The nucleus: a black box being opened.
van Driel, R; Humbel, B; de Jong, L
1991-12-01
Until recently our knowledge about the structural and functional organization of the cell nucleus was very limited. Recent technical developments in the field of ultrastructural analysis, combined with ongoing research on the properties of the nuclear matrix, give new insight into how the nucleus is structured. Two types of observations shape our ideas about nuclear organization. First, most nuclear functions (replication, transcription, RNA processing, and RNA transport) are highly localized within the nucleus, rather than diffusely distributed. Moreover, they are associated with the nuclear matrix. Second, chromatin is organized in discrete loops, bordered by nuclear matrix attachment sequences (MARs). Each loop may contain one or several genes. The arrangement of chromatin in loops has profound consequences for the regulation of gene expression.
Applying the elastic model for various nucleus-nucleus fusion
International Nuclear Information System (INIS)
The Elastic Model of two free parameters m,d given by Scalia has been used for wider energy regions to fit the available experimental data for potential barriers and cross sections. In order to generalize Scalia's formula in both sub- and above-barrier regions, we calculated m, d for pairs rather than those given by Scalia and compared the calculated cross sections with the experimental data. This makes a generalization of the Elastic Model in describing fusion process. On the other hand, Scalia's range of interacting systems was 24 ≤ A ≤194 where A is the compound nucleus mass number. Our extension of that model includes an example of the pairs of A larger than his final limit aiming to make it as a general formula for any type of reactants: light, intermediate or heavy systems. A significant point is the comparison of Elastic Model calculations with the well known methods studying complete fusion and compound nucleus formation, namely with the resultants of using Proximity potential with either Sharp or Smooth cut-off approximations
Contemporary models of the atomic nucleus
Nemirovskii, P E
2013-01-01
Contemporary Models of the Atomic Nucleus discusses nuclear structure and properties, expounding contemporary theoretical concepts of the low-energy nuclear processes underlying in nuclear models. This book focuses on subjects such as the optical nuclear model, unified or collective model, and deuteron stripping reaction. Other topics discussed include the basic nuclear properties; shell model; theoretical analysis of the shell model; and radiative transitions and alpha-decay. The deuteron theory and the liquid drop nuclear model with its application to fission theory are also mentioned, but o
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.
Black hole in the West Nucleus of Arp 220
Downes, D
2007-01-01
We present new observations with the IRAM Interferometer, in its longest-baseline configuration, of the CO(2-1) line and the 1.3mm dust radiation from the Arp 220 nuclear region. The dust source in the West nucleus has a size of 0.19 x 0.13 arcsec and a 1.3mm brightness temperature of 90K. This implies that the dust ring in the West nucleus has a high opacity, with tau = 1 at 1.1mm. Not only is the dust ring itself optically thick in the submm and far-IR, but it is surrounded by the previously-known, rapidly rotating molecular disk of size 0.5 arcsec that is also optically thick in the mid-IR. The molecular ring is cooler than the hot dust disk because the CO(2-1) line is seen in absorption against the dust disk. The dust ring is massive (1E9 solar masses), compact (radius 35pc), and hot (true dust temperature 170K). It resembles rather strikingly the dust ring detected around the quasar APM 08279+52, and is most unlike the warm, extended dust sources in starburst galaxies. Because there is a strong temperatu...
Modeling black hole evaporation
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.
Bender, R; Bower, G; Green, R; Thomas, J; Danks, A C; Gull, T R; Hutchings, J B; Joseph, C L; Kaiser, M E; Lauer, T R; Nelson, C H; Richstone, D O; Weistrop, D; Woodgate, B; Bender, Ralf; Kormendy, John; Bower, Gary; Green, Richard; Thomas, Jens; Danks, Anthony C.; Gull, Theodore; Lauer, Tod R.; Nelson, Charles H.; Richstone, Douglas; Weistrop, Donna; Woodgate, Bruce
2005-01-01
We present HST spectroscopy of the nucleus of M31 obtained with STIS. Spectra taken around the CaT lines at 8500 see only the red giants in the double bright- ness peaks P1 and P2. In contrast, spectra taken at 3600-5100 A are sensitive to the tiny blue nucleus embedded in P2, the lower surface brightness red nucleus. P2 has a K-type spectrum, but the embedded blue nucleus has an A-type spectrum with strong Balmer absorption lines. Given the small likelihood for stellar collisions, a 200 Myr old starburst appears to be the most plausible origin of the blue nucleus. In stellar population, size, and velocity dispersion, the blue nucleus is so different from P1 and P2 that we call it P3. The line-of-sight velocity distributions of the red stars in P1+P2 strengthen the support for Tremaine s eccentric disk model. The kinematics of P3 is consistent with a circular stellar disk in Keplerian rotation around a super-massive black hole with M_bh = 1.4 x 10^8 M_sun. The P3 and the P1+P2 disks rotate in the same sense a...
Active galactic nucleus black hole mass estimates in the era of time domain astronomy
International Nuclear Information System (INIS)
We investigate the dependence of the normalization of the high-frequency part of the X-ray and optical power spectral densities (PSDs) on black hole mass for a sample of 39 active galactic nuclei (AGNs) with black hole masses estimated from reverberation mapping or dynamical modeling. We obtained new Swift observations of PG 1426+015, which has the largest estimated black hole mass of the AGNs in our sample. We develop a novel statistical method to estimate the PSD from a light curve of photon counts with arbitrary sampling, eliminating the need to bin a light curve to achieve Gaussian statistics, and we use this technique to estimate the X-ray variability parameters for the faint AGNs in our sample. We find that the normalization of the high-frequency X-ray PSD is inversely proportional to black hole mass. We discuss how to use this scaling relationship to obtain black hole mass estimates from the short timescale X-ray variability amplitude with precision ∼0.38 dex. The amplitude of optical variability on timescales of days is also anticorrelated with black hole mass, but with larger scatter. Instead, the optical variability amplitude exhibits the strongest anticorrelation with luminosity. We conclude with a discussion of the implications of our results for estimating black hole mass from the amplitude of AGN variability.
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
International Nuclear Information System (INIS)
We investigate the effect of active galactic nucleus (AGN) variability on the observed connection between star formation and black hole accretion in extragalactic surveys. Recent studies have reported relatively weak correlations between observed AGN luminosities and the properties of AGN hosts, which has been interpreted to imply that there is no direct connection between AGN activity and star formation. However, AGNs may be expected to vary significantly on a wide range of timescales (from hours to Myr) that are far shorter than the typical timescale for star formation (≳100 Myr). This variability can have important consequences for observed correlations. We present a simple model in which all star-forming galaxies host an AGN when averaged over ∼100 Myr timescales, with long-term average AGN accretion rates that are perfectly correlated with the star formation rate (SFR). We show that reasonable prescriptions for AGN variability reproduce the observed weak correlations between SFR and L AGN in typical AGN host galaxies, as well as the general trends in the observed AGN luminosity functions, merger fractions, and measurements of the average AGN luminosity as a function of SFR. These results imply that there may be a tight connection between AGN activity and SFR over galaxy evolution timescales, and that the apparent similarities in rest-frame colors, merger rates, and clustering of AGNs compared to 'inactive' galaxies may be due primarily to AGN variability. The results provide motivation for future deep, wide extragalactic surveys that can measure the distribution of AGN accretion rates as a function of SFR.
Poberezhnyuk, R V; Gorenstein, M I
2015-01-01
The Statistical Model of the Early Stage, SMES, describes a transition between confined and deconfined phases of strongly interacting matter created in nucleus-nucleus collisions. The model was formulated in the late 1990s for central Pb+Pb collisions at the CERN SPS energies. It predicted several signals of the transition (onset of deconfinement) which were later observed by the NA49 experiment. The grand canonical ensemble was used to calculate entropy and strangeness production. This approximation is valid for reactions with mean multiplicities of particles carrying conserved charges being significantly larger than one. Recent results of NA61/SHINE on hadron production in inelastic p+p interactions suggest that the deconfinement may also take place in these reactions. However, in this case mean multiplicity of particles with non-zero strange charge is smaller than one. Thus for the modeling of p+p interactions the exact strangeness conservation has to be implemented in the SMES. This extension of the SMES ...
Semiclassical model for single-particle transitions in nucleus-nucleus interactions
International Nuclear Information System (INIS)
A previously elaborated semiclassical one-body model for the dynamics of a single particle, moving in two potentials, in heavy-ion reactions or in fissioning systems has been extended with respect to the inclusion of angular momenta and more realistic separable potentials. The collective relative motion is assumed to proceed along a trajectory which is calculated from classical equations of motion including conservative and phenomenological friction forces. The formalism has been derived involving three-dimensional trajectories for symmetric as well as for asymmetric nucleus-nucleus systems. The model allows for the calculation of correct quantum mechanical transition amplitudes to final bound and continuum states. It has been applied for the investigation of the excitation of a neutron during a fission process, covering also non-statistical differential emission probabilities. From the numerical calculations, using parameters adapted to 252Cf(sf), one can conclude that in the underlying model without 'sudden' processes the energy spectrum consists of two parts. The low lying component is created in the neck region while a high lying part seems to be governed mainly by the dynamics of the underlying collective motion rather than by the specific initial conditions. (orig.)
A Heuristic Model for the Active Galactic Nucleus Based on the Planck Vacuum Theory
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2009-07-01
Full Text Available The standard explanation for an active galactic nucleus (AGN is a “central engine” consisting of a hot accretion disk surrounding a supermassive black hole [1, p. 32]. Energy is generated by the gravitational infall of material which is heated to high tem- peratures in this dissipative accretion disk. What follows is an alternative model for the AGN based on the Planck vacuum (PV theory [2, Appendix], where both the energy of the AGN and its variable luminosity are explained in terms of a variable photon flux emanating from the PV.
A Heuristic Model for the Active Galactic Nucleus Based on the Planck Vacuum Theory
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2009-07-01
Full Text Available The standard explanation for an active galactic nucleus (AGN is a "central engine" consisting of a hot accretion disk surrounding a supermassive black hole. Energy is generated by the gravitational infall of material which is heated to high temperatures in this dissipative accretion disk. What follows is an alternative model for the AGN based on the Planck vacuum (PV theory, where both the energy of the AGN and its variable luminosity are explained in terms of a variable photon flux emanating from the PV.
Nuclear mean field and double-folding model of the nucleus-nucleus optical potential
Khoa, Dao T; Loan, Doan Thi; Loc, Bui Minh
2016-01-01
Realistic density dependent CDM3Yn versions of the M3Y interaction have been used in an extended Hartree-Fock (HF) calculation of nuclear matter (NM), with the nucleon single-particle potential determined from the total NM energy based on the Hugenholtz-van Hove theorem that gives rise naturally to a rearrangement term (RT). Using the RT of the single-nucleon potential obtained exactly at different NM densities, the density- and energy dependence of the CDM3Yn interactions was modified to account properly for both the RT and observed energy dependence of the nucleon optical potential. Based on a local density approximation, the double-folding model of the nucleus-nucleus optical potential has been extended to take into account consistently the rearrangement effect and energy dependence of the nuclear mean-field potential, using the modified CDM3Yn interactions. The extended double-folding model was applied to study the elastic $^{12}$C+$^{12}$C and $^{16}$O+$^{12}$C scattering at the refractive energies, wher...
An eccentric disk model for the nucleus of M31
Tremaine, S
1995-01-01
The nucleus of M31 may be a thick eccentric disk, composed of stars traveling on nearly Keplerian orbits around a black hole or other dark compact object. This hypothesis reproduces most of the features seen in HST photometry of the center of M31; in particular the bright off-center source P1 is the apoapsis of the disk. An eccentric disk can also explain the rotation curve and asymmetric dispersion profile revealed by ground-based observations. The central object must be smaller than 1 pc so that the potential felt by the disk is nearly Keplerian. The disk eccentricity may be excited by a secular instability driven by dynamical friction from the bulge.
Model Equations: "Black Box" Reconstruction
Bezruchko, Boris P.; Smirnov, Dmitry A.
Black box reconstruction is both the most difficult and the most tempting modelling problem when any prior information about an appropriate model structure is lacking. An intriguing thing is that a model capable of reproducing an observed behaviour or predicting further evolution should be obtained only from an observed time series, i.e. "from nothing" at first sight. Chances for a success are not large. Even more so, a "good" model would become a valuable tool to characterise an object and understand its dynamics. Lack of prior information causes one to utilise universal model structures, e.g. artificial neural networks, radial basis functions and algebraic polynomials are included in the right-hand sides of dynamical model equations. Such models are often multi-dimensional and involve quite many free parameters.
Bacon, R.; Emsellem, E.; Monnet, G.; Nieto, J. L.
1993-01-01
Sub-arcsecond imagery (HRCAM, 0".35 - 0".57 FWHM) and two-dimensional spectrography (TIGER, 0".9 FWHM) of the central nucleus of M31 have been obtained at CFHT. The photometric data clearly show the double-peaked nucleus, in excellent agreement with a recent HST image by Lauer et al. 1993. We built deconvolved surface brightness models, using the multi-Gaussian expansion method. We then perform a detailed morphological analysis of the three central photometric components (bulge, nucleus and b...
BLACK-SCHOLESOV MODEL VREDNOTENJA OPCIJ
Najvirt, Damir
2010-01-01
V diplomski nalogi obravnavam Black-Scholesov model vrednotenja opcij, ki sta ga leta 1973 razvila Fisher Black in Myron Scholes. Black-Scholesov model je primeren za vrednotenje več vrst opcij, vendar pa v praksi prihaja do velikih razhajanj med vrednostjo opcije izračunano po Black-Scholesovem modelu in tržno ceno opcije. To razhajanje je že vrsto let podlaga raziskav, v katere se vključujejo tudi matematiki in fiziki. S stališča popularizacije fizike je predvsem zanimiva predpostavka model...
Qubit Models of Black Hole Evaporation
Avery, Steven G.
2011-01-01
Recently, several simple quantum mechanical toy models of black hole evaporation have appeared in the literature attempting to illuminate the black hole information paradox. We present a general class of models that is large enough to describe both unitary and nonunitary evaporation, and study a few specific examples to clarify some potential confusions regarding recent results. We also generalize Mathur's bound on small corrections to black hole dynamics. Conclusions are then drawn about the...
Bacon, R; Monnet, G; Nieto, J L
1993-01-01
Sub-arcsecond imagery (HRCAM, 0".35 - 0".57 FWHM) and two-dimensional spectrography (TIGER, 0".9 FWHM) of the central nucleus of M31 have been obtained at CFHT. The photometric data clearly show the double-peaked nucleus, in excellent agreement with a recent HST image by Lauer et al. 1993. We built deconvolved surface brightness models, using the multi-Gaussian expansion method. We then perform a detailed morphological analysis of the three central photometric components (bulge, nucleus and bright secondary peak) and derive various spatial luminosity models (oblate and triaxial). Stellar velocity and velocity dispersion fields were derived from the TIGER data: the former displays an extremely rapid rotation around the true center of the galaxy, while the latter exhibits a peaked structure offset in the opposite direction of the brightest light peak. Neglecting these offsets,both extended versions of the virial theorem and detailed hydrodynamical models confirm the classical strong central mass concentration, ...
Relativistic models for quasielastic electron and neutrino-nucleus scattering
Giusti, Carlotta; 10.1051/epjconf/20123814004
2012-01-01
Relativistic models developed within the framework of the impulse approximation for quasielastic (QE) electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI) in the inclusive scattering are compared. In the relativistic Green's function (RGF) model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF) model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE) MiniBooNE cross sections.
Black Hole Universe Model and Dark Energy
Zhang, Tianxi
2011-01-01
Considering black hole as spacetime and slightly modifying the big bang theory, the author has recently developed a new cosmological model called black hole universe, which is consistent with Mach principle and Einsteinian general relativity and self consistently explains various observations of the universe without difficulties. According to this model, the universe originated from a hot star-like black hole and gradually grew through a supermassive black hole to the present universe by accreting ambient material and merging with other black holes. The entire space is infinitely and hierarchically layered and evolves iteratively. The innermost three layers are the universe that we lives, the outside space called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer has an infinite radius and zero limits for both the mass density and absolute temperature. All layers or universes are governed by the same physics, the Einstein general relativity with the Robertson-Walker metric of spacetime, and tend to expand outward physically. When one universe expands out, a new similar universe grows up from its inside black holes. The origin, structure, evolution, expansion, and cosmic microwave background radiation of black hole universe have been presented in the recent sequence of American Astronomical Society (AAS) meetings and published in peer-review journals. This study will show how this new model explains the acceleration of the universe and why dark energy is not required. We will also compare the black hole universe model with the big bang cosmology.
Modeling Flows Around Merging Black Hole Binaries
van Meter, James R.; Wise, John H.; Miller, M. Coleman; Reynolds, Christopher S.; Centrella, Joan M.; Baker, John G.; Boggs, William D.; Kelly, Bernard J.; McWilliams, Sean T.
2009-01-01
Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the stron...
Modeling Flows Around Merging Black Hole Binaries
van Meter, James R; Miller, M Coleman; Reynolds, Christopher S; Centrella, Joan M; Baker, John G; Boggs, William D; Kelly, Bernard J; McWilliams, Sean T
2009-01-01
Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm ...
The supermassive black hole and double nucleus of the core elliptical NGC5419
Mazzalay, X; Saglia, R P; Wegner, G A; Bender, R; Erwin, P; Fabricius, M H; Rusli, S
2016-01-01
We obtained adaptive-optics assisted SINFONI observations of the central regions of the giant elliptical galaxy NGC5419 with a spatial resolution of 0.2 arcsec ($\\approx 55$ pc). NGC5419 has a large depleted stellar core with a radius of 1.58 arcsec (430 pc). HST and SINFONI images show a point source located at the galaxy's photocentre, which is likely associated with the low-luminosity AGN previously detected in NGC5419. Both the HST and SINFONI images also show a second nucleus, off-centred by 0.25 arcsec ($\\approx 70$ pc). Outside of the central double nucleus, we measure an almost constant velocity dispersion of $\\sigma \\sim 350$ km/s. In the region where the double nucleus is located, the dispersion rises steeply to a peak value of $\\sim 420$ km/s. In addition to the SINFONI data, we also obtained stellar kinematics at larger radii from the South African Large Telescope. While NGC5419 shows low rotation ($v < 50$ km/s), the central regions (inside $\\sim 4 \\, r_b$) clearly rotate in the opposite direc...
Computational modeling of pedunculopontine nucleus deep brain stimulation
Zitella, Laura M.; Mohsenian, Kevin; Pahwa, Mrinal; Gloeckner, Cory; Johnson, Matthew D.
2013-08-01
Objective. Deep brain stimulation (DBS) near the pedunculopontine nucleus (PPN) has been posited to improve medication-intractable gait and balance problems in patients with Parkinson's disease. However, clinical studies evaluating this DBS target have not demonstrated consistent therapeutic effects, with several studies reporting the emergence of paresthesia and oculomotor side effects. The spatial and pathway-specific extent to which brainstem regions are modulated during PPN-DBS is not well understood. Approach. Here, we describe two computational models that estimate the direct effects of DBS in the PPN region for human and translational non-human primate (NHP) studies. The three-dimensional models were constructed from segmented histological images from each species, multi-compartment neuron models and inhomogeneous finite element models of the voltage distribution in the brainstem during DBS. Main Results. The computational models predicted that: (1) the majority of PPN neurons are activated with -3 V monopolar cathodic stimulation; (2) surgical targeting errors of as little as 1 mm in both species decrement activation selectivity; (3) specifically, monopolar stimulation in caudal, medial, or anterior PPN activates a significant proportion of the superior cerebellar peduncle (up to 60% in the human model and 90% in the NHP model at -3 V) (4) monopolar stimulation in rostral, lateral or anterior PPN activates a large percentage of medial lemniscus fibers (up to 33% in the human model and 40% in the NHP model at -3 V) and (5) the current clinical cylindrical electrode design is suboptimal for isolating the modulatory effects to PPN neurons. Significance. We show that a DBS lead design with radially-segmented electrodes may yield improved functional outcome for PPN-DBS.
Zhang, Song; Chen, Jin-Hui; Zhong, Chen
2014-01-01
The particle production of Kaon and $\\Lambda$ are studied in nucleus-nucleus collisions at relativistic energy based on a chemical equilibrium blast-wave model. The transverse momentum spectra of Kaon and $\\Lambda$ at the kinetic freeze-out stage from our model are in good agreement with the experimental results. The kinetic freeze-out parameters of temperature ($T_{kin}$) and radial flow parameter $\\rho_{0}$ are presented for the FOPI, RHIC and LHC energies. And the resonance decay effect is also discussed. The systematic study for beam energy dependence of the strangeness particle production will help us to better understand the properties of the matter created in heavy-ion collisions at the kinetic freeze-out stage.
Institute of Scientific and Technical Information of China (English)
Qijin Huang; Guoquan Liu; Yong Li; Jin Gao; Zhengqiu Gu; Yuanzheng Ma; Haibin Xue
2004-01-01
Pilot biomechanical design of biomaterials for artificial nucleus prosthesis was carried out based on the 3D finite-element method. Two 3D models of lumbar intervertebral disc respectively with a real human nucleus and with the nucleus removed were developed and validated using published experimental and clinical data. Then the models with a stainless steel nucleus prosthesis implanted and with polymer nucleus prostheses of various properties implanted were used for the 3D finite-element biomechanical analysis. All the above simulation and analysis were carried out for the L4/L5 disc under a human worst-daily compression load of 2000 N. The results show that the polymer materials with Young's modulus of elasticity E = 0.1-100 MPa and Poisson's ratio v=0.35-0.5 are suitable to produce artificial nucleus prosthesis in view of biomechanical consideration.
Black Hole Lightning from the Peculiar Gamma-Ray Loud Active Galactic Nucleus IC 310
Glawion, Dorit Eisenacher; Mannheim, Karl; Colin, Pierre; Kadler, Matthias; Schulz, Robert; Ros, Eduardo; Bach, Uwe; Krauß, Felicia; Wilms, Jörn
2015-01-01
The nearby active galaxy IC 310, located in the outskirts of the Perseus cluster of galaxies is a bright and variable multi-wavelength emitter from the radio regime up to very high gamma-ray energies above 100 GeV. Originally, the nucleus of IC 310 has been classified as a radio galaxy. However, studies of the multi-wavelength emission showed several properties similarly to those found from blazars as well as radio galaxies. In late 2012, we have organized the first contemporaneous multi-wavelength campaign including radio, optical, X-ray and gamma-ray instruments. During this campaign an exceptionally bright flare of IC 310 was detected with the MAGIC telescopes in November 2012 reaching an averaged flux level in the night of up to one Crab above 1 TeV with a hard spectrum over two decades in energy. The intra-night light curve showed a series of strong outbursts with flux-doubling time scales as fast as a few minutes. The fast variability constrains the size of the gamma-ray emission regime to be smaller th...
Canonical Ensemble Model for Black Hole Radiation
Indian Academy of Sciences (India)
Jingyi Zhang
2014-09-01
In this paper, a canonical ensemble model for the black hole quantum tunnelling radiation is introduced. In this model the probability distribution function corresponding to the emission shell is calculated to second order. The formula of pressure and internal energy of the thermal system is modified, and the fundamental equation of thermodynamics is also discussed.
Chapter 8. Black Holes in Braneworld Models
Tanahashi, N.; Tanaka, T.
In this review, we summarize current understandings of blackhole solutions in various braneworld models, including the Arkani-Hamed-Dimopoulos-Dvali model, the Randall-Sundrum (RS) models, Karch-Randall (KR) model and the Dvali-Gabadadze-Porrati model. After illustrating basic properties of each braneworld model, we introduce the bulk/brane correspondence in the RS and KR braneworld models, adding supporting evidence for it. We then summarize the studies on braneworld black hole solutions, which consist of constructing exact or approximate solutions and investigating the phase diagram of solutions. In the study of phase diagram, we will also expound the implications of the bulk/brane correspondence to the braneworld black holes.
A New Cosmological Model: Black Hole Universe
Directory of Open Access Journals (Sweden)
Zhang T. X.
2009-07-01
Full Text Available A new cosmological model called black hole universe is proposed. According to this model, the universe originated from a hot star-like black hole with several solar masses, and gradually grew up through a supermassive black hole with billion solar masses to the present state with hundred billion-trillion solar masses by accreting ambient mate- rials and merging with other black holes. The entire space is structured with infinite layers hierarchically. The innermost three layers are the universe that we are living, the outside called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer is infinite in radius and limits to zero for both the mass density and absolute temperature. The relationships among all layers or universes can be connected by the universe family tree. Mathematically, the entire space can be represented as a set of all universes. A black hole universe is a subset of the en- tire space or a subspace. The child universes are null sets or empty spaces. All layers or universes are governed by the same physics - the Einstein general theory of relativity with the Robertson-walker metric of spacetime - and tend to expand outward physically. The evolution of the space structure is iterative. When one universe expands out, a new similar universe grows up from its inside. The entire life of a universe begins from the birth as a hot star-like or supermassive black hole, passes through the growth and cools down, and expands to the death with infinite large and zero mass density and absolute temperature. The black hole universe model is consistent with the Mach principle, the observations of the universe, and the Einstein general theory of relativity. Its various aspects can be understood with the well-developed physics without any difficulty. The dark energy is not required for the universe to accelerate its expansion. The inflation is not necessary because the black hole universe
Black Scholes’ model and Bollinger bands
Liu, Wei; Huang, Xudong; Zheng, Weian
2006-11-01
Bollinger bands are well-known in stock market as a popular technical analysis tool. We found that Black-Scholes stock price model had this Bollinger bands property also. In this paper, we give the proof of this phenomenon, and give a new distribution of a statistics generated by the Bollinger bands.
Simmons, Donna M.; Larry W Swanson
2008-01-01
As a starting point for constructing a high resolution, resliceable computer graphics model for the extraction, quantitative analysis, display, and modeling of neuroanatomical data the outer border and the boundaries of inner divisions and parts of the paraventricular nucleus have been drawn for all 39 serial histological sections prepared for a published reference atlas of the rat brain. This careful parceling revealed three new features of paraventricular nucleus topography: the full rostra...
Institute of Scientific and Technical Information of China (English)
WEI Liang; LIU Yu-Xin
2005-01-01
@@ By taking the BUU model, we simulate the superheavy element synthesis reaction. With the rotation effect being included in the B UU model, the effect of the non-centrality of the reaction 48 Ca + 238U→ 286112 is studied. It is shown that the promising impact parameter in the synthesis process can be released from zero to a value little smaller than the radius of the smaller nucleus involved in the reaction. Meanwhile, the compound nucleus may involve rich shape phases.
Choi, S Y; Jang, J H; Song, H S; Park, Seong Chan
2001-01-01
We study the elastic scattering of the lightest neutralino with a nucleus in the framework of the minimal supersymmetric standard model (MSSM) with explicit flavor preserving CP violation, including the one-loop CP-violating neutral Higgs-boson mixing effects induced dominantly by the CP phases in the top and bottom (s)quark sectors. We construct the most general form of the effective Lagrangian for the neutralino-nucleus scattering in the limit of vanishing momentum transfers and then we perform a comprehensive analysis of the effects of the complex CP phases on the mass spectra of the lightest neutralino, neutral Higgs bosons and top squarks, and on the the spin-dependent and spin-independent neutralino-nucleus scattering cross section for three neucleus targets F, Si and Ge. The CP phases can reduce or enhance the neutralino-nucleus cross sections significantly, depending on the values of the real parameters in the MSSM.
A holographic model for black hole complementarity
Lowe, David A
2016-01-01
In the version of black hole complementarity advocated by the authors, interior infalling degrees of freedom evolve according to the usual semiclassical effective field theory, generating the black hole interior via propagation along geodesics. Meanwhile the exterior degrees of freedom evolve according to an exact description of holographic origin. The infalling degrees of freedom have a complementary description in terms of outgoing Hawking radiation and must eventually decohere with respect to the exterior Hamiltonian, leading to apparent violations of quantum mechanics for an infaller. Trace distance is used to quantify the difference between these complementary time evolutions, and to define the decoherence time and the scrambling time. In a particular model for the holographic theory which exhibits fast scrambling, we show these timescales coincide. Moreover we propose a dictionary between the holographic theory and the bulk description where mean field evolution corresponds to the evolution with respect...
The lamppost model of accreting black holes
Zdziarski, A.
2016-06-01
Niedzwiecki, Zdziarski & Szanecki (2016, ApJL, submitted) have studied the lamppost model, in which the X-ray source in accreting black-hole systems is located on the rotation axis close to the horizon. We point out a number of inconsistencies in the widely used lamppost model relxilllp. They appear to invalidate those model fitting results for which the source distances from the horizon are within several gravitational radii. Furthermore, we note that if those results were correct, most of the photons produced in the lamppost would be trapped by the black hole, and the source luminosity as measured at infinity would be much larger than that observed. This appears to be in conflict with the observed smooth state transitions between the hard and soft states of X-ray binaries. The required increase of the accretion rate and the associated efficiency reduction present also a problem for AGNs. Then, those models imply the luminosity measured in the local frame much higher than the dissipated power due to time dilation and redshift, and the electron temperature significantly higher than that observed. We show that these conditions imply that the fitted sources would be out of the pair equilibrium.
Implications of the Glauber model for inelastic hadron-nucleus scattering
International Nuclear Information System (INIS)
The Glauber model for elastic hadron-nucleus scattering is extended to inelastic processes by supplementing it with the Abramovski, Gribov, Kancheli cutting rules. Inelastic screening due to low mass states is also included. The results can be interpreted in terms of the probabilistic multiple collision model. The mutual relationship of the two approaches is discussed. (author)
Modeling mesoscale circulation of the Black Sea
Korotenko, K. A.
2015-11-01
An eddy-resolving (1/30)° version of the DieCAST low-dissipative model, adapted to the Black Sea circulation, is presented. Under mean climatological forcing, the model realistically reproduces major dominant large-scale and mesoscale structures of seasonal sea circulation, including the Rim Current, coastal anticyclonic eddies, mushroom currents, etc. Due to its extremely low dissipation and high resolution, the model makes it possible to trace the development of the baroclinic instability along the Turkish and Caucasian coasts, reproduce mesoscale structures generated by this mechanism, and assess the scales of these structures. The model also realistically reproduces short-term effects of bora winds on the evolution of subsurface layer structures.
Modulated Inflation Models and Primordial Black Holes
Erfani, Encieh
2014-01-01
For the first time, the running of the running of the spectral index, $\\beta_s$ has been measured by Planck. This parameter is crucial for dark matter Primordial Black Holes (PBHs) formation. We study the PBHs formation in inflation potentials with superimposed periodic oscillations. We show that the value of $\\beta_s$ suggested by the recent CMB data can be easily explained in these models. As a by-product we also show that the non-production of (long--lived) PBHs puts stronger upper bound on $\\beta_s$.
Modulated inflation models and primordial black holes
Erfani, Encieh
2014-04-01
For the first time, the running of the running of the spectral index βs has been measured by Planck. This parameter is crucial for dark matter primordial black holes (PBHs) formation. We study the PBHs formation in inflation potentials with superimposed periodic oscillations. We show that the value of βs suggested by the recent cosmic microwave background data is easily explained in these models. As a by-product, we also show that the nonproduction of (long-lived) PBHs puts a stronger upper bound on βs.
Different discharge properties of facial nucleus motoneurons following neurotmesis in a rat model.
Shi, Suming; Xu, Lei; Li, Jianfeng; Han, Yuechen; Wang, Haibo
2016-08-26
Facial nucleus motoneurons innervating the facial expressive muscles are involved in a wide range of motor activities, however, the types of movement related neurons and their electrophysiological transformation after peripheral facial nerve injury haven't been revealed. This study was designed to elucidate the types of facial nucleus motoneurons and their alterations of discharge parameters following peripheral facial nerve injury in vivo. Here we set up a rat model by implanting electrode arrays into the brainstem and recorded the electrophysiological signals of facial nucleus neurons in the intact rats for 5 days, then transected the trunk of facial nerve (TF), and continued the record for 4 weeks. At the 4th week post-surgery, the morphological changes of TFs were analyzed. In this paper, we described two types of putative facial nucleus motoneurons based on their electrophysiological properties and their firing frequency adaptation. Type I motoneurons (n=57.6%) were characterized by a sustained spike adaptation, Type II motoneurons (n=26.2%) were identified by a phasic fast spike firing. Facial palsy and synkinesia, caused by neurotmesis of TF, were accompanied by firing rates reduction and firing pattern alteration of motoneurons. Our findings suggest the presence of two types of facial nucleus motorneurons, and their response patterns after neurotmesis support the notion that the discharge pattern of motorneurons may play an important role in the facial nerve function. PMID:27423319
Spin dependence of even-even nucleus shape in the model of Davydov-Chaban
International Nuclear Information System (INIS)
The shape parameters of the even-even nuclei 154Gd, 156,158,160Dy, 164,168Er, 168Yb, 176Hf, 180W are calculated within the phenomenological model of the nonaxial soft by β-oscillation deformed nucleus. The spin dependence of the softness, nonaxiality and energy factor is assumed
Anomalies in option pricing: the Black-Scholes model revisited
Peter Fortune
1996-01-01
In 1973, Myron Scholes and the late Fischer Black published their seminal paper on option pricing. The Black-Scholes model revolutionized financial economics in several ways: It contributed to our understanding of a wide range of contracts with option-like features, and it allowed us to revise our understanding of traditional financial instruments. This article addresses the question of how well the Black-Scholes model of option pricing works. The goal is to acquaint a general audience with t...
Neutrino nucleus reactions within the GiBUU model
Lalakulich, O; Mosel, U
2011-01-01
The GiBUU model, which implements all reaction channels relevant at medium neutrino energy, is used to investigate the neutrino and antineutrino scattering on iron. Results for integrated cross sections are compared with NOMAD and MINOS data. It is shown, that final state interaction can noticeably change the spectra of the outgoing hadrons. Predictions for the Miner$\
MODELING THE MOLECULAR COMPOSITION IN AN ACTIVE GALACTIC NUCLEUS DISK
Energy Technology Data Exchange (ETDEWEB)
Harada, Nanase [Max Planck Institute for Radio Astronomy, D-53121 Bonn (Germany); Thompson, Todd A. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); Herbst, Eric [Departments of Chemistry, Astronomy, and Physics, University of Virginia, Charlottesville, VA 22904 (United States)
2013-03-10
We use a high-temperature chemical network to derive the molecular abundances in axisymmetric accretion disk models around active galactic nuclei (AGNs) within 100 pc using simple radial and vertical density and temperature distributions motivated by more detailed physical models. We explore the effects of X-ray irradiation and cosmic-ray ionization on the spatial distribution of the molecular abundances of CO, CN, CS, HCN, HCO{sup +}, HC{sub 3}N, C{sub 2}H, and c-C{sub 3}H{sub 2} using a variety of plausible disk structures. These simple models have molecular regions with an X-ray-dominated region layer, a midplane without the strong influence of X-rays, and a high-temperature region in the inner portion with moderate X-ray flux where families of polyynes (C{sub n}H{sub 2}) and cyanopolyynes can be enhanced. For the high midplane density disks we explore, we find that cosmic rays produced by supernovae do not significantly affect the regions unless the star formation efficiency significantly exceeds that of the Milky Way. We highlight molecular abundance observations and ratios that may distinguish among theoretical models of the density distribution in AGN disks. Finally, we assess the importance of the shock crossing time and the accretion time relative to the formation time for various chemical species. Vertical column densities are tabulated for a number of molecular species at both the characteristic shock crossing time and steady state. Although we do not attempt to fit any particular system or set of observations, we discuss our models and results in the context of the nearby AGN NGC 1068.
Empat Model Aproksimasi Binomial Harga Saham Model black-Scholes
Directory of Open Access Journals (Sweden)
Abdul Aziz
2009-11-01
Full Text Available Kami akan menyajikan empat bentuk nilai parameter-parameter u, d, dan p dalam model Binomial harga saham, yang dihasilkan dengan menggunakan penyamaan ekspektasi dan variansi model diskrit dengan kontinu. Metode pertama menggunakan asumsi u . d = 1, yang mana metode ini dapat menghasilkan tiga bentuk solusi untuk parameter-parameter u, d, dan p dalam model Binomial harga saham. Metode kedua menggunakan asumsi p = 0,5. Dari kedua metode ini ternyata dapat dihasilkan empat bentuk solusi u, d, dan p yang berbeda dan akan dibandingkan hasilnya dalam pendekatan nilai option dalam model Binomial dengan model Black-Scholes.
Hairy black holes in the general Skyrme model
Adam, C; Shnir, Ya; Wereszczynski, A
2016-01-01
We study the existence of hairy black holes in the generalized Einstein-Skyrme model. It is proven that in the BPS model limit there are no hairy black hole solutions, although the model admits gravitating (and flat space) solitons. Furthermore, we find strong evidence that a necessary condition for the existence of black holes with Skyrmionic hair is the inclusion of the Skyrme term $\\mathcal{L}_4$. As an example, we show that there are no hairy black holes in the $\\mathcal{L}_2+\\mathcal{L}_6+\\mathcal{L}_0$ model and present a new kind of black hole solutions with compact Skyrmion hair in the $\\mathcal{L}_4+\\mathcal{L}_6+\\mathcal{L}_0$ model.
Black hole thermalization rate from brane anti-brane model
Lifschytz, G
2004-01-01
We develop the quasi-particle picture for Schwarzchild and far from extremal black holes. We show that the thermalization equations of the black hole is recovered from the model of branes and anti-branes. This can also be viewed as a field theory explanation of the relationship between area and entropy for these black holes. As a by product the annihilation rate of branes and anti-branes is computed.
Black hole thermalization rate from brane anti-brane model
Energy Technology Data Exchange (ETDEWEB)
Lifschytz, Gilad E-mail: giladl@research.haifa.ac.il
2004-08-01
We develop the quasi-particle picture for Schwarzchild and far from extremal black holes. We show that the thermalization equations of the black hole is recovered from the model of branes and anti-branes. This can also be viewed as a field theory explanation of the relationship between area and entropy for these black holes. As a by product the annihilation rate of branes and anti-branes is computed. (author)
Black hole spectroscopy from Loop Quantum Gravity models
Barrau, A.; Cao, Xiangyu; Noui, Karim; Perez, Alejandro
2015-01-01
Using Monte Carlo simulations, we compute the integrated emission spectra of black holes in the framework of Loop Quantum Gravity (LQG). The black hole emission rates are governed by the entropy whose value, in recent holographic loop quantum gravity models, was shown to agree at leading order with the Bekenstein-Hawking entropy. Quantum corrections depend on the Barbero-Immirzi parameter $\\gamma$. Starting with black holes of initial horizon area $A \\sim 10^2$ in Planck units, we present the...
A geometric crescent model for black hole images
Kamruddin, Ayman Bin; Dexter, Jason
2013-01-01
The Event Horizon Telescope (EHT), a global very long baseline interferometry array operating at millimetre wavelengths, is spatially resolving the immediate environments of black holes for the first time. The current observations of the Galactic center black hole, Sagittarius A* (Sgr A*), and M87 have been interpreted in terms of either geometric models (e.g., a symmetric Gaussian) or detailed calculations of the appearance of black hole accretion flows. The former are not physically motivat...
Black Holes in Pseudobulges: demography and models
Shankar, F; Mathur, S; Bernardi, M; Bournaud, F
2012-01-01
There is mounting evidence that a significant fraction of Black Holes (BHs) today live in late-type galaxies, including bulge-less galaxies and those hosting pseudobulges, and are significantly undermassive with respect to the scaling relations followed by their counterpart BHs in classical bulges of similar stellar (or even bulge) mass. Here we discuss the predictions of two state-of-the-art hierarchical galaxy formation models in which BHs grow via mergers and, in one, also via disk instability. Our aim is to understand if the wealth of new data on local BH demography is consistent with standard models. We follow the merger trees of representative subsamples of BHs and compute the fractional contributions of different processes to the final BH mass. We show that the model in which BHs always closely follow the growth of their host bulges, also during late disk instabilities (i.e., bars), produces too narrow a distribution of BHs at fixed stellar mass to account for the numerous low-mass BHs now detected in ...
Perturbative methods of solution for black holes and black strings in braneworld models
Sahabandu, Chetiya
In this thesis we use perturbative methods to solve the gravitational field equations to construct solutions that describe black branes in Randall-Sundrum (RS) and Arkani-Hamed - Dimopoulos - Dvali (ADD) braneworld models. In the ADD model we consider a black hole localized on the visible brane with a hori-zon radius smaller than the compactified dimension and calculate the corrections due to the compactification. Performing a similar calculation in the RS model we show that the existence of a black hole implies an asymptotic spacetime that depends on half-integer powers of the mass. We also construct solutions that describe black branes in Einstein-Gauss-Bonnet (EGB) gravity. In all cases we calculate important thermodynamical properties and investigate the stability of the solutions.
The gross theory model for neutrino-nucleus cross-section
International Nuclear Information System (INIS)
The nuclear gross theory, originally formulated by Takahashi and Yamada (1969 Prog. Theor. Phys. 41 1470) for the β-decay, is applied to the electronic-neutrino nucleus reactions, employing a more realistic description of the energetics of the Gamow-Teller resonances. The model parameters are gauged from the most recent experimental data, both for β--decay and electron capture, separately for even-even, even-odd, odd-odd and odd-even nuclei. The numerical estimates for neutrino-nucleus cross-sections agree fairly well with previous evaluations done within the framework of microscopic models. The formalism presented here can be extended to the heavy nuclei mass region, where weak processes are quite relevant, which is of astrophysical interest because of its applications in supernova explosive nucleosynthesis
Black hole Skyrmion in a generalized Skyrme model
Gudnason, Sven Bjarke; Sawado, Nobuyuki
2016-01-01
We study a Skyrme-like model with the Skyrme term and a sixth-order derivative term as higher-order terms, coupled to gravity and we construct Schwarzschild black hole Skyrme hair. We find, surprisingly, that the sixth-order derivative term alone cannot stabilize the black hole hair solutions; the Skyrme term with a large enough coefficient is a necessity.
Mathematical Model of Neuronal Morphology: Prenatal Development of the Human Dentate Nucleus
Rajković, Katarina; Bačić, Goran; Ristanović, Dušan; Milošević, Nebojša T.
2014-01-01
The aim of the study was to quantify the morphological changes of the human dentate nucleus during prenatal development using mathematical models that take into account main morphometric parameters. The camera lucida drawings of Golgi impregnated neurons taken from human fetuses of gestational ages ranging from 14 to 41 weeks were analyzed. Four morphometric parameters, the size of the neuron, the dendritic complexity, maximum dendritic density, and the position of maximum density, were obtai...
Calculation of Energy Levels of Nucleus 127I in the Particle-Triaxial-Rotor Model
Institute of Scientific and Technical Information of China (English)
SONG Hui-Chao; LIU Yu-Xin; ZHANG Yu-Hu
2004-01-01
@@ Theoretical calculations have been performed for nucleus 127 I in the framework of the particle-triaxial-rotor model.The calculated results indicate that both the 5+2 and 7+2 bands are oblate deformed bands. Their configurations are associated with the πd5/2 [402] 52 and πg7/2[404] 72 orbitals and the strong mixing between them. Meanwhile a possible explanation of the strong mixing is given.
Study of proton-nucleus collisions at high energies based on the hydrodynamical model
International Nuclear Information System (INIS)
We study proton-nucleus collisions at high energies using the one-dimensional hydrodynamical model of Landau with special emphasis on the effect of the size of the target nucleus and of the magnitude of velocity of sound of excited hadronic matter. We convert a collision problem of a proton and a nucleus with a spherical shape into that of a proton and a one-dimensional nuclear tunnel whose length is determined from the average impact parameter. By extending the methods developed by Milekhin and Emelyanov, we obtain the solutions of the hydrodynamical equations of proton-nucleus collisions for arbitrary target tunnel length and arbitrary velocity of sound. The connection between these solutions and observable physical quantities is established as in the work of Cooper, Frye, and Schonberg. Extensive numerical analyses are made at E/sub lab/ = 200 GeV and for the velocity of sound u = 1/√3 of a relativistic ideal Bose gas and u = 1/(7.5)/sup 1/2/ of an interacting Bose gas. In order to compare proton-nucleus collisions with proton-proton collisions, all the analyses are made in the equal-velocity frame. We find the following results. (1) In comparing the number of secondary particles produced in p-A collisions N/sub p/A with those in p-p collisions N/sub p/p, while most of the excess of N/sub p/A over N/sub p/p is concentrated in the backward rapidity region, there exists also an increase of N/sub p/A with A in the forward rapidity region. This result is at variance with the predictions of the energy-flux-cascade model and of the coherent-production model. (2) The excess energies are contained exclusively in the backward region. We also find evidence for new phenomena in proton-nucleus collisions. (3) The existence of an asymmetry of average energies of secondary particles between forward and backward regions, in particular, >> for larger nuclear targets. Thus, energetic particles are predominantly produced in the backward region
A full annual cycle modeling framework for American black ducks
Robinson, Orin J.; McGowan, Conor; Devers, Patrick K.; Brook, Rodney W.; Huang, Min; Jones, Malcom; McAuley, Daniel G.; Zimmerman, Guthrie
2016-01-01
American black ducks (Anas rubripes) are a harvested, international migratory waterfowl species in eastern North America. Despite an extended period of restrictive harvest regulations, the black duck population is still below the population goal identified in the North American Waterfowl Management Plan (NAWMP). It has been hypothesized that density-dependent factors restrict population growth in the black duck population and that habitat management (increases, improvements, etc.) may be a key component of growing black duck populations and reaching the prescribed NAWMP population goal. Using banding data from 1951 to 2011 and breeding population survey data from 1990 to 2014, we developed a full annual cycle population model for the American black duck. This model uses the seven management units as set by the Black Duck Joint Venture, allows movement into and out of each unit during each season, and models survival and fecundity for each region separately. We compare model population trajectories with observed population data and abundance estimates from the breeding season counts to show the accuracy of this full annual cycle model. With this model, we then show how to simulate the effects of habitat management on the continental black duck population.
Modelling the Growth of Supermassive Black Holes in Cosmological Simulations
Muldrew, Stuart I; Power, Chris
2013-01-01
There is strong evidence that supermassive black holes reside in all galaxies that contain a stellar spheroid and their mass is tightly correlated with properties such as stellar bulge mass and velocity dispersion. There are also strong theoretical arguments that feedback from supermassive black holes plays an important role in shaping the high mass end of the galaxy mass function, hence to accurately model galaxies we also need to model the black holes. We present a comparison of two black hole growth models implemented within a large-scale, cosmological SPH simulation including star formation and feedback. One model is a modified Bondi-Hoyle prescription that grows black holes based on the smooth density of local gas, while the other is the recently proposed Accretion Disc Particle (ADP) method. This model swallows baryonic particles that pass within an accretion radius of the black hole and adds them to a subgrid accretion disc. Black holes are then grown by material from this disc. We find that both model...
International Nuclear Information System (INIS)
The research of nuclear reactions is necessary to identify the specific characteristics of nucleus and it is the most effective experimental method up to now. However, in order to explain the properties of nuclear structures, in addition to the study of the nuclear reactions, nuclear structure models to explain experimental dat and its theory must be used. There are many nuclear structure models to solve those properties of nucleus. This paper presents a collective model application to identify some of rotational bands and vibrational bands of 152 Sm and 152Gd nucleus which result from beta decay of 152Eu source the. (author)
The Mass of the Black Hole in Arp 151 from Bayesian Modeling of Reverberation Mapping Data
Brewer, Brendon J; Pancoast, Anna; Barth, Aaron J; Bennert, Vardha N; Bentz, Misty C; Filippenko, Alexei V; Greene, Jenny E; Malkan, Matthew A; Woo, Jong-Hak
2011-01-01
Supermassive black holes are believed to be ubiquitous at the centers of galaxies. Measuring their masses is extremely challenging yet essential for understanding their role in the formation and evolution of cosmic structure. We present a direct measurement of the mass of a black hole in an active galactic nucleus (Arp 151) based on the motion of the gas responsible for the broad emission lines. By analyzing and modeling spectroscopic and photometric time series, we find that the gas is well described by a disk or torus with an average radius of 3.99 +- 1.25 light days and an opening angle of 68.9 (+21.4, -17.2) degrees, viewed at an inclination angle of 67.8 +- 7.8 degrees (that is, closer to face-on than edge-on). The black hole mass is inferred to be 10^(6.51 +- 0.28) solar masses. The method is fully general and can be used to determine the masses of black holes at arbitrary distances, enabling studies of their evolution over cosmic time.
Black hole spectroscopy from loop quantum gravity models
Barrau, Aurelien; Cao, Xiangyu; Noui, Karim; Perez, Alejandro
2015-12-01
Using Monte Carlo simulations, we compute the integrated emission spectra of black holes in the framework of loop quantum gravity (LQG). The black hole emission rates are governed by the entropy whose value, in recent holographic loop quantum gravity models, was shown to agree at leading order with the Bekenstein-Hawking entropy. Quantum corrections depend on the Barbero-Immirzi parameter γ . Starting with black holes of initial horizon area A ˜102 in Planck units, we present the spectra for different values of γ . Each spectrum clearly decomposes into two distinct parts: a continuous background which corresponds to the semiclassical stages of the evaporation and a series of discrete peaks which constitutes a signature of the deep quantum structure of the black hole. We show that γ has an effect on both parts that we analyze in detail. Finally, we estimate the number of black holes and the instrumental resolution required to experimentally distinguish between the considered models.
A geometric crescent model for black hole images
Kamruddin, Ayman Bin
2013-01-01
The Event Horizon Telescope (EHT), a global very long baseline interferometry array operating at millimetre wavelengths, is spatially resolving the immediate environments of black holes for the first time. The current observations of the Galactic center black hole, Sagittarius A* (Sgr A*), and M87 have been interpreted in terms of either geometric models (e.g., a symmetric Gaussian) or detailed calculations of the appearance of black hole accretion flows. The former are not physically motivated, while the latter are subject to large systematic uncertainties. Motivated by the dominant relativistic effects of Doppler beaming and gravitational lensing in many calculations, we propose a geometric crescent model for black hole images. We show that this simple model provides an excellent statistical description of the existing EHT data of Sgr A* and M87, superior to other geometric models for Sgr A*. It also qualitatively matches physically predicted models, bridging accretion theory and observation. Based on our r...
Indian Academy of Sciences (India)
W. X. Zhong
2014-09-01
In this paper, we use the canonical ensemble model to discuss the radiation of a Schwarzschild–de Sitter black hole on the black hole horizon. Using this model, we calculate the probability distribution from function of the emission shell. And the statistical meaning which compare with the distribution function is used to investigate the black hole tunnelling radiation spectrum.We also discuss the mechanism of information flowing from the black hole.
Framework for developing a hierarchical model of reward focusing on the nucleus accumbens.
