Investigation of Lighting Levels for Pedestrians - Some questions about lighting levels of current lighting standards

22-23 September, 200

The Structure of n-Point One-Loop Open Superstring Amplitudes

In this article we present the worldsheet integrand for one-loop amplitudes in maximally supersymmetric superstring theory involving any number n of massless open string states. The polarization dependence is organized into the same BRST invariant kinematic combinations which also govern the leading string correction to tree level amplitudes. The dimensions of the bases for both the kinematics and the associated worldsheet integrals is found to be the unsigned Stirling number S_3^{n-1} of first kind. We explain why the same combinatorial structures govern on the one hand finite one-loop amplitudes of equal helicity states in pure Yang Mills theory and on the other hand the color tensors at quadratic alpha prime order of the color dressed tree amplitude.Comment: 75 pp, 8 figs, harvmac TeX, v2: published versio

Fight to Be Forgotten: Exploring the Efficacy of Data Erasure in Popular Operating Systems

A long history of longitudinal and intercultural research has identified decommissioned storage devices (e.g., USB memory sticks) as a serious privacy and security threat. Sensitive data deleted by previous owners have repeatedly been found on second-hand USB sticks through forensic analysis. Such data breaches are unlikely to occur when data is securely erased, rather than being deleted. Yet, research shows people confusing these two terms. In this paper, we report on an investigation of possible causes for this confusion. We analysed the user interface of two popular operating systems and found: (1) inconsistencies in the language used around delete and erase functions, (2) insecure default options, and (3) unclear or incomprehensible information around delete and erase functions. We discuss how this could result in data controllers becoming non-compliant with a legal obligation for erasure, putting data subjects at risk of accidental data breaches from the decommissioning of storage devices. Finally, we propose improvements to the design of relevant user interface elements and the development of official guidelines for best practice on GDPR compatible data erasure procedures

Nature and Community Cohesion

Individuals may be losing touch with nature as their contact with it decreases worldwide. While the consequences for people’s personal well-being outcomes are becoming well documented, there is almost no research examining the social correlates of contact with nature. This paper used a large nationally representative sample to link objective (% greenspace) and subjective measurements of contact with nature, community cohesion, and local crime incidence. The perceived quality, views, and amount of time spent in nature were linked to more community cohesion, and in turn the perception of cohesive communities enhances individual well-being outcomes and contributions back to society through higher workplace productivity and environmentally responsible behaviors. Findings also indicated that local nature was linked to lower crime both directly and indirectly through its effects on community cohesion.This research was funded in part by the ESRC (project number RES-064-27-0019).This is the author accepted manuscript. The final version is available from Oxford University Press via http://dx.doi.org/10.1093/biosci/biv15

One-loop SYM-supergravity relation for five-point amplitudes

We derive a linear relation between the one-loop five-point amplitude of N=8 supergravity and the one-loop five-point subleading-color amplitudes of N=4 supersymmetric Yang-Mills theory.Comment: 17 pages, 2 figures; v2: very minor correction

Abstract robust coarse spaces for systems of PDEs via generalized eigenproblems in the overlaps

Coarse spaces are instrumental in obtaining scalability for domain decomposition methods for partial differential equations (PDEs). However, it is known that most popular choices of coarse spaces perform rather weakly in the presence of heterogeneities in the PDE coefficients, especially for systems of PDEs. Here, we introduce in a variational setting a new coarse space that is robust even when there are such heterogeneities. We achieve this by solving local generalized eigenvalue problems in the overlaps of subdomains that isolate the terms responsible for slow convergence. We prove a general theoretical result that rigorously establishes the robustness of the new coarse space and give some numerical examples on two and three dimensional heterogeneous PDEs and systems of PDEs that confirm this property

Comments on regularization of identity based solutions in string field theory

We analyze the consistency of the recently proposed regularization of an identity based solution in open bosonic string field theory. We show that the equation of motion is satisfied when it is contracted with the regularized solution itself. Additionally, we propose a similar regularization of an identity based solution in the modified cubic superstring field theory.Comment: 24 pages, two subsections added, two references adde

Spectrum from the warped compactifications with the de Sitter universe

We discuss the spectrum of the tensor metric perturbations and the stability of warped compactifications with the de Sitter spacetime in the higher-dimensional gravity. The spacetime structure is given in terms of the warped product of the non-compact direction, the spherical internal dimensions and the four-dimensional de Sitter spacetime. To realize a finite bulk volume, we construct the brane world model, using the cut-copy-paste method. Then, we compactify the spherical directions on the brane. In any case, we show the existence of the massless zero mode and the mass gap of it with massive Kaluza-Klein modes. Although the brane involves the spherical dimensions, no light massive mode is excited. We also investigate the scalar perturbations, and show that the model is unstable due to the existence of a tachyonic bound state, which seems to have the universal negative mass square, irrespective of the number of spacetime dimensions.Comment: Journal version (JHEP

Charge current in ferromagnet-superconductor junction with pairing state of broken time-reversal symmetry

We calculate the tunneling conductance spectra of a ferromagnetic metal/insulator/superconductor using the Blonder-Tinkham-Klapwijk (BTK) formulation. Two possible states for the superconductor are considered with the time reversal symmetry ($\cal{T}$) broken, i.e., $d_{x^2-y^2}+is$, or $d_{x^2-y^2}+id_{xy}$. In both cases the tunneling conductance within the gap is suppressed with the increase of the exchange interaction due to the suppression of the Andreev reflection. In the $(d_{x^2-y^2}+is)$-wave case the peaks that exist when the ferromagnet is a normal metal in the amplitude of the s-wave component due to the bound state formation are reduced symmetrically, with the increase of the exchange field, while in the $(d_{x^2-y^2}+id_{xy})$-wave case the residual density of states within the gap develops a dip around E=0 with the increase of the exchange field. These results would be useful to discriminate between $\cal{T}$-broken pairing states near the surface in high-$T_c$ superconductorsComment: 17 pages with 11 figure