)
Preparation of UO2 fuels added with Nb and Ca has been done by mixing UO2 with Nb2O5 and CaUO4 oxides respectively and heating them at 1390degC in stream of helium. Characterization has been then carried out with aid of X-ray diffraction analysis and metallography. The results can be summarized as follows. Nb could dissolve and form solid solution in UO2 with y up to 0.01, where y = Nb/(Ub+U) atomic ratio. The effect of Ca on the change of lattice parameter of the UO2 could be explained well using the simple ionic model, and according to this model, Ca occupies uranium sublattice of the UO2 (substitutional mechanism). Observation of the microstructure of the fuels showed that Nb created large grains and pores. The pores enlarged whether a liquid second phase was present or not. However, the grains did not enlarge and tended to be spherical when the liquid second phase was present. The structure of the liquid second phase could not be determined, but it had a melting point of 1328degC as confirmed by DTA. The evaluation also showed that Ca created small grains and pores. The difference in the grain and pore structure between (Nb,U)O2+x and (Ca,U)O2+x fuels was considered to be strongly due to the different lattice defect created by Nb and Ca, where Nb created a uranium vacancy which is considered to enhance the grain and pore growth and Ca created an oxygen vacancy which is considered to be less effective to enhance grain and pore growth. (author)
Padoł, Anna Maria; Draget, Kurt Ingar; Stokke, Bjørn Torger
2016-08-20
The effect of adding shorter alginate fragments highly enriched in α-l-guluronic acid (oligoG) on the Young's modulus of the Ca-induced alginate hydrogels were determined using nanoindentation. Ca-alginate gels using two low and one high molecular weight alginate, with increasing amount of added oligoG, were prepared at constant 20mM total Ca(2+) by in situ release of the cation. Differences in the effect on the mechanical properties of increasing amount of oligoG to the various alginate samples were attributed to their different capability to support network connectivity by junction zone formation. Upon decreasing the fractional Ca-saturation of all the α-l-guluronic acid residues (G) present, Fsat, by increasing the oligoG concentration, the lower molecular weight alginates displayed the largest reduction in Young's modulus. This was suggested to be due to the few sequences of α-l-guluronic acid residues making up potential zones engaging in network connectivity of this alginate. Similar trends were observed for a low molecular weight alginate with larger fraction of G. The higher molecular weight sample displayed less reduction of Young's modulus associated with increasing concentration of oligoG. The consequences of reduction in effective, mean junction zone functionality and associated increase in sol fraction with added oligoG on the elastic properties thus depend on the chain length of the alginates. These finding suggest that effects of added oligoG on Ca-induced alginate gelation should connect the effect on junction zone formation to those mediating network connectivity. PMID:27178929
Lindquist, Ole
1994-01-01
Thesis also available on the Fishernet Project's website: http://fishernet.is/en/whale-a-seal-hunting By way of introduction the thesis considers Norse whaling history, in general, concepts like 'whaling tradition', 'whaling culture', and describes the approach to the divers studies of cetaceans in Norse peasant fisherman economy and culture and of Norse whaling techniques, ca 900-1900 AD. It is argued that the Icelandic littoral and in...
Cabaleri, Nora G.; Benavente, Cecilia A.
2013-02-01
The Las Chacritas Member is the lower part of the Cañadón Asfalto Formation (Jurassic). The unit is a completely continental limestone succession with volcanic contributions that were deposited during the development of the Cañadón Asfalto Rift Basin (Chubut province, Patagonia, Argentina). A detailed sedimentological analysis was performed in the Fossati depocenter to determine the paleoenvironments that developed in the context of this rift. The Las Chacritas Member represents a carbonate paleolake system with ramp-shaped margins associated with wetlands that were eventually affected by subaerial exposure and pedogenesis. This process is represented by three main subenvironments: a) a lacustrine setting sensu stricto (lacustrine limestone facies association), represented by Mudstones/Wackestones containing porifera spicules (F1), Intraclastic packstones (F6) and Tabular stromatolites (F10) in which deposition and diagenesis were entirely subaqueous; b) a palustrine setting (palustrine limestone facies association) containing Microbial Mudstones (F2), Intraclastic sandy packstone with ostracode remains (F3), Oncolitic packstone (F5), Brecciated limestone (F7) and Nodular-Mottled limestone (F8) representing shallow marginal areas affected by groundwater fluctuations and minor subaerial exposure; and c) a pedogenic paleoenvironment (pedogenic limestone facies association) including Intraclastic limestone (F4) and Packstones containing Microcodium (F9) facies displaying the major features of subaerial exposure, pedogenic diagenesis and the development of paleosols. The fluvial-palustrine-lacustrine succession shows a general shallow upward trend in which contraction-expansion cycles are represented (delimited by exposure and surface erosion). The variations in the successive formations reflect the responses to fluctuations in a combination of two major controls, the tectonic and local climatic variables. The predominance of the palustrine facies associations was
Hereford, R.
2002-01-01
Valley-fill alluvium deposited from ca. A.D. 1400 to 1880 is widespread in tributaries of the Paria River and is largely coincident with the Little Ice Age epoch of global climate variability. Previous work showed that alluvium of this age is a mappable stratigraphic unit in many of the larger alluvial valleys of the southern Colorado Plateau. The alluvium is bounded by two disconformities resulting from prehistoric and historic arroyo cutting at ca. A.D. 1200-1400 and 1860-1910, respectively. The fill forms a terrace in the axial valleys of major through-flowing streams. This terrace and underlying deposits are continuous and interfinger with sediment in numerous small tributary valleys that head at the base of hillslopes of sparsely vegetated, weakly consolidated bedrock, suggesting that eroded bedrock was an important source of alluvium along with in-channel and other sources. Paleoclimatic and high-resolution paleoflood studies indicate that valley-fill alluviation occured during a long-term decrease in the frequency of large, destructive floods. Aggradation of the valleys ended about A.D. 1880, if not two decades earlier, with the beginning of historic arroyo cutting. This shift from deposition to valley entrenchment near the close of the Little Ice Age generally coincided with the beginning of an episode of the largest floods in the preceding 400-500 yr, which was probably caused by an increased recurrence and intensity of flood-producing El Nin??o events beginning at ca. A.D. 1870.
The period AD 900 to 1300, internationally referred to as the Medieval Warm Period, is a critical time for the archaeological record of the Southwestern USA. During the Medieval Warm Period both alluvial and eolian sedimentation increased, but not to the magnitude of the middle Holocene (the Altithe...
Holwerda, Femke M.; Pol, Diego; Rauhut, Oliver W. M.
2015-01-01
The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic–early Middle Jurassic) in Central Patagonia (Argentina), which may help to shed light on the early evolution of eusauropods. These eusauropod remains include teeth associated with cranial and mandibular material as well as isolated teeth found at different localities. In this study, an assemblage of sauropod teeth from the Cañadón Asfalto Formation found in four different localities in the area of Cerro Condor (Chubut, Argentina) is used as a mean of assessing sauropod species diversity at these sites. By using dental enamel wrinkling, primarily based on the shape and orientation of grooves and crests of this wrinkling, we define and describe three different morphotypes. With the exception of one taxon, for which no cranial material is currently known, these morphotypes match the local eusauropod diversity as assessed based on postcranial material. Morphotype I is tentatively assigned to Patagosaurus, whereas morphotypes II and III correspond to new taxa, which are also distinguished by associated postcranial material. This study thus shows that enamel wrinkling can be used as a tool in assessing sauropod diversity. PMID:25692466
DENSIDAD Y DISTRIBUCIÓN SOBRE CSMA/CA EN REDES IEEE 802.11G EN MODO AD HOC
José Domínguez
2009-01-01
El propósito principal de la presente investigación, fue determinar la influencia de la densidad y distribución de hosts sobre el control de acceso al medio en redes IEEE 802.11g, tomando como variables fundamentales la densidad y distribución de los mismos y el protocolo CSMA/CA para el acceso al medio de transmisión. La investigación fue de tipo explicativa, con un diseño experimental puro. La misma se basó en los postulados teóricos de Bates (2003), Comer (2000), León García (2001), Sta...
Yuan, W. X.; Hark, S. K.
2010-03-01
CaCu3Ti4O12 (CCTO), an unusual perovskite-like ceramic, is known for its extraordinarily high (˜10^4) and relatively frequency independent dielectric constant. It has drawn a lot of attention recently because of its potential applications in microelectronics and microwave devices. In this investigation, HfO2 powder was added to a pre-reacted CCTO powder, which was synthesized by a conventional solid-state reaction, at different concentrations from 1 to 70 wt% and the mixture was sintered into disc-shaped ceramic samples. The effects of adding HfO2 on the microstructure and dielectric properties of CCTO ceramics were investigated. In general, we found that the dielectric constant tends to increase with HfO2 addition up to 8 wt% and then decrease with further addition. Moreover, the dielectric loss was also influenced by the addition of HfO2, and a low loss tangent of ˜0.035 was obtained. The ac conductivity, impedance, complex dielectric permittivity and electric modulus graphs were used to analyze the data. These observations were explained on the basis of the internal-barrier-layer capacitor model with Maxwell-Wagner relaxations.
Norse Greenland dietary economy ca. AD 980-ca. AD 1450
DEFF Research Database (Denmark)
Arneborg, J.; Lynnerup, Niels; Heinemeier, Jan;
2012-01-01
An initial study of the C values for human bone collagen of 27 Norse Greenlanders in the late 1990s suggested a change in the Norse diet from predominantly terrestrial to predominantly marine food. This shift may well indicate a change in diet; the question left open by the limited initial isotop...
Directory of Open Access Journals (Sweden)
Nora Cabaleri
2010-05-01
Full Text Available El depocentro Cerro Cóndor representa la secuencia estratigráfica del Jurásico continental más completa de la cuenca de Cañadón Asfalto y de Sudamérica austral. Se sitúa en la Patagonia extraandina, en ambas márgenes del río Chubut medio. La sedimentación en esta cuenca pull apart, acompañada por efusiones de basalto olivínico, comenzó en el Jurásico Medio temprano. Predominan en la Formación Cañadón Asfalto los depósitos lacustres caracterizados por asociaciones de facies carbonáticas y siliciclásticas intercaladas con rocas lávicas en la base y depósitos piroclásticos hacia el techo de la unidad. Se describe el desarrollo de facies a lo largo de un corte norte-sur que abarca las secciones de estancia El Torito y de los cañadones Los Loros, Las Chacritas, Carrizal, Asfalto y Lahuincó. Las facies/microfacies carbonáticas están representadas por mudstones, wackestones,packstones, grainstones y calizas microbialíticas características de ambientes litorales, marginales y palustres. En la Formación Cañadón Asfalto se distinguen un miembro inferior (Las Chacritas, constituido por calizas, lutitas, areniscas y conglomerados, intercalados con basaltos olivínicos y por otro superior (Puesto Almada compuesto por tobas, tufitas, lutitas y areniscas. El primero es portador de una asociación palinológica de edad bajociano-bathoniana y el segundo de dinosaurios de edad tithoniana. Se describen detalladamente e ilustran las secciones estratigráficas de ambos miembros de la formación en sus localidades tipo, cañadón Las Chacritas y estancia el Torito y se reconstruyen los paleoambientes del depocentro desde el Aaleniano al Tithoniano. La edad del miembro Puesto Almada en su localidad tipo se obtuvo mediante una datación radimétrica (K/Ar de biotitas provenientes de una delgada capa de toba volcánica (147,1 ± 3,3 Ma, Tithoniano proveniente de la parte superior de la unidad.The Cerro Cóndor depocenter represents the
Cabaleri, Nora G.; Benavente, Cecilia A.; Monferran, Mateo D.; Narváez, Paula L.; Volkheimer, Wolfgang; Gallego, Oscar F.; Do Campo, Margarita D.
2013-10-01
Six facies associations are described for the Puesto Almada Member at the Cerro Bandera locality (Fossati sub-basin). They correspond to lacustrine, palustrine, and pedogenic deposits (limestones); and subordinated alluvial fan, fluvial, aeolian, and pyroclastic deposits. The lacustrine-palustrine depositional setting consisted of carbonate alkaline shallow lakes surrounded by flooded areas in a low-lying topography. The facies associations constitute four shallowing upward successions defined by local exposure surfaces: 1) a Lacustrine-Palustrine-pedogenic facies association with a 'conchostracan'-ostracod association; 2) a Palustrine facies association representing a wetland subenvironment, and yielding 'conchostracans', body remains of insects, fish scales, ichnofossils, and palynomorphs (cheirolepidiacean species and ferns growing around water bodies, and other gymnosperms in more elevated areas); 3) an Alluvial fan facies association indicating the source of sediment supply; and 4) a Lacustrine facies association representing a second wetland episode, and yielding 'conchostracans', insect ichnofossils, and a palynoflora mainly consisting of planktonic green algae associated with hygrophile elements. The invertebrate fossil assemblage found contains the first record of fossil insect bodies (Insecta-Hemiptera and Coleoptera) for the Cañadón Asfalto Formation. The succession reflects a mainly climatic control over sedimentation. The sedimentary features of the Puesto Almada Member are in accordance with an arid climatic scenario across the Upper Jurassic, and they reflect a strong seasonality with periods of higher humidity represented by wetlands and lacustrine sediments.
Jurassic tetrapods and flora of Cañadón Asfalto Formation in Cerro Cóndor area, Chubut Province
Directory of Open Access Journals (Sweden)
Ignacio H. Escapa
2008-12-01
Full Text Available The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic found in Cerro Cóndor area (Chubut Province is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been interpreted as representatives of a new species of Notobatrachus, considered one of the most basal members of the anuran lineage. Similarly, turtle remains have been recently recognized as a new species of basal turtle, bringing valuable information about the early evolution of this group. The dinosaur remains are largely dominated by saurischian taxa, represented by basal forms of Eusauropoda and Tetanurae. In addition, three different mammalian species have been identified and considered as early representatives of an endemic Gondwanan mammalian fauna. The fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.
Fiske, R.S.; Rose, T.R.; Swanson, D.A.; Champion, D.E.; McGeehin, J.P.
2009-01-01
K??lauea may be one of the world's most intensively monitored volcanoes, but its eruptive history over the past several thousand years remains rather poorly known. Our study has revealed the vestiges of thin basaltic tephra deposits, overlooked by previous workers, that originally blanketed wide, near-summit areas and extended more than 17 km to the south coast of Hawai'i. These deposits, correlative with parts of tephra units at the summit and at sites farther north and northwest, show that K??lauea, commonly regarded as a gentle volcano, was the site of energetic pyroclastic eruptions and indicate the volcano is significantly more hazardous than previously realized. Seventeen new calibrated accelerator mass spectrometry (AMS) radiocarbon ages suggest these deposits, here named the Kulanaokuaiki Tephra, were emplaced ca. A.D. 400-1000, a time of no previously known pyroclastic activity at the volcano. Tephra correlations are based chiefly on a marker unit that contains unusually high values of TiO2 and K2O and on paleomagnetic signatures of associated lava flows, which show that the Kulanaokuaiki deposits are the time-stratigraphic equivalent of the upper part of a newly exhumed section of the Uw??kahuna Ash in the volcano's northwest caldera wall. This section, thought to have been permanently buried by rockfalls in 1983, is thicker and more complete than the previously accepted type Uw??kahuna at the base of the caldera wall. Collectively, these findings justify the elevation of the Uw??kahuna Ash to formation status; the newly recognized Kulanaokuaiki Tephra to the south, the chief focus of this study, is defined as a member of the Uw??kahuna Ash. The Kulanaokuaiki Tephra is the product of energetic pyroclastic falls; no surge- or pyroclastic-flow deposits were identified with certainty, despite recent interpretations that Uw??kahuna surges extended 10-20 km from K??lauea's summit. ?? 2009 Geological Society of America.
Densidad y distribución sobre CSMA/CA en redes IEEE 802.11g en modo AD HOC
Directory of Open Access Journals (Sweden)
José Domínguez
2010-09-01
Full Text Available El propósito principal de la presente investigación, fue determinar la influencia de la densidad y distribución de hosts sobre el control de acceso al medio en redes IEEE 802.11g, tomando como variables fundamentales la densidad y distribución de los mismos y el protocolo CSMA/CA para el acceso al medio de transmisión. La investigación fue de tipo explicativa, con un diseño experimental puro. La misma se basó en los postulados teóricos de Bates (2003, Comer (2000, León García (2001, Stallings (2005, Tanenbaum (2003, entre otros. El procedimiento a utilizar fue diseñado por el investigador y consistió de cuatro (04 fases: Enfoque teórico, experimentación, Recolección y análisis de los datos y elaboración de conclusiones y recomendaciones. La cantidad de hosts a utilizar en la red se ubicó en seis 06 equipos portátiles con especificaciones técnica similares. Para la recolección de la información se diseño un (1 instrumento, tipo formato de datos, en el cual se registraron diez (10 parámetros diferentes para evaluar el desempeño de la red en diversos escenarios. Seguidamente se tabularon los datos en cuadros, para proceder al análisis cuantitativo de los mismos. Se concluye que la densidad y distribución de los hosts en redes IEEE 802.11g afectan el acceso al medio de transmisión.Palabras clave: Densidad, distribución, red, ad hoc, control de acceso al medio.
Directory of Open Access Journals (Sweden)
Nora Cabaleri
2010-05-01
Full Text Available El depocentro Cerro Cóndor representa la secuencia estratigráfica del Jurásico continental más completa de la cuenca de Cañadón Asfalto y de Sudamérica austral. Se sitúa en la Patagonia extraandina, en ambas márgenes del río Chubut medio. La sedimentación en esta cuenca pull apart, acompañada por efusiones de basalto olivínico, comenzó en el Jurásico Medio temprano. Predominan en la Formación Cañadón Asfalto los depósitos lacustres caracterizados por asociaciones de facies carbonáticas y siliciclásticas intercaladas con rocas lávicas en la base y depósitos piroclásticos hacia el techo de la unidad. Se describe el desarrollo de facies a lo largo de un corte norte-sur que abarca las secciones de estancia El Torito y de los cañadones Los Loros, Las Chacritas, Carrizal, Asfalto y Lahuincó. Las facies/microfacies carbonáticas están representadas por mudstones, wackestones,packstones, grainstones y calizas microbialíticas características de ambientes litorales, marginales y palustres. En la Formación Cañadón Asfalto se distinguen un miembro inferior (Las Chacritas, constituido por calizas, lutitas, areniscas y conglomerados, intercalados con basaltos olivínicos y por otro superior (Puesto Almada compuesto por tobas, tufitas, lutitas y areniscas. El primero es portador de una asociación palinológica de edad bajociano-bathoniana y el segundo de dinosaurios de edad tithoniana. Se describen detalladamente e ilustran las secciones estratigráficas de ambos miembros de la formación en sus localidades tipo, cañadón Las Chacritas y estancia el Torito y se reconstruyen los paleoambientes del depocentro desde el Aaleniano al Tithoniano. La edad del miembro Puesto Almada en su localidad tipo se obtuvo mediante una datación radimétrica (K/Ar de biotitas provenientes de una delgada capa de toba volcánica (147,1 ± 3,3 Ma, Tithoniano proveniente de la parte superior de la unidad.
Directory of Open Access Journals (Sweden)
Ignacio H. Escapa
2008-12-01
Full Text Available The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic found in Cerro Cóndor area (Chubut Province is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been interpreted as representatives of a new species of Notobatrachus, considered one of the most basal members of the anuran lineage. Similarly, turtle remains have been recently recognized as a new species of basal turtle, bringing valuable information about the early evolution of this group. The dinosaur remains are largely dominated by saurischian taxa, represented by basal forms of Eusauropoda and Tetanurae. In addition, three different mammalian species have been identified and considered as early representatives of an endemic Gondwanan mammalian fauna. The fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.Se resume brevemente el registro de plantas y tetrápodos fósiles de la Formación Cañadón Asfalto (Jurásico Medio a Superior en el área de Cerro Cóndor, provincia de Chubut. La flora está conformada por coníferas de las familias Araucariaceae y Cupressaceae sensu lato dominando la asociación, la cual se completa con helechos y equisetales en proporciones menores. La fauna de tetrápodos se compone por los clásicos dinosaurios descriptos en los 70`s, a los que se suman nuevos restos pertenecientes a este grupo, así como anfibios, tortugas y mamíferos coleccionados en la última década. Los restos de anfibios han sido interpretados como representantes de una nueva especie de Notobatrachus, considerado
Directory of Open Access Journals (Sweden)
Durán Barceló, Javier
2012-01-01
Full Text Available Aunque ya estaba catalogado desde 1745 y de nuevo en 1800, los modernos estudiosos no tuvieron noticia de la existencia de este manuscrito del siglo XV de Alfonso de Palencia hasta que Bartolomé José Gallardo lo describió. Gallardo describe el manuscrito Ad Alfonsum de Velasco in funebrem Abulensis praesulis cuando éste se encontraba a modo de préstamo en la Real Academia de la Historia, en Madrid, a mediados del siglo XIX. En aquella época la RAH procuraba la publicación de las obras de Alfonso de Palencia y seguramente a aquellos esfuerzos se debe que se conserve actualmente en la RAH una copia moderna de este manuscrito medieval, el cual fue devuelto a su propietaria. La primera edición del texto la hicieron en 1982 Brian Tate y Rafael Alemany Ferrer basándose para ello en la copia decimonónica. Pues, dado que Gallardo había dado una información confusa acerca de la localización del manuscrito medieval, los modernos editores no pudieron localizarlo. Este trabajo resuelve finalmente el problema de la localización del manuscrito original, conservado en la Universidad Complutense de Madrid. Gracias a este hallazgo mi edición del texto se basa directamente en el original medieval sobre el que intento dilucidar algunas lecturas difícilesAlthough it had been catalogued in 1745 and again in 1800, it was not until Bartolomé José Gallardo reported the existence of this 15th century manuscript of Alfonso de Palencia when scholars became aware of its existence. Gallardo described the manuscript Ad Alfonsum de Velasco in funebrem Abulensis praesulis when it was borrowed by the Royal Academy of History, in Madrid, in mid 19th century. At that time the Academy was involved in the edition of the works of Alfonso de Palencia and for this reason a hand written copy of the medieval manuscript remained in the Academy, while the original was returned to its owner. Based on this 19th century copy, Brian Tate and Rafael Alemany Ferrer published
Commendador, Amy S; Dudgeon, John V; Finney, Bruce P; Fuller, Benjamin T; Esh, Kelley S
2013-10-01
Ecological and environmental evidence suggests that Rapa Nui was among the most marginally habitable islands in Eastern Polynesia, with only a fraction of the biotic diversity found on archipelagos to the west, and capable of sustaining many fewer cultigens traditionally transported by Polynesian colonizers. However, archaeological evidence for human dietary adaptations under such restrictions is limited. Little is known about the particulars of the subsistence base and dietary changes on Rapa Nui that may be associated with a hypothesized late prehistoric decline in the quality and diversity of food sources. To better understand prehistoric Rapa Nui diet we examined stable carbon and nitrogen isotope compositions of human teeth along with archaeological faunal material thought to comprise the Rapa Nui food web. Our results indicate that contrary to previous zooarchaeological studies diet was predominantly terrestrial throughout the entire sequence of occupation, with reliance on rats, chickens and C3 plants. While a few individuals may have had access to higher trophic level marine resources, this is evident only later in time (generally post-AD 1600). A decline in (15)N through time was observed, and may be attributed to declines in available terrestrial proteins; however, presently we cannot rule out the effect of changing soil and plant baseline δ(15)N. Our results also suggest differential access to higher trophic level marine resources among contemporaneous populations, but more research is required to clarify this observation. PMID:23996514
Anabalon, Andres; Choque, David
2016-01-01
We construct exact hairy AdS soliton solutions in Einstein-dilaton gravity theory. We discuss the role of these solutions for the existence of first order phase transitions for planar hairy black holes within these theories.
In, Chi-Seung; Yeo, Dong-Hun; Shin, Hyo-Soon; Nahm, Sahn; Choi, Won-Youl
2015-04-01
In accordance with the trend for mobile terminals to be high intensity and to have thinner layers, low temperature co-fired ceramics (LTCC) materials with outstanding dielectric loss characteristics and diverse dielectric constants have been in demand, and the need for high-strength materials that can withstand external shocks has increased. Ca[(Li1/3Nb2/3)1- x Ti x ]O3- δ (CLNT) has a quality factor over 14,000 and τ f ≤ 10 when the dielectric constant is 41 ˜ 46, but its sintering temperature is high at 1150 °C. Therefore, it cannot be used as a LTCC component. This study aimed to lower the sintering temperature to 900 °C by adding a low-melting-point glass such as B2O3·SiO2·BaO and B2O3·SiO2·Al2O3. As the glass content in CLNT was increased from 10 wt% to 20 wt%, the density and the Q·f0 property decreased, and the dielectric constant rose. When B2O3·SiO2·BaO was added to CLNT at 15 wt%, the dielectric constant was found to be 27, the Q·f0 property to be 3470, and the τ f to be -18 ppm/°C. When B2O3·SiO2·Al2O3 was added to CLNT at 10 wt%, the dielectric constant was 20, the Q·f0 property was 3990, and the τ f was -15 ppm/°C. As such, in both cases, excellent dielectric properties were observed.
... Restaurant Deciphering the Menu Ordering Your Meal Eating Fast Food Dining Out Tips by Cuisine Physical Activity Fitness ... Learn more about reading food labels . Limit your consumption of foods with high amounts of added sugars, ...
Maldacena, Juan; Maoz, Liat
2004-01-01
We construct a few Euclidean supergravity solutions with multiple boundaries. We consider examples where the corresponding boundary field theory is well defined on each boundary. We point out that these configurations are puzzling from the AdS/CFT point of view. A proper understanding of the AdS/CFT dictionary for these cases might yield some information about the physics of closed universes.
Complexity Growth for AdS Black Holes
Cai, Rong-Gen; Wang, Shao-Jiang; Yang, Run-Qiu; Peng, Rong-Hui
2016-01-01
We further investigate the Complexity-Action (CA) duality conjecture for stationary anti de-Sitter (AdS) black holes and derive some exact results for the growth rate of action within Wheeler-DeWitt (WDW) patch at late time approximation, which is dual to the growth rate of quantum complexity of holographic state. Based on the results from the general $D$-dimensional Reissner-Nordstr\\"{o}m (RN)-AdS black hole, rotating/charged Ba\\~{n}ados-Teitelboim-Zanelli (BTZ) black hole, Kerr-AdS black hole and charged Gauss-Bonnet-AdS black hole, we present a new complexity bound but leave unchanged the conjecture that the stationary AdS black hole in Einstein gravity is the fastest computer in nature.
Powers, Shelley
2007-01-01
Ajax can bring many advantages to an existing web application without forcing you to redo the whole thing. This book explains how you can add Ajax to enhance, rather than replace, the way your application works. For instance, if you have a traditional web application based on submitting a form to update a table, you can enhance it by adding the capability to update the table with changes to the form fields, without actually having to submit the form. That's just one example.Adding Ajax is for those of you more interested in extending existing applications than in creating Rich Internet Applica
Electrodeposition of Ca Metal in CaCl2-CaO Molten Salt
Institute of Scientific and Technical Information of China (English)
GUO; Jun-kang; WANG; Chang-shui; CAO; Long-hao; OUYANG; Ying-gen
2013-01-01
To realize the continuouscalciothermic reduction in molten salts,the electrodeposition behavior of Ca metal in CaCl2-CaO molten salt was investigated by cylic voltammetry.The cyclic voltammograms at the scan rate of 100 mV/s are shown in Fig.1.As is shown,the electrodeposition potential of Ca deviated from-1.66 V to-0.97 V after CaO was added to molten CaCl2 and the decomposition of CaO
Verónica Isabel Williams; María Soledad Gheggi
2013-01-01
We present data on carbon and nitrogen isotopic composition of human bones from Tolombón (Calchaqui Valley, Salta) and Esquina de Huajra (Quebrada de Humahuaca, Jujuy) sites located in Northwest Argentina (NWA). Both are complex archaeological residential settlements ascribed to the Regional Development Period (ca. 900–1430 A.D.), the Inca Period (ca. 1430–1536 A.D.), and the Early Colonial Period (ca. 1536–1600 A.D.). Twelve samples of human bones were collected and analyzed, including remai...
Liu, Lijuan; Cui, Mingqi; Hu, Yongfeng; Zheng, Lei; Zhao, Yidong; Ma, Chenyan; Xi, Shibo; Yang, Dongliang; Guo, Zhiying; Wang, Jie
2012-01-01
This work is concerned with the Ca transformations during the pyrolysis of Ca(OH)2 or CaCO3-added coals. Ca K-edge X-ray absorption near edge structure (XANES) spectroscopy was applied to determine the forms of Ca in chars prepared from the pyrolysis of Ca-added coal. Results showed that Ca(OH)2 and CaSO4 existed in both the Ca(OH)2-added chars and the CaCO3-added chars, while CaS and CaO only existed in the chars prepared from the Ca(OH)2-added coal. Moreover, it was found that carboxyl Ca was formed during pyrolysis for either the Ca(OH)2-added coal or the CaCO3-added coals.
Online Ad Assignment with an Ad Exchange
Dvořák, Wolfgang; Henzinger, Monika
2016-01-01
Ad exchanges are becoming an increasingly popular way to sell advertisement slots on the internet. An ad exchange is basically a spot market for ad impressions. A publisher who has already signed contracts reserving advertisement impressions on his pages can choose between assigning a new ad impression for a new page view to a contracted advertiser or to sell it at an ad exchange. This leads to an online revenue maximization problem for the publisher. Given a new impression to sell decide whe...
Two AdS2 branes in the euclidean AdS3
International Nuclear Information System (INIS)
We compute the density of open strings stretching between AdS2 branes in the euclidean AdS3. This is done by solving the factorization constraint of a degenerate boundary field, and the result is checked by a Cardy-type computation. We mention applications to branes in the minkowskian AdS3 and its cigar coset. (author)
Two AdS2 branes in the Euclidean AdS3
Ribault, S
2003-01-01
We compute the density of open strings stretching between AdS2 branes in the Euclidean AdS3. This is done by solving the factorization constraint of a degenerate boundary field, and the result is checked by a Cardy-type computation. We mention applications to branes in the Minkowskian AdS3 and its cigar coset.
Energy Technology Data Exchange (ETDEWEB)
Tripathi, Rahul; Awana, V P S; Agarwal, S K; Kishan, H [National Physical Laboratory, Dr K S Krishnan Marg, New Delhi-110012 (India); Panwar, Neeraj [Department of Physics, Indian Institute of Technology, New Delhi-110016 (India); Bhalla, G L [Department of Physics and Astrophysics, University of Delhi, Delhi-1100007 (India); Habermier, H U, E-mail: awana@mail.nplindia.ernet.i [Max Planck Institut fur Festkoerperforschung, Heisenbergstrasse-70569, Stuttgart (Germany)
2009-09-07
In this paper we report an enhanced temperature coefficient of resistance (TCR) close to room temperature in La{sub 0.7}Ca{sub 0.3-x}Ba{sub x}MnO{sub 3} + Ag{sub y} (x = 0.10, 0.15 and 0 {<=} y {<=} 1.0) (LCBMO + Ag) composite manganites. The observed enhancement of TCR is attributed to the grain growth and opening of new conducting channels in the composites. Ag addition has also been found to enhance intragranular magnetoresistance. Intergranular MR, however, is seen to decrease with Ag addition. The enhanced TCR and MR at/near room temperature open up the possibility of the use of such materials as infrared bolometric and magnetic field sensors, respectively.
AdS solutions through transgression
International Nuclear Information System (INIS)
We present new classes of explicit supersymmetric AdS3 solutions of type IIB supergravity with non-vanishing five-form flux and AdS2 solutions of D=11 supergravity with electric four-form flux. The former are dual to two-dimensional SCFTs with (0,2) supersymmetry and the latter to supersymmetric quantum mechanics with two supercharges. We also investigate more general classes of AdS3 solutions of type IIB supergravity and AdS2 solutions of D=11 supergravity which in addition have non-vanishing three-form flux and magnetic four-form flux, respectively. The construction of these more general solutions makes essential use of the Chern-Simons or ''transgression'' terms in the Bianchi identity or the equation of motion of the field strengths in the supergravity theories. We construct infinite new classes of explicit examples and for some of the type IIB solutions determine the central charge of the dual SCFTs. The type IIB solutions with non-vanishing three-form flux that we construct include a two-torus, and after two T-dualities and an S-duality, we obtain new AdS3 solutions with only the NS fields being non-trivial. (orig.)
Costa, Miguel S; Oliveira, Miguel; Penedones, João; Santos, Jorge E
2015-01-01
We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global $AdS_{4}$ with conformal boundary $S^{2}\\times\\mathbb{R}_{t}$. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic $AdS$ behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an $AdS$ soliton that includes the full backreaction of the electric field on the $AdS$ geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both $AdS$ soliton and black hole phases. The corresponding phase diagram generalizes the Hawkin...
Indian Academy of Sciences (India)
S N Ekbote; G K Padam; M Sharma; N K Arora; B S Khurana; R C Goel; D K Suri; N Mehra; B K Das
2001-12-01
Bulk tube conductors of Bi1.84Pb0.4Sr2Ca2.2Cu3O10+ with addition of silver varying from 0 to 25 wt% (not reported earlier) were systematically studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical transport and a.c. susceptibility techniques. The tube conductors formed by cold isostatic pressing (CIP) of the powders obtained from spray drying method have been made successfully. It was found that Ag addition has not only affected the formation of the desired Bi-2223 phase and the microstructure of these large bulk tube samples thereby influencing on the critical current (c), it also reduces the contact resistance to minimize the cryogen losses. These variations have been found to be Ag content dependent. An optimized value of 10 wt% Ag has been found to produce the best quality tubes showing reproducible c value > 120 Amp at 77 K which is in general a requirement to energies of the cryogen free conventional/HTSC superconducting magnets below 20 K.
Elliot-Ripley, Matthew; Winyard, Thomas
2015-01-01
We study the baby Skyrme model in a pure AdS background without a mass term. The tail decays and scalings of massless radial solutions are demonstrated to take a similar form to those of the massive flat space model, with the AdS curvature playing a similar role to the flat space pion mass. We also numerically find minimal energy solutions for a range of higher topological charges and find that they form concentric ring-like solutions. Popcorn transitions (named in analogy with studies of toy...
Current status of AdS instability
CERN. Geneva
2016-01-01
arXiv:1403.6471 and thoroughly developed in arXiv:1407.6273. On the other hand the negative cosmological constant allows for the existence of stable, time-periodic, asymptotically AdS solutions of Einstein equations [arXiv:1303.3186].
Maldacena, Juan M.
2001-01-01
We propose a dual non-perturbative description for maximally extended Schwarzschild Anti-de-Sitter spacetimes. The description involves two copies of the conformal field theory associated to the AdS spacetime and an initial entangled state. In this context we also discuss a version of the information loss paradox and its resolution.
AdS braneworld with Backreaction
Bilić Neven; Tupper Gary
2013-01-01
We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.
AdS braneworld with Backreaction
Bilic, Neven
2014-01-01
We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.
Superradiant instability in AdS
Ganchev, Bogdan
2016-01-01
The phenomenon of superradiance in the context of asymptotically global AdS spacetimes is investigated with particular accent on its effect on the stability of the systems under consideration. To this end, the concept of an asymptotically AdS spacetime is explained, together with its implications on the boundary conditions at $\\mathcal{I}$, as well as the Newman-Penrose-Teukolsky formalism, whereby the Teukolsky master equation in a most general form for Kerr-AdS is given. Furthermore, work done in the cases of RN-AdS and Kerr-AdS is laid out in a concise manner, putting emphasis on the important steps taken in determining the endpoint of the superradiant instability in the two configurations. For the former this turns out to be a black hole with reduced charge and a static charged scalar condensate around it, whereas for the latter two of the more probable outcomes are presented, both of which imply a violation of one of the cosmic censorships.
Instability corners in AdS space
Dimitrakopoulos, Fotios V; Lippert, Matthew; Yang, I-Sheng
2014-01-01
We investigate whether arbitrarily small perturbations in global AdS space are generically unstable and collapse into black holes on the time scale set by gravitational interactions. We argue that current evidence, combined with our analysis, strongly suggests that a set of nonzero measure in the space of initial conditions does not collapse on this time scale. On the other hand, existing results do not provide an equally strong indication whether the unstable solutions also form a set of nonzero measure. We perform an analysis in position space to address this puzzle, and our formalism allows us to directly address the vanishing-amplitude limit. We show that gravitational self-interaction leads to tidal deformations which are equally likely to focus or defocus energy, and we sketch the phase diagram accordingly. We also clarify the connection between gravitational evolution in global AdS and holographic thermalization.
Elliot-Ripley, Matthew
2015-01-01
We study the baby Skyrme model in a pure AdS background without a mass term. The tail decays and scalings of massless radial solutions are demonstrated to take a similar form to those of the massive flat space model, with the AdS curvature playing a similar role to the flat space pion mass. We also numerically find minimal energy solutions for a range of higher topological charges and find that they form concentric ring-like solutions. Popcorn transitions (named in analogy with studies of toy models of holographic QCD) from an n layer to an n+1-layer configuration are observed at topological charges 9 and 27 and further popcorn transitions for higher charges are predicted. Finally, a point-particle approximation for the model is derived and used to successfully predict the ring structures and popcorn transitions for higher charge solitons.
Buchel, Alex; Lehner, Luis
2013-01-01
We construct boson stars in global Anti de Sitter (AdS) space and study their stability. Linear perturbation results suggest that the ground state along with the first three excited state boson stars are stable. We evolve some of these solutions and study their nonlinear stability in light of recent work \\cite{Bizon:2011gg} arguing that a weakly turbulent instability drives scalar perturbations of AdS to black hole formation. However evolutions suggest that boson stars are nonlinearly stable and immune to the instability for sufficiently small perturbation. Furthermore, these studies find other families of initial data which similarly avoid the instability for sufficiently weak parameters. Heuristically, we argue that initial data families with widely distributed mass-energy distort the spacetime sufficiently to oppose the coherent amplification favored by the instability. From the dual CFT perspective our findings suggest that there exist families of rather generic initial conditions in strongly coupled CFT ...
Jatkar, Dileep P; Miskovic, Olivera; Olea, Rodrigo
2014-01-01
We show that the Ashtekar-Magnon-Das (AMD) mass and other conserved quantities are equivalent to the Kounterterm charges in the asymptotically AdS spacetimes that satisfy the Einstein equations, if we assume the same asymptotic fall-off behavior of the Weyl tensor as considered by AMD. This therefore implies that, in all dimensions, the conformal mass can be directly derived from the bulk action and the boundary terms, which are written in terms of the extrinsic curvature.
Refined holographic entanglement entropy for the AdS solitons and AdS black holes
International Nuclear Information System (INIS)
We consider the refinement of the holographic entanglement entropy for the holographic dual theories to the AdS solitons and AdS black holes, including the corrected ones by the Gauss–Bonnet term. The refinement is obtained by extracting the UV-independent piece of the holographic entanglement entropy, the so-called renormalized entanglement entropy which is independent of the choices of UV cutoff. Our main results are: (i) the renormalized entanglement entropies of the AdSd+1 soliton for d=4,5 are neither monotonically decreasing along the RG flow nor positive-definite, especially around the deconfinement/confinement phase transition; (ii) there is no topological entanglement entropy for AdS5 soliton even with Gauss–Bonnet correction; (iii) for the AdS black holes, the renormalized entanglement entropy obeys an expected volume law at IR regime, and the transition between UV and IR regimes is a smooth crossover even with Gauss–Bonnet correction; (iv) based on AdS/MERA conjecture, we postulate that the IR fixed-point state for the non-extremal AdS soliton is a trivial product state
DEFF Research Database (Denmark)
Liu, Yawu; Mattila, Jussi; Ruiz, Miguel �ngel Mu�oz;
2013-01-01
To compare the accuracies of predicting AD conversion by using a decision support system (PredictAD tool) and current research criteria of prodromal AD as identified by combinations of episodic memory impairment of hippocampal type and visual assessment of medial temporal lobe atrophy (MTA) on MRI...
Minces, P; Minces, Pablo; Nunez, Carmen
2006-01-01
Correlation functions of one-unit spectral flowed states in string theory on AdS_3 are considered. We present a formalism which allows to explicitly find the modified Knizhnik-Zamolodchikov and null vector equations to be satisfied by amplitudes of states in w=1 sectors. We give a precise prescription to solve this system of linear differential equations in cases that are relevant to obtain three and four point functions involving spectral flowed string states. We specifically compute three point functions with two and three one-unit spectral flowed operators and also discuss four point functions.
Probing crunching AdS cosmologies
Kumar, S. Prem; Vaganov, Vladislav
2016-02-01
Holographic gravity duals of deformations of CFTs formulated on de Sitter spacetime contain FRW geometries behind a horizon, with cosmological big crunch singularities. Using a specific analytically tractable solution within a particular single scalar truncation of {N}=8 supergravity on AdS4, we first probe such crunching cosmologies with spacelike radial geodesics that compute spatially antipodal correlators of large dimension boundary operators. At late times, the geodesics lie on the FRW slice of maximal expansion behind the horizon. The late time two-point functions factorise, and when transformed to the Einstein static universe, they exhibit a temporal non-analyticity determined by the maximal value of the scale factor ã max. Radial geodesics connecting antipodal points necessarily have de Sitter energy Ɛ ≲ ã max, while geodesics with Ɛ > ã max terminate at the crunch, the two categories of geodesics being separated by the maximal expansion slice. The spacelike crunch singularity is curved "outward" in the Penrose diagram for the deformed AdS backgrounds, and thus geodesic limits of the antipodal correlators do not directly probe the crunch. Beyond the geodesic limit, we point out that the scalar wave equation, analytically continued into the FRW patch, has a potential which is singular at the crunch along with complex WKB turning points in the vicinity of the FRW crunch. We then argue that the frequency space Green's function has a branch point determined by ã max which corresponds to the lowest quasinormal frequency.
Ammon, Martin; Meyer, Rene; O'Bannon, Andy; Wrase, Timm
2009-01-01
Aharony, Bergman, Jafferis, and Maldacena have proposed that the low-energy description of multiple M2-branes at a C4/Zk singularity is a (2+1)-dimensional N=6 supersymmetric U(Nc) x U(Nc) Chern-Simons matter theory, the ABJM theory. In the large-Nc limit, its holographic dual is supergravity in AdS4 x S7/Zk. We study various ways to add fields that transform in the fundamental representation of the gauge groups, i.e. flavor fields, to the ABJM theory. We work in a probe limit and perform analyses in both the supergravity and field theory descriptions. In the supergravity description we find a large class of supersymmetric embeddings of probe flavor branes. In the field theory description, we present a general method to determine the couplings of the flavor fields to the fields of the ABJM theory. We then study four examples in detail: codimension-zero N=3 supersymmetric flavor, described in supergravity by Kaluza-Klein monopoles or D6-branes; codimension-one N=(0,6) supersymmetric chiral flavor, described by...
Holography of AdS vacuum bubbles
International Nuclear Information System (INIS)
We consider the fate of AdS vacua connected by tunneling events. A precise holographic dual of thin-walled Coleman-de Luccia bounces is proposed in terms of Fubini instantons in an unstable CFT. This proposal is backed by several qualitative and quantitative checks, including the precise calculation of the instanton action appearing in evaluating the decay rate. Big crunches manifest themselves as time dependent processes which reach the boundary of field space in a finite time. The infinite energy difference involved is identified on the boundary and highlights the ill-defined nature of the bulk setup. We propose a qualitative scenario in which the crunch is resolved by stabilizing the CFT, so that all attempts at crunching always end up shielded from the boundary by the formation of black hole horizons. In all these well defined bulk processes the configurations have the same asymptotics and are finite energy excitations.
Adamo, Tim; Williams, Jack
2016-01-01
We consider the application of twistor theory to five-dimensional anti-de Sitter space. The twistor space of AdS$_5$ is the same as the ambitwistor space of the four-dimensional conformal boundary; the geometry of this correspondence is reviewed for both the bulk and boundary. A Penrose transform allows us to describe free bulk fields, with or without mass, in terms of data on twistor space. Explicit representatives for the bulk-to-boundary propagators of scalars and spinors are constructed, along with twistor action functionals for the free theories. Evaluating these twistor actions on bulk-to-boundary propagators is shown to produce the correct two-point functions.
Probing crunching AdS cosmologies
Kumar, S Prem
2015-01-01
Holographic gravity duals of deformations of CFTs formulated on de Sitter spacetime contain FRW geometries behind a horizon, with cosmological big crunch singularities. Using a specific analytically tractable solution within a particular single scalar truncation of N=8 supergravity on AdS_4, we first probe such crunching cosmologies with spacelike radial geodesics that compute spatially antipodal correlators of large dimension boundary operators. At late times, the geodesics lie on the FRW slice of maximal expansion behind the horizon. The late time two-point functions factorise, and when transformed to the Einstein static universe, they exhibit a temporal non-analyticity determined by the maximal value of the scale factor a_{max} . Radial geodesics connecting antipodal points necessarily have de Sitter energy E \\leq a_{max}, while geodesics with E > a_{max} terminate at the crunch, the two categories of geodesics being separated by the maximal expansion slice. The spacelike crunch singularity is curved "outw...
Bena, Iosif; Heurtier, Lucien; Puhm, Andrea
2016-05-01
It was argued in [1] that the five-dimensional near-horizon extremal Kerr (NHEK) geometry can be embedded in String Theory as the infrared region of an infinite family of non-supersymmetric geometries that have D1, D5, momentum and KK monopole charges. We show that there exists a method to embed these geometries into asymptotically- {AdS}_3× {S}^3/{{Z}}_N solutions, and hence to obtain infinite families of flows whose infrared is NHEK. This indicates that the CFT dual to the NHEK geometry is the IR fixed point of a Renormalization Group flow from a known local UV CFT and opens the door to its explicit construction.
ADS National Programmes: India
International Nuclear Information System (INIS)
Initial preliminary studies in India on ADS concepts were aimed toward applications such as, one way coupled booster reactor concept, thorium burner concept, enhancement of breeding rate of thorium– fueled fast reactors, and to incinerate Pu and minor actinides discharged from heavy water and fast reactors. These studies led to a roadmap on development of ADS subsystems in India, which was chalked out initially in June 2001. It was realized in these studies that the most challenging subsystem in terms of technology development and capital investment for ADS in India would be the high intensity proton accelerator, and that it must be accomplished in phased manner. Of the two alternative accelerator types, viz. the cyclotron and linear accelerator (linac), it is concluded that only linac would provide the necessary intense beam current for ADS applications. The energy amplifier (EA) scheme, with lead (45.5%) bismuth (55.5%) eutectic (LBE) as target & coolant, which was proposed in the early nineties would be one of the desired configurations of ADS for Indian applications. Additionally, subcritical reactor core of Indian Advanced Heavy Water Reactor (AHWR), with advantages of its low fission power density, and neutron economy is also a candidate among various ADS reactor configurations. These options of ADS configurations for thorium utilization are based on the neutronic properties of 233U isotope as fissile fuel, which are more or less similar in thermal and in moderately fast neutron spectra
Low energy 40Ca + 40Ca collisions
International Nuclear Information System (INIS)
This paper deals with the classical microscopic study of 40Ca + 40Ca collisions. Fusion cross-sections (σsub(CF)) for various incident energies, energy variations with time, shape deformation and the life time of resonance scattering (T) have been studied. Comparison of 40Ca + 40Ca results with those of 16O + 16O have also been made. (author)
Institute of Scientific and Technical Information of China (English)
周源; 李志刚; 周阿剑; 姜婧; 王鑫; 韩向博; 朴赞勋; 宋萌
2015-01-01
目的:探讨音乐电针是否通过减少β淀粉样蛋白1-42(Aβ1-42)的表达,改善阿尔茨海默病(AD)模型快速老化小鼠亚系(SAMP8)小鼠学习记忆行为能力.方法:将20只8月龄SAMP8雄性鼠随机分为模型组、音乐电针组,每组各10只,另设10只抗快速老化小鼠亚系(SAMR1)雄性鼠为正常对照组.音乐电针组针刺百会、印堂后,穴位接人音乐电针仪,选用节奏明朗、速度与力度适中的音乐处方,调节强度以使动物不挣扎嘶叫保持安静为度,每次20 min,1次/d,共15 d;正常组、模型组用相同方法每天用鼠袋束缚20 min.以Moms水迷宫检测小鼠学习记忆能力,免疫组织化学法检测小鼠海马CA3区Aβ1-42表达的影响.结果:Morrs水迷宫检测显示,模型组逃避潜伏期较正常组增加、空间探索实践穿越平台次数减少,靶象限路程占总路程之比明显减少;音乐电针组逃避潜伏期较模型组减少、空间探索实验穿越平台次数增多,靶象限路程占总路程之比明显增多.免疫组化检测显示,正常组的阳性细胞数量少,着色浅;模型组的阳性细胞较正常组明显增多,染色深;音乐电针组的阳性细胞及颜色介于正常组和模型组之间.结论:音乐电针治疗能减少SAMP8小鼠CA3区Aβ1-42的表达,同时能提高AD模型小鼠的学习记忆能力.