Smith, Wesley; Nair, Satish S; Xu, Dong; Nair, Jyotsna; Beitman, Bernard
2004-01-01
Computational modeling using GENESIS platform has led to advances in fabricating a model to test the influence of molecular/proteomic adaptations on behavior due to reward. The nucleus accumbens is an area of the brain that processes information from other parts of the brain and is an integral element of the 'reward pathway' in the brain. A simplified model of the accumbens using one neuron is developed as part of a larger effort to study reward and chemical dependency with a focus on cocaine addiction. A preliminary model of a biologically realistic neuron was developed with inhibitory and excitatory afferents as well as intrasynapse dynamics. The neuron displayed characteristic behavior of a neuron found in the nucleus accumbens including bistability. The neuron has afferents from other neurons via dendrites which carry the inputs relating to behavioral aspects and to learning. To add behavioral aspects to the model, a methodology is developed to model contexts and their reinforcing effects on behavior, similar to cocaine addiction. Results using both the biological and behavioral modeling are encouraging for this preliminary model. PMID:17271623
Evaluation of black carbon estimations in global aerosol models
Koch, D.; Schulz, M.; McNaughton, C.; Spackman, J.R.; Balkanski, Y.; Bauer, S.; Krol, M.C.
2009-01-01
We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentr
Near-horizon states of black holes and Calogero models
Indian Academy of Sciences (India)
B Basu-Mallick; Pijush K Ghosh; Kumar S Gupta
2004-03-01
We find self-adjoint extensions of the rational Calogero model in the presence of the harmonic interaction. The corresponding eigenfunctions may describe the near-horizon quantum states of certain types of black holes.
Habitat suitability index model for black bear (Ursus americanus)
US Fish and Wildlife Service, Department of the Interior — This descriptive model applies only to black bear in the coastal forests and adjacent vegetative communities, which extend from Afognak Island and the shores of...
The dynamical model and quantization of the Schwarzschild black hole
Institute of Scientific and Technical Information of China (English)
2008-01-01
The mass of the Schwarzschild black hole, an observable quantity, is defined as a dynamical variable, while the corresponding conjugate is considered as a general- ized momentum. Then a two-dimensional phase space is composed of the two variables. In the two-dimensional phase space, a harmonic oscillator model of the Schwarzschild black hole is obtained by a canonical transformation. By this model, the mass spectrum of the Schwarzschild black hole is firstly obtained. Further the horizon area operator, quantum area spectrum and entropy are obtained in the Fock representation. Lastly, the wave function of the horizon area is derived also.
Compound nucleus formation probability PCN defined within the dynamical cluster-decay model
Chopra, Sahila; Kaur, Arshdeep; Gupta, Raj K.
2015-01-01
With in the dynamical cluster-decay model (DCM), the compound nucleus fusion/ formation probability PCN is defined for the first time, and its variation with CN excitation energy E* and fissility parameter χ is studied. In DCM, the (total) fusion cross section σfusion is sum of the compound nucleus (CN) and noncompound nucleus (nCN) decay processes, each calculated as the dynamical fragmentation process. The CN cross section σCN is constituted of the evaporation residues (ER) and fusion-fission (ff), including the intermediate mass fragments (IMFs), each calculated for all contributing decay fragments (A1, A2) in terms of their formation and barrier penetration probabilities P0 and P. The nCN cross section σnCN is determined as the quasi-fission (qf) process where P0=1 and P is calculated for the entrance channel nuclei. The calculations are presented for six different target-projectile combinations of CN mass A~100 to superheavy, at various different center-of-mass energies with effects of deformations and orientations of nuclei included in it. Interesting results are that the PCN=1 for complete fusion, but PCN <1 or ≪1 due to the nCN conribution, depending strongly on both E* and χ.
Compound nucleus formation probability PCN defined within the dynamical cluster-decay model
Directory of Open Access Journals (Sweden)
Chopra Sahila
2015-01-01
Full Text Available With in the dynamical cluster-decay model (DCM, the compound nucleus fusion/ formation probability PCN is defined for the first time, and its variation with CN excitation energy E* and fissility parameter χ is studied. In DCM, the (total fusion cross section σfusion is sum of the compound nucleus (CN and noncompound nucleus (nCN decay processes, each calculated as the dynamical fragmentation process. The CN cross section σCN is constituted of the evaporation residues (ER and fusion-fission (ff, including the intermediate mass fragments (IMFs, each calculated for all contributing decay fragments (A1, A2 in terms of their formation and barrier penetration probabilities P0 and P. The nCN cross section σnCN is determined as the quasi-fission (qf process where P0=1 and P is calculated for the entrance channel nuclei. The calculations are presented for six different target-projectile combinations of CN mass A~100 to superheavy, at various different center-of-mass energies with effects of deformations and orientations of nuclei included in it. Interesting results are that the PCN=1 for complete fusion, but PCN <1 or ≪1 due to the nCN conribution, depending strongly on both E* and χ.
Giusti, Carlotta
2014-01-01
The analysis of quasielastic neutrino and antineutrino-nucleus scattering cross sections requires relativistic theoretical descriptions also accounting for the role of final-state interactions (FSI). In the relativistic Green's function (RGF) model FSI are described by a complex optical potential where the imaginary part recovers the contribution of final-state channels that are not included in other models based on the impulse approximation. The RGF results are compared with the data recently published by the MiniBooNE and MINER$\
Black Hole Evaporation in a Noncommutative Charged Vaidya Model
Sharif, M.; Javed, Wajiha
2012-01-01
The aim of this paper is to study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstr$\\ddot{o}$m-like solution of this model which leads to an exact $(t-r)$ dependent metric. The behavior of temporal component of this metric and the corresponding Hawking temperature is investigated. The results are shown in the form of grap...
BTZ Black Hole Entropy and the Turaev-Viro model
Geiller, Marc
2013-01-01
We show the explicit agreement between the derivation of the Bekenstein-Hawking entropy of a Euclidean BTZ black hole from the point of view of spin foam models and canonical quantization. This is done by considering a graph observable (corresponding to the black hole horizon) in the Turaev-Viro state sum model, and then analytically continuing the resulting partition function to negative values of the cosmological constant.
Release model for black liquor droplet; Mustalipeaepisaran vapautumismalli
Energy Technology Data Exchange (ETDEWEB)
Saastamoinen, J. [VTT Energy, Espoo (Finland)
1997-10-01
The release of sodium, potassium, chlorine and sulphur from black liquor droplets during pyrolysis, combustion and gasification is studied by modelling work. A model for drying, pyrolysis and swelling of black liquor has been developed earlier. A submodel for the release of sulphur, which takes place at temperatures below 500 deg C has been incorporated to this model. A previous model for the combustion and gasification of char particles has been further developed to account for the effect of sodium, potassium and chlorine. A model for the release of these components as function of time has been developed. (orig.)
Modeling the nucleus and jets of comet 81P/Wild 2 based on the Stardust encounter data.
Sekanina, Zdenek; Brownlee, Donald E; Economou, Thanasis E; Tuzzolino, Anthony J; Green, Simon F
2004-06-18
We interpret the nucleus properties and jet activity from the Stardust spacecraft imaging and the onboard dust monitoring system data. Triangulation of 20 jets shows that 2 emanate from the nucleus dark side and 16 emanate from sources that are on slopes where the Sun's elevation is greater than predicted from the fitted triaxial ellipsoid. Seven sources, including five in the Mayo depression, coincide with relatively bright surface spots. Fitting the imaged jets, the spikelike temporal distribution of dust impacts indicates that the spacecraft crossed thin, densely populated sheets of particulate ejecta extending from small sources on the rotating nucleus, consistent with an emission cone model.
Holographic shell model: Stack data structure inside black holes?
Davidson, Aharon
2014-03-01
Rather than tiling the black hole horizon by Planck area patches, we suggest that bits of information inhabit, universally and holographically, the entire black core interior, a bit per a light sheet unit interval of order Planck area difference. The number of distinguishable (tagged by a binary code) configurations, counted within the context of a discrete holographic shell model, is given by the Catalan series. The area entropy formula is recovered, including Cardy's universal logarithmic correction, and the equipartition of mass per degree of freedom is proven. The black hole information storage resembles, in the count procedure, the so-called stack data structure.
A Quantum Model of Schwarzschild Black Hole Evaporation
Cruz Muñoz, José Luis; Mikovic, A.; Navarro Salas, José
1996-01-01
We construct a one-loop effective metric describing the evaporation phase of a Schwarzschild black hole in a spherically symmetric null-dust model. This is achieved by quantising the Vaidya solution and by chosing a time dependent quantum state. This state describes a black hole which is initially in thermal equilibrium and then the equilibrium is switched off, so that the black hole starts to evaporate, shrinking to a zero radius in a finite proper time. The naked singularity appears, and th...
A Liquid Model Analogue for Black Hole Thermodynamics
Hochberg, D; Hochberg, David; Pérez-Mercader, Juan
1996-01-01
We are able to characterize a 2--dimensional classical fluid sharing some of the same thermodynamic state functions as the Schwarzschild black hole. This phenomenological correspondence between black holes and fluids is established by means of the model liquid's pair-correlation function and the two-body atomic interaction potential. These latter two functions are calculated exactly in terms of the black hole internal (quasilocal) energy and the isothermal compressibility. We find the existence of a ``screening" like effect for the components of the liquid.
Black hole evaporation in a noncommutative charged Vaidya model
Energy Technology Data Exchange (ETDEWEB)
Sharif, M., E-mail: msharif.math@pu.edu.pk; Javed, W. [University of the Punjab, Department of Mathematics (Pakistan)
2012-06-15
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstroem-like solution of this model, which leads to an exact (t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Black Hole Evaporation in a Noncommutative Charged Vaidya Model
Sharif, M
2012-01-01
The aim of this paper is to study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstr$\\ddot{o}$m-like solution of this model which leads to an exact $(t-r)$ dependent metric. The behavior of temporal component of this metric and the corresponding Hawking temperature is investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of the charged massive particles through the quantum horizon. It is found that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from maximum value to zero. It is mentioned here that the final stage of black hole evaporation turns out to be a naked singularity.
Black hole evaporation in a noncommutative charged Vaidya model
Sharif, M.; Javed, W.
2012-06-01
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordström-like solution of this model, which leads to an exact ( t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Black hole evaporation in a noncommutative charged Vaidya model
International Nuclear Information System (INIS)
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordström-like solution of this model, which leads to an exact (t − r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Lovelock black hole thermodynamics in a string cloud model
Lee, Tae-Hun; Ghosh, Sushant G.; Maharaj, Sunil D.(Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag 54001, 4000, Durban, South Africa); Baboolal, Dharmanand
2015-01-01
The Lovelock theory is an extension of general relativity to higher dimensions. We study the Lovelock black hole for a string cloud model in arbitrary dimensional spacetime, and in turn also analyze its thermodynamical properties. Indeed, we compute the mass, temperature and entropy of the black hole and also perform a thermodynamical stability analysis. The phase structure suggests that the Hawking-Page phase transition is achievable. It turns out that the presence of the Lovelock terms and/...
Comparing of the binomial model and the black-scholes model for options pricing
Lazarova, Limonka; Jolevska-Tuneska, Biljana; Atanasova-Pacemska, Tatjana
2014-01-01
In this paper will be considered the simple binomial model with one and more periods. It will be given the correspondence between binomial model and the Black-Scholes model for option pricing and also will be shown that the binomial model is more simple then the continuous Black- Scholes model from pedagogical point of view.
Chaos in Matrix Models and Black Hole Evaporation
Berkowitz, Evan; Maltz, Jonathan
2016-01-01
Is the evaporation of a black hole described by a unitary theory? In order to shed light on this question ---especially aspects of this question such as a black hole's negative specific heat---we consider the real-time dynamics of a solitonic object in matrix quantum mechanics, which can be interpreted as a black hole (black zero-brane) via holography. We point out that the chaotic nature of the system combined with the flat directions of its potential naturally leads to the emission of D0-branes from the black brane, which is suppressed in the large $N$ limit. Simple arguments show that the black zero-brane, like the Schwarzschild black hole, has negative specific heat, in the sense that the temperature goes up when it evaporates by emitting D0-branes. While the largest Lyapunov exponent grows during the evaporation, the Kolmogorov-Sinai entropy decreases. These are consequences of the generic properties of matrix models and gauge theory. Based on these results, we give a possible geometric interpretation of...
Bohr's Semiclassical Model of the Black Hole Thermodynamics
Directory of Open Access Journals (Sweden)
Panković, V.
2008-06-01
Full Text Available We propose a simple procedure for evaluating the main attributes of a Schwarzschild's black hole: Bekenstein-Hawking entropy, Hawking temperature and Bekenstein's quantization of the surface area. We make use of the condition that the circumference of a great circle on the black hole horizon contains finite and whole number of the corresponding reduced Compton's wavelength. It is essentially analogous to Bohr's quantization postulate in Bohr's atomic model interpreted by de Broglie's relation. It implies the standard meaning of the black hole entropy corresponding to surface of the quantum variation of the great circles on the black hole horizon surface area. We present black hole radiation in the form conceptually analogous to Bohr's postulate on the photon emission by discrete quantum jump of the electron within the Old quantum theory. This enables us, in accordance with Heisenberg's uncertainty relation and Bohr's correspondence principle, to make a rough estimate of the time interval for black hole evaporation, which turns out very close to time interval predicted by the standard Hawking's theory. Our calculations confirm Bekenstein's semiclassical result for the energy quantization, in variance with Frasca's (2005 calculations. Finally we speculate about the possible source-energy distribution within the black hole horizon.
A computer code for calculations in the algebraic collective model of the atomic nucleus
Welsh, T A
2016-01-01
A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1,1) x SO(5) dynamical group. This, in particular, obviates the use of coefficients of fractional parentage. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [pi x q x pi]_0 and [pi x pi]_{LM}, where q_M are the model's quadrupole moments, and pi_N are corresponding conjugate momenta (-2>=M,N<=2). The code also provides ready access to SO(3)-reduced SO(5) Clebsch-Gordan coefficients through data files provided with the code.
A model of dust fragmentation in near-nucleus jet-like features on Comet P/Halley
Konno, Ichishiro; Huebner, W. F.; Boice, D. C.
1993-01-01
A model for dusty gas flows and dust fragmentation in cometary atmospheres is developed and applied to interpret the dust intensity profiles near the nucleus of Comet P/Halley. It is found that fragmentation is not the only physical mechanism for explaining the dust intensity profiles from the 1/z dependence in the region about 1 to 40 km from the nucleus. A combination of the geometric effect and dust fragmentation is a likely explanation for the profiles.
Ghazvini, M; Salehi, N; Rajabi, A. A.
2014-01-01
In this paper, the Schr\\"odinger equation for 6-body system is studied. We solved this equation for lithium nucleus by using supersymmetry method with the specific potentials. These potentials are Yukawa potential, the generalized Yukawa potential and Hellmann potential. The results of our model for all calculations show that the ground state binding energy of Lithium nucleus with these potentials are very close to the ones obtained in experiments.
A geometric crescent model for black hole images
Kamruddin, Ayman Bin; Dexter, Jason
2013-09-01
The Event Horizon Telescope (EHT), a global very long baseline interferometry array operating at millimetre wavelengths, is spatially resolving the immediate environments of black holes for the first time. The current observations of the Galactic centre black hole, Sagittarius A* (Sgr A*), and M87 have been interpreted in terms of either geometric models (e.g. a symmetric Gaussian) or detailed calculations of the appearance of black hole accretion flows. The former are not physically motivated, while the latter are subject to large systematic uncertainties. Motivated by the dominant relativistic effects of Doppler beaming and gravitational lensing in many calculations, we propose a geometric crescent model for black hole images. We show that this simple model provides an excellent statistical description of the existing EHT data of Sgr A* and M87, superior to other geometric models for Sgr A*. It also qualitatively matches physically predicted models, bridging accretion theory and observation. Based on our results, we make predictions for the detectability of the black hole shadow, a signature of strong gravity, in future observations.
Qubit Transport Model for Unitary Black Hole Evaporation without Firewalls
Osuga, Kento
2016-01-01
We give an explicit toy qubit transport model for transferring information from the gravitational field of a black hole to the Hawking radiation by a continuous unitary transformation of the outgoing radiation and the black hole gravitational field. The model has no firewalls or other drama at the event horizon and fits the set of six physical constraints that Giddings has proposed for models of black hole evaporation. It does utilize nonlocal qubits for the gravitational field but assumes that the radiation interacts locally with these nonlocal qubits, so in some sense the nonlocality is confined to the gravitational sector. Although the qubit model is too crude to be quantitively correct for the detailed spectrum of Hawking radiation, it fits qualitatively with what is expected.
Enhancement of φ Mesons in Relativistic Nucleus-Nucleus Collisions
Institute of Scientific and Technical Information of China (English)
2002-01-01
The фmeson production in relativistic nucleus-nucleus collisions is investigated systematically usinga hadron-string cascade model LUCIAE. Within the framework of the model and relying on the collective
Generating primordial black holes via hilltop-type inflation models
International Nuclear Information System (INIS)
It has been shown that black holes would have formed in the early Universe if, on any given scale, the spectral amplitude of the cosmic microwave background exceeds Pζ∼10-4. This value is within the bounds allowed by astrophysical phenomena for the small scale spectrum of the cosmic microwave background, corresponding to scales which exit the horizon at the end of slow-roll inflation. Previous work by Kohri et al. (2007) showed that for black holes to form from a single field model of inflation, the slope of the potential at the end of inflation must be flatter than it was at horizon exit. In this work we show that a phenomenological hilltop model of inflation, satisfying the Kohri et al. criteria, could lead to the production of black holes, if the power of the inflaton self-interaction is less than or equal to 3, with a reasonable number or e-folds. We extend our analysis to the running mass model, and confirm that this model results in the production of black holes, and by using the latest WMAP year 5 bounds on the running of the spectral index, and the black hole constraint we update the results of Leach et al. (2000) excluding more of parameter space.
Symmetries and solvable models for evaporating 2D black holes
Cruz Muñoz, José Luis; Navarro-Salas, José; Navarro Navarro, Miguel; Talavera, C. F.
1997-01-01
We study the evaporation process of a 2D black hole in thermal equilibrium when the ingoing radiation is suddenly switched off. We also introduce global symmetries of generic 2D dilaton gravity models which generalize the extra symmetry of the CGHS model. © Elsevier Science B.V
Modeling gravitational radiation from coalescing binary black holes
Baker, J; Loustó, C O; Takahashi, R
2002-01-01
With the goal of bringing theory, particularly numerical relativity, to bear on an astrophysical problem of critical interest to gravitational wave observers we introduce a model for coalescence radiation from binary black hole systems. We build our model using the "Lazarus approach", a technique that bridges far and close limit approaches with full numerical relativity to solve Einstein equations applied in the truly nonlinear dynamical regime. We specifically study the post-orbital radiation from a system of equal-mass non-spinning black holes, deriving waveforms which indicate strongly circularly polarized radiation of roughly 3% of the system's total energy and 12% of its total angular momentum in just a few cycles. Supporting this result we first establish the reliability of the late-time part of our model, including the numerical relativity and close-limit components, with a thorough study of waveforms from a sequence of black hole configurations varying from previously treated head-on collisions to rep...
Effective-one-body modeling of precessing black hole binaries
Taracchini, Andrea; Babak, Stanislav; Buonanno, Alessandra
2016-03-01
Merging black hole binaries with generic spins that undergo precessional motion emit complicated gravitational-wave signals. We discuss how such waveforms can be accurately modeled within an effective-one-body approach by (i) exploiting the simplicity of the signals in a frame that corotates with the orbital plane of the binary and (ii) relying on an accurate model of nonprecessing black hole binaries. The model is validated by extensive comparisons to 70 numerical relativity simulations of precessing black hole binaries and can generate inspiral-merger-ringdown waveforms for mass ratios up to 100 and any spin configuration. This work is an essential tool for studying and characterizing candidate gravitational-wave events in science runs of advanced LIGO.
Komossa, S
2008-01-01
We consider the consequences of gravitational wave recoil for unified models of active galactic nuclei (AGNs). Spatial oscillations of supermassive black holes (SMBHs) around the cores of galaxies following gravitational wave (GW) recoil imply that the SMBHs spend a significant fraction of time off-nucleus, at scales beyond that of the molecular obscuring torus. Assuming reasonable distributions of recoil velocities, we compute the off-core timescale of (intrinsically type-2) quasars. We find that roughly one-half of major mergers result in a SMBH being displaced beyond the torus for a time of 30 Myr or more, comparable to quasar activity timescales. Since major mergers are most strongly affected by GW recoil, our results imply a deficiency of type 2 quasars in comparison to Seyfert 2 galaxies. Other consequences of the recoil oscillations for the observable properties of AGNs are also discussed.
Efficient hedging in general Black-Scholes model
Kyong-Hui Kim; Myong-Guk Sin
2013-01-01
An investor faced with a contingent claim may eliminate risk by perfect hedging, but as it is often quite expensive, he seeks partial hedging (quantile hedging or efficient hedging) that requires less capital and reduces the risk. Efficient hedging for European call option was considered in the standard Black-Scholes model with constant drift and volatility coefficients. In this paper we considered the efficient hedging for European call option in general Black-Scholes model $dX_t=X_t(m(t)dt+...
A Dynamical model for non-geometric quantum black holes
Spallucci, Euro
2016-01-01
It has been recently proposed that quantum black holes can be described as N-graviton Bose-Einstein condensates. In this picture the quantum properties of BHs "... can be understood in terms of the single number N". However, so far, the dynamical origin of the occupational number N has not been specified. This description is alternative to the usual one, where black holes are believed to be well described geometrically even at the quantum level. In this paper we pursue the former point of view and develop a non-geometrical dynamical model of quantum black holes (BHs). In our model the occupational number N is proportional to the principal quantum number n of a Planckian harmonic oscillator. The so-called "classicalization" corresponds to the large-n limit, where the Schwarzschild horizon is recovered.
Retrograde versus Prograde Models of Accreting Black Holes
Directory of Open Access Journals (Sweden)
David Garofalo
2013-01-01
Full Text Available There is a general consensus that magnetic fields, accretion disks, and rotating black holes are instrumental in the generation of the most powerful sources of energy in the known universe. Nonetheless, because magnetized accretion onto rotating black holes involves both the complications of nonlinear magnetohydrodynamics that currently cannot fully be treated numerically, and uncertainties about the origin of magnetic fields that at present are part of the input, the space of possible solutions remains less constrained. Consequently, the literature still bears witness to the proliferation of rather different black hole engine models. But the accumulated wealth of observational data is now sufficient to meaningfully distinguish between them. It is in this light that this critical paper compares the recent retrograde framework with standard “spin paradigm” prograde models.
On black hole solutions in model with anisotropic fluid
Dehnen, H; Melnikov, V N
2003-01-01
A family of spherically symmetric solutions in the model with 1-component anisotropic fluid is considered. The metric of the solution depends on a parameter q > 0 relating radial pressure and the density and contains n -1 parameters corresponding to Ricci-flat ``internal space'' metrics. For q = 1 and certain equations of state the metric coincides with the metric of black brane solutions in the model with antisymmetric form. A family of black hole solutions corresponding to natural numbers q = 1,2, ... is singled out. Certain examples of solutions (e.g. containing for q =1 Reissner-Nordstr\\"{o}m, M2 and M5 black brane metrics) are considered. The post-Newtonian parameters beta and gamma corresponding to the 4-dimensional section of the metric are calculated.
Black hole spectroscopy from Loop Quantum Gravity models
Barrau, Aurelien; Noui, Karim; Perez, Alejandro
2015-01-01
Using Monte Carlo simulations, we compute the integrated emission spectra of black holes in the framework of Loop Quantum Gravity (LQG). The black hole emission rates are governed by the entropy whose value, in recent holographic loop quantum gravity models, was shown to agree at leading order with the Bekenstein-Hawking entropy. Quantum corrections depend on the Barbero-Immirzi parameter $\\gamma$. Starting with black holes of initial horizon area $A \\sim 10^2$ in Planck units, we present the spectra for different values of $\\gamma$. Each spectrum clearly decomposes in two distinct parts: a continuous background which corresponds to the semi-classical stages of the evaporation and a series of discrete peaks which constitutes a signature of the deep quantum structure of the black hole. We show that $\\gamma$ has an effect on both parts that we analyze in details. Finally, we estimate the number of black holes and the instrumental resolution required to experimentally distinguish between the considered models.
Habitat suitability index models: Black-shouldered kite
Energy Technology Data Exchange (ETDEWEB)
Faanes, C.A.; Howard, R.J.
1987-01-01
The black-shouldered kite inhabits a disjunct range extending from California, Texas, and south intermittently to Chile and Argentina (American Ornithologists' Union 1983). Prior to the 1960's, this species occurred in low numbers across much of its range. Populations of black-shouldered kite have changed considerably within the limited area of its US range. Although considered common and widespread in California in the late 1800's, the species was largely extirpated from much of the state by the early 1900's. Since 1960, the population status and range of this raptor in North America have improved markedly. Today the black-shouldered kite in California is a common species of open and cultivated bottomland. The black-shouldered kite habitat suitability index (HSI) model is intended for use with the habitat evaluation procedures (HEP) developed by the US Fish and Wildlife Service (1980) for impact assessment and habitat management. The model was developed from a review and synthesis of existing information, and includes unpublished information that reflects the opinions of persons familiar with black-shouldered kite ecology. It is scaled to produce an index of habitat suitability between 0 (unsuitable habitat) and 1.0 (optimally suitable habitat). Assumptions used to develop the HSI model and guidelines for model application, including techniques for measuring model variables, are described. Model documentation is provided. This model is a hypothesis of species-habitat relations, not a statement of proven cause and effect. The model has not been field tested. 33 refs., 3 tabs.
P.N. Scriven; P.M.M. Bossuyt
2010-01-01
The aim of this study was to develop and use theoretical models to investigate the accuracy of the fluorescence in situ hybridization (FISH) technique in testing a single nucleus from a preimplantation embryo without the complicating effect of mosaicism. Mathematical models were constructed for thre
Meucci, Andrea
2015-01-01
We compare the results of the relativistic Green's function model with the experimental data of the charged-current inclusive differential neutrino-nucleus cross sections published by the T2K Collaboration. The model, which is able to describe both MINER$\
Modeling neutrino-nucleus interactions in the few-GeV regime
Jachowicz, Natalie
2011-01-01
Detecting neutrinos and extracting the information they bring along is an ambitions task that requires a detailed understanding of neutrino-nucleus interactions over a broad energy range. We present calculations for quasi-elastic neutrino-induced nucleon knockout reactions on atomic nuclei and neutrino-induced pion production reactions. In our models, final-state interactions are introduced using a relativistic multiple-scattering Glauber approximation (RMSGA) approach. For interactions at low incoming neutrino energies, long-range correlations are implemented by means of a continuum random phase approximation (CRPA) approach. As neutrinos are the only particles interacting solely by means of the weak interaction, they can reveal information about e.g. the structure of nuclei or the strange quark content of the nucleon that is difficult to obtain otherwise. We investigated these effects and present results for the sensitivity of neutrino interactions to the influence of the nucleon's strange quark sea.
Jump-Diffusion Models for Option Pricing versus the Black Scholes Model
Storeng, Håkon Båtnes
2014-01-01
In general, the daily logarithmic returns of individual stocks are not normally distributed. This poses a challenge when trying to compute the most accurate option prices. This thesis investigates three different models for option pricing, The Black Scholes Model (1973), the Merton Jump-Diffusion Model (1975) and the Kou Double-Exponential Jump-Diffusion Model (2002). The jump-diffusion models do not make the same assumption as the Black Scholes model regarding the behavior of the underlyi...
Models for solid-state transport: messenger RNA movement from nucleus to cytoplasm.
Agutter, P S
1994-09-01
This paper explores the idea that mRNAs are transported between their transcription and processing sites in the nucleus, and their translation and degradation sites in the cytoplasm, by a 'solid-state' process. The underlying assumption is that negligible quantities of mRNA and of mRNA precursors are in solution in vivo. Therefore, mRNA transport cannot be considered as movement in the aqueous phase of the cell. The main lines of experimental evidence supporting this 'solid-state' concept are summarized and related controversies are outlined. Three possible models for a solid-state transport mechanism are discussed: a direct transfer model, with receptors organized analogously to the components of a multienzyme complex; a motor-driven model, analogous to synaptic vesicle transport in axons; and an assembly-driven model which assumes net movement along a fibril resulting from differential activities at the poles. Qualitative evaluation indicates that each of these models has characteristic advantages and disadvantages. The possibility that other nucleocytoplasmic transport processes might operate by solid-state mechanisms is briefly discussed.
A computer code for calculations in the algebraic collective model of the atomic nucleus
Welsh, T. A.; Rowe, D. J.
2016-03-01
A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1 , 1) × SO(5) dynamical group. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code enables a wide range of model Hamiltonians to be analysed. This range includes essentially all Hamiltonians that are rational functions of the model's quadrupole moments qˆM and are at most quadratic in the corresponding conjugate momenta πˆN (- 2 ≤ M , N ≤ 2). The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [ π ˆ ⊗ q ˆ ⊗ π ˆ ] 0 and [ π ˆ ⊗ π ˆ ] LM. The code is made efficient by use of an analytical expression for the needed SO(5)-reduced matrix elements, and use of SO(5) ⊃ SO(3) Clebsch-Gordan coefficients obtained from precomputed data files provided with the code.
A toy model of black hole complementarity
Banerjee, Souvik; Bryan, Jan-Willem; Papadodimas, Kyriakos; Raju, Suvrat
2016-05-01
We consider the algebra of simple operators defined in a time band in a CFT with a holographic dual. When the band is smaller than the light crossing time of AdS, an entire causal diamond in the center of AdS is separated from the band by a horizon. We show that this algebra obeys a version of the Reeh-Schlieder theorem: the action of the algebra on the CFT vacuum can approximate any low energy state in the CFT arbitrarily well, but no operator within the algebra can exactly annihilate the vacuum. We show how to relate local excitations in the complement of the central diamond to simple operators in the band. Local excitations within the diamond are invisible to the algebra of simple operators in the band by causality, but can be related to complicated operators called "precursors". We use the Reeh-Schlieder theorem to write down a simple and explicit formula for these precursors on the boundary. We comment on the implications of our results for black hole complementarity and the emergence of bulk locality from the boundary.
A toy model of black hole complementarity
Banerjee, Souvik; Papadodimas, Kyriakos; Raju, Suvrat
2016-01-01
We consider the algebra of simple operators defined in a time band in a CFT with a holographic dual. When the band is smaller than the light crossing time of AdS, an entire causal diamond in the center of AdS is separated from the band by a horizon. We show that this algebra obeys a version of the Reeh-Schlieder theorem: the action of the algebra on the CFT vacuum can approximate any low energy state in the CFT arbitrarily well, but no operator within the algebra can exactly annihilate the vacuum. We show how to relate local excitations in the complement of the central diamond to simple operators in the band. Local excitations within the diamond are invisible to the algebra of simple operators in the band by causality, but can be related to complicated operators called "precursors". We use the Reeh-Schlieder theorem to write down a simple and explicit formula for these precursors on the boundary. We comment on the implications of our results for black hole complementarity and the emergence of bulk locality fr...
Black hole entropy in the O(N) model
Kabat, D; Strassler, M J
1995-01-01
We consider corrections to the entropy of a black hole from an O(N) invariant linear \\s-model. We obtain the entropy from a 1/N expansion of the partition function on a cone. The entropy arises from diagrams which are analogous to those introduced by Susskind and Uglum to explain black hole entropy in string theory. The interpretation of the \\sm entropy depends on scale. At short distances, it has a state counting interpretation, as the entropy of entanglement of the N fields \\pa. In the infrared, the effective theory has a single composite field \\s \\sim \\pa \\pa, and the state counting interpretation of the entropy is lost.
Generating Primordial Black Holes Via Hilltop-Type Inflation Models
Alabidi, Laila; Kohri, Kazunori
2009-01-01
It has been shown that black holes would have formed in the early Universe if, on any given scale, the spectral amplitude of the Cosmic Microwave Background (CMB) exceeds 10^(-4). This value is within the bounds allowed by astrophysical phenomena for the small scale spectrum of the CMB, corresponding to scales which exit the horizon at the end of slow-roll inflation. Previous work by Kohri et. al. (2007) showed that for black holes to form from a single field model of inflation, the slope of ...
The modified Black-Scholes model via constant elasticity of variance for stock options valuation
Edeki, S. O.; Owoloko, E. A.; Ugbebor, O. O.
2016-02-01
In this paper, the classical Black-Scholes option pricing model is visited. We present a modified version of the Black-Scholes model via the application of the constant elasticity of variance model (CEVM); in this case, the volatility of the stock price is shown to be a non-constant function unlike the assumption of the classical Black-Scholes model.
Active galactic nucleus torus models and the puzzling infrared spectrum of IRAS F10214+4724
Efstathiou, A; Verma, A; Siebenmorgen, R
2013-01-01
We present a revised model for the infrared emission of the hyperluminous infrared galaxy IRAS F10214+4724 which takes into account recent photometric data from Spitzer and Herschel that sample the peak of its spectral energy distribution. We first present and discuss a grid of smooth active galactic nucleus (AGN) torus models computed with the method of Efstathiou & Rowan-Robinson and demonstrate that the combination of these models and the starburst models of Efstathiou and coworkers, while able to give an excellent fit to the average spectrum of Seyfert 2s and spectra of individual type 2 quasars measured by Spitzer, fails to match the spectral energy distribution of IRAS F10214+4724. This is mainly due to the fact that the nuSnu distribution of the galaxy falls very steeply with increasing frequency (a characteristic that is usually indicative of heavy absorption by dust) but shows a silicate feature in emission. Such emission features are not expected in sources with optical/near-infrared type 2 AGN ...
Production cross sections of the superheavy nucleus 117 based on the dinuclear system model
Institute of Scientific and Technical Information of China (English)
ZHAO Wei-Juan; ZHANG Yong-Qi; WANG Hua-Lei; SONG Li-Tao; LI Lu-Lu
2010-01-01
Within the framework of the dinuclear system model,the capture of two colliding nuclei,and the formation and de-excitation process of a compound nucleus are described by using an empirical coupled channel model,solving the master equation numerically and the statistical evaporation model,respectively.In the process of heavy-ion capture and fusion to synthesize superheavy nuclei,the barrier distribution func-tion is introduced and averaging collision orientations are considered.Based on this model,the production cross sections of the cold fusion system 76-82Se+209Bi and the hot fusion systems 55Mn+238U,51V-+244Pu,59 Co+232 Th,48 Ca+247-249 Bk and 45 Sc+246-248 Cm are calculated.The isotopic dependence of the largest production cross sections is analyzed briefly,and the optimal projectile-target combination and excitation energy of the ln-4n evaporation channels are proposed.It is shown that the hot fusion systems 48Ca+247 249Bk in the3n evaporation channels and 45Sc+248Cm in the 2n-4n channels are optimal for synthesizing the superheavy element 117.
Photoionization Modeling of the Low Luminosity Seyfert 1 Nucleus in NGC 3516
Devereux, Nick
2015-01-01
Spectroscopic observations of the low luminosity Seyfert 1 nucleus in NGC 3516 obtained with the Hubble Space Telescope show that the visible spectrum is dominated by the Balmer emission lines of Hydrogen (H) and a continuum luminosity that rises into the UV. The anomalous H${\\alpha}$/H${\\beta}$ emission line ratio, the Balmer emission line luminosity and the distinctive shape observed for the H${\\alpha}$ emission line profile serve as important constraints in any photoionization model aimed at explaining the visible emission line spectrum of NGC 3516. Photoionization modeling using Cloudy demonstrates that the central UV-X-ray source is able to completely ionize the H gas in between the Balmer and dust reverberation radii if the electron density is ${\\le}$ 3 ${\\times}$ 10${^7}$ cm${^{-3}}$ throughout. Thus, according to this model the region responsible for producing the visible H lines is a dust free shell of ionized H gas. Interestingly, the model predicts a rapid rise in the electron temperature as the ce...
Black-Scholes模型的参数估计%The Estimation of Parameters in Black-Scholes Model
Institute of Scientific and Technical Information of China (English)
肖庆宪; 张建海
2001-01-01
本文研究了Black-Scholes模型的参数估计问题，讨论了估计量的性质。%This paper discusses the estimation of parameters inBlack-Scholes model. The properties of the estimators are also discussed.
Makiya, Ryu; Enoki, Motohiro; Ishiyama, Tomoaki; Kobayashi, Masakazu A. R.; Nagashima, Masahiro; Okamoto, Takashi; Okoshi, Katsuya; Oogi, Taira; Shirakata, Hikari
2016-04-01
We present a new cosmological galaxy formation model, ν2GC, as an updated version of our previous model νGC. We adopt the so-called "semi-analytic" approach, in which the formation history of dark matter halos is computed by N-body simulations, while the baryon physics such as gas cooling, star formation, and supernova feedback are simply modeled by phenomenological equations. Major updates of the model are as follows: (1) the merger trees of dark matter halos are constructed in state-of-the-art N-body simulations, (2) we introduce the formation and evolution process of supermassive black holes and the suppression of gas cooling due to active galactic nucleus (AGN) activity, (3) we include heating of the intergalactic gas by the cosmic UV background, and (4) we tune some free parameters related to the astrophysical processes using a Markov chain Monte Carlo method. Our N-body simulations of dark matter halos have unprecedented box size and mass resolution (the largest simulation contains 550 billion particles in a 1.12 Gpc h-1 box), enabling the study of much smaller and rarer objects. The model was tuned to fit the luminosity functions of local galaxies and mass function of neutral hydrogen. Local observations, such as the Tully-Fisher relation, the size-magnitude relation of spiral galaxies, and the scaling relation between the bulge mass and black hole mass were well reproduced by the model. Moreover, the model also reproduced well the cosmic star formation history and redshift evolution of rest-frame K-band luminosity functions. The numerical catalog of the simulated galaxies and AGNs is publicly available on the web.
The smallest matrix black hole model in the classical limit
Berenstein, David
2016-01-01
We study the smallest non-trivial matrix model that can be considered to be a (toy) model of a black hole. The model consists of a pair of $2\\times 2$ traceless hermitian matrices with a commutator squared potential and an $SU(2)$ gauge symmetry, plus an $SO(2)$ rotation symmetry. We show that using the symmetries of the system, all but two of the variables can be separated. The two variables that remain display chaos and a transition from chaos to integrability when a parameter related to an $SO(2)$ angular momentum is tuned to a critical value. We compute the Lyapunov exponents near this transition and study the critical exponent of the Lyapunov exponents near the critical point. We compare this transition to extremal rotating black holes.
Generalized boson model and α-cluster states of 44Ti atomic nucleus
International Nuclear Information System (INIS)
At present some rotational bands for the 44Ti atomic nucleus with a sequence of spins and parities are discovered. For an analysis of these bands the generalized boson model U(6) direct X U(4) including the collective (quadrupole) degree of freedom and cluster (dipole) variable as well as an inter-relation of quadrupole and dipole degrees of freedom is used. Different collective bands of U(6) direct X SU(3) model reduction are considered as well. Parameter of SU(3) symmetrical Hamiltonian are equal to k=0.0016 MeV. (3/4k-k')=0.085 MeV. The U(4)contains U(3)-symmetry, caused by dipole clusterization of nucleons, describes bands of α-cluster states kπ=04+,02-, with theoretical parameters E0=-11 MeV, εp=0.1 MeV, β=0.15 MeV. An interaction of the cluster (dipole) degree with he quadrupole one allows to explain the band of parity, kπ=01-, beginning with E=6.22 MeV by values of parameters of kp=0, γ=6.2 MeV
Photoionization Modeling of the Low-luminosity Seyfert 1 Nucleus in NGC 3516
Devereux, Nick
2016-05-01
Spectroscopic observations of the low-luminosity Seyfert 1 nucleus in NGC 3516 obtained with the Hubble Space Telescope show that the visible spectrum is dominated by Balmer emission lines of hydrogen (H) and a continuum luminosity that rises into the UV. The anomalous {{H}}α /Hβ emission line ratio, the Balmer emission line luminosity, and the distinctive shape observed for the {{H}}α emission line profile serve as important constraints for any photoionization model aimed at explaining the visible emission line spectrum of NGC 3516. Photoionization modeling using Cloudy demonstrates that the central UV-X-ray source is able to completely ionize the H gas in between the Balmer and dust reverberation radii if the electron density is ≤slant 3 × {10}7 cm{}-3 throughout. Thus, according to this model the region responsible for producing the visible H lines is a dust-free shell of ionized H gas. Interestingly, the model predicts a rapid rise in the electron temperature as the central UV-X-ray source is approached, mirrored by an equally precipitous decrease in the Balmer line emissivity that coincides with the Balmer reverberation radius, providing a natural explanation for the finite width observed for H Balmer lines. Collectively, the merit of the model is that it explains the relative intensities of the three brightest Balmer lines and the shape of the {{H}}α emission line profile. However, questions remain concerning the unusually weak forbidden lines that cannot be addressed using Cloudy due to limitations with the code.
Towards Construction of a Unified Model for the Neutrino-Nucleus Reactions
Nakamura, S X; Hayato, Y; Hirai, M; Horiuchi, W; Kumano, S; Murata, T; Saito, K; Sakura, M; Sato, T; Suzuki, Y
2016-01-01
A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the react...
A multi-compartment model for interneurons in the dorsal lateral geniculate nucleus.
Directory of Open Access Journals (Sweden)
Geir Halnes
2011-09-01
Full Text Available GABAergic interneurons (INs in the dorsal lateral geniculate nucleus (dLGN shape the information flow from retina to cortex, presumably by controlling the number of visually evoked spikes in geniculate thalamocortical (TC neurons, and refining their receptive field. The INs exhibit a rich variety of firing patterns: Depolarizing current injections to the soma may induce tonic firing, periodic bursting or an initial burst followed by tonic spiking, sometimes with prominent spike-time adaptation. When released from hyperpolarization, some INs elicit rebound bursts, while others return more passively to the resting potential. A full mechanistic understanding that explains the function of the dLGN on the basis of neuronal morphology, physiology and circuitry is currently lacking. One way to approach such an understanding is by developing a detailed mathematical model of the involved cells and their interactions. Limitations of the previous models for the INs of the dLGN region prevent an accurate representation of the conceptual framework needed to understand the computational properties of this region. We here present a detailed compartmental model of INs using, for the first time, a morphological reconstruction and a set of active dendritic conductances constrained by experimental somatic recordings from INs under several different current-clamp conditions. The model makes a number of experimentally testable predictions about the role of specific mechanisms for the firing properties observed in these neurons. In addition to accounting for the significant features of all experimental traces, it quantitatively reproduces the experimental recordings of the action-potential- firing frequency as a function of injected current. We show how and why relative differences in conductance values, rather than differences in ion channel composition, could account for the distinct differences between the responses observed in two different neurons, suggesting
Black Hole Entropy Calculation in a Modified Thin Film Model
Indian Academy of Sciences (India)
Jingyi Zhang
2011-03-01
The thin film model is modified to calculate the black hole entropy. The difference from the original method is that the Parikh–Wilczek tunnelling framework is introduced and the self-gravitation of the emission particles is taken into account. In terms of our improvement, if the entropy is still proportional to the area, then the emission energy of the particles will satisfy = /360.
Numerical models of rotating accretion flows around black holes
Igumenshchev, I V
1999-01-01
Numerical, two-dimensional, time-dependent hydrodynamical models of geometrically thick accretion discs around black holes are presented. Accretion flows with non-effective radiation cooling (ADAFs) can be both convectively stable or unstable depending on the value of the viscosity parameter \\alpha. The high viscosity flows (\\alpha~1) are stable and have a strong equatorial inflow and bipolar outflows. The low viscosity flows (\\alpha<0.1) are convectively unstable and this induces quasi-periodic variability.
Persistent neuronal Ube3a expression in the suprachiasmatic nucleus of Angelman syndrome model mice.
Jones, Kelly A; Han, Ji Eun; DeBruyne, Jason P; Philpot, Benjamin D
2016-01-01
Mutations or deletions of the maternal allele of the UBE3A gene cause Angelman syndrome (AS), a severe neurodevelopmental disorder. The paternal UBE3A/Ube3a allele becomes epigenetically silenced in most neurons during postnatal development in humans and mice; hence, loss of the maternal allele largely eliminates neuronal expression of UBE3A protein. However, recent studies suggest that paternal Ube3a may escape silencing in certain neuron populations, allowing for persistent expression of paternal UBE3A protein. Here we extend evidence in AS model mice (Ube3a(m-/p+)) of paternal UBE3A expression within the suprachiasmatic nucleus (SCN), the master circadian pacemaker. Paternal UBE3A-positive cells in the SCN show partial colocalization with the neuropeptide arginine vasopressin (AVP) and clock proteins (PER2 and BMAL1), supporting that paternal UBE3A expression in the SCN is often of neuronal origin. Paternal UBE3A also partially colocalizes with a marker of neural progenitors, SOX2, implying that relaxed or incomplete imprinting of paternal Ube3a reflects an overall immature molecular phenotype. Our findings highlight the complexity of Ube3a imprinting in the brain and illuminate a subpopulation of SCN neurons as a focal point for future studies aimed at understanding the mechanisms of Ube3a imprinting. PMID:27306933
The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus 52Fe
Institute of Scientific and Technical Information of China (English)
LI YanSong; LONG GuiLu
2009-01-01
The relativistic consistent angular-momentum projected shell model (RECAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus 52Fe.The model calculations show a reasonably good agreement with the data.The backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.
The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus 52Fe
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus 52Fe.The model calculations show a reasonably good agreement with the data.The backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.
Nakamura, S X; Hirai, M; Kamano, H; Kumano, S; Sakuda, M; Saito, K; Sato, T
2013-01-01
Next generation neutrino oscillation experiments will need a quantitative understanding of neutrino-nucleus interaction far better than ever. Kinematics covered by the relevant neutrino-nucleus interaction spans wide region, from the quasi-elastic, through the resonance region, to the deeply inelastic scattering region. The neutrino-nucleus interaction in each region has quite different characteristics. Obviously, it is essential to combine different expertise to construct a unified model that covers all the kinematical region of the neutrino-nucleus interaction. Recently, several experimentalists and theorists got together to form a collaboration to tackle this problem. In this contribution, we report the collaboration's recent activity and a goal in near future.
A Model For The Absorption Of Thermal Radiation By Gold-Black
Quinlan, Brendan Robert
2015-01-01
The work presented here addresses an important topic in thermal radiation detection when gold-black is used as an absorber. Sought is a model to simulate the absorption of thermal radiation by gold-black. Fractal geometry is created to simulate the topology of gold-black. Then electrical circuits based on the topology are identified that capture the physics of the interaction between the gold-black material and incident electro-magnetic radiation. Parameters of the model are then adj...
Mitsikostas, D D; Sanchez del Rio, M
2001-03-01
In intracranial structures unmyelinated C- and Adelta-fibers of the trigeminal nerve transmit pain stimuli from meninges to the trigeminal nucleus caudalis (Sp5C). Peripheral nerve endings surround meningeal vessels (the so-called trigeminovascular system) and contain vasoactive neuropeptides (calcitonin gene-related peptide, substance P and neurokinin A). Activation of the trigeminovascular system promotes a meningeal sterile inflammatory response through the release of neuropeptides by peripheral endings. Orthodromic conduction along trigeminovascular fibers transmits information centrally with induction of immediate early c-fos gene within post-synaptic Sp5C neurons, as a marker of neuronal activity within central nociceptive pathways. In laboratory animals the system is activated by either electrical stimulation of the TG, chemical stimulation of the meninges, electrical or mechanical stimulation of the superior sagittal sinus or by induction of cortical spreading depression. All these techniques induce c-fos within Sp5C and are used as a rodent/feline model of vascular headache in humans. Up-to-date there is evidence that at least ten receptors (5-HT(1B), 5-HT(1D), 5-HT(lF), 5-HT(2B), NK-1, GABA(A), NMDA, AMPA, class III metabotropic glutamate receptors, and opioids mu receptors) modulate c-fos expression within Sp5C. These receptors represent potential targets for anti-migraine drugs as shown by triptans (5-HT(1B/1D/1F)) and ergot alkaloids (5-HT(1A1B/1D/1F)). This review discusses the importance of c-fos expression within Sp5C as a marker of cephalic nociception, the different cephalic pain models that induce c-fos within Sp5C, the receptors involved and their potential role as targets for anti-migraine drugs.
Accretion Disks Around Binary Black Holes: A Quasistationary Model
Liu, Yuk Tung
2010-01-01
Tidal torques acting on a gaseous accretion disk around a binary black hole can create a gap in the disk near the orbital radius. At late times, when the binary inspiral timescale due to gravitational wave emission becomes shorter than the viscous timescale in the disk, the binary decouples from the disk and eventually merges. Prior to decoupling the balance between tidal and viscous torques drives the disk to a quasistationary equilibrium state, perturbed slightly by small amplitude, spiral density waves emanating from the edges of the gap. We consider a black hole binary with a companion of smaller mass and construct a simple Newtonian model for a geometrically thin, Keplerian disk in the orbital plane of the binary. We solve the disk evolution equations in steady state to determine the quasistationary, (orbit-averaged) surface density profile prior to decoupling. We use our solution, which is analytic up to simple quadratures, to compute the electromagnetic flux and approximate radiation spectrum during th...
The Lieb-Liniger model at the critical point as toy model for Black Holes
Panchenko, Mischa
2015-01-01
In a previous series of papers it was proposed that black holes can be understood as Bose-Einstein condensates at the critical point of a quantum phase transition. Therefore other bosonic systems with quantum criticalities, such as the Lieb-Liniger model with attractive interactions, could possibly be used as toy models for black holes. Even such simple models are hard to analyse, as mean field theory usually breaks down at the critical point. Very few analytic results are known. In this paper we present a method of studying such systems at quantum critical points analytically. We will be able to find explicit expressions for the low energy spectrum of the Lieb-Liniger model and thereby to confirm the expected black hole like properties of such systems. This opens up an exciting possibility of constructing and studying black hole like systems in the laboratory.
Time series modelling and forecasting of Sarawak black pepper price
Liew, Venus Khim-Sen; Shitan, Mahendran; Hussain, Huzaimi
2000-01-01
Pepper is an important agriculture commodity especially for the state of Sarawak. It is important to forecast its price, as this could help the policy makers in coming up with production and marketing plan to improve the Sarawak’s economy as well as the farmers’welfare. In this paper, we take up time series modelling and forecasting of the Sarawak black pepper price. Our empirical results show that Autoregressive Moving Average (ARMA) time series models fit the price series well and they have...
The Nuclear $\\sigma$ Term in the Skyrme Model Pion-Nucleus Interaction
Gammal, A
1998-01-01
The nuclear sigma term is calculated including the nuclear matrix element of the derivative of the NN interaction with respect to the quark mass, $m_q\\frac{\\partial V_{NN}}{\\partial m_q}$. The NN potential is evaluated in the skyrmion-skyrmion picture within the quantized product ansatz. The contribution of the NN potential to the nuclear sigma term provides repulsion to the pion-nucleus interaction. The strength of the s-wave pion-nucleus optical potential is estimated including such contribution. The results are consistent with the analysis of the experimental data.
