WorldWideScience

Sample records for mpi

  1. Processing MPI Datatypes Outside MPI

    Science.gov (United States)

    Ross, Robert; Latham, Robert; Gropp, William; Lusk, Ewing; Thakur, Rajeev

    The MPI datatype functionality provides a powerful tool for describing structured memory and file regions in parallel applications, enabling noncontiguous data to be operated on by MPI communication and I/O routines. However, no facilities are provided by the MPI standard to allow users to efficiently manipulate MPI datatypes in their own codes.

  2. Exposing MPI Objects for Debugging

    DEFF Research Database (Denmark)

    Brock-Nannestad, Laust; DelSignore, John; Squyres, Jeffrey M.

    Developers rely on debuggers to inspect application state. In applications that use MPI, the Message Passing Interface, the MPI runtime contains an important part of this state. The MPI Tools Working Group has proposed an interface for MPI Handle Introspection. It allows debuggers and MPI impleme...

  3. pupyMPI - MPI implemented in pure Python

    DEFF Research Database (Denmark)

    Bromer, Rune; Hantho, Frederik; Vinter, Brian

    2011-01-01

    As distributed memory systems have become common, the de facto standard for communication is still the Message Passing Interface (MPI). pupyMPI is a pure Python implementation of a broad subset of the MPI 1.3 specifications that allows Python programmers to utilize multiple CPUs with datatypes...

  4. MPI@LHC Talk.

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00392933; The ATLAS collaboration

    2016-01-01

    Draft version of talk for MPI@LHC, regarding the topic of "Monte Carlo Tuning @ ATLAS". The talk introduces the event generator chain, concepts of tuning, issues/problems with over tuning, and then proceeds to explain 3(4) tunes performed at ATLAS. A 4th tune known as A15-MG5aMC@NLO(-TTBAR) is also included, but is awaiting note approval.

  5. MPI_XSTAR: MPI-based parallelization of XSTAR program

    Science.gov (United States)

    Danehkar, A.

    2017-12-01

    MPI_XSTAR parallelizes execution of multiple XSTAR runs using Message Passing Interface (MPI). XSTAR (ascl:9910.008), part of the HEASARC's HEAsoft (ascl:1408.004) package, calculates the physical conditions and emission spectra of ionized gases. MPI_XSTAR invokes XSTINITABLE from HEASoft to generate a job list of XSTAR commands for given physical parameters. The job list is used to make directories in ascending order, where each individual XSTAR is spawned on each processor and outputs are saved. HEASoft's XSTAR2TABLE program is invoked upon the contents of each directory in order to produce table model FITS files for spectroscopy analysis tools.

  6. MPI Debugging with Handle Introspection

    DEFF Research Database (Denmark)

    Brock-Nannestad, Laust; DelSignore, John; Squyres, Jeffrey M.

    The Message Passing Interface, MPI, is the standard programming model for high performance computing clusters. However, debugging applications on large scale clusters is difficult. The widely used Message Queue Dumping interface enables inspection of message queue state but there is no general in...

  7. Development of an MPI benchmark program library

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Hitoshi

    2001-03-01

    Distributed parallel simulation software with message passing interfaces has been developed to realize large-scale and high performance numerical simulations. The most popular API for message communication is an MPI. The MPI will be provided on the Earth Simulator. It is known that performance of message communication using the MPI libraries gives a significant influence on a whole performance of simulation programs. We developed an MPI benchmark program library named MBL in order to measure the performance of message communication precisely. The MBL measures the performance of major MPI functions such as point-to-point communications and collective communications and the performance of major communication patterns which are often found in application programs. In this report, the description of the MBL and the performance analysis of the MPI/SX measured on the SX-4 are presented. (author)

  8. Static Deadlock Detection in MPI Synchronization Communication

    OpenAIRE

    Ming-Xue, Liao; Xiao-Xin, He; Zhi-Hua, Fan

    2007-01-01

    It is very common to use dynamic methods to detect deadlocks in MPI programs for the reason that static methods have some restrictions. To guarantee high reliability of some important MPI-based application software, a model of MPI synchronization communication is abstracted and a type of static method is devised to examine deadlocks in such modes. The model has three forms with different complexity: sequential model, single-loop model and nested-loop model. Sequential model is a base for all ...

  9. SKaMPI: A Comprehensive Benchmark for Public Benchmarking of MPI

    Directory of Open Access Journals (Sweden)

    Ralf Reussner

    2002-01-01

    Full Text Available The main objective of the MPI communication library is to enable portable parallel programming with high performance within the message-passing paradigm. Since the MPI standard has no associated performance model, and makes no performance guarantees, comprehensive, detailed and accurate performance figures for different hardware platforms and MPI implementations are important for the application programmer, both for understanding and possibly improving the behavior of a given program on a given platform, as well as for assuring a degree of predictable behavior when switching to another hardware platform and/or MPI implementation. We term this latter goal performance portability, and address the problem of attaining performance portability by benchmarking. We describe the SKaMPI benchmark which covers a large fraction of MPI, and incorporates well-accepted mechanisms for ensuring accuracy and reliability. SKaMPI is distinguished among other MPI benchmarks by an effort to maintain a public performance database with performance data from different hardware platforms and MPI implementations.

  10. OpenMPI and ExxonMobil Topics

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Nathan Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pritchard, Howard Porter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-09

    These are a series of slides for a presentation for ExxonMobil's visit to Los Alamos National Laboratory. Topics covered are: Open MPI - The Release Story, MPI-3 RMA in Open MPI, MPI dynamic process management and Open MPI, and new options with CLE 6. Open MPI RMA features are: since v2.0.0 full support for the MPI-3.1 specification, support for non-contiguous datatypes, support for direct use of the RDMA capabilities of high performance networks (Cray Gemini/Aries, Infiniband), starting in v2.1.0 will have support for using network atomic operations for MPI_Fetch_and_op and MPI_Compare_and_swap, tested with MPI_THREAD_MULTIPLE.

  11. X-space MPI: magnetic nanoparticles for safe medical imaging.

    Science.gov (United States)

    Goodwill, Patrick William; Saritas, Emine Ulku; Croft, Laura Rose; Kim, Tyson N; Krishnan, Kannan M; Schaffer, David V; Conolly, Steven M

    2012-07-24

    One quarter of all iodinated contrast X-ray clinical imaging studies are now performed on Chronic Kidney Disease (CKD) patients. Unfortunately, the iodine contrast agent used in X-ray is often toxic to CKD patients' weak kidneys, leading to significant morbidity and mortality. Hence, we are pioneering a new medical imaging method, called Magnetic Particle Imaging (MPI), to replace X-ray and CT iodinated angiography, especially for CKD patients. MPI uses magnetic nanoparticle contrast agents that are much safer than iodine for CKD patients. MPI already offers superb contrast and extraordinary sensitivity. The iron oxide nanoparticle tracers required for MPI are also used in MRI, and some are already approved for human use, but the contrast agents are far more effective at illuminating blood vessels when used in the MPI modality. We have recently developed a systems theoretic framework for MPI called x-space MPI, which has already dramatically improved the speed and robustness of MPI image reconstruction. X-space MPI has allowed us to optimize the hardware for fi ve MPI scanners. Moreover, x-space MPI provides a powerful framework for optimizing the size and magnetic properties of the iron oxide nanoparticle tracers used in MPI. Currently MPI nanoparticles have diameters in the 10-20 nanometer range, enabling millimeter-scale resolution in small animals. X-space MPI theory predicts that larger nanoparticles could enable up to 250 micrometer resolution imaging, which would represent a major breakthrough in safe imaging for CKD patients.

  12. Final report: Compiled MPI. Cost-Effective Exascale Application Development

    Energy Technology Data Exchange (ETDEWEB)

    Gropp, William Douglas [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-12-21

    This is the final report on Compiled MPI: Cost-Effective Exascale Application Development, and summarizes the results under this project. The project investigated runtime enviroments that improve the performance of MPI (Message-Passing Interface) programs; work at Illinois in the last period of this project looked at optimizing data access optimizations expressed with MPI datatypes.

  13. MPI support in the DIRAC Pilot Job Workload Management System

    International Nuclear Information System (INIS)

    Tsaregorodtsev, A; Hamar, V

    2012-01-01

    Parallel job execution in the grid environment using MPI technology presents a number of challenges for the sites providing this support. Multiple flavors of the MPI libraries, shared working directories required by certain applications, special settings for the batch systems make the MPI support difficult for the site managers. On the other hand the workload management systems with Pilot Jobs became ubiquitous although the support for the MPI applications in the Pilot frameworks was not available. This support was recently added in the DIRAC Project in the context of the GISELA Latin American Grid Initiative. Special services for dynamic allocation of virtual computer pools on the grid sites were developed in order to deploy MPI rings corresponding to the requirements of the jobs in the central task queue of the DIRAC Workload Management System. Pilot Jobs using user space file system techniques install the required MPI software automatically. The same technique is used to emulate shared working directories for the parallel MPI processes. This makes it possible to execute MPI jobs even on the sites not supporting them officially. Reusing so constructed MPI rings for execution of a series of parallel jobs increases dramatically their efficiency and turnaround. In this contribution we describe the design and implementation of the DIRAC MPI Service as well as its support for various types of MPI libraries. Advantages of coupling the MPI support with the Pilot frameworks are outlined and examples of usage with real applications are presented.

  14. DISP: Optimizations towards Scalable MPI Startup

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Huansong [Florida State University, Tallahassee; Pophale, Swaroop S [ORNL; Gorentla Venkata, Manjunath [ORNL; Yu, Weikuan [Florida State University, Tallahassee

    2016-01-01

    Despite the popularity of MPI for high performance computing, the startup of MPI programs faces a scalability challenge as both the execution time and memory consumption increase drastically at scale. We have examined this problem using the collective modules of Cheetah and Tuned in Open MPI as representative implementations. Previous improvements for collectives have focused on algorithmic advances and hardware off-load. In this paper, we examine the startup cost of the collective module within a communicator and explore various techniques to improve its efficiency and scalability. Accordingly, we have developed a new scalable startup scheme with three internal techniques, namely Delayed Initialization, Module Sharing and Prediction-based Topology Setup (DISP). Our DISP scheme greatly benefits the collective initialization of the Cheetah module. At the same time, it helps boost the performance of non-collective initialization in the Tuned module. We evaluate the performance of our implementation on Titan supercomputer at ORNL with up to 4096 processes. The results show that our delayed initialization can speed up the startup of Tuned and Cheetah by an average of 32.0% and 29.2%, respectively, our module sharing can reduce the memory consumption of Tuned and Cheetah by up to 24.1% and 83.5%, respectively, and our prediction-based topology setup can speed up the startup of Cheetah by up to 80%.

  15. MPI_XSTAR: MPI-based Parallelization of the XSTAR Photoionization Program

    Science.gov (United States)

    Danehkar, Ashkbiz; Nowak, Michael A.; Lee, Julia C.; Smith, Randall K.

    2018-02-01

    We describe a program for the parallel implementation of multiple runs of XSTAR, a photoionization code that is used to predict the physical properties of an ionized gas from its emission and/or absorption lines. The parallelization program, called MPI_XSTAR, has been developed and implemented in the C++ language by using the Message Passing Interface (MPI) protocol, a conventional standard of parallel computing. We have benchmarked parallel multiprocessing executions of XSTAR, using MPI_XSTAR, against a serial execution of XSTAR, in terms of the parallelization speedup and the computing resource efficiency. Our experience indicates that the parallel execution runs significantly faster than the serial execution, however, the efficiency in terms of the computing resource usage decreases with increasing the number of processors used in the parallel computing.

  16. MPI-AMRVAC FOR SOLAR AND ASTROPHYSICS

    Energy Technology Data Exchange (ETDEWEB)

    Porth, O. [Department of Applied Mathematics, The University of Leeds, Leeds LS2 9JT (United Kingdom); Xia, C.; Hendrix, T.; Moschou, S. P.; Keppens, R., E-mail: o.porth@leeds.ac.uk [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

    2014-09-01

    In this paper, we present an update to the open source MPI-AMRVAC simulation toolkit where we focus on solar and non-relativistic astrophysical magnetofluid dynamics. We highlight recent developments in terms of physics modules, such as hydrodynamics with dust coupling and the conservative implementation of Hall magnetohydrodynamics. A simple conservative high-order finite difference scheme that works in combination with all available physics modules is introduced and demonstrated with the example of monotonicity-preserving fifth-order reconstruction. Strong stability-preserving high-order Runge-Kutta time steppers are used to obtain stable evolutions in multi-dimensional applications, realizing up to fourth-order accuracy in space and time. With the new distinction between active and passive grid cells, MPI-AMRVAC is ideally suited to simulate evolutions where parts of the solution are controlled analytically or have a tendency to progress into or out of a stationary state. Typical test problems and representative applications are discussed with an outlook toward follow-up research. Finally, we discuss the parallel scaling of the code and demonstrate excellent weak scaling up to 30, 000 processors, allowing us to exploit modern peta-scale infrastructure.

  17. Automatic Migration from PARMACS to MPI in Parallel Fortran Applications

    Directory of Open Access Journals (Sweden)

    Rolf Hempel

    1999-01-01

    Full Text Available The PARMACS message passing interface has been in widespread use by application projects, especially in Europe. With the new MPI standard for message passing, many projects face the problem of replacing PARMACS with MPI. An automatic translation tool has been developed which replaces all PARMACS 6.0 calls in an application program with their corresponding MPI calls. In this paper we describe the mapping of the PARMACS programming model onto MPI. We then present some implementation details of the converter tool.

  18. Parallelizing AT with MatlabMPI

    International Nuclear Information System (INIS)

    2011-01-01

    The Accelerator Toolbox (AT) is a high-level collection of tools and scripts specifically oriented toward solving problems dealing with computational accelerator physics. It is integrated into the MATLAB environment, which provides an accessible, intuitive interface for accelerator physicists, allowing researchers to focus the majority of their efforts on simulations and calculations, rather than programming and debugging difficulties. Efforts toward parallelization of AT have been put in place to upgrade its performance to modern standards of computing. We utilized the packages MatlabMPI and pMatlab, which were developed by MIT Lincoln Laboratory, to set up a message-passing environment that could be called within MATLAB, which set up the necessary pre-requisites for multithread processing capabilities. On local quad-core CPUs, we were able to demonstrate processor efficiencies of roughly 95% and speed increases of nearly 380%. By exploiting the efficacy of modern-day parallel computing, we were able to demonstrate incredibly efficient speed increments per processor in AT's beam-tracking functions. Extrapolating from prediction, we can expect to reduce week-long computation runtimes to less than 15 minutes. This is a huge performance improvement and has enormous implications for the future computing power of the accelerator physics group at SSRL. However, one of the downfalls of parringpass is its current lack of transparency; the pMatlab and MatlabMPI packages must first be well-understood by the user before the system can be configured to run the scripts. In addition, the instantiation of argument parameters requires internal modification of the source code. Thus, parringpass, cannot be directly run from the MATLAB command line, which detracts from its flexibility and user-friendliness. Future work in AT's parallelization will focus on development of external functions and scripts that can be called from within MATLAB and configured on multiple nodes, while

  19. Design of Superparamagnetic Nanoparticles for Magnetic Particle Imaging (MPI

    Directory of Open Access Journals (Sweden)

    Philip W. T. Pong

    2013-09-01

    Full Text Available Magnetic particle imaging (MPI is a promising medical imaging technique producing quantitative images of the distribution of tracer materials (superparamagnetic nanoparticles without interference from the anatomical background of the imaging objects (either phantoms or lab animals. Theoretically, the MPI platform can image with relatively high temporal and spatial resolution and sensitivity. In practice, the quality of the MPI images hinges on both the applied magnetic field and the properties of the tracer nanoparticles. Langevin theory can model the performance of superparamagnetic nanoparticles and predict the crucial influence of nanoparticle core size on the MPI signal. In addition, the core size distribution, anisotropy of the magnetic core and surface modification of the superparamagnetic nanoparticles also determine the spatial resolution and sensitivity of the MPI images. As a result, through rational design of superparamagnetic nanoparticles, the performance of MPI could be effectively optimized. In this review, the performance of superparamagnetic nanoparticles in MPI is investigated. Rational synthesis and modification of superparamagnetic nanoparticles are discussed and summarized. The potential medical application areas for MPI, including cardiovascular system, oncology, stem cell tracking and immune related imaging are also analyzed and forecasted.

  20. Benchmarking MILC code with OpenMP and MPI

    International Nuclear Information System (INIS)

    Gottlieb, Steven; Tamhankar, Sonali

    2001-01-01

    A trend in high performance computers that is becoming increasingly popular is the use of symmetric multi-processing (SMP) rather than the older paradigm of MPP. MPI codes that ran and scaled well on MPP machines can often be run on an SMP machine using the vendor's version of MPI. However, this approach may not make optimal use of the (expensive) SMP hardware. More significantly, there are machines like Blue Horizon, an IBM SP with 8-way SMP nodes at the San Diego Supercomputer Center that can only support 4 MPI processes per node (with the current switch). On such a machine it is imperative to be able to use OpenMP parallelism on the node, and MPI between nodes. We describe the challenges of converting MILC MPI code to using a second level of OpenMP parallelism, and benchmarks on IBM and Sun computers

  1. Towards deductive verification of MPI programs against session types

    Directory of Open Access Journals (Sweden)

    Eduardo R. B. Marques

    2013-12-01

    Full Text Available The Message Passing Interface (MPI is the de facto standard message-passing infrastructure for developing parallel applications. Two decades after the first version of the library specification, MPI-based applications are nowadays routinely deployed on super and cluster computers. These applications, written in C or Fortran, exhibit intricate message passing behaviours, making it hard to statically verify important properties such as the absence of deadlocks. Our work builds on session types, a theory for describing protocols that provides for correct-by-construction guarantees in this regard. We annotate MPI primitives and C code with session type contracts, written in the language of a software verifier for C. Annotated code is then checked for correctness with the software verifier. We present preliminary results and discuss the challenges that lie ahead for verifying realistic MPI program compliance against session types.

  2. Memory Compression Techniques for Network Address Management in MPI

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yanfei; Archer, Charles J.; Blocksome, Michael; Parker, Scott; Bland, Wesley; Raffenetti, Ken; Balaji, Pavan

    2017-05-29

    MPI allows applications to treat processes as a logical collection of integer ranks for each MPI communicator, while internally translating these logical ranks into actual network addresses. In current MPI implementations the management and lookup of such network addresses use memory sizes that are proportional to the number of processes in each communicator. In this paper, we propose a new mechanism, called AV-Rankmap, for managing such translation. AV-Rankmap takes advantage of logical patterns in rank-address mapping that most applications naturally tend to have, and it exploits the fact that some parts of network address structures are naturally more performance critical than others. It uses this information to compress the memory used for network address management. We demonstrate that AV-Rankmap can achieve performance similar to or better than that of other MPI implementations while using significantly less memory.

  3. Development of Mixed Mode MPI / OpenMP Applications

    Directory of Open Access Journals (Sweden)

    Lorna Smith

    2001-01-01

    Full Text Available MPI / OpenMP mixed mode codes could potentially offer the most effective parallelisation strategy for an SMP cluster, as well as allowing the different characteristics of both paradigms to be exploited to give the best performance on a single SMP. This paper discusses the implementation, development and performance of mixed mode MPI / OpenMP applications. The results demonstrate that this style of programming will not always be the most effective mechanism on SMP systems and cannot be regarded as the ideal programming model for all codes. In some situations, however, significant benefit may be obtained from a mixed mode implementation. For example, benefit may be obtained if the parallel (MPI code suffers from: poor scaling with MPI processes due to load imbalance or too fine a grain problem size, memory limitations due to the use of a replicated data strategy, or a restriction on the number of MPI processes combinations. In addition, if the system has a poorly optimised or limited scaling MPI implementation then a mixed mode code may increase the code performance.

  4. Practical Formal Verification of MPI and Thread Programs

    Science.gov (United States)

    Gopalakrishnan, Ganesh; Kirby, Robert M.

    Large-scale simulation codes in science and engineering are written using the Message Passing Interface (MPI). Shared memory threads are widely used directly, or to implement higher level programming abstractions. Traditional debugging methods for MPI or thread programs are incapable of providing useful formal guarantees about coverage. They get bogged down in the sheer number of interleavings (schedules), often missing shallow bugs. In this tutorial we will introduce two practical formal verification tools: ISP (for MPI C programs) and Inspect (for Pthread C programs). Unlike other formal verification tools, ISP and Inspect run directly on user source codes (much like a debugger). They pursue only the relevant set of process interleavings, using our own customized Dynamic Partial Order Reduction algorithms. For a given test harness, DPOR allows these tools to guarantee the absence of deadlocks, instrumented MPI object leaks and communication races (using ISP), and shared memory races (using Inspect). ISP and Inspect have been used to verify large pieces of code: in excess of 10,000 lines of MPI/C for ISP in under 5 seconds, and about 5,000 lines of Pthread/C code in a few hours (and much faster with the use of a cluster or by exploiting special cases such as symmetry) for Inspect. We will also demonstrate the Microsoft Visual Studio and Eclipse Parallel Tools Platform integrations of ISP (these will be available on the LiveCD).

  5. What does fault tolerant Deep Learning need from MPI?

    Energy Technology Data Exchange (ETDEWEB)

    Amatya, Vinay C.; Vishnu, Abhinav; Siegel, Charles M.; Daily, Jeffrey A.

    2017-09-25

    Deep Learning (DL) algorithms have become the {\\em de facto} Machine Learning (ML) algorithm for large scale data analysis. DL algorithms are computationally expensive -- even distributed DL implementations which use MPI require days of training (model learning) time on commonly studied datasets. Long running DL applications become susceptible to faults -- requiring development of a fault tolerant system infrastructure, in addition to fault tolerant DL algorithms. This raises an important question: {\\em What is needed from MPI for designing fault tolerant DL implementations?} In this paper, we address this problem for permanent faults. We motivate the need for a fault tolerant MPI specification by an in-depth consideration of recent innovations in DL algorithms and their properties, which drive the need for specific fault tolerance features. We present an in-depth discussion on the suitability of different parallelism types (model, data and hybrid); a need (or lack thereof) for check-pointing of any critical data structures; and most importantly, consideration for several fault tolerance proposals (user-level fault mitigation (ULFM), Reinit) in MPI and their applicability to fault tolerant DL implementations. We leverage a distributed memory implementation of Caffe, currently available under the Machine Learning Toolkit for Extreme Scale (MaTEx). We implement our approaches by extending MaTEx-Caffe for using ULFM-based implementation. Our evaluation using the ImageNet dataset and AlexNet neural network topology demonstrates the effectiveness of the proposed fault tolerant DL implementation using OpenMPI based ULFM.

  6. Computational mathematics models, methods, and analysis with Matlab and MPI

    CERN Document Server

    White, Robert E

    2004-01-01

    Computational Mathematics: Models, Methods, and Analysis with MATLAB and MPI explores and illustrates this process. Each section of the first six chapters is motivated by a specific application. The author applies a model, selects a numerical method, implements computer simulations, and assesses the ensuing results. These chapters include an abundance of MATLAB code. By studying the code instead of using it as a "black box, " you take the first step toward more sophisticated numerical modeling. The last four chapters focus on multiprocessing algorithms implemented using message passing interface (MPI). These chapters include Fortran 9x codes that illustrate the basic MPI subroutines and revisit the applications of the previous chapters from a parallel implementation perspective. All of the codes are available for download from www4.ncsu.edu./~white.This book is not just about math, not just about computing, and not just about applications, but about all three--in other words, computational science. Whether us...

  7. Overlapping Communication and Computation with OpenMP and MPI

    Directory of Open Access Journals (Sweden)

    Timothy H. Kaiser

    2001-01-01

    Full Text Available Machines comprised of a distributed collection of shared memory or SMP nodes are becoming common for parallel computing. OpenMP can be combined with MPI on many such machines. Motivations for combing OpenMP and MPI are discussed. While OpenMP is typically used for exploiting loop-level parallelism it can also be used to enable coarse grain parallelism, potentially leading to less overhead. We show how coarse grain OpenMP parallelism can also be used to facilitate overlapping MPI communication and computation for stencil-based grid programs such as a program performing Gauss-Seidel iteration with red-black ordering. Spatial subdivision or domain decomposition is used to assign a portion of the grid to each thread. One thread is assigned a null calculation region so it was free to perform communication. Example calculations were run on an IBM SP using both the Kuck & Associates and IBM compilers.

  8. Power-aware load balancing of large scale MPI applications

    OpenAIRE

    Etinski, Maja; Corbalán González, Julita; Labarta Mancho, Jesús José; Valero Cortés, Mateo; Veidenbaum, Alex

    2009-01-01

    Power consumption is a very important issue for HPC community, both at the level of one application or at the level of whole workload. Load imbalance of a MPI application can be exploited to save CPU energy without penalizing the execution time. An application is load imbalanced when some nodes are assigned more computation than others. The nodes with less computation can be run at lower frequency since otherwise they have to wait for the nodes with more computation blocked in MPI calls. A te...

  9. Compiled MPI: Cost-Effective Exascale Applications Development

    Energy Technology Data Exchange (ETDEWEB)

    Bronevetsky, G; Quinlan, D; Lumsdaine, A; Hoefler, T

    2012-04-10

    The complexity of petascale and exascale machines makes it increasingly difficult to develop applications that can take advantage of them. Future systems are expected to feature billion-way parallelism, complex heterogeneous compute nodes and poor availability of memory (Peter Kogge, 2008). This new challenge for application development is motivating a significant amount of research and development on new programming models and runtime systems designed to simplify large-scale application development. Unfortunately, DoE has significant multi-decadal investment in a large family of mission-critical scientific applications. Scaling these applications to exascale machines will require a significant investment that will dwarf the costs of hardware procurement. A key reason for the difficulty in transitioning today's applications to exascale hardware is their reliance on explicit programming techniques, such as the Message Passing Interface (MPI) programming model to enable parallelism. MPI provides a portable and high performance message-passing system that enables scalable performance on a wide variety of platforms. However, it also forces developers to lock the details of parallelization together with application logic, making it very difficult to adapt the application to significant changes in the underlying system. Further, MPI's explicit interface makes it difficult to separate the application's synchronization and communication structure, reducing the amount of support that can be provided by compiler and run-time tools. This is in contrast to the recent research on more implicit parallel programming models such as Chapel, OpenMP and OpenCL, which promise to provide significantly more flexibility at the cost of reimplementing significant portions of the application. We are developing CoMPI, a novel compiler-driven approach to enable existing MPI applications to scale to exascale systems with minimal modifications that can be made incrementally over

  10. The particular prediction of normal MPI in diabetic patients

    International Nuclear Information System (INIS)

    Wu, Z.-F.; Li, S.-J.; Liu, H.-Y.; Liu, J.Z.; Li, X.F.; Cheng, Y.; Zhang, Y.W.; Wang, J.

    2007-01-01

    Full text: Objectives: To explore the prognostic value of normal SPECT MPI in diabetic pts. Methods: 1371 consecutively registered pts suspected with CAD were studied using rest SPECT MPI, and 1047 cases (76.37%) were followed up successfully. The mean interval of following up was 33.25±14.95(1∼56) months, and even longer than 18 months for pts with no cardiac events (CE). Results: Of 1047 pts, 172 were diabetic. During the follow up period, there are 42 cardiac events in 172 diabetic patients, and 86 in 857 non-diabetics. Diabetic pts had significantly higher rates of cardiac events (24.4% versus 9.8%; chi-square 28.5, P<0.0001). In the 567 pts with normal MPI, there are 4 cardiac events in 54 diabetic pts and 6 cases in 513 nondiabetic pts. The diabetic pts had significantly higher rates of cardiac events compared with the non-diabetic pts (7.41% versus 1.17%, Fisher's Exact Test, P=0.01). Conclusions: A normal SPECT has a high negative predictive value, but diabetic patients had significantly higher cardiac events rate compared with non-diabetic patients, what ever the MPI is normal or abnormal. (author)

  11. 32 CFR 637.8 - Identification of MPI.

    Science.gov (United States)

    2010-07-01

    ... CRIMINAL INVESTIGATIONS MILITARY POLICE INVESTIGATION Investigations § 637.8 Identification of MPI. (a... referring to themselves as “INVESTIGATOR.” When signing military police records the title “Military Police Investigator” may be used in lieu of military titles. Civilian personnel will refer to themselves as...

  12. Fenix, A Fault Tolerant Programming Framework for MPI Applications

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-05

    Fenix provides APIs to allow the users to add fault tolerance capability to MPI-based parallel programs in a transparent manner. Fenix-enabled programs can run through process failures during program execution using a pool of spare processes accommodated by Fenix.

  13. Fault Tolerance Assistant (FTA): An Exception Handling Programming Model for MPI Applications

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Aiman [Univ. of Chicago, IL (United States). Dept. of Computer Science; Laguna, Ignacio [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sato, Kento [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Islam, Tanzima [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mohror, Kathryn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-23

    Future high-performance computing systems may face frequent failures with their rapid increase in scale and complexity. Resilience to faults has become a major challenge for large-scale applications running on supercomputers, which demands fault tolerance support for prevalent MPI applications. Among failure scenarios, process failures are one of the most severe issues as they usually lead to termination of applications. However, the widely used MPI implementations do not provide mechanisms for fault tolerance. We propose FTA-MPI (Fault Tolerance Assistant MPI), a programming model that provides support for failure detection, failure notification and recovery. Specifically, FTA-MPI exploits a try/catch model that enables failure localization and transparent recovery of process failures in MPI applications. We demonstrate FTA-MPI with synthetic applications and a molecular dynamics code CoMD, and show that FTA-MPI provides high programmability for users and enables convenient and flexible recovery of process failures.

  14. Coupling of THALES and FROST using MPI Method

    International Nuclear Information System (INIS)

    Park, Jin Woo; Ryu, Seok Hee; Jung, Chan Do; Jung, Jee Hoon; Um, Kil Sup; Lee, Jae Il

    2013-01-01

    This paper presents the coupling method between THALES and FROST and the simulation results with the coupled code system. In this study, subchannel analysis code THALES and transient fuel performance code FROST were coupled using MPI method as the first stage of the development of the multi-dimensional safety analysis methodology. As a part of the validation, the CEA ejection accident was simulated using the coupled THALES-FROST code and the results were compared with the ShinKori 3 and 4 FSAR. Comparison results revealed that CHASER using MPI method predicts fuel temperatures and heat flux quantitatively well. Thus it was confirmed that the THALES and FROST are properly coupled. In near future, ASTRA, multi-dimensional core neutron kinetics code, will be linked to THALESFROST code for the detailed three-dimensional CEA ejection analysis. The current safety analysis methodology for a CEA ejection accident based on numerous conservative assumptions with the point kinetics model results in quite adverse consequences. Thus, KNF is developing the multi-dimensional safety analysis methodology to enhance the consequences of the CEA ejection accident. For this purpose, three-dimensional core neutron kinetics code ASTRA, subchannel analysis code THALES, and transient fuel performance analysis code FROST are being coupled using message passing interface(MPI). For the first step, THALES and FROST are coupled and tested

  15. Hybrid x-space: a new approach for MPI reconstruction.

    Science.gov (United States)

    Tateo, A; Iurino, A; Settanni, G; Andrisani, A; Stifanelli, P F; Larizza, P; Mazzia, F; Mininni, R M; Tangaro, S; Bellotti, R

    2016-06-07

    Magnetic particle imaging (MPI) is a new medical imaging technique capable of recovering the distribution of superparamagnetic particles from their measured induced signals. In literature there are two main MPI reconstruction techniques: measurement-based (MB) and x-space (XS). The MB method is expensive because it requires a long calibration procedure as well as a reconstruction phase that can be numerically costly. On the other side, the XS method is simpler than MB but the exact knowledge of the field free point (FFP) motion is essential for its implementation. Our simulation work focuses on the implementation of a new approach for MPI reconstruction: it is called hybrid x-space (HXS), representing a combination of the previous methods. Specifically, our approach is based on XS reconstruction because it requires the knowledge of the FFP position and velocity at each time instant. The difference with respect to the original XS formulation is how the FFP velocity is computed: we estimate it from the experimental measurements of the calibration scans, typical of the MB approach. Moreover, a compressive sensing technique is applied in order to reduce the calibration time, setting a fewer number of sampling positions. Simulations highlight that HXS and XS methods give similar results. Furthermore, an appropriate use of compressive sensing is crucial for obtaining a good balance between time reduction and reconstructed image quality. Our proposal is suitable for open geometry configurations of human size devices, where incidental factors could make the currents, the fields and the FFP trajectory irregular.

  16. Experiences implementing the MPI standard on Sandia`s lightweight kernels

    Energy Technology Data Exchange (ETDEWEB)

    Brightwell, R.; Greenberg, D.S.

    1997-10-01

    This technical report describes some lessons learned from implementing the Message Passing Interface (MPI) standard, and some proposed extentions to MPI, at Sandia. The implementations were developed using Sandia-developed lightweight kernels running on the Intel Paragon and Intel TeraFLOPS platforms. The motivations for this research are discussed, and a detailed analysis of several implementation issues is presented.

  17. High-Level Topology-Oblivious Optimization of MPI Broadcast Algorithms on Extreme-Scale Platforms

    KAUST Repository

    Hasanov, Khalid; Quintin, Jean-Noë l; Lastovetsky, Alexey

    2014-01-01

    by taking into account either their topology or platform parameters. In this work we propose a very simple and at the same time general approach to optimize legacy MPI broadcast algorithms, which are widely used in MPICH and OpenMPI. Theoretical analysis

  18. Implementation and validation of a model of the MPI Stewart platform

    NARCIS (Netherlands)

    Nieuwenhuizen, F.M.; Van Paasen, M.M.; Mulder, M.; Bülthoff, H.H.

    2010-01-01

    A simulated model of the MPI Stewart platform can be used to identify the influence of motion system characteristics on human control behaviour in active closed-loop control experiments on the SIMONA Research Simulator. In this paper, a previously identified model of the MPI Stewart platform was

  19. Evaluation of iron oxide nanoparticle micelles for Magnetic Particle Imaging (MPI) of thrombosis

    NARCIS (Netherlands)

    Starmans, L.W.E.; Moonen, R.P.M.; Aussems-Custers, E.; Daemen, M.J.A.P.; Strijkers, G. J.; Nicolay, K.; Grüll, H.

    2015-01-01

    Magnetic particle imaging (MPI) is an emerging medical imaging modality that directly visualizes magnetic particles in a hot-spot like fashion. We recently developed an iron oxide nanoparticle-micelle (ION-Micelle) platform that allows highly sensitive MPI. The goal of this study was to assess the

  20. Scalable High Performance Message Passing over InfiniBand for Open MPI

    Energy Technology Data Exchange (ETDEWEB)

    Friedley, A; Hoefler, T; Leininger, M L; Lumsdaine, A

    2007-10-24

    InfiniBand (IB) is a popular network technology for modern high-performance computing systems. MPI implementations traditionally support IB using a reliable, connection-oriented (RC) transport. However, per-process resource usage that grows linearly with the number of processes, makes this approach prohibitive for large-scale systems. IB provides an alternative in the form of a connectionless unreliable datagram transport (UD), which allows for near-constant resource usage and initialization overhead as the process count increases. This paper describes a UD-based implementation for IB in Open MPI as a scalable alternative to existing RC-based schemes. We use the software reliability capabilities of Open MPI to provide the guaranteed delivery semantics required by MPI. Results show that UD not only requires fewer resources at scale, but also allows for shorter MPI startup times. A connectionless model also improves performance for applications that tend to send small messages to many different processes.

  1. SBML-PET-MPI: a parallel parameter estimation tool for Systems Biology Markup Language based models.

    Science.gov (United States)

    Zi, Zhike

    2011-04-01

    Parameter estimation is crucial for the modeling and dynamic analysis of biological systems. However, implementing parameter estimation is time consuming and computationally demanding. Here, we introduced a parallel parameter estimation tool for Systems Biology Markup Language (SBML)-based models (SBML-PET-MPI). SBML-PET-MPI allows the user to perform parameter estimation and parameter uncertainty analysis by collectively fitting multiple experimental datasets. The tool is developed and parallelized using the message passing interface (MPI) protocol, which provides good scalability with the number of processors. SBML-PET-MPI is freely available for non-commercial use at http://www.bioss.uni-freiburg.de/cms/sbml-pet-mpi.html or http://sites.google.com/site/sbmlpetmpi/.

  2. Psychometric evaluation of the Spanish version of the MPI-SCI.

    Science.gov (United States)

    Soler, M D; Cruz-Almeida, Y; Saurí, J; Widerström-Noga, E G

    2013-07-01

    Postal surveys. To confirm the factor structure of the Spanish version of the MPI-SCI (MPI-SCI-S, Multidimensional Pain Inventory in the SCI population) and to test its internal consistency and construct validity in a Spanish population. Guttmann Institute, Barcelona, Spain. The MPI-SCI-S along with Spanish measures of pain intensity (Numerical Rating Scale), pain interference (Brief Pain Inventory), functional independence (Functional Independence Measure), depression (Beck Depression Inventory), locus of control (Multidimensional health Locus of Control), support (Functional Social Support Questionnaire (Duke-UNC)), psychological well-being (Psychological Global Well-Being Index) and demographic/injury characteristics were assessed in persons with spinal cord injury (SCI) and chronic pain (n=126). Confirmatory factor analysis suggested an adequate factor structure for the MPI-SCI-S. The internal consistency of the MPI-SCI-S subscales ranged from acceptable (r=0.66, Life Control) to excellent (r=0.94, Life Interference). All MPI-SCI-S subscales showed adequate construct validity, with the exception of the Negative and Solicitous Responses subscales. The Spanish version of the MPI-SCI is adequate for evaluating chronic pain impact following SCI in a Spanish-speaking population. Future studies should include additional measures of pain-related support in the Spanish-speaking SCI population.

  3. Parallel MCNP Monte Carlo transport calculations with MPI

    International Nuclear Information System (INIS)

    Wagner, J.C.; Haghighat, A.

