Parallelizing the QUDA Library for Multi-GPU Calculations in Lattice Quantum Chromodynamics

Graphics Processing Units (GPUs) are having a transformational effect on numerical lattice quantum chromodynamics (LQCD) calculations of importance in nuclear and particle physics. The QUDA library provides a package of mixed precision sparse matrix linear solvers for LQCD applications, supporting single GPUs based on NVIDIA's Compute Unified Device Architecture (CUDA). This library, interfaced to the QDP++/Chroma framework for LQCD calculations, is currently in production use on the "9g" cluster at the Jefferson Laboratory, enabling unprecedented price/performance for a range of problems in LQCD. Nevertheless, memory constraints on current GPU devices limit the problem sizes that can be tackled. In this contribution we describe the parallelization of the QUDA library onto multiple GPUs using MPI, including strategies for the overlapping of communication and computation. We report on both weak and strong scaling for up to 32 GPUs interconnected by InfiniBand, on which we sustain in excess of 4 Tflops.Comment: 11 pages, 7 figures, to appear in the Proceedings of Supercomputing 2010 (submitted April 12, 2010

Eye movement desensitisation and reprocessing for offence-related trauma in a mentally disordered sexual offender

Research demonstrates a high incidence of offence-related trauma in mentally disordered offenders convicted of violent and sexual offences. The adaptive information processing (AIP) model offers a theoretical framework for understanding the hypothesised relationship between offence-related trauma and reoffending. Evidence suggests that for a sub-population of offenders presenting with offence-related trauma: (1) therapy may retraumatise them, and (2) unresolved trauma severely blocks the positive benefits of talking therapies. Thus, it is postulated that traumatised violent and sexual offenders may be released into the community when they are still at risk of reoffending. A single case study is presented, which describes the application of eye movement desensitisation and reprocessing (EMDR) for a sexual offender presenting with offence-related trauma, whose offences occurred in the context of serious mental disorder. The identification of offence-related trauma and subsequent resolution of trauma symptomatology are discussed in regard to effective offender rehabilitation. Furthermore, the idiosyncratic nature of offence-related trauma and the application of the standard EMDR protocol for a single traumatic event are considered

Non-equilibrium dynamic critical scaling of the quantum Ising chain

We solve for the time-dependent finite-size scaling functions of the 1D transverse-field Ising chain during a linear-in-time ramp of the field through the quantum critical point. We then simulate Mott-insulating bosons in a tilted potential, an experimentally-studied system in the same equilibrium universality class, and demonstrate that universality holds for the dynamics as well. We find qualitatively athermal features of the scaling functions, such as negative spin correlations, and show that they should be robustly observable within present cold atom experiments.Comment: 4 pages + 2 page supplemen

Income and happiness: Evidence, explanations and economic implications

There is now a great deal of micro-econometric evidence, both cross-section and panel, showing that income is positively correlated with well-being. Yet the famous Easterlin paradox shows essentially no change in average happiness at the country level, despite spectacular rises in per capita GDP. We argue that survey well-being questions are indeed good proxy measures of utility, and resolve the Easterlin paradox by appealing to income comparisons: these can be to others (social comparisons) or to oneself in the past (habituation). We review a substantial amount of econometric, experimental and neurological literature consistent with comparisons, and then spell out the implications for a wide range of economic issues.income ; happiness ; social comparisons ; habituation ; economic policy

Transcriptomic profiling of human breast and melanoma cells selected by migration through narrow constraints

The metastatic spread of cancer cells is a step-wise process that starts with dissociation from primary tumours and local invasion of adjacent tissues. The ability to invade local tissues is the product of several processes, including degradation of extracellular matrices (ECM) and movement of tumour cells through physically-restricting gaps. To identify properties contributing to tumour cells squeezing through narrow gaps, invasive MDA-MB-231 human breast cancer and MDA-MB-435 human melanoma cells were subjected to three successive rounds of selection using cell culture inserts with highly constraining 3 μm pores. For comparison purposes, flow cytometry was also employed to enrich for small diameter MDA-MB-231 cells. RNA-Sequencing (RNA-seq) using the Illumina NextSeq 500 platform was undertaken to characterize how gene expression differed between parental, invasive pore selected or small diameter cells. Gene expression results obtained by RNA-seq were validated by comparing with RT-qPCR. Transcriptomic data generated could be used to determine how alterations that enable cell passage through narrow spaces contribute to local invasion and metastasis

Beyond Goldwater-Nichols

This report culminated almost two years of effort at CSIS, which began by developing an approach for both revisiting the Goldwater-Nichols Department of Defense Reorganization Act of 1986 and for addressing issues that were beyond the scope of that landmark legislation