Juárez, Claudia; Morgado, Elvira; Waliszewski, Stefan M.; Martínez, Armando J.; Meza, Enrique; Caba, Mario
2012-01-01
Rabbit pups represent a natural model of food anticipatory activity (FAA). FAA is the behavioral output of a putative food entrainable oscillator (FEO). It had been suggested that the FEO is comprised of a distributed system of clocks that work in concert in response to gastrointestinal input by food. Scheduled food intake synchronizes several nuclei in the brain, and the hypothalamus has received particular attention. On the contrary, brainstem nuclei, despite being among the brain structures to first receive food cues, have been scarcely studied. Here we analyzed by immunohistochemistry possible oscillation of FOS and PER1 proteins through a complete 24 h cycle in the dorsal vagal complex (DVC) and parabrachial nucleus (PBN) of seven to eight day old rabbit pups scheduled to nurse during the night (02:00) or day (10:00) and also in fasted subjects to explore the possible persistence of oscillations. We found a clear induction of FOS that peaks 1.5 h after nursing in all nuclei studied. PER1 was only synchronized in the PBN, reaching highest values 12 h after nursing. Only PER1 oscillations persisted in fasted subjects. We conclude that the DVC nuclei are probably more related to the transmission of food cues to other brain regions but that the PBN participates in the integration of information essential for FAA. Our results support previous findings suggesting that the DVC nuclei, but not PBN, are not essential for FAA. We suggest that PBN is a key component of the proposed distributed system of clocks involved in FAA. PMID:22471601
The Dimensions of Subjective Well-Being among Black Americans: A Structural Model Analysis.
Tran, Thanh V.; And Others
1994-01-01
Analysis of data from 668 black adult respondents to the 1980 National Survey of Black Americans suggests that subjective well-being among black Americans is multidimensional. A three-factor model of subjective well-being encompassing strain (depressive symptoms), life satisfaction, and self-esteem was empirically supported and consistently…
Black Hole Atom as a Dark Matter Particle Candidate
Directory of Open Access Journals (Sweden)
V. I. Dokuchaev
2014-01-01
Full Text Available We propose the new dark matter particle candidate—the “black hole atom,” which is an atom with the charged black hole as an atomic nucleus and electrons in the bound internal quantum states. As a simplified model we consider the the central Reissner-Nordström black hole with the electric charge neutralized by the internal electrons in bound quantum states. For the external observers these objects would look like the electrically neutral Schwarzschild black holes. We suppose the prolific production of black hole atoms under specific conditions in the early universe.
Black Hole Atom as a Dark Matter Particle Candidate
International Nuclear Information System (INIS)
We propose the new dark matter particle candidate—the “black hole atom,” which is an atom with the charged black hole as an atomic nucleus and electrons in the bound internal quantum states. As a simplified model we consider the the central Reissner-Nordström black hole with the electric charge neutralized by the internal electrons in bound quantum states. For the external observers these objects would look like the electrically neutral Schwarzschild black holes. We suppose the prolific production of black hole atoms under specific conditions in the early universe
Muscarinic receptor-mediated calcium changes in a rat model of facial nerve nucleus injury
Institute of Scientific and Technical Information of China (English)
Dawei Sun; Huamin Liu; Fugao Zhu; Yanqing Wang; Junfeng Wen; Rui Zhou; Yanjun Wang; Banghua Liu
2010-01-01
The muscarinic receptor modulates intracellular free calcium ion levels in the facial nerve nucleus via different channels.In the present study,muscarinic receptor-mediated free calcium ions levels were detected by confocal laser microscopy in the facial nerve nucleus following facial nerve injury in rats.There was no significant difference in muscarinic receptor expression at the affected facial nerve nucleus compared with expression prior to injury,but muscarinic receptor-mediated free calcium ion levels increased in the affected side following facial nerve injury(P < 0.01).At day 30after facial nerve injury,50 μmol/L muscarinic-mediated free calcium ion levels were significantly inhibited at the affected facial nerve nucleus in calcium-free artificial cerebrospinal fluid,and the change range was 82% of artificial cerebrospinal fluid(P < 0.05).These results suggest that increased free calcium ion concentrations are achieved by intracellular calcium ion release,and that the transmembrane flow of calcium ions is also involved in this process.
On the lamppost model of accreting black holes
Niedzwiecki, Andrzej; Szanecki, Michal
2016-01-01
We study the lamppost model, in which the X-ray source in accreting black-hole systems is located on the rotation axis close to the horizon. We point out a number of inconsistencies in the widely used lamppost model relxilllp, e.g., the neglect of the redshift of the photons emitted by the lamppost and directly observed. They appear to invalidate those model fitting results for which the source distances from the horizon are within several gravitational radii. Furthermore, if those results were correct, most of the photons produced in the lamppost would be trapped by the black hole, and the luminosity generated in the source as measured at infinity would be much larger than that observed. This appears to be in conflict with the observed smooth state transitions between the hard and soft states of X-ray binaries. The required increase of the accretion rate and the associated efficiency reduction present also a problem for AGNs. Then, those models imply the luminosity measured in the local frame to be much high...
Model for nonsingular black hole collapse and evaporation
International Nuclear Information System (INIS)
We study the formation of a black hole and its subsequent evaporation in a model employing a minisuperspace approach to loop quantum gravity. In previous work the static solution was obtained and shown to be singularity-free. Here, we examine the more realistic dynamical case by generalizing the static case with the help of the Vaidya metric. We track the formation and evolution of trapped surfaces during collapse and evaporation and examine the buildup of quantum gravitationally caused stress energy preventing the formation of a singularity.
Black Hole Entropy Associated with Supersymmetric Sigma Model
Abdalla, Maria Christina B; Guimarães, M E X
2003-01-01
By means of an identity that equates elliptic genus partition function of a supersymmetric sigma model on the $N$-fold symmetric product $S^N X$ of $X$ ($S^N X=X^N/S_N$, $S_N$ is the symmetric group of $N$ elements) to the partition function of a second quantized string theory, we derive the asymptotic expansion of the partition function as well as the asymptotic for the degeneracy of spectrum in string theory. The asymptotic expansion for the state counting reproduces the logarithmic correction to the black hole entropy.
Large scale experiments and modeling of black liquor gasification
Energy Technology Data Exchange (ETDEWEB)
Carlsson, Per
2011-07-01
Biomass gasification could provide a basis for increased electricity and engine fuel production from a renewable source in the pulp and paper industry. This work focuses on the largest byproduct available at the pulp mills, black liquor. Black liquor is a mixture of spent cooking chemicals, dissolved lignin, dissolved carbohydrates and a small portion of inorganic compounds found in the wood. The conventional technology to recover the cooking chemicals and the chemical energy as heat is combustion in large boilers. Here, gasification could be an alternative, replacing or complementing the boilers. The gasification technology produces a combustible gas that can be cleaned to produce electricity in a gas turbine/engine or, be synthesized into valuable chemicals or liquid engine fuels. The technology has been demonstrated in development scale since 2005 and appears to be promising. Still, commercial plants have not yet been built. This thesis focuses on the understanding of the oxygen blown, pressurized, entrained flow, black liquor gasification technology. The main goals have been to increase the understanding about the dominating mechanisms in black liquor gasification and to develop an engineering tool that can be used to design and optimize, pressurized, entrained flow, black liquor gasifiers. To accomplish these goals gas samples were extracted from the gasification reactor using a gas sampling probe that was developed within this work. Gas samples were also collected downstream the quench located underneath the reactor and the results were compared. Finally, an existing numerical model was developed so it can predict the behavior of the black liquor gasifier within reasonable accuracy. Even though the actual mechanisms in the reactor and quench are very complex it appears that they can be described with relatively simple global mechanisms. The main gas components are dictated by the water gas shift reaction. At the outlet of the reactor the gas composition is
International Nuclear Information System (INIS)
The energy spectrum of the 12C nucleus with (Jπ,T)=(0+,0) and (2+,0) is investigated within the framework of the multicluster dynamical model by using a deep α α-potential with forbidden states in the S and D waves. A very high sensitivity of the compact ground and first excited 2+1 state energy levels to the description of the two-body forbidden states wavefunctions has been established. It is also shown that the chosen method of orthogonalizing pseudopotentials yields convergent results for the energies of the excited (0+2,0) and (0+3,0) states of the 12C nucleus with a well developed cluster-like structure. (author)
A dynamical evolution model on the black-hole horizon
Energy Technology Data Exchange (ETDEWEB)
Zhu Jianyang [Department of Physics, Beijing Normal University, Beijing 100875 (China); CCAST (World Laboratory), Box 8730, Beijing 100080 (China)
2005-07-07
This paper demonstrates a dynamical evolution model of the black-hole (BH) horizon. The result indicates that a kinetic area-cell model of the BH horizon can model the evolution of the BH due to the Hawking radiation, and this area-cell system can be considered as an interacting geometrical particle system. Thus, the evolution turns into a problem of statistical physics. In the present work, this problem is treated in the framework of non-equilibrium statistics. It is proposed that each area cell possesses energy like a microscopic black hole and has gravitational interaction with the other area cells. We consider both a non-interaction ideal system and a system with small nearest-neighbour interactions, and obtain an analytic expression of the expected value of the horizon area of a dynamical BH. We find that, after a long enough evolution, a dynamical BH with the Hawking radiation can be in equilibrium with a finite-temperature radiation field. However, we also find that the system has a critical point, and when the temperature of the radiation field surrounding the BH approaches the critical temperature of the BH, a critical slowing-down phenomenon occurs.
Dark Matter Primordial Black Holes and Inflation Models
Drees, Manuel
2012-01-01
A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of long--lived Primordial Black Holes (PBHs) as candidate for dark matter. To that end we calculate the spectral index of the power spectrum of primordial perturbations as well as its first and second derivatives. PBH formation is possible only if the spectral index $n_S(k_0)$ increases significantly at small scales. Since current data indicate that the first derivative $\\alpha_S$ of the spectral index is negative at the pivot scale, PBH formation is only possible in the presence of a sizable and positive second derivative ("running of the running") $\\beta_S$. Among the three small-field and five large-field models we analyze, only the "running-mass" model allows PBH formation, for a narrow range of parameters.
Is Black-Scholes Model An Appropriate Option Pricing Tool in Chinese Stock Market?
Mao, Qing
2007-01-01
In order to further develop the derivative markets, the Chinese government has decided to launch stock options as soon as possible. The Black-Scholes formula has been the most commonly used option pricing model today. But is the Black-Scholes model an appropriate tool for pricing of Chinese stock option? If the Black-Sholes model is perfect, implied volatilities should be exactly the same for options on the same underlying asset with different strike prices. This project, however, discove...
Lithium ameliorates nucleus accumbens phase signaling dysfunction in a genetic mouse model of mania
Dzirasa, Kafui; Coque, Laurent; Sidor, Michelle M.; Kumar, Sunil; Dancy, Elizabeth A.; Takahashi, Joseph S.; McClung, Colleen A.; Nicolelis, Miguel A.L.
2010-01-01
Polymorphisms in circadian genes such as CLOCK convey risk for bipolar disorder. While studies have begun to elucidate the molecular mechanism whereby disruption of Clock alters cellular function within mesolimbic brain regions, little remains known about how these changes alter gross neural circuit function and generate mania-like behaviors in Clock-Δ19 mice. Here we show that the phasic entrainment of nucleus accumbens (NAC) low-gamma (30–55Hz) oscillations to delta (1–4Hz) oscillations is ...
Nicotine alpha 4 beta 2 receptor-mediated free calcium in an animal model of facial nucleus injury
Institute of Scientific and Technical Information of China (English)
Dawei Sun; Wenhai Sun; Yanqing Wang; Fugao Zhu; Rui Zhou; Yanjun Wang; Banghua Liu; Xiuming Wan; Huamin Liu
2010-01-01
Previous studies have demonstrated that the cholinergic system,via nicotinic receptors,regulates intracellular free calcium levels in the facial nucleus under normal physiological conditions.However,the regulation of nicotinic receptors on free calcium levels following facial nerve injury remains unclear.In the present study,an animal model of facial nerve injury was established,and changes in nicotinic receptor expression following facial nerve injury in rats were detected using reverse transcription polymerase chain reaction.Nicotinic receptor-mediated changes of free calcium levels following facial nucleus injury were determined by laser confocal microscopy.Results showed no significant difference in nicotinic receptor expression between the normal group and the affected facial nerve nucleus.The nicotinic receptor α4β2 subtype increased free calcium levels following facial nerve injury by promoting calcium transmembrane influx,and L-type voltage-gated calcium channel-mediated influx of calcium ions played an important role in promoting calcium transmembrane influx.The nicotinic receptor-mediated increase of free calcium levels following facial nerve injury provides an important mechanism for the repair of facial nerve injury.
Caranicolas, Nicolaos D
2012-01-01
We investigate the transition from regular to chaotic motion in a composite galaxy model with a disk-halo, a massive dense nucleus and a dark halo component. We obtain relationships connecting the critical value of the mass of the nucleus or the critical value of the angular momentum, with the mass of the dark halo, where the transition from regular motion to chaos occurs. We also present 3D diagrams connecting the mass of nucleus the energy and the percentage of stars that can show chaotic motion. The fraction of the chaotic orbits observed in the phase plane, as a function of the mass of the dark halo is also computed. We use a semi-numerical method, that is a combination of theoretical and numerical procedure. The theoretical results obtained using the version 8.0 of the Mathematica package, while all the numerical calculations were made using a Bulirsch-Stoer FORTRAN routine in double precision. The results can be obtained in semi-numerical or numerical form and give good description for the connection of...
The nature of orbits in a prolate elliptical galaxy model with a bulge and a dense nucleus
Institute of Scientific and Technical Information of China (English)
Nicolaos D. Caranicolas; Euaggelos E. Zotos
2011-01-01
We study the transition from regular to chaotic motion in a prolate elliptical galaxy dynamical model with a bulge and a dense nucleus.Our numerical investigation shows that stars with angular momentum Lz less than or equal to a critical value Lzc,moving near the galactic plane,are scattered to higher z,when reaching the central region of the galaxy,thus displaying chaotic motion.An inverse square law relationship was found to exist between the radius of the bulge and the critical value Lzc of the angular momentum.On the other hand,a linear relationship exists between the mass of the nucleus and Lzc.The numerically obtained results are explained using theoretical arguments.Our study shows that there are connections between regular or chaotic motion and the physical parameters of the system,such as the star's angular momentum and mass,the scale length of the nucleus and the radius of the bulge.The results are compared with the outcomes of previous work.
Nonspinning black hole-neutron star mergers: a model for the amplitude of gravitational waveforms
Pannarale, Francesco; Kyutoku, Koutarou; Shibata, Masaru
2013-01-01
Black hole-neutron star binary mergers display a much richer phenomenology than black hole-black hole mergers, even in the relatively simple case - considered in this paper - in which both the black hole and the neutron star are nonspinning. When the neutron star is tidally disrupted, the gravitational wave emission is radically different from the black hole-black hole case and it can be broadly classified in two groups, depending on the spatial extent of the disrupted material. We present a phenomenological model for the gravitational waveform amplitude in the frequency domain that encompasses the three possible outcomes of the merger: no tidal disruption, "mild", and "strong" tidal disruption. The model is calibrated to general relativistic numerical simulations using piecewise polytropic neutron star equations of state. It should prove useful to extract information on the nuclear equation of state from future gravitational-wave observations, and also to obtain more accurate estimates of black hole-neutron ...
Institute of Scientific and Technical Information of China (English)
马红武; 赵学明; 唐寅杰
1999-01-01
The xanthan fermentation data in the stationary phase was analyzed using the black box and the metabolic network models. The data consistency ls checked through the elemental balance in the black box model. In the metabolic network model, the metabolic flux distribution in the cell is calculated using the metabolic flux analysis method, then the maintenance coefficients is calculated.
Black Hole Demography: From scaling relations to models
Shankar, Francesco
2013-01-01
In this contributed paper I review our current knowledge of the local Black Hole (BH) scaling relations, and their impact on the determination of the local BH mass function. I particularly emphasize the remaining systematic uncertainties impinging upon a secure determination of the BH mass function and how progress can be made. I then review and discuss the evidence for a different time evolution for separate BH-galaxy scaling relations, and how these independent empirical evidences can be reconciled with the overall evolution of the structural properties of the host galaxies. I conclude discussing BH demography in the context of semi-empirical continuity accretion models, as well as more complex evolutionary models, emphasizing the general constraints we can set on them.
Tran, Thanh Thuy; Nguyen, Phuong H.; Derreumaux, Philippe
2016-05-01
Coarse-grained protein lattice models approximate atomistic details and keep the essential interactions. They are, therefore, suitable for capturing generic features of protein folding and amyloid formation at low computational cost. As our aim is to study the critical nucleus sizes of two experimentally well-characterized peptide fragments Aβ16-22 and Aβ37-42 of the full length Aβ1-42 Alzheimer's peptide, it is important that simulations with the lattice model reproduce all-atom simulations. In this study, we present a comprehensive force field parameterization based on the OPEP (Optimized Potential for Efficient protein structure Prediction) force field for an on-lattice protein model, which incorporates explicitly the formation of hydrogen bonds and directions of side-chains. Our bottom-up approach starts with the determination of the best lattice force parameters for the Aβ16-22 dimer by fitting its equilibrium parallel and anti-parallel β-sheet populations to all-atom simulation results. Surprisingly, the calibrated force field is transferable to the trimer of Aβ16-22 and the dimer and trimer of Aβ37-42. Encouraged by this finding, we characterized the free energy landscapes of the two decamers. The dominant structure of the Aβ16-22 decamer matches the microcrystal structure. Pushing the simulations for aggregates between 4-mer and 12-mer suggests a nucleus size for fibril formation of 10 chains. In contrast, the Aβ37-42 decamer is largely disordered with mixed by parallel and antiparallel chains, suggesting that the nucleus size is >10 peptides. Our refined force field coupled to this on-lattice model should provide useful insights into the critical nucleation number associated with neurodegenerative diseases.
Wetting and Non-Wetting Models of Black Carbon Activation
Henson, B. F.; Laura, S.
2006-12-01
We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a
Evaluation of black carbon estimations in global aerosol models
Directory of Open Access Journals (Sweden)
Y. Zhao
2009-11-01
Full Text Available We evaluate black carbon (BC model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD retrievals from AERONET and Ozone Monitoring Instrument (OMI and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.7 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 8 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC ratio is 0.4 and models underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model
Evaluation of black carbon estimations in global aerosol models
Directory of Open Access Journals (Sweden)
D. Koch
2009-07-01
Full Text Available We evaluate black carbon (BC model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD from AERONET and Ozone Monitoring Instrument (OMI retrievals and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.6 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50 N, the average model is a factor of 10 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC is 0.6 and underestimates the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a
Evaluation of Black Carbon Estimations in Global Aerosol Models
Energy Technology Data Exchange (ETDEWEB)
Koch, D.; Schulz, M.; Kinne, Stefan; McNaughton, C. S.; Spackman, J. R.; Balkanski, Y.; Bauer, S.; Berntsen, T.; Bond, Tami C.; Boucher, Olivier; Chin, M.; Clarke, A. D.; De Luca, N.; Dentener, F.; Diehl, T.; Dubovik, O.; Easter, Richard C.; Fahey, D. W.; Feichter, J.; Fillmore, D.; Freitag, S.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Klimont, Z.; Kondo, Yutaka; Krol, M.; Liu, Xiaohong; Miller, R.; Montanaro, V.; Moteki, N.; Myhre, G.; Penner, J.; Perlwitz, Ja; Pitari, G.; Reddy, S.; Sahu, L.; Sakamoto, H.; Schuster, G.; Schwarz, J. P.; Seland, O.; Stier, P.; Takegawa, Nobuyuki; Takemura, T.; Textor, C.; van Aardenne, John; Zhao, Y.
2009-11-27
We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD) from AERONET and OMI retrievals and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column) AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.6 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 10 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC is 0.6 and underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a smaller change in model predictions than the
Review on the structural approach of the Black-Scholes model
Saad, Shakila; Jaffar, Maheran Mohd
2015-05-01
Black-Scholes model developed in 1973 has become one of the important concepts in modern financial theory. This model is regarded as one of the best ways in determining fair prices of the options. Many studies have been done to improve the performance of the Black-Scholes model since this model is built with few limitations. Thus, the objective of this review paper is to discuss on the Black-Scholes model. The aim of this review paper is to present the derivation of Black-Scholes, Merton and KMV-Merton models. Besides, it provides a literature review on the modifications done by the researchers on the Black-Scholes model.
Entrained Flow Black Liquor Gasification - Detailed Experiments and Mathematical Modelling
Energy Technology Data Exchange (ETDEWEB)
Carlsson, Per (Energy Technology Centre, Piteaa (Sweden)), e-mail: per.carlsson@etcpitea.se
2009-07-01
Black liquor, a by-product from the Kraft pulping process is a highly viscous fluid consisting of approximately 30% water, 30 % alkali salts and 40 % combustible material. The alkali salts originating from the pulp making process need to be recovered in order for the pulp mill to be economical and to satisfy environmental regulation. Currently, the recovery takes place in large boilers called Tomlinson recovery boilers. However, a more energy efficient way to recover the chemicals could be via gasification in a pressurized, entrained flow, high temperature gasifier. To demonstrate this technology a development plant (DP1) was built in 2005 by the technology vendor Chemrec. Since then, the plant has been running for more than 10,000 h and frequently been updated and optimized. As steps towards commercialization and scale-up different computational models of varying sophistication are used as design and optimization tools for the process. Still, the engineering tools can only provide sensible predictions if they are properly validated and verified. This thesis is concerned with validation of a comprehensive mathematical model based on Computational Fluid Dynamics (CFD) describing the gasification reactor and experimental investigations of the process characteristics in the DP1 gasifier. Paper A describes the system design and methodology for high temperature gas sampling during pressurized black liquor gasification. In this work a water-cooled gas sampling probe is installed in the hot part of the DP1 gasification reactor and several gas samples are withdrawn and analyzed. The experimentally obtained data in Paper A are then used as validation data for the CFD-model described in Paper B. In Paper C the obtained data from Paper A are thoroughly analyzed and the influence of reactor operation on producer gas composition is determined. In Paper D black liquor sprays from a gas assisted nozzle is experimentally investigated using high speed photography. Furthermore, the
Accuracy of Binary Black Hole Waveform Models for Advanced LIGO
Kumar, Prayush; Fong, Heather; Barkett, Kevin; Bhagwat, Swetha; Afshari, Nousha; Chu, Tony; Brown, Duncan; Lovelace, Geoffrey; Pfeiffer, Harald; Scheel, Mark; Szilagyi, Bela; Simulating Extreme Spacetimes (SXS) Team
2016-03-01
Coalescing binaries of compact objects, such as black holes and neutron stars, are the primary targets for gravitational-wave (GW) detection with Advanced LIGO. Accurate modeling of the emitted GWs is required to extract information about the binary source. The most accurate solution to the general relativistic two-body problem is available in numerical relativity (NR), which is however limited in application due to computational cost. Current searches use semi-analytic models that are based in post-Newtonian (PN) theory and calibrated to NR. In this talk, I will present comparisons between contemporary models and high-accuracy numerical simulations performed using the Spectral Einstein Code (SpEC), focusing at the questions: (i) How well do models capture binary's late-inspiral where they lack a-priori accurate information from PN or NR, and (ii) How accurately do they model binaries with parameters outside their range of calibration. These results guide the choice of templates for future GW searches, and motivate future modeling efforts.
Casado, J M
2015-01-01
Rhythms in electrical activity in the membrane of cells in the suprachiasmatic nucleus (SCN) are crucial for the function of the circadian timing system, which is characterized by the expression of the so-called clock genes. Intracellular Ca$^{2+}$ ions seem to connect, at least in part, the electrical activity of SCN neurons with the expression of clock genes. In this paper, we introduce a simple mathematical model describing the linking of membrane activity to the transcription of one gene by means of a feedback mechanism based on the dynamics of intracellular calcium ions.
Running-Mass Inflation Model and Primordial Black Holes
Drees, Manuel
2011-01-01
We revisit the question whether the running-mass inflation model allows the formation of Primordial Black Holes (PBHs) that are sufficiently long-lived to serve as candidates for Dark Matter. We incorporate recent cosmological data, including the WMAP 7-year results. Moreover, we include ``the running of the running'' of the spectral index of the power spectrum, as well as the renormalization group ``running of the running'' of the inflaton mass term. Our analysis indicates that formation of sufficiently heavy, and hence long-lived, PBHs still remains possible in this scenario. As a by-product, we show that the additional term in the inflaton potential still does not allow significant negative running of the spectral index.
Constraints on the α+nucleus optical-model potential via α-induced reaction studies on 108Cd
Directory of Open Access Journals (Sweden)
P. Scholz
2016-10-01
Full Text Available A big part in understanding the nucleosynthesis of heavy nuclei is a proper description of the effective interaction between an α-particle and a target nucleus. Information about the so-called α+nucleus optical-model potential is achieved by precise cross-section measurements at sub-Coulomb energies aiming to constrain the theoretical models for the nuclear physics input-parameters. The cross sections of the 108Cd(α,γ and 108Cd(α,n reaction have been measured for the first time close to the astrophysically relevant energy region via the in-beam method at the high-efficiency γ-ray spectrometer HORUS and via the activation technique at the Cologne Clover Counting Setup at the Institute for Nuclear Physics in Cologne, Germany. Comparisons between experimental results and theoretical predictions calculated in the scope of the Hauser–Feshbach statistical model confirm the need for a exponentially decreasing imaginary part of the potential. Moreover, it is shown that the results presented here together with already published data indicate that a systematic investigation of the real part of the potential could help to further improve the understanding of reactions involving α-particles.
Constraints on the α + nucleus optical-model potential via α-induced reaction studies on 108Cd
Scholz, P.; Heim, F.; Mayer, J.; Münker, C.; Netterdon, L.; Wombacher, F.; Zilges, A.
2016-10-01
A big part in understanding the nucleosynthesis of heavy nuclei is a proper description of the effective interaction between an α-particle and a target nucleus. Information about the so-called α +nucleus optical-model potential is achieved by precise cross-section measurements at sub-Coulomb energies aiming to constrain the theoretical models for the nuclear physics input-parameters. The cross sections of the 108Cd(α , γ) and 108Cd(α , n) reaction have been measured for the first time close to the astrophysically relevant energy region via the in-beam method at the high-efficiency γ-ray spectrometer HORUS and via the activation technique at the Cologne Clover Counting Setup at the Institute for Nuclear Physics in Cologne, Germany. Comparisons between experimental results and theoretical predictions calculated in the scope of the Hauser-Feshbach statistical model confirm the need for a exponentially decreasing imaginary part of the potential. Moreover, it is shown that the results presented here together with already published data indicate that a systematic investigation of the real part of the potential could help to further improve the understanding of reactions involving α-particles.
Ciliberti, Stefania Angela; Peneva, Elisaveta; Storto, Andrea; Rostislav, Kandilarov; Lecci, Rita; Yang, Chunxue; Coppini, Giovanni; Masina, Simona; Pinardi, Nadia
2016-04-01
This study describes a new model implementation for the Black Sea, which uses data assimilation, towards operational forecasting, based on NEMO (Nucleus for European Modelling of the Ocean, Madec et al., 2012). The Black Sea domain is resolved with 1/27°×1/36° horizontal resolution (~3 km) and 31 z-levels with partial steps based on the GEBCO bathymetry data (Grayek et al., 2010). The model is forced by momentum, water and heat fluxes interactively computed by bulk formulae using high resolution atmospheric forcing provided by the European Centre for Medium-Range Forecast (ECMWF). The initial condition is calculated from long-term climatological temperature and salinity 3D fields. Precipitation field over the basin has been computed from the climatological GPCP rainfall monthly data (Adler et al., 2003; Huffman et al., 2009), while the evaporation is derived from the latent heat flux. The climatological monthly mean runoff of the major rivers in the Black Sea is computed using the hydrological dataset provided by SESAME project (Ludvig et al., 2009). The exchange with Mediterranean Sea through the Bosporus Straits is represented by a surface boundary condition taking into account the barotropic transport calculated to balance the fresh water fluxes on monthly bases (Stanev and Beckers, 1999, Peneva et al., 2001). A multi-annual run 2011-2015 has been completed in order to describe the main characteristics of the Black Sea circulation dynamics and thermohaline structure and the numerical results have been validated using in-situ (ARGO) and satellite (SST, SLA) data. The Black Sea model represents also the core of the new Black Sea Forecasting System, implemented at CMCC operationally since January 2016, which produces at daily frequency 10-day forecasts, 3-days analyses and 1-day simulation. Once a week, the system is run 15-day in the past in analysis mode to compute the new optimal initial condition for the forecast cycle. The assimilation is performed by a
ON THE LAMPPOST MODEL OF ACCRETING BLACK HOLES
Energy Technology Data Exchange (ETDEWEB)
Niedźwiecki, Andrzej; Szanecki, Michał [Łódź University, Department of Physics, Pomorska 149/153, 90-236 Łódź (Poland); Zdziarski, Andrzej A. [Centrum Astronomiczne im. M. Kopernika, Bartycka 18, 00-716 Warszawa (Poland)
2016-04-10
We study the lamppost model, in which the X-ray source in accreting black hole (BH) systems is located on the rotation axis close to the horizon. We point out a number of inconsistencies in the widely used lamppost model relxilllp, e.g., neglecting the redshift of the photons emitted by the lamppost that are directly observed. They appear to invalidate those model fitting results for which the source distances from the horizon are within several gravitational radii. Furthermore, if those results were correct, most of the photons produced in the lamppost would be trapped by the BH, and the luminosity generated in the source as measured at infinity would be much larger than that observed. This appears to be in conflict with the observed smooth state transitions between the hard and soft states of X-ray binaries. The required increase of the accretion rate and the associated efficiency reduction also present a problem for active galactic nuclei. Then, those models imply the luminosity measured in the local frame is much higher than that produced in the source and measured at infinity, due to the additional effects of time dilation and redshift, and the electron temperature is significantly higher than that observed. We show that these conditions imply that the fitted sources would be out of the e{sup ±} pair equilibrium. On the other hand, the above issues pose relatively minor problems for sources at large distances from the BH, where relxilllp can still be used.
A model of radiating black hole in noncommutative geometry
Nicolini, Piero
2005-01-01
The phenomenology of a radiating Schwarzschild black hole is analyzed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: i) the existence of a minimal non-zero mass to which black hole can shrink; ii) a finite maximum temperature that the black hole can reach before cooli...
Modeling motion of a small black hole through a star or a planet
Turova, Victoria; Panin, Alexander
2012-10-01
In some scenarios of Big Bang the fluctuations of density in early universe result in the formation of various sized primordial black holes. The black holes of mass range 10^10 -10^22 kg are suitable candidates for a dark matter (or at least for a part of it). Such black holes could from time to time pass via Solar system or Sun or even Earth. What would a trajectory of a small black hole passing through Sun or through Earth look like? Would a black hole slow down and stuck consuming matter and causing cataclysmic collapse of Earth or Sun, or would it just pass? What other effects would take place? We model computationally a motion of a small black hole moving with various initial velocities (10- 1000 km/sec) through a planet-like and a star-like body of various density distributions. The results of this modeling are presented.
VBSM: VCC-Based Black Box Service Model with Enhanced Data Integrity
Directory of Open Access Journals (Sweden)
Won Min Kang
2014-10-01
Full Text Available Recently, intelligent transport systems have been applied to vehicle cloud environments. Such technology is especially useful for the systematic management of road traffic. Moreover, automobiles are increasingly equipped with a black box for accident prevention and preservation of evidence. Vehicle black boxes have become mandatory because black box images and voice data have served as forensic evidence in courts. However, the data from black boxes can be forged or modified by man-in-the-middle (MITM attacks and message hijacking. In this paper, we propose a vehicle cloud computing-based black box service model that can provide integrity for black box data through digital signatures in vehicle cloud computing (VCC environments. Our proposed model protects against MITM attacks and message hijacking using only a hash value and digital signature. Moreover, a mirroring technique (RAID 1 provides backup and recovery to protect the data from a traffic accident.
A model of radiating black hole in noncommutative geometry
Energy Technology Data Exchange (ETDEWEB)
Nicolini, Piero [Dipartimento di Matematica e Informatica, Universita di Trieste, Trieste (Italy); Institut Jozef Stefan, Ljubljana (Slovenia); Dipartimento di Matematica, Politecnico di Torino, Turin (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy)
2005-09-30
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
A model of radiating black hole in noncommutative geometry
International Nuclear Information System (INIS)
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
Effect of climate variables on cocoa black pod incidence in Sabah using ARIMAX model
Ling Sheng Chang, Albert; Ramba, Haya; Mohd. Jaaffar, Ahmad Kamil; Kim Phin, Chong; Chong Mun, Ho
2016-06-01
Cocoa black pod disease is one of the major diseases affecting the cocoa production in Malaysia and also around the world. Studies have shown that the climate variables have influenced the cocoa black pod disease incidence and it is important to quantify the black pod disease variation due to the effect of climate variables. Application of time series analysis especially auto-regressive moving average (ARIMA) model has been widely used in economics study and can be used to quantify the effect of climate variables on black pod incidence to forecast the right time to control the incidence. However, ARIMA model does not capture some turning points in cocoa black pod incidence. In order to improve forecasting performance, other explanatory variables such as climate variables should be included into ARIMA model as ARIMAX model. Therefore, this paper is to study the effect of climate variables on the cocoa black pod disease incidence using ARIMAX model. The findings of the study showed ARIMAX model using MA(1) and relative humidity at lag 7 days, RHt - 7 gave better R square value compared to ARIMA model using MA(1) which could be used to forecast the black pod incidence to assist the farmers determine timely application of fungicide spraying and culture practices to control the black pod incidence.
Lattice approximations for Black-Scholes type models in Option Pricing
Karlén, Anne; Nohrouzian, Hossein
2013-01-01
This thesis studies binomial and trinomial lattice approximations in Black-Scholes type option pricing models. Also, it covers the basics of these models, derivations of model parameters by several methods under different kinds of distributions. Furthermore, the convergence of the binomial model to normal distribution, Geometric Brownian Motion and Black-Scholes model is discussed. Finally, the connections and interrelations between discrete random variables under the Lattice approach and con...
Triaxial projected shell model study of transition probabilities for 134Pr nucleus
International Nuclear Information System (INIS)
The quest to establish stable triaxial shapes in nuclei is being pursued with keen interest during the last about half-a-century. In the initial phases for it, the structures of energy levels at relatively low angular momenta were considered. Generally, the deviations from axially symmetric shape are expected at high spins since the rotational effects are strong for high-j orbitals. The loss of axial symmetry affects a number of observables. For a nucleus having a stable triaxial shape, different moments of inertia are associated with each of the principal axes and the rotational motion is possible about all the three axes. Therefore, the rotational spectra are expected to be richer for stable triaxial nuclei as compared to that for axially symmetric deformed nuclei. There are several empirical observations indicating that axial symmetry is broken in transitional regions and therefore the nuclei in these regions have triaxial shapes
Unification models with reheating via primordial black holes
Hidalgo, J. C.; Urena-Lopez, L. Arturo; Liddle, Andrew R.
2011-01-01
We study the possibility of reheating the universe through the evaporation of primordial black holes created at the end of inflation. This is shown to allow for the unification of inflation and dark matter under the dynamics of a single scalar field. We determine the necessary conditions to recover the standard Big Bang by the time of nucleosynthesis after reheating through black holes.
Modeling Manhood: Reimagining Black Male Identities in School
Givens, Jarvis R.; Nasir, Na'ilah; ross, kihana; de Royston, Maxine McKinney
2016-01-01
This paper examines the process by which stereotypical mainstream representations of black males (as hard, as anti-school, and as disconnected from the domestic sphere) were reimagined in all-black, all-male manhood development classes for 9th graders in urban public high schools. Findings show that instructors debunked stereotypes and created new…
A Toy Model for Black Hole in Noncommutative Spaces
Demetrian, M.; Presnajder, P.
2006-01-01
We present a new point of view on the problem of the Schwarzschild black hole in the noncommutative spaces, proposed recently by F. Nasseri. We apply our treatment also to the case of the 2+1 dimensional Ba\\~ nados-Teitelboim-Zanelli black hole.
Institute of Scientific and Technical Information of China (English)
Xin Li; Shuande Li
2008-01-01
BACKGROUND: It has been demonstrated that the septal nucleus is involved in the pathogenesis of schizophrenia. Based on autopsies of schizophrenia patients, studies have shown a reduced number of septal nucleus neurons and gila. In addition, experimental rat models of schizophrenia have shown increased dopamine receptor D2 binding sites in the basal ganglia, septal nuclei, and substantia nigra. Previous studies have demonstrated that the septal nucleus modulates dopamine metabolic disorder and dopamine D2 receptor balance.OBJECTIVE: Dopamine D2 receptor expression in a rat model of schizophrenia, combined with antipsychotic drugs, was analyzed in the prefrontal lobe, striatum, and brainstem. In situ hybridization was used to observe the effects of stereotactic septal nucleus lesions on dopamine D2 receptor expression in the brains of methylamphetamine-treated rats. DESIGN, TIME AND SETTING: A randomized, controlled, animal experiment was performed in the Laboratory of General Institute of Psychosurgery, Third Hospital of Chinese PLA from November 2005 to June 2006. MATERIALS: A total of 120 healthy, adult Sprague Dawley rats, weighing approximately 200 g, were included. Methylamphetamine (Sigma, USA) and an in situ hybridization detection kit for dopamine D2 receptor (Boster, China) were also used for this study. METHODS: All rats were randomly allocated to the following 4 groups, with 30 rats in each group: normal control, simple administration, septal nucleus lesion, and sham-operated groups. In the normal control group, rats were not administered or lesioned. In the remaining 3 groups, rats were intraperitoneally administered 10 mg/kg methylamphetamine, once per day, for 15 successive days to establish a schizophrenia model. Following successful model establishment, rats from the septal nucleus lesion group were subjected to stereotactic septal nucleus lesions. The cranial bone was exposed in rats from the sham-operated group, and the septal nucleus was not
APPLYING BLACK-BOX TESTING TO MODEL TRANSFORMATIONS IN THE MODEL DRIVEN ARCHITECTURE CONTEXT
Directory of Open Access Journals (Sweden)
Luciane Telinski Wiedermann Agner
2014-01-01
Full Text Available Testing model transformations has played a leading role with the dissemination of MDA in software development processes. Software testing based on black-box testing, together with the “category partitioning” method, can be efficiently used in order to conduct the verification of model transformations. This study employs software testing techniques to an ATL model transformation in the MDA context and points out their benefits. The black-box testing method was adapted to the MT-PROAPES model transformation based on profiles and platform models. The platform models define the range of input models of the MT-PROAPES and are used for the creation of the test cases. The test cases were selected so as to meet certain requirements and increase the ability to detect errors in the model transformation. This approach makes the test process more agile and does not require any abstraction of behavioral properties of the transformations. The field of transformation testing and verification still faces significant challenges and requires a lot of research. Although having some limitations, black-box testing conforms to various situations, besides allowing its integration with other test strategies.
International Nuclear Information System (INIS)
A new dispersive coupled-channel optical model potential (OMP) for 238U nucleus is presented. The derived OMP couples almost all 238U excited levels below 1 MeV of excitation energy, including the ground state, octupole, beta, gamma, and non-axial bands. The coupled-channel potential is based on a vibrational-rotational description of the target nucleus structure, where dynamic vibrations are considered as perturbations of the rigid rotor underlying structure. OMP parameters that show a smooth energy dependence and energy independent geometry were determined from fits to the available experimental database (including strength functions and scattering radius) for neutron and proton scattering. The energy range 0.001-200 MeV is covered. Derived high-quality OMP is used to calculate the reaction cross section and corresponding theoretical uncertainties in nucleon-induced reactions on U-238. Theoretical calculations are compared with available results derived from existing experimental data on total cross-sections and angular distributions measurements based on the Wick's limit. Reduction of the uncertainty of the calculated reaction cross-section for neutron-induced reactions on 238U is discussed. (author)
Stochastic Correlation Model of Galactic Bulge Velocity Dispersions and Central Black Holes Masses
Dokuchaev, V. I.; Eroshenko, Yu. N.
2002-01-01
We consider the cosmological model in which a part of the Universe \\Omega_h\\sim 10^-5 is in the form of primordial black holes with mass \\sim 10^5M_\\odot. These primordial black holes would be centers for growing protogalaxies which experienced multiple mergers with ordinary galaxies. This process of galaxies formation is accompanied by the merging of central black holes in the galactic nuclei. It is shown that recently discovered correlations between the central black holes and bulges of gal...
Primordial black hole formation from an axion-like curvaton model
Kawasaki, Masahiro(Institute for Cosmic Ray Research, the University of Tokyo, Chiba, 277-8582, Japan); Kitajima, Naoya; Yanagida, Tsutomu T.
2012-01-01
We argue that the existence of the cold dark matter is explained by primordial black holes.We show that a significant number of primordial black holes can be formed in an axion-like curvaton model, in which the highly blue-tilted power spectrum of primordial curvature perturbations is achieved.It is found that the produced black holes with masses $\\sim 10^{20} -10^{38} \\mathrm{g}$ account for the present cold dark matter.We also argue the possibility of forming the primordial black holes with...
Numerical models of black body dominated GRBs: II. Emission properties
Cuesta-Martínez, Carlos F; Mimica, Petar; Thöne, Christina C; de Ugarte-Postigo, Antonio
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated (BBD) gamma-ray bursts (GRBs), long lasting events characterized by the presence of a significant thermal component trailing the GRB prompt emission, and also by an absence of a traditional afterglow. GRB 101225A, the Christmas Burst, is a prototype of such class. It has been suggested that BBD-GRBs could be observed after a merger in a binary system consisting of a neutron star and a Helium core of a main sequence star. Using detailed relativistic hydrodynamic numerical simulations we model the propagation of ultrarelativistic jets through the environments created by such mergers. In this paper we focus on explaining the emission properties of the jet evolution computing the whole radiative signature (both thermal and non-thermal) of the jet dynamical evolution. A comprehensive parameter study of the jet/environment interaction has been performed and synthetic spectra and light curves are compared with the observational data...
A review of the microscopic modeling of the 5-dim. black hole of IIB string theory
Indian Academy of Sciences (India)
Spenta R Wadia
2001-01-01
We review the theory of the microscopic modeling of the 5-dim. black hole of type IIB string theory in terms of the 1-5 brane system. A detailed discussion of the low energy effective Lagrangian of the brane system is presented and the black hole micro-states are identiﬁed. These considerations are valid in the strong coupling regime of supergravity due to the non-renormalization of the low energy dynamics in this model. Using Maldacena duality and standard statistical mechanics methods one can account for black hole thermodynamics and calculate the absorption cross section and the Hawking radiation rates. Hence, at least in the case of this model black hole, since we can account for black hole properties within a unitary theory, there is no information paradox.
SAKATA, Ken; Hoque, Azharul; Hirai, Tomokazu; TSUKAGUCHI, Daisuke; TOMARU, Mayuko; Suzuki, Keiichi; Oikawa, Takuro
2004-01-01
Genetic parameters of body weight at the start of fattening (BSF), carcass weight (CWT), subcutaneous fat thickness (SFT), rib thickness (RBT), meat quality grade (MQG), beef marbling score (BMS) and rib eye area (REA) in Japanese Black cattle were estimated. The effects of genetic and environmental factors on fattening performance and carcass quality traits of the progeny were also analyzed. The averages of BSF, CWT, SFT, RBT and REA were 189 kg, 408 kg, 24.9 mm, 69.3 mm and 47.5 cm^2, respe...
Sima, Jozef; Sukenik, Miroslav; Vanko, Julius
2000-01-01
In the model of Expansive Nondecelerative Universe, black hole cannot totally evaporate via quantum evaporation process proposed by Hawking. In a limiting case, an equilibrium of gravitation creation and black hole evaporation can be reached keeping the surface of its horizon constant. This conclusion is in accordance with the second law of thermodynamics.
Sources of uncertainties in modelling black carbon at the global scale
Vignati, E.; Karl, M.; Krol, M.C.; Wilson, J.; Stier, P.; Cavalli, F.
2010-01-01
Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in th
Brick Wall Model and the Spectrum of a Schwarzschild Black Hole
Institute of Scientific and Technical Information of China (English)
LI Xiang; ZHAO Zheng
2006-01-01
@@ The quantum entropy of a scalar field near a Schwarzschild black hole is investigated by employing the brick-wall model in the grand canonical ensemble. A positive chemical potential is introduced if the cutoff is set to be of order of the Planck length. We also discuss the relation between the chemical potential and the mass quantum of the black hole.
Modeling Lolium perenne L. roots in the presence of empirical black holes
Plant root models are designed for understanding structural or functional aspects of root systems. When a process is not thoroughly understood, a black box object is used. However, when a process exists but empirical data do not indicate its existence, you have a black hole. The object of this re...
A short half-life GFP mouse model for analysis of suprachiasmatic nucleus organization
LeSauter, Joseph; Yan, Lily; Vishnubhotla, Bhavana; Quintero, Jorge E.; Kuhlman, Sandra J.; McMahon, Douglas G.; Silver, Rae
2012-01-01
Period1 (Per1) is one of several clock genes driving the oscillatory mechanisms that mediate circadian rhythmicity. Per1 mRNA and protein are highly expressed in the suprachiasmatic nuclei, which contain oscillator cells that drive circadian rhythmicity in physiological and behavioral responses. We examined a transgenic mouse in which degradable green fluorescent protein (GFP) is driven by the mPer1 gene promoter. This mouse expresses precise free-running rhythms and characteristic light induced phase shifts. GFP protein (reporting Per1 mRNA) is expressed rhythmically as measured by either fluorescence or immunocytochemistry. In addition the animals show predicted rhythms of Per1 mRNA, PER1 and PER2 proteins. The localization of GFP overlaps with that of Per1 mRNA, PER1 and PER2 proteins. Together, these results suggest that GFP reports rhythmic Per1 expression. A surprising finding is that, at their peak expression time GFP, Per1 mRNA, PER1 and PER2 proteins are absent or not detectable in a subpopulation of SCN cells located in the core region of the nucleus. PMID:12576188
A modeling study of notch noise responses of type III units in the gerbil dorsal cochlear nucleus.
Zheng, Xiaohan; Voigt, Herbert F
2006-12-01
A computational model of the neural circuitry of the gerbil dorsal cochlear nucleus (DCN), based on the MacGregor's neuromime model, was used to simulate type III unit (P-cell) responses to notch noise stimuli. The DCN patch model is based on a previous computational model of the cat DCN [Hancock, K. E., and H. F. Voigt. Ann. Biomed. Eng. 27:73-87, 1999]. According to the experimental study of Parsons et al. [Ann. Biomed. Eng. 29:887-896, 2001], the responses of gerbil DCN type III units to notch noise stimuli are similar to those of cat DCN type IV units, which are thought to be spectral notch detectors. This suggests that type III units in the gerbil DCN may serve as spectral notch detectors. In this modeling study, a simplified notch noise response plot--spike discharge rate vs. notch cutoff frequency plot--was used to compare model responses to the experimental results. Parameter estimation and sensitivity analysis of three connection parameters within the DCN patch have been studied and shows the model is robust, providing reasonable fits to the experimental data from 14 of 15 type III units examined.
An Empirical Investigation of the Black-Scholes Model: Evidence from the Australian Stock Exchange
Directory of Open Access Journals (Sweden)
Zaffar Subedar
2007-12-01
Full Text Available This paper evaluates the probability of an exchange traded European call option beingexercised on the ASX200 Options Index. Using single-parameter estimates of factors withinthe Black-Scholes model, this paper utilises qualitative regression and a maximum likelihoodapproach. Results indicate that the Black-Scholes model is statistically significant at the 1%level. The results also provide evidence that the use of implied volatility and a jump-diffusionapproach, which increases the tail properties of the underlying lognormal distribution,improves the statistical significance of the Black-Scholes model.
„BLACK-SCHOLES MODEL USED TO EVALUATE STOCKS OPTIONS”
Directory of Open Access Journals (Sweden)
Turcan Radu Olimpiu Calin
2010-12-01
Full Text Available Partial differential equation, parabolic Black-Scholes type, is used in evaluating equity options, that paying constant and continue dividends or in evaluate options in which interest rate, volatility and dividend are dependent on time.
On the use of the Black & Scholes model in a stochastic interest rate economy
Krister Rindell
1993-01-01
This paper examines the pelformance of the Black & Scholes (1973) model for pricing of European style stock options in a stochastic interest rate economy. Throughout the paper we assume that Jarrow"s (1988) version of the Merton (1973) model correctly describes the reality. We examine the implications of two standard estimation methods of the value of the volatility parameter in the Black & Scholes model, the historical estimate method and the implied value method, respectively. Specific form...
Where are all the gravastars? Limits upon the gravastar model from accreting black holes
International Nuclear Information System (INIS)
The gravastar model, which postulates a strongly correlated thin shell of anisotropic matter surrounding a region of anti-de Sitter space, has been proposed as an alternative to black holes. We discuss constraints that present-day observations of well-known black hole candidates place on this model. We focus upon two black hole candidates known to have extraordinarily low luminosities: the supermassive black hole in the galactic centre, Sagittarius A*, and the stellar-mass black hole, XTE J1118 + 480. We find that the length scale for modifications of the type discussed in Chapline et al (2003 Int. J. Mod. Phys. 18 3587-90) must be sub-Planckian
Institute of Scientific and Technical Information of China (English)
Ruozhuo Liu; Shengyuan Yu; Fengpeng Li; Enchao Qiu
2012-01-01
Cortical spreading depression can trigger migraine with aura and activate the trigeminal vascular system. To examine gene expression profiles in the spinal trigeminal nucleus in rats following cortical spreading depression-induced migraine with aura, a rat model was established by injection of 1 M potassium chloride, which induced cortical spreading depression. DNA microarray analysis revealed that, compared with the control group, the cortical spreading depression group showed seven upregulated genes-myosin heavy chain 1/2, myosin light chain 1, myosin light chain (phosphorylatable, fast skeletal muscle), actin alpha 1, homeobox B8, carbonic anhydrase 3 and an unknown gene. Two genes were downregulated-RGD1563441 and an unknown gene. Real-time quantitative reverse transcription-PCR and bioinformatics analysis indicated that these genes are involved in motility, cell migration, CO2 /nitric oxide homeostasis and signal transduction.
