Antibranes don't go black

When D-branes are inserted in flux backgrounds of opposite charge, the resulting solution has a certain singularity in the fluxes. Recently it has been argued, using numerical solutions, that for anti-D3 branes in the Klebanov-Strassler background these singularities cannot be cloaked by a horizon, which strongly suggests they are not physical. In this note we provide an analytic proof that the singularity of all codimension-three antibrane solutions (such as anti-D6 branes in massive type IIA supergravity or anti-D3 branes smeared on the T^3 of R^3xT^3 with fluxes) cannot be hidden behind a horizon, and that the charge of black branes with smooth event horizons must have the same sign as the charge of the flux background. Our result indicates that infinitesimally blackening the antibranes immediately triggers brane-flux annihilation, and strengthens the intuition that antibranes placed in flux with positive charge immediately annihilate against it.Comment: 9 pages, 1 figur

10 + 1 to 3 + 1 in an Early Universe with mutually BPS Intersecting Branes

We assume that the early universe is homogeneous, anisotropic, and is dominated by the mutually BPS 22'55' intersecting branes of M theory. The spatial directions are all taken to be toroidal. Using analytical and numerical methods, we study the evolution of such an universe. We find that, asymptotically, three spatial directions expand to infinity and the remaining spatial directions reach stabilised values. Any stabilised values can be obtained by a fine tuning of initial brane densities. We give a physical description of the stabilisation mechanism. Also, from the perspective of four dimensional spacetime, the effective four dimensional Newton's constant G_4 is now time varying. Its time dependence will follow from explicit solutions. We find in the present case that, asymptotically, G_4 exhibits characteristic log periodic oscillations.Comment: Latex file, 59 pages, 7 figures. Version 2: A minor correction and a reference added. Version 3: Critical discussion of the main assumptions is added in sections I and VIII; two references added. To appear in Physical Review

Separated magnet yoke for permanent magnet linear generator for marine wave energy converters

In this paper the performance of a longitudinal flux permanent magnet linear generator (PMLG) for wave energy converters (WEC) is investigated. The influence of the number of slots per pole, phase q and the number of stator's winding sections are analysed. The power output and the cogging forces in the PMLG are calculated and reviewed with respect to the above design parameters. In addition, an optimised PMLG model is designed and simulated. Three-dimensional Finite Element Method (FEM) is used for solving the combined field and circuit equations of the generator.The PRIMaRE project

Creation of Fundamental Strings by Crossing D-branes

We study the force balance between orthogonally positioned $p$-brane and $(8-p)$-brane. The force due to graviton and dilaton exchange is repulsive in this case. We identify the attractive force that balances this repulsion as due to one-half of a fundamental string stretched between the branes. As the $p$-brane passes through the $(8-p)$-brane, the connecting string changes direction, which may be interpreted as creation of one fundamental string. We show this directly from the structure of the Chern-Simons terms in the D-brane effective actions. We also discuss the effect of string creation on the 0-brane quantum mechanics in the type I' theory. The creation of a fundamental string is related by U-duality to the creation of a 3-brane discussed by Hanany and Witten. Both processes have a common origin in M-theory: as two M5-branes with one common direction cross, a M2-brane stretched between them is created.Comment: 6 pages, Late

Solitons and excitations in the duality-based matrix model

We analyse a specific, duality-based generalization of the hermitean matrix model. The existence of two collective fields enables us to describe specific excitations of the hermitean matrix model. By using these two fields, we construct topologically non-trivial solutions (BPS solitons) of the model. We find the low-energy spectrum of quantum fluctuations around the uniform solution. Furthermore, we construct the wave functional of the ground state and obtain the corresponding Green function.Comment: 13 pages,v2: new solutions constructed, title changed accordingl

NFV service dynamicity with a DevOps approach : demonstrating zero-touch deployment & operations