Laurent Guiraud
1998-01-01
When the Low-Energy Antiproton Ring (LEAR) was stopped in 1996, because of its costly operation, a cheaper way of continuing low-energy antiproton physics was sought. The Antiproton-Collector (AC), added in 1987 to the Antiproton Accumulator (AA) to provide a tenfold intensity increase, was converted into the Antiproton-Decelerator (AD). Antiprotons from the target at 3.5 GeV/c are decelerated to 100 MeV/c, and fast-ejected to the experiments. Major changes were necessary. Above all, the conversion from a constant-field machine to one with a magnetic cycle, modulating the field by an impressive factor 35. New systems for stochastic and electron cooling had to be added. Beam diagnostics at an intensity of only 2E7 antiprotons was a challenge. In 2000, the AD began delivery of antiprotons to the experiments.
DEFF Research Database (Denmark)
Jensen, Per Anker; Katchamart, Akarapong
2011-01-01
Purpose: To investigate how Facilities Management (FM) can add value and develop a management concept that can assist facilities managers in implementing value adding strategies and practices. Theory: The study is based on the management model for FM included in the European FM standards, recent...... theories on added value of FM and real estate and the related concept of Value Management from building projects. The study is related to the EuroFM research group on The Added Value of FM. Design/methodology/approach: The study outlines a preliminary theoretical based management concept, which...... is investigated, tested and discussed based on a case study of an international corporation. Findings: The study shows that the management model for FM creates a relevant starting point but also that stakeholder and relationship management is an essential aspect of Value Adding Management. The case study confirms...
Hoy, Darrell; Jain, Kamal; Wilkens, Christopher A.
2012-01-01
A single advertisement often benefits many parties, for example, an ad for a Samsung laptop benefits Microsoft. We study this phenomenon in search advertising auctions and show that standard solutions, including the status quo ignorance of mutual benefit and a benefit-aware Vickrey-Clarke-Groves mechanism, perform poorly. In contrast, we show that an appropriate first-price auction has nice equilibria in a single-slot ad auction --- all equilibria that satisfy a natural cooperative envy-freen...
Bena, Iosif; Puhm, Andrea
2015-01-01
It was argued in arXiv:1203.4227 that the five-dimensional near-horizon extremal Kerr (NHEK) geometry can be embedded in String Theory as the infrared region of an infinite family of non-supersymmetric geometries that have D1, D5, momentum and KK monopole charges. We show that there exists a method to embed these geometries into asymptotically-AdS_3 x S^3/Z_N solutions, and hence to obtain infinite families of flows whose infrared is NHEK. This indicates that the CFT dual to the NHEK geometry is the IR fixed point of a Renormalization Group flow from a known local UV CFT and opens the door to its explicit construction.
International Nuclear Information System (INIS)
We describe hadronization events, using the AdS/CFT Correspondence, which display many of the qualitative features expected in QCD. In particular we study the motion of strings with separating end points in a back-reacted hard wall geometry. The solutions show the development of a linear QCD-like string. The end points oscillate in the absence of string breaking. We introduce string breaking by hand and evolve the new state forward in time to observe the separation of two string segments. A kink associated with this breaking evolves to the end points of the string inducing rho meson production. We explicitly compute the rho meson production at the end point.
AdS backgrounds from black hole horizons
International Nuclear Information System (INIS)
We utilize the classification of IIB horizons with 5-form flux to present a unified description for the geometry of AdSn, n = 3, 5, 7 solutions. In particular, we show that all such backgrounds can be constructed from eight-dimensional 2-strong Calabi–Yau geometries with torsion which admit some additional isometries. We explore the geometry of AdS3 and AdS5 solutions but we do not find AdS7 solutions. (paper)
ADS National Programmes: Italy
International Nuclear Information System (INIS)
Following a preliminary design developed in 1998, based on the Energy Amplifier concept proposed by CERN, a first configuration of a lead-bismuth Eutectic cooled Experimental ADS (LBE-XADS) was worked out in the period 1999–2001, under the aegis of MURST, by a group of Italian organizations led by Ansado Nucleare, with the aim of assessing the feasibility of a small sized (80 MWth) ADS. At the end of 1997 a joint effort of ENEA (National Agency for New Technology, Energy and the Environment) and INFN (National Institute for Nuclear Physics) led to the approval of a national programme by MURST (Minister for University and Scientific and Technological Research) named TRASCO (TRAsmutazione SCOrie) aiming at the study of physics and technologies needed to design an ADS for radioactive waste transmutation. The programme consisted of research subprogrammes on accelerator, neutronics, thermalhydraulics analysis, beam window technology, and material technology and compatibility with Pb and Pb-Bi. At now, most of the activities in support to the ADS development carried out at national level are part of EU-funded Projects. These activities are complemented by the programme agreement (AdP -Accordo di programma), signed between ENEA and the Ministry of Economic Development, which provides in general a range of activities aimed at the development of sustainable nuclear fission systems. Several universities and the national industry are involved, besides ENEA, in the activities
DEFF Research Database (Denmark)
Jensen, Per Anker; Katchamart, Akarapong
2011-01-01
Purpose: To investigate how Facilities Management (FM) can add value and develop a management concept that can assist facilities managers in implementing value adding strategies and practices. Theory: The study is based on the management model for FM included in the European FM standards, recent...... impacts and strategic importance of FM for organisations and can be a practical tool for facilities managers in implementing value adding strategies and practices....... investigated, tested and discussed based on a case study of an international corporation. Findings: The study shows that the management model for FM creates a relevant starting point but also that stakeholder and relationship management is an essential aspect of Value Adding Management. The case study confirms...
ADS National Programmes: China
International Nuclear Information System (INIS)
In China the conceptual study of an ADS concept which lasted for about five years ended in 1999. As one project of the National Basic Research Programme of China (973 Programme) in energy domain, which is sponsored by the China Ministry of Science and Technology (MOST), a five year programme of fundamental research of ADS physics and related technology was launched in 2000 and passed national review at the end of 2005. From 2007, another five year 973 Programme Key Technology Research of Accelerator Driven Subcritical System for Nuclear waste Transmutation started. The research activities were focused on HPPA physics and technology, reactor physics of external source driven subcritical assembly, nuclear data base and material study. For HPPA, a high current injector consisting of an ECR ion source, LEBT and an RFQ accelerating structure of 3.5 MeV has been built and were being improved. In reactor physics study, a series of neutron multiplication experimental study has been carrying out. The VENUS I facility has been constructed as the basic experimental platform for neutronics study in ADS blanket. VENUS I a zero power subcritical neutron multiplying assembly driven by external neutron produced by a pulsed neutron generator or 252Cf neutron source. The theoretical, experimental and simulation studies on nuclear data, material properties and nuclear fuel circulation related to ADS are carried out in order to provide the database for ADS system analysis. China Institute of Atomic Energy (CIAE), Institute of High Energy Physics (IHEP) and other Chinese institutes carried out the MOST project together. Besides CIAE, China Academy of Science (CAS) pays more and more attention to Advanced Nuclear Fuel Cycles (ANFC). A large programme of ANFC, including ADS and Th based nuclear fuel cycle, has been launched by CAS
Rashvand, Habib
2013-01-01
Motivated by the exciting new application paradigm of using amalgamated technologies of the Internet and wireless, the next generation communication networks (also called 'ubiquitous', 'complex' and 'unstructured' networking) are changing the way we develop and apply our future systems and services at home and on local, national and global scales. Whatever the interconnection - a WiMAX enabled networked mobile vehicle, MEMS or nanotechnology enabled distributed sensor systems, Vehicular Ad hoc Networking (VANET) or Mobile Ad hoc Networking (MANET) - all can be classified under new networking s
ADS National Programmes: Belgium
International Nuclear Information System (INIS)
The Belgian activities in the field of Accelerator Driven Systems (ADS) are mainly related to the MYRRHA project development. MYRRHA is an accelerator driven, multi purpose fast neutron spectrum facility for R&D, cooled by a lead-bismuth eutectic. SCK•CEN has started the MYRRHA project as a national programme with several national & international bilateral collaboration agreements; the project has now evolved as an European integrated project in the frame of the IPEUROTRANS (European Commission, Sixth Framework Programme). The MYRRHA ‘Draft-2’ predesign file (completed in the early 2005) has been proposed to the partners as a basis for the XT-ADS machine. After a detailed investigation of potential alternatives, the MYRRHA concept (for the subcritical core, the primary coolant system, the accommodation of experimental rigs, the reactor vessel and the spallation target) has been kept with some modifications to achieve the XT-ADS objectives. The most recent version of the XT-ADS design was presented in the 2007 TWG meeting
ADS National Programmes: Japan
International Nuclear Information System (INIS)
In Japan, the research and development (R&D) activities on partitioning and transmutation (P&T) technology had been promoted under the OMEGA programme since 1988. The main institutes involved in these activities were the Japan Atomic Energy Research Institute (JAERI), the Japan Nuclear Cycle Development Institute (JNC), and the Central Research Institute of Electric Power Industry (CRIEPI). Among these institutes, JAERI had mainly conducted the R&D on ADS. In 1999 and 2000, the Atomic Energy Commission (AEC) of Japan implemented the check and review (C&R) on the P&T technology, and the ADS was considered as one of candidates for transmutation systems together with fast reactors. In 2005, JAERI and JNC were merged and the Japan Atomic Energy Agency (JAEA) was established. In JAEA, the R&D activities on both ADS and fast reactors have been continued. In August, 2008, the AEC of Japan launched the Technical Subcommittee on P&T Technology under the Advisory Committee on R&D, and conducted the discussion about the current state of the art concerning P&T technology in Japan and the future R&D programme. The Subcommittee issued the final report in April, 2009. The final report covered the impact of the P&T technology, the state of the art of the technology, evaluation on the progress of the R&D, and the recommendations of the future R&D. As the basic policy on the P&T technology, the report stated that the R&D should not aim at only the improvement of the P&T performance, but at the achievement of the requirements for whole performance of nuclear power generation. This means that the performance of the Double strata fuel cycle concept should be evaluated from viewpoints of safety, economy, environmental friendliness, saving resource, and non-proliferation of the first stratum as well as those of the second stratum. The Double strata concept, therefore, should be studied as a part of the whole nuclear system both in the transient phase of LWR to FBR and the equilibrium
DEFF Research Database (Denmark)
Holmgreen, Lise-Lotte
2014-01-01
jobs by discursively constructing job ads that appeal to both sexes. This argument is part of the broader field of corporate social responsibility, corporate citizenship, and stakeholder management, which involves discussions of the obligations of corporations to acknowledge and mitigate the......The article asks whether it is not the responsibility of corporations to address the issue of women being underrepresented in Danish management jobs. In other words, it is argued that corporations should be encouraged to engage more actively in the recruitment of both men and women for management...... increasingly widespread impact that their activities have on communities and social structures. The article emphasises the need for more active engagement on the part of corporations by analysing the discursive construction of preferred candidates in a small sample of Danish management job ads. By means of...
Shelah, Saharon
2011-01-01
We address the following question: Can we expand an NIP theory by adding a linear order such that the expansion is still NIP? Easily, if acl(A)=A for all A, then this is true. Otherwise, we give counterexamples. More precisely, there is a totally categorical theory for which every expansion by a linear order has IP. There is also an \\omega-stable NDOP theory for which every expansion by a linear order interprets bounded arithmetic.
ADS National Programmes: France
International Nuclear Information System (INIS)
Studies related to nuclear reactors and radioactive waste started at the French National Centre for Scientific research, CNRS, as a result of the French law on radioactive waste that was published in 1991. They were initially organized around the programme PACE (Physique pour l’Aval du Cycle Electronucléaire = physics of the back end of the nuclear fuel cycle), which became PACEN (Physique pour l’Aval du Cycle et production d’Energie Nucléaire = Physics of the back end of the nuclear fuel cycle and production of nuclear energy) in 2006. Research on accelerator driven systems was from the beginning part of this programme. This research is mainly funded by the National Institute for Nuclear end Particle Physics (IN2P3) of CNRS and within the EURATOM European programmes (FP5, 6 and 7). The programme took place in several stages, and covered various scientific fields, benefitting from expertise of CNRS in the field. More specifically, it aimed and still aims to: – Test and verify the feasibility and design of the ADS concept, in terms of neutronics, physics of materials, design of the accelerator and tests of its prototypical components that have been built (or are at present under construction); – Measure and-or improve nuclear data related to radioactive waste transmutation. Today, most of the activities in support to ADS development carried out by CNRS focus on accelerator developments, GUINEVERE (Generator of Uninterrupted Intense NEutron at the lead VEnus REactor) experiment, ADS core studies, deployment scenarios and nuclear data measurements. The CEA R&D programmes on ADS are mainly focused on the European project EUROTRANS of the 6th Framework programme (2005–2010) and continued in the FREYA project of the 7th Framework Programme
AdS 3-manifolds and Higgs bundles
DEFF Research Database (Denmark)
Alessandrini, Daniele; Li, Qiongling
2015-01-01
In this paper we investigate the relationships between closed AdS 3-manifolds and Higgs bundles. We have a new way to construct AdS structures that allows us to see many of their properties explicitly, for example we can recover the very recent formula by Tholozan for the volumes. We also find...
Evaporation of large black holes in AdS
International Nuclear Information System (INIS)
The AdS/CFT correspondence offers a new perspective on the long-standing black hole information paradox. However, to be able to use the available gauge/gravity machinery one is forced to consider so-called 'large' black holes in AdS, and these objects are thermodynamically stable - they do not evaporate. We describe a simple toy model that allows large AdS black holes to decay, by coupling the emitted radiation to an external scalar field propagating in an auxiliary space. This effectively changes the properties of the boundary of AdS, making it partly absorbing. We demonstrate that the evaporation process never ceases by explicitly presenting (a) the transmission coefficient for a wave scattering from the bulk into auxiliary space and (b) the greybody factor for a black 3-brane in an AdS background. Therefore, the model provides an interesting framework to address the information paradox using AdS/CFT techniques.
Institute of Scientific and Technical Information of China (English)
李小艳
2010-01-01
There is the trend that now people appreciate those who are slim and regard slim even thin people beautiful. The thinner a person is, the more beautiful. Women, born to pursuit beauty, try various means to follow the trend. We all watch TV, and find a lot of advertisements on diet. The effect of them is tremendous. We all know the fact that it is not at all the better mouse trap will catch mouse. The sales methods are more important. If an advertisement is very interesting and seemingly effective, people will be lured by the ad and then try some of the products.
DEFF Research Database (Denmark)
Hillersdal, Line
in the context of the 'ad libitum meal'. The analytical interest is thus what kind of eaters and bodies are enacted in the meal test and what ideas of prevention and treatment are embedded in their standards. Drawing from ongoing empirical work among Danish obesity researchers performing scientific...... producing an eater who: ”shouldn't restrain herself”. Practices of food and eating in the test meal I suggest, will allow us to tackle reductionism by showing the complex cultural context shaping clinical intervention....
International Nuclear Information System (INIS)
In this article we construct the chirality and Dirac operators on fuzzy AdS2. We also derive the discrete spectrum of the Dirac operator which is important in the study of the spectral triple associated to AdS2. It is shown that the degeneracy of the spectrum present in the commutative AdS2 is lifted in the noncommutative case. The way we construct the chirality operator is suggestive of how to introduce the projector operators of the corresponding projective modules on this space. (author)
Dirac Operator on Noncommutative AdS_2
Fakhri, H
2003-01-01
In this article we construct the chirality and Dirac operators on noncommutative AdS_2. We also derive the discrete spectrum of the Dirac operator which is important in the study of the spectral triple associated with AdS_2. It is shown that the degeneracy of the spectrum present in the commutative AdS_2 is lifted in the noncommutative case. The way we construct the chirality operator is suggestive of how to introduce the projector operators of the corresponding projective modules on this space.
Fakhri, Hossein; Imaanpur, Ali
2003-03-01
In this article we construct the chirality and Dirac operators on noncommutative AdS2. We also derive the discrete spectrum of the Dirac operator which is important in the study of the spectral triple associated to AdS2. It is shown that the degeneracy of the spectrum present in the commutative AdS2 is lifted in the noncommutative case. The way we construct the chirality operator is suggestive of how to introduce the projector operators of the corresponding projective modules on this space.
H. Fakhri; Imaanpur, A.
2003-01-01
In this article we construct the chirality and Dirac operators on noncommutative AdS_2. We also derive the discrete spectrum of the Dirac operator which is important in the study of the spectral triple associated with AdS_2. It is shown that the degeneracy of the spectrum present in the commutative AdS_2 is lifted in the noncommutative case. The way we construct the chirality operator is suggestive of how to introduce the projector operators of the corresponding projective modules on this space.
Radius-dependent gauge unification in AdS5
Choi, Kiwoon; Kim, Hyung Do; Kim, Ian-Woo
2002-01-01
We examine the relation of the 4-dimensional low energy coupling of bulk gauge boson in a slice of AdS5 to the 5-dimensional fundamental couplings as a function of the orbifold radius R. This allows us to address the gauge coupling unification in AdS5 by means of the radius running as well as the conventional momentum running. We then compute the radius dependence of 1-loop low energy couplings in generic AdS5 theory with 4-dimensional supersymmetry, and discuss the low energy predictions whe...
Lee, Peter; Ooguri, Hirosi; Park, Jongwon; Tannenhauser, Jonathan
2001-01-01
We study the spectrum of open strings on AdS_2 branes in AdS_3 in an NS-NS background, using the SL(2,R) WZW model. When the brane carries no fundamental string charge, the open string spectrum is the holomorphic square root of the spectrum of closed strings in AdS_3. It contains short and long strings, and is invariant under spectral flow. When the brane carries fundamental string charge, the open string spectrum again contains short and long strings in all winding sectors. However, branes w...
Thermodynamics of Asymptotically Locally AdS Spacetimes
Papadimitriou, I; Papadimitriou, Ioannis; Skenderis, Kostas
2005-01-01
We formulate the variational problem for AdS gravity with Dirichlet boundary conditions and demonstrate that the covariant counterterms are necessary to make the variational problem well-posed. The holographic charges associated with asymptotic symmetries are then rederived via Noether's theorem and `covariant phase space' techniques. This allows us to prove the first law of black hole mechanics for general asymptotically locally AdS black hole spacetimes. We illustrate our discussion by computing the conserved charges and verifying the first law for the four dimensional Kerr-Newman-AdS and the five dimensional Kerr-AdS black holes.
Killing spinors and supersymmetry on AdS
International Nuclear Information System (INIS)
In this paper we construct several supersymmetric theories on AdS5 background. We discuss the proper definition of the Killing equation for the symplectic Majorana spinors required in AdS5 supersymmetric theories. We find that the symplectic Killing spinor equation involves a matrix M in the USp(2N) indices whose role was not recognized previously. Using the correct Killing spinors we explicitly confirm that the particle masses in the constructed theories agree with the predictions of the AdS/CFT correspondence. Finally, we establish correct O(d - 1,2) isometry transformations required to keep the Lagrangian invariant on AdSd
Conical singularities in AdS space time
International Nuclear Information System (INIS)
Full text: In recent years, the study of conformal gauge theories from 10-D has been motivated by the AdSd+1/CFTd correspondence, first conjectured by J. Maldacena. The aim of this work is to consider the d = 4 case by analysing the configuration of the N coincident D3 branes. In this context, the work shows that there is a duality between type IIB string theory in AdS5 x S5 and N = 4 SU(N) Super Yang-Mills Theory in the IR. The AdS5/CFT4 correspondence brought also new approaches to the strong coupling problem in QCD. Nowadays, there is a whole line of works that focus on the low dimensional correspondence AdS4/CFT3, like the application to graphene and topological insulators, and the AdS3/CFT2 correspondence, related with the entanglement entropy. In this work, we consider the vortex configuration solution to the AdS4 and AdS3 space-time. The most important motivation is to discuss the boundary theory resulting from these solutions. We have examined a straightforward approach to a holographic computation of the graphene and entanglement entropy in the presence of the conical singularity. After this analysis, we consider the scalar field in the bulk in the presence of this metrics and work out the compactification modes. Taking the holographic point of view, we study and discuss the resulting Green function. (author)
Directory of Open Access Journals (Sweden)
Hong-Chuan Yang
2007-01-01
Full Text Available We study the energy-efficient configuration of multihop paths with automatic repeat request (ARQ mechanism in wireless ad hoc networks. We adopt a cross-layer design approach and take both the quality of each radio hop and the battery capacity of each transmitting node into consideration. Under certain constraints on the maximum tolerable transmission delay and the required packet delivery ratio, we solve optimization problems to jointly schedule the transmitting power of each transmitting node and the retransmission limit over each hop. Numerical results demonstrate that the path configuration methods can either significantly reduce the average energy consumption per packet delivery or considerably extend the average lifetime of the multihop route.
Thermodynamics of large AdS black holes
International Nuclear Information System (INIS)
We consider leading order quantum corrections to the geometry of large AdS black holes in a spherical reduction of four-dimensional Einstein gravity with negative cosmological constant. The Hawking temperature grows without bound with increasing black hole mass, yet the semiclassical back-reaction on the geometry is relatively mild, indicating that observers in free fall outside a large AdS black hole never see thermal radiation at the Hawking temperature. The positive specific heat of large AdS black holes is a statement about the dual gauge theory rather than an observable property on the gravity side. Implications for string thermodynamics with an AdS infrared regulator are briefly discussed
Supersymmetric Kaluza-Klein reductions of AdS backgrounds
Figueroa-O'Farrill, J M; Farrill, Jos\\'e Figueroa-O'; Sim\\'on, Joan
2004-01-01
This paper contains a classification of smooth Kaluza--Klein reductions (by one-parameter subgroups) of the maximally supersymmetric anti de Sitter backgrounds of supergravity theories. We present a classification of one-parameter subgroups of isometries of anti de Sitter spaces, discuss the causal properties of their orbits on these manifolds, and discuss their action on the space of Killing spinors. We analyse the problem of which quotients admit a spin structure. We then apply these results to write down the list of smooth everywhere spacelike supersymmetric quotients of AdS_3 x S^3 (x R^4), AdS_4 x S^7, AdS_5 x S^5 and AdS_7 x S^4, and the fraction of supersymmetry preserved by each quotient. The results are summarised in tables which should be useful on their own. The paper also includes a discussion of supersymmetry of singular quotients.
ADS National Programmes: Netherlands
International Nuclear Information System (INIS)
The ADS related activities within the Netherlands are concentrated at NRG. From 2000 to 2006, NRG supported SCK•CEN in their development of MYRRHA. The support was mainly devoted to Computational Fluid Dynamics (CFD) simulations for the windowless target option. This collaboration was prolonged within the framework of the EU FP6 EUROTRANS project. Eventually this lead to a solution strategy for the hydraulic (without heat transfer) evaluation of a windowless target with one free surface using an Eulerian-Eulerian modeling approach. As a second free surface was added to the target design later, this approach would need to be revisited. The developed approach was applied to an assess the feasibility of a three feeder windowless target design. This preliminary assessment confirmed that there were no serious show stoppers for a three feeder design. Another study undertaken using related to the windowless target was a preliminary assessment of the risk of lead-bismuth splashing in case of a sudden heat deposition by the beam, e.g. at beam startup or beam interuptions. Within the framework of the EU FP7 CDT project, a window target is currently being assessed thermalhydraulicly in collaboration with SCK•CEN. Within the EU FP5 ASCHLIM project, the state of the art with regard to turbulence modelling for CFD approaches was determined. It was concluded that accurate simulation of heat transport in HLM was not feasible, especially in natural or mixed convection regimes. Within the EU FP7 THINS project this issue is currently being treated. NRG assists the commercial CFD code vendor CD adapco in implementing and testing a promising, academically tested, algebraic heat flux model
Chaos and hydrodynamics near AdS$_2$
Jensen, Kristan
2016-01-01
We revisit AdS$_2$ holography with the Sachdev-Ye-Kitaev models in mind. Our main result is to rewrite a generic theory of gravity near an AdS$_2$ throat as a novel hydrodynamics coupled to the correlation functions of a conformal quantum mechanics. This gives a prescription for the computation of $n$-point functions in the dual quantum mechanics. We thereby find that the dual is maximally chaotic.
Minisuperspace limit of the AdS3 WZNW model
Ribault, Sylvain
2009-01-01
We derive the three-point function of the AdS3 WZNW model in the minisuperspace limit by Wick rotation from the H3+ model. The result is expressed in terms of Clebsch-Gordan coefficients of the Lie algebra sl(2,R). We also introduce a covariant basis of functions on AdS3, which can be interpreted as bulk-boundary propagators.
POSSIBLE CHROMOSPHERIC ACTIVITY CYCLES IN AD LEO
Energy Technology Data Exchange (ETDEWEB)
Buccino, Andrea P.; Petrucci, Romina; Mauas, Pablo J. D. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), C.C. 67 Sucursal 28, C1428EHA-Buenos Aires (Argentina); Jofré, Emiliano [Observatorio Astronómico de Córdoba, Córdoba (Argentina)
2014-01-20
AD Leo (GJ 388) is an active dM3 flare star that has been extensively observed both in the quiescent and flaring states. Since this active star is near the fully convective boundary, studying its long-term chromospheric activity in detail could be an appreciable contribution to dynamo theory. Here, using the Lomb-Scargle periodogram, we analyze the Ca II K line-core fluxes derived from CASLEO spectra obtained between 2001 and 2013 and the V magnitude from the ASAS database between 2004 and 2010. From both of these totally independent time series, we obtain a possible activity cycle with a period of approximately seven years and a less significant shorter cycle of approximately two years. A tentative interpretation is that a dynamo operating near the surface could be generating the longer cycle, while a second dynamo operating in the deep convection zone could be responsible for the shorter one. Based on the long duration of our observing program at CASLEO and the fact that we observe different spectral features simultaneously, we also analyze the relation between simultaneous measurements of the Na I index (R{sub D}{sup ′}), Hα, and Ca II K fluxes at different activity levels of AD Leo, including flares.
POSSIBLE CHROMOSPHERIC ACTIVITY CYCLES IN AD LEO
International Nuclear Information System (INIS)
AD Leo (GJ 388) is an active dM3 flare star that has been extensively observed both in the quiescent and flaring states. Since this active star is near the fully convective boundary, studying its long-term chromospheric activity in detail could be an appreciable contribution to dynamo theory. Here, using the Lomb-Scargle periodogram, we analyze the Ca II K line-core fluxes derived from CASLEO spectra obtained between 2001 and 2013 and the V magnitude from the ASAS database between 2004 and 2010. From both of these totally independent time series, we obtain a possible activity cycle with a period of approximately seven years and a less significant shorter cycle of approximately two years. A tentative interpretation is that a dynamo operating near the surface could be generating the longer cycle, while a second dynamo operating in the deep convection zone could be responsible for the shorter one. Based on the long duration of our observing program at CASLEO and the fact that we observe different spectral features simultaneously, we also analyze the relation between simultaneous measurements of the Na I index (RD′), Hα, and Ca II K fluxes at different activity levels of AD Leo, including flares
ADS National Programmes: Belarus
International Nuclear Information System (INIS)
The Belarus activities in the field of Accelerator Driven Systems (ADS) are mainly related to the investigations performed at the subcritical facility YALINA. Yalina is a zero power subcritical facility to study neutronics of ADS and the transmutation reaction rates. The first assembly YALINA-T was put into operation in 2000. YALINA-T is a multiplying system (kmax<0.98), located inside a graphite reflector of parallelepiped configuration that is arranged of high purity reactor graphite blocks. The core of the assembly is of parallelepiped configuration too and consists of bare polyethylene subassemblies where fuel rods of EK-10 type (UO2 of 10% enrichment by U235) are located. At the core center a neutron producing Pb target is located that reminds fuel subassembly by shape and size. Graphite reflector is covered from outside by Cd. At the distances R=50 mm, 100 mm, 150 mm from the core center three experimental channels (D=25 mm) are situated for location of samples of radioactive targets and various detectors for measurement of neutron flux density functionals. For the same purpose two axial channels (D=25 mm) are located in graphite reflector at the distances 250 mm and 358 mm; by Z=H/2 one more radial channel (D=25 mm) is located. YALINA-B core is arranged of rectangular parallelepipeds too. The fast (booster) zone consists of lead subassemblies, the thermal one of polyethylene subassemblies. Central part of the booster zone, containing highly enriched (90%) metallic uranium fuel and Pb target is encased into a separate stainless steel frame. The absorber zone is located at the outer boundary of the booster zone. It consists of inner layer of rods with metallic natural uranium fixed in lead blocks, as in the previous cases, and of an outer layer of rods filled by boron carbide powder, B4C. Boron carbide rods are located in the same lattice as the uranium fuel pins in the booster zone with pin pitch 16.00 mm. This absorber zone enables fast neutrons to
Discrimination in Online Ad Delivery
Sweeney, Latanya
2013-01-01
A Google search for a person's name, such as "Trevon Jones", may yield a personalized ad for public records about Trevon that may be neutral, such as "Looking for Trevon Jones?", or may be suggestive of an arrest record, such as "Trevon Jones, Arrested?". This writing investigates the delivery of these kinds of ads by Google AdSense using a sample of racially associated names and finds statistically significant discrimination in ad delivery based on searches of 2184 racially associated person...
Constructing the AdS dual of a Fermi liquid: AdS Black holes with Dirac hair
\\vCubrović, Mihailo; Schalm, Koenraad
2010-01-01
We provide new evidence that the holographic dual to a strongly coupled charged Fermi Liquid has a non-zero fermion density in the bulk. We show that the pole-strength of the stable quasiparticle characterizing the Fermi surface is encoded in the spatially averaged AdS probability density of a single normalizable fermion wavefunction in AdS. Recalling Migdal's theorem which relates the pole strength to the Fermi-Dirac characteristic discontinuity in the number density at $\\ome_F$, we conclude that the AdS dual of a Fermi liquid is described by occupied on-shell fermionic modes in AdS. Encoding the occupied levels in the total probability density of the fermion field directly, we show that an AdS Reissner-Nordstr\\"{o}m black hole in a theory with charged fermions has a critical temperature, at which the system undergoes a first-order transition to a black hole with a non-vanishing profile for the bulk fermion field. Thermodynamics and spectral analysis confirm that the solution with non-zero AdS fermion-profil...
ADS National Programmes: Germany
International Nuclear Information System (INIS)
The German R&D programme for ADS development is related to the partitioning and transmutation of spent fuel. This programme is implemented mainly by the three national research centres belonging to the Helmholtz Association, i.e. Karlsruhe Institute of Technology (KIT), Forschungszentrum Jülich (FZJ) in cooperation with the Technical University of Aachen (RWTH Aachen) and the Helmholtz Zentrum Dresden Rossendorf (HZDR). The main purpose of this R&D programme is the prospect to manage the high level radioactive waste such as to reduce the burden on a final repository. P&T does not eliminate the need for a final repository whatever the strategy, but it allows the reduction of the radio-toxicity associated with radioactive waste, the increase of the repository capacity as a consequence of the reduction of masses to be stored and their associated residual heat load. Different fuel cycle scenarios to implement P&T can be envisaged. These scenarios have been evaluated to identify the impact of P&T on the characteristics, number and deployment pace of the installations of the fuel cycle (reprocessing, fuel fabrication, storage etc). Almost all activities conducted in the R&D programme are embedded in European and international projects and initiatives. In the following more details on the relevant components of the R&D programme are summarized
Clark, T E
2016-01-01
Coset methods are used to determine the action of a co-dimension one brane (domain wall) embedded in (d+1)-dimensional AdS space in the Carroll limit in which the speed of light goes to zero. The action is invariant under the non-linearly realized symmetries of the AdS-Carroll spacetime. The Nambu-Goldstone field exhibits a static spatial distribution for the brane with a time varying momentum density related to the brane's spatial shape as well as the AdS-C geometry. The AdS-C vector field dual theory is obtained.
Logarithmic AdS waves and Zwei-Dreibein gravity
International Nuclear Information System (INIS)
We show that the parameter space of Zwei-Dreibein Gravity (ZDG) in AdS3 exhibits critical points, where massive graviton modes coincide with pure gauge modes and new ‘logarithmic’ modes appear, similar to what happens in New Massive Gravity. The existence of critical points is shown both at the linearized level, as well as by finding AdS wave solutions of the full non-linear theory, that behave as logarithmic modes towards the AdS boundary. In order to find these solutions explicitly, we give a reformulation of ZDG in terms of a single Dreibein, that involves an infinite number of derivatives. At the critical points, ZDG can be conjectured to be dual to a logarithmic conformal field theory with zero central charges, characterized by new anomalies whose conjectured values are calculated
Asymptotically AdS spacetimes with a timelike Kasner singularity
Ren, Jie
2016-07-01
Exact solutions to Einstein's equations for holographic models are presented and studied. The IR geometry has a timelike cousin of the Kasner singularity, which is the less generic case of the BKL (Belinski-Khalatnikov-Lifshitz) singularity, and the UV is asymptotically AdS. This solution describes a holographic RG flow between them. The solution's appearance is an interpolation between the planar AdS black hole and the AdS soliton. The causality constraint is always satisfied. The entanglement entropy and Wilson loops are discussed. The boundary condition for the current-current correlation function and the Laplacian in the IR is examined. There is no infalling wave in the IR, but instead, there is a normalizable solution in the IR. In a special case, a hyperscaling-violating geometry is obtained after a dimensional reduction.
Null warped AdS in higher spin gravity
Breunhoelder, Veronika; Grumiller, Daniel; Prohazka, Stefan
2015-01-01
We equip three-dimensional spin-3 gravity in the principal embedding with a new set of boundary conditions that we call "asymptotically null warped AdS". We find a chiral copy of the Polyakov-Bershadsky algebra as asymptotic symmetry algebra, reminiscent of the situation in topologically massive gravity with strict null warped AdS boundary conditions. We prove the invertibility of the map between zuvielbein and metric variables and construct a global gauge transformation to half of AdS spin-3 gravity in the diagonal embedding. This explains why the theory is chiral and why the Polyakov-Bershadsky algebra arises. We then introduce chemical potentials, derive the entropy, free energy, and the holographic response functions, and conclude with a discussion.
International Nuclear Information System (INIS)
In this work we propose an exact microscopic description of maximally symmetric branes in a euclidean AdS3 background. As shown by Bachas and Petropoulos, the most important such branes are localized along a euclidean AdS2 is contained in AdS3. We provide explicit formulas for the coupling of closed strings to such branes (boundary states) and for the spectral density of open strings. The latter is computed in two different ways first in terms of the open string reflection amplitude and then also from the boundary states by world-sheet duality. This gives rise to an important Cardy type consistency check. All the results are compared in detail with the geometrical picture. We also discuss a second class of branes with spherical symmetry and finally comment on some implications for D-branes in a 2D back hole geometry. (author)
New Massive Gravity and AdS4 Counterterms
International Nuclear Information System (INIS)
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS4). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS4 Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS3 gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory.
Detailed ultraviolet asymptotics for AdS scalar field perturbations
Evnin, Oleg
2016-01-01
We present a range of methods suitable for accurate evaluation of the leading asymptotics for integrals of products of Jacobi polynomials in limits when the degrees of some or all polynomials inside the integral become large. The structures in question have recently emerged in the context of effective descriptions of small amplitude perturbations in anti-de Sitter (AdS) spacetime. The limit of high degree polynomials corresponds in this situation to effective interactions involving extreme short-wavelength modes, whose dynamics is crucial for the turbulent instabilities that determine the ultimate fate of small AdS perturbations. We explicitly apply the relevant asymptotic techniques to the case of a self-interacting probe scalar field in AdS and extract a detailed form of the leading large degree behavior, including closed form analytic expressions for the numerical coefficients appearing in the asymptotics.
All AdS7 solutions of type II supergravity
International Nuclear Information System (INIS)
In M-theory, the only AdS7 supersymmetric solutions are AdS7×S4 and its orbifolds. In this paper, we find and classify new supersymmetric solutions of the type AdS7×M3 in type II supergravity. While in IIB none exist, in IIA with Romans mass (which does not lift to M-theory) there are many new ones. We use a pure spinor approach reminiscent of generalized complex geometry. Without the need for any Ansatz, the system determines uniquely the form of the metric and fluxes, up to solving a system of ODEs. Namely, the metric on M3 is that of an S2 fibered over an interval; this is consistent with the Sp(1) R-symmetry of the holographically dual (1,0) theory. By including D8 brane sources, one can numerically obtain regular solutions, where topologically M3≅S3
Entanglement entropy for free scalar fields in AdS
Sugishita, Sotaro
2016-01-01
We compute entanglement entropy for free massive scalar fields in anti-de Sitter (AdS) space. The entangling surface is a minimal surface whose boundary is a sphere at the boundary of AdS. The entropy can be evaluated from the thermal free energy of the fields on a topological black hole by using the replica method. In odd-dimensional AdS, exact expressions of the Renyi entropy S_n are obtained for arbitrary n. We also evaluate 1-loop corrections coming from the scalar fields to holographic entanglement entropy. Applying the results, we compute the leading difference of entanglement entropy between two holographic CFTs related by a renormalization group flow triggered by a double trace deformation. The difference is proportional to the shift of a central charge under the flow.
New massive gravity and AdS(4) counterterms.
Jatkar, Dileep P; Sinha, Aninda
2011-04-29
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS(4)). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS(4) Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS(3) gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory. PMID:21635026
Towards integrability for AdS3/CFT2
International Nuclear Information System (INIS)
We review the recent progress towards applying worldsheet integrability techniques to the AdS3/CFT2 correspondence to find its all-loop S matrix and Bethe–Yang equations. We study in full detail the massive sector of AdS3×S3×T4 superstrings supported by pure Ramond–Ramond (RR) fluxes. The extension of this machinery to accommodate massless modes, to the AdS3×S3×S3×S1 pure-RR background and to backgrounds supported by mixed background fluxes is also reviewed. While the results discussed here were found elsewhere, our presentation sometimes deviates from the one found in the original literature in an effort to be pedagogical and self-contained. (topical review)
Logarithmic conformal field theories and AdS correspondence
Khorrami, A. M. Ghezelbash. M.; Aghamohammadi, A
1998-01-01
We generalize the Maldacena correspondence to the logarithmic conformal field theories. We study the correspondence between field theories in (d+1)-dimensional AdS space and the d-dimensional logarithmic conformal field theories in the boundary of $AdS_{d+1}$. Using this correspondence, we get the n-point functions of the corresponding logarithmic conformal field theory in d-dimensions.
AdS black holes as reflecting cavities
International Nuclear Information System (INIS)
We use the identification between null singularities of correlators in the bulk with time singularities in the boundary correlators to study the analytic structure of time-dependent thermal Green functions using the eikonal approximation for classical solutions in the AdS black hole background. We show that the location of singularities in complex time can be understood in terms of null rays bouncing on the boundaries and singularities of the eternal black hole, giving the picture of a 'reflecting cavity'. We can then extract the general analytic expression for the asymptotic values of the frequencies of quasinormal modes in large AdS black holes.
AdS black holes as reflecting cavities
Amado, Irene
2008-01-01
We use the identification between null singularities of correlators in the bulk with time singularities in the boundary correlators to study the analytic structure of time-dependent thermal Green functions using the eikonal approximation for classical solutions in the AdS black hole background. We show that the location of singularities in complex time can be understood in terms of null rays bouncing on the boundaries and singularities of the eternal black hole, giving the picture of a `reflecting cavity'. We can then extract the general analytic expression for the asymptotic values of the frequencies of quasinormal modes in large AdS black holes.
Smoothed Transitions in Higher Spin AdS Gravity
Banerjee, Shamik; Castro, Alejandra; Hellerman, Simeon; Hijano, Eliot; Lepage-Jutier, Arnaud; Maloney, Alexander; Shenker, Stephen
2012-01-01
We consider CFTs conjectured to be dual to higher spin theories of gravity in AdS_3 and AdS_4. Two dimensional CFTs with W_N symmetry are considered in the lambda=0 (k --> infinity) limit, where they are conjectured to be described by continuous orbifolds. The torus partition function is computed, using reasonable assumptions, and equals that of a free field theory. We find no phase transition at temperatures of order one; the usual Hawking-Page phase transition is removed by the highly degen...
Small black holes in global AdS spacetime
Jokela, Niko; Vuorinen, Aleksi
2015-01-01
We study finite temperature correlation functions and quasinormal modes in a strongly coupled conformal field theory holographically dual to a small black hole in global Anti-de Sitter spacetime. Upon variation of the black hole radius, our results smoothly interpolate between known limits corresponding to large black holes and thermal AdS space, implying that a non-Hermitian eigenvalue problem gets continuously transitioned into a Hermitian one. This provides justification for the use of small black holes as regulators in studies of black hole formation in global AdS spacetime.
Phases of Global AdS Black Holes
Basu, Pallab; Subramanian, P N Bala
2016-01-01
We study the phases of gravity coupled to a charged scalar and gauge field in an asymptotically Anti-de Sitter spacetime ($AdS_4$) in the grand canonical ensemble. For the conformally coupled scalar, an intricate phase diagram is charted out between the four relevant solutions: global AdS, boson star, Reissner-Nordstrom black hole and the hairy black hole. The nature of the phase diagram undergoes qualitative changes as the charge of the scalar is changed, which we discuss. We also discuss the new features that arise in the extremal limit.
Phases of global AdS black holes
Basu, Pallab; Krishnan, Chethan; Subramanian, P. N. Bala
2016-06-01
We study the phases of gravity coupled to a charged scalar and gauge field in an asymptotically Anti-de Sitter spacetime ( AdS 4) in the grand canonical ensemble. For the conformally coupled scalar, an intricate phase diagram is charted out between the four relevant solutions: global AdS, boson star, Reissner-Nordstrom black hole and the hairy black hole. The nature of the phase diagram undergoes qualitative changes as the charge of the scalar is changed, which we discuss. We also discuss the new features that arise in the extremal limit.
Branes in AdS and pp-wave spacetimes
Skenderis, K; Skenderis, Kostas; Taylor, Marika
2002-01-01
We find half supersymmetric AdS-embeddings in AdS_5 x S^5 corresponding to all quarter BPS orthogonal intersections of D3-branes with Dp-branes. A particular case is the Karch-Randall embedding AdS_4 x S^2. We explicitly prove that these embeddings are supersymmetric by showing that the kappa symmetry projections are compatible with half of the target space Killing spinors and argue that all these cases lead to AdS/dCFT dualities involving a CFT with a defect. We also find an asymptotically AdS_4 x S^2 embedding that corresponds to a holographic RG-flow on the defect. We then consider the pp-wave limit of the supersymmetric AdS-embeddings and show how it leads to half supersymmetric D-brane embeddings in the pp-wave background. We systematically analyze D-brane embeddings in the pp-wave background along with their supersymmetry. We construct all supersymmetric D-branes wrapped along the light-cone using operators in the dual gauge theory: the open string states are constructed using defect fields. We also fin...
Positivity of energy for asymptotically locally AdS spacetimes
Cheng, M C N; Cheng, Miranda C.N.; Skenderis, Kostas
2005-01-01
We derive necessary conditions for the spinorial Witten-Nester energy to be well-defined for asymptotically locally AdS spacetimes. We find that the conformal boundary should admit a spinor satisfying certain differential conditions and in odd dimensions the boundary metric should be conformally Einstein. We show that these conditions are satisfied by asymptotically AdS spacetimes. The gravitational energy (obtained using the holographic stress energy tensor) and the spinorial energy are equal in even dimensions and differ by a bounded quantity related to the conformal anomaly in odd dimensions.
Perturbative entanglement thermodynamics for AdS spacetime: renormalization
Mishra, Rohit; Singh, Harvendra
2015-01-01
We study the effect of charged excitations in the AdS spacetime on the first law of entanglement thermodynamics. It is found that `boosted' AdS black holes give rise to a more general form of first law which includes chemical potential and charge density. To obtain this result we have to resort to a second order perturbative calculation of entanglement entropy for small size subsystems. At first order the form of entanglement law remains unchanged even in the presence of charged excitations. ...
Mixed-symmetry fields in AdS(5), conformal fields, and AdS/CFT
Metsaev, R R
2014-01-01
Mixed-symmetry arbitrary spin massive, massless, and self-dual massive fields in AdS(5) are studied. Light-cone gauge actions for such fields leading to decoupled equations of motion are constructed. Light-cone gauge formulation of mixed-symmetry anomalous conformal currents and shadows in 4d flat space is also developed. AdS/CFT correspondence for normalizable and non-normalizable modes of mixed-symmetry AdS fields and the respective boundary mixed-symmetry anomalous conformal currents and shadows is studied. We demonstrate that the light-cone gauge action for massive mixed-symmetry AdS field evaluated on solution of the Dirichlet problem amounts to the light-cone gauge 2-point vertex of mixed-symmetry anomalous shadow. Also we show that UV divergence of the action for mixed-symmetry massive AdS field with some particular value of mass parameter evaluated on the Dirichlet problem amounts to the action of long mixed-symmetry conformal field, while UV divergence of the action for mixed-symmetry massless AdS fi...
AdS (instability: Lessons from the scalar field
Directory of Open Access Journals (Sweden)
Pallab Basu
2015-06-01
Full Text Available We argued in arXiv:1408.0624 that the quartic scalar field in AdS has features that could be instructive for answering the gravitational stability question of AdS. Indeed, the conserved charges identified there have recently been observed in the full gravity theory as well. In this paper, we continue our investigation of the scalar field in AdS and provide evidence that in the Two-Time Formalism (TTF, even for initial conditions that are far from quasi-periodicity, the energy in the higher modes at late times is exponentially suppressed in the mode number. Based on this and some related observations, we argue that there is no thermalization in the scalar TTF model within time-scales that go as ∼1/ϵ2, where ϵ measures the initial amplitude (with only low-lying modes excited. It is tempting to speculate that the result holds also for AdS collapse.
Penrose inequality for asymptotically AdS spaces
Energy Technology Data Exchange (ETDEWEB)
Itkin, Igor [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Oz, Yaron, E-mail: yaronoz@post.tau.ac.il [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel)
2012-02-28
In general relativity, the Penrose inequality relates the mass and the entropy associated with a gravitational background. If the inequality is violated by an initial Cauchy data, it suggests a creation of a naked singularity, thus providing means to consider the cosmic censorship hypothesis. We propose a general form of Penrose inequality for asymptotically locally AdS spaces.
BRST Quantization of String Theory in AdS(3)
Pakman, A
2003-01-01
We study the BRST quantization of bosonic and NSR strings propagating in AdS(3) x N backgrounds. The no-ghost theorem is proved using the Frenkel-Garland-Zuckerman method. Regular and spectrally-flowed representations of affine SL(2,R) appear on an equal footing. Possible generalizations to related curved backgrounds are discussed.
Internet Advertising. Google AdWords versus Facebook Ads
Directory of Open Access Journals (Sweden)
Paul PAŞCU
2014-05-01
Full Text Available This article describes how to use the applications for Internet advertising, Google AdWords and Facebook Ads. Our attempt is to present the advantages and disadvantages of each of them, the costs and benefits, a useful aspect for companies that plan to start advertising campaigns on the Internet.
Entanglement temperature and perturbed AdS3 geometry
Levine, G. C.; Caravan, B.