Brozoski, Thomas Jeffrey; Wisner, Kurt W; Sybert, Lauren T; Bauer, Carol A
2012-02-01
Animal experiments suggest that chronic tinnitus ("ringing in the ears") may result from processes that overcompensate for lost afferent input. Abnormally elevated spontaneous neural activity has been found in the dorsal cochlear nucleus (DCN) of animals with psychophysical evidence of tinnitus. However, it has also been reported that DCN ablation fails to reduce established tinnitus. Since other auditory areas have been implicated in tinnitus, the role of the DCN is unresolved. The apparently conflicting electrophysiological and lesion data can be reconciled if the DCN serves as a necessary trigger zone rather than a chronic generator of tinnitus. The present experiment used lesion procedures identical to those that failed to decrease pre-existing tinnitus. The exception was that lesions were done prior to tinnitus induction. Young adult rats were trained and tested using a psychophysical procedure shown to detect tinnitus. Tinnitus was induced by a single unilateral high-level noise exposure. Consistent with the trigger hypothesis, bilateral dorsal DCN lesions made before high-level noise exposure prevented the development of tinnitus. A protective effect stemming from disruption of the afferent pathway could not explain the outcome because unilateral lesions ipsilateral to the noise exposure did not prevent tinnitus and unilateral lesions contralateral to the noise exposure actually exacerbated the tinnitus. The DCN trigger mechanism may involve plastic circuits that, through loss of inhibition, or upregulation of excitation, increase spontaneous neural output to rostral areas such as the inferior colliculus. The increased drive could produce persistent pathological changes in the rostral areas, such as high-frequency bursting and decreased interspike variance, that comprise the chronic tinnitus signal. PMID:21969021
Kaur, Arshdeep; Chopra, Sahila; Gupta, Raj K.
2014-08-01
The compound nucleus (CN) fusion/formation probability PCN is defined and its detailed variations with the CN excitation energy E*, center-of-mass energy Ec .m., fissility parameter χ, CN mass number ACN, and Coulomb interaction parameter Z1Z2 are studied for the first time within the dynamical cluster-decay model (DCM). The model is a nonstatistical description of the decay of a CN to all possible processes. The (total) fusion cross section σfusion is the sum of the CN and noncompound nucleus (nCN) decay cross sections, each calculated as the dynamical fragmentation process. The CN cross section σCN is constituted of evaporation residues and fusion-fission, including intermediate-mass fragments, each calculated for all contributing decay fragments (A1, A2) in terms of their formation and barrier penetration probabilities P0 and P. The nCN cross section σnCN is determined as the quasi-fission (qf) process, where P0=1 and P is calculated for the entrance-channel nuclei. The DCM, with effects of deformations and orientations of nuclei included in it, is used to study the PCN for about a dozen "hot" fusion reactions forming a CN of mass number A ˜100 to superheavy nuclei and for various different nuclear interaction potentials. Interesting results are that PCN=1 for complete fusion, but PCNPCN≪1 due to the nCN contribution, depending strongly on different parameters of the entrance-channel reaction but found to be independent of the nuclear interaction potentials used.
Sources of uncertainties in modelling Black Carbon at the global scale
Directory of Open Access Journals (Sweden)
F. Cavalli
2009-11-01
Full Text Available Our understanding of the global black carbon cycle is essentially qualitative due to uncertainties in our knowledge of the properties of black carbon. This work investigates uncertainties related to modelling black carbon: due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and due to the uncertainties in the definition and quantification of observed black carbon, which propagate through to both the emission inventories, and the measurements used for the model evaluation.
The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering black carbon as bulk aerosol and a simple treatment in the removal and (ii a more complete description of microphysical aging within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol. In the first approach a fixed 70% of black carbon is scavenged in clouds and removed when rain is present. The second leads to a global average of 40% black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, showing that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude.
期货期权的多维Black-Scholes模型%Multi-dimensional Black-Scholes model on future option
Institute of Scientific and Technical Information of China (English)
薛红
2001-01-01
建立了具有变系数的期货期权的多维Black-Scholes模型.利用倒向随机微分方程和鞅方法,直接得到欧式期货未定权益的一般定价公式以及套期保值策略.由此给出了欧式期货看涨期权与看跌期权的定价公式与套期保值策略.%Multi-dimensional Black-Scholes model with non-constant coefficients on future option is established in this paper.The pricing formula and hedging strategy of European Future contingent claim are obtained by back-ward stochastic different equation and martingale method.In view of the result,the pricing formula and hedging strategy of European Future call and put option are given.
Unitarity of black hole evaporation in final-state projection models
Lloyd, Seth; Preskill, John
2014-08-01
Almheiri et al. have emphasized that otherwise reasonable beliefs about black hole evaporation are incompatible with the monogamy of quantum entanglement, a general property of quantum mechanics. We investigate the final-state projection model of black hole evaporation proposed by Horowitz and Maldacena, pointing out that this model admits cloning of quantum states and polygamous entanglement, allowing unitarity of the evaporation process to be reconciled with smoothness of the black hole event horizon. Though the model seems to require carefully tuned dynamics to ensure exact unitarity of the black hole S-matrix, for a generic final-state boundary condition the deviations from unitarity are exponentially small in the black hole entropy; furthermore observers inside black holes need not detect any deviations from standard quantum mechanics. Though measurements performed inside old black holes could potentially produce causality-violating phenomena, the computational complexity of decoding the Hawking radiation may render the causality violation unobservable. Final-state projection models illustrate how inviolable principles of standard quantum mechanics might be circumvented in a theory of quantum gravity.
Formation of a galaxy with a central black hole in the Lemaitre-Tolman model
Krasinski, A; Krasinski, Andrzej; Hellaby, Charles
2004-01-01
We construct two models of the formation a galaxy with a central black hole, starting from a small initial fluctuation at recombination. This is an application of previously developed methods to find a Lemaitre-Tolman model that evolves from a given initial density or velocity profile to a given final density profile. We show that the black hole itself could be either a collapsed object, or a non-vacuum generalisation of a full Schwarzschild-Kruskal-Szekeres wormhole. Particular attention is paid to the black hole's apparent and event horizons.
Poon, Desmond Hin Lun
2009-01-01
This project investigates the underlying properties of the Black-Scholes option pricing model and unveils some of its limitations. We investigate its characteristics by employing historical S&P500 data on a number of options transactions and evaluate its assumptions in the light of market data . Knowing the outlined limitations of Black-Scholes, we will then study the effects of using a trinomial tree to approximate the Black-Scholes model as well as counter the weakness by developing a m...
Black hole mass and binary model for BL Lac object OJ 287
Liu, F. K.; Wu, Xue-Bing
2002-01-01
Recent intensive observations of the BL Lac object OJ 287 raise a lot of questions on the models of binary black holes, processing jets, rotating helical jets and thermal instability of slim accretion disks. After carefully analyzing their radio flux and polarization data, Valtaoja et al. (\\cite{valtaoja00}) propose a new binary model. Based on the black hole mass of $4 \\times 10^8 {\\rm M_\\odot}$ estimated with the tight correlations of the black hole masses and the bulge luminosity or centra...
Hawking Radiation of a Kaluza-Klein Black Hole Described by Landauer Transport Model
Institute of Scientific and Technical Information of China (English)
兰小刚; 韦联福
2012-01-01
We investigate the Hawking radiation of a Kaluza-Klein black hole by using one-dimensional(1D),non-equilibrium,Landauer transport model.The derived Hawking radiation temperature is in consistence with that obtained by using the usual anomaly method.With the Landauer transport model,we calculate the entropy flow out of the Kaluza-Klein black hole and the relevant entropy production rate.How these quantities depending on the physical parameters of the black hole is also discussed.
Madanian, H.; Cravens, T. E.; Rahmati, A.; Goldstein, R.; Burch, J.; Eriksson, A. I.; Edberg, N. J. T.; Henri, P.; Mandt, K.; Clark, G.; Rubin, M.; Broiles, T.; Reedy, N. L.
2016-06-01
Observations of the coma near the nucleus of comet 67P/Churyumov-Gerasimenko (67P) made by the IES (Ion and Electron Sensor) instrument onboard the Rosetta Orbiter during late 2014 showed that electron fluxes greatly exceeded solar wind electron fluxes. The IES is part of the Rosetta Plasma Consortium. This paper reports on electron energy spectra measured by IES near the nucleus as well as approximate densities and average energies for the suprathermal electrons when the comet was at a heliocentric distance of about 3 AU. Comparisons are made with electron densities measured by other instruments. The high electron densities observed (e.g., ne ≈ 10-100 cm-3) must be associated with the cometary ion density enhancement created mainly by the photoionization of cometary gas by solar radiation; there are other processes that also contribute. Quasineutrality requires that the electron and ion densities be the same, and under certain conditions an ambipolar electric field is required to achieve quasi-neutrality. We present the results of a test particle model of cometary ion pickup by the solar wind and a two-stream electron transport code and use these results to interpret the IES data. We also estimate the effects on the electron spectrum of a compression of the electron fluid parcel. The electrons detected by IES can have energies as high as about 100-200 eV near the comet on some occasions, in which case the hot electrons can significantly enhance ionization rates of neutrals via impact ionization.
International Nuclear Information System (INIS)
This work concerns the study of light fragment production at small angles in Ar + Nucleus collisions with the Diogene detector. After a brief review of the Relativistic Heavy Ion collisions, we describe the Diogene detector; we study experimental analysis in particular the simulation of the experimental filter. We analyse the correlations between the multiplicities in the central chamber and in the plastic wall, and we determine differential production cross sections of light fragments at small angles. Then, we compare experimental production cross sections of Z = 1 fragment with theoretical predictions from theoretical models: the thermodynamical model, the Intranuclear Cascade model and the theory of Quantum Molecular Dynamics (QMD). The thermodynamical model allows us to confirm the existence of two sources: the projectile remnant the participant region. We have extracted apparent temperatures which confirm a low excitation energy of the projectile remnant. With the Intranuclear Cascade, we simulate Ar + (Ca,Nb) reactions at 200 and 400 A.MeV. A qualitative description is only obtained. With QMD, we consider two systems: Ar + (Ca,Nb) at 400 and 600 A.MeV, with different impact parameters and with two equations of state (soft and hard). The comparison between experimental data and theoretical data shows a good qualitative agreement. The quantitative agreement depends of centrality of the collisions, and we note a sensitivity of the results to the equation of state for central asymetric collisions, favouring a hard equation of state
Integrable models, degenerate horizons and AdS_2 black holes
J. Cruz; Fabbri, A; Navarro, D. J.; Navarro-Salas, J.; Navarro, P.
1999-01-01
The near extremal Reissner-Nordstrom black holes in arbitrary dimensions ca be modeled by the Jackiw-Teitelboim (JT) theory. The asymptotic Virasoro symmetry of the corresponding JT model exactly reproduces, via Cardy's formula, the deviation of the Bekenstein-Hawking entropy of the Reissner-Nordstrom black holes from extremality. We also comment how can we extend this approach to investigate the evaporation process.
How to hedge Asian options in fractional Black-Scholes model
Tikanmäki, Heikki
2011-01-01
We prove change of variables formulas [It\\^o formulas] for both arithmetic and geometric averages of geometric fractional Brownian motion. They are valid for all convex functions, not only for smooth ones. Moreover, they can be used for obtaining hedges (but not prices) for Asian options in fractional Black-Scholes model. We get explicit hedges in some cases where explicit hedges are not known even in the ordinary Black-Scholes model.
An Empirical Investigation of the Black-Scholes Model: Evidence from the Australian Stock Exchange
Zaffar Subedar; Dionigi Gerace; Scott McKenzie
2007-01-01
This paper evaluates the probability of an exchange traded European call option beingexercised on the ASX200 Options Index. Using single-parameter estimates of factors withinthe Black-Scholes model, this paper utilises qualitative regression and a maximum likelihoodapproach. Results indicate that the Black-Scholes model is statistically significant at the 1%level. The results also provide evidence that the use of implied volatility and a jump-diffusionapproach, which increases the tail proper...
Robust option replication for a Black-Scholes model extended with nondeterministic trends
John G. M. Schoenmakers; Peter E. Kloeden
1999-01-01
Statistical analysis on various stocks reveals long range dependence behavior of the stock prices that is not consistent with the classical Black and Scholes model. This memory or nondeterministic trend behavior is often seen as a reflection of market sentiments and causes that the historical volatility estimator becomes unreliable in practice. We propose an extension of the Black and Scholes model by adding a term to the original Wiener term involving a smoother process which accounts for th...
Sources of uncertainties in modelling black carbon at the global scale
Vignati, E.; Karl, M; M. Krol; Wilson, J.(School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom); Stier, P; F. Cavalli
2010-01-01
Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the...
Van der Vegte, W.F.; Horváth, I.; Rusák, Z.
2009-01-01
We introduce a methodology for modelling and simulating fully virtual human-artefact systems, aiming to resolve two issues in virtual prototyping: (i) integration of distinct modelling and simulation approaches, and (ii) extending the deployability of simulations towards conceptual design. We are go
Aligned spin neutron star-black hole mergers: a gravitational waveform amplitude model
Pannarale, Francesco; Kyutoku, Koutarou; Lackey, Benjamin D; Shibata, Masaru
2015-01-01
The gravitational radiation emitted during the merger of a black hole with a neutron star is rather similar to the radiation from the merger of two black holes when the neutron star is not tidally disrupted. When tidal disruption occurs, gravitational waveforms can be broadly classified in two groups, depending on the spatial extent of the disrupted material. Extending previous work by some of us, here we present a phenomenological model for the gravitational waveform amplitude in the frequency domain encompassing the three possible outcomes of the merger: no tidal disruption, "mild" and "strong" tidal disruption. The model is calibrated to 134 general-relativistic numerical simulations of binaries where the black hole spin is either aligned or antialigned with the orbital angular momentum. All simulations were produced using the SACRA code and piecewise polytropic neutron star equations of state. The present model can be used to determine when black-hole binary waveforms are sufficient for gravitational-wave...
An Introduction to the Interacting Boson Model of the Atomic Nucleus, Part I
Pfeifer, Walter
2002-01-01
This work introduces to the Interacting Boson Model, which was created in 1974 by F. Iachello and A. Arima and then extend by numerous papers. Many-body configurations with s- and d-boson states are described and creation- and annihilation-operators for bosons are introduced. States with defined angular momentum are dealt with and the Hamilton operator of the IBM1-model is expressed in terms of Casimir operators. Level energies and electromagnetic transition probabilities are compared with measured data. A short introduction to Lie algebras and their application to the IBM1-model are given. In the IBM2-model protons and neutrons are treated separately and in IBFM single nucleons are added to the boson model. Comparison with experimental results.
An Introduction to the Interacting Boson Model of the Atomic Nucleus. Part II
Pfeifer, Walter
2002-01-01
This work introduces to the Interacting Boson Model, which was created in 1974 by F. Iachello and A. Arima and then extended by numerous papers. Many-body configurations with s- and d-boson states are described and creation- and annihilation-operators for bosons are introduced. States with defined angular momentum are dealt with and the Hamilton operator of the IBM1-model is expressed in terms of Casimir operators. Level energies and electromagnetic transition probabilities are compared with measured data. A short introduction to Lie algebras and their application to the IBM1-model are given. In the IBM2-model protons and neutrons are treated separately and in IBFM single nucleons are added to the boson model. Comparison with experimental results.
Directory of Open Access Journals (Sweden)
Kaplan Abdullah
2015-01-01
Full Text Available Implementation of projects of new generation nuclear power plants requires the solving of material science and technological issues in developing of reactor materials. Melts of heavy metals (Pb, Bi and Pb-Bi due to their nuclear and thermophysical properties, are the candidate coolants for fast reactors and accelerator-driven systems (ADS. In this study, α, γ, p, n and 3He induced fission cross section calculations for 209Bi target nucleus at high-energy regions for (α,f, (γ,f, (p,f, (n,f and (3He,f reactions have been investigated using different fission reaction models. Mamdouh Table, Sierk, Rotating Liquid Drop and Fission Path models of theoretical fission barriers of TALYS 1.6 code have been used for the fission cross section calculations. The calculated results have been compared with the experimental data taken from the EXFOR database. TALYS 1.6 Sierk model calculations exhibit generally good agreement with the experimental measurements for all reactions used in this study.
International Nuclear Information System (INIS)
Active galactic nuclei (AGNs) are occasionally seen in pairs, suggesting that tidal encounters are responsible for the accretion of material by both central supermassive black holes (BHs). In Paper I of this series, we selected a sample of AGN pairs with projected separations rp –170 kpc and velocity offsets –1 from the Seventh Data Release of the Sloan Digital Sky Survey and quantified their frequency. In this paper, we address the BH accretion and recent star formation properties in their host galaxies. AGN pairs experience stronger BH accretion, as measured by their [O III] λ5007 luminosities (corrected for contribution from star formation) and Eddington ratios, than do control samples of single AGNs matched in redshift and host-galaxy stellar mass. Their host galaxies have stronger post-starburst activity and younger mean stellar ages, as indicated by stronger Hδ absorption and smaller 4000 Å break in their spectra. The BH accretion and recent star formation in the host galaxies both increase with decreasing projected separation in AGN pairs, for rp ∼–170 kpc. The intensity of BH accretion, the post-starburst strength, and the mean stellar ages are correlated between the two AGNs in a pair. The luminosities and Eddington ratios of AGN pairs are correlated with recent star formation in their host galaxies, with a scaling relation consistent with that observed in single AGNs. Our results suggest that galaxy tidal interactions enhance both BH accretion and host-galaxy star formation in close AGN pairs, even though the majority of low-redshift AGNs are not coincident with on-going interactions.
Application of black-box models to HVAC systems for fault detection
Peitsman, H.C.; Bakker, V.E.
1996-01-01
This paper describes the application of black-box models for fault detection and diagnosis (FDD) in heating, ventilat-ing, and air-conditioning (HVAC) systems. In this study, mul-tiple-input/single-output (MISO) ARX models and artificial neural network (ANN) models are used. The ARX models are exami
An Administrative Model for Serving Exceptional Black Children.
Wright, Katie Harper
Two poor inner city predominantly Black school districts (East St. Louis and Lovejoy, Illinois) entered into a joint agreement to enhance delivery of special education services to their children. Initial mistrust began to give way when a common philosophy was reached. Approaches developed included diagnostic and prescriptive teaching and…
One-shot decoupling and Page curves from a dynamical model for black hole evaporation
Bradler, Kamil
2015-01-01
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to the Hawking radiation. An explicit numerical calculation of the discretized path integral of the S-matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction.
An Improved Thin Film Brick-Wall Model of Black Hole Entropy
Institute of Scientific and Technical Information of China (English)
LIU Wen-Biao; ZHAO Zheng
2001-01-01
We improve the brick-wall model to take only the contribution of a thin film near the event horizon into account. This improvement not only gives us a satisfactory result, but also avoids some drawbacks in the original brick wall method such as the little mass approximation, neglecting logarithm term, and taking the term L3 as the contribution of the vacuum surrounding a black hole. It is found that there is an intrinsic relation between the event horizon and the entropy. The event horizon is the characteristic of a black hole, so the entropy calculating of a black hole is also naturally related to its horizon.
Multidimensional extremal dilatonic black holes in string-like model with cosmological term
Ivashchuk, V D
1996-01-01
A string-like model with the "cosmological constant" \\Lambda is considered. The Maki-Shiraishi multi-black-hole solution \\cite{MS1} is generalized to space-times with a Ricci-flat internal space. For \\Lambda = 0 the obtained solution in the one-black-hole case is shown to coincide with the extreme limit of the charged dilatonic black hole solution \\cite{BI,BM}. The Hawking temperature T_H for the solution \\cite{BI,BM} is presented and its extreme limit is considered. For the string value of dilatonic coupling the temperature T_H does not depend upon the internal space dimension.
International Nuclear Information System (INIS)
A Monte Carlo simulation method is presented that can, to an accuracy of a few percent, calculate the effects of a dusty coma on the total energy input to the cometary nucleus. This method treats nonconservative nonisotropic scattering, as well as the reflection from the nucleus surface. Results are presented as a function of the optical thickness of the dust column in the sun-comet axis. The total energy input to the nucleus appears to be only weakly dependent on the opacity of the coma, the radial distribution of the dust, or the details of the extinction processes. 18 references
Neutron Pairing Correlations in an {α}-{n}-{n} Three-Cluster Model of the {6}He Nucleus
Kamada, H.; Furuya, J.; Yamaguchi, M.; Oryu, S.
2016-04-01
An {α}- n- n three-cluster model of the {^6}He nucleus is studied by solving the Faddeev equations, where the cluster potential between {α} and n takes into account the Pauli exclusion correction, using the Fish-Bone Optical Model (Schmid in Z Phys A 297:105, 1980). The resulting binding energy of the ground state ({0^+}) is 0.831 MeV and the resonance energy of the first excited state ({2^+}), 0.60-i0.012 MeV, is extracted from the three-cluster break-up threshold. These theoretical values are in reasonable agreement with the experimental data: 0.973 MeV and 0.824-i0.056 MeV, respectively. In order to investigate the structure of these states, we calculate the angle density matrix for the {angle n_1 α n_2} angle in the triangle formed by the three clusters. The angle density matrix of the ground state has two peaks and the configuration of {0^+} wave function corresponding to the peaks constitutes a mixture of an acute-angled triangle structure and an obtuse-angled one. This finding is consistent with the former result from a variational approach (Hagino and Sagawa in Phys Rev C 72:044321, 2005). On the other hand, in the case of {2^+} state only a single peak is obtained.
International Nuclear Information System (INIS)
In the Cloudy Bag Model hadrons are treated as quarks confined in an M.I.T. bag that is surrounded by a cloud of pions. Computations of the charge and magnetism distributions of nucleons and baryons, pion-nucleon scattering, and the strong and electromagnetic decays of mesons are discussed. Agreement with experimental results is excellent if the nucleon bag radius is in the range between 0.8 and 1.1 fm. Underlying qualitative reasons which cause the pionic corrections to be of the obtained sizes are analyzed. If bags are of such reasonably large sizes, nucleon bags in nuclei will often come into contact. As a result one needs to consider whether explicit quark degrees of freedom are relevant for Nuclear Physics. To study such possibilities a model which treats a nucleus as a collection of baryons, pions and six-quark bags is discussed. In particular, the short distance part of a nucleon-nucleon wave function is treated as six quarks confined in a bag. This approach is used to study the proton-proton weak interaction, the asymptotic D to S state ratio of the deuteron, the pp → dπ reaction, the charge density of /sup 3/He, magnetic moments of /sup 3/He and /sup 3/H and, the /sup 3/He-/sup 3/H binding energy difference. It is found that quark effects are very relevant for understanding nuclear properties
Magnetically charged regular black hole in a model of nonlinear electrodynamics
Ma, Meng-Sen
2015-01-01
We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). "Physically" here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which we know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.
The Ramsauer model for the total cross sections of neutron nucleus scattering
Gowda, R. S.; Suryanarayana, S. S. V.; Ganesan, S
2005-01-01
Theoretical study of systematics of neutron scattering cross sections on various materials for neutron energies up to several hundred MeV are of practical importance. In this paper, we analysed the experimental neutron scattering total cross sections from 20MeV to 550MeV using Ramsauer model for nuclei ranging from Be to Pb.
Neutrino nucleus reactions at high energies within the GiBUU model
Lalakulich, O; Leitner, T; Mosel, U
2011-01-01
The GiBUU model, which implements all reaction channels relevant at medium neutrino energy, is used to investigate the neutrino and antineutrino scattering on iron. Results for integrated cross sections are compared with NOMAD and MINOS data. It is shown, that final state interaction can noticeably change the spectra of the outgoing hadrons. Predictions for the Miner$\
Neutrino nucleus cross sections
Athar, M Sajjad; Singh, S K; Vacas, M J Vicente
2008-01-01
We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $\\Delta $- dominance model taking into account the renormalization of $\\Delta$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.
A Unified Model of Magnetic Extraction of Spin Energy from a Black Hole
Institute of Scientific and Technical Information of China (English)
汪定雄; 肖看; 雷卫华
2002-01-01
A unified model of magnetic extraction of spin energy from a black hole is discussed based on the theory of black hole magnetosphere. The magnetic extracting power is expressed by a unified formula, which is applicable to both the Blandford-Znajek (BZ) process and the magnetic coupling (MC) process. The strength and characteristics of the BZ power and the MC power are compared in detail. In addition, the impedance matching condition for the BZ power is extended to the more general case.
Antioxidant effect of garlic and aged black garlic in animal model of type 2 diabetes mellitus
Lee, Young-Min; Gweon, Oh-Cheon; Seo, Yeong-Ju; Im, Jieun; Kang, Min-Jung; Kim, Myo-Jeong; Kim, Jung-In
2009-01-01
Hyperglycemia in the diabetic state increases oxidative stress and antioxidant therapy can be strongly correlated with decreased risks for diabetic complications. The purpose of this study is to determine antioxidant effect of garlic and aged black garlic in animal model of type 2 diabetes. The antioxidant activity of garlic and aged black garlic was measured as the activity in scavenging free radicals by the trolox equivalent antioxidant capacity (TEAC) assay. Three week-old db/db mice were ...
On the derivation and solution of the black-scholes option pricing model
David CHAPPELL
1992-01-01
The derivation and solution of the celebrated Black-Scholes Option Pricing Formula is set out in rather more detail than has appeared in the literature so far. One problem with the Black-Scholes analysis is that the mathematical skills required in the derivation and particularly in the solution of the model are fairly advanced and probably unfamiliar to most economists. This paper derives the partial differential equation for the call option price and gives full details of its sol...
Changes in the creditability of the Black-Scholes option pricing model due to financial turbulences
Angeli, Andrea; Bonz, Cornelius
2010-01-01
This study examines whether the performance of the Black-Scholes model to price stock index options is influenced by the general conditions of the financial markets. For this purpose we calculated the theoretical values of 5814 options (3366 put option price observations and 2448 call option price observations) under the Black-Scholes assumptions. We compared these theoretical values with the real market prices in order to put the degree of deviations in two different time windows built aroun...
Solution of the Fractional Black-Scholes Option Pricing Model by Finite Difference Method
Lina Song; Weiguo Wang
2013-01-01
This work deals with the put option pricing problems based on the time-fractional Black-Scholes equation, where the fractional derivative is a so-called modified Riemann-Liouville fractional derivative. With the aid of symbolic calculation software, European and American put option pricing models that combine the time-fractional Black-Scholes equation with the conditions satisfied by the standard put options are numerically solved using the implicit scheme of the finite difference method.
Double folding model analysis of elastic scattering of halo nucleus 11Be from 64Zn
Indian Academy of Sciences (India)
M Hemalatha
2014-05-01
Calculations of elastic scattering cross-sections for 9,10,11Be+64Zn at near-Coulomb barrier energy have been performed using a potential obtained from the double folding model and are compared with the experiment. In the framework of the double folding model, the nuclear matter densities of 9,10,11Be projectiles and a 64Zn target are folded with the complex energydependent effective M3Y interaction. The angular distributions of the differential cross-section for 9,10Be scattering from 64Zn at $E_{c.m.} ≈$24.5 MeV agree remarkably well with the data, while in case of 11Be, calculations show a Coulomb–nuclear interference peak which is not observed in the data.
Microscopic shell-model description of an exotic nucleus ^{16}C
Fujii, S; Mizusaki, T; Otsuka, T; Sebe, T
2007-01-01
The structure of neutron-rich carbon isotopes ^{14, 16, 18}C is described by introducing a new microscopic method of the no-core shell-model type. The model space is composed of the 0s, 0p, 1s0d, and 1p0f shells. The effective interaction is microscopically derived from the CD-Bonn potential and the Coulomb force through a unitary transformation. Calculated low-lying energy levels of ^{16}C agree well with the experiment. The B(E2;2_{1}^{+} \\to 0_{1}^{+}) value is calculated with the bare charges. The anomalously hindered B(E2) value for ^{16}C, measured recently, is reproduced.
Wilkinson, Matthew B.; Xiao, Guanghua; Kumar, Arvind; LaPlant, Quincey; Renthal, William; Sikder, Devanjan; Kodadek, Thomas J; Nestler, Eric J.
2009-01-01
Though it is a widely studied psychiatric syndrome, major depressive disorder remains a poorly understood illness, especially with regard to the disconnect between treatment initiation and the delayed onset of clinical improvement. We have recently validated chronic social defeat stress in mice as a model in which a depression-like phenotype is reversed by chronic, but not acute, antidepressant administration. Here, we use ChIP-chip assays—chromatin immunoprecipitation (ChIP) followed by geno...
Juárez, Claudia; Morgado, Elvira; Stefan M. Waliszewski; Armando J. Martínez; Meza, Enrique; Caba, Mario
2012-01-01
Rabbit pups represent a natural model of food anticipatory activity (FAA). FAA is the behavioral output of a putative food entrainable oscillator (FEO). It had been suggested that the FEO is comprised of a distributed system of clocks that work in concert in response to gastrointestinal input by food. Scheduled food intake synchronizes several nuclei in the brain, and the hypothalamus has received particular attention. On the contrary, brainstem nuclei, despite being among the brain structure...
Energy Technology Data Exchange (ETDEWEB)
Rahim, M.A.; Fakhraddin, S.; Asharabi, H. [Sana' a University, Physics Department, Faculty of Science, Sana' a (Yemen)
2012-08-15
The multiplicity distributions of projectile fragments (PFs) produced in interactions of ({sup 4}He, {sup 12}C, {sup 16}O, {sup 22}Ne and {sup 28}Si) with emulsion (Em) at 4.1-4.5 A GeV/c beam energies, and their dependence on target groups (H, CNO and AgBr) are presented and have been reproduced by using a multi-source thermal model. The dependence of the mean multiplicities on masses of projectile and target nuclei is investigated. The experimental results are compared with the corresponding ones from the theoretically calculated ones. The experimental results agree with theoretical calculations using the multi-source thermal model. (orig.)
Modelling the productivity of Anatolian black pine plantations in Turkey
Directory of Open Access Journals (Sweden)
Şükrü Teoman Güner
2016-01-01
Full Text Available This study was carried out to determine the relationships between height growth (site index of Anatolian black pine (Pinus nigra Arnold. subsp. pallasina (Lamb. Holmboe and site factors of the plantation areas in Turkey. Data were collected from 118 sample plots by taking into consideration the variations of aspect, altitude, slope position, slope degree and site class. A representative tree for the productivity and soil samples were taken at each sample plot. Some chemical and physical properties of soil samples were determined in the laboratory. The relationships between site index values of the trees and site factors including parent material, soil, climate and topography were examined by using correlation, stepwise regression and regression tree analysis. Significant linear relations were found between site index of black pine and site factors being altitude, slope degree, slope position, annual rainfall, precipitation amount in the most drought month, solum depth and bedrock including granite, mica schist and dacite. Explanation variance percentage on the site index of black pine was found 54.4% by using regression tree analysis whereas explained variance become 34.7% by stepwise regression analysis.
Formation of light particles in nucleus-nucleus collisions
International Nuclear Information System (INIS)
The principal experimental results on the yield of the light charged particles in nucleus-nucleus collisions at the low and intermediate energies are reviewed. Inclusive spectra of light particles and their coincidences with the characteristic KX-rays, γ-rays, neutrons, projectile-like fragments, other light particles, fission fragments, and evaporation residues are analyzed. The main theoretical models used for the description of the light particle formation are briefly outlined together with their merits and shortcomings. The unsolved problems of fast light particle formation, in particular, and of nucleus-nucleus interaction dynamics, on the whole, are discussed with the outlooks of new experiments able to clear up some of these problems. (author) 144 refs., 40 figs., 2 tabs
Superdeformed band in the $N = Z+4$ nucleus $^{40}$Ar: A projected shell model analysis
Yang, Ying-Chun; Sun, Yang; Guidry, Mike
2015-01-01
It has been debated whether the experimentally-identified superdeformed rotational band in $^{40}$Ar [E. Ideguchi, et al., Phys. Lett. B 686 (2010) 18] has an axially or triaxially deformed shape. Projected shell model calculations with angular-momentum-projection using an axially-deformed basis are performed up to high spins. Our calculated energy levels indicate a perfect collective-rotor behavior for the superdeformed yrast band. However, detailed analysis of the wave functions reveals that the high-spin structure is dominated by mixed 0-, 2-, and 4-quasiparticle configurations. The calculated electric quadrupole transition probabilities reproduce well the known experimental data and suggest a reduced, but still significant, collectivity in the high spin region. The deduced triaxial deformation parameters are small throughout the entire band, suggesting that triaxiality is not very important for this superdeformed band.
Modeling neutrino-nucleus interactions. Do we need a new paradigm?
Energy Technology Data Exchange (ETDEWEB)
Benhar, Omar [INFN, Sezione di Roma Dipartimento di Fisica, ' Sapienza' Universita di Roma I-00185 Roma (Italy)
2012-08-15
The availability of the double-differential charged-current neutrino cross section, measured by the MiniBooNE collaboration using a carbon target, allows for a systematic comparison of nuclear effects in quasi-elastic electron and neutrino scattering. The results of theoretical studies based on the impulse approximation scheme and state-of-the-art models of the nuclear spectral functions suggest that the electron cross section and the flux averaged neutrino cross sections corresponding to the same target and seemingly comparable kinematical conditions can not be described within the same theoretical scheme using the value of the nucleon axial mass obtained from deuterium measurements. I analyze the assumptions underlying the treatment of electron scattering data, and argue that the development of a new paradigm, suitable for application to processes in which the lepton kinematics is not fully determined, will be required.
M33 A Galaxy with No Supermassive Black Hole
Gebhardt, K; Kormendy, J; Pinkney, J C; Bower, G A; Green, R; Gull, T R; Hutchings, J B; Joseph, C L; Kaiser, M E; Nelson, C H; Richstone, D O; Weistrop, D; Gebhardt, Karl; Lauer, Tod R.; Kormendy, John; Pinkney, Jason; Bower, Gary A.; Green, Richard; Gull, Theodore; Joseph, Chuck; Nelson, Charles H.; Richstone, Douglas; Weistrop, Donna
2001-01-01
Galaxies that contain bulges appear to contain central black holes whose masses correlate with the velocity dispersion of the bulge. We show that no corresponding relationship applies in the pure disk galaxy M33. Three-integral dynamical models fit Hubble Space Telescope WFPC2 photometry and STIS spectroscopy best if the central black hole mass is zero. The upper limit is 1500 M_sun. This is significantly below the mass expected from the velocity dispersion of the nucleus and far below any mass predicted from the disk kinematics. Our results suggest that supermassive black holes are associated only with galaxy bulges and not with their disks or dark halos.
Sources of uncertainties in modelling black carbon at the global scale
Directory of Open Access Journals (Sweden)
E. Vignati
2010-03-01
Full Text Available Our understanding of the global black carbon (BC cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation.
The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of
Black holes and gravitational waves in models of minicharged dark matter
Cardoso, Vitor; Pani, Paolo; Ferrari, Valeria
2016-01-01
In viable models of minicharged dark matter, astrophysical black holes might be charged under a hidden $U(1)$ symmetry and are formally described by the same Kerr-Newman solution of Einstein-Maxwell theory. These objects are unique probes of minicharged dark matter and dark photons. We show that the recent gravitational-wave detection of a binary black-hole coalescence by aLIGO provides various observational bounds on the black hole's charge, regardless of its nature. The pre-merger inspiral phase can be used to constrain the dipolar emission of (ordinary and dark) photons, whereas the detection of the quasinormal modes set an upper limit on the final black hole's charge. By using a toy model of a point charge plunging into a Reissner-Nordstrom black hole, we also show that in dynamical processes the (hidden) electromagnetic quasinormal modes of the final object are excited to considerable amplitude in the gravitational-wave spectrum only when the black hole is nearly extremal. The coalescence produces a burs...
Fractional Black-Scholes Model and Technical Analysis of Stock Price
Directory of Open Access Journals (Sweden)
Song Xu
2013-01-01
Full Text Available In the stock market, some popular technical analysis indicators (e.g., Bollinger bands, RSI, ROC, etc. are widely used to forecast the direction of prices. The validity is shown by observed relative frequency of certain statistics, using the daily (hourly, weekly, etc. stock prices as samples. However, those samples are not independent. In earlier research, the stationary property and the law of large numbers related to those observations under Black-Scholes stock price model and stochastic volatility model have been discussed. Since the fitness of both Black-Scholes model and short-range dependent process has been questioned, we extend the above results to fractional Black-Scholes model with Hurst parameter H>1/2, under which the stock returns follow a kind of long-range dependent process. We also obtain the rate of convergence.
Directory of Open Access Journals (Sweden)
Liu Dongjuan
2012-11-01
Full Text Available Abstract Introduction Post-traumatic stress disorder (PTSD is an anxiety disorder that develops after exposure to a life-threatening traumatic experience. Meta-analyses of the brainstem showed that midsagittal area of the pons was significantly reduced in patients with PTSD, suggesting a potential apoptosis in dorsal raphe nucleus after single-prolonged stress (SPS. The aim of this study is to investigate whether SPS induces apoptosis in dorsal raphe nucleus in PTSD rats, which may be a possible mechanism of reduced volume of pons and density of gray matter. Methods In this study, rats were randomly divided into 1d, 7d and 14d groups after SPS along with the control group. The apoptosis rate was determined using annexin V-FITC/PI double-labeled flow cytometry (FCM. Levels of Cytochrome c (Cyt-C was examined by Western blotting. Expression of Cyt-C on mitochondria in the dorsal raphe nucleus neuron was determined by enzymohistochemistry under transmission electron microscopy (TEM. The change of thiamine monophosphatase (TMP levels was assessed by enzymohistochemistry under light microscope and TEM. Morphological changes of the ultrastructure of the dorsal raphe nucleus neuron were determined by TEM. Results Apoptotic morphological alterations were observed in dorsal raphe nucleus neuron for all SPS-stimulate groups of rats. The apoptosis rates were significantly increased in dorsal raphe nucleus neuron of SPS rats, along with increased release of cytochrome c from the mitochondria into the cytoplasm, increased expression of Cyt-C and TMP levels in the cytoplasm, which reached to the peak of increase 7 days of SPS. Conclusions The results indicate that SPS induced Cyt-C released from mitochondria into cytosol and apoptosis in dorsal raphe nucleus neuron of rats. Increased TMP in cytoplasm facilitated the clearance of apoptotic cells. We propose that this presents one of the mechanisms that lead to reduced volume of pons and gray matter associated
A note on Black-Scholes pricing model for theoretical values of stock options
Edeki, S. O.; Ugbebor, O. O.; Owoloko, E. A.
2016-02-01
In this paper, we consider some conditions that transform the classical Black-Scholes Model for stock options valuation from its partial differential equation (PDE) form to an equivalent ordinary differential equation (ODE) form. In addition, we propose a relatively new semi-analytical method for the solution of the transformed Black-Scholes model. The obtained solutions via this method can be used to find the theoretical values of the stock options in relation to their fair prices. In considering the reliability and efficiency of the models, we test some cases and the results are in good agreement with the exact solution.
Chang, Andrew D; Berges, Victoria A; Chung, Sunho J; Fridman, Gene Y; Baraban, Jay M; Reti, Irving M
2016-06-01
Approximately one quarter of individuals with an autism spectrum disorder (ASD) display self-injurious behavior (SIB) ranging from head banging to self-directed biting and punching. Sometimes, these behaviors are extreme and unresponsive to pharmacological and behavioral therapies. We have found electroconvulsive therapy (ECT) can produce life-changing results, with more than 90% suppression of SIB frequency. However, these patients typically require frequent maintenance ECT (mECT), as often as every 5 days, to sustain the improvement gained during the acute course. Long-term consequences of such frequent mECT started as early as childhood in some cases are unknown. Accordingly, there is a need for alternative forms of chronic stimulation for these patients. To explore the feasibility of deep brain stimulation (DBS) for intractable SIB seen in some patients with an ASD, we utilized two genetically distinct mouse models demonstrating excessive self-grooming, namely the Viaat-Mecp2(-/y) and Shank3B(-/-) lines, and administered high-frequency stimulation (HFS) via implanted electrodes at the subthalamic nucleus (STN-HFS). We found that STN-HFS significantly suppressed excessive self-grooming in both genetic lines. Suppression occurs both acutely when stimulation is switched on, and persists for several days after HFS is stopped. This effect was not explained by a change in locomotor activity, which was unaffected by STN-HFS. Likewise, social interaction deficits were not corrected by STN-HFS. Our data show STN-HFS suppresses excessive self-grooming in two autism-like mouse models, raising the possibility DBS might be used to treat intractable SIB associated with ASDs. Further studies are required to explore the circuitry engaged by STN-HFS, as well as other potential stimulation sites. Such studies might also yield clues about pathways, which could be modulated by non-invasive stimulatory techniques. PMID:26606849
Directory of Open Access Journals (Sweden)
Olga Krupkova
2016-09-01
Full Text Available Organ cultures are practical tools to investigate regenerative strategies for the intervertebral disc. However, most existing organ culture systems induce severe tissue degradation with only limited representation of the in vivo processes. The objective of this study was to develop a space- and cost-efficient tissue culture model, which represents degenerative processes of the nucleus pulposus (NP. Intact bovine NPs were cultured in a previously developed system using Dyneema jackets. Degenerative changes in the NP tissue were induced either by the direct injection of chondroitinase ABC (1–20 U/mL or by the diffusion of interleukin-1 beta (IL-1β and tumor necrosis factor alpha (TNF-α (both 100 ng/mL from the culture media. Extracellular matrix composition (collagens, proteoglycans, water, and DNA and the expression of inflammatory and catabolic genes were analyzed. The anti-inflammatory and anti-catabolic compound epigallocatechin 3-gallate (EGCG, 10 µM was employed to assess the relevance of the degenerative NP model. Although a single injection of chondroitinase ABC reduced the proteoglycan content in the NPs, it did not activate cellular responses. On the other hand, IL-1β and TNF-α significantly increased the mRNA expression of inflammatory mediators IL-6, IL-8, inducible nitric oxide synthase (iNOS, prostaglandin-endoperoxide synthase 2 (PTGS2 and matrix metalloproteinases (MMP1, MMP3, and MMP13. The cytokine-induced gene expression in the NPs was ameliorated with EGCG. This study provides a proof of concept that inflammatory NP cultures, with appropriate containment, can be useful for the discovery and evaluation of molecular therapeutic strategies against early degenerative disc disease.
A noncommutative model for a mini black hole
Energy Technology Data Exchange (ETDEWEB)
Arraut, I; Nowakowski, M [Departamento de Fisica, Universidad de los Andes, Cra.1E No. 18A-10, Bogota (Colombia); Batic, D [Departamento de Matematica, Universidad de los Andes, Cra 1E, No. 18A-10, Bogota (Colombia)
2009-12-21
We analyze the static and spherically symmetric perfect fluid solutions of Einstein field equations inspired by the noncommutative geometry. In the framework of the noncommutative geometry, this solution is interpreted as a mini black hole which has the Schwarzschild geometry outside the event horizon, but whose standard central singularity is replaced by a self-gravitating droplet. The energy-momentum tensor of the droplet is of the anisotropic fluid obeying a nonlocal equation of state. The radius of the droplet is finite and the pressure, which gives rise to the hydrostatic equilibrium, is positive definite in the interior.
A noncommutative model for a mini black hole
International Nuclear Information System (INIS)
We analyze the static and spherically symmetric perfect fluid solutions of Einstein field equations inspired by the noncommutative geometry. In the framework of the noncommutative geometry, this solution is interpreted as a mini black hole which has the Schwarzschild geometry outside the event horizon, but whose standard central singularity is replaced by a self-gravitating droplet. The energy-momentum tensor of the droplet is of the anisotropic fluid obeying a nonlocal equation of state. The radius of the droplet is finite and the pressure, which gives rise to the hydrostatic equilibrium, is positive definite in the interior.
Simple Heuristic Approach to Introduction of the Black-Scholes Model
Yalamova, Rossitsa
2010-01-01
A heuristic approach to explaining of the Black-Scholes option pricing model in undergraduate classes is described. The approach draws upon the method of protocol analysis to encourage students to "think aloud" so that their mental models can be surfaced. It also relies upon extensive visualizations to communicate relationships that are…
Seaton, Eleanor K.; Upton, Rachel; Gilbert, Adrianne; Volpe, Vanessa
2014-01-01
This study examined a moderated mediation model among 314 Black adolescents aged 13-18. The model included general coping strategies (e.g., active, distracting, avoidant, and support-seeking strategies) as mediators and racial identity dimensions (racial centrality, private regard, public regard, minority, assimilationist, and humanist ideologies)…
Modelling anaerobic digestion of concentrated black water and faecal matter in accumulation system
Elmitwalli, T.; Zeeman, G.; Otterpohl, R.
2011-01-01
A dynamic mathematical model based on anaerobic digestion model no. 1 (ADM1) was developed for accumulation (AC) system treating concentrated black water and faecal matter at different temperatures. The AC system was investigated for the treatment of waste(water) produced from the following systems:
Adaptive MPC based on probabilistic black-box input-output model
International Nuclear Information System (INIS)
A novel adaptive model-based predictive-control algorithm is proposed for the control of stable nonlinear dynamic systems. The model of controlled dynamical system is a Gaussian process (GP) model. It is a probabilistic, nonparametric, kernel, black-box model. An evolving GP-modelling method is used for the online model identification. Model-based predictive control utilising such a model results in an adaptive feedback control. The proposed control-method features are illustrated on a simulation example. Key words: evolving Gaussian process model, model-based predictive control, adaptive control
Grégoire, M.; Soetaert, K.E.R.; Nezlin, N.; Kostianoy, A.
2004-01-01
A six-compartment ecosystem model defined by a simple nitrogen cycle is coupled with a general circulation model in the Black Sea so as to examine the seasonal variability of the ecohydrodynamics. Model results show that the annual cycle of the biological productivity of the whole basin is character
Modeling AGN outbursts from supermassive black hole binaries
Directory of Open Access Journals (Sweden)
Tanaka T.
2012-12-01
Full Text Available When galaxies merge to assemble more massive galaxies, their nuclear supermassive black holes (SMBHs should form bound binaries. As these interact with their stellar and gaseous environments, they will become increasingly compact, culminating in inspiral and coalescence through the emission of gravitational radiation. Because galaxy mergers and interactions are also thought to fuel star formation and nuclear black hole activity, it is plausible that such binaries would lie in gas-rich environments and power active galactic nuclei (AGN. The primary difference is that these binaries have gravitational potentials that vary – through their orbital motion as well as their orbital evolution – on humanly tractable timescales, and are thus excellent candidates to give rise to coherent AGN variability in the form of outbursts and recurrent transients. Although such electromagnetic signatures would be ideally observed concomitantly with the binary’s gravitational-wave signatures, they are also likely to be discovered serendipitously in wide-field, high-cadence surveys; some may even be confused for stellar tidal disruption events. I discuss several types of possible “smoking gun” AGN signatures caused by the peculiar geometry predicted for accretion disks around SMBH binaries.
Institute of Scientific and Technical Information of China (English)
ZHANG Jin-jun; SONG Wu; LUO Wen-ying; WEI Ming; SUN Lai-bao; ZOU Xue-nong; LIAO Wei-ming
2011-01-01
Background Nucleus pulposus of intervertebral discs has proinflammatory characteristics that play a key role in neuropathic pain in lumbar herniated intervertebral disc. One of the most commonly used animal models (the traditional model) of non-compressive lumbar hemiated intervertebral disc is created by L4-L5 hemilaminectomy and the application of autologous nucleus pulposus to cover the left L4 and L5 nerve roots in rats. However, such procedures have the disadvantages of excessive trauma and low success rate. We proposed a modified model of non-compressive lumbar herniated intervertebral disc in which only the left L5 dorsal root ganglion is exposed and transplanted with autologous nucleus pulposus following incision of epineurium. We aimed to compare the modified model with the traditional one with regard to trauma and success rate.Methods Thirty Sprague-Dawley male rats were randomized into three groups: sham operation group (n=6). traditional group (n=12), and modified group (n=12). The amount of blood loss and operative time for each group were analyzed. The paw withdrawal threshold of the left hind limb to mechanical stimuli and paw withdrawal latency to heat stimuli were examined from the day before surgery to day 35 after surgery.Results Compared with the traditional group, the modified group had shorter operative time, smaller amount of blood loss, and higher success rate (91.7% versus 58.3%, P ＜0.05). There was no decrease in paw withdrawal latency in any group. The sham operation group had no decrease in postoperative paw withdrawal threshold, whereas the modified and traditional groups had significant reduction in paw withdrawal threshold after surgery (mechanical hyperalgesia).Conclusions Transplantation of nucleus pulposus onto the L5 dorsal root ganglion following incision of epineurium in rats established an improved animal model of non-compressive lumbar herniated intervertebral disc with less trauma and more stable pain ethology.
Photo nuclear energy loss term for muon-nucleus interactions based on xi scaling model of QCD
Roychoudhury, R.
1985-01-01
Extensive air showers (EMC) experiments discovered a significant deviation of the ratio of structure functions of iron and deuteron from unity. It was established that the quark parton distribution in nuclei are different from the corresponding distribution in the nucleus. It was examined whether these results have an effect on the calculation of photo nucleus energy loss term for muon-nucleus nuclear interaction. Though the EMC and SLAC data were restricted to rather large q sq region it is expected that the derivation would persist even in the low q sq domain. For the ratio of iron and deuteron structure function a rather naive least square fit of the form R(x) = a + bx was taken and it is assumed that the formula is valid for the whole q sq region the absence of any knowledge of R(x) for small q sq.
Analysis of ecological transitions in the Black Sea during the last four decades: A modelling study
Akoglu, Ekin; Salihoglu, Baris; Oguz, Temel
2010-05-01
This work investigates the Black Sea ecosystem and the changes it had undergone in the second half of the 20th century from a fisheries perspective using Ecopath, a widely adopted fisheries model. Different states of the Black Sea ecosystem were modeled using 5 simulation scenarios: Simulation 1, represents the quasi-pristine conditions of the Black Sea ecosystem during early 1960's; Simulation 2, represents the over-enrichment period of the ecosystem during early 1980's before the fisheries collapse and the outburst of alien ctenophore Mnemiopsis leidyi; Simulation 3, represents the changes in the ecosystem along with the outburst of Mnemiopsis in 1989; Simulation 4, represents the aftermath effects in the components of the Black Sea ecosystem just after the collapse of the fisheries; and Simulation 5, represents the recovery period of the fish stocks in the very beginning of the 1990's. According to the results of the model runs, it was found that the Black Sea ecosystem in its quasi-pristine conditions during early 1960's was top-down controlled. The piscivorous pelagic fish and dolphins exerted predation pressure on small pelagic fish species and suppressed their over-development. Our findings suggest that after the removal of these top predators from the ecosystem due to fishing and whaling, the small pelagic fish species had the opportunity to thrive themselves along with the over-enrichment of the Black Sea and reached high biomass levels in 1980's. Small pelagic fishes prevailed in the Black Sea ecosystem until the highly debated outburst of alien ctenophore Mnemiopsis leidyi. In 1989, the biomass of small pelagic fish species declined drastically and their population did not recover until the very beginning of 1990's due to various ecological and anthropogenic effects put forward by the outcomes of the simulations.
Aligned spin neutron star-black hole mergers: A gravitational waveform amplitude model
Pannarale, Francesco; Berti, Emanuele; Kyutoku, Koutarou; Lackey, Benjamin D.; Shibata, Masaru
2015-10-01
The gravitational radiation emitted during the merger of a black hole with a neutron star is rather similar to the radiation from the merger of two black holes when the neutron star is not tidally disrupted. When tidal disruption occurs, gravitational waveforms can be broadly classified in two groups, depending on the spatial extent of the disrupted material. Extending previous work by some of us, here we present a phenomenological model for the gravitational waveform amplitude in the frequency domain encompassing the three possible outcomes of the merger: no tidal disruption, and "mild" and "strong" tidal disruption. The model is calibrated to 134 general-relativistic numerical simulations of binaries where the black hole spin is either aligned or antialigned with the orbital angular momentum. All simulations were produced using the SACRA code and piecewise polytropic neutron star equations of state. The present model can be used to determine when black-hole binary waveforms are sufficient for gravitational-wave detection, to extract information on the equation of state from future gravitational-wave observations, to obtain more accurate estimates of black hole-neutron star merger event rates, and to determine the conditions under which these systems are plausible candidates as central engines of gamma-ray bursts and macronovae/kilonovae.
