Planning the digitisation, storage and access of large scale audiovisual archives

This paper presents ongoing work in PrestoSpace on how broadcast archives can plan large-scale, long-term digitization and storage projects. In our approach, carrier decay, technical obsolescence, and rapidly falling costs of mass storage are represented as a series of statistical and predictive models. The models include ongoing migration within a digital archive. The objective is to allow archive managers to investigate the trade-offs between how many items to transfer, the cost of transfer and storage, how long it will take, what quality can be achieved, how much will be lost, and what digital storage solutions to adopt over time. The process and models are based on digitization projects conducted by large broadcast archives that are currently migrating their collections into digital form. Whilst our focus is on broadcast archives, our findings should be readily transferable to other scenarios where there is a need to store large volumes of digital data over long periods of time

Circulating and persistent currents induced by a current magnification and Aharonov-Casher phase

We considered the circulating current induced by the current magnification and the persistent current induced by Aharonov-Casher flux. The persistent currents have directional dependence on the direct current flow, but the circulating currents have no directional dependence. Hence in the equilibrium, only the persistent current can survives on the ring. For the charge current, the persistent charge current cancelled between spin up and down states, because of the time reversal symmetry of the Hamiltonian on the ring. So there are only circulating charge currents on the ring for electrons with unpolarized spin in the nonequilibrium. However, only the persistent spin currents contributes to the spin currents for electrons with unpolarized spin.Comment: 9 pages and 4 ps figure

Necessary and sufficient conditions for bipartite entanglement

Necessary and sufficient conditions for bipartite entanglement are derived, which apply to arbitrary Hilbert spaces. Motivated by the concept of witnesses, optimized entanglement inequalities are formulated solely in terms of arbitrary Hermitian operators, which makes them useful for applications in experiments. The needed optimization procedure is based on a separability eigenvalue problem, whose analytical solutions are derived for a special class of projection operators. For general Hermitian operators, a numerical implementation of entanglement tests is proposed. It is also shown how to identify bound entangled states with positive partial transposition.Comment: 7 pages, 2 figur

Local well-posedness of the generalized Cucker-Smale model

In this paper, we study the local well-posedness of two types of generalized Cucker-Smale (in short C-S) flocking models. We consider two different communication weights, singular and regular ones, with nonlinear coupling velocities $v|v|^{\beta-2}$ for $\beta > \frac{3-d}{2}$. For the singular communication weight, we choose $\psi^1(x) = 1/|x|^{\alpha}$ with $\alpha \in (0,d-1)$ and $\beta \geq 2$ in dimension $d > 1$. For the regular case, we select $\psi^2(x) \geq 0$ belonging to (L_{loc}^\infty \cap \mbox{Lip}_{loc})(\mathbb{R}^d) and $\beta \in (\frac{3-d}{2},2)$. We also remark the various dynamics of C-S particle system for these communication weights when $\beta \in (0,3)$

On multipartite invariant states I. Unitary symmetry

We propose a natural generalization of bipartite Werner and isotropic states to multipartite systems consisting of an arbitrary even number of d-dimensional subsystems (qudits). These generalized states are invariant under the action of local unitary operations. We study basic properties of multipartite invariant states: separability criteria and multi-PPT conditions.Comment: 9 pages; slight correction

Directional dependence of spin currents induced by Aharonov-Casher phase

We have calculated the persistent spin current of an open ring induced by the Aharonov-Casher phase. For unpolarized electrons there exist no persistent charge currents, but persistent spin currents. We show that, in general, the magnitude of the persistent spin current in a ring depends on the direction of the direct current flow from one reservoir to another. The persistent spin current is modulated by the cosine function of the spin precession angle. The nonadiabatic Aharonov-Casher phase gives anomalous behaviors. The Aharonov-Anandan phase is determined by the solid angle of spin precession. When the nonadiabatic Aharonov-Anandan phase approaches a constant value with the increase of the electric field, the periodic behavior of the spin persistent current occurs in an adiabatic limit. In this limit the periodic behavior of the persistent spin current could be understood by the effective spin-dependent Aharonov-Bohm flux.Comment: 16pages, 5 postscript figures. Submitted to Phys. Rev.

The Gaugino Code

Gauginos might play a crucial role in the search for supersymmetry at the Large Hadron Collider (LHC). Mass predictions for gauginos are rather robust and often related to the values of the gauge couplings. We analyse the ratios of gaugino masses in the LHC energy range for various schemes of supersymmetry breakdown and mediation. Three distinct mass patterns emerge.Comment: 42 pages, Latex; a discussion of deflected anomaly mediation added, references adde

Charge Frustration Effects in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays

We investigate the quantum phase transitions in two capacitively coupled two-dimensional Josephson-junction arrays with charge frustration. The system is mapped onto the S=1 and $S=1/2$ anisotropic Heisenberg antiferromagnets near the particle-hole symmetry line and near the maximal-frustration line, respectively, which are in turn argued to be effectively described by a single quantum phase model. Based on the resulting model, it is suggested that near the maximal frustration line the system may undergo a quantum phase transition from the charge-density wave to the super-solid phase, which displays both diagonal and off- diagonal long-range order.Comment: 6 pages, 6 figures, to appear in Phys. Rev.

Inhibition of Food Intake by PACAP in the Hypothalamic Ventromedial Nuclei is Mediated by NMDA Receptors

Central injections of pituitary adenylate cyclase-activating polypeptide (PACAP) into the ventromedial nuclei (VMN) of the hypothalamus produce hypophagia that is dependent upon the PAC1 receptor; however, the signaling downstream of this receptor in the VMN is unknown. Though PACAP signaling has many targets, this neuropeptide has been shown to influence glutamate signaling in several brain regions through mechanisms involving NMDA receptor potentiation via activation of the Src family of protein tyrosine kinases. With this in mind, we examined the Src-NMDA receptor signaling pathway as a target for PACAP signaling in the VMN that may mediate its effects on feeding behavior. Under nocturnal feeding conditions, NMDA receptor antagonism prior to PACAP administration into the VMN attenuated PACAP-mediated decreases in feeding suggesting that glutamatergic signaling via NMDA receptors is necessary for PACAP-induced hypophagia. Furthermore, PACAP administration into the VMN resulted in increased tyrosine phosphorylation of the GluN2B subunit of the NMDA receptor, and inhibition of Src kinase activity also blocked the effects of PACAP administration into the VMN on feeding behavior. These results indicate that PACAP neurotransmission in the VMN likely augments glutamate signaling by potentiating NMDA receptors activity through the tyrosine phosphorylation events mediated by the Src kinase family, and modulation of NMDA receptor activity by PACAP in the hypothalamus may be a primary mechanism for its regulation of food intake

A QCD Axion from Higher Dimensional Gauge Field

We point out that a QCD axion solving the strong CP problem can arise naturally from parity-odd gauge field C_M in 5-dimensional (5D) orbifold field theory. The required axion coupling to the QCD anomaly comes from the 5D Chern-Simons coupling, and all other unwanted U(1)_{PQ} breaking axion couplings can be avoided naturally by the 5D gauge symmetry of C_M and the 5D locality. If the fifth dimension is warped, the resulting axion scale is suppressed by small warp factor compared to the Planck scale, thereby the model can generate naturally an intermediate axion scale f_a=10^{10} - 10^{12}GeV.Comment: 5 pages, Revtex