6,164 research outputs found
d=4 Attractors, Effective Horizon Radius and Fake Supergravity
We consider extremal black hole attractors (both BPS and non-BPS) for N=3 and
N=5 supergravity in d=4 space-time dimensions. Attractors for matter-coupled
N=3 theory are similar to attractors in N=2 supergravity minimally coupled to
Abelian vector multiplets. On the other hand, N=5 attractors are similar to
attractors in N=4 pure supergravity, and in such theories only 1\N-BPS
non-degenerate solutions exist. All the above mentioned theories have a simple
interpretation in the first order (fake supergravity) formalism. Furthermore,
such theories do not have a d=5 uplift. Finally we comment on the "duality"
relations among the attractor solutions of N\geq2 supergravities sharing the
same full bosonic sector.Comment: 1+47 pages, 2 Tables. v2: Eqs. (2.3),(2.4) and Footnote 3 added;
minor cosmetic changes; to appear in PR
Intersecting Attractors
We apply the entropy formalism to the study of the near-horizon geometry of
extremal black p-brane intersections in D>5 dimensional supergravities. The
scalar flow towards the horizon is described in terms an effective potential
given by the superposition of the kinetic energies of all the forms under which
the brane is charged. At the horizon active scalars get fixed to the minima of
the effective potential and the entropy function is given in terms of U-duality
invariants built entirely out of the black p-brane charges. The resulting
entropy function reproduces the central charges of the dual boundary CFT and
gives rise to a Bekenstein-Hawking like area law. The results are illustrated
in the case of black holes and black string intersections in D=6, 7, 8
supergravities where the effective potentials, attractor equations, moduli
spaces and entropy/central charges are worked out in full detail.Comment: 1+41 pages, 2 Table
Effects of preplasma scale length and laser intensity on the divergence of laser-generated hot electrons.
We report on a numerical study of the effects of preplasma scale length and laser intensity on the hot-electron (â„1 MeV) divergence angle using full-scale 2D3V (two dimensional in space, three dimensional in velocity) simulations including a self-consistent laser-plasma interaction and photoionization using the particle-in-cell code LSP. Our simulations show that the fast-electron divergence angle increases approximately linearly with the preplasma scale length for a fixed laser intensity. On the other hand, for a fixed preplasma scale length, the laser intensity has little effect on the divergence angle in the range between 10(18) and 10(21) W/cm(2). These findings have important implications for the interpretation of experimental results
Quantifying signals with power-law correlations: A comparative study of detrended fluctuation analysis and detrended moving average techniques
Detrended fluctuation analysis (DFA) and detrended moving average (DMA) are
two scaling analysis methods designed to quantify correlations in noisy
non-stationary signals. We systematically study the performance of different
variants of the DMA method when applied to artificially generated long-range
power-law correlated signals with an {\it a-priori} known scaling exponent
and compare them with the DFA method. We find that the scaling
results obtained from different variants of the DMA method strongly depend on
the type of the moving average filter. Further, we investigate the optimal
scaling regime where the DFA and DMA methods accurately quantify the scaling
exponent , and how this regime depends on the correlations in the
signal. Finally, we develop a three-dimensional representation to determine how
the stability of the scaling curves obtained from the DFA and DMA methods
depends on the scale of analysis, the order of detrending, and the order of the
moving average we use, as well as on the type of correlations in the signal.Comment: 15 pages, 16 figure
Acute adrenal failure (AAF) as the presenting symptom of primary antiphospholipid syndrome (APS)
Magnetic stress as a driving force of structural distortions: the case of CrN
We show that the observed transition from rocksalt to orthorhombic P
symmetry in CrN can be understood in terms of stress anisotropy. Using local
spin density functional theory, we find that the imbalance between stress
stored in spin-paired and spin-unpaired Cr nearest neighbors causes the
rocksalt structure to be unstable against distortions and justifies the
observed antiferromagnetic ordering. This stress has a purely magnetic origin,
and may be important in any system where the coupling between spin ordering and
structure is strong.Comment: 4 pages (two columns) 4 figure
Distributed coherent manipulation of qutrits by virtual excitation processes
We propose a scheme for the deterministic coherent manipulation of two atomic
qutrits, trapped in separate cavities coupled through a short optical fibre or
optical resonator. We study such a system in the regime of dispersive
atom-field interactions, where the dynamics of atoms, cavities and fibre
operates through virtual population of both the atomic excited states and
photonic states in the cavities and fibre. We show that the resulting effective
dynamics allows for the creation of robust qutrit entanglement, and thoroughly
investigate the influence of imperfections and dissipation, due to atomic
spontaneous emission and photon leakage, on the entanglement of the two qutrits
state.Comment: 15 pages, 4 figure
Anomalous relaxations and chemical trends at III-V nitride non-polar surfaces
Relaxations at nonpolar surfaces of III-V compounds result from a competition
between dehybridization and charge transfer. First principles calculations for
the (110) and (100) faces of zincblende and wurtzite AlN, GaN and InN
reveal an anomalous behavior as compared with ordinary III-V semiconductors.
Additional calculations for GaAs and ZnO suggest close analogies with the
latter. We interpret our results in terms of the larger ionicity (charge
asymmetry) and bonding strength (cohesive energy) in the nitrides with respect
to other III-V compounds, both essentially due to the strong valence potential
and absence of core states in the lighter anion. The same interpretation
applies to Zn II-VI compounds.Comment: RevTeX 7 pages, 8 figures included; also available at
http://kalix.dsf.unica.it/preprints/; improved after revie
Production of annual ryegrass with different doses of nitrogen fertilization in topdressing.
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Structure-guided design and optimization of small molecules targeting the protein-protein interaction between the von hippel-lindau (VHL) E3 ubiquitin ligase and the hypoxia inducible factor (HIF) alpha subunit with in vitro nanomolar affinities
E3 ubiquitin ligases are attractive targets in the ubiquitin-proteasome system, however, the development of small-molecule ligands has been rewarded with limited success. The von Hippel-Lindau protein (pVHL) is the substrate recognition subunit of the VHL E3 ligase that targets HIF-1α for degradation. We recently reported inhibitors of the pVHL:HIF-1α interaction, however they exhibited moderate potency. Herein, we report the design and optimization, guided by X-ray crystal structures, of a ligand series with nanomolar binding affinities
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