2016-06-01
Generalizing the first law of thermodynamics, the increase in entropy density δ S (x ) of a conformal field theory (CFT) is proportional to the increase in energy density, δ E (x ) , of a subsystem divided by a spatially dependent entanglement temperature, TE(x ) , a fixed parameter determined by the geometry of the subsystem, crossing over to thermodynamic temperature at high temperatures. In this paper we derive a generalization of the thermodynamic Clausius relation, showing that deformations of the CFT by marginal operators are associated with spatial temperature variations, δ TE(x ) , and spatial energy correlations play the role of specific heat. Using AdS/CFT duality we develop a relationship between a perturbation in the local entanglement temperature of the CFT and the perturbation of the bulk AdS metric. In two dimensions, we demonstrate a method through which direct diagonalizations of the boundary quantum theory may be used to construct geometric perturbations of AdS3 .
AdS5 backgrounds with 24 supersymmetries
Beck, S.; Gutowski, J.; Papadopoulos, G.
2016-06-01
We prove a non-existence theorem for smooth AdS 5 solutions with connected, compact without boundary internal space that preserve strictly 24 supersymmetries. In particular, we show that D = 11 supergravity does not admit such solutions, and that all such solutions of IIB supergravity are locally isometric to the AdS 5 × S 5 maximally supersymmetric background. Furthermore, we prove that (massive) IIA supergravity also does not admit such solutions, provided that the homogeneity conjecture for massive IIA supergravity is valid. In the context of AdS/CFT these results imply that if gravitational duals for strictly mathcal{N}=3 superconformal theories in 4-dimensions exist, they are either singular or their internal spaces are not compact.
AdS5 Backgrounds with 24 Supersymmetries
Beck, S W; Papadopoulos, G
2016-01-01
We prove a non-existence theorem for smooth AdS5 solutions with connected, compact without boundary internal space that preserve strictly 24 supersymmetries. In particular, we show that D=11 supergravity does not admit such solutions, and that all such solutions of IIB supergravity are locally isometric to the AdS_5 * S^5 maximally supersymmetric background. Furthermore, we prove that (massive) IIA supergravity also does not admit such solutions, provided that the homogeneity conjecture for massive IIA supergravity is valid. In the context of AdS/CFT these results imply that if strictly N=3 superconformal theories in 4-dimensions exist, their gravitational dual backgrounds are either singular or their internal spaces are not compact.
DEFF Research Database (Denmark)
Antila, Kari; Lötjönen, Jyrki; Thurfjell, Lennart;
2013-01-01
objective of the PredictAD project was to find and integrate efficient biomarkers from heterogeneous patient data to make early diagnosis and to monitor the progress of AD in a more efficient, reliable and objective manner. The project focused on discovering biomarkers from biomolecular data...
Self-dual warped AdS3 black holes
Chen, Bin; Ning, Bo
2010-12-01
We study a new class of solutions of three-dimensional topological massive gravity. These solutions can be taken as nonextremal black holes, with their extremal counterparts being discrete quotients of spacelike warped AdS3 along the U(1)L isometry. We study the thermodynamics of these black holes and show that the first law is satisfied. We also show that for consistent boundary conditions, the asymptotic symmetry generators form only one copy of the Virasoro algebra with central charge cL=(4νℓ)/(G(ν2+3)), with which the Cardy formula reproduces the black hole entropy. We compute the real-time correlators of scalar perturbations and find a perfect match with the dual conformal field theory (CFT) predictions. Our study provides a novel example of warped AdS/CFT correspondence: the self-dual warped AdS3 black hole is dual to a CFT with nonvanishing left central charge. Moreover, our investigation suggests that the quantum topological massive gravity asymptotic to the same spacelike warped AdS3 in different consistent ways may be dual to different two-dimensional CFTs.
String theory in AdS3 background
International Nuclear Information System (INIS)
In this thesis we study string theory in AdS3 background in the context of AdS/CFT correspondence. We discuss unitarity, modular invariance and closure of operator product expansion (OPE) in the theory. A construction of spacetime conformal field theory from worldsheet affine symmetry due to Giveon, Kutasov and Seiberg is presented. The spacetime CFT has the meaning boundary CFT in AdS/CFT correspondence. The knowledge of two dimensional N extended superconformal algebras is used to construct superstrings on AdS3 x N with extended spacetime supersymmetry. A classification of vacua of superstrings on AdS3 is proposed from the knowledge of superconformal algebras in two dimensions. We present some exact solutions of Kniznik-Zamolodochikov (KZ) equation for SL(2, R) WZNW model for four point functions, which have logarithmic singularities of conformally invariant cross ratios, from a simple ansatz. Some asymptotic solutions with logarithmic behaviour are also presented. We analyze the logarithmic solutions and show that they can give rise to logarithmic operators in the theory. It has been shown by OPE analysis and otherwise that representation with SL(2, R) quantum number j = -1/2 play a very special role. The possibility of contribution oj logarithmic operators to the OPE is discussed. We find that OPE can not close or unitary representations if we include the logarithmic operators in the theory. We discuss the implications of logarithmic operators about the unitarity of the theory. The role of singleton representation is clarified in the context of logarithmic operators in AdS/CFT correspondence. (author)
ADS-EA proposal for clean nuclear energy
International Nuclear Information System (INIS)
Accelerator Driving System (ADS) is a new device for cleaning energy. A high intensity, high power proton beam provided by accelerators is used to drive a sub-critical nuclear reactor. It is safe, reliable and can produce less nuclear waste, and also ca be used to treat the nuclear waste from the classical reactor. An Energy Amplifier (EA), which is composed of three cyclotrons, is one type of ADS. It will be used to produce 14.4 MW proton beam (12 mA, 1.2 GeV) and to operate a 1500 MW nuclear reactor
Observing quantum gravity in asymptotically AdS space
Emelyanov, Slava
2015-12-01
The question is studied of whether an observer can discover quantum gravity in the semiclassical regime. It is shown that it is indeed possible to probe a certain quantum gravity effect by employing an appropriately designed detector. The effect is related to the possibility of having topologically inequivalent geometries in the path-integral approach at the same time. A conformal field theory (CFT) state which is expected to describe the eternal anti-de Sitter (AdS) black hole in the large-N limit is discussed. It is argued under certain assumptions that the black hole boundary should be merely a patch of the entire AdS boundary. This leads then to a conclusion that that CFT state is the ordinary CFT vacuum restricted to that patch. If existent, the bulk CFT operators can behave as the ordinary semiclassical quantum field theory in the large-N limit in the weak sense.
Smoothed transitions in higher spin AdS gravity
International Nuclear Information System (INIS)
We consider CFTs conjectured to be dual to higher spin theories of gravity in AdS3 and AdS4. Two-dimensional CFTs with WN symmetry are considered in the λ = 0 (k → ∞) limit where they are conjectured to be described by continuous orbifolds. The torus partition function is computed, using reasonable assumptions, and equals that of a free-field theory. We find no phase transition at temperatures of order 1; the usual Hawking–Page phase transition is removed by the highly degenerate light states associated with conical defect states in the bulk. Three-dimensional Chern–Simons matter CFTs with vector-like matter are considered on T3, where the dynamics is described by an effective theory for the eigenvalues of the holonomies. Likewise, we find no evidence for a Hawking–Page phase transition at a large level k. (paper)
AdS nonlinear instability: moving beyond spherical symmetry
Dias, Oscar J C
2016-01-01
Anti-de Sitter (AdS) is conjectured to be nonlinear unstable to a weakly turbulent mechanism that develops a cascade towards high frequencies, leading to black hole formation [1,2]. We give evidence that the gravitational sector of perturbations behaves differently from the scalar one studied in [2]. In contrast with [2], we find that not all gravitational normal modes of AdS can be nonlinearly extended into periodic horizonless smooth solutions of the Einstein equation. In particular, we show that even seeds with a single normal mode can develop secular resonances, unlike the spherically symmetric scalar field collapse studied in [2]. Moreover, if the seed has two normal modes, more than one resonance can be generated at third order, unlike the spherical collapse of [2]. We also show that weak turbulent perturbative theory predicts the existence of direct and inverse cascades, with the former dominating the latter for equal energy two-mode seeds.
Ambitwistors, oscillators and massless fields on $AdS_5$
Uvarov, D V
2016-01-01
Positive energy unitary irreducible representations of $SU(2,2)$ can be constructed with the aid of bosonic oscillators in (anti)fundamental representation of $SU(2)_L\\times SU(2)_R$ that are closely related to Penrose twistors. Starting with the correspondence between the doubleton representations, homogeneous functions on projective twistor space and on-shell $SL(2,\\mathbb C)$ generalized Weyl curvature spinors and their low-spin counterparts, we study in the similar way the correspondence between the massless representations, homogeneous functions on ambitwistor space and, via the Penrose transform, with the gauge fields on Minkowski boundary of $AdS_5$. The possibilities of reconstructing massless fields on $AdS_5$ and some applications are also discussed.
The Mixed Phase of Charged AdS Black Holes
Directory of Open Access Journals (Sweden)
Piyabut Burikham
2016-01-01
Full Text Available We study the mixed phase of charged AdS black hole and radiation when the total energy is fixed below the threshold to produce a stable charged black hole branch. The coexistence conditions for the charged AdS black hole and radiation are derived for the generic case when radiation particles carry charge. The phase diagram of the mixed phase is demonstrated for both fixed potential and charge ensemble. In the dual gauge picture, they correspond to the mixed phase of quark-gluon plasma (QGP and hadron gas in the fixed chemical potential and density ensemble, respectively. In the nuclei and heavy-ion collisions at intermediate energies, the mixed phase of exotic QGP and hadron gas could be produced. The mixed phase will condense and evaporate into the hadron gas as the fireball expands.
Semiclassical Virasoro Blocks from AdS$_3$ Gravity
Hijano, Eliot; Perlmutter, Eric; Snively, River
2015-01-01
We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in arXiv:1508.00501, evaluated in locally AdS$_3$ geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block -- in which two external operators become parametrically heavy -- as a certain scattering process involving higher spin gauge fields in AdS$_3$; this approach highlights the chiral nature of Virasoro blocks. These techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.
Semiclassical Virasoro blocks from AdS3 gravity
Hijano, Eliot; Kraus, Per; Perlmutter, Eric; Snively, River
2015-12-01
We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in [1], evaluated in locally AdS3 geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block — in which two external operators become parametrically heavy — as a certain scattering process involving higher spin gauge fields in AdS3; this approach highlights the chiral nature of Virasoro blocks. These techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.
Perturbative entanglement thermodynamics for AdS spacetime: Renormalization
Mishra, Rohit
2015-01-01
We study the effect of charged excitations in the AdS spacetime on the first law of entanglement thermodynamics. It is found that `boosted' AdS black holes give rise to a more general form of first law which includes chemical potential and charge density. To obtain this result we have to resort to a second order perturbative calculation of entanglement entropy for small size subsystems. At first order the form of entanglement law remains unchanged even in the presence of charged excitations. But the thermodynamic quantities have to be appropriately `renormalized' at the second order due to the corrections. We work in the perturbative regime where $T_{thermal}\\ll T_E$.
Universal isolation in the AdS landscape
Danielsson, U H; Vargas, S C
2016-01-01
We study the universal conditions for quantum non-perturbative stability against bubble nucleation for pertubatively stable AdS vacua based on positive energy theorems. We also compare our analysis with the pre-existing ones in the literature carried out within the thin-wall approximation. The aforementioned criterion is then tested in two explicit examples describing massive type IIA string theory compactified on $S^3$ and $S^3\\,\\times\\,S^3$, respectively. The AdS landscape of both classes of compactifications is known to consist of a set of isolated points. The main result is that all critical points respecting the Breitenlohner-Freedaman (BF) bound also turn out be stable at a non-perturbative level. Finally, we speculate on the possible universal features that may be extracted from the above specific examples.
Supersymmetric AdS6 solutions of type IIB supergravity
International Nuclear Information System (INIS)
We study the general requirement for supersymmetric AdS6 solutions in type IIB supergravity. We employ the Killing spinor technique and study the differential and algebraic relations among various Killing spinor bilinears to find the canonical form of the solutions. Our result agrees precisely with the work of Apruzzi et al. (JHEP 1411:099, 2014), which used the pure spinor technique. Hoping to identify the geometry of the problem, we also computed four-dimensional theory through the dimensional reduction of type IIB supergravity on AdS6. This effective action is essentially a non-linear sigma model with five scalar fields parametrizing SL(3,ℝ)/SO(2,1), modified by a scalar potential and coupled to Einstein gravity in Euclidean signature. We argue that the scalar potential can be explained by a subgroup CSO(1,1,1) ⊂SL(3,ℝ) in a way analogous to gauged supergravity
Supersymmetric AdS6 solutions of type IIB supergravity
International Nuclear Information System (INIS)
We study the general requirement for supersymmetric AdS6 solutions in type IIB supergravity. We employ the Killing spinor technique and study the differential and algebraic relations among various Killing spinor bilinears to find the canonical form of the solutions. Our result agrees precisely with the work of Apruzzi et al. (JHEP 1411:099, 2014), which used the pure spinor technique. Hoping to identify the geometry of the problem, we also computed four-dimensional theory through the dimensional reduction of type IIB supergravity on AdS6. This effective action is essentially a non-linear sigma model with five scalar fields parametrizing SL(3,R)/ SO(2,1), modified by a scalar potential and coupled to Einstein gravity in Euclidean signature. We argue that the scalar potential can be explained by a subgroup CSO(1,1,1) is contained in SL(3,R) in a way analogous to gauged supergravity. (orig.)
One loop gauge couplings in AdS5
Choi, Kiwoon; Kim, Ian-Woo
2002-01-01
We calculate the full 1-loop corrections to the low energy coupling of bulk gauge boson in a slice of AdS5 which are induced by generic 5-dimensional scalar, Dirac fermion, and vector fields with arbitrary Z_2 times Z_2' orbifold boundary conditions. In supersymmetric limit, our results correctly reproduce the results obtained by an independent method based on 4-dimensional effective supergravity. This provides a nontrivial check of our results and assures the regularization scheme-independen...
Extended Superconformal Algebras on AdS_{3}
Ito, Katsushi
1998-01-01
We study a supersymmetric extension of the Virasoro algebra on the boundary of the anti-de Sitter space-time AdS_{3}. Using the free field realization of the currents, we show that the world-sheet affine Lie superalgebras osp(1|2)^{(1)}, sl(1|2)^{(1)} and sl(2|2)^{(1)} provide the boundary N=1,2 and 4 extended superconformal algebras, respectively.
Universal Kounterterms in Lovelock AdS gravity
Kofinas, Georgios; Olea, Rodrigo
2008-01-01
We show the universal form of the boundary term (Kounterterm series) which regularizes the Euclidean action and background-independent definition of conserved quantities for any Lovelock gravity theory with AdS asymptotics (including Einstein-Hilbert and Einstein-Gauss-Bonnet). We discuss on the connection of this procedure to the existence of topological invariants and Chern-Simons forms in the corresponding dimensions.
Mellin amplitudes for $AdS_5\\times S^5$
Rastelli, Leonardo
2016-01-01
We revisit the calculation of holographic correlation functions in IIB supergravity on $AdS_5\\times S^5$. Results for four-point functions simplify drastically when expressed in Mellin space. We conjecture a compact formula for the four-point functions of one-half BPS singe-trace operators of arbitrary weight. Our methods rely on general consistency conditions and eschew detailed knowledge of the supergravity effective action.
Spectrum and Statistical Entropy of AdS Black Holes
Vaz, Cenalo; Wijewardhana, L. C. R.
2009-01-01
Popular approaches to quantum gravity describe black hole microstates differently and apply different statistics to count them. Since the relationship between the approaches is not clear, this obscures the role of statistics in calculating the black hole entropy. We address this issue by discussing the entropy of eternal AdS black holes in dimension four and above within the context of a midisuperspace model. We determine the black hole eigenstates and find that they describe the quantization...
Alday-Maldacena duality and AdS Plateau problem
Morozov, A.
2008-01-01
A short summary of approximate approach to the study of minimal surfaces in AdS, based on solving Nambu-Goto equations iteratively. Today, after partial denunciation of the BDS conjecture, this looks like the only constructive approach to understanding the ways of its possible modification and thus to saving the Alday-Maldacena duality. Numerous open technical problems are explicitly formulated throughout the text.
Smooth Causal Patches for AdS Black Holes
Raju, Suvrat
2016-01-01
We review the paradox of low energy excitations about an AdS black hole. An appropriately chosen unitary operator in the boundary theory can create a locally strong excitation near the black hole horizon, whose global energy is small as a result of the gravitational redshift. The paradox is that this seems to violate a general rule of statistical mechanics, which states that an operator with energy parametrically smaller than $k T$ cannot create a significant excitation in a thermal system. W...
AdS sub 3 gravity and conformal field theories
Behrndt, K; Gaida, I
1999-01-01
We present a detailed analysis of AdS sub 3 gravity, the BTZ black hole and the associated conformal field theories (CFTs). In particular we focus on the non-extreme six-dimensional string solution with background metric AdS sub 3 x S sup 3 near the horizon. In addition we introduce momentum modes along the string, corresponding to a BTZ black hole, and a Taub-NUT soliton in the transverse Euclidean space. We show that the AdS sub 3 space-time of this configuration has the spatial geometry of an annulus with a Liouville model at the outer boundary and a two-dimensional black hole at the inner boundary. These CFTs provide the dynamical degrees of freedom of the three-dimensional effective model and, together with the CFT corresponding to S sup 3 , provide a statistical interpretation of the corresponding Bekenstein-Hawking entropy. We test the proposed exact black hole entropy, which should hold to all orders in alpha', by an independent field theoretical analysis including higher-order curvature corrections. ...
SUSY properties of warped AdS$_3$
Jeong, Jaehoon; Yoshida, Kentaroh
2014-01-01
We examine supersymmetric properties of null-warped AdS$_3$, or alternatively Schrodinger geometries, dual to putative warped CFTs in two dimensions. We classify super Schrodinger subalgebras of the superalgebra psu(1, 1$|$2) $\\oplus$ psu(1, 1$|$2) , corresponding to the superconformal algebra of the AdS$_3 \\times$ S$^3$ geometry. We comment on geometric realisations and provide a string theory description with enhanced supersymmetry in terms of intersecting D3-branes. For type IIB supergravity solutions based on T$^{1,1}$, we consider the relationship between five-dimensional Schrodinger solutions and their three-dimensional null-warped counterparts, corresponding to R symmetry twists. Finally, we study a family of null-warped AdS$_3$ solutions in a setting where there is an ambiguity over the R symmetry and confirm that, for examples admitting a KK reduction to three dimensions, the minimisation of a real superpotential of the three-dimensional gauged supergravity captures the central charge and R symmetry.
AdS Field Theory from Conformal Field Theory
Fitzpatrick, A Liam
2012-01-01
We provide necessary and sufficient conditions for a Conformal Field Theory to have a description in terms of a perturbative Effective Field Theory in AdS. The first two conditions are well-known: the existence of a perturbative `1/N' expansion and an approximate Fock space of states generated by a finite number of low-dimension operators. We add a third condition, that the Mellin amplitudes of the CFT correlators must be well-approximated by functions that are bounded by a polynomial at infinity in Mellin space, or in other words, that the Mellin amplitudes have an effective theory-type expansion. We explain the relationship between our conditions and unitarity, and provide an analogy with scattering amplitudes that becomes exact in the flat space limit of AdS. The analysis also yields a simple connection between conformal blocks and AdS diagrams, providing a new calculational tool very much in the spirit of the S-Matrix program. We also begin to explore the potential pathologies associated with higher spin ...
Production of high added value products from eggshells
Castro, Inês; Pinto, D. B.; Maciel, José; Araújo, Ana; Vicente, A.A.; Rocha, Cristina M. R.
2014-01-01
There are an increasing number of food companies addressing sustainable-manufacturing practices as part of social responsibility reporting. The egg processing industry produces several tons of eggshell residues which are a major environmental problem and represent a significant cost for these industries (ca. 0.6 % of sales). The main goal of this work is to produce high added value products, namely collagen and bioactive peptides, using the remnant of collagen extraction from the eggshell mem...
Ultraviolet asymptotics and singular dynamics of AdS perturbations
Craps, Ben; Vanhoof, Joris
2015-01-01
Important insights into the dynamics of spherically symmetric AdS-scalar field perturbations can be obtained by considering a simplified time-averaged theory accurately describing perturbations of amplitude epsilon on time-scales of order 1/epsilon^2. The coefficients of the time-averaged equations are complicated expressions in terms of the AdS scalar field mode functions, which are in turn related to the Jacobi polynomials. We analyze the behavior of these coefficients for high frequency modes. The resulting asymptotics can be useful for understanding the properties of the finite-time singularity in solutions of the time-averaged theory recently reported in the literature. We highlight, in particular, the gauge dependence of this asymptotics, with respect to the two most commonly used gauges. The harsher growth of the coefficients at large frequencies in higher-dimensional AdS suggests strengthening of turbulent instabilities in higher dimensions. In the course of our derivations, we arrive at recursive rel...
Effect of CaO composition on oxidation and burning behaviors of AM50 Mg alloy
Institute of Scientific and Technical Information of China (English)
Jin-Kyu LEE; Shae K. KIM
2011-01-01
Oxidation and burning behaviors were studied for CaO added AM50 Mg composites which were manufactured by conventional melting and casting processes without SF6 protective gas. CaO added AM50 Mg composites show the stable oxidation resistance. while AM50 Mg alloys show the poor oxidation resistance. The effects of CaO addition on the burning resistance under ambient, nitrogen and dry air atmospheres were examined for CaO added AM50 Mg composites. With increasing CaO addition, the burning temperature increases under ambient, nitrogen and dry air atmospheres. The burning temperatures of small test specimen under all conditions greatly increase even by 0.3% CaO (mass fraction) addition into AM50 Mg alloys.
Effects of cerium on as-cast microstructure and mechanical properties of Mg-3Sn-2Ca magnesium alloy
International Nuclear Information System (INIS)
The Mg-3Sn-2Ca-xCe (x = 0-2.0 wt.%) alloys were prepared by permanent mould casting method, the effects of Ce on the as-cast microstructure and mechanical properties of the alloys were investigated. The results indicated that the volume fraction and size of CaMgSn phase in the Mg-3Sn-2Ca alloy respectively were decreased by adding 0.5-2.0 wt.%Ce, and the average size of CaMgSn phase in the Mg-3Sn-2Ca alloys added 1.5 or 2.0 wt.%Ce was relatively smaller. The main phases in the as-cast Mg-3Sn-2Ca alloys with and without adding Ce were α-Mg, CaMgSn and Mg2Ca phases, and Mg12Ce phase were found in the alloys added more than 1.0 wt.%Ce. The addition of Ce improved the tensile and creep properties of Mg-3Sn-2Ca alloy, and the mechanical properties of Mg-3Sn-2Ca alloys added 1.5 or 2.0 wt.%Ce were relatively higher. The strengthening mechanism of Ce-containing Mg-3Sn-2Ca alloys was mainly attributed to the refinement of CaMgSn phase.
California Department of Resources — California Spatial Information System (CaSIL) is a project designed to improve access to geo-spatial and geo-spatial related data information throughout the state...
Entanglement Entropy and Duality in AdS(4)
Bakas, Ioannis
2015-01-01
Small variations of the entanglement entropy \\delta S and the expectation value of the modular Hamiltonian \\delta E are computed holographically for circular entangling curves in the boundary of AdS(4), using gravitational perturbations with general boundary conditions in spherical coordinates. Agreement with the first law of thermodynamics, \\delta S = \\delta E, requires that the line element of the entangling curve remains constant. In this context, we also find a manifestation of electric-magnetic duality for the entanglement entropy and the corresponding modular Hamiltonian, following from the holographic energy-momentum/Cotton tensor duality.
Internal Structure of Charged AdS Black Holes
Bhattacharjee, Srijit; Virmani, Amitabh
2016-01-01
When an electrically charged black hole is perturbed its inner horizon becomes a singularity, often referred to as the Poisson-Israel mass inflation singularity. Ori constructed a model of this phenomenon for asymptotically flat black holes, in which the metric can be determined explicitly in the mass inflation region. In this paper we implement the Ori model for charged AdS black holes. We find that the mass function inflates faster than the flat space case as the inner horizon is approached. Nevertheless, the mass inflation singularity is still a weak singularity: although spacetime curvature becomes infinite, tidal distortions remain finite on physical objects attempting to cross it.
The AdS3 central charge in string theory
International Nuclear Information System (INIS)
We evaluate the vacuum expectation value of the central charge operator in string theory in an AdS3 vacuum. Our calculation provides a rare non-zero one-point function on a spherical worldsheet. The evaluation involves the regularization both of a worldsheet ultraviolet divergence (associated to the infinite volume of the conformal Killing group), and a space-time infrared divergence (corresponding to the infinite volume of space-time). The two divergences conspire to give a finite result, which is the classical general relativity value for the central charge, corrected in bosonic string theory by an infinite series of tree level higher derivative terms.
Small black holes in global AdS spacetime
Jokela, Niko; Pönni, Arttu; Vuorinen, Aleksi
2016-04-01
We study the properties of two-point functions and quasinormal modes in a strongly coupled field theory holographically dual to a small black hole in global anti-de Sitter spacetime. Our results are seen to smoothly interpolate between known limits corresponding to large black holes and thermal AdS space, demonstrating that the Son-Starinets prescription works even when there is no black hole in the spacetime. Omitting issues related to the internal space, the results can be given a field theory interpretation in terms of the microcanonical ensemble, which provides access to energy densities forbidden in the canonical description.
Self-Dual Warped AdS$_3$ Black Holes
Chen, Bin; Ning, Bo
2010-01-01
We propose a new class of solutions of three-dimensional topological massive gravity. These solutions are non-extremal black holes, with their extremal counterparts being discrete quotients of spacelike warped AdS$_3$ along the $U(1)_L$ isometry. We study the thermodynamics of these black holes and show that the first law is satisfied. We also show that for consistent boundary conditions, the asymptotic symmetry generators form only one copy of the Virasoro algebra with central charge $c_L = \\frac{4\
Thermal Fluctuations in a Charged AdS Black Hole
Pourhassan, B
2015-01-01
In this paper, we will analyze the effects of thermal fluctuations on a charged AdS black hole. This will be done by analyzing the corrections to black hole thermodynamics due to these thermal fluctuations. We will demonstrate that the entropy of this black hole get corrected by logarithmic term. We will also calculate other corrections to other important thermodynamic quantities for this black hole. Finally, we will use the corrected value of the specific heat to analyze the phase transition in this system.
Most general AdS_3 boundary conditions
Grumiller, Daniel
2016-01-01
We consider the most general asymptotically anti-de Sitter boundary conditions in three-dimensional Einstein gravity with negative cosmological constant. The metric contains in total twelve independent functions, six of which are interpreted as chemical potentials (or non-normalizable fluctuations) and the other half as canonical boundary charges (or normalizable fluctuations). Their presence modifies the usual Fefferman-Graham expansion. The asymptotic symmetry algebra consists of two sl(2)_k current algebras, the levels of which are given by k=l/(4G_N), where l is the AdS radius and G_N the three-dimensional Newton constant.
AdS Chern-Simons Gravity induces Conformal Gravity
Aros, Rodrigo
2013-01-01
The leitmotif of this paper is the question of whether four- and higher even-dimensional Conformal Gravities do have a Chern-Simons pedigree. We show that Weyl gravity can be obtained as dimensional reduction of a five-dimensional Chern-Simons action for a suitable (gauged-fixed, tractor-like) five-dimensional AdS connection. The gauge-fixing and dimensional reduction program admits a readily generalization to higher dimensions for the case of certain conformal gravities obtained by contractions of the Weyl tensor.
Belin, Alexandre; Hung, Ling-Yan
2015-01-01
We discuss properties of interpolating geometries in three dimensional gravity in the presence of a chiral anomaly. This anomaly, which introduces an unbalance between left and right central charges, is protected under RG flows. For this simple reason it is impossible to gap a system with such an anomaly. Our goal is to discuss how holography captures this basic and robust feature. We demonstrate the absence of a mass gap by analysing the linearized spectrum and holographic entanglement entropy of these backgrounds in the context of AdS$_3$/CFT$_2$.
Internal Structure of Charged AdS Black Holes
Bhattacharjee, Srijit(Astroparticle Physics & Cosmology Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India); Sarkar, Sudipta; Virmani, Amitabh
2016-01-01
When an electrically charged black hole is perturbed its inner horizon becomes a singularity, often referred to as the Poisson-Israel mass inflation singularity. Ori constructed a model of this phenomenon for asymptotically flat black holes, in which the metric can be determined explicitly in the mass inflation region. In this paper we implement the Ori model for charged AdS black holes. We find that the mass function inflates faster than the flat space case as the inner horizon is approached...
Pure Spinors in AdS and Lie Algebra Cohomology
Mikhailov, Andrei
2014-10-01
We show that the BRST cohomology of the massless sector of the Type IIB superstring on AdS5 × S 5 can be described as the relative cohomology of an infinite-dimensional Lie superalgebra. We explain how the vertex operators of ghost number 1, which correspond to conserved currents, are described in this language. We also give some algebraic description of the ghost number 2 vertices, which appears to be new. We use this algebraic description to clarify the structure of the zero mode sector of the ghost number two states in flat space, and initiate the study of the vertices of the higher ghost number.
ADS National Programmes: Russian Federation
International Nuclear Information System (INIS)
Studies on accelerator driven systems (ADS), which be used as burners of long lived radioactive waste accrued due to operation of thermal reactors, first of all, minor actinides (MA), are carried out in some Russian research institutes (ITEP, SSC RF - IPPE, VNIIEF, JINR, RSC KI, IYaI RAN, OKB ‘GIDROPRESS’, VNIITF etc.). These researches are mainly connected with studying physical processes existing in ADS and their parameters and with design studies and substantiation of experimental ADS facilities. One of the most important directions of researches is the acquirement of quite precise and reliable nuclear data on MA with reference to conditions existing in ADS. Now a coordinated programme of researches on measurement and estimation of nuclear data for 22 isotopes of U, Pu, Np, Am, Cm, Bk and Cf in neutron energy range from 0.05 eV up to 30 MeV has been prepared. Development of different variants of ADS has put a task of comparison of their efficiency as burners of MA
Accomazzi, Alberto; Kurtz, M. J.; Henneken, E. A.; Grant, C. S.; Thompson, D.; Luker, J.; Chyla, R.; Murray, S. S.
2014-01-01
In the spring of 1993, the Smithsonian/NASA Astrophysics Data System (ADS) first launched its bibliographic search system. It was known then as the ADS Abstract Service, a component of the larger Astrophysics Data System effort which had developed an interoperable data system now seen as a precursor of the Virtual Observatory. As a result of the massive technological and sociological changes in the field of scholarly communication, the ADS is now completing the most ambitious technological upgrade in its twenty-year history. Code-named ADS 2.0, the new system features: an IT platform built on web and digital library standards; a new, extensible, industrial strength search engine; a public API with various access control capabilities; a set of applications supporting search, export, visualization, analysis; a collaborative, open source development model; and enhanced indexing of content which includes the full-text of astronomy and physics publications. The changes in the ADS platform affect all aspects of the system and its operations, including: the process through which data and metadata are harvested, curated and indexed; the interface and paradigm used for searching the database; and the follow-up analysis capabilities available to the users. This poster describes the choices behind the technical overhaul of the system, the technology stack used, and the opportunities which the upgrade is providing us with, namely gains in productivity and enhancements in our system capabilities.
AdCell: Ad Allocation in Cellular Networks
Alaei, Saeed; Liaghat, Vahid; Pei, Dan; Saha, Barna
2011-01-01
With more than four billion usage of cellular phones worldwide, mobile advertising has become an attractive alternative to online advertisements. In this paper, we propose a new targeted advertising policy for Wireless Service Providers (WSPs) via SMS or MMS- namely {\\em AdCell}. In our model, a WSP charges the advertisers for showing their ads. Each advertiser has a valuation for specific types of customers in various times and locations and has a limit on the maximum available budget. Each query is in the form of time and location and is associated with one individual customer. In order to achieve a non-intrusive delivery, only a limited number of ads can be sent to each customer. Recently, new services have been introduced that offer location-based advertising over cellular network that fit in our model (e.g., ShopAlerts by AT&T) . We consider both online and offline version of the AdCell problem and develop approximation algorithms with constant competitive ratio. For the online version, we assume tha...
No Holography for Eternal AdS Black Holes
Avery, Steven G
2013-01-01
It is generally believed that the eternal AdS black hole is dual to two conformal field theories with compact spatial sections that are together in a thermofield double state. We argue that this proposal is incorrect, and by extension so are the "entanglement=geometry" proposal of Van Raamsdonk and "ER=EPR" proposal of Maldacena and Susskind. We show that in the bulk there is an interaction needed between the two halves of the Hilbert space for connectivity across the horizon; however, there is no such interaction between the CFTs. This rules out the possibility of the dual to the CFTs being the eternal AdS black hole. We argue the correct dual "geometries" resemble the exterior of the black hole outside the stretched horizon but cap off before the global horizon. This disallows the possibility of a shared future (and past) wedge where Alice falling from one side can meet Bob falling from the other. We expect that in the UV complete theory the aforementioned caps will be fuzzballs.
AdS Twistors for Higher Spin Theory
International Nuclear Information System (INIS)
We construct spectra of supersymmetric higher spin theories in D = 4, 5 and 7 from twistors describing massless (super-)particles on AdS spaces. A massless twistor transform is derived in a geometric way from classical kinematics. Relaxing the spin-shell constraints on twistor space gives an infinite tower of massless states of a 'higher spin particle', generalizing previous work of Bandos et al.. This can generically be done in a number of ways, each defining the states of a distinct higher spin theory, and the method provides a systematic way of finding these. We reproduce known results in D = 4, minimal supersymmetric 5- and 7-dimensional models, as well as supersymmetrisations of Vasiliev's Sp-models as special cases. In the latter models a dimensional enhancement takes place, meaning that the theory lives on a space of higher dimension than the original AdS space, and becomes a theory of doubletons. This talk was presented at the XIX-th Max Born Symposium 'Fundamental Interactions and Twistor-Like Methods', September 2004, in Wroclaw, Poland
Bi-Local Fields in AdS${}_5$ Spacetime
Aouda, Kenichi; Toyoda, Haruki
2016-01-01
Recently, the bi-local fields attracts the interest in studying the duality between $O(N)$ vector model and a higher-spin gauge theory in $AdS$ spacetime. In those theories, the bi-local fields are realized as collective one's of the $O(N)$ vector fields, which are the source of higher spin bulk fields. Historically, the bi-local fields are introduced as a candidate of non-local fields by Yukawa. Today, Yukawa's bi-local fields are understood from a viewpoint of relativistic two-particle bound systems, the bi-local systems. We study the relation between the collective bi-local fields out of HS bulk fields and the fields out of bi-local systems embedded in AdS${}_5$ spacetime with warped metric. It is shown that the effective spring tension of the bi-local system depends on the brane, on which the bi-local system is located. In paticular, a tensionless bi-local sytem, being similar to the collective bi-local fields, can be realized on a low-energy visible brane.
Smooth Causal Patches for AdS Black Holes
Raju, Suvrat
2016-01-01
We review the paradox of low energy excitations about an AdS black hole. An appropriately chosen unitary operator in the boundary theory can create a locally strong excitation near the black hole horizon, whose global energy is small as a result of the gravitational redshift. The paradox is that this seems to violate a general rule of statistical mechanics, which states that an operator with energy parametrically smaller than $k T$ cannot create a significant excitation in a thermal system. When we carefully examine the position dependence of the boundary unitary operator that produces the excitation and the bulk observable necessary to detect the anomalously large effect, we find that they do not both fit in a single causal patch. This follows from a remarkable property of position space AdS correlators that we establish explicitly, and resolves the paradox in a generic state of the system, since no combination of observers can both create the excitation and observe its effect. As a special case of our analy...
Conserved charges in timelike warped AdS3 spaces
Donnay, L.; Fernández-Melgarejo, J. J.; Giribet, G.; Goya, A.; Lavia, E.
2015-06-01
We consider the timelike version of warped anti-de Sitter space (WAdS), which corresponds to the three-dimensional section of the Gödel solution of four-dimensional cosmological Einstein equations. This geometry presents closed timelike curves (CTCs), which are inherited from its four-dimensional embedding. In three dimensions, this type of solution can be supported without matter provided the graviton acquires mass. Here, among the different ways to consistently give mass to the graviton in three dimensions, we consider the parity-even model known as new massive gravity (NMG). In the bulk of timelike WAdS3 space, we introduce defects that, from the three-dimensional point of view, represent spinning massive particlelike objects. For this type of source, we investigate the definition of quasilocal gravitational energy as seen from infinity, far beyond the region where the CTCs appear. We also consider the covariant formalism applied to NMG to compute the mass and the angular momentum of spinning particlelike defects and compare the result with the one obtained by means of the quasilocal stress tensor. We apply these methods to special limits in which the WAdS3 solutions coincide with locally AdS3 and locally AdS2×R spaces. Finally, we make some comments about the asymptotic symmetry algebra of asymptotically WAdS3 spaces in NMG.
The CFT dual of AdS gravity with torsion
International Nuclear Information System (INIS)
We consider the Mielke-Baekler model of three-dimensional AdS gravity with torsion, which has gravitational and translational Chern-Simons terms in addition to the usual Einstein-Hilbert action with cosmological constant. It is shown that the topological nature of the model leads to a finite Fefferman-Graham expansion. We derive the holographic stress tensor and the associated Ward identities and show that, due to the asymmetry of the left- and right-moving central charges, a Lorentz anomaly appears in the dual conformal field theory. Both the consistent and the covariant Weyl and Lorentz anomaly are determined, and the Wess-Zumino consistency conditions for the former are verified. Moreover we consider the most general solution with flat boundary geometry, which describes left- and right-moving gravitational waves on AdS3 with torsion, and show that in this case the holographic energy-momentum tensor is given by the wave profiles. The anomalous transformation laws of the wave profiles under diffeomorphisms preserving the asymptotic form of the bulk solution yield the central charges of the dual CFT and confirm the results that appeared earlier on in the literature. Finally we comment on some points concerning the microstate counting for the Riemann-Cartan black hole
Quantum cat map dynamics on AdS$_2$
Axenides, Minos; Nicolis, Stam
2016-01-01
We present a toy model for the chaotic unitary scattering of single particle wave packets on the radial AdS$_2$ geometry of extremal BH horizons. Based on our recent work for the discretization of the AdS$_2$ space-time, which describes a finite and random geometry, by modular arithmetic, we investigate the validity of the eigenstate thermalization hypothesis (ETH), as well as that of the fast scrambling time bound conjecture (STB), for an observer with time evolution operator the quantum Arnol'd cat map (QACM). We find that the QACM, while possessing a linear spectrum, has eigenstates, which can be expressed in closed form, are found to be random and to satisfy the assumptions of the ETH.The implications are that the dynamics is described by a chaotic, unitary, single particle S-matrix, which completely delocalizes and randomizes initial gaussian wave packets . Applying results obtained by Dyson and Falk for the periods of the Arnol'd Cat Map(ACM),which are related to its mixing time, we also find that the t...
Greig, Jenny A; Buckley, Suzanne Mk; Waddington, Simon N; Parker, Alan L; Bhella, David; Pink, Rebecca; Rahim, Ahad A; Morita, Takashi; Nicklin, Stuart A; McVey, John H; Baker, Andrew H
2009-10-01
The binding of coagulation factor X (FX) to the hexon of adenovirus (Ad) 5 is pivotal for hepatocyte transduction. However, vectors based on Ad35, a subspecies B Ad, are in development for cancer gene therapy, as Ad35 utilizes CD46 (which is upregulated in many cancers) for transduction. We investigated whether interaction of Ad35 with FX influenced vector tropism using Ad5, Ad35, and Ad5/Ad35 chimeras: Ad5/fiber(f)35, Ad5/penton(p)35/f35, and Ad35/f5. Surface plasmon resonance (SPR) revealed that Ad35 and Ad35/f5 bound FX with approximately tenfold lower affinities than Ad5 hexon-containing viruses, and electron cryomicroscopy (cryo-EM) demonstrated a direct Ad35 hexon:FX interaction. The presence of physiological levels of FX significantly inhibited transduction of vectors containing Ad35 fibers (Ad5/f35, Ad5/p35/f35, and Ad35) in CD46-positive cells. Vectors were intravenously administered to CD46 transgenic mice in the presence and absence of FX-binding protein (X-bp), resulting in reduced liver accumulation for all vectors. Moreover, Ad5/f35 and Ad5/p35/f35 efficiently accumulated in the lung, whereas Ad5 demonstrated poor lung targeting. Additionally, X-bp significantly reduced lung genome accumulation for Ad5/f35 and Ad5/p35/f35, whereas Ad35 was significantly enhanced. In summary, vectors based on the full Ad35 serotype will be useful vectors for selective gene transfer via CD46 due to a weaker FX interaction compared to Ad5. PMID:19603000
Online Ad Slotting With Cancellations
Constantin, Florin; Muthukrishnan, S; Pal, Martin
2008-01-01
Many advertisers buy advertisements (ads) on the Internet or on traditional media and seek simple, online mechanisms to reserve ad slots in advance. Media publishers represent a vast and varying inventory, and they too seek automatic, online mechanisms for pricing and allocating such reservations. In this paper, we present and study a simple model for auctioning such ad slots in advance. Bidders arrive sequentially and report which slots they are interested in. The seller must decide immediately whether or not to grant a reservation. Our model allows a seller to accept reservations, but possibly cancel the allocations later and pay the bidder a cancellation compensation (bump payment). Our main result is an online mechanism to derive prices and bump payments that is efficient to implement. This mechanism has many desirable properties. It is individually rational; winners have an incentive to be honest and bidding one's true value dominates any lower bid. Our mechanism's efficiency is within a constant fractio...
International Nuclear Information System (INIS)
We present a LEU-ADS design based on an existing Argentine experimental facility, the RA-8 pool type zero power reactor. The versatility of this reactor allows measurement of different core configurations using different fuel enrichment, burnable poison rods, water perturbations and different control rods types in critical or subcritical configurations with an external source. To assess the feasibility of the LEU-ADS, multiplication factors, kinetic parameters, spectra, and time flux evolution were computed. Two external sources were considered: an isotopic 252Cf source, and a D-D pulsed neutron source. Parameters for different core configurations were calculated, and the feasibility of using continuous and pulsed neutron sources was verified.
International Nuclear Information System (INIS)
Conclusions: • The YALINA facility is a unique installation which was designed as a zero power model of real ADS. • It is intended to study neutronics and kinetics of the sub-critical reactors driven by external neutron sources. • The successful operation of this facility is a scientific contribution from the Republic of Belarus, as well as the international team from EC and USA. • The experimental data are used to benchmark and validate methods and computer codes for designing and licensing ADS
Functions of Mg and Mg-CaO mixtures in hot metal desulfurization
Lindström, David; Nortier, Patrice; Sichen, Du
2013-01-01
The mechanisms of hot metal desulfurization using Mg and Mg-CaO mixtures were studied in a newly designed set-up. It was found that most of the added Mg quickly escaped in 2 s. MgS was not formed by homogeneous nucleation but by its formation on the MgO particles originated from oxide shell of the Mg particles. When tiny CaO particles were added together with Mg, the particles efficiently transformed to CaS. It was found that Mg-gas helped the distribution of the CaO particles in the hot meta...
Role of Ca resistance in competitive survival of fluorescent Pseudomonas in soil with high salinity
International Nuclear Information System (INIS)
The Ca2+-resistant strain HR2-6 of Pseudomonas putida was isolated from spinach root grown in a greenhouse in high salinity soil. Since Ca often accumulates in greenhouse soils in Japan due to many years of Ca applications, the role of Ca2+ resistance in the survival of the strain was investigated. To conduct the investigation, Ca2+-sensitive mutants were obtained with UV-irradiation. The Ca2+-sensitive mutant CAS-1 was found to grow as well as the wild type HR2-6 in a TSB medium without added Ca2+, but with 150 mM and 200 mM Ca2+ added, the growth of the Ca2+-sensitive mutants were 7- and 56-fold lower than that of the wild type. In sterile spinach-greenhouse soil (a non-competitive environment), populations of the Ca2+-sensitive mutant and wild-type strain were similar, but in nonsterile greenhouse soil (a competitive environment), populations of the Ca2+-sensitive mutant were 112-fold lower than the wild type after 50 days. These data suggest that Ca2+ resistance can be an important factor in the survival of P. putida in soil that has an accumulation of Ca
Holographic properties in three-dimensional AdS soliton using $AdS_3/CFT_2$
Peng, Yan
2016-01-01
We study the holographic description of a superconductor by the $AdS_{3}/CFT_{2}$ correspondence. The system is constructed with a Maxwell field and a charged scalar field coupled in the (2+1)-dimensional AdS soliton background. With analytical methods, we obtain the exact expression for the critical chemical potential as $\\mu_{c} = 1 + \\sqrt{1+m^2}$, which has also been generalized to higher dimensions as $\\mu_c \\thickapprox a + \\sqrt{m^2-m_{BF}^2}$ in this work. Around the phase transition points, we find a correspondence between the value of the scalar field at the tip and the scalar operator at infinity. We also arrive at the classical second order phase transition threshold exponent $\\beta=\\frac{1}{2}$ as the same as the mean field theory near the critical chemical potential. As the condensation becomes heavier, we show surprisingly that superconducting phases exist only in a certain range of the chemical potential, which is very different from higher-dimensional cases. And for the small enough negative ...
D. David (David); L.F. Hoogerheide (Lennart); H.K. van Dijk (Herman)
2008-01-01
textabstractThis short note presents the R package AdMit which provides flexible functions to approximate a certain target distribution and it provides an efficient sample of random draws from it, given only a kernel of the target density function. The estimation procedure is fully automatic and thu
An Investigation of AdS2 Backreaction and Holography
Engelsöy, Julius; Verlinde, Herman
2016-01-01
We investigate a dilaton gravity model in AdS2 proposed by Almheiri and Polchinski and develop an 1D effective description in terms of a dynamical boundary time with a Schwarzian derivative action. We show that the effective model is equivalent to a 1D version of Liouville theory, and investigate its dynamics and symmetries via a standard canonical framework. We include the coupling to arbitrary conformal matter and analyze the effective action in the presence of possible sources. We compute commutators of local operators at large time separation, and match the result with the time shift due to a gravitational shockwave interaction. We study a black hole evaporation process and comment on the role of entropy in this model.
On jordanian deformations of AdS_5 and supergravity
Hoare, Ben
2016-01-01
We consider various homogeneous Yang-Baxter deformations of the AdS_5 x S^5 superstring that can be obtained from the eta-deformed superstring and related models by singular boosts. The jordanian deformations we obtain in this way behave similarly to the eta-deformed model with regard to supergravity: T dualizing the classical sigma model it is possible to find corresponding solutions of supergravity, which, however, have dilatons that prevent T dualizing back. Hence the backgrounds of these jordanian deformations are not solutions of supergravity. Still, they do satisfy a set of recently found modified supergravity equations which should imply that the corresponding sigma models are scale invariant. The abelian models that we obtain by singular boosts do directly correspond to solutions of supergravity. In addition to our main results we consider contraction limits of our main example, which also do not correspond to supergravity solutions.
Colliding waves on a string in AdS$_3$
Vegh, David
2015-01-01
This paper is concerned with the classical motion of a string in global AdS$_3$. The initially static string stretches between two antipodal points on the boundary circle. Both endpoints are perturbed which creates cusps at a steady rate. The cusps propagate towards the interior where they collide. The behavior of the string depends on the strength of forcing. Three qualitatively different phases can be distinguished: transparent, gray, and black. The transparent region is analogous to a standing wave. In the black phase, there is a horizon on the worldsheet and cusps never reach the other endpoint. The string keeps folding and its length grows linearly over time. In the gray phase, the string still grows linearly. However, cusps do cross to the other side. The transparent and gray regions are separated by a transition point where a logarithmic accumulation of cusps is numerically observed. A simple model reproduces the qualitative behavior of the string in the three phases.
Thermodynamics of charged Lovelock: AdS black holes
Energy Technology Data Exchange (ETDEWEB)
Prasobh, C.B.; Suresh, Jishnu; Kuriakose, V.C. [Cochin University of Science and Technology, Department of Physics, Cochin (India)
2016-04-15
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second-order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime. (orig.)