    1996-01-01

    The steady increase in computational performance has made Monte Carlo calculations for large/complex systems possible. However, in order to make these calculations practical, order of magnitude increases in performance are necessary. The Monte Carlo method is inherently parallel (particles are simulated independently) and thus has the potential for near-linear speedup with respect to the number of processors. Further, the ever-increasing accessibility of parallel computers, such as workstation clusters, facilitates the practical use of parallel Monte Carlo. Recognizing the nature of the Monte Carlo method and the trends in available computing, the code developers at Los Alamos National Laboratory implemented the message-passing general-purpose Monte Carlo radiation transport code MCNP (version 4A). The PVM package was chosen by the MCNP code developers because it supports a variety of communication networks, several UNIX platforms, and heterogeneous computer systems. This PVM version of MCNP has been shown to produce speedups that approach the number of processors and thus, is a very useful tool for transport analysis. Due to software incompatibilities on the local IBM SP2, PVM has not been available, and thus it is not possible to take advantage of this useful tool. Hence, it became necessary to implement an alternative message-passing library package into MCNP. Because the message-passing interface (MPI) is supported on the local system, takes advantage of the high-speed communication switches in the SP2, and is considered to be the emerging standard, it was selected

  4. High-Level Topology-Oblivious Optimization of MPI Broadcast Algorithms on Extreme-Scale Platforms

    KAUST Repository

    Hasanov, Khalid

    2014-01-01

    There has been a significant research in collective communication operations, in particular in MPI broadcast, on distributed memory platforms. Most of the research works are done to optimize the collective operations for particular architectures by taking into account either their topology or platform parameters. In this work we propose a very simple and at the same time general approach to optimize legacy MPI broadcast algorithms, which are widely used in MPICH and OpenMPI. Theoretical analysis and experimental results on IBM BlueGene/P and a cluster of Grid’5000 platform are presented.

  5. MPI to Coarray Fortran: Experiences with a CFD Solver for Unstructured Meshes

    Directory of Open Access Journals (Sweden)

    Anuj Sharma

    2017-01-01

    Full Text Available High-resolution numerical methods and unstructured meshes are required in many applications of Computational Fluid Dynamics (CFD. These methods are quite computationally expensive and hence benefit from being parallelized. Message Passing Interface (MPI has been utilized traditionally as a parallelization strategy. However, the inherent complexity of MPI contributes further to the existing complexity of the CFD scientific codes. The Partitioned Global Address Space (PGAS parallelization paradigm was introduced in an attempt to improve the clarity of the parallel implementation. We present our experiences of converting an unstructured high-resolution compressible Navier-Stokes CFD solver from MPI to PGAS Coarray Fortran. We present the challenges, methodology, and performance measurements of our approach using Coarray Fortran. With the Cray compiler, we observe Coarray Fortran as a viable alternative to MPI. We are hopeful that Intel and open-source implementations could be utilized in the future.

  6. Topology-oblivious optimization of MPI broadcast algorithms on extreme-scale platforms

    KAUST Repository

    Hasanov, Khalid; Quintin, Jean-Noë l; Lastovetsky, Alexey

    2015-01-01

    operations for particular architectures by taking into account either their topology or platform parameters. In this work we propose a simple but general approach to optimization of the legacy MPI broadcast algorithms, which are widely used in MPICH and Open

  7. Cell verification of parallel burnup calculation program MCBMPI based on MPI

    International Nuclear Information System (INIS)

    Yang Wankui; Liu Yaoguang; Ma Jimin; Wang Guanbo; Yang Xin; She Ding

    2014-01-01

    The parallel burnup calculation program MCBMPI was developed. The program was modularized. The parallel MCNP5 program MCNP5MPI was employed as neutron transport calculation module. And a composite of three solution methods was used to solve burnup equation, i.e. matrix exponential technique, TTA analytical solution, and Gauss Seidel iteration. MPI parallel zone decomposition strategy was concluded in the program. The program system only consists of MCNP5MPI and burnup subroutine. The latter achieves three main functions, i.e. zone decomposition, nuclide transferring and decaying, and data exchanging with MCNP5MPI. Also, the program was verified with the pressurized water reactor (PWR) cell burnup benchmark. The results show that it,s capable to apply the program to burnup calculation of multiple zones, and the computation efficiency could be significantly improved with the development of computer hardware. (authors)

  8. Specification of Fenix MPI Fault Tolerance library version 1.0.1

    Energy Technology Data Exchange (ETDEWEB)

    Gamble, Marc [Rutgers Univ., New Brunswick, NJ (United States); Van Der Wijngaart, Rob [Intel Corps., Mountain View, CA (United States); Teranishi, Keita [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Parashar, Manish [Rutgers Univ., New Brunswick, NJ (United States)

    2016-10-01

    This document provides a specification of Fenix, a software library compatible with the Message Passing Interface (MPI) to support fault recovery without application shutdown. The library consists of two modules. The first, termed process recovery , restores an application to a consistent state after it has suffered a loss of one or more MPI processes (ranks). The second specifies functions the user can invoke to store application data in Fenix managed redundant storage, and to retrieve it from that storage after process recovery.

  9. Performance modeling of hybrid MPI/OpenMP scientific applications on large-scale multicore supercomputers

    KAUST Repository

    Wu, Xingfu; Taylor, Valerie

    2013-01-01

    In this paper, we present a performance modeling framework based on memory bandwidth contention time and a parameterized communication model to predict the performance of OpenMP, MPI and hybrid applications with weak scaling on three large-scale multicore supercomputers: IBM POWER4, POWER5+ and BlueGene/P, and analyze the performance of these MPI, OpenMP and hybrid applications. We use STREAM memory benchmarks and Intel's MPI benchmarks to provide initial performance analysis and model validation of MPI and OpenMP applications on these multicore supercomputers because the measured sustained memory bandwidth can provide insight into the memory bandwidth that a system should sustain on scientific applications with the same amount of workload per core. In addition to using these benchmarks, we also use a weak-scaling hybrid MPI/OpenMP large-scale scientific application: Gyrokinetic Toroidal Code (GTC) in magnetic fusion to validate our performance model of the hybrid application on these multicore supercomputers. The validation results for our performance modeling method show less than 7.77% error rate in predicting the performance of hybrid MPI/OpenMP GTC on up to 512 cores on these multicore supercomputers. © 2013 Elsevier Inc.

  10. Performance modeling of hybrid MPI/OpenMP scientific applications on large-scale multicore supercomputers

    KAUST Repository

    Wu, Xingfu

    2013-12-01

    In this paper, we present a performance modeling framework based on memory bandwidth contention time and a parameterized communication model to predict the performance of OpenMP, MPI and hybrid applications with weak scaling on three large-scale multicore supercomputers: IBM POWER4, POWER5+ and BlueGene/P, and analyze the performance of these MPI, OpenMP and hybrid applications. We use STREAM memory benchmarks and Intel\\'s MPI benchmarks to provide initial performance analysis and model validation of MPI and OpenMP applications on these multicore supercomputers because the measured sustained memory bandwidth can provide insight into the memory bandwidth that a system should sustain on scientific applications with the same amount of workload per core. In addition to using these benchmarks, we also use a weak-scaling hybrid MPI/OpenMP large-scale scientific application: Gyrokinetic Toroidal Code (GTC) in magnetic fusion to validate our performance model of the hybrid application on these multicore supercomputers. The validation results for our performance modeling method show less than 7.77% error rate in predicting the performance of hybrid MPI/OpenMP GTC on up to 512 cores on these multicore supercomputers. © 2013 Elsevier Inc.

  11. Proceedings of the first international workshop on multiple partonic interactions at the LHC. MPI'08

    Energy Technology Data Exchange (ETDEWEB)

    Bartalini, Paolo [National Taiwan Univ., Taipei (China); Fano, Livio [Istituto Nazionale di Fisica Nucleare, Perugia (Italy)

    2009-06-15

    The objective of this first workshop on Multiple Partonic Interactions (MPI) at the LHC, that can be regarded as a continuation and extension of the dedicated meetings held at DESY in the years 2006 and 2007, is to raise the profile of MPI studies, summarizing the legacy from the older phenomenology at hadronic colliders and favouring further specific contacts between the theory and experimental communities. The MPI are experiencing a growing popularity and are currently widely invoked to account for observations that would not be explained otherwise: the activity of the Underlying Event, the cross sections for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. At the same time, the implementation of the MPI effects in the Monte Carlo models is quickly proceeding through an increasing level of sophistication and complexity that in perspective achieves deep general implications for the LHC physics. The ultimate ambition of this workshop is to promote the MPI as unification concept between seemingly heterogeneous research lines and to profit of the complete experimental picture in order to constrain their implementation in the models, evaluating the spin offs on the LHC physics program. The workshop is structured in five sections, with the first one dedicated to few selected hot highlights in the High Energy Physics and directly connected to the other ones: Multiple Parton Interactions (in both the soft and the hard regimes), Diffraction, Monte Carlo Generators and Heavy Ions. (orig.)

  12. Safety and efficacy of Regadenoson in myocardial perfusion imaging (MPI) stress tests: A review

    Science.gov (United States)

    Ahmed, Ambereen

    2018-02-01

    Myocardial perfusion imaging (MPI) tests are often used to help diagnose coronary heart disease (CAD). The tests usually involve applying stress, such as hard physical exercise together with administration of vasodilators, to the patients. To date, many of these tests use non-selective A2A adenosine receptor agonists which, however, can be associated with highly undesirable and life-threatening side effects such as chest pain, dyspnea, severe bronchoconstriction and atrioventricular conduction anomalies. Regadenoson is a relatively new, highly selective A2A adenosine receptor agonist, suitable for use in MPI tests which exhibits far fewer adverse side effects and, unlike others testing agents, can be used without the necessity of excessive concomitant exercise. Also, the dose of regadenoson required is not dependent upon patient weight or renal impairment, and it can be rapidly administered by i.v. Injection. Regadenoson use in MPI testing thus has the potential as a simplified, relatively safe, time-saving and cost-effective method for helping diagnose CAD. The present study was designed to review several articles on the safety, efficacy, and suitability of regadenoson in MPI testing for CAD. Overall, the combined studies demonstrated that use of regadenoson in conjunction with low-level exercise in MPI is a highly efficient and relatively safe test for CAD, especially for more severe health-compromised patients.

  13. How to use MPI communication in highly parallel climate simulations more easily and more efficiently.

    Science.gov (United States)

    Behrens, Jörg; Hanke, Moritz; Jahns, Thomas

    2014-05-01

    In this talk we present a way to facilitate efficient use of MPI communication for developers of climate models. Exploitation of the performance potential of today's highly parallel supercomputers with real world simulations is a complex task. This is partly caused by the low level nature of the MPI communication library which is the dominant communication tool at least for inter-node communication. In order to manage the complexity of the task, climate simulations with non-trivial communication patterns often use an internal abstraction layer above MPI without exploiting the benefits of communication aggregation or MPI-datatypes. The solution for the complexity and performance problem we propose is the communication library YAXT. This library is built on top of MPI and takes high level descriptions of arbitrary domain decompositions and automatically derives an efficient collective data exchange. Several exchanges can be aggregated in order to reduce latency costs. Examples are given which demonstrate the simplicity and the performance gains for selected climate applications.

  14. Proceedings of the first international workshop on multiple partonic interactions at the LHC. MPI'08

    International Nuclear Information System (INIS)

    Bartalini, Paolo; Fano, Livio

    2009-06-01

    The objective of this first workshop on Multiple Partonic Interactions (MPI) at the LHC, that can be regarded as a continuation and extension of the dedicated meetings held at DESY in the years 2006 and 2007, is to raise the profile of MPI studies, summarizing the legacy from the older phenomenology at hadronic colliders and favouring further specific contacts between the theory and experimental communities. The MPI are experiencing a growing popularity and are currently widely invoked to account for observations that would not be explained otherwise: the activity of the Underlying Event, the cross sections for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. At the same time, the implementation of the MPI effects in the Monte Carlo models is quickly proceeding through an increasing level of sophistication and complexity that in perspective achieves deep general implications for the LHC physics. The ultimate ambition of this workshop is to promote the MPI as unification concept between seemingly heterogeneous research lines and to profit of the complete experimental picture in order to constrain their implementation in the models, evaluating the spin offs on the LHC physics program. The workshop is structured in five sections, with the first one dedicated to few selected hot highlights in the High Energy Physics and directly connected to the other ones: Multiple Parton Interactions (in both the soft and the hard regimes), Diffraction, Monte Carlo Generators and Heavy Ions. (orig.)

  15. Exploiting Efficient Transpacking for One-Sided Communication and MPI-IO

    Science.gov (United States)

    Mir, Faisal Ghias; Träff, Jesper Larsson

    Based on a construction of socalled input-output datatypes that define a mapping between non-consecutive input and output buffers, we outline an efficient method for copying of structured data. We term this operation transpacking, and show how transpacking can be applied for the MPI implementation of one-sided communication and MPI-IO. For one-sided communication via shared-memory, we demonstrate the expected performance improvements by up to a factor of two. For individual MPI-IO, the time to read or write from file dominates the overall time, but even here efficient transpacking can in some scenarios reduce file I/O time considerably. The reported results have been achieved on a single NEC SX-8 vector node.

  16. Conflict Detection Algorithm to Minimize Locking for MPI-IO Atomicity

    Science.gov (United States)

    Sehrish, Saba; Wang, Jun; Thakur, Rajeev

    Many scientific applications require high-performance concurrent I/O accesses to a file by multiple processes. Those applications rely indirectly on atomic I/O capabilities in order to perform updates to structured datasets, such as those stored in HDF5 format files. Current support for atomicity in MPI-IO is provided by locking around the operations, imposing lock overhead in all situations, even though in many cases these operations are non-overlapping in the file. We propose to isolate non-overlapping accesses from overlapping ones in independent I/O cases, allowing the non-overlapping ones to proceed without imposing lock overhead. To enable this, we have implemented an efficient conflict detection algorithm in MPI-IO using MPI file views and datatypes. We show that our conflict detection scheme incurs minimal overhead on I/O operations, making it an effective mechanism for avoiding locks when they are not needed.

  17. Performance of MPI parallel processing implemented by MCNP5/ MCNPX for criticality benchmark problems

    International Nuclear Information System (INIS)

    Mark Dennis Usang; Mohd Hairie Rabir; Mohd Amin Sharifuldin Salleh; Mohamad Puad Abu

    2012-01-01

    MPI parallelism are implemented on a SUN Workstation for running MCNPX and on the High Performance Computing Facility (HPC) for running MCNP5. 23 input less obtained from MCNP Criticality Validation Suite are utilized for the purpose of evaluating the amount of speed up achievable by using the parallel capabilities of MPI. More importantly, we will study the economics of using more processors and the type of problem where the performance gain are obvious. This is important to enable better practices of resource sharing especially for the HPC facilities processing time. Future endeavours in this direction might even reveal clues for best MCNP5/ MCNPX coding practices for optimum performance of MPI parallelisms. (author)

  18. Topology-oblivious optimization of MPI broadcast algorithms on extreme-scale platforms

    KAUST Repository

    Hasanov, Khalid

    2015-11-01

    © 2015 Elsevier B.V. All rights reserved. Significant research has been conducted in collective communication operations, in particular in MPI broadcast, on distributed memory platforms. Most of the research efforts aim to optimize the collective operations for particular architectures by taking into account either their topology or platform parameters. In this work we propose a simple but general approach to optimization of the legacy MPI broadcast algorithms, which are widely used in MPICH and Open MPI. The proposed optimization technique is designed to address the challenge of extreme scale of future HPC platforms. It is based on hierarchical transformation of the traditionally flat logical arrangement of communicating processors. Theoretical analysis and experimental results on IBM BlueGene/P and a cluster of the Grid\\'5000 platform are presented.

  19. Relationship between coronary contrast-flow quantitative flow ratio and myocardial ischemia assessed by SPECT MPI

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Jeff M.; Rosendael, Alexander R. van; Jukema, J.W.; Delgado, Victoria; Bax, Jeroen J.; Scholte, Arthur J. [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands); Koning, Gerhard [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Dibbets-Schneider, Petra [Leiden University Medical Center, Department of Nuclear Medicine, Leiden (Netherlands); Mertens, Bart J. [Leiden University Medical Center, Department of Medical Statistics, Leiden (Netherlands); Reiber, Johan H.C. [Medis Medical Imaging Systems B.V., Leiden (Netherlands); Leiden University Medical Center, Department of Radiology, Leiden (Netherlands)

    2017-10-15

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called ''contrast-flow quantitative flow ratio (cQFR)''. Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001). A good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters. (orig.)

  20. Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI.

    Science.gov (United States)

    Smit, Jeff M; Koning, Gerhard; van Rosendael, Alexander R; Dibbets-Schneider, Petra; Mertens, Bart J; Jukema, J Wouter; Delgado, Victoria; Reiber, Johan H C; Bax, Jeroen J; Scholte, Arthur J

    2017-10-01

    A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called "contrast-flow quantitative flow ratio (cQFR)". Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

  1. MSAProbs-MPI: parallel multiple sequence aligner for distributed-memory systems.

    Science.gov (United States)

    González-Domínguez, Jorge; Liu, Yongchao; Touriño, Juan; Schmidt, Bertil

    2016-12-15

    MSAProbs is a state-of-the-art protein multiple sequence alignment tool based on hidden Markov models. It can achieve high alignment accuracy at the expense of relatively long runtimes for large-scale input datasets. In this work we present MSAProbs-MPI, a distributed-memory parallel version of the multithreaded MSAProbs tool that is able to reduce runtimes by exploiting the compute capabilities of common multicore CPU clusters. Our performance evaluation on a cluster with 32 nodes (each containing two Intel Haswell processors) shows reductions in execution time of over one order of magnitude for typical input datasets. Furthermore, MSAProbs-MPI using eight nodes is faster than the GPU-accelerated QuickProbs running on a Tesla K20. Another strong point is that MSAProbs-MPI can deal with large datasets for which MSAProbs and QuickProbs might fail due to time and memory constraints, respectively. Source code in C ++ and MPI running on Linux systems as well as a reference manual are available at http://msaprobs.sourceforge.net CONTACT: jgonzalezd@udc.esSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Lemon : An MPI parallel I/O library for data encapsulation using LIME

    NARCIS (Netherlands)

    Deuzeman, Albert; Reker, Siebren; Urbach, Carsten

    We introduce Lemon, an MPI parallel I/O library that provides efficient parallel I/O of both binary and metadata on massively parallel architectures. Motivated by the demands of the lattice Quantum Chromodynamics community, the data is stored in the SciDAC Lattice QCD Interchange Message

  3. Feasibility of using auto Mod-MPI system, a novel technique for automated measurement of fetal modified myocardial performance index.

    Science.gov (United States)

    Lee, M-Y; Won, H-S; Jeon, E-J; Yoon, H C; Choi, J Y; Hong, S J; Kim, M-J

    2014-06-01

    To evaluate the reproducibility of measurement of the fetal left modified myocardial performance index (Mod-MPI) determined using a novel automated system. This was a prospective study of 116 ultrasound examinations from 110 normal singleton pregnancies at 12 + 1 to 37 + 1 weeks' gestation. Two experienced operators each measured the left Mod-MPI twice manually and twice automatically using the Auto Mod-MPI system. Intra- and interoperator reproducibility were assessed using intraclass correlation coefficients (ICCs) and the manual and automated measurements obtained by the more experienced operator were compared using Bland-Altman plots and ICCs. Both operators successfully measured the left Mod-MPI in all cases using the Auto Mod-MPI system. For both operators, intraoperator reproducibility was higher when performing automated measurements (ICC = 0.967 and 0.962 for Operators 1 and 2, respectively) than when performing manual measurements (ICC = 0.857 and 0.856 for Operators 1 and 2, respectively). Interoperator agreement was also better for automated than for manual measurements (ICC = 0.930 vs 0.723, respectively). There was good agreement between the automated and manual values measured by the more experienced operator. The Auto Mod-MPI system is a reliable technique for measuring fetal left Mod-MPI and demonstrates excellent reproducibility. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

  4. Automatic translation of MPI source into a latency-tolerant, data-driven form

    International Nuclear Information System (INIS)

    Nguyen, Tan; Cicotti, Pietro; Bylaska, Eric; Quinlan, Dan; Baden, Scott

    2017-01-01

    Hiding communication behind useful computation is an important performance programming technique but remains an inscrutable programming exercise even for the expert. We present Bamboo, a code transformation framework that can realize communication overlap in applications written in MPI without the need to intrusively modify the source code. We reformulate MPI source into a task dependency graph representation, which partially orders the tasks, enabling the program to execute in a data-driven fashion under the control of an external runtime system. Experimental results demonstrate that Bamboo significantly reduces communication delays while requiring only modest amounts of programmer annotation for a variety of applications and platforms, including those employing co-processors and accelerators. Moreover, Bamboo’s performance meets or exceeds that of labor-intensive hand coding. As a result, the translator is more than a means of hiding communication costs automatically; it demonstrates the utility of semantic level optimization against a well-known library.

  5. Enabling Highly-Scalable Remote Memory Access Programming with MPI-3 One Sided

    Directory of Open Access Journals (Sweden)

    Robert Gerstenberger

    2014-01-01

    Full Text Available Modern interconnects offer remote direct memory access (RDMA features. Yet, most applications rely on explicit message passing for communications albeit their unwanted overheads. The MPI-3.0 standard defines a programming interface for exploiting RDMA networks directly, however, it's scalability and practicability has to be demonstrated in practice. In this work, we develop scalable bufferless protocols that implement the MPI-3.0 specification. Our protocols support scaling to millions of cores with negligible memory consumption while providing highest performance and minimal overheads. To arm programmers, we provide a spectrum of performance models for all critical functions and demonstrate the usability of our library and models with several application studies with up to half a million processes. We show that our design is comparable to, or better than UPC and Fortran Coarrays in terms of latency, bandwidth and message rate. We also demonstrate application performance improvements with comparable programming complexity.

  6. Study on MPI/OpenMP hybrid parallelism for Monte Carlo neutron transport code

    International Nuclear Information System (INIS)

    Liang Jingang; Xu Qi; Wang Kan; Liu Shiwen

    2013-01-01

    Parallel programming with mixed mode of messages-passing and shared-memory has several advantages when used in Monte Carlo neutron transport code, such as fitting hardware of distributed-shared clusters, economizing memory demand of Monte Carlo transport, improving parallel performance, and so on. MPI/OpenMP hybrid parallelism was implemented based on a one dimension Monte Carlo neutron transport code. Some critical factors affecting the parallel performance were analyzed and solutions were proposed for several problems such as contention access, lock contention and false sharing. After optimization the code was tested finally. It is shown that the hybrid parallel code can reach good performance just as pure MPI parallel program, while it saves a lot of memory usage at the same time. Therefore hybrid parallel is efficient for achieving large-scale parallel of Monte Carlo neutron transport. (authors)

  7. Machine-learning model observer for detection and localization tasks in clinical SPECT-MPI

    Science.gov (United States)

    Parages, Felipe M.; O'Connor, J. Michael; Pretorius, P. Hendrik; Brankov, Jovan G.

    2016-03-01

    In this work we propose a machine-learning MO based on Naive-Bayes classification (NB-MO) for the diagnostic tasks of detection, localization and assessment of perfusion defects in clinical SPECT Myocardial Perfusion Imaging (MPI), with the goal of evaluating several image reconstruction methods used in clinical practice. NB-MO uses image features extracted from polar-maps in order to predict lesion detection, localization and severity scores given by human readers in a series of 3D SPECT-MPI. The population used to tune (i.e. train) the NB-MO consisted of simulated SPECT-MPI cases - divided into normals or with lesions in variable sizes and locations - reconstructed using filtered backprojection (FBP) method. An ensemble of five human specialists (physicians) read a subset of simulated reconstructed images, and assigned a perfusion score for each region of the left-ventricle (LV). Polar-maps generated from the simulated volumes along with their corresponding human scores were used to train five NB-MOs (one per human reader), which are subsequently applied (i.e. tested) on three sets of clinical SPECT-MPI polar maps, in order to predict human detection and localization scores. The clinical "testing" population comprises healthy individuals and patients suffering from coronary artery disease (CAD) in three possible regions, namely: LAD, LcX and RCA. Each clinical case was reconstructed using three reconstruction strategies, namely: FBP with no SC (i.e. scatter compensation), OSEM with Triple Energy Window (TEW) SC method, and OSEM with Effective Source Scatter Estimation (ESSE) SC. Alternative Free-Response (AFROC) analysis of perfusion scores shows that NB-MO predicts a higher human performance for scatter-compensated reconstructions, in agreement with what has been reported in published literature. These results suggest that NB-MO has good potential to generalize well to reconstruction methods not used during training, even for reasonably dissimilar datasets (i

  8. Parallel Computing Characteristics of CUPID code under MPI and Hybrid environment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Ryong; Yoon, Han Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jeon, Byoung Jin; Choi, Hyoung Gwon [Seoul National Univ. of Science and Technology, Seoul (Korea, Republic of)

    2014-05-15

    In this paper, a characteristic of parallel algorithm is presented for solving an elliptic type equation of CUPID via domain decomposition method using the MPI and the parallel performance is estimated in terms of a scalability which shows the speedup ratio. In addition, the time-consuming pattern of major subroutines is studied. Two different grid systems are taken into account: 40,000 meshes for coarse system and 320,000 meshes for fine system. Since the matrix of the CUPID code differs according to whether the flow is single-phase or two-phase, the effect of matrix shape is evaluated. Finally, the effect of the preconditioner for matrix solver is also investigated. Finally, the hybrid (OpenMP+MPI) parallel algorithm is introduced and discussed in detail for solving pressure solver. Component-scale thermal-hydraulics code, CUPID has been developed for two-phase flow analysis, which adopts a three-dimensional, transient, three-field model, and parallelized to fulfill a recent demand for long-transient and highly resolved multi-phase flow behavior. In this study, the parallel performance of the CUPID code was investigated in terms of scalability. The CUPID code was parallelized with domain decomposition method. The MPI library was adopted to communicate the information at the neighboring domain. For managing the sparse matrix effectively, the CSR storage format is used. To take into account the characteristics of the pressure matrix which turns to be asymmetric for two-phase flow, both single-phase and two-phase calculations were run. In addition, the effect of the matrix size and preconditioning was also investigated. The fine mesh calculation shows better scalability than the coarse mesh because the number of coarse mesh does not need to decompose the computational domain excessively. The fine mesh can be present good scalability when dividing geometry with considering the ratio between computation and communication time. For a given mesh, single-phase flow

  9. Fortran code for SU(3) lattice gauge theory with and without MPI checkerboard parallelization

    Science.gov (United States)

    Berg, Bernd A.; Wu, Hao

    2012-10-01

    We document plain Fortran and Fortran MPI checkerboard code for Markov chain Monte Carlo simulations of pure SU(3) lattice gauge theory with the Wilson action in D dimensions. The Fortran code uses periodic boundary conditions and is suitable for pedagogical purposes and small scale simulations. For the Fortran MPI code two geometries are covered: the usual torus with periodic boundary conditions and the double-layered torus as defined in the paper. Parallel computing is performed on checkerboards of sublattices, which partition the full lattice in one, two, and so on, up to D directions (depending on the parameters set). For updating, the Cabibbo-Marinari heatbath algorithm is used. We present validations and test runs of the code. Performance is reported for a number of currently used Fortran compilers and, when applicable, MPI versions. For the parallelized code, performance is studied as a function of the number of processors. Program summary Program title: STMC2LSU3MPI Catalogue identifier: AEMJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 26666 No. of bytes in distributed program, including test data, etc.: 233126 Distribution format: tar.gz Programming language: Fortran 77 compatible with the use of Fortran 90/95 compilers, in part with MPI extensions. Computer: Any capable of compiling and executing Fortran 77 or Fortran 90/95, when needed with MPI extensions. Operating system: Red Hat Enterprise Linux Server 6.1 with OpenMPI + pgf77 11.8-0, Centos 5.3 with OpenMPI + gfortran 4.1.2, Cray XT4 with MPICH2 + pgf90 11.2-0. Has the code been vectorised or parallelized?: Yes, parallelized using MPI extensions. Number of processors used: 2 to 11664 RAM: 200 Mega bytes per process. Classification: 11

  10. Solution of finite element problems using hybrid parallelization with MPI and OpenMP Solution of finite element problems using hybrid parallelization with MPI and OpenMP

    Directory of Open Access Journals (Sweden)

    José Miguel Vargas-Félix

    2012-11-01

    Full Text Available The Finite Element Method (FEM is used to solve problems like solid deformation and heat diffusion in domains with complex geometries. This kind of geometries requires discretization with millions of elements; this is equivalent to solve systems of equations with sparse matrices and tens or hundreds of millions of variables. The aim is to use computer clusters to solve these systems. The solution method used is Schur substructuration. Using it is possible to divide a large system of equations into many small ones to solve them more efficiently. This method allows parallelization. MPI (Message Passing Interface is used to distribute the systems of equations to solve each one in a computer of a cluster. Each system of equations is solved using a solver implemented to use OpenMP as a local parallelization method.The Finite Element Method (FEM is used to solve problems like solid deformation and heat diffusion in domains with complex geometries. This kind of geometries requires discretization with millions of elements; this is equivalent to solve systems of equations with sparse matrices and tens or hundreds of millions of variables. The aim is to use computer clusters to solve these systems. The solution method used is Schur substructuration. Using it is possible to divide a large system of equations into many small ones to solve them more efficiently. This method allows parallelization. MPI (Message Passing Interface is used to distribute the systems of equations to solve each one in a computer of a cluster. Each system of equations is solved using a solver implemented to use OpenMP as a local parallelization method.

  11. CORBA and MPI-based 'backbone' for coupling advanced simulation tools

    International Nuclear Information System (INIS)

    Seydaliev, M.; Caswell, D.

    2014-01-01

    There is a growing international interest in using coupled, multidisciplinary computer simulations for a variety of purposes, including nuclear reactor safety analysis. Reactor behaviour can be modeled using a suite of computer programs simulating phenomena or predicting parameters that can be categorized into disciplines such as Thermalhydraulics, Neutronics, Fuel, Fuel Channels, Fission Product Release and Transport, Containment and Atmospheric Dispersion, and Severe Accident Analysis. Traditionally, simulations used for safety analysis individually addressed only the behaviour within a single discipline, based upon static input data from other simulation programs. The limitation of using a suite of stand-alone simulations is that phenomenological interdependencies or temporal feedback between the parameters calculated within individual simulations cannot be adequately captured. To remove this shortcoming, multiple computer simulations for different disciplines must exchange data during runtime to address these interdependencies. This article describes the concept of a new framework, which we refer to as the 'Backbone', to provide the necessary runtime exchange of data. The Backbone, currently under development at AECL for a preliminary feasibility study, is a hybrid design using features taken from the Common Object Request Broker Architecture (CORBA), a standard defined by the Object Management Group, and the Message Passing Interface (MPI), a standard developed by a group of researchers from academia and industry. Both have well-tested and efficient implementations, including some that are freely available under the GNU public licenses. The CORBA component enables individual programs written in different languages and running on different platforms within a network to exchange data with each other, thus behaving like a single application. MPI provides the process-to-process intercommunication between these programs. This paper outlines the different CORBA and

  12. Performance Modeling of Hybrid MPI/OpenMP Scientific Applications on Large-scale Multicore Cluster Systems

    KAUST Repository

    Wu, Xingfu

    2011-08-01

    In this paper, we present a performance modeling framework based on memory bandwidth contention time and a parameterized communication model to predict the performance of OpenMP, MPI and hybrid applications with weak scaling on three large-scale multicore clusters: IBM POWER4, POWER5+ and Blue Gene/P, and analyze the performance of these MPI, OpenMP and hybrid applications. We use STREAM memory benchmarks to provide initial performance analysis and model validation of MPI and OpenMP applications on these multicore clusters because the measured sustained memory bandwidth can provide insight into the memory bandwidth that a system should sustain on scientific applications with the same amount of workload per core. In addition to using these benchmarks, we also use a weak-scaling hybrid MPI/OpenMP large-scale scientific application: Gyro kinetic Toroidal Code in magnetic fusion to validate our performance model of the hybrid application on these multicore clusters. The validation results for our performance modeling method show less than 7.77% error rate in predicting the performance of hybrid MPI/OpenMP GTC on up to 512 cores on these multicore clusters. © 2011 IEEE.

  13. Proceedings of the first international workshop on multiple partonic interactions at the LHC. MPI'08

    Energy Technology Data Exchange (ETDEWEB)

    Bartalini, Paolo [National Taiwan Univ., Taipei (China); Fano, Livio (eds.) [Istituto Nazionale di Fisica Nucleare, Perugia (Italy)

    2009-06-15

    The objective of this first workshop on Multiple Partonic Interactions (MPI) at the LHC, that can be regarded as a continuation and extension of the dedicated meetings held at DESY in the years 2006 and 2007, is to raise the profile of MPI studies, summarizing the legacy from the older phenomenology at hadronic colliders and favouring further specific contacts between the theory and experimental communities. The MPI are experiencing a growing popularity and are currently widely invoked to account for observations that would not be explained otherwise: the activity of the Underlying Event, the cross sections for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. At the same time, the implementation of the MPI effects in the Monte Carlo models is quickly proceeding through an increasing level of sophistication and complexity that in perspective achieves deep general implications for the LHC physics. The ultimate ambition of this workshop is to promote the MPI as unification concept between seemingly heterogeneous research lines and to profit of the complete experimental picture in order to constrain their implementation in the models, evaluating the spin offs on the LHC physics program. The workshop is structured in five sections, with the first one dedicated to few selected hot highlights in the High Energy Physics and directly connected to the other ones: Multiple Parton Interactions (in both the soft and the hard regimes), Diffraction, Monte Carlo Generators and Heavy Ions. (orig.)

  14. Performance Modeling of Hybrid MPI/OpenMP Scientific Applications on Large-scale Multicore Cluster Systems

    KAUST Repository

    Wu, Xingfu; Taylor, Valerie

    2011-01-01

    In this paper, we present a performance modeling framework based on memory bandwidth contention time and a parameterized communication model to predict the performance of OpenMP, MPI and hybrid applications with weak scaling on three large-scale multicore clusters: IBM POWER4, POWER5+ and Blue Gene/P, and analyze the performance of these MPI, OpenMP and hybrid applications. We use STREAM memory benchmarks to provide initial performance analysis and model validation of MPI and OpenMP applications on these multicore clusters because the measured sustained memory bandwidth can provide insight into the memory bandwidth that a system should sustain on scientific applications with the same amount of workload per core. In addition to using these benchmarks, we also use a weak-scaling hybrid MPI/OpenMP large-scale scientific application: Gyro kinetic Toroidal Code in magnetic fusion to validate our performance model of the hybrid application on these multicore clusters. The validation results for our performance modeling method show less than 7.77% error rate in predicting the performance of hybrid MPI/OpenMP GTC on up to 512 cores on these multicore clusters. © 2011 IEEE.

  15. Aminophylline and caffeine for reversal of adverse symptoms associated with regadenoson SPECT MPI.

    Science.gov (United States)

    Doran, Jesse A; Sajjad, Waseem; Schneider, Marabel D; Gupta, Rohit; Mackin, Maria L; Schwartz, Ronald G

    2017-06-01

    Aminophylline shortages led us to compare intravenous (IV) aminophylline with IV and oral (PO) caffeine during routine pharmacologic stress testing with SPECT MPI. We measured presence, duration, and reversal of adverse symptoms and cardiac events following regadenoson administration in consecutive patients randomized to IV aminophylline (100 mg administered over 30-60 seconds), IV caffeine citrate (60 mg infused over 3-5 minutes), or PO caffeine as coffee or diet cola. Of 241 patients, 152 (63%) received regadenoson reversal intervention. Complete (CR), predominant (PRE), or partial (PR) reversal was observed in 99%. CR by IV aminophylline (87%), IV caffeine (87%), and PO caffeine (78%) were similar (P = NS). Time to CR (162 ± 12.6 seconds, mean ± SD) was similar in treatment arms. PO caffeine was inferior to IV aminophylline for CR + PRE. IV aminophylline and IV caffeine provide rapid, safe reversal of regadenoson-induced adverse effects during SPECT MPI. Oral caffeine appeared similarly effective for CR but not for the combined CR + PRE. Our results suggest PO caffeine may be an effective initial strategy for reversal of regadenoson, but IV aminophylline or IV caffeine should be available to optimize symptom reversal as needed.

  16. Optimization approaches to mpi and area merging-based parallel buffer algorithm

    Directory of Open Access Journals (Sweden)

    Junfu Fan

    Full Text Available On buffer zone construction, the rasterization-based dilation method inevitably introduces errors, and the double-sided parallel line method involves a series of complex operations. In this paper, we proposed a parallel buffer algorithm based on area merging and MPI (Message Passing Interface to improve the performances of buffer analyses on processing large datasets. Experimental results reveal that there are three major performance bottlenecks which significantly impact the serial and parallel buffer construction efficiencies, including the area merging strategy, the task load balance method and the MPI inter-process results merging strategy. Corresponding optimization approaches involving tree-like area merging strategy, the vertex number oriented parallel task partition method and the inter-process results merging strategy were suggested to overcome these bottlenecks. Experiments were carried out to examine the performance efficiency of the optimized parallel algorithm. The estimation results suggested that the optimization approaches could provide high performance and processing ability for buffer construction in a cluster parallel environment. Our method could provide insights into the parallelization of spatial analysis algorithm.

  17. SeMPI: a genome-based secondary metabolite prediction and identification web server.

    Science.gov (United States)

    Zierep, Paul F; Padilla, Natàlia; Yonchev, Dimitar G; Telukunta, Kiran K; Klementz, Dennis; Günther, Stefan

    2017-07-03

    The secondary metabolism of bacteria, fungi and plants yields a vast number of bioactive substances. The constantly increasing amount of published genomic data provides the opportunity for an efficient identification of gene clusters by genome mining. Conversely, for many natural products with resolved structures, the encoding gene clusters have not been identified yet. Even though genome mining tools have become significantly more efficient in the identification of biosynthetic gene clusters, structural elucidation of the actual secondary metabolite is still challenging, especially due to as yet unpredictable post-modifications. Here, we introduce SeMPI, a web server providing a prediction and identification pipeline for natural products synthesized by polyketide synthases of type I modular. In order to limit the possible structures of PKS products and to include putative tailoring reactions, a structural comparison with annotated natural products was introduced. Furthermore, a benchmark was designed based on 40 gene clusters with annotated PKS products. The web server of the pipeline (SeMPI) is freely available at: http://www.pharmaceutical-bioinformatics.de/sempi. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  18. Pthreads vs MPI Parallel Performance of Angular-Domain Decomposed S

    International Nuclear Information System (INIS)

    Azmy, Y.Y.; Barnett, D.A.

