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Sample records for hybrid black helleri

  1. The effects of hybridization on divergent venom phenotypes: Characterization of venom from Crotalus scutulatus scutulatus × Crotalus oreganus helleri hybrids.

    Science.gov (United States)

    Smith, Cara Francesca; Mackessy, Stephen P

    2016-09-15

    Hybridization between divergent species can be analyzed to elucidate expression patterns of distinct parental characteristics, as well as to provide information about the extent of reproductive isolation between species. A known hybrid cross between two rattlesnakes with highly divergent venom phenotypes provided the opportunity to examine occurrence of parental venom characteristics in the F1 hybrids as well as ontogenetic shifts in the expression of these characters as the hybrids aged. Although venom phenotypes of adult rattlesnake venoms are known for many species, the effect of hybridization on phenotype inheritance is not well understood, and effects of hybridization on venom ontogeny have not yet been investigated. The current study investigates both phenomena resulting from the hybridization of a male snake with type I degradative venom, Crotalus oreganus helleri (Southern Pacific Rattlesnake), and a female snake with type II highly toxic venom, Crotalus scutulatus scutulatus (Mojave Rattlesnake). SDS-PAGE, enzymology, Western blot and reversed phase HPLC (RP-HPLC) were used to characterize the venom of the C. o. helleri male, the C. s. scutulatus female and their two hybrid offspring as they aged. In general, Crotalus o. helleri × C. s. scutulatus hybrid venoms appeared to exhibit overlapping parental venom profiles, and several different enzyme activity patterns. Both hybrids expressed C. o. helleri father-specific myotoxins as well as C. s. scutulatus mother-specific Mojave toxin. Snake venom metalloprotease activity displayed apparent sex-influenced expression patterns, while hybrid serine protease activities were intermediate to parental activities. The C. s. scutulatus × C. o. helleri hybrid male's venom profile provided the strongest evidence that type I and type II venom characteristics are expressed simultaneously in hybrid venoms, as this snake contained distinctive characteristics of both parental species. However, the possibility of

  2. The effects of Lactobacillus acidophilus as feed supplement on skin mucosal immune parameters, intestinal microbiota, stress resistance and growth performance of black swordtail (Xiphophorus helleri).

    Science.gov (United States)

    Hoseinifar, Seyed Hossein; Roosta, Zahra; Hajimoradloo, Abdolmajid; Vakili, Farzaneh

    2015-02-01

    The present study evaluates the effects of different levels of dietary Lactobacillus acidophilus as feed supplement on intestinal microbiota, skin mucus immune parameters and salinity stress resistance as well as growth performance of black swordtail (Xiphophorus helleri). One-thousand and eight hundred healthy black swordtail larvae (0.03 ± 0.001 g) were randomly distributed in 12 tanks (100 L) at a density of 150 fish per aquaria and fed different levels of dietary L. acidophilus (0, 1.5 × 10(8), 3 × 10(8) and 6 × 10(8) CFU g(-1)) for 10 weeks. At the end of trial, there were significant differences among antibacterial activity of skin mucus in probiotic fed fish and control group (P acidophilus fed fish (P acidophilus significantly elevated black swordtail resistance against salinity stress (i.e survival %) (P acidophilus improved weight gain, SGR, FCR compared to fish fed unsupplemented diet (P acidophilus on mucosal immune parameters, intestinal microbiota, stress resistance and growth parameters of black swordtail and the appropriate inclusion is 6 × 10(8) CFU g(-1).

  3. Hybrid Black-Hole Binary Initial Data

    Science.gov (United States)

    Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-01-01

    "Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

  4. Hybrid black-hole binary initial data

    CERN Document Server

    Mundim, Bruno C; Zlochower, Yosef; Nakano, Hiroyuki; Campanelli, Manuela

    2010-01-01

    Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class.Quant.Grav.27:114005,2010], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculation was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.

  5. Hybrid black-hole binary initial data

    Energy Technology Data Exchange (ETDEWEB)

    Mundim, Bruno C; Zlochower, Yosef; Nakano, Hiroyuki; Campanelli, Manuela [Center for Computational Relativity and Gravitation, School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY14623 (United States); Kelly, Bernard J, E-mail: bcmsma@astro.rit.edu, E-mail: bernard.j.kelly@nasa.gov, E-mail: yosef@astro.rit.edu, E-mail: nakano@astro.rit.edu, E-mail: manuela@astro.rit.edu [CRESST and Gravitational Astrophysics Laboratory, NASA/GSFC, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2011-07-07

    Traditional black-hole (BH) binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al (2010, Class. Quantum Grav. 27 114005), a new binary BH initial data with radiation content derived from post-Newtonian (PN) theory was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless 'wavy' metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesirable features: unphysical horizon mass loss and large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.

  6. Reliable passivation of black phosphorus by thin hybrid coating

    Science.gov (United States)

    Gamage, S.; Fali, A.; Aghamiri, N.; Yang, L.; Ye, P. D.; Abate, Y.

    2017-06-01

    Black phosphorus (BP) possesses several extraordinary physical properties, which include in-plane anisotropy, thickness dependent direct bandgap and high carrier mobility. These physical properties make BP highly desirable from the point of view of fundamental science and modern optoelectronics applications. The excitement about this material has always been accompanied by unreserved skepticism due to its extraordinary degradation under ambient conditions. Here we show ambient degradation of exfoliated BP can be effectively suppressed using thin layer of hybrid metal organic chemical vapor deposition coating of boron nitride (BN) followed by atomic layer deposition coating of Al2O3. We have extensively studied the time dependent surface, optical and electrical properties of BP encapsulated by BN and/or Al2O3 using nanoscale infrared imaging and I-V characterizations. Our results show hybrid thin layer (˜5 nm) BN/Al2O3 coated BP exfoliated on SiO2 substrate is protected from degradation in ambient for over 6 months, much longer than those coated only by BN or Al2O3 layers. Our theoretical modeling of the experimental degradation growth pattern shows that the influence of neighboring elements on the degradation of a given element is minimal for BP flakes with hybrid coating. Electrical characterization further confirms the effectiveness of BN/Al2O3 as encapsulation layer and gate dielectrics with minor changes after several weeks.

  7. Spectra of hybrid synchrotron emission in hot black hole winds

    Science.gov (United States)

    Hayakawa, Ken; Fukue, Jun

    2015-12-01

    We solve radiative transfer to obtain the hybrid synchrotron spectra from a hot, optically thin black hole wind, by integrating the radiative transfer equation in the comoving frame and considering the relativistic effect of wind flow as well as the emission and absorption along the line-of-sight. We find two primary characteristics in the hybrid model: (1) a shoulder at low frequencies and (2) a power-law tail at high frequencies. Even if only 10-4 of the total electron energy is injected as non-thermal electrons, higher luminosity can be produced compared to the pure thermal model. Thus, there is a large difference between the pure thermal model and the hybrid one. In addition, as the wind velocity becomes large, the thermal peak of the comoving spectra shifts toward the high-frequency regime, due to the relativistic Doppler effect. As the wind velocity increases, on the other hand, the thermal peak of the observed spectra shifts toward the low-frequency regime, due to the redshifted part in the far side and limb side.

  8. Aboveground dendromass allometry of hybrid black poplars for energy crops

    Directory of Open Access Journals (Sweden)

    Tatiana Stankova

    2016-06-01

    Full Text Available Cultivation of energy crops is concerned with estimation of the total lignified biomass (dendromass production, which is based on the plantation density and individual plant dendromass. The main objective of this study was to investigate the allometry of aboveground leafless biomass of juvenile black poplar hybrids (Populus deltoides x P. nigra , traditionally used for timber and cellulose production, and to derive generic allometric models for dendromass prediction, relevant to energy crop cultivation in Bulgaria. The study material comprised a variety of growth sites, tree ages and clones, specific to poplar plantings in Bulgaria. We used three principal quantitative predictors: diameter at breast height, total tree height and mean stand (stock height. The models were not differentiated by clone, because the black poplar hybrids tested were not equally represented in the data, and the inclusion of tree age as a predictor variable seemed unreliable, because of the significant, up to 3 years, variation, which was possible within the narrow age range investigated. We defined the mean stand (stock height as a composite quantitative variable, which reflected the interaction between the time since planting (age, site quality and the intrinsic growth potential. Stepwise and backward multiple regression analyses were applied to these quantitative variables and their products and sets of adequacy and goodnessof-fit criteria were used to derive individual biomass models for stem and branches. Then we developed compatible additive systems of models for stem, branch and total lignified biomass in log-transformed form. Finally, the prediction data were back-transformed, applying correction for bias, and were cross-validated. Three systems of generic equations were derived to enable flexible model implementation. Equation system M1 proposes a stem biomass model based on tree and stand heights and stem diameter, and a model for

  9. Aboveground dendromass allometry of hybrid black poplars for energy crops

    Directory of Open Access Journals (Sweden)

    Tatiana Stankova

    2016-06-01

    Full Text Available Cultivation of energy crops is concerned with estimation of the total lignified biomass (dendromass production, which is based on the plantation density and individual plant dendromass. The main objective of this study was to investigate the allometry of aboveground leafless biomass of juvenile black poplar hybrids (Populus deltoides x P. nigra , traditionally used for timber and cellulose production, and to derive generic allometric models for dendromass prediction, relevant to energy crop cultivation in Bulgaria. The study material comprised a variety of growth sites, tree ages and clones, specific to poplar plantings in Bulgaria. We used three principal quantitative predictors: diameter at breast height, total tree height and mean stand (stock height. The models were not differentiated by clone, because the black poplar hybrids tested were not equally represented in the data, and the inclusion of tree age as a predictor variable seemed unreliable, because of the significant, up to 3 years, variation, which was possible within the narrow age range investigated. We defined the mean stand (stock height as a composite quantitative variable, which reflected the interaction between the time since planting (age, site quality and the intrinsic growth potential. Stepwise and backward multiple regression analyses were applied to these quantitative variables and their products and sets of adequacy and goodnessof-fit criteria were used to derive individual biomass models for stem and branches. Then we developed compatible additive systems of models for stem, branch and total lignified biomass in log-transformed form. Finally, the prediction data were back-transformed, applying correction for bias, and were cross-validated. Three systems of generic equations were derived to enable flexible model implementation. Equation system M1 proposes a stem biomass model based on tree and stand heights and stem diameter, and a model for

  10. Venom variation in hemostasis of the southern Pacific rattlesnake (Crotalus oreganus helleri): isolation of hellerase.

    Science.gov (United States)

    Salazar, Ana Maria; Guerrero, Belsy; Cantu, Bruno; Cantu, Esteban; Rodríguez-Acosta, Alexis; Pérez, John C; Galán, Jacob A; Tao, Andy; Sánchez, Elda E

    2009-04-01

    Envenomations by the southern Pacific rattlesnake (Crotalus oreganus helleri) are the most common snakebite accidents in southern California. Intraspecies venom variation may lead to unresponsiveness to antivenom therapy. Even in a known species, venom toxins are recognized as diverse in conformity with interpopulational, seasonal, ontogenetic and individual factors. Five venoms of individual C. oreganus helleri located in Riverside and San Bernardino counties of southern California were studied for their variation in their hemostatic activity. The results demonstrated that Riverside 2 and San Bernardino 1 venoms presented the highest lethal activity without hemorrhagic activity. In contrast, San Bernardino 2 and 3 venoms had the highest hemorrhagic and fibrinolytic activities with low lethal and coagulant activities. Riverside 1, Riverside 2 and San Bernardino 1 venoms presented a significant thrombin-like activity. San Bernardino 2 and 3 venoms presented an insignificant thrombin-like activity. In relation to the fibrinolytic activity, San Bernardino 3 venom was the most active on fibrin plates, which was in turn neutralized by metal chelating inhibitors. These results demonstrate the differences amongst C. oreganus helleri venoms from close localities. A metalloproteinase, hellerase, was purified by anionic and cationic exchange chromatographies from San Bernardino 3 venom. Hellerase exhibited the ability to break fibrin clots in vitro, which can be of biomedically importance in the treatment of heart attacks and strokes.

  11. Catalytic Enhancement of Carbon Black and Coal-Fueled Hybrid Direct Carbon Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    Hybrid direct carbon fuel cells (HDCFCs) consisting of a solid carbon (carbon black)-molten carbonate ((62–38 wt% Li-K)2CO3) mixtures in the anode chamber of an anode-supported solid oxide fuel cell type full-cell are tested for their electrochemical performance between 700 and 800°C. Performance...

  12. Influence of nanoclay-carbon black hybrid fillers on cure and properties of natural rubber compounds

    NARCIS (Netherlands)

    Sapkota, J.; Poikelispää, M.; Das, A.; Dierkes, W.K.; Vuorinen, J.

    2013-01-01

    The influence of organically modified nanoclay-carbon black (CB) hybrid filler on the curing behavior of natural rubber (NR) was explored in this investigation. Here an effort was paid to understand the curing kinetics of organomodified nanoclay filled rubber compounds. On the basis of two different

  13. Photonic devices based on black phosphorus and related hybrid materials

    Science.gov (United States)

    Vitiello, M. S.; Viti, L.

    2016-08-01

    Artificial semiconductor heterostructures played a pivotal role in modern electronic and photonic technologies, providing a highly effective means for the manipulation and control of carriers, from the visible to the far-infrared, leading to the development of highly efficient devices like sources, detectors and modulators. The discovery of graphene and the related fascinating capabilities have triggered an unprecedented interest in devices based on inorganic two-dimensional (2D) materials. Amongst them, black phosphorus (BP) recently showed an extraordinary potential in a variety of applications across micro-electronics and photonics. With an energy gap between the gapless graphene and the larger gap transition metal dichalcogenides, BP can form the basis for a new generation of high-performance photonic devices that could be specifically engineered to comply with different applications, like transparent saturable absorbers, fast photocounductive switches and low noise photodetectors, exploiting its peculiar electrical, thermal and optical anisotropy. This paper will review the latest achievements in black-phosphorus-based THz photonics and discuss future perspectives of this rapidly developing research field.

  14. Selecting black-spot resistant papaya genotypes derived from backcrossing and hybrids.

    Science.gov (United States)

    Poltronieri, T P S; Silveira, S F; Vivas, M; Santa Catarina, R; Cortes, D F M; Azevedo, A O N; Pereira, M G

    2017-02-23

    Papaya crop is important to Brazilian agribusiness. However, the expansion of papaya cultivation in the country is affected by the absence of commercial cultivars presenting good disease resistance. The black-spot caused by the fungus Asperisporium caricae is the most damaging foliar disease affecting Brazilian papaya crops. The use of genetically resistant cultivars is a promising strategy to reduce the dependence of papaya crops on fungicides. A field split-plot experiment was carried out in the municipality of Linhares, Espírito Santo State, and included 20 hybrids derived from the cross between 14 superior lines and four elite genotypes ('SS72/12', 'SEKATI', 'JS/12' and '41/7'), two commercial cultivars ('Golden' and 'Tainung 01'), and the superior line '36/7', which were evaluated for resistance to black-spot in the fruits and leaves. The treatments were arranged in a randomized block design with six repetitions of three plants per plot. The incidence and severity of black spot in the fruits and leaves were evaluated at three different times in the 2015-2016 crop season. Lines 4, 9, 21, and the parent SEKATI were notable for their capacity to reduce disease severity in the leaves and fruits. Lines 1, 2, 9, 16, and 19, and the parents 'SEKATI' and 'SS-72/12' had reduced disease incidence in their fruits. The most resistant hybrids 'SS-72/12 X 4', 'SS-72/12 X 6', 'SEKATI X 1', 'SEKATI X 2', 'SEKATI X 6', 'SEKATI X 9', and 'SEKATI X 20' presented negative heterosis values for improved black-spot resistance. The current study allowed the selection of black-spot resistant genotypes and hybrids, which presented a significantly reduced disease index in the field.

  15. Systematics of the Platyrrhinus helleri species complex (Chiroptera: Phyllostomidae), with descriptions of two new species

    Science.gov (United States)

    Velazco, Paúl M.; Gardner, Alfred L.; Patterson, Bruce D.

    2010-01-01

    Platyrrhinus is a diverse genus of small to large phyllostomid bats characterized by a comparatively narrow uropatagium thickly fringed with hair, a white dorsal stripe, comparatively large inner upper incisors that are convergent at the tips, and three upper and three lower molars. Eighteen species are currently recognized, the majority occurring in the Andes. Molecular, morphological, and morphometric analyses of specimens formerly identified as Platyrrhinus helleri support recognition of Platyrrhinus incarum as a separate species and reveal the presence of two species from western and northern South America that we describe herein as new (Platyrrhinus angustirostris sp. nov. from eastern Colombia and Ecuador, north-eastern Peru, and Venezuela and Platyrrhinus fusciventris sp. nov. from Guyana, Suriname, French Guiana, Trinidad and Tobago, northern Brazil, eastern Ecuador, and southern Venezuela). These two new species are sister taxa and, in turn, sister to Platyrrhinus incarum.

  16. Acute toxicity of trichlorofon on four viviparous fish: Poecilia latipinna, Poecilia reticulata, Gambusia holbrooki and Xiphophorus helleri (Cyprinodontiformes: Poecilidae

    Directory of Open Access Journals (Sweden)

    Mohammad Forouhar Vajargah

    2014-07-01

    Full Text Available Objective: To determine toxicity and safety margins of trichlorofon in different species as trichlorofon toxicity has a large variation in the susceptibility of different species. Methods: In this research, four viviparous aquarium fish were exposed to trichlorofon for 96 h. LC50 of 24 h, 48 h, 72 h and 96 h were attained by probit analysis software SPSS Version 16. Fish samples were exposed to different concentrations of trichlorofon (5, 10, 20 and 40 mg/L for 96 h and mortality were recorded, separately. Results: The 96 h LC50 of Poecilia latipinna, Poecilia reticulata, Gambusia holbrooki and Xiphophorus helleri were 9.80, 9.80, 9.95 and 7.99 mg/L, respectively. Conclusions: According to the results of this research, LC50 values indicated Xiphophorus helleri was the most resistant and Gambusia holbrooki, with a few differences, was the most sensitive species compared with the fishes examined.

  17. Massive primordial black holes from hybrid inflation as dark matter and the seeds of galaxies

    Science.gov (United States)

    Clesse, Sébastien; García-Bellido, Juan

    2015-07-01

    In this paper we present a new scenario where massive primordial black holes (PBHs) are produced from the collapse of large curvature perturbations generated during a mild-waterfall phase of hybrid inflation. We determine the values of the inflaton potential parameters leading to a PBH mass spectrum peaking on planetarylike masses at matter-radiation equality and producing abundances comparable to those of dark matter today, while the matter power spectrum on scales probed by cosmic microwave background (CMB) anisotropies agrees with Planck data. These PBHs could have acquired large stellar masses today, via merging, and the model passes both the constraints from CMB distortions and microlensing. This scenario is supported by Chandra observations of numerous BH candidates in the central region of Andromeda. Moreover, the tail of the PBH mass distribution could be responsible for the seeds of supermassive black holes at the center of galaxies, as well as for ultraluminous x-ray sources. We find that our effective hybrid potential can originate e.g. from D-term inflation with a Fayet-Iliopoulos term of the order of the Planck scale but sub-Planckian values of the inflaton field. Finally, we discuss the implications of quantum diffusion at the instability point of the potential, able to generate a Swiss-cheese-like structure of the Universe, eventually leading to apparent accelerated cosmic expansion.

  18. Sperm swimming velocity predicts competitive fertilization success in the green swordtail Xiphophorus helleri.

    Directory of Open Access Journals (Sweden)

    Clelia Gasparini

    Full Text Available Sperm competition is expected to favour the evolution of traits that influence the performance of sperm when they compete to fertilize a female's eggs. While there is considerable evidence that selection favours increases in sperm numbers, much less is known about how sperm quality contributes towards competitive fertilization success. Here, we determine whether variation in sperm quality influences competitive fertilization success in the green swordtail Xiphophorus helleri, a highly promiscuous livebearing fish. We use artificial insemination as a method of controlled sperm delivery and show that sperm swimming velocity is the primary determinant of fertilization success when ejaculates from two males compete to fertilize a female's eggs. By contrast, we found no evidence that sperm length had any effect on siring success. We also found no evidence that pre- and postcopulatory sexual traits were phenotypically integrated in this species, suggesting that the previous observation that reproductive skew favours males with high mating rates is unlikely to be due to any direct association between sperm quality and male sexual ornamentation.

  19. Effect of Actinobacteria as a single cell protein on growth performance of Xiphophorus helleri

    Directory of Open Access Journals (Sweden)

    Selvakumar Dharmaraj

    2014-12-01

    Full Text Available The potential of Marine Actinobacteria particularly Streptomyces as a single cell protein (SCP feed for the growth of ornamental fish, Xiphophorus helleri has been investigated. The Streptomyces strains used as SCP were isolated from the marine sponges, namely Callyspongia diffusa, Mycale mytilorum, Tedania anhelans and Dysidea fragilis. Six SCP feeds were prepared and their effects were compared with those of control diet. After 30 days of feeding trials, the growth parameters including absolute growth rate, specific growth rate and feed conversion efficiency were found to be significantly (P<0.001 higher in groups that received SCP feed than those of control one, whereas feed conversion ratio was lower. Thus it was found that in addition to being effective antibiotic agents against harmful pathogens, Streptomyces could also promote the growth of fish effectively. Marine Actinobacteria, particularly Streptomyces, could play an important role as a single cell protein (SCP in aquaculture nutrition and is a promising microbe for the development of marine biotechnology.

  20. Evaluation of Streptomyces as a Probiotic Feed for the Growth of Ornamental Fish Xiphophorus helleri

    Directory of Open Access Journals (Sweden)

    Kandasamy Dhevendaran

    2010-01-01

    Full Text Available The potential of Streptomyces as a probiotic feed for the growth of ornamental fish Xiphophorus helleri has been investigated. The Streptomyces strains used as probiotics were isolated from the marine sponges, namely Callyspongia diffusa, Mycale mytilorum, Tedania anhelans and Dysidea fragilis. Seven probiotic feeds were prepared and their effects were compared with those of control diet containing no probiotics. After 50 days of feeding trials, the growth parameters, namely absolute growth rate, specific growth rate, relative growth rate and feed conversion efficiency were found to be significantly (p<0.05 higher in groups that received probiotic feed additive than in the control, whereas feed conversion ratio was lower. The fish fed with probiotic feed showed significant improvement in length than the fish fed with control feed. Thus it was found that in addition to being effective antibiotic agents against harmful pathogens, Streptomyces could also promote the growth of fish effectively. Marine Actinobacteria, particularly Streptomyces, could thus be a promising probiotic in aquaculture.

  1. Observations on white and yellow venoms from an individual southern Pacific rattlesnake (Crotalus viridis helleri).

    Science.gov (United States)

    Johnson, E K; Kardong, K V; Ownby, C L

    1987-01-01

    Biochemical differences in white and yellow venoms produced in the separate venom glands of an individual southern Pacific rattlesnake (Crotalus viridis helleri) were investigated. Compared to the yellow venom, the white venom contained fewer low molecular weight components and was considerably less toxic. Although the exact LD50 was not determined, the white venom did not produce toxic effects in mice when injected i.v. at concentrations up to 10 mg/kg. The i.v. LD50 of the yellow venom was approximately 1.6 mg/kg. Both white and yellow venoms had hemorrhagic activity, but the white venom caused less intradermal hemorrhage in mice. No L-amino acid oxidase activity was measured in the white venom and protease and phospholipase A2 activities of the white venom were much less than in the yellow venom. The white and yellow venoms both produced myonecrosis at 1, 3 and 24 hr after i.m. injection into mice, however, there were some qualitative differences in the myonecrosis produced. When the venom samples were reacted against Wyeth's polyvalent (Crotalidae) antivenom using immunodiffusion, three precipitin bands formed against the yellow venom, whereas only one formed against the white venom. When reacted against an antiserum to myotoxin alpha from C. viridis viridis venom, both the white and yellow venoms produced one precipitin band each.

  2. Black Phosphorus Quantum Dots for Hole Extraction of Typical Planar Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Wei; Li, Kaiwen; Wang, Yao; Feng, Xiyuan; Liao, Zhenwu; Su, Qicong; Lin, Xinnan; He, Zhubing

    2017-02-02

    Black phosphorus, famous as two-dimensional (2D) materials, shows such excellent properties for optoelectronic devices such as tunable direct band gap, extremely high hole mobility (300-1000 cm(2)/(V s)), and so forth. In this Letter, facile processed black phosphorus quantum dots (BPQDs) were successfully applied to enhance hole extraction at the anode side of the typical p-i-n planar hybrid perovskite solar cells, which remarkably improved the performance of devices with photon conversion efficiency ramping up from 14.10 to 16.69%. Moreover, more detailed investigations by c-AFM, SKPM, SEM, hole-only devices, and photon physics measurements discover further the hole extraction effect and work mechanism of the BPQDs, such as nucleation assistance for the growth of large grain size perovskite crystals, fast hole extraction, more efficient hole transfer, and suppression of energy-loss recombination at the anode interface. This work definitely paves the way for discovering more and more 2D materials with high electronic properties to be used in photovoltaics and optoelectronics.

  3. Stable semiconductor black phosphorus (BP)@titanium dioxide (TiO2) hybrid photocatalysts.

    Science.gov (United States)

    Lee, Hyun Uk; Lee, Soon Chang; Won, Jonghan; Son, Byung-Chul; Choi, Saehae; Kim, Yooseok; Park, So Young; Kim, Hee-Sik; Lee, Young-Chul; Lee, Jouhahn

    2015-03-03

    Over the past few decades, two-dimensional (2D) and layered materials have emerged as new fields. Due to the zero-band-gap nature of graphene and the low photocatalytic performance of MoS2, more advanced semiconducting 2D materials have been prompted. As a result, semiconductor black phosphorus (BP) is a derived cutting-edge post-graphene contender for nanoelectrical application, because of its direct-band-gap nature. For the first time, we report on robust BP@TiO2 hybrid photocatalysts offering enhanced photocatalytic performance under light irradiation in environmental and biomedical fields, with negligible affected on temperature and pH conditions, as compared with MoS2@TiO2 prepared by the identical synthesis method. Remarkably, in contrast to pure few layered BP, which, due to its intrinsic sensitivity to oxygen and humidity was readily dissolved after just several uses, the BP@TiO2 hybrid photocatalysts showed a ~92% photocatalytic activity after 15 runs. Thus, metal-oxide-stabilized BP photocatalysts can be practically applied as a promising alternative to graphene and MoS2.

  4. Influence of space flight conditions on phenotypes and functionality of nephritic immune cells of fish (Xiphophorus helleri)

    Science.gov (United States)

    Piepenbreier, K.; Renn, J.; Fischer, R.; Goerlich, R.

    Microgravity is considered to directly perturb a number of immunological and haematological parameters in mammalians, and therefore is of fundamental importance in space biology. The viviparous teleost Xiphophorus helleri (swordtail) was used as a "lower vertebrate model" in the shuttle missions STS-89 (Small Payload) and STS-90 (NEUROLAB). When developing a regenerative aquatic system (like the Closed Equilibrated Biological Aquatic System - C.E.B.A.S.) to produce food fish on long-term space missions, we have to make sure that microgravity and other space conditions do not endanger the animals' health. Immunological aspects are very important in this field. The major research targets were immunological research of accessory (monocytes) and immunoreactive cells (lymphocytes) of the kidney from X. helleri, which were exposed to microgravity in comparison to ground control animals. Cell cycle analysis of the main haematopoetic organ (kidney), cell behaviour, cell cytochemistry, phagocytic ability and in vitro stimulation of immunoreactive cells from kidney after return to earth were investigated. The results are also important for basic research in immunotoxicology and developmental biology. As there is an interrelation between immune cells and bone metabolism, the investigations are also interesting for space medicine. Acknowledgement: This work was supported by the German Aerospace Center (DLR) (50 WB 9412, 50 WB 9996) and the National Aeronautics and Space Administration (NASA 98HEDS-02-418)

  5. Accretion Disks Around Binary Black Holes: A Simple GR-Hybrid Evolution Model

    CERN Document Server

    Shapiro, Stuart L

    2013-01-01

    We consider a geometrically thin, Keplerian disk in the orbital plane of a binary black hole (BHBH) consisting of a spinning primary and low-mass secondary (mass ratio q < 1). To account for the principle effects of general relativity (GR), we propose a modification of the standard Newtonian evolution equation for the (orbit-averaged) time-varying disk surface density. In our modified equation the viscous torque in the disk is treated in full GR, while the tidal torque is handled in the Newtonian limit. Our GR-hybrid treatment is reasonable because the tidal torque is concentrated near the orbital radius of the secondary and is most important prior to binary-disk decoupling, when the orbital separation is large and resides in the weak-field regime. The tidal torque on the disk diminishes during late merger and vanishes altogether following merger. By contrast, the viscous torque drives the flow into the strong-field region and onto the primary during all epochs. Following binary coalescence, the viscous to...

  6. On the Hybrid F1 Characteristics of Physiology, Biochemistry, Product Quality and Resistance to Black Shank in Oriental Tobacco

    Directory of Open Access Journals (Sweden)

    Chen X

    2014-12-01

    Full Text Available Experiments were conducted from 1996 to 1998 at the Hefei Institute of Economics and Technology and at the Oriental Experimental Station of the Zhejiang Province (China. Seven F1 hybrids and three parental varieties of Oriental tobaccos were evaluated for the characteristics of photosynthetic and transpiration rates, esterase isozymes, resistance to black shank, quality and product potential from the 1996-1998 growing seasons. Tobacco leaves had higher photosynthetic rates and many differences among genotypes in the early stage of plant vigorous growth compared with more mature leaves. However, transpiration rates were lower in the younger leaves and greater in the more mature leaves. All the entries had four common bands (B1, B3, B4 and B6 of the esterase isoenzymes. Differences between entries resulted from in having or not having the B2 and B5 bands and color intensity differences of all the bands. These differences could be used to identify individual entries. The F1hybrids Samsun X Toy and Samsun X Argjiro, compared with the CK Samsun control, had obvious heterotic vigor in the characteristics of product, for yield, quality and resistance to black shank. The F1 hybrid Samsun X Toy maintained higher photosynthetic and transpiration rates in the two growth stages compared to other entries. However, the F1hybrid Samsun X Argjiro had higher photosynthetic rates and lower transpiration rates in the early growth stage and the two rates were lower in the later stage, but it maintained higher photosynthetic rates for the whole growth stage. Net photosynthetic rates had a significant positive correlation with yield product, quality and resistance to black shank of the Oriental tobacco F1hybrids.

  7. Metabolic Characteristics in Meal of Black Rapeseed and Yellow-Seeded Progeny of Brassica napus–Sinapis alba Hybrids

    Directory of Open Access Journals (Sweden)

    Jinjin Jiang

    2015-11-01

    Full Text Available Breeding of yellow-seeded rapeseed (Brassica napus is preferred over black-seeded rapeseed for the desirable properties of the former. This study evaluated the metabolites and nutritive values of black-seeded rapeseed meal and yellow-seeded meal from the progeny of a B. napus–Sinapis alba hybrid. Yellow-seed meal presented higher protein (35.46% vs. 30.29%, higher sucrose (7.85% vs. 7.29%, less dietary fiber (26.19% vs. 34.63% and crude fiber (4.56% vs. 8.86%, and less glucosinolates (22.18 vs. 28.19 μmol/g than black-seeded one. Amounts of ash (3.65% vs. 4.55%, phytic acid (4.98% vs. 5.60%, and total polyphenols (2.67% vs. 2.82% were decreased slightly in yellow-seeded meal compared with black-seeded meal. Yellow-seeded meal contained more essential amino acids than black-seeded meal. Levels of the mineral elements Fe, Mn, and Zn in yellow-seeded meal were higher than black-seeded meal. By contrast, levels of P, Ca, and Mg were lower in yellow-seeded meal. Moreover, yellow-seeded meal showed lower flavonol (kaempferol, quercetin, isorhamnetin, and their derivatives content than black-seeded meal. Comparison of metabolites between yellow and black rapeseed confirmed the improved nutritional value of meal from yellow-seeded B. napus, and this would be helpful to the breeding and improvement of rapeseed for animal feeding.

  8. Application of Black Pearl carbon-supported WO 3 nanostructures as hybrid carriers for electrocatalytic RuSe x nanoparticles

    Science.gov (United States)

    Miecznikowski, Krzysztof; Kulesza, Pawel J.; Fiechter, Sebastian

    2011-07-01

    RuSe x electrocatalytic nanoparticles were deposited onto hybrid carriers composed of Black Pearl carbon-supported tungsten oxide; and the resulting system's electrochemical activity was investigated during oxygen reduction reaction. The tungsten oxide-utilizing and RuSe x nanoparticle-containing materials were characterized using transmission electron microscopy, X-ray diffraction and electrochemical diagnostic techniques such as cyclic voltammetry and rotating ring-disk voltammetry. Application of Black Pearl carbon carriers modified with ultra-thin films of WO 3 as matrices (supports) for RuSe x catalytic centers results during electroreduction of oxygen in 0.5 mol dm -3 H 2SO 4 (under rotating disk voltammetric conditions) in the potential shift of ca. 70 mV towards more positive values relative to the behavior of the analogous WO 3-free system. Also the percent formation (at ring in the rotating ring-disk voltammetry) of the undesirable hydrogen peroxide has been decreased approximately twice by utilizing WO 3-modified carbon carriers. The results are consistent with the bifunctional mechanism in which oxygen reduction is initiated at RuSe x centers and the hydrogen peroxide intermediate is reductively decomposed at reactive WO 3-modified Black Pearl supports. The electrocatalytic activity of the system utilizing WO 3-modified Black Pearl supports has been basically unchanged upon addition of acetic acid, formic acid or methyl formate to the sulfuric acid supporting electrolyte.

  9. Rheological and electrical properties of hybrid nanocomposites of epoxy resins filled with graphite nanoplatelets and carbon black.

    Science.gov (United States)

    Truong, Quang-Trung; Lee, Seon-Suk; Lee, Dai-Soo

    2011-02-01

    Graphite nanoplatelets (GNP) were prepared by microwave irradiation of natural graphites intercalated with ferric chloride in nitromethane (GIC). Intercalated structure of GIC was confirmed by X-ray diffraction patterns. SEM images of GIC after microwave irradiation showed the exfoliation of GIC, the formation of GNPs. Hybrid nanocomposites of bisphenol-A type epoxy resins filled with GNP and a conductive carbon black (CB) were prepared and rheological and electrical properties of the nanocomposites were investigated. Viscosity and electrical surface resistivity of the nanocomposites showed minima at certain mixtures of GNP and CB in the epoxy resins.

  10. A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    Yuli Chen

    2014-01-01

    Full Text Available The electrical percolation of polymer-matrix composites (PMCs containing hybrid fillers of carbon nanotubes (CNTs and carbon black (CB is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

  11. Design and synthesis of palladium/graphitic carbon nitride/carbon black hybrids as high-performance catalysts for formic acid and methanol electrooxidation

    Science.gov (United States)

    Qian, Huayu; Huang, Huajie; Wang, Xin

    2015-02-01

    Here we report a facile two-step method to synthesize high-performance palladium/graphitic carbon nitride/carbon black (Pd/g-C3N4/carbon black) hybrids for electrooxidizing formic acid and methanol. The coating of g-C3N4 on carbon black surface is realized by a low-temperature heating treatment, followed by the uniform deposition of palladium nanoparticles (Pd NPs) via a wet chemistry route. Owning to the significant synergistic effects of the individual components, the preferred Pd/g-C3N4/carbon black electrocatalyst exhibits exceptional forward peak current densities as high as 2155 and 1720 mA mg-1Pd for formic acid oxidation in acid media and methanol oxidation in alkaline media, respectively, far outperforming the commercial Pd-C catalyst. The catalyst also shows reliable stability, demonstrating that the newly-designed hybrids have great promise in constructing high-performance portable fuel cell systems.

  12. BROWN, BLACK, YELLOW, WHITE: FILIPINO MUSICIANSHIP IN HONG KONG AND THEIR HYBRIDIZED SOCIABILITY

    Directory of Open Access Journals (Sweden)

    Lee William Watkins

    2010-06-01

    Full Text Available This article addresses the issue of hybridity as one manifested in the everyday experiences of migrant Filipino musicians in Hong Kong, with a particular emphasis on their differences in a dialectic of the self and other as mobilised in performance, and, as a continuum woven into their racial colour and various social statuses. Where hybridity in music is the concern, most studies focus on hybridity as a matter of aesthetics, while in nonmusical areas, hybridity is addressed in the context of the relationship between colonized and colonizer during western imperialism, and between migrant and host in the contemporary age. This article combines these two areas: it will briefly include, but also move beyond the concern with aesthetics and propose hybridity through the cultural analysis of musical performance more as a form of social action resulting from colonialism, neocolonialism and transnationalism.