The Analytic Bootstrap and AdS Superhorizon Locality
Fitzpatrick, A Liam; Poland, David; Simmons-Duffin, David
2012-01-01
We take an analytic approach to the CFT bootstrap, studying the 4-pt correlators of d > 2 dimensional CFTs in an Eikonal-type limit, where the conformal cross ratios satisfy |u| 2\\Delta_\\phi\\ + 2n for each integer n as l -> infinity. We show how the rate of approach is controlled by the twist and OPE coefficient of the leading twist operator in the \\phi\\ x \\phi\\ OPE, and we discuss SCFTs and the 3d Ising Model as examples. Additionally, we show that the OPE coefficients of other large spin operators appearing in the OPE are bounded as l -> infinity. We interpret these results as a statement about superhorizon locality in AdS for general CFTs.
Thermodynamics of charged Lovelock: AdS black holes
International Nuclear Information System (INIS)
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second-order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime. (orig.)
An investigation of AdS2 backreaction and holography
Engelsöy, Julius; Mertens, Thomas G.; Verlinde, Herman
2016-07-01
We investigate a dilaton gravity model in AdS2 proposed by Almheiri and Polchinski [1] and develop a 1d effective description in terms of a dynamical boundary time with a Schwarzian derivative action. We show that the effective model is equivalent to a 1d version of Liouville theory, and investigate its dynamics and symmetries via a standard canonical framework. We include the coupling to arbitrary conformal matter and analyze the effective action in the presence of possible sources. We compute commutators of local operators at large time separation, and match the result with the time shift due to a gravitational shockwave interaction. We study a black hole evaporation process and comment on the role of entropy in this model.
On Information Loss in AdS$_3$/CFT$_2$
Fitzpatrick, A Liam; Li, Daliang; Wang, Junpu
2016-01-01
We discuss information loss from black hole physics in AdS$_3$, focusing on two sharp signatures infecting CFT$_2$ correlators at large central charge $c$: 'forbidden singularities' arising from Euclidean-time periodicity due to the effective Hawking temperature, and late-time exponential decay in the Lorentzian region. We study an infinite class of examples where forbidden singularities can be resolved by non-perturbative effects at finite $c$, and we show that the resolution has certain universal features that also apply in the general case. Analytically continuing to the Lorentzian regime, we find that the non-perturbative effects that resolve forbidden singularities qualitatively change the behavior of correlators at times $t \\sim S_{BH}$, the black hole entropy. This may resolve the exponential decay of correlators at late times in black hole backgrounds. By Borel resumming the $1/c$ expansion of exact examples, we explicitly identify 'information-restoring' effects from heavy states that should correspo...
Correlation Functions of Winding Strings in AdS_3
Minces, Pablo
2008-01-01
We review certain results for amplitudes of spectral flowed operators in string theory on AdS_3. We present the modified Knizhnik-Zamolodchikov and null vector equations to be satisfied by correlators including w=1 operators. We then discuss the three point function of two w=1 and one w=0 operators in the x-basis, and perform a consistency check on the definition of the w=1 operator. We finally exhibit the steps in the calculation of the winding conserving four point functions for operators in arbitrary spectral flowed sectors, both in the m- and x-basis, under the only assumption that at least one of the operators is in the spectral flowed image of the highest weight discrete representation.
International Programmes on ADS: The Asian ADS Network
International Nuclear Information System (INIS)
As the management of radioactive wastes is a common issue for all the countries utilizing nuclear energy and also for those intending to start it, international multilateral collaboration must be of great importance for effective research and development of transmutation technology for long lived nuclides. Collaboration in Asian region, however, had been less active in comparison to European countries, though nuclear power generation would increase significantly in Asia. Considering this context, the former Japan Atomic Energy Research Institute (JAERI) convened the ‘International Symposium on Accelerator driven Transmutation Systems and Asia ADS Network Initiative’ on March 24 and 25, 2003 at Tokyo, Japan in cooperation with Kyoto University, Osaka University, High Energy Accelerator Research Organization and Tokyo Institute of Technology. Through the discussion in the symposium, common understanding was developed in Japanese, Korean and Chinese scientists concerning the importance of establishing an international network among Asian countries to facilitate information exchange for R&D of ADS. Based on this understanding, five workshops were held so far. The workshop covers the national R&D programmes on ADS including subcritical reactor physics, cross-section measurements, high energy particle physics, accelerator technology, material technology and MA fuel technology. From the fifth workshop, information exchange for R&D on innovative fast reactors for nuclear transmutation was also included
Islands of stability and recurrence times in AdS
Green, Stephen R; Lehner, Luis; Liebling, Steven L
2015-01-01
We study the stability of anti-de Sitter (AdS) spacetime to spherically symmetric perturbations of a real scalar field in general relativity. Further, we work within the context of the "two time framework" (TTF) approximation, which describes the leading nonlinear effects for small amplitude perturbations, and is therefore suitable for studying the weakly turbulent instability of AdS---including both collapsing and non-collapsing solutions. We have previously identified a class of quasi-periodic (QP) solutions to the TTF equations, and in this work we analyze their stability. We show that there exist several families of QP solutions that are stable to linear order, and we argue that these solutions represent islands of stability in TTF. We extract the eigenmodes of small oscillations about QP solutions, and we use them to predict approximate recurrence times for generic non-collapsing initial data in the full (non-TTF) system. Alternatively, when sufficient energy is driven to high-frequency modes, as occurs ...
Islands of stability and recurrence times in AdS
Green, Stephen R.; Maillard, Antoine; Lehner, Luis; Liebling, Steven L.
2015-10-01
We study the stability of anti-de Sitter (AdS) spacetime to spherically symmetric perturbations of a real scalar field in general relativity. Further, we work within the context of the "two time framework" (TTF) approximation, which describes the leading nonlinear effects for small amplitude perturbations, and is therefore suitable for studying the weakly turbulent instability of AdS—including both collapsing and noncollapsing solutions. We have previously identified a class of quasiperiodic (QP) solutions to the TTF equations, and in this paper we analyze their stability. We show that there exist several families of QP solutions that are stable to linear order, and we argue that these solutions represent islands of stability in TTF. We extract the eigenmodes of small oscillations about QP solutions, and we use them to predict approximate recurrence times for generic noncollapsing initial data in the full (non-TTF) system. Alternatively, when sufficient energy is driven to high-frequency modes, as occurs for initial data far from a QP solution, the TTF description breaks down as an approximation to the full system. Depending on the higher order dynamics of the full system, this often signals an imminent collapse to a black hole.
Anti-tumor activity of self-charged (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles
Indian Academy of Sciences (India)
Cao Lin; Cao Jiexin; Wang Cong; Che Ping; Pan De’an; Alex A Volinsky
2012-10-01
Non-stoichiometric (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles with anti-tumor activity are synthesized in a sol–gel method by adding excessive Eu3+ and Ca2+ ions to tungsten oxide crystal structure. Colorimetric assay shows that 10 nm (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles can effectively inhibit growth of mammary cancer cells without any harm to normal cells. Nanoparticles are characterized by X-ray diffraction, high resolution transmission electron microscopy and fluorescence optical spectrometry. Nanomaterials, insoluble in synthesized water, have complicated self-charging surfaces that trap mammary cancer cells. Surface self-charging effect is suggested as the inhibition mechanism.
Energy Technology Data Exchange (ETDEWEB)
Fitzpatrick, A.Liam; /Boston U.; Kaplan, Jared; /SLAC
2012-02-14
We show that suitably regulated multi-trace primary states in large N CFTs behave like 'in' and 'out' scattering states in the flat-space limit of AdS. Their transition matrix elements approach the exact scattering amplitudes for the bulk theory, providing a natural CFT definition of the flat space S-Matrix. We study corrections resulting from the AdS curvature and particle propagation far from the center of AdS, and show that AdS simply provides an IR regulator that disappears in the flat space limit.
Facilities Management and Added Value
DEFF Research Database (Denmark)
Jensen, Per Anker
2010-01-01
is based on literature reviews of the most influential journals within the academic fields of FM, Corporate Real Estate Management and Business to Business Marketing and discussions between participants of the research group working on a further exploration and testing of the FM Value Map. Conclusions......Aim: This paper aims to present different models of the concept of the added value of Facilities Management (FM), including the FM Value Map, which forms the basis of research group in EuroFM, and to present some of the results of this research collaboration. Approach and methodology: The paper...... on the aimed output) and the internal resource based view (with a focus on the input from FM and RE). Good relationship management and building on trust shows to be equally important as delivering the agreed services. In order to measure the multi-dimensional components of adding value both qualitative...
MUSICAL ARRANGEMENT OF MEDIA ADS
Chernyshov Alexander V.
2015-01-01
The music-compositional principles of commercial and political advertising and also the self-promotion of electronic media (radio, television, Internet) are considered in this mediatext: from the elementary beeps, symbolic functions, emblems/logos and musical brands to the sound engineering technology to underscore the product's name and the complex synthesis between music and intra movements and color-light design of frames. Simultaneously examines, how the musical arrangement of ethereal ad...
Functional foods for added value
Mark-Herbert, Cecilia
2002-01-01
In this study innovation involves the development of a new product category; i.e. new products, new processes and new business. The development process is conveyed in narratives where a radically new product group, functional foods, is developed. These high-tech food products are associated with added value for the food business as well as for individuals and society at large. In the past decades Swedish food companies have faced an increasing competition. With increased competitive pressures...
International Programmes on ADS: ISTC
International Nuclear Information System (INIS)
The International Science and Technology Center (ISTC) is an intergovernmental organization, created to serve the goal of improving global safety and security. The European Union, Japan, the Russian Federation and the United States of America, on the basis of a multinational agreement, established ISTC in 1992. The ISTC focused its efforts on funding research projects related to key safety and security technologies including advanced nuclear technology. Since the first ISTC funded project in 1994, Accelerator Driven Systems, Transmutation research and a holistic approach to the nuclear fuel cycle were the areas where ISTC made a real impact on international development in these fields. Given the international dimension of the problem, the research communities of the ISTC member states quickly realized that ISTC projects offered a very flexible and fruitful cooperation platform to address many difficult issues of the nuclear fuel cycle. Highly competent expert communities of ISTC member states benefited from a well defined and transparent mode of operation of ISTC and objective oriented project funding strategy. The ISTC projects related to transmutation of radioactive waste and ADS can be classified in the following thematic areas: - ADS concepts; - Accelerator development; - Spallation target studies; - Nuclear data and spallation process studies; - Minor actinides studies related to ADS; - Partitioning and extraction
Lazrak, A; Peres, A; Giovannardi, S; Peracchia, C
1994-09-01
In Novikoff hepatoma cell pairs studied by double perforated patch clamp (DPPC), brief (20 s) exposure to 20 microM arachidonic acid (AA) induced a rapid and reversible uncoupling. In pairs studied by double whole-cell clamp (DWCC), uncoupling was completely prevented by effective buffering of Cai2+ with BAPTA. Similarly, AA (20 s) had no effect on coupling in cells perfused with solutions containing no added Ca2+ (SES-no-Ca) and studied by DPPC, suggesting that Ca2+ influx plays an important role. Parallel experiments monitoring [Ca2+]i with fura-2 showed that [Ca2+]i increases with AA to 0.7-1.5 microM in normal [Ca2+]o, and to approximately 400 nM in SES-no-Ca solutions. The rate of [Ca2+]i increase matched that of Gj decrease, but [Ca2+]i recovery was faster. In cells studied by DWCC with 2 mM BAPTA in the pipette solution and superfused with SES-no-Ca, long exposure (1 min) to 20 microM AA caused a slow and virtually irreversible uncoupling. This result suggests that AA has a dual mechanism of uncoupling: one dominant, fast, reversible, and Ca(2+)-dependent, the other slow, poorly reversible, and Ca(2+)-independent. In contrast, uncoupling by oleic acid (OA) or halothane was insensitive to internal buffering with BAPTA, suggesting a Ca(2+)-independent mechanism only. PMID:7811915
International Nuclear Information System (INIS)
We present a comprehensive analysis of the AdS/Ricci-flat correspondence, a map between a class of asymptotically locally AdS spacetimes and a class of Ricci-flat spacetimes. We provide a detailed derivation of the map, discuss a number of extensions and apply it to a number of important examples, such as AdS on a torus, AdS black branes and fluids/gravity metrics. In particular, the correspondence links the hydrodynamic regime of asymptotically flat black p-branes or the Rindler fluid with that of AdS. It implies that this class of Ricci-flat spacetimes inherits from AdS a generalized conformal symmetry and has a holographic structure. We initiate the discussion of holography by analyzing how the map acts on boundary conditions and holographic 2-point functions
Caldarelli, M M; Goutéraux, B; Skenderis, K
2014-01-01
We present a comprehensive analysis of the AdS/Ricci-flat correspondence, a map between a class of asymptotically locally AdS spacetimes and a class of Ricci-flat spacetimes. We provide a detailed derivation of the map, discuss a number of extensions and apply the map to a number of important examples, such as AdS on a torus, AdS black branes and fluids/gravity metrics. In particular, the map links the hydrodynamic regime of asymptotically flat black $p$-branes or the Rindler fluid with that of AdS. The map implies that this class of Ricci-flat spacetimes inherits from AdS a generalized conformal symmetry and has a holographic structure. We initiate the discussion of holography by analyzing how the map acts on boundary conditions and holographic 2-point functions.
Magnetic Mass in 4D AdS Gravity
Araneda, Rene; Miskovic, Olivera; Olea, Rodrigo
2016-01-01
We provide a fully-covariant expression for the diffeomorphic charge in 4D anti-de Sitter gravity, when the Gauss-Bonnet and Pontryagin terms are added to the action. The couplings of these topological invariants are such that the Weyl tensor and its dual appear in the on-shell variation of the action, and such that the action is stationary for asymptotic (anti) self-dual solutions in the Weyl tensor. In analogy with Euclidean electromagnetism, whenever the self-duality condition is global, both the action and the total charge are identically vanishing. Therefore, for such configurations the magnetic mass equals the Ashtekhar-Magnon-Das definition.
Magnetic mass in 4D AdS gravity
Araneda, René; Aros, Rodrigo; Miskovic, Olivera; Olea, Rodrigo
2016-04-01
We provide a fully covariant expression for the diffeomorphic charge in four-dimensional anti-de Sitter gravity, when the Gauss-Bonnet and Pontryagin terms are added to the action. The couplings of these topological invariants are such that the Weyl tensor and its dual appear in the on-shell variation of the action and such that the action is stationary for asymptotic (anti-)self-dual solutions in the Weyl tensor. In analogy with Euclidean electromagnetism, whenever the self-duality condition is global, both the action and the total charge are identically vanishing. Therefore, for such configurations, the magnetic mass equals the Ashtekhar-Magnon-Das definition.
Canonical energy and hairy AdS black holes
Hyun, Seungjoon; Park, Sang-A.; Yi, Sang-Heon
2016-08-01
We propose the modified version of the canonical energy which was introduced originally by Hollands and Wald. Our construction depends only on the Euler-Lagrange expression of the system and thus is independent of the ambiguity in the Lagrangian. After some comments on our construction, we briefly mention on the relevance of our construction to the boundary information metric in the context of the AdS/CFT correspondence. We also study the stability of three-dimensional hairy extremal black holes by using our construction.
Stability of Charged Global AdS$_4$ Spacetimes
Arias, Raúl; Serantes, Alexandre
2016-01-01
We study linear and nonlinear stability of asymptotically AdS$_4$ solutions in Einstein-Maxwell-scalar theory. After summarizing the set of static solutions we first examine thermodynamical stability in the grand canonical ensemble and the phase transitions that occur among them. In the second part of the paper we focus on nonlinear stability in the microcanonical ensemble by evolving radial perturbations numerically. We find hints of an instability corner for vanishingly small perturbations of the same kind as the ones present in the uncharged case. Collapses are avoided, instead, if the charge and mass of the perturbations come to close the line of solitons. Finally we examine the soliton solutions. The linear spectrum of normal modes is not resonant and instability turns on at extrema of the mass curve. Linear stability extends to nonlinear stability up to some threshold for the amplitude of the perturbation. Beyond that, the soliton is destroyed and collapses to a hairy black hole. The relative width of t...
Spectrum and statistical entropy of AdS black holes
International Nuclear Information System (INIS)
Popular approaches to quantum gravity describe black hole microstates differently and apply different statistics to count them. Since the relationship between the approaches is not clear, this obscures the role of statistics in calculating the black hole entropy. We address this issue by discussing the entropy of eternal AdS black holes in dimension four and above within the context of a midisuperspace model. We determine the black hole eigenstates and find that they describe the quantization in half integer units of a certain function of the Arnowitt-Deser-Misner (ADM) mass and the cosmological constant. In the limit of a vanishing cosmological constant (the Schwarzschild limit) the quantized function becomes the horizon area and in the limit of a large cosmological constant it approaches the ADM mass of the black holes. We show that in the Schwarzschild limit the area quatization leads to the Bekenstein-Hawking entropy if Boltzmann statistics are employed. In the limit of a large cosmological constant the Bekenstein-Hawking entropy can be recovered only via Bose statistics. The two limits are separated by a first order phase transition, which seems to suggest a shift from ''particlelike'' degrees of freedom at large cosmological constant to geometric degrees of freedom as the cosmological constant approaches zero.
Context: The effect of added sugar intake on ectopic fat accumulation is a subject of debate. Objective: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to examine the potential effect of added sugar intake on ectopic fat depots. Data Sources: MEDLINE, CA...
International Programmes on ADS: IAEA
International Nuclear Information System (INIS)
The IAEA recognizes that there are four major challenges facing the long term development of nuclear energy as a part of the world’s energy mix: improvement of the economic competitiveness, meeting increasingly stringent safety requirements, adhering to the criteria of sustainable development, and public acceptance. Meeting the sustainability criteria is the driving force behind IAEA’s activity in the area of innovative transmutation reactor technology development and, in particular, Accelerator Driven Systems. The framework for all the IAEA activities in the ADS area is the Technical Working Group on Fast Reactors (TWG-FR). In response to strong common R&D needs in the Member States, the TWG-FR acts as a catalyst for international information exchange and collaborative R&D. It provides a forum for exchange of non-commercial scientific and technical information, and a forum for international cooperation on generic research and development programmes on advances in fast reactors and fast spectrum accelerator driven systems. Its present members are the following 15 IAEA Member States: Belarus, Brazil, China, France, Germany, India, Italy, Japan, Kazakhstan, Republic of Korea, Russian Federation, Sweden, Switzerland, United Kingdom, and United States of America, as well as 3 international organizations: ISTC, OECD-NEA, and EU (EC). As observers, the TWG-FR has welcomed Argentina and Belgium. Last but not least, the IAEA is providing the ADS Research and Development Database. It contains information about ADS related R&D programmes, existing and planned experimental facilities as well as programmes, methods and data development efforts, design studies, and so forth
ADS activities in the Netherlands
International Nuclear Information System (INIS)
The problem of long-lived nuclear waste was under consideration in the Netherlands during a number of years. Within this framework different reactor concepts have been considered. One of the most promising concepts appears to be the Accelerator Driven System (ADS) or Fast Energy Amplifier (FEA), as it has been proposed by C. Rubbia of CERN. To unite the effort on accelerator driven reactor concepts in the Netherlands, KEMA, NIKHEF, ECN, KVI, and IRI have joined their forces in a co-operative program since 1996. Cupertino covers the technical fields of nuclear data, reactor physics, and innovative fuels. (author)
Directory of Open Access Journals (Sweden)
J. Swart
1988-09-01
Full Text Available As instructed by the Central Board of the South African Nursing Association during 1985, an investigation was launched into the function of the C.A. Not hard Library, namely to provide optimal information to members. The underlying philosophy concerned with the establishment of the library was to provide a service which is not available elsewhere. The investigation revealed however, that various training institutions in the country meet this need. As a result of the findings, as presented in the article, the C.A. Northard Library was closed on 1 December 1985 as a lending library. A unique Nursing reference library is being established in its place, with the emphasis in the future on the S. A. Nursing Association’s role in the promotion of Nursing research.
Stabilizing ER Ca2+ channel function as an early preventative strategy for Alzheimer's disease.
Directory of Open Access Journals (Sweden)
Shreaya Chakroborty
Full Text Available Alzheimer's disease (AD is a devastating neurodegenerative condition with no known cure. While current therapies target late-stage amyloid formation and cholinergic tone, to date, these strategies have proven ineffective at preventing disease progression. The reasons for this may be varied, and could reflect late intervention, or, that earlier pathogenic mechanisms have been overlooked and permitted to accelerate the disease process. One such example would include synaptic pathology, the disease component strongly associated with cognitive impairment. Dysregulated Ca(2+ homeostasis may be one of the critical factors driving synaptic dysfunction. One of the earliest pathophysiological indicators in mutant presenilin (PS AD mice is increased intracellular Ca(2+ signaling, predominantly through the ER-localized inositol triphosphate (IP(3 and ryanodine receptors (RyR. In particular, the RyR-mediated Ca(2+ upregulation within synaptic compartments is associated with altered synaptic homeostasis and network depression at early (presymptomatic AD stages. Here, we offer an alternative approach to AD therapeutics by stabilizing early pathogenic mechanisms associated with synaptic abnormalities. We targeted the RyR as a means to prevent disease progression, and sub-chronically treated AD mouse models (4-weeks with a novel formulation of the RyR inhibitor, dantrolene. Using 2-photon Ca(2+ imaging and patch clamp recordings, we demonstrate that dantrolene treatment fully normalizes ER Ca(2+ signaling within somatic and dendritic compartments in early and later-stage AD mice in hippocampal slices. Additionally, the elevated RyR2 levels in AD mice are restored to control levels with dantrolene treatment, as are synaptic transmission and synaptic plasticity. Aβ deposition within the cortex and hippocampus is also reduced in dantrolene-treated AD mice. In this study, we highlight the pivotal role of Ca(2+ aberrations in AD, and propose a novel strategy to
Sembiring, Firdaus
2011-01-01
The prepared of film coating calcium alginate chitosan with examined the characteristic has been studied. Making of the film coating performed with interaction polikationik chitosan and polianionik alginate, then added with CaCl2 so that forms astringent. Khelat Ca-alginat chitosan has thickness of 200µm. Analysis SEM shows surface morphology of Ca-alginat chitosan experiences creasing at its surface after experiencing diffusion. Effectivity test Ca-alginat chitosan proved from broadness free...
Entanglement Entropy of AdS Black Holes
Directory of Open Access Journals (Sweden)
Maurizio Melis
2010-11-01
Full Text Available We review recent progress in understanding the entanglement entropy of gravitational configurations for anti-de Sitter gravity in two and three spacetime dimensions using the AdS/CFT correspondence. We derive simple expressions for the entanglement entropy of two- and three-dimensional black holes. In both cases, the leading term of the entanglement entropy in the large black hole mass expansion reproduces exactly the Bekenstein-Hawking entropy, whereas the subleading term behaves logarithmically. In particular, for the BTZ black hole the leading term of the entanglement entropy can be obtained from the large temperature expansion of the partition function of a broad class of 2D CFTs on the torus.
Minimal area submanifolds in AdS x compact
Graham, C Robin
2014-01-01
We describe the asymptotic behavior of minimal area submanifolds in product spacetimes of an asymptotically hyperbolic space times a compact internal manifold. In particular, we find that unlike the case of a minimal area submanifold just in an asymptotically hyperbolic space, the internal part of the boundary submanifold is constrained to be itself a minimal area submanifold. For applications to holography, this tells us what are the allowed "flavor branes" that can be added to a holographic field theory. We also give a compact geometric expression for the spectrum of operator dimensions associated with the slipping modes of the submanifold in the internal space. We illustrate our results with several examples, including some that haven't appeared in the literature before.
Seasonal Sr/Ca, and 44Ca/40Ca co-variation in Arctica islandica
International Nuclear Information System (INIS)
Full text: We have studied the Ca isotopic variations and Sr/Ca ratios within an A. islandica shell in relation to temperature fluctuations of the ambient seawater with sub-seasonal resolution. The long-lived bivalve A. islandica dwells at 10-200 m depth throughout much of the North Atlantic continental shelf. Its shells represent a promising SST archive for boreal marine settings. The A. islandica shell used for this study was collected at 60-m depth near the former position of the Nantucket Shoals Lightship. The years 1956-1958 were analyzed for both, Sr/Ca ratios and δ44/40Ca, with 1957 being the best resolved. The δ44/40Ca are highly correlated with Sr/Ca ratios (r= 0.92 for 1957). The positive correlation of Sr/Ca ratios and temperature in A. islandica is in accordance with published data on other bivalves, but contrary to thermodynamic expectations and e.g. coral data. The same inversion is found for Ca isotope fractionation: the δ44/40Ca correlation with temperature of A. islandica is negative, while all δ44/40Ca temperature gradients published so far (inorganic precipitates and foraminifera data) show varying degrees of positive correlation. Thus, as for Sr/Ca, the temperature correlation of δ44/40Ca in A. islandica is not under thermodynamic control. It appears inevitable to conclude that biological effects dominate both, Sr incorporation and Ca isotope fractionation in A. islandica. Growth rates and food supply are parameters that might relate Sr/Ca ratios as well as Ca isotopic compositions to vital activity and thus indirectly to temperature. In any case the high correlation of Sr/Ca ratios and Ca isotope fractionation indicates a common metabolic process for the observed variations. (author)
From Free Fields to $AdS$ -- III
Gopakumar, R
2005-01-01
In previous work we have shown that large $N$ field theory amplitudes, in Schwinger parametrised form, can be organised into integrals over the stringy moduli space ${\\cal M}_{g,n}\\times R_{+}^n$. Here we flesh this out into a concrete implementation of open-closed string duality. In particular, we propose that the closed string worldsheet is reconstructed from the unique Strebel quadratic differential that can be associated to (the dual of) a field theory skeleton graph. We are led, in the process, to identify the inverse Schwinger proper times ($\\s_i={1\\over \\t_i}$) with the lengths of edges of the critical graph of the Strebel differential. Kontsevich's matrix model derivation of the intersection numbers in moduli space provides a concrete example of this identification. It also exhibits how closed string correlators very naturally emerge from the Schwinger parameter integrals. Finally, to illustrate the utility of our approach to open-closed string duality, we outline a method by which a worldsheet OPE ca...
International Nuclear Information System (INIS)
We use the AdS/CFT correspondence to compute the conductivity of massive N = 2 hypermultiplet fields at finite baryon number density in an N = 4 SU(Nc) super-Yang-Mills theory plasma in the large Nc, large 't Hooft coupling limit. The finite baryon density provides charge carriers analogous to electrons in a metal. An external electric field then induces a finite current which we determine directly. Our result for the conductivity is good for all values of the mass, external field and density, modulo statements about the yet-incomplete phase diagram. In the appropriate limits it agrees with known results obtained from analyzing small fluctuations around equilibrium. For large mass, where we expect a good quasi-particle description, we compute the drag force on the charge carriers and find that the answer is unchanged from the zero density case. Our method easily generalizes to a wide class of systems of probe branes in various backgrounds
DEFF Research Database (Denmark)
Schröder, Philipp J.H.; Sørensen, Allan
2010-01-01
Real-world industries are composed from heterogeneous firms and substantial intra-industry reallocations take place, i.e. high productivity firms squeeze out low productivity firms. Previous tax-tool comparisons have not included these central forces of industry structure. This paper examines a...... general equilibrium monopolistic competition model with heterogeneous firms and intra-industry reallocations. We show that the welfare superiority of ad valorem over unit taxes under imperfect competition is not only preserved but amplified. The additional difference between the tools arises because unit...... taxes distort relative prices, which in turn reduces average industry productivity through reallocations (the survival and increased market share of lower productivity firms). Importantly, numerical solutions of the model reveal that the relative welfare loss from using the unit tax increases...
MUSICAL ARRANGEMENT OF MEDIA ADS
Directory of Open Access Journals (Sweden)
Chernyshov Alexander V.
2015-01-01
Full Text Available The music-compositional principles of commercial and political advertising and also the self-promotion of electronic media (radio, television, Internet are considered in this mediatext: from the elementary beeps, symbolic functions, emblems/logos and musical brands to the sound engineering technology to underscore the product's name and the complex synthesis between music and intra movements and color-light design of frames. Simultaneously examines, how the musical arrangement of ethereal advertising is involved in creation the emotional drama or bravado which reach the level of explicit or associative counterpoint 'music with the advertised object or subject' and which extend to expression of cultural image of all the broadcast channel. The article explores the works of the next genres like infomercial, teleshopping, film-ad, and autonomous commercials that have been produced in European countries or USA.
Increased hippocampal excitability in the 3xTgAD mouse model for Alzheimer's disease in vivo.
Directory of Open Access Journals (Sweden)
Katherine E Davis
Full Text Available Mouse Alzheimer's disease (AD models develop age- and region-specific pathology throughout the hippocampal formation. One recently established pathological correlate is an increase in hippocampal excitability in vivo. Hippocampal pathology also produces episodic memory decline in human AD and we have shown a similar episodic deficit in 3xTg AD model mice aged 3-6 months. Here, we tested whether hippocampal synaptic dysfunction accompanies this cognitive deficit by probing dorsal CA1 and DG synaptic responses in anaesthetized, 4-6 month-old 3xTgAD mice. As our previous reports highlighted a decline in episodic performance in aged control mice, we included aged cohorts for comparison. CA1 and DG responses to low-frequency perforant path stimulation were comparable between 3xTgAD and controls at both age ranges. As expected, DG recordings in controls showed paired-pulse depression; however, paired-pulse facilitation was observed in DG and CA1 of young and old 3xTgAD mice. During stimulus trains both short-latency (presumably monosynaptic: 'direct' and long-latency (presumably polysynaptic: 're-entrant' responses were observed. Facilitation of direct responses was modest in 3xTgAD animals. However, re-entrant responses in DG and CA1 of young 3xTgAD mice developed earlier in the stimulus train and with larger amplitude when compared to controls. Old mice showed less DG paired-pulse depression and no evidence for re-entrance. In summary, DG and CA1 responses to low-frequency stimulation in all groups were comparable, suggesting no loss of synaptic connectivity in 3xTgAD mice. However, higher-frequency activation revealed complex change in synaptic excitability in DG and CA1 of 3xTgAD mice. In particular, short-term plasticity in DG and CA1 was facilitated in 3xTgAD mice, most evidently in younger animals. In addition, re-entrance was facilitated in young 3xTgAD mice. Overall, these data suggest that the episodic-like memory deficit in 3xTgAD mice
Thermodynamic and classical instability of AdS black holes in fourth-order gravity
International Nuclear Information System (INIS)
We study thermodynamic and classical instability of AdS black holes in fourth-order gravity. These include the BTZ black hole in new massive gravity, Schwarzschild-AdS black hole, and higher-dimensional AdS black holes in fourth-order gravity. All thermodynamic quantities which are computed using the Abbot-Deser-Tekin method are used to study thermodynamic instability of AdS black holes. On the other hand, we investigate the s-mode Gregory-Laflamme instability of the massive graviton propagating around the AdS black holes. We establish the connection between the thermodynamic instability and the GL instability of AdS black holes in fourth-order gravity. This shows that the Gubser-Mitra conjecture holds for AdS black holes found from fourth-order gravity
Magnetism of CaAs, CaP, and CaN half-metals
International Nuclear Information System (INIS)
First principles calculations indicate that CaAs, CaP, and CaN compounds are ferromagnets. Analysis of these and other II-V compounds that do not contain transition metal atoms shows that their magnetism derives from the spin polarization of the atomic p(anion) orbitals, which persists in the compounds of Ca, Sr, and Ba due to their large atomic radii
Magnetism of CaAs, CaP, and CaN half-metals
Energy Technology Data Exchange (ETDEWEB)
Volnianska, O. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)]. E-mail: volnian@ifpan.edu.pl; Jakubas, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Boguslawski, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)
2006-10-26
First principles calculations indicate that CaAs, CaP, and CaN compounds are ferromagnets. Analysis of these and other II-V compounds that do not contain transition metal atoms shows that their magnetism derives from the spin polarization of the atomic p(anion) orbitals, which persists in the compounds of Ca, Sr, and Ba due to their large atomic radii.
Which AdS3 configurations contribute to the SCFT2 elliptic genus?
Murthy, S.V.; Nawata, S.
2011-01-01
According to the AdS=CFT duality, the superconformal index of a superconformal eld theory should have an AdS interpretation as a Euclidean functional integral with periodic boundary conditions on the fermions. Unlike the thermal case, the Euclidean continuation of the supersymmetric AdS black hole d
Blomeyer, Christoph A; Bazil, Jason N; Stowe, David F; Dash, Ranjan K; Camara, Amadou K S
2016-06-01
The manner in which mitochondria take up and store Ca(2+) remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca(2+) uptake and a complex Ca(2+) sequestration mechanism in mitochondria. But how Mg(2+) regulates these different modes of Ca(2+) uptake as well as mitochondrial Ca(2+) sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca(2+) by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl2 in the presence or absence of MgCl2. In the first protocol, A, CaCl2 was added to the respiration buffer containing isolated mitochondria, whereas in the second protocol, B, mitochondria were added to the respiration buffer with CaCl2 already present. Protocol A resulted first in a fast transitory uptake followed by a slow gradual uptake. In contrast, protocol B only revealed a slow and gradual Ca(2+) uptake, which was approximately 40 % of the slow uptake rate observed in protocol A. These two types of Ca(2+) uptake modes were differentially modulated by extra-matrix Mg(2+). That is, Mg(2+) markedly inhibited the slow mode of Ca(2+) uptake in both protocols in a concentration-dependent manner, but not the fast mode of uptake exhibited in protocol A. Mg(2+) also inhibited Na(+)-dependent Ca(2+) extrusion. The general Ca(2+) binding properties of the mitochondrial Ca(2+) sequestration system were reaffirmed and shown to be independent of the mode of Ca(2+) uptake, i.e. through the fast or slow mode of uptake. In addition, extra-matrix Mg(2+) hindered Ca(2+) sequestration. Our results indicate that mitochondria exhibit different modes of Ca(2+) uptake depending on the nature of exposure to extra-matrix Ca(2+), which are differentially sensitive to Mg(2+). The implications of these findings in cardiomyocytes are discussed. PMID:26815005
Penedones, Joao
2016-01-01
We introduce the AdS/CFT correspondence as a natural extension of QFT in a fixed AdS background. We start by reviewing some general concepts of CFT, including the embedding space formalism. We then consider QFT in a fixed AdS background and show that one can define boundary operators that enjoy very similar properties as in a CFT, except for the lack of a stress tensor. Including a dynamical metric in AdS generates a boundary stress tensor and completes the CFT axioms. We also discuss some applications of the bulk geometric intuition to strongly coupled QFT. Finally, we end with a review of the main properties of Mellin amplitudes for CFT correlation functions and their uses in the context of AdS/CFT.
Recurring Anomaly Detection System (ReADS)
National Aeronautics and Space Administration — Overview: ReADS can analyze text reports, such as aviation reports and problem or maintenance records. ReADS uses text clustering algorithms to group loosely...
Preparation of CaCu3Ti4O12 using a wet chemical method
International Nuclear Information System (INIS)
CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 degree C. CaCu3Ti4O12 phases was observed after heat treatment at 1000 degree C. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non-stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12. (Author)
Accounting Relations in Bilateral Value Added Trade
Robert Stehrer
2013-01-01
Abstract The increasing international fragmentation of production has triggered the development of a number of widely used indicators accounting for value added ﬂows in the world economy. This paper generalises these measures by simultaneously considering the import side and focusing on bilateral gross and value added trade ﬂows. It discusses how these indicators relate to each other, the role of double counting in bilateral value added trade, and aggregation issues in global value added ﬂows...
Directory of Open Access Journals (Sweden)
Manasvi Kalra,
2016-02-01
Full Text Available The apps consist of advertisements to promote their products. Not all of them are appropriate to resume. Therefore various algorithms have been used in order to block those apps from existence but none of them is completely successful. In our app we are using an antivirus which can by default block those spy apps and remove them from the web page. The algorithm which has been used makes use of various ant viruses in the background which detect irrelevant and intimate apps and then our algorithm will demolish them. Certain apps are non-trustworthy where one click can spy all the mobile data. They block those apps and works on security. We are working on secure ads for mobile apps. It can also work as a basic antivirus where it detects the viruses like malwares in any of your installed apps or downloads. It will create a popup of discarding or keeping it. Mobile applications can be downloaded from anywhere like amazon, googleplay, apps store etc. There is no rigorous verification of an application when it is uploaded to the market. One can easily develop a malicious application and upload it to the app market. The user itself is responsible for accepting the risk of an app available from secondary markets. Therefore, we have decided to develop this app to make the market more secure and bounded. In future, It will take the mobile market while consuming minimal additional resources and preserving user privacy.
Cultural or ethnic changes? Continuity and discontinuity on the Middle Danube ca A.D. 500
Czech Academy of Sciences Publication Activity Database
Tejral, Jaroslav
Paris: Association des amis du Centre dʻhistoire et civilisation de Byzance, 2012, s. 115-188. ISBN 978-2-916716-31-2. [The Pontic-Danubian realm in the period of the Great Migration. Belgrade (RS)] R&D Projects: GA ČR GA404/09/1719 Institutional research plan: CEZ:AV0Z80010507 Keywords : Middle Danube region * Moravia * 5th century * continuity and discontinuity Subject RIV: AC - Archeology, Anthropology, Ethnology http://aleph.nkp.cz/F/?func=direct&doc_number=002430850&local_base=NKC
c-a from the N=1 superconformal index
Ardehali, Arash Arabi; Szepietowski, Phillip
2014-01-01
We present a prescription for obtaining the difference of the central charges, c-a, of a four dimensional superconformal quantum field theory from its single-trace index. The formula is derived from a one-loop holographic computation, but is expected to be valid independent of holography. We demonstrate the prescription with several holographic and non-holographic examples. As an application of our formula, we show the AdS/CFT matching of c-a for arbitrary toric quiver CFTs without adjoint matter that are dual to smooth Sasaki-Einstein 5-manifolds.
Symmetry Breaking, Central Charges and the AdS_2/CFT_1 Correspondence
Cadoni, Mariano; Mignemi, Salvatore
2000-01-01
When two-dimensional Anti-de Sitter space (AdS_2) is endowed with a non-constant dilaton the origin of the central charge in the Virasoro algebra generating the asymptotic symmetries of AdS_2 can be traced back to the breaking of the SL(2,R) isometry group of AdS_2. We use this fact to clarify some controversial results appeared in the literature about the value of the central charge in these models.
Armenta, Almudena; Guerrero, Teresa
2012-01-01
Esta publicación se realiza con motivo de la exposición titulada BOTANyCA celebrada en el Real Jardín Botánico de Madrid del 10 al 21 de octubre de 2012. Dicha exposición fue llevada a cabo por el Grupo de Investigación, Arte, Ciencia y Naturaleza de la Universidad Complutense de Madrid en colaboración con el Real Jardín Botánico. Comisariado de la exposición: Almudena Armenta y Teresa Guerrero. Coordinación técnica: Esther García Guillén y Marga Juárez Canga. Artistas participantes: Almudena...
Reactivity monitoring in ADS systems
International Nuclear Information System (INIS)
Monitoring reactivity in an ADS should be performed on-line with a simple, accurate and robust technique. Within the range of experimental reactor techniques, no single technique can be selected which meet these requirements. Therefore a combination of different techniques has to be chosen in a way that various off-line techniques serve as a calibration for the on-line measurement technique. As an on-line measurement technique, the current/flux reactivity indicator is the most simple and robust solution. It is based on the fact that in a subcritical multiplying medium with a driving source the flux level is proportional to the driving source intensity, hence the beam current, and the reactivity level. However, since the proportionality constant depends on a number of core dependent parameters and detector characteristics, this current-to-flux indicator has to be calibrated on a regular basis. For this calibration, one could benefit from the occurrence of accelerator beam trips to determine the reactivity level in dollars by means of a prompt jump analysis of the flux level change. Hence, the prompt jump reactivity indicator could act as a first calibration tool of the current-to-flux indicator. Since the prompt jump indicator still relies on the value for the effective delayed neutron fraction to determine reactivity level, complementary techniques have to be used to obtain a more accurate determination of the reactivity. Techniques based on reactor noise methods such as RAPJA technique which is combination of the Rossi-alpha method and Prompt jump analysis can be used in this respect. In the future the bi-spectral ratio from the Cf - source driven noise analysis could be used for this purpose. (author)
Historical Literature in the ADS
Eichhorn, G.; Kurtz, M. J.; Accomazzi, A.; Grant, C. S.
1997-12-01
The Astrophysics Data System at http://adswww.harvard.edu is in the process of scanning the historical astronomical literature and making it available through the World Wide Web. We have scanned several volumes from the early 1800's of the "Astronomische Nachrichten", and the "Monthly Notices of the Royal Astronomical Society", the two oldest astronomical journals. We also have several of the early volumes of the "Astrophysical Journal" and the "Astronomical Journal" available. For all the journals that we cover, we have scanned volume 1. These early volumes can be accessed on a page-by-page basis. We plan to continue to scan this historical literature and complete these journals within the next year. We are also collaborating with a preservation project at Harvard University. This project will microfilm selected parts of astronomical Observatory reports. We plan to scan these microfilms to produce electronic images of these reports and put them on-line in the ADS. We hope to eventually cover most of the astronomical literature. In order to organize the scanned pages into articles, we need tables of contents (ToC). The early issues of the journals did not have printed ToC pages, so this needs to be done by hand. We do not have the financial resources to build these ToCs. We are looking for collaborators who would be willing to work with us in building these ToCs for the older journals and observatory reports. If you are interested in such a project, please contact the first author at gei@cfa.harvard.edu.
Directory of Open Access Journals (Sweden)
Dušanić Slobodan S.
2004-01-01
Full Text Available Both Roman generals and modern historians have tended to find Julian's moves in the civil war of AD 361 hazardous as well as difficult to understand. This is especially true of his long, ultra-rapid and semi-clandestine journey down the Danube, which was carried out by a dangerously small corps (under the command of the Usurper himself ! and ended with a very brief visit to Sirmium. A competent and, otherwise, cautious general, Julian must have had strong reasons for the risky haste that led him to Sirmium. These reasons were not primarily of a military nature, though enlistment of fresh troops and formation of vexillationes was among the measures he undertook/ initiated in the Pannonian metropolis. A (neglected passage (13. 287 a of his Letter to the Athenians (? mainly written during the river journey but sent from Sirmium itself implies that his visit to Sirmium was chiefly caused by his urgent need to secure the rich mines of precious metals managed by that city (mines situated in the Drinus valley and the Mt. Cer area, as well as silver and gold objects (coins, ingots, plates etc. stored in Sirmium, which had a mint and the metal officinae of its own. All this would help him i.a. distribute the donativa, already promised to his soldiers and officers. Analogous strategies, inspired by the old experience that the pecunia and/or metalla is/are nervus belli civilis, left traces in the sources describing the wars between Constantine I and Licinius, Vitellius and Vespasian, Otho and Vitellius — to cite the most illustrative examples only.
Ca2+ Regulation of Rabbit Skeletal Muscle Thin Filament Sliding: Role of Cross-Bridge Number
Liang, Bo; Chen, Ying; Wang, Chien-Kao; Luo, Zhaoxiong; Regnier, Michael; Gordon, Albert M.; Chase, P. Bryant
2003-01-01
We investigated how strong cross-bridge number affects sliding speed of regulated Ca2+-activated, thin filaments. First, using in vitro motility assays, sliding speed decreased nonlinearly with reduced density of heavy meromyosin (HMM) for regulated (and unregulated) F-actin at maximal Ca2+. Second, we varied the number of Ca2+-activatable troponin complexes at maximal Ca2+ using mixtures of recombinant rabbit skeletal troponin (WT sTn) and sTn containing sTnC(D27A,D63A), a mutant deficient i...
Light-cone AdS/CFT-adapted approach to AdS fields/currents, shadows, and conformal fields
Metsaev, R R
2015-01-01
Light-cone gauge formulation of fields in AdS space and conformal field theory in flat space adapted for the study of AdS/CFT correspondence is developed. Arbitrary spin mixed-symmetry fields in AdS space and arbitrary spin mixed-symmetry currents, shadows, and conformal fields in flat space are considered on an equal footing. For the massless and massive fields in AdS and the conformal fields in flat space, simple light-cone gauge actions leading to decoupled equations of motion are found. For the currents and shadows, simple expressions for all 2-point functions are also found. We demonstrate that representation of conformal algebra generators on space of currents, shadows, and conformal fields can be built in terms of spin operators entering the light-cone gauge formulation of AdS fields. This considerably simplifies the study of AdS/CFT correspondence. Light-cone gauge actions for totally symmetric arbitrary spin long conformal fields in flat space are presented. We apply our approach to the study of tota...
Protein domain organisation: adding order
Directory of Open Access Journals (Sweden)
Kummerfeld Sarah K
2009-01-01
Full Text Available Abstract Background Domains are the building blocks of proteins. During evolution, they have been duplicated, fused and recombined, to produce proteins with novel structures and functions. Structural and genome-scale studies have shown that pairs or groups of domains observed together in a protein are almost always found in only one N to C terminal order and are the result of a single recombination event that has been propagated by duplication of the multi-domain unit. Previous studies of domain organisation have used graph theory to represent the co-occurrence of domains within proteins. We build on this approach by adding directionality to the graphs and connecting nodes based on their relative order in the protein. Most of the time, the linear order of domains is conserved. However, using the directed graph representation we have identified non-linear features of domain organization that are over-represented in genomes. Recognising these patterns and unravelling how they have arisen may allow us to understand the functional relationships between domains and understand how the protein repertoire has evolved. Results We identify groups of domains that are not linearly conserved, but instead have been shuffled during evolution so that they occur in multiple different orders. We consider 192 genomes across all three kingdoms of life and use domain and protein annotation to understand their functional significance. To identify these features and assess their statistical significance, we represent the linear order of domains in proteins as a directed graph and apply graph theoretical methods. We describe two higher-order patterns of domain organisation: clusters and bi-directionally associated domain pairs and explore their functional importance and phylogenetic conservation. Conclusion Taking into account the order of domains, we have derived a novel picture of global protein organization. We found that all genomes have a higher than expected
Accessing the nuclear symmetry energy in Ca+Ca collisions
International Nuclear Information System (INIS)
The status of the analysis of the INDRA-VAMOS experiment performed at GANIL, using the reactions 40,48Ca+40,48Ca reactions at 35 AMeV, are presented. Isotopic distributions of fragments produced in multifragmentation events provide information on the importance of the surface term contribution in the symmetry energy by comparison to AMD predictions. (authors)
Effects of ad placement and type on consumer responses to podcast ads.
Ritter, Eric A; Cho, Chang-Hoan
2009-10-01
The purpose of this study was to understand the effects of podcast ad placement and podcast ad type on consumers' perceived intrusiveness, perceived irritation, attitude toward the ad, and ad avoidance. Our 2 x 2 (traditional ad vs. sponsorship by beginning vs. middle) experimental study found that sponsorships generated better consumer responses than did traditional ads and that podcast ads placed at the beginning of audio podcasts yielded better consumer responses than those placed in the middle. Implications for marketers and advertisers are discussed. PMID:19817565
From the generalized uncertainty relations on fuzzy AdS2 to the Poincare geometry
International Nuclear Information System (INIS)
The positive and discrete unitary irreps of SU(1,1) are used to construct fuzzy (Euclidean) AdS2. Two different types of uncertainty relation involving the Weyl-Heisenberg and a weaker type are studied. It is shown that there are no generalized coherent states which simultaneously minimize the Weyl-Heisenberg uncertainty relations among three non-commuting embedding coordinates of the fuzzy AdS2. However, generalized squeezed states that simultaneously satisfy the three weaker uncertainty relations do exist, and reproduce some properties of the classical AdS2. Up to a common scaling factor in terms of the irrep label, the expectation values of the non-commuting coordinates over such states are described in the same manner as the classical AdS2, in terms of the Poincare coordinates. The expectation values on the fuzzy AdS2 tend to their corresponding values in the commutative limit. (orig.)