    2000-01-01

    Two programming models for parallelizing the Angular Domain Decomposition (ADD) of the discrete ordinates (S n ) approximation of the neutron transport equation are examined. These are the shared memory model based on the POSIX threads (Pthreads) standard, and the message passing model based on the Message Passing Interface (MPI) standard. These standard libraries are available on most multiprocessor platforms thus making the resulting parallel codes widely portable. The question is: on a fixed platform, and for a particular code solving a given test problem, which of the two programming models delivers better parallel performance? Such comparison is possible on Symmetric Multi-Processors (SMP) architectures in which several CPUs physically share a common memory, and in addition are capable of emulating message passing functionality. Implementation of the two-dimensional,(S n ), Arbitrarily High Order Transport (AHOT) code for solving neutron transport problems using these two parallelization models is described. Measured parallel performance of each model on the COMPAQ AlphaServer 8400 and the SGI Origin 2000 platforms is described, and comparison of the observed speedup for the two programming models is reported. For the case presented in this paper it appears that the MPI implementation scales better than the Pthreads implementation on both platforms

  19. Performance Comparison of OpenMP, MPI, and MapReduce in Practical Problems

    Directory of Open Access Journals (Sweden)

    Sol Ji Kang

    2015-01-01

    Full Text Available With problem size and complexity increasing, several parallel and distributed programming models and frameworks have been developed to efficiently handle such problems. This paper briefly reviews the parallel computing models and describes three widely recognized parallel programming frameworks: OpenMP, MPI, and MapReduce. OpenMP is the de facto standard for parallel programming on shared memory systems. MPI is the de facto industry standard for distributed memory systems. MapReduce framework has become the de facto standard for large scale data-intensive applications. Qualitative pros and cons of each framework are known, but quantitative performance indexes help get a good picture of which framework to use for the applications. As benchmark problems to compare those frameworks, two problems are chosen: all-pairs-shortest-path problem and data join problem. This paper presents the parallel programs for the problems implemented on the three frameworks, respectively. It shows the experiment results on a cluster of computers. It also discusses which is the right tool for the jobs by analyzing the characteristics and performance of the paradigms.

  20. Automatic Transformation of MPI Programs to Asynchronous, Graph-Driven Form

    Energy Technology Data Exchange (ETDEWEB)

    Baden, Scott B [University of California, San Diego; Weare, John H [University of California, San Diego; Bylaska, Eric J [Pacific Northwest National Laboratory

    2013-04-30

    The goals of this project are to develop new, scalable, high-fidelity algorithms for atomic-level simulations and program transformations that automatically restructure existing applications, enabling them to scale forward to Petascale systems and beyond. The techniques enable legacy MPI application code to exploit greater parallelism though increased latency hiding and improved workload assignment. The techniques were successfully demonstrated on high-end scalable systems located at DOE laboratories. Besides the automatic MPI program transformations efforts, the project also developed several new scalable algorithms for ab-initio molecular dynamics, including new massively parallel algorithms for hybrid DFT and new parallel in time algorithms for molecular dynamics and ab-initio molecular dynamics. These algorithms were shown to scale to very large number of cores, and they were designed to work in the latency hiding framework developed in this project. The effectiveness of the developments was enhanced by the direct application to real grand challenge simulation problems covering a wide range of technologically important applications, time scales and accuracies. These included the simulation of the electronic structure of mineral/fluid interfaces, the very accurate simulation of chemical reactions in microsolvated environments, and the simulation of chemical behavior in very large enzyme reactions.

  1. Development of a parallel genetic algorithm using MPI and its application in a nuclear reactor core. Design optimization

    International Nuclear Information System (INIS)

    Waintraub, Marcel; Pereira, Claudio M.N.A.; Baptista, Rafael P.

    2005-01-01

    This work presents the development of a distributed parallel genetic algorithm applied to a nuclear reactor core design optimization. In the implementation of the parallelism, a 'Message Passing Interface' (MPI) library, standard for parallel computation in distributed memory platforms, has been used. Another important characteristic of MPI is its portability for various architectures. The main objectives of this paper are: validation of the results obtained by the application of this algorithm in a nuclear reactor core optimization problem, through comparisons with previous results presented by Pereira et al.; and performance test of the Brazilian Nuclear Engineering Institute (IEN) cluster in reactors physics optimization problems. The experiments demonstrated that the developed parallel genetic algorithm using the MPI library presented significant gains in the obtained results and an accentuated reduction of the processing time. Such results ratify the use of the parallel genetic algorithms for the solution of nuclear reactor core optimization problems. (author)

  2. Hybrid MPI/OpenMP parallelization of the explicit Volterra integral equation solver for multi-core computer architectures

    KAUST Repository

    Al Jarro, Ahmed

    2011-08-01

    A hybrid MPI/OpenMP scheme for efficiently parallelizing the explicit marching-on-in-time (MOT)-based solution of the time-domain volume (Volterra) integral equation (TD-VIE) is presented. The proposed scheme equally distributes tested field values and operations pertinent to the computation of tested fields among the nodes using the MPI standard; while the source field values are stored in all nodes. Within each node, OpenMP standard is used to further accelerate the computation of the tested fields. Numerical results demonstrate that the proposed parallelization scheme scales well for problems involving three million or more spatial discretization elements. © 2011 IEEE.

  3. IB: A Monte Carlo simulation tool for neutron scattering instrument design under PVM and MPI

    International Nuclear Information System (INIS)

    Zhao Jinkui

    2011-01-01

    Design of modern neutron scattering instruments relies heavily on Monte Carlo simulation tools for optimization. IB is one such tool written in C++ and implemented under Parallel Virtual Machine and the Message Passing Interface. The program was initially written for the design and optimization of the EQ-SANS instrument at the Spallation Neutron Source. One of its features is the ability to group simple instrument components into more complex ones at the user input level, e.g. grouping neutron mirrors into neutron guides and curved benders. The simulation engine manages the grouped components such that neutrons entering a group are properly operated upon by all components, multiple times if needed, before exiting the group. Thus, only a few basic optical modules are needed at the programming level. For simulations that require higher computer speeds, the program can be compiled and run in parallel modes using either the PVM or the MPI architectures.

  4. Warm Paleocene/Eocene climate as simulated in ECHAM5/MPI-OM

    Directory of Open Access Journals (Sweden)

    M. Heinemann

    2009-12-01

    Full Text Available We investigate the late Paleocene/early Eocene (PE climate using the coupled atmosphere-ocean-sea ice model ECHAM5/MPI-OM. The surface in our PE control simulation is on average 297 K warm and ice-free, despite a moderate atmospheric CO2 concentration of 560 ppm. Compared to a pre-industrial reference simulation (PR, low latitudes are 5 to 8 K warmer, while high latitudes are up to 40 K warmer. This high-latitude amplification is in line with proxy data, yet a comparison to sea surface temperature proxy data suggests that the Arctic surface temperatures are still too low in our PE simulation.

    To identify the mechanisms that cause the PE-PR surface temperature differences, we fit two simple energy balance models to the ECHAM5/MPI-OM results. We find that about 2/3 of the PE-PR global mean surface temperature difference are caused by a smaller clear sky emissivity due to higher atmospheric CO2 and water vapour concentrations in PE compared to PR; 1/3 is due to a smaller planetary albedo. The reduction of the pole-to-equator temperature gradient in PE compared to PR is due to (1 the large high-latitude effect of the higher CO2 and water vapour concentrations in PE compared to PR, (2 the lower Antarctic orography, (3 the smaller surface albedo at high latitudes, and (4 longwave cloud radiative effects. Our results support the hypothesis that local radiative effects rather than increased meridional heat transports were responsible for the "equable" PE climate.

  5. The MPI facial expression database--a validated database of emotional and conversational facial expressions.

    Directory of Open Access Journals (Sweden)

    Kathrin Kaulard

    Full Text Available The ability to communicate is one of the core aspects of human life. For this, we use not only verbal but also nonverbal signals of remarkable complexity. Among the latter, facial expressions belong to the most important information channels. Despite the large variety of facial expressions we use in daily life, research on facial expressions has so far mostly focused on the emotional aspect. Consequently, most databases of facial expressions available to the research community also include only emotional expressions, neglecting the largely unexplored aspect of conversational expressions. To fill this gap, we present the MPI facial expression database, which contains a large variety of natural emotional and conversational expressions. The database contains 55 different facial expressions performed by 19 German participants. Expressions were elicited with the help of a method-acting protocol, which guarantees both well-defined and natural facial expressions. The method-acting protocol was based on every-day scenarios, which are used to define the necessary context information for each expression. All facial expressions are available in three repetitions, in two intensities, as well as from three different camera angles. A detailed frame annotation is provided, from which a dynamic and a static version of the database have been created. In addition to describing the database in detail, we also present the results of an experiment with two conditions that serve to validate the context scenarios as well as the naturalness and recognizability of the video sequences. Our results provide clear evidence that conversational expressions can be recognized surprisingly well from visual information alone. The MPI facial expression database will enable researchers from different research fields (including the perceptual and cognitive sciences, but also affective computing, as well as computer vision to investigate the processing of a wider range of natural

  6. The MPI Facial Expression Database — A Validated Database of Emotional and Conversational Facial Expressions

    Science.gov (United States)

    Kaulard, Kathrin; Cunningham, Douglas W.; Bülthoff, Heinrich H.; Wallraven, Christian

    2012-01-01

    The ability to communicate is one of the core aspects of human life. For this, we use not only verbal but also nonverbal signals of remarkable complexity. Among the latter, facial expressions belong to the most important information channels. Despite the large variety of facial expressions we use in daily life, research on facial expressions has so far mostly focused on the emotional aspect. Consequently, most databases of facial expressions available to the research community also include only emotional expressions, neglecting the largely unexplored aspect of conversational expressions. To fill this gap, we present the MPI facial expression database, which contains a large variety of natural emotional and conversational expressions. The database contains 55 different facial expressions performed by 19 German participants. Expressions were elicited with the help of a method-acting protocol, which guarantees both well-defined and natural facial expressions. The method-acting protocol was based on every-day scenarios, which are used to define the necessary context information for each expression. All facial expressions are available in three repetitions, in two intensities, as well as from three different camera angles. A detailed frame annotation is provided, from which a dynamic and a static version of the database have been created. In addition to describing the database in detail, we also present the results of an experiment with two conditions that serve to validate the context scenarios as well as the naturalness and recognizability of the video sequences. Our results provide clear evidence that conversational expressions can be recognized surprisingly well from visual information alone. The MPI facial expression database will enable researchers from different research fields (including the perceptual and cognitive sciences, but also affective computing, as well as computer vision) to investigate the processing of a wider range of natural facial expressions

  7. Hybrid MPI/OpenMP parallelization of the explicit Volterra integral equation solver for multi-core computer architectures

    KAUST Repository

    Al Jarro, Ahmed; Bagci, Hakan

    2011-01-01

    A hybrid MPI/OpenMP scheme for efficiently parallelizing the explicit marching-on-in-time (MOT)-based solution of the time-domain volume (Volterra) integral equation (TD-VIE) is presented. The proposed scheme equally distributes tested field values

  8. High-order finite-element seismic wave propagation modeling with MPI on a large GPU cluster

    International Nuclear Information System (INIS)

    Komatitsch, Dimitri; Erlebacher, Gordon; Goeddeke, Dominik; Michea, David

    2010-01-01

    We implement a high-order finite-element application, which performs the numerical simulation of seismic wave propagation resulting for instance from earthquakes at the scale of a continent or from active seismic acquisition experiments in the oil industry, on a large cluster of NVIDIA Tesla graphics cards using the CUDA programming environment and non-blocking message passing based on MPI. Contrary to many finite-element implementations, ours is implemented successfully in single precision, maximizing the performance of current generation GPUs. We discuss the implementation and optimization of the code and compare it to an existing very optimized implementation in C language and MPI on a classical cluster of CPU nodes. We use mesh coloring to efficiently handle summation operations over degrees of freedom on an unstructured mesh, and non-blocking MPI messages in order to overlap the communications across the network and the data transfer to and from the device via PCIe with calculations on the GPU. We perform a number of numerical tests to validate the single-precision CUDA and MPI implementation and assess its accuracy. We then analyze performance measurements and depending on how the problem is mapped to the reference CPU cluster, we obtain a speedup of 20x or 12x.

  9. Experiences Using Hybrid MPI/OpenMP in the Real World: Parallelization of a 3D CFD Solver for Multi-Core Node Clusters

    Directory of Open Access Journals (Sweden)

    Gabriele Jost

    2010-01-01

    Full Text Available Today most systems in high-performance computing (HPC feature a hierarchical hardware design: shared-memory nodes with several multi-core CPUs are connected via a network infrastructure. When parallelizing an application for these architectures it seems natural to employ a hierarchical programming model such as combining MPI and OpenMP. Nevertheless, there is the general lore that pure MPI outperforms the hybrid MPI/OpenMP approach. In this paper, we describe the hybrid MPI/OpenMP parallelization of IR3D (Incompressible Realistic 3-D code, a full-scale real-world application, which simulates the environmental effects on the evolution of vortices trailing behind control surfaces of underwater vehicles. We discuss performance, scalability and limitations of the pure MPI version of the code on a variety of hardware platforms and show how the hybrid approach can help to overcome certain limitations.

  10. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Directory of Open Access Journals (Sweden)

    Johannes Salamon

    Full Text Available In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI / magnetic resonance imaging (MRI road map approach and an MPI-guided approach using a blood pool tracer.A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4 was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography.Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide.4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  11. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Science.gov (United States)

    Salamon, Johannes; Hofmann, Martin; Jung, Caroline; Kaul, Michael Gerhard; Werner, Franziska; Them, Kolja; Reimer, Rudolph; Nielsen, Peter; Vom Scheidt, Annika; Adam, Gerhard; Knopp, Tobias; Ittrich, Harald

    2016-01-01

    In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI) / magnetic resonance imaging (MRI) road map approach and an MPI-guided approach using a blood pool tracer. A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4) was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography. Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide. 4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  12. Performance characteristics of hybrid MPI/OpenMP implementations of NAS parallel benchmarks SP and BT on large-scale multicore supercomputers

    KAUST Repository

    Wu, Xingfu; Taylor, Valerie

    2011-01-01

    The NAS Parallel Benchmarks (NPB) are well-known applications with the fixed algorithms for evaluating parallel systems and tools. Multicore supercomputers provide a natural programming paradigm for hybrid programs, whereby OpenMP can be used with the data sharing with the multicores that comprise a node and MPI can be used with the communication between nodes. In this paper, we use SP and BT benchmarks of MPI NPB 3.3 as a basis for a comparative approach to implement hybrid MPI/OpenMP versions of SP and BT. In particular, we can compare the performance of the hybrid SP and BT with the MPI counterparts on large-scale multicore supercomputers. Our performance results indicate that the hybrid SP outperforms the MPI SP by up to 20.76%, and the hybrid BT outperforms the MPI BT by up to 8.58% on up to 10,000 cores on BlueGene/P at Argonne National Laboratory and Jaguar (Cray XT4/5) at Oak Ridge National Laboratory. We also use performance tools and MPI trace libraries available on these supercomputers to further investigate the performance characteristics of the hybrid SP and BT.

  13. Performance Characteristics of Hybrid MPI/OpenMP Implementations of NAS Parallel Benchmarks SP and BT on Large-Scale Multicore Clusters

    KAUST Repository

    Wu, X.; Taylor, V.

    2011-01-01

    The NAS Parallel Benchmarks (NPB) are well-known applications with fixed algorithms for evaluating parallel systems and tools. Multicore clusters provide a natural programming paradigm for hybrid programs, whereby OpenMP can be used with the data sharing with the multicores that comprise a node, and MPI can be used with the communication between nodes. In this paper, we use Scalar Pentadiagonal (SP) and Block Tridiagonal (BT) benchmarks of MPI NPB 3.3 as a basis for a comparative approach to implement hybrid MPI/OpenMP versions of SP and BT. In particular, we can compare the performance of the hybrid SP and BT with the MPI counterparts on large-scale multicore clusters, Intrepid (BlueGene/P) at Argonne National Laboratory and Jaguar (Cray XT4/5) at Oak Ridge National Laboratory. Our performance results indicate that the hybrid SP outperforms the MPI SP by up to 20.76 %, and the hybrid BT outperforms the MPI BT by up to 8.58 % on up to 10 000 cores on Intrepid and Jaguar. We also use performance tools and MPI trace libraries available on these clusters to further investigate the performance characteristics of the hybrid SP and BT. © 2011 The Author. Published by Oxford University Press on behalf of The British Computer Society. All rights reserved.

  14. Performance characteristics of hybrid MPI/OpenMP implementations of NAS parallel benchmarks SP and BT on large-scale multicore supercomputers

    KAUST Repository

    Wu, Xingfu

    2011-03-29

    The NAS Parallel Benchmarks (NPB) are well-known applications with the fixed algorithms for evaluating parallel systems and tools. Multicore supercomputers provide a natural programming paradigm for hybrid programs, whereby OpenMP can be used with the data sharing with the multicores that comprise a node and MPI can be used with the communication between nodes. In this paper, we use SP and BT benchmarks of MPI NPB 3.3 as a basis for a comparative approach to implement hybrid MPI/OpenMP versions of SP and BT. In particular, we can compare the performance of the hybrid SP and BT with the MPI counterparts on large-scale multicore supercomputers. Our performance results indicate that the hybrid SP outperforms the MPI SP by up to 20.76%, and the hybrid BT outperforms the MPI BT by up to 8.58% on up to 10,000 cores on BlueGene/P at Argonne National Laboratory and Jaguar (Cray XT4/5) at Oak Ridge National Laboratory. We also use performance tools and MPI trace libraries available on these supercomputers to further investigate the performance characteristics of the hybrid SP and BT.

  15. Performance Characteristics of Hybrid MPI/OpenMP Implementations of NAS Parallel Benchmarks SP and BT on Large-Scale Multicore Clusters

    KAUST Repository

    Wu, X.

    2011-07-18

    The NAS Parallel Benchmarks (NPB) are well-known applications with fixed algorithms for evaluating parallel systems and tools. Multicore clusters provide a natural programming paradigm for hybrid programs, whereby OpenMP can be used with the data sharing with the multicores that comprise a node, and MPI can be used with the communication between nodes. In this paper, we use Scalar Pentadiagonal (SP) and Block Tridiagonal (BT) benchmarks of MPI NPB 3.3 as a basis for a comparative approach to implement hybrid MPI/OpenMP versions of SP and BT. In particular, we can compare the performance of the hybrid SP and BT with the MPI counterparts on large-scale multicore clusters, Intrepid (BlueGene/P) at Argonne National Laboratory and Jaguar (Cray XT4/5) at Oak Ridge National Laboratory. Our performance results indicate that the hybrid SP outperforms the MPI SP by up to 20.76 %, and the hybrid BT outperforms the MPI BT by up to 8.58 % on up to 10 000 cores on Intrepid and Jaguar. We also use performance tools and MPI trace libraries available on these clusters to further investigate the performance characteristics of the hybrid SP and BT. © 2011 The Author. Published by Oxford University Press on behalf of The British Computer Society. All rights reserved.

  16. Large Scale Frequent Pattern Mining using MPI One-Sided Model

    Energy Technology Data Exchange (ETDEWEB)

    Vishnu, Abhinav; Agarwal, Khushbu

    2015-09-08

    In this paper, we propose a work-stealing runtime --- Library for Work Stealing LibWS --- using MPI one-sided model for designing scalable FP-Growth --- {\\em de facto} frequent pattern mining algorithm --- on large scale systems. LibWS provides locality efficient and highly scalable work-stealing techniques for load balancing on a variety of data distributions. We also propose a novel communication algorithm for FP-growth data exchange phase, which reduces the communication complexity from state-of-the-art O(p) to O(f + p/f) for p processes and f frequent attributed-ids. FP-Growth is implemented using LibWS and evaluated on several work distributions and support counts. An experimental evaluation of the FP-Growth on LibWS using 4096 processes on an InfiniBand Cluster demonstrates excellent efficiency for several work distributions (87\\% efficiency for Power-law and 91% for Poisson). The proposed distributed FP-Tree merging algorithm provides 38x communication speedup on 4096 cores.

  17. Experiences in the parallelization of the discrete ordinates method using OpenMP and MPI

    Energy Technology Data Exchange (ETDEWEB)

    Pautz, A. [TUV Hannover/Sachsen-Anhalt e.V. (Germany); Langenbuch, S. [Gesellschaft fur Anlagen- und Reaktorsicherheit (GRS) mbH (Germany)

    2003-07-01

    The method of Discrete Ordinates is in principle parallelizable to a high degree, since the transport 'mesh sweeps' are mutually independent for all angular directions. However, in the well-known production code Dort such a type of angular domain decomposition has to be done on a spatial line-byline basis, causing the parallelism in the code to be very fine-grained. The construction of scalar fluxes and moments requires a large effort for inter-thread or inter-process communication. We have implemented two different parallelization approaches in Dort: firstly, we have used a shared-memory model suitable for SMP (Symmetric Multiprocessor) machines based on the standard OpenMP. The second approach uses the well-known Message Passing Interface (MPI) to establish communication between parallel processes running in a distributed-memory environment. We investigate the benefits and drawbacks of both models and show first results on performance and scaling behaviour of the parallel Dort code. (authors)

  18. PhyloBayes MPI: phylogenetic reconstruction with infinite mixtures of profiles in a parallel environment.

    Science.gov (United States)

    Lartillot, Nicolas; Rodrigue, Nicolas; Stubbs, Daniel; Richer, Jacques

    2013-07-01

    Modeling across site variation of the substitution process is increasingly recognized as important for obtaining more accurate phylogenetic reconstructions. Both finite and infinite mixture models have been proposed and have been shown to significantly improve on classical single-matrix models. Compared with their finite counterparts, infinite mixtures have a greater expressivity. However, they are computationally more challenging. This has resulted in practical compromises in the design of infinite mixture models. In particular, a fast but simplified version of a Dirichlet process model over equilibrium frequency profiles implemented in PhyloBayes has often been used in recent phylogenomics studies, while more refined model structures, more realistic and empirically more fit, have been practically out of reach. We introduce a message passing interface version of PhyloBayes, implementing the Dirichlet process mixture models as well as more classical empirical matrices and finite mixtures. The parallelization is made efficient thanks to the combination of two algorithmic strategies: a partial Gibbs sampling update of the tree topology and the use of a truncated stick-breaking representation for the Dirichlet process prior. The implementation shows close to linear gains in computational speed for up to 64 cores, thus allowing faster phylogenetic reconstruction under complex mixture models. PhyloBayes MPI is freely available from our website www.phylobayes.org.

  19. A Combined MPI-CUDA Parallel Solution of Linear and Nonlinear Poisson-Boltzmann Equation

    Directory of Open Access Journals (Sweden)

    José Colmenares

    2014-01-01

    Full Text Available The Poisson-Boltzmann equation models the electrostatic potential generated by fixed charges on a polarizable solute immersed in an ionic solution. This approach is often used in computational structural biology to estimate the electrostatic energetic component of the assembly of molecular biological systems. In the last decades, the amount of data concerning proteins and other biological macromolecules has remarkably increased. To fruitfully exploit these data, a huge computational power is needed as well as software tools capable of exploiting it. It is therefore necessary to move towards high performance computing and to develop proper parallel implementations of already existing and of novel algorithms. Nowadays, workstations can provide an amazing computational power: up to 10 TFLOPS on a single machine equipped with multiple CPUs and accelerators such as Intel Xeon Phi or GPU devices. The actual obstacle to the full exploitation of modern heterogeneous resources is efficient parallel coding and porting of software on such architectures. In this paper, we propose the implementation of a full Poisson-Boltzmann solver based on a finite-difference scheme using different and combined parallel schemes and in particular a mixed MPI-CUDA implementation. Results show great speedups when using the two schemes, achieving an 18.9x speedup using three GPUs.

  20. Experiences in the parallelization of the discrete ordinates method using OpenMP and MPI

    International Nuclear Information System (INIS)

    Pautz, A.; Langenbuch, S.

    2003-01-01

    The method of Discrete Ordinates is in principle parallelizable to a high degree, since the transport 'mesh sweeps' are mutually independent for all angular directions. However, in the well-known production code Dort such a type of angular domain decomposition has to be done on a spatial line-byline basis, causing the parallelism in the code to be very fine-grained. The construction of scalar fluxes and moments requires a large effort for inter-thread or inter-process communication. We have implemented two different parallelization approaches in Dort: firstly, we have used a shared-memory model suitable for SMP (Symmetric Multiprocessor) machines based on the standard OpenMP. The second approach uses the well-known Message Passing Interface (MPI) to establish communication between parallel processes running in a distributed-memory environment. We investigate the benefits and drawbacks of both models and show first results on performance and scaling behaviour of the parallel Dort code. (authors)

  1. Study on High Performance of MPI-Based Parallel FDTD from WorkStation to Super Computer Platform

    Directory of Open Access Journals (Sweden)

    Z. L. He

    2012-01-01

    Full Text Available Parallel FDTD method is applied to analyze the electromagnetic problems of the electrically large targets on super computer. It is well known that the more the number of processors the less computing time consumed. Nevertheless, with the same number of processors, computing efficiency is affected by the scheme of the MPI virtual topology. Then, the influence of different virtual topology schemes on parallel performance of parallel FDTD is studied in detail. The general rules are presented on how to obtain the highest efficiency of parallel FDTD algorithm by optimizing MPI virtual topology. To show the validity of the presented method, several numerical results are given in the later part. Various comparisons are made and some useful conclusions are summarized.

  2. Thermodynamic behavior of binary mixtures CnMpyNTf2 ionic liquids with primary and secondary alcohols

    International Nuclear Information System (INIS)

    Calvar, N.; Gómez, E.; Domínguez, Á.; Macedo, E.A.

    2012-01-01

    Highlights: ► Osmotic coefficients of alcohols with C n MpyNTf 2 (n = 2, 3, 4) are determined. ► Experimental data were correlated with Extended Pitzer model of Archer and MNRTL. ► Mean molal activity coefficients and excess Gibbs free energies were calculated. ► The results have been interpreted in terms of interactions. - Abstract: In this paper, the osmotic and activity coefficients and vapor pressures of the binary mixtures containing the ionic liquids 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C 2 MpyNTf 2 , and 1-methyl-3-propylpyridinium bis(trifluoromethylsulfonyl)imide, C 3 MpyNTf 2 , with 1-propanol, or 2-propanol and the ionic liquid 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C 4 MpyNTf 2 , with 1-propanol or 2-propanol or 1-butanol or 2-butanol were determined at T = 323.15 K using the vapor pressure osmometry technique. The influence of the structure of the alcohol and of the ionic liquid on both coefficients and vapor pressures is discussed and a comparison with literature data on binary mixtures containing ionic liquids with different cations and anion is also performed. Besides, the results have been interpreted in terms of solute–solvent and ion–ion interactions. The experimental osmotic coefficients were correlated using the Extended Pitzer model of Archer and the Modified Non-Random Two Liquids model obtaining standard deviations lower than 0.059 and 0.102 respectively, and the mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated.

  3. McMPI – a managed-code message passing interface library for high performance communication in C#

    OpenAIRE

    Holmes, Daniel John

    2012-01-01

    This work endeavours to achieve technology transfer between established best-practice in academic high-performance computing and current techniques in commercial high-productivity computing. It shows that a credible high-performance message-passing communication library, with semantics and syntax following the Message-Passing Interface (MPI) Standard, can be built in pure C# (one of the .Net suite of computer languages). Message-passing has been the dominant paradigm in high-pe...

  4. Novel magnetic multicore nanoparticles designed for MPI and other biomedical applications: From synthesis to first in vivo studies.

    Directory of Open Access Journals (Sweden)

    Harald Kratz

    Full Text Available Synthesis of novel magnetic multicore particles (MCP in the nano range, involves alkaline precipitation of iron(II chloride in the presence of atmospheric oxygen. This step yields green rust, which is oxidized to obtain magnetic nanoparticles, which probably consist of a magnetite/maghemite mixed-phase. Final growth and annealing at 90°C in the presence of a large excess of carboxymethyl dextran gives MCP very promising magnetic properties for magnetic particle imaging (MPI, an emerging medical imaging modality, and magnetic resonance imaging (MRI. The magnetic nanoparticles are biocompatible and thus potential candidates for future biomedical applications such as cardiovascular imaging, sentinel lymph node mapping in cancer patients, and stem cell tracking. The new MCP that we introduce here have three times higher magnetic particle spectroscopy performance at lower and middle harmonics and five times higher MPS signal strength at higher harmonics compared with Resovist®. In addition, the new MCP have also an improved in vivo MPI performance compared to Resovist®, and we here report the first in vivo MPI investigation of this new generation of magnetic nanoparticles.

  5. MPI-AMRVAC 2.0 for Solar and Astrophysical Applications

    Science.gov (United States)

    Xia, C.; Teunissen, J.; El Mellah, I.; Chané, E.; Keppens, R.

    2018-02-01

    We report on the development of MPI-AMRVAC version 2.0, which is an open-source framework for parallel, grid-adaptive simulations of hydrodynamic and magnetohydrodynamic (MHD) astrophysical applications. The framework now supports radial grid stretching in combination with adaptive mesh refinement (AMR). The advantages of this combined approach are demonstrated with one-dimensional, two-dimensional, and three-dimensional examples of spherically symmetric Bondi accretion, steady planar Bondi–Hoyle–Lyttleton flows, and wind accretion in supergiant X-ray binaries. Another improvement is support for the generic splitting of any background magnetic field. We present several tests relevant for solar physics applications to demonstrate the advantages of field splitting on accuracy and robustness in extremely low-plasma β environments: a static magnetic flux rope, a magnetic null-point, and magnetic reconnection in a current sheet with either uniform or anomalous resistivity. Our implementation for treating anisotropic thermal conduction in multi-dimensional MHD applications is also described, which generalizes the original slope-limited symmetric scheme from two to three dimensions. We perform ring diffusion tests that demonstrate its accuracy and robustness, and show that it prevents the unphysical thermal flux present in traditional schemes. The improved parallel scaling of the code is demonstrated with three-dimensional AMR simulations of solar coronal rain, which show satisfactory strong scaling up to 2000 cores. Other framework improvements are also reported: the modernization and reorganization into a library, the handling of automatic regression tests, the use of inline/online Doxygen documentation, and a new future-proof data format for input/output.

  6. Applications Performance Under MPL and MPI on NAS IBM SP2

    Science.gov (United States)

    Saini, Subhash; Simon, Horst D.; Lasinski, T. A. (Technical Monitor)

    1994-01-01

    On July 5, 1994, an IBM Scalable POWER parallel System (IBM SP2) with 64 nodes, was installed at the Numerical Aerodynamic Simulation (NAS) Facility Each node of NAS IBM SP2 is a "wide node" consisting of a RISC 6000/590 workstation module with a clock of 66.5 MHz which can perform four floating point operations per clock with a peak performance of 266 Mflop/s. By the end of 1994, 64 nodes of IBM SP2 will be upgraded to 160 nodes with a peak performance of 42.5 Gflop/s. An overview of the IBM SP2 hardware is presented. The basic understanding of architectural details of RS 6000/590 will help application scientists the porting, optimizing, and tuning of codes from other machines such as the CRAY C90 and the Paragon to the NAS SP2. Optimization techniques such as quad-word loading, effective utilization of two floating point units, and data cache optimization of RS 6000/590 is illustrated, with examples giving performance gains at each optimization step. The conversion of codes using Intel's message passing library NX to codes using native Message Passing Library (MPL) and the Message Passing Interface (NMI) library available on the IBM SP2 is illustrated. In particular, we will present the performance of Fast Fourier Transform (FFT) kernel from NAS Parallel Benchmarks (NPB) under MPL and MPI. We have also optimized some of Fortran BLAS 2 and BLAS 3 routines, e.g., the optimized Fortran DAXPY runs at 175 Mflop/s and optimized Fortran DGEMM runs at 230 Mflop/s per node. The performance of the NPB (Class B) on the IBM SP2 is compared with the CRAY C90, Intel Paragon, TMC CM-5E, and the CRAY T3D.

  7. GASFLOW-MPI. A scalable computational fluid dynamics code for gases, aerosols and combustion. Vol. 2. Users' manual (Revision 1.0)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Jianjun; Travis, Jack; Royl, Peter; Necker, Gottfried; Svishchev, Anatoly; Jordan, Thomas

    2016-07-01

    Karlsruhe Institute of Technology (KIT) is developing the parallel computational fluid dynamics code GASFLOW-MPI as a best-estimate tool for predicting transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containments and other facility buildings. GASFLOW-MPI is a finite-volume code based on proven computational fluid dynamics methodology that solves the compressible Navier-Stokes equations for three-dimensional volumes in Cartesian or cylindrical coordinates.

  8. GASFLOW-MPI. A scalable computational fluid dynamics code for gases, aerosols and combustion. Vol. 1. Theory and computational model (Revision 1.0)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Jianjun; Travis, Jack; Royl, Peter; Necker, Gottfried; Svishchev, Anatoly; Jordan, Thomas

    2016-07-01

    Karlsruhe Institute of Technology (KIT) is developing the parallel computational fluid dynamics code GASFLOW-MPI as a best-estimate tool for predicting transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containments and other facility buildings. GASFLOW-MPI is a finite-volume code based on proven computational fluid dynamics methodology that solves the compressible Navier-Stokes equations for three-dimensional volumes in Cartesian or cylindrical coordinates.

  9. MPI version of NJOY and its application to multigroup cross-section generation

    Energy Technology Data Exchange (ETDEWEB)

    Alpan, A.; Haghighat, A.

    1999-07-01

    , temperatures assigned for broadening, or the number of fine energy groups. To speed up the process of multigroup cross-section generation, the NJOY code has been parallelized using the message passing interface (MPI) library.

  10. MPI version of NJOY and its application to multigroup cross-section generation

    International Nuclear Information System (INIS)

    Alpan, A.; Haghighat, A.

    1999-01-01

    assigned for broadening, or the number of fine energy groups. To speed up the process of multigroup cross-section generation, the NJOY code has been parallelized using the message passing interface (MPI) library

  11. An approach to computing discrete adjoints for MPI-parallelized models applied to Ice Sheet System Model 4.11

    Directory of Open Access Journals (Sweden)

    E. Larour

    2016-11-01

    Full Text Available Within the framework of sea-level rise projections, there is a strong need for hindcast validation of the evolution of polar ice sheets in a way that tightly matches observational records (from radar, gravity, and altimetry observations mainly. However, the computational requirements for making hindcast reconstructions possible are severe and rely mainly on the evaluation of the adjoint state of transient ice-flow models. Here, we look at the computation of adjoints in the context of the NASA/JPL/UCI Ice Sheet System Model (ISSM, written in C++ and designed for parallel execution with MPI. We present the adaptations required in the way the software is designed and written, but also generic adaptations in the tools facilitating the adjoint computations. We concentrate on the use of operator overloading coupled with the AdjoinableMPI library to achieve the adjoint computation of the ISSM. We present a comprehensive approach to (1 carry out type changing through the ISSM, hence facilitating operator overloading, (2 bind to external solvers such as MUMPS and GSL-LU, and (3 handle MPI-based parallelism to scale the capability. We demonstrate the success of the approach by computing sensitivities of hindcast metrics such as the misfit to observed records of surface altimetry on the northeastern Greenland Ice Stream, or the misfit to observed records of surface velocities on Upernavik Glacier, central West Greenland. We also provide metrics for the scalability of the approach, and the expected performance. This approach has the potential to enable a new generation of hindcast-validated projections that make full use of the wealth of datasets currently being collected, or already collected, in Greenland and Antarctica.

  12. Utilization of the MPI Process for in-tank solidification of heel material in large-diameter cylindrical tanks

    Energy Technology Data Exchange (ETDEWEB)

    Kauschinger, J.L.; Lewis, B.E.

    2000-01-01

    A major problem faced by the US Department of Energy is remediation of sludge and supernatant waste in underground storage tanks. Exhumation of the waste is currently the preferred remediation method. However, exhumation cannot completely remove all of the contaminated materials from the tanks. For large-diameter tanks, amounts of highly contaminated ``heel'' material approaching 20,000 gal can remain. Often sludge containing zeolite particles leaves ``sand bars'' of locally contaminated material across the floor of the tank. The best management practices for in-tank treatment (stabilization and immobilization) of wastes require an integrated approach to develop appropriate treatment agents that can be safely delivered and mixed uniformly with sludge. Ground Environmental Services has developed and demonstrated a remotely controlled, high-velocity jet delivery system termed, Multi-Point-Injection (MPI). This robust jet delivery system has been field-deployed to create homogeneous monoliths containing shallow buried miscellaneous waste in trenches [fiscal year (FY) 1995] and surrogate sludge in cylindrical (FY 1998) and long, horizontal tanks (FY 1999). During the FY 1998 demonstration, the MPI process successfully formed a 32-ton uniform monolith of grout and waste surrogates in about 8 min. Analytical data indicated that 10 tons of zeolite-type physical surrogate were uniformly mixed within a 40-in.-thick monolith without lifting the MPI jetting tools off the tank floor. Over 1,000 lb of cohesive surrogates, with consistencies similar to Gunite and Associated Tank (GAAT) TH-4 and Hanford tank sludges, were easily intermixed into the monolith without exceeding a core temperature of 100 F during curing.