  13. A hybrid approach to black hole perturbations from extended matter sources

    CERN Document Server

    Ferrari, V; Rezzolla, L; Ferrari, Valeria; Gualtieri, Leonardo; Rezzolla, Luciano

    2006-01-01

    We present a new method for the calculation of black hole perturbations induced by extended sources in which the solution of the nonlinear hydrodynamics equations is coupled to a perturbative method based on Regge-Wheeler/Zerilli and Bardeen-Press-Teukolsky equations when these are solved in the frequency domain. In contrast to alternative methods in the time domain which may be unstable for rotating black-hole spacetimes, this approach is expected to be stable as long as an accurate evolution of the matter sources is possible. Hence, it could be used under generic conditions and also with sources coming from three-dimensional numerical relativity codes. As an application of this method we compute the gravitational radiation from an oscillating high-density torus orbiting around a Schwarzschild black hole and show that our method is remarkably accurate, capturing both the basic quadrupolar emission of the torus and the excited emission of the black hole.

  14. Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

    Science.gov (United States)

    In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

  15. Hybrid Black Hole Algorithm for Bi-Criteria Job Scheduling on Parallel Machines

    Directory of Open Access Journals (Sweden)

    Kawal Jeet

    2016-04-01

    Full Text Available Nature-inspired algorithms are recently being appreciated for solving complex optimization and engineering problems. Black hole algorithm is one of the recent nature-inspired algorithms that have obtained inspiration from black hole theory of universe. In this paper, four formulations of multi-objective black hole algorithm have been developed by using combination of weighted objectives, use of secondary storage for managing possible solutions and use of Genetic Algorithm (GA. These formulations are further applied for scheduling jobs on parallel machines while optimizing bi-criteria namely maximum tardiness and weighted flow time. It has been empirically verified that GA based multi-objective Black Hole algorithms leads to better results as compared to their counterparts. Also the use of combination of secondary storage and GA further improves the resulting job sequence. The proposed algorithms are further compared to some of the existing algorithms, and empirically found to be better. The results have been validated by numerical illustrations and statistical tests.

  16. Molecular cloning and expression of a heat-shock cognate 70 (hsc70) gene from swordtail fish (Xiphophorus helleri)

    Institute of Scientific and Technical Information of China (English)

    LI Ningqiu; FU Xiaozhe; HAN Jingang; SHI Cunbin; HUANG Zhibin; WU Shuqin

    2013-01-01

    Heat shock proteins are a family of molecular chaperones that are involved in many aspects of protein homeostasis.In the present study,a full-length cDNA,encoding the constitutively expressed 70-kDa heat shock cognate protein (Hsc70),was isolated from swordtail fish (Xiphophorus helleri) and designated as XheHsc70.The Xhehsc70 cDNA was 2 104 bp long with an open reading frame of 1 941 bp,and it encoded a protein of 646 amino acids with a theoretical molecular weight of 70.77 kDa and an isoelectric point of 5.04.The deduced amino acid sequence shared 94.1%-98.6% identities with the Hsc70s from a number of other fish species.Tissue distribution results show that the Xhehsc70 mRNA was expressed in brain,heart,head kidney,kidney,spleen,liver,muscle,gill,and peripheral blood.After immunization with formalin-killed Vibrio alginolyticus cells there was a significant increase in the Xhehsc70 rnRNA transcriptional level in the head kidney of the vaccinated fish compared with in the control at 6,12,24,and 48 h as shown by quantitative real time RT-PCR.Based on an analysis of the amino acid sequence of XheHsc70,its phylogeny,and Xhehsc70 mRNA expression,XheHsc70 was identified as a member of the cytoplasmic Hsc70 (constitutive) subfamily of the Hsp70 family of heat shock proteins,suggesting that it may play a role in the immune response.The Xhehsc70 cDNA sequence reported in this study was submitted to GenBank under the accession number JF739182.

  17. Molecular cloning and expression of a heat-shock cognate 70 (hsc70) gene from swordtail fish ( Xiphophorus helleri)

    Science.gov (United States)

    Li, Ningqiu; Fu, Xiaozhe; Han, Jingang; Shi, Cunbin; Huang, Zhibin; Wu, Shuqin

    2013-07-01

    Heat shock proteins are a family of molecular chaperones that are involved in many aspects of protein homeostasis. In the present study, a full-length cDNA, encoding the constitutively expressed 70-kDa heat shock cognate protein (Hsc70), was isolated from swordtail fish ( Xiphophorus helleri) and designated as XheHsc70. The Xhehsc70 cDNA was 2 104 bp long with an open reading frame of 1 941 bp, and it encoded a protein of 646 amino acids with a theoretical molecular weight of 70.77 kDa and an isoelectric point of 5.04. The deduced amino acid sequence shared 94.1%-98.6% identities with the Hsc70s from a number of other fish species. Tissue distribution results show that the Xhehsc70 mRNA was expressed in brain, heart, head kidney, kidney, spleen, liver, muscle, gill, and peripheral blood. After immunization with formalin-killed Vibrio alginolyticus cells there was a significant increase in the Xhehsc70 mRNA transcriptional level in the head kidney of the vaccinated fish compared with in the control at 6, 12, 24, and 48 h as shown by quantitative real time RT-PCR. Based on an analysis of the amino acid sequence of XheHsc70, its phylogeny, and Xhehsc70 mRNA expression, XheHsc70 was identified as a member of the cytoplasmic Hsc70 (constitutive) subfamily of the Hsp70 family of heat shock proteins, suggesting that it may play a role in the immune response. The Xhehsc70 cDNA sequence reported in this study was submitted to GenBank under the accession number JF739182.

  18. Generation of Five New Musa Hybrids With Resistance To Black Sigatoka and High Yield

    Directory of Open Access Journals (Sweden)

    Ricardo Hernandez

    2007-01-01

    Full Text Available The ability to identify genetic variation is indispensable to effective management and use of genetic resources. This work is the first approach concerning to generation and genetic differentiation of new Musa hybrid lines obtained in INIVIT (Cuba, crossing Musa acuminata male diploid (AA x female triploid (ABB, genotypes selected by their resistant character to pests and diseases. From the obtained hybrids, only five were chosen because of their agronomic behavior and were genetically discriminated among them and also respect to the commercial clone FHIA-18 by AFLP polymorphism. Thanks to this prior genetic characterization Musa breeding programs could be consistently dinamised.

  19. Evolution of Debris of a Tidally Disrupted Star by a Massive Black Hole Development of a Hybrid Scheme of the SPH and TVD Methods

    CERN Document Server

    Lee, H M; Lee, Hyung Mok; Kim, Sungsoo S.

    1996-01-01

    The evolution of the stellar debris after tidal disruption due to the super massive black hole's tidal force is difficult to solve numerically because of the large dynamical range of the problem. We developed an SPH (Smoothed Particle Hydrodynamics) - TVD (Total Variation Diminishing) hybrid code in which the SPH is used to cover a widely spread debris and the TVD is used to compute the stream collision more accurately. While the code in the present form is not sufficient to obtain desired resoultion, it could provide a useful tool in studying the aftermath of the stellar disruption by a massive black hole.

  20. Activity of the thyroid and the pituitary gland in the viviparous Cyprinodonts Lebistes reticulatus (Peters), Xiphophorus helleri Heckel and Xiphophorus maculatus Günther during the development of the gonopodium

    NARCIS (Netherlands)

    Stolk, A.

    1959-01-01

    A description is given of the activity of the thyroid and of the pituitary gland during the development of the gonopodium in the viviparous Cyprinodonts Lebistes reticulatus (Peters), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Günther). During this process the thyroid gland and the glan

  1. The skeletal defects and inheritance in dwarf mutants of Xiphophorus helleri%剑尾鱼侏儒突变的骨骼异常及其遗传

    Institute of Scientific and Technical Information of China (English)

    李凯彬; 刘春; 常藕琴; 王芳; 马必勇; 吴淑勤

    2011-01-01

    Dwarf mutant of Xiphophorus helleri is used as the female parent to cross normal body type male, showing that dwarf individual can be identified in the offspring and such character is inheritable. The body type pattern of offspring exhibits a successive distribution, similar to male or female parent, in addition to intermediate type. It is less likely to discriminate the individual phenotype by using a clear definition. Dwarf mutants of Xiphophorus helleri manifest as short bloated body, clumsy swimming, and significantly altered trunk length-height ratio. This mutation retards fish growth and compromises the reproductivity. The self-cross and back-cross of F1 progenies also result in a successive distribution in body type among various crosses. The dwarf characteristic in X. helleri is not inherited in a simple alternative manner, which affects a group of characters rather than a single character. The consistency with primary feature of quantitative character suggests that such mutation may be controlled by multiple quantitative character genes. The skeletal morphological analysis indicates that the spinal length of X. helleri mutant is significantly shortened, whereas the number of vertebrae is comparable to that of normal individual, ranging from 26 to 29. The dramatically shortened vertebral body in the mutant impairs the longitudinal development of spine. The neural spine and hemal spine are in a tight arrangement,whose development is also significantly retarded. Therefore,the dwarf mutation in X. helleri is caused by the developmental defect in vertebral column, and the vertebral malformation underlies the body type alteration anatomically. As fish is representative of lower-ranking vertebrate,the dwarf swordtail mutant is reproducible,and the character is inheritable and closely associated with spinal development. Such mutant is a potential fish model for the systemical research.%以侏儒剑尾鱼为母本,与正常体型的雄性剑尾鱼进行交配,发

  2. Layer-by-layer self-assembled mesoporous PEDOT-PSS and carbon black hybrid films for platinum free dye-sensitized-solar-cell counter electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Koji; Shiratori, Seimei [School of Integrated Design Engineering, Keio University, Yokohama 223-8522 (Japan)

    2011-05-13

    A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.

  3. Layer-by-layer self-assembled mesoporous PEDOT-PSS and carbon black hybrid films for platinum free dye-sensitized-solar-cell counter electrodes.

    Science.gov (United States)

    Kitamura, Koji; Shiratori, Seimei

    2011-05-13

    A thin film of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT-PSS), which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was prepared using the layer-by-layer self-assembly method (LbL). The film is highly adhesive to the substrate and has a controllable thickness. Therefore, the PEDOT-PSS film prepared using LbL is expected have high performance and durability as a counter electrode. Moreover, when carbon black was added to the PEDOT-PSS solution, highly mesoporous PEDOT-PSS and carbon black hybrid films were obtained. These films showed high cathodic activity. In this study, we investigated the change in morphology in the obtained film with increasing carbon black content, and the influence of the porosity and thickness on the performance of the cells. In this study, a Pt-free counter electrode with performance similar to that of Pt-based counter electrodes was successfully fabricated. The achieved efficiency of 4.71% was only a factor of 8% lower than that of the cell using conventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.

  4. OBSERVATION ON THE HISTOLOGY AND ULTRASTRUCTURE OF THE KIDNEY IN Xiphophorus helleri%剑尾鱼肾脏组织的超微结构观察

    Institute of Scientific and Technical Information of China (English)

    林国辉; 邱玫; 方展强

    2011-01-01

    Histology and ultrastructure of the kidney in Swordtails (Xiphophorus helleri) were studied with microscope and transmission electron microscope.Similar to other teleost, the mesonephros was consisted of renal corpuscle and renal tubules.Renal corpuscles were interspersed in the kidney.The renal tubules were composed of the neck tubule, first and second proximal tubule, distal tubule and the collecting tubule.Lymphoid tissues, including Lymphocyte, Monocyte and Melano - macrophage, were differentiated in the kidney under electron microscope.As a multifunction organ, the characteristic of structure and ultrastructure of the kidney in fish were also discussed in this paper.%应用光镜和透射电镜对剑尾鱼肾脏的组织的超微结构观察的结果表明:肾脏结构与其它硬骨鱼类相似.可以区分淋巴细胞、单核细胞和黑色素巨噬细胞等类型.该文还讨论了肾脏作为鱼类体内一个具有多种生理功能复合器官的结构特点.

  5. Acute toxicity of trichlorofon on four viviparous fish:Poecilia latipinna, Poecilia reticulata, Gambusia holbrooki and Xiphophorus helleri (Cyprinodontiformes:Poecilidae)

    Institute of Scientific and Technical Information of China (English)

    Mohammad Forouhar Vajargah; Aliakbar Hedayati

    2014-01-01

    Objective: To determine toxicity and safety margins of trichlorofon in different trichlorofon toxicity has a large variation in the susceptibility of different species. species as Methods: In this research, four viviparous aquarium fish were exposed to trichlorofon for 96 h. sLaCm50 polfe s2 4w he,r e4 8e xhp, o7s2e dh taon ddi f9f6e rhe nwt ecroen actetnaitnraetdio bnys opfr otbriict halnoraolyfosnis software SPSS Version 16. Fish and mortality were recorded, separately. (5, 10, 20 and 40 mg/L) for 96 h Results: The 96 h LC50 of Poecilia latipinna, Poecilia reticulata, Gambusia holbrooki and Xiphophorus helleri were 9.80, 9.80, 9.95 and 7.99 mg/L, respectively. Conclusions: According to the results of this research, LC50 values indicated Xiphophorus hrooki, with a few differences, was the most sensitive elleri wspaesc itehse cmomospt arreesdi swtaitnht tahned f iGshaems beuxsaima ihnoeldb.

  6. The NINJA-2 catalog of hybrid post-Newtonian/numerical-relativity waveforms for non-precessing black-hole binaries

    CERN Document Server

    Ajith, P; Brown, Duncan A; Brügmann, Bernd; Buchman, Luisa T; Cadonati, Laura; Campanelli, Manuela; Chu, Tony; Etienne, Zachariah B; Fairhurst, Stephen; Hannam, Mark; Healy, James; Hinder, Ian; Husa, Sascha; Kidder, Lawrence E; Krishnan, Badri; Laguna, Pablo; Liu, Yuk Tung; London, Lionel; Lousto, Carlos O; Lovelace, Geoffrey; MacDonald, Ilana; Marronetti, Pedro; Mohapatra, Satya; Mösta, Philipp; Müller, Doreen; Mundim, Bruno C; Nakano, Hiroyuki; Ohme, Frank; Paschalidis, Vasileios; Pekowsky, Larne; Pollney, Denis; Pfeiffer, Harald P; Ponce, Marcelo; Pürrer, Michael; Reifenberger, George; Reisswig, Christian; Santamaría, Lucía; Scheel, Mark A; Shapiro, Stuart L; Shoemaker, Deirdre; Sopuerta, Carlos F; Sperhake, Ulrich; Szilágyi, Béla; Taylor, Nicholas W; Tichy, Wolfgang; Tsatsin, Petr; Zlochower, Yosef

    2012-01-01

    The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search and parameter-estimation algorithms using numerically generated waveforms, and to foster closer collaboration between the numerical relativity and data analysis communities. The first NINJA project used only a small number of injections of short numerical-relativity waveforms, which limited its ability to draw quantitative conclusions. The goal of the NINJA-2 project is to overcome these limitations with long post-Newtonian - numerical relativity hybrid waveforms, large numbers of injections, and the use of real detector data. We report on the submission requirements for the NINJA-2 project and the construction of the waveform catalog. Eight numerical relativity groups have contributed 63 hybrid waveforms consisting of a numerical portion modelling the late ...

  7. Sandwiched Thin-Film Anode of Chemically Bonded Black Phosphorus/Graphene Hybrid for Lithium-Ion Battery.

    Science.gov (United States)

    Liu, Hanwen; Zou, Yuqin; Tao, Li; Ma, Zhaoling; Liu, Dongdong; Zhou, Peng; Liu, Hongbo; Wang, Shuangyin

    2017-09-01

    A facile vacuum filtration method is applied for the first time to construct sandwich-structure anode. Two layers of graphene stacks sandwich a composite of black phosphorus (BP), which not only protect BP from quickly degenerating but also serve as current collector instead of copper foil. The BP composite, reduced graphene oxide coated on BP via chemical bonding, is simply synthesized by solvothermal reaction at 140 °C. The sandwiched film anode used for lithium-ion battery exhibits reversible capacities of 1401 mAh g(-1) during the 200th cycle at current density of 100 mA g(-1) indicating superior cycle performance. Besides, this facile vacuum filtration method may also be available for other anode material with well dispersion in N-methyl pyrrolidone (NMP). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. No suggestion of hybridization between the vulnerable black-faced impala (Aepyceros melampus petersi) and the common impala (A. m. melampus) in Etosha National Park, Namibia

    DEFF Research Database (Denmark)

    Lorenzen, Eline D.; Siegismund, Hans Redlef

    2004-01-01

    Aepyceros melampus petersi, Bovidae, conservation, hybridization, introgression following translocation, microsatellites......Aepyceros melampus petersi, Bovidae, conservation, hybridization, introgression following translocation, microsatellites...

  9. [Effect of oregano essential oil on the engraftment and development of Lewis carcinoma in F1 DBA C57 black hybrid mice].

    Science.gov (United States)

    Misharina, T A; Burlakova, E B; Fatkullina, L D; Alinkina, E S; Vorob'eva, A K; Medvedeva, I B; Erokhin, V N; Semenov, V A; Nagler, L G; Kozachenko, A I

    2013-01-01

    The effect of a low uptake dose of oregano essential oil with drinking water for three months (Origanum vulgare L.) on the degree of Lewis carcinoma engraftment and some parameters of oxidative stress has been studied in vivo using F1 DBA C57 Black hybrid mice. Oregano essential oil has been established to possess an anticancer activity. The degree of tumor engraftment decreased by 1.8 times, its size decreased by 1.5 times, and the development of tumor was significantly suppressed in sick mice under the effect of oregano essential oil. It was found that the uptake of essential oil did not affect the intensity of lipid peroxidation in the brain of mice and resulted in a significantly (by 36%) decreased content of secondary lipid oxidation products in the liver as shown in a reaction with thiobarbituric acid as compared to control subjects. The activity of antioxidant enzymes was found to increase after three months of essential oil uptake (by 1.5-3 times) as compared to the control group. This effect of essential oil supports the presence of bioantioxidant properties in this essential oil.

  10. Hybridity in Disgrace

    Institute of Scientific and Technical Information of China (English)

    刘建平

    2015-01-01

    John Maxwell Coetzee's masterpiece-Disgrace is the representative work about post colonialism.The novel describes a series of disgraceful events happened between the white and the black in the post apartheid South Africa.The famous literature theory-hybridity of Homi K.Bhabha is the very key theory to analyze the work.In post apartheid South Africa,hybridity is the only way for the white and the black to coexist.

  11. Hybridization effects and genetic diversity of the common and black-tufted marmoset (Callithrix jacchus and Callithrix penicillata) mitochondrial control region.

    Science.gov (United States)

    Malukiewicz, Joanna; Boere, Vanner; Fuzessy, Lisieux F; Grativol, Adriana D; French, Jeffrey A; de Oliveira e Silva, Ita; Pereira, Luiz C M; Ruiz-Miranda, Carlos R; Valença, Yuri M; Stone, Anne C

    2014-12-01

    Hybridization is continually documented in primates, but effects of natural and anthropogenic hybridization on biodiversity are still unclear and differentiating between these contexts remains challenging in regards to primate evolution and conservation. Here, we examine hybridization effects on the mitochondrial DNA (mtDNA) control region of Callithrix marmosets, which provide a unique glimpse into interspecific mating under distinct anthropogenic and natural conditions. DNA was sampled from 40 marmosets along a 50-km transect from a previously uncharacterized hybrid zone in NE Brazil between the ranges of Callithrix jacchus and Callithrix penicillata. DNA was also collected from 46 marmosets along a 30-km transect in a hybrid zone in Rio de Janeiro state, Brazil, where exotic marmosets appeared in the 1980s. Combining Callithrix DNA sampled inside and outside of these hybrid zones, phylogenetic and network analyses show C. jacchus and C. penicillata being parental species to sampled hybrids. We expand limited Callithrix population genetics work by describing mtDNA diversity and demographic history of these parental species. We show ancient population expansion in C. jacchus and historically constant population size in C. penicillata, with the latter being more genetically diverse than the former. The natural hybrid zone contained higher genetic diversity relative to the anthropogenic zone. While our data suggest hybrid swarm formation within the anthropogenic zone due to removed physical reproductive barriers, this pattern is not seen in the natural hybrid zone. These results suggest different genetic dynamics within natural and anthropogenic hybridization contexts that carry important implications for primate evolution and conservation.

  12. Finding consistency between different views of the absorption enhancement of black carbon: An observationally constrained hybrid model to support a transition in optical properties with mass fraction

    Science.gov (United States)

    Coe, H.; Allan, J. D.; Whitehead, J.; Alfarra, M. R. R.; Villegas, E.; Kong, S.; Williams, P. I.; Ting, Y. C.; Haslett, S.; Taylor, J.; Morgan, W.; McFiggans, G.; Spracklen, D. V.; Reddington, C.

    2015-12-01

    The mixing state of black carbon is uncertain yet has a significant influence on the efficiency with which a particle absorbs light. In turn, this may make a significant contribution to the uncertainty in global model predictions of the black carbon radiative budget. Previous modelling studies that have represented this mixing state using a core-shell approach have shown that aged black carbon particles may be considerably enhanced compared to freshly emitted black carbon due to the addition of co-emitted, weakly absorbing species. However, recent field results have demonstrated that any enhancement of absorption is minor in the ambient atmosphere. Resolving these differences in absorption efficiency is important as they will have a major impact on the extent to which black carbon heats the atmospheric column. We have made morphology-independent measurements of refractory black carbon mass and associated weakly absorbing material in single particles from laboratory-generated diesel soot and black carbon particles in ambient air influenced by traffic and wood burning sources and related these to the optical properties of the particles. We compared our calculated optical properties with optical models that use varying mixing state assumptions and by characterising the behaviour in terms of the relative amounts of weakly absorbing material and black carbon in a particle we show a sharp transition in mixing occurs. We show that the majority of black carbon particles from traffic-dominated sources can be treated as externally mixed and show no absorption enhancement, whereas models assuming internal mixing tend to give the best estimate of the absorption enhancement of thickly coated black carbon particles from biofuel or biomass burning. This approach reconciles the differences in absorption enhancement previously observed and offers a systematic way of treating the differences in behaviour observed.

  13. 育肥性能分析大凉山黑猪杂交F1代%Fattening Performance Analysis of Daliangshan Black Pig′s Hybridization F1

    Institute of Scientific and Technical Information of China (English)

    黄剑锋; 黄卫平

    2016-01-01

    大凉山黑猪生长速度慢,用杜洛克、巴克夏等优质公猪杂交改良后,育肥性能有了明显提高。采用生长曲线拟合与回归分析可以科学估算大凉山黑猪及其F1代的出栏时间,其中纯种黑猪的拐点体重为71.6 kg、出栏时间为193.4 d,杜杂黑猪为90.3 kg、200.4 d,巴杂黑猪为89.7 kg、198.6 d。%The growth speed of Daliangshan black pigs was slow, its fattening performance was improved obviously by crossbreeding with Duroc boar and Berkshire boar. Using growth curve fitting with the regression analysis could estimate the marketing time and spinodal weight, the pure black pig was 71.6 kg and 193.4 days, Duroc hybridization F1 was 90.3 kg and 200.4 days, Berkshire hybridization F1 was 89.7 kg and 198.6 days.

  14. Effects of norfloxacin on hepatic genes expression of P450 isoforms (CYP1A and CYP3A), GST and P-glycoprotein (P-gp) in Swordtail fish (Xiphophorus Helleri).

    Science.gov (United States)

    Liang, Ximei; Wang, Lan; Ou, Ruikang; Nie, Xiangping; Yang, YuFeng; Wang, Fang; Li, Kaibin

    2015-10-01

    The presence of antibiotics including norfloxacin in the aquatic environment may cause adverse effects in non-target organisms. But the toxic mechanisms of fluoroquinolone to fish species are still not completely elucidated. Thus, it is essential to investigate the response of fish to the exposure of fluoroquinolone at molecular or cellular level for better and earlier prediction of these environmental pollutants toxicity. The sub-chronic toxic effects of norfloxacin (NOR) on swordtail fish (Xiphophoru s helleri) were investigated by measuring mRNA expression of cytochrome P450 1A (CYP1A), cytochrome P450 3A (CYP3A), glutathione S-transferase (GST) and P-glycoprotein (P-gp) and their corresponding enzyme activities (including ethoxyresorufin O-deethylase, erythromycin N-demethylase and GST. Results showed that NOR significantly affected the expression of CYP1A, CYP3A, GST and P-gp genes in swordtails. The gene expressions were more responsive to NOR exposure than their corresponding enzyme activities. Moreover, sexual differences were found in gene expression and enzyme activities of swordtails exposed to NOR. Females displayed more dramatic changes than males. The study further demonstrated that the combined biochemical and molecular parameters were considered as useful biomarkers to improve our understanding of potential ecotoxicological risks of NOR exposure to aquatic organisms.

  15. Species hybridization in the genus Pinus

    Science.gov (United States)

    Peter W. Garrett

    1979-01-01

    Results of a breeding program in which a large number of pine species were tested indicate that a number of species and hybrids may be useful in the northeastern United States. Austrian black pine x Japanese black pine and hybrids containing Japanese red pine all had good growth rates. While none of the soft pines grew faster than eastern white pine, a number of...

  16. Padrões de miniestacas e sazonalidade na produção de mudas clonais de Eucalyptus grandis Hill X E. urophylla S. T. Black Patterns of mini-cuttings and seasonality in seedlings production Eucalyptus grandis Hill X E. urophylla Hybrid S. T. Black

    Directory of Open Access Journals (Sweden)

    Cibele Chaves Souza

    2013-02-01

    Full Text Available Este estudo teve por objetivo avaliar a influência de diferentes padrões de miniestacas no enraizamento e produção de mudas do híbrido do Eucalyptus grandis Hill x E. urophylla S.T. Black no verão e no inverno. Experimentos com cinco clones e 12 diferentes padrões de miniestacas foram conduzidos em duas épocas do ano (verão e inverno. A sobrevivência e enraizamento das miniestacas foram avaliados na saída da casa de vegetação e na saída da casa de sombra e, a pleno sol, a sobrevivência, a altura, o diâmetro do colo, o peso de massa seca da parte aérea e o da raiz. Os resultados indicaram que a manutenção das folhas é importante para o enraizamento de miniestacas de Eucalyptus grandis x E. urophylla, e as folhas basais obtiveram maiores valores de enraizamento. Mudas produzidas no verão, utilizando miniestacas de 10 cm de tamanho, tiveram maior crescimento. A metodologia de não redução das folhas mostrou-se procedimento adequado para produção de mudas nas duas épocas do ano.The present study aimed to evaluate the influence of different patterns of mini-cuttigs on rooting and production of hybrid Eucalyptus grandis Hill x E. urophylla S. T. Black hybrid in summer and winter. Experiments with five clones and 12 different patterns of mini-cuttings were conducted in two seasons (summer and winter. The survival and rooting were evaluated ate the output greenhouse and output of the shade and in full sun, survival, height, diameter, the dry weight of shoot and root. The results indicated that the maintenance of leaves is important for rooting mini-cuttings of Eucalyptus grandis Hill x E. urophylla S. T. Black hybrids, and the basal leaves had higher values of rooting. Seedlings produced in summer, using cuttings of 10 cm in size, had higher growth's methodology leaves no reduction procedure proved suitable for seedling production in both seasons.

  17. The Effect Siliceous Earth/Carbon Black Hybrid Filler on Properties of Natural Rubber%硅土/炭黑复合填料对天然橡胶性能的影响

    Institute of Scientific and Technical Information of China (English)

    汪晓敏; 陈静; 钟杰平; 许逵; 潘荣楷; 高利军

    2016-01-01

    对硅土进行活化和改性处理,通过测定吸油值、吸碘值进行表征。将经改性处理的硅土与炭黑复合用于填充天然橡胶,进行物理机械性能测试。结果表明:硅土与炭黑并用,与单独填充炭黑相比,对橡胶的加工性能影响不明显。拉伸性能测试结果表明,复合填料与单独填充炭黑相比,能提高NR硫化胶拉伸强度,扯断伸长率提高。当硅土与炭黑质量比为2∶5时,NR硫化胶的拉伸强度达到最大。硅土和炭黑并用能增强天然橡胶的综合性能,降低成本。%Siliceous earth from Fujian was selected as raw material. The composition and structure were analyzed. Siliceous earth was modified by KH570 and characterized by iodine absorption number and DBP. The modiifed siliceous earth was blended with silica to ifll natural rubber (NR). Curing characteristics, mechanical properties of NR composites were analyzed. The results show that when carbon black and siliceous earth work together, the inlfuence on the processing performance of NR isn’t obvious. Tensile test results show that the hybrid ifller compared with carbon black used alone, can improve the tensile strength of NR composites, and signiifcantly increase the rubber elasticity. When the mass ratio of siliceous earth to carbon black is2∶5, the tensile strenth of NR composites is the best. Siliceous earth and carbon black using together can inhance the comprehensive properties of NR and reduce the cost.

  18. Black Droplets

    CERN Document Server

    Santos, Jorge E

    2014-01-01

    Black droplets and black funnels are gravitational duals to states of a large N, strongly coupled CFT on a fixed black hole background. We numerically construct black droplets corresponding to a CFT on a Schwarzchild background with finite asymptotic temperature. We find two branches of such droplet solutions which meet at a turning point. Our results suggest that the equilibrium black droplet solution does not exist, which would imply that the Hartle-Hawking state in this system is dual to the black funnel constructed in \\cite{Santos:2012he}. We also compute the holographic stress energy tensor and match its asymptotic behaviour to perturbation theory.

  19. Black psyllium

    Science.gov (United States)

    Black psyllium is a weed that grows aggressively throughout the world. The plant was spread with the ... to make medicine. Be careful not to confuse black psyllium with other forms of psyllium including blond ...

  20. The genome of black raspberry (Rubus occidentalis)

    Science.gov (United States)

    Black raspberry (Rubus occidentalis) is an important specialty fruit crop in the U.S. Pacific Northwest that can hybridize with the globally commercialized red raspberry (R. idaeus). Here we report a 243 Mb draft genome of black raspberry that will serve as a useful reference for the Rosaceae and Ru...

  1. Acute toxicity of benzene, chlorobenzene, phenol, p-chlorophenol on zebrafish,guppy and Xiphophorus helleri%苯、氯苯、苯酚、4-氯酚对斑马鱼、孔雀鱼、剑尾鱼的急性毒性

    Institute of Scientific and Technical Information of China (English)

    邢军

    2011-01-01

    In the research, zebrafish, guppy, and Xiphophorus helleri were used as test fishes to study the acute toxicity of four highly toxic substances benzene, chlorobenzene, phenol, and p-chlorophenol on them through semi static toxicity test. The results indicated that 96 h LC50 of the above chemicals toward zebrafish were 132.22, 28.86, 9.66, and 4.29 mg/L, toward Xiphophorus helleri were 123.76, 27.25, 8.86, 4.29 mg/L, and toward guppy were 131.25, 7.88, 9.33, 4.59 mg/L respectively. The toxicity sequence for the studied chemicals is benzenehelleri were more sensitive to these pollutants, and the result with guppy and Xiphophorus helleri had better reproducibility, so guppy and Xiphophorus helleri are good laboratory fishes for acute toxicity test.%以斑马鱼(Zebra fish)Danio rerio、剑尾鱼Xiphophorus hellerii、孔雀鱼(Guppy)Poecilia reticulata为受试鱼种,采用半静态试验,考察苯、苯酚、氯苯、4-氯苯酚对3种鱼的急性毒性,结果表明,上述4种有机物对斑马鱼的96 h LC50分别为132.22、28.86、9.66、4.29 mg·L-1;对剑尾鱼的96 h LC50分别为123.76、27.25、8.86、4.29 mg·L-1;对孔雀鱼的96 h LC50分别为131.25、27.88、9.33、4.59 mg·L-1,都属于高毒物质.毒性大小为苯<苯酚<氯苯<4-氯苯酚.毒性大小与取代基的类型有关,-Cl的毒性要大于-OH,-Cl和-OH的联合毒性大于单独的-Cl和-OH.孔雀鱼和剑尾鱼对上述有机污染物具有较好的敏感性,结果稳定,重现性好,可以作为急性毒性试验的受试鱼种.

  2. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  3. Influence on longevity of blueberry, cinnamon, green and black tea, pomegranate, sesame, curcumin, morin, pycnogenol, quercetin, and taxifolin fed iso-calorically to long-lived, F1 hybrid mice.

    Science.gov (United States)

    Spindler, Stephen R; Mote, Patricia L; Flegal, James M; Teter, Bruce

    2013-04-01

    Phytonutrients reportedly extend the life span of Caenorhabditis elegans, Drosophila, and mice. We tested extracts of blueberry, pomegranate, green and black tea, cinnamon, sesame, and French maritime pine bark (Pycnogenol and taxifolin), as well as curcumin, morin, and quercetin for their effects on the life span of mice. While many of these phytonutrients reportedly extend the life span of model organisms, we found no significant effect on the life span of male F1 hybrid mice, even though the dosages used reportedly produce defined therapeutic end points in mice. The compounds were fed beginning at 12 months of age. The control and treatment groups were iso-caloric with respect to one another. A 40% calorically restricted and other groups not reported here did experience life span extension. Body weights were un-changed relative to controls for all but two supplemented groups, indicating most supplements did not change energy absorption or utilization. Tea extracts with morin decreased weight, whereas quercetin, taxifolin, and Pycnogenol together increased weight. These changes may be due to altered locomotion or fatty acid biosynthesis. Published reports of murine life span extension using curcumin or tea components may have resulted from induced caloric restriction. Together, our results do not support the idea that isolated phytonutrient anti-oxidants and anti-inflammatories are potential longevity therapeutics, even though consumption of whole fruits and vegetables is associated with enhanced health span and life span.

  4. A novel MC1R allele for black coat colour reveals the Polynesian ancestry and hybridization patterns of Hawaiian feral pigs

    Science.gov (United States)

    Linderholm, Anna; Spencer, Daisy; Battista, Vincent; Frantz, Laurent; Barnett, Ross; Fleischer, Robert C.; James, Helen F.; Duffy, Dave; Sparks, Jed P.; Clements, David R.; Andersson, Leif; Dobney, Keith; Leonard, Jennifer A.

    2016-01-01

    Pigs (Sus scrofa) have played an important cultural role in Hawaii since Polynesians first introduced them in approximately AD 1200. Additional varieties of pigs were introduced following Captain Cook's arrival in Hawaii in 1778 and it has been suggested that the current pig population may descend primarily, or even exclusively, from European pigs. Although populations of feral pigs today are an important source of recreational hunting on all of the major islands, they also negatively impact native plants and animals. As a result, understanding the origins of these feral pig populations has significant ramifications for discussions concerning conservation management, identity and cultural continuity on the islands. Here, we analysed a neutral mitochondrial marker and a functional nuclear coat colour marker in 57 feral Hawaiian pigs. Through the identification of a new mutation in the MC1R gene that results in black coloration, we demonstrate that Hawaiian feral pigs are mostly the descendants of those originally introduced during Polynesian settlement, though there is evidence for some admixture. As such, extant Hawaiian pigs represent a unique historical lineage that is not exclusively descended from feral pigs of European origin. PMID:27703696

  5. Investigation of isomeric flavanol structures in black tea thearubigins using ultraperformance liquid chromatography coupled to hybrid quadrupole/ion mobility/time of flight mass spectrometry.

    Science.gov (United States)

    Yassin, Ghada H; Grun, Christian; Koek, Jean H; Assaf, Khaleel I; Kuhnert, Nikolai

    2014-11-01

    Ultra performance liquid chromatography (UPLC) when coupled to ion mobility (IMS)/orthogonal acceleration time of flight mass spectrometry is a suitable technique for analyzing complex mixtures such as the black tea thearubigins. With the aid of this advanced instrumental analysis, we were able to separate and identify different isomeric components in the complex mixture which could previously not be differentiated by a conventional high performance liquid chromatography/tandem mass spectrometry. In this study, the difference between isomeric structures theasinensins, proanthocyanidins B-type and rutin (quercetin-3O-rutinoside) were studied, and these are present abundantly in many botanical sources. The differentiation between these structures was accomplished according to their acquired mobility drift times differing from the traditional investigations in mass spectrometry, where calculation of theoretical collisional cross sections allowed assignment of the individual isomeric structures. The present work demonstrates UPLC-IMS-MS as an efficient technology for isolating and separating isobaric and isomeric structures existing in complex mixtures discriminating between them according to their characteristic fragment ions and mobility drift times. Therefore, a rational assignment of isomeric structures in many phenolic secondary metabolites based on the ion mobility data might be useful in mass spectrometry-based structure analysis in the future.