Next generation network services will be realized by NFV-based microservices to enable greater dynamics in deployment and operations. Here, we present a demonstrator that realizes this concept using the NFV platform built in the EU FP7 project UNIFY. Using the example of an Elastic Router service, we show automated deployment and configuration of service components as well as corresponding monitoring components facilitating automated scaling of the entire service. We also demonstrate automatic execution of troubleshooting and debugging actions. Operations of the service are inspired by DevOps principles, enabling quick detection of operational conditions and fast corrective actions. This demo conveys essential insights on how the life-cycle of an NFV-based network service may be realized in future NFV platforms

(Anti-)Brane backreaction beyond perturbation theory

We improve on the understanding of the backreaction of anti-D6-branes in a flux background that is mutually BPS with D6-branes. This setup is analogous to the study of the backreaction of anti-D3-branes inserted in the KS throat, but does not require us to smear the anti-branes or do a perturbative analysis around the BPS background. We solve the full equations of motion near the anti-D6-branes and show that only two boundary conditions are consistent with the equations of motion. Upon invoking a topological argument we eliminate the boundary condition with regular H flux since it cannot lead to a solution that approaches the right kind of flux away from the anti-D6-brane. This leaves us with a boundary condition which has singular, but integrable, H flux energy density.Comment: 12 pages + appendices, 1 figure; v2: minor changes, version published in JHE

Ultimate pH values and bacteriological condition of meat and stress metabolites in blood of transported reindeer bulls

Twenty-three reindeer bulls, aged 2-3 years, fed during two winter months at the Vuolda reindeer research station in Arjeplog, Sweden, were used in the study. The first group of eight reindeer was moved from their feeding corral to a selection corral, captured by lasso and stunned with a captive bolt outside the selection corral. The second group of seven reindeer was moved to the selection corral, captured by lasso and restrained, after which they were loaded onto a lorry- and transported for 1 hour and then slaughtered. The third group of eight reindeer was moved to the selection corral and herded directly onto the lorry, without any manual handling. They were transported for 5 h and then slaughtered. In both transport groups, four reindeer were fitted with pre-programmed automatic blood sampling equipment (ABSE). ABSE sampled blood at predetermined times via a jugular vein catheter. Ultimate pH-values in three muscles (Mm. longissimus, triceps brachii and biceps femoris) were significantly lower in the group carefully handled and transported for 5 h compared with the other two groups. The physiological mechanisms behind these results are discussed. Samples from M. semimembranosus were collected at slaughter and after 2, 6 and 10 days of refrigerated storage (+4 °C). The samples were analysed for total counts of aerobic bacteria (pour-plated in Tryptone Glucose Extract Agar, Difco, incubated at 20 °C and 30 °C, respectively for 72 h), coliform bacteria 37 °C (pour-plated in Violet Red Bile Agar, Oxoid, incubated at 37 °C for 24 h), Enterococci (surface-plated onto Slantez and Bartley Agar, Oxoid, incubated at 44 °C for 48 h) and Bacillus cereus (surface-plated onto Blood Agar Plates (Blood Agar Base, Difco, supplemented with 5% defibrinated horse blood) 30 °C for 24 h). All samples fell in the range 'fit for consumption'. At slaughter, there was no difference in ASAT activity, urea and Cortisol concentrations between the two transported groups. However, the plasma ASAT activity and urea concentrations at slaughter were significantly lower in the non-transported group. In both transport groups, the plasma Cortisol concentrations increased during loading onto and unloading from the lorry. Abomasal lesions were observed in all treatment groups. It was concluded that reindeer showed an acute stress response to manual handling and transport

The problematic backreaction of SUSY-breaking branes

In this paper we investigate the localisation of SUSY-breaking branes which, in the smeared approximation, support specific non-BPS vacua. We show, for a wide class of boundary conditions, that there is no flux vacuum when the branes are described by a genuine delta-function. Even more, we find that the smeared solution is the unique solution with a regular brane profile. Our setup consists of a non-BPS AdS_7 solution in massive IIA supergravity with smeared anti-D6-branes and fluxes T-dual to ISD fluxes in IIB supergravity.Comment: 27 pages, Latex2e, 5 figure