  13. How to stir a revolution as a reluctant rebel: Rudolf Trümpy in the Alps

    Science.gov (United States)

    Şengör, A. M. Celâl; Bernoulli, Daniel

    2011-07-01

    Rudolf Trümpy (1921-2009) was one of the great Alpine geologists of the twentieth century and an influential figure in the international geological community. He played a dominant role in the change of opinion concerning the Alpine evolution by showing that normal faulting dominated the early development of the Alpine realm from the Triassic to the early Cretaceous. This provided a convenient model for later plate-tectonic interpretations of collisional mountain belts. His further recognition of strike-slip faulting during all stages of the Alpine evolution presaged the realisation that the Alps were not built by a simple open-and-shut mechanism. Trümpy was educated during an intellectual lull, a time when simplistic models of the earth behaviour inherited from the middle of the nineteenth century became prevalent under the influence of a close-minded, positivist approach to geological problems. This period, which we term the Dark Intermezzo, lasted from about 1925 to 1965. The grand syntheses of Suess and Argand which preceded this period were viewed from this narrow angle and consequently misunderstood. It was thought that earth history was punctuated by global orogenic events of short duration taking place within and among continents and oceans whose relative positions had remained fixed since the origin of the planet. These views, summarised under the term `fixism', were developed when the ocean floors were almost totally unknown. When data began coming in from the post World War II oceanographic surveys, the world geological community was slow to receive and digest them. Trümpy followed these developments closely, realising that his work was important in placing the geology of the mountain belts within the emerging, new theoretical framework. He adopted the position of a critic and emphasised where detailed knowledge of the Alps, unquestionably the best known mountain belt in the world, supported and where it contradicted the new ideas. His voice was

  14. Coupling Computer Codes for The Analysis of Severe Accident Using A Pseudo Shared Memory Based on MPI

    International Nuclear Information System (INIS)

    Cho, Young Chul; Park, Chang-Hwan; Kim, Dong-Min

    2016-01-01

    As there are four codes in-vessel analysis code (CSPACE), ex-vessel analysis code (SACAP), corium behavior analysis code (COMPASS), and fission product behavior analysis code, for the analysis of severe accident, it is complex to implement the coupling of codes with the similar methodologies for RELAP and CONTEMPT or SPACE and CAP. Because of that, an efficient coupling so called Pseudo shared memory architecture was introduced. In this paper, coupling methodologies will be compared and the methodology used for the analysis of severe accident will be discussed in detail. The barrier between in-vessel and ex-vessel has been removed for the analysis of severe accidents with the implementation of coupling computer codes with pseudo shared memory architecture based on MPI. The remaining are proper choice and checking of variables and values for the selected severe accident scenarios, e.g., TMI accident. Even though it is possible to couple more than two computer codes with pseudo shared memory architecture, the methodology should be revised to couple parallel codes especially when they are programmed using MPI

  15. Coupling Computer Codes for The Analysis of Severe Accident Using A Pseudo Shared Memory Based on MPI

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Chul; Park, Chang-Hwan; Kim, Dong-Min [FNC Technology Co., Yongin (Korea, Republic of)

    2016-10-15

    As there are four codes in-vessel analysis code (CSPACE), ex-vessel analysis code (SACAP), corium behavior analysis code (COMPASS), and fission product behavior analysis code, for the analysis of severe accident, it is complex to implement the coupling of codes with the similar methodologies for RELAP and CONTEMPT or SPACE and CAP. Because of that, an efficient coupling so called Pseudo shared memory architecture was introduced. In this paper, coupling methodologies will be compared and the methodology used for the analysis of severe accident will be discussed in detail. The barrier between in-vessel and ex-vessel has been removed for the analysis of severe accidents with the implementation of coupling computer codes with pseudo shared memory architecture based on MPI. The remaining are proper choice and checking of variables and values for the selected severe accident scenarios, e.g., TMI accident. Even though it is possible to couple more than two computer codes with pseudo shared memory architecture, the methodology should be revised to couple parallel codes especially when they are programmed using MPI.

  16. Performance Comparison of a Matrix Solver on a Heterogeneous Network Using Two Implementations of MPI: MPICH and LAM

    Science.gov (United States)

    Phillips, Jennifer K.

    1995-01-01

    Two of the current and most popular implementations of the Message-Passing Standard, Message Passing Interface (MPI), were contrasted: MPICH by Argonne National Laboratory, and LAM by the Ohio Supercomputer Center at Ohio State University. A parallel skyline matrix solver was adapted to be run in a heterogeneous environment using MPI. The Message-Passing Interface Forum was held in May 1994 which lead to a specification of library functions that implement the message-passing model of parallel communication. LAM, which creates it's own environment, is more robust in a highly heterogeneous network. MPICH uses the environment native to the machine architecture. While neither of these free-ware implementations provides the performance of native message-passing or vendor's implementations, MPICH begins to approach that performance on the SP-2. The machines used in this study were: IBM RS6000, 3 Sun4, SGI, and the IBM SP-2. Each machine is unique and a few machines required specific modifications during the installation. When installed correctly, both implementations worked well with only minor problems.

  17. Parallel Fortran-MPI software for numerical inversion of the Laplace transform and its application to oscillatory water levels in groundwater environments

    Science.gov (United States)

    Zhan, X.

    2005-01-01

    A parallel Fortran-MPI (Message Passing Interface) software for numerical inversion of the Laplace transform based on a Fourier series method is developed to meet the need of solving intensive computational problems involving oscillatory water level's response to hydraulic tests in a groundwater environment. The software is a parallel version of ACM (The Association for Computing Machinery) Transactions on Mathematical Software (TOMS) Algorithm 796. Running 38 test examples indicated that implementation of MPI techniques with distributed memory architecture speedups the processing and improves the efficiency. Applications to oscillatory water levels in a well during aquifer tests are presented to illustrate how this package can be applied to solve complicated environmental problems involved in differential and integral equations. The package is free and is easy to use for people with little or no previous experience in using MPI but who wish to get off to a quick start in parallel computing. ?? 2004 Elsevier Ltd. All rights reserved.

  18. Matrix Factorizations at Scale: a Comparison of Scientific Data Analytics in Spark and C+MPI Using Three Case Studies

    Energy Technology Data Exchange (ETDEWEB)

    Gittens, Alex; Devarakonda, Aditya; Racah, Evan; Ringenburg, Michael; Gerhardt, Lisa; Kottalam, Jey; Liu, Jialin; Maschhoff, Kristyn; Canon, Shane; Chhugani, Jatin; Sharma, Pramod; Yang, Jiyan; Demmel, James; Harrell, Jim; Krishnamurthy, Venkat; Mahoney, Michael; Prabhat, Mr

    2016-05-12

    We explore the trade-offs of performing linear algebra using Apache Spark, compared to traditional C and MPI implementations on HPC platforms. Spark is designed for data analytics on cluster computing platforms with access to local disks and is optimized for data-parallel tasks. We examine three widely-used and important matrix factorizations: NMF (for physical plausibility), PCA (for its ubiquity) and CX (for data interpretability). We apply these methods to 1.6TB particle physics, 2.2TB and 16TB climate modeling and 1.1TB bioimaging data. The data matrices are tall-and-skinny which enable the algorithms to map conveniently into Spark’s data parallel model. We perform scaling experiments on up to 1600 Cray XC40 nodes, describe the sources of slowdowns, and provide tuning guidance to obtain high performance.

  19. Hybrid MPI-OpenMP Parallelism in the ONETEP Linear-Scaling Electronic Structure Code: Application to the Delamination of Cellulose Nanofibrils.

    Science.gov (United States)

    Wilkinson, Karl A; Hine, Nicholas D M; Skylaris, Chris-Kriton

    2014-11-11

    We present a hybrid MPI-OpenMP implementation of Linear-Scaling Density Functional Theory within the ONETEP code. We illustrate its performance on a range of high performance computing (HPC) platforms comprising shared-memory nodes with fast interconnect. Our work has focused on applying OpenMP parallelism to the routines which dominate the computational load, attempting where possible to parallelize different loops from those already parallelized within MPI. This includes 3D FFT box operations, sparse matrix algebra operations, calculation of integrals, and Ewald summation. While the underlying numerical methods are unchanged, these developments represent significant changes to the algorithms used within ONETEP to distribute the workload across CPU cores. The new hybrid code exhibits much-improved strong scaling relative to the MPI-only code and permits calculations with a much higher ratio of cores to atoms. These developments result in a significantly shorter time to solution than was possible using MPI alone and facilitate the application of the ONETEP code to systems larger than previously feasible. We illustrate this with benchmark calculations from an amyloid fibril trimer containing 41,907 atoms. We use the code to study the mechanism of delamination of cellulose nanofibrils when undergoing sonification, a process which is controlled by a large number of interactions that collectively determine the structural properties of the fibrils. Many energy evaluations were needed for these simulations, and as these systems comprise up to 21,276 atoms this would not have been feasible without the developments described here.

  20. Mixing thermodynamic properties of 1-butyl-4-methylpyridinium tetrafluoroborate [b4mpy][BF{sub 4}] with water and with an alkan-1ol (methanol to pentanol)

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J. [Laboratorio de Termodinamica y Fisicoquimica de Fluidos, Parque Cientifico-Tecnologico, Campus Universitario de Tafira, Universidad de Las Palmas de Gran Canaria, 35071-Las Palmas de Gran Canaria, Canary Islands (Spain)], E-mail: jortega@dip.ulpgc.es; Vreekamp, R.; Penco, E.; Marrero, E. [Laboratorio de Termodinamica y Fisicoquimica de Fluidos, Parque Cientifico-Tecnologico, Campus Universitario de Tafira, Universidad de Las Palmas de Gran Canaria, 35071-Las Palmas de Gran Canaria, Canary Islands (Spain)

    2008-07-15

    This article presents a study of the behaviour in solution of 1-butyl-4-methylpyridinium tetrafluoroborate [b4mpy][BF{sub 4}] in water and in the first five alkanols of the series methanol to pentan-1-ol. The excess enthalpies, H{sub m}{sup E} and volumes, V{sub m}{sup E} were determined at the temperatures (298.15 and 318.15) K. At these temperatures, the [b4mpy][BF{sub 4}] was completely miscible in water, methanol, and ethanol, but only partially miscible in the other alkanols. A solubility study was carried out and the (liquid + liquid) equilibria of the ([b4mpy][BF{sub 4}] + alkanol) systems were experimentally determined, evaluating zones of complete miscibility and determining the UCST in each case. The mixtures with water gave positive values of H{sub m}{sup E} and V{sub m}{sup E}, being also positive the changes of these quantities with temperature. The mixtures with alkanols gave values of H{sub m}{sup E}>0 and V{sub m}{sup E}<0, and for these binary mixtures (dH{sub m}{sup E}/dT){sub p}>0 and (dV{sub m}{sup E}/dT){sub p}<0. For all cases, results were interpreted and compared with data obtained in mixtures with another isomer [b3mpy][BF{sub 4}]. Excess properties were correlated with a suitable equation and the area and volume parameters were calculated for [b4mpy][BF{sub 4}].

  1. Vegetation and land carbon feedbacks in the high-resolution transient Holocene simulations using the MPI Earth system model

    Science.gov (United States)

    Brovkin, Victor; Lorenz, Stephan; Raddatz, Thomas

    2017-04-01

    Plants influence climate through changes in the land surface biophysics (albedo, transpiration) and concentrations of the atmospheric greenhouse gases. One of the interesting periods to investigate a climatic role of terrestrial biosphere is the Holocene, when, despite of the relatively steady global climate, the atmospheric CO2 grew by about 20 ppm from 7 kyr BP to pre-industrial. We use a new setup of the Max Planck Institute Earth System Model MPI-ESM1 consisting of the latest version of the atmospheric model ECHAM6, including the land surface model JSBACH3 with carbon cycle and vegetation dynamics, coupled to the ocean circulation model MPI-OM, which includes the HAMOCC model of ocean biogeochemistry. The model has been run for several simulations over the Holocene period of the last 8000 years under the forcing data sets of orbital insolation, atmospheric greenhouse gases, volcanic aerosols, solar irradiance and stratospheric ozone, as well as land-use changes. In response to this forcing, the land carbon storage increased by about 60 PgC between 8 and 4 kyr BP, stayed relatively constant until 2 kyr BP, and decreased by about 90 PgC by 1850 AD due to land use changes. Vegetation and soil carbon changes significantly affected atmospheric CO2 during the periods of strong volcanic eruptions. In response to the eruption-caused cooling, the land initially stores more carbon as respiration decreases, but then it releases even more carbon due to productivity decrease. This decadal- scale variability helps to quantify the vegetation and land carbon feedbacks during the past periods when the temporal resolution of the ice-core CO2 record is not sufficient to capture fast CO2 variations. From a set of Holocene simulations with prescribed or interactive atmospheric CO2, we get estimates of climate-carbon feedback useful for future climate studies. Members of the Hamburg Holocene Team: Jürgen Bader1, Sebastian Bathiany2, Victor Brovkin1, Martin Claussen1,3, Traute Cr

  2. Vegetation and Carbon Cycle Dynamics in the High-Resolution Transient Holocene Simulations Using the MPI Earth System Model

    Science.gov (United States)

    Brovkin, V.; Lorenz, S.; Raddatz, T.; Claussen, M.; Dallmeyer, A.

    2017-12-01

    One of the interesting periods to investigate a climatic role of terrestrial biosphere is the Holocene, when, despite of the relatively steady global climate, the atmospheric CO2 grew by about 20 ppm from 7 kyr BP to pre-industrial. We use a new setup of the Max Planck Institute Earth System Model MPI-ESM1 consisting of the latest version of the atmospheric model ECHAM6, including the land surface model JSBACH3 with carbon cycle and vegetation dynamics, coupled to the ocean circulation model MPI-OM, which includes the HAMOCC model of ocean biogeochemistry. The model has been run for several simulations over the Holocene period of the last 8000 years under the forcing data sets of orbital insolation, atmospheric greenhouse gases, volcanic aerosols, solar irradiance and stratospheric ozone, as well as land-use changes. In response to this forcing, the land carbon storage increased by about 60 PgC between 8 and 4 kyr BP, stayed relatively constant until 2 kyr BP, and decreased by about 90 PgC by 1850 AD due to land use changes. At 8 kyr BP, vegetation cover was much denser in Africa, mainly due to increased rainfall in response to the orbital forcing. Boreal forests moved northward in both, North America and Eurasia. The boreal forest expansion in North America is much less pronounced than in Eurasia. Simulated physical ocean fields, including surface temperatures and meridional overturning, do not change substantially in the Holocene. Carbonate ion concentration in deep ocean decreases in both, prescribed and interactive CO2simulations. Comparison with available proxies for terrestrial vegetation and for the ocean carbonate chemistry will be presented. Vegetation and soil carbon changes significantly affected atmospheric CO2 during the periods of strong volcanic eruptions. In response to the eruption-caused cooling, the land initially stores more carbon as respiration decreases, but then it releases even more carbon die to productivity decrease. This decadal

  3. The prediction of surface temperature in the new seasonal prediction system based on the MPI-ESM coupled climate model

    Science.gov (United States)

    Baehr, J.; Fröhlich, K.; Botzet, M.; Domeisen, D. I. V.; Kornblueh, L.; Notz, D.; Piontek, R.; Pohlmann, H.; Tietsche, S.; Müller, W. A.

    2015-05-01

    A seasonal forecast system is presented, based on the global coupled climate model MPI-ESM as used for CMIP5 simulations. We describe the initialisation of the system and analyse its predictive skill for surface temperature. The presented system is initialised in the atmospheric, oceanic, and sea ice component of the model from reanalysis/observations with full field nudging in all three components. For the initialisation of the ensemble, bred vectors with a vertically varying norm are implemented in the ocean component to generate initial perturbations. In a set of ensemble hindcast simulations, starting each May and November between 1982 and 2010, we analyse the predictive skill. Bias-corrected ensemble forecasts for each start date reproduce the observed surface temperature anomalies at 2-4 months lead time, particularly in the tropics. Niño3.4 sea surface temperature anomalies show a small root-mean-square error and predictive skill up to 6 months. Away from the tropics, predictive skill is mostly limited to the ocean, and to regions which are strongly influenced by ENSO teleconnections. In summary, the presented seasonal prediction system based on a coupled climate model shows predictive skill for surface temperature at seasonal time scales comparable to other seasonal prediction systems using different underlying models and initialisation strategies. As the same model underlying our seasonal prediction system—with a different initialisation—is presently also used for decadal predictions, this is an important step towards seamless seasonal-to-decadal climate predictions.

  4. An efficient MPI/OpenMP parallelization of the Hartree–Fock–Roothaan method for the first generation of Intel® Xeon Phi™ processor architecture

    International Nuclear Information System (INIS)

    Mironov, Vladimir; Moskovsky, Alexander; D’Mello, Michael; Alexeev, Yuri

    2017-01-01

    The Hartree-Fock (HF) method in the quantum chemistry package GAMESS represents one of the most irregular algorithms in computation today. Major steps in the calculation are the irregular computation of electron repulsion integrals (ERIs) and the building of the Fock matrix. These are the central components of the main Self Consistent Field (SCF) loop, the key hotspot in Electronic Structure (ES) codes. By threading the MPI ranks in the official release of the GAMESS code, we not only speed up the main SCF loop (4x to 6x for large systems), but also achieve a significant (>2x) reduction in the overall memory footprint. These improvements are a direct consequence of memory access optimizations within the MPI ranks. We benchmark our implementation against the official release of the GAMESS code on the Intel R Xeon PhiTM supercomputer. Here, scaling numbers are reported on up to 7,680 cores on Intel Xeon Phi coprocessors.

  5. WImpiBLAST: web interface for mpiBLAST to help biologists perform large-scale annotation using high performance computing.

    Directory of Open Access Journals (Sweden)

    Parichit Sharma

    Full Text Available The function of a newly sequenced gene can be discovered by determining its sequence homology with known proteins. BLAST is the most extensively used sequence analysis program for sequence similarity search in large databases of sequences. With the advent of next generation sequencing technologies it has now become possible to study genes and their expression at a genome-wide scale through RNA-seq and metagenome sequencing experiments. Functional annotation of all the genes is done by sequence similarity search against multiple protein databases. This annotation task is computationally very intensive and can take days to obtain complete results. The program mpiBLAST, an open-source parallelization of BLAST that achieves superlinear speedup, can be used to accelerate large-scale annotation by using supercomputers and high performance computing (HPC clusters. Although many parallel bioinformatics applications using the Message Passing Interface (MPI are available in the public domain, researchers are reluctant to use them due to lack of expertise in the Linux command line and relevant programming experience. With these limitations, it becomes difficult for biologists to use mpiBLAST for accelerating annotation. No web interface is available in the open-source domain for mpiBLAST. We have developed WImpiBLAST, a user-friendly open-source web interface for parallel BLAST searches. It is implemented in Struts 1.3 using a Java backbone and runs atop the open-source Apache Tomcat Server. WImpiBLAST supports script creation and job submission features and also provides a robust job management interface for system administrators. It combines script creation and modification features with job monitoring and management through the Torque resource manager on a Linux-based HPC cluster. Use case information highlights the acceleration of annotation analysis achieved by using WImpiBLAST. Here, we describe the WImpiBLAST web interface features and architecture

  6. WImpiBLAST: web interface for mpiBLAST to help biologists perform large-scale annotation using high performance computing.

    Science.gov (United States)

    Sharma, Parichit; Mantri, Shrikant S

    2014-01-01

    The function of a newly sequenced gene can be discovered by determining its sequence homology with known proteins. BLAST is the most extensively used sequence analysis program for sequence similarity search in large databases of sequences. With the advent of next generation sequencing technologies it has now become possible to study genes and their expression at a genome-wide scale through RNA-seq and metagenome sequencing experiments. Functional annotation of all the genes is done by sequence similarity search against multiple protein databases. This annotation task is computationally very intensive and can take days to obtain complete results. The program mpiBLAST, an open-source parallelization of BLAST that achieves superlinear speedup, can be used to accelerate large-scale annotation by using supercomputers and high performance computing (HPC) clusters. Although many parallel bioinformatics applications using the Message Passing Interface (MPI) are available in the public domain, researchers are reluctant to use them due to lack of expertise in the Linux command line and relevant programming experience. With these limitations, it becomes difficult for biologists to use mpiBLAST for accelerating annotation. No web interface is available in the open-source domain for mpiBLAST. We have developed WImpiBLAST, a user-friendly open-source web interface for parallel BLAST searches. It is implemented in Struts 1.3 using a Java backbone and runs atop the open-source Apache Tomcat Server. WImpiBLAST supports script creation and job submission features and also provides a robust job management interface for system administrators. It combines script creation and modification features with job monitoring and management through the Torque resource manager on a Linux-based HPC cluster. Use case information highlights the acceleration of annotation analysis achieved by using WImpiBLAST. Here, we describe the WImpiBLAST web interface features and architecture, explain design

  7. A comprehensive study of MPI parallelism in three-dimensional discrete element method (DEM) simulation of complex-shaped granular particles

    Science.gov (United States)

    Yan, Beichuan; Regueiro, Richard A.

    2018-02-01

    A three-dimensional (3D) DEM code for simulating complex-shaped granular particles is parallelized using message-passing interface (MPI). The concepts of link-block, ghost/border layer, and migration layer are put forward for design of the parallel algorithm, and theoretical scalability function of 3-D DEM scalability and memory usage is derived. Many performance-critical implementation details are managed optimally to achieve high performance and scalability, such as: minimizing communication overhead, maintaining dynamic load balance, handling particle migrations across block borders, transmitting C++ dynamic objects of particles between MPI processes efficiently, eliminating redundant contact information between adjacent MPI processes. The code executes on multiple US Department of Defense (DoD) supercomputers and tests up to 2048 compute nodes for simulating 10 million three-axis ellipsoidal particles. Performance analyses of the code including speedup, efficiency, scalability, and granularity across five orders of magnitude of simulation scale (number of particles) are provided, and they demonstrate high speedup and excellent scalability. It is also discovered that communication time is a decreasing function of the number of compute nodes in strong scaling measurements. The code's capability of simulating a large number of complex-shaped particles on modern supercomputers will be of value in both laboratory studies on micromechanical properties of granular materials and many realistic engineering applications involving granular materials.

  8. Performance Characteristics of Hybrid MPI/OpenMP Scientific Applications on a Large-Scale Multithreaded BlueGene/Q Supercomputer

    KAUST Repository

    Wu, Xingfu; Taylor, Valerie

    2013-01-01

    In this paper, we investigate the performance characteristics of five hybrid MPI/OpenMP scientific applications (two NAS Parallel benchmarks Multi-Zone SP-MZ and BT-MZ, an earthquake simulation PEQdyna, an aerospace application PMLB and a 3D particle-in-cell application GTC) on a large-scale multithreaded Blue Gene/Q supercomputer at Argonne National laboratory, and quantify the performance gap resulting from using different number of threads per node. We use performance tools and MPI profile and trace libraries available on the supercomputer to analyze and compare the performance of these hybrid scientific applications with increasing the number OpenMP threads per node, and find that increasing the number of threads to some extent saturates or worsens performance of these hybrid applications. For the strong-scaling hybrid scientific applications such as SP-MZ, BT-MZ, PEQdyna and PLMB, using 32 threads per node results in much better application efficiency than using 64 threads per node, and as increasing the number of threads per node, the FPU (Floating Point Unit) percentage decreases, and the MPI percentage (except PMLB) and IPC (Instructions per cycle) per core (except BT-MZ) increase. For the weak-scaling hybrid scientific application such as GTC, the performance trend (relative speedup) is very similar with increasing number of threads per node no matter how many nodes (32, 128, 512) are used. © 2013 IEEE.

  9. Performance Characteristics of Hybrid MPI/OpenMP Scientific Applications on a Large-Scale Multithreaded BlueGene/Q Supercomputer

    KAUST Repository

    Wu, Xingfu

    2013-07-01

    In this paper, we investigate the performance characteristics of five hybrid MPI/OpenMP scientific applications (two NAS Parallel benchmarks Multi-Zone SP-MZ and BT-MZ, an earthquake simulation PEQdyna, an aerospace application PMLB and a 3D particle-in-cell application GTC) on a large-scale multithreaded Blue Gene/Q supercomputer at Argonne National laboratory, and quantify the performance gap resulting from using different number of threads per node. We use performance tools and MPI profile and trace libraries available on the supercomputer to analyze and compare the performance of these hybrid scientific applications with increasing the number OpenMP threads per node, and find that increasing the number of threads to some extent saturates or worsens performance of these hybrid applications. For the strong-scaling hybrid scientific applications such as SP-MZ, BT-MZ, PEQdyna and PLMB, using 32 threads per node results in much better application efficiency than using 64 threads per node, and as increasing the number of threads per node, the FPU (Floating Point Unit) percentage decreases, and the MPI percentage (except PMLB) and IPC (Instructions per cycle) per core (except BT-MZ) increase. For the weak-scaling hybrid scientific application such as GTC, the performance trend (relative speedup) is very similar with increasing number of threads per node no matter how many nodes (32, 128, 512) are used. © 2013 IEEE.

  10. Portable and Transparent Message Compression in MPI Libraries to Improve the Performance and Scalability of Parallel Applications

    Energy Technology Data Exchange (ETDEWEB)

    Albonesi, David; Burtscher, Martin

    2009-04-17

    The goal of this project has been to develop a lossless compression algorithm for message-passing libraries that can accelerate HPC systems by reducing the communication time. Because both compression and decompression have to be performed in software in real time, the algorithm has to be extremely fast while still delivering a good compression ratio. During the first half of this project, they designed a new compression algorithm called FPC for scientific double-precision data, made the source code available on the web, and published two papers describing its operation, the first in the proceedings of the Data Compression Conference and the second in the IEEE Transactions on Computers. At comparable average compression ratios, this algorithm compresses and decompresses 10 to 100 times faster than BZIP2, DFCM, FSD, GZIP, and PLMI on the three architectures tested. With prediction tables that fit into the CPU's L1 data acache, FPC delivers a guaranteed throughput of six gigabits per second on a 1.6 GHz Itanium 2 system. The C source code and documentation of FPC are posted on-line and have already been downloaded hundreds of times. To evaluate FPC, they gathered 13 real-world scientific datasets from around the globe, including satellite data, crash-simulation data, and messages from HPC systems. Based on the large number of requests they received, they also made these datasets available to the community (with permission of the original sources). While FPC represents a great step forward, it soon became clear that its throughput was too slow for the emerging 10 gigabits per second networks. Hence, no speedup can be gained by including this algorithm in an MPI library. They therefore changed the aim of the second half of the project. Instead of implementing FPC in an MPI library, they refocused their efforts to develop a parallel compression algorithm to further boost the throughput. After all, all modern high-end microprocessors contain multiple CPUs on a

  11. Development of whole core thermal-hydraulic analysis program ACT. 4. Simplified fuel assembly model and parallelization by MPI

    International Nuclear Information System (INIS)

    Ohshima, Hiroyuki

    2001-10-01

    A whole core thermal-hydraulic analysis program ACT is being developed for the purpose of evaluating detailed in-core thermal hydraulic phenomena of fast reactors including the effect of the flow between wrapper-tube walls (inter-wrapper flow) under various reactor operation conditions. As appropriate boundary conditions in addition to a detailed modeling of the core are essential for accurate simulations of in-core thermal hydraulics, ACT consists of not only fuel assembly and inter-wrapper flow analysis modules but also a heat transport system analysis module that gives response of the plant dynamics to the core model. This report describes incorporation of a simplified model to the fuel assembly analysis module and program parallelization by a message passing method toward large-scale simulations. ACT has a fuel assembly analysis module which can simulate a whole fuel pin bundle in each fuel assembly of the core and, however, it may take much CPU time for a large-scale core simulation. Therefore, a simplified fuel assembly model that is thermal-hydraulically equivalent to the detailed one has been incorporated in order to save the simulation time and resources. This simplified model is applied to several parts of fuel assemblies in a core where the detailed simulation results are not required. With regard to the program parallelization, the calculation load and the data flow of ACT were analyzed and the optimum parallelization has been done including the improvement of the numerical simulation algorithm of ACT. Message Passing Interface (MPI) is applied to data communication between processes and synchronization in parallel calculations. Parallelized ACT was verified through a comparison simulation with the original one. In addition to the above works, input manuals of the core analysis module and the heat transport system analysis module have been prepared. (author)

  12. Representation of riverine DOC within a GCM: First framework for coupling soil carbon and lateral hydrology in MPI-ESM

    Science.gov (United States)

    Brovkin, V.; Gehlot, S.; Hagemann, S.

    2017-12-01

    The current state of the art General Circulation Models (GCMs) do not consider the lateral transport of dissolved organic carbon (DOC) from land to ocean via rivers/streams and the global carbon budget is primarily evaluated based only on vertical gas exchange processes between land or ocean carbon reservoirs. In high latitudes, the permafrost plays an important role in contributing to riverine organic carbon. Moreover, the vertical gas exchange processes are active during the lateral riverine carbon transport but are not considered in the impact of thawing permafrost on global climate. The interplay between permafrost and lateral hydrology is a substantial factor impacting the organic carbon inflow to the Arctic and its associated atmospheric exchange. In this research, we propose a framework of coupling the soil carbon transport via rivers using the hydrological discharge scheme (HD-Model) of MPI-ESM (Max-Planck Institute for Meteorology Earth System Model). The soil carbon classification is based on the solubility (YASSO soil carbon pools) and their subsequent attribution to the dissolved organic carbon via runoff (fast carbon pool) and baseflow (slow carbon pool). The HD-model, which simulates the river discharge for all land areas at a resolution of 0.5 degree, will be modified with inclusion of the DOC as tracer over test areas. Evaluation of DOC transport scheme is intended at reservoir level via available site measurements. The analysis will include global river networks for organic carbon transport with focus on permafrost and high latitude areas. Decomposition of DOC en-route land to ocean via vertical gas exchange processes will be included.

  13. Evaluation of Oceanic Surface Observation for Reproducing the Upper Ocean Structure in ECHAM5/MPI-OM

    Science.gov (United States)

    Luo, Hao; Zheng, Fei; Zhu, Jiang

    2017-12-01

    Better constraints of initial conditions from data assimilation are necessary for climate simulations and predictions, and they are particularly important for the ocean due to its long climate memory; as such, ocean data assimilation (ODA) is regarded as an effective tool for seasonal to decadal predictions. In this work, an ODA system is established for a coupled climate model (ECHAM5/MPI-OM), which can assimilate all available oceanic observations using an ensemble optimal interpolation approach. To validate and isolate the performance of different surface observations in reproducing air-sea climate variations in the model, a set of observing system simulation experiments (OSSEs) was performed over 150 model years. Generally, assimilating sea surface temperature, sea surface salinity, and sea surface height (SSH) can reasonably reproduce the climate variability and vertical structure of the upper ocean, and assimilating SSH achieves the best results compared to the true states. For the El Niño-Southern Oscillation (ENSO), assimilating different surface observations captures true aspects of ENSO well, but assimilating SSH can further enhance the accuracy of ENSO-related feedback processes in the coupled model, leading to a more reasonable ENSO evolution and air-sea interaction over the tropical Pacific. For ocean heat content, there are still limitations in reproducing the long time-scale variability in the North Atlantic, even if SSH has been taken into consideration. These results demonstrate the effectiveness of assimilating surface observations in capturing the interannual signal and, to some extent, the decadal signal but still highlight the necessity of assimilating profile data to reproduce specific decadal variability.

  14. Time dependency of the prediction skill for the North Atlantic subpolar gyre in initialized decadal hindcasts with MPI-ESM

    Science.gov (United States)

    Brune, Sebastian; Düsterhus, Andre; Pohlmann, Holger; Müller, Wolfgang; Baehr, Johanna

    2017-04-01

    We analyze the time dependency of decadal hindcast skill in the North Atlantic subpolar gyre within the time period 1961-2013. We compare anomaly correlation coefficients and interquartile ranges of total upper ocean heat content and sea surface temperature for three differently initialized sets of hindcast simulations with the global coupled model MPI-ESM. All initializations use weakly coupled assimilation with the same full-field nudging in the atmospheric component and different assimilation techniques for oceanic temperature and salinity: (1) ensemble Kalman filter assimilating EN4 and HadISST observations, (2) nudging of anomalies to ORAS4 reanalysis, (3) nudging of full values to ORAS4 reanalysis. We find that hindcast skill depends strongly on the evaluation time period, with higher hindcast skill during strong multiyear trends and lower hindcast skill in the absence of such trends. While there may only be small differences between the prediction systems in the analysis focusing on the entire hindcast period, these differences between the hindcast systems are much more pronounced when investigating any 20-year subperiod within the entire hindcast period. For the ensemble Kalman filter high skill in the assimilation experiment is generally linked to high skill in the initialized hindcasts. Such direct link does not seem to exist in the hindcasts initialized by either nudged system. In the ensemble Kalman filter initialized hindcasts, we find significant hindcast skill for up to 5 to 8 lead years, except for the 1970s. In the nudged system initialized hindcasts, hindcast skill is consistently diminished in lead years 2 and 3 with lowest skill in the 1970s as well. Overall, we find that a model-consistent assimilation technique can improve hindcast skill. Further, the evaluation of 20 year subperiods within the full hindcast period provides essential insights to judge the success of both the assimilation and the subsequent hindcast skill.

  15. Implementing the PM Programming Language using MPI and OpenMP - a New Tool for Programming Geophysical Models on Parallel Systems

    Science.gov (United States)

    Bellerby, Tim

    2015-04-01

    PM (Parallel Models) is a new parallel programming language specifically designed for writing environmental and geophysical models. The language is intended to enable implementers to concentrate on the science behind the model rather than the details of running on parallel hardware. At the same time PM leaves the programmer in control - all parallelisation is explicit and the parallel structure of any given program may be deduced directly from the code. This paper describes a PM implementation based on the Message Passing Interface (MPI) and Open Multi-Processing (OpenMP) standards, looking at issues involved with translating the PM parallelisation model to MPI/OpenMP protocols and considering performance in terms of the competing factors of finer-grained parallelisation and increased communication overhead. In order to maximise portability, the implementation stays within the MPI 1.3 standard as much as possible, with MPI-2 MPI-IO file handling the only significant exception. Moreover, it does not assume a thread-safe implementation of MPI. PM adopts a two-tier abstract representation of parallel hardware. A PM processor is a conceptual unit capable of efficiently executing a set of language tasks, with a complete parallel system consisting of an abstract N-dimensional array of such processors. PM processors may map to single cores executing tasks using cooperative multi-tasking, to multiple cores or even to separate processing nodes, efficiently sharing tasks using algorithms such as work stealing. While tasks may move between hardware elements within a PM processor, they may not move between processors without specific programmer intervention. Tasks are assigned to processors using a nested parallelism approach, building on ideas from Reyes et al. (2009). The main program owns all available processors. When the program enters a parallel statement then either processors are divided out among the newly generated tasks (number of new tasks number of processors

  16. Numerical Modeling of 3D Seismic Wave Propagation around Yogyakarta, the Southern Part of Central Java, Indonesia, Using Spectral-Element Method on MPI-GPU Cluster

    Science.gov (United States)

    Sudarmaji; Rudianto, Indra; Eka Nurcahya, Budi

    2018-04-01

    A strong tectonic earthquake with a magnitude of 5.9 Richter scale has been occurred in Yogyakarta and Central Java on May 26, 2006. The earthquake has caused severe damage in Yogyakarta and the southern part of Central Java, Indonesia. The understanding of seismic response of earthquake among ground shaking and the level of building damage is important. We present numerical modeling of 3D seismic wave propagation around Yogyakarta and the southern part of Central Java using spectral-element method on MPI-GPU (Graphics Processing Unit) computer cluster to observe its seismic response due to the earthquake. The homogeneous 3D realistic model is generated with detailed topography surface. The influences of free surface topography and layer discontinuity of the 3D model among the seismic response are observed. The seismic wave field is discretized using spectral-element method. The spectral-element method is solved on a mesh of hexahedral elements that is adapted to the free surface topography and the internal discontinuity of the model. To increase the data processing capabilities, the simulation is performed on a GPU cluster with implementation of MPI (Message Passing Interface).

  17. Characterization of Sendai virus persistently infected L929 cells and Sendai virus pi strain: recombinant Sendai viruses having Mpi protein shows lower cytotoxicity and are incapable of establishing persistent infection

    International Nuclear Information System (INIS)

    Nishio, Machiko; Tsurudome, Masato; Ito, Morihiro; Kawano, Mitsuo; Komada, Hiroshi; Ito, Yasuhiko

    2003-01-01

    It is commonly accepted that the temperature-sensitive phenotype of Sendai virus (SeV) persistently infected cells is caused by the M and/or HN proteins. Expression level of the L, M, HN, and V proteins is extremely low in L929 cells persistently infected with SeVpi (L929/SeVpi cells) incubated at 38 deg. C. The HN protein quickly disappears in L929/SeVpi cells following a temperature shift up to 38 deg. C, and pulse-chase experiments show that the Lpi, HNpi, and Mpi proteins are unstable at 38 deg. C. Following a temperature shift either upward or downward, M protein is translocated into the nucleus and then localizes to the perinuclear region. None of virus-specific polypeptides are detected in the cells primarily infected with SeVpi and incubated at 38 deg. C and virus proteins are not pulse-labeled at 38 deg. C, indicating that temperature-sensitive step is at an early stage of infection. The Mpi protein is transiently located in the nucleus of the SeVpi primarily infected cells. Recombinant SeVs possessing the HNpi or/and Mpi proteins are not temperature-sensitive. The HN protein is expressed at very low levels and the F protein localizes to the perinuclear region in rSeV(Mpi)-infected cells incubated at 38 deg. C for 18 h. rSeVs having the Mpi protein exhibit lower cytotoxicity and are incapable of establishing persistent infection. Amino acid 116 of the Mpi protein is related to the nuclear translocation and lower cytopathogenesis, whereas aa183 is involved in the interaction between M protein and viral glycoproteins

  18. Study of MPI based on parallel MOM on PC clusters for EM-beam scattering by 2-D PEC rough surfaces

    International Nuclear Information System (INIS)

    Jun, Ma; Li-Xin, Guo; An-Qi, Wang

    2009-01-01

    This paper firstly applies the finite impulse response filter (FIR) theory combined with the fast Fourier transform (FFT) method to generate two-dimensional Gaussian rough surface. Using the electric field integral equation (EFIE), it introduces the method of moment (MOM) with RWG vector basis function and Galerkin's method to investigate the electromagnetic beam scattering by a two-dimensional PEC Gaussian rough surface on personal computer (PC) clusters. The details of the parallel conjugate gradient method (CGM) for solving the matrix equation are also presented and the numerical simulations are obtained through the message passing interface (MPI) platform on the PC clusters. It finds significantly that the parallel MOM supplies a novel technique for solving a two-dimensional rough surface electromagnetic-scattering problem. The influences of the root-mean-square height, the correlation length and the polarization on the beam scattering characteristics by two-dimensional PEC Gaussian rough surfaces are finally discussed. (classical areas of phenomenology)

  19. TESLA GPUs versus MPI with OpenMP for the Forward Modeling of Gravity and Gravity Gradient of Large Prisms Ensemble

    Directory of Open Access Journals (Sweden)

    Carlos Couder-Castañeda

    2013-01-01

    Full Text Available An implementation with the CUDA technology in a single and in several graphics processing units (GPUs is presented for the calculation of the forward modeling of gravitational fields from a tridimensional volumetric ensemble composed by unitary prisms of constant density. We compared the performance results obtained with the GPUs against a previous version coded in OpenMP with MPI, and we analyzed the results on both platforms. Today, the use of GPUs represents a breakthrough in parallel computing, which has led to the development of several applications with various applications. Nevertheless, in some applications the decomposition of the tasks is not trivial, as can be appreciated in this paper. Unlike a trivial decomposition of the domain, we proposed to decompose the problem by sets of prisms and use different memory spaces per processing CUDA core, avoiding the performance decay as a result of the constant calls to kernels functions which would be needed in a parallelization by observations points. The design and implementation created are the main contributions of this work, because the parallelization scheme implemented is not trivial. The performance results obtained are comparable to those of a small processing cluster.