  6. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.

  7. Black tea

    Science.gov (United States)

    ... combination.Talk with your health provider.Birth control pills (Contraceptive drugs)Black tea contains caffeine. The body breaks down caffeine to get rid of it. Birth control pills can decrease how quickly the body breaks down ...

  8. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  9. Black holes

    CERN Document Server

    Chrúsciel, P T

    2002-01-01

    This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usual one for gravity, and leads to the one associated with the Unruh metric in the case of Euler equations. We review the global conditions which have been used in the Scri-based definition of a black hole and point out the deficiencies of the Scri approach. Various results on the structure of horizons and apparent horizons are presented, and a new proof of semi-convexity of horizons based on a variational principle is given. Recent results on the classification of stationary singularity-free vacuum solutions are reviewed. ...

  10. 花椰菜——黑芥体细胞杂交获得抗黑腐病异附加系新材料%New Alien Additon Lines Resistance to Black Rot Generated by Somatic Hybridization Between Cauliflower and Black Mustard

    Institute of Scientific and Technical Information of China (English)

    王桂香; 严红; 曾兴莹; 盛小光; 唐宇; 韩硕; 宗梅; 陆坤; 刘凡

    2011-01-01

    In this study, the asymmetrical somatic hybrids of cauliflower and Brassica nigra and their selfed or backcrossed progenies were analysed using morphological, cytological and molecular methods. Fifty advanced selfing or backcrossing descendants were obtained. Besides 30 lines with an intermediate morphology to that of the parents, there were 20 lines with a nuclear DNA content below 2.24 pg · cell-1 and chromosomes number less than 28 displaying the cauliflower-like morphology. Combining with successive black rot resistance assay, a set of alien additon lines were obtained, in which 12 lines with high resistance, 17 lines being resistant, those accounted for 14% of the total materials tested. Three plants (PFCN29 BC3-3-5, PFCNI6-1 S2BC3-107 and PFCN14-1 S1BC4-123) displayed a more cauliflower-like morphology and high resistance to Xcc strain CH15 were confirmed to have a total set of cauliflower chromosomes added with 2, 7 and 8 B. nigra-derived chromosomes respectively by genomic in situ hybridization (GISH) .%以花椰菜——黑芥体细胞杂种的自交及回交后代为材料,建立了结合抗病性人工接种鉴定,流式细胞仪DNA含量分析,B基因组特异分子标记和染色体原位杂交的大规模群体分析技术,在50份高代自交及回交材料中筛选获得了20份形态学特征偏向花椰菜,30份呈花椰菜一黑芥中间类型的材料。细胞DNA含量检测(FLC)及染色体计数结果表明,偏花椰菜的类型,DNA含量基本在2.24Pg·cell^-1以下,染色体数在28条以下。经连续3年黑腐病病菌人工接种鉴定,获得高抗株系12个,抗性株系17个,占全部受试材料的14%。对其中3个(PFCN29BC3-3-5、PFCNl6-1S2BC3-107和PFCNl4-1S1BC4—123)形态偏花椰菜且高抗黑腐病的植株进行基因组原位杂交,结果显示其分别为花椰菜染色体组附加了2、7和8条黑芥染色体的异附加系材料。这些植株可以用于后续的研究和

  11. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  12. black cat

    Institute of Scientific and Technical Information of China (English)

    杜铁梅

    2016-01-01

    The black cat is a masterpiece of short fiction of Poe. He successfully solved the problem of creating of the horror effect by using scene description, symbol, repetition and first-person narrative methods. And created a complete and unified mysterious terror, achieved the effect of shocking. This paper aims to discuss the mystery in-depth and to enrich the research system in Poe’s novels.

  13. The genome of black raspberry (Rubus occidentalis).

    Science.gov (United States)

    VanBuren, Robert; Bryant, Doug; Bushakra, Jill M; Vining, Kelly J; Edger, Patrick P; Rowley, Erik R; Priest, Henry D; Michael, Todd P; Lyons, Eric; Filichkin, Sergei A; Dossett, Michael; Finn, Chad E; Bassil, Nahla V; Mockler, Todd C

    2016-09-01

    Black raspberry (Rubus occidentalis) is an important specialty fruit crop in the US Pacific Northwest that can hybridize with the globally commercialized red raspberry (R. idaeus). Here we report a 243 Mb draft genome of black raspberry that will serve as a useful reference for the Rosaceae and Rubus fruit crops (raspberry, blackberry, and their hybrids). The black raspberry genome is largely collinear to the diploid woodland strawberry (Fragaria vesca) with a conserved karyotype and few notable structural rearrangements. Centromeric satellite repeats are widely dispersed across the black raspberry genome, in contrast to the tight association with the centromere observed in most plants. Among the 28 005 predicted protein-coding genes, we identified 290 very recent small-scale gene duplicates enriched for sugar metabolism, fruit development, and anthocyanin related genes which may be related to key agronomic traits during black raspberry domestication. This contrasts patterns of recent duplications in the wild woodland strawberry F. vesca, which show no patterns of enrichment, suggesting gene duplications contributed to domestication traits. Expression profiles from a fruit ripening series and roots exposed to Verticillium dahliae shed insight into fruit development and disease response, respectively. The resources presented here will expedite the development of improved black and red raspberry, blackberry and other Rubus cultivars.

  14. Black gold

    CERN Document Server

    Fletcher, MW

    2016-01-01

    Following the Yom Kippur war of October 1973, OPEC raises the price of oil by 70% along with a 5% reduction in oil production. Len Saunders a highly skilled and knowledgeable British engineer for Jaguar motors, is approached by the UK energy commission in the January of 1974 to create a new propulsion system; using a secret document from a German WW2 scientist, that they have come into possession of. Len Saunders sets to work on creating the holy grail of energy. Seven years later 1981, Haidar Farooq the Kuwait oil minister working at OPEC and head of a secret organisation named Black Gold bec

  15. Primordial Black Holes from First Principles (Overview)

    Science.gov (United States)

    Lam, Casey; Bloomfield, Jolyon; Moss, Zander; Russell, Megan; Face, Stephen; Guth, Alan

    2017-01-01

    Given a power spectrum from inflation, our goal is to calculate, from first principles, the number density and mass spectrum of primordial black holes that form in the early universe. Previously, these have been calculated using the Press- Schechter formalism and some demonstrably dubious rules of thumb regarding predictions of black hole collapse. Instead, we use Monte Carlo integration methods to sample field configurations from a power spectrum combined with numerical relativity simulations to obtain a more accurate picture of primordial black hole formation. We demonstrate how this can be applied for both Gaussian perturbations and the more interesting (for primordial black holes) theory of hybrid inflation. One of the tools that we employ is a variant of the BBKS formalism for computing the statistics of density peaks in the early universe. We discuss the issue of overcounting due to subpeaks that can arise from this approach (the ``cloud-in-cloud'' problem). MIT UROP Office- Paul E. Gray (1954) Endowed Fund.

  16. Hybrid origin of Audubon's warbler.

    Science.gov (United States)

    Brelsford, Alan; Milá, Borja; Irwin, Darren E

    2011-06-01

    Several animal species have recently been shown to have hybrid origins, but no avian examples have been documented with molecular evidence. We investigate whether the Audubon's warbler (Dendroica auduboni), one of four visually distinct species in the yellow-rumped warbler complex, has originated through hybridization between two other species in this group, the myrtle warbler (D. coronata) and black-fronted warbler (D. nigrifrons). Analysis of nuclear amplified fragment length polymorphism (AFLP) and sequence markers shows that Audubon's warblers are genetically intermediate and carry a mixture of alleles otherwise found only in one or the other of their putative parental species. Audubon's warblers also carry two deeply divergent mitochondrial DNA lineages, each shared with only one putative parental form. Broad clines between Audubon's and black-fronted warblers in AFLP markers call into question the validity of these two forms as full species; nevertheless, our results suggest that the Audubon's warbler probably originated through hybridization between two long-diverged species. It is likely that more cases of avian species of hybrid origin will be revealed by surveys of variation in nuclear DNA and other traits. © 2011 Blackwell Publishing Ltd.

  17. Black Urine

    Directory of Open Access Journals (Sweden)

    Rahim Vakili

    2016-06-01

    Full Text Available A 2-year-old boy was born at term of healthy, non-consanguineous Iranian parents. His mother attended in the clinic with the history of sometimes discoloration of diapers after passing urine. She noticed that first at the age of one month with intensified in recent months. His Physical examination and growth parameters were normal. His mother denied taking any medication (sorbitol, nitrofurantoin, metronidazole, methocarbamol, sena and methyldopa (5. Qualitative urine examination showed dark black discoloration. By this history, alkaptonuria was the most clinical suspicious. A 24-hour-urine sample was collected and sent for quantitative measurements. The urine sample was highly positive for homogentisic acid and negative for porphyrin metabolites.

  18. Dissonant Black Droplets and Black Funnels

    CERN Document Server

    Fischetti, Sebastian; Way, Benson

    2016-01-01

    A holographic field theory on a fixed black hole background has a gravitational dual represented by a black funnel or a black droplet. These states are "detuned" when the temperature of the field theory near the horizon does not match the temperature of the background black hole. In particular, the gravitational dual to the Boulware state must be a detuned solution. We construct detuned droplets and funnels dual to a Schwarzschild background and show that the Boulware phase is represented by a droplet. We also construct hairy black droplets associated to a low-temperature scalar condensation instability and show that they are thermodynamically preferred to their hairless counterparts.

  19. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  20. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...

  1. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  2. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  3. Highly eccentric inspirals into a black hole

    Science.gov (United States)

    Osburn, Thomas; Warburton, Niels; Evans, Charles R.

    2016-03-01

    We model the inspiral of a compact stellar-mass object into a massive nonrotating black hole including all dissipative and conservative first-order-in-the-mass-ratio effects on the orbital motion. The techniques we develop allow inspirals with initial eccentricities as high as e ˜0.8 and initial separations as large as p ˜50 to be evolved through many thousands of orbits up to the onset of the plunge into the black hole. The inspiral is computed using an osculating elements scheme driven by a hybridized self-force model, which combines Lorenz-gauge self-force results with highly accurate flux data from a Regge-Wheeler-Zerilli code. The high accuracy of our hybrid self-force model allows the orbital phase of the inspirals to be tracked to within ˜0.1 radians or better. The difference between self-force models and inspirals computed in the radiative approximation is quantified.

  4. Hybrid Natural Inflation

    Science.gov (United States)

    Ross, Graham G.; Germán, Gabriel; Vázquez, J. Alberto

    2016-05-01

    We construct two simple effective field theory versions of Hybrid Natural Inflation (HNI) that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, V = Δ4(1 + acos( ϕ/f)), arises naturally, with the inflaton field a pseudo-Nambu-Goldstone boson. The end of inflation is triggered by a waterfall field and the conditions for this to happen are determined. Also of interest is the fact that the slow-roll parameter ɛ (and hence the tensor r) is a non-monotonic function of the field with a maximum where observables take universal values that determines the maximum possible tensor to scalar ratio r. In one of the models the inflationary scale can be as low as the electroweak scale. We explore in detail the associated HNI phenomenology, taking account of the constraints from Black Hole production, and perform a detailed fit to the Planck 2015 temperature and polarisation data.

  5. The Black Black Woman and the Black Middle Class.

    Science.gov (United States)

    Jeffers, Trellie

    1981-01-01

    Reprint of a 1973 article that describes the discrimination that particularly dark-skinned Black women suffer, especially at the hands of a color-conscious Black middle class. Calls for dark women to look to the African appearance and working-class roots as sources of pride and strength. (GC)

  6. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average reflecta......We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....

  7. Higher spin black holes

    National Research Council Canada - National Science Library

    Gutperle, Michael; Kraus, Per

    2011-01-01

    .... We find solutions that generalize the BTZ black hole and carry spin-3 charge. The black hole entropy formula yields a result for the asymptotic growth of the partition function at finite spin-3 chemical potential...

  8. Black widow spider (image)

    Science.gov (United States)

    This is a black widow spider. Note the red "hour glass" on the abdomen. The bite of the black widow can produce severe symptoms but is seldom fatal, except in young children and older adults. (Image courtesy ...

  9. Black hole hair removal

    Science.gov (United States)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  10. Black Hole Hair Removal

    CERN Document Server

    Banerjee, Nabamita; Sen, Ashoke

    2009-01-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair, -- degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  11. Counseling Black Adolescent Parents

    Science.gov (United States)

    Gilbert, Gwendolyn C.

    1974-01-01

    Black adolescent parents need counsel from social workers who are able to intervene with a discerning knowledge of concepts, such as neocolonialism, survival, and liberation, that are important to them and to the black community. (Author)

  12. Empowering Rhetoric: Black Students Writing Black Panthers.

    Science.gov (United States)

    Pough, Gwendolyn D.

    2002-01-01

    Examines Black student responses to Black Panther Party documents and how those documents moved the students toward change. Maintains that by allowing the classroom to function as a public space which students can discuss the issues that matter to them, teachers can help to foster and encourage student activism and ultimately their empowerment.…

  13. Charged Lifshitz Black Holes

    OpenAIRE

    Dehghani, M. H.; Pourhasan, R.; Mann, R. B.

    2011-01-01

    We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary $z$ and any topology. We find that the behaviour of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical pot...

  14. Life inside black holes

    CERN Document Server

    Dokuchaev, V I

    2012-01-01

    We consider test planet and photon orbits of the third kind inside a black hole, which are stable, periodic and neither come out of the black hole nor terminate at the singularity. Interiors of supermassive black holes may be inhabited by advanced civilizations living on planets with the third-kind orbits. In principle, one can get information from the interiors of black holes by observing their white hole counterparts.

  15. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  16. Black Hole Thermodynamics

    Science.gov (United States)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  17. Agronomic Performance of Two Tetraploid Hybrid Plantains in Ghana

    OpenAIRE

    Beloved Mensah Dzomeku; Asieduwa Agnes Ankomah; Solomon Kodjo Darkey

    2009-01-01

    Field performance of two IITA plantain hybrids (‘PITA-1’, ‘PITA-4’) were assessed at two locations in Ghana alongside two local landraces (False Horn ‘Brodeyuo’, Intermediate French ‘Oniaba’) and a hybrid cultivar ‘Apem Hemaa’ (‘FHIA-21’). The objective of the study was to identify high yielding and disease resistant hybrids for growers in Ghana. The hybrids were evaluated for their agronomic performance and yield, tolerance to Black Sigatoka disease, number of functional leaves at flowering ...

  18. Monopole black hole skyrmions

    OpenAIRE

    Moss, I. G.; Shiiki, N.; Winstanley, E.

    2000-01-01

    Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

  19. Marketing for Black Alums.

    Science.gov (United States)

    Harris, Tracy A.

    1994-01-01

    Considers need for colleges and universities to develop effective marketing plan for recruitment of black students. Highlights advantages of designing marketing plan for recruitment of black alumni to assist in recruitment and retention of black students. Identifies key indicators that often hinder institutions in their recruitment of black…

  20. Monopole Black Hole Skyrmions

    OpenAIRE

    Moss, I. G.; Shiiki, N.; Winstanley, E.

    2000-01-01

    Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

  1. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  2. Hybrid neural network models of transducers

    Science.gov (United States)

    Xie, Shilin; Zhang, Xinong; Chen, Shenglai; Zhu, Changchun

    2011-10-01

    A hybrid neural network (NN) approach is proposed and applied to modeling of transducers in the paper. The modeling procedures are also presented in detail. First, the simulated studies on the modeling of single input-single output and multi input-multi output transducers are conducted respectively by use of the developed hybrid NN scheme. Secondly, the hybrid NN modeling approach is utilized to characterize a six-axis force sensor prototype based on the measured data. The results show that the hybrid NN approach can significantly improve modeling precision in comparison with the conventional modeling method. In addition, the method is superior to NN black-box modeling because the former possesses smaller network scale, higher convergence speed, higher model precision and better generalization performance.

  3. Vitellogenin of swordtail fish Xiphophorus helleri:cloning, expression and an assay development%剑尾鱼卵黄蛋白原基因片段克隆、表达及蛋白检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    刘春; 李凯彬; 王芳; 聂湘平; 吴淑勤

    2007-01-01

    本研究通过对剑尾鱼(Xiphophorus helleri)卵黄蛋白原基因片段的克隆和表达,建立了剑尾鱼卵黄蛋白原蛋白检测方法.根据已发表的底鳉(Fundulus heteroclitus)卵黄蛋白原mRNA序列设计引物,利用RT-PCR法扩增出1段1 118 bp的剑尾鱼卵黄蛋白原cDNA片段,序列分析表明该片段与其他鱼类卵黄蛋白原基因序列相似性较高,其中与底鳉和食蚊鱼(Gambusia affinis)的同源性分别达87.4%和96.7%.在对该片段所编码氨基酸序列可能抗原位点分析的基础上,进行PCR改造构建原核表达载体,预期得到258个氨基酸的表达蛋白.表达载体转入大肠杆菌DH5α,经热诱导后,SDS-PAGE分析有29 kD的表达蛋白产生,与预期相符.以重组蛋白免疫新西兰大白兔,获得抗血清.雌激素(β-雌二醇)对剑尾鱼诱导后,用重组蛋白抗血清作一抗,进行Westernblot分析.结果表明,该抗血清能与剑尾鱼卵黄蛋白原特异结合,可应用于剑尾鱼卵黄蛋白原的检测.卵黄蛋白原是环境雌激素研究中较为特异、灵敏的生物标志物,剑尾鱼卵黄蛋白原检测方法的建立,为剑尾鱼环境监测应用提供良好基础.

  4. Agronomic Performance of Two Tetraploid Hybrid Plantains in Ghana

    Directory of Open Access Journals (Sweden)

    Beloved Mensah Dzomeku

    2009-12-01

    Full Text Available Field performance of two IITA plantain hybrids (‘PITA-1’, ‘PITA-4’ were assessed at two locations in Ghana alongside two local landraces (False Horn ‘Brodeyuo’, Intermediate French ‘Oniaba’ and a hybrid cultivar ‘Apem Hemaa’ (‘FHIA-21’. The objective of the study was to identify high yielding and disease resistant hybrids for growers in Ghana. The hybrids were evaluated for their agronomic performance and yield, tolerance to Black Sigatoka disease, number of functional leaves at flowering and at harvest, crop cycle, plant height and pseudostem girth. The results showed that the hybrids were tolerant/resistant to the Black Sigatoka (Mycosphaerella fi jiensis disease with high number of functional leaves at flowering and at harvest. This characteristic of the hybrids was an important feature that could fit well into the smallholder cropping system. The crop cycles were comparable to that of ‘False Horn’ plantains. The yield performance of the hybrids was better compared to the landraces. The number of hands per bunch produced by the hybrids was also higher than those of the landraces except the intermediate French plantain (‘Oniaba’. The finger lengths of the IITA hybrids were however shorter compared to the landraces and this could hinder their acceptance by consumers.

  5. On Accelerated Black Holes

    CERN Document Server

    Letelier, P S; Letelier, Patricio S.; Oliveira, Samuel R.

    1998-01-01

    The C-metric is revisited and global interpretation of some associated spacetimes are studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that the spacetime fo an accelerated Schwarzschild black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon. By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature. We also show that the usual upper bound on the product of the mass and acceleration parameters (<1/sqrt(27)) is just a coordinate artifact. The main results are extended to accelerated Kerr black holes. We found that they are not changed by the black hole rotation.

  6. Hybrid microelectronic technology

    Science.gov (United States)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  7. 转青鱼生长激素基因异源四倍体鲫鲤%Black Carp GH Gene Transgenic Allotetraploid Hybrids of Carassius auratus red var.(♀) × Cyprinus carpio (♂)

    Institute of Scientific and Technical Information of China (English)

    冯浩; 傅永明; 骆剑; 吴慧; 刘筠; 刘少军

    2011-01-01

    The ecological risk is the “bottleneck” for commercialization of transgenic fish. The sterile transgenic triploid fish derived from hydrating the transgenic tetraploid fish and transgenic diploid fish is one of the keys to solve this problem.The “all fish” gene construct (pbcAbcGHc) containing Black Carp B-actin gene promoter and cDNA of growth hormone (GH) gene from the same species was introduced into the fertilized eggs of the allotetroploid fish through microinjection. The contrast cultivation results show that the weight and body length of PO of the transgenic allotetraploid fish of 150 days were much larger than those of the controls. PCR assay was applied among 60 transgenic allotetraploid fish of 150 days and the integration ratio of the exogenous transplant gene in the genome of the caudal fin is 90%. The transplant gene could be detected in 13 of 20 samples from the sperm of the male transgenic tetraploid fish.The RT-PCR result demonstrates that the transcription of exogenous GH gene could be found in the muscle, liver,kidney and oval of the biggest transgenic allotetraploid fish. This study has developed PO of the Black Carp GH gene transgenic tetraploid fish with outstanding growth rate, which made the solid foundation for the pure line establishment of the transgenic tetraploid fish and for developing the sterile transgenic triploid fish.%生态安全性是转基因鱼走向市场的瓶颈,通过转基因四倍体鱼同转基因二倍体鱼杂交获得不育的转基因三倍体鱼是解决该问题的有效途径之一.本研究构建了青鱼β-actin基因启动子和青鱼生长激素(GH)基因精确连接的"金鱼"基因pbcAbcGHc;并采用显微注射法将pbcAbcGHc 导入异源四倍体鲫鲤受精卵.对照养殖结果表明,150日龄的转基因异源四倍体鲫鲤原代(P0)的体重及体长明显大于对照组.选择60尾P0代转基因异源四倍体鲫鲤,采用PCR方法检测出外源青鱼GH基因在P0代转基因四倍体尾

  8. Nanohybrid TiO2/carbon black sensor for NO2 gas

    Institute of Scientific and Technical Information of China (English)

    Wei-Jen Liou; Hong-Ming Lin

    2007-01-01

    A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol-gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.

  9. Is black coat color in wolves of Iran an evidence of admixed ancestry with dogs?

    Science.gov (United States)

    Khosravi, Rasoul; Asadi Aghbolaghi, Marzieh; Rezaei, Hamid Reza; Nourani, Elham; Kaboli, Mohammad

    2015-02-01

    Melanism is not considered a typical characteristic in wolves of Iran and dark wolves are believed to have originated from crossbreeding with dogs. Such hybrid individuals can be identified with the combined use of genetic and morphological markers. We analyzed two black wolves using a 544 base pairs (bp) fragment of the mtDNA control region and 15 microsatellite loci in comparison with 28 dogs, 28 wolves, and four known hybrids. The artificial neural networks (ANNs) method was applied to microsatellite data to separate genetically differentiated samples of wolves, dogs, and hybrids, and to determine the correct class for the black specimens. Individual assignments based on ANNs showed that black samples were genetically closer to wolves. Also, in the neighbor-joining network of mtDNA haplotypes, wolves and dogs were separated, with the dark specimens located in the wolf branch as two separate haplotypes. Furthermore, we compared 20 craniometrical characters of the two black individuals with 14 other wolves. The results showed that craniometrical measures of the two black wolves fall within the range of wolf skulls. We found no trace of recent hybridization with free-ranging dogs in the two black wolves. Dark coat color might be the result of a natural combination of alleles in the coat-color-determining gene, mutation in the K locus due to past hybridization with free-ranging dogs, or the effect of ecological factors and adaption to habitat conditions.

  10. Effect of Crossbreed on the Muscle Quality (Chemical Composition) in Yun-Ling Black Goats

    Institute of Scientific and Technical Information of China (English)

    JIA Jun-jing; TIAN Yun-bo; ZHANG Xi; HUANG Qi-chao; WEN Sheng-ping; GU Feng-ying; GE Chang-rong; CAO Zhen-hui; CHENG Zhi-bin; M. Jois

    2009-01-01

    Twenty castrated male goats, each of Yun-Ling Black goats (YLB goat), N×YLB hybrid goats (Nubian ♂×Yun-Ling Black goats ♀) and B×YLB hybrid goats (Boer ♂×Yun-Ling Black goats ♀), were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi (LD) and biceps femoris (BF) muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content (P0.05). The YLB goats had significantly higher (P0.05). In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower (P<0.05) than that in the hybrid goats.

  11. Marine genetic swamping: hybrids replace an obligately estuarine fish.

    Science.gov (United States)

    Roberts, David G; Gray, Charles A; West, Ronald J; Ayre, David J

    2010-02-01

    Populations of obligately estuarine taxa are potentially small and isolated and may lack genetic variation and display regional differentiation as a result of drift and inbreeding. Hybridization with a wide-ranging marine congener should introduce genetic variation and reduce the effects of inbreeding depression and genetic drift. However, high levels of hybridization can cause demographic and genetic swamping. In southeastern Australia hybridization occurs between obligately estuarine Black bream (Acanthopagrus butcheri) and migratory marine Yellowfin bream (Acanthopagrus australis). Here, we surveyed genetic variation at eight microsatellite loci and the mitochondrial control region of juvenile fish from five coastal lagoons (including temporal replication in two lagoons) (total n = 970) to determine the frequency and persistence of hybridization, and its likely consequence for the estuarine restricted A. butcheri. Of 688 juvenile fish genotyped 95% were either A. australis (347) or hybrids (309); only 5% (32) were A. butcheri. Most hybrids were later generation hybrids or A. butcheri backcrosses, which are likely multi-generational residents within lagoons. Far greater proportions of hybrid juveniles were found within two lagoons that are generally closed to the ocean (>90% hybrid fish within generally closed lagoons vs. 12-27% in permanently or intermittently open lagoons). In both lagoons, this was consistent across multiple cohorts of fish [79-97% hybrid fish (n = 282)]. Hybridization and introgression represent a major threat to the persistence of A. butcheri and have yet to be investigated for large numbers of estuarine taxa.

  12. Braneworld Black Holes

    CERN Document Server

    Whisker, Richard

    2008-01-01

    In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experimental tests of gravity. We then move on to a discussion of static, spherically symmetric braneworld black hole solutions. Assuming an equation of state for the ``Weyl term'', which encodes the effects of the extra dimension, we are able to classify the general behaviour of these solutions. We then use the strong field limit approach to investigate the gravitational lensing properties of some candidate braneworld black hole solutions. It is found that braneworld black holes could have significantly different observational signatures to the Schwarzschild black hole of standard general relativity. Rotating braneworld black hole solutions are also discussed, an...

  13. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  14. Extremal Hairy Black Holes

    CERN Document Server

    Gonzalez, P A; Saavedra, Joel; Vasquez, Yerko

    2014-01-01

    We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and an U(1) electromagnetic field. Solving the coupled Einstein-Maxwell-scalar system we find exact hairy charged black hole solutions with the scalar field regular everywhere. We go to the zero temperature limit and we study the effect of the scalar field on the near horizon geometry of an extremal black hole. We find that except a critical value of the charge of the black hole there is also a critical value of the charge of the scalar field beyond of which the extremal black hole is destabilized. We study the thermodynamics of these solutions and we find that if the space is flat then at low temperature the Reissner-Nordstr\\"om black hole is thermodynamically preferred, while if the space is AdS the hairy charged black hole is thermodynamically preferred at low temperature.

  15. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  16. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...... masters», i.e. by producing skills for the labour market and enabling individuals to progress more or less directly to higher education. The specific focus of this book is placed on conditions, structures and processes which help to combine VET with qualifications leading into higher education...

  17. Perturbations around black holes

    CERN Document Server

    Wang, B

    2005-01-01

    Perturbations around black holes have been an intriguing topic in the last few decades. They are particularly important today, since they relate to the gravitational wave observations which may provide the unique fingerprint of black holes' existence. Besides the astrophysical interest, theoretically perturbations around black holes can be used as testing grounds to examine the proposed AdS/CFT and dS/CFT correspondence.

  18. Physics of black holes

    OpenAIRE

    Thorne, Kip S.

    1982-01-01

    The activity at the galactic center might be fuelled by energy release near a large black hole. In this talk I describe some relativistic effects which may be relevant to this process. I use Newtonian language so far as possible and illustrate the effects with simple  analogies. Specifically, I describe the gravitational field near a black hole, Lens‐Thirring and geodetic precession, electro‐magnetic energy extraction of the spin energy of a black hole and the structure of accretion tori arou...

  19. Black Branes as Piezoelectrics

    CERN Document Server

    Armas, Jay; Obers, Niels A

    2012-01-01

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  20. Black branes as piezoelectrics.

    Science.gov (United States)

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  1. Asymptotic black holes

    Science.gov (United States)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  2. Asymptotic Black Holes

    CERN Document Server

    Ho, Pei-Ming

    2016-01-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  3. Ten shades of black

    CERN Document Server

    Hod, Shahar

    2015-01-01

    The holographic principle has taught us that, as far as their entropy content is concerned, black holes in $(3+1)$-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat $(2+1)$-dimensional spacetimes. In this essay we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordstr\\"om black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine $(3+1)$-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the $(3+1)$-dimensional black holes effectively behave as p...

  4. Black Hole Thermodynamics

    CERN Document Server

    Carlip, S

    2014-01-01

    The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many independent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox.

  5. Rape and the prevalence of hybrids in broadly sympatric species: a case study using albatrosses

    Directory of Open Access Journals (Sweden)

    Sievert Rohwer

    2014-06-01

    Full Text Available Conspecific rape often increases male reproductive success. However, the haste and aggression of forced copulations suggests that males may sometimes rape heterospecific females, thus making rape a likely, but undocumented, source of hybrids between broadly sympatric species. We present evidence that heterospecific rape may be the source of hybrids between Black-footed and Laysan Albatrosses (Phoebastria nigripes, and P. immutabilis, respectively. Extensive field studies have shown that paired (but not unpaired males of both of these albatross species use rape as a supplemental reproductive strategy. Between species differences in size, timing of laying, and aggressiveness suggest that Black-footed Albatrosses should be more successful than Laysan Albatrosses in heteropspecific rape attempts, and male Black-footed Albatrosses have been observed attempting to force copulations on female Laysan Albatrosses. Nuclear markers showed that the six hybrids we studied were F1s and mitochondrial markers showed that male Black-footed Albatrosses sired all six hybrids. Long-term gene exchange between these species has been from Black-footed Albatrosses into Laysan Albatrosses, suggesting that the siring asymmetry found in our hybrids has long persisted. If hybrids are sired in heterospecific rapes, they presumably would be raised and sexually imprinted on Laysan Albatrosses, and two unmated hybrids in a previous study courted only Laysan Albatrosses.

  6. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  7. Continuity Controlled Hybrid Automata

    OpenAIRE

    Bergstra, J. A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of hybrid automata as timed transition systems. We also relate the synchronized product operator on hybrid automata to the parallel composition operator of the process algebra. It turns out that the f...

  8. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    Koustubh Ajit Kabe

    2012-09-01

    In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.

  9. Black holes matter

    DEFF Research Database (Denmark)

    Kragh, Helge Stjernholm

    2016-01-01

    Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

  10. Perturbing supersymmetric black hole

    CERN Document Server

    Onozawa, H; Mishima, T; Ishihara, H; Onozawa, Hisashi; Okamura, Takashi; Mishima, Takashi; Ishihara, Hideki

    1996-01-01

    An investigation of the perturbations of the Reissner-Nordstr\\"{o}m black hole in the N=2 supergravity is presented. In the extreme case, the black hole responds to the perturbation of each field in the same manner. This is possibly because we can match the modes of the graviton, gravitino, and photon using supersymmetry transformations.

  11. Black hole levitron

    NARCIS (Netherlands)

    Arsiwalla, X.D.; Verlinde, E.P.

    2010-01-01

    We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.’s multicenter

  12. Blacks and Trade Unionism

    Science.gov (United States)

    Ashenfelter, Orley

    1975-01-01

    This testimony, before a public hearing of the New York City Commission on Human Rights in May 1974, focuses on two issues: (1) the effect of the presence of trade unionism on the position of black workers in the labor market relative to white workers; and (2) the effect of federal government efforts to increase the position of black workers…

  13. Arbitrators, Blacks and Discipline

    Science.gov (United States)

    Jennings, Kenneth

    1975-01-01

    A discussion of the handling of disciplinary problems of black employees concludes that management should be concerned because of the effect that grievance resolution may have on the company's overall employee discipline program and the additional appeal alternatives available to the black employee. (Author/EA)

  14. Scattering by Black Holes

    CERN Document Server

    Andersson, N

    2000-01-01

    This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.

  15. Fifty shades of black

    Science.gov (United States)

    Cartwright, Jon

    2015-11-01

    Creating dark materials that prevent reflections has become hot competition recently, with Guinness World Records having to keep revising the darkest substance yet created. But depending on who's asking, the best black may not be the blackest black, as Jon Cartwright discovers.

  16. Hybridized tetraquarks

    Directory of Open Access Journals (Sweden)

    A. Esposito

    2016-07-01

    Full Text Available We propose a new interpretation of the neutral and charged X,Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X,Z particles. Considerations on a state with the same quantum numbers as the X(5568 are also made.

  17. Hybridized Tetraquarks

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero binding energy whose counterpart in h-tetraquarks is a positive quantity. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs pi+- channel by the D0 collaboration and the negative result presented subsequently by the LHCb collaboration are understood in this scheme, together with a considerable portion of available data on X, Z particles. Considerations on a state with the same quantum numbers as the X(5568) are also made.

  18. Lifshitz Topological Black Holes

    CERN Document Server

    Mann, R B

    2009-01-01

    I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

  19. Cosmological Black Holes

    CERN Document Server

    Stornaiolo, C

    2002-01-01

    In this letter we propose the existence of low density black holes and discuss its compatibility with the cosmological observations. The origin of these black holes can be traced back to the collapse of long wavelength cosmological perturbations during the matter dominated era, when the densities are low enough to neglect any internal and thermal pressure. By introducing a threshold density $\\hat{\\rho}$ above which pressure and non-gravitational interactions become effective, we find the highest wavelength for the perturbations that can reach an equilibrium state instead of collapsing to a black hole. The low density black holes introduced here, if they exist, can be observed through weak and strong gravitational lensing effects. Finally we observe that we obtained here a cosmological model which is capable to explain in a qualitative way the void formation together with the value $\\Omega=1$. But we remark that it needs to be improved by considering non spherical symmetric black holes.

  20. Primordial Black Hole Baryogenesis

    CERN Document Server

    Baumann, D; Turok, N G; Baumann, Daniel; Steinhardt, Paul J.; Turok, Neil

    2007-01-01

    We reconsider the possibility that the observed baryon asymmetry was generated by the evaporation of primordial black holes that dominated the early universe. We present a simple derivation showing that the baryon asymmetry is insensitive to the initial black hole density and the cosmological model but is sensitive to the temperature-dependence of the CP and baryon-violating (or lepton-violating) interactions. We also consider the possibility that black holes stop evaporating and form Planck-mass remnants that act as dark matter. We show that primordial black holes cannot simultaneously account for both the observed baryon asymmetry and the (remnant) dark matter density unless the magnitude of CP violation is much greater than expected from most particle physics models. Finally, we apply these results to ekpyrotic/cyclic models, in which primordial black holes may form when branes collide. We find that obtaining the observed baryon asymmetry is compatible with the other known constraints on parameters.

  1. Black Hole Critical Phenomena Without Black Holes

    CERN Document Server

    Liebling, S L

    2000-01-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  2. Continuity Controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  3. Continuity controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  4. On the Charter Question: Black Marxism and Black Nationalism

    Science.gov (United States)

    Stern, Mark; Hussain, Khuram

    2015-01-01

    This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

  5. New hybrid model of proton exchange membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    WANG Rui-min; CAO Guang-yi; ZHU Xin-jian

    2007-01-01

    Model and simulation are good tools for design optimization of fuel cell systems. This paper proposes a new hybrid model of proton exchange membrane fuel cell (PEMFC). The hybrid model includes physical component and black-box component. The physical component represents the well-known part of PEMFC, while artificial neural network (ANN) component estimates the poorly known part of PEMFC. The ANN model can compensate the performance of the physical model. This hybrid model is implemented on Matlab/Simulink software. The hybrid model shows better accuracy than that of the physical model and ANN model. Simulation results suggest that the hybrid model can be used as a suitable and accurate model for PEMFC.