Numerical modeling of the central Black Sea ecosystem functioning during the eutrophication phase
Grégoire, M.; Raick, C.; Soetaert, K.
2008-01-01
A one-dimensional coupled physical-biogeochemical model has been developed to simulate the ecosystem of the central Black Sea at the end of the 1980s when eutrophication and invasion by gelatinous organisms seriously affected the stability and dynamics of the system. The physical model is the General Ocean Turbulence Model (GOTM) and the biogeochemical model describes the foodweb, from bacteria to gelatinous carnivores through 24 state variables including three groups of phytoplankton: diatom...
Notes on non-singular models of black holes
Frolov, Valeri P
2016-01-01
We discuss static spherically symmetric metrics which represent non-singular black holes in four- and higher-dimensional spacetime. We impose a set of restrictions, such as a regularity of the metric at the center $r=0$ and Schwarzschild asymptotic behavior at large $r$. We assume that the metric besides mass $M$ contains an additional parameter $\\ell$, which determines the scale where modification of the solution of the Einstein equations becomes significant. We require that the modified metric obeys the limiting curvature condition, that is its curvature is uniformly restricted by the value $\\sim \\ell^{-2}$. We also make a "more technical" assumption that the metric coefficients are rational functions of $r$. In particular, the invariant $(\
Hannam, Mark
2013-01-01
The inspiral and merger of two orbiting black holes is among the most promising sources for the first (hopefully imminent) direct detection of gravitational waves (GWs), and measurements of these signals could provide a wealth of information about astrophysics, fundamental physics and cosmology. Detection and measurement require a theoretical description of the GW signals from all possible black-hole-binary configurations, which can include complicated precession effects due to the black-hole spins. Modelling the GW signal from generic precessing binaries is therefore one of the most urgent theoretical challenges facing GW astronomy. This article briefly reviews the phenomenology of generic-binary dynamics and waveforms, and recent advances in modelling them.
Models of Kilonova/macronova emission from black hole-neutron star mergers
Kawaguchi, Kyohei; Shibata, Masaru; Tanaka, Masaomi
2016-01-01
Black hole-neutron star mergers are among the promising gravitational-wave sources for ground-based detectors, and gravitational waves from black hole-neutron mergers are expected to be detected in the next few years. Simultaneous detection of electromagnetic counterparts with gravitational-wave detection provides rich information about the merger events. Among the possible electromagnetic counterparts from the black hole-neutron merger, the emission powered by the decay of radioactive r-process nuclei, so called kilonova/macronova, is one of the best targets for follow-up observation. We derive fitting formulas for the mass and the velocity of ejecta from a generic black hole-neutron merger based on recently performed numerical relativity simulations. We combined these fitting formulas with a new semi-analytic model for a black hole-neutron kilonova/macronova lightcurve which reproduces the results of radiation-transfer simulations. Specifically, the semi-analytic model reproduces the result of each band mag...
Black liquor combustion validated recovery boiler modeling, five-year report
Energy Technology Data Exchange (ETDEWEB)
Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.
1996-08-01
The objective of this project was to develop a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The project originated in October 1990 and was scheduled to run for four years. At that time, there was considerable emphasis on developing accurate predictions of the physical carryover of macroscopic particles of partially burnt black liquor and smelt droplets out of the furnace, since this was seen as the main cause of boiler plugging. This placed a major emphasis on gas flow patterns within the furnace and on the mass loss rates and swelling and shrinking rates of burning black liquor drops. As work proceeded on developing the recovery boiler furnace model, it became apparent that some recovery boilers encounter serious plugging problems even when physical carryover was minimal. After the original four-year period was completed, the project was extended to address this issue. The objective of the extended project was to improve the utility of the models by including the black liquor chemistry relevant to air emissions predictions and aerosol formation, and by developing the knowledge base and computational tools to relate furnace model outputs to fouling and plugging of the convective sections of the boilers. The work done to date includes CFD model development and validation, acquisition of information on black liquor combustion fundamentals and development of improved burning models, char bed model development, and model application and simplification.
Making Clean Energy with a Kerr Black Hole: A Tokamak Model for Gamma-Ray Bursts
Li, Li-Xin
2000-11-01
In this paper we present a model for making clean energy with a Kerr black hole. Consider a Kerr black hole with a dense plasma torus spinning around it. A toroidal electric current flows on the surface of the torus, which generates a poloidal magnetic field outside the torus. On the surface of the torus the magnetic field is parallel to the surface. The closed magnetic field lines winding around the torus compress and confine the plasma in the torus, as in the case of tokamaks. Although it is unclear whether such a model is stable, we look into the consequences if the model is stable. If the magnetic field is strong enough, the baryonic contamination from the plasma in the torus is greatly suppressed by the magnetic confinement, and a clean magnetosphere of electron-positron pairs is built up around the black hole. Since there are no open magnetic field lines threading the torus and no accretion, the power of the torus is zero. If some magnetic field lines threading the black hole are open and connect with loads, clean energy can be extracted from the Kerr black hole by the Blandford-Znajek mechanism. The model may be relevant to gamma-ray bursts. The energy in the Poynting flux produced by the Blandford-Znajek mechanism is converted into the kinetic energy of the electron-positron pairs in the magnetosphere around the black hole, which generates two oppositely directed jets of electron-positron pairs with superhigh bulk Lorentz factors. The jets collide and interact with the interstellar medium, which may produce gamma-ray bursts and the afterglows.
DEFF Research Database (Denmark)
Langkjær, Michael Alexander
2012-01-01
Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as...
Blackman, Jonathan; Galley, Chad R; Szilagyi, Bela; Scheel, Mark A; Tiglio, Manuel; Hemberger, Daniel A
2015-01-01
Simulating a binary black hole coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. In this paper, we construct an accurate and fast-to-evaluate surrogate model for numerical relativity (NR) waveforms from non-spinning binary black hole coalescences with mass ratios from $1$ to $10$ and durations corresponding to about $15$ orbits before merger. Our surrogate, which is built using reduced order modeling techniques, is distinct from traditional modeling efforts. We find that the full multi-mode surrogate model agrees with waveforms generated by NR to within the numerical error of the NR code. In particular, we show that our modeling strategy produces surrogates which can correctly predict NR waveforms that were {\\em not} used for the surrogate's training. For all practical purposes, then, the surrogate waveform model is equivalent to the high-accuracy, large-scale simulation waveform but can be evaluated in a millisecond to a second dependin...
Adaptive-Wave Alternative for the Black-Scholes Option Pricing Model
Ivancevic, Vladimir G.
2009-01-01
A nonlinear wave alternative for the standard Black-Scholes option-pricing model is presented. The adaptive-wave model, representing 'controlled Brownian behavior' of financial markets, is formally defined by adaptive nonlinear Schr\\"odinger (NLS) equations, defining the option-pricing wave function in terms of the stock price and time. The model includes two parameters: volatility (playing the role of dispersion frequency coefficient), which can be either fixed or stochastic, and adaptive ma...
Modeling seed dispersal of black cherry, an invasive forest tree: how microsatellites may help?
Pairon, Marie; Jonard, Mathieu; Jacquemart, Anne-Laure
2006-01-01
We used empirical models and three dispersal functions (Weibull, lognormal and 2Dt) to model seed distributions derived from the black cherry (Prunus serotina Ehrh.) understorey of a pine-dominated stand. Two different approaches were used to disentangle the overlapping seed shadows: the traditional inverse modeling approach and the genetic approach that uses microsatellite markers to assign a dispersed seed to its maternal parent. The distinction was made between the seeds passively disperse...
Unveiling the nucleus of NGC 7172
Smajić, S.; Fischer, S.; Zuther, J.; Eckart, A.
2012-08-01
Aims: We present the results of near-infrared (NIR) H + K European Southern Observatory SINFONI integral field spectroscopy (IFS) of the Seyfert 2 galaxy NGC 7172. We investigate the central 800 pc, concentrating on excitation conditions, morphology, and stellar content. NGC 7172 was selected from a sample of the ten nearest Seyfert 2 galaxies from the Veron-Cetty & Veron catalogue. All objects were chosen as test cases for adaptive optics (AO) assisted observations that allow a detailed study (at high spatial and spectral resolution) of the nuclear and host environments. NGC 7172 has a prominent dustlane crossing the central galaxy region from east to west, which makes it an ideal candidate to investigate the effect of obscuration by strong galactic extinction on (active) galaxies and their classification. Methods: The NIR is less influenced by dust extinction than optical light and is sensitive to the mass-dominating stellar populations. SINFONI integral field spectroscopy combines NIR imaging and spectroscopy and provides us with the opportunity to analyze several emission and absorption lines to investigate the stellar populations and ionization mechanisms over the 4″ × 4″ field of view (FOV). Results: We present emission and absorption line measurements in the central 800 pc of NGC 7172. The detection of [Si vi] and broad Paα and Brγ components are clear signs of an accreting super-massive black hole hiding behind the prominent dustlane at visible wavelengths. Hot temperatures of about 1300 K are indicative of a dusty torus in the nuclear region. Narrow components of Paα and Brγ enable us to make an extinction measurement. Our measures of the molecular hydrogen lines, hydrogen recombination lines, and [Fe ii] indicate that the excitation of these lines is caused by an active galactic nucleus. The central region of the galactic disk is predominantly inhabited by gas, dust, and an old K-M type giant stellar population. The gaseous, molecular, and
Simple Entropic Derivation of a Generalized Black-Scholes Option Pricing Model
Directory of Open Access Journals (Sweden)
Michael J. Stutzer
2000-04-01
Full Text Available Abstract: A straightforward derivation of the celebrated Black-Scholes Option Pricing model is obtained by solution of a simple constrained minimization of relative entropy. The derivation leads to a natural generalization of it, which is consistent with some evidence from stock index option markets.
Simple Entropic Derivation of a Generalized Black-Scholes Option Pricing Model
Michael J. Stutzer
2000-01-01
Abstract: A straightforward derivation of the celebrated Black-Scholes Option Pricing model is obtained by solution of a simple constrained minimization of relative entropy. The derivation leads to a natural generalization of it, which is consistent with some evidence from stock index option markets.
Wavelet methods for Black-Scholes model of one and two assets
Al-Lawatia, M.
2012-07-01
A review of application of wavelet methods to Black-Scholes model of option pricing technology along wih some new results is presented. This paper is essentially based on interesting papers; Bouchouev and Isakov [8], Bouchouev, Isakov and Valadivia [9] and Shen and Strang [40].
A Model of Direct Contact Membrane Distillation of Black Currant Juice
DEFF Research Database (Denmark)
Jensen, Morten Busch; Christensen, Knud Villy; Andrésen, René;
2011-01-01
-side spacing of tubular-type unit." Turtuosity and porosity are characteristics of the membrane in use and have been estimated base don eksperimental studies on destillation of pure water. The fitted model shows a good fit to experimental data obtained by destillation of black currant juice....
Off The Beaten Path: Modeling the Dynamics of Supermassive Black Holes in Cosmological Simulations
Tremmel, Michael J.; Governato, Fabio; Volonteri, Marta; Quinn, Thomas R.
2015-01-01
Cosmological simulations are an essential tool to understand the co-evolution of supermassive black holes (SMBHs) and their host galaxies. However, the limited resolution of these simulations presents unique challenges to successfully modeling black hole dynamics. We present a novel, physically motivated method for improving the dynamics of black holes in cosmological simulations, by accounting for the unresolved dynamical friction that SMBHs feel from stars and dark matter. We show how this approach, which naturally scales with resolution, is a major step forward compared to more commonly used 'advection' models that often assume SMBHs sink very rapidly toward the center of their host galaxies. Here, we demonstrate that our method is able to prevent numerical heating of SMBHs while allowing for realistic dynamics.Our implementation will allow us to more realistically model SMBH dynamics, accretion, and mergers in cosmological simulations, giving us the ability to better understand how SMBHs grow with their host galaxies. This also provides an opportunity for more detailed studies of SMBHs in dwarf galaxies, which can give crucial insight into constraining black hole seed formation models.
A model for early diagenetic processes in sediments of the continental shelf of the Black Sea
Wijsman, J.W.M.; Herman, P.M.J.; Middelburg, J.J.; Soetaert, K.E.R.
2002-01-01
A numerical model for early diagenetic processes in the sediments of the north-western continental shelf of the Black Sea is presented. The north-western shelf area is influenced by nutrient, organic matter and reactive iron inputs from major rivers such as the Danube, Dnieper and Dniester. Low oxyg
Comment on Self-Consistent Model of Black Hole Formation and Evaporation
Ho, Pei-Ming
2015-01-01
In an earlier work, Kawai et al proposed a model of black-hole formation and evaporation, in which the geometry of a collapsing shell of null dust is studied, including consistently the back reaction of its Hawking radiation. In this note, we illuminate the implications of their work, focusing on the resolution of the information loss paradox and the problem of the firewall.
A Research Brief: A Novel Characteristic of Role Model Choice by Black Male College Students
Bennett, B. J.; Davis, R.; Harris, A.; Brown, K.; Wood, P.; Jones, D. R.; Spencer, S.; Nelson, L.; Brown, J.; Waddell, T.; Jones, C. B.
2004-01-01
The purpose of the present research brief is to report a novel characteristic of role model choice that may be unreported in the literature for black males and to assess this finding in relation to perceived attractiveness of self and a member of the opposite sex. The study found that the proportion of males choosing themselves as their own role…
Bohr's Semiclassical Model of the Black Hole Thermodynamics
Pankovic, V.; Predojevic, M.; Grujic, P.
2008-06-01
ekenstein, J. D. 1973, Phys. Rev. D, 7, 2333 Bekenstein, J. D. 1994, gr-qc/9409015v2 Bekenstein, J. D. 1998, gr-qc/9808028v3 Frasca, M. 2005, hep-th/0411245v4 Grujic, P. V. 1993, Bull. Astron. Belgrade, 147, 15 Hawking, S. W. 1975, Comm. Math. Phys., 43, 199 Hawking, S. W. 1979, in "General Relativity, an Einstein Centenary Survey," Eds. S. W. Hawking and W. Israel (Cambridge: Cambridge University Press) Nagatani, Y. 2007, Progr. Theor. Phys. Suppl., 164, 54 Nicolai,H., Peeters, K., & Zamaklar, M. 2005, Class. Quantum Grav., 22, R193 Norcliffe A. 1975, in "Case Studies in Atomic Physics - Vol. 4," Eds. E. W. McDaniel and M. R. McDowell (Amsterdam: North-Holland), 46 Page, D. N. 2004, hep-th/0409024 Pavon, D. 2007, J. Phys. A, 40, 6865 Proline, B. 2006, hep-th/0607227 Ram, B. 2000, Phys. Lett. A, 265, 1 Ram, B., Ram, A, Ram, N. 2005, The Quantum Black Hole, gr-qc/0504030 Samuel, J., & Chowdhury, S. R. 2007, Class. Quantum Grav., 24, F47 Strominger, D. N., Vafa, C. 1996, Phys. Lett. B, 339, 99 Wald, R. M. 1997, gr-qc/9702022 Wald, R. M. 1999, gr-qc/9912119
A refined sub-grid model for black hole accretion and AGN feedback in large cosmological simulations
Bachmann, Lisa K; Hirschmann, Michaela; Prieto, M Almudena; Remus, Rhea-Silvia
2014-01-01
In large scale cosmological hydrodynamic simulations simplified sub-grid models for gas accretion onto black holes and AGN feedback are commonly used. Such models typically depend on various free parameters, which are not well constrained. We present a new advanced model containing a more detailed description of AGN feedback, where those parameters reflect the results of recent observations. The model takes the dependency of these parameters on the black hole properties into account and describes a continuous transition between the feedback processes acting in the so-called radio-mode and quasar-mode. In addition, we implement a more detailed description of the accretion of gas onto black holes by distinguishing between hot and cold gas accretion. Our new implementations prevent black holes from gaining too much mass, particularly at low redshifts so that our simulations are now very successful in reproducing the observed present-day black hole mass function. Our new model also suppresses star formation in ma...
Modelling non-paradoxical loss of information in black hole evaporation
Modak, Sujoy K
2016-01-01
We give general overview of a novel approach, recently developed by us, to address the issue black hole information paradox. This alternative viewpoint is based on theories involving modifications of standard quantum theory, known as "spontaneous dynamical state reduction" or "wave-function collapse models" which were historically developed to overcome the notorious foundational problems of quantum mechanics known as the "measurement problem". We show that these proposals, when appropriately adapted and refined for this context, provide a self-consistent picture where loss of information in the evaporation of black holes is no longer paradoxical.
Hawking evaporation of cosmogenic black holes in TeV-gravity models
International Nuclear Information System (INIS)
We study the properties of black holes of mass 104–1011 GeV in models with the fundamental scale of gravity at the TeV. These black holes could be produced in the collision of a ultrahigh energy cosmic ray with a dark matter particle in our galactic halo or with another cosmic ray. We show that QCD bremsstrahlung and pair production processes are unable to thermalize the particles exiting the black hole, so a chromosphere is never formed during Hawking evaporation. We evaluate with HERWIG the spectrum of stable four-dimensional particles emitted during the Schwarzschild phase and find that in all cases it is peaked at energies around 0.2 GeV, with an approximate 43% of neutrinos, 28% of photons, 16% of electrons and 13% of protons. Bulk gravitons are peaked at higher energies; they account for 0.4% of the particles (16% of the total energy) emitted by the most massive black holes in n = 6 extra dimensions or just the 0.02% of the particles (1.4% of the energy) emitted by a 10 TeV black hole for n = 2
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation
Brádler, Kamil; Adami, Christoph
2016-03-01
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum.
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation.
Brádler, Kamil; Adami, Christoph
2016-03-11
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum. PMID:27015471
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation.
Brádler, Kamil; Adami, Christoph
2016-03-11
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum.
Dynamical nucleus-nucleus potential at short distances
Jiang, Yongying; Wang, Ning; Li, Zhuxia; Scheid, Werner
2010-01-01
The dynamical nucleus-nucleus potentials for fusion reactions 40Ca+40Ca, 48Ca+208Pb and 126Sn+130Te are studied with the improved quantum molecular dynamics (ImQMD) model together with the extended Thomas-Fermi approximation for the kinetic energies of nuclei. The obtained fusion barrier for 40Ca+40Ca is in good agreement with the extracted fusion barrier from the measured fusion excitation function, and the depth of the fusion pockets are close to the results of time-dependent Hartree-Fock c...
Modeling of Temperature Conditions Between Temperature Artifact and Black Test Corner
Beges, G.
2011-12-01
The case study in this article is temperature condition modeling between a temperature artifact and a black test corner measuring instrument. The black test corner is an instrument which consists of two wooden walls and a floor, with build-in thermocouples fixed on the back side of the copper disks. The front of the disk is flush with the surface of the board. The black test corner is used for measuring how the temperature of a household appliance is influencing the surroundings in the real environment, e.g., in the kitchen, the living room, etc. The temperature artifact as presented in this article is a specially developed heating plate which is very stable and can be set to different temperatures. Technical standards for conformity assessment usually describe only what should be measured, in some cases also how accurate the measurement should be, but not what kind of measuring instrument should be used. Therefore, it sometimes happens that measurements are performed with improper equipment or in an improper way. For the same level of appliance conformance testing, laboratories shall use the same testing procedures and comparable measuring instruments. This article deals with the analysis of influencing parameters when measuring the temperature rise using the black test corner. Modeling of temperature conditions between a temperature artifact and a black test corner, using commercial modeling software, was performed to find out whether this modeling can be used for detailed evaluation of all possible influencing parameters of the mentioned testing procedure. A scheme and a list of influencing parameters that has to be modeled in the following research is prepared to arrange an optimal experiment.
Institute of Scientific and Technical Information of China (English)
Hong Gao; Bangyu Ju; Guohua Jiang
2008-01-01
BACKGROUND: The effect of acupuncture treatment on peripheral facial nerve injury is generally accepted. However, the mechanisms of action remain poorly understood. OBJECTIVE: To validate the effect of acupoint electro-stimulation on brain-derived neurotrophic factor (BDNF) mRNA expression in the facial nucleus of rabbits with facial nerve injury, with the hypothesis that acupuncture treatment efficacy is related to BDNE DESIGN, TIME AND SETTING: Peripheral facial nerve injury, in situ hybridization, and randomized, controlled, animal trial. The experiment was performed at the Laboratory of Anatomy, Heilongjiang University of Chinese Medicine from March to September 2005. MATERIALS: A total of 120 healthy, adult, Japanese rabbits, with an equal number of males and females were selected. Models of peripheral facial nerve injury were established using the facial nerve pressing method. METHODS: The rabbits were randomly divided into five groups (n = 24): sham operation, an incision to the left facial skin, followed by suture; model, no treatment following facial nerve model establishment; western medicine, 10 mg vitamin B1, 50 μg vitamin B12, and dexamethasone (2 mg/d, reduced to half every 7 days) intramuscular injection starting with the first day following lesion, once per day; traditional acupuncture, acupuncture at Yifeng, Quanliao, Dicang, Jiache, Sibai, and Yangbai acupoints using a acupuncture needle with needle twirling every 10 minutes, followed by needle retention for 30 minutes, for successive 5 days; electroacupuncture, similar to the traditional acupuncture group, the Yifeng (negative electrode), Jiache (positive electrode), Dicang (negative electrode), and Sibai (positive electrode) points were connected to an universal pulse electro-therapeutic apparatus for 30 minutes per day, with disperse-dense waves for successive 5 days, and resting for 2 days. MAIN OUTCOME MEASURES: Left hemisphere brain stem tissues were harvested on post-operative days 7, 14
Di Paolo, Carolina; Gandhi, Nilima; Bhavsar, Satyendra P; Van den Heuvel-Greve, Martine; Koelmans, Albert A
2010-10-01
Bioavailability and bioaccumulation of polybrominated diphenylethers (PBDEs) are affected by adsorption on black carbon (BC) and metabolism in biota, respectively. Recent studies have addressed these two processes separately, illustrating their importance in assessing contaminant dynamics. In order to properly examine biomagnification of polychlorinated biphenyls (PCBs) and PBDEs in an estuarine food-web, here we set up a black carbon inclusive multichemical model. A dual domain sorption model, which accounted for sorption to organic matter (OM) and black carbon (BC), was used to estimate aqueous phase concentrations from the measured chemical concentrations in suspended solids. We adapted a previously published multichemical model that tracks the movement of a parent compound and its metabolites in each organism and within its food web. First, the model was calibrated for seven PCB congeners assuming negligible metabolism. Subsequently, PBDE biomagnification was modeled, including biotransformation and bioformation of PBDE congeners, keeping the other model parameters the same. The integrated model was capable of predicting trophic magnification factors (TMF) within error limits. PBDE metabolic half-lives ranged 21-415 days and agreed to literature data. The results showed importance of including BC as an adsorbing phase, and biotransformation and bioformation of PBDEs for a proper assessment of their dynamics in aquatic systems. PMID:20828201
A magnetic model for low/hard state of black hole binaries
Ye, Yong-Chun; Huang, Chang-Yin; Cao, Xiao-Feng
2015-01-01
A magnetic model for low/hard state (LHS) of black hole X-ray binaries (BHXBs),H1743-322 and GX 339-4, is proposed based on the transportation of magnetic field from a companion into an accretion disk around a black hole (BH). This model consists of a truncated thin disk with an inner advection-dominated accretion flow (ADAF). The spectral profiles of the sources are fitted in agreement with the data observed at four different dates corresponding to the rising phase of the LHS. In addition, the association of the LHS with quasi-steady jet is modelled based on transportation of magnetic field, where the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes are invoked to drive the jets from BH and inner ADAF. It turns out that the steep radio/X-ray correlations observed in H1743-322 and GX 339-4 can be interpreted based on our model.
The mass function of black holes 1
Natarajan, Priyamvada; Volonteri, Marta
2012-05-01
In this paper, we compare the observationally derived black hole mass function (BHMF) of luminous (>1045-1046 erg s-1) broad-line quasars (BLQSOs) at 1 rate as well as rates drawn from the distribution derived by Merloni & Heinz. Four model snapshots at z= 1.25, 2, 3.25 and 4.25 are compared with the SDSS-derived BHMFs of BLQSOs. We find that the light seed models fall short of reproducing the observationally derived mass function of BLQSOs at MBH > 109 M⊙ throughout the redshift range; the massive seed models with a fixed accretion rate of 0.3 Edd, or with accretion rates drawn from the Merloni & Heinz distribution provide the best fit to the current observational data at z > 2, although they overestimate the high-mass end of the mass function at lower redshifts. At low redshifts, a drastic drop in the accretion rate is observed and this is explained as arising due to the diminished gas supply available due to consumption by star formation or changes in the geometry of the inner feeding regions. Therefore, the overestimate at the high-mass end of the black hole mass function for the massive seed models can be easily modified, as the accretion rate is likely significantly lower at these epochs than what we assume. For the Merloni & Heinz model, examining the Eddington ratio distributions fEdd, we find that they are almost uniformly sampled from fEdd= 10-2 to 1 at z≃ 1, while at high redshift, current observations suggest accretion rates close to Eddington, if not mildly super-Eddington, at least for these extremely luminous quasars. Our key findings are that the duty cycle of super-massive black holes powering BLQSOs increases with increasing redshift for all models and models with Population III remnants as black hole seeds are unable to fit the observationally derived BHMFs for BLQSOs, lending strong support for the massive seeding model.
A model for early diagenetic processes in sediments of the continental shelf of the Black Sea
Wijsman, J.W.M.; P. M. J. Herman; Middelburg, J. J.; K. Soetaert
2001-01-01
A numerical model for early diagenetic processes in the sediments of the north-western continental shelf of the Black Sea is presented. The north-western shelf area is influenced by nutrient, organic matter and reactive iron inputs from major rivers such as the Danube, Dnieper and Dniester. Low oxygen concentrations in the bottom water and high carbon deposition rates have resulted in a dominance of anoxic mineralization processes including manganese, iron and sulphate reduction. The model in...
International Nuclear Information System (INIS)
Some new aspects on the multifragmentation processes in nucleus-nucleus and nucleon-nucleus collisions at high energies are discussed in this work. Experimental data obtained in international collaborations (for example, MULTI Collaboration with KEK Tsukuba (Japan) and SKM 200 Collaboration with JINR Dubna (Russia)) are used to discuss new mechanisms in the target nucleus fragmentation. Correlations with stopping power, participant region size and energy density are included. Comparisons of the experimental results with the predictions of a phenomenological geometric model of intermediate mass fragment multiplicity, caloric curves and angular distributions are also presented. These results are used for global description of the multifragmentation processes in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies. The size of the participant region and the average intermediate mass fragments multiplicity are taken into consideration using the free space probability. A few correlations between the deposited energy in the participant region and stability state of the intermediate mass fragments are presented in this work. The importance of the collision geometry in the multifragmentation processes is stressed. The results suggest different time moments for the incident nucleus fragmentation and for the target nucleus fragmentation. The associated entropies are distinct. (authors)
Alsing, Paul M
2014-01-01
In this paper, we extend the investigation of Adami and Ver Steeg [Class. Quantum Grav. \\textbf{31}, 075015 (2014)] to treat the process of black hole particle emission as an effective parametric down conversion (PDC) with a depleted (vs. un-depleted) pump. We investigate both the short time (non-depleted pump regime) and long time (depleted pump regime) and its impact on the Holevo channel capacity for communicating information from the far past to the far future in the presence of Hawking radiation. The new feature introduced in this paper is the coupling of the emitted modes through the black hole `source pump' which can be depleted. Within our analogous quantum optical model we examine the entanglement between two emitted particle/anti-particle and anti-particle/particle pairs coupled via the black hole (BH) depleted `pump.' We also investigate the 'Page time' for our model which refers to the conventionally held belief that the information in the BH radiation becomes significant after the black hole has ...
Black hole mass and binary model for BL Lac object OJ 287
Liu, F K; Wu, Xue-Bing
2002-01-01
Recent intensive observations of the BL Lac object OJ 287 raise a lot of questions on the models of binary black holes, processing jets, rotating helical jets and thermal instability of slim accretion disks. After carefully analyzing their radio flux and polarization data, Valtaoja et al. (\\cite{valtaoja00}) propose a new binary model. Based on the black hole mass of $4 \\times 10^8 {\\rm M_\\odot}$ estimated with the tight correlations of the black hole masses and the bulge luminosity or central velocity dispersion of host galaxies, we computed the physical parameters of the new binary scenario. The impact of the secondary on the accretion disk around the primary black hole causes strong shocks propagating inwards and outwards, whose arrival at the jet roots is identified with the rapid increase of optical polarization and the large change of polarization angle at about 0.30 yr after the first main optical flare. An increase of optical polarization, a large rotation of positional angle and a small synchrotron f...
Adaptation of warrant price with Black Scholes model and historical volatility
Aziz, Khairu Azlan Abd; Idris, Mohd Fazril Izhar Mohd; Saian, Rizauddin; Daud, Wan Suhana Wan
2015-05-01
This project discusses about pricing warrant in Malaysia. The Black Scholes model with non-dividend approach and linear interpolation technique was applied in pricing the call warrant. Three call warrants that are listed in Bursa Malaysia were selected randomly from UiTM's datastream. The finding claims that the volatility for each call warrants are different to each other. We have used the historical volatility which will describes the price movement by which an underlying share is expected to fluctuate within a period. The Black Scholes model price that was obtained by the model will be compared with the actual market price. Mispricing the call warrants will contribute to under or over valuation price. Other variables like interest rate, time to maturity date, exercise price and underlying stock price are involves in pricing call warrants as well as measuring the moneyness of call warrants.
Modeling Black Sea circulation with high resolution in the coastal zone
Zalesnyi, V. B.; Gusev, A. V.; Agoshkov, V. I.
2016-05-01
We present a numerical model of Black Sea circulation based on primitive equations with improved spatial resolution in the coastal zone. The model equations are formulated in a two-pole orthogonal coordinate system with arbitrary locations of the poles and a vertical σ coordinate. Increased horizontal resolution is gained by displacing the pole into the vicinity of the separated subdomain. The problem is solved over a grid with a variable step. The northern coordinate pole is displaced to the vicinity of Gelendzhik; the grid step varies from 150 m in the coastal zone to 4.6 km in the main basin. We simulated the fields of currents, sea level, temperature, and salinity under the given atmospheric forcing in 2007. The model is capable of reproducing the large-scale Black Sea circulation and submesoscale variations in the coastal currents.
A model for 3:2 HFQPO pairs in black hole binaries based on cosmic battery
Huang, Chang-Yin; Wang, Ding-Xiong; Li, Yang
2016-01-01
A model for 3:2 high-frequency quasi-periodic oscillations (HFQPOs) with 3:2 pairs observed in four black hole X-ray binaries (BHXBs) is proposed by invoking the epicyclic resonances with the magnetic connection (MC) between a spinning black hole (BH) with a relativistic accretion disc. It turns out that the MC can be worked out due to Poynting-Robertson cosmic battery (PRCB), and the 3:2 HFQPO pairs associated with the steep power-law states can be fitted in this model. Furthermore, the severe damping problem in the epicyclic resonance model can be overcome by transferring energy from the BH to the inner disc via the MC process for emitting X-rays with sufficient amplitude and coherence to produce the HFQPOs. In addition, we discuss the important role of the magnetic field in state transition of BHXBs.
Study of the spectral and the temporal properties of few black hole candidates with TCAF model
Mondal, Santanu; Debnath, Dipak; Chakrabarti, Sandip Kumar
We study spectral and temporal properties of outbursting black hole candidates (BHCs) using Two Component Advective Flow (TCAF) model in XSPEC as a local additive table model. Evolution of spectral and temporal properties of BHCs can easily be explained with spectral analysis using TCAF. From TCAF model fit of black hole spectra one can extract two types of flow rates (Keplerian and sub-Keplerian rates) and shock parameters (location and strength), which give new insight into the problem of accretion dynamics. Depending upon accretion rate ratio (ARR) and nature of QPOs (if present) we can classify total outburst phases of transient BHCs in different spectral states. This classification qualitatively match with the classifications based on spectral properties alone. However, in our process, use the physical quantities, such as accretion rates gave a complete, meaning of what exactly happens in a state transition. We also compare TCAF model fitted spectral results with combined disk black body and power-law model fitted results, which almost matches. In our study, evolution of quasi periodic oscillations (QPOs) also explained from the movement of shock location. It is also clear from the analysis that the rising and declining phases may not retrace the same path always and form a hysteresis loop.
CCN activation of pure and coated carbon black particles.
Dusek, U; Reischl, G P; Hitzenberger, R
2006-02-15
The CCN (cloud condensation nucleus) activation of pure and coated carbon black particles was investigated using the University of Vienna cloud condensation nuclei counter (Giebl, H.; Berner, A.; Reischl, G.; Puxbaum, H.; Kasper-Giebl, A.; Hitzenberger, R. J. Aerosol Sci. 2002, 33, 1623-1634). The particles were produced by nebulizing an aqueous suspension of carbon black in a Collison atomizer. The activation of pure carbon black particles was found to require higher supersaturations than predicted by calculations representing the particles as insoluble, wettable spheres with mobility equivalent diameter. To test whether this effect is an artifact due to heating of the light-absorbing carbon black particles in the laser beam, experiments at different laser powers were conducted. No systematic dependence of the activation of pure carbon black particles on laser power was observed. The observations could be modeled using spherical particles and an effective contact angle of 4-6 degrees of water at their surface. The addition of a small amount of NaCl to the carbon black particles (by adding 5% by mass NaCl to the carbon black suspension) greatly enhanced their CCN efficiency. The measured CCN efficiencies were consistent with Kohler theory for particles consisting of insoluble and hygroscopic material. However, coating the carbon black particles with hexadecanol (a typical film-forming compound with one hydrophobic and one hydrophilic end) efficiently suppressed the CCN activation of the carbon black particles.
Black carbon fractal morphology and short-wave radiative impact: a modelling study
Directory of Open Access Journals (Sweden)
M. Kahnert
2011-08-01
Full Text Available We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of differences in the optical cross sections and asymmetry parameters. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably
To test dual supermassive black hole model for broad line AGN with double-peaked narrow [OIII] lines
XueGuang, Zhang
2016-01-01
In this manuscript, we proposed an interesting method to test the dual supermassive black hole model for AGN with double-peaked narrow \\oiii lines (double-peaked narrow emitters), through their broad optical Balmer line properties. Under the dual supermassive black hole model for double-peaked narrow emitters, we could expect statistically smaller virial black hole masses estimated by observed broad Balmer line properties than true black hole masses (total masses of central two black holes). Then, we compare the virial black hole masses between a sample of 37 double-peaked narrow emitters with broad Balmer lines and samples of SDSS selected normal broad line AGN with single-peaked \\oiii lines. However, we can find clearly statistically larger calculated virial black hole masses for the 37 broad line AGN with double-peaked \\oiii lines than for samples of normal broad line AGN. Therefore, we give our conclusion that the dual supermassive black hole model is probably not statistically preferred to the double-pea...
Multi-asset Black-Scholes model as a variable second class constrained dynamical system
Bustamante, M.; Contreras, M.
2016-09-01
In this paper, we study the multi-asset Black-Scholes model from a structural point of view. For this, we interpret the multi-asset Black-Scholes equation as a multidimensional Schrödinger one particle equation. The analysis of the classical Hamiltonian and Lagrangian mechanics associated with this quantum model implies that, in this system, the canonical momentums cannot always be written in terms of the velocities. This feature is a typical characteristic of the constrained system that appears in the high-energy physics. To study this model in the proper form, one must apply Dirac's method for constrained systems. The results of the Dirac's analysis indicate that in the correlation parameters space of the multi-assets model, there exists a surface (called the Kummer surface ΣK, where the determinant of the correlation matrix is null) on which the constraint number can vary. We study in detail the cases with N = 2 and N = 3 assets. For these cases, we calculate the propagator of the multi-asset Black-Scholes equation and show that inside the Kummer ΣK surface the propagator is well defined, but outside ΣK the propagator diverges and the option price is not well defined. On ΣK the propagator is obtained as a constrained path integral and their form depends on which region of the Kummer surface the correlation parameters lie. Thus, the multi-asset Black-Scholes model is an example of a variable constrained dynamical system, and it is a new and beautiful property that had not been previously observed.
Energy Technology Data Exchange (ETDEWEB)
Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.
1998-08-01
This project was initiated in October 1990, with the objective of developing and validating a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The key tasks to be accomplished were as follows: (1) Complete the development of enhanced furnace models that have the capability to accurately predict carryover, emissions behavior, dust concentrations, gas temperatures, and wall heat fluxes. (2) Validate the enhanced furnace models, so that users can have confidence in the predicted results. (3) Obtain fundamental information on aerosol formation, deposition, and hardening so as to develop the knowledge base needed to relate furnace model outputs to plugging and fouling in the convective sections of the boiler. (4) Facilitate the transfer of codes, black liquid submodels, and fundamental knowledge to the US kraft pulp industry. Volume 4 contains the following appendix sections: Radiative heat transfer properties for black liquor combustion -- Facilities and techniques and Spectral absorbance and emittance data; and Radiate heat transfer determination of the optical constants of ash samples from kraft recovery boilers -- Calculation procedure; Computation program; Density determination; Particle diameter determination; Optical constant data; and Uncertainty analysis.
Modelling black holes with angular momentum in loop quantum gravity
Frodden, Ernesto; Perez, Alejandro; Pranzetti, Daniele; Röken, Christian
2014-12-01
We construct a connection formulation of Kerr isolated horizons. As in the non-rotating case, the model is based on a Chern-Simons theory describing the degrees of freedom on the horizon. The presence of a non-vanishing angular momentum modifies the admissibility conditions for spin network states. Physical states of the system are in correspondence with open intertwiners with total spin matching the angular momentum of the spacetime.
Directory of Open Access Journals (Sweden)
A A Eicher
2012-09-01
Full Text Available Magnetic Resonance Imaging provides a non-invasive means to study the neural correlates of Fetal Alcohol Spectrum Disorder (FASD - the most common form of preventable mental retardation worldwide. One approach aims to detect brain abnormalities through an assessment of volume and shape of two sub-cortical structures, the caudate nucleus and hippocampus. We present a method for automatically segmenting these structures from high-resolution MR images captured as part of an ongoing study into the neural correlates of FASD. Our method incorporates an Active Shape Model, which is used to learn shape variation from manually segmented training data. A modified discrete Geometrically Deformable Model is used to generate point correspondence between training models. An ASM is then created from the landmark points. Experiments were conducted on the image search phase of ASM segmentation, in order to find the technique best suited to segmentation of the hippocampus and caudate nucleus. Various popular image search techniques were tested, including an edge detection method and a method based on grey profile Mahalanobis distance measurement. A novel heuristic image search method was also developed and tested. This heuristic method improves image segmentation by taking advantage of characteristics specific to the target data, such as a relatively homogeneous tissue colour in target structures. Results show that ASMs that use the heuristic image search technique produce the most accurate segmentations. An ASM constructed using this technique will enable researchers to quickly, reliably, and automatically segment test data for use in the FASD study.
Robust option replication for a Black-Scholes model extended with nondeterministic trends
Directory of Open Access Journals (Sweden)
John G. M. Schoenmakers
1999-01-01
Full Text Available Statistical analysis on various stocks reveals long range dependence behavior of the stock prices that is not consistent with the classical Black and Scholes model. This memory or nondeterministic trend behavior is often seen as a reflection of market sentiments and causes that the historical volatility estimator becomes unreliable in practice. We propose an extension of the Black and Scholes model by adding a term to the original Wiener term involving a smoother process which accounts for these effects. The problem of arbitrage will be discussed. Using a generalized stochastic integration theory [8], we show that it is possible to construct a self financing replicating portfolio for a European option without any further knowledge of the extension and that, as a consequence, the classical concept of volatility needs to be re-interpreted.
:,; 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...
Relativistic Accretion Disk Models of High State Black Hole X-ray Binary Spectra
Davis, S W; Hubeny, I; Turner, N J; Davis, Shane W.; Blaes, Omer M.; Hubeny, Ivan; Turner, Neal J.
2004-01-01
We present calculations of non-LTE, relativistic accretion disk models applicable to the high/soft state of black hole X-ray binaries. We include the effects of thermal Comptonization and bound-free and free-free opacities of all abundant ion species. We present spectra calculated for a variety of accretion rates, black hole spin parameters, disk inclinations, and stress prescriptions. We also consider nonzero inner torques on the disk, and explore different vertical dissipation profiles, including some which are motivated by recent radiation MHD simulations of magnetorotational turbulence. Bound-free metal opacity generally produces significantly less spectral hardening than previous models which only considered Compton scattering and free-free opacity. It also tends to keep the effective photosphere near the surface, resulting in spectra which are remarkably independent of the stress prescription and vertical dissipation profile, provided little dissipation occurs above the effective photosphere. We provide...
Rahman, M A; Haque, S
2003-01-01
Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. sup 9 Be, sup 1 sup 6 O, sup 2 sup 0 Ne and sup 3 sup 2 S heavy-ion beams elastic scattering from sup 2 sup 8 Si, sup 2 sup 4 Mg and sup 4 sup 0 Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-paramet...
International Nuclear Information System (INIS)
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
Observational Evidence for Black Holes
Narayan, Ramesh; McClintock, Jeffrey E.
2013-01-01
Astronomers have discovered two populations of black holes: (i) stellar-mass black holes with masses in the range 5 to 30 solar masses, millions of which are present in each galaxy in the universe, and (ii) supermassive black holes with masses in the range 10^6 to 10^{10} solar masses, one each in the nucleus of every galaxy. There is strong circumstantial evidence that all these objects are true black holes with event horizons. The measured masses of supermassive black hole are strongly corr...
Dons, Evi; Van Poppel, Martine; Kochan, Bruno; Wets, Geert; Int Panis, Luc
2013-01-01
Land use regression (LUR) modeling is a statistical technique used to determine exposure to air pollutants in epidemiological studies. Time-activity diaries can be combined with LUR models, enabling detailed exposure estimation and limiting exposure misclassification, both in shorter and longer time lags. In this study, the traffic related air pollutant black carbon was measured with mu-aethalometers on a 5-mm time base at 63 locations in Flanders, Belgium. The measurements show that hourly c...
On the Black-Scholes European Option Pricing Model Robustness and Generality
Takada, Hellinton Hatsuo; de Oliveira Siqueira, José
2008-11-01
The common presentation of the widely known and accepted Black-Scholes European option pricing model explicitly imposes some restrictions such as the geometric Brownian motion assumption for the underlying stock price. In this paper, these usual restrictions are relaxed using maximum entropy principle of information theory, Pearson's distribution system, market frictionless and risk-neutrality theories to the calculation of a unique risk-neutral probability measure calibrated with market parameters.
Models of Kilonova/Macronova Emission from Black Hole–Neutron Star Mergers
Kawaguchi, Kyohei; Kyutoku, Koutarou; Shibata, Masaru; Tanaka, Masaomi
2016-07-01
Black hole–neutron star (BH–NS) mergers are among the most promising gravitational-wave sources for ground-based detectors, and gravitational waves from BH–NS mergers are expected to be detected in the next few years. The simultaneous detection of electromagnetic counterparts with gravitational waves would provide rich information about merger events. Among the possible electromagnetic counterparts from BH–NS mergers is the so-called kilonova/macronova, emission powered by the decay of radioactive r-process nuclei, which is one of the best targets for follow-up observations. We derive fitting formulas for the mass and the velocity of ejecta from a generic BH–NS merger based on recently performed numerical-relativity simulations. We combine these fitting formulas with a new semi-analytic model for a BH–NS kilonova/macronova lightcurve, which reproduces the results of radiation-transfer simulations. Specifically, the semi-analytic model reproduces the results of each band magnitude obtained by the previous radiation-transfer simulations within ∼1 mag. By using this semi-analytic model we found that, at 400 Mpc, the kilonova/macronova is as bright as 22–24 mag for cases with a small chirp mass and a high black hole spin, and >28 mag for a large chirp mass and a low black hole spin. We also apply our model to GRB 130603B as an illustration, and show that a BH–NS merger with a rapidly spinning black hole and a large neutron star radius is favored.
Elisha Townshend; Bharat Pokharel; Art Groot; Doug Pitt; DECH, JEFFERY P.
2015-01-01
Effective planning to optimize the forest value chain requires accurate and detailed information about the resource; however, estimates of the distribution of fibre properties on the landscape are largely unavailable prior to harvest. Our objective was to fit a model of the tree-level average fibre length related to ecosite classification and other forest inventory variables depicted at the landscape scale. A series of black spruce increment cores were collected at breast height from trees in...
MODELING BLACK-WHITE PRETERM BIRTH DISPARITY: ECOLOGIC AND MULTILEVEL MODELS
INTRODUCTION. The disparity between black and white women's adverse birth outcomes has been subject to much investigation, yet the factors underlying its persistence remain elusive, which has encouraged research on neighborhood-level influences. This work considers two main que...
Factors associated with leisure time physical inactivity in black individuals: hierarchical model
Directory of Open Access Journals (Sweden)
Francisco José Gondim Pitanga
2014-09-01
Full Text Available Background. A number of studies have shown that the black population exhibits higher levels of leisure-time physical inactivity (LTPI, but few have investigated the factors associated with this behavior. Objective. The aim of this study was to analyze associated factors and the explanatory model proposed for LTPI in black adults. Methods. The design was cross-sectional with a sample of 2,305 adults from 20–96 years of age, 902 (39.1% men, living in the city of Salvador, Brazil. LTPI was analyzed using the International Physical Activity Questionnaire (IPAQ. A hierarchical model was built with the possible factors associated with LTPI, distributed in distal (age and sex, intermediate 1 (socioeconomic status, educational level and marital status, intermediate 2 (perception of safety/violence in the neighborhood, racial discrimination in private settings and physical activity at work and proximal blocks (smoking and participation in Carnival block rehearsals. We estimated crude and adjusted odds ratio (OR using logistic regression. Results. The variables inversely associated with LTPI were male gender, socioeconomic status and secondary/university education, although the proposed model explains only 4.2% of LTPI. Conclusions. We conclude that male gender, higher education and socioeconomic status can reduce LTPI in black adults.
DEFF Research Database (Denmark)
Mashayekhi, Sima; Hugger, Jens
2015-01-01
Several nonlinear Black-Scholes models have been proposed to take transaction cost, large investor performance and illiquid markets into account. One of the most comprehensive models introduced by Barles and Soner in [4] considers transaction cost in the hedging strategy and risk from an illiquid...... market. In this paper, we compare several finite difference methods for the solution of this model with respect to precision and order of convergence within a computationally feasible domain allowing at most 200 space steps and 10000 time steps. We conclude that standard explicit Euler comes out...
Calabi-Yau Black Holes and (0,4) Sigma Models
Minasian, Ruben; Moore, Gregory; Tsimpis, Dimitrios
When an M-theory fivebrane wraps a holomorphic surface ? in a Calabi-Yau 3-fold X the low energy dynamics is that of a black string in 5 dimensional ? =1 supergravity. The infrared dynamics on the string worldsheet is an ? = (0,4) 2D conformal field theory. Assuming the 2D CFT can be described as a nonlinear sigma model, we describe the target space geometry of this model in terms of the data of X and ?. Variations of weight two Hodge structures enter the construction of the model in an interesting way.
Black-Scholes期权定价模型修正%The modification of Black-Scholes option pricing model
Institute of Scientific and Technical Information of China (English)
李晓雷
2007-01-01
Black-Scholes模型成功地解决了在有效市场下的期权定价问题,但它是在一定的假设条件下建立的.然而在实际的交易中,投资者通常会在得到一定的股票红利的同时也将面临着不容忽视的交易成本.本文在Black-Scholes模型的基础上,对界定了交易成本并考虑红利支付的情况下的期权定价的模型进行研究,从而使Black-Scholes模型更符合市场实际.
Two-phase model for Black Hole feeding and feedback
Nayakshin, Sergei
2013-01-01
We study effects of AGN feedback outflows on multi-phase inter stellar medium (ISM) of the host galaxy. We argue that SMBH growth is dominated by accretion of dense cold clumps and filaments. AGN feedback outflows overtake the cold medium, compress it, and trigger a powerful starburst -- a positive AGN feedback. This predicts a statistical correlation between AGN luminosity and star formation rate at high luminosities. Most of the outflow's kinetic energy escapes from the bulge via low density voids. The cold phase is pushed outward only by the ram pressure (momentum) of the outflow. The combination of the negative and positive forms of AGN feedback leads to an $M-\\sigma$ relation similar to the result of King (2003). Due to porosity of cold ISM in the bulge, SMBH influence on the low density medium of the host galaxy is significant even for SMBH well below the $M-\\sigma$ mass. The role of SMBH feedback in our model evolves in space and time with the ISM structure. In the early gas rich phase, SMBH accelerate...
We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...
The spectrum of strings on BTZ black holes and spectral flow in the SL(2,R) WZW model
Hemming, S; Hemming, Samuli; Keski-Vakkuri, Esko
2002-01-01
We study the spectrum of bosonic string theory on rotating BTZ black holes, using a SL(2,R) WZW model. Previously, Natsuume and Satoh have analyzed strings on BTZ black holes using orbifold techniques. We show how an appropriate spectral flow in the WZW model can be used to generate the twisted sectors, emphasizing how the spectral flow works in the hyperbolic basis natural for the BTZ black hole. We discuss the projection condition which leads to the quantization condition for the allowed quantum numbers for the string excitations, and its connection to the anomaly in the corresponding conserved Noether current.