A mosaic adenovirus possessing serotype Ad5 and serotype Ad3 knobs exhibits expanded tropism
International Nuclear Information System (INIS)
The efficiency of cancer gene therapy with recombinant adenoviruses based on serotype 5 (Ad5) has been limited partly because of variable, and often low, expression by human primary cancer cells of the primary cellular-receptor which recognizes the knob domain of the fiber protein, the coxsackie and adenovirus receptor (CAR). As a means of circumventing CAR deficiency, Ad vectors have been retargeted by utilizing chimeric fibers possessing knob domains of alternate Ad serotypes. We have reported that ovarian cancer cells possess a primary receptor for Ad3 to which the Ad3 knob binds independently of the CAR-Ad5 knob interaction. Furthermore, an Ad5-based chimeric vector, designated Ad5/3, containing a chimeric fiber proteins possessing the Ad3 knob, demonstrates CAR-independent tropism by virtue of targeting the Ad3 receptor. Based on these findings, we hypothesized that a mosaic virus possessing both the Ad5 knob and the Ad3 knob on the same virion could utilize either primary receptor, resulting in expanded tropism. In this study, we generated a dual-knob mosaic virus by coinfection of 293 cells with Ad5-based and Ad5/3-based vectors. Characterization of the resultant virions confirmed the incorporation of both Ad5 and Ad3 knobs in the same particle. Furthermore, this mosaic virus was able to utilize either receptor, CAR and the Ad3 receptor, for virus attachment to cells. Enhanced Ad infectivity with the mosaic virus was shown in a panel of cell lines, with receptor profiles ranging from CAR-dominant to Ad3 receptor-dominant. Thus, this mosaic virus strategy may offer the potential to improve Ad-based gene therapy approaches by infectivity enhancement and tropism expansion
AGRICULTURAL VALUE ADDED: PROSPECTS FOR NORTH DAKOTA
Lambert, David K.; Lim, Siew Hoon; Tweeten, Kathleen M.; Leistritz, F. Larry; Wilson, William W.; McKee, Gregory J.; Nganje, William E.; DeVuyst, Cheryl Sinn; Saxowsky, David M.
2006-01-01
Introduction: This report provides an overview of the important factors affecting investments in agricultural value-added ventures. The introductory section outlines current research on factors important in the location of economic activity. Research applied to specific agricultural value-added ventures, such as food manufacturing and livestock feeding and finishing operations, are discussed. A listing of resources available to entrepreneurs considering value-added investments concludes the i...
The heat resistance of a polyurethane coating filled with modified nano-CaCO3
Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei
2014-10-01
The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.
Zhang, Jia-Lin; Cai, Rong-Gen; Yu, Hongwei
2014-01-01
We study the thermodynamics and thermodynamic geometry of a five-dimensional Schwarzschild AdS black hole in AdS 5 × S 5 spacetime by treating the cosmological constant as the number of colors in the boundary gauge theory and its conjugate quantity as the associated chemical potential. It is found that the chemical potential is always negative in the stable branch of black hole thermodynamics and it has a chance to be positive, but appears in the unstable branch. We calculate the scalar curva...
Ad-Coop Positioning System (ACPS)
DEFF Research Database (Denmark)
Frattasi, Simone; Monti, Marco
2008-01-01
In this paper, we propose an innovative solution for positioning determination in 4G wireless networks by introducing the Ad-Coop Positioning System (ACPS). The ACPS is supported by a hybrid cellular ad-hoc architecture, where the cellular network has a centralized control over the ad......-hoc connections among pairs of mobiles. Specifically, peer-to-peer (P2P) communications are exploited in a mesh fashion within cellular-established clusters for cooperation-aided localization purposes (from that, the word ad-coop is derived). The major contribution of this work is the design of the data fusion...... conventional hybrid positioning techniques in cellular networks....
KOBAYASHI, Shigeki; Susa, Takehisa; Ishiguchi, Hironori; Myoren, Takeki; Murakami, Wakako; Kato, Takayoshi; Fukuda, Masakazu; Hino, Akihiro; Suetomi, Takeshi; Ono, Makoto; Uchinoumi, Hitoshi; Tateishi, Hiroki; Mochizuki, Mamoru; Oda, Tetsuro; Okuda, Shinichi
2015-01-01
Objectives The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. Background The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca2+ handling in heart failure remains unclear. Methods We investigated the effect of milrinone plus landiolol on intracellular Ca2+ transient (CaT), cell shortening (...
On shape dependence of holographic entanglement entropy in AdS4/CFT3
Fonda, Piermarco; Tonni, Erik
2015-01-01
We study the finite term of the holographic entanglement entropy of finite domains with smooth shapes and for four dimensional gravitational backgrounds. Analytic expressions depending on the unit vectors normal to the minimal area surface are obtained for both stationary and time dependent spacetimes. The special cases of AdS4, asymptotically AdS4 black holes, domain wall geometries and Vaidya-AdS backgrounds have been analysed explicitly. When the bulk spacetime is AdS4, the finite term is the Willmore energy of the minimal area surface viewed as a submanifold of the three dimensional flat Euclidean space. For the static spacetimes, some numerical checks involving spatial regions delimited by ellipses and non convex domains have been performed. In the case of AdS4, the infinite wedge has been also considered, recovering the known analytic formula for the coefficient of the logarithmic divergence.
Half BPS states in AdS5 x Yp,q
International Nuclear Information System (INIS)
We study a class of solutions of IIB supergravity which are asymptotically AdS5 x Yp,q. They have an R x SO(4) x SU(2) x U(1) isometry and preserve half of the 8 supercharges of the background geometry. They are described by a set of second order differential equations that we have found and analysed in a previous paper, where we studied 1/8 BPS states in the maximally supersymmetric AdS5 x S5 background. These geometries correspond to certain chiral primary operators of the N = 1 superconformal quiver theories, dual to IIB theory on AdS5 x Yp,q. We also show how to recover the AdS5 x Yp,q backgrounds by suitably doubling the number of preserved supersymmetries. We then solve the differential equations perturbatively in a large AdS5 radius expansion, imposing asymptotic AdS5 x Yp,q boundary conditions. We compute the global baryonic and mesonic charges, including the R-charge. As for the computation of the mass, i.e. the conformal dimension Δ of the dual field theory operators, which is notoriously subtle in asymptotically AdS backgrounds, we adopt the general formalism due to Wald and collaborators, which gives a finite result, and verify the relation Δ = 3R/2, demanded by the N = 1 superconformal algebra
Changes of inclusion, texture and magnetic property of non-oriented Si steel treated by Ca alloy
Lv, X.; Zhang, F.; Chen, X.
2015-04-01
Based on the industrial production of non-oriented Si steel, Ca treatment by Ca alloy adding during the RH refining process was studied. The changes of inclusion, crystal texture and microstructure, and its effect on magnetic properties of final steel sheets were analyzed. The results showed that, in present work, Ca treatment can improve the texture proportion of {110} and {111} significantly, and the formation of MnS and AlN inclusions were restrained. Meanwhile, the recrystallization effects of hot rolled strip get bad and the fiber structure enhanced obviously. The grain size of finished steel sheets increased as the increase of Ca alloy adding amount quickly, and then decreased. Compared with the non-Ca treatment charge, the numbers of inclusions whose size below 1.0μm will decrease by 68.06%, 87.50% and 94.94%, the texture proportion of {110} and {111} was 30.3%, 39.1%, 17.6% and 2.8%, 5.5%, 20.6%, while the correspondent Ca alloy adding amount is 0.67 kg/t steel, 1.00 kg/t steel and 1.67 kg/t steel, respectively. In addition, the core loss gradually decreases to a stable level as the increasing of Ca added, and the magnetic induction decreases quickly after slow increasing, respectively. The optimal Ca treatment mode depends on the chemical compositions of steel grades.
Mazhari, N S; Bahamonde, Sebastian; Faizal, Mir; Myrzakulov, Ratbay
2016-01-01
The holographic complexity and fidelity susceptibility have been defined as new quantities dual to different volumes in AdS. In this paper, we will use these new proposals to calculate both of these quantities for a variety of interesting deformations of AdS. We obtain the holographic complexity and fidelity susceptibility for an AdS black hole, Janus solution and a solution with cylindrically symmetry, an inhomogeneous background and a hyperscaling violating background. It is observed that the holographic complexity depends on the size of the subsystem for all these solutions and the fidelity susceptibility does not any such dependence.
Entropy of Warped Taub-NUT AdS Black String via the Brick Wall Method
Lee, Chong Oh
2014-01-01
When we consider five-dimensional warped Taub-NUT AdS black string with minimally coupled massive scalar field, we calculate an entropy by using the brick wall method. In extremely light effective mass, we find the entropy is proportional to an extra dimension wave number as well as quadratically divergent in a cutoff parameter. After taking zero NUT charge, we find the entropy of warped (AdS) Schwartzshield black hole string has a similar properties in as warped Taub-NUT AdS black string.
Geometric finiteness, holography and quasinormal modes for the warped AdS3 black hole
International Nuclear Information System (INIS)
We show that there exists a precise kinematical notion of holography for the Euclidean warped AdS3 black hole. This follows from the fact that the Euclidean warped AdS3 black hole spacetime is a geometrically finite hyperbolic manifold. For such manifolds a theorem of Sullivan provides a one-to-one correspondence between the hyperbolic structure in the bulk and the conformal structure of its boundary. Using this theorem we obtain the holographic quasinormal modes for the warped AdS3 black hole.
Discrete D-branes in AdS3 and in the 2d black hole
International Nuclear Information System (INIS)
I show how the AdS2 D-branes in the Euclidean AdS3 string theory are related to the continuous D-branes in Liouville theory. I then propose new discrete D-branes in the Euclidean AdS3 which correspond to the discrete D-branes in Liouville theory. These new D-branes satisfy the appropriate shift equations. They give rise to two families of discrete D-branes in the 2d black hole, which preserve di (registered) erent symmetries
Discrete D-branes in AdS3 and in the 2d black hole
Ribault, S
2006-01-01
I show how the AdS2 D-branes in the Euclidean AdS3 string theory are related to the continuous D-branes in Liouville theory. I then propose new discrete D-branes in the Euclidean AdS3 which correspond to the discrete D-branes in Liouville theory. These new D-branes satisfy the appropriate shift equations. They give rise to two families of discrete D-branes in the 2d black hole, which preserve different symmetries.
Discrete D-branes in AdS3 and in the 2d black hole
International Nuclear Information System (INIS)
I show how the AdS2 D-branes in the Euclidean AdS3 string theory are related to the continuous D-branes in Liouville theory. I then propose new discrete D-branes in the Euclidean AdS3 which correspond to the discrete D-branes in Liouville theory. These new D-branes satisfy the appropriate shift equations. They give rise to two families of discrete D-branes in the 2d black hole, which preserve different symmetries. (orig.)
Google Advertising Tools Cashing in with AdSense and AdWords
Davis, Harold
2010-01-01
With this book, you'll learn how to take full advantage of Google AdWords and AdSense, the sophisticated online advertising tools used by thousands of large and small businesses. This new edition provides a substantially updated guide to advertising on the Web, including how it works in general, and how Google's advertising programs in particular help you make money. You'll find everything you need to work with AdWords, which lets you generate text ads to accompany specific search term results, and AdSense, which automatically delivers precisely targeted text and image ads to your website.
On circular strings in $(AdS_3 \\times S^3)_{\\varkappa}$
Banerjee, Aritra
2016-01-01
The so called one-parameter (often called $\\varkappa$) deformed $AdS$ string sigma models have attracted a lot of attention lately in the study of integrability in string theory. We construct various circular string solutions in the $(AdS_3 \\times S^3)_{\\varkappa}$ background and describe the characteristics of such solutions qualitatively. We study the Bohr-Sommerfeld like quantization for these string states to characterise the motion. Further we find a `long' string limit of such circular strings in the $\\varkappa$-deformed $AdS_3$ and find a novel dependence of the oscillation number on the energy in the next to leading order expansion.
$ \\mathcal{N} $ = 4 supersymmetric Yang-Mills theories in AdS 3
Kuzenko, Sergei M.; Gabriele Tartaglino-Mazzucchelli(School of Physics M013, The University of Western Australia, 35 Stirling Highway, Crawley W.A. 6009, Australia)
2014-01-01
For all types of $ \\mathcal{N} $ = 4 anti-de Sitter (AdS) supersymmetry in three dimensions, we construct manifestly supersymmetric actions for Abelian vector multiplets and explain how to extend the construction to the non-Abelian case. Manifestly $ \\mathcal{N} $ = 4 supersymmetric Yang-Mills (SYM) actions are explicitly given in the cases of (2,2) and critical (4,0) AdS supersymmetries. The $ \\mathcal{N} $ = 4 vector multiplets and the corresponding actions are then reduced to (2,0) AdS sup...
Using Wikipedia categories for ad hoc search
R. Kaptein; M. Koolen; J. Kamps
2009-01-01
In this paper we explore the use of category information for ad hoc retrieval in Wikipedia. We show that techniques for entity ranking exploiting this category information can also be applied to ad hoc topics and lead to significant improvements. Automatically assigned target categories are good sur
Reductio ad Contradictionem: An Algebraic Perspective
Czech Academy of Sciences Publication Activity Database
Přenosil, Adam
2016-01-01
Roč. 104, č. 3 (2016), s. 389-415. ISSN 0039-3215 R&D Projects: GA ČR GAP202/10/1826 Institutional support: RVO:67985807 Keywords : de Morgan algebras * contradiction * reductio ad contradictionem * reductio ad absurdum * four-valued logic * paraconsistent logic * inconsistency * completeness Subject RIV: BA - General Mathematics Impact factor: 0.598, year: 2014
Value added meat marketing around the globe
DEFF Research Database (Denmark)
Grebitus, Carola; Mueller Loose, Simone
In highly competitive meat markets it is important to offer value added products to consumers. Thus, we need to understand which attributes are especially valued by consumers. This track session will contribute to a better understanding of consumer preferences for value added meats across different...
The concept of added value of FM
DEFF Research Database (Denmark)
Jensen, Per Anker; van der Voordt, Theo; Coenen, Christian;
2012-01-01
. The included journals were analysed over a time period of ten years, with a focus on interesting topics and less on a thematic cross-paper analysis in-depth. Originality/value: Usually the concept of added value is discussed from a mono-disciplinary point of view. The different backgrounds of the authors add......Purpose: This chapter presents research perspectives and theoretical reflections on the concept of added value of FM from a variety of academic fields. Methodology: A literature review of the most influential journals within the academic fields of Facilities Management (FM), Corporate Real Estate...... conceptualization of the concept of added value of FM is of utmost importance for further research into the added value of FM and well-considered, evidence- based Value Adding Management in practice. Research limitations: Due to limited time not all FM-related journals could be included in the literature review...
Energy Technology Data Exchange (ETDEWEB)
Freivogel, Ben; /Stanford U., Phys. Dept. /LBL, Berkeley; Hubeny, Veronika E.; /LBL, Berkeley /Durham U., Dept. of Math.; Maloney, Alexander; /Stanford U., Phys. Dept.; Myers, Rob; /Perimeter Inst. Theor. Phys. /Waterloo U.; Rangamani, Mukund; /LBL, Berkeley /Durham U., Dept. of Math.; Shenker, Stephen; /Stanford U., Phys. Dept.
2005-10-07
We study the realization of inflation within the AdS/CFT correspondence. We assume the existence of a string landscape containing at least one stable AdS vacuum and a (nearby) metastable de Sitter state. Standard arguments imply that the bulk physics in the vicinity of the AdS minimum is described by a boundary CFT. We argue that large enough bubbles of the dS phase, including those able to inflate, are described by mixed states in the CFT. Inflating degrees of freedom are traced over and do not appear explicitly in the boundary description. They nevertheless leave a distinct imprint on the mixed state. Analytic continuation allows us, in principle, to recover a large amount of nonperturbatively defined information about the inflating regime. Our work also shows that no scattering process can create an inflating region, even by quantum tunneling, since a pure state can never evolve into a mixed state under unitary evolution.We study the realization of inflation within the AdS/CFT correspondence. We assume the existence of a string landscape containing at least one stable AdS vacuum and a (nearby) metastable de Sitter state. Standard arguments imply that the bulk physics in the vicinity of the AdS minimum is described by a boundary CFT. We argue that large enough bubbles of the dS phase, including those able to inflate, are described by mixed states in the CFT. Inflating degrees of freedom are traced over and do not appear explicitly in the boundary description. They nevertheless leave a distinct imprint on the mixed state. Analytic continuation allows us, in principle, to recover a large amount of nonperturbatively defined information about the inflating regime. Our work also shows that no scattering process can create an inflating region, even by quantum tunneling, since a pure state can never evolve into a mixed state under unitary evolution.
New pyrometallurgical process of EAF dust treatment with CaO addition
Institute of Scientific and Technical Information of China (English)
Romchat Chairaksa-Fujimoto; Yosuke Inoue; Naoyoshi Umeda; Satoshi Itoh; Tetsuya Nagasaka
2015-01-01
The non-carbothermic zinc pyrometallurgical processing of electric arc furnace (EAF) dust was investigated on a laboratory scale. The main objective of this process was to convert highly stable zinc ferrite (ZnFe2O4), which accounts for more than half of total zinc in the EAF dust, into ZnO and Ca2Fe2O5 by CaO addition. The EAF dust was mixed with CaO powder in various ratios, pressed into pellets, and heated in a muffle furnace in air at temperatures ranging from 700 to 1100°C for a predetermined holding time. All ZnFe2O4 was transformed into ZnO and Ca2Fe2O5 at a minimum temperature of 900°C within 1 h when sufficient CaO to achieve a Ca/Fe molar ratio of 1.1 was added. However, at higher temperatures, excess CaO beyond the stoichiometric ratio was required because it was consumed by reactions leading to the formation of compounds other than ZnFe2O4. The evaporation of halides and heavy metals in the EAF dust was also studied. These components could be pref-erentially volatilized into the gas phase at 1100°C when CaO was added.
Production of CaSO4:Dy thermoluminescence dosimeters from natural crystals of Iran
International Nuclear Information System (INIS)
Calcium sulphate (CaSO4:Dy) thermoluminescence (TL) phosphors were produced from natural CaSO4:2H2O crystals of Iran for large-scale dosimetry. The procedure of recrystallization of the natural crystals was followed. A known amount of Dy2O3 was added into diluted H2SO4 as dopant at 200 degree C. Also a known amount of CaSO4:2H2O powder was added to the solution heated up to final recrystallization stage. Different parameters such as washing of the crystal powder for sodium (Na) removal, Dy2O3 incorporation and oven-heating temperature were optimized. The TLD phosphor produced has a sensitivity over 1.3 times higher than that of Harshaw CaSO4:Dy phosphors. The results are presented and discussed. (7 figs.)
International Nuclear Information System (INIS)
We hypothesized that assessment of myocardial sympathetic activity with no-carrier-added (nca) 123I-meta-iodobenzylguanidine (MIBG) compared to carrier-added (ca) 123I-MIBG would lead to an improvement of clinical performance without major differences in radiation dosimetry. In nine healthy volunteers, 15 min and 4 h planar thoracic scintigrams and conjugate whole-body scans were performed up to 48 h following intravenous injection of 185 MBq 123I-MIBG. The subjects were given both nca and ca 123I-MIBG. Early heart/mediastinal ratios (H/M), late H/M ratios and myocardial washout were calculated. The fraction of administered activity in ten source organs was quantified from the attenuation-corrected geometric mean counts in conjugate views. Radiation-absorbed doses were estimated with OLINDA/EXM software. Both early and late H/M were higher for nca 123I-MIBG (ca 123I-MIBG early H/M 2.46 ± 0.15 vs nca 123I-MIBG 2.84 ± 0.15, p 0.001 and ca 123I-MIBG late H/M 2.69 ± 0.14 vs nca 123I-MIBG 3.34 ± 0.18, p = 0.002). Myocardial washout showed a longer retention time for nca 123I-MIBG (p 123I-MIBG was similar to that for ca 123I-MIBG (0.025 ± 0.002 mSv/MBq vs 0.026 ± 0.002 mSv/MBq, p = 0.055, respectively). No-carrier-added 123I-MIBG yields a higher relative myocardial uptake and is associated with a higher myocardial retention. This difference between nca 123I-MIBG and ca 123I-MIBG in myocardial uptake did not result in major differences in estimated absorbed doses. Therefore, nca 123I-MIBG is to be preferred over ca 123I-MIBG for the assessment of cardiac sympathetic activity. (orig.)
Institute of Scientific and Technical Information of China (English)
YANG Mingbo; CHENG Liang; SHEN Jia; PAN Fusheng
2009-01-01
The effect of Ca addition on the as-cast microstructure and creep properties of Mg-5Zn-5Sn magnesium alloy was investigated. The results indicate that adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy can effectively refine the as-cast microstructure of the alloy, and the CaMgSn phase with high thermal stability is formed in the alloy. In addition, adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy can also improve the creep properties of the alloy. After adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy, the second creep rate of the alloy at 150℃ and 50 MPa for 100 h decreases from 4.67×10~(-8) to 1.43×10~(-8) s~(-1). The strengthening mechanism is mainly attributed to the microstructural refinement and the formation of CaMgSn phase.
Comments Concerning the CFT Description of Small Objects in AdS
Hubeny, V.; Susskind, L.; Toumbas, N.
2000-01-01
In this paper we resolve a contradiction posed in a recent paper by Horowitz and Hubeny. The contradiction concerns the way small objects in AdS space are described in the holographic dual CFT description.
A Grassmann Path From AdS$_3$ to Flat Space
Krishnan, Chethan; Roy, Shubho
2013-01-01
We show that interpreting the inverse AdS$_3$ radius $1/l$ as a Grassmann variable results in a formal map from gravity in AdS$_3$ to gravity in flat space. The underlying reason for this is the fact that $ISO(2,1)$ is the Inonu-Wigner contraction of $SO(2,2)$. We show how this works for the Chern-Simons actions, demonstrate how the general (Banados) solution in AdS$_3$ maps to the general flat space solution, and how the Killing vectors, charges and the Virasoro algebra in the Brown-Henneaux case map to the corresponding quantities in the BMS$_3$ case. Our results straightforwardly generalize to the higher spin case: the recently constructed flat space higher spin theories emerge automatically in this approach from their AdS counterparts. We conclude with a discussion of singularity resolution in the BMS gauge as an application.
Two gravitational shock waves on the AdS3 brane
International Nuclear Information System (INIS)
A gravitational shock wave is a solution to Einstein equations describing the gravitational field of a massless particle. We obtain such a geometry for a particle moving on a AdS3 brane embedded in a AdS4 bulk (the lower dimensional version of the ''locally localized gravity'' model of Karch and Randall). In order to do this, we use two different techniques. First, we solve directly Einstein equations sourced by a massless particle. Then we boost to the speed of light the AdS3 brane black hole solution of Emparan et al. while sending its mass parameter to zero. Surprisingly, we obtain two different results. We discuss the origin of these two different solutions both in the bulk and in the CFT picture. As a by-product, we derive the expression for the shock wave associated to a transversally accelerating particle in AdS4
Boundary three-point function on AdS2 D-branes
International Nuclear Information System (INIS)
Using the H3+-Liouville relation, I explicitly compute the boundary three-point function on AdS2 D-branes in H3+, and check that it exhibits the expected symmetry properties and has the correct geometrical limit. I then find a simple relation between this boundary three-point function and certain fusing matrix elements, which suggests a formal correspondence between the AdS2 D-branes and discrete representations of the symmetry group. Concluding speculations deal with the fuzzy geometry of AdS2 D-branes, strings in the Minkowskian AdS3, and the hypothetical existence of new D-branes in H3+
Boundary three-point function on AdS2 D-branes
Ribault, Sylvain
2008-01-01
Using the H3+-Liouville relation, I explicitly compute the boundary three-point function on AdS2 D-branes in H3+, and check that it exhibits the expected symmetry properties and has the correct geometrical limit. I then find a simple relation between this boundary three-point function and certain fusing matrix elements, which suggests a formal correspondence between the AdS2 D-branes and discrete representations of the symmetry group. Concluding speculations deal with the fuzzy geometry of AdS2 D-branes, strings in the Minkowskian AdS3, and the hypothetical existence of new D-branes in H3+.
Impaired cognition in depression and Alzheimer (AD: a gradient from depression to depression in AD
Directory of Open Access Journals (Sweden)
Narahyana Bom de Araujo
2014-09-01
Full Text Available Objective To assess cognition in major depressed (MD, Alzheimer's disease (AD, and depression in AD elderly. Method Subjects were evaluated by Mini Mental, Rey Auditory Verbal Learning Test, Rey Complex Figure, Digit Span, Similarities, Trail Making A/B, Verbal Fluency and Stroop. One-way ANOVA and multivariate models were used to compare the performance of each group on neuropsychological tests. Results We evaluated 212 subjects. Compared to MD, attention, working memory, processing speed and recall showed significantly better in controls. Controls showed significantly higher performance in all cognitive measures, except in attention compared to AD. Verbal fluency, memory, processing speed and abstract reasoning in MD was significantly higher compared to AD. AD was significantly better in general cognitive state than depression in AD. All other cognitive domains were similar. Conclusion A decreasing gradient in cognition appeared from the control to depression in AD, with MD and AD in an intermediate position.
CaPTC hosts the 'Biennial Science of Global Prostate Cancer Disparities in Black Men' conference to address the growing global public health problem of prostate cancer among Black men in industrialized and developing countries.
National Oceanic and Atmospheric Administration, Department of Commerce — Sonoma County Vegetation Mapping and LiDAR Consortium retained WSI to provide lidar and Orthophoto data and derived products in Sonoma County, CA. A classified LAS...
International Nuclear Information System (INIS)
CaWave User's Guide explains how to use the CaWave functions which were specifically written in PV-WAVE command language and C language for EPICS users. CaWave consists of a special set of external channel access functions which provides the PV-WAVE users with easy and flexible access of channel information across the IOC networks. It also provides a complete set of process variable event monitoring functions. This document also gives examples how a PV-WAVE user can interface to channel access devices. It is assumed that the user is already familiar with using PV-WAVE. Few simple example modules of using PV-WAVE command language with CaWave functions are also given in this document
Separation of no-carrier-added 66,67Ga from bulk cobalt by a biopolymer
International Nuclear Information System (INIS)
Heavy ion activation of natural cobalt foil with 80.5MeV 12C results in the formation of no-carrier-added 66,67As radionuclides, along with their corresponding decay products, 66,67Ge and 66,67Ga in the matrix. Attempt has been made to separate the no-carrier-added gallium radionuclides from the target matrix cobalt using a biopolymer, Fe doped calcium alginate (Fe-CA) beads. A complete separation was achieved by adsorbing 66,67Ga and lesser amount of bulk Co at pH3 followed by washing the beads with 0.4M NaNO. (author)
CA 242, a new tumour marker for pancreatic cancer: a comparison with CA 19-9, CA 50 and CEA.
Haglund, C.; Lundin, J; Kuusela, P.; Roberts, P. J.
1994-01-01
The serum expression of a novel tumour marker, CA 242, defined by monoclonal antibody C 242, was studied in 179 patients with pancreatic cancer. The results were compared with CA 19-9, CA 50 and CEA. CA 242 is a carbohydrate closely related, but not identical, to CA 19-9 and CA 50. The overall sensitivity of the CA 242 assay was 74%: 55% in stage I, 83% in stage II-III and 78% in stage IV disease. The specificity calculated from 112 patients with benign diseases was 91%. CA 19-9 had a higher ...
On Critical Massive (Super)Gravity in adS3
Bergshoeff, Eric A; Rosseel, Jan; Sezgin, Ergin; Townsend, Paul K
2010-01-01
We review the status of three-dimensional "general massive gravity" (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of "chiral gravity". We then show how these results extend to N=1 super-GMG, expanded about a supersymmetric adS vacuum, and also to the most general `curvature-squared' N=1 supergravity model.
On Critical Massive (Super)Gravity in adS3
International Nuclear Information System (INIS)
We review the status of three-dimensional 'general massive gravity' (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of chiral gravity. We then show how these results extend to super-GMG, expanded about a supersymmetric adS vacuum, and also to the most general 'curvature-squared' supergravity model.
On the gauge dependence of the AdS instability problem
Dimitrakopoulos, Fotios V; Pedraza, Juan F; Yang, I-Sheng
2016-01-01
Previous work on the AdS instability problem within the two-time framework (TTF) has found an "oscillating singularity" whose presence depends on the gauge choice. We give a physical interpretation of this singularity as a diverging redshift between the boundary and the center of AdS. This signals a genuine breakdown of the linearized gravity. One can also identify the diverging redshift through a back-reaction calculation purely in the boundary gauge, where the TTF result stays regular.
Supergravity background of the lambda-deformed AdS_3 x S^3 supercoset
Chervonyi, Yuri
2016-01-01
We construct the solution of type IIB supergravity describing the integrable lambda-deformation of the AdS_3 x S^3 supercoset. While the geometry corresponding to the deformation of the bosonic coset has been found in the past, our background is more natural for studying superstrings, and several interesting features distinguish our solution from its bosonic counterpart. We also report progress towards constructing the lambda-deformation of the AdS_5 x S^5 supercoset.
Yangian of AdS_3/CFT_2 and its deformation
Regelskis, Vidas
2015-01-01
We construct highest-weight modules and a Yangian extension of the centrally extended superalgebra appearing in the worldsheet scattering associated with the AdS_3 /CFT_2 duality, and show a link to the Yangian of AdS_5/CFT_4. We also consider a quantum deformation of this superalgebra, its modules and a quantum affine extension of the Drinfeld-Jimbo type which describes deformed worldsheet scattering.
Decomposition Reaction of Mixed Rare Earth Concentrate and Roasted with CaO and NaCl
Institute of Scientific and Technical Information of China (English)
Wu Wenyuan; Hu Guangyong; Sun Shuchen; Chen Xudong; Tu Ganfeng
2004-01-01
The reaction of the mixed rare earth concentrate including monazite ( REPO4 ) and bastnaesite ( REFCO3 )decomposed by CaO and NaCl additives at the temperature range from 100 to 1000 ℃ was studied by means of XRD and TG-DTA.The results show that when CaO and NaCl are not added, only REFCO3 can be decomposed at the temperature of 377 ～ 450 ℃.The decomposition products include REOF, RE2O3 and CeO2.However, REFCO3 can not be decomposed.When CaO is added, the decomposition reactions occur at the temperature range from 660 to 750 ℃.CaO has three decomposition functions: ( 1 ) REPO4 can be decomposed by CaO and the decomposition products include RE2O3 and Ca3 (PO4)2; (2) CaO can decompose REOF, and the decomposition products are RE2O3 and CaF2; (3)CaO can decompose REPO4 with CaF2, and the decomposition products are RE2 O3, Ca5 F( PO4 )3.The decomposition ratio of the mixed rare earth concentrate increased obviously, when CaO and NaC1 were added.NaC1 can supply the liquid for the reaction, improve the mass transfer process and accelerate the reaction.At the same time, NaC1 participated in the reaction that REPO4 was decomposed by CaO.
Ads/CFT correspondence and symmetry breaking
International Nuclear Information System (INIS)
We study, using the dual AdS description, the vacua of field theories where some of the gauge symmetry is broken by expectation values of scalar fields. In such vacua, operators built out of the scalar fields acquire expectation values, and we show how to calculate them from the behavior of perturbations to the AdS background near the boundary. Specific examples include the N = 4 SYM theory, and theories on D3-branes placed on orbifolds and conifolds. We also clarify some subtleties of the AdS/CFT correspondence that arise in this analysis. In particular, we explain how scalar fields in AdS space of sufficiently negative mass-squared can be associated with CFT operators of two possible dimensions. All dimensions are bounded from below by (d-2)/2; this is the unitarity bound for scalar operators in d-dimensional field theory. We further argue that the generating functional for correlators in the theory with one choice of operator dimension is a Legendre transform of the generating functional in the theory with the other choice
Study of ADS-B Data Evaluation
Institute of Scientific and Technical Information of China (English)
ZHANG Jun; LIU Wei; ZHU Yanbo
2011-01-01
In western China,the terrain and meteorological conditions are so complex that it is not suitable to construct new radar stations.Automatic dependent surveillance-broadcast(ADS-B) is a totally new surveillance method,so before practically applied and operated in China,abundant tests and evaluations are necessary to validate the performance of ADS-B and guarantee the operational security.During the flight tests,we collect the data of radar,ADS-B and high accuracy position and compare the performance of ADS-B with radar based on high accuracy position.To solve the asynchronous problem among radar data,ADS-B data and real-time kinematic(RTK) data caused by different update rates,this article proposes the technique of synchronizing multi-surveil- lance data by extrapolating from the data of low update rate to high update rate according to velocity and heading.Meanwhile,because radar data,ADS-B data and RTK data are expressed in different coordinates and cannot be compared each other,this article provides a method to unifying the coordinates of multi-surveillance data.By the analysis and evaluation,we can conclude that the performance of ADS-B is better than radar.
Absorption of /sup 45/Ca during the immersion of the aerial organs of Salicornia stricta
Energy Technology Data Exchange (ETDEWEB)
Langlois, J.; Vilquin, A.
1971-04-01
Immersion of the aerial organs of Salicornia stricta in a nutrient solution with added radioactive /sup 45/Ca resulted in the accumulation of /sup 45/Ca in the aerial organs. There was no accumulation when the roots were immersed in the nutrient solution. Absorption of minerals by the stems and leaves of Salicornia during periodic submersions in the brackish water surrounding the plants, is therefore possible. 17 references, 1 figure, 1 table.
Half BPS states in AdS_5 x Y^{p,q}
Gava, Edi; Milanesi, Giuseppe; O'Loughlin, Martin
2008-01-01
We study a class of solutions of IIB Supergravity which are asymptotically AdS_5 x Y^{p,q}. They have an R x SO(4) x SU(2) x U(1) isometry and preserve half of the 8 supercharges of the background geometry. They are described by a set of second order differential equations that we have found and analysed in a previous paper, where we studied 1/8 BPS states in the maximally supersymmetric AdS_5 x S^5 background. These geometries correspond to certain chiral primary operators of the N=1 superconformal quiver theories, dual to IIB theory on AdS_5 x Y^{p,q}. We also show how to recover the AdS_5 x Y^{p,q} backgrounds by suitably doubling the number of preserved supersymmetries. We then solve the differential equations perturbatively in a large AdS_5 radius expansion, imposing asymptotic AdS_5 x Y^{p,q} boundary conditions. We compute the global baryonic and mesonic charges, including the R-charge. As for the computation of the mass, i.e. the conformal dimension D of the dual field theory operators, which is notor...
Research on ADS in Vinca Institute
International Nuclear Information System (INIS)
New project in the Vinca Institute for design an ADS is suggested to Ministry of science for support. This paper shows initial results of neutronic analyses, carried out by MCNP and SHIELD codes, on possible usage of a neutron source obtained from the lead target bombarded by beam of deuterons or protons, extracted from the VINCY cyclotron of the TESLA accelerator. It is confirmed that such low-flux ADS with HEU fuel, moderated by light water in squared lattice within lead matrix, can simulate some of characteristics of few proposed, well known, fast neutron spectrum, lead moderated and cooled, high-power energy sub-critical ADS. (author)
Open string fluctuations in AdS space with and without torsion
DEFF Research Database (Denmark)
Larsen, A.L.; Lomholt, Michael Andersen
2003-01-01
dangerous than expected in these cases. The general formalism can be straightforwardly used also to study the (bosonic part of the) fluctuations around the closed strings, recently considered in connection with the AdS/conformal field theory duality, on AdS ×S and AdS ×S ×T . © 2003 The American Physical......The equations of motion and boundary conditions for the fluctuations around a classical open string, in a curved space-time with torsion, are considered in compact and world-sheet covariant form. The rigidly rotating open strings in anti-de Sitter space with and without torsion are investigated in...
String in AdS Black Hole: A Thermo Field Dynamic Approach
Cantcheff, M. Botta; Gadelha, Alexandre L.; Marchioro, Dafni F. Z.; Nedel, Daniel Luiz
2012-01-01
Based on Maldacena's description of an eternal AdS-black hole, we reassess the Thermo Field Dynamics (TFD) formalism in the context of the AdS/CFT correspondence. The model studied here involves the maximally extended AdS-Schwarschild solution and two (non-interacting) copies of the CFT associated to the global AdS spacetime, along with an extension of the string by imposing natural gluing conditions in the horizon. We show that the gluing conditions in the horizon define a string boundary st...
Heat kernels on cone of AdS2 and k-wound circular Wilson loop in AdS5 × S5 superstring
Bergamin, R.; Tseytlin, A. A.
2016-04-01
We compute the one-loop world-sheet correction to partition function of {{AdS}}5× {{{S}}}5 superstring that should be representing k-fundamental circular Wilson loop in planar limit. The 2d metric of the minimal surface ending on k-wound circle at the boundary is that of a cone of AdS2 with deficit 2π (1-k). We compute the determinants of 2d fluctuation operators by first constructing heat kernels of scalar and spinor Laplacians on the cone using the Sommerfeld formula. The final expression for the k-dependent part of the one-loop correction has simple integral representation but is different from earlier results.
Zhang, Jia-Lin; Yu, Hongwei
2014-01-01
We study thermodynamics and thermodynamic geometry of a five-dimensional Schwarzschild AdS black hole in $AdS_5\\times{S^5}$ spacetime by treating the cosmological constant as the number of colors in the boundary gauge theory and its conjugate quantity as the associated chemical potential. It is found that the chemical potential is always negative in the stable branch of black hole thermodynamics and it has a chance to be positive, but appears in the unstable branch. We calculate scalar curvatures of the thermodynamical Weinhold metric, Ruppeiner metric and Quevedo metric, respectively and we find that the divergence of scalar curvature is related to the divergence of specific heat with fixed chemical potential in the Weinhold metric and Ruppeiner metric, while in the Quevedo metric the divergence of scalar curvature is related to the divergence of specific heat with fixed number of colors and the vanishing of the specific heat with fixed chemical potential.
Women May Need Added Therapy for Rosacea
... Grants for Rosacea Research Women May Need Added Therapy Rosacea can be a trying condition under the best ... or recommend any particular medications, products, equipment or treatments. Rosacea may vary substantially from one patient to another, ...
A guide to gauging ad effectiveness.
Cashill, J
1987-09-01
Techniques that have proven successful in private industry can help hospital executives increase their accountability for advertising expenditures. Among these techniques are: The random telephone survey, which can be used to measure whether the hospital's awareness level among the public has increased as the result of a particular ad; The focus group, which assists the hospital in evaluating how it is perceived in relation to other hospitals in its market; The pretest, to determine which ads to eliminate from a campaign and which ones to refine; Educational seminars and direct-response ads; Reliable baseline data on patients and services for use in comparing figures before and after an ad has been used. Above all, careful planning is required to enable the marketing staff to determine what it wishes to accomplish through advertising and to set measurable goals that reflect its expectations for each component of a campaign. PMID:10283482
Bergamin, R
2015-01-01
We compute the one-loop world-sheet correction to partition function of $AdS_5 \\times S^5$ superstring that should be representing $k$-fundamental circular Wilson loop in planar limit. The 2d metric of the minimal surface ending on $k$-wound circle at the boundary is that of a cone of $AdS_2$ with deficit $2\\pi (1-k)$. We compute determinants of 2d fluctuation operators by first constructing heat kernels of scalar and spinor Laplacians on the cone using the Sommerfeld formula. The final expression for the k-dependent part of the one-loop correction has simple integral representation but is different from earlier results.
Microbial production of value-added nutraceuticals.
Wang, Jian; Guleria, Sanjay; Koffas, Mattheos Ag; Yan, Yajun
2016-02-01
Nutraceuticals are important natural bioactive compounds that confer health-promoting and medical benefits to humans. Globally growing demands for value-added nutraceuticals for prevention and treatment of human diseases have rendered nutraceuticals a multi-billion dollar market. However, supply limitations and extraction difficulties from natural sources such as plants, animals or fungi, restrict the large-scale use of nutraceuticals. Metabolic engineering via microbial production platforms has been advanced as an eco-friendly alternative approach for production of value-added nutraceuticals from simple carbon sources. Microbial platforms like the most widely used Escherichia coli and Saccharomyces cerevisiae have been engineered as versatile cell factories for production of diverse and complex value-added chemicals such as phytochemicals, prebiotics, polysaccaharides and poly amino acids. This review highlights the recent progresses in biological production of value-added nutraceuticals via metabolic engineering approaches. PMID:26716360
Genes Might Explain Hispanics' Added Longevity
... page: https://medlineplus.gov/news/fullstory_160528.html Genes Might Explain Hispanics' Added Longevity Differences in 'genetic ... Services, or federal policy. More Health News on: Genes and Gene Therapy Hispanic American Health Recent Health ...
Underweight Seniors May Have Added Alzheimer's Risk
... fullstory_160278.html Underweight Seniors May Have Added Alzheimer's Risk Study links lower body weight to increased ... older adults' risk of the memory-robbing disorder Alzheimer's disease, new research suggests. The study included 280 ...
Optimizing Ad Allocation in Social Advertising
Tang, Shaojie; Yuan, Jing
2015-01-01
Social advertising (or social promotion) is an effective approach that produces a significant cascade of adoption through influence in the online social networks. The goal of this work is to optimize the ad allocation from the platform's perspective. On the one hand, the platform would like to maximize revenue earned from each advertiser by exposing their ads to as many people as possible, one the other hand, the platform wants to reduce free-riding to ensure the truthfulness of the advertise...
Selbstorganisierende Systemarchitekturen - Ad-hoc-Netze
Rabel, Matthias Reinhard
2007-01-01
A new in-vehicle network is developed and elaborated. The new protocol hierarchy aims at an ad hoc integration of typical in-vehicle networks, like CAN, IEEE 1394 and others. Therefore several communication protocols are developed. First an overall communication scheme needs to be available to allow end-to-end communication. This is done similar to OSI Layer 5, as session based communication. Sessions allow transitive communication paths without interruption. With this, an ad hoc behavior of ...
Security Threats in Mobile Ad Hoc Network
Biswas, Kamanashis; Ali, Md. Liakat
2007-01-01
Mobile Ad Hoc Network (MANET) is a collection of communication devices or nodes that wish to communicate without any fixed infrastructure and pre-determined organization of available links. The nodes in MANET themselves are responsible for dynamically discovering other nodes to communicate. Although the ongoing trend is to adopt ad hoc networks for commercial uses due to their certain unique properties, the main challenge is the vulnerability to security attacks. A number of challenges like o...
Massive Gravity in Ads and Minkowski Backgrounds
Porrati, M.
2004-01-01
I review some interesting features of massive gravity in two maximally symmetric backgrounds: Anti de Sitter space and Minkowski space. While massive gravity in AdS can be seen as a spontaneously broken, UV safe theory, no such interpretation exists yet in the flat-space case. Here, I point out the problems encountered in trying to find such completion, and possible mechanisms to overcome them.
Narayanan, Sathya; Byun, YoungJoon; Cebrowski Institute; CSUMB, C.S.I.T. Program
2011-01-01
In conjunction with the NPS C.S. Department MWC Group, this research looks at establishing an Ad Hoc Peer-to-Peer network on cell phones, specifically using the Android OS. Work comprised of Android Device, Library, and Application Design. The Library used was AODV (Ad Hoc on demand Distance Vector) and hardware devices must be controlled directly in addition to application enhancements. A prototype has been created and communication was achieved. Future work to include enhancements to contro...
International Trade Effects of Value Added Taxation
Paul Krugman; Martin Feldstein
1989-01-01
The actual value added tax systems used in many countries differ significantly from the completely general VAT that has been the focus of most economic analyses. In practice, VAT systems exempt broad classes of consumer goods and services. This has important implications for the effect of the VAT on international trade. A value added tax is sometimes advocated as a way of improving a country's international competitiveness because GATT rules permit the tax to be levied on imports and rebated ...
Competition in Unit vs. Ad Valorem Taxes
Ben Lockwood
2004-01-01
This paper shows that in a standard model of tax competition, the Nash equilibrium in capital taxes depends on whether these taxes are unit (as assumed in the literature) or ad valorem (as in reality). In a symmetric version of the model, general results are established: taxes and public good provision are both higher, and residents in all countries are better off, when countries compete in unit taxes, as opposed to ad valorem taxes. However, the difference in equilibrium outcomes is negligib...
Adding stress plot function to NASTRAN
Katoh, S.
1978-01-01
Stress plot function was developed and added to the NASTRAN level 15.5. Computed stress distribution can be displayed by this function, with vectors showing the principal stresses of the finite elements over the specified portions of the structure. NASTRAN is reviewed in the aspect of plotting capabilities. Stress tensor field is examined in preparation of stress display. Then the stress plot function as added to the NASTRAN is described. A sample plotout by this function is shown.
Classical Klein-Gordon solutions, symplectic structures and isometry actions on AdS spacetimes
Dohse, Max
2012-01-01
We study classical, real Klein-Gordon theory on Lorentzian Anti de Sitter ($\\AdS d$) spacetimes with spatial dimension $d$. We give a complete list of well defined and bounded Klein-Gordon solutions for three types of regions on AdS: slice (time interval times all of space), rod hypercylinder (all of time times solid ball in space), and tube hypercylinder (all of time times solid shell in space). Hypercylinder regions are of natural interest for AdS since the neighborhood of the AdS-boundary is a tube. For the solution spaces of our regions we find the actions induced by the AdS isometry group $\\SOgroup{2,d}$. For all three regions we find one-to-one correspondences between initial data and solutions on the regions. For rod and tube regions this initial data can also be given on the AdS boundary. We calculate symplectic structures associated to the solution spaces, and show their invariance under the isometry actions. We compare our results to the corresponding expressions for $(3\\pn1)$-dimensional Minkowski ...
AdS-Sliced Flavor Branes and Adding Flavor to the Janus Solution
Clark, Adam B; Newman, George M; Rommal, Andrea
2014-01-01
We implement D7 flavor branes in AdS-sliced coordinates on $AdS_5\\times S^5$ with the ansatz that the brane fluctuates only in the warped ($\\mu$) direction in this slicing, which is particularly appropriate for studying the Janus solution. The natural field theory dual in this slicing is $\\mathcal{N}=4$ super Yang-Mills on two copies of $AdS_4$. Branes extending from $\\mu=\\pm\\pi/2$ can end at different locations, giving rise to quarks with piecewise constant mass on each $AdS_4$ half-space, jumping discontinuously between them. A second class of flavor brane solutions exists in this coordinate system, dubbed "continuous" flavor branes, that extend across the entire range of $\\mu$. We propose that the correct dual interpretation of "disconnected" flavor brane in this ansatz is a quark hypermultiplet with constant mass on one of the AdS$_4$ half-spaces with totally reflecting boundary conditions at the boundary of AdS$_4$; whereas the dual interpretation of a continuous flavor brane has totally transparent boun...
Gauge Symmetries and Holographic Anomalies of Chern-Simons and Transgression AdS Gravity
Mora, Pablo
2014-01-01
We review the issue of gauge and gravitational anomalies with backgrounds, maybe offering a new outlook on some aspects of these questions. We compute the holographic anomalies of hypothetical theories dual, in the sense of the AdS-CFT correspondence, to Chern-Simons AdS gravities. Those anomalies are either gauge anomalies associated to the AdS gauge group of the theory or diffeomorphism anomalies, with each kind related to the other. As a result of using suitable action principles por Chern-Simons AdS gravities, coming from Transgression forms, we obtain finite results without the need for further regularization. Our results are of potential interest for Lovelock gravity theories, as it has been shown that the boundary terms dictated by the transgressions for Chern-Simons gravities are also suitable to regularize Lovelock theories. The Wess-Zumino consistency condition ensures that anomalies of the generic form computed here should appear for these and other theories.
On thermodynamics of AdS black holes in M-theory
International Nuclear Information System (INIS)
Motivated by recent work on asymptotically AdS4 black holes in M-theory, we investigate the thermodynamics and thermodynamical geometry of AdS black holes from M2- and M5-branes. Concretely, we consider AdS black holes in AdSp+2 x S11-p-2, where p = 2,5 by interpreting the number of M2- (and M5-branes) as a thermodynamical variable. More precisely, we study the corresponding phase transition to examine their stabilities by calculating and discussing various thermodynamical quantities including the chemical potential. Then we compute the thermodynamical curvatures from the Quevedo metric for M2- and M5-branes geometries to reconsider the stability of such black holes. The Quevedo metric singularities recover similar stability results provided by the phase-transition program. It has been shown that similar behaviors are also present in the limit of large N. (orig.)