  6. Agronomic Performance of Flue-Cured Tobacco F1 Hybrids Obtained with Different Sources of Male Sterile Cytoplasm

    Directory of Open Access Journals (Sweden)

    Berbec A

    2014-12-01

    Full Text Available Four cytoplasmic male sterile (cms F1flue-cured hybrids cv. Wiaelica × cv. Virginia Golta (VG, the male fertile analogue and the parental varieties were tested at two locations in Poland in a replicated field trial. The cms sources in the hybrids wereN. suaveolens,N. amplexicaulis,N. bigeloviiand aN. tabacumcms mutant. Under the slight to moderate pressure from black root rot present at the trial sites the hybrids showed a moderate tolerance of the disease characteristic of VG as opposed to medium strong susceptibility of Wislica. Apart from the effect of black root rot tolerance the vegetative vigor of the hybrids (plant height, leaf size, earliness was affected by cytoplasm source. The F1hybrid withN. suaveolens cytoplasm flowered approximately three days later than the remaining hybrids. Of the cms hybrids tested cmsN. bigelovii produced the tallest plants with largest mid-position leaves. Yields of cured leaves were largely influenced by black root rot and were generally higher in VG and in the hybrids than in Wislica. Leaf yields and curability were generally little affected by cms source under low pressure from black root rot. At the site with a relatively high level of black root rot infestation the yields of cmsN. suaveolens were slightly lower but the percentage of light grades slightly higher compared to those of other cms hybrids. CmsN. suaveolens was the best hybrid in terms of money returns at the low black root rot field but it was the poorest hybrid performer under high pressure from the disease. Contents of nitrogen, sugars, nicotine and ash was little affected by source of cms. There was an increased incidence of potato virus Y (PVY and white spots in cmsN. suaveolens and, to a lesser extent, in cmsN. bigelovii as compared to the remaining disease-free entries.

  7. Scalarized Hairy Black Holes

    CERN Document Server

    Kleihaus, Burkhard; Yazadjiev, Stoytcho

    2015-01-01

    In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and ordinary hairy black holes. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  8. Primordial Black Holes

    CERN Document Server

    MacGibbon, Jane H; Linnemann, J T; Marinelli, S S; Stump, D; Tollefson, K

    2015-01-01

    Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic gamma-ray background from the cosmologically-averaged distribution of PBHs and gamma-ray burst signals from individual light black holes. The Fermi, Milagro, Veritas, HESS and HAWC observatories, in combination with new burst recognition methodologies, offer the greatest sensitivity for the detection of such black holes or placing limits on their existence.

  9. Black Hole Entropy

    OpenAIRE

    P. Mitra

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy $S^{BH}$ (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy $S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho})$ (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (...

  10. Black hole entropy

    CERN Document Server

    Frolov, V

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy S^{BH} (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho}) (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (i.e. its independence of the number and properties of the fields which might contribute to S^{SM}) is given.

  11. Scalarized hairy black holes

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)

    2015-05-11

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  12. Scalarized hairy black holes

    Directory of Open Access Journals (Sweden)

    Burkhard Kleihaus

    2015-05-01

    Full Text Available In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  13. Black holes new horizons

    CERN Document Server

    Hayward, Sean Alan

    2013-01-01

    Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

  14. Supercapacitor electrode based on three-dimensional graphene-polyaniline hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Dong Xiaochen; Wang Jingxia [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications NUPT, 9 Wenyuan Road, Nanjing 210046 (China); Wang Jing; Chan-Park, Mary B. [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Li Xingao; Wang Lianhui; Huang Wei [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications NUPT, 9 Wenyuan Road, Nanjing 210046 (China); Chen Peng, E-mail: chenpeng@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore)

    2012-06-15

    Three-dimensional (3D) graphene was synthesized by chemical vapour deposition with nickel foam as a substrate. Based on the 3D graphene foams, free-standing graphene-polyaniline (PANI) hybrids were produced by in-situ polymerization of aniline monomer under acid condition, and characterized by scanning electron microscopy (SEM), Fourier transformation infrared (FTIR), and Raman spectroscopy. Furthermore, we show that supercapacitor electrodes based on the 3D graphene-PANI hybrid exhibit high specific capacitances (346 Fg{sup -1} at a discharge current density of 4 Ag{sup -1}), suggesting that the light and inexpensive 3D graphene foams are a promising candidate for energy storage. - Highlights: Black-Right-Pointing-Pointer Three-dimensional (3D) graphene was synthesized by chemical vapour deposition. Black-Right-Pointing-Pointer Graphene-polyaniline (PANI) hybrids were produced by in-situ polymerization. Black-Right-Pointing-Pointer Graphene-PANI hybrid exhibits high specific capacitances.

  15. The Price of "Black Dominance."

    Science.gov (United States)

    Hoberman, John

    2000-01-01

    Discusses the harmful effects of stereotyping black males as athletes, noting that over-identification with athletes and the world of physical performance limits black children's development by discouraging academic achievement. Examines the negative influence of mass media focus on black athletes, rappers, and stylized ghetto blackness. Discusses…

  16. Feminism and Black Women's Studies.

    Science.gov (United States)

    Hooks, Bell

    1989-01-01

    Women's studies programs have largely ignored Black women. Until Black women's studies courses are developed, feminist scholarship on Black women will not advance, and the contributions of Black women to women's rights movements and African American literature and scholarship may be neglected. (DM)

  17. Black Teenage Pregnancy

    National Research Council Canada - National Science Library

    Loretta I. Winters; Paul C. Winters

    2012-01-01

    .... No difference between Blacks and Whites was found during better economic times. During 2003-2004, the period of greatest economic stress, race was determined to be the only predictor of teenage pregnancy...

  18. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    Black Friday er et godt eksempel på, hvordan ikke kun produktbrands og corporate brands rejser på tværs af landegrænser, men også traditioner som Halloween, Valentines Day og i dette tilfælde den ultimative tilbuds-fredag, som i USA går under navnet Black Friday. Men hvad er Black Friday i Danmark......? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  19. Janus black holes

    Science.gov (United States)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  20. Black hole quantum spectrum

    National Research Council Canada - National Science Library

    Corda, Christian

    2013-01-01

    Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re...

  1. Holographic black hole chemistry

    National Research Council Canada - National Science Library

    Karch, Andreas; Robinson, Brandon

    2015-01-01

    Thermodynamic quantities associated with black holes in Anti-de Sitter space obey an interesting identity when the cosmological constant is included as one of the dynamical variables, the generalized Smarr relation...

  2. Black Teenage Pregnancy

    Directory of Open Access Journals (Sweden)

    Loretta I. Winters

    2012-01-01

    Full Text Available This article examines the relative importance of race and socioeconomic status (SES in determining whether Black and White teenagers report having ever been pregnant. Data gathered from 1999 to 2006 by the National Center for Health Statistics of the Center for Disease Control and Prevention included 1,580 Black and White females aged 15 to 19 years. Results supported the effects of race and SES, with SES having the stronger effect. However, the effects of race and SES differ when controlling for the state of the economy. No difference between Blacks and Whites was found during better economic times. During 2003-2004, the period of greatest economic stress, race was determined to be the only predictor of teenage pregnancy. In particular, during 2005-2006, the reduction in pregnancy rates for Black minors (15-17 fell below those for White minors within their respective SES categories. Policy implications are discussed in light of these findings.

  3. Black Rail Pilot Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Aural surveys using tape recorded calls proved to be an efficient and effective way to survey large expanses of shallow marsh for black rails (Laterallus...

  4. Facile preparation of modified carbon black-LaMnO3 hybrids and the effect of covalent coupling on the catalytic activity for oxygen reduction reaction%改性炭黑-LaMnO3复合材料的制备及其共价复合效应对氧还原性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘景军; 金学民; 宋薇薇; 王峰; 王楠; 宋夜

    2014-01-01

    以Vulcan XC-72炭黑为载体,通过对炭载体石墨化处理和表面化学修饰,将其与化学沉淀法制备的纳米级LaMnO3颗粒共混,再经特定温度下煅烧,制备出改性炭黑-LaMnO3复合材料. X射线光电子能谱和热重分析表明,当煅烧温度在300°C时,炭载体与LaMnO3纳米颗粒之间形成了大量C-O-M (M = La, Mn)化学键.扫描电子显微镜和高分辨透射电子显微镜分析发现,纯相LaMnO3纳米颗粒主要呈现短棒、三支棒或竹节棒的形貌特征,炭载体则为具有完整石墨层的空心球结构, LaMnO3均匀分散在炭载体上.在25°C,1 mol/L NaOH溶液中的电化学测试结果表明,成分比(LaMnO3:C)为2:3的复合材料具有很高的氧还原电催化活性,氧还原反应电子数为3.81,中间产物H2O2产率为9.5%,其活性接近商业Pt/C催化剂(E-TEK).高的氧还原电催化活性主要归因于LaMnO3纳米颗粒与炭载体之间形成了大量共价键.%Covalent coupling between LaMnO3 nanoparticles and carbon black to produce a composite catalyst for oxygen reduction reaction (ORR) was achieved by physical mixing of modified carbon and per-ovskite-type LaMnO3 nanoparticles, followed by sintering at different temperatures. Perovskite-type LaMnO3 nanoparticles were first synthesized via chemical precipitation, and the carbon sup-port (Vulcan XC-72) was modified using graphitization, followed by HNO3 and ammonia treatments. The morphology and electronic states of the carbon black-LaMnO3 hybrid catalyst were character-ized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The loaded LaMnO3 particles featured rod-like, three bars-like, and bamboo rod-like structures and were homogeneously dispersed in the carbon matrix that featured a hollow spherical structure. At a sintering temperature of about 300 °C, C-O-M (M = La, Mn) bonds formed at the interface between the carbon and LaMnO3 nanoparticles. Electrochemical measurements in 1

  5. Highly eccentric inspirals into a black hole

    CERN Document Server

    Osburn, Thomas; Evans, Charles R

    2015-01-01

    We model the inspiral of a compact stellar-mass object into a massive non-rotating black hole including all dissipative and conservative first-order-in-the-mass-ratio effects on the orbital motion. The techniques we develop allow inspirals with initial eccentricities as high as $e\\sim0.8$ and initial separations as large as $\\sim 100M$ to be evolved through many thousands of orbits up to the onset of the plunge into the black hole. The inspiral is computed using an osculating elements scheme driven by a hybridized self-force model, which combines Lorenz-gauge self-force results with highly accurate flux data from a Regge-Wheeler-Zerilli code. The high accuracy of our hybrid self-force model allows the orbital phase of the inspirals to be tracked to within $\\sim0.1$ radians or better. The difference between self-force models and inspirals computed in the radiative approximation is quantified.

  6. Braneworld black holes

    CERN Document Server

    Gregory, Ruth

    2008-01-01

    In these lectures, I give an introduction to and overview of braneworlds and black holes in the context of warped compactifications. I first describe the general paradigm of braneworlds, and introduce the Randall-Sundrum model. I discuss braneworld gravity, both using perturbation theory, and also non perturbative results. I then discuss black holes on the brane, the obstructions to finding exact solutions, and ways of tackling these difficulties. I describe some known solutions, and conclude with some open questions and controversies.

  7. Black Is Cool!

    Institute of Scientific and Technical Information of China (English)

    Dorine; Houston

    1997-01-01

    Do you remember the colors the college freshmen dyed their hair when you were here? Turquoise, orange, bright yellow.... Things have changed. Black has (?)ome the color of choice among the young people. Young men and women alike dye their hair coal black. The women let their hair grow very long. and it hangs straight and stringy down their backs. The young men leave it long on

  8. Modelling quantum black hole

    CERN Document Server

    Govindarajan, T R

    2016-01-01

    Novel bound states are obtained for manifolds with singular potentials. These singular potentials require proper boundary conditions across boundaries. The number of bound states match nicely with what we would expect for black holes. Also they serve to model membrane mechanism for the black hole horizons in simpler contexts. The singular potentials can also mimic expanding boundaries elegantly, there by obtaining appropriately tuned radiation rates.

  9. Hydrodynamics and black holes

    CERN Document Server

    Oz, Yaron

    2015-01-01

    This chapter describes how the AdS/CFT correspondence (the Holographic Principle) relates field theory hydrodynamics to perturbations of black hole (brane) gravitational backgrounds. The hydrodynamics framework is first presented from the field theory point of view, after which the dual gravitational description is outlined, first for relativistic fluids and then for the nonrelativistic case. Further details of the fluid/gravity correspondence are then discussed, including the bulk geometry and the dynamics of the black hole horizon.

  10. Black hole geometrothermodynamics

    Science.gov (United States)

    Quevedo, Hernando

    2017-03-01

    We review the main aspects of geometrothermodynamics which is a geometric formalism to describe thermodynamic systems, taking into account the invariance of classical thermodynamics with respect to Legendre transformations. We focus on the particular case of black holes, and present a Riemannian metric which describes the corresponding space of equilibrium states. We show that this metric can be used to describe the stability properties and phase transition structure of black holes in different gravity theories.

  11. Helical superconducting black holes.

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  12. Black Hole Induced Ejections

    OpenAIRE

    Pelletier, G.

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy a...

  13. Cosmic censorship inside black holes

    CERN Document Server

    Thorlacius, L

    2006-01-01

    A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.

  14. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Steven L Liebling

    2000-10-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  15. Charged Galileon black holes

    Science.gov (United States)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  16. Ultramassive Black Hole Coalescence

    CERN Document Server

    Khan, Fazeel; Berczik, Peter

    2015-01-01

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gr...

  17. Black holes and beyond

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

  18. Black-carbon absorption enhancement in the atmosphere determined by particle mixing state

    Science.gov (United States)

    Liu, Dantong; Whitehead, James; Alfarra, M. Rami; Reyes-Villegas, Ernesto; Spracklen, Dominick V.; Reddington, Carly L.; Kong, Shaofei; Williams, Paul I.; Ting, Yu-Chieh; Haslett, Sophie; Taylor, Jonathan W.; Flynn, Michael J.; Morgan, William T.; McFiggans, Gordon; Coe, Hugh; Allan, James D.

    2017-02-01

    Atmospheric black carbon makes an important but poorly quantified contribution to the warming of the global atmosphere. Laboratory and modelling studies have shown that the addition of non-black-carbon materials to black-carbon particles may enhance the particles’ light absorption by 50 to 60% by refracting and reflecting light. Real-world experimental evidence for this `lensing’ effect is scant and conflicting, showing that absorption enhancements can be less than 5% or as large as 140%. Here we present simultaneous quantifications of the composition and optical properties of individual atmospheric black-carbon particles. We show that particles with a mass ratio of non-black carbon to black carbon of less than 1.5, which is typical of fresh traffic sources, are best represented as having no absorption enhancement. In contrast, black-carbon particles with a ratio greater than 3, which is typical of biomass-burning emissions, are best described assuming optical lensing leading to an absorption enhancement. We introduce a generalized hybrid model approach for estimating scattering and absorption enhancements based on laboratory and atmospheric observations. We conclude that the occurrence of the absorption enhancement of black-carbon particles is determined by the particles’ mass ratio of non-black carbon to black carbon.

  19. Impacts of flushing and fermentation times on the quality of black tea

    OpenAIRE

    Ansari Hojjat Reza; Asil Hassanpour Moazzam; Rabiei Babak; Dadashpour Ahmad

    2011-01-01

    Flushing and fermentation times are the two main parameters determining the quality of black tea. In this research, the effects of different flushing and fermentation times were studied on the quality of black tea in two clones, 100 and natural Chinese hybrid. Analysis of variance showed there were the significant differences between the clone types, flushing and fermentation times for theaflavin, thearubigin, total color, brightness, tannin and caffeine. C...

  20. Thermodynamic black di-rings

    CERN Document Server

    Iguchi, Hideo

    2010-01-01

    Previously the five dimensional $S^1$-rotating black rings have been superposed in concentric way by some solitonic methods and regular systems of two $S^1$-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions black di-rings). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution-sets of the black di-rings. Then the existence of thermodynamic black di-rings are shown, in which both iso-thermality and iso-rotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  1. Hybrid metric-Palatini stars

    Science.gov (United States)

    Danilǎ, Bogdan; Harko, Tiberiu; Lobo, Francisco S. N.; Mak, M. K.

    2017-02-01

    quark matter. As a possible astrophysical application of the obtained results, we suggest that stellar mass black holes, with masses in the range of 3.8 and 6 M⊙ , respectively, could be in fact hybrid metric-Palatini gravity neutron or quark stars.

  2. Charged Galileon black holes

    CERN Document Server

    Babichev, Eugeny; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...

  3. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  4. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  5. The Hybrid Museum: Hybrid Economies of Meaning

    DEFF Research Database (Denmark)

    Vestergaard, Vitus

    2013-01-01

    this article shows that there are two different museum mindsets where the second mindset leans towards participatory practices. It is shown how a museum can support a hybrid economy of meaning that builds on both a user generated economy of meaning and an institutional economy of meaning and adds value to both....... Such a museum is referred to as a hybrid museum....

  6. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  7. Hybrid Management in Hospitals

    DEFF Research Database (Denmark)

    Byrkjeflot, Haldor; Jespersen, Peter Kragh

    2010-01-01

    Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

  8. Black Afrikaans: An alternative use

    Directory of Open Access Journals (Sweden)

    Anna P. Maritz

    2016-09-01

    Full Text Available This article provides a first look at the nature of the alternative functions of Black Afrikaans. These functions realise when Black Afrikaans is imitated by Afrikaans mother-tongue speakers. The functions of the alternative use of Black Afrikaans centre on: the social nature of the variety, sensitivity as a deciding role-player, identity, humour, inclusivity and exclusivity, language repertoire and similar variety. Furthermore, because of the direct relationship between Black Afrikaans, Pidginised Afrikaans and the imitation of Black Afrikaans, these varieties are compared to establish a starting point description for the imitation of Black Afrikaans, as the variety has not yet been described.

  9. 剑尾鱼P-糖蛋白基因全长cDNA克隆、分析及组织分布%P-GLYCOPROTEIN OF SWORDTAIL FISH XIPHOPHORUS HELLERI:cDNA CLONING, BIOINFORMATIC AND TISSUE-SPECIFIC EXPRESSION ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    王芳; 李凯彬; 聂湘平; 刘春; 劳海华; 王英英; 梁慧丽; 吴淑勤

    2013-01-01

    P-glycoprotein is one of the major members of the ATP-binding cassette (ABC) superfamily which prevented in plasma membrane, utilizes the energy of ATP hydrolysis to transport various substrates across celluar membranes, functions as an export pump that decreases intracellular concentrations of xenobiotic agents. In our experiment, RT-PCR and RACE-PCR were used for P-gp gene cloning in swordtail fish Xiphophorus helleri. The full-length of P-gp cDNA for swordtail fish was 4301 bp with open reading frame (ORF) of 3861 bp encoding a polypeptide of 1286 amino acids. The calculated MW was of 141.64 kD and a theoretical pI of 7.06. Bioinformatics analysis indicated that the deduced amino acid sequence contained striking features of the P-gp including four core regions, two transmembrane domains (TMD) and two nucleotide-binding domains (NBD) but no signal peptide. Each TMD had six transmembrane helices while NBD contained the highly conserved motif Walker A, Walker B, ABC transporters family signature, D-loop, H-loop, Q-loop and Signature C (L-S-G-G-Q). The deduced amino acid sequence aligned with those of P-gp genes from different species also displayed high degree of sequential homology as was shown by the phylogenic tree. The gene of P-gp was expressed in all examined organs in swordtail fish and had a significantly high expression in liver, so it will be major organ for P-gp examination. Our results also showed that the hepatic P-gp expression of swordtail fish can be significantly upregulated with the exposure of benzo (a) pyrene. Therefore, the reaction of P-gp in the fish to the expo-sure of various xenobiotics can thus be used as a potential biomarker for monitoring environmental pollution.%P-糖蛋白(P-glycoprotein, P-gp)为ABC转运体超家族的主要成员,分布于细胞膜,依赖ATP供能,可将细胞内的亲脂性毒物或药物逆浓度泵出胞外,在机体解毒上具重要功能。研究采用RT-PCR和RACE法对剑尾鱼P-gp基

  10. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  11. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  12. Realizing the Hybrid Library.

    Science.gov (United States)

    Pinfield, Stephen; Eaton, Jonathan; Edwards, Catherine; Russell, Rosemary; Wissenburg, Astrid; Wynne, Peter

    1998-01-01

    Outlines five projects currently funded by the United Kingdom's Electronic Libraries Program (eLib): HyLiFe (Hybrid Library of the Future), MALIBU (MAnaging the hybrid Library for the Benefit of Users), HeadLine (Hybrid Electronic Access and Delivery in the Library Networked Environment), ATHENS (authentication scheme), and BUILDER (Birmingham…

  13. Homoploid hybrid expectations

    Science.gov (United States)

    Homoploid hybrid speciation occurs when a stable, fertile, and reproductively isolated lineage results from hybridization between two distinct species without a change in ploidy level. Reproductive isolation between a homoploid hybrid species and its parents is generally attained via chromosomal re...

  14. Hybrid armature projectile

    Science.gov (United States)

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  15. Intraply Hybrid Composite Design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1986-01-01

    Several theoretical approaches combined in program. Intraply hybrid composites investigated theoretically and experimentally at Lewis Research Center. Theories developed during investigations and corroborated by attendant experiments used to develop computer program identified as INHYD (Intraply Hybrid Composite Design). INHYD includes several composites micromechanics theories, intraply hybrid composite theories, and integrated hygrothermomechanical theory. Equations from theories used by program as appropriate for user's specific applications.

  16. Hybrid quantum information processing

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

    2014-12-04

    I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

  17. Black hole entropy quantization

    CERN Document Server

    Corichi, A; Fernandez-Borja, E; Corichi, Alejandro; Diaz-Polo, Jacobo; Fernandez-Borja, Enrique

    2006-01-01

    Ever since the pioneer works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show that an observed oscillatory behavior in the entropy-area relation, when properly interpreted yields an entropy that has discrete, equidistant values that are consistent with the Bekenstein framework.

  18. Black hole gravitohydromagnetics

    CERN Document Server

    Punsly, Brian

    2008-01-01

    Black hole gravitohydromagnetics (GHM) is developed from the rudiments to the frontiers of research in this book. GHM describes plasma interactions that combine the effects of gravity and a strong magnetic field, in the vicinity (ergosphere) of a rapidly rotating black hole. This topic was created in response to the astrophysical quest to understand the central engines of radio loud extragalactic radio sources. The theory describes a "torsional tug of war" between rotating ergospheric plasma and the distant asymptotic plasma that extracts the rotational inertia of the black hole. The recoil from the struggle between electromagnetic and gravitational forces near the event horizon is manifested as a powerful pair of magnetized particle beams (jets) that are ejected at nearly the speed of light. These bipolar jets feed large-scale magnetized plasmoids on scales as large as millions of light years (the radio lobes of extragalactic radio sources). This interaction can initiate jets that transport energy fluxes exc...

  19. The closest black holes

    CERN Document Server

    Fender, Rob; Heywood, Ian

    2013-01-01

    Starting from the assumption that there is a large population (> 10^8) of isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that may be associated with such a population. We simulate the nearby (radius 250 pc) part of this population, corresponding to the closest ~35 000 black holes, using current best estimates of the mass distribution of stellar mass black holes combined with two models for the velocity distribution of stellar-mass IBH which bracket likely possibilities. We distribute this population of objects appropriately within the different phases of the ISM and calculate the Bondi-Hoyle accretion rate, modified by a further dimensionless efficiency parameter \\lambda. Assuming a simple prescription for radiatively inefficient accretion at low Eddington ratios, we calculate the X-ray luminosity of these objects, and similarly estimate the radio luminosity from relations found empirically for b...

  20. Turbulent black holes.

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  1. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  2. Photon Black Holes

    CERN Document Server

    Hernández, X; Mendoza, S; Sussman, R A

    2005-01-01

    We study the relationship between the energy and entropy of a black body photon gas, within an idealised spherical adiabatic enclosure of radius R, as this is compressed into a self-gravitating regime. We show that this regime approximately coincides with the black hole regime for the system, i.e., R ~ R_{s}, where R_{s} denotes the Schwarzschild radius of the system. The entropy of this system is always below the suggested Holographic bound, even as R \\to R_{s}. A plausible quantum configuration for the photon gas at R \\to R_{s} is suggested, which satisfies all energy, entropy and temperature black hole conditions. Finally we examine our results from the point of view of recent Loop Quantum Gravity ideas.

  3. Black Hole Induced Ejections

    CERN Document Server

    Pelletier, G

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy astrophysics. The combination of General Relativity and Magneto-HydroDynamics (MHD) makes theory difficult; however great pionneers opened beautiful tracks in the seventies and left important problems to be solved for the next decades. These lectures will present the status of these issues. They have a tutorial aspect together with critical review aspect and contain also some new issues. Most of these lectures has been presented at the "School on Black Hole in the Universe" at Cargese, in May 2003.

  4. Black hole accretion discs

    CERN Document Server

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  5. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  6. Diagnoses of hybrid hummingbirds (Aves: Trochilidae). 17. Documentation of the intrageneric hybrid (Archilochus colubris × Archilochus alexandri)

    DEFF Research Database (Denmark)

    Graves, Gary R.; Dittmann, Donna L.; Cardiff, Steven W.

    2016-01-01

    Although the breeding ranges of Archilochus alexandri (Black-chinned Hummingbird) and Archilochus colubris (Ruby throated Hummingbird) are narrowly parapatric in central Texas and central and southern Oklahoma, there have been few reports of hybridization in the literature and no well-documented ......Although the breeding ranges of Archilochus alexandri (Black-chinned Hummingbird) and Archilochus colubris (Ruby throated Hummingbird) are narrowly parapatric in central Texas and central and southern Oklahoma, there have been few reports of hybridization in the literature and no well...

  7. Superfluid Black Holes

    CERN Document Server

    Hennigar, Robie A; Tjoa, Erickson

    2016-01-01

    We present what we believe is the first example of a "$\\lambda$-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid $^4$He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically AdS hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  8. Are Black Holes Springy?

    OpenAIRE

    Good, Michael R. R.; Ong, Yen Chin

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conj...

  9. Are Black Holes Springy?

    CERN Document Server

    Good, Michael R R

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.

  10. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  11. Superfluid Black Holes.

    Science.gov (United States)

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  12. Black Brane World Scenarios

    CERN Document Server

    Moon, S H

    2001-01-01

    We consider a brane world residing in the interior region inside the horizon of extreme black branes. In this picture, the size of the horizon can be interpreted as the compactification size. The large mass hierarchy is simply translated into the large horizon size, which is provided by the magnitude of charges carried by the black branes. Hence, the macroscopic compactification size is a quantity calculable from the microscopic theory which has only one physical scale, and its stabilization is guaranteed from the charge conservation.

  13. Horndeski black hole geodesics

    CERN Document Server

    Tretyakova, D A

    2016-01-01

    We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.

  14. Modeling black hole evaporation

    CERN Document Server

    Fabbri, Alessandro

    2005-01-01

    The scope of this book is two-fold: the first part gives a fully detailed and pedagogical presentation of the Hawking effect and its physical implications, and the second discusses the backreaction problem, especially in connection with exactly solvable semiclassical models that describe analytically the black hole evaporation process. The book aims to establish a link between the general relativistic viewpoint on black hole evaporation and the new CFT-type approaches to the subject. The detailed discussion on backreaction effects is also extremely valuable.

  15. Acoustic black holes

    CERN Document Server

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  16. Bulletproof Black Man

    DEFF Research Database (Denmark)

    Højer, Henrik

    2016-01-01

    Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst.......Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst....

  17. Quantum aspects of black holes

    CERN Document Server

    2015-01-01

    Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

  18. Conquering the Black Girl Blues.

    Science.gov (United States)

    Jones, Lani Valencia; Guy-Sheftall, Beverly

    2015-10-01

    An examination of the literature on epidemiology, etiology, and use of services for this population reveals an insufficient application of culturally congruent approaches to intervening with black women. An exploration of the social work practice literature and other relevant fields indicate that black feminist perspectives offer the opportunity to gain a clearer understanding of the intersection and influence of oppression among black women struggling with psychiatric issues and provide a useful framework for mental health practice with this population. This article discusses the evolving black feminist thought and summarizes the scholarship on black women's mental health services needs and utilization issues. The article includes a discussion of black feminisms as an emerging mental health perspective, arguing that black feminist perspectives in therapy provide an ideal framework for services that are responsive to the values and health needs of black women. The article concludes with a case vignette that illustrates some of its points.

  19. Meer bekend over Black Mold

    NARCIS (Netherlands)

    Duyvesteijn, R.G.E.; Kohrman, E.

    2008-01-01

    In de vollegrondsrozenteelt zorgde Black Mold in 2007 voor een groot aantal mislukte oculaties. In 2008 waren er aanzienlijk minder problemen. Uit onderzoek is meer bekend over de oorzaak en bestrijding van Black Mold.

  20. Reflections on a Black Mirror

    CERN Document Server

    Good, Michael R R

    2016-01-01

    A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.

  1. Meer bekend over Black Mold

    NARCIS (Netherlands)

    Duyvesteijn, R.G.E.; Kohrman, E.

    2008-01-01

    In de vollegrondsrozenteelt zorgde Black Mold in 2007 voor een groot aantal mislukte oculaties. In 2008 waren er aanzienlijk minder problemen. Uit onderzoek is meer bekend over de oorzaak en bestrijding van Black Mold.

  2. Black Sea Bass genetic connectivity

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microsatellite analysis of black sea bass was undertaken to determine magnitude and direction of mixing of black seabass across the Hatteras boundary, as well as...

  3. Hybrid Dynamic Network Data Envelopment Analysis

    Directory of Open Access Journals (Sweden)

    Ling Li

    2015-01-01

    Full Text Available Conventional DEA models make no hypothesis concerning the internal operations in a static situation. To open the “black box” and work with dynamic assessment issues synchronously, we put forward a hybrid model for evaluating the relative efficiencies of a set of DMUs over an observed time period with a composite of network DEA and dynamic DEA. We vertically deal with intermediate products between divisions with assignable inputs in the network structure and, horizontally, we extend network structure by means of a dynamic pattern with unrelated activities between two succeeding periods. The hybrid dynamic network DEA model proposed in this paper enables us to (i pry into the internal operations of DEA by another network structure, (ii obtain dynamic change of period efficiency, and (iii gain the overall dynamic efficiency of DMUs over the entire observed periods. We finally illustrate the calculation procedure of the proposed approach by a numerical example.

  4. The hydrogen hybrid option

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.R.

    1993-10-15

    The energy efficiency of various piston engine options for series hybrid automobiles are compared with conventional, battery powered electric, and proton exchange membrane (PEM) fuel cell hybrid automobiles. Gasoline, compressed natural gas (CNG), and hydrogen are considered for these hybrids. The engine and fuel comparisons are done on a basis of equal vehicle weight, drag, and rolling resistance. The relative emissions of these various fueled vehicle options are also presented. It is concluded that a highly optimized, hydrogen fueled, piston engine, series electric hybrid automobile will have efficiency comparable to a similar fuel cell hybrid automobile and will have fewer total emissions than the battery powered vehicle, even without a catalyst.

  5. Black ducks and their Chesapeake Bay habitats : proceedings of a symposium

    Science.gov (United States)

    Perry, Matthew C.

    2002-01-01

    The symposium 'Black Ducks and Their Chesapeake Bay Habitats,' held October 4, 2000, provided a forum for scientists to share research about the American black duck (Anas rubripes), an important breeding and wintering waterfowl species dependent upon the Chesapeake Bay habitats. American black ducks have declined significantly in the last 50 years and continue to be a species of management concern. The symposium, sponsored by the Wildfowl Trust of North America and the U.S. Geological Survey, highlighted papers and posters on a range of topics, from the traditional concerns of hunting, habitat, and hybridization to the more recent concerns of human disturbance and neophobia. Other presentations provided a historical perspective of black duck management. The direction that black duck conservation initiatives could and/or should take in the future was also discussed. As populations of humans in the Chesapeake Bay region continue to increase, we can expect that these subjects will receive increased discussion in the future.

  6. Towards Noncommutative Quantum Black Holes

    CERN Document Server

    Lopez-Dominguez, J C; Ramírez, C; Sabido, M

    2006-01-01

    In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Trough the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular we calculate the Hawking's temperature and entropy for the Noncommutative Schwarzschild black hole.

  7. Black Holes in Higher Dimensions

    Directory of Open Access Journals (Sweden)

    Reall Harvey S.

    2008-09-01

    Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

  8. Black Hole: The Interior Spacetime

    CERN Document Server

    Ong, Yen Chin

    2016-01-01

    The information loss paradox is often discussed from the perspective of the observers who stay outside of a black hole. However, the interior spacetime of a black hole can be rather nontrivial. We discuss the open problems regarding the volume of a black hole, and whether it plays any role in information storage. We also emphasize the importance of resolving the black hole singularity, if one were to resolve the information loss paradox.

  9. The Black Ring is Unstable

    CERN Document Server

    Santos, Jorge E

    2015-01-01

    We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.

  10. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  11. Spoof Plasmon Hybridization

    CERN Document Server

    Zhang, Jingjing; Luo, Yu; Shen, Xiaopeng; Maier, Stefan A; Cui, Tie Jun

    2016-01-01

    Plasmon hybridization between closely spaced nanoparticles yields new hybrid modes not found in individual constituents, allowing for the engineering of resonance properties and field enhancement capabilities of metallic nanostructure. Experimental verifications of plasmon hybridization have been thus far mostly limited to optical frequencies, as metals cannot support surface plasmons at longer wavelengths. Here, we introduce the concept of 'spoof plasmon hybridization' in highly conductive metal structures and investigate experimentally the interaction of localized surface plasmon resonances (LSPR) in adjacent metal disks corrugated with subwavelength spiral patterns. We show that the hybridization results in the splitting of spoof plasmon modes into bonding and antibonding resonances analogous to molecular orbital rule and plasmonic hybridization in optical spectrum. These hybrid modes can be manipulated to produce enormous field enhancements (larger than 5000) by tuning the separation between disks or alte...

  12. Simulations of coalescing black holes

    CERN Document Server

    Janiuk, Agnieszka

    2016-01-01

    We describe the methods and results of numerical simulations of coalescing black holes. The simulation in dynamical spacetime covers the inspiral, merger, and ringdown phases. We analyze the emission of gravitational waves and properties of a black hole being the merger product. We discuss the results in the context of astrophysical environment of black holes that exist in the Universe.

  13. "Exotic" black holes with torsion

    OpenAIRE

    2013-01-01

    In the context of three-dimensional gravity with torsion, the concepts of standard and "exotic" Banados-Teitelboim-Zanelli black holes are generalized by going over to black holes with torsion. This approach provides a unified insight into thermodynamics of black holes, with or without torsion.

  14. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for

  15. Health Issues Facing Black Women.

    Science.gov (United States)

    Reid, Inez Smith

    Black women in the United States experience a high incidence of serious health problems and, as a group, receive insufficient and inadequate medical care. The death rate for black women suffering from breast cancer has increased substantially since 1950. Also of great concern is the high incidence of cervical cancer in low income black women…

  16. Black-spot poison ivy.

    Science.gov (United States)

    Schram, Sarah E; Willey, Andrea; Lee, Peter K; Bohjanen, Kimberly A; Warshaw, Erin M

    2008-01-01

    In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most common cause of allergic contact dermatitis in the United States, black-spot poison ivy dermatitis is relatively rare.

  17. Black silicon with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

  18. Rotating regular black holes

    CERN Document Server

    Bambi, Cosimo

    2013-01-01

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this letter, we apply the Newman-Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer-Lindquist coordinates. These special solutions are of Petrov type ...

  19. Rotating black hole hair

    CERN Document Server

    Gregory, Ruth; Wills, Danielle

    2013-01-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that a such a system displays much richer phenomenology than its static Schwarzschild or Reissner--Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: Large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is con...

  20. and black cumin

    African Journals Online (AJOL)

    and black cumin (Nigella sativa) seeds on yield, oxidative stability and sensory properties of cold pressed oil .... to the recommended practice for panel sensory evaluation of edible vegetable oils by (AOCS-. Cg2-83). Oil samples (20 mL) were ...

  1. Moulting Black Holes

    Science.gov (United States)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  2. Twistors and Black Holes

    NARCIS (Netherlands)

    Neitzke, A.; Pioline, B.; Vandoren, S.