Wave modelling to assess the storm conditions in the Black Sea
Rusu, Liliana; Raileanu, Alina
2014-05-01
The work proposed herewith presents the results of a ten-year wave hindcast performed in the Black Sea and focused on the storm conditions. A wave modelling system, SWAN based, was implemented in the basin of the Black Sea. Validations have been performed both against in situ and remotely sensed data for the entire ten-year period considered (1999-2008). The wind field provided by NCEP-CFSR (United States National Centers for Environmental Prediction, Climate Forecast System Reanalysis) with a spatial resolution of 0.312ºx0.312º and a temporal resolution of 3 hours was considered for forcing the wave model. In statistical terms, the results are in general in line with those provided by similar wave prediction systems implemented in enclosed or semi-enclosed seas, the most important factors in increasing the general system reliability being the accuracy and resolution of the wind fields considered. As regards the physical processes, the calibration tests performed show that whitecapping still represents the weak link in deep water wave modelling. The most relevant storm conditions encountered in this ten-year period considered were further analysed. This analysis was performed from the point of view of the intensity, location of occurrence, duration and propagation in the geographical space of the storms. Following the results of the work, the western side of the sea is more energetic and almost each year storms with significant wave heights of about eight meters are encountered in this part of the Black Sea, while in the case of the extreme storms significant wave heights even greater than eleven meters may occur. From this perspective, it can be concluded that the present work provides valuable information about the characteristics of the storm conditions and on their dynamics in the Black Sea. Moreover, this marine environment is currently subjected to high navigation traffic and to offshore operations and the strong storms that systematically occur may produce
Institute of Scientific and Technical Information of China (English)
Li Fang; Wenlong Luo
2008-01-01
BACKGROUND: Studies have shown that agmatine can reduce inhibition of neuronal regeneration by increasing cyclic adenosine monophosphate and brain-derived neurotrophic factor (BDNF) in the hippocampus of morphine-dependent rats. The hypothesis that agmatine exerts similar effects on facial nerve injury deserves further analysis.OBJECTIVE: To study the effects of peritoneal agmatine injection on BDNF levels in the rat brainstem after facial nerve injury.DESIGN, TIME AND SETTING: A controlled animal experiment was performed at the Department of Otolaryngology-Head and Neck Surgery at the Second Affiliated Hospital, Chongqing University of Medical Sciences (Chongqing, China), between October and December in 2007.MATERIALS: Twenty-four male Sprague-Dawley rats were randomly divided into a control, a lesion, and an agmatine treatment group, with eight rats in each group. Bilateral facial nerve anastomosis was induced in the lesion and agmatine treatment groups, while the control group remained untreated. A rat BDNF Enzyme-linked immunosorbent assay kit was used to measure BDNF levels in the brainstem facial nucleus.METHODS: Starting on the day of lesion, the agmatine group received a peritoneal injection of 100 mg/kg agmatine, once per day, for a week, whereas rats in the lesion group received saline injections.MAIN OUTCOME MEASURES: BDNF levels in the brainstem containing facial nucleus were measured by ELISA.RESULTS: Twenty-four rats were included in the final analysis without any loss. Two weeks after lesion, BDNF levels were significantly higher in the lesion group than in the control group (P<0.01). A significant increase was noted in the agmatine group compared to the lesion group (P<0.01).CONCLUSION: Agmatine can substantially increase BDNF levels in the rat brainstem after facial nerve injury.
Black Swans and Many Worlds: Contemporary models in music, the arts and ideas
Directory of Open Access Journals (Sweden)
Barry Barbara
2013-01-01
Full Text Available Black Swans and Many Worlds are new models to help explain musical structures, and by extension, events in the social environment and in internal human experience. Many Worlds takes its departure point from quantum physics, and especially the work of Hugh Everett III, who used the defining point of a measurement in the sub-atomic world as initiating alternative courses of action. Everett extrapolated this idea to the macro-world: a defining point may initiate multiple outcomes, each with its own character and events, as parallel worlds. One application of this model is to consider musical works within a genre as Many Worlds. Black Swans derive from Nassim Taleb, who proposes that social, political, and in fact all aspects of today’s world are not understandable by logical processes or incremental change but are often rocked by extreme, unpredictable shocks. If Many Worlds provide new ways of thinking about potentiality, probability and innovation, Black Swans arrest us in our tracks by eruptions that threaten to derail contemporary life, and with it, music, the arts and ideas.
Bayesian model selection for testing the no-hair theorem with black hole ringdowns
Gossan, S; Sathyaprakash, B S
2011-01-01
General relativity predicts that a black hole that results from the merger of two compact stars (either black holes or neutron stars) is initially highly deformed but soon settles down to a quiescent state by emitting a superposition of quasi-normal modes (QNMs). The QNMs are damped sinusoids with characteristic frequencies and decay times that depend only on the mass and spin of the black hole and no other parameter - a statement of the no-hair theorem. In this paper we have examined the extent to which QNMs could be used to test the no-hair theorem with future ground- and space-based gravitational-wave detectors. We model departures from general relativity (GR) by introducing extra parameters which change the mode frequencies or decay times from their general relativistic values. With the aid of numerical simulations and Bayesian model selection, we assess the extent to which the presence of such a parameter could be inferred, and its value estimated. We find that it is harder to decipher the departure of d...
Black-Scholes finite difference modeling in forecasting of call warrant prices in Bursa Malaysia
Mansor, Nur Jariah; Jaffar, Maheran Mohd
2014-07-01
Call warrant is a type of structured warrant in Bursa Malaysia. It gives the holder the right to buy the underlying share at a specified price within a limited period of time. The issuer of the structured warrants usually uses European style to exercise the call warrant on the maturity date. Warrant is very similar to an option. Usually, practitioners of the financial field use Black-Scholes model to value the option. The Black-Scholes equation is hard to solve analytically. Therefore the finite difference approach is applied to approximate the value of the call warrant prices. The central in time and central in space scheme is produced to approximate the value of the call warrant prices. It allows the warrant holder to forecast the value of the call warrant prices before the expiry date.
Two-dimensional models of hydrodynamical accretion flows into black holes
Igumenshchev, I V; Igumenshchev, Igor V.; Abramowicz, Marek Artur
2000-01-01
We present a systematic numerical study of two-dimensional axisymmetric accretion flows around black holes. The flows have no radiative cooling and are treated in the framework of the hydrodynamical approximation. The models calculated in this study cover the large range of the relevant parameter space. There are four types of flows, determined by the values of the viscosity parameter $\\alpha$ and the adiabatic index $\\gamma$: convective flows, large-scale circulations, pure inflows and bipolar outflows. Thermal conduction introduces significant changes to the solutions, but does not create a new flow type. Convective accretion flows and flows with large-scale circulations have significant outward-directed energy fluxes, which have important implications for the spectra and luminosities of accreting black holes.
Ingram, Adam
2015-01-01
Black hole binary systems can emit very bright and rapidly varying X-ray signals when material from the companion accretes onto the black hole, liberating huge amounts of gravitational potential energy. Central to this process of accretion is turbulence. In the propagating mass accretion rate fluctuations model, turbulence is generated throughout the inner accretion flow, causing fluctuations in the accretion rate. Fluctuations from the outer regions propagate towards the black hole, modulating the fluctuations generated in the inner regions. Here, I present the theoretical motivation behind this picture before reviewing the array of statistical variability properties observed in the light curves of black hole binaries that are naturally explained by the model. I also discuss the remaining challenges for the model, both in terms of comparison to data and in terms of including more sophisticated theoretical considerations.
Ingram, A. R.
2016-05-01
Black hole binary systems can emit very bright and rapidly varying X-ray signals when material from the companion accretes onto the black hole, liberating huge amounts of gravitational potential energy. Central to this process of accretion is turbulence. In the propagating mass accretion rate fluctuations model, turbulence is generated throughout the inner accretion flow, causing fluctuations in the accretion rate. Fluctuations from the outer regions propagate towards the black hole, modulating the fluctuations generated in the inner regions. Here, I present the theoretical motivation behind this picture before reviewing the array of statistical variability properties observed in the light curves of black hole binaries that are naturally explained by the model. I also discuss the remaining challenges for the model, both in terms of comparison to data and in terms of including more sophisticated theoretical considerations.
The Adjoint Method Formulation for an Inverse Problem in the Generalized Black-Scholes Model
Directory of Open Access Journals (Sweden)
PIERRE NGNEPIEBA
2006-08-01
Full Text Available A general framework is developed to treat optimal control problems for a generalized Black-Scholes model, which is used for option pricing. The volatility function is retrieved from a set of market observations. The optimal volatility function is found by minimizing the cost functional measuring the discrepancy between the model solution (pricing and the observed market price, via the unconstrained minimization algorithm of the quasi-Newton limited memory type. The gradient is computed via the adjoint method. The effectiveness of the method is demonstrated on an European call option.
Parameter estimation of Black-Sholes-Merton model by random observation
Vladeva, Dimitrinka I.
2015-11-01
Stochastic processes are frequently used to model various scientific problems in fields ranging from finance and biology to engineering and physical science. In this paper we consider the Black-Sholes-Merton model with constant coefficients and find the unbiased and consistent estimators for the unknown parameters when the observations are point process t0, t1, …, tn independent of the Wiener process. Here we prove good properties of the estimations without any condition of the type max 1 ≤i ≤n (ti-ti -1)→0 when n → ∞, as in other sampling schemes.
Directory of Open Access Journals (Sweden)
Andronikos Paliathanasis
2016-05-01
Full Text Available We perform a classification of the Lie point symmetries for the Black-Scholes-Merton Model for European options with stochastic volatility, σ, in which the last is defined by a stochastic differential equation with an Orstein-Uhlenbeck term. In this model, the value of the option is given by a linear (1 + 2 evolution partial differential equation in which the price of the option depends upon two independent variables, the value of the underlying asset, S, and a new variable, y. We find that for arbitrary functional form of the volatility, σ ( y , the (1 + 2 evolution equation always admits two Lie point symmetries in addition to the automatic linear symmetry and the infinite number of solution symmetries. However, when σ ( y = σ 0 and as the price of the option depends upon the second Brownian motion in which the volatility is defined, the (1 + 2 evolution is not reduced to the Black-Scholes-Merton Equation, the model admits five Lie point symmetries in addition to the linear symmetry and the infinite number of solution symmetries. We apply the zeroth-order invariants of the Lie symmetries and we reduce the (1 + 2 evolution equation to a linear second-order ordinary differential equation. Finally, we study two models of special interest, the Heston model and the Stein-Stein model.
Implementation and validation of a modeling framework to assess personal exposure to black carbon.
Dons, Evi; Van Poppel, Martine; Kochan, Bruno; Wets, Geert; Int Panis, Luc
2014-01-01
Because people tend to move from one place to another during the day, their exposure to air pollution will be determined by the concentration at each location combined with the exposure encountered in transport. In order to estimate the exposure of individuals in a population more accurately, the activity-based modeling framework for Black Carbon exposure assessment, AB(2)C, was developed. An activity-based traffic model was applied to model the whereabouts of individual agents. Exposure to black carbon (BC) in different microenvironments is assessed with a land use regression model, combined with a fixed indoor/outdoor factor for exposure in indoor environments. To estimate exposure in transport, a separate model was used taking into account transport mode, timing of the trip and degree of urbanization. The modeling framework is validated using weeklong time-activity diaries and BC exposure as revealed from a personal monitoring campaign with 62 participants. For each participant in the monitoring campaign, a synthetic population of 100 model-agents per day was made up with all agents meeting similar preconditions as each real-life agent. When these model-agents pass through every stage of the modeling framework, it results in a distribution of potential exposures for each individual. The AB(2)C model estimates average personal exposure slightly more accurately compared to ambient concentrations as predicted for the home subzone; however the added value of a dynamic model lies in the potential for detecting short term peak exposures rather than modeling average exposures. The latter may bring new opportunities to epidemiologists: studying the effect of frequently repeated but short exposure peaks on long term exposure and health. PMID:24161448
Basic mathematical model for the normal black smoker system and the hydrothermal megaplume formation
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A tube model to simulate the normal black smoker system has been built, where the Darcy flow equation, the Ergun equation and the turbulent pipe flow equation are used respectively to describe the dynamic process of different key areas in the hydrothermal circulation system. At the same time, a convection-diffuse Equation for the temperature field is used for describe the exchange of thermal energy and the law of temperature variation. Combining the above facts and using efficient mathematical algorithms and programming with the MatLab programming language, the variation curves of temperature, pressure and mass flow rate are determined, while also the dynamic heat equilibrium and pressure equilibrium within the black smoker system are analyzed. On the basis of the model of the normal black smoker system, a megaplume formation model is further built. For instance, the hydrothermal venting plume on the Juan de Fuca Ridge has been simulated and the simulation results are fairly consistent with Baker's imputed data in 1986. On the basis of the above productive simulation, a series of factors for megaplume formation and the effectiveness of the main parameters of the periodicity of the megaplume formation, temperature and the maximum mass flow rate are systematically discussed. Main conclusions are as follows: The normal black smoker system can evolve into a megaplum eruption. In fact, the passageway of the hydrothermal discharge is blocked by the hydrothermal sediments during the black smoker period, which leads to a hydrothermal fluid accumulation, rise of temperature and increase of buoyancy pressure under the seabed. After a period of 2～3 a, the megaplume hydrothermal eruption will occur when the increasing buoyancy pressure is high enough to crack the blockage (cap).Meanwhile, the temperature of the heat source must exceed 500 ℃, while the highest temperature of the eruption fluid may be high up to 413 ℃, which is fairly consistent with the surveying data
Photon Exchange in Nucleus-Nucleus Collisions
Bertulani, Carlos A.
2002-01-01
The strong electromagnetic fields in peripheral heavy ion collisions give rise to photon-photon and photon-nucleus interactions. I present a general survey of the photon-photon and photon-hadron physics accessible in these collisions. Among these processes I discuss the nuclear fragmentation through the excitation of giant resonances, the Coulomb dissociation method for application in nuclear astrophysics, and the production of particles.
Green and Black Cardamom in a Diet-Induced Rat Model of Metabolic Syndrome
Directory of Open Access Journals (Sweden)
Maharshi Bhaswant
2015-09-01
Full Text Available Both black (B and green (G cardamom are used as flavours during food preparation. This study investigated the responses to B and G in a diet-induced rat model of human metabolic syndrome. Male Wistar rats were fed either a corn starch-rich diet (C or a high-carbohydrate, high-fat diet with increased simple sugars along with saturated and trans fats (H for 16 weeks. H rats showed signs of metabolic syndrome leading to visceral obesity with hypertension, glucose intolerance, cardiovascular remodelling and nonalcoholic fatty liver disease. Food was supplemented with 3% dried B or G for the final eight weeks only. The major volatile components were the closely related terpenes, 1,8-cineole in B and α-terpinyl acetate in G. HB (high-carbohydrate, high-fat + black cardamom rats showed marked reversal of diet-induced changes, with decreased visceral adiposity, total body fat mass, systolic blood pressure and plasma triglycerides, and structure and function of the heart and liver. In contrast, HG (high-carbohydrate, high-fat + green cardamom rats increased visceral adiposity and total body fat mass, and increased heart and liver damage, without consistent improvement in the signs of metabolic syndrome. These results suggest that black cardamom is more effective in reversing the signs of metabolic syndrome than green cardamom.
The Binary Black Hole Model for Mrk 231 Cannot Explain the Observed Emission Lines
Leighly, Karen M; Gallagher, Sarah C; Lucy, Adrian B
2016-01-01
Mrk 231 is a nearby quasar with an unusually red continuum, generally explained as heavy reddening by dust (e.g., Leighly et al. 2014). Yan et al. 2015 proposed that Mrk 231 is a milli-parsec black-hole binary with little intrinsic reddening. The large-mass black hole experiences advection-dominated accretion, emitting little continuum, while the accretion disk of the small-mass black hole emits as an ordinary quasar, dominating the observed weak UV continuum and contributing all of the photoionizing flux. We demonstrate that this model is untenable for four reasons. (1) To produce the observed near-infrared emission lines, the equivalent widths would have to be ~100 times larger than typical values with respect to the photoionizing continuum, a situation that seems energetically unlikely. (2) We use the photoionization code Cloudy to demonstrate it is not possible to produce the HeI* emission line intensity for the observed HeI*/Pbeta flux ratios, even if the line-emitting gas intersects all of the photoioni...
Green and Black Cardamom in a Diet-Induced Rat Model of Metabolic Syndrome.
Bhaswant, Maharshi; Poudyal, Hemant; Mathai, Michael L; Ward, Leigh C; Mouatt, Peter; Brown, Lindsay
2015-09-11
Both black (B) and green (G) cardamom are used as flavours during food preparation. This study investigated the responses to B and G in a diet-induced rat model of human metabolic syndrome. Male Wistar rats were fed either a corn starch-rich diet (C) or a high-carbohydrate, high-fat diet with increased simple sugars along with saturated and trans fats (H) for 16 weeks. H rats showed signs of metabolic syndrome leading to visceral obesity with hypertension, glucose intolerance, cardiovascular remodelling and nonalcoholic fatty liver disease. Food was supplemented with 3% dried B or G for the final eight weeks only. The major volatile components were the closely related terpenes, 1,8-cineole in B and α-terpinyl acetate in G. HB (high-carbohydrate, high-fat + black cardamom) rats showed marked reversal of diet-induced changes, with decreased visceral adiposity, total body fat mass, systolic blood pressure and plasma triglycerides, and structure and function of the heart and liver. In contrast, HG (high-carbohydrate, high-fat + green cardamom) rats increased visceral adiposity and total body fat mass, and increased heart and liver damage, without consistent improvement in the signs of metabolic syndrome. These results suggest that black cardamom is more effective in reversing the signs of metabolic syndrome than green cardamom.
Blik, Vitaliya
2015-01-01
Deep brain stimulation (DBS) is a promising approach for epilepsy treatment, but the optimal targets and parameters of stimulation are yet to be investigated. Tuberomamillary nucleus (TMN) is involved in EEG desynchronization-one of the proposed mechanisms for DBS action. We studied whether TMN stimulation could interfere with epileptic spike-wave discharges (SWDs) in WAG/Rij rats with inherited absence epilepsy and whether such stimulation would affect sleep-wake cycle. EEG and video registration were used to determine SWD occurrence and stages of sleep and wake during three-hours recording sessions. Stimulation (100Hz) was applied in two modes: closed-loop (with previously determined interruption threshold intensity) or open-loop mode (with 50% or 70% threshold intensity). Closed-loop stimulation successfully interrupted SWDs but elevated their number by 148 ± 54% compared to baseline. It was accompanied by increase in number of episodes but not total duration of both active and passive wakefulness. Open-loop stimulation with amplitude 50% threshold did not change measured parameters, though 70% threshold stimulation reduced SWDs number by 40 ± 9%, significantly raised the amount of active wakefulness and decreased the amount of both slow-wave and rapid eye movement sleep. These results suggest that the TMN is unfavorable as a target for DBS as its stimulation may cause alterations in sleep-wake cycle. A careful choosing of parameters and control of sleep-wake activity is necessary when applying DBS in epilepsy.
Geng, Xiwen; Xie, Jinlu; Wang, Xuenan; Wang, Xiusong; Zhang, Xiao; Hou, Yabing; Lei, Chengdong; Li, Min; Qu, Qingyang; He, Tingting; Han, Hongyu; Yao, Xiaomeng; Wang, Min
2016-05-15
The pedunculopontine nucleus (PPN) is a new deep brain stimulation target for treating Parkinson's disease (PD). But the alterations of the PPN electrophysiological activities in PD are still debated. To investigate these potential alterations, extracellular single unit and local field potential (LFP) activities in the PPN were recorded in unilateral hemispheric 6-hydroxydopamine (6-OHDA) lesioned rats and in control rats, respectively. The spike activity results revealed two types of neurons (Type I and Type II) with distinct electrophysiological characteristics in the PPN. Both types of neurons had increased firing rate and changed firing pattern in lesioned rats when compared to control rats. Specifically, Type II neurons showed an increased firing rate when the rat state was switched from rest to locomotion. The LFP results demonstrated that lesioned rats had lower LFP power at 0.7-12Hz and higher power at 12-30Hz than did control animals in either resting or locomotor state. These findings provide a better understanding of the effects of 6-OHDA lesion on neuronal activities in the PPN and also provide a proof of the link between this structure and locomotion, which contributes to better understanding the mechanisms of the PPN functioning in the pathophysiology of PD. PMID:26924016
The Disk Wind Model and the Effect on the Virial Black Hole Mass Estimation
Yong, Suk Yee
2015-09-01
The current 'standard quasar model' consists of a central engine, accretion disk, and jet. However, these components cannot entirely explain some quasar spectral features, specifically, the presence of broad emission lines (BELs), which are assumed to originate from high velocity gas in the broad line region (BLR). The addition of a wind to the standard model provides a mechanism to drive the outflowing gas emanated from the accretion disk. The shape of the emission line profiles in the BLR, in particular, the velocity offsets and skewness for different viewing angles, are explored. The impact on the virial black hole mass calculation due to the quasar's orientation to the observer is also tested. The geometry of the BLR is modelled by implementing the wind component or the disk wind model. While the models are dependent on the specified parameters, they are able to qualitatively reproduce the predicted features of the emission lines.
Two-oscillator Kantowski-Sachs model of the Schwarzschild black hole interior
Djordjevic, Goran S; Radovancevic, Darko
2015-01-01
In this paper the interior of the Schwarzschild black hole, which is presented as a vacuum homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model, is considered. Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model will be presented in a classical, a p-adic and a noncommutative case. Then, within the standard quantum approach Wheeler-DeWitt equation and its general solutions, i.e. a wave function of the model, will be written, and then an adelic wave function will be constructed. Finally, thermodynamics of the model will be studied by using the Feynman-Hibbs procedure.
Two-oscillator Kantowski-Sachs model of the Schwarzschild black hole interior
Djordjevic, Goran S.; Nesic, Ljubisa; Radovancevic, Darko
2016-08-01
In this paper the interior of the Schwarzschild black hole, which is presented as a vacuum, homogeneous and anisotropic Kantowski-Sachs minisuperspace cosmological model, is considered. Lagrangian of the model is reduced by a suitable coordinate transformation to Lagrangian of two decoupled oscillators with the same frequencies and with zero energy in total (an oscillator-ghost-oscillator system). The model is presented in a classical, a p-adic and a noncommutative case. Then, within the standard quantum approach Wheeler-DeWitt equation and its general solutions, i.e. a wave function of the model is written, and then an adelic wave function is constructed. Finally, thermodynamics of the model is studied by using the Feynman-Hibbs procedure.
Two aspects of black hole entropy in Lanczos-Lovelock models of gravity
Kolekar, Sanved; Kothawala, Dawood; Padmanabhan, T.
2012-03-01
We consider two specific approaches to evaluate the black hole entropy which are known to produce correct results in the case of Einstein’s theory and generalize them to Lanczos-Lovelock models. In the first approach (which could be called extrinsic), we use a procedure motivated by earlier work by Pretorius, Vollick, and Israel, and by Oppenheim, and evaluate the entropy of a configuration of densely packed gravitating shells on the verge of forming a black hole in Lanczos-Lovelock theories of gravity. We find that this matter entropy is not equal to (it is less than) Wald entropy, except in the case of Einstein theory, where they are equal. The matter entropy is proportional to the Wald entropy if we consider a specific mth-order Lanczos-Lovelock model, with the proportionality constant depending on the spacetime dimensions D and the order m of the Lanczos-Lovelock theory as (D-2m)/(D-2). Since the proportionality constant depends on m, the proportionality between matter entropy and Wald entropy breaks down when we consider a sum of Lanczos-Lovelock actions involving different m. In the second approach (which could be called intrinsic), we generalize a procedure, previously introduced by Padmanabhan in the context of general relativity, to study off-shell entropy of a class of metrics with horizon using a path integral method. We consider the Euclidean action of Lanczos-Lovelock models for a class of metrics off shell and interpret it as a partition function. We show that in the case of spherically symmetric metrics, one can interpret the Euclidean action as the free energy and read off both the entropy and energy of a black hole spacetime. Surprisingly enough, this leads to exactly the Wald entropy and the energy of the spacetime in Lanczos-Lovelock models obtained by other methods. We comment on possible implications of the result.
Amendment of European Black- Scholes Options Pricing Model%欧式期权的Black-Scholes模型的修正
Institute of Scientific and Technical Information of China (English)
朱海燕
2005-01-01
在Black-Scholes模型的基础上,通过改变B-S模型的基本假设,给出了几种基本的修正模型及定价公式.修正后的模型使得股票价格行为更接近现实市场的运作规律,从而更有实际意义.
Testing models of supermassive black hole seed formation through gravity waves
Koushiappas, Savvas M.; Zentner, Andrew R.
2005-01-01
We study the gravitational wave background produced from the formation and assembly of supermassive black holes within the cosmological paradigm of hierarchical structure formation. In particular, we focus on a supermassive black hole formation scenario in which the present-day population of supermassive black holes is built from high-mass seed black holes and we compute the concomitant spectrum of gravitational radiation produced by mergers of the seed black holes. We find that this scenario...
A magnetic model for low/hard state of black hole binaries
Ye, Yong-Chun; Wang, Ding-Xiong; Huang, Chang-Yin; Cao, Xiao-Feng
2016-03-01
A magnetic model for the low/hard state (LHS) of two black hole X-ray binaries (BHXBs), H1743-322 and GX 339-4, is proposed based on transport of the magnetic field from a companion into an accretion disk around a black hole (BH). This model consists of a truncated thin disk with an inner advection-dominated accretion flow (ADAF). The spectral profiles of the sources are fitted in agreement with the data observed at four different dates corresponding to the rising phase of the LHS. In addition, the association of the LHS with a quasi-steady jet is modeled based on transport of magnetic field, where the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes are invoked to drive the jets from BH and inner ADAF. It turns out that the steep radio/X-ray correlations observed in H1743-322 and GX 339-4 can be interpreted based on our model.
Directory of Open Access Journals (Sweden)
Elisha Townshend
2015-09-01
Full Text Available Effective planning to optimize the forest value chain requires accurate and detailed information about the resource; however, estimates of the distribution of fibre properties on the landscape are largely unavailable prior to harvest. Our objective was to fit a model of the tree-level average fibre length related to ecosite classification and other forest inventory variables depicted at the landscape scale. A series of black spruce increment cores were collected at breast height from trees in nine different ecosite groups within the boreal forest of northeastern Ontario, and processed using standard techniques for maceration and fibre length measurement. Regression tree analysis and random forests were used to fit hierarchical classification models and find the most important predictor variables for the response variable area-weighted mean stem-level fibre length. Ecosite group was the best predictor in the regression tree. Longer mean fibre-length was associated with more productive ecosites that supported faster growth. The explanatory power of the model of fitted data was good; however, random forests simulations indicated poor generalizability. These results suggest the potential to develop localized models linking wood fibre length in black spruce to landscape-level attributes, and improve the sustainability of forest management by identifying ideal locations to harvest wood that has desirable fibre characteristics.
Shankar, Francesco; Weinberg, David H.; Miralda-Escude, Jordi
2007-01-01
We construct evolutionary models of the populations of AGN and supermassive black holes, in which the black hole mass function grows at the rate implied by the observed luminosity function, given assumptions about the radiative efficiency and the Eddington ratio. We draw on a variety of recent X-ray and optical measurements to estimate the bolometric AGN luminosity function and compare to X-ray background data and the independent estimate of Hopkins et al. (2007) to assess remaining systemati...
Dexter, Jason; Fragile, P. Chris
2012-01-01
High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion disc and black hole angular momentum axes, but this is unjustified for geometrically thick accretion flows like that onto Sgr A*. Instead, we calculate images and spectra from a set of simulations of accretion flows misaligned ('tilted') by 15 degrees from ...
Black carbon and trace gases over South Asia: Measurements and Regional Climate model simulations
Bhuyan, Pradip; Pathak, Binita; Parottil, Ajay
2016-07-01
Trace gases and aerosols are simulated with 50 km spatial resolution over South Asian CORDEX domain enclosing the Indian sub-continent and North-East India for the year 2012 using two regional climate models RegCM4 coupled with CLM4.5 and WRF-Chem 3.5. Both models are found to capture the seasonality in the simulated O3 and its precursors, NOx and CO and black carbon concentrations together with the meteorological variables over the Indian Subcontinent as well as over the sub-Himalayan North-Eastern region of India including Bangladesh. The model simulations are compared with the measurements made at Dibrugarh (27.3°N, 94.6°E, 111 m amsl). Both the models are found to capture the observed diurnal and seasonal variations in O3 concentrations with maximum in spring and minimum in monsoon, the correlation being better for WRF-Chem (R~0.77) than RegCM (R~0.54). Simulated NOx and CO is underestimated in all the seasons by both the models, the performance being better in the case of WRF-Chem. The observed difference may be contributed by the bias in the estimation of the O3 precursors NOx and CO in the emission inventories or the error in the simulation of the meteorological variables which influences O3 concentration in both the models. For example, in the pre-monsoon and winter season, the WRF-Chem model simulated shortwave flux overestimates the observation by ~500 Wm-2 while in the monsoon and post monsoon season, simulated shortwave flux is equivalent to the observation. The model predicts higher wind speed in all the seasons especially during night-time. In the post-monsoon and winter season, the simulated wind pattern is reverse to observation with daytime low and night-time high values. Rainfall is overestimated in all the seasons. RegCM-CLM4.5 is found to underestimate rainfall and other meteorological parameters. The WRF-Chem model closely captured the observed values of black carbon mass concentrations during pre-monsoon and summer monsoon seasons, but
A new perspective on Quantum Finance using the Black-Scholes pricing model
Dieng, Lamine
2007-03-01
Options are known to be divided into two types, the first type is called a call option and the second type is called a put option and these options are offered to stock holders in order to hedge their positions against risky fluctuations of the stock price. It is important to mention that due to fluctuations of the stock price, options can be found sometimes deep in the money, at the money and out of the money. A deep in the money option is described when the option's holder has a positive expected payoff, at the money option is when the option's holder has a zero expected payoff and an out of the money option is when the payoff is negative. In this work, we will assume the stock price to be described by the well known Black-Scholes model or sometimes called the multiplicative model. Using Ito calculus, Martingale and supermartingale theories, we investigated the Black-Scholes pricing equation at the money (X(stock price)= K (strike price)) when the expected payoff of the options holder is zero. We also hedged the Black-Scholes pricing equation in the limit when delta is zero to obtain the non-relativistic time independent Schroedinger equation in quantum mechanics. We compared the two equations and found the diffusion constant to be a function of the stock price in contrast to the Bachelier model we have worked on earlier. We solved the Schroedinger equation and found a dependence between interest rate, volatility and strike price at the money.
Reproduction and evaluation of a rat model of inhalation lung injury caused by black gunpowder smog
Directory of Open Access Journals (Sweden)
Yi-fan LIU
2013-09-01
Full Text Available Objective To reproduce and evaluate a rat model of inhalation lung injury caused by black gunpowder smog. Methods The smog composition was analyzed and a rat model of inhalation lung injury was reproduced. Forty two healthy male Wistar rats were randomly divided into normal control (NC group and 1h, 2h, 6h, 24h, 48h and 96h after inhalation group (n=6. The arterial blood gas, wet to dry weight ratio (W/D of lung, leukocyte count, and protein concentration in broncho-alveolar lavage fluid (BALF were determined. Macroscopic and microscopic changes in lung tissue were observed. Results The composition of black gunpowder smog was composed mainly of CO2 and CO, and their concentrations remained stable within 12 minutes. Smog inhalation caused a significant hypoxemia, the concentration of blood COHb reached a peak value 1h, and the W/D of lung reached peak value 2h after inhalation (P<0.05. The amount of leukocytes and content of protein in BALF increased significantly within 24h after inhalation (P<0.05. Histopathological observation showed diffuse hemorrhage, edema and inflammatory cell infiltration in lung tissue as manifestations of acute lung injury, and the injury did not recover at 96h after inhalation. Conclusion The rat model of inhalation lung injury can be reproduced using black gunpowder smog, and it has the advantages of its readiness for reproduction, reliability and stability, and it could be used for the experiment of inhalation injury in a battlefield environment.
International Nuclear Information System (INIS)
Data measured in hadron-nucleus interactions are studied within the framework of the multi-chain Monte Carlo fragmentation model. Average multiplicities for all charged particles and negative charged particles measured in proton-xenon, antiproton-xenon, proton-argon, antiproton-argon as well as proton-antiproton and proton-proton collisions at 200 GeV/c are compared to Monte Carlo results. Furthermore, comparisons between experimental and Monte Carlo data are presented for rapidity distributions and ratios for projectile protons and different targets. Finally, the differential cross sections Edσ/dp3 measured at fixed transverse momentum of 0.3 GeV/c and p/sub lab/ = 100 GeV/c are shown ranging between approximately 0.2 and 0.8. The Monte Carlo curves to be compared with are corrected by some factor due to the using of all transverse momenta in order to obtain the Monte Carlo results
Data Assimilation and Sensitivity of the Black Sea Model to Parameters
Kazantsev, Eugene
2011-01-01
An adjoint based technique is applied to a Shallow Water Model in order to estimate influence of the model's parameters on the solution. Among parameters the bottom topography, initial conditions, boundary conditions on rigid boundaries, viscosity coefficients and the amplitude of the wind stress tension are considered. Their influence is analyzed from different points of view. Two configurations have been analyzed: an academic case of the model in a square box and a more realistic case simulating Black Sea currents. It is shown in both experiments that the boundary conditions near a rigid boundary influence the most the solution. This fact points out the necessity to identify optimal boundary approximation during a model development.
Diameter structure modeling and the calculation of plantation volume of black poplar clones
Directory of Open Access Journals (Sweden)
Andrašev Siniša
2004-01-01
Full Text Available A method of diameter structure modeling was applied in the calculation of plantation (stand volume of two black poplar clones in the section Aigeiros (Duby: 618 (Lux and S1-8. Diameter structure modeling by Weibull function makes it possible to calculate the plantation volume by volume line. Based on the comparison of the proposed method with the existing methods, the obtained error of plantation volume was less than 2%. Diameter structure modeling and the calculation of plantation volume by diameter structure model, by the regularity of diameter distribution, enables a better analysis of the production level and assortment structure and it can be used in the construction of yield and increment tables.
The ionospheric source of magnetospheric plasma is not a black box input for global models
Welling, D. T.; Liemohn, M. W.
2016-06-01
Including ionospheric outflow in global magnetohydrodynamic models of near-Earth outer space has become an important step toward understanding the role of this plasma source in the magnetosphere. Of the existing approaches, however, few tie the outflowing particle fluxes to magnetospheric conditions in a self-consistent manner. Doing so opens the magnetosphere-ionosphere system to nonlinear mass-energy feedback loops, profoundly changing the behavior of the magnetosphere-ionosphere system. Based on these new results, it is time for the community eschew treating ionospheric outflow as a simple black box source of magnetospheric plasma.
Matrix models, 4D black holes and topological strings on non-compact Calabi-Yau manifolds
Danielsson, Ulf H.; Olsson, Martin E.; Vonk, Marcel
2004-11-01
We study the relation between c = 1 matrix models at self-dual radii and topological strings on non-compact Calabi-Yau manifolds. Particularly the special case of the deformed matrix model is investigated in detail. Using recent results on the equivalence of the partition function of topological strings and that of four dimensional BPS black holes, we are able to calculate the entropy of the black holes, using matrix models. In particular, we show how to deal with the divergences that arise as a result of the non-compactness of the Calabi-Yau. The main result is that the entropy of the black hole at zero temperature coincides with the canonical free energy of the matrix model, up to a proportionality constant given by the self-dual temperature of the matrix model.
Modeling and field observations of char bed processes in black liquor recovery boilers
Energy Technology Data Exchange (ETDEWEB)
Engblom, M.
2010-07-01
The char bed plays an important role in kraft black liquor combustion. Stable operation of the char bed promotes efficient and safe operation of the black liquor recovery boiler. It also plays a crucial role in the recovery of the pulping chemicals. Char bed operation involves controlling the char bed size and shape. Mathematical modeling based on computational fluid dynamics (CFD) haas been applied to recovery boilers for increased insights into the recovery furnace processes and to aid in the design of new boilers. So far, all CED-based char bed models reported in literature have used a fixed bed shape. This imposes restrictions on simulation of char bed burning by not considering inherently occurring changes in bed shape. In this thesis, a CED -based recovery furnace model is further developed to predict changes in bed shape. The new model is used in simulation of existing recovery boilers. The predictions of bed shape are compared with observations from real boilers. The furnace model is capable of correctly simulating the overall response of the char bed size to operational changes. This confirms the current quantitative overall understanding of char bed burning. In addition to modeling, visual observations of the char bed processes were made in this work. The observations provide validation data concerning the physical behavior of the char bed, and the findings from the observations can be used in further development of char bed models. Modeling and simulations of fundamental laboratory scale char bed experiments reported in literature are also carried out. The simulations complement the experimental data by providing detailed insights into gas phase reactions that can occur inside the gas boundary layer above a char bed. (orig.)
A fuzzy compromise programming approach for the Black-Litterman portfolio selection model
Directory of Open Access Journals (Sweden)
Mohsen Gharakhani
2013-01-01
Full Text Available In this paper, we examine advanced optimization approach for portfolio problem introduced by Black and Litterman to consider the shortcomings of Markowitz standard Mean-Variance optimization. Black and Litterman propose a new approach to estimate asset return. They present a way to incorporate the investor’s views into asset pricing process. Since the investor’s view about future asset return is always subjective and imprecise, we can represent it by using fuzzy numbers and the resulting model is multi-objective linear programming. Therefore, the proposed model is analyzed through fuzzy compromise programming approach using appropriate membership function. For this purpose, we introduce the fuzzy ideal solution concept based on investor preference and indifference relationships using canonical representation of proposed fuzzy numbers by means of their correspondingα-cuts. A real world numerical example is presented in which MSCI (Morgan Stanley Capital International Index is chosen as the target index. The results are reported for a portfolio consisting of the six national indices. The performance of the proposed models is compared using several financial criteria.
Inner Structure of Boiling Nucleus and Interfacial Energy Between Nucleus and Bulk Liquid
Institute of Scientific and Technical Information of China (English)
WANG Xiao-Dong; TIAN Yong; PENG Xiao-Feng; WANG Bu-Xuan
2004-01-01
@@ A model of two-region structure of a nucleus is proposed to describe nucleus evolution. The interfacial tension between bulk liquid phase and nucleus is dependent on the density gradient in the transition region and varies with the structure change of the transition region. With the interfacial tension calculated using this model, the predicted nucleation rate is very close to the experimental measurement. Furthermore, this model and associated analysis provide solid theoretical evidence to clarify the definition of nucleation rate and understand the nucleation phenomenon with insight into the physical nature.
Modelling of Black and Organic Carbon Variability in the Northern Hemisphere
Kurganskiy, Alexander; Nuterman, Roman; Mahura, Alexander; Kaas, Eigil; Baklanov, Alexander; Hansen Sass, Bent
2016-04-01
Black and organic carbon as short-lived climate forcers have influence on air quality and climate in Northern Europe and Arctic. Atmospheric dispersion, deposition and transport of these climate forcers from remote sources is especially difficult to model in Arctic regions due to complexity of meteorological and chemical processes and uncertainties of emissions. In our study, the online integrated meteorology-chemistry/aerosols model Enviro-HIRLAM (Environment - High Resolution Limited Area Model) was employed for evaluating spatio-temporal variability of black and organic carbon aerosols in atmospheric composition in the Northern Hemisphere regions. The model setup included horizontal resolution of 0.72 deg, time step of 450 sec, 6 h meteorological surface data assimilation, 1 month spin-up; and model was run for the full year of 2010. Emissions included anthropogenic (ECLIPSE), shipping (AU_RCP&FMI), wildfires (IS4FIRES), and interactive sea salt, dust and DMS. Meteorological (from IFS at 0.75 deg) and chemical (from MACC Reanalysis at 1.125 deg) boundary conditions were obtained from ECMWF. Annual and month-to-month variability of mean concentration, accumulated dry/wet and total deposition fluxes is analyzed for the model domain and selected European and Arctic observation sites. Modelled and observed BC daily mean concentrations during January and July showed fair-good correlation (0.31-0.64) for stations in Germany, UK and Italy; however, for Arctic stations (Tiksi, Russia and Zeppelin, Norway) the correlations were negative in January, but higher correlations and positive (0.2-0.7) in July. For OC, it varied 0.45-0.67 in January and 0.19-0.57 in July. On seasonal scale, during both summer and winter seasons the BC and OC correlations are positive and higher for European stations compared with Arctic. On annual scale, both BC and OC correlations are positive and vary between 0.4-0.6 for European stations, and these are smoothed to negligible values for Arctic
Testing string dynamics in lepton nucleus reactions
International Nuclear Information System (INIS)
The sensitivity of nuclear attenuation of 10-100 GeV lepton nucleus (ell A) reactions to space-time aspects of hadronization is investigated within the context of the Lund string model. We consider two mechanisms for attenuation in a nucleus: final state cascading and string flip excitations. Implications for the evolution of the energy density in nuclear collisions are discussed. 16 refs., 10 figs
Directory of Open Access Journals (Sweden)
Yohan J John
2016-02-01
Full Text Available In a complex environment that contains both opportunities and threats, it is important for an organism to flexibly direct attention based on current events and prior plans. The amygdala, the hub of the brain's emotional system, is involved in forming and signaling affective associations between stimuli and their consequences. The inhibitory thalamic reticular nucleus (TRN is a hub of the attentional system that gates thalamo-cortical signaling. In the primate brain, a recently discovered pathway from the amygdala sends robust projections to TRN. Here we used computational modeling to demonstrate how the amygdala-TRN pathway, embedded in a wider neural circuit, can mediate selective attention guided by emotions. Our Emotional Gatekeeper model demonstrates how this circuit enables focused top-down, and flexible bottom-up, allocation of attention. The model suggests that the amygdala-TRN projection can serve as a unique mechanism for emotion-guided selection of signals sent to cortex for further processing. This inhibitory selection mechanism can mediate a powerful affective 'framing' effect that may lead to biased decision-making in highly charged emotional situations. The model also supports the idea that the amygdala can serve as a relevance detection system. Further, the model demonstrates how abnormal top-down drive and dysregulated local inhibition in the amygdala and in the cortex can contribute to the attentional symptoms that accompany several neuropsychiatric disorders.
John, Yohan J; Zikopoulos, Basilis; Bullock, Daniel; Barbas, Helen
2016-02-01
In a complex environment that contains both opportunities and threats, it is important for an organism to flexibly direct attention based on current events and prior plans. The amygdala, the hub of the brain's emotional system, is involved in forming and signaling affective associations between stimuli and their consequences. The inhibitory thalamic reticular nucleus (TRN) is a hub of the attentional system that gates thalamo-cortical signaling. In the primate brain, a recently discovered pathway from the amygdala sends robust projections to TRN. Here we used computational modeling to demonstrate how the amygdala-TRN pathway, embedded in a wider neural circuit, can mediate selective attention guided by emotions. Our Emotional Gatekeeper model demonstrates how this circuit enables focused top-down, and flexible bottom-up, allocation of attention. The model suggests that the amygdala-TRN projection can serve as a unique mechanism for emotion-guided selection of signals sent to cortex for further processing. This inhibitory selection mechanism can mediate a powerful affective 'framing' effect that may lead to biased decision-making in highly charged emotional situations. The model also supports the idea that the amygdala can serve as a relevance detection system. Further, the model demonstrates how abnormal top-down drive and dysregulated local inhibition in the amygdala and in the cortex can contribute to the attentional symptoms that accompany several neuropsychiatric disorders. PMID:26828203
Emergent horizon, Hawking radiation and chaos in the collapsed polymer model of a black hole
Brustein, Ram
2016-01-01
We have proposed that the interior of a macroscopic Schwarzschild black hole (BH) consists of highly excited, long, closed, interacting strings and, as such, can be modeled as a collapsed polymer. It was previously shown that the scaling relations of the collapsed-polymer model agree with those of the BH. The current paper further substantiates this proposal with an investigation into some of its dynamical consequences. In particular, we show that the model predicts, without relying on gravitational effects, an emergent horizon. We further show that the horizon fluctuates quantum mechanically as it should and that the strength of the fluctuations is inversely proportional to the BH entropy. It is then demonstrated that the emission of Hawking radiation is realized microscopically by the quantum-induced escape of small pieces of string, with the rate of escape and the energy per emitted piece both parametrically matching the Hawking temperature. We also show, using standard methods from statistical mechanics a...
GENIE implementation of IFIC Valencia model for QE-like 2p2h neutrino-nucleus cross section
Schwehr, J; Gran, R
2016-01-01
The model by Nieves, Ruiz-Simo, and Vicente-Vacas and their group (IFIC, Valencia, Spain) for 2p2h reactions that produce QE-like (no pion) final states has been implemented in GENIE. Since the model currently does not predict the kinematics of the outgoing hadrons, a simple two-nucleon system is grafted onto the model's prediction of isospin, energy transfer, and momentum transfer. These two nucleons are then given to the GENIE FSI models. This whitepaper is a guide to the kind of information available from this model and some limitations. There are several figures that illustrate the output of the model, and detailed discussion of the physics context for this model. Finally, any other authors' model (or variations of this one) that can be expressed as hadronic tensors for total and pn initial state will be easy to incorporate into this framework.
Zubkov, V. S.
2012-07-06
We present a mathematical model describing the spatial distribution of tear film osmolarity across the ocular surface of a human eye during one blink cycle, incorporating detailed fluid and solute dynamics. Based on the lubrication approximation, our model comprises three coupled equations tracking the depth of the aqueous layer of the tear film, the concentration of the polar lipid, and the concentration of physiological salts contained in the aqueous layer. Diffusive boundary layers in the salt concentration occur at the thinnest regions of the tear film, the black lines. Thus, despite large Peclet numbers, diffusion ameliorates osmolarity around the black lines, but nonetheless is insufficient to eliminate the build-up of solute in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical saccadic eyelid motion can reduce osmolarity at the lower black line, raising the prospect that select eyeball motions more generally can assist in alleviating tear film hyperosmolarity. Finally, our results indicate that measured evaporative rates will induce excessive hyperosmolarity at the black lines, even for the healthy eye. This suggests that further evaporative retardation at the black lines, for instance due to the cellular glycocalyx at the ocular surface or increasing concentrations of mucus, will be important for controlling hyperosmolarity as the black line thins. © 2012 Society for Mathematical Biology.
Two Aspects of Black hole entropy in Lanczos-Lovelock models of gravity
Kolekar, Sanved; Padmanabhan, T
2011-01-01
We consider two specific approaches to evaluate the black hole entropy which are known to produce correct results in the case of Einstein's theory and generalize them to Lanczos-Lovelock models. In the first approach (which could be called extrinsic) we use a procedure motivated by earlier work by Pretorius, Vollick and Israel, and by Oppenheim, and evaluate the entropy of a configuration of densely packed gravitating shells on the verge of forming a black hole in Lanczos-Lovelock theories of gravity. We find that this matter entropy is not equal to (it is less than) Wald entropy, except in the case of Einstein theory, where they are equal. The matter entropy is proportional to the Wald entropy if we consider a specific m-th order Lanczos-Lovelock model, with the proportionality constant depending on the spacetime dimensions D and the order m of the Lanczos-Lovelock theory as (D-2m)/(D-2). Since the proportionality constant depends on m, the proportionality between matter entropy and Wald entropy breaks down ...
Quiescence Correlates Strongly with Directly Measured Black Hole Mass in Central Galaxies
Terrazas, Bryan A.; Bell, Eric F.; Henriques, Bruno M. B.; White, Simon D. M.; Cattaneo, Andrea; Woo, Joanna
2016-10-01
Roughly half of all stars reside in galaxies without significant ongoing star formation. However, galaxy formation models indicate that it is energetically challenging to suppress the cooling of gas and the formation of stars in galaxies that lie at the centers of their dark matter halos. In this Letter, we show that the dependence of quiescence on black hole and stellar mass is a powerful discriminant between differing models for the mechanisms that suppress star formation. Using observations of 91 star-forming and quiescent central galaxies with directly measured black hole masses, we find that quiescent galaxies host more massive black holes than star-forming galaxies with similar stellar masses. This observational result is in qualitative agreement with models that assume that effective, more-or-less continuous active galactic nucleus feedback suppresses star formation, strongly suggesting the importance of the black hole in producing quiescence in central galaxies.
Effect of pulping variables on enthalpy of kraft black liquors: Empirical predictive models
Energy Technology Data Exchange (ETDEWEB)
Zaman, A.A.; Fricke, A.L. [Univ. of Florida, Gainesville, FL (United States). Dept. of Chemical Engineering
1996-07-01
The effects of pulping variables on enthalpy of slash pine kraft black liquors from a 2{sup k} + 2k + 1 (k = 4) central composite design pulping experiments that were performed in a large pilot scale digester have been studied. The four cooling variables were effective alkali, sulfidity, cooking temperature, and time at temperature. In all cases, the white liquor was adjusted to a causticizing efficiency of 85% and a reduction of 93% with Na{sub 2}CO{sub 3} and Na{sub 2}SO{sub 4}. The enthalpy of these liquors was determined over wide ranges of temperature and solids concentrations using a Setaram C-80 calorimeter. In this work, previous models for enthalpy-concentration relations were used to perform a systematic study on the effects of pulping conditions on enthalpy and to develop statistically based quantitative models for enthalpy as a function of pulping variables. These results are presented, and their utility is discussed.
CHANGES IN BIOLOGICAL PROPERTIES OF ORDINARY BLACK SOILS AT GLEYISATION (MODEL EXPERIMENT
Directory of Open Access Journals (Sweden)
Kandashova K. A.
2015-10-01
Full Text Available The article presents the results of laboratory modeling of gleyisation and its effect on the biological properties of soils with stagnant regime in ordinary black soils. Gleyisation is a complex biochemical process that occurs under oxygen reduction conditions. Anaerobic microorganisms, the presence of organic substances, and the constant or prolonged waterlogging of individual horizons or the entire soil profile promote gleyisation. Model experiments revealed that gleyisation increase the total number of bacteria and suppresses number of actinomycetes, micromycetes and growth of fungal mycelium. Gleyisation decreases the activity of oxidoreductases and increases the hydrolases activity. In addition, the second content of humus slightly increases and active acidity (pH changes to neutral. Accumulation of large amounts of iron oxide (II in soil is revealed
UNCOVERING THE NUCLEUS CANDIDATE FOR NGC 253
Energy Technology Data Exchange (ETDEWEB)
Günthardt, G. I.; Camperi, J. A. [Observatorio Astronómico, Universidad Nacional de Córdoba (Argentina); Agüero, M. P. [Observatorio Astronómico, Universidad Nacional de Córdoba, and CONICET (Argentina); Díaz, R. J.; Gomez, P. L.; Schirmer, M. [Gemini Observatory, AURA (United States); Bosch, G., E-mail: gunth@oac.uncor.edu, E-mail: camperi@oac.uncor.edu, E-mail: mpaguero@oac.uncor.edu, E-mail: rdiaz@gemini.edu, E-mail: pgomez@gemini.edu, E-mail: mschirmer@gemini.edu, E-mail: guille@fcaglp.unlp.edu.ar [Instituto de Astrofísica de La Plata (CONICET-UNLP) (Argentina)
2015-11-15
NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini South we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H{sub 2} rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this
Pannarale, Francesco; Rezzolla, Luciano
2010-01-01
The merger of a binary system composed of a black hole and a neutron star may leave behind a torus of hot, dense matter orbiting around the black hole. While numerical-relativity simulations are necessary to simulate this process accurately, they are also computationally expensive and unable at present to cover the large space of possible parameters, which include the relative mass ratio, the stellar compactness and the black hole spin. To mitigate this and provide a first reasonable coverage of the space of parameters, we have developed a method for estimating the mass of the remnant torus from black hole-neutron star mergers. The toy model makes use of the relativistic affine model to describe the tidal deformations of an extended tri-axial ellipsoid orbiting around a Kerr black hole and measures the mass of the remnant torus by considering which of the fluid particles composing the star are on bound orbits at the time of the tidal disruption. We tune the toy model by using the results of fully general-rela...