Indian Academy of Sciences (India)
Jacinta S D’souza; Man Mohan Johri
2003-03-01
We have demonstrated the presence of a Ca2+-dependent/calmodulin-stimulated protein kinase (PK) in chloronema cells of the moss Funaria hygrometrica. The kinase, with a molecular mass of 70,000 daltons (PK70), was purified to homogeneity using ammonium sulphate fractionation, DEAE-cellulose chromatography, and calmodulin (CaM)-agarose affinity chromatography. The kinase activity was stimulated at a concentration of 50 M free Ca2+, and was further enhanced 3–5-fold with exogenously added 3–1000 nm moss calmodulin (CaM). Autophosphorylation was also stimulated with Ca2+ and CaM. Under in vitro conditions, PK70 phosphorylated preferentially lysine-rich substrates such as HIIIS and HVS. This PK shares epitopes with the maize Ca2+-dependent/calmodulin-stimulated PK (CCaMK) and also exhibits biochemical properties similar to the maize, lily, and tobacco CCaMK. We have characterized it as a moss CCaMK.
Directory of Open Access Journals (Sweden)
Shigeki Kobayashi
Full Text Available OBJECTIVES: The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. BACKGROUND: The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca(2+ handling in heart failure remains unclear. METHODS: We investigated the effect of milrinone plus landiolol on intracellular Ca(2+ transient (CaT, cell shortening (CS, the frequency of diastolic Ca(2+ sparks (CaSF, and sarcoplasmic reticulum Ca(2+ concentration ({Ca(2+}SR in normal and failing canine cardiomyocytes and used immunoblotting to determine the phosphorylation level of ryanodine receptor (RyR2 and phospholamban (PLB. RESULTS: In failing cardiomyocytes, CaSF significantly increased, and peak CaT and CS markedly decreased compared with normal myocytes. Administration of milrinone alone slightly increased peak CaT and CS, while CaSF greatly increased with a slight increase in {Ca(2+}SR. Co-administration of β1-blocker landiolol to failing cardiomyocytes at a dose that does not inhibit cardiomyocyte function significantly decreased CaSF with a further increase in {Ca(2+}SR, and peak CaT and CS improved compared with milrinone alone. Landiolol suppressed the hyperphosphorylation of RyR2 (Ser2808 in failing cardiomyocytes but had no effect on levels of phosphorylated PLB (Ser16 and Thr17. Low-dose landiolol significantly inhibited the alternans of CaT and CS under a fixed pacing rate (0.5 Hz in failing cardiomyocytes. CONCLUSION: A low-dose β1-blocker in combination with milrinone improved cardiac function in failing cardiomyocytes, apparently by inhibiting the phosphorylation of RyR2, not PLB, and subsequent diastolic Ca(2+ leak.
ADS specific accelerator developments: Status in Japan
International Nuclear Information System (INIS)
In Japan, JAEA proposes an ADS which consists of a high power proton LINAC, a spallation target of lead-bismuth eutectic (LBE) and a subcritical core. In this proposal, the energy and beam power of the high power proton LINAC are 1.5 GeV and 20–30 MW, respectively. Other specifications of the high power proton linac are described in [4.28]. An important technical aspect that is considered in the JAEA work is the negative impact of very frequent beam trips as experienced in existing intense accelerator facilities. Frequent beam trips cause thermal fatigue problems for ADS components materials, leading to degradation of their structural integrity and reduction of their lifetime. They can also badly erode the availability or the capacity of ADS, resulting in poor economics. In the development of accelerators for ADS, it is vitally important to establish the technologies to achieve a very high degree of reliability. On the other hand, JAEA considers that it is also important in the development of ADS to design structural components to withstand possible thermal fatigues and a power conversion system less sensitive to beam trips. The purpose of the JAEA study is the comparison of beam trip frequencies between requirement from ADS transient analyses and estimation from current experimental data of accelerators
McGuirk, Paul
2013-01-01
We consider the behavior of D7 probes of supersymmetric warped geometries that are perturbed by the presence of anti-D3-branes. Such constructions are the gravitational duals of non-supersymmetric states in supersymmetric flavored gauge theories. Although the D7s we consider do not feel a force from either D3s or anti-D3s alone, when both types of 3-branes are present the D7s deform and fall a small distance toward the 3-branes. We perform our analysis in AdS^5 x S^5 and the Klebanov-Witten solution and find qualitatively similar behavior in each case. We then extend our consideration to the approximately conical region of the Klebanov-Strassler solution and find that the effect is parametrically larger than in the AdS^5 x X^5 examples. Additionally, we discuss how these behaviors are modified by the presence of other flavors by considering the backreaction of such flavor branes in AdS^5 x X^5. Finally, we touch upon some of the implications that our results may have for model building and argue that the defo...
Integrable strings for AdS/CFT
Borsato, Riccardo
2016-01-01
In this PhD thesis we review some aspects of integrable models related to string backgrounds or their deformations. In the first part we develop methods to obtain exact results in the AdS3/CFT2 correspondence. We consider the AdS_3 x S^3 x T^4 background with pure Ramond-Ramond flux and we find the all-loop worldsheet S-matrix by exploiting the symmetries of the model in light-cone gauge. As we naturally include the massless modes on the worldsheet, we derive the full set of Bethe-Yang equations. In the massive sector we give also a spin-chain description and we write down solutions compatible with crossing for the scalar factors which are not constrained by simmetries. In the second part of the thesis we consider the so-called "eta-deformation" of the superstring on AdS_5 x S^5. We first discuss the effects of the deformation at the level of the bosonic sigma-model, and we match the tree-level worldsheet scattering processes to the expansion of the q-deformed S-matrix. To identify the missing Ramond-Ramond f...
Galloway, G J; Woolgar, E
2003-01-01
We prove two theorems, announced in hep-th/0801170, for static spacetimes that solve Einstein's equation with negative cosmological constant. The first is a general structure theorem for spacetimes obeying a certain convexity condition near infinity, analogous to the structure theorems of Cheeger and Gromoll for manifolds of non-negative Ricci curvature. For spacetimes with Ricci-flat conformal boundary, the convexity condition is associated with negative mass. The second theorem is a uniqueness theorem for the negative mass AdS soliton spacetime. This result lends support to the new positive mass conjecture due to Horowitz and Myers which states that the unique lowest mass solution which asymptotes to the AdS soliton is the soliton itself. This conjecture was motivated by a nonsupersymmetric version of the AdS/CFT correspondence. Our results add to the growing body of rigorous mathematical results inspired by the AdS/CFT correspondence conjecture. Our techniques exploit a special geometric feature which the ...
Diazoxide unmasks glucose inhibition of insulin release by counteracting entry of Ca2+
International Nuclear Information System (INIS)
The interaction of diazoxide with the effects of glucose on the insulin-releasing mechanism was analyzed in β-cell-rich pancreatic islets isolated from ob/ob mice. When added at a concentration of 400 μM to a medium containing 1.28 mM Ca2+, diazoxide converted glucose stimulation of insulin release into inhibition. Further addition of 2 mM theophylline restored the insulin secretory response to glucose. The paradoxical glucose inhibition of insulin release was accounted for by a diazoxide interaction with the entry of Ca2+, unmasking a capacity of the sugar to lower cytoplasmic Ca2+ below its resting concentration
de Araújo Leite, Jocelmo Cássio; Marques-Santos, Luis Fernando
2012-03-01
The involvement of Ca(2+) in the activation of eggs and in the first steps of the embryonic development of several species is a well-known phenomenon. An association between Ca(2+) sources with the fate of the blastopore during embryonic development has been investigated by several authors. Ca(2+) influx mediated by voltage-gated channels and Ca(2+) mobilization from intracellular stores are the major sources of Ca(2+) to egg activation and succeeding cell divisions. Studies on sea urchins embryonic development show that intracellular Ca(2+) stores are responsible for egg activation and early embryogenesis. In the present work we investigated the involvement of extracellular Ca(2+) in the first stages of the embryonic development of the sea urchin Echinometra lucunter. Divalent cation chelators EDTA and EGTA strongly blocked the early embryonic development. Adding to this, we demonstrated the involvement of voltage-gated Ca(2+) channels in E. lucunter embryogenesis since Ca(2+) channel blockers powerfully inhibited the early embryonic development. Our data also revealed that Ca(2+) influx is crucial for embryonic development during only the first 40 min postfertilization. However, intracellular Ca(2+) remains mandatory to embryonic development 40 min postfertilization, seen that both the intracellular Ca(2+) chelator BAPTA-AM and calmodulin antagonists trifluoperazine and chlorpromazine inhibited the first stages of development when added to embryos culture 50 min postfertilization. Our work highlights the crucial role of extracellular Ca(2+) influx through voltage-gated Ca(2+) channels for the early embryonic development of the sea urchin E. lucunter and characterizes an exception in the phylum Echinodermata. PMID:22532474
Influence of green tea polyphenols on mitochondrial permeabi lity transition pore and Ca2+ transport
Institute of Scientific and Technical Information of China (English)
沈生荣; 于海宁; 金超芳
2002-01-01
The authors investigated the influence of green tea polyphenols (GTPs) on the liver mitochondria permeability transition pore (PTP) opening through mit ochondria swelling and change of mitochondria membrane potential. The data showe d that GTPs had obvious protective effect on the Ca2+-induced PTP opening in a d ose-dependent manner detected by mitochondria swelling. The results were obtain ed by measuring the change of mitochondria membrane potential through Rh 123. Further experiments were conducted to examine the detailed influence of GTP s on Ca2+import and export of mitochondria. The results showed that GTPs h ad rem arkably inhibitory effect on the Ca2+-induced Ca2+ import in mitoch ondria; and t hat they could accelerate Ca2+-release from mitochondria. Our data provid e an al ternate interpretation of the potent protective function of GTPs on cell against apoptosis.
Effects of nitrogen ion implantation on Ca2+ concentration and membrane potential of pollen cell
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The effects of low energy nitrogen ion implantation on Ca2+ concentration and membrane potential of lily (lilium davidii Duch) pollen cell have been studied. The results showed that the Ca2+ concentration was increased when pollen grain was implanted by nitrogen ion with energy 100keV and dose 1013 ions/cra2. However, the increase of Ca2+ concentration was partly inhibited by the addition of Ca2+channel inhibitor depending on dose. And nitrogen ion implantation caused depolarization of pollen cell membrane potential. In other words, membrane potential was increased,but the effect decreased by adding Ca2+ channel inhibitor.However, it was still significantly higher than the membrane potential of control cells. It was indicated that the depolarization of cell membrane potential opened the calcium channel on the membrane that caused the increasing of intraceilular calcium concentration. This might be an earlier step of the effect of low energy nitrogen ion implantation on pollen germination.
Compound Method to Disperse CaCO3 Nanoparticles to Nano-Size in Water.
Gu, Sui; Cai, Jihua; Wang, Jijun; Yuan, Ye; Chang, Dewu; Chikhotkin, Viktor F
2015-12-01
The invalidation of CaCO3 nanoparticles (nCaCO3) is often caused by the fact of agglomeration and inhomogeneous dispersion which limits its application into water-based drilling muds for low permeability reservoirs such as coalbed methane reservoir and shale gas/oil reservoir. Effective methods to disperse nCaCO3 to nano-size (≤ 100 nm) in water have seldom been reported. Here we developed a compound method containing mechanical stirring, ultrasonic treatment, the use of surfactant and stabilizer to disperse nCaCO3 in water. It comprises the steps adding 2% nCaCO3, 1% sodium dodecyl sulfonate (SDS), 2% cetyltrimethyl ammonium bromide (CTAB), 2% OP-10, 3% to 4% biopolymer (XC) in water successively, stirring it at a shear rate of 6000 to 8000 r/min for 15 minutes and treating it with ultrasonic at a frequency of 28 KHz for 30 to 40 minutes. The dispersed nCaCO3 was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and particle size distribution (PSD) tests. We found that nCaCO3 could be dispersed to below 100 nm in water and the medium value of nCaCO3 was below 50 nm. This method paved the way for the utilization of nCaCO3 in drilling fluid and completion fluid for low permeability reservoirs such as coal seams and shale gas/oil formations. PMID:26682370
The Impact of Ad Characteristics on Adolescents’ Attitudes Towards Antismoking Ads
Directory of Open Access Journals (Sweden)
Domen Bajde
2008-03-01
Full Text Available Smoking exerts a considerable burden not only on those who smoke but just as well on society at large. In response, governments and institutions often resort to advertising which aims to discourage smoking. Unfortunately, our knowledge of the workings of antismoking advertising is detrimentally limited. In particular, the literature delving into the impact of antismoking ad characteristics (e. g., ad content, valence, intensity on the overall effectiveness of antismoking advertising is scarce and contradictory. This empirical study aims to enhance the knowledge of antismoking advertising by presenting results of the survey involving Slovene adolescents. The adolescents were first exposed to advertisements of different antismoking ad contents (for the purpose of this study the term ‘ad content’ refers to types of appeals used in antismoking advertising, ad valence and intensity, and later invited to respond to a number of questions measuring their attitudes toward the ads, their attitudes toward smoking, their intentions to smoke, etc. The results indicate that while the different intensity and valence of ads produce varying attitudes toward the ads, we could not confirm these differences based on ad content. Also, we found that adolescent smokers respond to antismoking ads differently than do their nonsmoking peers. Our findings offer several important implications for antismoking advertisers and the research community interested in the workings of antismoking advertising.
Holography of non-relativistic string on AdS5 x S5
International Nuclear Information System (INIS)
We discuss a holographic dual of a non-relativistic (NR) string on AdS5 x S5 . The NR string can be regarded as a semiclassical string around an AdS2 classical solution corresponding to a straight Wilson line in the gauge-theory side. The quadratic action with respect to the fluctuations is composed of free massive and massless scalars, and free massive fermions on the AdS2 world-sheet. We show that the complete agreement of the spectra between the NR string and a conformal quantum mechanics (CQM). Then we show a holographic relation between normalizable modes of the NR string and wave functions in the CQM. Then it may be argued from this result that an AdS2/CFT1 would be realized in AdS5/CFT4. We can really discuss a GKPW-type relation by considering non-normalizable modes of the NR string in Euclidean signature. Those modes give a source term insertion to the Wilson line, which can also be regarded as a small deformation of it
International Nuclear Information System (INIS)
This document assumes that you have read and understood the Wingz user's manuals. CaWingz is an external Wingz program which, when combined with a set of script files, provides easy-to-use EPICS channel access interface functions for Wingz users. The external function run allows Wingz user to invoke any Unix processor within caWingz. Few additional functions for accessing static database field and monitoring of value change event is available for EPICS users after release 3.11. The functions, script files, and usage are briefly described in this document. The script files supplied here serve as examples only. Users are responsible for generating their own spreadsheet and script files. CaWingz communicates with IOC through channel access function calls
Ethanol oxidation on Pd/C promoted with CaSiO3 in alkaline medium
International Nuclear Information System (INIS)
Highlights: • Thermal-decomposed CaSiO3 was added to XC-72 carbon black as composite support. • Modified electronic structure of Pd facilitates the detachment of CO from Pd surface. • CaSiO3 enhances proton transfer process and improves dehydrogenation process. • CaSiO3 promotes oxidation removal of CO due to easier OH− adsorption on electrode. • Pd/50CaSiO3/C catalyst shows highest activity and stability for ethanol oxidation. - Abstract: In this paper, CaSiO3 was prepared using a thermal decomposition approach and added to Vulcan XC-72 carbon black as support material. The X-ray diffraction and Transmission electron microscopy results show that the addition of CaSiO3 does not significantly change the particle size and distribution of Pd nanoparticles. The X-ray photoelectron spectroscopy reveals the interaction between Pd and CaSiO3. In addition, the electrochemical CO-striping measurement reveals that the Pd/50CaSiO3/C catalyst exhibits the largest electrochemical active surface and best CO tolerance. Moreover, cyclic voltammetry and chronoamperometry tests demonstrate that the Pd supported by CaSiO3 and C (50:50 in wt.%) possesses a much higher current density (1408 mA mg−1) than that of the Pd/C catalyst (743 mA mg−1) towards ethanol oxidation in alkaline media, and better stability as well. These results support the suitability of Pd/50CaSiO3/C catalyst developed in this work as a promising candidate for direct ethanol fuel cells application
Kay, Bernard S.; Ortíz, L.
2014-05-01
We discuss the relationship between the bulk-boundary correspondence in Rehren's algebraic holography (and in other `fixed-background', QFT-based, approaches to holography) and in mainstream string-theoretic `Maldacena AdS/CFT'. Especially, we contrast the understanding of black-hole entropy from the point of view of QFT in curved spacetime—in the framework of 't Hooft's `brick wall' model—with the understanding based on Maldacena AdS/CFT. We show that the brick-wall modification of a Klein-Gordon field in the Hartle-Hawking-Israel state on dimensional Schwarzschild AdS has a well-defined boundary limit with the same temperature and entropy as the brick-wall-modified bulk theory. One of our main purposes is to point out a close connection, for general AdS/CFT situations, between the puzzle raised by Arnsdorf and Smolin regarding the relationship between Rehren's algebraic holography and mainstream AdS/CFT and the puzzle embodied in the `complementarity principle' proposed by Mukohyama and Israel in their work on the brick-wall approach to black hole entropy. Working on the assumption that similar results will hold for bulk QFT other than the Klein-Gordon field and for Schwarzschild AdS in other dimensions, and recalling the first author's proposed resolution to the Mukohyama-Israel puzzle based on his `matter-gravity entanglement hypothesis', we argue that, in Maldacena AdS/CFT, the algebra of the boundary CFT is isomorphic only to a proper subalgebra of the bulk algebra, albeit (at non-zero temperature) the (GNS) Hilbert spaces of bulk and boundary theories are still the `same'—the total bulk state being pure, while the boundary state is mixed (thermal). We also argue from the finiteness of its boundary (and hence, on our assumptions, also bulk) entropy at finite temperature, that the Rehren dual of the Maldacena boundary CFT cannot itself be a QFT and must, instead, presumably be something like a string theory.
Inter-Cluster Routing Authentication for Ad Hoc Networks by a Hierarchical Key Scheme
Institute of Scientific and Technical Information of China (English)
Yueh-Min Huang; Hua-Yi Lin; Tzone-I Wang
2006-01-01
Dissimilar to traditional networks, the features of mobile wireless devices that can actively form a network without any infrastructure mean that mobile ad hoc networks frequently display partition due to node mobility or link failures. These indicate that an ad hoc network is difficult to provide on-line access to a trusted authority server. Therefore,applying traditional Public Key Infrastructure (PKI) security framework to mobile ad hoc networks will cause insecurities.This study proposes a scalable and elastic key management scheme integrated into Cluster Based Secure Routing Protocol (CBSRP) to enhance security and non-repudiation of routing authentication, and introduces an ID-Based internal routing authentication scheme to enhance the routing performance in an internal cluster. Additionally, a method of performing routing authentication between internal and external clusters, as well as inter-cluster routing authentication, is developed.The proposed cluster-based key management scheme distributes trust to an aggregation of cluster heads using a threshold scheme faculty, provides Certificate Authority (CA) with a fault tolerance mechanism to prevent a single point of compromise or failure, and saves CA large repositories from maintaining member certificates, making ad hoc networks robust to malicious behaviors and suitable for numerous mobile devices.
Natsuume, Makoto
2015-01-01
This book describes applications of the AdS/CFT duality to the "real world." The AdS/CFT duality is an idea that originated from string theory and is a powerful tool for analyzing strongly-coupled gauge theories using classical gravitational theories. In recent years, it has been shown that one prediction of AdS/CFT is indeed close to the experimental result of the real quark–gluon plasma. Since then, the AdS/CFT duality has been applied to various fields of physics; examples are QCD, nuclear physics, condensed-matter physics, and nonequilibrium physics. The aim of this book is to provide background materials such as string theory, black holes, nuclear physics, condensed-matter physics, and nonequilibrium physics as well as key applications of the AdS/CFT duality in a single volume. The emphasis throughout the book is on a pedagogical and intuitive approach focusing on the underlying physical concepts. It also includes step-by-step computations for important results, which are useful for beginners. Th...
International Programmes on ADS: European Commission
International Nuclear Information System (INIS)
Euratom research projects related to the design and the use of ADS facilities started in the 4th Framework Programme (FP4) (1996–2001) with the project ‘Impact of Accelerator Based Technologies on Nuclear Fission Safety—IABAT’. The overall objective of the IABAT project was a preliminary assessment of the potential of Accelerator Driven Systems for transmutation of radioactive waste and, additionally, for nuclear energy production with minimum waste generation. This first project was followed by a much larger ADS oriented programmes in the FP5 (2002–2005), FP6 (2005–2010) and FP7 (2008–2013). In the frame of the FP6, special attention was devoted to the EUROTRANS integrated Project (2005–2010), dedicated to study the transmutation of high level radioactive waste in an ADS. Based on the three FP5 Clusters FUETRA, BASTRA and TESTRA together with the PDS-XADS Project, the EUROTRANS Project was aimed to carry out a first advanced design of an approximately 50 to 100 MWth eXperimental facility (realization in a short term, say about 10 years) demonstrating the technical feasibility of Transmutation in an ADS (XT ADS), as well as to accomplish a generic conceptual design (several 100 MWth) of a modular European Facility for Industrial Transmutation (EFIT) (realisation in the long term)
Gubser, S S
2001-01-01
The radiation-dominated k=0 FRW cosmology emerges as the induced metric on a codimension one hypersurface of constant extrinsic curvature in the five-dimensional AdS-Schwarzschild solution. That we should get FRW cosmology in this way is an expected result from AdS/CFT in light of recent comments regarding the coupling of gravity to "boundary" conformal field theories. I remark on how this calculation bears on the understanding of Randall and Sundrum's "alternative to compactification." A generalization of the AdS/CFT prescription for computing Green's functions is suggested, and it is shown how gravity emerges from it with a strength G_4 = 2 G_5/L. Some numerical bounds are set on the radius of curvature L of AdS_5. One of them comes from estimating the rate of leakage of visible sector energy into the CFT. That rate is connected via a unitarity relation to deviations from Newton's force law at short distances. The best bound on L obtained in this paper comes from a match to the parameters of string theory. ...
Black hole microstates in AdS$_4$ from supersymmetric localization
Benini, Francesco; Zaffaroni, Alberto
2015-01-01
This paper addresses a long standing problem, the counting of the microstates of supersymmetric asymptotically AdS black holes in terms of a holographically dual field theory. We focus on a class of asymptotically AdS$_4$ static black holes preserving two real supercharges which are dual to a topologically twisted deformation of the ABJM theory. We evaluate in the large $N$ limit the topologically twisted index of the ABJM theory and we show that it correctly reproduces the entropy of the AdS$_4$ black holes. An extremization of the index with respect to a set of chemical potentials is required. We interpret it as the selection of the exact R-symmetry of the superconformal quantum mechanics describing the horizon of the black hole.
Solutions in Bosonic String Field Theory and Higher Spin Algebras in AdS
Polyakov, Dimitri
2015-01-01
We find a class of analytic solutions in open bosonic string field theory, parametrized by the chiral copy of higher spin algebra in $AdS_3$. The solutions are expressed in terms of the generating function for the products of Bell polynomials in derivatives of bosonic space-time coordinates $X^m(z)$ of the open string, which form is determined in this work. The products of these polynomials form a natural operator algebra realizations of $W_\\infty$ (area-preserving diffeomorphisms), enveloping algebra of SU(2) and higher spin algebra in $AdS_3$. The class of SFT solutions found can, in turn, be interpreted as the "enveloping of enveloping", or the enveloping of $AdS_3$ higher spin algebra. We also discuss the extensions of this class of solutions to superstring theory and their relations to higher spin algebras in higher space-time dimensions.
On thermodynamics of AdS black holes in M-theory
Energy Technology Data Exchange (ETDEWEB)
Belhaj, A. [Universite Sultan Moulay Slimane, Departement de Physique, LIRST, Faculte Polydisciplinaire, Beni Mellal (Morocco); Cadi Ayyad University, High Energy Physics and Astrophysics Laboratory, FSSM, Marrakesh (Morocco); Chabab, M.; Masmar, K. [Cadi Ayyad University, High Energy Physics and Astrophysics Laboratory, FSSM, Marrakesh (Morocco); El Moumni, H. [Cadi Ayyad University, High Energy Physics and Astrophysics Laboratory, FSSM, Marrakesh (Morocco); Universite Ibn Zohr, Departement de Physique, Faculte des Sciences, Agadir (Morocco); Sedra, M.B. [Universite Ibn Tofail, Departement de Physique, LASIMO, Faculte des Sciences, Kenitra (Morocco)
2016-02-15
Motivated by recent work on asymptotically AdS{sub 4} black holes in M-theory, we investigate the thermodynamics and thermodynamical geometry of AdS black holes from M2- and M5-branes. Concretely, we consider AdS black holes in AdS{sub p+2} x S{sup 11-p-2}, where p = 2,5 by interpreting the number of M2- (and M5-branes) as a thermodynamical variable. More precisely, we study the corresponding phase transition to examine their stabilities by calculating and discussing various thermodynamical quantities including the chemical potential. Then we compute the thermodynamical curvatures from the Quevedo metric for M2- and M5-branes geometries to reconsider the stability of such black holes. The Quevedo metric singularities recover similar stability results provided by the phase-transition program. It has been shown that similar behaviors are also present in the limit of large N. (orig.)
Non-spherical collapse in AdS and early thermalization in RHIC
International Nuclear Information System (INIS)
In the flat space, non-spherical shells collapse to give globular cluster after many oscillations. We show that in anti de Sitter space, they form black holes in one dynamical time. We propose that this is the mechanism of early thermalization in strong quark–gluon plasma in gravity dual. This is traced back to the a remarkable property of AdS: the period in radial motion is amplitude independent in spite of the non-linearity of the equation of motion. We investigate the interaction effect numerically and observe the same qualitative behavior for the attractive forces. For repulsive interactions, particles halt at a small but finite radius for long time due to the specific structure of the bulk AdS propagator. It helps hair creation in the AdS black hole
QCD Condensates and Holographic Wilson Loops for Asymptotically AdS Spaces
Energy Technology Data Exchange (ETDEWEB)
Quevedo, R. Carcasses [Instituto Balseiro, Centro Atomico Bariloche, 8400 San Carlos de Bariloche (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Goity, Jose L. [Hampton University, Hampton, VA 23668 (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Trinchero, Roberto C. [Instituto Balseiro, Centro Atomico Bariloche, 8400 San Carlos de Bariloche (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina)
2014-02-01
The minimization of the Nambu-Goto (NG) action for a surface whose contour defines a circular Wilson loop of radius a placed at a finite value of the coordinate orthogonal to the border is considered. This is done for asymptotically AdS spaces. The condensates of dimension n = 2, 4, 6, 8, and 10 are calculated in terms of the coefficients in the expansion in powers of the radius a of the on-shell subtracted NG action for small a->0. The subtraction employed is such that it presents no conflict with conformal invariance in the AdS case and need not introduce an additional infrared scale for the case of confining geometries. It is shown that the UV value of the gluon condensates is universal in the sense that it only depends on the first coefficients of the difference with the AdS case.
Analytical study on holographic superfluid in AdS soliton background
Lai, Chuyu; Pan, Qiyuan; Jing, Jiliang; Wang, Yongjiu
2016-06-01
We analytically study the holographic superfluid phase transition in the AdS soliton background by using the variational method for the Sturm-Liouville eigenvalue problem. By investigating the holographic s-wave and p-wave superfluid models in the probe limit, we observe that the spatial component of the gauge field will hinder the phase transition. Moreover, we note that, different from the AdS black hole spacetime, in the AdS soliton background the holographic superfluid phase transition always belongs to the second order and the critical exponent of the system takes the mean-field value in both s-wave and p-wave models. Our analytical results are found to be in good agreement with the numerical findings.
A Mean-Field Description for AdS Black Hole
Dutta, Suvankar
2016-01-01
In this paper we find an equivalent mean-field description for asymptotically $AdS$ black hole in high temperature limit and in arbitrary dimensions. We obtain a class of mean-field potential for which the description is valid. We explicitly show that there is an one to one correspondence between the thermodynamics of a gas of interacting particles moving under a mean-field potential and an $AdS$ black hole, namely the equation of state, temperature, pressure, entropy and enthalpy of both the systems match. In $3+1$ dimensions, in particular, the mean-field description can be thought of as an ensemble of tiny interacting {\\it asymptotically flat} black holes moving in volume $V$ and at temperature $T$. This motivates us to identify these asymptotically flat black holes as microstructure of asymptotically $AdS$ black holes in $3+1$ dimensions.
A Stochasticity Threshold in Holography and and the Instability of AdS
Basu, Pallab; Saurabh, Ayush
2014-01-01
We give strong numerical evidence that a self-interacting probe scalar field in AdS, with only a few modes turned on initially, will undergo fast thermalization only if it is above a certain energetic threshold. Below the threshold the energy stays close to constant in a few modes for a very long time instead of cascading quickly. This indicates the existance of a Strong Stochasticity Threshold (SST) in holography. The idea of SST is familiar from certain statistical mechanical systems, and we suggest that it exists also in AdS gravity. This would naturally reconcile the generic non-linear instability of AdS observed by Bizon and Rostworowski, with the Fermi-Pasta-Ulam-Tsingou-like quasi-periodocity noticed recently for some classes of initial conditions. We show that our simple set-up captures many of the relevant features of the full gravity-scalar system.
Photon gas thermodynamics in dS and AdS momentum spaces
Gorji, M A; Nozari, K; Vakili, B
2016-01-01
In this paper, we study thermostatistical properties of a photon gas in the framework of two deformed special relativity models defined by the cosmological coordinatizations of the de Sitter (dS) and anti-de Sitter (AdS) momentum spaces. The dS model is a doubly special relativity theory in which an ultraviolet length scale is invariant under the deformed Lorentz transformations. For the case of AdS model, however, the Lorentz symmetry breaks at the high energy regime. We show that the existence of a maximal momentum in dS momentum space leads to maximal pressure and temperature at the thermodynamical level while maximal internal energy and entropy arise for the case of the AdS momentum space due to the existence of a maximal kinematical energy. These results show the thermodynamical duality of these models much similar to their well-known kinematical duality.
Higher spin holography and the AdS string sigma model
International Nuclear Information System (INIS)
We analyse the cubic spin-3 interaction in AdS space using the higher spin extension of the string-theoretic sigma-model constructed in our previous work, whose low energy limit is described by the AdS vacuum solution. We find that, in the leading order of the cosmological constant, the spin-3 correlator on the AdS4 string theory side reproduces the structure of the three-point function of composite operators, quadratic in free fields, in the dual d = 3 vector model. The cancellation of holography violating terms in d = 3 is related to the value of the Liouville background charge in d = 4. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Higher spin theories and holography’. (paper)
Spinning strings in AdS3×S3 with NS–NS flux
Directory of Open Access Journals (Sweden)
Rafael Hernández
2014-11-01
Full Text Available The sigma model describing closed strings rotating in AdS3×S3 is known to reduce to the one-dimensional Neumann–Rosochatius integrable system. In this article we show that closed spinning strings in AdS3×S3×T4 in the presence of NS–NS three-form flux can be described by an extension of the Neumann–Rosochatius system. We consider closed strings rotating with one spin in AdS3 and two different angular momenta in S3. For a class of solutions with constant radii we find the dependence of the classical energy on the spin and the angular momenta as an expansion in the square of the 't Hooft coupling of the theory.
Conformally coupled scalars, instantons and vacuum instability in AdS4
International Nuclear Information System (INIS)
We show that a scalar field conformally coupled to AdS gravity in four dimensions with a quartic self-interaction can be embedded into M-theory. The holographic effective action and effective potential are exactly calculated, allowing us to study non-perturbatively the stability of AdS4 in the presence of the conformally coupled scalar. It is shown that there exists a one-parameter family of conformal scalar boundary conditions for which the boundary theory has an unstable vacuum. In this case, the bulk theory has instanton solutions that mediate the decay of the AdS4 space. These results match nicely with the vacuum structure and the existence of instantons in an effective three-dimensional boundary model
Symmetries of the Boundary of $AdS_{5} \\times S^{5}$ and Harmonic Superspace
Claus, P; Rahmfeld, J; Claus, Piet; Kallosh, Renata
1999-01-01
We study the boundary limit of the bulk isometries of AdS x S. The superconformal symmetry is realized on the coordinates of the AdS boundary, the fermionic superspace coordinates, and the harmonics on the sphere. We show how these may be related to the coordinates of an off-shell harmonic superspace of SCFT living on the boundary. In the special case of d=4, N=2 super Yang-Mills theory, a truncation of the N=4 SYM dual to Type IIB string theory compactified on AdS_5 x S^5, we identify the bosonic space $SU(2)/U(1)$ of the N=2 harmonic superspace (known before as auxiliary) with the S^2 submanifold of the S^5.
2D Gravity on $AdS_2$ with Chern-Simons Corrections
Alishahiha, Mohsen; Mosaffa, Amir E
2009-01-01
We study 2D Maxwell-dilaton gravity with higher order corrections given by the Chern-Simons term. The model admits three distinctive $AdS_2$ vacuum solutions. By making use of the entropy function formalism we find the entropy of the solutions which is corrected due to the presence of the Chern-Simons term. We observe that the form of the correction depends not only on the coefficient of the Chern-Simons term, but also on the sign of the electric charge; pointing toward the chiral nature of the dual CFT. Using the asymptotic symmetry of the theory as well as requiring a consistent picture we can find the central charge and the level of U(1) current. Upon uplifting the solutions to three dimensions we get purely geometric solutions which will be either $AdS_3$ or warped $AdS_3$ with an identification.
Area products for ${\\cal H}^{\\pm}$ in AdS space
Pradhan, Parthapratim
2016-01-01
We derive the thermodynamic products particularly area (or entropy) products of ${\\cal H}^{\\pm}$ for certain class of black holes in AdS space. We show by explicit calculations that more complicated function of event horizon area and Cauchy horizon area is indeed mass-independent. This mass-independent quantities indicate that they could turn out to be an "universal" quantity provided that they depends only on the quantized angular momentum, quantized charges, and cosmological constant. Furthermore, these area (or entropy) product relations for several class of black holes in AdS space gives us strong indication to understanding the nature of non-extremal black hole entropy (both inner and outer) at the microscopic level. Moreover, we compute the famous \\emph{Penrose inequality} for these class of black holes in AdS space. Local thermodynamic stability has been discussed for these black holes and under certain condition these black holes displayed second order phase transition.
Ad-blocking Games: Monetizing Online Content Under the Threat of Ad Avoidance
Vratonjic, Nevena; Manshaei, Mohammadhossein; Grossklags, Jens; Hubaux, Jean-Pierre
2012-01-01
Much of the Internet economy relies on online advertising for monetizing digital content: Users are expected to accept the presence of online advertisements in exchange for content being free. However, online advertisements have become a serious problem for many Internet users: while some are merely annoyed by the incessant display of distracting ads cluttering Web pages, others are highly concerned about the privacy implications - as ad providers typically track users' behavior for ad target...
Interpolating from Bianchi attractors to Lifshitz and AdS spacetimes
International Nuclear Information System (INIS)
We construct classes of smooth metrics which interpolate from Bianchi attractor geometries of Types II, III, VI and IX in the IR to Lifshitz or AdS2×S3 geometries in the UV. While we do not obtain these metrics as solutions of Einstein gravity coupled to a simple matter field theory, we show that the matter sector stress-energy required to support these geometries (via the Einstein equations) does satisfy the weak, and therefore also the null, energy condition. Since Lifshitz or AdS2×S3 geometries can in turn be connected to AdS5 spacetime, our results show that there is no barrier, at least at the level of the energy conditions, for solutions to arise connecting these Bianchi attractor geometries to AdS5 spacetime. The asymptotic AdS5 spacetime has no non-normalizable metric deformation turned on, which suggests that furthermore, the Bianchi attractor geometries can be the IR geometries dual to field theories living in flat space, with the breaking of symmetries being either spontaneous or due to sources for other fields. Finally, we show that for a large class of flows which connect two Bianchi attractors, a C-function can be defined which is monotonically decreasing from the UV to the IR as long as the null energy condition is satisfied. However, except for special examples of Bianchi attractors (including AdS space), this function does not attain a finite and non-vanishing constant value at the end points
A paucity of bulk entangling surfaces: AdS wormholes with de Sitter interiors
Fischetti, Sebastian; Marolf, Donald; Wall, Aron C.
2014-01-01
We study and construct spacetimes, dubbed planar AdS-dS-wormholes, satisfying the null energy condition and having two asymptotically AdS boundaries connected through a (non-traversable) inflating wormhole. As for other wormholes, it is natural to expect dual descriptions in terms of two disconnected CFTs in appropriate entangled states. But for our cases certain expected bulk entangling surfaces used by the Hubeny-Rangamani-Takayanagi (HRT) prescription to compute CFT entropy do not exist. I...
Directory of Open Access Journals (Sweden)
Zsolt Pónya
2014-12-01
Full Text Available During in vitro fertilization of wheat (Triticum aestivum, L. in egg cells isolated at various developmental stages, changes in cytosolic free calcium ([Ca2+]cyt were observed. The dynamics of [Ca2+]cyt elevation varied, reflecting the difference in the developmental stage of the eggs used. [Ca2+]cyt oscillation was exclusively observed in fertile, mature egg cells fused with the sperm cell. To determine how [Ca2+]cyt oscillation in mature egg cells is generated, egg cells were incubated in thapsigargin, which proved to be a specific inhibitor of the endoplasmic reticulum (ER Ca2+-ATPase in wheat egg cells. In unfertilized egg cells, the addition of thapsigargin caused an abrupt transient increase in [Ca2+]cyt in the absence of extracellular Ca2+, suggesting that an influx pathway for Ca2+ is activated by thapsigargin. The [Ca2+]cyt oscillation seemed to require the filling of an intracellular calcium store for the onset of which, calcium influx through the plasma membrane appeared essential. This was demonstrated by omitting extracellular calcium from (or adding GdCl3 to the fusion medium, which prevented [Ca2+]cyt oscillation in mature egg cells fused with the sperm. Combined, these data permit the hypothesis that the first sperm-induced transient increase in [Ca2+]cyt depletes an intracellular Ca2+ store, triggering an increase in plasma membrane Ca2+ permeability, and this enhanced Ca2+ influx results in [Ca2+]cyt oscillation.
Menthol increases human glioblastoma intracellular Ca2+, BK channel activity and cell migration
Directory of Open Access Journals (Sweden)
Bartley Jeremy W
2009-09-01
Full Text Available Abstract This study examined the effect of menthol, an agonist for transient receptor potential melastatin 8 (TRPM8 ion channels, to increase intracellular Ca2+ concentration, [Ca2+]i, in human glioblastoma cells (DBTRG cells, which resulted in activation of the large-conductance Ca2+-activated K+ membrane ion channels (BK channels. Voltage ramps applied over 300 ms from -100 to 100 mV resulted in membrane currents with marked inwardly- and outwardly-rectifying components. Paxilline (2 μM abolished the outwardly-rectifying current. Outwardly-rectifying on-cell patch currents were increased markedly by menthol (100 μM added to the bath. The estimated on-cell conductance of these channels was 253 pS. Kinetic analysis showed that added menthol increased channel open probability and mean open frequency after 5 min. In a similar time course menthol increased [Ca2+]i, and this increase was abolished either by added paxilline, tetraethylammonium ion or by Ca2+-free external solution. Finally, menthol stimulated the rate of DBTRG cell migration into scratch wounds made in confluent cells, and this also was inhibited by paxilline or by tetraethylammonium ion. We conclude that menthol, a TRPM8 agonist, increases DBTRG cell [Ca2+]i that in turn activates membrane BK ion channels. Inhibition of BK channels by paxilline reverses menthol-stimulated increase of [Ca2+]i and of cell migration. Thus, BK channels function to maintain elevations in [Ca2+]i needed to sustain increases in DBTRG cell migration.
Energy Technology Data Exchange (ETDEWEB)
Qi, Liqian; Liu, Jiaxiang; Liu, Qian, E-mail: ljxpost@263.net [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, The State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing (China)
2016-03-15
In this study, we replaced 30% of the cement with steel slag to prepare binding material; additionally, small amounts of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were added. This was done to study the compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O on the strength of steel slag-cement binding materials. The hydration degree of the steel slag cementitious material was analyzed by XRD, TG and SEM. The results showed that the optimum proportions of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were 3% and 2%, respectively. Compared with the steel slag-cement binders without adding CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O, the compressive strength increased by 59.9% at 3 days and by 17.8% at 28 days. Acting as the nucleation matrix, CaCO{sub 3} could accelerate the hydration of C{sub 3}S. In addition, CaCO{sub 3} was involved in the hydration reaction, generating a new hydration product, which could stably exist in a slurry. Meanwhile, CaSO{sub 4}·2H{sub 2}O could increase the number of AFt. The compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O enhanced the intensity of steel slag-cement binding materials and improved the whole hydration behavior. (author)
International Nuclear Information System (INIS)
This document aims at presenting in a synthetic way the present day situation of the progress of technical feasibility studies of an accelerator driven system (ADS) for the transmutation of long-lived radioactive wastes. It aims also at defining the goals to be confirmed or to reach in order to consider the transmutation option in the national debate on radioactive wastes management: - present day evaluation results about the technical feasibility of an ADS: nuclear data, ADS reactor physics, accelerator, spallation target, nuclear fuels; - goals to be confirmed or to be reached: nuclear data, accelerator, spallation target, fuels, coolant, demonstration experiment; - planning of actions: TWG road-map, updated road-map. (J.S.)
Profiling value added position in FM
DEFF Research Database (Denmark)
Katchamart, Akarapong
The dissertation is a research based contribution to the on-going professional discussion among researchers and practitioners within Facilities Management (FM) about whether and why FM organizations should be established with a managerial position which can act as a corporate strategic player. It....... Enhance - FM organizations influence the business productivities and outcome Each type of value added requires specific conditions and contingencies involved. This research thus offers a visual aid tool, “FM product-process matrix”, to assist practitioners to indicate their existing circumstances and...... contexts and assess the current FM value added position and project for the next desirable value added position. It can be used to frame and re-frame the continual dialogue between related stakeholders and FM practitioners, both internal FM organization and external service providers. The research unfolds...
International Programmes on ADS: OECD-NEA
International Nuclear Information System (INIS)
The present study compares FR and ADS based actinide transmutation systems with respect to reactor properties, fuel cycle requirements, economic aspects, and R&D needs. The essential differences between the various systems are evaluated with the help of a number of representative fuel cycle schemes. The strategies investigated include an evolutionary transmutation strategy in which the ADS provides additional flexibility by enabling plutonium utilisation in conventional reactors and confining the minor actinides to a small part of the fuel cycle, and two innovative transuranics (TRU) burning strategies, with an FR or an ADS, in which plutonium and minor actinides are managed together to minimize the proliferation risk. A novelty in the present study is that the analyses are carried out in a consistent manner using reactor and fuel cycle parameters which have been agreed upon by international experts
ADS National Programmes: Republic of Korea
International Nuclear Information System (INIS)
ADS research of Korea was carried out at KAERI (Korea Atomic Energy Research Institute) for the transmutation of long lived nuclides in spent fuels. The KAERI ADS system was called HYPER (HYbrid Power Extraction Reactor). The HYPER research was carried out as a 10 year nuclear research programme funded by the government. The ADS research of KAERI consisted of 3 phases. A basic concept of HYPER was established in the first phase (1997– 2000) of the development. The key technologies related to HYPER was studied in the second phase (2001–2003) while upgrading the design. The conceptual design of HYPER core was completed in the third phase (2004–2006). The research of key technologies was continued in the third phase. The research results can be summarized in three categories: Design and analysis; Fuel experiment; Pb-Bi experiment
Introduction to AdS/CFT correspondence
Nastase, Horatiu
2015-01-01
Providing a pedagogical introduction to the rapidly developing field of AdS/CFT correspondence, this is one of the first texts to provide an accessible introduction to all the necessary concepts needed to engage with the methods, tools and applications of AdS/CFT. Without assuming anything beyond an introductory course in quantum field theory, it begins by guiding the reader through the basic concepts of field theory and gauge theory, general relativity, supersymmetry, supergravity, string theory and conformal field theory, before moving on to give a clear and rigorous account of AdS/CFT correspondence. The final section discusses the more specialised applications, including QCD, quark-gluon plasma and condensed matter. This book is self-contained and learner-focused, featuring numerous exercises and examples. It is essential reading for both students and researchers across the fields of particle, nuclear and condensed matter physics.
Online Stochastic Ad Allocation: Efficiency and Fairness
Feldman, Jon; Korula, Nitish; Mirrokni, Vahab S; Stein, Cliff
2010-01-01
We study the efficiency and fairness of online stochastic display ad allocation algorithms from a theoretical and practical standpoint. In particular, we study the problem of maximizing efficiency in the presence of stochastic information. In this setting, each advertiser has a maximum demand for impressions of display ads that will arrive online. In our model, inspired by the concept of free disposal in economics, we assume that impressions that are given to an advertiser above her demand are given to her for free. Our main theoretical result is to present a training-based algorithm that achieves a (1-\\epsilon)-approximation guarantee in the random order stochastic model. In the corresponding online matching problem, we learn a dual variable for each advertiser, based on data obtained from a sample of impressions. We also discuss different fairness measures in online ad allocation, based on comparison to an ideal offline fair solution, and develop algorithms to compute "fair" allocations. We then discuss sev...
Secure Clustering in Vehicular Ad Hoc Networks
Directory of Open Access Journals (Sweden)
Zainab Nayyar
2015-09-01
Full Text Available A vehicular Ad-hoc network is composed of moving cars as nodes without any infrastructure. Nodes self-organize to form a network over radio links. Security issues are commonly observed in vehicular ad hoc networks; like authentication and authorization issues. Secure Clustering plays a significant role in VANETs. In recent years, various secure clustering techniques with distinguishing feature have been newly proposed. In order to provide a comprehensive understanding of these techniques are designed for VANETs and pave the way for the further research, a survey of the secure clustering techniques is discussed in detail in this paper. Qualitatively, as a result of highlighting various techniques of secure clustering certain conclusions are drawn which will enhance the availability and security of vehicular ad hoc networks. Nodes present in the clusters will work more efficiently and the message passing within the nodes will also get more authenticated from the cluster heads.
Data Confidentiality in Mobile Ad hoc Networks
Aldabbas, Hamza; Janicke, Helge; Al-Bayatti, Ali; 10.5121/ijwmn.2012.4117
2012-01-01
Mobile ad hoc networks (MANETs) are self-configuring infrastructure-less networks comprised of mobile nodes that communicate over wireless links without any central control on a peer-to-peer basis. These individual nodes act as routers to forward both their own data and also their neighbours' data by sending and receiving packets to and from other nodes in the network. The relatively easy configuration and the quick deployment make ad hoc networks suitable the emergency situations (such as human or natural disasters) and for military units in enemy territory. Securing data dissemination between these nodes in such networks, however, is a very challenging task. Exposing such information to anyone else other than the intended nodes could cause a privacy and confidentiality breach, particularly in military scenarios. In this paper we present a novel framework to enhance the privacy and data confidentiality in mobile ad hoc networks by attaching the originator policies to the messages as they are sent between nod...
Superradiance Instability of Small Rotating AdS Black Holes in Arbitrary Dimensions
Delice, Özgür
2015-01-01
We investigate the stability of $D$ dimensional singly rotating Myers-Perry-AdS black holes under superradiance against scalar field perturbations. It is well known that small four dimensional rotating or charged AdS black holes are unstable against superradiance instability of a scalar field. Recent works extended the existence of this instability to five dimensional rotating charged AdS black holes or static charged AdS Black holes in arbitrary dimensions. In this work we analytically prove that, rotating small AdS black holes in arbitrary dimensions also show superradiance instability irrespective of the value of the (positive) angular momentum quantum number. To do this we solve the Klein-Gordon equation in the slow rotation, low frequency limit. By using the asymptotic matching technique, we are able to calculate the real and imaginary parts of the correction terms to the frequency of the scalar field due to the presence of the black hole, confirming the presence of superradiance instability. We see that...