    2007-01-01

    Motivated by black hole physics in N = 2,D = 4 supergravity, we study the geometry of quaternionic-K¨ahler manifolds Mobtained by the c-map construction from projective special Kähler manifolds Ms. Improving on earlier treatments, we compute the Käahler potentials on the twistor space Z and Swann sp

  3. Rotating regular black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bambi, Cosimo, E-mail: bambi@fudan.edu.cn; Modesto, Leonardo, E-mail: lmodesto@fudan.edu.cn

    2013-04-25

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this Letter, we apply the Newman–Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer–Lindquist coordinates. These special solutions are of Petrov type D, they are singularity free, but they violate the weak energy condition for a non-vanishing spin and their curvature invariants have different values at r=0 depending on the way one approaches the origin. We propose a natural prescription to have rotating solutions with a minimal violation of the weak energy condition and without the questionable property of the curvature invariants at the origin.

  4. When Black Holes Collide

    Science.gov (United States)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  5. Newborn Black Holes

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  6. Gasification of black liquor

    Science.gov (United States)

    Kohl, Arthur L.

    1987-07-28

    A concentrated aqueous black liquor containing carbonaceous material and alkali metal sulfur compounds is treated in a gasifier vessel containing a relatively shallow molten salt pool at its bottom to form a combustible gas and a sulfide-rich melt. The gasifier vessel, which is preferably pressurized, has a black liquor drying zone at its upper part, a black liquor solids gasification zone located below the drying zone, and a molten salt sulfur reduction zone which comprises the molten salt pool. A first portion of an oxygen-containing gas is introduced into the gas space in the gasification zone immediatley above the molten salt pool. The remainder of the oxygen-containing gas is introduced into the molten salt pool in an amount sufficient to cause gasification of carbonaceous material entering the pool from the gasification zone but not sufficient to create oxidizing conditions in the pool. The total amount of the oxygen-containing gas introduced both above the pool and into the pool constitutes between 25 and 55% of the amount required for complete combustion of the black liquor feed. A combustible gas is withdrawn from an upper portion of the drying zone, and a melt in which the sulfur content is predominantly in the form of alkali metal sulfide is withdrawn from the molten salt sulfur reduction zone.

  7. Nonsingular black hole

    Energy Technology Data Exchange (ETDEWEB)

    Chamseddine, Ali H. [American University of Beirut, Physics Department, Beirut (Lebanon); I.H.E.S., Bures-sur-Yvette (France); Mukhanov, Viatcheslav [Niels Bohr Institute, Niels Bohr International Academy, Copenhagen (Denmark); Ludwig-Maximilians University, Theoretical Physics, Munich (Germany); MPI for Physics, Munich (Germany)

    2017-03-15

    We consider the Schwarzschild black hole and show how, in a theory with limiting curvature, the physical singularity ''inside it'' is removed. The resulting spacetime is geodesically complete. The internal structure of this nonsingular black hole is analogous to Russian nesting dolls. Namely, after falling into the black hole of radius r{sub g}, an observer, instead of being destroyed at the singularity, gets for a short time into the region with limiting curvature. After that he re-emerges in the near horizon region of a spacetime described by the Schwarzschild metric of a gravitational radius proportional to r{sub g}{sup 1/3}. In the next cycle, after passing the limiting curvature, the observer finds himself within a black hole of even smaller radius proportional to r{sub g}{sup 1/9}, and so on. Finally after a few cycles he will end up in the spacetime where he remains forever at limiting curvature. (orig.)

  8. Marine Fish Hybridization

    KAUST Repository

    He, Song

    2017-04-01

    Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

  9. Black Strings, Black Rings and State-space Manifold

    CERN Document Server

    Bellucci, Stefano

    2011-01-01

    State-space geometry is considered, for diverse three and four parameter non-spherical horizon rotating black brane configurations, in string theory and $M$-theory. We have explicitly examined the case of unit Kaluza-Klein momentum $D_1D_5P$ black strings, circular strings, small black rings and black supertubes. An investigation of the state-space pair correlation functions shows that there exist two classes of brane statistical configurations, {\\it viz.}, the first category divulges a degenerate intrinsic equilibrium basis, while the second yields a non-degenerate, curved, intrinsic Riemannian geometry. Specifically, the solutions with finitely many branes expose that the two charged rotating $D_1D_5$ black strings and three charged rotating small black rings consort real degenerate state-space manifolds. Interestingly, arbitrary valued $M_5$-dipole charged rotating circular strings and Maldacena Strominger Witten black rings exhibit non-degenerate, positively curved, comprehensively regular state-space con...

  10. Growth of Primordial Black Holes

    Science.gov (United States)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.

  11. Over spinning a black hole?

    Energy Technology Data Exchange (ETDEWEB)

    Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

    2011-09-22

    A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

  12. BlackBerry For Dummies

    CERN Document Server

    Kao, Robert

    2010-01-01

    Get the most juice out of your BlackBerry handheld!. Feature-rich and complex, the BlackBerry is the number one smartphone in the corporate world is among the most popular handhelds for business users. This new and updated edition includes all the latest and greatest information on new and current BlackBerry mobile devices. Covering a range of valuable how-to topics, this helpful guide explores the BlackBerry's most useful features, techniques for getting the most out of your BlackBerry, and practical information about power usage.: Covers all aspects of the number one smartphone in the corpor

  13. Philosophical Issues of Black Holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Black holes are extremely relativistic objects. Physical processes around them occur in a regime where the gravitational field is extremely intense. Under such conditions, our representations of space, time, gravity, and thermodynamics are pushed to their limits. In such a situation philosophical issues naturally arise. In this chapter I review some philosophical questions related to black holes. In particular, the relevance of black holes for the metaphysical dispute between presentists and eternalists, the origin of the second law of thermodynamics and its relation to black holes, the problem of information, black holes and hypercomputing, the nature of determinisim, and the breakdown of predictability in black hole space-times. I maintain that black hole physics can be used to illuminate some important problems in the border between science and philosophy, either epistemology and ontology.

  14. Phoma Macdonaldi on seed and its importance in etiology of Phoma black stem in sunflower

    Directory of Open Access Journals (Sweden)

    Maširević Stevan N.

    2014-01-01

    Full Text Available Phoma macdonaldi Boerema, teleomorph Leptosphaeria lindquistii Frezzi, is a widespread pathogen of sunflower. The aim of this research was to identify the presence of fungus P. macdonaldi in seed of different sunflower hybrids, as well as the correlation between seed and field infection. Phoma black stem assessment was performed on three hybrids grown in six localities in Serbia. Untreated and processed seeds of these hybrids were used in the seed health test. Severity of the disease did not differ between localities. Average disease index for hybrids H7, H9 and H19 was 14.01%, 13.25% and 11.83% respectively, and it shows that there are no significant differences in hybrid susceptibility. The index of disease indicates tolerance of these hybrids to Phoma black stem. Seed analysis showed the presence of fungi from the following genera: Phoma, Alternaria, Botrytis, Sclerotinia, Penicillium and Aspergillus. Seed infection with Phoma (of the untreated seeds per hybrid ranged from 1.2-3.5%. There is no significant correlation between stem and seed infection.

  15. Henkin and Hybrid Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria;

    2014-01-01

    Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

  16. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  17. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  18. HYBRID VEHICLE CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2016-06-01

    Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

  19. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Hybrid radiator cooling system

    Science.gov (United States)

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  1. Optical black hole lasers

    CERN Document Server

    Faccio, Daniele; Lamperti, Marco; Leonhardt, Ulf

    2012-01-01

    Using numerical simulations we show how to realise an optical black hole laser, i.e. an amplifier formed by travelling refractive index perturbations arranged so as to trap light between a white and a black hole horizon. The simulations highlight the main features of these lasers: the growth inside the cavity of positive and negative frequency modes accompanied by a weaker emission of modes that occurs in periodic bursts corresponding to the cavity round trips of the trapped modes. We then highlight a new regime in which the trapped mode spectra broaden until the zero-frequency points on the dispersion curve are reached. Amplification at the horizon is highest for zero-frequencies, therefore leading to a strong modification of the structure of the trapped light. For sufficiently long propagation times, lasing ensues only at the zero-frequency modes.

  2. Presentism meets black holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Presentism is, roughly, the metaphysical doctrine that maintains that whatever exists, exists in the present. The compatibility of presentism with the theories of special and general relativity was much debated in recent years. It has been argued that at least some versions of presentism are consistent with time-orientable models of general relativity. In this paper we confront the thesis of presentism with relativistic physics, in the strong gravitational limit where black holes are formed. We conclude that the presentist position is at odds with the existence of black holes and other compact objects in the universe. A revision of the thesis is necessary, if it is intended to be consistent with the current scientific view of the universe.

  3. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  4. Hybrid Unifying Variable Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    In order to compare new phenomenon of topology change,evolution,hybrid ratio and network characteristics of unified hybrid network theoretical model with unified hybrid supernetwork model,this paper constructed unified hybrid variable supernetwork model(HUVSM).The first layer introduces a hybrid ratio dr,the

  5. Large Unifying Hybrid Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    For depicting multi-hybrid process,large unifying hybrid network model(so called LUHNM)has two sub-hybrid ratios except dr.They are deterministic hybrid ratio(so called fd)and random hybrid ratio(so called gr),respectively.

  6. France in Black Africa,

    Science.gov (United States)

    1989-01-01

    mediation role between African governments and their private creditors. 123 France in Black Africa To further complicate matters, France herself is...34La coop6ration Franco-Ivoirienne, annde 1986," Mission de Cooperation et d’Action Culturelle , Ambassade de France en C6te D’Ivoire, Abidjan, 1987, p. 8...Ministry in "La France et l’Afrique: Etude des relations Franco-Africaines politiques, finan- cires, economiques, commerciales et culturelles ," Paris, 1984

  7. Noncommutative Black Holes

    CERN Document Server

    Bastos, C; Dias, N C; Prata, J N

    2010-01-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity regime and it is shown that the wave function vanishes in this limit.

  8. Life Inside Black Holes

    Science.gov (United States)

    Dokuchaev, Vyacheslav

    2013-11-01

    It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.

  9. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    ? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  10. Black Hair is Beautiful

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    On June 9, the 1994 ⅩⅢ Asian Make-up and Hairstyling Competition was held in Beijing. More than 200 contestants from 12 countries and regions across Asia participated. The competition is now considered the largest and most prestigious exchange activity in Asian beauty and hair circles. Black Hair is Beautiful" was the theme of this competition, which stressed Asian physical characteristics and aesthetics.

  11. Hybrid Rocket Technology

    National Research Council Canada - National Science Library

    Sankaran Venugopal; K K Rajesh; V Ramanujachari

    2011-01-01

    With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems...

  12. Hybrid FOSS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers are continuing their efforts to further develop FOSS technologies. A hybrid FOSS technique (HyFOSS) employs conventional continuous grating...

  13. Linear dilaton black holes

    CERN Document Server

    Clément, G; Leygnac, C; Clement, Gerard; Gal'tsov, Dmitri; Leygnac, Cedric

    2003-01-01

    We present new solutions to Einstein-Maxwell-dilaton-axion (EMDA) gravity in four dimensions describing black holes which asymptote to the linear dilaton background. In the non-rotating case they can be obtained as the limiting geometry of dilaton black holes. The rotating solutions (possibly endowed with a NUT parameter) are constructed using a generating technique based on the Sp(4,R) duality of the EMDA system. In a certain limit (with no event horizon present) our rotating solutions coincide with supersymmetric Israel-Wilson-Perjes type dilaton-axion solutions. In presence of an event horizon supersymmetry is broken. The temperature of the static black holes is constant, and their mass does not depend on it, so the heat capacity is zero. We investigate geodesics and wave propagation in these spacetimes and find superradiance in the rotating case. Because of the non-asymptotically flat nature of the geometry, certain modes are reflected from infinity, in particular, all superradiant modes are confined. Thi...

  14. Moulting Black Holes

    CERN Document Server

    Bena, Iosif; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2011-01-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no b...

  15. Attractors in Black

    CERN Document Server

    Bellucci, S; Marrani, A

    2008-01-01

    We review recent results in the study of attractor horizon geometries (with non-vanishing Bekenstein-Hawking entropy) of dyonic extremal d=4 black holes in supergravity. We focus on N=2, d=4 ungauged supergravity coupled to a number n_{V} of Abelian vector multiplets, outlining the fundamentals of the special Kaehler geometry of the vector multiplets' scalar manifold (of complex dimension n_{V}), and studying the 1/2-BPS attractors, as well as the non-BPS (non-supersymmetric) ones with non-vanishing central charge. For symmetric special Kaehler geometries, we present the complete classification of the orbits in the symplectic representation of the classical U-duality group (spanned by the black hole charge configuration supporting the attractors), as well as of the moduli spaces of non-BPS attractors (spanned by the scalars which are not stabilized at the black hole event horizon). Finally, we report on an analogous classification for N>2-extended, d=4 ungauged supergravities, in which also the 1/N-BPS attrac...

  16. Slowly balding black holes

    CERN Document Server

    Lyutikov, Maxim

    2011-01-01

    The "no hair" theorem, a key result in General Relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the "no hair" theorem is not formally applicable for black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes $N_B = e \\Phi_\\infty /(\\pi c \\hbar)$, where $\\Phi_\\infty \\approx 2 \\pi^2 B_{NS} R_{NS}^3 /(P_{\\rm NS} c)$ is the initial magnetic flux through the hemisphere...

  17. Black hole's quantum levels

    CERN Document Server

    Corda, Christian

    2012-01-01

    By introducing a black hole's effective temperature, which takes into account both of the non-strictly thermal and non-strictly continuous characters of Hawking radiation, we recently re-analyzed black hole's quasi-normal modes and interpreted them naturally in terms of quantum levels for emissions of particles. After a careful review of previous results, in this work we improve such an analysis by removing an approximation that we implicitly used in our previous work and by obtaining the corrected expressions for the formulas of the horizon's area quantization and the number of quanta of area and hence also for Bekenstein-Hawking entropy, its sub-leading corrections and the number of micro-states, i.e. quantities which are fundamental to realize unitary quantum gravity theory, like functions of the quantum overtone number e (emission) and, in turn,of the black hole's quantum excited level. Another approximation concerning the maximum value of e is also corrected. We also consider quasi-normal modes in terms ...

  18. Black Holes and Beyond

    CERN Document Server

    Mathur, Samir D

    2012-01-01

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome `remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a `fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates ...

  19. Black silicon solar cells with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....

  20. Non-Abelian magnetic black strings versus black holes

    Science.gov (United States)

    Mazharimousavi, S. Habib; Halilsoy, M.

    2016-05-01

    We present d+1 -dimensional pure magnetic Yang-Mills (YM) black strings (or 1-branes) induced by the d -dimensional Einstein-Yang-Mills-Dilaton black holes. The Born-Infeld version of the YM field makes our starting point which goes to the standard YM field through a limiting procedure. The lifting from black holes to black strings (with less number of fields) is done by adding an extra, compact coordinate. This amounts to the change of horizon topology from S^{d-2} to a product structure. Our black string in 5 dimensions is a rather special one, with uniform Hawking temperature and non-asymptotically flat structure. As the YM charge becomes large the string gets thinner to tend into a breaking point and transform into a 4-dimensional black hole.

  1. Black Holes with Skyrme Hair

    CERN Document Server

    Shiiki, N; Shiiki, Noriko; Sawado, Nobuyuki

    2005-01-01

    This paper is intended to give a review of the recent developments on black holes with Skyrme hair. The Einstein-Skyrme system is known to possess black hole solutions with Skyrme hair. The spherically symmetric black hole skyrmion with B=1 was the first discovered counter example of the no-hair conjecture for black holes. Recently we found the B=2 axially symmetric black hole skyrmion. In this system, the black hole at the center of the skyrmion absorbs the baryon number partially, leaving fractional charge outside the horizon. Therefore the baryon number is no longer conserved. We examine the B=1, 2 black hole solutions in detail in this paper. The model has a natural extension to the gauged version which can describe monopole black hole skyrmions. Callan and Witten discussed the monopole catalysis of proton decay within the Skyrme model. We apply the idea to the Einstein-Maxwell-Skyrme system and obtain monopole black hole skyrmions. Remarkably there exist multi-black hole skyrmion solutions in which the g...

  2. Titanium dioxide-cellulose hybrid nanocomposite and its glucose biosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Maniruzzaman, Mohammad; Jang, Sang-Dong [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of); Kim, Jaehwan, E-mail: jaehwan@inha.ac.kr [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of)

    2012-06-25

    Highlights: Black-Right-Pointing-Pointer An organic-inorganic hybrid nanocomposite was fabricated by blending TiO{sub 2} nanoparticles and cellulose solution. Black-Right-Pointing-Pointer The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO{sub 2}. Black-Right-Pointing-Pointer Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. Black-Right-Pointing-Pointer Linear response of the glucose biosensor was obtained in the range of 1-10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO{sub 2})-cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO{sub 2} nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO{sub 2}-cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO{sub 2}-cellulose hybrid nanocomposite via covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1-10 mM. This study demonstrates that TiO{sub 2}-cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  3. How Black Are Black Hole Candidates?

    CERN Document Server

    Robertson, S L; Robertson, Stanley L.; Leiter, Darryl J.

    2002-01-01

    In previous work we found that many of the spectral properties of x-ray binaries, including both galactic black hole candiates (GBHC) and neutron stars, were consistent with the existence of intrinsically magnetized central objects. Here we review and extend the observational evidence for the existence of intrinsically magnetized GBHC and show that their existence is consistent with a new class of solutions of the Einstein field equations of General Relativity. These solutions are based on a strict adherence to the Principle of Equivalence, which prevents the time-like geodesics of physical matter from becoming null on trapped surfaces of infinite red shift. The new solutions emerge from the fact that the structure and radiation transfer properties of the energy-momentum tensor on the right hand side of the Einstein field equations must have a form that is consistent with this Principle of Equivalence requirement. In this context, we show that the Einstein field equations allow the existence of highly red shi...

  4. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2015-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  5. Preparation and photocatalytic properties of hybrid core-shell reusable CoFe{sub 2}O{sub 4}-ZnO nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, A. [Department of Physics, University of Memphis, Memphis, TN 38152 (United States); Mishra, S.R., E-mail: srmishra@memphis.edu [Department of Physics, University of Memphis, Memphis, TN 38152 (United States); Gupta, R.; Ghosh, K. [Department of Physics, Materials Science, and Astronomy, Missouri State University, Springfield, MO (United States)

    2012-08-15

    Magnetically separable and reusable core-shell CoFe{sub 2}O{sub 4}-ZnO photocatalyst nanospheres were prepared by the hydrothermal synthesis technique using glucose derived carbon nanospheres as the template. The morphology and the phase of core-shell hybrid structure of CoFe{sub 2}O{sub 4}-ZnO were assessed via TEM, SEM and XRD. The magnetic composite showed high UV photocatalytic activity for the degradation of methylene blue in water. The photocatalytic activity was found to be ZnO shell thickness dependent. Thicker ZnO shells lead to higher rate of photocatalytic activity. Hybrid nanospheres recovered using an external magnetic field demonstrated good repeatability of photocatalytic activity. These results promise the reusability of the hybrid nanospheres for photocatalytic activity. - Highlights: Black-Right-Pointing-Pointer Synthesis of novel hybrid magnetic-ZnO core-shell composite nanospheres. Black-Right-Pointing-Pointer High photocatalytic activity of hybrid nanospheres was noted as compared to that of pure ZnO nanoparticles. Black-Right-Pointing-Pointer The hybrid nanospheres could be easily retrieved using an external magnet for repeated use. Black-Right-Pointing-Pointer Repeated use of hybrid nanospheres did not show any degradation in the photocatalytic activity. Black-Right-Pointing-Pointer The photocatalysis rate was observed to be ZnO shell thickness dependent.

  6. Black Swan Tropical Cyclones

    Science.gov (United States)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

  7. Geometry of black hole spacetimes

    CERN Document Server

    Andersson, Lars; Blue, Pieter

    2016-01-01

    These notes, based on lectures given at the summer school on Asymptotic Analysis in General Relativity, collect material on the Einstein equations, the geometry of black hole spacetimes, and the analysis of fields on black hole backgrounds. The Kerr model of a rotating black hole in vacuum is expected to be unique and stable. The problem of proving these fundamental facts provides the background for the material presented in these notes. Among the many topics which are relevant for the uniqueness and stability problems are the theory of fields on black hole spacetimes, in particular for gravitational perturbations of the Kerr black hole, and more generally, the study of nonlinear field equations in the presence of trapping. The study of these questions requires tools from several different fields, including Lorentzian geometry, hyperbolic differential equations and spin geometry, which are all relevant to the black hole stability problem.

  8. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  9. Hybrid intelligent engineering systems

    CERN Document Server

    Jain, L C; Adelaide, Australia University of

    1997-01-01

    This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

  10. A Hybrid Imagination

    DEFF Research Database (Denmark)

    Jamison, Andrew; Christensen, Steen Hyldgaard; Botin, Lars

    contexts, or sites, for mixing scientific knowledge and technical skills from different fields and social domains into new combinations, thus fostering what the authors term a “hybrid imagination”. Such a hybrid imagination is especially important today, as a way to counter the competitive and commercial...

  11. Hybrid trajectory spaces

    NARCIS (Netherlands)

    Collins, P.J.

    2005-01-01

    In this paper, we present a general framework for describing and studying hybrid systems. We represent the trajectories of the system as functions on a hybrid time domain, and the system itself by its trajectory space, which is the set of all possible trajectories. The trajectory space is given a na

  12. Editorial: Hybrid Systems

    DEFF Research Database (Denmark)

    Olderog, Ernst-Rüdiger; Ravn, Anders Peter

    2007-01-01

    An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005.......An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005....

  13. Origin of supermassive black holes

    OpenAIRE

    Dokuchaev, V. I.; Eroshenko, Yu. N.; Rubin, S G

    2007-01-01

    The origin of supermassive black holes in the galactic nuclei is quite uncertain in spite of extensive set of observational data. We review the known scenarios of galactic and cosmological formation of supermassive black holes. The common drawback of galactic scenarios is a lack of time and shortage of matter supply for building the supermassive black holes in all galaxies by means of accretion and merging. The cosmological scenarios are only fragmentarily developed but propose and pretend to...

  14. Sarcoid granuloma on black tattoo.

    Science.gov (United States)

    Morales-Callaghan, Ana María; Aguilar-Bernier, Miguel; Martínez-García, Gerardo; Miranda-Romero, Alberto

    2006-11-01

    We report the case of a patient with a black and turquoise tattoo who developed sarcoid granulomas on the areas of black pigment. Patch tests showed a positive reaction to nickel, cobalt, and cadmium; spectrophotometric analysis of the black pigment revealed the presence of nickel and cobalt among other metals. Although the pathogenesis of sarcoid granulomas is unknown, it seems that a delayed type hypersensitivity reaction is one of the mechanisms involved.

  15. The Gifted Black Child: Problems and Promise.

    Science.gov (United States)

    Howard, John R.

    In this paper, it is noted that there are three reasons for studying the black gifted child. First, black destiny has in part been shaped by talented blacks--for example, Malcolm X and Martin Luther King. Second, the black gifted are a minority within a minority. The gifted black female, subject to sexism, is even more of a minority. Third,…

  16. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  17. Hybrid propulsion technology program

    Science.gov (United States)

    1990-01-01

    Technology was identified which will enable application of hybrid propulsion to manned and unmanned space launch vehicles. Two design concepts are proposed. The first is a hybrid propulsion system using the classical method of regression (classical hybrid) resulting from the flow of oxidizer across a fuel grain surface. The second system uses a self-sustaining gas generator (gas generator hybrid) to produce a fuel rich exhaust that was mixed with oxidizer in a separate combustor. Both systems offer cost and reliability improvement over the existing solid rocket booster and proposed liquid boosters. The designs were evaluated using life cycle cost and reliability. The program consisted of: (1) identification and evaluation of candidate oxidizers and fuels; (2) preliminary evaluation of booster design concepts; (3) preparation of a detailed point design including life cycle costs and reliability analyses; (4) identification of those hybrid specific technologies needing improvement; and (5) preperation of a technology acquisition plan and large scale demonstration plan.

  18. How black holes saved relativity

    Science.gov (United States)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  19. Thermodynamics of Accelerating Black Holes.

    Science.gov (United States)

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  20. Black holes and the multiverse

    Science.gov (United States)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  1. Thermodynamics of Accelerating Black Holes

    CERN Document Server

    Appels, Michael; Kubiznak, David

    2016-01-01

    We address a long-standing problem of describing the thermodynamics of a charged accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon -- even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability and phase structure of these black holes.

  2. Thermodynamics of Accelerating Black Holes

    Science.gov (United States)

    Appels, Michael; Gregory, Ruth; KubizÅák, David

    2016-09-01

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon—even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  3. Black monazite from Taiwan

    Science.gov (United States)

    Matzko, J.J.; Overstreet, W.C.

    1977-01-01

    Two forms of detrital monazite are known in offshore bars in southwestern Taiwan: a yellow-green to colorless form and an unusual but abundant pelletlike form, generally black but also colored gray or brown. These black pellets, which are about 160 by 200 microns in size, are composed of fine-grained monazite crystals from 2 to 20 microns in size. The pellets are associated with highly variable amounts of discrete grains of detrital quartz, rutile, amphibole, tourmaline, and other minerals. Intergrown with the monazite are quartz, a cerium oxide mineral, chlorite, sulfides, and other minerals. Opaqueness of the pelletlike monazite is due principally to the cryptocrystalline nature of part of the monazite; only a small part of the opaqueness can be attributed to opaque inclusions. The black pelletlike monazite lacks thorium and has a high content of europium. In this respect, as in color, shape, size, and inclusions, the pelletlike monazite differs from the yellow-green detrital monazite. Despite the fact that they occur together in the littoral placers, they appear to have had different origins. The yellow-green monazite originated as an accessory mineral in plutonic rocks and has accumulated at the coast through erosion and transport. The origin of the pelletlike monazite is as yet unknown, but it is here inferred that it originated in unconsolidated coastal plain sediments through migration of cerium from the detrital monazite during weathering, and of the intermediate weight mobile rare earths from clay minerals during diagenesis. Possibly these pelletlike grains are detrital particles formed through erosion and transport from originally larger aggregates cemented by diagenetic monazite.

  4. Observing braneworld black holes

    CERN Document Server

    Gregory, R; Beckwith, K; Done, C; Gregory, Ruth; Whisker, Richard; Beckwith, Kris; Done, Chris

    2004-01-01

    Spacetime in the vicinity of an event horizon can be probed using observations which explore the dynamics of the accretion disc. Many high energy theories of gravity lead to modifications of the near horizon regime, potentially providing a testing ground for these theories. In this paper, we explore the impact of braneworld gravity on this region by formulating a method of deriving the general behaviour of the as yet unknown braneworld black hole solution. We use simple bounds to constrain the solution close to the horizon.

  5. Magnonic Black Holes.

    Science.gov (United States)

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  6. Thermal BEC Black Holes

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-10-01

    Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

  7. Magnonic Black Holes

    Science.gov (United States)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  8. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, C; Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.p, E-mail: orfeu@cosmos.ist.utl.p, E-mail: ncdias@mail.telepac.p, E-mail: joao.prata@mail.telepac.p [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)

    2010-04-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, {eta}. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  9. Black hole accretion discs

    OpenAIRE

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. ou...

  10. Artificial black holes

    CERN Document Server

    Visser, Matt; Volovik, Grigory E

    2009-01-01

    Physicists are pondering on the possibility of simulating black holes in the laboratory by means of various "analog models". These analog models, typically based on condensed matter physics, can be used to help us understand general relativity (Einstein's gravity); conversely, abstract techniques developed in general relativity can sometimes be used to help us understand certain aspects of condensed matter physics. This book contains 13 chapters - written by experts in general relativity, particle physics, and condensed matter physics - that explore various aspects of this two-way traffic.

  11. Self-assembled hybrid films of phosphotungstic acid and aminoalkoxysilanes on SiO{sub 2}/Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Adriano L. [Universidade de Sao Paulo (USP), Instituto de Quimica de Sao Carlos, P.O. Box 780, 13560-970, Sao Carlos, Sao Paulo (Brazil); Marques, Lygia A.; Eberlin, Marcos N. [Universidade Estadual de Campinas (UNICAMP), Instituto de Quimica, Laboratorio Thomson de Espectrometria de Massas, 13083-970, Campinas, Sao Paulo (Brazil); Nascente, Pedro A.P. [Universidade Federal de Sao Carlos (UFSCar), Departamento de Engenharia de Materiais, 13565-905, Sao Carlos, Sao Paulo (Brazil); Herrmann, Paulo S.P. [Empresa Brasileira de Pesquisa Agropecuaria, Embrapa Instrumentacao Agropecuaria, Laboratorio Nacional de Nanotecnologia para o Agronegocio, 13560-970, P.O.Box 741, Sao Carlos, Sao Paulo (Brazil); Leite, Fabio L. [Universidade Federal de Sao Carlos (UFSCar), Campus de Sorocaba, P. O. Box 3031, 18052-780, Sorocaba, Sao Paulo (Brazil); Rodrigues-Filho, Ubirajara P., E-mail: uprf@iqsc.usp.br [Universidade de Sao Paulo (USP), Instituto de Quimica de Sao Carlos, P.O. Box 780, 13560-970, Sao Carlos, Sao Paulo (Brazil)

    2012-02-29

    The present paper describes the influence of the chemical structure of two aminoalkoxysilanes: 3-aminopropyltriethoxysilane (APTS) and N-(3-(trimethoxysilyl)-propyl)-ethylenediamine (TSPEN) on the morphology of thin layer hybrid films with phosphotungstic acid (HPW), a Keggin heteropolyanion. X-ray photoelectron spectroscopy analyses indicated that both silane films showed protonated amine species interacting with the heteropolyanion by electrostatic forces as well as the presence of secondary carbamate anions. The hybrid films have different surface morphology according to atomic force microscopy analyses. The hybrid film with TSPEN forms flatter surfaces than the hybrid film with APTS. This effect is ascribed to higher flexibility and chelating ability of the TSPEN on adsorbed molecules. Ultrasonication effect on surface morphology of the hybrid film with APTS plays a fundamental role on surface roughness delivering enough energy to promote surface diffusion of the HPW heteropolyanions. This diffusion results in agglomerate formation, which corroborates with the assumption of electrostatic bonding between the HPW heteropolyanions and the protonated amine surface. These hybrid films could be used for electrochemical sensor design or to build photochromic and electrochromic multilayers. - Highlights: Black-Right-Pointing-Pointer Formation of phosphotungstate-aminosilylated surfaces. Black-Right-Pointing-Pointer Dependence of the surface roughness on the aminosilane structure. Black-Right-Pointing-Pointer Phosphotungstic acid chelation by N-(3-(trimethoxysilyl)-propyl)-ethylenediamine. Black-Right-Pointing-Pointer Ultrasonic promotion of clustering of phosphotungstic acid.

  12. Growing Up Black: A Black Literature Unit For Schools

    Science.gov (United States)

    Massenburg, Doris O.; Applebury, Bruce C.

    1971-01-01

    This literature-based unit is intended to examine the prevalent black moods, conflicts, alienations and disillusionments which accompany the present era. Literature selections include works by both black and white writers. At the end of the unit, the student will be able to realize the man, from what literature has stamped as substantial accounts…

  13. Black German identities : validating the multidimensional inventory of black identity

    NARCIS (Netherlands)

    Wandert, T.; Ochsmann, R.; Brug, P.; Chybicka, A.; Lacassagne, M.F.; Verkuyten, M.J.A.M.

    2009-01-01

    This study examines the reliability and validity of a German version of the Multidimensional Inventory of Black Identity (MIBI) in a sample of 170 Black Germans. The internal consistencies of all subscales are at least moderate. The factorial structure of the MIBI, as assessed by principal component

  14. Black Interpretation, Black American Literature, and Grey Audiences.

    Science.gov (United States)

    Washington, Earl M.

    1981-01-01

    Defines and illustrates language techniques used by Black authors writing to and for Blacks in the 1960s and 1970s. Suggests how language and theme barriers of such literature might be overcome in a contemporary integrated oral interpretation classroom. (PD)

  15. Surfing a Black Hole

    Science.gov (United States)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  16. The Black of Strei – a Swine Population on the Verge of Extinction in Banat

    Directory of Open Access Journals (Sweden)

    Marcel Matiuti

    2011-05-01

    Full Text Available The Black of Strei swine was declared to be extinct in 1974, but research conducted in 2008-2010 proved that there are still 61 specimens (Black of Strei proper and hybrids in the Hatzeg county and in the Lugoj area. Body measurements have been made in the case of those specimens and they showed that the specimens are a morphoproductive type. The local people appreciate the Black of Strei especially for its fat and bard which are very dry and used in order to obtain the traditional food products in the area. Prolificacy of sows farrowing is an 8 piglets per gestation. This breed is best kept in organic farms. The Black of Strei females are usually cross-bred with wildboar (Sus scrofa ferus males, the hybrids’ meat being very appreciated.

  17. Area spectrum of slowly rotating black holes

    OpenAIRE

    2010-01-01

    We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.

  18. Black holes in an expanding universe.

    Science.gov (United States)

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-02

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 black hole temperature.

  19. Astrophysical Black Holes in the Physical Universe

    CERN Document Server

    Zhang, Shuang-Nan

    2010-01-01

    In this chapter I focus on asking and answering the following questions: (1) What is a black hole? Answer: There are three types of black holes, namely mathematical black holes, physical black holes and astrophysical black holes. An astrophysical black hole, with mass distributed within its event horizon but not concentrated at the singularity point, is not a mathematical black hole. (2) Can astrophysical black holes be formed in the physical universe? Answer: Yes, at least this can be done with gravitational collapse. (3) How can we prove that what we call astrophysical black holes are really black holes? Answer: Finding direct evidence of event horizon is not the way to go. Instead I propose five criteria which meet the highest standard for recognizing new discoveries in experimental physics and observational astronomy. (4) Do we have sufficient evidence to claim the existence of astrophysical black holes in the physical universe? Answer: Yes, astrophysical black holes have been found at least in some galac...

  20. Thermal BEC black holes

    CERN Document Server

    Casadio, Roberto; Micu, Octavian; Orlandi, Alessio

    2015-01-01

    We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. An attractive self-interaction is needed for bound states to form, so that (approximately) one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The HWF is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a...

  1. Twistors and Black Holes

    CERN Document Server

    Neitzke, A; Vandoren, S; Neitzke, Andrew; Pioline, Boris; Vandoren, Stefan

    2007-01-01

    Motivated by black hole physics in N=2, D=4 supergravity, we study the geometry of quaternionic-Kahler manifolds M obtained by the c-map construction from projective special Kahler manifolds M_s. Improving on earlier treatments, we compute the Kahler potentials on the twistor space Z and Swann space S in the complex coordinates adapted to the Heisenberg symmetries. The results bear a simple relation to the Hesse potential \\Sigma of the special Kahler manifold M_s, and hence to the Bekenstein-Hawking entropy for BPS black holes. We explicitly construct the ``covariant c-map'' and the ``twistor map'', which relate real coordinates on M x CP^1 (resp. M x R^4/Z_2) to complex coordinates on Z (resp. S). As applications, we solve for the general BPS geodesic motion on M, and provide explicit integral formulae for the quaternionic Penrose transform relating elements of H^1(Z,O(-k)) to massless fields on M annihilated by first or second order differential operators. Finally, we compute the exact radial wave function ...

  2. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  3. Black hairy tongue syndrome.

    Science.gov (United States)

    Gurvits, Grigoriy E; Tan, Amy

    2014-08-21

    Black hairy tongue (BHT) is a benign medical condition characterized by elongated filiform lingual papillae with typical carpet-like appearance of the dorsum of the tongue. Its prevalence varies geographically, typically ranging from 0.6% to 11.3%. Known predisposing factors include smoking, excessive coffee/black tea consumption, poor oral hygiene, trigeminal neuralgia, general debilitation, xerostomia, and medication use. Clinical presentation varies but is typically asymptomatic, although aesthetic concerns are common. Differential diagnosis includes pseudo-BHT, acanthosis nigricans, oral hairy leukoplakia, pigmented fungiform papillae of the tongue, and congenital melanocytic/melanotic nevi/macules. Clinical diagnosis relies on visual observation, detailed history taking, and occasionally microscopic evaluation. Treatment involves identification and discontinuation of the offending agent, modifications of chronic predisposing factors, patient's re-assurance to the benign nature of the condition, and maintenance of adequate oral hygiene with gentle debridement to promote desquamation. Complications of BHT (burning mouth syndrome, halitosis, nausea, gagging, dysgeusia) typically respond to therapy. Prognosis is excellent with treatment of underlying medical conditions. BHT remains an important medical condition which may result in additional burden on the patient and health care system and requires appropriate prevention, recognition and treatment.