Numerical modeling of the central Black Sea ecosystem functioning during the eutrophication phase
Grégoire, M.; Raick, C.; Soetaert, K.
2008-03-01
A one-dimensional coupled physical-biogeochemical model has been developed to simulate the ecosystem of the central Black Sea at the end of the 1980s when eutrophication and invasion by gelatinous organisms seriously affected the stability and dynamics of the system. The physical model is the General Ocean Turbulence Model (GOTM) and the biogeochemical model describes the foodweb from bacteria to gelatinous carnivores through 24 state variables including three groups of phytoplankton: diatoms, small phototrophic flagellates and dinoflagellates, two zooplankton groups: micro- and mesozooplankton, two groups of gelatinous zooplankton: the omnivorous and carnivorous forms, an explicit representation of the bacterial loop: bacteria, labile and semi-labile dissolved organic matter, particulate organic matter. The model simulates oxygen, nitrogen, silicate and carbon cycling. In addition, an innovation of this model is that it explicitly represents processes in the anoxic layer. Biogeochemical processes in anaerobic conditions have been represented using an approach similar to that used in the modeling of diagenetic processes in the sediments lumping together all the reduced substances in one state variable [Soetaert, K., Herman, P., 1996. A model of early diagenetic processes from the shelf to abyssal depths. Geochimica et Cosmochimica Acta 60 (6) 1019-1040]. In this way, processes in the upper oxygenated layer are fully coupled with anaerobic processes in the deep waters, allowing to perform longterm simulations. The mathematical modeling of phytoplankton and zooplankton dynamics, detritus and the microbial loop is based on the model developed by Van den Meersche et al. [Van den Meersche, K., Middelburg, J., Soetaert, K., van Rijswijk P.H.B., Heip, C., 2004. Carbon-nitrogen coupling and algal-bacterial interactions during an experimental bloom: Modeling a 13c tracer experiment. Limnology and Oceanography 49 (3), 862-878] and tested in the modeling of mesocosm
Generalized 2d-dilaton models, the true black hole and quantum integrability
Katanaev, M O; Liebl, H; Vasilevich, D V
1997-01-01
All 1+1 dimensional dipheomorphism-invariant models can be viewed in a unified manner. This includes also general dilaton theories and especially spherically symmetric gravity (SSG) and Witten's dilatonic black hole (DBH). A common feature --- also in the presence of matter fields of any type --- is the appearance of an absolutely conserved quantity C which is determined by the influx of matter. Only for a subclass of generalized dilaton theories the singularity structure vanishes together with C. Such `physical' theories include, of course, SSG and DBH. It seems to have been overlooked until recently that the (classical) 'black hole' singularity of the DBH deviates from SSG in a physically nontrivial manner. At the quantum level for all generalized dilaton theories --- in the absence of matter --- the local quantum effects are shown to disappear. This enables us to compute e.g. the second loop order correction to the Polyakov term. For non-minimal scalar coupling we also believe to have settled the controver...
Black hole solutions to the $F_4$-model and their orbits (I)
Chemissany, W; Ruggeri, D; Trigiante, M
2012-01-01
In this paper we continue the program of the classification of nilpotent orbits using the approach developed in arXiv:1107.5986, within the study of black hole solutions in D=4 supergravities. Our goal in this work is to classify static, single center black hole solutions to a specific N=2 four dimensional "magic" model, with special K\\"ahler scalar manifold ${\\rm Sp}(6,\\mathbb{R})/{\\rm U}(3)$, as orbits of geodesics on the pseudo-quaternionic manifold ${\\rm F}_{4(4)}/[{\\rm SL}(2,\\mathbb{R})\\times {\\rm Sp}(6,\\mathbb{R})]$ with respect to the action of the isometry group ${\\rm F}_{4(4)}$. Our analysis amounts to the classification of the orbits of the geodesic "velocity" vector with respect to the isotropy group $H^*={\\rm SL}(2,\\mathbb{R})\\times {\\rm Sp}(6,\\mathbb{R})$, which include a thorough classification of the \\emph{nilpotent orbits} associated with extremal solutions and reveals a richer structure than the one predicted by the $\\beta-\\gamma$ labels alone, based on the Kostant Sekiguchi approach. We prov...
Konchakovski, V. P.; Hauer, M.; Torrieri, G.; Gorenstein, M. I.; Bratkovskaya, E. L.
2008-01-01
We discuss the effects of initial collision geometry and centrality bin definition on correlation and fluctuation observables in nucleus-nucleus collisions. We focus on the forward-backward correlation coefficient recently measured by the STAR Collaboration in Au+Au collisions at RHIC. Our study is carried out within two models: the Glauber Monte Carlo code with a `toy' wounded nucleon model and the hadron-string dynamics (HSD) transport approach. We show that strong correlations can arise du...
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.
Tanaka, Takamitsu
2011-12-01
Supermassive black holes permeate the observable Universe, residing in the nuclei of all or nearly all nearby massive galaxies and powering luminous quasars as far as ten billion light years away. These monstrous objects must grow through a combination of gas accretion and mergers of less massive black holes. The direct detection of the mergers by future gravitational-wave detectors will be a momentous scientific achievement, providing tests of general relativity and revealing the cosmic evolution of supermassive black holes. An additional --- and arguably equally rewarding --- challenge is the concomitant observation of merging supermassive black holes with both gravitational and electromagneticwaves. Such synergistic, "multi-messenger" studies can probe the expansion history of the Universe and shed light on the details of accretion astrophysics. This thesis examines the mergers of supermassive black hole binaries and the observable signatures of these events. First, we consider the formation scenarios for the earliest supermassive black holes. This investigation is motivated by the Sloan Digital Sky Survey observation of a quasar that appears to be powered by a supermassive black hole with a mass of billions of solar masses, already in place one billion years after the Big Bang. Second, we develop semianalytic, time-dependent-models for the thermal emission from circumbinary gas disks around merging black holes. Our calculations corroborate the qualitative conclusion of a previous study that for black hole mergers detectable by a space-based gravitational-wave observatory, a gas disk near the merger remnant may exhibit a dramatic brightening of soft X-rays on timescales of several years. Our results suggest that this "afterglow" may become detectable more quickly after the merger than previously estimated. Third, we investigate whether these afterglow episodes could be observed serendipitously by forthcoming wide-field, high-cadence electromagnetic surveys
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. ...
Spatial planning modeling in ICZM implementation for Black Sea- case study Sulina
Nichersu, Iuliana; Marin, Eugenia; Nichersu, Iulian; Mierla, Marian; Trifanov, Cristian
2013-04-01
The purpose of this paper is to present the results of modeling the spatial planning system in the context of implementation the Protocol for Integrated Coastal Zone Management (ICZM) in the area of Sulina, on the Romanian coastal zone of Black Sea. Spatial Planning system in coastal zone is complex and composed by a big number of factors (identified from all its' components: environment, social, economic and cultural), with multivalent connections. By describing and considering the relationships between the identified factors related to the aspects of coastal zone Sulina we obtain a detailed model of this spatial planning system.This modeling process helps us to visualize the entire systems' dynamics and it is very important for future developments (scenarios, forward looking studies, etc.). The spatial planning system model is use to develop ideas, to use the complex process or predict possible evolution of coastal zone management. Romania already has the legal basis for the implementation of ICZM Protocol, which is very important for the spatial planning system in the coastal zone and aspires towards an efficient coastal zone management. This positive aspect is revealed also in the model and gives the system a beneficial evolution. The results of modeling show how spatial planning is strongly influenced by other factors, in various stages of analysis.One of the most important observations is that spatial planning in the coastal zone is influenced in similar ways by all its' four components, but there are still differences in the evolution of this process.
Gruenbaum, Shaun E; Wang, Helen; Zaveri, Hitten P; Tang, Amber B; Lee, Tih-Shih W; Eid, Tore; Dhaher, Roni
2015-10-01
The prevalence of depression and suicide is increased in patients with mesial temporal lobe epilepsy (MTLE); however, the underlying mechanism remains unknown. Anhedonia, a core symptom of depression that is predictive of suicide, is common in patients with MTLE. Glutamine synthetase, an astrocytic enzyme that metabolizes glutamate and ammonia to glutamine, is reduced in the amygdala in patients with epilepsy and depression and in suicide victims. Here, we sought to develop a novel model of anhedonia in MTLE by testing the hypothesis that deficiency in glutamine synthetase in the central nucleus of the amygdala (CeA) leads to epilepsy and comorbid anhedonia. Nineteen male Sprague-Dawley rats were implanted with an osmotic pump infusing either the glutamine synthetase inhibitor methionine sulfoximine [MSO (n=12)] or phosphate buffered saline [PBS (n=7)] into the right CeA. Seizure activity was monitored by video-intracranial electroencephalogram (EEG) recordings for 21days after the onset of MSO infusion. Sucrose preference, a measure of anhedonia, was assessed after 21days. Methionine sulfoximine-infused rats exhibited recurrent seizures during the monitoring period and showed decreased sucrose preference over days when compared with PBS-infused rats (pglutamine synthetase activity in the CeA is a possible common cause of anhedonia and seizures in TLE. We propose that the MSO CeA model can be used for mechanistic studies that will lead to the development and testing of novel drugs to prevent seizures, depression, and suicide in patients with TLE.
Merica, H
2011-01-01
Little attention has gone into linking to its neuronal substrates the dynamic structure of non-rapid-eye-movement (NREM) sleep, defined as the pattern of time-course power in all frequency bands across an entire episode. Using the spectral power time-courses in the sleep electroencephalogram (EEG), we showed in the typical first episode, several moves towards-and-away from deep sleep, each having an identical pattern linking the major frequency bands beta, sigma and delta. The neuronal transition probability model (NTP) - in fitting the data well - successfully explained the pattern as resulting from stochastic transitions of the firing-rates of the thalamically-projecting brainstem-activating neurons, alternating between two steady dynamic-states (towards-and-away from deep sleep) each initiated by a so-far unidentified flip-flop. The aims here are to identify this flip-flop and to demonstrate that the model fits well all NREM episodes, not just the first. Using published data on suprachiasmatic nucleus (SCN...
Simulating the Black Saturday 2009 UTLS Smoke Plume with an Interactive Composition-Climate Model
Field, R. D.; Luo, M.; Fromm, M. D.; Voulgarakis, A.; Mangeon, S.; Worden, J. R.
2015-12-01
Pyroconvective smoke plumes from large fires can be injected directly into the geostrophic flow and dry air at high altitudes. As a result, they are usually longer-lived, can be transported thousands of kilometers, and can cross the tropopause into the lower stratosphere. Because the emissions pulses are so abrupt relative to other non-volcanic sources, their evolution and decay can be easily separated from background levels of aerosols and trace gases. This makes them interesting natural experiments against which to evaluate models, and understand the fate and effects of surface emissions pulses. We have simulated the well-observed February 2009 Black Saturday smoke plume from southeast Australia using the NASA GISS Earth System Model. To the best of our knowledge, this represents the first simulation of a high altitude smoke plume with a full-complexity composition-climate model. We compared simulated CO to a joint retrieval from the Aura Tropospheric Emission Spectrometer and Microwave Limb Sounder instruments. Using an upper tropospheric injection height, we were able to simulate the plume's eastward transport and ascent over New Zealand, anticyclonic circulation and ascent over the Coral Sea, westward transport in the lower tropical stratosphere, and arrival over Africa at the end of February. Simulations were improved by taking into account hourly variability in emissions associated with extreme fire behavior observed by fire management agencies. We considered a range of emissions amounts, based on different assumptions about which of the Black Saturday fires were explosive enough to inject smoke to high altitudes, and accounting for emissions factor uncertainty. The best agreement between plume concentrations at the end of February was found for the highest emissions scenario. Three days after the fire, there was a linear relationship between emissions amount and plume concentration. Three weeks after the fire, the relationship was non-linear; we discuss
Cold, clumpy accretion onto an active supermassive black hole
Tremblay, Grant R; Combes, Françoise; Salomé, Philippe; O'Dea, Christopher P; Baum, Stefi A; Voit, G Mark; Donahue, Megan; McNamara, Brian R; Davis, Timothy A; McDonald, Michael A; Edge, Alastair C; Clarke, Tracy E; Galván-Madrid, Roberto; Bremer, Malcolm N; Edwards, Louise O V; Fabian, Andrew C; Hamer, Stephen L; Li, Yuan; Maury, Anaëlle; Russell, Helen R; Quillen, Alice C; Urry, C Megan; Sanders, Jeremy S; Wise, Michael
2016-01-01
Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds - a departure from the "hot mode" accretion model - although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z=0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities can precipitate from this hot gas, producing a rain of c...
Institute of Scientific and Technical Information of China (English)
林汉燕; 邓国和
2012-01-01
In this paper based on the assumption of the fractional Black-Scholes model, the classical quadratic approximation in the Black-Scholes model is applied to pricing A-merican options with continuous-paying dividends, similar approximate formulas are derived, and the influence of dividends on early exercise of American options is analyzed.%在分数次Black-Scholes模型下,应用二次近似法推导连续支付红利的美式期权定价的近似公式,并根据公式分析红利对美式期权提前实施的影响.
The "quiescent" black hole in M87
Reynolds, C S; Fabian, A C; Hwang, U; Canizares, C R
1996-01-01
It is believed that most giant elliptical galaxies possess nuclear black holes with masses in excess of $10^8\\Msun$. Bondi accretion from the interstellar medium might then be expected to produce quasar-like luminosities from the nuclei of even quiescent elliptical galaxies. It is a puzzle that such luminosities are not observed. Motivated by this problem, Fabian & Rees have recently suggested that the final stages of accretion in these objects occurs in an advection-dominated mode with a correspondingly small radiative efficiency. Despite possessing a long-known active nucleus and dynamical evidence for a black hole, the low radiative and kinetic luminosities of the core of M87 provide the best illustration of this problem. We examine an advection-dominated model for the nucleus of M87 and show that accretion at the Bondi rate is compatible with the best known estimates for the core flux from radio through to X-ray wavelengths. The success of this model prompts us to propose that FR-I radio galaxies and ...
Dexter, Jason
2012-01-01
High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion disc and black hole angular momentum axes, but this is unjustified for geometrically thick accretion flows like that onto Sgr A*. Instead, we calculate images and spectra from a set of simulations of accretion flows misaligned ('tilted') by 15 degrees from the black hole spin axis and compare them with millimetre (mm) to near-infrared (NIR) observations. Non-axisymmetric standing shocks from eccentric fluid orbits dominate the emission, leading to a wide range of possible image morphologies. These effects invalidate previous parameter estimates from model fitting, including estimates of the dimensionless black hole spin, except possibly at low values of spin or tilt. At 1.3mm, the images have crescent morphologies, and the black hole shadow may still be accessible to future...
Nieuwenhuijsen, Mark J; Donaire-Gonzalez, David; Rivas, Ioar; de Castro, Montserrat; Cirach, Marta; Hoek, Gerard; Seto, Edmund; Jerrett, Michael; Sunyer, Jordi
2015-03-01
Novel technologies, such as smartphones and small personal continuous air pollution sensors, can now facilitate better personal estimates of air pollution in relation to location. Such information can provide us with a better understanding about whether and how personal exposures relate to residential air pollution estimates, which are normally used in epidemiological studies. The aims of this study were to examine (1) the variability in personal air pollution levels during the day and (2) the relationship between modeled home and school estimates and continuously measured personal air pollution exposure levels in different microenvironments (e.g., home, school, and commute). We focused on black carbon as an indicator of traffic-related air pollution. We recruited 54 school children (aged 7-11) from 29 different schools around Barcelona as part of the BREATHE study, an epidemiological study of the relation between air pollution and brain development. For 2 typical week days during 2012-2013, the children were given a smartphone with CalFit software to obtain information on their location and physical activity level and a small sensor, the micro-aethalometer model AE51, to measure their black carbon levels simultaneously and continuously. We estimated their home and school exposure to PM2.5 filter absorbance, which is well-correlated with black carbon, using a temporally adjusted PM2.5 absorbance land use regression (LUR) model. We found considerable variation in the black carbon levels during the day, with the highest levels measured during commuting periods (geometric mean = 2.8 μg/m(3)) and the lowest levels at home (geometric mean = 1.3 μg/m(3)). Hourly temporally adjusted LUR model estimates for the home and school showed moderate to good correlation with measured personal black carbon levels at home and school (r = 0.59 and 0.68, respectively) and lower correlation with commuting trips (r = 0.32 and 0.21, respectively). The correlation between modeled home
Nieuwenhuijsen, Mark J; Donaire-Gonzalez, David; Rivas, Ioar; de Castro, Montserrat; Cirach, Marta; Hoek, Gerard; Seto, Edmund; Jerrett, Michael; Sunyer, Jordi
2015-03-01
Novel technologies, such as smartphones and small personal continuous air pollution sensors, can now facilitate better personal estimates of air pollution in relation to location. Such information can provide us with a better understanding about whether and how personal exposures relate to residential air pollution estimates, which are normally used in epidemiological studies. The aims of this study were to examine (1) the variability in personal air pollution levels during the day and (2) the relationship between modeled home and school estimates and continuously measured personal air pollution exposure levels in different microenvironments (e.g., home, school, and commute). We focused on black carbon as an indicator of traffic-related air pollution. We recruited 54 school children (aged 7-11) from 29 different schools around Barcelona as part of the BREATHE study, an epidemiological study of the relation between air pollution and brain development. For 2 typical week days during 2012-2013, the children were given a smartphone with CalFit software to obtain information on their location and physical activity level and a small sensor, the micro-aethalometer model AE51, to measure their black carbon levels simultaneously and continuously. We estimated their home and school exposure to PM2.5 filter absorbance, which is well-correlated with black carbon, using a temporally adjusted PM2.5 absorbance land use regression (LUR) model. We found considerable variation in the black carbon levels during the day, with the highest levels measured during commuting periods (geometric mean = 2.8 μg/m(3)) and the lowest levels at home (geometric mean = 1.3 μg/m(3)). Hourly temporally adjusted LUR model estimates for the home and school showed moderate to good correlation with measured personal black carbon levels at home and school (r = 0.59 and 0.68, respectively) and lower correlation with commuting trips (r = 0.32 and 0.21, respectively). The correlation between modeled home
Running spectral index and formation of primordial black hole in single field inflation models
International Nuclear Information System (INIS)
A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of long-lived Primordial Black Holes (PBHs). To that end we calculate the spectral index of the power spectrum of primordial perturbations as well as its first and second derivatives. PBH formation is possible only if the spectral index increases significantly at small scales, i.e. large wave number k. Since current data indicate that the first derivative αS of the spectral index nS(k0) is negative at the pivot scale k0, PBH formation is only possible in the presence of a sizable and positive second derivative (''running of the running'') βS. Among the three small-field and five large-field models we analyze, only one small-field model, the ''running mass'' model, allows PBH formation, for a narrow range of parameters. We also note that none of the models we analyze can accord for a large and negative value of αS, which is weakly preferred by current data
Inverse Optimization: A New Perspective on the Black-Litterman Model.
Bertsimas, Dimitris; Gupta, Vishal; Paschalidis, Ioannis Ch
2012-12-11
The Black-Litterman (BL) model is a widely used asset allocation model in the financial industry. In this paper, we provide a new perspective. The key insight is to replace the statistical framework in the original approach with ideas from inverse optimization. This insight allows us to significantly expand the scope and applicability of the BL model. We provide a richer formulation that, unlike the original model, is flexible enough to incorporate investor information on volatility and market dynamics. Equally importantly, our approach allows us to move beyond the traditional mean-variance paradigm of the original model and construct "BL"-type estimators for more general notions of risk such as coherent risk measures. Computationally, we introduce and study two new "BL"-type estimators and their corresponding portfolios: a Mean Variance Inverse Optimization (MV-IO) portfolio and a Robust Mean Variance Inverse Optimization (RMV-IO) portfolio. These two approaches are motivated by ideas from arbitrage pricing theory and volatility uncertainty. Using numerical simulation and historical backtesting, we show that both methods often demonstrate a better risk-reward tradeoff than their BL counterparts and are more robust to incorrect investor views.
Black holes as random particles: entanglement dynamics in infinite range and matrix models
Magán, Javier M.
2016-08-01
We first propose and study a quantum toy model of black hole dynamics. The model is unitary, displays quantum thermalization, and the Hamiltonian couples every oscillator with every other, a feature intended to emulate the color sector physics of large- {N} matrix models. Considering out of equilibrium initial states, we analytically compute the time evolution of every correlator of the theory and of the entanglement entropies, allowing a proper discussion of global thermalization/scrambling of information through the entire system. Microscopic non-locality causes factorization of reduced density matrices, and entanglement just depends on the time evolution of occupation densities. In the second part of the article, we show how the gained intuition extends to large- {N} matrix models, where we provide a gauge invariant entanglement entropy for `generalized free fields', again depending solely on the quasinormal frequencies. The results challenge the fast scrambling conjecture and point to a natural scenario for the emergence of the so-called brick wall or stretched horizon. Finally, peculiarities of these models in regards to the thermodynamic limit and the information paradox are highlighted.
Agakishiev, G; Balanda, A; Belver, D; Belyaev, A; Berger-Chen, J C; Blanco, A; Böhmer, M; Boyard, J L; Cabanelas, P; Castro, E; Chernenko, S; Destefanis, M; Dohrmann, F; Dybczak, A; Epple, E; Fabbietti, L; Fateev, O; Finocchiaro, P; Fonte, P; Friese, J; Fröhlich, I; Galatyuk, T; Garzon, J A; Gernhäuser, R; Gilardi, C; Göbel, K; Golubeva, M; Gonzalez-Diaz, D; Guber, F; Gumberidze, M; Heinz, T; Hennino, T; Holzmann, R; Ierusalimov, A; Iori, I; Ivashkin, A; Jurkovic, M; Kämpfer, B; Karavicheva, T; Koenig, I; Koenig, W; Kolb, B W; Kornakov, G; Kotte, R; Krasa, A; Krizek, F; Krücken, R; Kuc, H; Kühn, W; Kugler, A; Kurepin, A; Ladygin, V; Lalik, R; Lange, J S; Lang, S; Lapidus, K; Lebedev, A; Liu, T; Lopes, L; Lorenz, M; Maier, L; Mangiarotti, A; Markert, J; Metag, V; Michalska, B; Michel, J; Moriniere, E; Mousa, J; Müntz, C; Münzer, R; Naumann, L; Pachmayer, Y C; Palka, M; Parpottas, Y; Pechenov, V; Pechenova, O; Pietraszko, J; Przygoda, W; Ramstein, B; Rehnisch, L; Reshetin, A; Rustamov, A; Sadovsky, A; Salabura, P; Scheib, T; Schmah, A; Schuldes, H; Schwab, E; Siebenson, J; Sobolev, Yu G; Spataro, S; Spruck, B; Ströbele, H; Stroth, J; Sturm, C; Tarantola, A; Teilab, K; Tlusty, P; Traxler, M; Trebacz, R; Tsertos, H; Vasiliev, T; Wagner, V; Weber, M; Wendisch, C; Wisniowski, M; Wüstenfeld, J; Yurevich, S; Zanevsky, Y
2015-01-01
The HADES data from p+Nb collisions at center of mass energy of $\\sqrt{s_{NN}}$= 3.2 GeV are analyzed by employing a statistical model. Accounting for the identified hadrons $\\pi^0$, $\\eta$, $\\Lambda$, $K^{0}_{s}$, $\\omega$ allows a surprisingly good description of their abundances with parameters $T_{chem}=(99\\pm11)$ MeV and $\\mu_{b}=(619\\pm34)$ MeV, which fits well in the chemical freeze-out systematics found in heavy-ion collisions. In supplement we reanalyze our previous HADES data from Ar+KCl collisions at $\\sqrt{s_{NN}}$= 2.6 GeV with an updated version of the statistical model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit. Special emphasis is put on feed-down contributions from higher-lying resonance states which have been proposed to explain the experimentally observed $\\Xi^-$ excess present in both data samples.
Parametric uncertainties in global model simulations of black carbon column mass concentration
Pearce, Hana; Lee, Lindsay; Reddington, Carly; Carslaw, Ken; Mann, Graham
2016-04-01
Previous studies have deduced that the annual mean direct radiative forcing from black carbon (BC) aerosol may regionally be up to 5 W m‑2 larger than expected due to underestimation of global atmospheric BC absorption in models. We have identified the magnitude and important sources of parametric uncertainty in simulations of BC column mass concentration from a global aerosol microphysics model (GLOMAP-Mode). A variance-based uncertainty analysis of 28 parameters has been performed, based on statistical emulators trained on model output from GLOMAP-Mode. This is the largest number of uncertain model parameters to be considered in a BC uncertainty analysis to date and covers primary aerosol emissions, microphysical processes and structural parameters related to the aerosol size distribution. We will present several recommendations for further research to improve the fidelity of simulated BC. In brief, we find that the standard deviation around the simulated mean annual BC column mass concentration varies globally between 2.5 x 10‑9 g cm‑2 in remote marine regions and 1.25 x 10‑6 g cm‑2 near emission sources due to parameter uncertainty Between 60 and 90% of the variance over source regions is due to uncertainty associated with primary BC emission fluxes, including biomass burning, fossil fuel and biofuel emissions. While the contributions to BC column uncertainty from microphysical processes, for example those related to dry and wet deposition, are increased over remote regions, we find that emissions still make an important contribution in these areas. It is likely, however, that the importance of structural model error, i.e. differences between models, is greater than parametric uncertainty. We have extended our analysis to emulate vertical BC profiles at several locations in the mid-Pacific Ocean and identify the parameters contributing to uncertainty in the vertical distribution of black carbon at these locations. We will present preliminary
Energy Technology Data Exchange (ETDEWEB)
Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology
1997-12-31
When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.
Probabilistic Analysis of Onion Routing in a Black-box Model
Feigenbaum, Joan; Syverson, Paul
2011-01-01
We perform a probabilistic analysis of onion routing. The analysis is presented in a black-box model of anonymous communication in the Universally Composable framework that abstracts the essential properties of onion routing in the presence of an active adversary that controls a portion of the network and knows all a priori distributions on user choices of destination. Our results quantify how much the adversary can gain in identifying users by exploiting knowledge of their probabilistic behavior. In particular, we show that, in the limit as the network gets large, a user u's anonymity is worst either when the other users always choose the destination u is least likely to visit or when the other users always choose the destination u chooses. This worst-case anonymity with an adversary that controls a fraction b of the routers is shown to be comparable to the best-case anonymity against an adversary that controls a fraction \\surdb.
Model system-based mechanistic studies of black tea thearubigin formation.
Yassin, Ghada H; Koek, Jan H; Kuhnert, Nikolai
2015-08-01
Thearubigins are the most abundant pigments found in black tea, comprising polyphenolic oxidation products, whose composition and chemical nature have remained unresolved until recently. In the course of studying the mechanism of thearubigin formation from green tea flavan-3-ols, a model system, based on electrochemical oxidation of one of the main tea flavan-3-ol substrates, epigallocatechin gallate (EGCG), was employed. Reaction intermediates and products were subsequently analysed using mass spectrometry techniques, allowing for the identification of key intermediates and products. The results provided, for the first time, spectroscopic evidence for the structures of primary oxidation products, and led to the conclusion that oxidation is mainly taking place on the B-ring and the galloyl group, where the oxidized components undergo oxidative coupling for the formation of theaflavins, theasinensins and polyhydroxylated flavan-3-ols, all precursors for thearubigin formation. Furthermore, density functional theory (DFT) calculations were carried out to support key findings.
Directory of Open Access Journals (Sweden)
A. I. Hienola
2013-04-01
Full Text Available The prediction skill of the regional aerosol–climate model REMO-HAM was assessed against the black carbon (BC concentration measurements from five locations in Finland, with focus on Hyytiälä station for the year 2005. We examined to what extent the model is able to reproduce the measurements using several statistical tools: median comparison, overlap coefficient (OVL; the common area under two probability distributions curves and Z score (a measure of standard deviation, shape and spread of the distributions. The results of the statistics showed that the model is biased low. The local and regional emissions of BC have a significant contribution, and the model tendency to flatten the observed BC is most likely dominated by the lack of domestic burning of biofuel in the emission inventories. A further examination of the precipitation data from both measurements and model showed that there is no correlation between REMO's excessive precipitation and BC underestimation. This suggests that the excessive wet removal is not the main cause of the low black carbon concentration output. In addition, a comparison of wind directions in relation with high black carbon concentrations shows that REMO-HAM is able to predict the BC source directions relatively well. Cumulative black carbon deposition fluxes over Finland were estimated, including the deposition on snow.
A new method of option pricing based on Black-Scholes model%基于Black-Scholes模型的期权定价新方法
Institute of Scientific and Technical Information of China (English)
沈玉波; 张待见; 宋立新
2011-01-01
考虑到实际金融市场的不完备性以及收益率分布的厚尾性,基于经典Black-Scholes模型并运用函数的下凸性,期权定价公式H（a）=E[（X-a）2]被推广为Hk（a）=E[（X-a）2k].通过DJSH（道琼斯上海）指数收益率的GARCH模型,并使用随机模拟的方法对这两个公式进行定价比较.结果表明这种方法有效提高了定价,从而降低了风险.%Actual financial markets are incompleted and distributions of yield rate are fat-tailed,so based on the classical Black-Scholes model and using downward convex property of function,option pricing formula H（a）=E[（X-a）2] is generalized to Hk（a）=E[（X-a）2k].With the GARCH model of DJSH rate and by using the method of stochastic simulation,effects of the two pricing formulas are compared.The results show that the new formula of option pricing effectively increases the price and reduces the risk.
Wave modelling south of the Danube Delta in the Black Sea
Rusu, Eugen; Butunoiu, Dorin
2015-04-01
A multilevel wave modelling system, based on SWAN (Simulating Waves Nearshore) spectral model, was implemented in the Black Sea and focused on the western coast. Model simulations have been performed for a 10-year time interval (1999-2008). Validations have been carried out against both satellite data and in situ measurements. A high resolution SWAN computational domain (100m x100m), which is focused on the coastal environment south of the Danube Delta, was also implemented. This coastal area includes Sacalin, which is a newly formed island in the Black Sea, south of the Saint George branch of the Danube. Initially, this was an island system, which consisted of two smaller islands, Greater Sacalin and Lesser Sacalin. In time, due to the enhanced sedimentary processes, the two islands merged into a single continuous landmass. The island has become the habitat of a great variety of rare species and for this reason it was declared an ecological reserve. In the high resolution computational domain, focused on the Sacalin Island, the effect of the currents induced by the Danube River outflow was also accounted in the model, together with some other processes specific to the coastal environment as diffraction, triad wave-wave interactions and wave induced set up. Considering the results of the ten-year SWAN model simulations with the modelling system covering the entire sea basin, the most relevant configurations of the environmental matrix, characteristic to this side of the sea, were defined. On this basis, by performing SWAN simulations in the high resolution coastal domain, the wave propagation patterns in the nearshore, together with some parameters related to the shoreline conditions, were evaluated. A great number of possible situations were analyzed. The most relevant correspond to different directions of the incoming waves (N, NE, E and SE, respectively) and significant wave energy conditions. The results provided by the modelling system indicate two different
Cuesta-Martínez, Carlos F; Mimica, Petar
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated GRBs, namely long lasting events characterized by the presence of a notable thermal component trailing the GRB prompt emission, and a rather weak traditional afterglow. GRB 101225A, the Christmas Burst (CB), is a prototype of such class. It has been suggested that BBD-GRBs could result from the merger of a binary system formed by a neutron star and the Helium core of a main sequence star. We have modeled the propagation of ultrarelativistic jets through the environment left behind the merger by means of detailed relativistic hydrodynamic numerical simulations. In this paper, the output of our numerical models is further postprocessed to obtain the (thermal) radiative signature of the resulting outflow. The complete (thermal and non-thermal) output of our models is considered in a companion contribution. Here, we outline the most relevant dynamical details of the jet propagation and connect them to the generation of thermal ra...
Krul, C.A.M.; Luiten-Schuite, A.; Tenfelde, A.; Ommen, B. van; Verhagen, H.; Havenaar, R.
2001-01-01
An in vitro gastrointestinal model, which simulates the conditions in the human digestive tract, was used to determine potential antimutagenic activity of extracts of black tea and green tea. In this paper, results are presented on the availability for absorption of potential antimutagenic compounds
Directory of Open Access Journals (Sweden)
Ambrish Gupta
2013-01-01
Full Text Available The main objectives of this paper are to incorporate modification in Black-Scholes option pricing model formula by adding some new variables on the basis of given assumption related to risk-free interest rate, and also shows the calculation process of new risk-free interest rate on the basis of modified variable. This paper also identifies the various situations in empirical testing of modified and original Black-Scholes formula with respect to the market value on the basis of assumed and calculated risk-free interest rate.
Ambrish Gupta; Matloob Ullah Khan; Sadaf Siraj
2013-01-01
The main objectives of this paper are to incorporate modification in Black-Scholes option pricing model formula by adding some new variables on the basis of given assumption related to risk-free interest rate, and also shows the calculation process of new risk-free interest rate on the basis of modified variable. This paper also identifies the various situations in empirical testing of modified and original Black-Scholes formula with respect to the market value on the basis of assumed and cal...
Philipson, W. R. (Principal Investigator); Hafker, W. R.
1980-01-01
The comparative value of manual versus digital image analysis for determining flood boundaries is being examined in a study of the use of LANDSAT data for modeling flooding of the Black River, in northern New York. The work is an extension of an earlier study in which Black River flooding was assessed through visually interpreted, multi-date LANDSAT band 7 images. Based on the results to date, it appears that neither color-additive viewing nor digital analysis of LANDSAT data provide improvement in accuracy over visual analysis of band 7 images, for delineating the boundaries of flood-affected areas.
Pedro, Alessandra Cristina; Granato, Daniel; Rosso, Neiva Deliberali
2016-01-15
This study was aimed the extraction of total flavonoids, anthocyanins and phenolics, as well as the antioxidant activity of black rice (Oryza sativa) and to study the stability in relation to pH, light and copigmentation. Variations in temperature (10-50°C), time (20-80min), and solid-solvent ratio (1:15-1:45) were studied using a Box-Behnken design. The regression models were significant (Pphytic and gallic acids in the optimized extract exposed to light displayed an intermolecular copigmentation. The main anthocyanin identified in black rice was cyanidin-3-glucoside. PMID:26258696
Polarized Proton Nucleus Scattering
Kopeliovich, B. Z.; Trueman, T. L.
2000-01-01
We show that, to a very good approximation, the ratio of the spin-flip to the non-flip parts of the elastic proton-nucleus amplitude is the same as for proton-nucleon scattering at very high energy. The result is used to do a realistic calculation of the analyzing power A_N for pC scattering in the Coulomb-nuclear interference (CNI) region of momentum transfer.
International Nuclear Information System (INIS)
The elastic and inelastic scattering of intermediate energy (less than or equal to 1 GeV) protons by nuclei is considered first. The discussion focuses on the determination of the proton-nucleus optical potential in terms of the elementary nucleon-nucleon scattering amplitudes and the properties of the target and residual nucleus. The result is a series of terms for the optical potential. Then the interaction of pions with nuclei for energies in the neighborhood of the Δ-resonance is discussed. In this energy domain an incident pion will with high probability be absorbed by a nucleon to produce the Δ-resonance and thus form a Δ-particle hole state in the nucleus. Next, the subject of hypernuclei is taken up. The Λ hypernuclei and a recently observed Σ hypernuclei comprise situations in which the core nucleus can be probed by a baryon of roughly the same mass as a nucleon, with similar albeit not identical interactions with nucleons. But the Λ (or Σ) does not need to satisfy the Pauli exclusion principle with respect to the nucleons, and therefore can be in orbits forbidden to it if it were a nucleon. As the energy of the projectile increases, it becomes correspondingly more important to take relativistic effects into account. The importance of these effects is strikingly revealed by experiments involving the collision of ultrarelativistic hadrons, protons, pions, kaons (up to Fermilab energies) with nuclei. This phenomenon forms part of the final topic, which includes as well as the collision of relativistic heavy ion projectiles with nuclei. A nuclear Weiszaecker-Williams method developed for dealing with peripheral collisions is described. 32 figures, 10 tables
Antinucleon-nucleus interactions
Energy Technology Data Exchange (ETDEWEB)
Dover, C.B.
1987-01-01
Recent experimental and theoretical results on anti p-nucleus interactions are reviewed. We focus on determinations of the anti p optical potential from elastic scattering, the use of (anti p, anti p') inelastic scattering to reveal aspects of the spin-isospin dependence of N anti N amplitudes, and some puzzling features of (anti p, anti n) charge exchange reactions on nuclei. 47 refs., 7 figs.
Black hole solutions to the F{sub 4}-model and their orbits (I)
Energy Technology Data Exchange (ETDEWEB)
Chemissany, W., E-mail: chemissany.wissam@gmail.com [Instituut voor Theoretische Fysica, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Giaccone, P.; Ruggeri, D.; Trigiante, M. [Laboratory of Theoretical Physics, Dipartimento di Scienze Applicate e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi, 24, I-10129 Torino (Italy)
2012-10-01
In this paper we continue the program of the classification of nilpotent orbits using the approach developed in (arXiv:1107.5986), within the study of black hole solutions in D=4 supergravities. Our goal in this work is to classify static, single center black hole solutions to a specific N=2 four-dimensional 'magic' model, with special Kaehler scalar manifold Sp(6,R)/U(3), as orbits of geodesics on the pseudo-quaternionic manifold F{sub 4(4)}/[SL(2,R) Multiplication-Sign Sp{sup Prime }(6,R)] with respect to the action of the isometry group F{sub 4(4)}. Our analysis amounts to the classification of the orbits of the geodesic 'velocity' vector with respect to the isotropy group H{sup Low-Asterisk }=SL(2,R) Multiplication-Sign Sp{sup Prime }(6,R), which include a thorough classification of the nilpotent orbits associated with extremal solutions and reveals a richer structure than the one predicted by the {beta}-{gamma}-labels alone, based on the Kostant-Sekiguchi approach. We provide a general proof of the conjecture made in (hep-th/0908.1742) which states that regular single center solutions belong to orbits with coinciding {beta}-{gamma}-labels. We also prove that the reverse is not true by finding distinct orbits with the same {beta}-{gamma}-labels, which are distinguished by suitably devised tensor classifiers. Only one of these is generated by regular solutions. Since regular static solutions only occur with nilpotent degree not exceeding 3, we only discuss representatives of these orbits in terms of black hole solutions. We prove that these representatives can be found in the form of a purely dilatonic four-charge solution (the generating solution in D=3) and this allows us to identify the orbit corresponding to the regular four-dimensional metrics. H{sup Low-Asterisk }-orbits with degree of nilpotency greater than 3 are analyzed solely from a group theoretical point of view, leaving a systematic analysis of their possible interpretation in
Sohrab, Siavash
2016-03-01
A scale-invariant model of statistical mechanics is applied to described modified forms of four laws of classical thermodynamics. Following de Broglie formula λrk = h /mkvrk , frequency of matter waves is defined as νrk = k /mkvrk leading to stochastic definitions of (Planck, Boltzmann) universal constants (h =mk c , k =mk c), λrkνrk = c , relating to spatiotemporal Casimir vacuum fluctuations. Invariant Mach number Maβ = v /vrβ is introduced leading to hierarchy of ``supersonic'' flow separated by shock front, viewed as ``event-horizon'' EHβ, from subsonic flow that terminates at surface of stagnant condensate of ``atoms'' defined as ``black-hole'' BHβ at scale β thus resulting in hierarchy of embedded ``black holes'' at molecular- atomic-, electron-, photon-, tachyon-. . . scales, ad infinitum. Classical black hole will correspond to solid phase photon or solid-light. It is argued that Bardeen-Carter-Hawking (1973) first law of black hole mechanics δM = (κ / 8 π) δA +ΩH δJ +ΦH δQ , instead of dE = TdS - PdV suggested by Bekenstein (1973), is analogous to first law of thermodynamics expressed as TdS = PdV + dE such that entropy of black hole, rather than to its horizon surface area, will be related to its total energy hence enthalpy H = TS leading to SBH = 4 kN in exact agreement with prediction of Major and Setter.
A thalamic input to the nucleus accumbens mediates opiate dependence.
Zhu, Yingjie; Wienecke, Carl F R; Nachtrab, Gregory; Chen, Xiaoke
2016-02-11
Chronic opiate use induces opiate dependence, which is characterized by extremely unpleasant physical and emotional feelings after drug use is terminated. Both the rewarding effects of a drug and the desire to avoid withdrawal symptoms motivate continued drug use, and the nucleus accumbens is important for orchestrating both processes. While multiple inputs to the nucleus accumbens regulate reward, little is known about the nucleus accumbens circuitry underlying withdrawal. Here we identify the paraventricular nucleus of the thalamus as a prominent input to the nucleus accumbens mediating the expression of opiate-withdrawal-induced physical signs and aversive memory. Activity in the paraventricular nucleus of the thalamus to nucleus accumbens pathway is necessary and sufficient to mediate behavioural aversion. Selectively silencing this pathway abolishes aversive symptoms in two different mouse models of opiate withdrawal. Chronic morphine exposure selectively potentiates excitatory transmission between the paraventricular nucleus of the thalamus and D2-receptor-expressing medium spiny neurons via synaptic insertion of GluA2-lacking AMPA receptors. Notably, in vivo optogenetic depotentiation restores normal transmission at these synapses and robustly suppresses morphine withdrawal symptoms. This links morphine-evoked pathway- and cell-type-specific plasticity in the paraventricular nucleus of the thalamus to nucleus accumbens circuit to opiate dependence, and suggests that reprogramming this circuit holds promise for treating opiate addiction.
Pion production at 1800 in nucleus-nucleus collisions
International Nuclear Information System (INIS)
A survey experiment of pion production at 1800 in nucleus-nucleus collisions is presented. Beams of 1.05 GeV/A and 2.1 GeV/A protons, alphas, and carbon were used, as well as proton beams of 0.80 GeV, 3.5 GeV, and 4.89 GeV, and argon beams of 1.05 GeV/A and 1.83 GeV/A. This is the first such experiment to use the heavier beams. Targets used ranged from carbon to lead. An in-depth review of the literature, both experimental and theoretical, is also presented. The systematics of the data are discussed, and comparisons are made both with prior experiments and with the predictions of the models reviewed. The cross sections appear consistent with a simple single nucleon-nucleon collision picture, without the need for collective or other exotic effects. Suggestions for future work are made
On Singularities and Black Holes in Combination-Driven Models of Technological Innovation Networks.
Solé, Ricard; Amor, Daniel R; Valverde, Sergi
2016-01-01
It has been suggested that innovations occur mainly by combination: the more inventions accumulate, the higher the probability that new inventions are obtained from previous designs. Additionally, it has been conjectured that the combinatorial nature of innovations naturally leads to a singularity: at some finite time, the number of innovations should diverge. Although these ideas are certainly appealing, no general models have been yet developed to test the conditions under which combinatorial technology should become explosive. Here we present a generalised model of technological evolution that takes into account two major properties: the number of previous technologies needed to create a novel one and how rapidly technology ages. Two different models of combinatorial growth are considered, involving different forms of ageing. When long-range memory is used and thus old inventions are available for novel innovations, singularities can emerge under some conditions with two phases separated by a critical boundary. If the ageing has a characteristic time scale, it is shown that no singularities will be observed. Instead, a "black hole" of old innovations appears and expands in time, making the rate of invention creation slow down into a linear regime.
Multivariate model of female black bear habitat use for a Geographic Information System
Clark, Joseph D.; Dunn, James E.; Smith, Kimberly G.
1993-01-01
Simple univariate statistical techniques may not adequately assess the multidimensional nature of habitats used by wildlife. Thus, we developed a multivariate method to model habitat-use potential using a set of female black bear (Ursus americanus) radio locations and habitat data consisting of forest cover type, elevation, slope, aspect, distance to roads, distance to streams, and forest cover type diversity score in the Ozark Mountains of Arkansas. The model is based on the Mahalanobis distance statistic coupled with Geographic Information System (GIS) technology. That statistic is a measure of dissimilarity and represents a standardized squared distance between a set of sample variates and an ideal based on the mean of variates associated with animal observations. Calculations were made with the GIS to produce a map containing Mahalanobis distance values within each cell on a 60- × 60-m grid. The model identified areas of high habitat use potential that could not otherwise be identified by independent perusal of any single map layer. This technique avoids many pitfalls that commonly affect typical multivariate analyses of habitat use and is a useful tool for habitat manipulation or mitigation to favor terrestrial vertebrates that use habitats on a landscape scale.
On Singularities and Black Holes in Combination-Driven Models of Technological Innovation Networks.
Solé, Ricard; Amor, Daniel R; Valverde, Sergi
2016-01-01
It has been suggested that innovations occur mainly by combination: the more inventions accumulate, the higher the probability that new inventions are obtained from previous designs. Additionally, it has been conjectured that the combinatorial nature of innovations naturally leads to a singularity: at some finite time, the number of innovations should diverge. Although these ideas are certainly appealing, no general models have been yet developed to test the conditions under which combinatorial technology should become explosive. Here we present a generalised model of technological evolution that takes into account two major properties: the number of previous technologies needed to create a novel one and how rapidly technology ages. Two different models of combinatorial growth are considered, involving different forms of ageing. When long-range memory is used and thus old inventions are available for novel innovations, singularities can emerge under some conditions with two phases separated by a critical boundary. If the ageing has a characteristic time scale, it is shown that no singularities will be observed. Instead, a "black hole" of old innovations appears and expands in time, making the rate of invention creation slow down into a linear regime. PMID:26821277
On Singularities and Black Holes in Combination-Driven Models of Technological Innovation Networks.
Directory of Open Access Journals (Sweden)
Ricard Solé
Full Text Available It has been suggested that innovations occur mainly by combination: the more inventions accumulate, the higher the probability that new inventions are obtained from previous designs. Additionally, it has been conjectured that the combinatorial nature of innovations naturally leads to a singularity: at some finite time, the number of innovations should diverge. Although these ideas are certainly appealing, no general models have been yet developed to test the conditions under which combinatorial technology should become explosive. Here we present a generalised model of technological evolution that takes into account two major properties: the number of previous technologies needed to create a novel one and how rapidly technology ages. Two different models of combinatorial growth are considered, involving different forms of ageing. When long-range memory is used and thus old inventions are available for novel innovations, singularities can emerge under some conditions with two phases separated by a critical boundary. If the ageing has a characteristic time scale, it is shown that no singularities will be observed. Instead, a "black hole" of old innovations appears and expands in time, making the rate of invention creation slow down into a linear regime.
Analysing black phosphorus transistors using an analytic Schottky barrier MOSFET model.
Penumatcha, Ashish V; Salazar, Ramon B; Appenzeller, Joerg
2015-01-01
Owing to the difficulties associated with substitutional doping of low-dimensional nanomaterials, most field-effect transistors built from carbon nanotubes, two-dimensional crystals and other low-dimensional channels are Schottky barrier MOSFETs (metal-oxide-semiconductor field-effect transistors). The transmission through a Schottky barrier-MOSFET is dominated by the gate-dependent transmission through the Schottky barriers at the metal-to-channel interfaces. This makes the use of conventional transistor models highly inappropriate and has lead researchers in the past frequently to extract incorrect intrinsic properties, for example, mobility, for many novel nanomaterials. Here we propose a simple modelling approach to quantitatively describe the transfer characteristics of Schottky barrier-MOSFETs from ultra-thin body materials accurately in the device off-state. In particular, after validating the model through the analysis of a set of ultra-thin silicon field-effect transistor data, we have successfully applied our approach to extract Schottky barrier heights for electrons and holes in black phosphorus devices for a large range of body thicknesses. PMID:26563458
Directory of Open Access Journals (Sweden)
Z. Varga
2007-09-01
experiments. In most cases good agreement was found. For modelling purposes S_{c} vs. d_{dry} plots are given and the dependence of water activity and surface tension on concentration are also formulated.
Institute of Scientific and Technical Information of China (English)
薛红; 聂赞坎
2000-01-01
本文提出具有变系数和红利的多维Black-Scholes模型,利用倒向随机微分方程和鞅方法, 得到欧式未定权益的一般定价公式及套期保值策略.在具体金融市场,给出欧式期权的定价公式和套期保值策略,以及美式看涨期权价格的界.%For discussing the arbitrage-free pricing of European contingent claim, this paper proposes multi-dimensional Black-Scho les model with non-constant coefficients and the underlying stocks pay dividends . By means of backward stochastic different equation and martingale methods, we obtain general pricing formula and hedging strategy of European contingent claim . In the particular financial market, the pricing formula and hedging strategy o f European option and bounds of the price on American call option are also consi dered.
Mashnik, S. G.; Gudima, K. K.; Prael, R. E.; Sierk, A. J.
2003-01-01
The LAQGSM code has been recently developed at Los Alamos National Laboratory to simulate nuclear reactions for proton radiography applications. We have benchmarked our code against most available measured data both for proton-nucleus and nucleus-nucleus interactions at incident energies from 10 MeV to 800 GeV and have compared our results with predictions of other current models used by the nuclear community. Here, we present a brief description of our code and show illustrative results obta...
Energy Technology Data Exchange (ETDEWEB)
Mahmood, R.; Von Salzen, Knut; Flanner, M. G.; Sand, M.; Langner, J.; Wang, Hailong; Huang, L.
2016-06-22
This study quantifies black carbon (BC) processes in three global climate models and one chemistry transport model, with focus on the seasonality of BC transport, emissions, wet and dry deposition in the Arctic. In the models, transport of BC to the Arctic from lower latitudes is the major BC source for this region while Arctic emissions are very small. All models simulated a similar annual cycle of BC transport from lower latitudes to the Arctic, with maximum transport occurring in July. Substantial differences were found in simulated BC burdens and vertical distributions, with CanAM (NorESM) producing the strongest (weakest) seasonal cycle. CanAM also has the shortest annual mean residence time for BC in the Arctic followed by SMHI-MATCH, CESM and NorESM. The relative contribution of wet and dry deposition rates in removing BC varies seasonally and is one of the major factors causing seasonal variations in BC burdens in the Arctic. Overall, considerable differences in wet deposition efficiencies in the models exist and are a leading cause of differences in simulated BC burdens. Results from model sensitivity experiments indicate that scavenging of BC in convective clouds acts to substantially increase the overall efficiency of BC wet deposition in the Arctic, which leads to low BC burdens and a more pronounced seasonal cycle compared to simulations without convective BC scavenging. In contrast, the simulated seasonality of BC concentrations in the upper troposphere is only weakly influenced by wet deposition in stratiform (layer) clouds whereas lower tropospheric concentrations are highly sensitive.
