Running a Production Grid Site at the London e-Science Centre

This paper describes how the London e-Science Centre cluster MARS, a production 400+ Opteron CPU cluster, was integrated into the production Large Hadron Collider Compute Grid. It describes the practical issues that we encountered when deploying and maintaining this system, and details the techniques that were applied to resolve them. Finally, we provide a set of recommendations based on our experiences for grid software development in general that we believe would make the technology more accessible. © 2006 IEEE

Lightside Atmospheric Revitalization System

The system was studied as a replacement to the present baseline LiOH system for extended duration shuttle missions. The system consists of three subsystems: a solid amine water desorbed regenerable carbon dioxide removal system, a water vapor electrolysis oxygen generating system, and a Sabatier reactor carbon dioxide reduction system. The system is designed for use on a solar powered shuttle vehicle. The majority of the system's power requirements are utilized on the Sun side of each orbit, when solar power is available

Homogeneous nucleation in associated vapors. I. Acetic acid

Homogeneous nucleation measurements on acetic acid vapor are reported. The presence of the relatively stable association clusters tends to stabilize the vapor with regard to homogeneous nucleation. The variation of the critical supersaturation with temperature for acetic acid vapor was found to agree well with the predictions of the Katz–Saltsburg–Reiss theory for nucleation in associated vapors

Differential Vulnerability to Window Collision Mortality Among Migratory Songbird Species

Millions of birds die annually in North America by colliding with windows. I investigated differential vulnerability to window collision among migratory songbird species using long-term citizen science datasets from two bird banding stations and the fatal light awareness program. I used negative binomial regressions to model species-specific catch ratios, a mixed-effects negative binomial regression to model trophic guild-specific catch ratios and mixed-effects logistic regressions to model the odds of catching different age classes. Species-specific vulnerability varied significantly. Blue-headed Vireos, Yellow-rumped Warblers and Ruby-crowned Kinglets were least vulnerable, while Ovenbirds, Common Yellowthroats, Fox Sparrows and Bay-breasted Warblers were most vulnerable. Foraging height influenced vulnerability with ground foragers being most vulnerable. The effect of age varied across species, with only some species showing significant effects. This study contributes to the growing foundation that is required for future studies to investigate why these factors influence vulnerability and how to minimize future collision mortality

Frequentist Analysis of the Parameter Space of Minimal Supergravity

We make a frequentist analysis of the parameter space of minimal supergravity (mSUGRA), in which, as well as the gaugino and scalar soft supersymmetry-breaking parameters being universal, there is a specific relation between the trilinear, bilinear and scalar supersymmetry-breaking parameters, A_0 = B_0 + m_0, and the gravitino mass is fixed by m_{3/2} = m_0. We also consider a more general model, in which the gravitino mass constraint is relaxed (the VCMSSM). We combine in the global likelihood function the experimental constraints from low-energy electroweak precision data, the anomalous magnetic moment of the muon, the lightest Higgs boson mass M_h, B physics and the astrophysical cold dark matter density, assuming that the lightest supersymmetric particle (LSP) is a neutralino. In the VCMSSM, we find a preference for values of m_{1/2} and m_0 similar to those found previously in frequentist analyses of the constrained MSSM (CMSSM) and a model with common non-universal Higgs masses (NUHM1). On the other hand, in mSUGRA we find two preferred regions: one with larger values of both m_{1/2} and m_0 than in the VCMSSM, and one with large m_0 but small m_{1/2}. We compare the probabilities of the frequentist fits in mSUGRA, the VCMSSM, the CMSSM and the NUHM1: the probability that mSUGRA is consistent with the present data is significantly less than in the other models. We also discuss the mSUGRA and VCMSSM predictions for sparticle masses and other observables, identifying potential signatures at the LHC and elsewhere.Comment: 18 pages 27 figure

The dynamics of central control and subsidiary autonomy in the management of human resources: case study evidence from US MNCs in the UK

This article revisits a central question in the debates on the management of multinationals: the balance between centralized policy-making and subsidiary autonomy. It does so through data from a series of case studies on the management of human resources in American multinationals in the UK. Two strands of debate are confronted. The first is the literature on differences between multinationals of different national origins which has shown that US companies tend to be more centralized, standardized, and formalized in their management of human resources. It is argued that the literature has provided unconvincing explanations of this pattern, failing to link it to distinctive features of the American business system in which US multinationals are embedded. The second strand is the wider debate on the balance between centralization and decentralization in multinationals. It is argued that the literature neglects important features of this balance: the contingent oscillation between centralized and decentralized modes of operation and (relatedly) the way in which the balance is negotiated by organizational actors through micro-political processes whereby the external structural constraints on the company are defined and interpreted. In such negotiation, actors’ leverage often derives from exploiting differences between the national business systems in which the multinational operates

Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial

The following article appeared Pacheco-Pena, V., Orazbayev, B., Torres, V., Beruete, M., & Navarro-Cia, M. (n.d). Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial. Applied Physics Letters, 103(18), and may be found at http://dx.doi.org/10.1063/1.4827876.A 1.5λ0 -thick planoconcave zoned lens based on the fishnet metamaterial is demonstrated experimentally at millimeter wavelengths. The zoning technique applied allows a volume reduction of 60% compared to a full fishnet metamaterial lens without any deterioration in performance. The structure is designed to exhibit an effective refractive index n = -0.25 at f = 56.7GHz (λ0 = 5.29 mm) with a focal length FL = 47.62 mm = 9λ0. The experimental enhancement achieved is 11.1dB, which is in good agreement with simulation and also with previous full fishnet metamaterial lenses and opens the door for integrated solutions.This work was supported in part by the Spanish Government under contract Consolider Engineering Metamaterials CSD2008-00066 and contract TEC2011- 28664-C02-01. V.P.-P. was sponsored by Spanish Ministerio de Educacion, Cultura y Deporte under Grant No. FPU AP- 2012-3796. B.O. was sponsored by Spanish Ministerio de Economıa y Competitividad under Grant No. FPI BES-2012- 054909. V.T. is sponsored by the Universidad Publica de Navarra. M.B. is sponsored by the Spanish Government via RYC-2011-08221. M.N.-C. was supported by the Imperial College Junior Research Fellowship