  4. Virtual Black Holes

    CERN Document Server

    Hawking, Stephen William

    1996-01-01

    One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of S^2\\times S^2 and K3 bubbles. Comparison with the instantons for pair creation of black holes shows that the S^2\\times S^2 bubbles can be interpreted as closed loops of virtual black holes. It is shown that scattering in such topological fluctuations leads to loss of quantum coherence, or in other words, to a superscattering matrix \\ that does not factorise into an S matrix and its adjoint. This loss of quantum coherence is very small at low energies for everything except scalar fields, leading to the prediction that we may never observe the Higgs particle. Another possible observational consequence may be that the \\theta angle of QCD is zero without having to invoke the problematical existence of a light axion. The pic...

  5. Hybrid electric vehicles TOPTEC

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-06-21

    This one-day TOPTEC session began with an overview of hybrid electric vehicle technology. Updates were given on alternative types of energy storage, APU control for low emissions, simulation programs, and industry and government activities. The keynote speech was about battery technology, a key element to the success of hybrids. The TOPEC concluded with a panel discussion on the mission of hybrid electric vehicles, with a perspective from industry and government experts from United States and Canada on their view of the role of this technology.

  6. Hybrid systems with constraints

    CERN Document Server

    Daafouz, Jamal; Sigalotti, Mario

    2013-01-01

    Control theory is the main subject of this title, in particular analysis and control design for hybrid dynamic systems.The notion of hybrid systems offers a strong theoretical and unified framework to cope with the modeling, analysis and control design of systems where both continuous and discrete dynamics interact. The theory of hybrid systems has been the subject of intensive research over the last decade and a large number of diverse and challenging problems have been investigated. Nevertheless, many important mathematical problems remain open.This book is dedicated mainly to

  7. Hybrid Bloch Brane

    CERN Document Server

    Bazeia, D; Losano, L

    2016-01-01

    This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios.

  8. Hybrid Bloch brane

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Lima, Elisama E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

    2017-02-15

    This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios. (orig.)

  9. Hybrid silicon evanescent devices

    Directory of Open Access Journals (Sweden)

    Alexander W. Fang

    2007-07-01

    Full Text Available Si photonics as an integration platform has recently been a focus of optoelectronics research because of the promise of low-cost manufacturing based on the ubiquitous electronics fabrication infrastructure. The key challenge for Si photonic systems is the realization of compact, electrically driven optical gain elements. We review our recent developments in hybrid Si evanescent devices. We have demonstrated electrically pumped lasers, amplifiers, and photodetectors that can provide a low-cost, scalable solution for hybrid integration on a Si platform by using a novel hybrid waveguide architecture, consisting of III-V quantum wells bonded to Si waveguides.

  10. Nonlinear Electrodynamics and black holes

    CERN Document Server

    Breton, N; Breton, Nora; Garcia-Salcedo, Ricardo

    2007-01-01

    It is addressed the issue of black holes with nonlinear electromagnetic field, focussing mainly in the Born-Infeld case. The main features of these systems are described, for instance, geodesics, energy conditions, thermodynamics and isolated horizon aspects. Also are revised some black hole solutions of alternative nonlinear electrodynamics and its inconveniences.

  11. ATLAS simulated black hole event

    CERN Multimedia

    Pequenão, J

    2008-01-01

    The simulated collision event shown is viewed along the beampipe. The event is one in which a microscopic-black-hole was produced in the collision of two protons (not shown). The microscopic-black-hole decayed immediately into many particles. The colors of the tracks show different types of particles emerging from the collision (at the center).

  12. Black Component of Dark Matter

    Directory of Open Access Journals (Sweden)

    A. V. Grobov

    2014-01-01

    Full Text Available A mechanism of primordial black hole formation with specific mass spectrum is discussed. It is shown that these black holes could contribute to the energy density of dark matter. Our approach is elaborated in the framework of universal extra dimensions.

  13. Educating Black Males with Dyslexia

    Science.gov (United States)

    Robinson, Shawn Anthony

    2013-01-01

    Much of the scholarship on Black males in the educational literature focuses on the achievement gap; their underrepresentation in gifted and advanced placement programs; their overrepresentation in special education programs and their high rates of school suspensions and expulsions. Although overrepresented in special education, Black males with…

  14. Black-Hole Mass Measurements

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2004-01-01

    The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....

  15. Black raspberry: Korean vs. American

    Science.gov (United States)

    This fact sheet shows Korean black raspberry (Rubus coreanus) fruit, flower, and leaf features that distinguish them from their Rubus relatives, black raspberry (R. occidentalis) native to America. Common names with fruit characteristics, including berry size and pigment fingerprints, are summarized...

  16. Black holes in brane worlds

    Indian Academy of Sciences (India)

    M S Modgil; S Panda; S Sengupta

    2004-03-01

    A Kerr metric describing a rotating black hole is obtained on the three brane in a five-dimensional Randall-Sundrum brane world by considering a rotating five-dimensional black string in the bulk. We examine the causal structure of this space-time through the geodesic equations.

  17. Introduction: Teaching Black Lives Matter

    Directory of Open Access Journals (Sweden)

    Paula Austin

    2016-11-01

    Full Text Available An introduction to Radical Teacher, Issue 106: Teaching Black Lives Matter. This issue brings together a diverse collection of articles exploring educator’s responses, strategies, and stories on how #BlackLivesMatter has informed their teaching practice, the content of their courses, and their personal relationship to colleagues, family, friends, and self.

  18. Teaching Black History after Obama

    Science.gov (United States)

    Sotiropoulos, Karen

    2017-01-01

    This article is a reflection on the teaching of black history after the Obama presidency and at the dawn of the Trump era. It is both an analysis of the state of the academic field and a primer on how to integrate the past few decades of scholarship in black history broadly across standard K-12 curriculum. It demonstrates the importance of…

  19. Black Dialect: Myth and Reality.

    Science.gov (United States)

    Gantt, Walter

    Based on transcribed conversations with black children in kindergarten and the intermediate grades, a study was devised to determine whether black urban children from lower socioeconomic areas speak a systematic, consistent form of nonstandard English, and if so, to provide a syntactical analysis of the dialect of nonstandard speakers. Speech…

  20. Black holes and the multiverse

    CERN Document Server

    Garriga, Jaume; Zhang, Jun

    2015-01-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive blac...

  1. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

  2. String-corrected black holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, Veronika E. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Maloney, Alexander [SLAC and Department of Physics, Stanford University, Stanford, CA 94309 (United States); Rangamani, Mukund [Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2005-05-01

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect - the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive{exclamation_point} The magnitude of this effect is related to the size of the compactification manifold.

  3. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, V.

    2005-01-12

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

  4. When Charged Black Holes Merge

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  5. Characterization of R genes involved in resistance to Cherry leaf roll virus in paradox hybrids

    Science.gov (United States)

    A single dominant ‘R’ gene (clrvR), in black walnuts (Juglans hindsii) or ‘paradox’ hybrids (J. hindsii x J. regia) confers resistance to Cherry leaf roll virus (CLRV), the causal agent of blackline disease. The identification and cloning of the ‘R’ gene is expected to aid the walnut breeding progra...

  6. Hybride Nanocomposites aus Ruß, Nanoclay und NR/BR

    NARCIS (Netherlands)

    Sapkota, B.; Poikelispää, M.; Das, A.; Dierkes, W.K.; Vuorinen, J.

    2013-01-01

    The influence of partial replacement of carbon black (CB) by nanoclay on the curing kinetics of natural rubber/butadiene rubber-based hybrid nanocomposites was studied. The successive replacement of CB by organically modified nanoclays significantly influenced the curing behaviour of the compound: T

  7. Activity of wild-type and hybrid Bacillus thuringiensis delta-endotoxins against Agrotis ipsilon

    NARCIS (Netherlands)

    Maagd, de R.A.; Weemen-Hendriks, M.; Molthoff, J.W.; Naimov, S.

    2003-01-01

    Twelve Cry1 and two Cry9 ?-endotoxins fromBacillus thuringiensis were tested for their activity against black cutworm (Agrotis ipsilon).A. ipsilon was not susceptible to many toxins, but three toxins had significant activity. Cry9Ca was the most toxic, followed by Cry1Aa and Cry1Fb. Hybrids between

  8. Chaotic mixer improves microarray hybridization.

    Science.gov (United States)

    McQuain, Mark K; Seale, Kevin; Peek, Joel; Fisher, Timothy S; Levy, Shawn; Stremler, Mark A; Haselton, Frederick R

    2004-02-15

    Hybridization is an important aspect of microarray experimental design which influences array signal levels and the repeatability of data within an array and across different arrays. Current methods typically require 24h and use target inefficiently. In these studies, we compare hybridization signals obtained in conventional static hybridization, which depends on diffusional target delivery, with signals obtained in a dynamic hybridization chamber, which employs a fluid mixer based on chaotic advection theory to deliver targets across a conventional glass slide array. Microarrays were printed with a pattern of 102 identical probe spots containing a 65-mer oligonucleotide capture probe. Hybridization of a 725-bp fluorescently labeled target was used to measure average target hybridization levels, local signal-to-noise ratios, and array hybridization uniformity. Dynamic hybridization for 1h with 1 or 10ng of target DNA increased hybridization signal intensities approximately threefold over a 24-h static hybridization. Similarly, a 10- or 60-min dynamic hybridization of 10ng of target DNA increased hybridization signal intensities fourfold over a 24h static hybridization. In time course studies, static hybridization reached a maximum within 8 to 12h using either 1 or 10ng of target. In time course studies using the dynamic hybridization chamber, hybridization using 1ng of target increased to a maximum at 4h and that using 10ng of target did not vary over the time points tested. In comparison to static hybridization, dynamic hybridization reduced the signal-to-noise ratios threefold and reduced spot-to-spot variation twofold. Therefore, we conclude that dynamic hybridization based on a chaotic mixer design improves both the speed of hybridization and the maximum level of hybridization while increasing signal-to-noise ratios and reducing spot-to-spot variation.

  9. Are LIGO's Black Holes Made From Smaller Black Holes?

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    The recent successes of the Laser Interferometer Gravitational-Wave Observatory (LIGO) has raised hopes that several long-standing questions in black-hole physics will soon be answerable. Besides revealing how the black-hole binary pairs are built, could detections with LIGO also reveal how the black holes themselves form?Isolation or HierarchyThe first detection of gravitational waves, GW150914, was surprising for a number of reasons. One unexpected result was the mass of the two black holes that LIGO saw merging: they were a whopping 29 and 36 solar masses.On the left of this schematic, two first-generation (direct-collapse) black holes form a merging binary. The right illustrates a second-generation hierarchical merger: each black hole in the final merging binary was formed by the merger of two smaller black holes. [Adapted fromGerosa et al., a simultaneously published paper that also explores the problem of hierarchical mergers and reaches similar conclusions]How do black holes of this size form? One possibility is that they form in isolation from the collapse of a single massive star. In an alternative model, they are created through the hierarchical merger of smaller black holes, gradually building up to the size we observed.A team of scientists led by Maya Fishbach (University of Chicago) suggests that we may soon be able to tell whether or not black holes observed by LIGO formed hierarchically. Fishbach and collaborators argue that hierarchical formation leaves a distinctive signature on the spins of the final black holes and that as soon as we have enough merger detections from LIGO, we can use spin measurements to statistically determine if LIGO black holes were formed hierarchically.Spins from Major MergersWhen two black holes merge, both their original spins and the angular momentum of the pair contribute to the spin of the final black hole that results. Fishbach and collaborators calculate the expected distribution of these final spins assuming that

  10. Hybrid polymer microspheres

    Science.gov (United States)

    Rembaum, A.

    1980-01-01

    Techniques have been successfully tested for bonding polymeric spheres, typically 0.1 micron in diameter, to spheres with diameter up to 100 microns. Hybrids are being developed as improved packing material for ion-exchange columns, filters, and separators.

  11. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  12. Hybrid photon detectors

    CERN Document Server

    D'Ambrosio, C

    2003-01-01

    Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron-hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array t...

  13. Functional hybrid materials

    National Research Council Canada - National Science Library

    Fahmi, Amir; Pietsch, Torsten; Mendoza, Cesar; Cheval, Nicolas

    2009-01-01

    .... This paper describes our group's achievements towards the development of multifunctional nanostructures via self-assembly of hybrid systems based on the block copolymer PS-b-P4VP and inorganic nanoparticles (NPs...

  14. Hybrid Rocket Technology

    Directory of Open Access Journals (Sweden)

    Sankaran Venugopal

    2011-04-01

    Full Text Available With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems. Classical hybrids can be throttled for thrust tailoring, perform in-flight motor shutdown and restart. In classical hybrids, the fuel is stored in the form of a solid grain, requiring only half the feed system hardware of liquid bipropellant engines. The commonly used fuels are benign, nontoxic, and not hazardous to store and transport. Solid fuel grains are not highly susceptible to cracks, imperfections, and environmental temperature and are therefore safer to manufacture, store, transport, and use for launch. The status of development based on the experience of the last few decades indicating the maturity of the hybrid rocket technology is given in brief.Defence Science Journal, 2011, 61(3, pp.193-200, DOI:http://dx.doi.org/10.14429/dsj.61.518

  15. Nitrous Paraffin Hybrid Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nitrous Oxide Paraffin Hybrid engine (N2OP) is a proposed technology designed to provide small launch vehicles with high specific impulse, indefinitely storable...

  16. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  17. Complicated Contradictions Amid Black Feminism and Millennial Black Women Teachers Creating Curriculum for Black Girls

    Science.gov (United States)

    Nyachae, Tiffany M.

    2016-01-01

    Millennial Black women teachers wrestle with two simultaneous burdens: disrupting the racist and sexist status quo of schooling through curriculum, and employing tactics to survive school politics among their majority White women colleagues. This article describes how the "Sisters of Promise" (SOP) curriculum aligned with Black feminism…

  18. Complicated Contradictions Amid Black Feminism and Millennial Black Women Teachers Creating Curriculum for Black Girls

    Science.gov (United States)

    Nyachae, Tiffany M.

    2016-01-01

    Millennial Black women teachers wrestle with two simultaneous burdens: disrupting the racist and sexist status quo of schooling through curriculum, and employing tactics to survive school politics among their majority White women colleagues. This article describes how the "Sisters of Promise" (SOP) curriculum aligned with Black feminism…

  19. Hybrid Baryon Signatures

    CERN Document Server

    Page, P R

    2000-01-01

    We discuss whether a low-lying hybrid baryon should be defined as a three quark - gluon bound state or as three quarks moving on an excited adiabatic potential. We show that the latter definition becomes exact, not only for very heavy quarks, but also for specific dynamics. We review the literature on the signatures of hybrid baryons, with specific reference to strong hadronic decays, electromagnetic couplings, diffractive production and production in psi decay.

  20. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  1. Requirements for Hybrid Cosimulation

    Science.gov (United States)

    2014-08-16

    hybrid cosimulation version of the Functional Mockup Interface (FMI) standard. A cosimulation standard de nes interfaces that enable diverse simulation...cosimulation standards, and specifically provides guidance for development of a hybrid cosimulation version of the Functional Mockup Interface (FMI) standard...V. Peetz, and S. Wolf. The functional mockup interface for tool independent exchange of simulation models. In Proc. of the 8-th International

  2. Magnetic fields around black holes

    Science.gov (United States)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  3. Hybrid nanostructured drug carrier with tunable and controlled drug release

    Energy Technology Data Exchange (ETDEWEB)

    Depan, D.; Misra, R.D.K., E-mail: dmisra@louisiana.edu

    2012-08-01

    We describe here a transformative approach to synthesize a hybrid nanostructured drug carrier that exhibits the characteristics of controlled drug release. The synthesis of the nanohybrid architecture involved two steps. The first step involved direct crystallization of biocompatible copolymer along the long axis of the carbon nanotubes (CNTs), followed by the second step of attachment of drug molecule to the polymer via hydrogen bonding. The extraordinary inorganic-organic hybrid architecture exhibited high drug loading ability and is physically stable even under extreme conditions of acidic media and ultrasonic irradiation. The temperature and pH sensitive characteristics of the hybrid drug carrier and high drug loading ability merit its consideration as a promising carrier and utilization of the fundamental aspects used for synthesis of other promising drug carriers. The higher drug release response during the application of ultrasonic frequency is ascribed to a cavitation-type process in which the acoustic bubbles nucleate and collapse releasing the drug. Furthermore, the study underscores the potential of uniquely combining CNTs and biopolymers for drug delivery. - Graphical abstract: Block-copolymer crystallized on carbon nanotubes (CNTs). Nanohybrid drug carrier synthesized by attaching doxorubicin (DOX) to polymer crystallized CNTs. Crystallized polymer on CNTs provide mechanical stability. Triggered release of DOX. Highlights: Black-Right-Pointing-Pointer The novel synthesis of a hybrid nanostructured drug carrier is described. Black-Right-Pointing-Pointer The drug carrier exhibits high drug loading ability and is physically stable. Black-Right-Pointing-Pointer The high drug release is ascribed to a cavitation-type process.

  4. Black powder in gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

    2009-07-01

    Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

  5. Cosmic Intelligence and Black Holes

    CERN Document Server

    Lefebvre, V A; Lefebvre, Vladimir A.; Efremov, Yuri N.

    2000-01-01

    The paper is devoted to a new direction in SETI. After a general discussion of the field, the authors put forth the hypothesis that the black holes may serve as a physical substratum for intelligent beings. This hypothesis is based on four parallels between the brain-psyche system, on the one hand, and black holes, on the other. (1) The descriptions of brain and psyche, in the system brain-psyche, are complementary to each other, as descriptions by internal and external observers of a black hole in Susskind-t'Hooft's schema. (2) There is an aspect of the inner structure of a black hole in Kerr's model of the rotating black hole that is isomorphic to the structure of the human subjective domain in the psychological model of reflexion. (3) Both black holes and the brain-psyche system have a facet which can be represented using thermodynamic concepts. (4) The brain lends itself to a holographic description; as has been recently demonstrated by Susskind, black holes can also be described holographically. The auth...

  6. A nonsingular rotating black hole

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)

    2015-11-15

    The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

  7. Rotating black hole and quintessence

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag 54001, Durban (South Africa)

    2016-04-15

    We discuss spherically symmetric exact solutions of the Einstein equations for quintessential matter surrounding a black hole, which has an additional parameter (ω) due to the quintessential matter, apart from the mass (M). In turn, we employ the Newman-Janis complex transformation to this spherical quintessence black hole solution and present a rotating counterpart that is identified, for α = -e{sup 2} ≠ 0 and ω = 1/3, exactly as the Kerr-Newman black hole, and as the Kerr black hole when α = 0. Interestingly, for a given value of parameter ω, there exists a critical rotation parameter (a = a{sub E}), which corresponds to an extremal black hole with degenerate horizons, while for a < a{sub E}, it describes a nonextremal black hole with Cauchy and event horizons, and no black hole for a > a{sub E}. We find that the extremal value a{sub E} is also influenced by the parameter ω and so is the ergoregion. (orig.)

  8. The renaissance of black phosphorus

    Science.gov (United States)

    Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S.

    2015-04-01

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field.

  9. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Energy Regulatory Commission Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of Application for Partial Transfer of Licenses, and Soliciting Comments and Motions To Intervene On October 25, 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor)...

  10. myBlackBox: Blackbox Mobile Cloud Systems for Personalized Unusual Event Detection

    Science.gov (United States)

    Ahn, Junho; Han, Richard

    2016-01-01

    We demonstrate the feasibility of constructing a novel and practical real-world mobile cloud system, called myBlackBox, that efficiently fuses multimodal smartphone sensor data to identify and log unusual personal events in mobile users’ daily lives. The system incorporates a hybrid architectural design that combines unsupervised classification of audio, accelerometer and location data with supervised joint fusion classification to achieve high accuracy, customization, convenience and scalability. We show the feasibility of myBlackBox by implementing and evaluating this end-to-end system that combines Android smartphones with cloud servers, deployed for 15 users over a one-month period. PMID:27223292

  11. myBlackBox: Blackbox Mobile Cloud Systems for Personalized Unusual Event Detection.

    Science.gov (United States)

    Ahn, Junho; Han, Richard

    2016-05-23

    We demonstrate the feasibility of constructing a novel and practical real-world mobile cloud system, called myBlackBox, that efficiently fuses multimodal smartphone sensor data to identify and log unusual personal events in mobile users' daily lives. The system incorporates a hybrid architectural design that combines unsupervised classification of audio, accelerometer and location data with supervised joint fusion classification to achieve high accuracy, customization, convenience and scalability. We show the feasibility of myBlackBox by implementing and evaluating this end-to-end system that combines Android smartphones with cloud servers, deployed for 15 users over a one-month period.

  12. myBlackBox: Blackbox Mobile Cloud Systems for Personalized Unusual Event Detection

    Directory of Open Access Journals (Sweden)

    Junho Ahn

    2016-05-01

    Full Text Available We demonstrate the feasibility of constructing a novel and practical real-world mobile cloud system, called myBlackBox, that efficiently fuses multimodal smartphone sensor data to identify and log unusual personal events in mobile users’ daily lives. The system incorporates a hybrid architectural design that combines unsupervised classification of audio, accelerometer and location data with supervised joint fusion classification to achieve high accuracy, customization, convenience and scalability. We show the feasibility of myBlackBox by implementing and evaluating this end-to-end system that combines Android smartphones with cloud servers, deployed for 15 users over a one-month period.

  13. Can Black Hole Relax Unitarily?

    Science.gov (United States)

    Solodukhin, S. N.

    2005-03-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  14. Can Black Hole Relax Unitarily?

    OpenAIRE

    Solodukhin, Sergey N.

    2004-01-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the...

  15. Black holes and Higgs stability

    CERN Document Server

    Tetradis, Nikolaos

    2016-01-01

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  16. Black holes and Higgs stability

    Energy Technology Data Exchange (ETDEWEB)

    Tetradis, Nikolaos [Department of Physics, University of Athens,Zographou 157 84 (Greece); Physics Department, Theory Unit, CERN,CH-1211 Geneva 23 (Switzerland)

    2016-09-20

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  17. Can Black Hole Relax Unitarily?

    CERN Document Server

    Solodukhin, S N

    2004-01-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  18. Vacuum metastability with black holes

    Energy Technology Data Exchange (ETDEWEB)

    Burda, Philipp [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute, 31 Caroline Street North,Waterloo, ON, N2L 2Y5 (Canada); Moss, Ian G. annd [School of Mathematics and Statistics, Newcastle University,Newcastle Upon Tyne, NE1 7RU (United Kingdom)

    2015-08-24

    We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

  19. Static-Fluid Black Holes

    CERN Document Server

    Cho, Inyong

    2016-01-01

    We investigate black holes formed by static perfect fluid with $p=-\\rho/3$. These represent the black holes in $S_3$ and $H_3$ spatial geometries. There are three classes of black-hole solutions, two $S_3$ types and one $H_3$ type. The interesting solution is the one of $S_3$ type which possesses two singularities. The one is at the north pole behind the horizon, and the other is naked at the south pole. The observers, however, are free from falling to the naked singularity. There are also nonstatic cosmological solutions in $S_3$ and $H_3$, and a singular static solution in $H_3$.

  20. On regular rotating black holes

    Science.gov (United States)

    Torres, R.; Fayos, F.

    2017-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  1. Orbital resonances around black holes.

    Science.gov (United States)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  2. Quantum mechanics of black holes.

    Science.gov (United States)

    Witten, Edward

    2012-08-03

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  3. Black Holes: A Traveler's Guide

    Science.gov (United States)

    Pickover, Clifford A.

    1998-03-01

    BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.

  4. On regular rotating black holes

    CERN Document Server

    Torres, Ramon

    2016-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  5. Hunting black holes with Gaia

    Science.gov (United States)

    Mashian, Natalie; Loeb, Abraham

    2017-09-01

    We predict the number of black holes with stellar companions that are potentially detectable with Gaia astrometry over the course of its 5-yr mission. Our model estimates that nearly 2 × 105 astrometric binaries hosting black holes and stellar companions brighter than Gaia's detection threshold, G ∼ 20, should be discovered with 5σ sensitivity. Among these detectable binaries, systems with longer orbital periods are favoured, and black hole and stellar companion masses in the range MBH ∼ 6-10 M⊙ and M* ∼ 1-2 M⊙, respectively, are expected to dominate.

  6. The Black Hole Information Problem

    CERN Document Server

    Polchinski, Joseph

    2016-01-01

    The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas.

  7. Mobilizing Black America: Solutions to Black Health Problems

    Science.gov (United States)

    1993-04-01

    the most obese ethnic group in America. Too many black children are overweight because black adults feed them a steady diet of fatty and salty foods...start and elementary school children in the Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) program. EPSDT has been instrumental in...blood cholesterol, obesity , unhealthy diets, and smoking are the leading causes (major risk factors) of these killers. The underlying problems associated

  8. Black layers on historical architecture.

    Science.gov (United States)

    Toniolo, Lucia; Zerbi, Carlotta M; Bugini, Roberto

    2009-03-01

    The external surface of any building in urban polluted environment is unavoidably destined to be covered with layers that assume a grey to black colour and are generally called 'black crusts'. These, according to standard protocols and glossary, are deteriorated surface layers of stone material; they can have variable thickness, are hard and fragile and can detach spontaneously from the substrate, which, in general, is quite decayed. Plain visual examination may lead to consider 'black crusts' all similar, whilst only a careful diagnostic investigation can distinguish 'black crusts' and the consequences of their formation on stone substrates. In this paper, various black layers on marble are studied and compared and the morphological and compositional characteristics discussed according to the related mechanisms of formation. Differences between old (hundred years) and recent crusts (30 years) are investigated and pointed out. Samples of black crusts collected from the Milan Cathedral façade (Candoglia Marble) have been studied and compared with the careful and synergic employ of traditional techniques: optical (transmission and reflected VIS light) and electron microscopy, X-ray spectrometry and micro-Fourier transform infrared spectroscopy. Visual examination of loose fragments does not allow to point out outstanding differences amongst the various samples; black layers have similar main mineral components, gypsum and airborne particles, with different spatial distribution. The microscopic studies allowed to point out the porosity differences, the gypsum crystallisation habit, different amount of embedded particles, level and progress of marble decay. The observations lead to define three main types of black crusts: black crust deriving from marble sulphation, compact deposit and encrustation due to exogenic materials deposition. Black crusts show evidence of sulphation in progress, without a clear continuity solution between crust and marble; the lack of

  9. Flipping the Coin: Towards a Double-Faced Approach to Teaching Black Literature in Secondary English Classrooms

    Science.gov (United States)

    Price, Vincent

    2017-01-01

    Critiquing two approaches that English teachers use to teach Black, or African-American, literature in the secondary classroom--one that centralises races and the other that ignores it--this article proposes a hybrid approach that combines both. This double-faced approach recognises the culturally specific themes that give the text and the Black…

  10. Cryo-Etched Black Silicon for Use as Optical Black

    Science.gov (United States)

    Yee, Karl Y.; White, Victor E.; Mouroulis, Pantazis; Eastwood, Michael L.

    2011-01-01

    Stray light reflected from the surface of imaging spectrometer components in particular, the spectrometer slit degrade the image quality. A technique has been developed for rapid, uniform, and cost-effective black silicon formation based on inductively coupled plasma (ICP) etching at cryogenic temperatures. Recent measurements show less than 1-percent total reflectance from 350 2,500 nm of doped black silicon formed in this way, making it an excellent option for texturing of component surfaces for reduction of stray light. Oxygen combines with SF6 + Si etch byproducts to form a passivation layer atop the Si when the etch is performed at cryogenic temperatures. Excess flow of oxygen results in micromasking and the formation of black silicon. The process is repeatable and reliable, and provides control over etch depth and sidewall profile. Density of the needles can be controlled to some extent. Regions to be textured can be patterned lithographically. Adhesion is not an issue as the nanotips are part of the underlying substrate. This is in contrast to surface growth/deposition techniques such as carbon nanotubes (CNTs). The black Si surface is compatible with wet processing, including processing with solvents, the textured surface is completely inorganic, and it does not outgas. In radiometry applications, optical absorbers are often constructed using gold black or CNTs. This black silicon technology is an improvement for these types of applications.

  11. Graduating Black Males: A Generic Qualitative Study

    Science.gov (United States)

    Bell, Edward E.

    2014-01-01

    Black males face a difficult educational battle. Across America, graduation statistics for Black males are sobering. The purpose of this study was to explore why Black males drop out of school and to examine the current employment status of the study participants. The research took place in rural North Carolina. Fifteen Black American male high…

  12. Accretion, primordial black holes and standard cosmology

    Indian Academy of Sciences (India)

    B Nayak; P Singh

    2011-01-01

    Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes are the proper candidates for dark matter.

  13. The Repertoire of Black Popular Culture

    National Research Council Canada - National Science Library

    Nelson, Angela

    2009-01-01

    ... in the diaspora), of the black aesthetic (the distinctive cultural repertoires out of which popular representations were made), and of the black counternarratives we have struggled to voice" (28). Hall further declares that "good" black popular culture can pass the test of authenticity when the form or product refers to the black experience (his...

  14. The Core Journal Concept in Black Studies

    Science.gov (United States)

    Weissinger, Thomas

    2010-01-01

    Black Studies scholars have shown interest in the core journal concept. Indeed, the idea of core journals for the study of the Black experience has changed several times since 1940. While Black Studies scholars are citing Black Studies journals with frequency, they also cite traditional disciplinary journals a great deal of the time. However,…

  15. The Making of the Black Middle Class.

    Science.gov (United States)

    Collins, Sharon M.

    1983-01-01

    Examines Black occupational mobility and factors that have influenced the growth of the Black middle class since the 1960s. Argues that the Black middle class occupies a fragile market position because Black mobility depends on fluctuating government policy rather than on free market factors. (Author/MJL)

  16. Magnetic Black Holes Are Also Unstable

    CERN Document Server

    Kim, Sang Pyo

    2004-01-01

    Most black holes are known to be unstable to emitting Hawking radiation (in asymptotically flat spacetime). If the black holes are non-extreme, they have positive temperature and emit thermally. If they are extremal rotating black holes, they still spontaneously emit particles like gravitons and photons. If they are extremal electrically charged black holes, they are unstable to emitting electrons or positrons. The only exception would be extreme magnetically charged black holes if there do not exist any magnetic monopoles for them to emit. However, here we show that even in this case, vacuum polarization causes all magnetic black holes to be unstable to emitting smaller magnetic black holes.

  17. The Hybrids of Postmodernism

    Directory of Open Access Journals (Sweden)

    Dana BĂDULESCU

    2014-09-01

    Full Text Available Hybridization is a fundamental characteristic of postmodernism, included by Ihab Hassan in his “catena” of features. This paper looks into the hybrids of postmodernism, which are the result of migration, displacement and uprooting, the re-visitation of myths, folklore and legends, or projections of their author’s imagination. The hybrids used as examples here are drawn from several novels written by Salman Rushdie, especially The Satanic Verses, two short stories, one by Márquez and the other by Donald Barthelme, Borges’s Book of Imaginary Beings, Cărtărescu’s Encyclopaedia of Dragons and Michelle Cliff’s No Telephone to Heaven. Diverse as they may be, these hybrids emphasize a defining characteristic of postmodernism, which is its pluralism. I conclude that the hybrids of postmodernism are aesthetically or politically subversive. Besides, what makes them difficult to grasp is their unfixed and protean nature. They ask for high leaps of the imagination, a total suspension of disbelief and a complete surrender to the powerful seduction of imagination on the reader’s part.

  18. How objective is black hole entropy?

    CERN Document Server

    Lau, Y K

    1994-01-01

    The objectivity of black hole entropy is discussed in the particular case of a Schwarzchild black hole. Using Jaynes' maximum entropy formalism and Euclidean path integral evaluation of partition function, it is argued that in the semiclassical limit when the fluctutation of metric is neglected, the black hole entropy of a Schwarzchild black hole is equal to the maximal information entropy of an observer whose sole knowledge of the black hole is its mass. Black hole entropy becomes a measure of number of its internal mass eigenstates in accordance with the Boltzmann principle only in the limit of negligible relative mass fluctutation. {}From the information theoretic perspective, the example of a Schwarzchild black hole seems to suggest that black hole entropy is no different from ordinary thermodynamic entropy. It is a property of the experimental data of a black hole, rather than being an intrinsic physical property of a black hole itself independent of any observer. However, it is still weakly objective in...

  19. Black holes and quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Hooft, G. ' t, E-mail: g.thooft@uu.n [Institute for Theoretical Physics, Utrecht University and Spinoza Institute, P.O. Box 80.195, 3508 TD Utrecht (Netherlands)

    2010-07-15

    After a brief review of quantum black hole physics, it is shown how the dynamical properties of a quantum black hole may be deduced to a large extent from Standard Model Physics, extended to scales near the Planck length, and combined with results from perturbative quantum gravity. Together, these interactions generate a Hilbert space of states on the black hole horizon, which can be investigated, displaying interesting systematics by themselves. To make such approaches more powerful, a study is made of the black hole complementarity principle, from which one may deduce the existence of a hidden form of local conformal invariance. Finally, the question is raised whether the principles underlying Quantum Mechanics are to be sharpened in this domain of physics as well. There are intriguing possibilities.

  20. Black holes by analytic continuation

    CERN Document Server

    Amati, Daniele

    1997-01-01

    In the context of a two-dimensional exactly solvable model, the dynamics of quantum black holes is obtained by analytically continuing the description of the regime where no black hole is formed. The resulting spectrum of outgoing radiation departs from the one predicted by the Hawking model in the region where the outgoing modes arise from the horizon with Planck-order frequencies. This occurs early in the evaporation process, and the resulting physical picture is unconventional. The theory predicts that black holes will only radiate out an energy of Planck mass order, stabilizing after a transitory period. The continuation from a regime without black hole formation --accessible in the 1+1 gravity theory considered-- is implicit in an S matrix approach and provides in this way a possible solution to the problem of information loss.

  1. Kerr black hole thermodynamical fluctuations

    Science.gov (United States)

    Pavon, D.; Rubi, J. M.

    1985-04-01

    The near-equilibrium thermodynamical (TD) fluctuations of a massive rotating uncharged Kerr black hole immersed in a uniformly corotating radiation bath at its temperature are investigated theoretically, generalizing Schwarzschild-black-hole analysis of Pavon and Rubi(1983), based on Einstein fluctuation theory. The correlations for the energy and angular moment fluctuations and the second moments of the other TD parameters are obtained, and the generalized second law of black-hole TD and the Bekenstein (1975) interpretation of black-hole entropy are seen as functioning well in this case. A local-stability criterion and relation for TD equilibrium between the Kerr hole and its own radiation in the flat-space-time limit are derived, and a restriction between C and Lambda is deduced.

  2. Recoiling Black Holes in Quasars

    CERN Document Server

    Bonning, E W; Salviander, S

    2007-01-01

    Recent simulations of merging black holes with spin give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole can retain the inner part of its accretion disk, providing fuel for a continuing QSO phase lasting millions of years as the hole moves away from the galactic nucleus. One possible observational manifestation of a recoiling accretion disk is in QSO emission lines shifted in velocity from the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with broad emission lines substantially shifted relative to the narrow lines. We find no convincing evidence for recoiling black holes carrying accretion disks. We place an upper limit on the incidence of recoiling black holes in QSOs of 4% for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s line-of-sight velocity.

  3. Singularities Inside Hairy Black Holes

    OpenAIRE

    Gal'tsov, D. V.; Donets, E. E.; Zotov, M. Yu.

    1997-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  4. Singularities Inside Hairy Black Holes

    CERN Document Server

    Galtsov, D V; Zotov, M Yu

    1998-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  5. Formation of Supermassive Black Holes

    CERN Document Server

    Volonteri, Marta

    2010-01-01

    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.

  6. 'Black holes': escaping the void.

    Science.gov (United States)

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  7. Space, time, and black holes

    Energy Technology Data Exchange (ETDEWEB)

    Darling, D.

    1980-10-01

    A discussion of Einstein's General Relativity and how it can explain black holes is included. The key idea of general relativity being that gravitational forces are a direct outcome of local curvature of space-time. The more mass something has the deeper the depression or well it causes in space-time. Black holes are supermassive objects, hence their gravity well is so steep even light can't escape. The three properties associated with a black hole are mass angular momentum, and electric charge. Non-rotating, Schwarzchild, and rotating, Kerr, black holes are studied. A Kruskal-Szekeres diagram for each type is given and explained. (SC)

  8. Wire Jewelry/Black History.

    Science.gov (United States)

    Daniel, Robert A.; Robinson, Charles C.