Callahan, Joshua W; Abercrombie, Elizabeth D
2015-06-01
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that results in motor, cognitive and psychiatric abnormalities. Dysfunction in neuronal processing between the cortex and the basal ganglia is fundamental to the onset and progression of the HD phenotype. The corticosubthalamic hyperdirect pathway plays a crucial role in motor selection and blockade of neuronal activity in the subthalamic nucleus (STN) results in hyperkinetic movement abnormalities, similar to the motor symptoms associated with HD. The aim of the present study was to examine whether changes in the fidelity of information transmission between the cortex and the STN emerge as a function of phenotypic severity in the YAC128 mouse model of HD. We obtained in vivo extracellular recordings in the STN and concomitant electrocorticogram (ECoG) recordings during discrete brain states that reflected global cortical network synchronization or desynchronization. At early ages in YAC128 mice, both the cortex and the STN exhibited patterns of hyperexcitability. As symptom severity progressed, cortical entrainment of STN activity was disrupted and there was an increase in the proportion of non-oscillating, tonically firing STN neurons that were less phase-locked to cortical activity. Concomitant to the dissipation of STN entrainment, there was a reduction in the evoked response of STN neurons to focal cortical stimulation. The spontaneous discharge of STN neurons in YAC128 mice also decreased with age and symptom severity. These results indicate dysfunction in the flow of information within the corticosubthalamic circuit and demonstrate progressive age-related disconnection of the hyperdirect pathway in a transgenic mouse model of HD.
Institute of Scientific and Technical Information of China (English)
林汉燕; 邓国和
2011-01-01
在分数次Black—Scholes模型下，以连续支付红利的美式看涨期权为例，用二次近似法推导美式期权定价的近似公式，得到了与经典Black-Scholes模型下相似的结果．最后证明美式看涨一看跌期权的对称关系在分数次Black-Scholes模型下也成立．%Based on the assumption of the fractional Black-Scholes model, a quadratic approximation under the Black-Scholes model is applied to pricing the American call option with continuous-paying divi- dend, a similar approximate formula is derived, and the call-put symmetric relation is proved.
Modeling Malignant Breast Cancer Occurrence and Survival in Black and White Women
Gleason, Michael
2013-01-01
Background: Breast cancer (BC), the most common cancer diagnosed in women in the United States, is a heterogeneous disease in which age-specific incidence rates (ASIRs) differ by race and mortality rates are higher in blacks than whites. Goals: (i) understand the reasons for the black-to-white ethnic crossover in the ASIRs; (ii) formulate a…
The value of "black-box" neural network modeling in subsurface flow prediction
Paleologos, E.; Skitzi, I.; Katsifarakis, K.
2012-04-01
In several hydrologic cases the complexity of the processes involved tied in with the uncertainty in the subsurface geologic environment, geometries, and boundary conditions cannot be addressed by constitutive relationships, either in a deterministic or a stochastic framework. "Black-box" models are used routinely in surface hydrologic predictions, but in subsurface hydrology there is still a tendency to rely on physical descriptions, even in problems where the geometry, the medium, the processes, the boundary conditions are largely unknown. Subsurface flow in karstic environments exemplifies all the above complexities and uncertainties rendering the use of physical models impractical. The current study uses neural networks to exemplify that "black-box" models can provide useful predictions even in the absence of physical process descriptions. Daily discharges of two springs lying in a karstic environment were simulated for a period of two and a half years with the use of a multi-layer perceptron back-propagation neural network. Missing discharge values were supplemented by assuming linear relationships during base flow conditions, thus extending the length of the data record during the network's training phase and improving its performance. The time lag between precipitation and spring discharge differed significantly for the two springs indicating that in karstic environments hydraulic behavior is dominated, even within a few hundred meters, by local conditions. Optimum training results were attained with a Levenberg-Marquardt algorithm resulting in a network architecture consisting of two input layer neurons, four hidden layer neurons, and one output layer neuron, the spring's discharge. The neural network's predictions captured the behavior for both springs and followed very closely the discontinuities in the discharge time series. Under/over-estimation of observed discharges for the two springs remained below 3%, with the exception of a few local maxima where
Raja, Ammar
2009-01-01
Options are historically being priced using Black Scholes option pricing model and one of the prominent features of it is normal distribution. In this research paper I will calculate European call options using log logistic distribution instead of normal distribution. My argument is that a model with logistic distribution reflects better fit of option prices as compared to normal distribution. In this research paper I have used historic data on stocks, value European call options using both ...
Babak, Stanislav; Buonanno, Alessandra
2016-01-01
In Ref. [1], the properties of the first gravitational wave detected by LIGO, GW150914, were measured by employing an effective-one-body (EOB) model of precessing binary black holes whose underlying dynamics and waveforms were calibrated to numerical-relativity (NR) simulations. Here, we perform the first extensive comparison of such EOBNR model to 70 precessing NR waveforms that span mass ratios from 1 to 5, dimensionless spin magnitudes up to 0.5, generic spin orientations, and length of about 20 orbits. We work in the observer's inertial frame and include all $\\ell=2$ modes in the gravitational-wave polarizations. We introduce new prescriptions for the EOB ringdown signal concerning its spectrum and time of onset. For total masses between 10Msun and 200Msun, we find that precessing EOBNR waveforms have unfaithfulness within about 3% to NR waveforms when considering the Advanced-LIGO design noise curve. This result is obtained without recalibration of the inspiral-plunge of the underlying nonprecessing EOBN...
Statistical modeling of the fluid dual to Boulware-Deser black hole
López, J. L.; Bhattacharya, Swastik; Shankaranarayanan, S.
2016-07-01
In this work we study the statistical and thermodynamic properties of the horizon fluid corresponding to the Boulware-Deser (BD) black hole of Einstein-Gauss-Bonnet gravity. Using mean field theory, we show explicitly that the BD fluid exhibits the coexistence of two phases, a BEC (Bose Einstein Condensate) and a noncondensed phase corresponding to the Einstein term and the Gauss-Bonnet term in the gravity action, respectively. In the fluid description, the high-energy corrections associated to Gauss-Bonnet gravity are modeled as excitations of the fluid medium. We provide statistical modeling of the excited part of the fluid and explicitly show that it is characterized by a generalized dispersion relation which in D =6 dimensions corresponds to a nonrelativistic fluid. We also shed light on the ambiguity found in the literature regarding the expression of the entropy of the horizon fluid. We provide a general prescription to obtain the entropy and show that it is indeed given by Wald entropy.
Energy Technology Data Exchange (ETDEWEB)
Gallagher, H.; /Tufts U.; Garvey, G.; /Los Alamos; Zeller, G.P.; /Fermilab
2011-01-01
The study of neutrino oscillations has necessitated a new generation of neutrino experiments that are exploring neutrino-nuclear scattering processes. We focus in particular on charged-current quasi-elastic scattering, a particularly important channel that has been extensively investigated both in the bubble-chamber era and by current experiments. Recent results have led to theoretical reexamination of this process. We review the standard picture of quasi-elastic scattering as developed in electron scattering, review and discuss experimental results, and discuss additional nuclear effects such as exchange currents and short-range correlations that may play a significant role in neutrino-nucleus scattering.
Antineutron-nucleus annihilation
Botta, E
2001-01-01
The n-nucleus annihilation process has been studied by the OBELIX experiment at the CERN Low Energy Antiproton Ring (LEAR) in the (50-400) MeV/c projectile momentum range on C, Al, Cu, Ag, Sn, and Pb nuclear targets. A systematic survey of the annihilation cross- section, sigma /sub alpha /(A, p/sub n/), has been performed, obtaining information on its dependence on the target mass number and on the incoming n momentum. For the first time the mass number dependence of the (inclusive) final state composition of the process has been analyzed. Production of the rho vector meson has also been examined. (13 refs).
Karamintziou, Sofia D.; Deligiannis, Nick G.; Piallat, Brigitte; Polosan, Mircea; Chabardès, Stephan; David, Olivier; Stathis, Pantelis G.; Tagaris, George A.; Boviatsis, Efstathios J.; Sakas, Damianos E.; Polychronaki, Georgia E.; Tsirogiannis, George L.; Nikita, Konstantina S.
2016-02-01
Objective. Almost 30 years after the start of the modern era of deep brain stimulation (DBS), the subthalamic nucleus (STN) still constitutes a standard stimulation target for advanced Parkinson’s disease (PD), but the use of STN-DBS is also now supported by level I clinical evidence for treatment-refractory obsessive-compulsive disorder (OCD). Disruption of neural synchronization in the STN has been suggested as one of the possible mechanisms of action of standard and alternative patterns of STN-DBS at a local level. Meanwhile, recent experimental and computational modeling evidence has signified the efficiency of alternative patterns of stimulation; however, no indications exist for treatment-refractory OCD. Here, we comparatively simulate the desynchronizing effect of standard (regular at 130 Hz) versus temporally alternative (in terms of frequency, temporal variability and the existence of bursts or pauses) patterns of STN-DBS for PD and OCD, by means of a stochastic dynamical model and two microelectrode recording (MER) datasets. Approach. The stochastic model is fitted to subthalamic MERs acquired during eight surgical interventions for PD and eight surgical interventions for OCD. For each dynamical system simulated, we comparatively assess the invariant density (steady-state phase distribution) as a measure inversely related to the desynchronizing effect yielded by the applied patterns of stimulation. Main results. We demonstrate that high (130 Hz)—and low (80 Hz)—frequency irregular patterns of stimulation, and low-frequency periodic stimulation interrupted by bursts of pulses, yield in both pathologic conditions a significantly stronger desynchronizing effect compared with standard STN-DBS, and distinct alternative patterns of stimulation. In PD, values of the invariant density measure are proven to be optimal at the dorsolateral oscillatory region of the STN including sites with the optimal therapeutic window. Significance. In addition to providing
Nucleus-nucleus potential with shell-correction contribution
Denisov, V Yu
2015-01-01
The full relaxed-density potential between spherical nuclei is considered as a sum of the macroscopic and shell-correction contributions. The macroscopic part of the potential is related to a nucleus-nucleus potential obtained in the framework of the extended Thomas-Fermi approach with the Skyrme and Coulomb forces and the relaxed-density ansatz for evaluation of proton and neutron densities of interacting nuclei. A simple prescription for the shell-correction part of the total potential is discussed. The parameters of the shell-correction and macroscopic parts of the relaxed-density potential are found by fitting the empirical barrier heights of the 89 nucleus-nucleus systems as well as macroscopic potentials evaluated for 1485 nucleus-nucleus systems at 12 distances around touching points.
Li, Yu-Chun; He, Xiao-Tao
2016-07-01
Experimentally observed ground state band based on the 1/2-[521] Nilsson state and the first exited band based on the 7/2-[514] Nilsson state of the odd- Z nucleus 255Lr are studied by the cranked shell model (CSM) with the paring correlations treated by the particle-number-conserving (PNC) method. This is the first time the detailed theoretical investigations are performed on these rotational bands. Both experimental kinematic and dynamic moments of inertia ( J (1) and J (2)) versus rotational frequency are reproduced quite well by the PNC-CSM calculations. By comparing the theoretical kinematic moment of inertia J (1) with the experimental ones extracted from different spin assignments, the spin 17/2- → 13/2- is assigned to the lowest-lying 196.6(5) keV transition of the 1/2-[521] band, and 15/2- → 11/2- to the 189(1) keV transition of the 7/2-[514] band, respectively. The proton N = 7 major shell is included in the calculations. The intruder of the high- j low-Ω 1 j 15/2 (1/2-[770]) orbital at the high spin leads to band-crossings at ħω ≈ 0.20 ( ħω ≈ 0.25) MeV for the 7/2-[514] α = -1/2 ( α = +1/2) band, and at ħω ≈ 0.175 MeV for the 1/2-[521] α = -1/2 band, respectively. Further investigations show that the band-crossing frequencies are quadrupole deformation dependent.
Directory of Open Access Journals (Sweden)
Igor eSpigelman
2012-06-01
Full Text Available Chronic alcohol exposure causes marked changes in reinforcement mechanisms and motivational state that are thought to contribute to the development of cravings and relapse during protracted withdrawal. The nucleus accumbens (NAcc is a key structure of the mesolimbic dopaminergic reward system. Although the NAcc plays an important role in mediating alcohol-seeking behaviors, little is known about the molecular mechanisms underlying alcohol-induced neuroadaptive changes in NAcc function. The aim of this study was to investigate the effects of chronic intermittent ethanol (CIE treatment, a rat model of alcohol withdrawal and dependence, on intrinsic electrical membrane properties and glutamatergic synaptic transmission of medium spiny neurons (MSNs in the NAcc core during protracted withdrawal. We show that CIE treatment followed by prolonged withdrawal increased the inward rectification of MSNs observed at hyperpolarized potentials. In addition, MSNs from CIE-treated animals displayed a lower input resistance, faster action potentials (APs and larger fast afterhyperpolarizations (fAHPs than MSNs from vehicle-treated animals, all suggestive of increases in K+-channel conductances. Significant increases in the Cs+-sensitive inwardly-rectifying K+-current accounted for the increased input resistance, while increases in the A-type K+-current accounted for the faster APs and increased fAHPs in MSNs from CIE rats. We also show that the amplitude and the conductance of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR-mediated mEPSCs were enhanced in CIE-treated animals due to an increase in a small fraction of functional postsynaptic GluA2-lacking AMPARs. These long-lasting modifications of excitability and excitatory synaptic receptor function of MSNs in the NAcc core could play a critical role in the neuroadaptive changes underlying alcohol withdrawal and dependence.
Chopra, Sahila; Kaur, Arshdeep; Gupta, Raj K.
2015-03-01
After a successful attempt to define and determine recently the compound nucleus (CN) fusion/ formation probability PCN within the dynamical cluster-decay model (DCM), we introduce and estimate here for the first time the survival probability Psurv of CN against fission, again within the DCM. Calculated as the dynamical fragmentation process, Psurv is defined as the ratio of the evaporation residue (ER) cross section σER and the sum of σER and fusion-fission (ff) cross section σff, the CN formation cross section σCN, where each contributing fragmentation cross section is determined in terms of its formation and barrier penetration probabilities P0 and P . In DCM, the deformations up to hexadecapole and "compact" orientations for both in-plane (coplanar) and out-of-plane (noncoplanar) configurations are allowed. Some 16 "hot" fusion reactions, forming a CN of mass number ACN˜100 to superheavy nuclei, are analyzed for various different nuclear interaction potentials, and the variation of Psurv on CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 is investigated. Interesting results are that three groups, namely, weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, are identified with Psurv, respectively, ˜1 ,˜10-6 , and ˜10-10 . For the weakly fissioning group (100 PCN belongs to the strongly fissioning superheavy group, Psurv belongs to weakly fissioning nuclei; for Pt* isotopes, the inverse of all the compound systems studied, both PCN and Psurv decrease with the increase of E*; for 213 ,215 ,217Fr* nuclei, though fissility χ is nearly the same, Psurv for 213 ,217Fr* is of the same order as for weakly fissioning nuclei, but that for 215Fr* is of the order of radioactive nuclei. Apparently, further calculations are called for.
Higgs-Boson Production in Nucleus-Nucleus Collisions
Norbury, John W.
1992-01-01
Cross section calculations are presented for the production of intermediate-mass Higgs bosons produced in ultrarelativistic nucleus-nucleus collisions via two photon fusion. The calculations are performed in position space using Baur's method for folding together the Weizsacker-Williams virtual-photon spectra of the two colliding nuclei. It is found that two photon fusion in nucleus-nucleus collisions is a plausible way of finding intermediate-mass Higgs bosons at the Superconducting Super Collider or the CERN Large Hadron Collider.
Stress-energy tensor in soluble models of spherically symmetric charged black hole evaporation
International Nuclear Information System (INIS)
We study the decay of a near-extremal black hole in AdS2, related to the near-horizon region of (3+1)-dimensional Reissner-Nordstroem spacetime, following Fabbri, Navarro, and Navarro-Salas. Back reaction is included in a semiclassical approximation. Calculations of the stress-energy tensor of matter coupled to the physical spacetime for an affine null observer demonstrate that the black hole evaporation proceeds smoothly and the near-extremal black hole evolves back to an extremal ground state, until this approximation breaks down
Institute of Scientific and Technical Information of China (English)
贾丽君
2012-01-01
在传统Black-Scholes期权定价模型的基础上,进一步考虑随机利率模型.根据一个自治常微分方程的解的存在性结果,利用上下解方法得到随机利率模型下Black-Scholes方程的Dirichlet问题的解存在的一个条件.%Based on the classical Black-Scholes option pricing model,this paper further considers the stochastic interest rate case. According to the result about the existence of the solution of an autonomy ordinary differential equation,we obtain an existence condition for the solution of the Black-Scholes Dirichlet problem with stochastic interest rate using sub-supsolution method.
van der Marel, Roeland
2011-10-01
Studies of the dynamics and stellar populations of globular clusters are at the forefront of HST research. These two topics are deeply intertwined. Clusters experience an interplay of collisional processes that drive stars toward energy equipartition, thus segregating more massive stars to the core. In young clusters, this can even lead to the formation of intermediate-mass black holes {IMBHs}, which are of great astrophysical interest, although evidence for them continues to be disputed. Our recent HST{-supported} observational and theoretical studies indicate that equipartition in a cluster is not generally attained. Measurement of the actual mass segregation in clusters can yield significant insight into some of the most important cluster parameters, including the mass of any IMBH {which tends to quench mass segregation}. We have demonstrated this explictly on archival data of NGC2298 and M10. HST imaging {including parallel fields} exists in fact over large radial ranges for many globular clusters. This trove of information remains largely untapped, as studies generally focus on the cluster core. We propose here to rigorously quantify and model the mass segregation in all 66 Galactic globular clusters with suitable HST data. We will create CMDs, LFs, and MFs as function of radius, and will release the resulting Legacy data products to the community to enable a host of ancillary investigations. We will run N-body models to interpret the observed mass segregation in the sample clusters. Data-model comparisons will constrain the mass of any IMBHs, will identify IMBH-candidates for more targeted follow-up, and will shed new light on cluster structure and evolution.
Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea
Directory of Open Access Journals (Sweden)
Nikolaos Kokkos
2016-04-01
Full Text Available A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively. Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island, depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1, tending to destroy surface meso-scale eddies.
Comparisons of eccentric binary black hole simulations with post-Newtonian models
Hinder, Ian; Laguna, Pablo; Shoemaker, Deirdre
2008-01-01
We present the first comparison between numerical relativity (NR) simulations of an eccentric binary black hole system with corresponding post-Newtonian (PN) results. We evolve an equal-mass, non-spinning configuration with an initial eccentricity e = 0.1 for 21 gravitational wave cycles before merger, and find agreement in the gravitational wave phase with an adiabatic eccentric PN model with 2 PN radiation reaction within 0.1 radians for 8 cycles. The NR and PN phase difference grows to 0.8 radians by 5 cycles before merger. We find that these results can be obtained by expanding the eccentric PN expressions in terms of the frequency-related variable x = (omega M)^{2/3} with M the total mass of the binary. When using instead the mean motion n = 2 pi/P, where P is the orbital period, the comparison leads to significant disagreements with NR. We also introduce a new method for matching NR and PN waveforms, based on extrapolating parameters determined from least squares fitting as t -> -infinity.
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.
Paolo, C.; Gandhi, N.; Bhavsar, S.; Heuvel-Greve, van den M.J.; Koelmans, A.A.
2010-01-01
Bioavailability and bioaccumulation of polybrominated diphenylethers (PBDEs) are affected by adsorption on black carbon (BC) and metabolism in biota, respectively. Recent studies have addressed these two processes separately, illustrating their importance in assessing contaminant dynamics. In order
Black hole production and graviton emission in models with large extra dimensions
Energy Technology Data Exchange (ETDEWEB)
Koch, B.
2007-11-21
This thesis studies the possible production of microscopical black holes and the emission of graviational radiation under the assumption of large extra dimensions. We derive observables for the Large Hadron Collider and for ultra high energetic cosmic rays. (orig.)
Black hole production and graviton emission in models with large extra dimensions
International Nuclear Information System (INIS)
This thesis studies the possible production of microscopical black holes and the emission of graviational radiation under the assumption of large extra dimensions. We derive observables for the Large Hadron Collider and for ultra high energetic cosmic rays. (orig.)
Intermediate-mass-ratio black hole binaries II: Modeling Trajectories and Gravitational Waveforms
Nakano, Hiroyuki; Lousto, Carlos O; Campanelli, Manuela
2011-01-01
We revisit the scenario of small-mass-ratio (q) black-hole binaries; performing new, more accurate, simulations of mass ratios 10:1 and 100:1 for initially nonspinning black holes. We propose fitting functions for the trajectories of the two black holes as a function of time and mass ratio (in the range 1/100 < q < 1/10$) that combine aspects of post-Newtonian trajectories at smaller orbital frequencies and plunging geodesics at larger frequencies. We then use these trajectories to compute waveforms via black hole perturbation theory. Using the advanced LIGO noise curve, we see a match of ~99.5% for the leading (l,m)=(2,2) mode between the numerical relativity and perturbative waveforms. Nonleading modes have similarly high matches. We thus prove the feasibility of efficiently generating a bank of gravitational waveforms in the intermediate-mass-ratio regime using only a sparse set of full numerical simulations.
Intermediate-mass-ratio black hole binaries. II. Modeling trajectories and gravitational waveforms
Nakano, Hiroyuki; Zlochower, Yosef; Lousto, Carlos O.; Campanelli, Manuela
2011-12-01
We revisit the scenario of small-mass-ratio (q) black hole binaries; performing new, more accurate, simulations of mass ratios 10:1 and 100:1 for initially nonspinning black holes. We propose fitting functions for the trajectories of the two black holes as a function of time and mass ratio (in the range 1/100≤q≤1/10) that combine aspects of post-Newtonian trajectories at smaller orbital frequencies and plunging geodesics at larger frequencies. We then use these trajectories to compute waveforms via black hole perturbation theory. Using the advanced LIGO noise curve, we see a match of ˜99.5% for the leading (ℓ,m)=(2,2) mode between the numerical relativity and perturbative waveforms. Nonleading modes have similarly high matches. We thus prove the feasibility of efficiently generating a bank of gravitational waveforms in the intermediate-mass-ratio regime using only a sparse set of full numerical simulations.
Energy Technology Data Exchange (ETDEWEB)
Grace, T.M.; Frederick, W.J.; Salcudean, M.; Wessel, R.A.
1998-08-01
This project was initiated in October 1990, with the objective of developing and validating a new computer model of a recovery boiler furnace using a computational fluid dynamics (CFD) code specifically tailored to the requirements for solving recovery boiler flows, and using improved submodels for black liquor combustion based on continued laboratory fundamental studies. The key tasks to be accomplished were as follows: (1) Complete the development of enhanced furnace models that have the capability to accurately predict carryover, emissions behavior, dust concentrations, gas temperatures, and wall heat fluxes. (2) Validate the enhanced furnace models, so that users can have confidence in the predicted results. (3) Obtain fundamental information on aerosol formation, deposition, and hardening so as to develop the knowledge base needed to relate furnace model outputs to plugging and fouling in the convective sections of the boiler. (4) Facilitate the transfer of codes, black liquid submodels, and fundamental knowledge to the US kraft pulp industry. Volume 2 contains the last section of Appendix I, Radiative heat transfer in kraft recovery boilers, and the first section of Appendix II, The effect of temperature and residence time on the distribution of carbon, sulfur, and nitrogen between gaseous and condensed phase products from low temperature pyrolysis of kraft black liquor.
Mental Accounting: A Closed-Form Alternative to the Black Scholes Model
Siddiqi, Hammad
2013-01-01
The principle of no arbitrage says that identical assets should offer the same returns. However, experimental and anecdotal evidence suggests that people often rely on analogy making while valuing assets. The principle of analogy making says that similar assets should offer the same returns. I show that the principle of analogy making generates a closed-form alternative to the Black Scholes formula that does not require a complete market. The new formula differs from the Black Scholes formula...
Antibaryon-nucleus bound states
Hrtánková, J
2014-01-01
We calculated antibaryon ($\\bar{B}$ = $\\bar{p}$, $\\bar{\\Lambda}$, $\\bar{\\Sigma}$, $\\bar{\\Xi}$) bound states in selected nuclei within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{B}$-meson coupling constants were scaled to yield corresponding potentials consistent with available experimental data. Large polarization of the nuclear core caused by $\\bar{B}$ was confirmed. The $\\bar{p}$ annihilation in the nuclear medium was incorporated by including a phenomenological imaginary part of the optical potential. The calculations using a complex $\\bar{p}$-nucleus potential were performed fully self-consistently. The $\\bar{p}$ widths significantly decrease when the phase space reduction is considered for $\\bar{p}$ annihilation products, but they still remain sizeable for potentials consistent with $\\bar{p}$-atom data.
Institute of Scientific and Technical Information of China (English)
Chao Zhang; Wen-Han Hu; De-Long Wu; Kai Zhang; Jian-Guo Zhang
2015-01-01
Background:Recent clinical and preclinical studies have suggested that deep brain stimulation (DBS) can be used as a tool to enhance cognitive functions.The aim of the present study was to investigate the impact of DBS at three separate targets in the Papez circuit,including the anterior nucleus of thalamus (ANT),the entorhinal cortex (EC),and the fornix (FX),on cognitive behaviors in an Alzheimer's disease (AD) rat model.Methods:Forty-eight rats were subjected to an intrahippocampal injection ofamyloid peptides 1-42 to induce an AD model.Rats were divided into six groups:DBS and sham DBS groups of ANT,EC,and FX.Spatial learning and memory were assessed by the Morris water maze (MWM).Recognition memory was investigated by the novel object recognition memory test (NORM).Locomotor and anxiety-related behaviors were detected by the open field test (OF).By using two-way analysis of variance (ANOVA),behavior differences between the six groups were analyzed.Results:In the MWM,the ANT,EC,and FX DBS groups performed differently in terms of the time spent in the platform zone (F(2.23) =6.04,P ＜ 0.01),the frequency of platform crossing (F(2,23) =11.53,P ＜ 0.001),and the percent time spent within the platform quadrant (F(2,23) =6.29,P ＜ 0.01).In the NORM,the EC and FX DBS groups spent more time with the novel object,although the ANT DBS group did not (F(2,23) =10.03,P ＜ 0.001).In the OF,all of the groups showed a similar total distance moved (F(1.42) =1.14,P =0.29)and relative time spent in the center (F(2,42) =0.56,P =0.58).Conclusions:Our results demonstrated that DBS of the EC and FX facilitated hippocampus-dependent spatial memory more prominently thanANT DBS.In addition,hippocampus-independent recognition memory was enhanced by EC and FX DBS.None of the targets showed side-effects of anxiety or locomotor behaviors.
International Nuclear Information System (INIS)
It is now widely accepted that most of normal galaxies have their central supermassive black holes (SMBHs). However, the formation and evolution of SMBHs is still open question and a hot topic in astrophysics. In this article, we review recent theoretical studies on the formation of SMBHs in the center of galaxies, and mention the importance of constructing a multi-scale theoretical model. (author)
Modeling the impact of black carbon on snowpack properties at an high altitude site in the Himalayas
Jacobi, Hans-Werner; Ménégoz, Martin; Gallée, Hubert; Lim, Saehee; Zanatta, Marco; Jaffrezo, Jean-Luc; Cozic, Julie; Laj, Paolo; Bonasoni, Paolo; Cristofanelli, Paolo; Stocchi, Paolo; Marinoni, Angela; Verza, Gianpietro; Vuillermoz, Elisa
2013-04-01
Light absorbing aerosols in the snow can modify the snow albedo. As a result, the seasonal snowpack can melt earlier compared to the unaffected snow leading to a warming effect on the atmosphere. Several global model studies have indicated that the long-range transport of light absorbing aerosols into the Himalayas and the subsequent deposition to the snow have contributed to a temperature rise in these regions. Due to its strong light absorbing properties, black carbon (BC) may play an important role in this process. To evaluate the possible impact of BC on snow albedo we determined BC concentrations in a range of fresh and older snow samples collected between 2009 and 2012 in the vicinity of the Pyramid station, Nepal at an altitude of more than 5000 m. BC concentrations in the snow were obtained after nebulizing the melted samples using a single particle soot photometer. The observed seasonal cycle in BC concentrations in the snow corresponds to observed seasonal cycles in atmospheric BC detected at the Pyramid station. Older snow showed somewhat higher concentrations compared to fresh snow samples indicating the influence of dry deposition of BC. In order to study in detail the impact of black carbon on snow properties, we upgraded the existing one-dimensional physical snowpack model CROCUS to account for the influence of black carbon on the absorption of radiation by the snow. A radiative transfer scheme was implemented into the snowpack model taking into account the solar zenith angle, the snow water equivalent and grain size, the soil albedo, and the concentration of black carbon in the snow. The upgraded model was applied to a high altitude site in the Himalayas using observed BC concentrations and meteorological data recorded at Pyramid station. First results of the simulations will be presented.
Effects of Black Carbon on Climate: Advances in Measurement and Modeling
Kondo, Y.
2015-04-01
Black carbon (BC) particles are non-spherical agglomerates consisting of hundreds or thousands of graphitic carbon spherules the diameters of which are about 15-50 nm. The spherules are graphitic in their molecular states and are, thus, strongly light-absorbing. BC particles are emitted by the incomplete combustion of carbon-based fossil fuels and biomass. BC mass in the atmosphere resides in agglomerates typically between 100 and 600 nm in diameter. They influence the global radiation budget by strongly absorbing solar radiation in the visible wavelengths and by changing the albedo of snow through deposition. Radiative forcing (RF) of BC is defined as the change in net radiative flux at the top of the atmosphere in W m-2 due to a change of BC between the pre-industrial time and present-day periods. The instantaneous direct radiative forcing of airborne BC particles (BC DRF), which does not include climate feedbacks, is determined by their absorption cross sections and spatial distributions. The distributions of BC are, in turn, controlled by its emission, dynamical transport, and loss during transport. The absorption cross section of BC is controlled by its optical properties (i.e., refractive index) and microphysical properties (size distribution, morphology, and mixing state). Because it is crucial to characterize these parameters, we first developed techniques to measure them accurately. Newly-developed BC measurement technologies constitute the firm basis of our studies. The techniques were applied to laboratory experiments and field observations of BC particles in air and rainwater. We also developed regional scale three-dimensional (3D) models to quantitatively interpret the observational results. One of the models calculates BC aging and optical/radiative processes explicitly without parameterizations. The reliable field measurements and model calculations of BC has enabled an improved understanding of the physical and chemical processes that control the
Automatic Black-Box Model Order Reduction using Radial Basis Functions
Energy Technology Data Exchange (ETDEWEB)
Stephanson, M B; Lee, J F; White, D A
2011-07-15
Finite elements methods have long made use of model order reduction (MOR), particularly in the context of fast freqeucny sweeps. In this paper, we discuss a black-box MOR technique, applicable to a many solution methods and not restricted only to spectral responses. We also discuss automated methods for generating a reduced order model that meets a given error tolerance. Numerical examples demonstrate the effectiveness and wide applicability of the method. With the advent of improved computing hardware and numerous fast solution techniques, the field of computational electromagnetics are progressed rapidly in terms of the size and complexity of problems that can be solved. Numerous applications, however, require the solution of a problem for many different configurations, including optimization, parameter exploration, and uncertainly quantification, where the parameters that may be changed include frequency, material properties, geometric dimensions, etc. In such cases, thousands of solutions may be needed, so solve times of even a few minutes can be burdensome. Model order reduction (MOR) may alleviate this difficulty by creating a small model that can be evaluated quickly. Many MOR techniques have been applied to electromagnetic problems over the past few decades, particularly in the context of fast frequency sweeps. Recent works have extended these methods to allow more than one parameter and to allow the parameters to represent material and geometric properties. There are still limitations with these methods, however. First, they almost always assume that the finite element method is used to solve the problem, so that the system matrix is a known function of the parameters. Second, although some authors have presented adaptive methods (e.g., [2]), the order of the model is often determined before the MOR process begins, with little insight about what order is actually needed to reach the desired accuracy. Finally, it not clear how to efficiently extend most
Reig, P.; Kylafis, N. D.
2015-12-01
Context. Galactic black-hole X-ray binaries emit a compact, optically thick, mildy relativistic radio jet when they are in the hard and hard-intermediate states, that is, typically at the beginning and the end of an X-ray outburst. In a series of papers, we have developed a jet model and have shown through Monte Carlo simulations that our model can explain many observational results. Aims: In this work, we investigate one more constraining relationship between the cutoff energy and the phase lag during the early stages of an X-ray outburst of the black-hole X-ray binary GX 339-4: the cutoff energy decreases while the phase lag increases during the brightening of the hard state. Methods: We performed Monte Carlo simulations of the Compton upscattering of soft accretion-disk photons in the jet and computed the phase lag between soft and hard photons and the cutoff energy of the resulting high-energy power law. Results: We demonstrate that our jet model naturally explains the above correlation, with a minor modification consisting of introducing an acceleration zone at the base of the jet. Conclusions: The observed correlation between the cutoff energy and the phase lag in the black-hole binary GX 339-4 suggests that the lags are produced by the hard component. Here we show that this correlation arises naturally if Comptonization in the jet produces these two quantities.
International Nuclear Information System (INIS)
A wide scope Regional Technical Co-operation Project RER/2/003 'Marine environmental assessment of the Black Sea region' is implemented by the International Atomic Energy Agency (IAEA) in the period 1995-2001. This project is initiated in response to the needs of participating Member-States - the six Black Sea coastal countries (Bulgaria, Romania, Ukraine, Russian Federation, Georgia and Turkey) to establish capabilities for reliably assessing radionuclides in the Black Sea environment and applying tracer technique to marine pollution studies. The project has various important aspects: Scientifically; one of the major environmental issue radioactivity pollution is addressed. Technically; laboratory capability for transuranic analysis is being developed. Economically; the reversing the ecological deterioration and developing sustainable uses of the Black Sea and its natural resources is one of the major interest. Politically; responsibility of pollution control and rehabilitation plans of six Black Sea countries are addressed thought various conventions and declarations. Socio-economically; fisheries and tourism sectors are expected to benefit. Highlights from the joint radioactivity monitoring program of the project among six Black Sea countries are outlined. Examples from Turkish monitoring work consists of the routine sampling of sea water, algae, mussels, fish samples and beach sand from the selected stations along the Black Sea coast are presented for illustration. Insights gained from the application of nuclear techniques for the 'Pollution Investigation of the Kucukcekmece Lake' and the 'Marine environmental assessment of the Black Sea region' Model Technical Co-operation Project carried out at the Cekmece Nuclear Research Center supporting by the IAEA are presented. Concluding remarks include the vital importance of protection of the water resources within Eurasian countries and the need for strong cooperation among nuclear research centers
Is Carbon Black a Suitable Model Colloidal Substrate for Diesel Soot?
Growney, David J; Mykhaylyk, Oleksandr O; Middlemiss, Laurence; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P
2015-09-29
Soot formation in diesel engines is known to cause premature engine wear. Unfortunately, genuine diesel soot is expensive to generate, so carbon blacks are often used as diesel soot mimics. Herein, the suitability of a commercial carbon black (Regal 250R) as a surrogate for diesel soot dispersed in engine base oil is examined in the presence of two commonly used polymeric lubricant additives. The particle size, morphology, and surface composition of both substrates are assessed using BET surface area analysis, TEM, and XPS. The extent of adsorption of a poly(ethylene-co-propylene) (dOCP) statistical copolymer or a polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) diblock copolymer onto carbon black or diesel soot from n-dodecane is compared indirectly using a supernatant depletion assay technique via UV spectroscopy. Thermogravimetric analysis is also used to directly determine the extent of copolymer adsorption. Degrees of dispersion are examined using optical microscopy, TEM, and analytical centrifugation. SAXS studies reveal some structural differences between carbon black and diesel soot particles. The mean radius of gyration determined for the latter is significantly smaller than that calculated for the former, and in the absence of any copolymer, diesel soot suspended in n-dodecane forms relatively loose mass fractals compared to carbon black. SAXS provides evidence for copolymer adsorption and indicates that addition of either copolymer transforms the initially compact agglomerates into relatively loose aggregates. Addition of dOCP or PS-PEP does not significantly affect the structure of the carbon black primary particles, with similar results being observed for diesel soot. In favorable cases, remarkably similar data can be obtained for carbon black and diesel soot when using dOCP and PS-PEP as copolymer dispersants. However, it is not difficult to identify simple copolymer-particle-solvent combinations for which substantial differences can be observed
Dexter, Jason; Fragile, P. Chris
2013-07-01
High-resolution, multiwavelength and time-domain observations of the Galactic Centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. Most models assume alignment between the accretion disc and black hole angular momentum axes, but this is not necessarily the case for geometrically thick accretion flows like that on to Sgr A*. Instead, we calculate images and spectra from a set of numerical simulations of accretion flows misaligned (`tilted') by 15° from the black hole spin axis and compare them with millimetre (mm) to near-infrared (NIR) observations. Non-axisymmetric standing shocks from eccentric fluid orbits dominate the emission, leading to a wide range of possible image morphologies. The strong effects of disc tilt lead to poorly constrained model parameters. These results suggest that previous parameter estimates from fitting aligned models, including estimates of the dimensionless black hole spin, likely only apply for small values of spin or tilt (upper limits of a 1012 K). These electrons can naturally produce the observed NIR flux, spectral index and rapid variability (`flaring'). This NIR emission is uncorrelated with that in the mm, which also agrees with observations. These are the first numerical models to explain the time-variable mm to NIR emission of Sgr A*. Predictions of the model include significant structural changes observable with mm-VLBI on both the dynamical (hour) and Lense-Thirring precession (day-year) time-scales, and ≃ 30-50 μas changes in centroid position from extreme gravitational lensing events during NIR flares, detectable with the future VLT instrument GRAVITY. We further predict that multiwavelength monitoring should find no significant correlations between mm and NIR/X-ray light curves. The weak correlations reported to date are shown to be consistent with our model, where they are artefacts of the short light-curve durations. If the observed NIR emission is caused by shock heating in
Hraba, Joseph; Siegman, Jack
1974-01-01
Black militancy is treated as an instance of class consciousness with criteria and scales developed to measure black consciousness and "self-placement" into black consciousness. These dimensions are then investigated with respect to the social and symbolic participation in the ideology of the black movement on the part of a sample of black…
Azimuthal correlations of hadrons and fragments in nucleus-nucleus collisions
Institute of Scientific and Technical Information of China (English)
LI Hui-Ling
2011-01-01
Two-particle (two-fragment) azimuthal correlation functions are studied by using a simple formula which describes uniformly azimuthal distributions of final-state charged particles and nuclear fragments.This formula is obtained in the framework of a multi-source thermal model (or multi-source ideal gas model).The calculated results are compared and found to be in agreement with the experimental data of charged hadrons and nuclear fragments in nucleus-nucleus collisions at intermediate and high energies.
Energy Technology Data Exchange (ETDEWEB)
Marklund, Magnus
2001-02-01
The work presented in this report is done in order to develop a simplified CFD model for Chemrec's pressurised black liquor gasification process. This process is presently under development and will have a number of advantages compared to conventional processes for black liquor recovery. The main goal with this work has been to get qualitative information on influence of burner design for the gas flow in the gasification reactor. Gasification of black liquor is a very complex process. The liquor is composed of a number of different substances and the composition may vary considerably between liquors originating from different mills and even for black liquor from a single process. When a black liquor droplet is gasified it loses its organic material to produce combustible gases by three stages of conversion: Drying, pyrolysis and char gasification. In the end of the conversion only an inorganic smelt remains (ideally). The aim is to get this smelt to form a protective layer, against corrosion and heat, on the reactor walls. Due to the complexity of gasification of black liquor some simplifications had to be made in order to develop a CFD model for the preliminary design of the gasification reactor. Instead of modelling droplets in detail, generating gas by gasification, sources were placed in a prescribed volume where gasification (mainly drying and pyrolysis) of the black liquor droplets was assumed to occur. Source terms for the energy and momentum equations, consistent with the mass source distribution, were derived from the corresponding control volume equations by assuming a symmetric outflow of gas from the droplets and a uniform degree of conversion of reactive components in the droplets. A particle transport model was also used in order to study trajectories from droplets entering the reactor. The resulting model has been implemented in a commercial finite volume code (AEA-CFX) through customised Fortran subroutines. The advantages with this simple
Black Hole Evaporation. A Survey
Benachenhou, Farid
1994-01-01
This thesis is a review of black hole evaporation with emphasis on recent results obtained for two dimensional black holes. First, the geometry of the most general stationary black hole in four dimensions is described and some classical quantities are defined. Then, a derivation of the spectrum of the radiation emitted during the evaporation is presented. In section four, a two dimensional model which has black hole solutions is introduced, the so-called CGHS model. These two dimensional blac...
Yohan J John; Basilis Zikopoulos; Daniel Bullock; Helen Barbas
2016-01-01
In a complex environment that contains both opportunities and threats, it is important for an organism to flexibly direct attention based on current events and prior plans. The amygdala, the hub of the brain's emotional system, is involved in forming and signaling affective associations between stimuli and their consequences. The inhibitory thalamic reticular nucleus (TRN) is a hub of the attentional system that gates thalamo-cortical signaling. In the primate brain, a recently discovered pat...
Francesco Zirilli; Francesca Mariani; Maria Cristina Recchioni; Lorella Fatone
2012-01-01
A new method for calibrating the Black-Scholes asset price dynamics model is proposed. The data used to test the calibration problem included observations of asset prices over a finite set of (known) equispaced discrete time values. Statistical tests were used to estimate the statistical significance of the two parameters of the Black-Scholes model: the volatility and the drift. The effects of these estimates on the option pricing problem were investigated. In particular, the pricing of an op...
Directory of Open Access Journals (Sweden)
Ivan Balenović
2015-02-01
Full Text Available The main aim was to develop models for predicting diameter at breast height (DBH, merchantable tree volume (V, and aboveground biomass (AGB of individual black pine (Pinus nigra Arn. trees grown in Sub-Mediterranean Croatian pure even-aged forests, which will be suitable for remote sensing based forest inventories. In total, eight variables obtained from field measurement, existing database, and digital terrain model were candidates for independent variables in regression analysis. DBH, V, and AGB were modeled as linear function of each of the independent variables, and all possible linear combinations thereof. Goodness of fit of every model was then evaluated using R2 statistic. Comparison between selected models showed that the variability of all dependent variables are explained best by models which include both crown diameter and tree height as independent variables with coefficients of determination of 0.83, 0.89, 0.82 for DBH, V, and AGB, respectively. Consequently, these models may be recommended as the most suited for DBH, V and AGB estimation of black pine trees grown in pure Sub-Mediterranean forest stands using high-resolution aerial images or high-density airborne laser scanning data. This assumption should be further validated by conducting remote sensing inventory and comparing the obtained results with field measurement results.
Directory of Open Access Journals (Sweden)
R. P. M. Topper
2011-03-01
Full Text Available High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary has been developed. A first order check of the results has been performed by comparison with the results of a recent global Cenomanian CCSM3 run, from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of the basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may have been behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling could have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario could have inhibited large scale black shale formation, as could have the opening of the Equatorial Atlantic Seaway in the post-OAE scenario.
Are black holes a serious threat to scalar field dark matter models?
Barranco, Juan; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2011-01-01
Classical scalar fields have been proposed as possible candidates for the dark matter component of the universe. Given the fact that super-massive black holes seem to exist at the center of most galaxies, in order to be a viable candidate for the dark matter halo a scalar field configuration should be stable in the presence of a central black hole, or at least be able to survive for cosmological time-scales. In the present work we consider a scalar field as a test field on a Schwarzschild background, and study under which conditions one can obtain long-lived configurations. We present a detailed study of the Klein-Gordon equation in the Schwarzschild spacetime, both from an analytical and numerical point of view, and show that indeed there exist quasi-stationary solutions that can remain surrounding a black hole for large time-scales.
Stuchlik, Zdenek; Torok, Gabriel
2013-01-01
Using known frequencies of the twin-peak high-frequency quasiperiodic oscillations (HF QPOs) and known mass of the central black hole, the black-hole dimensionless spin can be determined by assuming a concrete version of the resonance model. However, a wide range of observationally limited values of the black hole mass implies low precision of the spin estimates. We discuss the possibility of higher precision of the black hole spin measurements in the framework of a multi-resonance model inspired by observations of more than two HF QPOs in the black hole systems, which are expected to occur at two (or more) different radii of the accretion disc. For the black hole systems we focus on the special case of duplex frequencies, when the top, bottom, or mixed frequency is common at two different radii where the resonances occur giving triple frequency sets. The sets of triple frequency ratios and the related spin are given. The strong resonance model for "magic" values of the black hole spin means that two (or more...
A Pricing Method on Black-Scholes Option Model%Black-Scholes期权模型的一种定价方法
Institute of Scientific and Technical Information of China (English)
金浩; 刘新平; 李顺
2006-01-01
从微分方程的角度来诠释了Black-Scholes期权定价公式的由来.利用随机微分方程Feynman-Kac定理,推导出Black-Scholes期权定价公式.结果表明:Black-Scholes微分方程及其边界条件恰好满足于随机微分方程Feynman-Kac定理中的Cauchy问题,从而存在唯一解.
Directory of Open Access Journals (Sweden)
Petra Posedel
2006-12-01
Full Text Available The interest of professional investors in financial derivatives on the Croatian market is steadily increasing and trading is expected to start after the establishment of the legal framework. The quantification of the fair price of such financial instruments is therefore becoming increasingly important. Once the derivatives market is formed, the use of the Black-Scholes option pricing model is also expected. However, contrary to the assumptions of the Black-Scholes model, research in the field of option markets worldwide suggests that the volatility of the time-series returns is not constant over time. The present study analyzes the implications of volatility that changes over time for option pricing. The nonlinear-in-mean asymmetric GARCH model that reflects asymmetry in the distribution of returns and the correlation between returns and variance is recommended. For the purpose of illustration, we use the NGARCH model for the pricing of foreign currency options. Possible prices for such options having different strikes and maturities are then determined using Monte Carlo simulations. The improvement provided by the NGARCH model is that the option price is a function of the risk premium embedded in the underlying asset. This contrasts with the standard preference-free option pricing result that is obtained in the Black-Scholes model.
Directory of Open Access Journals (Sweden)
Guoqing Li
2014-11-01
Full Text Available Black locust (Robinia pseudoacacia L. is a tree species of high economic and ecological value, but is also considered to be highly invasive. Understanding the global potential distribution and ecological characteristics of this species is a prerequisite for its practical exploitation as a resource. Here, a maximum entropy modeling (MaxEnt was used to simulate the potential distribution of this species around the world, and the dominant climatic factors affecting its distribution were selected by using a jackknife test and the regularized gain change during each iteration of the training algorithm. The results show that the MaxEnt model performs better than random, with an average test AUC value of 0.9165 (±0.0088. The coldness index, annual mean temperature and warmth index were the most important climatic factors affecting the species distribution, explaining 65.79% of the variability in the geographical distribution. Species response curves showed unimodal relationships with the annual mean temperature and warmth index, whereas there was a linear relationship with the coldness index. The dominant climatic conditions in the core of the black locust distribution are a coldness index of −9.8 °C–0 °C, an annual mean temperature of 5.8 °C–14.5 °C, a warmth index of 66 °C–168 °C and an annual precipitation of 508–1867 mm. The potential distribution of black locust is located mainly in the United States, the United Kingdom, Germany, France, the Netherlands, Belgium, Italy, Switzerland, Australia, New Zealand, China, Japan, South Korea, South Africa, Chile and Argentina. The predictive map of black locust, climatic thresholds and species response curves can provide globally applicable guidelines and valuable information for policymakers and planners involved in the introduction, planting and invasion control of this species around the world.
Modeling kicks from the merger of generic black-hole binaries
Baker, John G; Centrella, Joan; Kelly, Bernard J; McWilliams, Sean T; Miller, M Coleman; van Meter, James R
2008-01-01
Recent numerical relativistic results demonstrate that the merger of comparable-mass spinning black holes has a maximum ``recoil kick'' of up to $\\sim 4000 \\kms$. However the scaling of these recoil velocities with mass ratio is poorly understood. We present new runs showing that the maximum possible kick parallel to the orbital axis does not scale as $\\sim\\eta^2$ (where $\\eta$ is the symmetric mass ratio), as previously proposed, but is more consistent with $\\sim\\eta^3$. We discuss the effect of this dependence on galactic ejection scenarios and retention of intermediate-mass black holes in globular clusters.
Modeling Kicks from the Merger of Generic Black-hole Binaries
Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; Miller, M. Coleman; vanMeter, James R.
2008-01-01
Recent numerical relativistic results demonstrate that the merger of comparable-mass spinning black holes has a maximum "recoil kick" of up to approx. 4000 km/s. However the scaling of these recoil velocities with mass ratio is poorly understood. We present new runs showing that the maximum possible kick parallel to the orbital axis does not scale as approx. eta(sup 2) (where eta is the symmetric mass ratio), as previously proposed, but is more consistent with approx. eta(sup 3). We discuss the effect of this dependence on galactic ejection scenarios and retention of intermediate-mass black holes in globular clusters. S
Recoiling Black Holes in Quasars
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.
Noncommutative Singular Black Holes
International Nuclear Information System (INIS)
In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t - r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.
Noncommutative Singular Black Holes
Hamid Mehdipour, S.
2010-11-01
In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t — r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.
International Nuclear Information System (INIS)
There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto an MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full three-dimensional adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2 x 1011 Msun galactic halo and its 105 Msun embedded MBH at redshift 3 in a cosmological ΛCDM simulation. The MBH feedback heats the surrounding interstellar medium (ISM) up to 106 K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. The feedback considerably changes the stellar distribution there. This new channel of feedback from a slowly growing MBH is particularly interesting because it is only locally dominant and does not require the heating of gas globally on the disk. The MBH also self-regulates its growth by keeping the surrounding ISM hot for an extended period of time.
European pricing options on modified Black-Scholes model%修正的Black-Scholes模型下的欧式期权定价
Institute of Scientific and Technical Information of China (English)
孙玉东; 师义民
2012-01-01
通常情况下,期权定价研究都假定股票价格的波动率和期望收益率为常数.假定波动率和期望收益率为股票价格的一般函数.利用金融市场复制策略及布朗运动的It(o)公式,得到欧式未定权益的一般Black-Scholes偏微分方程,并通过求解偏微分方程获得欧式期权定价公式.%Previous option pricing research typically assumes that the stock volatility and expectation return rate are constant during the life of the option. In this study, we assume the stock volatility and expectation return rate in our option valuation model are function of stock. By the self-financing strategy and Ito formula for Brownian motion, the general Black-Scholes partial differential equations for European claim and pricing formula for European option are obtained.
Energy Technology Data Exchange (ETDEWEB)
Kim, Ji-hoon; Wise, John H.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Princeton U., Astrophys. Sci. Dept.; Alvarez, Marcelo A.; /Canadian Inst. Theor. Astrophys.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys. Dept.
2011-11-04
There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto an MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full three-dimensional adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2 x 10{sup 11} M {circle_dot} galactic halo and its 10{sup 5} {circle_dot} M embedded MBH at redshift 3 in a cosmological CDM simulation. The MBH feedback heats the surrounding interstellar medium (ISM) up to 10{sup 6} K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. The feedback considerably changes the stellar distribution there. This new channel of feedback from a slowly growing MBH is particularly interesting because it is only locally dominant and does not require the heating of gas globally on the disk. The MBH also self-regulates its growth by keeping the surrounding ISM hot for an extended period of time.