  20. Influence of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage.

    Science.gov (United States)

    Baker, Joseph L; Furbish, Jeffrey; Lindberg, Gerrick E

    2015-11-01

    We examine the effect of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage and contrast these results with the behavior of Trp-cage in water. We find the ionic liquid has a dramatic effect on Trp-cage, though many similarities with aqueous Trp-cage are observed. We assess Trp-cage folding by monitoring root mean square deviation from the crystallographic structure, radius of gyration, proline cis/trans isomerization state, protein secondary structure, amino acid contact formation and distance, and native and non-native contact formation. Starting from an unfolded configuration, Trp-cage folds in water at 298 K in less than 500 ns of simulation, but has very little mobility in the ionic liquid at the same temperature, which can be ascribed to the higher ionic liquid viscosity. At 365 K, the mobility of the ionic liquid is increased and initial stages of Trp-cage folding are observed, however Trp-cage does not reach the native folded state in 2 μs of simulation in the ionic liquid. Therefore, in addition to conventional molecular dynamics, we also employ scaled molecular dynamics to expedite sampling, and we demonstrate that Trp-cage in the ionic liquid does closely approach the aqueous folded state. Interestingly, while the reduced mobility of the ionic liquid is found to restrict Trp-cage motion, the ionic liquid does facilitate proline cis/trans isomerization events that are not seen in our aqueous simulations. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Predictability over the North Atlantic ocean in hindcast ensembles of MPI-ESM initialized by EnKF and three nudging systems

    Science.gov (United States)

    Brune, Sebastian; Pohlmann, Holger; Düsterhus, Andre; Kröger, Jürgen; Müller, Wolfgang; Baehr, Johanna

    2016-04-01

    We investigate hindcast skill for surface air temperature and upper ocean heat content (0-700m) in the North Atlantic for yearly mean values from 1960 to 2014 in four prediction systems based on the global coupled Max Planck Institute for Meteorology Earth System Model (MPI-ESM). We find that in the North Atlantic and within the four prediction systems under consideration only the EnKF initialized hindcasts reproduce the variability of the reference data well both in terms of anomaly correlation and representation of the probability density function. The systems under consideration only differ in the method how they incorporate surface and sub-surface oceanic temperatures and salinities during assimilation: ensemble Kalman Filter (EnKF), anomaly nudging of ORA reanalysis (BS-1), full field nudging of ORA and GECCO reanalysis, respectively (PT-ORA, PT-GEC). We assess the hindcast skill of each prediction system with reference to HadCRUT4 near surface air temperature data (Morice et al. 2012) and NOAA OC5 upper ocean heat content data (Levitus et al. 2012) using anomaly correlation (ACC) and by analysing the interquartile range (IQR) of the probability density function (PDF). Firstly, we calculate hindcast skill in terms of ACC and IQR against reference data over the whole time period. Here, the hindcast skills of EnKF and BS-1 are better for both ACC and IQR in lead years 2 to 5 when compared to PT-ORA and PT-GEC, their hindcast skill drops off after lead year 1. Secondly, the PDF of the reference data is not uniformly distributed over time. We therefore calculate ACC and IQR for a 20 year moving window. We find hindcast skill in terms of ACC for EnKF and BS-1 in the 1960s and from the 1990s onwards, up to eight lead years in advance, with almost no skill for the time period inbetween. In contrast, there is no skill for PT-ORA and PT-GEC in any period after lead year one. The IQR of reference data is best captured by the EnKF, in the 1960s and 1990s up to lead year

  2. FY 1999 cold demonstration of the Multi-Point Injection (MPI) process for stabilizing contaminated sludge in buried horizontal tanks with limited access at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kauschinger, J.L.; Lewis, B.E.; Spence, R.D.

    2000-01-01

    A major problem faced by the U.S. Department of Energy is the remediation of buried tank waste. Exhumation of the sludge is currently the preferred remediation method. However, exhumation does not typically remove all the contaminated material from the tank. The best management practices for in-tank treatment of wastes require an integrated approach to develop appropriate treatment agents that can be safely delivered and uniformly mixed with the sludge. Ground Environmental Services, Inc., has developed and demonstrated a remotely controlled, high-velocity, jet-delivery system, which is termed Multi-Point-Injection (MPItrademark). This robust jet-delivery system has been used to create homogeneous monoliths containing shallow-buried miscellaneous waste in trenches [fiscal year (FY) 1995] and surrogate sludge in a cylindrical test tank (FY 1998). During the FY 1998 demonstration, the MPI process was able to successfully form a 32-ton uniform monolith in about 8 min. Analytical data indicated that 10 tons of a zeolite-type physical surrogate were uniformly mixed within the 40-inch-thick monolith without lifting the MPI jetting tools off the tank floor. Over 1,000 lb of cohesive surrogates, with consistencies of Gunite and Associated Tanks (GAATs) TH-4 and Hanford tank sludges, were easily mixed into the monolith without exceeding a core temperature of 100 F during curing

  3. A comparison of observed extreme water levels at the German Bight elaborated through an extreme value analysis (EVA) with extremes derived from a regionally coupled ocean-atmospheric climate model (MPI-OM)

    Science.gov (United States)

    Möller, Jens; Heinrich, Hartmut

    2017-04-01

    As a consequence of climate change atmospheric and oceanographic extremes and their potential impacts on coastal regions are of growing concern for governmental authorities responsible for the transportation infrastructure. Highest risks for shipping as well as for rail and road traffic originate from combined effects of extremes of storm surges and heavy rainfall which sometimes lead to insufficient dewatering of inland waterways. The German Ministry of Transport and digital Infrastructure therefore has tasked its Network of Experts to investigate the possible evolutions of extreme threats for low lands and especially for Kiel Canal, which is an important shortcut for shipping between the North and Baltic Seas. In this study we present results of a comparison of an Extreme Value Analysis (EVA) carried out on gauge observations and values derived from a coupled Regional Ocean-Atmosphere Climate Model (MPI-OM). High water levels at the coasts of the North and Baltic Seas are one of the most important hazards which increase the risk of flooding of the low-lying land and prevents such areas from an adequate dewatering. In this study changes in the intensity (magnitude of the extremes) and duration of extreme water levels (above a selected threshold) are investigated for several gauge stations with data partly reaching back to 1843. Different methods are used for the extreme value statistics, (1) a stationary general Pareto distribution (GPD) model as well as (2) an instationary statistical model for better reproduction of the impact of climate change. Most gauge stations show an increase of the mean water level of about 1-2 mm/year, with a stronger increase of the highest water levels and a decrease (or lower increase) of the lowest water levels. Also, the duration of possible dewatering time intervals for the Kiel-Canal was analysed. The results for the historical gauge station observations are compared to the statistics of modelled water levels from the coupled

  4. MPI Enhancements in John the Ripper

    International Nuclear Information System (INIS)

    Sykes, Edward R; Lin, Michael; Skoczen, Wesley

    2010-01-01

    John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault-tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.

  5. MPI Enhancements in John the Ripper

    Science.gov (United States)

    Sykes, Edward R.; Lin, Michael; Skoczen, Wesley

    2010-11-01

    John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault-tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.

  6. Holocene climate change in North Africa and the end of the African humid period - results of new high-resolution transient simulations with the MPI-ESM 1.3

    Science.gov (United States)

    Dallmeyer, Anne; Claussen, Martin; Lorenz, Stephan

    2017-04-01

    The Max-Planck-Institute for Meteorology has recently undertaken high-resolution transient Holocene simulations using the fully-coupled Earth System Model MPI-ESM 1.3. The simulations cover the last 8000 years and are forced not only by reconstructed Holocene orbital variations and atmospheric greenhouse gas concentrations, but also by recent compilations of Holocene volcanic aerosol distributions, variations in spectral solar irradiance, stratospheric ozone and land-use change. The simulations reveal the ubiquitous "Holocene conundrum": simulated global mean temperatures increase during the mid-Holocene and stay constant during the late Holocene. Simulated mid-Holocene near-surface temperatures are too cold in large parts of the world. Simulated precipitation, however, agrees much better with reconstruction than temperatures do. Likewise simulated global biome pattern fit reconstructions nicely, except for North Western America. First results of these simulations are presented with the main focus on the North African monsoon region. The amplitude of the mid-Holocene African Humid Period (AHP) is well captured in terms of precipitation and vegetation cover, so is the south-ward transgression of the termination of the AHP seen in reconstructions. The Holocene weakening and southward retreat of the North African monsoon as well as changes in the monsoon dynamic including shifts in the seasonal cycle and their relation to the locally varying termination of the AHP are discussed in detail. Members of the Hamburg Holocene Team: Jürgen Bader (1), Sebastian Bathiany (2), Victor Brovkin (1), Martin Claussen (1,3), Traute Crüger (1), Roberta D'agostino (1), Anne Dallmeyer (1), Sabine Egerer (1), Vivienne Groner (1), Matthias Heinze (1), Tatiana Ilyina (1), Johann Jungclaus (1), Thomas Kleinen (1), Alexander Lemburg (1), Stephan Lorenz (1), Thomas Raddatz (1), Hauke Schmidt (1), Gerhard Schmiedl (3), Bjorn Stevens (1), Claudia Timmreck (1), Matthew Toohey (4) (1) Max

  7. ACCF/ASNC appropriateness criteria for single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI): a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group and the American Society of Nuclear Cardiology endorsed by the American Heart Association.

    Science.gov (United States)

    Brindis, Ralph G; Douglas, Pamela S; Hendel, Robert C; Peterson, Eric D; Wolk, Michael J; Allen, Joseph M; Patel, Manesh R; Raskin, Ira E; Hendel, Robert C; Bateman, Timothy M; Cerqueira, Manuel D; Gibbons, Raymond J; Gillam, Linda D; Gillespie, John A; Hendel, Robert C; Iskandrian, Ami E; Jerome, Scott D; Krumholz, Harlan M; Messer, Joseph V; Spertus, John A; Stowers, Stephen A

    2005-10-18

    Under the auspices of the American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC), an appropriateness review was conducted for radionuclide cardiovascular imaging (RNI), specifically gated single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). The review assessed the risks and benefits of the imaging test for several indications or clinical scenarios and scored them based on a scale of 1 to 9, where the upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The mid range (4 to 6) implies that the test may be generally acceptable and may be a reasonable approach for the indication. The indications for this review were primarily drawn from existing clinical practice guidelines and modified based on discussion by the ACCF Appropriateness Criteria Working Group and the Technical Panel members who rated the indications. The method for this review was based on the RAND/UCLA approach for evaluating appropriateness, which blends scientific evidence and practice experience. A modified Delphi technique was used to obtain first- and second-round ratings of 52 clinical indications. The ratings were done by a Technical Panel with diverse membership, including nuclear cardiologists, referring physicians (including an echocardiographer), health services researchers, and a payer (chief medical officer). These results are expected to have a significant impact on physician decision making and performance, reimbursement policy, and future research directions. Periodic assessment and updating of criteria will be undertaken as needed.

  8. Description of the double Compton spectrometer at Mayence MPI

    International Nuclear Information System (INIS)

    Borchert, H.; Ziegler, B.; Gimm, H.; Zieger, A.; Hughes, R.J.; Ahrens, J.

    1977-01-01

    The double Compton spectrometer of the Laboratories of the Mayence Linear Accelerator consists in two identical magnetic spectrometers, in which the electron scattered forwards by photons through a Compton process, are detected. The spectrometers have been built to detect 10-350 MeV photons and, as they involve thin Compton targets, their effect on the photon flux is negligible. They are put in cascade inside a well collimated bremsstrahlung beam. A thick absorbing target (max. thickness 2m) can be inserted inside the beam. The facility is outlined, some special properties of the accelerator and the bremsstrahlung beam are given. The properties of a Compton spectrometer involving eleven detectors are given by eleven response functions giving the relations between the photon flux impinging the Compton target and the counting rates of the detectors for a given adjustment of the magnets. A Monte-Carlo method is used for the calculation together with analytical methods neglecting the multiple scattering effects [fr

  9. Recent results from the CERN-MPI spectrometer

    International Nuclear Information System (INIS)

    Hyams, B.

    1975-01-01

    Results are presented from preliminary data on missing mass and polarization in π - p → nπ + π - reactions off a transversely polarized target and π - p → nK + K - reactions at 18.4 GeV/c establishing a spin 4 + resonance, for which quantum numbers are found

  10. MPI and GPU parallelization of novel SD algorithms

    Indian Academy of Sciences (India)

    component of molecular dynamics is the use of well-suited atomistic and .... that the limiting case f = 1 completely removes the ..... from Stanford University, that Gromacs interfaces in ... NVIDIA GEForce 9600 GT graphical card with 512 Mb.

  11. Numerical discrepancy between serial and MPI parallel computations

    Directory of Open Access Journals (Sweden)

    Sang Bong Lee

    2016-09-01

    Full Text Available Numerical simulations of 1D Burgers equation and 2D sloshing problem were carried out to study numerical discrepancy between serial and parallel computations. The numerical domain was decomposed into 2 and 4 subdomains for parallel computations with message passing interface. The numerical solution of Burgers equation disclosed that fully explicit boundary conditions used on subdomains of parallel computation was responsible for the numerical discrepancy of transient solution between serial and parallel computations. Two dimensional sloshing problems in a rectangular domain were solved using OpenFOAM. After a lapse of initial transient time sloshing patterns of water were significantly different in serial and parallel computations although the same numerical conditions were given. Based on the histograms of pressure measured at two points near the wall the statistical characteristics of numerical solution was not affected by the number of subdomains as much as the transient solution was dependent on the number of subdomains.

  12. MPI fuer Physik und Astrophysik. Werner-Heisenberg-Institut fuer Physik - annual report 1983

    International Nuclear Information System (INIS)

    1983-12-01

    This annual report contains short description of the work performed at the named institute together with a list of publications and speeches. The work concerns experiments at CERN and at the storage rings PETRA and CESR, theoretical work on unified field theories and supersymmetry, as well as developments of the ALEPH detector for the LEP storage ring. (HSI) [de

  13. 32 CFR 637.2 - Use of MPI and DAC Detectives/Investigators.

    Science.gov (United States)

    2010-07-01

    ... employed in the following investigations: (a) Offenses for which the maximum punishment listed in the Table of Maximum Punishment, Manual for Courts-Martial, United States, 2002 is confinement for 1 year or less. Provisions of the Federal Assimilative Crimes Act will also be considered when assigning cases to...

  14. Laser spectroscopy with a cooler ring at the ESR (GSI) and the TSR (MPI Heidelberg)

    International Nuclear Information System (INIS)

    Kuehl, T.; Borneis, S.; Greten, G.; Marx, D.; Neumann, R.; Schroeder, S.; Grieser, R.; Hoog, I.; Huber, G.; Klaft, I.; Klein, R.; Merz, P.; Balykin, V.; Bock, M.; Ellert, C.; Forck, P.; Grieser, M.; Grimm, R.; Habs, D.; Miesner, H.J.; Petrich, W.; Wanner, B.; Becker, C.; Schwalm, D.; Wolf, A.

    1992-01-01

    At the TSR cooler ring at Heidelberg, laser studies were carried out using singly charged lithium and beryllium ions. Laser spectroscopy of relativistic lithium ions (υ = 0.04c) yielded signals with a narrow linewidth, suitable for an experimental test of special relativity. A dramatic reduction of the beam temperature, as defined by the longitudinal velocity spread, was achieved via laser cooling in both cases. At the ion energies available at ESR it will become possible to prepare and store bare ions up to U 92+ . Electron cooling was successfully demonstrated for hydrogen-like Bi 82+ ions, where a laser experiment is scheduled to study the ground-state hyperfine splitting. (orig.)

  15. Photos from MPI: Module installation at CERN for 1999 Test Beam

    CERN Multimedia

    1999-01-01

    Photo1 - Three HEC-1 modules after mating in the clean room. Photo2 - Close-up of three HEC-1 modules in the clean room when mounting the PSB boards. Photo3 - Three HEC-2 modules being inserted into the test-beam cryostat. Photo4 - Three HEC-2 modules in the test-beam cryostat. Photo5 - Three HEC-1 and three HEC-2 modules in the test-beam cryostat. Photo6 - Three HEC-1 and three HEC-2 modules in the test-beam cryostat.

  16. Visit to the Russian Production and Assembly Sites in March 2000 (photos obtained from MPI)

    CERN Multimedia

    2000-01-01

    Photo1 - EST electrode production at LPI. Photo2 - EST electrode production at LPI. Photo3 - EST electrode production at LPI. Photo4 - Cold test of EST electrodes at LPI. Photo5 - Cold test of EST electrodes at LPI. Photo6 - The device for cleaning honeycomb mats at JINR. Photo7 - Module assembly at IHEP. Photo8 - Module assembly at IHEP. Photo9 - Module assembly at IHEP. Photo10 - Transport cases for "Molniya" modules (former bomb cases)

  17. Focusing effects of a laser beam in the non resonant MPI of gases

    International Nuclear Information System (INIS)

    Baravian, G.; Sultan, G.

    1984-09-01

    The authors give a method to interpret correctly the multiphoton ionization in the case of no resonance and saturation. The calculation model is applied to hydrogen to calculate the ion production related to the intensity of laser pulse. Different applications and methods are given. The six-photon ionization cross-section of the krypton is calculated [fr

  18. A parallel algorithm for Hamiltonian matrix construction in electron-molecule collision calculations: MPI-SCATCI

    Science.gov (United States)

    Al-Refaie, Ahmed F.; Tennyson, Jonathan

    2017-12-01

    Construction and diagonalization of the Hamiltonian matrix is the rate-limiting step in most low-energy electron - molecule collision calculations. Tennyson (1996) implemented a novel algorithm for Hamiltonian construction which took advantage of the structure of the wavefunction in such calculations. This algorithm is re-engineered to make use of modern computer architectures and the use of appropriate diagonalizers is considered. Test calculations demonstrate that significant speed-ups can be gained using multiple CPUs. This opens the way to calculations which consider higher collision energies, larger molecules and / or more target states. The methodology, which is implemented as part of the UK molecular R-matrix codes (UKRMol and UKRMol+) can also be used for studies of bound molecular Rydberg states, photoionization and positron-molecule collisions.

  19. Design and implementation of a hybrid MPI-CUDA model for the Smith-Waterman algorithm.

    Science.gov (United States)

    Khaled, Heba; Faheem, Hossam El Deen Mostafa; El Gohary, Rania

    2015-01-01

    This paper provides a novel hybrid model for solving the multiple pair-wise sequence alignment problem combining message passing interface and CUDA, the parallel computing platform and programming model invented by NVIDIA. The proposed model targets homogeneous cluster nodes equipped with similar Graphical Processing Unit (GPU) cards. The model consists of the Master Node Dispatcher (MND) and the Worker GPU Nodes (WGN). The MND distributes the workload among the cluster working nodes and then aggregates the results. The WGN performs the multiple pair-wise sequence alignments using the Smith-Waterman algorithm. We also propose a modified implementation to the Smith-Waterman algorithm based on computing the alignment matrices row-wise. The experimental results demonstrate a considerable reduction in the running time by increasing the number of the working GPU nodes. The proposed model achieved a performance of about 12 Giga cell updates per second when we tested against the SWISS-PROT protein knowledge base running on four nodes.

  20. Real-time monitoring of BTEX in air via ambient-pressure MPI

    Science.gov (United States)

    Swenson, Orven F.; Carriere, Josef P.; Isensee, Harlan; Gillispie, Gregory D.; Cooper, William F.; Dvorak, Michael A.

    1998-05-01

    We have developed and begun to field test a very sensitive method for real-time measurements of single-ring aromatic hydrocarbons in ambient air. In this study, we focus on the efficient 1 + 1 resonance enhanced multiphoton ionization (REMPI) of the BTEX species in the narrow region between 266 and 267 nm. We particularly emphasize 266.7 nm, a wavelength at which both benzene and toluene exhibit a sharp absorbance feature and benzene and its alkylated derivatives all absorb. An optical parametric oscillator system generating 266.7 nm, a REMPI cell, and digital oscilloscope detector are mounted on a breadboard attached to a small cart. In the first field test, the cart was wheeled through the various rooms of a chemistry research complex. Leakage of fuel through the gas caps of cars and light trucks in a parking lot was the subject of the second field test. The same apparatus was also used for a study in which the performance of the REMPI detector and a conventional photoionization detector were compared as a BTEX mixture was eluted by gas chromatography. Among the potential applications of the methodology are on-site analysis of combustion and manufacturing processes, soil gas and water headspace monitoring, space cabin and building air quality, and fuel leak detection.

  1. Impacts of deforestation and afforestation in the Mediterranean region as simulated by the MPI atmospheric GCM

    Science.gov (United States)

    Dümenil Gates, Lydia; Ließ, Stefan

    2001-10-01

    For two reasons it is important to study the sensitivity of the global climate to changes in the vegetation cover over land. First, in the real world, changes in the vegetation cover may have regional and global implications. Second, in numerical simulations, the sensitivity of the simulated climate may depend on the specific parameterization schemes employed in the model and on the model's large-scale systematic errors. The Max-Planck-Institute's global general circulation model ECHAM4 has been used to study the sensitivity of the local and global climate during a full annual cycle to deforestation and afforestation in the Mediterranean region. The deforestation represents an extreme desertification scenario for this region. The changes in the afforestation experiment are based on the pattern of the vegetation cover 2000 years before present when the climate in the Mediterranean was more humid. The comparison of the deforestation integration to the control shows a slight cooling at the surface and reduced precipitation during the summer as a result of less evapotranspiration of plants and less evaporation from the assumption of eroded soils. There is no significant signal during the winter season due to the stronger influence of the mid-latitude baroclinic disturbances. In general, the results of the afforestation experiment are opposite to those of the deforestation case. A significant response was found in the vicinity of grid points where the land surface characteristics were modified. The response in the Sahara in the afforestation experiment is in agreement with the results from other general circulation model studies.

  2. Comparing the OpenMP, MPI, and Hybrid Programming Paradigm on an SMP Cluster

    Science.gov (United States)

    Jost, Gabriele; Jin, Hao-Qiang; anMey, Dieter; Hatay, Ferhat F.

    2003-01-01

    Clusters of SMP (Symmetric Multi-Processors) nodes provide support for a wide range of parallel programming paradigms. The shared address space within each node is suitable for OpenMP parallelization. Message passing can be employed within and across the nodes of a cluster. Multiple levels of parallelism can be achieved by combining message passing and OpenMP parallelization. Which programming paradigm is the best will depend on the nature of the given problem, the hardware components of the cluster, the network, and the available software. In this study we compare the performance of different implementations of the same CFD benchmark application, using the same numerical algorithm but employing different programming paradigms.

  3. Simulating chemical systems : MPI and GPU parallelization of novel SD algorithms

    NARCIS (Netherlands)

    Goga, N.

    Molecular dynamics is used for simulating chemical systems with the goal of studying a large range of phenomena starting from cell structures to the design of new materials, drugs, etc. A very important component of molecular dynamics is the use of well-suited atomistic and molecular modelling of

  4. Characterization of nuclear fuel using immersion and method of penetration (MPI)

    International Nuclear Information System (INIS)

    Faeda, K. C. M.; Lameiras, F.S.; Ferraz, W.B.; Machado, G.C.

    2011-01-01

    The characterization of nuclear fuel is of great importance and aims to minimize the effects related to burning and the temperature in the fuel, so that the stability of the fuel during the time of his stay in the reactor core. The method of penetration and use the boost immersion with vacuum impregnation to measure density and open porosity of ceramic materials. It is non-destructive if the liquid impregnation can be removed from the sample. The impregnation requires the use of a liquid with low surface tension and small variation of surface tension with temperature. The xylene due its large industrial employment has been widely used for this purpose. However, it presents serious problems of toxicity. In this work, comparable studies of xylene with water + detergent to measure density and porosity in alumina pellets. The atmospheric pressure, temperature and humidity were monitored during the measurements and considered as covariates. (author)

  5. DAFS Storage for High Performance Computing Using MPI-I/O: Design and Experience

    National Research Council Canada - National Science Library

    Velusamy, Vijay

    2004-01-01

    .... DAFS is a well-defined highperformance protocol for file access across a network as well as set of APIs, uDAFS, for user level OS-bypassing application programming, designed to take advantage of RDMA-based transports, such as Virtual Interface Architecture (VIA), InfiniBand Architecture1, and iWARP.

  6. PENERAPAN TOTAL QUALITY MANAGEMENT PADA PROGRAM STUDI MPI FAKULTAS TARBIYAH DAN KEGURUAN UIN ALAUDDIN

    Directory of Open Access Journals (Sweden)

    Syahid Syahid

    2017-12-01

    Full Text Available The purpose of this paper is to describe (1 the concept of total quality mana-gement, (2 the theoretical foundation of total quality management, and (3 the application of total quality management in Education management study program at the Faculty of Education and Teaching Science, UIN Alauddin Ma-kassar. There are some theoretical bases to support the implementation of TQM in educational institutions. One is the theory of Deming which can be identified from (a Deming’s chain reaction model, (b Deming’s continuous improvement cycle, (c Deming’s theory of Variance, and (d Deming's fourteen points of management. The application of TQM in Management Studies Program Faculty of Tarbiyah and Teaching Education UIN Alauddin have not maximized. The data indicated that 70.19% respondents said that the implementation of TQM is at a mediocre level, 0.90% respondents said good, and 1.85% respondents said that the implementation of TQM has been very good.

  7. PENERAPAN TOTAL QUALITY MANAGEMENT PADA PROGRAM STUDI MPI FAKULTAS TARBIYAH DAN KEGURUAN UIN ALAUDDIN

    OpenAIRE

    Syahid Syahid

    2017-01-01

    The purpose of this paper is to describe (1) the concept of total quality mana-gement, (2) the theoretical foundation of total quality management, and (3) the application of total quality management in Education management study program at the Faculty of Education and Teaching Science, UIN Alauddin Ma-kassar. There are some theoretical bases to support the implementation of TQM in educational institutions. One is the theory of Deming which can be identified from (a) Deming’s chain reaction mo...

  8. Computational modeling of pitching cylinder-type ocean wave energy converters using 3D MPI-parallel simulations

    Science.gov (United States)

    Freniere, Cole; Pathak, Ashish; Raessi, Mehdi

    2016-11-01

    Ocean Wave Energy Converters (WECs) are devices that convert energy from ocean waves into electricity. To aid in the design of WECs, an advanced computational framework has been developed which has advantages over conventional methods. The computational framework simulates the performance of WECs in a virtual wave tank by solving the full Navier-Stokes equations in 3D, capturing the fluid-structure interaction, nonlinear and viscous effects. In this work, we present simulations of the performance of pitching cylinder-type WECs and compare against experimental data. WECs are simulated at both model and full scales. The results are used to determine the role of the Keulegan-Carpenter (KC) number. The KC number is representative of viscous drag behavior on a bluff body in an oscillating flow, and is considered an important indicator of the dynamics of a WEC. Studying the effects of the KC number is important for determining the validity of the Froude scaling and the inviscid potential flow theory, which are heavily relied on in the conventional approaches to modeling WECs. Support from the National Science Foundation is gratefully acknowledged.

  9. Mixed Precision Solver Scalable to 16000 MPI Processes for Lattice Quantum Chromodynamics Simulations on the Oakforest-PACS System

    OpenAIRE

    Boku, Taisuke; Ishikawa, Ken-Ichi; Kuramashi, Yoshinobu; Meadows, Lawrence

    2017-01-01

    Lattice Quantum Chromodynamics (Lattice QCD) is a quantum field theory on a finite discretized space-time box so as to numerically compute the dynamics of quarks and gluons to explore the nature of subatomic world. Solving the equation of motion of quarks (quark solver) is the most compute-intensive part of the lattice QCD simulations and is one of the legacy HPC applications. We have developed a mixed-precision quark solver for a large Intel Xeon Phi (KNL) system named "Oakforest-PACS", empl...

  10. Impact of melt ponds on Arctic sea ice in past and future climates as simulated by MPI-ESM

    Directory of Open Access Journals (Sweden)

    Erich Roeckner

    2012-09-01

    Full Text Available The impact of melt ponds on Arctic sea ice is estimated from model simulations of the historical and future climate. The simulations were performed with and without the effect of melt ponds on sea ice melt, respectively. In the last thirty years of the historical simulations, melt ponds develop predominantly in the continental shelf regions and in the Canadian archipelago. Accordingly, the ice albedo in these regions is systematically smaller than in the no-pond simulations, the sea ice melt is enhanced, and both the ice concentration and ice thickness during the September minimum are reduced. Open ponds decrease the ice albedo, resulting in enhanced ice melt, less sea ice and further pond growth. This positive feedback entails a more realistic representation of the seasonal cycle of Northern Hemisphere sea ice area. Under the premise that the observed decline of Arctic sea ice over the period of modern satellite observations is mainly externally driven and, therefore, potentially predictable, both model versions underestimate the decline in Arctic sea ice. This presupposition, however, is challenged by our model simulations which show a distinct modulation of the downward Arctic sea ice trends by multidecadal variability. At longer time scales, an impact of pond activation on Arctic sea ice trends is more evident: In the Representative Concentration Pathway scenario RCP45, the September sea ice is projected to vanish by the end of the 21st century. In the active-pond simulation, this happens up to two decades earlier than in the no-pond simulations.

  11. Cryogenic Concept for the Low-energy Electrostatic Cryogenic Storage Ring (CSR) at MPI-K in Heidelberg

    International Nuclear Information System (INIS)

    Hahn, R. von; Andrianarijaona, V.; Crespo Lopez-Urrutia, J. R.; Fadil, H.; Grieser, M.; Mallinger, V.; Orlov, D. A.; Schroeter, C. D.; Schwalm, D.; Ullrich, J.; Weber, T.; Wolf, A.; Haberstroh, Ch.; Quack, H.; Rappaport, M.; Zajfman, D.

    2006-01-01

    At the Max-Planck-Institut fuer Kernphysik in Heidelberg a next generation electrostatic storage ring for cryogenic temperatures is under development. The main focus of this unique machine is the research on ions, molecules and clusters up to bio molecules in the energy range of 20-300 keV at low temperatures down to 2 Kelvin. The achievement of this low temperature for all material walls seen by the ions in the storage ring will allow novel experiments to be performed, such as rotational and vibrational state control of molecular ions and their interaction with ultra-low energy electrons and laser radiation. The low temperature of the storage ring not only causes a strong reduction of black body radiation incident onto the stored particles, but also acts as a large cryopump, expected to lead to a vacuum in the 10-15 mbar range. In this paper the cryogenic concept of the storage ring and the related vacuum design will be presented

  12. ATOP - The Advanced Taiwan Ocean Prediction System Based on the mpiPOM. Part 1: Model Descriptions, Analyses and Results

    Directory of Open Access Journals (Sweden)

    Leo Oey

    2013-01-01

    Full Text Available A data-assimilated Taiwan Ocean Prediction (ATOP system is being developed at the National Central University, Taiwan. The model simulates sea-surface height, three-dimensional currents, temperature and salinity and turbulent mixing. The model has options for tracer and particle-tracking algorithms, as well as for wave-induced Stokes drift and wave-enhanced mixing and bottom drag. Two different forecast domains have been tested: a large-grid domain that encompasses the entire North Pacific Ocean at 0.1° × 0.1° horizontal resolution and 41 vertical sigma levels, and a smaller western North Pacific domain which at present also has the same horizontal resolution. In both domains, 25-year spin-up runs from 1988 - 2011 were first conducted, forced by six-hourly Cross-Calibrated Multi-Platform (CCMP and NCEP reanalysis Global Forecast System (GSF winds. The results are then used as initial conditions to conduct ocean analyses from January 2012 through February 2012, when updated hindcasts and real-time forecasts begin using the GFS winds. This paper describes the ATOP system and compares the forecast results against satellite altimetry data for assessing model skills. The model results are also shown to compare well with observations of (i the Kuroshio intrusion in the northern South China Sea, and (ii subtropical counter current. Review and comparison with other models in the literature of ¡§(i¡¨ are also given.

  13. Multi-GPU-based acceleration of the explicit time domain volume integral equation solver using MPI-OpenACC

    KAUST Repository

    Feki, Saber

    2013-07-01

    An explicit marching-on-in-time (MOT)-based time-domain volume integral equation (TDVIE) solver has recently been developed for characterizing transient electromagnetic wave interactions on arbitrarily shaped dielectric bodies (A. Al-Jarro et al., IEEE Trans. Antennas Propag., vol. 60, no. 11, 2012). The solver discretizes the spatio-temporal convolutions of the source fields with the background medium\\'s Green function using nodal discretization in space and linear interpolation in time. The Green tensor, which involves second order spatial and temporal derivatives, is computed using finite differences on the temporal and spatial grid. A predictor-corrector algorithm is used to maintain the stability of the MOT scheme. The simplicity of the discretization scheme permits the computation of the discretized spatio-temporal convolutions on the fly during time marching; no \\'interaction\\' matrices are pre-computed or stored resulting in a memory efficient scheme. As a result, most often the applicability of this solver to the characterization of wave interactions on electrically large structures is limited by the computation time but not the memory. © 2013 IEEE.

  14. Full-field initialized decadal predictions with the MPI earth system model: an initial shock in the North Atlantic

    Science.gov (United States)

    Kröger, Jürgen; Pohlmann, Holger; Sienz, Frank; Marotzke, Jochem; Baehr, Johanna; Köhl, Armin; Modali, Kameswarrao; Polkova, Iuliia; Stammer, Detlef; Vamborg, Freja S. E.; Müller, Wolfgang A.

    2017-12-01

    Our decadal climate prediction system, which is based on the Max-Planck-Institute Earth System Model, is initialized from a coupled assimilation run that utilizes nudging to selected state parameters from reanalyses. We apply full-field nudging in the atmosphere and either full-field or anomaly nudging in the ocean. Full fields from two different ocean reanalyses are considered. This comparison of initialization strategies focuses on the North Atlantic Subpolar Gyre (SPG) region, where the transition from anomaly to full-field nudging reveals large differences in prediction skill for sea surface temperature and ocean heat content (OHC). We show that nudging of temperature and salinity in the ocean modifies OHC and also induces changes in mass and heat transports associated with the ocean flow. In the SPG region, the assimilated OHC signal resembles well OHC from observations, regardless of using full fields or anomalies. The resulting ocean transport, on the other hand, reveals considerable differences between full-field and anomaly nudging. In all assimilation runs, ocean heat transport together with net heat exchange at the surface does not correspond to OHC tendencies, the SPG heat budget is not closed. Discrepancies in the budget in the cases of full-field nudging exceed those in the case of anomaly nudging by a factor of 2-3. The nudging-induced changes in ocean transport continue to be present in the free running hindcasts for up to 5 years, a clear expression of memory in our coupled system. In hindcast mode, on annual to inter-annual scales, ocean heat transport is the dominant driver of SPG OHC. Thus, we ascribe a significant reduction in OHC prediction skill when using full-field instead of anomaly initialization to an initialization shock resulting from the poor initialization of the ocean flow.

  15. GENETIC DI VERSITY OF A MPI CILLIN-RE SI STANT Vibri o ISOLATED FROM VAR IOUS STA GES OF TIGER SHRIMP LARVA E DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    WIDANARNI a

    2000-01-01

    Full Text Available This research was carri ed out to st udy genetic di versity of ampici llin-resi sta nt Vi brio from variou s stages o f t iger shrimp larvae (Penaeus Monodon de velopment from,Ta mbak Inti Raky at hatchery, near Labuan, West Jav a, Indonesia. A total of 25 am picillin- resistant Vi brio is ol at es were isolated using thiosul pha te citrat e bi le -sal t sucr os e agar ( TCBS -Aga r a nd s eawa ter complet e agar (SWC-Agar. Physiological and bioc he mical cha racteri zation showed that the i solates could be grouped into only two species, i.e. V. har veyi from the egg s tage; and V. metschnikovii from larvae and post-larval stage (i.e nauplius, zoe a, mysis, PLi, P L5, PL,0, and P L,5. Thes e is olates were also present i n t heir r espective rearing wate r of each s tage and som e natural feed. Schi zoty ping analysis e mployin g rest riction endonuclease Noll (5 '-GC4GGCCGC indicate d that the is ol at es could be grouped i nto at l east 13 differ en t ge no ty pe s. Therefore, schizoty ping was more di sc ri mi native than phy siologica l charac te riz ati on . This stud y showed that particu lar grou ps of Vi brio colonize d all s tages of shrimp la rvae and de monstrated cl os ed ph yl og en et ic r elationsh ip. These gro ups of Vi brio mi gh t be the do mi na nt microbiota whic h could suppress the de velopment of othe r Vi brio in cl ud ing th e pathogen ic Vi brio.