    1984-01-01

    Described is a project which made the study of Black history more real to fifth graders by having them make wire jewelry, smaller versions of the ornate filigreed ironwork produced by slave blacksmiths. (RM)

  9. Black Liquid Solar Collector Demonstrator.

    Science.gov (United States)

    Weichman, F. L.; Austen, D. J.

    1979-01-01

    Describes the details of constructing, and use of, a solar collector. Uses a black liquid to absorb the energy, the thermosyphon effect to drive the liquid through the collector, and a floodlamp as a surrogate sun. (GA)

  10. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  11. Black hole information vs. locality

    CERN Document Server

    Itzhaki, N

    1996-01-01

    We discuss the limitations on space time measurement in Schwarzchild metric. We find that near the horizon the limitations on space time measurement are of the order of the black hole radius. We suggest that it indicates that a large mass black hole can not be described by means of local field theory even at macroscopic distances and that any attempt to describe black hole formation and evaporation by means of an effective local field theory will necessarily lead to information loss. We also present a new interpretation of the black hole entropy which leads to S=cA , where c is a constant of order 1 which does not depend on the number of fields.

  12. Braneworld Black Hole Gravitational Lensing

    Science.gov (United States)

    Liang, Jun

    2017-04-01

    A class of braneworld black holes, which I called as Bronnikov-Melnikov-Dehen (BMD) black holes, are studied as gravitational lenses. I obtain the deflection angle in the strong deflection limit, and further calculate the angular positions and magnifications of relativistic images as well as the time delay between different relativistic images. I also compare the results with those obtained for Schwarzschild and two braneworld black holes, i.e., the tidal Reissner-Nordström (R-N) and the Casadio-Fabbri-Mazzacurati (CFM) black holes. Supported by Natural Science Foundation of Education Department of Shannxi Provincial Government under Grant No. 15JK1077, and Doctorial Scientific Research Starting Fund of Shannxi University of Science and Technology under Grant No. BJ12-02

  13. The Black Hole Universe Model

    Science.gov (United States)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  14. Research on Hybrid Vehicle Drivetrain

    Science.gov (United States)

    Xie, Zhongzhi

    Hybrid cars as a solution to energy saving, emission reduction measures, have received widespread attention. Motor drive system as an important part of the hybrid vehicles as an important object of study. Based on the hybrid electric vehicle powertrain control system for permanent magnet synchronous motor as the object of study. Can be applied to hybrid car compares the characteristics of traction motors, chose permanent magnet synchronous Motors as drive motors for hybrid vehicles. Building applications in hybrid cars in MATLAB/Simulink simulation model of permanent-magnet synchronous motor speed control system and analysis of simulation results.

  15. Geometric inequalities for black holes

    CERN Document Server

    Dain, Sergio

    2014-01-01

    It is well known that the three parameters that characterize the Kerr black hole (mass, angular momentum and horizon area) satisfy several important inequalities. Remarkably, some of these inequalities remain valid also for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this article recent results in this subject are reviewed.

  16. Are Black Holes Elementary Particles?

    CERN Document Server

    Ha, Yuan K

    2009-01-01

    Quantum black holes are the smallest and heaviest conceivable elementary particles. They have a microscopic size but a macroscopic mass. Several fundamental types have been constructed with some remarkable properties. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox of ultra-high energy cosmic rays detected in Earth's atmosphere. They may also play a role as dark matter in cosmology.

  17. Tensor Network and Black Hole

    CERN Document Server

    Matsueda, Hiroaki; Hashizume, Yoichiro

    2012-01-01

    A tensor network formalism of thermofield dynamics is introduced. The formalism relates the original Hilbert space with its tilde space by a product of two copies of a tensor network. Then, their interface becomes an event horizon, and the logarithm of the tensor rank corresponds to the black hole entropy. Eventually, multiscale entanglement renormalization anzats (MERA) reproduces an AdS black hole at finite temperature. Our finding shows rich functionalities of MERA as efficient graphical representation of AdS/CFT correspondence.

  18. Cosmological Black Holes on Branes

    OpenAIRE

    Rogatko, Marek

    2003-01-01

    We examined analytically a cosmological black hole domain wall system. Using the C-metric construction we derived the metric for the spacetime describing an infinitely thin domain wall intersecting a cosmological black hole. We studied the behaviour of the scalar field describing a self-interacting cosmological domain wall and find the approximated solution valid for large distances. The thin wall approximation and the back raection problem were elaborated finding that the topological kink so...

  19. Regular black hole in three dimensions

    OpenAIRE

    Myung, Yun Soo; Yoon, Myungseok

    2008-01-01

    We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

  20. Regular black hole in three dimensions

    OpenAIRE

    Myung, Yun Soo; Yoon, Myungseok

    2008-01-01

    We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

  1. The Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to the extensive ab initio calculations of lattice QCD, the much large energy density available in the heavy-ion collisions at SPS and now at RHIC should be enough to create the quark-gluon plasma (QGP); a new state of matter in form plasma of free quarks and gluons. The new matter discovered at RHIC is a ''nearly perfect'' fluid rather than a plasma. The shear viscosity is too small. We should then ask about the theoretical and phenomenological consequences and why we simply assumed that the deconfined hadronic matter should be an ideal gas. Finally, I will address five questions; about the properties of the new phases at high temperatures and the orders of phase transitions. Before we clarify such questions, the QGP will remain a kind of black box. One sends a signal via new experiments or simulations and gets another one out if it. Then one try to explain what is going on. I will show that some promising ideas already have been suggested long time ago, but it seems that community didn't care. Is ...

  2. Black, White and Grey

    Directory of Open Access Journals (Sweden)

    Nasrin Nooshfar

    2011-05-01

    Full Text Available Background/Objective: Development of science and"nart achieved with saving independence, separation"nclassification and studying their details. The other hand"nis combination of these to create a new world with"nwide dimensions and take a place to human needs."nMaterials and Methods: Our attempt is to make"nhealth-care places pleasant and attractive for patients."nWe offer best services, but they are not comfortable"nand happy in these places. They are afraid of the staff,"nequipment and the environment. For this purpose"nwe mixed the brightness and darkness of radiologic"nimages with white and black photographs or paintings"ncomplementary to create analog artistic images that"ncould be converted to digital printing by DICOM"ninterfaces on hard copies."nConclusion: Fear, pictures a bad memory in the"npatient's mind forever. We mixed radiology and"nimaging with photography as a science and art mixture"nto conflict with these problems, it is more effective in"nchildren who are suffering from social and known"ndiseases and can not adapt themselves with their"nsituations. This could create a good memory between"nthe human body image and sentimental experience."nIn the literature, printed radiologic images were used"nas fine art on glass and paper, metal and flowers were"nemployed to mix.* *Wim Delvoye (born 1965 ,Wervik"nand Steven N.Meyers and Merille Raikes

  3. Black Hole Meiosis

    CERN Document Server

    Van Herck, Walter

    2009-01-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, arXiv:0810.4301. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the `chromosomes' of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as `crossing-over in the meiosis of a D-particle'. Our results improve on hep-th/0702012, provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity...

  4. Black hole meiosis

    Science.gov (United States)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  5. Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to extensive ab initio calculations of lattice QCD, the very large energy density available in heavy-ion collisions at SPS and now at RHIC must be sufficient to generate quark-gluon plasma (QGP), a new state of matter in the form of plasma of free quarks and gluons. The new state of matter discovered at RHIC seems to be perfect fluid rather than free plasma. Its shear viscosity is assumed to be almost zero. In this work, I first considered the theoretical and phenomenological consequences of this discovery and finally asked questions about the nature of phase transition and properties of matter. It is important to answer these questions, otherwise QGP will remain a kind of black box; one sends a signal via new experiments or simulations or models and gets another one from it. I will show that some promising ideas have already been suggested a long time ago. I will also suggest a new phase diagram with separated deconfinement and freeze-out boundaries and a mixed state of thermal quark matter and bub...

  6. How Black Holes Burn

    CERN Document Server

    Brustein, Ram

    2014-01-01

    We present a calculation of the rate of information release from a Schwarzschild BH. We have recently extended Hawking's theory of black hole (BH) evaporation to account for quantum fluctuations of the background geometry, as well as for back-reaction and time-dependence effects. Our main result has been a two-point function matrix for the radiation that consists of Hawking's thermal matrix plus off-diagonal corrections that are initially small and become more important as the evaporation proceeds. Here, we show that, if the phases and amplitudes of the radiation matrix are recorded over the lifetime of the BH, then the radiation purifies in a continuous way. We conjecture that our results establish the maximal rate at which information can be released from a semiclassical BH, to be contrasted with the minimal rate that was predicted by Page on the basis of generic unitarity arguments. When the phases of the radiation matrix are not tracked, we show that it purifies only parametrically close to the end of the...

  7. Intermediate-Mass Black Holes

    CERN Document Server

    Miller, M C

    2004-01-01

    The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (roughly 3-20 solar masses), which are produced by the core collapse of massive stars, and supermassive (millions to billions of solar masses), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with hundreds to thousands of solar masses. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work t...

  8. Evolution of supermassive black holes

    CERN Document Server

    Volonteri, M

    2006-01-01

    Supermassive black holes (SMBHs) are nowadays believed to reside in most local galaxies, and the available data show an empirical correlation between bulge luminosity - or stellar velocity dispersion - and black hole mass, suggesting a single mechanism for assembling black holes and forming spheroids in galaxy halos. The evidence is therefore in favour of a co-evolution between galaxies, black holes and quasars. In cold dark matter cosmogonies, small-mass subgalactic systems form first to merge later into larger and larger structures. In this paradigm galaxy halos experience multiple mergers during their lifetime. If every galaxy with a bulge hosts a SMBH in its center, and a local galaxy has been made up by multiple mergers, then a black hole binary is a natural evolutionary stage. The evolution of the supermassive black hole population clearly has to be investigated taking into account both the cosmological framework and the dynamical evolution of SMBHs and their hosts. The seeds of SMBHs have to be looked ...

  9. Bounds on Black Hole Spins

    CERN Document Server

    Daly, Ruth A

    2009-01-01

    Beam powers and black hole masses of 48 extended radio sources are combined to obtain lower bounds on the spins and magnetic field strengths of supermassive black holes. This is done in the context of the models of Blandford & Znajek (1977) (the 'BZ' model) and Meier (1999); a parameterization for bounds in the context of other models is suggested. The bounds obtained for very powerful classical double radio sources in the BZ model are consistent with black hole spins of order unity for sources at high redshift. The black hole spins are largest for the highest redshift sources and decrease for sources at lower redshift; the sources studied have redshifts between zero and two. Lower power radio sources associated with central dominant galaxies may have black hole spins that are significantly less than one. Combining this analysis with other results suggests that the maximum values of black hole spin associated with powerful radio galaxies decline from values of order unity at a redshift of 2 to values of o...

  10. for hybrid dynamical systems

    Directory of Open Access Journals (Sweden)

    Wassim M. Haddad

    2001-01-01

    Full Text Available In this paper we develop a unified dynamical systems framework for a general class of systems possessing left-continuous flows; that is, left-continuous dynamical systems. These systems are shown to generalize virtually all existing notions of dynamical systems and include hybrid, impulsive, and switching dynamical systems as special cases. Furthermore, we generalize dissipativity, passivity, and nonexpansivity theory to left-continuous dynamical systems. Specifically, the classical concepts of system storage functions and supply rates are extended to left-continuous dynamical systems providing a generalized hybrid system energy interpretation in terms of stored energy, dissipated energy over the continuous-time dynamics, and dissipated energy over the resetting events. Finally, the generalized dissipativity notions are used to develop general stability criteria for feedback interconnections of left-continuous dynamical systems. These results generalize the positivity and small gain theorems to the case of left-continuous, hybrid, and impulsive dynamical systems.

  11. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Rönnkö, M.; Ravn, Anders Peter; Sere, K.

    2003-01-01

    In this paper we investigate the use of action systems with differential actions in the specifcation of hybrid systems. As the main contribution we generalize the definition of a differential action, allowing the use of arbitrary relations over model variables and their time-derivatives in modell......In this paper we investigate the use of action systems with differential actions in the specifcation of hybrid systems. As the main contribution we generalize the definition of a differential action, allowing the use of arbitrary relations over model variables and their time...... parallel composition. Moreover, as the strength of the action system formalism is the support for stepwise development by refinement, we investigate refinement involving a differential action. We show that, due to the predicate transformer semantics, standard action refinement techniques apply also...... to the differential action, thus, allowing stepwise development of hybrid systems Udgivelsesdato: JAN 1...

  12. Conditional Hybrid Nonclassicality

    Science.gov (United States)

    Agudelo, E.; Sperling, J.; Costanzo, L. S.; Bellini, M.; Zavatta, A.; Vogel, W.

    2017-09-01

    We derive and implement a general method to characterize the nonclassicality in compound discrete- and continuous-variable systems. For this purpose, we introduce the operational notion of conditional hybrid nonclassicality which relates to the ability to produce a nonclassical continuous-variable state by projecting onto a general superposition of discrete-variable subsystem. We discuss the importance of this form of quantumness in connection with interfaces for quantum communication. To verify the conditional hybrid nonclassicality, a matrix version of a nonclassicality quasiprobability is derived and its sampling approach is formulated. We experimentally generate an entangled, hybrid Schrödinger cat state, using a coherent photon-addition process acting on two temporal modes, and we directly sample its nonclassicality quasiprobability matrix. The introduced conditional quantum effects are certified with high statistical significance.

  13. Porosity in hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, D.W.; Beaucage, G.; Loy, D. [Sandia National Labs., Albuquerque, NM (United States)

    1995-12-31

    Multicomponent, or hybrid composites are emerging as precursors to porous materials. Sacrifice of an ephemeral phase can be used to generate porosity, the nature of which depends on precursor structure. Retention of an organic constituent, on the other hand, can add desirable toughness to an otherwise brittle ceramic. We use small-angle x-ray and neutron scattering to examine porosity in both simple and hybrid materials. We find that microphase separation controls porosity in almost all systems studied. Pore distributions are controlled by the detailed bonding within and between phases as well as the flexibility of polymeric constituents. Thus hybridization opens new regions of pore distributions not available in simple systems. We look at several sacrificial concepts and show that it is possible to generate multimodal pore size distributions due to the complicated phase structure in the precursor.

  14. Photoproduction of Hybrid Mesons

    CERN Document Server

    Barnes, T

    1998-01-01

    In this contribution I discuss prospects for photoproducing hybrid mesons at CEBAF, based on recent model results and experimental indications of possible hybrids. One excellent opportunity appears to be a search for the I=1, JPC=2+-, neutral "(b2)o" hybrid in (a2 pi)o through diffractive photoproduction. Other notable possibilities accessible through pi+ or pio exchange photoproduction are I=1, JPC=1-+, charged "pi1+" in f1 pi+, (b1 pi)+ and (rho pi)+; piJ(1770)+ in f2 pi+ and (b1 pi)+; pi(1800)+ in f0 pi+, f2 pi+, omega rho+ and (rho pi)+; a1 in f1 pi+ and f2 pi+; and omega in (rho pi)o, omega eta and (K1 K)o.

  15. Smart hybrid rotary damper

    Science.gov (United States)

    Yang, C. S. Walter; DesRoches, Reginald

    2014-03-01

    This paper develops a smart hybrid rotary damper using a re-centering smart shape memory alloy (SMA) material as well as conventional energy-dissipating metallic plates that are easy to be replaced. The ends of the SMA and steel plates are inserted in the hinge. When the damper rotates, all the plates bend, providing energy dissipating and recentering characteristics. Such smart hybrid rotary dampers can be installed in structures to mitigate structural responses and to re-center automatically. The damaged energy-dissipating plates can be easily replaced promptly after an external excitation, reducing repair time and costs. An OpenSEES model of a smart hybrid rotary was established and calibrated to reproduce the realistic behavior measured from a full-scale experimental test. Furthermore, the seismic performance of a 3-story moment resisting model building with smart hybrid rotary dampers designed for downtown Los Angeles was also evaluated in the OpenSEES structural analysis software. Such a smart moment resisting frame exhibits perfect residual roof displacement, 0.006", extremely smaller than 18.04" for the conventional moment resisting frame subjected to a 2500 year return period ground motion for the downtown LA area (an amplified factor of 1.15 on Kobe earthquake). The smart hybrid rotary dampers are also applied into an eccentric braced steel frame, which combines a moment frame system and a bracing system. The results illustrate that adding smart hybrid rotaries in this braced system not only completely restores the building after an external excitation, but also significantly reduces peak interstory drifts.

  16. Highly photoluminescent and photostable CdSe quantum dot-nylon hybrid composites for efficient light conversion applications

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Ying; Riehle, Frank-Stefan [Freiburg Materials Research Centre (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg (Germany); Department of Microsystems Engineering (IMTEK), Georg Koehler Allee 103, University of Freiburg, D-79110 Freiburg (Germany); Nitschke, Roland [Life Imaging Center, Centre of Systems Biology, University of Freiburg Habsburgerstr. 49, D-79104 Freiburg (Germany); Centre for Biological Signalling Studies (BIOSS), University of Freiburg (Germany); Krueger, Michael, E-mail: michael.krueger@fmf.uni-freiburg.de [Freiburg Materials Research Centre (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg (Germany); Department of Microsystems Engineering (IMTEK), Georg Koehler Allee 103, University of Freiburg, D-79110 Freiburg (Germany)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer A novel in situ synthesis approach for highly luminescent CdSe core QDs-nylon hybrid materials. Black-Right-Pointing-Pointer Potential applications for light and energy conversion are demonstrated. Black-Right-Pointing-Pointer Three dimensional structures out of this hybrid material are available. - Abstract: Highly photoluminescent hexadecylamine (HDA) capped core CdSe quantum dots (QDs) with fluorescent quantum yields (QYs) up to 60% were synthesized using a hot injection method and directly incorporated into nylon polymer. For the incorporation of crude CdSe QDs into nylon a simple reproducible and upscalable one pot approach was developed without the need of further purification steps. The photoluminescence (PL) properties of the core QDs and the resulting QD-polymer hybrid composites were investigated and compared. Red emitting hybrid materials exhibit a QY of 60% with a high potential for applications in direct light and energy conversion. The hybrid materials could be successfully utilized as LED conversion layers. By avoiding exposure to oxygen the hybrid films can be kept for a month without detecting a significant decrease in luminescence. Various three dimensional structures are easily available opening doors for further applications such as novel materials for fluorescence standard development in laser scanning microscopy (LSM).

  17. Erratic Black Hole Regulates Itself

    Science.gov (United States)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  18. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  19. Hybrid Weyl semimetal

    Science.gov (United States)

    Li, Fei-Ye; Luo, Xi; Dai, Xi; Yu, Yue; Zhang, Fan; Chen, Gang

    2016-09-01

    We construct a tight-binding model realizing one pair of Weyl nodes and three distinct Weyl semimetals. In the type-I (type-II) Weyl semimetal, both nodes belong to type-I (type-II) Weyl nodes. In addition, there exists a third type, previously undiscovered and dubbed "hybrid Weyl semimetal", in which one Weyl node is of type I while the other is of type II. For the hybrid Weyl semimetal, we further demonstrate the bulk Fermi surfaces and the topologically protected surface states, analyze the unique Landau-level structure and quantum oscillation, and discuss the conditions for possible material realization.

  20. Toyota hybrid synergy drive

    Energy Technology Data Exchange (ETDEWEB)

    Gautschi, H.

    2008-07-01

    This presentation made at the Swiss 2008 research conference on traffic by Hannes Gautschi, director of service and training at the Toyota company in Switzerland, takes a look at Toyota's hybrid drive vehicles. The construction of the vehicles and their combined combustion engines and electric generators and drives is presented and the combined operation of these components is described. Braking and energy recovery are discussed. Figures on the performance, fuel consumption and CO{sub 2} output of the hybrid vehicles are compared with those of conventional vehicles.

  1. Toyota hybrid synergy drive

    Energy Technology Data Exchange (ETDEWEB)

    Gautschi, H.

    2008-07-01

    This presentation made at the Swiss 2008 research conference on traffic by Hannes Gautschi, director of service and training at the Toyota company in Switzerland, takes a look at Toyota's hybrid drive vehicles. The construction of the vehicles and their combined combustion engines and electric generators and drives is presented and the combined operation of these components is described. Braking and energy recovery are discussed. Figures on the performance, fuel consumption and CO{sub 2} output of the hybrid vehicles are compared with those of conventional vehicles.

  2. THERMALLY CLEAVABLE HYBRID MATERIALS

    Directory of Open Access Journals (Sweden)

    Constantin Gaina

    2011-12-01

    Full Text Available Thermally cleavable hybrid materials were prepared by the Diels-Alder cycloaddition reaction of poly(vinyl furfural to N phenylmaleimido-N’-(triethoxysilylpropylurea followed by the sol-gel condensation reaction of trietoxysilyl groups with water and acetic acid. Thermal and dynamic mechanical analysis, dielectric and FTIR spectroscopy were used to characterize the structure and properties of the composites. The size of the inorganic silica particles in the hybrid material varied dependent on the silica content. The DSC study of the prepared materials revealed that the cleavage process of the formed cycloadducts takes place at temperatures varying between 143-165°C and is an endothermic process.

  3. The hybrid BCI

    Directory of Open Access Journals (Sweden)

    Gert Pfurtscheller

    2010-04-01

    Full Text Available Nowadays, everybody knows what a hybrid car is. A hybrid car normally has 2 engines, its main purpose being to enhance energy efficiency and reduce CO2 output. Similarly, a typical hybrid brain-computer interface (BCI is also composed of 2 BCIs or at least one BCI and another system. Such a hybrid BCI, like any BCI, must fulfil the following four criteria: (i the device must rely on signals recorded directly from the brain; (ii there must be at least one recordable brain signal that the user can intentionally modulate to effect goal-directed behaviour; (iii real time processing; and (iv the user must obtain feedback. This paper introduces some hybrid BCIs which have already been published or are currently in development or validation, and some concepts for future work. The BCIs described classify 2 EEG patterns: One is the event-related (desynchronisation (ERD, ERS of sensorimotor rhythms, and the other is the steady-state visual evoked potential (SSVEP. The hybrid BCI can either have more than one input whereby the inputs are typically processed simultaneously or operate 2 systems sequentially, whereby the first system can act as a “brain switch”. In the case of self-paced operation of a SSVEP-based hand orthosis control with an motor imagery-based switch it was possible to reduce the rate of false positives during resting periods by about 50% compared to the SSVEP BCI alone. It is shown that such a brain switch can also rely on hemodynamic changes measured through near-infrared spectroscopy (NIRS. Another interesting approach is a hybrid BCI with simultaneous operations of ERD- and SSVEP-based BCIs. Here it is important to prove the existing promising offline simulation results with online experiments. Hybrid BCIs can also use one brain signal and another input. Such an additional input can be a physiological signal like the heart rate but also a signal from an external device like, an eye gaze control system.

  4. Biomass in monospecific and mixed stands of eucalyptus and black wattle and corn in an agroforestry system

    Directory of Open Access Journals (Sweden)

    Márcio Viera

    2011-06-01

    Full Text Available This study aimed at quantifying the production and distribution of aboveground biomass from the plants in monospecific and mixed stands of eucalyptus (hybrid E. urophylla x E. grandis and black wattle (Acacia mearnsii and, of corn (Zea mays in agrosilvicultural systems. The biomass evaluation (leaf, branch, bark and wood from the forest species at 6 and 18 months of age were performed at the treatments: 100E (100% of eucalyptus + corn; - 100A (100% of black wattle + corn; - 50E:50A (50% of eucalyptus + 50% of black wattle + corn. The corn biomass evaluation (stem, leaves, straw, cob and grains was performed at treatments 100E; 100A; 50E:50A; 75E:25A (75% of eucalyptus + 25% of black wattle + corn; and - 25E:75A (25% of eucalyptus + 75% of black wattle + corn. The biomass production from eucalyptus and from the black wattle, in both monospecific and mixed planting, did not differ in any of the assessed ages but, when evaluated by plants compartments, it was verified an interspecific competitive interaction from the eucalyptus on the black wattle, reducing the formation of crown biomass. The total production of corn biomass in agrosilvicutural systems with eucalyptus and with black wattle in monospecific or mixed plantings did not differ in the studied treatments.

  5. The NINJA-2 project: Detecting and characterizing gravitational waveforms modelled using numerical binary black hole simulations

    CERN Document Server

    :,; Abbott, B P; Abbott, R; Abbott, T; Abernathy, M R; Accadia, T; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Affeldt, C; Agathos, M; Aggarwal, N; Aguiar, O D; Ain, A; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Andersen, M; Anderson, R; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Austin, L; Aylott, B E; Babak, S; Baker, P T; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauchrowitz, J; Bauer, Th S; Behnke, B; Bejger, M; Beker, M G; Belczynski, C; Bell, A S; Bell, C; Bergmann, G; Bersanetti, D; Bertolini, A; Betzwieser, J; Beyersdorf, P T; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bloemen, S; Blom, M; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bond, C; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, Sukanta; Bosi, L; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Brooks, A F; Brown, D A; Brown, D D; Brückner, F; Buchman, S; Bulik, T; Bulten, H J; Buonanno, A; Burman, R; Buskulic, D; Buy, C; Cadonati, L; Cagnoli, G; Bustillo, J Calderón; Calloni, E; Camp, J B; Campsie, P; Cannon, K C; Canuel, B; Cao, J; Capano, C D; Carbognani, F; Carbone, L; Caride, S; Castiglia, A; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Celerier, C; Cella, G; Cepeda, C; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, X; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Chow, J; Christensen, N; Chu, Q; Chua, S S Y; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C; Colombini, M; Cominsky, L; Constancio, M; Conte, A; Cook, D; Corbitt, T R; Cordier, M; Cornish, N; Corpuz, A; Corsi, A; Costa, C A; Coughlin, M W; Coughlin, S; Coulon, J -P; Countryman, S; Couvares, P; Coward, D M; Cowart, M; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Dahl, K; Canton, T Dal; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dattilo, V; Daveloza, H; Davier, M; Davies, G S; Daw, E J; Day, R; Dayanga, T; Debreczeni, G; Degallaix, J; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; Díaz, M; Di Fiore, L; Di Lieto, A; Di Palma, I; Di Virgilio, A; Donath, A; Donovan, F; Dooley, K L; Doravari, S; Dossa, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Dwyer, S; Eberle, T; Edo, T; Edwards, M; Effler, A; Eggenstein, H; Ehrens, P; Eichholz, J; Eikenberry, S S; Endrőczi, G; Essick, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Feroz, F; Ferrante, I; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fisher, R P; Flaminio, R; Fournier, J -D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gair, J; Gammaitoni, L; Gaonkar, S; Garufi, F; Gehrels, N; Gemme, G; Genin, E; Gennai, A; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, C; Gleason, J; Goetz, E; Goetz, R; Gondan, L; González, G; Gordon, N; Gorodetsky, M L; Gossan, S; Goßler, S; Gouaty, R; Gräf, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Groot, P; Grote, H; Grover, K; Grunewald, S; Guidi, G M; Guido, C; Gushwa, K; Gustafson, E K; Gustafson, R; Hammer, D; Hammond, G; Hanke, M; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hart, M; Hartman, M T; Haster, C -J; Haughian, K; Heidmann, A; Heintze, M; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Heptonstall, A W; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Holt, K; Hooper, S; Hopkins, P; Hosken, D J; Hough, J; Howell, E J; Hu, Y; Hughey, B; Husa, S; Huttner, S H; Huynh, M; Huynh-Dinh, T; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Iyer, B R; Izumi, K; Jacobson, M; James, E; Jang, H; Jaranowski, P; Ji, Y; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalmus, P; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Karlen, J; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, H; Kawabe, K; Kawazoe, F; Kéfélian, F; Keiser, G M; Keitel, D; Kelley, D B; Kells, W; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, C; Kim, K; Kim, N; Kim, N G; Kim, Y -M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Koranda, S; Korth, W Z; Kowalska, I; Kozak, D B; Kremin, A; Kringel, V; Krishnan, B; Królak, A; Kuehn, G; Kumar, A; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Kwee, P; Landry, M; Lantz, B; Larson, S; Lasky, P D; Lawrie, C; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C -H; Lee, H K; Lee, H M; Lee, J; Leonardi, M; Leong, J R; Roux, A Le; Leroy, N; Letendre, N; Levin, Y; Levine, B; Lewis, J; Li, T G F; Libbrecht, K; Libson, A; Lin, A C; Littenberg, T B; Litvine, V; Lockerbie, N A; Lockett, V; Lodhia, D; Loew, K; Logue, J; Lombardi, A L; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J; Lubinski, M J; Lück, H; Luijten, E; Lundgren, A P; Lynch, R; Ma, Y; Macarthur, J; Macdonald, E P; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magana-Sandoval, F; Mageswaran, M; Maglione, C; Mailand, K; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Manca, G M; Mandel, I; Mandic, V; Mangano, V; Mangini, N; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Marque, J; Martelli, F; Martin, I W; Martin, R M; Martinelli, L; Martynov, D; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Matichard, F; Matone, L; Matzner, R A; Mavalvala, N; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McGuire, S C; McIntyre, G; McIver, J; McLin, K; Meacher, D; Meadors, G D; Mehmet, M; Meidam, J; Meinders, M; Melatos, A; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyers, P; Miao, H; Michel, C; Mikhailov, E E; Milano, L; Milde, S; Miller, J; Minenkov, Y; Mingarelli, C M F; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moe, B; Moesta, P; Mohan, M; Mohapatra, S R P; Moraru, D; Moreno, G; Morgado, N; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Mukherjee, S; Mullavey, A; Munch, J; Murphy, D; Murray, P G; Mytidis, A; Nagy, M F; Kumar, D Nanda; Nardecchia, I; Naticchioni, L; Nayak, R K; Necula, V; Nelemans, G; Neri, I; Neri, M; Newton, G; Nguyen, T; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Oh, J J; Oh, S H; Ohme, F; Oppermann, P; O'Reilly, B; O'Shaughnessy, R; Osthelder, C; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Palashov, O; Palomba, C; Pan, H; Pan, Y; Pankow, C; Paoletti, F; Paoletti, R; Papa, M A; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Pedraza, M; Penn, S; Perreca, A; Phelps, M; Pichot, M; Pickenpack, M; Piergiovanni, F; Pierro, V; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Poteomkin, A; Powell, J; Prasad, J; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Privitera, S; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Qin, J; Quetschke, V; Quintero, E; Quiroga, G; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; Rajalakshmi, G; Rakhmanov, M; Ramet, C; Ramirez, K; Rapagnani, P; Raymond, V; Re, V; Read, J; Reed, C M; Regimbau, T; Reid, S; Reitze, D H; Rhoades, E; Ricci, F; Riles, K; Robertson, N A; Robinet, F; Rocchi, A; Rodruck, M; Rolland, L; Rollins, J G; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Salemi, F; Sammut, L; Sandberg, V; Sanders, J R; Sannibale, V; Santiago-Prieto, I; Saracco, E; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Savage, R; Scheuer, J; Schilling, R; Schnabel, R; Schofield, R M S; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Shaddock, D; Shah, S; Shahriar, M S; Shaltev, M; Shapiro, B; Shawhan, P; Shoemaker, D H; Sidery, T L; Siellez, K; Siemens, X; Sigg, D; Simakov, D; Singer, A; Singer, L; Singh, R; Sintes, A M; Slagmolen, B J J; Slutsky, J; Smith, J R; Smith, M; Smith, R J E; Smith-Lefebvre, N D; Son, E J; Sorazu, B; Souradeep, T; Sperandio, L; Staley, A; Stebbins, J; Steinlechner, J; Steinlechner, S; Stephens, B C; Steplewski, S; Stevenson, S; Stone, R; Stops, D; Strain, K A; Straniero, N; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Susmithan, S; Sutton, P J; Swinkels, B; Tacca, M; Talukder, D; Tanner, D B; Tarabrin, S P; Taylor, R; ter Braack, A P M; Thirugnanasambandam, M P; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, V; Tokmakov, K V; Tomlinson, C; Toncelli, A; Tonelli, M; Torre, O; Torres, C V; Torrie, C I; Travasso, F; Traylor, G; Tse, M; Ugolini, D; Unnikrishnan, C S; Urban, A L; Urbanek, K; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; Brand, J F J van den; Broeck, C Van Den; van der Putten, S; van der Sluys, M V; van Heijningen, J; van Veggel, A A; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Verma, S S; Vetrano, F; Viceré, A; Vincent-Finley, R; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vousden, W D; Vyachanin, S P; Wade, A; Wade, L; Wade, M; Walker, M; Wallace, L; Wang, M; Wang, X; Ward, R L; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; Whitcomb, S E; White, D J; Whiting, B F; Wiesner, K; Wilkinson, C; Williams, K; Williams, L; Williams, R; Williams, T; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Worden, J; Yablon, J; Yakushin, I; Yamamoto, H; Yancey, C C; Yang, H; Yang, Z; Yoshida, S; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J -P; Zhang, Fan; Zhang, L; Zhao, C; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J; Boyle, M; Brügmann, B; Buchman, L T; Campanelli, M; Chu, T; Etienne, Z B; Hannam, M; Healy, J; Hinder, I; Kidder, L E; Laguna, P; Liu, Y T; London, L; Lousto, C O; Lovelace, G; MacDonald, I; Marronetti, P; Mösta, P; Müller, D; Mundim, B C; Nakano, H; Paschalidis, V; Pekowsky, L; Pollney, D; Pfeiffer, H P; Ponce, M; Pürrer, M; Reifenberger, G; Reisswig, C; Santamaría, L; Scheel, M A; Shapiro, S L; Shoemaker, D; Sopuerta, C F; Sperhake, U; Szilágyi, B; Taylor, N W; Tichy, W; Tsatsin, P; Zlochower, Y

    2014-01-01

    The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave astrophysics communities. The purpose of NINJA is to study the ability to detect gravitational waves emitted from merging binary black holes and recover their parameters with next-generation gravitational-wave observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete binary black hole hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a "blind injection challenge" similar to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid waveforms to two months of data recolored to predictions of Advanced LIGO and Advanced Virgo sensitivity curves during their first observing runs. The resulting data was analyzed by gravitational-wave detection algorithms and 6 of the waveforms were recovered w...

  6. Impact of light irradiation on black tea quality during withering.

    Science.gov (United States)

    Ai, Zeyi; Zhang, Beibei; Chen, Yuqiong; Yu, Zhi; Chen, Huacai; Ni, Dejiang

    2017-04-01

    Black tea manufacture usually involves the processes of withering, cutting, fermentation and drying. The aim of present study was to evaluate the effect of the relationship between the quality and withering with different light sources (ultraviolet, yellow, blue, purple, orange, red, cyan, green and white) an quality attribute of tea. The results indicated that the yellow, orange and red light withering significantly improved the aroma and taste, imparting the tea a sweet flavor and a fresh and mellow taste. Tea treated with yellow light was scored highest the sensory scores and showed the highest content in catechins, theaflavins, amino acids and aroma components, followed by the orange and red light treatments. The black tea withered with ultraviolet light showed a strong astringency, probably resulting from low contents of theaflavins, amino acids and soluble sugar. The green light irradiation remarkably damaged the aroma and taste of the tea, leading to a strong greenish flavor and an astringent taste, probably owing to the lowest contents of chemical compositions. No significant cumulative effect was found in the hybrid light withering treatments. Therefore, monochromatic yellow, orange and red lights were suggested for withering the black tea to improve its overall quality.

  7. A Mathematical Approach to Hybridization

    Science.gov (United States)

    Matthews, P. S. C.; Thompson, J. J.

    1975-01-01

    Presents an approach to hybridization which exploits the similarities between the algebra of wave functions and vectors. This method will account satisfactorily for the number of orbitals formed when applied to hybrids involving the s and p orbitals. (GS)

  8. myBlackBox: Blackbox Mobile Cloud Systems for Personalized Unusual Event Detection

    OpenAIRE

    Junho Ahn; Richard Han

    2016-01-01

    We demonstrate the feasibility of constructing a novel and practical real-world mobile cloud system, called myBlackBox, that efficiently fuses multimodal smartphone sensor data to identify and log unusual personal events in mobile users’ daily lives. The system incorporates a hybrid architectural design that combines unsupervised classification of audio, accelerometer and location data with supervised joint fusion classification to achieve high accuracy, customization, convenience and scalabi...