Double-trace deformations and entanglement entropy in AdS
International Nuclear Information System (INIS)
We compute the bulk entanglement entropy of a massive scalar field in a Poincare AdS with the Dirichlet and Neumann boundary condition when we trace out a half space. Moreover, by taking into account the quantum back reaction to the minimal surface area, we calculate how much the entanglement entropy changes under a double-trace deformation of a holographic CFT. In the AdS3/CFT2 setup, our result agrees with the known result in 2d CFTs. In higher dimensions, our results offer holographic predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
AdS and pp-wave D-particle superalgebras
International Nuclear Information System (INIS)
We derive anti commutators of supercharges with a brane charge for a D-particle in AdS(2) x S(2) and pp-wave backgrounds. A coset GL(2|2)/(GL(1))4 and its Penrose limit are used with the supermatrix-valued coordinates for the AdS and the pp-wave spaces respectively. The brane charges have position dependence, and can be absorbed into bosonic generators by shift of momenta which results in closure of the superalgebras. (author)
Critical phenomena in higher curvature charged AdS black holes
Arindam Lala
2012-01-01
In this paper we have studied the critical phenomena in higher curvature charged black holes in the anti-de Sitter (AdS) space-time. As an example we have considered the third order Lovelock-Born-Infeld black holes in AdS space-time. We have analytically derived the thermodynamic quantities of the system. Our analysis revealed the onset of a higher order phase transition in the black hole leading to an infinite discontinuity in the specific heat at constant charge at the critical points. Our ...
A Mean-Field Description for AdS Black Hole
Dutta, Suvankar; P, Sachin Shain
2016-01-01
In this paper we find an equivalent mean-field description for asymptotically $AdS$ black hole in high temperature limit and in arbitrary dimensions. We obtain a class of mean-field potential for which the description is valid. We explicitly show that there is an one to one correspondence between the thermodynamics of a gas of interacting particles moving under a mean-field potential and an $AdS$ black hole, namely the equation of state, temperature, pressure, entropy and enthalpy of both the...
Holography of Non-relativistic String on AdS5xS5
International Nuclear Information System (INIS)
We review a holography of a non-relativistic (NR) string on AdS5xS5. The NR string can be regarded as a semiclassical string around an AdS2 classical solution, which corresponds to a straight Wilson line in the gauge-theory side. Non-normalizable modes of the NR string correspond to string fluctuations reaching the boundary, and cause small deformations of the Wilson line. The operator inserted on the Wilson line are found from the small deformation of the Wilson line. Normalizable modes, which exist in the Lorentzian case, are considered as wave functions in a conformal quantum mechanics.
Half BPS states in AdS_5 x Y^{p,q}
Gava, Edi; Narain, Kumar S.; Milanesi, Giuseppe; O'Loughlin, Martin
2007-01-01
We study a class of solutions of IIB Supergravity which are asymptotically AdS_5 x Y^{p,q}. They have an R x SO(4) x SU(2) x U(1) isometry and preserve half of the 8 supercharges of the background geometry. They are described by a set of second order differential equations that we have found and analysed in a previous paper, where we studied 1/8 BPS states in the maximally supersymmetric AdS_5 x S^5 background. These geometries correspond to certain chiral primary operators of the N=1 superco...
Moduli spaces of AdS_5 vacua in N=2 supergravity
Louis, Jan
2016-01-01
We determine the conditions for maximally supersymmetric AdS_5 vacua of five-dimensional gauged N=2 supergravity coupled to vector-, tensor- and hypermultiplets charged under an arbitrary gauge group. In particular, we show that the unbroken gauge group of the AdS_5 vacua has to contain an U(1)_R-factor. Moreover we prove that the scalar deformations which preserve all supercharges form a Kahler submanifold of the ambient quaternionic Kahler manifold spanned by the scalars in the hypermultiplets.
Horizon Conformal Field Theories from $AdS_2$ Black Holes
Halyo, Edi
2015-01-01
We show that the very near horizon region of nonextreme black holes, which can be described by horizon CFTs, are related to $AdS_2$ Rindler spaces. The latter are $AdS_2$ black holes with specific masses and can be described by states of either $D=1$ or $D=2$ CFTs. The central charges of these CFTs and the conformal weights of their states that correspond to the nonextreme black holes exactly match those predicted by the horizon CFTs, providing supporting evidence for this description.
Double-trace deformations and entanglement entropy in AdS
Energy Technology Data Exchange (ETDEWEB)
Miyagawa, Taiki [Department of Physics, Kyoto University (Japan); Shiba, Noburo [Yukawa Institute for Theoretical Physics (YITP), Kyoto University (Japan); Takayanagi, Tadashi [Yukawa Institute for Theoretical Physics (YITP), Kyoto University (Japan); Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), University of Tokyo, Kashiwa, Chiba (Japan)
2016-01-15
We compute the bulk entanglement entropy of a massive scalar field in a Poincare AdS with the Dirichlet and Neumann boundary condition when we trace out a half space. Moreover, by taking into account the quantum back reaction to the minimal surface area, we calculate how much the entanglement entropy changes under a double-trace deformation of a holographic CFT. In the AdS3/CFT2 setup, our result agrees with the known result in 2d CFTs. In higher dimensions, our results offer holographic predictions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Double-Trace Deformations and Entanglement Entropy in AdS
Miyagawa, Taiki; Takayanagi, Tadashi
2016-01-01
We compute the bulk entanglement entropy of a massive scalar field in a Poincare AdS with the Dirichlet and Neumann boundary condition when we trace out a half space. Moreover, by taking into account the quantum back reaction to the minimal surface area, we calculate how much the entanglement entropy changes under a double-trace deformation of a holographic CFT. In the AdS3/CFT2 setup, our result agrees with the known result in 2d CFTs. In higher dimensions, our results offer holographic predictions.
Flowing along the edge: spinning up black holes in AdS spacetimes with test particles
Rocha, Jorge V
2014-01-01
We investigate the consequences of throwing point particles into odd-dimensional Myers-Perry black holes in asymptotically anti-de Sitter (AdS) backgrounds. We restrict our attention to the case in which the angular momenta of the background geometry are all equal. This process allows us to test the generalization of the weak cosmic censorship conjecture to asymptotically AdS spacetimes in higher dimensions. We find no evidence for overspinning in D = 5, 7, 9 and 11 dimensions. Instead, test particles carrying the maximum possible angular momentum that still fall into an extremal rotating black hole generate a flow along the curve of extremal solutions.
Integrable open spin-chains in AdS3/CFT2 correspondences
Prinsloo, Andrea(Department of Mathematics, University of Surrey, Guildford, GU2 7XH, United Kingdom); Regelskis, Vidas; Torrielli, Alessandro
2015-01-01
We study integrable open boundary conditions for d(2,1;\\alpha)^2 and psu(1,1|2)^2 spin-chains. Magnon excitations of these open spin-chains are mapped to massive excitations of type IIB open superstrings ending on D-branes in the AdS_3 x S^3 x S^3 x S^1 and AdS_3 x S^3 x T^4 supergravity geometries with pure R-R flux. We derive reflection matrix solutions of the boundary Yang-Baxter equation which intertwine representations of a variety of boundary coideal subalgebras of the bulk Hopf superal...
Three-α cluster state around 40Ca core
International Nuclear Information System (INIS)
We have studied three-α states around 40Ca based on a microscopic α-cluster model. Quite recently experimental evidence for such states has been obtained. This study was performed by introducing a Monte Carlo technique for the description of the THSR (Tohsaki Horiuchi Schuck Roepke) wave function, which is called the "virtual THSR" wave function. The three α cluster state around 40Ca has an energy below the Coulomb barrier top energy with a spatial extension comparable to the second 0+ state of 12C. There is possibility that such gas-like structure of α clusters is stabilized with geometric shape when valence neutrons are added. We also discussed the appearance of geometric α cluster configurations, especially for the linear chain configurations of three α clusters, in neutron-rich C isotopes. (author)
XPS study of CaO in sodium silicate glass
International Nuclear Information System (INIS)
This paper shows that CaO added to silicate glasses behaves much like Na2O in converting bridging oxygen sites to nonbridging sites. Good correspondence with model predictions was obtained but deviations were still sufficiently large to warrant attention. We speculate that some CaO may remain unreacted or that small-scale phase separation may occur. XPS core level shifts were monitored and possible charge-transfer effects were considered. Preliminary theoretical calculations utilizing a molecular-cluster approach were presented. XPS spectra for various glass compositions were simulated by appropriately combining local densities of state calculated for individual atoms. Dominant spectral features observed experimentally were found in the simulations. In conjunction with experiments, more carefully refined calculations will be subsequently examined. 7 figures
AdS/CFT correspondence: an overview
International Nuclear Information System (INIS)
Full text: A review on the AdS/CFT correspondence is presented. A gauge theory in d-dimensions and a gravity theory in (d+1)-dimensions can be related through the AdS/CFT correspondence in the name of the holography. In the precise limit of the correspondence, a strongly coupled gauge theory can be analyzed by a classical theory of gravity. This nonperturbative duality opens windows to access to strongly coupled systems. Starting by giving some basics of string theory, possible applications including QCD could be discussed. (author)
The Stylistic Analysis of car ads languages
Institute of Scientific and Technical Information of China (English)
张伟苹
2014-01-01
Automotive advertising language is mix of phonetics, vocabulary, rhetoric, syntax, and discourse language etc., and owning a strong promotional effect which can functioned as a bridge between language expression and promotion system for es-sential products and consumers. As a kind of the commercial advertising, car advertising with its own unique language features not only for product considerably, but also enriches the advertising language. In order to analysis the car ads, this article draws at-tention from the aspects of the phonetics, vocabulary, rhetoric and syntax features, and aims to get a further and better analysis or understanding of the car ads Languages.
Vehicular ad hoc network security and privacy
Lin, X
2015-01-01
Unlike any other book in this area, this book provides innovative solutions to security issues, making this book a must read for anyone working with or studying security measures. Vehicular Ad Hoc Network Security and Privacy mainly focuses on security and privacy issues related to vehicular communication systems. It begins with a comprehensive introduction to vehicular ad hoc network and its unique security threats and privacy concerns and then illustrates how to address those challenges in highly dynamic and large size wireless network environments from multiple perspectives. This book is richly illustrated with detailed designs and results for approaching security and privacy threats.
Issue ads and the health reform debate.
Bergan, Daniel; Risner, Genevieve
2012-06-01
The public debate over health care reform in 2009 was carried out partly through issue advertisements aired online and on television. Did these advertisements alter the course of the debate over health care reform? While millions of dollars are spent each year on issue ads, little is known about their effects. Results from a naturalistic online experiment on the effects of issue ads suggest that they can influence the perceived importance of an issue and perceptions of politicians associated with the featured policy while influencing policy support only among those low in political awareness. PMID:22323237
Ad hoc networks telecommunications and game theory
Benslama, Malek; Batatia, Hadj
2015-01-01
Random SALOHA and CSMA protocols that are used to access MAC in ad hoc networks are very small compared to the multiple and spontaneous use of the transmission channel. So they have low immunity to the problems of packet collisions. Indeed, the transmission time is the critical factor in the operation of such networks. The simulations demonstrate the positive impact of erasure codes on the throughput of the transmission in ad hoc networks. However, the network still suffers from the intermittency and volatility of its efficiency throughout its operation, and it switches quickly to the satura
iAd Production Beginner's Guide
Collier, Ben
2012-01-01
This beginner's guide focuses on getting you through all the major learning points in a smooth, logical order. You'll also see how to avoid some common pitfalls. This book is for brands, advertisers and developers who want to create compelling, emotive, iAd advertisements that generate revenue and increase brand awareness. You don't need previous experience of creating adverts or apps for iPhone and iPad, as you'll be taken through the entire process to make motion-rich, beautiful ads.
Adscape: Harvesting and Analyzing Online Display Ads
Barford, Paul; Canadi, Igor; Krushevskaja, Darja; Ma, Qiang; Muthukrishnan, S.
2014-01-01
Over the past decade, advertising has emerged as the primary source of revenue for many web sites and apps. In this paper we report a first-of-its-kind study that seeks to broadly understand the features, mechanisms and dynamics of display advertising on the web - i.e., the Adscape. Our study takes the perspective of users who are the targets of display ads shown on web sites. We develop a scalable crawling capability that enables us to gather the details of display ads including creatives an...
A new multistep Ca2+-Induced Cold Gelation Process for ß-Lactoglobulin
Veerman, C.; Baptist, H.G.M.; Sagis, L.M.C.; Linden, van der E.
2003-01-01
The objective of this study was to obtain -lactoglobulin (-lg) gels at very low protein concentrations using a new multistep Ca2+-induced cold gelation process. In the conventional cold gelation process, salt free -lg solutions were heated at neutral pH, cooled, and cross-linked by adding salts. In
KOOREMAN, PA; ENGBERTS, JBFN
1994-01-01
The synthesis, critical micelle concentrations (CMC) and Krafft temperatures (T(Krafft)) of a series of disodium 2-(sulfatomethyl)-1-alkylsulfates (2a-d) are presented, with alkyl being n-tetradecyl (C-14), n-hexadecyl (C-16), n-octadecyl (C18) and n-eicosyl(C20). The surfactants exhibit a large Ca2
Heat recovery from a thermal energy storage based on the Ca(OH)2/CaO cycle
International Nuclear Information System (INIS)
Thermal energy storage is very important in many applications related to the use of waste heat from industrial processes, renewable energies or from other sources. Thermochemical storage is very interesting for long-term storage as it can be carried out at room temperature with no energy losses. Dehydration/hydration cycle of Ca(OH)2/CaO has been applied for thermal energy storage in two types of reactors. One of them was a prototype designed by the authors, and in the other type conventional laboratory glassware was used. Parameters such as specific heats, reaction rate and enthalpy, mass losses and heat release were monitored during cycles. Although in the hydration step water is normally added in vapour phase, liquid water, at 0 deg. C has been used in these experiences. Results indicated that the energy storage system performance showed no significant differences, when we compared several hydration/dehydration cycles. The selected chemical reaction did not exhibit a complete reversibility because complete Ca(OH)2 dehydration, was not achieved. However the system could be used satisfactorily along 20 cycles at least. Heat recovery experiments showed general system behaviour during the hydration step in both types of reactors. The designed prototype was more efficient in this step. Main conclusions suggested carrying out one complete cycle at a higher dehydration temperature to recover total system reversibility. A modification of the prototype design trying to enhance heat transfer from the Ca(OH)2 bed could also be proposed
KWU-werkersklasdramas in Afrikaans (ca. 1930 - ca. 1950
Directory of Open Access Journals (Sweden)
J. L. Coetser
1999-05-01
Full Text Available GWU working class theatre in Afrikaans (ca. 1930 - ca. 1950In 1984 Elsabé Brink drew attention to plays, prose and poetry written between 1930 and 1950 in Afrikaans by members of the Garment Workers’ Union (GWU. Scholars such as Stander and Willemse (1992, Van Niekerk (1996 and Van Wyk (1995, 1997 have also referred to GWU plays. Apart from these overviews, GWU plays as such have not yet received the attention they deserve. This article presents a revaluation, initially by providing an overview of their contents, followed by an examination of cultural, economic and political influences. It is argued that - retrospectively - the GWU plays reflected a unique cultural specificity from the framework established by Sitas (1986 for more contemporary working class theatre.
Adding Users to the Website Design Process
Tomeo, Megan L.
2012-01-01
Alden Library began redesigning its website over a year ago. Throughout the redesign process the students, faculty, and staff that make up the user base were added to the conversation by utilizing several usability test methods. This article focuses on the usability testing conducted at Alden Library and delves into future usability testing, which…
Jansen, E. P. W. A.; Nieuwenhuis, A. F. M.
2013-01-01
Study success rates in higher education were already described in an article in Pedagogische Studien in 1959. Professor A.D. de Groot, internationally well-known by his research on Thought and choice in chess, analysed the success rate figures provided by Statistics Netherlands. Based on the differe
Fuel performance evaluation for ADS MYRRHA
International Nuclear Information System (INIS)
MYRRHA is an Accelerator Driven System (ADS) under development at Mol in Belgium and aiming to serve as a basis for the European experimental ADS to provide protons and neutrons for various applications. It consists of a proton accelerator delivering a 350 MeV*5 mA proton beam to a liquid Pb-Bi spallation target that in turn couples to a Pb-Bi cooled, subcritical fast core. A preliminary design of the experimental fuel rods and analysis of their performance under typical ADS conditions is a first step of the fuel development program. Different designs are to be studied and different kinds of fuels are expected to be tested. In the current design, (U,Pu)O2 MOX fuel with the enrichment of 20-30 wt.% of Pu is considered to be a basis of the subcritical core, whereas different sorts of experimental fuel rods should be tested in the experimental channels to study minor actinides and low-lived fission products transmutation. In a later phase, a part of the MOX fuel in the subcritical core will be replaced with non-uranium fuels with transuranium elements. In the present report some result of modelling of the behaviour of two experimental rods (one with MOX and another with IMF) in the hottest fuel assembly of the ADS MYRRHA - are presented. (author)
CERN Enters the Second Year AD
2001-01-01
2001 is the year that physics at CERN's new Antiproton Decelerator (AD) really gets up to speed. Changes to the AD since 2000 mean that this year the three experiments, ASACUSA, ATHENA, and ATRAP have had more intense antiproton beams to work with since physics started on 7 May. CERN's Antiproton Decelerator - major improvements for 2001. The AD is a unique machine. Its job is to decelerate not accelerate particle beams, and it has to handle beam energies that vary by an unprecedented factor of 35 from injection to ejection. Since the machine was designed to operate at fixed energy in its first incarnation as a collector of antiprotons for CERN's 1980s proton antiproton collider, this factor of 35 presented a big challenge to the AD team. The team's design goal was to hang onto a quarter of the injected antiprotons through their vertiginous fall in energy, and to repeat the deceleration cycle once per minute. Improvements to the machine over the winter shutdown and through the first four weeks of 2001 run...
Added value: The differences that count
Directory of Open Access Journals (Sweden)
Dominique Bouchet
2012-08-01
Full Text Available Clinging to a simplistic conceptualization of the concept of added value might impair our capability to develop insights to what really matters today when companies seek to make differences within the global market. Today it is more necessary than ever to take into account the importance of language and culture as competitive factors.
Enhanced Wireless Network Ad Hoc Pattern
Directory of Open Access Journals (Sweden)
M. Kamalakannan
2012-06-01
Full Text Available Early simulation experience with wireless ad hoc networks suggests that their capacity can be surprisingly low, due to the requirement that nodes forward each others’ packets. The achievable capacity depends on network size, traffic patterns and detailed local radio interactions. This study examines these factors alone and in combination, using simulation and analysis from first principles. Our results include both specific constants and general relationship Scaling helpful in understanding the limitations of wireless ad hoc networks. We examine interactions of the 802.11 MAC and ad hoc forwarding and the effect on capacity for several simple configurations and traffic patterns. While 802.11 discovers reasonably good schedules, we nonetheless observe capacities markedly less than optimal for very simple chain and lattice networks with very regular traffic patterns. We validate some simulation results with experiments. We also show that the traffic pattern determines whether an ad hoc network’s per node capacity will scale to large networks. In particular, we show that for total capacity to scale up with network size the average distance between source and destination nodes must remain small as the network grows. Nonlocal traffic patterns in which this average distance grows with the network size result in a rapid decrease of per node capacity.
Y-system for form factors at strong coupling in AdS5 and with multi-operator insertions in AdS3
Gao, Zhiquan; Yang, Gang
2013-06-01
We study form factors in {N}=4 SYM at strong coupling in general kinematics and with multi-operator insertions by using gauge/string duality and integrability techniques. This generalizes the AdS3 results of Maldacena and Zhiboedov in two non-trivial aspects. The first generalization to AdS5 space was motivated by its potential connection to strong coupling Higgs-to-three-gluons amplitudes in QCD which was observed recently at weak coupling. The second generalization to multi-operator insertions was motivated as a step towards applying on-shell techniques to compute correlation functions at strong coupling. In this picture, each operator is associated to a monodromy condition on the cusp solutions. We construct Y-systems for both cases. The Y -functions are related to the spacetime (cross) ratios. Their WKB approximations based on a rational function P ( z) are also studied. We focus on the short operators, while the prescription is hopefully also applicable for more general operators.
Double Thermalization via AdS/CFT
Ali-Akbari, M; Kishani-Farahani, A; Shafie, N
2016-01-01
We exploit the AdS/CFT correspondence to investigate thermalization in an N=2 strongly coupled gauge theory including massless fundamental matter (quark). More precisely, we consider the response of a zero temperature state of the gauge theory under variation of an external electric field leading to a time-dependent current. The holographic dual of the above set-up is given by introducing a time-dependent electric field on the probe D7-brane embedded in an AdS_5 X S^5 background. In the dual gravity theory, due to a time-dependent electric field an apparent horizon forms on the brane which, according to AdS/CFT dictionary, is the counterpart of the thermalization process in the gauge theory. We classify different functions for time-dependent electric field and study their effect on the apparent horizon formation. In the case of pulse functions where the electric field varies from zero to zero, apart from non-equilibrium phase, we observe that two apparent horizons form on the brane. On the gauge theory side, ...
Amiri-Sharifi, S.; Ali-Akbari, M.; Kishani-Farahani, A.; Shafie, N.
2016-08-01
We exploit the AdS/CFT correspondence to investigate thermalization in an N = 2 strongly coupled gauge theory including massless fundamental matter (quark). More precisely, we consider the response of a zero temperature state of the gauge theory under influence of an external electric field which leads to a time-dependent current. The holographic dual of the above set-up is given by introducing a time-dependent electric field on the probe D7-brane embedded in an AdS5 ×S5 background. In the dual gravity theory an apparent horizon forms on the brane which, according to AdS/CFT dictionary, is the counterpart of the thermalization process in the gauge theory side. We classify different functions for time-dependent electric field and study their effect on the apparent horizon formation. In the case of pulse functions, where the electric field varies from zero to zero, apart from non-equilibrium phase, we observe the formation of two separate apparent horizons on the brane. This means that the state of the gauge theory experiences two different temperature regimes during its time evolution.
AdS/CFT correspondence and supersymmetry
International Nuclear Information System (INIS)
We use the group-theoretic interpretation of the AdS/CFT correspondence which we proposed earlier in order to lift intertwining operators acting between boundary conformal representations to intertwining operators acting between bulk conformal representations. Further, we present the classification of the positive energy (lowest weight) unitary irreducible representations of the D=6 superconformal algebras osp(8*/2N). (author)
de Leeuw, Marius; Moriyama, Sanefumi; Regelskis, Vidas; Torrielli, Alessandro
2012-01-01
We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.
ENEA presenta sistema ADS per trattamento scorie
2002-01-01
"Arriva il sistema Ads (Accelerator driven system) per il trattamento dei rifiuti radioattivi. Lo studio di fattibilita' per l' innovativa tecnologia, realizzato da un gruppo di lavoro congiunto Enea, Cea, Cern e Ansaldo, e' stato presentato oggi nel corso di un workshop presieduto dal premio Nobel per la fisica, Carlo Rubbia" (1/2 page).
Holzscheiter, M H
2014-01-01
After 7 years running the AD-4 Experiment at antiproton momentum of 502 MeV/c we have now assembled a complete data set and are preparing to combine all years into a single analysis of RBE vs. Depth for an antiproton beam stopping in water. We describe experimental challenges and computational issues which need to be resolved to achieve this final step.
施磷肥对土壤中Ca^2＋吸持特征的影响%Effects of P Fertilization on the Ca^2+ Retention Characteristics in Soil
Institute of Scientific and Technical Information of China (English)
张大庚; 贺云龙; 栗杰; 依艳丽; 刘敏霞
2012-01-01
以辽宁省典型耕地土壤（棕壤和褐土）为研究对象,在研究土壤Ca2＋释放和Ca2＋等温吸持的基础上,系统研究不同pH条件下施磷肥对土壤Ca2＋吸持特征的影响。结果表明：棕壤和褐土中Ca2＋在2h左右为快速释放阶段,Ca2＋的释放量为褐土〉棕壤,而释放率为褐土〈棕壤。褐土对Ca2＋的吸持能力要大于棕壤;随电解质溶液pH值增加,磷肥的添加明显增加了Ca2＋的沉淀量;当加磷肥量相同时,加入PO34-后Ca2＋的沉淀量高于HPO24-;随加磷肥量增加,加入PO34-或HPO24-与Ca2＋形成的沉淀量均增加。随着电解质溶液pH值的升高,土壤对Ca2＋的吸持量增加,但与对照相比增加的倍数下降。pH值对土壤吸持Ca2＋的影响为棕壤〉褐土,添加HPO24-〉添加PO34-。%Typical cultivation soils of brown earth and cinnamon soil were taken as the research objects,Liaoning province.On the basis of the research of Ca2+ releasing and the isothermal adsorption,the paper studied the effects of P fertilization on Ca2+ absorption characteristics in soil under different pH.The results show that Ca2+ releasing was quick in 2 h in brown earth and cinnamon soil.Ca2+ releasing quantity was brown earth cinnamon soil and releasing rate was brown earth cinnamon soil.The adsorption ability of Ca2+ was brown earth cinnamon soil.With the increase of the solution pH value,the phosphorus added to solution significantly increased the amount of precipitation Ca2+.When the phosphorus added to solution was same in quantity,precipitation weight generating between PO3-4 and Ca2+ was higher than that generating between HPO2-4 and Ca2+.With the amount of phosphorus added to solution increasing,precipitation weight generating between PO3-4 or HPO2-4and Ca2+ increased.With the rise of electrolyte solution pH value,Ca2+ adsorption to soil increased,but the percentage increased in decline comparing with the control.The effect of pH value on the adsorption Ca2
Effect of CaO from Mineral and Pure Oxide on Nano structure Cordierite
International Nuclear Information System (INIS)
Cordierite was synthesized via glass-route using mineral and pure oxide material. Kaolin, talc, dolomite, magnesia, alumina, silica, and calcium oxide were mixed and melted at 1540 degree Celsius for 4 h. CaO from mineral and pure oxide was added in order to investigate the properties of each material in cordierite system. Sample was characterized using XRD analysis, dilatometer testing and SEM. XRD result shows that when 5 wt % CaO from mineral (C5 Min) was added and sintered at 900 degree Celsius, α-cordierite exist as major phase and anorthite as a minor phase. While for a sample consists of 5 wt % CaO from pure oxide (C5 Ox), α-cordierite was present as major phases α-cordierite and anorthite as minor phases. Crystallite sizes of each material were in nano range and crystallite size of C5 Ox was less than C5 Min. (author)
Time-dependent flow from an AdS Schwarzschild black hole
International Nuclear Information System (INIS)
I discuss two examples of time-dependent flow which can be described in terms of an AdS Schwarzschild black hole via holography. The first example involves Bjorken hydrodynamics which should be applicable to the formation of the quark gluon plasma in heavy ion collisions. The second example is the cosmological evolution of our Universe
F-string Solution in AdS4 X CP3 PP-wave Background
Banerjee, Gourav
2016-01-01
We present supergravity solution for F-string in pp wave background obtained from AdS4 X CP3 with zero flat directions.The classical solution is shown to break all space-time supersymmetries. We explicitly write down the standard as well as supernumerary Killing spinors both for the background and F-string solution.
Near horizon data and physical charges of extremal AdS black holes
Astefanesei, D.; Banerjee, N.; Dutta, S.
2011-01-01
We compute the physical charges and discuss the properties of a large class of five-dimensional extremal AdS black holes by using the near horizon data. Our examples include baryonic and electromagnetic black branes, as well as supersymmetric spinning black holes. In the presence of the gauge Chern–
The Complexity of Identifying Ryu-Takayanagi Surfaces in AdS3/CFT2
Bao, Ning
2016-01-01
We present a constructive algorithm for the determination of Ryu-Takayanagi surfaces in AdS3/CFT2 which exploits previously noted connections between holographic entanglement entropy and max-flow/min-cut. We then characterize its complexity as a polynomial time algorithm.
An alternative perspective to observe the critical phenomena of dilaton AdS black holes
Mo, Jie-Xiong
2016-01-01
The critical phenomena of dilaton AdS black holes are probed from a totally different perspective other than the $P-v$ criticality and the $q-U$ criticality discussed in the former literature. We investigate not only the two point correlation function but also the entanglement entropy of dilaton AdS black holes. We achieve this goal by solving the equation of motion constrained by the boundary condition numerically and we concentrate on $\\delta L$ and $\\delta S$ which have been regularized by subtracting the terms in pure AdS with the same boundary region. For both the two point correlation function and the entanglement entropy, we consider $4\\times2\\times2=16$ cases due to different choices of parameters. The van der Waals like behavior can be clearly witnessed from all the $T-\\delta L$ ($T-\\delta S$) graphs for $q
Charged and rotating AdS black holes and their CFT duals
Hawking, Stephen William
2000-01-01
Black hole solutions that are asymptotic to $ AdS_5 \\times S^5$ or $ AdS_4 then one can obtain a Reissner-Nordstrom-AdS black hole. If the asymptotically AdS space rotates then one can obtain a Kerr-AdS hole. One might expect superradiant scattering to be possible in either of these cases. Superradiant modes reflected off the potential barrier outside the hole would be re-amplified at the horizon, and a classical instability would result. We point out that the existence of a Killing vector field timelike everywhere outside the horizon prevents this from occurring for black holes with negative action. Such black holes are also thermodynamically stable in the grand canonical ensemble. The CFT duals of these black holes correspond to a theory in an Einstein universe with a chemical potential and a theory in a rotating Einstein universe. We study these CFTs in the zero coupling limit. In the first case, Bose-Einstein condensation occurs on the boundary at a critical value of the chemical potential. However the su...
The boundary S-matrix and the AdS to CFT dictionary
Giddings, Steven B
1999-01-01
An S-matrix is defined for anti-de Sitter space by constructing ``in'' and ``out'' states that asymptote to the timelike boundary. An analog of the LSZ formula shows that this boundary S-matrix is given directly by correlation functions in the boundary conformal theory. This provides a key entry in the AdS to CFT dictionary.
Entropy of near-extremal black holes in AdS_5
V. Balasubramanian; J. de Boer; V. Jejjala; J. Simón
2008-01-01
We construct the microstates of near-extremal black holes in AdS_5 x S^5 as gases of defects distributed in heavy BPS operators in the dual SU(N) Yang-Mills theory. These defects describe open strings on spherical D3-branes in the S^5, and we show that they dominate the entropy by directly enumerati
On Critical Massive (Super)Gravity in adS3
Bergshoeff, Eric A.; Hohm, Olaf; Rosseel, Jan; Sezgin, Ergin; Townsend, Paul K.
2011-01-01
We review the status of three-dimensional “general massive gravity” (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of “chiral gravity”. We then show how these results extend to N = 1 super-GMG, expanded about
On Critical Massive (Super)Gravity in adS(3)
Bergshoeff, Eric A.; Hohm, Olaf; Rosseel, Jan; Sezgin, Ergin; Townsend, Paul K.; Aldaya,; Barcelo, C; Jaramillo, JL
2011-01-01
We review the status of three-dimensional "general massive gravity" (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of "chiral gravity". We then show how these results extend to,N = 1 super-GMG, expanded about
String in AdS black hole: A thermo field dynamic approach
Cantcheff, M. Botta; Gadelha, Alexandre L.; Marchioro, Dáfni F. Z.; Nedel, Daniel Luiz
2012-10-01
Based on Maldacena’s description of an eternal anti-de Sitter (AdS) black hole, we reassess the thermo field dynamics (TFD) formalism in the context of the AdS/CFT correspondence. The model studied here involves the maximally extended AdS-Schwarschild solution and two (noninteracting) copies of the conformal field theory (CFT) associated to the global AdS spacetime, along with an extension of the string by imposing natural gluing conditions in the horizon. We show that the gluing conditions in the horizon define a string boundary state which is identified with the TFD thermal vacuum, globally defined in the Kruskal extension of the AdS black hole. We emphasize the connection of this picture with unitary SU(1,1) TFD formulation, and we show that information about the bulk and the conformal boundary is present in the SU(1,1) parameters. Using the unitary SU(1,1) TFD formulation, a canonical prescription for calculating the world sheet real time thermal Green’s function is made, and the entropy associated with the entanglement of the two CFT’s is calculated.
Thermal String Vacuum in Black-Hole AdS Spacetime
Graça, E L
2005-01-01
In this letter we propose a new ansatz for the thermal string in the TFD formulation. From it, we derive the thermal vacuum for the closed bosonic string and calculate the thermal partition function in the blackhole $AdS$ background in the first order of the perturbative quantization.
Exact N=4 correlators of AdS3/CFT2
International Nuclear Information System (INIS)
We extend to chiral N=4 operators the holographic agreement recently found between correlators of the symmetric orbifold of M4 at large N and type IIB strings propagating in AdS3xS3xM4, where M4=T4 or K3. We also present expressions for some bulk correlators not yet computed in the boundary
Holographic Renormalization for z=2 Lifshitz Space-Times from AdS
Chemissany, Wissam; Hartong, Jelle; Rollier, Blaise
2012-01-01
Lifshitz space-times with critical exponent z=2 can be obtained by dimensional reduction of Schroedinger space-times with critical exponent z=0. The latter space-times are asymptotically AdS solutions of AdS gravity coupled to an axion-dilaton system and can be uplifted to solutions of type IIB supergravity. This basic observation is used to perform holographic renormalization for 4-dimensional asymptotically z=2 locally Lifshitz space-times by Scherk-Schwarz dimensional reduction of the corresponding problem of holographic renormalization for 5-dimensional asymptotically locally AdS space-times coupled to an axion-dilaton system. We can thus define and characterize a 4-dimensional asymptotically locally z=2 Lifshitz space-time in terms of 5-dimensional AdS boundary data. In this setup the 4-dimensional structure of the Fefferman-Graham expansion and the structure of the counterterm action, including the scale anomaly, will be discussed. We find that for asymptotically locally z=2 Lifshitz space-times obtaine...
Warped AdS near-horizon geometry of completely localized intersections of M5-branes
International Nuclear Information System (INIS)
We study a Hanany-Witten set-up relevant to N = 2 superconformal field theories. We find the exact near-horizon solution for this 11-dimensional system which involves intersecting M5-branes. The metric describes a warped product of AdS5 with a manifold with SU(2)xU(1) isometry. (author)
Correction terms to Newton law due to induced gravity in AdS background
International Nuclear Information System (INIS)
We calculate small correction terms to gravitational potential on Randall-Sundrum brane with an induced Einstein term. The behaviors of the correction terms depend on the magnitudes of AdS radius k-1 and a characteristic length scale λ of model. We present the gravitational potential for arbitrary k and λ at all distances
Institute of Scientific and Technical Information of China (English)
ZHANG Ye; Michael G. Irwin; LI Rui; CHEN Zhiwu; Tak-Ming Wong
2009-01-01
Background Preconditioning with remifentanil confers cardioprotection. Since Ca2+ overload is a precipitating factor of injury, we determined the effects of remefentanil on intracellular Ca2+ ([Ca2+]I) and its transients induced by electrical stimulation and caffeine, which reflects Ca2+ handling by Ca2+ handling proteins, in rat ventricular myocytes. Methods Freshly isolated adult male Sprague-Dawley rat myocytes were loaded with Fura-2/AM and [Ca]I was determined by spectrofluorometry. Remifentanil at 0.1-1000 μg/L was administered. Ten minutes after administration, either 0.2 Hz electrical stimulation was applied or 10 mmol/L caffeine was added. The [Ca2+]I, and the amplitude, time resting and 50% decay (t50) of both transients induced by electrical stimulation (E[Ca2+]I) and caffeine (C[Ca2+]I) were determined.Results Remifentanil (0.1-1000.0 μg/L) decreased the [Ca2+]I in a dose-dependent manner. It also decreased the amplitude of both transients dose-dependently. Furthermore, it increased the time to peak and t50 of both transients dose-dependently.Conclusion Remifentanil reduced the [Ca2+]I and suppressed the transients induced by electrical stimulation and caffeine in rat ventricular myocytes.
Designing added functions in engineered cementitious composites
Yang, En-Hua
In this dissertation, a new and systematic material design approach is developed for ECC with added functions through material microstructures linkage to composite macroscopic behavior. The thesis research embodies theoretical development by building on previous ECC micromechanical models, and experimental investigations into three specific new versions of ECC with added functions aimed at addressing societal demands of our built infrastructure. Specifically, the theoretical study includes three important ECC modeling elements: Steady-state crack propagation analyses and simulation, predictive accuracy of the fiber bridging constitutive model, and development of the rate-dependent strain-hardening criteria. The first element establishes the steady-state cracking criterion as a fundamental requirement for multiple cracking behavior in brittle matrix composites. The second element improves the accuracy of crack-width prediction in ECC. The third element establishes the micromechanics basis for impact-resistant ECC design. Three new ECCs with added functions were developed and experimentally verified in this thesis research through the enhanced theoretical framework. A green ECC incorporating a large volume of industrial waste was demonstrated to possess reduced crack width and drying shrinkage. The self-healing ECC designed with tight crack width was demonstrated to recover transport and mechanical properties after microcrack damage when exposed to wet and dry cycles. The impact-resistant ECC was demonstrated to retain tensile ductility with increased strength under moderately high strain-rate loading. These new versions of ECC with added functions are expected to contribute greatly to enhancing the sustainability, durability, and safety of civil infrastructure built with ECC. This research establishes the effectiveness of micromechanics-based design and material ingredient tailoring for ECC with added new attributes but without losing its basic tensile ductile
Inhibitors of the Ca2+/calmodulin-dependent protein kinase phosphatase family (CaMKP and CaMKP-N)
International Nuclear Information System (INIS)
Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP) and its nuclear isoform CaMKP-N are unique Ser/Thr protein phosphatases that negatively regulate the Ca2+/calmodulin-dependent protein kinase (CaMK) cascade by dephosphorylating multifunctional CaMKI, II, and IV. However, the lack of specific inhibitors of these phosphatases has hampered studies on these enzymes in vivo. In an attempt to obtain specific inhibitors, we searched inhibitory compounds and found that Evans Blue and Chicago Sky Blue 6B served as effective inhibitors for CaMKP. These compounds also inhibited CaMKP-N, but inhibited neither protein phosphatase 2C, another member of PPM family phosphatase, nor calcineurin, a typical PPP family phosphatase. The minimum structure required for the inhibition was 1-amino-8-naphthol-4-sulfonic acid. When Neuro2a cells cotransfected with CaMKIV and CaMKP-N were treated with these compounds, the dephosphorylation of CaMKIV was strongly suppressed, suggesting that these compounds could be used as potent inhibitors of CaMKP and CaMKP-N in vivo as well as in vitro
Black hole formation in AdS and thermalization on the boundary
International Nuclear Information System (INIS)
We investigate black hole formation by a spherically collapsing thin shell of matter in AdS space. This process has been suggested to have a holographic interpretation as thermalization of the CFT on the boundary of the AdS space. The AdS/CFT duality relates the shell in the bulk to an off-equilibrium state of the boundary theory which evolves towards a thermal equilibrium when the shell collapses to a black hole. We use 2-point functions to obtain information about the spectrum of excitations in the off-equilibrium state, and discuss how it characterizes the approach towards thermal equilibrium. The full holographic interpretation of the gravitational collapse would require a kinetic theory of the CFT at strong coupling. We speculate that the kinetic equations should be interpreted as a holographic dual of the equation of motion of the collapsing shell. (author)
Comment on three-point function in AdS(3)/CFT(2)
Giribet, Gaston
2008-01-01
Recently, exact agreement has been found between bulk and boundary three-point functions in AdS_3 x S^3 x T^4 with NSNS fluxes. This represents a non-trivial check of AdS/CFT correspondence beyond the supergravity approximation as it corresponds to an exact worldsheet computation. When taking a closer look at this computation, one notices that a crucial point for the bulk-boundary agreement to hold is an intriguing mutual cancellation between worldsheet contributions corresponding to the AdS_3 and to the S^3 pieces of the geometry, what results in a simple factorized form for the final three-point function. In this note we review this cancellation and clarify some points about the analytic relation between the SU(2) and the SL(2,R) structure constants. In particular, we dicuss the connection to the Coulomb gas representation. We also make some comments on the four-point function.
Effects of dark energy on P–V criticality of charged AdS black holes
International Nuclear Information System (INIS)
In this Letter, we investigate the effects of dark energy on P–V criticality of charged AdS black holes by considering the case of the RN-AdS black holes surrounded by quintessence. By treating the cosmological constant as thermodynamic pressure, we study its thermodynamics in the extended phase space. It is shown that quintessence dark energy does not affect the existence of small/large black hole phase transition. For the case ωq=−2/3 we derive analytic expressions of critical physical quantities, while for cases ωq≠−2/3 we appeal to numerical method for help. It is shown that quintessence dark energy affects the critical physical quantities near the critical point. Critical exponents are also calculated. They are exactly the same as those obtained before for arbitrary other AdS black holes, which implies that quintessence dark energy does not change the critical exponents
Holographic Thermalization, Stability of AdS, and the FPU Paradox
Balasubramanian, Venkat; Green, Stephen R; Lehner, Luis; Liebling, Steven L
2014-01-01
For a real massless scalar field in general relativity with a negative cosmological constant, we uncover a large class of spherically symmetric initial conditions that are close to AdS, but whose numerical evolution does not result in black hole formation. According to the AdS/CFT dictionary, these bulk solutions are dual to states of a strongly interacting boundary CFT that fail to thermalize at late times. Furthermore, as these states are not stationary, they define dynamical CFT configurations that do not equilibrate. We develop a two-timescale perturbative formalism that captures both direct and inverse cascades of energy and agrees with our fully nonlinear evolutions in the appropriate regime. We also show that this formalism admits a large class of quasi-periodic solutions. Finally, we demonstrate a striking parallel between the dynamics of AdS and the classic Fermi-Pasta-Ulam-Tsingou problem.
Hairy Black Holes in AdS$_5\\times S^5$
Markeviciute, J
2016-01-01
We use numerical methods to exhaustively study a novel family of hairy black hole solutions in AdS$_5$. These solutions can be uplifted to solutions of type IIB supergravity with AdS$_5\\times S^5$ asymptotics and are thus expected to play an important role in our understanding of AdS/CFT. We find an intricate phase diagram, with the aforementioned family of hairy black hole solutions branching from the Reissner-Nordstr\\"om black hole at the onset of the superradiance instability. We analyse black holes with spherical and planar horizon topology and explain how they connect in the phase diagram. Finally, we detail their global and local thermodynamic stability across several ensembles.
Black Hole Formation in AdS Einstein-Gauss-Bonnet Gravity
Deppe, Nils; Frey, Andrew R; Kunstatter, Gabor
2016-01-01
AdS spacetime has been shown numerically to be unstable against a large class of arbitrarily small perturbations. In arXiv:1410.1869, the authors presented a preliminary study of the effects on stability of changing the local dynamics by adding a Gauss-Bonnet term to the Einstein action. Here we provide further details as well as new results with improved numerical methods. In particular, we elucidate new structure in Choptuik scaling plots. We also provide evidence of chaotic behavior at the transition between immediate horizon formation and horizon formation after the matter pulse reflects from the AdS conformal boundary. Finally, we present data suggesting the formation of naked singularities in spacetimes with ADM mass below the algebraic bound for black hole formation.
Bruno, Claudio; Cavalluzzi, Maria Maddalena; Rusciano, Maria Rosaria; Lovece, Angelo; Carrieri, Antonio; Pracella, Riccardo; Giannuzzi, Giulia; Polimeno, Lorenzo; Viale, Maurizio; Illario, Maddalena; Franchini, Carlo; Lentini, Giovanni
2016-06-30
An affinity capillary electrophoresis (ACE) method to estimate apparent dissociation constants between bovine brain calmodulin (CaM) and non-peptidic ligands was developed. The method was validated reproducing the dissociation constants of a number of well-known CaM ligands. In particular, the potent antagonist 125-C9 was ad hoc synthesized through an improved synthetic procedure. The ACE method was successfully applied to verify CaM affinity for lubeluzole, a well-known neuroprotective agent recently proved useful to potentiate the activity of anti-cancer drugs. Lubeluzole was slightly less potent than 125-C9 (Kd = 2.9 ± 0.7 and 0.47 ± 0.06 μM, respectively) and displayed Ca(2+)/calmodulin-dependent kinase II (CaMKII) inhibition (IC50 = 40 ± 1 μM). Possible binding modes of lubeluzole to CaM were explored by docking studies based on the X-ray crystal structures of several trifluoperazine-CaM complexes. An estimated dissociation constant in good agreement with the experimental one was found and the main aminoacidic residues and interactions contributing to complex formation were highlighted. The possibility that interference with Ca(2+) pathways may contribute to the previously observed chemosensitizing effects of lubeluzole on human ovarian adenocarcinoma and lung carcinoma cells are discussed. PMID:27043269
Localization of 45Ca and 36Cl in fruit tissue of apples after post harvest dipping
International Nuclear Information System (INIS)
Apples of 'Cox's Orange Pippin' and 'Golden Delicious' were post-harvest dipped (2% CaCl2 + 0.3% Keltrol) to study the translocation and deposit of Ca and of Cl in the fruit. Macroautoradiographic studies showed that both ions easily penetrated into the fruit increasingly with time of storage, but that they were distributed differently: After 3 months of storage Ca was found in all parts of the fruit, more pronounced so in the vascular tissue and cortex, contrary to Cl, which mainly accumulated in the cortex tissue. In the area of the calyx and stem end penetration was markedly enhanced. After external application of Ca and other multivalent cations the endogenous fruit Ca was partly translocated into the tissue below. Efflux and exchange experiments with fruit tissue in hypertonic solution showed that 5-10% of the Ca deposited in the cortex after post-harvest dipping was removed within 5 h; however, with addition of EDTA to the solution, more than 80% exchanged. Contrarily, the rate of Cl efflux and that of monovalent cations (K,Na) was only half the amount, independent whether the complexing agent was added to the solution or not. Likewise 64-72% of the Ca deposited after natural transport into the fruit, could be exchanged. After supply of 1 mM 45CaCl2 in hypertonic solution substantial amounts of Ca were absorbed by the fruit tissue, but even after an exchange period with EDTA a remarkable portion was retained. The investigations underline the importance of the high cation binding capacity of the fruit tissue in the region of the membrane and cell wall with respect to the function of Ca. Furthermore, it was shown that the Ca companion ion, Cl, has to be included into the considerations. (orig./MG)
Synthesis of studies for ADS development
International Nuclear Information System (INIS)
One goal of the December 1991 law is the exploration of the separation-transmutation means to reduce the impact of minor actinides in high-level radioactive wastes. By 2040, the fourth generation of fast neutron reactors would be capable to entirely recycle their wastes and those previously generated. In the case of a delayed implementation of this type of reactor, a 'double-stratum' scenario foresees the recycling of plutonium in PWR-Mox reactors and the recycling of minor actinides in reactors dedicated to transmutation. The accelerator-driven systems (ADS) are well-adapted for this task and the share of such systems in the nuclear park would represent only 5 to 10% of the overall power. In this note, the technical data of this scenario and the physics of ADS are recalled first. Then, the status of researches in progress, the technological advances and the researches to carry on in the different domains are presented: nuclear data, in particular those linked with spallation phenomena; power accelerators, in particular the works in progress to warrant their reliability and maneuverability; spallation targets, in particular the Megapie experiment with a liquid lead-bismuth target submitted to a powerful proton beam and researches on the related materials technology; the fuels specific to transmutation with no uranium (replaced by an inert support); the project of subcritical facilities studied in the framework of the PDS-XADS European project (first design schemes of gas or lead-bismuth cooled subcritical reactors); the subcritical reactor physics, in particular the joint CNRS-CEA Muse program which has led to the construction of the very first ADS for the testing of measurement and reactivity control methods. Thanks to these studies carried out since about a decade, the design and part of the qualification of the elementary parts (accelerator, target, core) of ADS have made lot of progress. The PDS-XADS studies did not show any incompatibility of ADS principle for
Calibration of the AD-RICE 2012 model
de Bruin, Kelly
2015-01-01
The AD-RICE2012 model is an updated version of the AD-RICE99 (Nordhaus and Boyer 2001) model, where the AD_RICE99 model is based on the RICE99 model and the AD-RICE2012 on the RICE2010 (Nordhaus 2010) model. In this document, we will describe the calibration of the AD-RICE2012 model and compare it with the AD-RICE99 model.