  16. Psycho-Motor and Error Enabled Simulations: Modeling Vulnerable Skills in the Pre Mastery Phase - Medical Practice Initiative Procedural Skill Decay and Maintenance (MPI-PSD)

    Science.gov (United States)

    2016-12-01

    B were set between 10% and 90% of the maximum closed loop force handled by the device (14.5 N/mm), or between 1.45 and 13.05 N/mm. The effective...include administration of vasoactive medications , rapid resuscitation, total parenteral nutrition, and delivery of caustic medications .2 When considering...Award Number: W81XWH-13-1-0080 TITLE: "Psycho-Motor and Error Enabled Simulations: Modeling Vulnerable Skills in the Pre-Mastery Phase - Medical

  17. Psycho-Motor and Error Enabled Simulations Modeling Vulnerable Skills in the Pre-Mastery Phase - Medical Practice Initiative Procedural Skill Decay and Maintenance (MPI-PSD)

    Science.gov (United States)

    2015-04-01

    not achieve significance for blocks 1-2 (mean: 1.8mm CI: -0.8, 4.4). Page 8 of 25 Figure 7: Controlling a haptic device, participants stretched a...Standardized locations for the consumables containers were also selected to be within the volume captured by motion sensors and adjacent to the catheter...Hernia Before After Page 14 of 25 Sensor -containing Lab Jackets. In pilot testing, it was identified that the attachment of motion capture sensors to

  18. Psycho-Motor and Error Enabled Simulations: Modeling Vulnerable Skills in the Pre-Mastery Phase Medical Practice Initiative Procedural Skill Decay and Maintenance (MPI-PSD)

    Science.gov (United States)

    2014-04-01

    Figure 7b. Participant performs the simulation while wearing motion- capture sensors The team traveled to Innovative Sports on 03/03/14 to view...team is now collaborating with Dr. Michael Zinn at the University of Wisconsin-Madison who is an expert in haptic and virtual reality systems. A...choice was made to purchase one Force Dimension Omega Series haptic device (Figure 6a) as well as two GeoMagic Touch devices (Figure 6b) that will

  19. [Testing the significance of psychic factors in the etiology of alopecia areata. II. Examination of personality by means of Eysenck's Personality Inventory (MPI) adapted by Choynowski].

    Science.gov (United States)

    Wygledowska-Kania, M; Bogdanowski, T

    1995-01-01

    We evaluated the role of psychic factors in the etiopathogenesis of alopecia areata on the basis of Eysenck's Personality Inventory adapted by Choynowski. 55 patients were tested (28 women and 27 men). The control group consisted of 50 volunteers. The analysis of the results showed that the neurotic type of personality was predominant in the group of patients (43.64%). Neurotic personality found in such a high percentage of the patients with alopecia areata may be an additional element in the group of psychic factors that possibly have some influence on the development of the disease.

  20. The Leishmania donovani complex: Genotypes of five metabolic enzymes (ICD, ME, MPI, G6PDH and FH), new targets for multilocus sequence typing

    Czech Academy of Sciences Publication Activity Database

    Zemanová, Eva; Jirků, Milan; Mauricio, I. L.; Horák, Aleš; Miles, M. A.; Lukeš, Julius

    2007-01-01

    Roč. 37, č. 2 (2007), s. 149-160 ISSN 0020-7519 R&D Projects: GA MŠk 2B06129 Grant - others:EU(EU) QLK2-CT-2001-01810 Institutional research plan: CEZ:AV0Z60220518 Source of funding: R - rámcový projekt EK Keywords : Leishmania donovani complex * zymodeme * multilocus sequence typing * Leishmania * phylogenetic network Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.392, year: 2007

  1. 7. Prevalence of CAD in asymptomatic type II diabetics, using MPI as screening tool. Single center cross sectional study from KSA

    Directory of Open Access Journals (Sweden)

    Anwar Jelani

    2017-10-01

    Conclusion: Despite higher rate of diabetes in Saudi Arabia, asymptomatic Diabetics have a lower than expected incidence of active CAD. There would be a need to test this notion further. This would require more studies to confirm our findings in Saudi population.

  2. The electrocatalytic activity of a supramolecular assembly of CoTsPc/FeT4MPyP on multi-walled carbon nanotubes towards L-glutathione, and its determination in human erythrocytes

    International Nuclear Information System (INIS)

    Luz, R.C.S.; Maroneze, C.M.; Tanaka, A.A.; Kubota, L.T.; Gushikem, Y.; Damos, F.S.

    2010-01-01

    The electrocatalytic activity of a supramolecular complex based on cobalt(II) phthalocyanine tetrasulfonate and iron(III) tetra-(N-methyl-4-pyridyl)-porphyrin adsorbed on multi-walled carbon nanotubes for the oxidation of L-glutathione (GSH) was investigated at pH 7.4. Scanning electron microscopy and energy dispersive X-ray spectrometry were used to characterize the morphologies and composition of the materials. The modified electrode displayed efficient electrocatalytic activity in terms of oxidation of GSH at an oxidation potential of 0 V (versus Ag/AgCl). Cyclic voltammetry and amperometry indicated that the oxidation involves 2-electrons, with a heterogeneous rate constant of 4.9 x 10 5 mol -1 L s -1 . The response is linear from 2 to 210 μmol L -1 , the sensitivity is 1570 μA L mmol -1 , the detection limit is 0.03 μmol L -1 , and the relative standard deviation of 110 μmol L -1 GSH was 2.6% (n=10). The modified electrode was applied to the determination of GSH in erythrocytes and the results were in agreement with those obtained by a method reported in the literature. (author)

  3. Application of Corrosion- and Fire-Resistant Coating Systems on Buildings 227 and 299 at Rock Island Arsenal

    Science.gov (United States)

    2009-08-01

    event of a fire. The mesh prevents cracking to the steel substrate, which would reduce the insulating properties of the char. The procedure is as...Top Coats: MPI #9, Exterior Alkyd Enamel , Gloss, MPI Gloss Level 6 (i.e., a semi-gloss) • System 2: o Primer: MPI #23, Surface Tolerant Metal...Metal Primer X X MPI Paint #9 Exterior Alkyd Enamel , Gloss X MPI Paint #94 Exterior Alkyd

  4. Characteristics and enhanced antioxidant activity of glycated Morchella esculenta protein isolate

    Directory of Open Access Journals (Sweden)

    Qiang ZHANG

    Full Text Available Abstract Morchella esculenta (L Pers. is a highly valued edible and medicinal fungus that remains underutilized. For this study, the effects of glycation treatment on antioxidant activity and characteristics of the M. esculenta protein isolate (MPI were investigated via the Maillard reaction. Conjugation between MPI and xylose was proven via UV-vis, FT-IR, intrinsic fluorescence analysis, and SDS-PAGE. Amino acid analysis revealed involvement of lysine, arginine and tyrosine in MPI, forming a covalent cross-link with xylose. Differential scanning calorimetry (DSC results showed that glycated MPI (MPIG possesses a more favorable thermal stability compared to native MPI (MPIN, heated MPI (MPIH and an unheated mixture of MPI and xylose (MPI-XM. MPIG exhibited significantly enhanced antioxidant activity compared to MPIN, MPIH, and MPI-XM. These results indicate MPIG can serve as a promising novel source of nutraceutical and functional ingredients that exert antioxidant activity.

  5. 78 FR 40511 - RG Steel Sparrows Point LLC, Formerly Known as Severstal Sparrows Point LLC, a Subsidiary of RG...

    Science.gov (United States)

    2013-07-05

    ... Leased Workers From Echelon Service Company, Sun Associated Industries, Inc., MPI Consultants Llc... Services LLC, Recycling & Treatment Technologies of Baltimore, Llc, and Lafarge North America, Sparrows... leased workers from Echelon Service Company, Sun Associated Industries, Inc., MPI Consultants LLC...

  6. 78 FR 19530 - RG Steel Sparrows Point LLC, Formerly Known as Severstal Sparrows Point LLC, a Subsidiary of RG...

    Science.gov (United States)

    2013-04-01

    ... Leased Workers From Echelon Service Company, Sun Associated Industries, Inc., MPI Consultants LLC... Services LLC, and Recycling & Treatment Technologies of Baltimore, LLC Sparrows Point, Maryland; Amended... Service Company, Sun Associated Industries, Inc., MPI Consultants LLC, Alliance Engineering, Inc...

  7. Myocardial perfusion imaging in Denmark: activity from 1997 to 2001 and current practice

    DEFF Research Database (Denmark)

    Petersen, Claus Leth; Kjaer, Andreas

    2003-01-01

    , and the survey thus covers all MPI performed in Denmark during the period in question. The number of MPI studies (examined patients) was 2,531 in 1997 (0.47 MPI/1,000/year) and 4,961 (0.93 MPI/1,000/year) in 2001, which is a doubling in activity in 5 years. Nineteen (95%) of the Danish departments performed MPI...... in 2001, and 14 (74%) of these reported that activity had increased over the past 5 years. MPI activity was unevenly distributed between hospitals and regions. In 2001, the university hospitals in the central Copenhagen region (capital) accounted for the highest MPI activity (2.00/1,000/year), while......A questionnaire was sent to all departments of nuclear medicine in Denmark (n=20) asking for details of myocardial perfusion imaging (MPI), including the number of patients examined each year from 1997 to 2001 and the current clinical and technical practice. All (100%) departments replied...

  8. Diagnostic value of transesophageal atrial pacing myocardial perfusion imaging in coronary artery disease

    International Nuclear Information System (INIS)

    Jia Yongping; Li Zhiling; Li Yunqian

    1994-01-01

    Transesophageal atrial pacing (TAP) SPECT myocardial perfusion imaging (MPI) with 99m Tc-MIBI was performed in 46 patients with coronary artery disease (CAD) and 15 normal subjects. The results were compared with exercise SPECT MPI. The results showed that the sensitivity and specificity of TAP SPECT to evaluate CAD were 86,96% and 93.33%. TAP SPECT MPI had a significant correlation with exercise SPECT MPI to detect ischemic segment of CAD (r = 0.95)

  9. 32 CFR 637.1 - General.

    Science.gov (United States)

    2010-07-01

    ... (MPI) and Department of the Army Civilian (DAC) detectives/investigators fulfill a special need for an... a dual “detective” force. The separation of investigative responsibilities is very distinct. The MPI... the MPI Program are specially selected, trained, and experienced military or civilian men and women...

  10. Myocardial scintigraphy. Clinical use and consequence in a non-invasive cardiological department

    DEFF Research Database (Denmark)

    Dümcke, Christine Elisabeth; Graff, J; Rasmussen, SPL

    2006-01-01

    to analyse the clinical use of MPI in a university hospital without invasive cardiological laboratory. MATERIAL AND METHODS: In the period 01.01.2002 to 31.12.2003, 259 patients (141 women, 118 men) were referred to MPI from our department of cardiology. RESULTS: Normal MPI was seen in 111 patients (43...

  11. Diagnostic value of early post-exercise 99Tcm-MIBI ECG-gated myocardial perfusion imaging in severe coronary artery disease

    International Nuclear Information System (INIS)

    Li Dianfu; Huang Jun; Feng Jianlin; Cheng Xu; Li Xinli; Cao Kejiang

    2005-01-01

    Objective: To study and compare the diagnostic value in severe coronary artery disease (CAD) of 99 Tc m -methoxyisobutylisonitrile (MIBI) electrocardiogram (ECG)-gated early post-exercise myocardial perfusion imaging (G-MPI) with that of non-ECG-gated myocardial perfusion imaging (NG-MPI). Methods: Two hundred and fifteen suspected CAD patients had undergone G-MPI and coronary artery angiography (CAG) within one month were enrolled and distributed into three-vessel and non-three-vessel CAD groups according to CAG results (≥70%); the diagnostic values in severe CAD of G-MPI and NG-MPI were gained and compared to determine which one of the two protocols would be superior in identification of severe three-vessel CAD. Results: When the ≥70% diameter stenosis CAG was the diagnostic standard of severe CAD, the sensitivity of G-MPI and NG-MPI in the diagnosis of severe CAD were 95.3% (143/150) and 90.7% (136/150, χ 2 =2.509, P=0.113), but when the comparison specifically pinpointed to severe three-vessel CAD, there was significant difference between G-MPI [100%(51/51)] and NG-MPI [92.2% (47/51), χ 2 =4.163, P=0.041]. Diagnostic specificity of G-MPI was 80.0% and that of NG-MPI was 72.3% (χ 2 =1.059, P=0.303). Conclusions: The incremental diagnostic sensitivity of G-MPI adding to the NG-MPI in the diagnosis of severe CAD was mainly from the three-vessel subgroup patients. Exercise stress G-MPI has better diagnostic value in severe three-vessel CAD patients than NG-MPI. (authors)

  12. A comparative study of 99Tcm-MIBI exercise myocardial perfusion imaging and the coronary arteriography in the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Huang Xiaohong; Yan Aiping; Li Yuren; Hou Zhenwen; Jiang Ningyi; Lu Xianping

    2003-01-01

    Objective: A comparative evaluation of 99 Tc m -MIBI exercise myocardial perfusion imaging (MPI) and coronary arteriography (CAG) in diagnosis of coronary artery disease. Methods: MPI and CAG were performed on 92 patients with clinical equivocal diagnosis of coronary artery disease. The results were comparatively studied. Results: The sensitivity and specificity of MPI were 83.9% and 69.1%. Both modalities matched in 78.3% cases. Conclusion: MPI offers useful information for the diagnosis of coronary artery disease. And patients with a normal MPI don't need a further coronary angiography

  13. Magnetic Particle Imaging for Real-Time Perfusion Imaging in Acute Stroke.

    Science.gov (United States)

    Ludewig, Peter; Gdaniec, Nadine; Sedlacik, Jan; Forkert, Nils D; Szwargulski, Patryk; Graeser, Matthias; Adam, Gerhard; Kaul, Michael G; Krishnan, Kannan M; Ferguson, R Matthew; Khandhar, Amit P; Walczak, Piotr; Fiehler, Jens; Thomalla, Götz; Gerloff, Christian; Knopp, Tobias; Magnus, Tim

    2017-10-24

    The fast and accurate assessment of cerebral perfusion is fundamental for the diagnosis and successful treatment of stroke patients. Magnetic particle imaging (MPI) is a new radiation-free tomographic imaging method with a superior temporal resolution, compared to other conventional imaging methods. In addition, MPI scanners can be built as prehospital mobile devices, which require less complex infrastructure than computed tomography (CT) and magnetic resonance imaging (MRI). With these advantages, MPI could accelerate the stroke diagnosis and treatment, thereby improving outcomes. Our objective was to investigate the capabilities of MPI to detect perfusion deficits in a murine model of ischemic stroke. Cerebral ischemia was induced by inserting of a microfilament in the internal carotid artery in C57BL/6 mice, thereby blocking the blood flow into the medial cerebral artery. After the injection of a contrast agent (superparamagnetic iron oxide nanoparticles) specifically tailored for MPI, cerebral perfusion and vascular anatomy were assessed by the MPI scanner within seconds. To validate and compare our MPI data, we performed perfusion imaging with a small animal MRI scanner. MPI detected the perfusion deficits in the ischemic brain, which were comparable to those with MRI but in real-time. For the first time, we showed that MPI could be used as a diagnostic tool for relevant diseases in vivo, such as an ischemic stroke. Due to its shorter image acquisition times and increased temporal resolution compared to that of MRI or CT, we expect that MPI offers the potential to improve stroke imaging and treatment.

  14. Combined preclinical magnetic particle imaging and magnetic resonance imaging. Initial results in mice

    International Nuclear Information System (INIS)

    Kaul, M.G.; Mummert, T.; Jung, C.; Raabe, N.; Ittrich, H.; Adam, G.; Heinen, U.; Reitmeier, A.

    2015-01-01

    Magnetic particle imaging (MPI) is a new radiologic imaging modality. For the first time, a commercial preclinical scanner is installed. The goal of this study was to establish a workflow between MPI and magnetic resonance imaging (MRI) scanners for a complete in vivo examination of a mouse and to generate the first co-registered in vivo MR-MP images. The in vivo examination of five mice were performed on a preclinical MPI scanner and a 7 Tesla preclinical MRI system. MRI measurements were used for anatomical referencing and validation of the injection of superparamagnetic iron oxide (SPIO) particles during a dynamic MPI scan. We extracted MPI data of the injection phase and co-registered it with MRI data. A workflow process for a combined in vivo MRI and MPI examination was established. A successful injection of ferucarbotran was proven in MPI and MRI. MR-MPI co-registration allocated the SPIOs in the inferior vena cava and the heart during and shortly after the injection. The acquisition of preclinical MPI and MRI data is feasible and allows the combined analysis of MR-MPI information.

  15. Combined preclinical magnetic particle imaging and magnetic resonance imaging. Initial results in mice

    Energy Technology Data Exchange (ETDEWEB)

    Kaul, M.G.; Mummert, T.; Jung, C.; Raabe, N.; Ittrich, H.; Adam, G. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Weber, O. [Philips Medical Systems DMC GmbH, Hamburg (Germany); Heinen, U. [Bruker BioSpin MRI GmbH, Ettlingen (Germany); Reitmeier, A. [Medical Center Hamburg-Eppendorf, Hamburg (Germany). Animal Facility; Knopp, T. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Hamburg University of Technology, Hamburg (Germany)

    2015-05-15

    Magnetic particle imaging (MPI) is a new radiologic imaging modality. For the first time, a commercial preclinical scanner is installed. The goal of this study was to establish a workflow between MPI and magnetic resonance imaging (MRI) scanners for a complete in vivo examination of a mouse and to generate the first co-registered in vivo MR-MP images. The in vivo examination of five mice were performed on a preclinical MPI scanner and a 7 Tesla preclinical MRI system. MRI measurements were used for anatomical referencing and validation of the injection of superparamagnetic iron oxide (SPIO) particles during a dynamic MPI scan. We extracted MPI data of the injection phase and co-registered it with MRI data. A workflow process for a combined in vivo MRI and MPI examination was established. A successful injection of ferucarbotran was proven in MPI and MRI. MR-MPI co-registration allocated the SPIOs in the inferior vena cava and the heart during and shortly after the injection. The acquisition of preclinical MPI and MRI data is feasible and allows the combined analysis of MR-MPI information.

  16. Mathematical analysis of the 1D model and reconstruction schemes for magnetic particle imaging

    Science.gov (United States)

    Erb, W.; Weinmann, A.; Ahlborg, M.; Brandt, C.; Bringout, G.; Buzug, T. M.; Frikel, J.; Kaethner, C.; Knopp, T.; März, T.; Möddel, M.; Storath, M.; Weber, A.

    2018-05-01

    Magnetic particle imaging (MPI) is a promising new in vivo medical imaging modality in which distributions of super-paramagnetic nanoparticles are tracked based on their response in an applied magnetic field. In this paper we provide a mathematical analysis of the modeled MPI operator in the univariate situation. We provide a Hilbert space setup, in which the MPI operator is decomposed into simple building blocks and in which these building blocks are analyzed with respect to their mathematical properties. In turn, we obtain an analysis of the MPI forward operator and, in particular, of its ill-posedness properties. We further get that the singular values of the MPI core operator decrease exponentially. We complement our analytic results by some numerical studies which, in particular, suggest a rapid decay of the singular values of the MPI operator.

  17. Optimizing Blocking and Nonblocking Reduction Operations for Multicore Systems: Hierarchical Design and Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Gorentla Venkata, Manjunath [ORNL; Shamis, Pavel [ORNL; Graham, Richard L [ORNL; Ladd, Joshua S [ORNL; Sampath, Rahul S [ORNL

    2013-01-01

    Many scientific simulations, using the Message Passing Interface (MPI) programming model, are sensitive to the performance and scalability of reduction collective operations such as MPI Allreduce and MPI Reduce. These operations are the most widely used abstractions to perform mathematical operations over all processes that are part of the simulation. In this work, we propose a hierarchical design to implement the reduction operations on multicore systems. This design aims to improve the efficiency of reductions by 1) tailoring the algorithms and customizing the implementations for various communication mechanisms in the system 2) providing the ability to configure the depth of hierarchy to match the system architecture, and 3) providing the ability to independently progress each of this hierarchy. Using this design, we implement MPI Allreduce and MPI Reduce operations (and its nonblocking variants MPI Iallreduce and MPI Ireduce) for all message sizes, and evaluate on multiple architectures including InfiniBand and Cray XT5. We leverage and enhance our existing infrastructure, Cheetah, which is a framework for implementing hierarchical collective operations to implement these reductions. The experimental results show that the Cheetah reduction operations outperform the production-grade MPI implementations such as Open MPI default, Cray MPI, and MVAPICH2, demonstrating its efficiency, flexibility and portability. On Infini- Band systems, with a microbenchmark, a 512-process Cheetah nonblocking Allreduce and Reduce achieves a speedup of 23x and 10x, respectively, compared to the default Open MPI reductions. The blocking variants of the reduction operations also show similar performance benefits. A 512-process nonblocking Cheetah Allreduce achieves a speedup of 3x, compared to the default MVAPICH2 Allreduce implementation. On a Cray XT5 system, a 6144-process Cheetah Allreduce outperforms the Cray MPI by 145%. The evaluation with an application kernel, Conjugate

  18. Fundamental studies of molecular multiphoton ionization

    International Nuclear Information System (INIS)

    Miller, J.C.; Compton, R.N.

    1984-04-01

    For several years the authors have performed fundamental studies of molecular multiphoton ionization (MPI). We will present a potpourri of techniques and results chosen to illustrate the interesting complexities of molecular MPI. Techniques used include time-of-flight mass spectroscopy, photoelectron spectroscopy, supersonic expansion cooling of molecular beams, harmonic generation, two-color laser MPI, and polarization spectroscopy. Whenever possible the relevance of these results to resonance ionization spectroscopy schemes will be delineated. 23 references, 10 figures

  19. Common-mode rejection in Martin-Puplett spectrometers for astronomical observations at millimeter wavelengths.

    Science.gov (United States)

    D'Alessandro, Giuseppe; de Bernardis, Paolo; Masi, Silvia; Schillaci, Alessandro

    2015-11-01

    The Martin-Puplett interferometer (MPI) is a differential Fourier transform spectrometer that measures the difference between spectral brightness at two input ports. This unique feature makes the MPI an optimal zero instrument, able to detect small brightness gradients embedded in a large common background. In this paper, we experimentally investigate the common-mode rejection achievable in the MPI at millimeter wavelengths, and discuss the use of the instrument to measure the spectrum of cosmic microwave background anisotropy.

  20. Consumo de medicamentos en mayores de 65 años en Oporto (Portugal y riesgo de prescripción de medicamentos potencialmente inapropiados

    Directory of Open Access Journals (Sweden)

    Andreia Eiras

    2016-02-01

    Conclusiones: La prescripción de fármacos, polimedicación y uso de MPI son muy elevados en la población portuguesa estudiada. La polimedicación es el factor más importante asociado al consumo de MPI. La prescripción de ansiolíticos, antidepresivos o antiinflamatorios debe hacerse con mucho cuidado ante el riesgo de los MPI.

  1. The Fetal Modified Myocardial Performance Index: Is Automation the Future?

    Directory of Open Access Journals (Sweden)

    Priya Maheshwari

    2015-01-01

    Full Text Available The fetal modified myocardial performance index (Mod-MPI is a noninvasive, pulsed-wave Doppler-derived measure of global myocardial function. This review assesses the progress in technical refinements of its measurement and the potential for automation to be the crucial next step. The Mod-MPI is a ratio of isovolumetric to ejection time cardiac time intervals, and the potential for the left ventricular Mod-MPI as a tool to clinically assess fetal cardiac function is well-established. However, there are wide variations in published reference ranges, as (1 a standardised method of selecting cardiac time intervals used in Mod-MPI calculation has not been established; (2 cardiac time interval measurement currently requires manual, inherently subjective placement of callipers on Doppler ultrasound waveforms; and (3 ultrasound machine settings and ultrasound system type have been found to affect Mod-MPI measurement. Collectively these factors create potential for significant inter- and intraobserver measurement variability. Automated measurement of the Mod-MPI may be the next key development which propels the Mod-MPI into routine clinical use. A novel automated system of Mod-MPI measurement is briefly presented and its implications for the future of the Mod-MPI in fetal cardiology are discussed.

  2. High coronary artery calcium score affects clinical outcome despite normal stress myocardial perfusion imaging and normal left ventricular ejection fraction

    DEFF Research Database (Denmark)

    Madsen, Claus Juul; Andersen, Kim F; Zerahn, Bo

    2013-01-01

    Normal myocardial perfusion imaging (MPI) indicates a low risk for cardiac death and new ischaemic events. However, the impact of normal MPI combined with a high coronary artery calcium score (CACS) is not clear. The aims of this study were to evaluate the risk of severely elevated CACS and to id......Normal myocardial perfusion imaging (MPI) indicates a low risk for cardiac death and new ischaemic events. However, the impact of normal MPI combined with a high coronary artery calcium score (CACS) is not clear. The aims of this study were to evaluate the risk of severely elevated CACS...

  3. Exanthema after a stress Tc-99m sestamibi study: continue with a rest sestamibi study?

    DEFF Research Database (Denmark)

    Hesse, Birger; Vinberg, Niels; Mosbech, Holger

    2011-01-01

    Purpose:  A mild allergic reaction assumed to be caused by injection of Tc-99m sestamibi for a stress myocardial perfusion imaging (MPI) is presented. We want to discuss the risk involved in completing the MPI with another sestamibi injection, and the precautions and possible treatment in case...... of a further reaction. Material and methods:  A patient experienced a maculo-papular exanthema, i.e. a mild, probably allergic, adverse event (AE) after a stress MPI including administration of a dose of Tc-99m sestamibi. A rest MPI was needed to decide whether coronary bypass surgery should be performed...

  4. Usefulness of the myocardial performance index determined by tissue Doppler imaging m-mode for predicting mortality in the general population

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Møgelvang, Rasmus; Haahr-Pedersen, Sune Ammentorp

    2011-01-01

    The objective of this study was to evaluate the prognostic value of the myocardial performance index (MPI), assessed by color-coded tissue Doppler imaging (TDI) M-mode through the anterior mitral leaflet. Color TDI M-mode through the mitral leaflet is an easy, very fast, and precise method...... ventricular in- and outflow using standard procedures (MPI(conv)) and by color-coded TDI M-mode through the mitral leaflet in the apical 4-chamber view (MPI(TDI)). MPI(TDI) was increased in subjects with coronary heart disease (CHD) compared to controls, even after multivariable adjustment (p

  5. Mycobacterium tuberculosis Infection and Innate Responses in a New Model of Lung Alveolar Macrophages.

    Science.gov (United States)

    Woo, Minjeong; Wood, Connor; Kwon, Doyoon; Park, Kyu-Ho Paul; Fejer, György; Delorme, Vincent

    2018-01-01

    Lung alveolar macrophages (AMs) are in the first line of immune defense against respiratory pathogens and play key roles in the pathogenesis of Mycobacterium tuberculosis ( Mtb ) in humans. Nevertheless, AMs are available only in limited amounts for in vitro studies, which hamper the detailed molecular understanding of host- Mtb interactions in these macrophages. The recent establishment of the self-renewing and primary Max Planck Institute (MPI) cells, functionally very close to lung AMs, opens unique opportunities for in vitro studies of host-pathogen interactions in respiratory diseases. Here, we investigated the suitability of MPI cells as a host cell system for Mtb infection. Bacterial, cellular, and innate immune features of MPI cells infected with Mtb were characterized. Live bacteria were readily internalized and efficiently replicated in MPI cells, similarly to primary murine macrophages and other cell lines. MPI cells were also suitable for the determination of anti-tuberculosis (TB) drug activity. The primary innate immune response of MPI cells to live Mtb showed significantly higher and earlier induction of the pro-inflammatory cytokines TNFα, interleukin 6 (IL-6), IL-1α, and IL-1β, as compared to stimulation with heat-killed (HK) bacteria. MPI cells previously showed a lack of induction of the anti-inflammatory cytokine IL-10 to a wide range of stimuli, including HK Mtb . By contrast, we show here that live Mtb is able to induce significant amounts of IL-10 in MPI cells. Autophagy experiments using light chain 3B immunostaining, as well as LysoTracker labeling of acidic vacuoles, demonstrated that MPI cells efficiently control killed Mtb by elimination through phagolysosomes. MPI cells were also able to accumulate lipid droplets in their cytoplasm following exposure to lipoproteins. Collectively, this study establishes the MPI cells as a relevant, versatile host cell model for TB research, allowing a deeper understanding of AMs functions in this

  6. SPECT myocardial perfusion imaging. Long-term prognostic value in diabetic patients with and without coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Koehli, M. [Dept. of Endocrinology, Diabetology and Metabolism, Univ. Hospital Lausanne (Switzerland); Dept. of Nuclear Medicine, Univ. Hospital Lausanne (Switzerland); Monbaron, D.; Gaillard, R.C.; Ruiz, J. [Dept. of Endocrinology, Diabetology and Metabolism, Univ. Hospital Lausanne (Switzerland); Prior, J.O.; Bischof Delaloye, A. [Dept. of Nuclear Medicine, Univ. Hospital Lausanne (Switzerland); Calcagni, M.L. [Dept. of Nuclear Medicine, Univ. Hospital Lausanne (Switzerland); Dept. of Cardiology, Univ. Hospital Lausanne (Switzerland); Fivaz-Arbane, M.; Stauffer, J.C. [Inst. of Nuclear Medicine, Univ. Cattolica del Sacro Cuore, Roma (Italy)

    2006-07-01

    Aim: To determine the long-term prognostic value of SPECT myocardial perfusion imaging (MPI) for the occurrence of cardiovascular events in diabetic patients. Patients, methods: SPECT MPI of 210 consecutive Caucasian diabetic patients were analysed using Kaplan-Meier event-free survival curve and independent predictors were determined by Cox multivariate analyses. Results: Follow-up was complete in 200 (95%) patients with a median period of 3.0 years (0.8-5.0). The population was composed of 114 (57%) men, age 65 {+-} 10 years, 181 (90.5%) type 2 diabetes mellitus, 50 (25%) with a history of coronary artery disease (CAD) and 98 (49%) presenting chest pain prior to MPI. The prevalence of abnormal MPI was 58%. Patients with a normal MPI had neither cardiac death, nor myocardial infarction, independently of a history of coronary artery disease or chest pain. Among the independent predictors of cardiac death and myocardial infarction, the strongest was abnormal MPI (p < 0.0001), followed by history of CAD (Hazard Ratio (HR) = 15.9; p = 0.0001), diabetic retinopathy (HR = 10.0; p = 0.001) and inability to exercise (HR = 7.7; p = 0.02). Patients with normal MPI had a low revascularisation rate of 2.4% during the follow-up period. Compared to normal MPI, cardiovascular events increased 5.2 fold for reversible defects, 8.5 fold for fixed defects and 20.1 fold for the association of both defects. Conclusion: Diabetic patients with normal MPI had on excellent prognosis independently of history of CAD. On the opposite, an abnormal MPI led to a > 5-fold increase in cardiovascular events. This emphasizes the value of SPECT MPI in predicting and risk-stratifying cardiovascular events in diabetic patients. (orig.)

  7. Mycobacterium tuberculosis Infection and Innate Responses in a New Model of Lung Alveolar Macrophages

    Directory of Open Access Journals (Sweden)

    Minjeong Woo

    2018-03-01

    Full Text Available Lung alveolar macrophages (AMs are in the first line of immune defense against respiratory pathogens and play key roles in the pathogenesis of Mycobacterium tuberculosis (Mtb in humans. Nevertheless, AMs are available only in limited amounts for in vitro studies, which hamper the detailed molecular understanding of host-Mtb interactions in these macrophages. The recent establishment of the self-renewing and primary Max Planck Institute (MPI cells, functionally very close to lung AMs, opens unique opportunities for in vitro studies of host-pathogen interactions in respiratory diseases. Here, we investigated the suitability of MPI cells as a host cell system for Mtb infection. Bacterial, cellular, and innate immune features of MPI cells infected with Mtb were characterized. Live bacteria were readily internalized and efficiently replicated in MPI cells, similarly to primary murine macrophages and other cell lines. MPI cells were also suitable for the determination of anti-tuberculosis (TB drug activity. The primary innate immune response of MPI cells to live Mtb showed significantly higher and earlier induction of the pro-inflammatory cytokines TNFα, interleukin 6 (IL-6, IL-1α, and IL-1β, as compared to stimulation with heat-killed (HK bacteria. MPI cells previously showed a lack of induction of the anti-inflammatory cytokine IL-10 to a wide range of stimuli, including HK Mtb. By contrast, we show here that live Mtb is able to induce significant amounts of IL-10 in MPI cells. Autophagy experiments using light chain 3B immunostaining, as well as LysoTracker labeling of acidic vacuoles, demonstrated that MPI cells efficiently control killed Mtb by elimination through phagolysosomes. MPI cells were also able to accumulate lipid droplets in their cytoplasm following exposure to lipoproteins. Collectively, this study establishes the MPI cells as a relevant, versatile host cell model for TB research, allowing a deeper understanding of AMs functions

  8. A zebrafish model of congenital disorders of glycosylation with phosphomannose isomerase deficiency reveals an early opportunity for corrective mannose supplementation

    Directory of Open Access Journals (Sweden)

    Jaime Chu

    2013-01-01

    Individuals with congenital disorders of glycosylation (CDG have recessive mutations in genes required for protein N-glycosylation, resulting in multi-systemic disease. Despite the well-characterized biochemical consequences in these individuals, the underlying cellular defects that contribute to CDG are not well understood. Synthesis of the lipid-linked oligosaccharide (LLO, which serves as the sugar donor for the N-glycosylation of secretory proteins, requires conversion of fructose-6-phosphate to mannose-6-phosphate via the phosphomannose isomerase (MPI enzyme. Individuals who are deficient in MPI present with bleeding, diarrhea, edema, gastrointestinal bleeding and liver fibrosis. MPI-CDG patients can be treated with oral mannose supplements, which is converted to mannose-6-phosphate through a minor complementary metabolic pathway, restoring protein glycosylation and ameliorating most symptoms, although liver disease continues to progress. Because Mpi deletion in mice causes early embryonic lethality and thus is difficult to study, we used zebrafish to establish a model of MPI-CDG. We used a morpholino to block mpi mRNA translation and established a concentration that consistently yielded 13% residual Mpi enzyme activity at 4 days post-fertilization (dpf, which is within the range of MPI activity detected in fibroblasts from MPI-CDG patients. Fluorophore-assisted carbohydrate electrophoresis detected decreased LLO and N-glycans in mpi morphants. These deficiencies resulted in 50% embryonic lethality by 4 dpf. Multi-systemic abnormalities, including small eyes, dysmorphic jaws, pericardial edema, a small liver and curled tails, occurred in 82% of the surviving larvae. Importantly, these phenotypes could be rescued with mannose supplementation. Thus, parallel processes in fish and humans contribute to the phenotypes caused by Mpi depletion. Interestingly, mannose was only effective if provided prior to 24 hpf. These data provide insight into treatment efficacy

  9. Parallel Sparse Matrix - Vector Product

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd

    This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...

  10. Metastasis is strongly reduced by the matrix metalloproteinase inhibitor Galardin in the MMTV-PymT transgenic breast cancer model

    DEFF Research Database (Denmark)

    Almholt, Kasper; Juncker-Jensen, Anna; Lærum, Ole Didrik

    2008-01-01

    Matrix metalloproteinases (MMP) have several roles that influence cancer progression and dissemination. However, low molecular weight metalloproteinase inhibitors (MPI) have not yet been tested in transgenic/spontaneous metastasis models. We have tested Galardin/GM6001, a potent MPI that reacts w...

  11. Murine polyomavirus virus-like particles carrying full-length human PSA protect BALB/c mice from outgrowth of a PSA expressing tumor.

    Directory of Open Access Journals (Sweden)

    Mathilda Eriksson

    Full Text Available Virus-like particles (VLPs consist of capsid proteins from viruses and have been shown to be usable as carriers of protein and peptide antigens for immune therapy. In this study, we have produced and assayed murine polyomavirus (MPyV VLPs carrying the entire human Prostate Specific Antigen (PSA (PSA-MPyVLPs for their potential use for immune therapy in a mouse model system. BALB/c mice immunized with PSA-MPyVLPs were only marginally protected against outgrowth of a PSA-expressing tumor. To improve protection, PSA-MPyVLPs were co-injected with adjuvant CpG, either alone or loaded onto murine dendritic cells (DCs. Immunization with PSA-MPyVLPs loaded onto DCs in the presence of CpG was shown to efficiently protect mice from tumor outgrowth. In addition, cellular and humoral immune responses after immunization were examined. PSA-specific CD4(+ and CD8(+ cells were demonstrated, but no PSA-specific IgG antibodies. Vaccination with DCs loaded with PSA-MPyVLPs induced an eight-fold lower titre of anti-VLP antibodies than vaccination with PSA-MPyVLPs alone. In conclusion, immunization of BALB/c mice with PSA-MPyVLPs, loaded onto DCs and co-injected with CpG, induces an efficient PSA-specific tumor protective immune response, including both CD4(+ and CD8(+ cells with a low induction of anti-VLP antibodies.

  12. the use of multivariat statistical methode to study the aquifer system ...

    African Journals Online (AJOL)

    A. Bettahar

    2017-09-01

    Sep 1, 2017 ... -2. ) that gathers the drillings. (MPII4, MPII19, MPI8, MPI4) and the drilling of the third layer Eocene (OE1) characterized by high salinity (EC varies between 5500 and 6000μs / cm), the sodium chloride facies, or sulfated sodium caused by the dissolution of evaporate rocks and gypsum that characterizes.