  9. Black hole quantum spectrum

    Science.gov (United States)

    Corda, Christian

    2013-12-01

    Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re-analysed BH quasi-normal modes (QNMs) and interpreted them naturally in terms of quantum levels. In this work we improve such an analysis removing some approximations that have been implicitly used in our previous works and obtaining the corrected expressions for the formulas of the horizon's area quantization and the number of quanta of area and hence also for Bekenstein-Hawking entropy, its subleading corrections and the number of micro-states, i.e. quantities which are fundamental to realize the underlying quantum gravity theory, like functions of the QNMs quantum "overtone" number n and, in turn, of the BH quantum excited level. An approximation concerning the maximum value of n is also corrected. On the other hand, our previous results were strictly corrected only for scalar and gravitational perturbations. Here we show that the discussion holds also for vector perturbations. The analysis is totally consistent with the general conviction that BHs result in highly excited states representing both the "hydrogen atom" and the "quasi-thermal emission" in quantum gravity. Our BH model is somewhat similar to the semi-classical Bohr's model of the structure of a hydrogen atom. The thermal approximation of previous results in the literature is consistent with the results in this paper. In principle, such results could also have important implications for the BH information paradox.

  10. Resource Letter BH-2: Black Holes

    CERN Document Server

    Gallo, Elena

    2008-01-01

    This resource letter is designed to guide students, educators, and researchers through (some of) the literature on black holes. Both the physics and astrophysics of black holes are discussed. Breadth has been emphasized over depth, and review articles over primary sources. We include resources ranging from non-technical discussions appropriate for broad audiences to technical reviews of current research. Topics addressed include classification of stationary solutions, perturbations and stability of black holes, numerical simulations, collisions, the production of gravity waves, black hole thermodynamics and Hawking radiation, quantum treatments of black holes, black holes in both higher and lower dimensions, and connections to nuclear and condensed matter physics. On the astronomical end, we also cover the physics of gas accretion onto black holes, relativistic jets, gravitationally red-shifted emission lines, evidence for stellar-mass black holes in binary systems and super-massive black holes at the centers...

  11. Hybrid Ventilation Air Flow Process

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols

    The scope of this annex is therefore to obtain better knowledge of the use of hybrid ventilation technologies. The annex focus on development of control strategies for hybrid ventilation, on development of methods to predict hybrid ventilation performance in office buildings and on implementation...

  12. (Hybrid) Baryons Symmetries and Masses

    CERN Document Server

    Page, P R

    1999-01-01

    We construct (hybrid) baryons in the flux-tube model of Isgur and Paton. In the limit of adiabatic quark motion, we build proper eigenstates of orbital angular momentum and construct the flavour, spin and J^P of hybrid baryons from the symmetries of the system. The lowest mass hybrid baryon is estimated at approximately 2 GeV.

  13. Improved hybrid rocket fuel

    Science.gov (United States)

    Dean, David L.

    1995-01-01

    McDonnell Douglas Aerospace, as part of its Independent R&D, has initiated development of a clean burning, high performance hybrid fuel for consideration as an alternative to the solid rocket thrust augmentation currently utilized by American space launch systems including Atlas, Delta, Pegasus, Space Shuttle, and Titan. It could also be used in single stage to orbit or as the only propulsion system in a new launch vehicle. Compared to solid propellants based on aluminum and ammonium perchlorate, this fuel is more environmentally benign in that it totally eliminates hydrogen chloride and aluminum oxide by products, producing only water, hydrogen, nitrogen, carbon oxides, and trace amounts of nitrogen oxides. Compared to other hybrid fuel formulations under development, this fuel is cheaper, denser, and faster burning. The specific impulse of this fuel is comparable to other hybrid fuels and is between that of solids and liquids. The fuel also requires less oxygen than similar hybrid fuels to produce maximum specific impulse, thus reducing oxygen delivery system requirements.

  14. Workshop on hybrid rice

    Institute of Scientific and Technical Information of China (English)

    TANZhijun

    1994-01-01

    FAO, in collaboration with FEDEARROZ in Colombia and EMBRAPA / CNPAF in Brail, organized a workshop on the Establishment of a Coorperative Research Network on Hybrid Rice in Latin America and the Caribbean held from Mar 16 to 18, 1994 at EMBRAPA/CNPAF in Brazil. Dr MAO Changxiang,

  15. Teelt van hybride wintertarwerassen

    NARCIS (Netherlands)

    Timmer, R.D.; Paauw, J.G.M.

    2003-01-01

    Om de mogelijkheden van de teelt van hybride wintertarwerassen onder Nederlandse omstandigheden in beeld te brengen zijn er van 2000-2002 proeven uitgevoerd op het PPO-proefbedrijf te Lelystad. In deze proeven zijn een 4-tal hybriderassen (Hybnos, Hyno-braba, Hyno-esta, Mercury) vergeleken met een s

  16. Organics go hybrid

    Science.gov (United States)

    Lanzani, Guglielmo; Petrozza, Annamaria; Caironi, Mario

    2017-01-01

    From displays to solar cells, the field of organic optoelectronics has come a long way over the past 50 years, but the realization of an electrically pumped organic laser remains elusive. The answer may lie with hybrid organic-inorganic materials called perovskites.

  17. Hybrid-secure MPC 

    DEFF Research Database (Denmark)

    Lucas, Christoph; Raub, Dominik; Maurer, Ueli

    2010-01-01

    Most protocols for distributed, fault-tolerant computation, or multi-party computation (MPC), provide security guarantees in an all-or-nothing fashion. In contrast, a hybrid-secure protocol provides different security guarantees depending on the set of corrupted parties and the computational powe...

  18. Indexical Hybrid Tense Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2012-01-01

    In this paper we explore the logic of now, yesterday, today and tomorrow by combining the semantic approach to indexicality pioneered by Hans Kamp [9] and refined by David Kaplan [10] with hybrid tense logic. We first introduce a special now nominal (our @now corresponds to Kamp’s original now...

  19. Nuclear hybrid energy infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek; Tawfik, Magdy S.

    2015-02-01

    The nuclear hybrid energy concept is becoming a reality for the US energy infrastructure where combinations of the various potential energy sources (nuclear, wind, solar, biomass, and so on) are integrated in a hybrid energy system. This paper focuses on challenges facing a hybrid system with a Small Modular Reactor at its core. The core of the paper will discuss efforts required to develop supervisory control center that collects data, supports decision-making, and serves as an information hub for supervisory control center. Such a center will also be a model for integrating future technologies and controls. In addition, advanced operations research, thermal cycle analysis, energy conversion analysis, control engineering, and human factors engineering will be part of the supervisory control center. Nuclear hybrid energy infrastructure would allow operators to optimize the cost of energy production by providing appropriate means of integrating different energy sources. The data needs to be stored, processed, analyzed, trended, and projected at right time to right operator to integrate different energy sources.

  20. Hybrid printed electronics

    NARCIS (Netherlands)

    Koetse, M.; Smits, E.; Rubingh, E.; Teunissen, P.; Kusters, R.; Abbel, R.; Brand, J. van den

    2016-01-01

    Although many electronic functionalities can be realized by printed or organic electronics, short-term marketable products often require robust, reproducible, and nondisturbing technologies. In this chapter we show how hybrid electronics, a combination of printed circuitry, thin-film electronics,

  1. Hybrid keyword search auctions

    KAUST Repository

    Goel, Ashish

    2009-01-01

    Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer\\'s estimate can use per-impression bids to correct the auctioneer\\'s prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The

  2. Massless black holes as black diholes and quadruholes

    CERN Document Server

    Ortín, Tomas

    1996-01-01

    Massless black holes can be understood as bound states of a (positive mass) extreme a=\\sqrt{3} black hole and a singular object with opposite ({\\it i.e.}~negative) mass with vanishing ADM (total) mass but non-vanishing gravitational field. Supersymmetric balance of forces is crucial for the existence of this kind of bound states and explains why the system does not move at the speed of light in spite of being massless. We also explain how supersymmetry allows for negative mass as long as it is never isolated but in bound states of total non-negative mass. The known massless black-hole solutions should then be considered particular cases of ``gravitational dipoles''. We also present ``gravitational quadrupoles'' and comment on the possible role of all these objects in string phase transitions.

  3. Could supermassive black holes be quintessential primordial black holes?

    CERN Document Server

    Bean, R; Bean, Rachel; Magueijo, Joao

    2002-01-01

    There is growing observational evidence for a population of supermassive black holes (SMBHs) in galactic bulges. We examine in detail the conditions under which these black holes must have originated from primordial black holes (PBHs). We consider the merging and accretion history experienced by SMBHs to find that, whereas it is possible that they were formed by purely astrophysical processes, this is unlikely and most probably a populations of primordial progenitors is necessary. We identify the mass distribution and comoving density of this population and then propose a cosmological scenario producing PBHs with the right properties. Although this is not essential we consider PBHs produced at the end of a period of inflation with a blue spectrum of fluctuations. We constrain the value of the spectral tilt in order to obtain the required PBH comoving density. We then assume that PBHs grow by accreting quintessence showing that their mass scales like the horizon mass while the quintessence field itself is scal...

  4. Prediction of genetic gain from selection indices for disease resistance in papaya hybrids

    Directory of Open Access Journals (Sweden)

    Marcelo Vivas

    2012-12-01

    Full Text Available In order to select superior hybrids for the concentration of favorable alleles for resistance to papaya black spot, powdery mildew and phoma spot, 67 hybrids were evaluated in two seasons, in 2007, in a randomized block design with two replications. Genetic gains were estimated from the selection indices of Smith & Hazel, Pesek & Baker, Williams, Mulamba & Mock, with selection intensity of 22.39%, corresponding to 15 hybrids. The index of Mulamba & Mock showed gains more suitable for the five traits assessed when it was used the criterion of economic weight tentatively assigned. Together, severity of black spot on leaves and on fruits, characteristics considered most relevant to the selection of resistant materials, expressed percentage gain of -44.15%. In addition, there were gains for other characteristics, with negative predicted selective percentage gain. The results showed that the index of Mulamba & Mock is the most efficient procedure for simultaneous selection of papaya hybrid resistant to black spot, powdery mildew and phoma spot.

  5. Preparation and antibacterial properties of hybrid-zirconia films with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Azocar, Ignacio, E-mail: manuel.azocar@usach.cl [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Vargas, Esteban [Facultad de Ingenieria, Departamento de Metalurgia, Universidad de Santiago de Chile, USACH (Chile); Duran, Nicole [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Arrieta, Abel [Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH (Chile); Gonzalez, Evelyn [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Facultad de Ingenieria, Departamento de Metalurgia, Universidad de Santiago de Chile, USACH (Chile); Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, USACH (Chile); Departamento de Quimica Farmacologica y Toxicologica, Facultad de Ciencias Quimicas, Universidad de Chile, Sergio Livingstone Polhammer 1007, Santiago (Chile); and others

    2012-11-15

    The antimicrobial effect of incorporating silver nanoparticles (AgNps) into zirconia matrix-polyether glycol was studied. AgNps of 4-6 nm in size were synthesized using the inverse micelles method, and different doses of metallic nanoparticles were incorporated into zirconia-polyether glycol mixtures during the ageing procedure. Atomic force microscopy (AFM) of the modified hybrid film showed a homogenous distribution of 20-80 nm diameter AgNps, indicating agglomeration of these structures during film modification; such agglomerations were greater when increasing the dosage of the colloidal system. The AgNps-hybrid films showed higher antimicrobial activity against Gram-positive bacteria than for Gram-negative bacteria. Hybrid films prepared with dioctyl sodium sulfosuccinate (AOT) stabilized AgNps presented enhanced antibacterial activity compared to that obtained through the addition of a high AgNO{sub 3} concentration (0.3 wt%). -- Graphical abstract: Atomic Force Micrographs, top and cross section view, showing silver nanoparticles embedded in a zirconia-polyether glycol hybrid film. Highlights: Black-Right-Pointing-Pointer Antibacterial activity of films (zirconia-polyether glycol) modified with silver nanoparticles. Black-Right-Pointing-Pointer Biofilm formation is prevented. Black-Right-Pointing-Pointer High sensibility against gram positive bacteria.

  6. Searching for numerically-simulated signals of black hole binaries with a phenomenological template family

    CERN Document Server

    Santamaria, Lucia; Whelan, John T

    2009-01-01

    Recent progress in numerical relativity now allows computation of the binary black hole merger, whereas post-Newtonian and perturbative techniques can be used to model the inspiral and ringdown phases. So far, most gravitational-wave searches have made use of various post-Newtonian-inspired templates to search for signals arising from the coalescence of compact binary objects. Ajith et al have produced hybrid waveforms for non-spinning binary black-hole systems which include the three stages of the coalescence process, and constructed from them phenomenological templates which capture the features of these waveforms in a parametrized form. As a first step towards extending the present inspiral searches to higher-mass binary black-hole systems, we have used these phenomenological waveforms in a search for numerically-simulated signals injected into synthetic LIGO data as part of the NINJA project.

  7. Dynamics of extremal black holes

    CERN Document Server

    Giddings, Steven B

    1992-01-01

    Particle scattering and radiation by a magnetically charged, dilatonic black hole is investigated near the extremal limit at which the mass is a constant times the charge. Near this limit a neighborhood of the horizon of the black hole is closely approximated by a trivial product of a two-dimensional black hole with a sphere. This is shown to imply that the scattering of long-wavelength particles can be described by a (previously analyzed) two-dimensional effective field theory, and is related to the formation/evaporation of two-dimensional black holes. The scattering proceeds via particle capture followed by Hawking re-emission, and naively appears to violate unitarity. However this conclusion can be altered when the effects of backreaction are included. Particle-hole scattering is discussed in the light of a recent analysis of the two-dimensional backreaction problem. It is argued that the quantum mechanical possibility of scattering off of extremal black holes implies the potential existence of additional ...

  8. Black Holes: The Membrane Viewpoint

    Science.gov (United States)

    Thorne, Kip S.

    Contents: I. Introduction: 1. Overview of the membrane viewpoint. 2. History of research on the membrane viewpoint. II. The 3+1 split of spacetime: 1. ZAMOs and the 3+1 split of the metric. 2. Gravitoelectric and gravitomagnetic fields. 3. 3+1 split of electrodynamics. III. Stretching the horizon and black-hole thermodynamics: 1. Macdonald's vibrating magnetic field problem. 2. Stretching the horizon. 3. The entropy of a black hole. 4. The thermodynamics and mechanics of a black hole. IV. Electrodynamics of the stretched horizon: 1. The laws of Gauss, Ampere, Ohm, and charge conservation. 2. Lorentz force and ohmic dissipation in the stretched horizon. V. Some electromagnetic model problems: 1. Charge separation in the stretched horizon. 2. Black hole as a resistor in an electric circuit. 3. Black hole as the rotor in an electric motor. 4. Rotating hole immersed in a time-independent, vacuum magnetic field. 5. Magnetized, rotating hole as a battery for an external circuit. VI. Astrophysical applications of the membrane formalism. VII. Conclusion.

  9. Information locking in black holes

    CERN Document Server

    Smolin, J; Smolin, John; Oppenheim, Jonathan

    2005-01-01

    The black hole information loss paradox has plagued physicists since Hawking's discovery that black holes evaporate. The calculation suggests that information thrown into a black hole is evaporated away as thermal radiation, and is destroyed: either the unitary laws of quantum theory break down, or we must modify the laws of general relativity. Here we show that one of the central presumptions of the debate is incorrect. Ensuring that information not escape during the semi-classical evaporation process does not require that all the information remain in the black hole until the final stages of evaporation. By taking into account recent results in quantum information theory, we find that the amount of information that must remain in the black hole until the final stages of evaporation can be very small, even though the amount of information which has already radiated away is negligible. Quantum effects mean that information need not be additive: a small number of quanta can lock a large amount of information, ...

  10. Silicon nanowires in polymer nanocomposites for photovoltaic hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Dkhil, S., E-mail: sadok.bendekhil@gmail.com [Laboratoire Physique des Materiaux, Structures et Proprietes Groupe Physique des Composants et Dispositifs Nanometriques, 7021 Jarzouna, Bizerte (Tunisia); Ingenierie des Materiaux Polymeres, IMP, UMR CNRS 5223, Universite Claude Bernard - Lyon 1, 15, boulevard Latarjet, 69622 Villeurbanne (France); Bourguiga, R. [Laboratoire Physique des Materiaux, Structures et Proprietes Groupe Physique des Composants et Dispositifs Nanometriques, 7021 Jarzouna, Bizerte (Tunisia); Davenas, J. [Ingenierie des Materiaux Polymeres, IMP, UMR CNRS 5223, Universite Claude Bernard - Lyon 1, 15, boulevard Latarjet, 69622 Villeurbanne (France); Cornu, D. [Institut Europeen des Membranes, UMR CNRS 5635, Ecole Nationale superieure de Chimie, Universite de Montpellier, 1919 route de Mende, F34000 Montpellier (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Hybrid solar cells based on blends of poly(N-vinylcarbazole) and silicon nanowires have been fabricated. Black-Right-Pointing-Pointer We have investigated the charge transfer between PVK and SiNWs by the way of the quenching of the PVK photoluminescence. Black-Right-Pointing-Pointer The relation between the morphology of the composite thin films and the charge transfer between SiNWs and PVK has been examined. Black-Right-Pointing-Pointer We have investigated the effects of SiNWs concentration on the photovoltaic characteristics leading to the optimization of a critical SiNWs concentration. - Abstract: Hybrid thin films combining the high optical absorption of a semiconducting polymer film and the electronic properties of silicon fillers have been investigated in the perspective of the development of low cost solar cells. Bulk heterojunction photovoltaic materials based on blends of a semiconductor polymer poly(N-vinylcarbazole) (PVK) as electron donor and silicon nanowires (SiNWs) as electron acceptor have been studied. Composite PVK/SiNWs films were cast from a common solvent mixture. UV-visible spectrometry and photoluminescence of the composites have been studied as a function of the SiNWs concentration. Photoluminescence spectroscopy (PL) shows the existence of a critical SiNWs concentration of about 10 wt % for PL quenching corresponding to the most efficient charge pair separation. The photovoltaic (PV) effect has been studied under illumination. The optimum open-circuit voltage V{sub oc} and short-circuit current density J{sub sc} are obtained for 10 wt % SiNWs whereas a degradation of these parameters is observed at higher SiNWs concentrations. These results are correlated to the formation of aggregates in the composite leading to recombination of the photogenerated charge pairs competing with the dissociation mechanism.

  11. Supersymmetric black holes in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Mohaupt, T. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street, Liverpool L69 7ZL (United Kingdom)

    2007-05-15

    We review recent developments concerning supersymmetric black holes in string theory. After a general introduction to the laws of black hole mechanics and to black hole entropy in string theory, we discuss black hole solutions in N=2 supergravity, special geometry, the black hole attractor equations and the underlying variational principle. Special attention is payed to the crucial role of higher derivative corrections. Finally we discuss black hole partition functions and their relation with the topological string, mainly from the supergravity perspective. We summarize the state of art and discuss various open questions and problems. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  12. Black di-ring and infinite nonuniqueness

    CERN Document Server

    Iguchi, H; Iguchi, Hideo; Mishima, Takashi

    2007-01-01

    We show that the $S^1$-rotating black rings can be superposed by the solution generating technique. We analyze the black di-ring solution for the simplest case of multiple rings. There exists an equilibrium black di-ring where the conical singularities are cured by the suitable choice of physical parameters. Also there are infinite numbers of black di-rings with the same mass and angular momentum. These di-rings can have two different continuous limits of single black rings. Therefore we can transform the fat black ring to the thin ring with the same mass and angular momentum by way of the di-ring solutions.

  13. Black holes a very short introduction

    CERN Document Server

    Blundell, Katherine

    2015-01-01

    Black holes are a constant source of fascination to many due to their mysterious nature. Black Holes: A Very Short Introduction addresses a variety of questions, including what a black hole actually is, how they are characterized and discovered, and what would happen if you came too close to one. It explains how black holes form and grow—by stealing material that belongs to stars—as well as how many there may be in the Universe. It also explores the large black holes found in the centres of galaxies, and how black holes power quasars and lie behind other spectacular phenomena in the cosmos.

  14. Astrophysical Black Holes: Evidence of a Horizon?

    Science.gov (United States)

    Colpi, Monica

    In this Lecture Note we first follow a short account of the history of the black hole hypothesis. We then review on the current status of the search for astrophysical black holes with particular attention to the black holes of stellar origin. Later, we highlight a series of observations that reveal the albeit indirect presence of supermassive black holes in galactic nuclei, with mention to forthcoming experiments aimed at testing directly the black hole hypothesis. We further focus on evidences of a black hole event horizon in cosmic sources.

  15. Increased electrochemical properties of ruthenium oxide and graphene/ruthenium oxide hybrid dispersed by polyvinylpyrrolidone

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yao; Zhang, Xiong; Zhang, Dacheng [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Ma, Yanwei, E-mail: ywma@mail.iee.ac.cn [Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A good dispersion of RuO{sub 2} and graphene/RuO{sub 2} is obtained by polyvinylpyrrolidone. Black-Right-Pointing-Pointer PVP as a dispersant also can prevent the formation of metal Ru in graphene/RuO{sub 2}. Black-Right-Pointing-Pointer The max capacitances of the hybrid and RuO{sub 2} reach 435 and 597 F g{sup -1} at 0.2 A g{sup -1}. Black-Right-Pointing-Pointer The hybrid shows the best rate capability of 39% at 50 A g{sup -1}. - Abstract: Ruthenium oxide has been prepared by a sol-gel method. Polyvinylpyrrolidone (PVP) as an excellent polymeric dispersant is adopted to prevent aggregation of ruthenium oxide. In order to enhance the rate capability of ruthenium oxide, graphene with residual oxygen functional groups as a 2D support has been merged into ruthenium oxide. These oxygen functional groups not only favor to form stable few layers of graphene colloids, but also offer the sites to anchor ruthenium oxide nanoparticles. X-ray diffraction infers that PVP can also hinder the partial formation of Ru by blocking the direct contact between the Ru{sup 3+} and the graphene in the sol-gel synthesis of the hybrids. The ruthenium oxide and the graphene/ruthenium oxide hybrids dispersed by PVP have superior electrochemical properties due to good dispersing and protecting ability of PVP. Especially, the hybrids using PVP exhibit the best rate capability, indicating that the composites possess an advanced structure of combining sheets and particles in nano-scale.

  16. Ants exhibit asymmetric hybridization in a mosaic hybrid zone.

    Science.gov (United States)

    Purcell, Jessica; Zahnd, Sacha; Athanasiades, Anouk; Türler, Rebecca; Chapuisat, Michel; Brelsford, Alan

    2016-10-01

    Research on hybridization between species provides unparalleled insights into the pre- and postzygotic isolating mechanisms that drive speciation. In social organisms, colony-level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping-by-sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single-queen and multiple-queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects.

  17. Fluoroscence in situ hybridization of chicken intestinal samples with bacterial rRNA targeted oligonucleotide probes

    DEFF Research Database (Denmark)

    Olsen, Katja Nyholm; Francesch, M.; Christensen, Henrik

    2006-01-01

    The objective was to develop a fast and accurate molecular method for the quantification of the intestinal flora in chickens by rRNA fluorescence in situ hybridization (FISH). Seven weeks old conventionally reared Lohmann hens were used to set up the method. To sample ileal intestinal content......, the distal part from Meckels diverticulum to the ileo-caecal junction was removed. Fixation was performed in ethanol and phosphate buffered saline. After washing by centrifugation, the sample was resuspended in pre-heated hybridization buffer with oligonucleotide probe labelled with Cy3 (10ng/µl). The cells...... were hybridized for 24-72h, centrifuged, washed with pre-heated hybridization buffer, centrifuged and resuspended in Millipore quality water before filtration onto a 0.22 µm black polycarbonate filter. The probes used in this study were, LGC354A, LGC354B, LGC354C, Strc493, Bacto1080, Sal3, Chis150, EUB...

  18. Black Hole Blows Big Bubble

    Science.gov (United States)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  19. Scrambling with matrix black holes

    Science.gov (United States)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  20. Life under a black sun

    CERN Document Server

    Opatrný, Tomáš; Bakala, Pavel

    2016-01-01

    Life is dependent on the income of energy with low entropy and the disposal of energy with high entropy. On Earth, the low-entropy energy is provided by solar radiation and the high-entropy energy is disposed as infrared radiation emitted into the cold space. Here we turn the situation around and assume cosmic background radiation as the low-entropy source of energy for a planet orbiting a black hole into which the high-entropy energy is disposed. We estimate the power that can be produced by thermodynamic processes on such a planet, with a particular interest in planets orbiting a fast rotating Kerr black hole as in the science fiction movie {\\em Interstellar}. We also briefly discuss a reverse Dyson sphere absorbing cosmic background radiation from the outside and dumping waste energy to a black hole inside.

  1. Edge phonons in black phosphorus

    Science.gov (United States)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  2. Lee-Wick Black Holes

    CERN Document Server

    Bambi, Cosimo; Wang, Yixu

    2016-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source $M$ exceeds a critical value $M_{\\rm crit}$. For $M > M_{\\rm crit}$ the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for $M = M_{\\rm crit}$ we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  3. Life under a black sun

    Science.gov (United States)

    Opatrný, Tomáš; Richterek, Lukáš; Bakala, Pavel

    2017-01-01

    Life is dependent on the income of energy with low entropy and the disposal of energy with high entropy. On Earth, the low-entropy energy is provided by solar radiation and the high-entropy energy is disposed of as infrared radiation emitted into cold space. Here, we turn the situation around and imagine the cosmic background radiation as the low-entropy source of energy for a planet orbiting a black hole into which the high-entropy energy is expelled. We estimate the power that can be produced by thermodynamic processes on such a planet, with a particular interest in planets orbiting a fast rotating Kerr black hole as in the science fiction movie Interstellar. We also briefly discuss a reverse Dyson sphere absorbing cosmic background radiation from the outside and dumping waste energy to a black hole inside.

  4. Black holes and galaxy formation

    CERN Document Server

    Propst, Raphael J

    2010-01-01

    Galaxies are the basic unit of cosmology. The study of galaxy formation is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning. The physics of galaxy formation is complicated because it deals with the dynamics of stars, thermodynamics of gas and energy production of stars. A black hole is a massive object whose gravitational field is so intense that it prevents any form of matter or radiation to escape. It is hypothesized that the most massive galaxies in the universe- "elliptical galaxies"- grow simultaneously with the supermassive black holes at their centers, giving us much stronger evidence that black holes control galaxy formation. This book reviews new evidence in the field.

  5. Volume inside old black holes

    Science.gov (United States)

    Christodoulou, Marios; De Lorenzo, Tommaso

    2016-11-01

    Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.

  6. Lee-Wick black holes

    Science.gov (United States)

    Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

    2017-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  7. Massive Black Holes and Galaxies

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

  8. Nonextremal black holes are BPS

    CERN Document Server

    Miller, C M; Weinberg, E J; Miller, Christopher M.; Schalm, Koenraad; Weinberg, Erick J.

    2006-01-01

    Extremal charged black holes are BPS solutions. It is commonly thought that their nonextremal counterparts are not. Further, experience with BPS solutions in flat spacetime suggests that all BPS solutions are supersymmetric; i.e. that they are invariant under some supersymmetry charges of either the original field theory or an appropriately extended version thereof. Using nonextremal Reissner-Nordstrom black holes as counterexamples, we show that neither of these expectations is universally valid. These black holes correspond to a one-parameter family of BPS solutions. By showing that no generalized Killing spinor can be constructed for these, we show that there is no supergravity theory for which these BPS solutions preserve a fraction of the supersymmetry, nor is there an associated Witten-Nester positive energy bound.

  9. Disrupting Entanglement of Black Holes

    CERN Document Server

    Leichenauer, Stefan

    2014-01-01

    We study entanglement in thermofield double states of strongly coupled CFTs by analyzing two-sided Reissner-Nordstrom solutions in AdS. The central object of study is the mutual information between a pair of regions, one on each asymptotic boundary of the black hole. For large regions the mutual information is positive and for small ones it vanishes; we compute the critical length scale, which goes to infinity for extremal black holes, of the transition. We also generalize the butterfly effect of Shenker and Stanford to a wide class of charged black holes, showing that mutual information is disrupted upon perturbing the system and waiting for a time of order $\\log E/\\delta E$ in units of the temperature. We conjecture that the parametric form of this timescale is universal.

  10. Black lenses in string theory

    CERN Document Server

    Kunduri, Hari K

    2016-01-01

    We present a new supersymmetric, asymptotically flat, black hole solution to five-dimensional U(1)^3-supergravity which is regular on and outside an event horizon of lens space topology L(2,1). The solution has seven independent parameters and uplifts to a new family of 1/8-supersymmetric D1-D5-P black brane solutions to Type IIB supergravity. The decoupling limit is asymptotically AdS(3) x S^3 x T^4, with a near-horizon geometry that is a twisted product of the near-horizon geometry of the extremal BTZ black hole and L(2,1) x T^4, although it is not (locally) a product space in the bulk. Nevertheless, we find that the Bekenstein-Hawking entropy agrees exactly with the Cardy formula for the degeneracy of CFT states dual to the near-horizon geometry.

  11. Calabi-Yau black holes

    Science.gov (United States)

    Shmakova, Marina

    1997-07-01

    We find the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space and the prepotential F=dABC(XAXBXC/X0). We show that for arbitrary dABC and black hole charges p and q the entropy-area formula depends on combinations of these charges and parameters dABC. These combinations are the solutions of a simple system of algebraic equations. We give a few examples of particular Calabi-Yau moduli spaces for which this system has an explicit solution. For the special case when one of the black hole charges is equal to zero (p0=0) the solution always exists.

  12. Black holes with vector hair

    Science.gov (United States)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  13. Reproductive barriers and hybridity in two spruces, Picea rubens and Picea mariana, sympatric in eastern North America

    Science.gov (United States)

    John E. Major; Alex Mosseler; Kurt H. Johnsen; Om P. Rajora; Debby C. Barsi; K.-H. Kim; J.-M. Park; Moira Campbell

    2005-01-01

    Hybridization between red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) BSP), lateand early-successional species, respectively, has resulted in identification and management problems. We investigated the nature and magnitude of reproductive and life-cycle success barriers in controlled intra- and inter-...

  14. Novel lanthanide hybrid functional materials for high performance luminescence application: The relationship between structures and photophysical behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jun [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Jia, Lei [Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Ma, Yufei; Liu, Xiao; Tian, Hao; Liu, Weisheng [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang, Yu, E-mail: tangyu@lzu.edu.cn [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2012-09-14

    Functional luminescent hybrid materials have emerged as fascinating and promising materials for their versatile applications. In this report, novel efficient luminescent lanthanide (Tb{sup 3+}, Eu{sup 3+}) hybrid materials with a new kind of amide-type {beta}-diketone ligands covalently bonded to the silica gels have been assembled through the sol-gel progresses. The hybrid materials have been characterized by the Fourier transform infrared (FTIR) spectra, UV-vis absorption spectra, powder X-ray diffraction (PXRD), scanning electron microscope (SEM), and thermal analyses. The relationship between structures and photophysical behaviors of these materials was discussed in detail. The materials assembled by the precursors containing aromatic end group (Si-L{sup 1}-Ln) exhibited longer luminescence lifetimes and higher quantum efficiencies, suggesting that the existence of a suitable conjugated system should allow a more efficient energy transfer. Under UV irradiation, the materials emitted either bright green light or red light with different intensity which may lead to potential functional applications in optical devices and electronic devices. Highlights: Black-Right-Pointing-Pointer A new kind of efficient luminescent lanthanide hybrid materials has been assembled. Black-Right-Pointing-Pointer The materials can efficiently emit green or red light under UVA irradiation. Black-Right-Pointing-Pointer The relationship between photophysical behaviors and structures was discussed. Black-Right-Pointing-Pointer A suitable conjugated system should allow a more efficient energy transfer.

  15. Geometric inequalities for black holes

    Energy Technology Data Exchange (ETDEWEB)

    Dain, Sergio [Universidad Nacional de Cordoba (Argentina)

    2013-07-01

    Full text: A geometric inequality in General Relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities, which are valid in the dynamical and strong field regime, play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this talk I will review recent results in this subject. (author)

  16. Black Holes with Zero Mass

    CERN Document Server

    Nucamendi, U; Nucamendi, Ulises; Sudarsky, Daniel

    2000-01-01

    We consider the spacetimes corresponding to static Global Monopoles with interior boundaries corresponding to a Black Hole Horizon and analyze the behavior of the appropriate ADM mass as a function of the horizon radius r_H. We find that for small enough r_H, this mass is negative as in the case of the regular global monopoles, but that for large enough r_H the mass becomes positive encountering an intermediate value for which we have a Black Hole with zero ADM mass.

  17. Black holes and warped spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, W.J. III

    1979-01-01

    Black holes (BHs) and their warping effect on spacetime are described, beginning with a discussion on stellar evolution that includes white dwarfs, supernovas and neutron stars. The structure of static, rotating, and electrically charged BHs are considered, as well as the general theory of relativity, quantum mechanics, the Einstein-Rosen bridge, and wormholes in spacetime. Attention is also given to gravitational lenses, various space geometries, quasars, Seyfert galaxies, supermassive black holes, the evaporation and particle emission of BHs, and primordial BHs, including their temperature and lifetime.

  18. Chaotization inside Quantum Black Holes

    CERN Document Server

    Addazi, Andrea

    2015-01-01

    We show how the horizon geometry and entropy of a Semiclassical Black Hole can be reconstructed from a system of $N>>1$ horizonless conic singularities with average opening angle at the horizon $\\langle \\Theta \\rangle=2\\pi$. This conclusion is strongly motivated by a generalized Wheeler-De Witt equation for quantum black holes. We will argument how infalling information will be inevitably chaotized in these systems. A part of the initial probability density will be trapped inside the system, in back and forth scatterings among conic singularities, for a characteristic time close to the Semiclassical BH life-time. Further implications on information paradoxes are discussed.

  19. Energy Efficiency Comparison between Hydraulic Hybrid and Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Jia-Shiun Chen

    2015-05-01

    Full Text Available Conventional vehicles tend to consume considerable amounts of fuel, which generates exhaust gases and environmental pollution during intermittent driving cycles. Therefore, prospective vehicle designs favor improved exhaust emissions and energy consumption without compromising vehicle performance. Although pure electric vehicles feature high performance and low pollution characteristics, their limitations are their short driving range and high battery costs. Hybrid electric vehicles (HEVs are comparatively environmentally friendly and energy efficient, but cost substantially more compared with conventional vehicles. Hydraulic hybrid vehicles (HHVs are mainly operated using engines, or using alternate combinations of engine and hydraulic power sources while vehicles accelerate. When the hydraulic system accumulator is depleted, the conventional engine reengages; concurrently, brake-regenerated power is recycled and reused by employing hydraulic motor–pump modules in circulation patterns to conserve fuel and recycle brake energy. This study adopted MATLAB Simulink to construct complete HHV and HEV models for backward simulations. New European Driving Cycles were used to determine the changes in fuel economy. The output of power components and the state-of-charge of energy could be retrieved. Varying power component models, energy storage component models, and series or parallel configurations were combined into seven different vehicle configurations: the conventional manual transmission vehicle, series hybrid electric vehicle, series hydraulic hybrid vehicle, parallel hybrid electric vehicle, parallel hydraulic hybrid vehicle, purely electric vehicle, and hydraulic-electric hybrid vehicle. The simulation results show that fuel consumption was 21.80% lower in the series hydraulic hybrid vehicle compared to the series hybrid electric vehicle; additionally, fuel consumption was 3.80% lower in the parallel hybrid electric vehicle compared to the

  20. Irreversible gravitational collapse: black stars or black holes?

    CERN Document Server

    Corda, Christian

    2011-01-01

    It is well known that the concept of black hole has been considered very fascinating by scientists even before the introduction of Einstein's general relativity. They should be the final result of an irreversible gravitational collapse of very massive bodies. However, an unsolved problem concerning such objects is the presence of a space-time singularity in their core. Such a problem was present starting by the first historical papers concerning black holes. It is a common opinion that this problem could be solved when a correct quantum gravity theory will be, finally, constructed. In this work we review a way to remove black hole singularities at a classical level i.e. without arguments of quantum gravity. By using a particular non-linear electrodynamics Lagrangian, an exact solution of Einstein field equations is shown. The solution prevents the collapsing object to reach the gravitational radius, thus the final result becomes a black star, i.e. an astrophysical object where both of singularities and event ...