Evaporation of large black holes in AdS: coupling to the evaporon
International Nuclear Information System (INIS)
Large black holes in an asymptotically AdS spacetime have a dual description in terms of approximately thermal states in the boundary CFT. The reflecting boundary conditions of AdS prevent such black holes from evaporating completely. On the other hand, the formulation of the information paradox becomes more stringent when a black hole is allowed to evaporate. In order to address the information loss problem from the AdS/CFT perspective we then need the boundary to become partially absorptive. We present a simple model that produces the necessary changes on the boundary by coupling a bulk scalar field to the evaporon, an external field propagating in one extra spatial dimension. The interaction is localized at the boundary of AdS and leads to partial transmission into the additional space. The transmission coefficient is computed in the planar limit and perturbatively in the coupling constant. Evaporation of the large black hole corresponds to cooling down the CFT by transferring energy to an external sector.
Euclidean Wilson loops and minimal area surfaces in lorentzian AdS 3
Irrgang, Andrew; Kruczenski, Martin
2015-12-01
The AdS/CFT correspondence relates Wilson loops in N=4 SYM theory to minimal area surfaces in AdS 5 × S 5 space. If the Wilson loop is Euclidean and confined to a plane ( t, x) then the dual surface is Euclidean and lives in Lorentzian AdS 3 ⊂ AdS 5. In this paper we study such minimal area surfaces generalizing previous results obtained in the Euclidean case. Since the surfaces we consider have the topology of a disk, the holonomy of the flat current vanishes which is equivalent to the condition that a certain boundary Schrödinger equation has all its solutions anti-periodic. If the potential for that Schrödinger equation is found then reconstructing the surface and finding the area become simpler. In particular we write a formula for the Area in terms of the Schwarzian derivative of the contour. Finally an infinite parameter family of analytical solutions using Riemann Theta functions is described. In this case, both the area and the shape of the surface are given analytically and used to check the previous results.
String in AdS Black Hole: A Thermo Field Dynamic Approach
Cantcheff, M Botta; Marchioro, Dafni F Z; Nedel, Daniel Luiz
2012-01-01
Based on Maldacena's description of an eternal AdS-black hole, we reassess the Thermo Field Dynamics (TFD) formalism in the context of the AdS/CFT correspondence. The model studied here involves the maximally extended AdS-Schwarschild solution and two (non-interacting) copies of the CFT associated to the global AdS spacetime, along with an extension of the string by imposing natural gluing conditions in the horizon. We show that the gluing conditions in the horizon define a string boundary state which is identified with the TFD thermal vacuum, globally defined in the Kruskal extension of the AdS black hole. We emphasize the connection of this picture with unitary SU(1,1) TFD formulation and we show that information about the bulk and the conformal boundary is present in the SU(1,1) parameters. Using the unitary SU(1,1) TFD formulation, a canonical prescription for calculating the worldsheet real time thermal Green's function is made and the entropy associated with the entanglement of the two CFT's is calculat...
Holographic Rényi entropy in AdS3/LCFT2 correspondence
International Nuclear Information System (INIS)
The recent study in AdS3/CFT2 correspondence shows that the tree level contribution and 1-loop correction of holographic Rényi entanglement entropy (HRE) exactly match the direct CFT computation in the large central charge limit. This allows the Rényi entanglement entropy to be a new window to study the AdS/CFT correspondence. In this paper we generalize the study of Rényi entanglement entropy in pure AdS3 gravity to the massive gravity theories at the critical points. For the cosmological topological massive gravity (CTMG), the dual conformal field theory (CFT) could be a chiral conformal field theory or a logarithmic conformal field theory (LCFT), depending on the asymptotic boundary conditions imposed. In both cases, by studying the short interval expansion of the Rényi entanglement entropy of two disjoint intervals with small cross ratio x, we find that the classical and 1-loop HRE are in exact match with the CFT results, up to order x6. To this order, the difference between the massless graviton and logarithmic mode can be seen clearly. Moreover, for the cosmological new massive gravity (CNMG) at critical point, which could be dual to a logarithmic CFT as well, we find the similar agreement in the CNMG/LCFT correspondence. Furthermore we read the 2-loop correction of graviton and logarithmic mode to HRE from CFT computation. It has distinct feature from the one in pure AdS3 gravity
On AdS/CFT correspondence of EYM fields
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
In the compactized Minkowski space, which is equivalent to the conformal space M4, we introduced a Lorentz metric d σ2 and a Yang-Mills field. Later, we proved that d σ2 and together satisfy the EYM (Einstein-Yang-Mills) equation. In this paper, it is proved that on M4 (which is the boundary of the anti-de-Sitter space AdS5) can be extended to be a Yang-Mills field on AdS5 such that Hua's metric ds2 on AdS5 together with satisfies the EYM equation on AdS5.
Dielectrical and structural characterization of iron oxide added to hydroxyapatite
Indian Academy of Sciences (India)
C C Silva; F P Filho; M F P Graça; M A Valente; A S B Sombra
2008-08-01
In this work we report preparation, structural and dielectric analyses of iron oxide added in hydroxyapatite bioceramic (Ca10(PO4)6(OH)2 – HAP). Hydroxyapatite is the main mineral constituent of teeth and bones with excellent biocompatibility with hard and muscle tissues. The samples were prepared through a calcination procedure associated with dry high-energy ball milling process with different iron concentrations (1, 2.5 and 5 wt%). The dielectric analyses were made measuring the sample impedance in the frequency range 1 kHz–10 MHz, at room temperature. The relative permittivity of the ceramics, at 10 MHz, are between 7.13 ± 0.07 (1 wt%) and 6.20 ± 0.11 (5 wt%) while e″ are between 0.0795 ± 0.008 (1 wt%) and 0.067 ± 0.012 (5 wt%). These characteristics were related to the sample microstructures studied by X-ray diffraction and SEM.
ADS specific accelerator developments: Status in India
International Nuclear Information System (INIS)
Since India envisages the application as thorium–uranium breeder, the ADS must be operated with high beam power to maximize breeding potential. Since the thermalhydraulics issue in spallation target may restrict ~1 GeV proton beam current to ~10 mA on a single target module, an ADS core design is visualized with 3 or more spallation targets that would also help suppress the neutron flux peaking. With this assumption, the R&D objective is to realize a proton accelerator of 30 mA beam current (cw/average) within as short time as feasible. Of the two alternative accelerator types, cyclotron and LINAC, basic indigenous technological know-how, up to limited extent, exists for both
Supporting Dynamic Ad hoc Collaboration Capabilities
International Nuclear Information System (INIS)
Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment
Chu, Chong-Sun
2016-01-01
We propose and study a holographic dual of the type IIB superstring theory of AdS_5 x S^5 in terms of the N=4 superconformal Yang-Mills theory on dS_4. We use the bulk to boundary formalism to evaluate the boundary correlation functions and verify that it agrees with the expected result in dS conformal field theory. The gauge theory is expected to be UV finite and enjoy exact SL(2,Z) strong-weak duality. As the string theory Green-Schwarz sigma model carries an infinite number of classically conserved charges, it also suggest that the superconformal Yang-Mills theory is integrable and deserves further studies.
AD codes of practice 'pressure vessels'
International Nuclear Information System (INIS)
Within the AD-Regelwerk, a manual of regulations, the AD codes of practice HP1 and HP20 have been published for the first time. In contrast to the already existing codes of practice of the series HP, these leaflets do not mainly contain changes in the test details and the course of the procedure, but, in a summarized form, that which has been practiced for years. Comments on the new codes concentrate mainly on those things, which are really new, or which might appear to be new. Furthermore, control lists and proposals for printed forms, addressed to designers and supervisors on the side of the manufacturers, are to contribute to the tests being carried out economically. (orig./RW)
Noncommutative $q$-photon added coherent states
Dey, Sanjib
2016-01-01
We construct the photon added coherent states of a noncommutative harmonic oscillator associated to a $q$-deformed oscillator algebra. Various nonclassical properties of the corresponding system are explored, first, by studying two different types of higher order quadrature squeezing, namely the Hillery-type and the Hong--Mandel-type and, second, by testing the sub-Poissonian nature of photon statistics in higher order with the help of the correlation function and the Mandel parameter. By comparing our results with those of the usual harmonic oscillator, we notice that the quadratures and photon number distributions in noncommutative case are more squeezed for the same values of the parameters and, thus, the photon added coherent states of noncommutative harmonic oscillator may be more nonclassical in comparison to the ordinary harmonic oscillator.
Supporting Dynamic Ad hoc Collaboration Capabilities
Energy Technology Data Exchange (ETDEWEB)
Agarwal, Deborah A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Berket, Karlo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2003-07-14
Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment.
AD/HD: POSSIBLE DIAGNOSIS AND TREATMENT
Directory of Open Access Journals (Sweden)
Karl REICHELT
2008-12-01
Full Text Available The purpose of this paper is to show that a more exact diagnosis and dietary intervention in AD/HD (Attention Deficit/Hyperactivity Disorder is possible and probable. The clinical symptom based diagnosis we suggest may be supplemented with physiological tests. A genetic and environmental inter-action is clearly involved and explainable using phenylketonuria as a model.Method: Examining peer reviewed published papers on gut to blood, blood to brain interaction and effect of interventions in AD/HD and our own studies in the field. The various treatment options are discussed.Results: It can be shown that a gut to brain activity is possible and probable, and dietary intervention is useful and probably safer than drugs. Preliminary data on a small five year follow up of dietary intervention is shown.
Flexible Authentication in Vehicular Ad hoc Networks
Caballero-Gil, P; Molina-Gil, J; Hernández-Goya, C
2010-01-01
A Vehicular Ad-Hoc Network (VANET) is a form of Mobile ad-hoc network, to provide communications among nearby vehicles and between vehicles and nearby fixed roadside equipment. The key operation in VANETs is the broadcast of messages. Consequently, the vehicles need to make sure that the information has been sent by an authentic node in the network. VANETs present unique challenges such as high node mobility, real-time constraints, scalability, gradual deployment and privacy. No existent technique addresses all these requirements. In particular, both inter-vehicle and vehicle-to-roadside wireless communications present different characteristics that should be taken into account when defining node authentication services. That is exactly what is done in this paper, where the features of inter-vehicle and vehicle-to-roadside communications are analyzed to propose differentiated services for node authentication, according to privacy and efficiency needs.
Hubeny, Veronika E
2015-01-01
We give a brief review of the AdS/CFT correspondence, which posits the equivalence between a certain gravitational theory and a lower-dimensional non-gravitational one. This remarkable duality, formulated in 1997, has sparked a vigorous research program which has gained in breadth over the years, with applications to many aspects of theoretical (and even experimental) physics, not least to general relativity and quantum gravity. To put the AdS/CFT correspondence in historical context, we start by reviewing the relevant aspects of string theory (of which no prior knowledge is assumed). We then develop the statement of the correspondence, and explain how the two sides of the duality map into each other. Finally, we discuss the implications and applications of the correspondence, and indicate some of the current trends in this subject. The presentation attempts to convey the main concepts in a simple and self-contained manner, relegating supplementary remarks to footnotes.
AD-1 with research pilot Richard E. Gray
1982-01-01
1981/1982. Richard E. Gray was born March 11, 1945 in Newport News, Virginia; he died on November 8, 1982 at Edwards, California, in a T-37 spin accident. The Ames-Dryden-1 (AD-1) aircraft was designed to investigate the concept of an oblique (pivoting) wing. The wing could be rotated on its center pivot, so that it could be set at its most efficient angle for the speed at which the aircraft was flying. NASA Ames Research Center Aeronautical Engineer Robert T. Jones conceived the idea of an oblique wing. His wind tunnel studies at Ames (Moffett Field, CA) indicated that an oblique wing design on a supersonic transport might achieve twice the fuel economy of an aircraft with conventional wings. The oblique wing on the AD-1 pivoted about the fuselage, remaining perpendicular to it during slow flight and rotating to angles of up to 60 degrees as aircraft speed increased. Analytical and wind tunnel studiesthat Jones conducted at Ames indicated that a transport-sized oblique-wing aircraft flying at speeds of up to Mach 1.4 (1.4 times the speed of sound) would have substantially better aerodynamic performance than aircraft with conventional wings. The AD-1 structure allowed the project to complete all of its technical objectives. The type of low-speed, low-cost vehicle - as expected - exhibited aeroelastic and pitch-roll-coupling effects that contributed to poor handling at sweep angles above 45 degrees. The fiberglass structure limited the wing stiffness that would have improved the handling qualities. Thus, after completion of the AD-1 project, there was still a need for a transonic oblique-wing research aircraft to assess the effects of compressibility, evaluate a more representative structure, and analyze flight performance at transonic speeds (those on either side of the speed of sound). The aircraft was delivered to the Dryden Flight Research Center, Edwards, CA, in March 1979 and its first flight was on December 21, 1979. Piloting the aircraft on that flight, as well
Covariant anomalies and Hawking radiation from Kaluza–Klein AdS black holes
Indian Academy of Sciences (India)
Chuan-Yi Bai
2013-02-01
In this paper, Hawking radiation is studied from four-dimensional (4D) Kaluza–Klein (KK) AdS black holes via the method of anomaly cancellation. The {|bf KK-AdS} black hole considered is a non-extremal charged rotating solution in the theory of 4D gauged supergravity. Its Hawking fluxes of electric charge, angular momentum and energy momentum tensor are derived here. Our results support the common view that Hawking radiation is the quantum effect arising at the event horizon.
Geodesic Motions in AdS Soliton Background Space-time
Shi, Han-qing
2016-01-01
We study both massive and massless particle's geodesic motion in the background of general dimensional AdS-Sol space-time. We find that the massive particles oscillate along the radial direction, while massless particles experience one-time bouncing as they approach the "horizon" line of the soliton. Our results provide a direct way to understand the negative energy/masses leading to the AdS-Sol geometry. As a potential application, we extend the point particle to a 3-brane and fix the background as a 5+1 dimension AdS-Sol, thus obtain a very natural bouncing/cyclic cosmological model.
Effects of dark energy on P-V criticality of charged AdS black holes
Li, Gu-Qiang
2014-01-01
In this Letter, we investigate the effects of dark energy on $P-V$ criticality of charged AdS black holes by considering the case of the RN-AdS black holes surrounded by quintessence. By treating the cosmological constant as thermodynamic pressure, we study its thermodynamics in the extended phase space. It is shown that quintessence dark energy does not affect the existence of small/large black hole phase transition. For the case $\\omega_q=-2/3$ we derive analytic expressions of critical phy...
The Added-Worker Effect: A Reappraisal
Shelly J. Lundberg
1981-01-01
In this paper, the added worker effect is interpreted as a response to uncertain returns to labour supply offers by members of a household. A model of household labour supply is developed In which each member's current labour force status affects the job search and participation decisions of the other and thus the probabilities of observed transitions between the states of employment, unemployment, and non-participation. The determinants of actual household transitions are then investigated u...
ADS specific accelerator developments: Status in China
International Nuclear Information System (INIS)
A basic research programme of ADS was launched in 2000 under the support of the Ministry of Science and Technology, China. In this programme some key technologies are studied for an intense beam proton LINAC, including construction of an ECR proton source and a pulsed beam RFQ accelerator. Further, Chinese Academy of Sciences also gave a support to LINAC research in the field of medium-β superconducting cavity
Enhanced Wireless Network Ad Hoc Pattern
M. Kamalakannan; V. Khanaa
2012-01-01
Early simulation experience with wireless ad hoc networks suggests that their capacity can be surprisingly low, due to the requirement that nodes forward each others’ packets. The achievable capacity depends on network size, traffic patterns and detailed local radio interactions. This study examines these factors alone and in combination, using simulation and analysis from first principles. Our results include both specific constants and general relationship Scaling helpful in understanding t...
The Great Collapse in Value Added Trade
Arne J Nagengast; Stehrer, Robert
2015-01-01
This paper studies the great collapse in value added trade using a structural decomposition analysis. We show that changes in vertical specialisation accounted for almost half of the great trade collapse, while the previous literature on gross trade has mainly focused on final expenditure, inventory adjustment and adverse credit supply conditions. The decline in international production sharing during the crisis may partially account for the observed decrease in global trade elasticities in r...
The great collapse in value added trade
Nagengast, Arne J.; Stehrer, Robert
2015-01-01
This paper studies the great collapse in value added trade using a structural decomposition analysis. We show that changes in vertical specialisation accounted for almost half of the great trade collapse, while the previous literature on gross trade has mainly focused on final expenditure, inventory adjustment and adverse credit supply conditions. The decline in international production sharing during the crisis may partially account for the observed decrease in global trade elasticities in r...
Routing Security in Ad Hoc Wireless Networks
Pervaiz, Mohammad O.; Cardei, Mihaela; Wu, Jie
Wireless networks provide rapid, untethered access to information and computing, eliminating the barriers of distance, time, and location for many applications ranging from collaborative, distributed mobile computing to disaster recovery (such as fire, flood, earthquake), law enforcement (crowd control, search, and rescue), and military communications (command, control, surveillance, and reconnaissance). An ad hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any established infrastructure or centralized administration [11
SILAGE CANE SUGAR ADDED WITH DRIED BREWER
W. J. R. Castro; A. M. Zanine; D.J. Ferreira
2015-01-01
The objective of this experiment was to evaluate the fermentative parameters and chemical composition of silage cane sugar added with residue dried brewery. The experimental design was completely randomized with four treatments and four replications: 100% cane sugar; 90% of cane sugar + 10% residue dried brewer; 80% of cane sugar + 20% residue dried brewer and 70% cane sugar + 30% dried brewer based on natural matter, composed silages. The sugar cane was chopped in a stationary machine with f...
Aeronautical Ad Hoc Network for Civil Aviation
Vey, Quentin; Pirovano, Alain; Radzik, José; Garcia, Fabien
2014-01-01
Aeronautical communication systems are constantly evolving in order to handle the always increasing flow of data generated by civil aviation. In this article we first present communication systems currently used for en-route aircraft. We then propose Aeronautical Ad hoc NETwork (AANET) as a complementary communication system and demonstrate its connectivity and assess the throughput by simulations based on real aircraft trajectories over the French sky and over the Atlantic ocean.
Drag cancellation by added-mass pumping
Giorgio-Serchi, F
2016-01-01
A submerged body subject to a sudden shape-change experiences large forces due to the variation of added-mass energy. While this phenomenon has been studied for single actuation events, application to sustained propulsion requires studying \\textit{periodic} shape-change. We do so in this work by investigating a spring-mass oscillator submerged in quiescent fluid subject to periodic changes in its volume. We develop an analytical model to investigate the relationship between added-mass variation and viscous damping and demonstrate its range of application with fully coupled fluid-solid Navier-Stokes simulations at large Stokes number. Our results demonstrate that the recovery of added-mass kinetic energy can be used to completely cancel the viscous damping of the fluid, driving the onset of sustained oscillations with amplitudes as large as four times the average body radius $r_0$. A quasi-linear relationship is found to link the terminal amplitude of the oscillations $X$, to the extent of size change $a$, wit...
Entangled photon-added coherent states
Domínguez-Serna, Francisco A.; Mendieta-Jimenez, Francisco J.; Rojas, Fernando
2016-08-01
We study the degree of entanglement of arbitrary superpositions of m, n photon-added coherent states (PACS) {|{ψ }rangle } ∝ u {|{{α },m}rangle }{|{{β },n }rangle }+ v {|{{β },n}rangle }{|{{α },m}rangle } using the concurrence and obtain the general conditions for maximal entanglement. We show that photon addition process can be identified as an entanglement enhancer operation for superpositions of coherent states (SCS). Specifically for the known bipartite positive SCS: {|{ψ }rangle } ∝ {|{α }rangle }_a{|{-α }rangle }_b + {|{-α }rangle }_a{|{α }rangle }_b whose entanglement tends to zero for α → 0, can be maximal if al least one photon is added in a subsystem. A full family of maximally entangled PACS is also presented. We also analyzed the decoherence effects in the entangled PACS induced by a simple depolarizing channel . We find that robustness against depolarization is increased by adding photons to the coherent states of the superposition. We obtain the dependence of the critical depolarization p_{ {crit}} for null entanglement as a function of m,n, α and β.
Ad Serving Using a Compact Allocation Plan
Chen, Peiji; Mandalapu, Srinath; Nagarajan, Chandrashekhar; Shanmugasundaram, Jayavel; Vassilvitskii, Sergei; Vee, Erik; Yu, Manfai; Zien, Jason
2012-01-01
A large fraction of online display advertising is sold via guaranteed contracts: a publisher guarantees to the advertiser a certain number of user visits satisfying the targeting predicates of the contract. The publisher is then tasked with solving the ad serving problem - given a user visit, which of the thousands of matching contracts should be displayed, so that by the expiration time every contract has obtained the requisite number of user visits. The challenges of the problem come from (1) the sheer size of the problem being solved, with tens of thousands of contracts and billions of user visits, (2) the unpredictability of user behavior, since these contracts are sold months ahead of time, when only a forecast of user visits is available and (3) the minute amount of resources available online, as an ad server must respond with a matching contract in a fraction of a second. We present a solution to the guaranteed delivery ad serving problem using {\\em compact allocation plans}. These plans, computed offl...
ADS: The Next Generation Search Platform
Accomazzi, A.; Kurtz, M. J.; Henneken, E. A.; Chyla, R.; Luker, J.; Grant, C. S.; Thompson, D. M.; Holachek, A.; Dave, R.; Murray, S. S.
2015-04-01
Four years after the last LISA meeting, the NASA Astrophysics Data System (ADS) finds itself in the middle of major changes to the infrastructure and contents of its database. In this paper we highlight a number of features of great importance to librarians and discuss the additional functionality that we are currently developing. Our citation coverage has doubled since 2010 and now consists of over 10 million citations. We are normalizing the affiliation information in our records and we have started collecting and linking funding sources with papers in our system. At the same time, we are undergoing major technology changes in the ADS platform. We have rolled out and are now enhancing a new high-performance search engine capable of performing full-text as well as metadata searches using an intuitive query language. We are currently able to index acknowledgments, affiliations, citations, and funding sources. While this effort is still ongoing, some of its benefits are already available through the ADS Labs user interface and API at http://adslabs.org/adsabs/.
ADS: The Next Generation Search Platform
Accomazzi, Alberto; Henneken, Edwin A; Chyla, Roman; Luker, James; Grant, Carolyn S; Thompson, Donna M; Holachek, Alexandra; Dave, Rahul; Murray, Stephen S
2015-01-01
Four years after the last LISA meeting, the NASA Astrophysics Data System (ADS) finds itself in the middle of major changes to the infrastructure and contents of its database. In this paper we highlight a number of features of great importance to librarians and discuss the additional functionality that we are currently developing. Starting in 2011, the ADS started to systematically collect, parse and index full-text documents for all the major publications in Physics and Astronomy as well as many smaller Astronomy journals and arXiv e-prints, for a total of over 3.5 million papers. Our citation coverage has doubled since 2010 and now consists of over 70 million citations. We are normalizing the affiliation information in our records and, in collaboration with the CfA library and NASA, we have started collecting and linking funding sources with papers in our system. At the same time, we are undergoing major technology changes in the ADS platform which affect all aspects of the system and its operations. We hav...
Data Confidentiality in Mobile Ad hoc Networks
Directory of Open Access Journals (Sweden)
Hamza Aldabbas
2012-03-01
Full Text Available Mobile ad hoc networks (MANETs are self-configuring infrastructure-less networks comprised of mobile nodes that communicate over wireless links without any central control on a peer-to-peer basis.These individual nodes act as routers to forward both their own data and also their neighbours’ data by sending and receiving packets to and from other nodes in the network. The relatively easy configuration and the quick deployment make ad hoc networks suitable the emergency situations (such as human or natural disasters and for military units in enemy territory. Securing data dissemination between these nodes in such networks, however, is a very challenging task. Exposing such information to anyone else other than the intended nodes could cause a privacy and confidentiality breach, particularly in military scenarios. In this paper we present a novel framework to enhance the privacy and data confidentiality in mobile ad hoc networks by attaching the originator policies to the messages as they are sent between nodes. We evaluate our framework using the Network Simulator (NS-2 to check whether the privacy and confidentiality of the originator are met. For this we implemented the Policy Enforcement Points (PEPs, as NS-2 agents that manage and enforce the policies attached to packets at every node in the MANET.
International Nuclear Information System (INIS)
We consider a geometric zero-radius limit for strings on AdS5xS5, where the anti-de Sitter hyperboloid becomes the projective lightcone. In this limit the fifth dimension becomes nondynamical, yielding a different ''holographic'' interpretation than the usual ''bulk to boundary'' one. When quantized on the random lattice, the fifth coordinate acts as a new kind of Schwinger parameter, producing Feynman rules with normal propagators at the tree level: For example, in the bosonic case ordinary massless φ4 theory is obtained. In the superstring case we obtain new, manifestly cal N = 4 supersymmetric rules for cal N = 4 super Yang-Mills. These gluons are also different from those of the usual AdS/CFT correspondence: They are the ''partons'' that make up the usual ''hadrons'' of the open and closed strings in the familiar QCD string picture. Thus, their coupling gYM and rank N of the ''color'' gauge group are different from those of the ''flavor'' gauge group of the open string. As a result we obtain different perturbation expansions in radius, coupling, and 1/N. (author)
Status of ADS research in Korea
International Nuclear Information System (INIS)
KAERI has been working on ADS since 1997. The KAERI ADS system is called HYPER (HYbrid Power Extraction Reactor). HYPER research started as a 10 year nuclear research program funded by the government. The ADS research of KAERI consists of 3 stages. A basic concept of HYPER was established in the first stage (1997 - 2000) of the development. The basic technology related to HYPER was investigated in the second stage (2001 - 2003) while upgrading the design. The third stage of research started in March, 2004. The conceptual design of HYPER core will be completed in the third stage (2004 - 2006). The investigation of key technologies will be continued in the third stage. The conceptual design of HYPER core was almost finished in the second stage. The upgrade of core design and transient study will be done in the third stage. Regarding experimental research, fuel and Pb-Bi study were performed during the second stage. U surrogate fuel was fabricated and tested. KAERI joined MEGAPIE project in 2001 for Pb-Bi research. KAERI also installed the static Pb-Bi corrosion test device in 2003 and started experiments. KAERI will complete the construction of Pb-Bi corrosion loop in 2004. I-NERI program related to lead-alloy experiment will be launched in 2004. For the fuel/FP target study, KAERI plans to perform fission product irradiation test using KAERI's research reactor HANARO
The electronic structure of Ca-intercalated superconducting graphite CaC6
International Nuclear Information System (INIS)
We have measured Ca-intercalated graphite superconductor CaC6 (Tc 11.2 K) by soft X-ray photoemission spectroscopy in order to understand the electronic structure. For the valence band, we observed several structures that correspond to those of calculated density of states with the partial density of states of Ca 3d at the Fermi level (EF). We also observed core level spectra that are a very large asymmetric Ca 2p and asymmetric C 1s for CaC6, suggesting the existence of conduction electrons derived from Ca 3d and a charge transfer from Ca to graphene layer. These results provide spectroscopic evidence for PDOS of Ca 3d at EF. From a comparison of electronic structure of CaC6 and other graphite intercalation compounds (GICs), we found the difference between CaC6 and other superconducting GICs, which provides deeper understanding of the superconductivity of CaC6.
Seismic and sedimentological evidence of the 518 AD earthquake at Lake Ohrid (Macedonia/Albania)
Wagner, B.; Francke, A.; Sulpizio, R.; Zanchetta, G.; Lindhorst, K.; Krastel, S.; Vogel, H.
2012-12-01
Lake Ohrid shared by the Republics of Albania and Macedonia is formed by a tectonically active graben within the South Balkan and suggested to be the oldest lake in Europe. Several studies have shown that the lake provides a valuable record of climatic and environmental changes and a distal tephrostratigraphic record of volcanic eruptions from Italy. Fault structures identified in seismic data demonstrate that sediments have also the potential to record tectonic activity in the region. Here, we provide an example of linking tephrostratigraphic information and environmental changes with tectonic activity and anthropogenic impact. Historical documents indicate that a major earthquake destroyed the city of Ohrid at 518 AD. This earthquake is documented in multichannel seismic profiles, in parametric sediment echosounder profiles, and in a ca. 10 m long sediment record from the western part of the lake. The sediment record exhibits a ca. 2 m thick mass wasting event, which is chronologically well constrained by the underlying AD 472 / AD 512 tephra and cross correlation with other sediment sequences with similar geochemical characteristics of the Holocene.
International Nuclear Information System (INIS)
Calcium influx drives two opposing voltage-activated calcium channel (CaV) self-modulatory processes: calcium-dependent inactivation (CDI) and calcium-dependent facilitation (CDF). Specific Ca2+/calmodulin (Ca2+/CaM) lobes produce CDI and CDF through interactions with the CaVα1 subunit IQ domain. Curiously, Ca2+/CaM lobe modulation polarity appears inverted between CaV1s and CaV2s. Here, we present crystal structures of CaV2.1, CaV2.2, and CaV2.3 Ca2+/CaM-IQ domain complexes. All display binding orientations opposite to CaV1.2 with a physical reversal of the CaM lobe positions relative to the IQ α-helix. Titration calorimetry reveals lobe competition for a high-affinity site common to CaV1 and CaV2 IQ domains that is occupied by the CDI lobe in the structures. Electrophysiological experiments demonstrate that the N-terminal CaV2 Ca2+/C-lobe anchors affect CDF. Together, the data unveil the remarkable structural plasticity at the heart of CaV feedback modulation and indicate that CaV1 and CaV2 IQ domains bear a dedicated CDF site that exchanges Ca2+/CaM lobe occupants
Recent developments in nuclear data for ADS
International Nuclear Information System (INIS)
Modern particle accelerators offer new opportunities to dramatically reshape the way we think about nuclear energy, and challenge some of the thorniest problems linked to its industrial use, e.g. nuclear waste. A powerful proton accelerator driving a sub-critical fission reactor could be used for producing energy more safely and burning up the extra spent fuel which so far has been stored in geological repositories. Although large R and D efforts are required to successfully implement such Accelerator Driven Systems (ADS), an important theoretical effort is also required to extend the nuclear data libraries, originally developed for existing nuclear reactors needs. The energies and isotopes involved in ADS do not necessarily overlap the range covered by the current nuclear reactors, and therefore there is a strong and urgent need to review and complement the nuclear cross sections databases to efficiently and safely build these ADS. In this workshop, we will review some of the strength and deficiencies in the existing nuclear data libraries, for applications to ADS projects. A major step forward to extend these libraries has been achieved recently by the release of the LA150 cross section library [M.B. Chadwick et al., NSE 131, 293 (1999)], evaluating reactions cross sections for different materials important for ADS, up to 150 MeV incident energies. We will devote a rather large fraction of theses lectures to present the latest developments in LA150. We will also present various numerical simulations performed in order to test and benchmark this new data library. Such evaluations rely on nuclear reaction calculations performed with the GNASH code, and on available experimental data. We will therefore briefly review the physical models used in these calculations and present their importance in the GNASH code. Another part in developing accurate nuclear data library consists in the evaluation of available experimental data, as an attempt to significantly reduce the
A reference concept for ADS accelerators
International Nuclear Information System (INIS)
Accelerator Driven Systems (ADS) for transmutation of nuclear waste require proton accelerators delivering order-of-magnitude proton fluxes of 5-10 mA for demonstrators and 20-50 mA for large industrial systems. The envisaged energy range is 350 MeV - 1 GeV. These characteristics show that such a machine belongs to the category of the so-called HPPA (high-power proton accelerators), with multi-megawatt beam power. HPPA are presently very actively studied (or even under construction) for a rather broad use in fundamental or applied science. Compared to other HPPA, many features and requirements are similar for the ADS driver, however, there is a need for exceptional 'reliability'. Because of the induced thermal stress to the subcritical assembly, the number of unwanted 'beam-trips' should not exceed a few per year, a requirement that is several orders of magnitude above usual performance. Consecutive to the work of the European Technical Working Group (ETWG) on ADS, the Preliminary Design Study of an Experimental ADS (PDS-XADS) was launched in 2001 as a 5th Framework Program EC project. A special working package (WP3) was dedicated to the accelerator design, and in particular taking into account that the issue of 'beam-trips' could be a potential 'show-stopper' for ADS technology in general. A reference solution, based on a linear superconducting accelerator with its associated doubly achromatic beam line has been worked out up to some detail. For high reliability, the proposed design is intrinsically fault tolerant, relying on highly modular 'de-rated' components associated to a fast digital feedback system. The proposed solution also appears to be robust concerning operational aspects like maintenance and radioprotection. A roadmap for construction as well as the required consolidated budget was elaborated. A program for the remaining R and D, focused on experimental reliability demonstration of prototypical components has been elaborated. This R and D will be
Mori, Masayuki X.; Vander Kooi, Craig W.; Leahy, Daniel J.; Yue, David T.
2008-01-01
Calmodulin (CaM) regulation of Ca2+ channels is central to Ca2+ signaling. CaV1 versus CaV2 classes of these channels exhibit divergent forms of regulation, potentially relating to customized CaM/IQ interactions among different channels. Here, we report the crystal structures for the Ca2+/CaM—IQ domains of both CaV2.1 and CaV2.3 channels. These highly similar structures emphasize that major CaM contacts with the IQ domain extend well upstream of traditional consensus residues. Surprisingly, u...
STATISTICAL ENTROPIES OF THE TAUB-NUT/BOLT AdS SPACES FROM THE HORIZON CONFORMAL FIELD THEORY
Institute of Scientific and Technical Information of China (English)
JING JI-LIANG; ZHOU SAN-QING; HUANG YI-BIN
2001-01-01
The covariant phase technique is used to compute the constraint algebra of the four-dimensional space-times which are asymptotic to anti-de Sitter (AdS), such as the planar Taub-NUT AdS and Taub-bolt AdS spaces, and the hyperbolic Taub-bolt AdS space. The standard Virasoro subalgebrae with corresponding central charges for these objects are constructed and the resulting densities of states yield the expected Bekenstein-Hawking entropies.
Tachyon inflation in an AdS braneworld with back-reaction
Bilic, Neven; Djordjevic, Goran; Milosevic, Milan
2016-01-01
We analyze the inflationary scenario based on the tachyon field coupled with the radion of the second Randall-Sundrum model (RSII). The tachyon Lagrangian is derived from the dynamics of a 3-brane moving in the five dimensional bulk. The AdS$_5$ geometry of the bulk is extended to include the radion. Using the Hamiltonian formalism we find four nonlinear field equations supplemented by the modified Friedmann equations of the RSII braneworld cosmology. After a suitable rescaling we reduce the parameters of our model to only one free parameter related to the brane tension and the AdS$_5$ curvature. We solve the equations numerically assuming a reasonably wide range of initial conditions determined by physical considerations. Varying the free parameter and initial conditions we confront our results with the Planck 2015 data.
Massive quiver matrix models for massive charged particles in AdS
Asplund, Curtis T; Dzienkowski, Eric
2016-01-01
We present a new class of ${\\cal N}=4$ supersymmetric quiver matrix models and argue that it describes the stringy low-energy dynamics of internally wrapped D-branes in four-dimensional anti-de Sitter (AdS) flux compactifications. The Lagrangians of these models differ from previously studied quiver matrix models by the presence of mass terms, associated with the AdS gravitational potential, as well as additional terms dictated by supersymmetry. These give rise to dynamical phenomena typically associated with the presence of fluxes, such as fuzzy membranes, internal cyclotron motion and the appearance of confining strings. We also show how these models can be obtained by dimensional reduction of four-dimensional supersymmetric quiver gauge theories on a three-sphere.
Coordinate dependence of Chern-Simons theory on noncommutative AdS3
International Nuclear Information System (INIS)
We investigate the coordinate dependence of noncommutative theory by studying the solutions of noncommutative U(1, 1) x U(1, 1) Chern-Simons theory on AdS3 in polar and rectangular coordinates. We assume that only the space coordinates are noncommuting. When the two coordinate systems are equivalent only up to first order in the noncommutativity parameter θ, we investigate the effect of this non-exact equivalence between the two coordinate systems for two cases, a conical solution and a BTZ black hole solution in noncommutative AdS3, by using the Seiberg-Witten map. In each case, the noncommutative solutions in the two coordinate systems obtained from the same corresponding commutative solution turn out to be different even to the first order in θ.
Vector condensate and AdS soliton instability induced by a magnetic field
International Nuclear Information System (INIS)
We continue to study the holographic p-wave superconductor model in the Einstein-Maxwell-complex vector field theory with a non-minimal coupling between the complex vector field and the Maxwell field. In this paper we work in the AdS soliton background which describes a conformal field theory in the confined phase and focus on the probe approximation. We find that an applied magnetic field can lead to the condensate of the vector field and the AdS soliton instability. As a result, a vortex lattice structure forms in the spatial directions perpendicular to the applied magnetic field. As a comparison, we also discuss the vector condensate in the Einstein-SU(2) Yang-Mills theory and find that in the setup of the present paper, the Einstein-Maxwell-complex vector field model is a generalization of the SU(2) model in the sense that the vector field has a general mass and gyromagnetic ratio
Isometry Group Orbit Quantization of Spinning Strings in AdS_3 x S^3
Heinze, Martin; Megrelidze, Luka
2014-01-01
Describing the bosonic AdS_3 x S^3 particle and string in SU(1,1) x SU(2) group variables, we provide a Hamiltonian treatment of the isometry group orbits of solutions via analysis of the pre-symplectic form. For the particle we obtain a one-parameter family of orbits parameterized by creation-annihilation variables, which leads to the Holstein-Primakoff realization of the isometry group generators. The scheme is then applied to spinning string solutions characterized by one winding number in AdS_3 and two winding numbers in S^3. We find a two-parameter family of orbits, where quantization again provides the Holstein-Primakoff realization of the symmetry generators with an oscillator type energy spectrum. Analyzing the minimal energy at strong coupling we verify the spectrum of short strings at special values of winding numbers.
Isometry group orbit quantization of spinning strings in AdS3 × S3
Heinze, Martin; Jorjadze, George; Megrelidze, Luka
2015-03-01
Describing the bosonic AdS3 × S3 particle and string in SU(1,1) × SU(2) group variables, we provide a Hamiltonian treatment of the isometry group orbits of solutions via analysis of the pre-symplectic form. For the particle we obtain a one-parameter family of orbits parameterized by creation-annihilation variables, which leads to the Holstein-Primakoff realization of the isometry group generators. The scheme is then applied to spinning string solutions characterized by one winding number in AdS3 and two winding numbers in S3. We find a two-parameter family of orbits, where quantization again provides the Holstein-Primakoff realization of the symmetry generators with an oscillator-type energy spectrum. Analyzing the minimal energy at strong coupling, we verify the spectrum of short strings at special values of winding numbers.
D-instanton in AdS sub 5 and instanton in SYM sub 4
Chu, C S; Wu, Y Y
1999-01-01
Following the observation of Banks and Green that the D-instantons in AdS sub 5 correspond to the instantons in four-dimensional supersymmetric Yang-Mills theory, we study in more detail this correspondence for individual instantons. The supergravity solution for a D-instanton in AdS sub 5 is found using the ansatz used previously for D-instantons in flat space. We check that the actions and supersymmetries match between the D-instanton solution and the Yang-Mills instanton. Generalizing this result, we propose that any supergravity solution satisfying the ansatz corresponds to a (anti-) self-dual Yang-Mills configuration. Using this ansatz a family of identities for correlation functions in the supersymmetric Yang-Mills theory are derived.
Dualities in D=5, N=2 supergravity, black hole entropy, and AdS central charges
International Nuclear Information System (INIS)
The issue of microstate counting for general black holes in D=5, N=2 supergravity coupled to vector multiplets is discussed from various viewpoints. The statistical entropy is computed for the near-extremal case by using the central charge appearing in the asymptotic symmetry algebra of AdS2. Furthermore, we show that the considered supergravity theory enjoys a duality invariance which connects electrically charged black holes and magnetically charged black strings. The near-horizon geometry of the latter turns out to be AdS3 x S2, which allows a microscopic calculation of their entropy using the Brown-Hennaux central charges in Cardy's formula. In both approaches we find perfect agreement between statistical and thermodynamical entropy. (orig.)
Higher-dimensional AdS waves and pp waves with conformally related sources
International Nuclear Information System (INIS)
AdS waves and pp-waves can only be supported by pure radiation fields, for which the only nonvanishing component of the energy-momentum tensor is the energy density along the retarded time. We show that the nonminimal coupling of self-gravitating scalar fields to the higher-dimensional versions of these exact gravitational waves can be done consistently. In both cases, the resulting pure radiation constraints completely fix the scalar field dependence and the form of the allowed self-interactions. More significantly, we establish that the two sets of pure radiation constraints are conformally related for any nonminimal coupling, in spite of the fact that the involved gravitational fields are not necessarily related. In this correspondence, the potential supporting the AdS waves emerges from the self-interaction associated to the pp-waves and a self-dual condition naturally satisfied by the pp-wave scalar fields
Supersymmetric Branes in AdS_2 x S^2 x CY_3
Simons, A; Thompson, D; Yin, X; Simons, Aaron; Strominger, Andrew; Thompson, David; Yin, Xi
2004-01-01
The problem of finding supersymmetric brane configurations in the near-horizon attractor geometry of a Calabi-Yau black hole with magnetic-electric charges (p^I,q_I) is considered. Half-BPS configurations, which are static for some choice of global AdS2 coordinate, are found for wrapped brane configurations with essentially any four-dimensional charges (u^I,v_I). Half-BPS multibrane configurations can also be found for any collection of wrapped branes provided they all have the same sign for the symplectic inner product p^Iv_I-u^Iq_I of their charges with the black hole charges. This contrasts with the Minkowski problem for which a mutually preserved supersymmetry requires alignment of all the charge vectors. The radial position of the branes in global AdS2 is determined by the phase of their central charge.
Unparticles as the Holographic Dual of Gapped AdS Gravity
Domokos, Sophia K
2015-01-01
Naively applying holographic duality to gapped gravity on Anti de Sitter (AdS) space seems to suggest that the stress tensor of the field theory dual cannot be conserved. On the other hand, by symmetry arguments, it seems that the dual should not violate Poincare symmetry. To clarify this apparent contradiction, we study a holographic dual of massive gravity where both the physical background metric and the fiducial metric are AdS. Using the anomalous scaling of the energy momentum tensor as our guide, we conclude that the dual theory is nonlocal. We find that the dual is similar to conformal invariant "unparticle" theories. We show that such theories can be viewed as dimensional reductions of flat-space field theories with inhomogeneous scaling properties.
Renormalization, averaging, conservation laws and AdS (in)stability
Craps, Ben; Evnin, Oleg; Vanhoof, Joris
2015-01-01
We continue our analytic investigations of non-linear spherically symmetric perturbations around the anti-de Sitter background in gravity-scalar field systems, and focus on conservation laws restricting the (perturbatively) slow drift of energy between the different normal modes due to non-linearities. We discover two conservation laws in addition to the energy conservation previously discussed in relation to AdS instability. A similar set of three conservation laws was previously noted for a self-interacting scalar field in a non-dynamical AdS background, and we highlight the similarities of this system to the fully dynamical case of gravitational instability. The nature of these conservation laws is best understood through an appeal to averaging methods which allow one to derive an effective Lagrangian or Hamiltonian description of the slow energy transfer between the normal modes. The conservation laws in question then follow from explicit symmetries of this averaged effective theory.
Conformal mass in Einstein-Gauss-Bonnet AdS gravity
Jatkar, Dileep P; Miskovic, Olivera; Olea, Rodrigo
2015-01-01
In this paper, we show that the physical information given by conserved charges for asymptotically AdS spacetimes in Einstein-Gauss-Bonnet AdS gravity is encoded in the electric part of the Weyl tensor. This result generalizes the conformal mass definition by Ashtekar-Magnon-Das (AMD) to a gravity theory with a Gauss-Bonnet term. This proof makes use of the Noether charges obtained from an action renormalized by the addition of counterterms which depend on the extrinsic curvature (Kounterterms). If the asymptotic fall-off behaviour of the Weyl tensor is same as the one considered in the AMD method, then the Kounterterm charges and the AMD charges agree in any dimension.
Kaluza-Klein supergravity on AdS 3 x S 3
International Nuclear Information System (INIS)
We construct a Chern-Simons type gauged N = 8 supergravity in three spacetime dimensions with gauge group SO4 x T ∞ over the infinite dimensional coset space SO{8, ∞}/(SO8 x SO∞), where T ∞ is an infinite dimensional translation subgroup of SO{8, ∞}. This theory describes the effective interactions of the (infinitely many) supermultiplets contained in the two spin-1 Kaluza-Klein towers arising in the compactification of N (2,0) supergravity in six dimensions on AdS 3 x S 3 with the massless supergravity multiplet. After the elimination of the gauge fields associated with T∞, one is left with an Yang Mills type gauged supergravity with gauge group SO(4), and in the vacuum the symmetry is broken to the (super-)isometry group of AdS 3 x S 3 , with infinitely many fields acquiring masses by a variant of the Brout-Englert-Higgs effect. (author)
CFT dual of charged AdS black hole in the large dimension limit
Guo, Er-Dong; Sun, Jia-Rui
2015-01-01
We study the dual CFT description of the $d+1$-dimensional Reissner-Nordstr\\"om-Anti de Sitter (RN-AdS$_{d+1}$) black hole in the large dimension (large $d$) limit, both for the extremal and nonextremal cases. The central charge of the dual CFT$_2$ (or chiral CFT$_1$) is calculated for the near horizon near extremal geometry which possess an AdS$_2$ structure. Besides, the $Q$-picture hidden conformal symmetry in the nonextremal background can be naturally obtained by a probe charged scalar field in the large $d$ limit, without the need to input the usual limits to probe the hidden conformal symmetry. Furthermore, an new dual CFT description of the nonextremal RN-AdS$_{d+1}$ black hole is found in the large $d$ limit and the duality is analyzed by comparing the entropies, the absorption cross sections and the retarded Green's functions obtained both from the gravity and the dual CFT sides.
Witten diagrams revisited: the AdS geometry of conformal blocks
Hijano, Eliot; Kraus, Per; Perlmutter, Eric; Snively, River
2016-01-01
We develop a new method for decomposing Witten diagrams into conformal blocks. The steps involved are elementary, requiring no explicit integration, and operate directly in position space. Central to this construction is an appealingly simple answer to the question: what object in AdS computes a conformal block? The answer is a "geodesic Witten diagram", which is essentially an ordinary exchange Witten diagram, except that the cubic vertices are not integrated over all of AdS, but only over bulk geodesics connecting the boundary operators. In particular, we consider the case of four-point functions of scalar operators, and show how to easily reproduce existing results for the relevant conformal blocks in arbitrary dimension.
Witten Diagrams Revisited: The AdS Geometry of Conformal Blocks
Hijano, Eliot; Perlmutter, Eric; Snively, River
2015-01-01
We develop a new method for decomposing Witten diagrams into conformal blocks. The steps involved are elementary, requiring no explicit integration, and operate directly in position space. Central to this construction is an appealingly simple answer to the question: what object in AdS computes a conformal block? The answer is a "geodesic Witten diagram," which is essentially an ordinary exchange Witten diagram, except that the cubic vertices are not integrated over all of AdS, but only over bulk geodesics connecting the boundary operators. In particular, we consider the case of four-point functions of scalar operators, and show how to easily reproduce existing results for the relevant conformal blocks in arbitrary dimension.
Weak Field Collapse in AdS: Introducing a Charge Density
Caceres, Elena; Pedraza, Juan F; Yang, Di-Lun
2014-01-01
We study the effect of a non-vanishing chemical potential on the thermalization time of a strongly coupled large Nc gauge theory in (2+1)-dimensions, using a specific bottom-up gravity model in asymptotically AdS space. We first construct a perturbative solution to the gravity-equations, which dynamically interpolates between two AdS black hole backgrounds with different temperatures and chemical potentials, in a perturbative expansion of a bulk neutral scalar field. In the dual field theory, this corresponds to a quench dynamics by a marginal operator, where the corresponding coupling serves as the small parameter in which the perturbation is carried out. The evolution of non-local observables, such as the entanglement entropy, suggests that thermalization time decreases with increasing chemical potential. We also comment on the validity of our perturbative analysis.