  13. The clinical value of adenosine triphosphate stress myocardial perfusion tomography for detecting coronary artery disease

    International Nuclear Information System (INIS)

    Yao Zhiming; He Qing; Qu Wanying; Yu Xue; Han Lijun; Yu Zhiguo; Li Wei; Zeng Xuezhai; Zhu Ming; Zhao Hongshan

    2002-01-01

    Objective: To study the clinical value of adenosine triphosphate stress myocardial perfusion tomography imaging (ATP-MPI) in detection of coronary artery disease (CAD). Methods: There were 278 patients underwent ATP-MPI, 51 patients of them also underwent coronary angiography (CAG). Seventy-three patients underwent stress-rest myocardial perfusion tomography imaging with multi-stage submaximal exercise test (ST-MPI) and CAG serving as control group. Results: 1) Side effects: there were 11 different symptoms and atrioventricular conduction block (10 patients), sinoatrial conduction block (2 patients) occurred during ATP stress. Allopathy or interruption of ATP stress did not happen. 2) The sensitivity and specificity of ATP-MPI in detection of CAD were 97.1% and 82.4%, respectively, and those in detection of ≥50% narrowing coronary artery were 91.0% and 94.7%, respectively. 3) In patients without myocardial infarction, the sensitivity and specificity of ATP-MPI in detection of myocardial ischemia were comparable to those of ST-MPI. Conclusion: ATP-MPI is an accurate, safe modality and is comparable to ST-MPI in the detection of CAD

  14. Murine Polyomavirus Virus-Like Particles Carrying Full-Length Human PSA Protect BALB/c Mice from Outgrowth of a PSA Expressing Tumor

    Science.gov (United States)

    Eriksson, Mathilda; Andreasson, Kalle; Weidmann, Joachim; Lundberg, Kajsa; Tegerstedt, Karin

    2011-01-01

    Virus-like particles (VLPs) consist of capsid proteins from viruses and have been shown to be usable as carriers of protein and peptide antigens for immune therapy. In this study, we have produced and assayed murine polyomavirus (MPyV) VLPs carrying the entire human Prostate Specific Antigen (PSA) (PSA-MPyVLPs) for their potential use for immune therapy in a mouse model system. BALB/c mice immunized with PSA-MPyVLPs were only marginally protected against outgrowth of a PSA-expressing tumor. To improve protection, PSA-MPyVLPs were co-injected with adjuvant CpG, either alone or loaded onto murine dendritic cells (DCs). Immunization with PSA-MPyVLPs loaded onto DCs in the presence of CpG was shown to efficiently protect mice from tumor outgrowth. In addition, cellular and humoral immune responses after immunization were examined. PSA-specific CD4+ and CD8+ cells were demonstrated, but no PSA-specific IgG antibodies. Vaccination with DCs loaded with PSA-MPyVLPs induced an eight-fold lower titre of anti-VLP antibodies than vaccination with PSA-MPyVLPs alone. In conclusion, immunization of BALB/c mice with PSA-MPyVLPs, loaded onto DCs and co-injected with CpG, induces an efficient PSA-specific tumor protective immune response, including both CD4+ and CD8+ cells with a low induction of anti-VLP antibodies. PMID:21858228

  15. Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Ming-Che Wu

    2015-11-01

    Full Text Available We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI with thallium-201 (Tl-201 and technetium-99m-sestamibi (MIBI protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF, rest EF, and change in EF (ΔEF were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group.

  16. Outbreak of Mysterious Illness Among Hospital Staff

    DEFF Research Database (Denmark)

    Jacobsen, Peter; Ebbehøj, Niels Erik

    2016-01-01

    BACKGROUND: Hospitals are rarely reported as settings for mass psychogenic illness (MPI). The present report scrutinizes an outbreak of probable MPI among hospital staff, with medical intervention reinforcing the course of the illness. CASE REPORT: Four of seven staff members in an emergency...

  17. 78 FR 9793 - Airworthiness Directives; Bell Helicopter Textron Helicopters

    Science.gov (United States)

    2013-02-12

    ...-numbered main rotor hub inboard strap fittings (fittings). This AD requires magnetic particle inspecting... identified in this AD, contact Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, TX 76101, telephone..., perform a magnetic particle inspection (MPI) of each fitting for a crack. If an MPI was already performed...

  18. 75 FR 5677 - Airworthiness Directives; The Boeing Company Model 767-200, -300, and -300F Series Airplanes

    Science.gov (United States)

    2010-02-04

    ... AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H... a magnetic particle inspection (MPI) in accordance with Part 4, ``Magnetic Particle Inspection of... November 5, 2009, or MPI in accordance with Part 4, ``Magnetic Particle Inspection of the Midspar Fuse Pin...

  19. Effect of caffeine on SPECT myocardial perfusion imaging during regadenoson pharmacologic stress: rationale and design of a prospective, randomized, multicenter study.

    Science.gov (United States)

    Tejani, Furqan H; Thompson, Randall C; Iskandrian, Ami E; McNutt, Bruce E; Franks, Billy

    2011-02-01

    Caffeine attenuates the coronary hyperemic response to adenosine by competitive A₂(A) receptor blockade. This study aims to determine whether oral caffeine administration compromises diagnostic accuracy in patients undergoing vasodilator stress myocardial perfusion imaging (MPI) with regadenoson, a selective adenosine A(2A) agonist. This multicenter, randomized, double-blind, placebo-controlled, parallel-group study includes patients with suspected coronary artery disease who regularly consume caffeine. Each participant undergoes three SPECT MPI studies: a rest study on day 1 (MPI-1); a regadenoson stress study on day 3 (MPI-2), and a regadenoson stress study on day 5 with double-blind administration of oral caffeine 200 or 400 mg or placebo capsules (MPI-3; n = 90 per arm). Only participants with ≥ 1 reversible defect on the second MPI study undergo the subsequent stress MPI test. The primary endpoint is the difference in the number of reversible defects on the two stress tests using a 17-segment model. Pharmacokinetic/pharmacodynamic analyses will evaluate the effect of caffeine on the regadenoson exposure-response relationship. Safety will also be assessed. The results of this study will show whether the consumption of caffeine equivalent to 2-4 cups of coffee prior to an MPI study with regadenoson affects the diagnostic validity of stress testing (ClinicalTrials.gov number, NCT00826280).

  20. Temperature dependence in magnetic particle imaging

    Science.gov (United States)

    Wells, James; Paysen, Hendrik; Kosch, Olaf; Trahms, Lutz; Wiekhorst, Frank

    2018-05-01

    Experimental results are presented demonstrating how temperature can influence the dynamics of magnetic nanoparticles (MNPs) in liquid suspension, when exposed to alternating magnetic fields in the kilohertz frequency range. The measurements used to probe the nanoparticle systems are directly linked to both the emerging biomedical technique of magnetic particle imaging (MPI), and to the recently proposed concept of remote nanoscale thermometry using MNPs under AC field excitation. Here, we report measurements on three common types of MNPs, two of which are currently leading candidates for use as tracers in MPI. Using highly-sensitive magnetic particle spectroscopy (MPS), we demonstrate significant and divergent thermal dependences in several key measures used in the evaluation of MNP dynamics for use in MPI and other applications. The temperature range studied was between 296 and 318 Kelvin, making our findings of particular importance for MPI and other biomedical technologies. Furthermore, we report the detection of the same temperature dependences in measurements conducted using the detection coils within an operational preclinical MPI scanner. This clearly shows the importance of considering temperature during MPI development, and the potential for temperature-resolved MPI using this system. We propose possible physical explanations for the differences in the behaviors observed between the different particle types, and discuss our results in terms of the opportunities and concerns they raise for MPI and other MNP based technologies.

  1. EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT

    DEFF Research Database (Denmark)

    Verberne, Hein J; Acampa, Wanda; Anagnostopoulos, Constantinos

    2015-01-01

    Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated ...

  2. A hybrid version of swan for fast and efficient practical wave modelling

    NARCIS (Netherlands)

    M. Genseberger (Menno); J. Donners

    2016-01-01

    htmlabstractIn the Netherlands, for coastal and inland water applications, wave modelling with SWAN has become a main ingredient. However, computational times are relatively high. Therefore we investigated the parallel efficiency of the current MPI and OpenMP versions of SWAN. The MPI version is

  3. Relaxation in x-space magnetic particle imaging.

    Science.gov (United States)

    Croft, Laura R; Goodwill, Patrick W; Conolly, Steven M

    2012-12-01

    Magnetic particle imaging (MPI) is a new imaging modality that noninvasively images the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIOs). MPI has demonstrated high contrast and zero attenuation with depth, and MPI promises superior safety compared to current angiography methods, X-ray, computed tomography, and magnetic resonance imaging angiography. Nanoparticle relaxation can delay the SPIO magnetization, and in this work we investigate the open problem of the role relaxation plays in MPI scanning and its effect on the image. We begin by amending the x-space theory of MPI to include nanoparticle relaxation effects. We then validate the amended theory with experiments from a Berkeley x-space relaxometer and a Berkeley x-space projection MPI scanner. Our theory and experimental data indicate that relaxation reduces SNR and asymmetrically blurs the image in the scanning direction. While relaxation effects can have deleterious effects on the MPI scan, we show theoretically and experimentally that x-space reconstruction remains robust in the presence of relaxation. Furthermore, the role of relaxation in x-space theory provides guidance as we develop methods to minimize relaxation-induced blurring. This will be an important future area of research for the MPI community.

  4. Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems

    OpenAIRE

    Shehzad, Danish; Bozkuş, Zeki

    2016-01-01

    Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collecti...

  5. A comparative electrochemical study of electrosorbed 2- and 4 ...

    Indian Academy of Sciences (India)

    mercaptopyridine (2 Mpy) and 4-mercaptopyridine (4 Mpy) dissolved in either water or an aqueous solution of 0.1 M H2SO4 on a polycrystalline gold electrode has been investigated in an aqueous electrolyte solution (0.5 M H2SO4) using cyclic ...

  6. CT myocardial perfusion imaging. Ready for prime time?

    Energy Technology Data Exchange (ETDEWEB)

    Takx, Richard A.P.; Celeng, Csilla [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Ashley River Tower, Heart and Vascular Center, Charleston, SC (United States)

    2018-03-15

    The detection of functional coronary artery stenosis with coronary CT angiography (CCTA) is suboptimal. Additional CT myocardial perfusion imaging (CT-MPI) may be helpful to identify patients with myocardial ischaemia in whom coronary revascularization therapy would be beneficial. CT-MPI adds incremental diagnostic and prognostic value over obstructive disease on CCTA. It allows for the quantitation of myocardial blood flow and calculation of coronary flow reserve and shows good correlation with {sup 15}O-H{sub 2}O positron emission tomography and invasive fractional flow reserve. In addition, patients prefer CCTA/CT-MPI over SPECT, MRI and invasive coronary angiography. CT-MPI is ready for clinical use for detecting myocardial ischaemia caused by obstructive disease. Nevertheless, the clinical utility of CT-MPI to identify ischaemia in patients with non-obstructive/microvascular disease still has to be established. (orig.)

  7. arXiv Proceedings of the Sixth International Workshop on Multiple Partonic Interactions at the Large Hadron Collider

    CERN Document Server

    Astalos, R.; Bartalini, P.; Belyaev, I.; Bierlich, Ch.; Blok, B.; Buckley, A.; Ceccopieri, F.A.; Cherednikov, I.; Christiansen, J.R.; Ciangottini, D.; Deak, M.; Ducloue, B.; Field, R.; Gaunt, J.R.; Golec-Biernat, K.; Goerlich, L.; Grebenyuk, A.; Gueta, O.; Gunnellini, P.; Helenius, I.; Jung, H.; Kar, D.; Kepka, O.; Klusek-Gawenda, M.; Knutsson, A.; Kotko, P.; Krasny, M.W.; Kutak, K.; Lewandowska, E.; Lykasov, G.; Maciula, R.; Moraes, A.M.; Martin, T.; Mitsuka, G.; Motyka, L.; Myska, M.; Otwinowski, J.; Pierog, T.; Pleskot, V.; Rinaldi, M.; Schafer, W.; Siodmok, A.; Sjostrand, T.; Snigirev, A.; Stasto, A.; Staszewski, R.; Stebel, T.; Strikman, M.; Szczurek, A.; Treleani, D.; Trzebinski, M.; van Haevermaet, H.; van Hameren, A.; van Mechelen, P.; Waalewijn, W.; Wang, W.Y.; MPI@LHC 2014

    2014-01-01

    Multiple Partonic Interactions are often crucial for interpreting results obtained at the Large Hadron Collider (LHC). The quest for a sound understanding of the dynamics behind MPI - particularly at this time when the LHC is due to start its "Run II" operations - has focused the aim of this workshop. MPI@LHC2014 concentrated mainly on the phenomenology of LHC measurements whilst keeping in perspective those results obtained at previous hadron colliders. The workshop has also debated some of the state-of-the-art theoretical considerations and the modeling of MPI in Monte Carlo event generators. The topics debated in the workshop included: Phenomenology of MPI processes and multiparton distributions; Considerations for the description of MPI in Quantum Chromodynamics (QCD); Measuring multiple partonic interactions; Experimental results on inelastic hadronic collisions: underlying event, minimum bias, forward energy flow; Monte Carlo generator development and tuning; Connections with low-x phenomena, diffractio...

  8. Accelerating Climate Simulations Through Hybrid Computing

    Science.gov (United States)

    Zhou, Shujia; Sinno, Scott; Cruz, Carlos; Purcell, Mark

    2009-01-01

    Unconventional multi-core processors (e.g., IBM Cell B/E and NYIDIDA GPU) have emerged as accelerators in climate simulation. However, climate models typically run on parallel computers with conventional processors (e.g., Intel and AMD) using MPI. Connecting accelerators to this architecture efficiently and easily becomes a critical issue. When using MPI for connection, we identified two challenges: (1) identical MPI implementation is required in both systems, and; (2) existing MPI code must be modified to accommodate the accelerators. In response, we have extended and deployed IBM Dynamic Application Virtualization (DAV) in a hybrid computing prototype system (one blade with two Intel quad-core processors, two IBM QS22 Cell blades, connected with Infiniband), allowing for seamlessly offloading compute-intensive functions to remote, heterogeneous accelerators in a scalable, load-balanced manner. Currently, a climate solar radiation model running with multiple MPI processes has been offloaded to multiple Cell blades with approx.10% network overhead.

  9. How Formal Dynamic Verification Tools Facilitate Novel Concurrency Visualizations

    Science.gov (United States)

    Aananthakrishnan, Sriram; Delisi, Michael; Vakkalanka, Sarvani; Vo, Anh; Gopalakrishnan, Ganesh; Kirby, Robert M.; Thakur, Rajeev

    With the exploding scale of concurrency, presenting valuable pieces of information collected by formal verification tools intuitively and graphically can greatly enhance concurrent system debugging. Traditional MPI program debuggers present trace views of MPI program executions. Such views are redundant, often containing equivalent traces that permute independent MPI calls. In our ISP formal dynamic verifier for MPI programs, we present a collection of alternate views made possible by the use of formal dynamic verification. Some of ISP’s views help pinpoint errors, some facilitate discerning errors by eliminating redundancy, while others help understand the program better by displaying concurrent even orderings that must be respected by all MPI implementations, in the form of completes-before graphs. In this paper, we describe ISP’s graphical user interface (GUI) capabilities in all these areas which are currently supported by a portable Java based GUI, a Microsoft Visual Studio GUI, and an Eclipse based GUI whose development is in progress.

  10. Multiphoton ionization of (Xe)/sub n/ and (NO)/sub n/ clusters using a picosecond laser

    International Nuclear Information System (INIS)

    Smith, D.B.; Miller, J.C.

    1989-01-01

    In an effort to extend the application of multiphoton ionization (MPI) spectroscopy to the study of weakly bound systems, we have begun a systematic investigation of picosecond MPI in van der Waals molecules and clusters. To our knowledge no previous picosecond MPI studies of weakly bound systems have been reported. We present here results of picosecond MPI of Xe/sub n/(n = 1-20) and (NO)/sub n/(n = 1-4) clusters. Previous MPI studies using nanosecond lasers have not detected the NO cluster series, presumably because of fast dissociation channels. The use of high peak-power allows resonant and non-resonant photon absorption to the ionization limit to compete effectively with fast dissociative processes. 10 refs., 2 figs

  11. A Convex Formulation for Magnetic Particle Imaging X-Space Reconstruction.

    Science.gov (United States)

    Konkle, Justin J; Goodwill, Patrick W; Hensley, Daniel W; Orendorff, Ryan D; Lustig, Michael; Conolly, Steven M

    2015-01-01

    Magnetic Particle Imaging (mpi) is an emerging imaging modality with exceptional promise for clinical applications in rapid angiography, cell therapy tracking, cancer imaging, and inflammation imaging. Recent publications have demonstrated quantitative mpi across rat sized fields of view with x-space reconstruction methods. Critical to any medical imaging technology is the reliability and accuracy of image reconstruction. Because the average value of the mpi signal is lost during direct-feedthrough signal filtering, mpi reconstruction algorithms must recover this zero-frequency value. Prior x-space mpi recovery techniques were limited to 1d approaches which could introduce artifacts when reconstructing a 3d image. In this paper, we formulate x-space reconstruction as a 3d convex optimization problem and apply robust a priori knowledge of image smoothness and non-negativity to reduce non-physical banding and haze artifacts. We conclude with a discussion of the powerful extensibility of the presented formulation for future applications.

  12. Spontaneous vesicle phase formation by pseudogemini surfactants in aqueous solutions.

    Science.gov (United States)

    Sun, Nan; Shi, Lijuan; Lu, Fei; Xie, Shuting; Zheng, Liqiang

    2014-08-14

    The phase behavior of a kind of pseudogemini surfactant in aqueous solutions, formed by the mixture of sodium dodecyl benzene sulfonate (SDBS) and butane-1,4-bis (methylimidazolium bromide) ([mim-C4-mim]Br2) or butane-1,4-bis(methylpyrrolidinium bromide) ([mpy-C4-mpy]Br2) in a molar ratio of 2 : 1, is reported in the present work. When [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 is mixed with SDBS in aqueous solutions, one cationic [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 molecule "bridges" two SDBS molecules by noncovalent interactions (e.g. electrostatic, π-π stacking, and σ-π interactions), behaving like a pseudogemini surfactant. Vesicles can be formed by this kind of pseudogemini surfactant, determined by freeze-fracture transmission electron microscopy (FF-TEM) or cryogenic-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). The mixed system of sodium dodecyl sulfate (SDS) with [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 was also constructed, and only micelles were observed. We infer that a pseudogemini surfactant is formed under the synergic effect of electrostatic, π-π stacking, and σ-π interactions in the SDBS/[mim-C4-mim]Br2/H2O system, while electrostatic attraction and hydrophobic interactions may provide the directional force for vesicle formation in the SDBS/[mpy-C4-mpy]Br2/H2O system.

  13. Increased accuracy of single photon emission computed tomography (SPECT myocardial perfusion scintigraphy using iterative reconstruction of images

    Directory of Open Access Journals (Sweden)

    Stević Miloš

    2016-01-01

    Full Text Available Background/Aim. Filtered back projection (FBP is a common way of processing myocardial perfusion imaging (MPI studies. There are artifacts in FBP which can cause falsepositive results. Iterative reconstruction (IR is developed to reduce false positive findings in MPI studies. The aim of this study was to evaluate the difference in the number of false positive findings in MPI studies, between FBP and IR processing. Methods. We examined 107 patients with angina pectoris with MPI and coronary angiography (CAG, 77 man and 30 woman, aged 32−82. MPI studies were processed with FBP and with IR. Positive finding at MPI was visualization of the perfusion defect. Positive finding at CAG was stenosis of coronary artery. Perfusion defect at MPI without coronary artery stenosis at CAG was considered like false positive. The results were statistically analyzed with bivariate correlation, and with one sample t-test. Results. There were 20.6% normal, and 79.4% pathologic findings at FBP, 30.8% normal and 69.2% pathologic with IR and 37.4% normal and 62.6% pathologic at CAG. FBP produced 19 false-positive findings, at IR 11 false positive findings. The correlation between FBP and CAG was 0.658 (p < 0.01 and between IR and CAG 0.784 (p < 0.01. The number of false positive findings at MPI with IR was significantly lower than at FBP (p < 0.01. Conclusion. Our study shows that IR processing MPI scintigraphy has less number of false positive findings, therefore it is our choice for processing MPI studies.

  14. Sensitivity and specificity of thallium-201 perfusion scintigrams under exercise in the diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Verani, M.S.; Marcus, M.L.; Razzak, M.A.; Ehrhardt, J.C.

    1978-01-01

    The specificity and sensitivity of thallium-201 myocardial perfusion imaging (MPI), under exercise, in patients with suspected coronary-obstructive disease was compared with graded exercise ECG tests (GTX) in patients with angiographically normal (N = 34) and obstructed (N = 48) coronary arteries. Of the 34 patients with normal coronaries, only one had a perfusion defect on the MPI (specificity 97%). Of the 48 patients with coronary obstructive disease (>50% obstruction of at least one coronary vessel), MPI was positive in 38 (sensitivity 79%). In contrast, the GTX had a specificity of 62% and sensitivity of 88% if nondiagnostic GTX tests are excluded. When the MPI and the GTX were used in combination, however, the sensitivity of detecting patients with coronary obstructive disease was increased to 94% (p < 0.01). The MPI was particularly useful in the evaluation of the 26 patients with nondiagnostic GTX. In this group, 24 of the 26 patients were correctly identified by the MPI with respect to the presence or absence of coronary-obstructive disease. In the 14 patients with a history of classical angina but with normal coronaries, the MPI was negative in 13 and positive in one, thus suggesting that in the majority of these patients transient transmural myocardial ischemia probably does not occur during exercise. The presence or absence of angiographically demonstrable coronary collateral vessels did not seem to influence the exercise MPI in patients with coronary-obstructive disease. Thus, although the MPI does not correctly identify all patients with either coronary-obstructive disease or normal coronary arteries, it is helpful in patients who have a nondiagnostic GTX. Furthermore, when used in combination with the GTX, the MPI significantly increases the likelihood that significant coronary-obstructive disease is present when both tests are positive, and that coronary disease is absent when both tests are negative

  15. Role of myocardial perfusion imaging in acute coronary syndrome

    International Nuclear Information System (INIS)

    Aleem, M.

    2007-01-01

    Full text: In the cardiac emergency department, a number of patients present with acute chest pain. In case of non diagnostic ECG and enzymes, accurately categorizing the patient in high and low probability is difficult. Aim of study was to evaluate the role of resting myocardial perfusion imaging (MPI) in patients with acute coronary syndrome (ACS) and then to compare the results with subsequent stress imaging. Material and Methods. A total of 34 patients were selected for the study, which were divided into three groups on the basis of respective probabilities of having ACS. This probability was decided on the basis of nature of chest pain, ECG findings, enzymes levels, and age and sex. Arbitrary score was given to patient's condition. This score ranged from 1 to 14. Patients with score between 1-6 were assigned low probability, from 7-10 were assigned intermediate probability and patients having score greater than 11 were placed in high probability groups. Patients in the low and intermediate probability groups were injected with Tc 99 m- MIBI within 6 hours of onset of chest pain and were undergone resting myocardial perfusion imaging (MPI) 3 to five hours after injection.. Imaging in high probability group was performed at discharge. Four weeks after the acute event all the patients underwent stress myocardial perfusion imaging. Results: All patients (100%) with low probability of ACS (n=10) showed negative resting scans. On stress MPI two patients (20%) showed new defects. Patient with high probability of ACS (n=12), all were positive 100% on resting MPI. On stress MPI, three showed (25%) no change from rest MPI, while nine patients (75%) showed augmentation of defects and four out of these nine patients (33%) also showed new perfusion defects. Patients with intermediate probability of ACS (n=12), three showed positive rest MPI (25%). On stress MPI out of these three cases, one showed (8%) no change from rest MPI and two showed (17%) augmentation of defect

  16. SPECT myocardial perfusion imaging. Long-term prognostic value in diabetic patients with and without coronary artery disease

    International Nuclear Information System (INIS)

    Koehli, M.; Monbaron, D.; Gaillard, R.C.; Ruiz, J.; Prior, J.O.; Bischof Delaloye, A.; Calcagni, M.L.; Fivaz-Arbane, M.; Stauffer, J.C.

    2006-01-01

    Aim: To determine the long-term prognostic value of SPECT myocardial perfusion imaging (MPI) for the occurrence of cardiovascular events in diabetic patients. Patients, methods: SPECT MPI of 210 consecutive Caucasian diabetic patients were analysed using Kaplan-Meier event-free survival curve and independent predictors were determined by Cox multivariate analyses. Results: Follow-up was complete in 200 (95%) patients with a median period of 3.0 years (0.8-5.0). The population was composed of 114 (57%) men, age 65 ± 10 years, 181 (90.5%) type 2 diabetes mellitus, 50 (25%) with a history of coronary artery disease (CAD) and 98 (49%) presenting chest pain prior to MPI. The prevalence of abnormal MPI was 58%. Patients with a normal MPI had neither cardiac death, nor myocardial infarction, independently of a history of coronary artery disease or chest pain. Among the independent predictors of cardiac death and myocardial infarction, the strongest was abnormal MPI (p 5-fold increase in cardiovascular events. This emphasizes the value of SPECT MPI in predicting and risk-stratifying cardiovascular events in diabetic patients. (orig.)

  17. Impact of chronic kidney disease and stress myocardial perfusion imaging as a predictor of cardiovascular events

    International Nuclear Information System (INIS)

    Furuhashi, Tatsuhiko; Joki, Nobuhiko; Hase, Hiroki; Masai, Hirofumi; Kunimasa, Taeko; Nakazato, Ryo; Fukuda, Hiroshi; Sugi, Kaoru; Moroi, Masao

    2011-01-01

    Stress myocardial perfusion imaging (MPI) is an established means of predicting cardiovascular events and is suitable in chronic kidney disease (CKD) patients. We aimed to evaluate the prognostic value of CKD parameters and an abnormal stress MPI for cardiovascular events. A total of 495 patients with suspected coronary artery disease (CAD) or history of CAD including 130 CKD patients not undergoing hemodialysis, underwent stress MPI (313 males, mean age 70 years) and were followed up for 14 months (mean period). CKD was defined as an estimated GFR of 2 and/or persistent proteinuria. Cardiovascular events were defined as sudden cardiac death, acute coronary syndrome and congestive heart failure requiring hospitalization. Cardiovascular events occurred in 41 (8.3%) patients. Multivariate Cox regression analysis indicated that CKD [hazard ratio (HR) =3.76, p<0.001] and a stress MPI summed difference score (SDS) of ≥2 (HR=3.78, p<0.001) were independent predictors of cardiovascular events; CKD plus abnormal stress MPI was also a strong predictor of cardiovascular events (non-CKD and SDS <2 vs. CKD and SDS ≥2, HR=15.9, p<0.001). Both CKD and myocardial ischemia detected by stress MPI are independent predictors for cardiovascular events. Coexistence of CKD and myocardial ischemia detected by stress MPI is more useful for short-term risk stratification of cardiovascular events. (author)

  18. Magnetic particle imaging: advancements and perspectives for real-time in vivo monitoring and image-guided therapy

    Science.gov (United States)

    Pablico-Lansigan, Michele H.; Situ, Shu F.; Samia, Anna Cristina S.

    2013-05-01

    Magnetic particle imaging (MPI) is an emerging biomedical imaging technology that allows the direct quantitative mapping of the spatial distribution of superparamagnetic iron oxide nanoparticles. MPI's increased sensitivity and short image acquisition times foster the creation of tomographic images with high temporal and spatial resolution. The contrast and sensitivity of MPI is envisioned to transcend those of other medical imaging modalities presently used, such as magnetic resonance imaging (MRI), X-ray scans, ultrasound, computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this review, we present an overview of the recent advances in the rapidly developing field of MPI. We begin with a basic introduction of the fundamentals of MPI, followed by some highlights over the past decade of the evolution of strategies and approaches used to improve this new imaging technique. We also examine the optimization of iron oxide nanoparticle tracers used for imaging, underscoring the importance of size homogeneity and surface engineering. Finally, we present some future research directions for MPI, emphasizing the novel and exciting opportunities that it offers as an important tool for real-time in vivo monitoring. All these opportunities and capabilities that MPI presents are now seen as potential breakthrough innovations in timely disease diagnosis, implant monitoring, and image-guided therapeutics.

  19. Multiphoton ionization of (Xe)n and (NO)n clusters using a picosecond laser

    International Nuclear Information System (INIS)

    Smith, D.B.; Miller, J.C.

    1989-01-01

    Mass-resolved multiphoton ionization (MPI) spectroscopy is an established technique for detecting and analyzing van der Waals molecules and larger clusters. MPI spectroscopy provides excellent detection sensitivity, moderately high resolution, and selectivity among cluster species. In addition to information provided by the analysis of photoions following MPI, photoelectron spectroscopy can reveal details regarding the structure of ionic states. Unfortunately, the technique is limited by its tendency to produce extensive fragmentation. Fragmentation is also a problem with other ionization techniques (e.g., electron impact ionization), but the intense laser beams required for MPI cause additional dissociation channels to become available. These channels include absorption of additional photons by parent ions (ion ladder mechanism), absorption of additional photons by fragment ions (ladder switching mechanism), and resonances with dissociative states in the neutral manifold. The existence of these dissociation channels can preclude the use of MPI spectroscopy in many situations. Recently, MPI studies of stable molecules using picosecond lasers (pulse length = 1 - 10 ps) have indicated that limitations due to fragmentation might be subdued. With picosecond lasers, dissociation mechanisms can be altered and in some cases fragmentation can be eliminated or reduced. Additional photon absorption competes effectively with dissociation channels when a very short laser pulse or, perhaps more importantly, a sufficiently high peak-power is used. In the case where ionic absorption and fragmentation occurs, it has been shown that picosecond MPI might favor the ion ladder mechanism rather than the ladder switching mechanism

  20. Multiscale Phase Inversion of Seismic Data

    KAUST Repository

    Fu, Lei

    2017-12-02

    We present a scheme for multiscale phase inversion (MPI) of seismic data that is less sensitive to the unmodeled physics of wave propagation and a poor starting model than standard full waveform inversion (FWI). To avoid cycle-skipping, the multiscale strategy temporally integrates the traces several times, i.e. high-order integration, to produce low-boost seismograms that are used as input data for the initial iterations of MPI. As the iterations proceed, higher frequencies in the data are boosted by using integrated traces of lower order as the input data. The input data are also filtered into different narrow frequency bands for the MPI implementation. At low frequencies, we show that MPI with windowed reflections approximates wave equation inversion of the reflection traveltimes, except no traveltime picking is needed. Numerical results with synthetic acoustic data show that MPI is more robust than conventional multiscale FWI when the initial model is far from the true model. Results from synthetic viscoacoustic and elastic data show that MPI is less sensitive than FWI to some of the unmodeled physics. Inversion of marine data shows that MPI is more robust and produces modestly more accurate results than FWI for this data set.

  1. Use of observation followed by outpatient stress testing in chest pain patients with prior coronary artery disease history: An evaluation of prognostic utility.

    Science.gov (United States)

    Khalil, Yasser; Schwartz, Melvin H; Pandey, Prasant S; Abdul Latif, Maida S; Matsumura, Martin E

    2015-06-01

    To determine the outcomes of patients with chest pain (CP) and prior history of coronary artery disease (CAD) managed with observation followed by outpatient stress myocardial perfusion imaging (MPI). Retrospective analysis of patients with CP managed with observation followed by outpatient stress MPI, comparing cardiovascular (CV) event rates stratified by CAD history. 375 patients were included: 111 with and 264 without a CAD history. All patients underwent outpatient stress MPI within 72 h of observation. MPI identified patients at risk for CV events. However, while patients with negative MPI and without a CAD history had very low rates of short- and long-term CAD events (0.8%, 0.8%, and 1.3% at 30 days, 1 year, and 3 years, respectively), event rates of those with a negative test but a CAD history were significantly higher (2.6%, 5.3%, and 6.6% at 30 days, 1 year and 3 years, respectively; p = 0.044 and p = 0.034 compared to CAD- patients at 1 year and 3 years, respectively). In a multivariable logistic regression model, a positive MPI proved to be an independent predictor of long-term CV events in patients with CP and prior CAD. Observation followed by stress MPI can effectively risk stratify CP patients with prior CAD for CV risk. These patients are at increased risk of CV events even after a low-risk stress MPI study. Patients presenting with CP and managed with a strategy of observation followed by a negative stress MPI warrant close short- and long-term monitoring for recurrent events.

  2. Performance comparison analysis library communication cluster system using merge sort

    Science.gov (United States)

    Wulandari, D. A. R.; Ramadhan, M. E.

    2018-04-01

    Begins by using a single processor, to increase the speed of computing time, the use of multi-processor was introduced. The second paradigm is known as parallel computing, example cluster. The cluster must have the communication potocol for processing, one of it is message passing Interface (MPI). MPI have many library, both of them OPENMPI and MPICH2. Performance of the cluster machine depend on suitable between performance characters of library communication and characters of the problem so this study aims to analyze the comparative performances libraries in handling parallel computing process. The case study in this research are MPICH2 and OpenMPI. This case research execute sorting’s problem to know the performance of cluster system. The sorting problem use mergesort method. The research method is by implementing OpenMPI and MPICH2 on a Linux-based cluster by using five computer virtual then analyze the performance of the system by different scenario tests and three parameters for to know the performance of MPICH2 and OpenMPI. These performances are execution time, speedup and efficiency. The results of this study showed that the addition of each data size makes OpenMPI and MPICH2 have an average speed-up and efficiency tend to increase but at a large data size decreases. increased data size doesn’t necessarily increased speed up and efficiency but only execution time example in 100000 data size. OpenMPI has a execution time greater than MPICH2 example in 1000 data size average execution time with MPICH2 is 0,009721 and OpenMPI is 0,003895 OpenMPI can customize communication needs.

  3. Iron oxide nanoparticle-micelles (ION-micelles for sensitive (molecular magnetic particle imaging and magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Lucas W E Starmans

    Full Text Available BACKGROUND: Iron oxide nanoparticles (IONs are a promising nanoplatform for contrast-enhanced MRI. Recently, magnetic particle imaging (MPI was introduced as a new imaging modality, which is able to directly visualize magnetic particles and could serve as a more sensitive and quantitative alternative to MRI. However, MPI requires magnetic particles with specific magnetic properties for optimal use. Current commercially available iron oxide formulations perform suboptimal in MPI, which is triggering research into optimized synthesis strategies. Most synthesis procedures aim at size control of iron oxide nanoparticles rather than control over the magnetic properties. In this study, we report on the synthesis, characterization and application of a novel ION platform for sensitive MPI and MRI. METHODS AND RESULTS: IONs were synthesized using a thermal-decomposition method and subsequently phase-transferred by encapsulation into lipidic micelles (ION-Micelles. Next, the material and magnetic properties of the ION-Micelles were analyzed. Most notably, vibrating sample magnetometry measurements showed that the effective magnetic core size of the IONs is 16 nm. In addition, magnetic particle spectrometry (MPS measurements were performed. MPS is essentially zero-dimensional MPI and therefore allows to probe the potential of iron oxide formulations for MPI. ION-Micelles induced up to 200 times higher signal in MPS measurements than commercially available iron oxide formulations (Endorem, Resovist and Sinerem and thus likely allow for significantly more sensitive MPI. In addition, the potential of the ION-Micelle platform for molecular MPI and MRI was showcased by MPS and MRI measurements of fibrin-binding peptide functionalized ION-Micelles (FibPep-ION-Micelles bound to blood clots. CONCLUSIONS: The presented data underlines the potential of the ION-Micelle nanoplatform for sensitive (molecular MPI and warrants further investigation of the Fib

  4. Low drive field amplitude for improved image resolution in magnetic particle imaging.

    Science.gov (United States)

    Croft, Laura R; Goodwill, Patrick W; Konkle, Justin J; Arami, Hamed; Price, Daniel A; Li, Ada X; Saritas, Emine U; Conolly, Steven M

    2016-01-01

    Magnetic particle imaging (MPI) is a new imaging technology that directly detects superparamagnetic iron oxide nanoparticles. The technique has potential medical applications in angiography, cell tracking, and cancer detection. In this paper, the authors explore how nanoparticle relaxation affects image resolution. Historically, researchers have analyzed nanoparticle behavior by studying the time constant of the nanoparticle physical rotation. In contrast, in this paper, the authors focus instead on how the time constant of nanoparticle rotation affects the final image resolution, and this reveals nonobvious conclusions for tailoring MPI imaging parameters for optimal spatial resolution. The authors first extend x-space systems theory to include nanoparticle relaxation. The authors then measure the spatial resolution and relative signal levels in an MPI relaxometer and a 3D MPI imager at multiple drive field amplitudes and frequencies. Finally, these image measurements are used to estimate relaxation times and nanoparticle phase lags. The authors demonstrate that spatial resolution, as measured by full-width at half-maximum, improves at lower drive field amplitudes. The authors further determine that relaxation in MPI can be approximated as a frequency-independent phase lag. These results enable the authors to accurately predict MPI resolution and sensitivity across a wide range of drive field amplitudes and frequencies. To balance resolution, signal-to-noise ratio, specific absorption rate, and magnetostimulation requirements, the drive field can be a low amplitude and high frequency. Continued research into how the MPI drive field affects relaxation and its adverse effects will be crucial for developing new nanoparticles tailored to the unique physics of MPI. Moreover, this theory informs researchers how to design scanning sequences to minimize relaxation-induced blurring for better spatial resolution or to exploit relaxation-induced blurring for MPI with

  5. Diagnostic value of 123I-betamethyl-p-iodophenyl-pentadecanoic acid (BMIPP) single photon emission computed tomography (SPECT) in patients with chest pain. Comparison with rest-stress 99mTc-tetrofosmin SPECT and coronary angiography

    International Nuclear Information System (INIS)

    Kawai, Yuko; Nozaki, Yoichi; Ohkusa, Takanori; Sakurai, Masayuki; Morita, Koichi; Tamaki, Nagara

    2004-01-01

    Basic and clinical studies have indicated that 15-(p-[ 123 I] iodophenyl)-3-(R, S) methylpentadecanoic acid (BMIPP) single photon emission computed tomography (SPECT) can identify ischemic myocardium without evidence of myocardial infarction by the regional decline of tracer uptake. The present study compared BMIPP SPECT with rest-stress myocardial perfusion imaging (MPI) findings and coronary angiography (CAG) in 150 patients with acute chest pain. Patients with acute chest pain who underwent all of the following tests were selected: MPI at rest-stress, BMIPP SPECT at rest and CAG. Organic coronary artery stenosis (≥75%) was observed in 46 patients, 27 patients had total or subtotal coronary occlusion by spasm in the spasm provocation test on CAG and the remaining 77 patients had no significant coronary artery stenosis or spasm. The sensitivity of BMIPP at rest to detect organic stenosis was significantly higher (54%) than that of rest-MPI (33%, p<0.005), but lower than that of stress-MPI (76%, p=0.05). The sensitivity of BMIPP at rest to detect spasm was significantly higher (63%) than that of both rest-MPI (15%; p<0.001) and stress-MPI (19%; p<0.001). Overall, the sensitivity of BMIPP at rest to detect both organic stenosis and spasm was significantly higher (58%) than that of rest-MPI (26%; p<0.001), despite having no significance with that of stress-MPI (55%). The specificity was not significantly different among the three imaging techniques. Resting BMIPP SPECT is an alternative method to stress MPI for identifying patients with not only organic stenosis but also spasm without the need for a stress examination. (author)

  6. Modified personal interviews: resurrecting reliable personal interviews for admissions?

    Science.gov (United States)

    Hanson, Mark D; Kulasegaram, Kulamakan Mahan; Woods, Nicole N; Fechtig, Lindsey; Anderson, Geoff

    2012-10-01

    Traditional admissions personal interviews provide flexible faculty-student interactions but are plagued by low inter-interview reliability. Axelson and Kreiter (2009) retrospectively showed that multiple independent sampling (MIS) may improve reliability of personal interviews; thus, the authors incorporated MIS into the admissions process for medical students applying to the University of Toronto's Leadership Education and Development Program (LEAD). They examined the reliability and resource demands of this modified personal interview (MPI) format. In 2010-2011, LEAD candidates submitted written applications, which were used to screen for participation in the MPI process. Selected candidates completed four brief (10-12 minutes) independent MPIs each with a different interviewer. The authors blueprinted MPI questions to (i.e., aligned them with) leadership attributes, and interviewers assessed candidates' eligibility on a five-point Likert-type scale. The authors analyzed inter-interview reliability using the generalizability theory. Sixteen candidates submitted applications; 10 proceeded to the MPI stage. Reliability of the written application components was 0.75. The MPI process had overall inter-interview reliability of 0.79. Correlation between the written application and MPI scores was 0.49. A decision study showed acceptable reliability of 0.74 with only three MPIs scored using one global rating. Furthermore, a traditional admissions interview format would take 66% more time than the MPI format. The MPI format, used during the LEAD admissions process, achieved high reliability with minimal faculty resources. The MPI format's reliability and effective resource use were possible through MIS and employment of expert interviewers. MPIs may be useful for other admissions tasks.

  7. Interval Changes in Myocardial Performance Index Predict Outcome in Severe Sepsis.

    Science.gov (United States)

    Nizamuddin, Junaid; Mahmood, Feroze; Tung, Avery; Mueller, Ariel; Brown, Samuel M; Shaefi, Shahzad; O'Connor, Michael; Talmor, Daniel; Shahul, Sajid

    2017-06-01

    Septic cardiomyopathy is a well-described consequence of septic shock and is associated with increased sepsis-related mortality. The myocardial performance index (MPI), a parameter derived from echocardiographic tissue Doppler measurements, allows for a more sensitive assessment of global cardiac function than do traditional metrics for cardiac function. The authors hypothesized that changes in left ventricular MPI in patients with severe sepsis would be associated with a higher 90-day mortality. Prospective, observational study. Intensive care units of a tertiary medical center. The study comprised 47 patients admitted with new diagnoses of severe sepsis or septic shock. All patients underwent transthoracic echocardiograms with assessment of MPI at enrollment and 24 hours later. Hemodynamic data and information on sepsis-related mortality were collected. In the primary analysis, the association between change in MPI from enrollment to 24 hours and sepsis-related 90-day mortality was assessed. Of the 47 patients enrolled, 30 demonstrated an improvement in MPI from 0 to 24 hours ("improved" group), and MPI worsened in the remaining 17 patients ("worsened" group). Despite no significant differences in ejection fraction or severity of illness, the median MPI at enrollment in the "improved" group was higher than baseline values in the "worsened" group (p = 0.005). A worsening MPI over the 24-hour study interval was associated with increased mortality at 90 days (p = 0.04), which remained significant (hazard ratio 3.72; 95% confidence interval 1.12-12.41; p = 0.03) after adjusting for severity of illness (Acute Physiology and Chronic Health Evaluation II score), intravenous fluids, and vasopressor use. In patients admitted to the intensive care unit with a diagnosis of severe sepsis or septic shock, a worsening MPI during the first 24 hours after intensive care unit admission was associated with higher 90-day mortality. Copyright © 2017 Elsevier Inc. All rights

  8. Parallel Monte Carlo simulations on an ARC-enabled computing grid

    International Nuclear Information System (INIS)

    Nilsen, Jon K; Samset, Bjørn H

    2011-01-01

    Grid computing opens new possibilities for running heavy Monte Carlo simulations of physical systems in parallel. The presentation gives an overview of GaMPI, a system for running an MPI-based random walker simulation on grid resources. Integrating the ARC middleware and the new storage system Chelonia with the Ganga grid job submission and control system, we show that MPI jobs can be run on a world-wide computing grid with good performance and promising scaling properties. Results for relatively communication-heavy Monte Carlo simulations run on multiple heterogeneous, ARC-enabled computing clusters in several countries are presented.

  9. A Principled Approach to Online Publication Listings and Scientific Resource Sharing

    Directory of Open Access Journals (Sweden)

    Jacquelijn Ringersma

    2010-03-01

    Full Text Available The Max Planck Institute (MPI for Psycholinguistics has developed a service to manage and present the scholarly output of their researchers. The PubMan database manages publication metadata and full-texts of publications published by their scholars. All relevant information regarding a researcher's work is brought together in this database, including supplementary materials and links to the MPI database for primary research data. The PubMan metadata is harvested into the MPI website CMS (Plone. The system developed for the creation of the publication lists, allows the researcher to create a selection of the harvested data in a variety of formats.

  10. Técnicas para cálculo distribuido de alto desempeño en mecánica computacional de fluidos

    OpenAIRE

    Dalcin, Lisandro Daniel

    2010-01-01

    Esta tesis describe el intento de facilitar el acceso a recursos de cálculo paralelo de alto rendimiento desde un entorno de programación basado en el lenguaje de programación Python. El resultado neto de este esfuerzo son dos paquetes de código abierto, MPI para Python (conocido en breve como mpi4py) y PETSc para Python (conocido en breve petsc4py). MPI para Python es proyecto de software que provee un enlace para la programación en Python con la especificación para paso de mensaje...

  11. Performance Evaluation of Supercomputers using HPCC and IMB Benchmarks

    Science.gov (United States)

    Saini, Subhash; Ciotti, Robert; Gunney, Brian T. N.; Spelce, Thomas E.; Koniges, Alice; Dossa, Don; Adamidis, Panagiotis; Rabenseifner, Rolf; Tiyyagura, Sunil R.; Mueller, Matthias; hide

    2006-01-01

    The HPC Challenge (HPCC) benchmark suite and the Intel MPI Benchmark (IMB) are used to compare and evaluate the combined performance of processor, memory subsystem and interconnect fabric of five leading supercomputers - SGI Altix BX2, Cray XI, Cray Opteron Cluster, Dell Xeon cluster, and NEC SX-8. These five systems use five different networks (SGI NUMALINK4, Cray network, Myrinet, InfiniBand, and NEC IXS). The complete set of HPCC benchmarks are run on each of these systems. Additionally, we present Intel MPI Benchmarks (IMB) results to study the performance of 11 MPI communication functions on these systems.

  12. Myocardial perfusion SPECT in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery

    International Nuclear Information System (INIS)

    Padma, Subramanyam; Sundaram, Palaniswamy Shanmuga

    2014-01-01

    Pediatric myocardial perfusion imaging (MPI) is not a routine investigation in an Indian setting due to under referrals and logistic problems. However, MPI is a frequently performed and established modality of investigation in adults for the identification of myocardial ischemia and viability. We report myocardial perfusion scintigraphy in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery. Adenosine stress MPI revealed a large infarct involving anterior segment with moderate reversible ischemia of the lateral left ventricular segment. Coronary angiogram later confirmed left main coronary artery ostial occlusion with retrograde collateral supply from dilated right coronary artery

  13. Applications of radionuclide myocardial perfusion imaging in acute coronary syndrome

    International Nuclear Information System (INIS)

    Han Pingping; Tian Yueqin

    2008-01-01

    In recent years, acute coronary syndrome(ACS) has been getting more and more attentions. Radionuclide myocardial perfusion imaging (MPI) can make a quick accurate diagnosis for patients with acute chest pain who cann't be diagnosed by conventional methods. The sensitivity and negative predictive value of MPI are relatively high. Besides, MPI can be applicated in the detection of ischemic and infarct size and degree, the risk stratification and the assessment of prognosis of the patients with ACS, and the appraisal of the effect of strategies. (authors)

  14. Cumulus cell mitochondrial activity in relation to body mass index in women undergoing assisted reproductive therapy

    Directory of Open Access Journals (Sweden)

    Victoria K. Gorshinova

    2017-06-01

    Full Text Available Most studies have considered the negative influence of obesity on fertility in both genders. In the present study, we assessed mitochondrial activity expressed as the mitochondrial potential index (MPI in cumulus cells from obese women and women with a normal body mass index (BMI during assisted reproductive therapy. The results revealed a significant reduction of MPI with increased body mass. The lower MPI levels in cumulus cells from obese women may reflect mitochondrial dysfunction caused by oxidative stress, which can affect the cumulus-oocyte complex and have an impact on oocyte development.

  15. Multiple Parton Interactions in p$bar{p}$ Collisions in D0 Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Golovanov, Georgy [Joint Inst. for Nuclear Research (JINR), Dubna (Russia)

    2016-01-01

    The thesis is devoted to the study of processes with multiple parton interactions (MPI) in a ppbar collision collected by D0 detector at the Fermilab Tevatron collider at sqrt(s) = 1.96 TeV. The study includes measurements of MPI event fraction and effective cross section, a process-independent parameter related to the effective interaction region inside the nucleon. The measurements are done using events with a photon and three hadronic jets in the final state. The measured effective cross section is used to estimate background from MPI for WH production at the Tevatron energy

  16. Clinical application of stress/rest myocardial perfusion imaging in the patients with 50%-75% coronary stenosis

    International Nuclear Information System (INIS)

    Han Pingping; Tian Yueqin; Fang Wei; Yang Minfu; Shen Rui; Wei Hongxing; Guo Xinhua; He Zuoxiang

    2011-01-01

    Objective: To evaluate the clinical application of stress/rest Mpi in the patients with 50%-75% coronary artery stenosis. Methods: The criteria for patient selection were that the patients should have at least one main coronary artery with stenosis more than 50%, and the maximal stenosis should be less than 75% according to Cage. The stress/rest Mpi was performed in 2 weeks before or after CAG. A total of 244 patients (178 males, 66 females) with mean age (57 ± 10) years were included in this study. Symptom restriction stress test was used and stress MPI was performed 1-1.5 h after 99 Tc m -MIBI (925 MBq) injection at the exercise peak. Rest MPI was performed within 48-72 h after stress MPI.Myocardial ischemia was diagnosed when there was a reduced uptake or even a defect in 2 different tomographic sections or in the same part of a myocardium in the continuous 2 slices. When there was an irreversible reduced uptake or defect, myocardial infarction was given as the final diagnosis. No reduced uptake or defect in all slices was shown as normal. The impact of MPI images on the selection for optimal clinical therapy plans was also discussed. χ 2 test was used for statistical analysis. Results: A total of 340 coronary arteries with stenosis 50%-75% were found by CAG. According to stress/rest MPI results, 207 patients (84.8%)presented normal, 33 had myocardial ischemia, 3 had myocardial infarction, and 1 had both myocardial infarction and ischemia. In abnormal MPI images, there were 61 ischemic segments and 9 infarct segments,which were associated with 43 stenotic arteries (23 LAD, 10 LCX, and 10 RCA). Patients were divided into 2 groups according to the results of MPI: Group 1 with normal MPI (207/244, 84.8%) and Group 2 with abnormal MPI (37/244, 15.2%). In Group 1, 9 patients underwent coronary artery revascularization (PTCA or CABG), and the others had medical treatment. Eight patients had PTCA and 29 patients had medical treatment in Group 2. There was a

  17. 99Tcm-tetrofosmin myocardial perfusion imaging for diagnosis of coronary heart disease

    International Nuclear Information System (INIS)

    Zhang Lele; Tian Wei; Shao Guoqiang; Zhang Hang; You Wei; Meng Qingle; Yang Rui; Cao Yan; Wang Xiaowen; Wang Feng

    2012-01-01

    Objective: To assess the clinical value of 99 Tc m -tetrofosmin (TF) MPI for diagnosis of CHD. Methods: A total of 73 patients (46 males,27 females; age: (61.16 ± 12.95) y) were included in this study. 99 Tc m -TF MPI and CAG were performed in all patients. Two-day protocol of MPI was used in this study, with rest MPI performed on the first day and stress (exercise stress or adenosine stress) imaging on the next day. CAG was performed within one week after MPI and served as the gold standard in diagnosis of CHD. Stenosis over 50% of the lumen was considered positive. The diagnostic efficacy of 99 Tc m -TF MPI was evaluated based on the results of CAG. Results: Among the 73 patients,43 patients were CAG positive, 27 cases with single vessel disease, 10 patients with double vessel disease and 6 patients with triple vessel disease. There were 37 patients with abnormality in MPI and 36 patients with normal MPI. Out of 43 patients with positive CAG, there were 32 cases diagnosed with myocardial ischemia and 11 with normal results in MPI. Among the 65 diseased vessels,there were 33 involved in LAD, 16 LCX and 16 RCA. The sensitivity,specificity, positive predictive value,negative predictive value and accuracy of MPI for detection of CHD were 74.4% (32/43), 83.3% (25/30), 86.5% (32/37), 69.4% (25/36) and 78.1% (57/73), respectively. The sensitivities for detection of single vessel disease, double vessel disease and triple vessel disease were 66.7% (18/27), 80.0% (8/10) and 5/6, respectively. The sensitivity and specificity of MPI for detection of coronary disease in all 219 vessels were 67.7% (44/65) and 89.0% (137/154), respectively. Conclusion: 99 Tc m -TF MPI, with convenient preparation and reliable properties of the tracer, may provide an alternative modality for accurate detection of CHD. (authors)

  18. Multiphoton ionization of H+2 at critical internuclear separations: non-Hermitian Floquet analysis

    International Nuclear Information System (INIS)

    Likhatov, P V; Telnov, D A

    2009-01-01

    We present ab initio time-dependent non-Hermitian Floquet calculations of multiphoton ionization (MPI) rates of hydrogen molecular ions subject to an intense linearly polarized monochromatic laser field with a wavelength of 800 nm. The orientation of the molecular axis is parallel to the polarization vector of the laser field. The MPI rates are computed for a wide range of internuclear separations R with high resolution in R and reproduce resonance and near-threshold structures. We show that enhancement of ionization at critical internuclear separations is related to resonance series with higher electronic states. The effect of two-centre interference on the MPI signal is discussed.

  19. Development and benchmark verification of a parallelized Monte Carlo burnup calculation program MCBMPI

    International Nuclear Information System (INIS)

    Yang Wankui; Liu Yaoguang; Ma Jimin; Yang Xin; Wang Guanbo

    2014-01-01

    MCBMPI, a parallelized burnup calculation program, was developed. The program is modularized. Neutron transport calculation module employs the parallelized MCNP5 program MCNP5MPI, and burnup calculation module employs ORIGEN2, with the MPI parallel zone decomposition strategy. The program system only consists of MCNP5MPI and an interface subroutine. The interface subroutine achieves three main functions, i.e. zone decomposition, nuclide transferring and decaying, data exchanging with MCNP5MPI. Also, the program was verified with the Pressurized Water Reactor (PWR) cell burnup benchmark, the results showed that it's capable to apply the program to burnup calculation of multiple zones, and the computation efficiency could be significantly improved with the development of computer hardware. (authors)

  20. Automatic performance tuning of parallel and accelerated seismic imaging kernels

    KAUST Repository

    Haberdar, Hakan; Siddiqui, Shahzeb; Feki, Saber

    2014-01-01

    the performance of the MPI communications as well as developer productivity by providing a higher level of abstraction. Keeping productivity in mind, we opted toward pragma based programming for accelerated computation on latest accelerated architectures

  1. 77 FR 50547 - Agency Information Collection: Emergency Submission for OMB Review (PACT: Clinical Innovation...

    Science.gov (United States)

    2012-08-21

    ... 10-0532h. j. Depression and Anxiety Stress Scales (DASS-21; Lovibond & Lovibond, 1995), VA Form 10... Pain Inventory (MPI; Kearns, Turk, & Rudy, 1985), VA Form 10-0532c. e. Pain Catastrophizing Scale...

  2. Summary of ATLAS Pythia 8 tunes

    CERN Document Server

    The ATLAS collaboration

    2012-01-01

    We summarize the latest ATLAS Pythia 8 minimum bias and underlying event tunes. The Pythia 8 MPI tunes in this note have been constructed for nine different PDFs, making use of a new x-dependent hadronic matter distribution model.

  3. Validation Study of CODES Dragonfly Network Model with Theta Cray XC System

    Energy Technology Data Exchange (ETDEWEB)

    Mubarak, Misbah [Argonne National Lab. (ANL), Argonne, IL (United States); Ross, Robert B. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-05-31

    This technical report describes the experiments performed to validate the MPI performance measurements reported by the CODES dragonfly network simulation with the Theta Cray XC system at the Argonne Leadership Computing Facility (ALCF).

  4. The Myocardial Performance Index During Low Dose Dobutamine Echocardiography in Normals and Patients With a Recent Myocardial Infarction

    DEFF Research Database (Denmark)

    Nørager, Betina; Husic, Mirza; Møller, Jacob E

    2004-01-01

    BACKGROUND: Wall-motion analysis during low-dose dobutamine echocardiography (LDDE) is a semiquantitative measure of left ventricular contractile reserve after myocardial infarction (MI). The Doppler echocardiographic myocardial performance index (MPI) is a quantitative measure of combined left...

  5. Parallel Monte Carlo simulation of aerosol dynamics

    KAUST Repository

    Zhou, K.; He, Z.; Xiao, M.; Zhang, Z.

    2014-01-01

    is simulated with a stochastic method (Marcus-Lushnikov stochastic process). Operator splitting techniques are used to synthesize the deterministic and stochastic parts in the algorithm. The algorithm is parallelized using the Message Passing Interface (MPI

  6. Master Veteran Index (MVI)

    Data.gov (United States)

    Department of Veterans Affairs — As of June 28, 2010, the Master Veteran Index (MVI) database based on the enhanced Master Patient Index (MPI) is the authoritative identity service within the VA,...

  7. Stampi: a message passing library for distributed parallel computing. User's guide

    International Nuclear Information System (INIS)

    Imamura, Toshiyuki; Koide, Hiroshi; Takemiya, Hiroshi

    1998-11-01

    A new message passing library, Stampi, has been developed to realize a computation with different kind of parallel computers arbitrarily and making MPI (Message Passing Interface) as an unique interface for communication. Stampi is based on MPI2 specification. It realizes dynamic process creation to different machines and communication between spawned one within the scope of MPI semantics. Vender implemented MPI as a closed system in one parallel machine and did not support both functions; process creation and communication to external machines. Stampi supports both functions and enables us distributed parallel computing. Currently Stampi has been implemented on COMPACS (COMplex PArallel Computer System) introduced in CCSE, five parallel computers and one graphic workstation, and any communication on them can be processed on. (author)

  8. Symmetries of the 2D magnetic particle imaging system matrix

    International Nuclear Information System (INIS)

    Weber, A; Knopp, T

    2015-01-01

    In magnetic particle imaging (MPI), the relation between the particle distribution and the measurement signal can be described by a linear system of equations. For 1D imaging, it can be shown that the system matrix can be expressed as a product of a convolution matrix and a Chebyshev transformation matrix. For multidimensional imaging, the structure of the MPI system matrix is not yet fully explored as the sampling trajectory complicates the physical model. It has been experimentally found that the MPI system matrix rows have symmetries and look similar to the tensor products of Chebyshev polynomials. In this work we will mathematically prove that the 2D MPI system matrix has symmetries that can be used for matrix compression. (paper)

  9. P-Refinement and P-Threads (Preprint)

    National Research Council Canada - National Science Library

    Dong, Steven; Karniadakis, George E

    2002-01-01

    ...]) in d dimensions, which is higher than lower-order methods. In this paper, we demonstrate that by employing multi-threading within MPI processes we manage to counter- balance the cost increase associated with P-refinement...

  10. Performance Impact of Rank-Reordering on Advanced Polar Decomposition Algorithms

    KAUST Repository

    Esposito, Aniello; Keyes, David E.; Ltaief, Hatem; Sukkari, Dalal

    2018-01-01

    We demonstrate the importance of both MPI rank reordering and choice of processor grid topology in the context of advanced dense linear algebra (DLA) applications for distributed-memory systems. In particular, we focus on the advanced polar

  11. 78 FR 65163 - Airworthiness Directives; Sikorsky Aircraft Corporation-Manufactured (Sikorsky) Model Helicopters...

    Science.gov (United States)

    2013-10-31

    ... reaching 1,450 hours TIS, whichever occurs later, perform a fluorescent-magnetic particle inspection (MPI...-destructive testing (NDT) UT Level I Special, Level II, or Level III inspector who is qualified under the...

  12. Architecture and method for a burst buffer using flash technology

    Science.gov (United States)

    Tzelnic, Percy; Faibish, Sorin; Gupta, Uday K.; Bent, John; Grider, Gary Alan; Chen, Hsing-bung

    2016-03-15

    A parallel supercomputing cluster includes compute nodes interconnected in a mesh of data links for executing an MPI job, and solid-state storage nodes each linked to a respective group of the compute nodes for receiving checkpoint data from the respective compute nodes, and magnetic disk storage linked to each of the solid-state storage nodes for asynchronous migration of the checkpoint data from the solid-state storage nodes to the magnetic disk storage. Each solid-state storage node presents a file system interface to the MPI job, and multiple MPI processes of the MPI job write the checkpoint data to a shared file in the solid-state storage in a strided fashion, and the solid-state storage node asynchronously migrates the checkpoint data from the shared file in the solid-state storage to the magnetic disk storage and writes the checkpoint data to the magnetic disk storage in a sequential fashion.

  13. Surface-enhanced Raman scattering on gold nanotrenches and nanoholes

    KAUST Repository

    Yue, Weisheng; Yang, Yang; Wang, Zhihong; Chen, Longqing; Wong, Ka Chun; Syed, Ahad A.; Chen, Zong; Wang, Xianbin

    2012-01-01

    Dependent effects on edge-to-edge distance and incidence polarization in surface-enhanced Raman Scattering (SERS) were studied in detection of 4-mercaptopyridine (4-MPy) molecules absorbed on gold nanotrenches and nanoholes. The gold nanostructures

  14. Multi parton interactions with CMS detector at LHC

    International Nuclear Information System (INIS)

    Ciangottini, D.

    2014-01-01

    Multi parton interactions (MPI) are experiencing a growing popularity and are widely invoked to account for observations that cannot be explained otherwise: the activity of the Underlying Event, the rates for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. The definition, implementation and tuning of MPI models in Monte Carlo generators plays an important role for the LHC physics: a better definition of the collision dynamics and a better definition of background processes. CMS was involved into the MPI characterization from the beginning of the LHC data-taken, starting from the Underlying Event measurements in Minimum Bias events. With the large integrated luminosity available, the Double Parton Scattering (DPS) measurements (2 hard events in the same proton-proton collision) can be performed in different final states and at different energy scales. The proposed contribution is intended to review past and ongoing studies on MPI with the CMS detector, providing a common interpretation.

  15. Concordance between myocardial perfusion scan assessed by SPECT and fractional flow reserve findings for detection of significant ischemia

    Directory of Open Access Journals (Sweden)

    Morteza Safi

    2016-09-01

    Conclusion: FFR and MPI with SPECT techniques showed significant concordance for detection of myocardial ischemia, regardless of the type of diseased coronary arteries. In this context, SPECT has high sensitivity and NPV for detection of ischemia compared with FFR.

  16. Porting the AVS/Express scientific visualization software to Cray XT4.

    Science.gov (United States)

    Leaver, George W; Turner, Martin J; Perrin, James S; Mummery, Paul M; Withers, Philip J

    2011-08-28

    Remote scientific visualization, where rendering services are provided by larger scale systems than are available on the desktop, is becoming increasingly important as dataset sizes increase beyond the capabilities of desktop workstations. Uptake of such services relies on access to suitable visualization applications and the ability to view the resulting visualization in a convenient form. We consider five rules from the e-Science community to meet these goals with the porting of a commercial visualization package to a large-scale system. The application uses message-passing interface (MPI) to distribute data among data processing and rendering processes. The use of MPI in such an interactive application is not compatible with restrictions imposed by the Cray system being considered. We present details, and performance analysis, of a new MPI proxy method that allows the application to run within the Cray environment yet still support MPI communication required by the application. Example use cases from materials science are considered.

  17. A platform independent communication library for distributed computing

    NARCIS (Netherlands)

    Groen, D.; Rieder, S.; Grosso, P.; de Laat, C.; Portegies Zwart, S.

    2010-01-01

    We present MPWide, a platform independent communication library for performing message passing between supercomputers. Our library couples several local MPI applications through a long distance network using, for example, optical links. The implementation is deliberately kept light-weight, platform

  18. Second International Workshop on Magnetic Particle Imaging

    CERN Document Server

    Borgert, Jörn; Magnetic Particle Imaging : A Novel SPIO Nanoparticle Imaging Technique

    2012-01-01

    Magnetic Particle Imaging (MPI) is a novel imaging modality. In MPI superparamagnetic iron oxide nanoparticles are used as tracer materials. The volume is the proceeding of the 2nd international workshop on magnetic particle imaging (IWMPI). The workshop aims at covering the status and recent developments of both, the instrumentation and the tracer material, as each of them is equally important in designing a well performing MPI. For instance, the current state of the art in magnetic coil design for MPI is discussed. With a new symmetrical arrangement of coils, a field-free line (FFL) can be produced that promises a significantly higher sensitivity compared with the standard arrangement for a FFP. Furthermore, the workshop aims at presenting results from phantom and pre-clinical studies.

  19. Do Multidimensional Pain Inventory scale score changes indicate risk of receiving sick leave benefits 1 year after a pain rehabilitation programme?

    DEFF Research Database (Denmark)

    Nyberg, Vanja E; Novo, Mehmed; Sjölund, Bengt H

    2011-01-01

    To study whether scale score changes in the Multidimensional Pain Inventory (MPI) can predict which persons disabled by pain will receive sick leave benefits 1 year after completing a pain rehabilitation programme.......To study whether scale score changes in the Multidimensional Pain Inventory (MPI) can predict which persons disabled by pain will receive sick leave benefits 1 year after completing a pain rehabilitation programme....

  20. Mannose Phosphate Isomerase Isoenzymes in Plutella xylostella Support Common Genetic Bases of Resistance to Bacillus thuringiensis Toxins in Lepidopteran Species

    OpenAIRE

    Herrero, Salvador; Ferré, Juan; Escriche, Baltasar

    2001-01-01

    A strong correlation between two mannose phosphate isomerase (MPI) isoenzymes and resistance to Cry1A toxins from Bacillus thuringiensis has been found in a Plutella xylostella population. MPI linkage to Cry1A resistance had previously been reported for a Heliothis virescens population. The fact that the two populations share similar biochemical, genetic, and cross-resistance profiles of resistance suggests the occurrence of homologous resistance loci in both species.

  1. High sensitivity tracer imaging of iron oxides using magnetic particle imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodwill, Patrick [University of California, Dept. of Bioengineering, Berkeley, CA (United States); Konkle, Justin; Lu, Kuan; Zheng, Bo [UC Berkeley (UCSF), Joint Graduate Group in Bioengineering, CA (United States); Conolly, Steven [University of California, Berkeley Bioengineering, Electrical Engineering, and Computer Science, CA (United States)

    2014-07-01

    Full text: Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the 'black blood' contrast generated by SPIOs in MRI due to increased T2 dephasing, SPIOs in MPI generate positive, 'bright blood' contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. (author)

  2. Cardiac risk stratification with myocardial perfusion imaging in potential renal-pancreas transplant recipients

    International Nuclear Information System (INIS)

    McCarthy, M.C.; Larcos, G.; Chapman, J.

    1998-01-01

    Full text: Combined renal/pancreas transplantation is used in patients with severe type-1 diabetes and renal failure. Many patients have asymptomatic coronary artery disease (CAD). Thus, myocardial perfusion imaging (MPI) is widely used for preoperative risk assessment, however, its value has recently been challenged. The purpose of this study was to determine the predictive value of MPI compared to coronary angiography and/or thirty day perioperative cardiac events (cardiac death, myocardial infarction and unstable angina). We reviewed the MPI in 132 patients that were referred for possible renal pancreas transplantation during the period between 1987 - June 1997. Fifty five patients were excluded because of: still awaiting transplantation (n=19) ongoing medical assessment (n=21), received kidney only transplant (n=6) or other factors (n=9). Thus, 77 patients form the basis of this report. Seventy one patients were transplanted, 5 had coronary angiography and one died before transplantation but with coronary anatomy defined at autopsy. All patients (39 male, 38 female; mean age 37 years) had Tl-201 or Tc-99m MIBI SPECT at Westmead (n=54) or elsewhere (n=23). Patients underwent MPI, a mean of 12.1 months before transplantation and a mean of 6 months before coronary angiography or autopsy. MPI was normal in 64 (83%) and abnormal in 13 (17%) patients. Of the abnormal MPI, 7 patients had CAD and one had unstable angina post-operatively (PPV = 8/13; 61%). One patient had a fixed defect post CABG but proceeded to transplant with-out event; the other 4 patients had normal coronary anatomy. Of the normal MPIs there were no transplant related cardiac events, but one patient required CABG >12 months post MPI and a further patient died >12 months post transplant and was shown to have CAD at autopsy (NPV=62/64;97%). In conclusion we have found an excellent NPV and an acceptable PPV for MPI in potential renal pancreas graft recipients

  3. High sensitivity tracer imaging of iron oxides using magnetic particle imaging

    International Nuclear Information System (INIS)

    Goodwill, Patrick; Konkle, Justin; Lu, Kuan; Zheng, Bo; Conolly, Steven

    2014-01-01

    Full text: Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the 'black blood' contrast generated by SPIOs in MRI due to increased T2 dephasing, SPIOs in MPI generate positive, 'bright blood' contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. (author)

  4. Combined use of 64-slice computed tomography angiography and gated myocardial perfusion SPECT for the detection of functionally relevant coronary artery stenoses. First results in a clinical setting concerning patients with stable angina

    International Nuclear Information System (INIS)

    Hacker, M.; Hack, N.; Tiling, R.; Jakobs, T.; Nikolaou, K.; Becker, C.; Ziegler, F. von; Knez, A.; Koenig, A.; Klauss, V.

    2007-01-01

    Aim: In patients with stable angina pectoris both morphological and functional information about the coronary artery tree should be present before revascularization therapy is performed. High accuracy was shown for spiral computed tomography (MDCT) angiography acquired with a 64-slice CT scanner compared to invasive coronary angiography (ICA) in detecting obstructive'' coronary artery disease (CAD). Gated myocardial SPECT (MPI) is an established method for the noninvasive assessment of functional significance of coronary stenoses. Aim of the study was to evaluate the combination of 64-slice CT angiography plus MPI in comparison to ICA plus MPI in the detection of hemodynamically relevant coronary artery stenoses in a clinical setting. Patients, methods: 30 patients (63 ± 10.8 years, 23 men) with stable angina (21 with suspected, 9 with known CAD) were investigated. MPI, 64-slice CT angiography and ICA were performed, reversible and fixed perfusion defects were allocated to determining lesions separately for MDCT angiography and ICA. The combination of MDCT angiography plus MPI was compared to the results of ICA plus MPI. Results: Sensitivity, specificity, negative and positive predictive value for the combination of MDCT angiography plus MPI was 85%, 97%, 98% and 79%, respectively, on a vessel-based and 93%, 87%, 93% and 88%, respectively, on a patient-based level. 19 coronary arteries with stenoses =50% in both ICA and MDCT angiography showed no ischemia in MPI. Conclusion: The combination of 64-slice CT angiography and gated myocardial SPECT enabled a comprehensive non-invasive view of the anatomical and functional status of the coronary artery tree. (orig.)

  5. Mild troponin I elevation does not predict ischemia on myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Le Dung Ha

    2017-08-01

    Full Text Available IntroductionData are limited on the degree of mild troponin I elevation and clinical risk factors in predicting myocardial ischemia.MethodsHospitalized adult patients who underwent myocardial perfusion imaging (MPI from 2015 to 2016 at Rochester General Hospital and had mild troponin I elevation (>0.1 and <1.5 ng/mL were included. Predictors of outcomes were determined using logistic regression model.ResultsOne hundred and sixty-six patients with mild troponin I elevation who underwent MPI were followed. Mean age was 69.6 ± 12.5 years and 53.0% of the patients were female. Fourteen patients (8.4% presented with typical chest pain (CP, 60 patients (36.1% had atypical CP and 92 patients (55.4% had no CP on presentation. MPI was positive for ischemia in 45 patients (27.1%. There was no difference in peak troponin I level with ischemia versus no ischemia on MPI (0.34 ng/dL [0.13-0.69] vs. 0.23 ng/dL [0.14-0.50], p value 0.254. Atypical CP did not predict the presence of ischemia on MPI (odds ratio [OR] 1.97, 95% confidence interval [CI] 0.91-4.26. Coronary artery disease (CAD history (age and sex adjusted p value 0.013, diabetes (adjusted p value 0.036, creatinine ≥2 mg/dL (adjusted p value 0.019 and dialysis (adjusted p value 0.006 were statistically significant predictors of ischemia on MPI.ConclusionsIn patients presenting with mild troponin I elevation, peak troponin I level did not predict ischemia on MPI. The presence of CAD history, diabetes, elevated creatinine and dialysis were predictors of ischemia on MPI.

  6. Comparison of Gated SPECT Myocardial Perfusion Imaging with Echocardiography for the Measurement of Left Ventricular Volumes and Ejection Fraction in Patients With Severe Heart Failure

    Science.gov (United States)

    Shojaeifard, Maryam; Ghaedian, Tahereh; Yaghoobi, Nahid; Malek, Hadi; Firoozabadi, Hasan; Bitarafan-Rajabi, Ahmad; Haghjoo, Majid; Amin, Ahmad; Azizian, Nasrin; Rastgou, Feridoon

    2015-01-01

    Background: Gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is known as a feasible tool for the measurement of left ventricular ejection fraction (EF) and volumes, which are of great importance in the management and follow-up of patients with coronary artery diseases. However, considering the technical shortcomings of SPECT in the presence of perfusion defect, the accuracy of this method in heart failure patients is still controversial. Objectives: The aim of the present study was to compare the results from gated SPECT MPI with those from echocardiography in heart failure patients to compare echocardiographically-derived left ventricular dimension and function data to those from gated SPECT MPI in heart failure patients. Patients and Methods: Forty-one patients with severely reduced left ventricular systolic function (EF ≤ 35%) who were referred for gated SPECT MPI were prospectively enrolled. Quantification of EF, end-diastolic volume (EDV), and end-systolic volume (ESV) was performed by using quantitative gated spect (QGS) (QGS, version 0.4, May 2009) and emory cardiac toolbox (ECTb) (ECTb, revision 1.0, copyright 2007) software packages. EF, EDV, and ESV were also measured with two-dimensional echocardiography within 3 days after MPI. Results: A good correlation was found between echocardiographically-derived EF, EDV, and ESV and the values derived using QGS (r = 0.67, r = 0.78, and r = 0.80 for EF, EDV, and ESV, respectively; P echocardiography. ECTb-derived EDV was also significantly higher than the EDV measured with echocardiography and QGS. The highest correlation between echocardiography and gated SPECT MPI was found for mean values of ESV different. Conclusions: Gated SPECT MPI has a good correlation with echocardiography for the measurement of left ventricular EF, EDV, and ESV in patients with severe heart failure. However, the absolute values of these functional parameters from echocardiography and gated

  7. Military Interoperable Digital Hospital Testbed

    Science.gov (United States)

    2012-07-01

    Subject outcome measures include blood pressure, waist circumference, weight, body mass index (BMI), body fat, HDL cholesterol, triglycerides , glucose ...master patient index (MPI), 625 duplicate chest x-rays and CT scans of the head between sending and receiving institution (taken within 0-7 days) were... Index (MPI) software. The report included chest x-rays (CPT 71010 and 71020) and CT scans of the head (CPT 70450) for the stated time periods. The

  8. Cardiac risk stratification with myocardial perfusion imaging in potential renal-pancreas transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, M.C.; Larcos, G.; Chapman, J. [Westmead Hospital, Westmead, Sydney, NSW (Australia). Departments of Nuclear Medicine and Ultrasound

    1998-06-01

    Full text: Combined renal/pancreas transplantation is used in patients with severe type-1 diabetes and renal failure. Many patients have asymptomatic coronary artery disease (CAD). Thus, myocardial perfusion imaging (MPI) is widely used for preoperative risk assessment, however, its value has recently been challenged. The purpose of this study was to determine the predictive value of MPI compared to coronary angiography and/or thirty day perioperative cardiac events (cardiac death, myocardial infarction and unstable angina). We reviewed the MPI in 132 patients that were referred for possible renal pancreas transplantation during the period between 1987 - June 1997. Fifty five patients were excluded because of: still awaiting transplantation (n=19) ongoing medical assessment (n=21), received kidney only transplant (n=6) or other factors (n=9). Thus, 77 patients form the basis of this report. Seventy one patients were transplanted, 5 had coronary angiography and one died before transplantation but with coronary anatomy defined at autopsy. All patients (39 male, 38 female; mean age 37 years) had Tl-201 or Tc-99m MIBI SPECT at Westmead (n=54) or elsewhere (n=23). Patients underwent MPI, a mean of 12.1 months before transplantation and a mean of 6 months before coronary angiography or autopsy. MPI was normal in 64 (83%) and abnormal in 13 (17%) patients. Of the abnormal MPI, 7 patients had CAD and one had unstable angina post-operatively (PPV = 8/13; 61%). One patient had a fixed defect post CABG but proceeded to transplant with-out event; the other 4 patients had normal coronary anatomy. Of the normal MPIs there were no transplant related cardiac events, but one patient required CABG >12 months post MPI and a further patient died >12 months post transplant and was shown to have CAD at autopsy (NPV=62/64;97%). In conclusion we have found an excellent NPV and an acceptable PPV for MPI in potential renal pancreas graft recipients

  9. Combined use of 64-slice computed tomography angiography and gated myocardial perfusion SPECT for the detection of functionally relevant coronary artery stenoses. First results in a clinical setting concerning patients with stable angina

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, M.; Hack, N.; Tiling, R. [Klinikum Grosshadern (Germany). Dept. of Nuclear Medicine; Jakobs, T.; Nikolaou, K.; Becker, C. [Klinikum Grosshadern (Germany). Dept. of Clinical Radiology; Ziegler, F. von; Knez, A. [Klinikum Grosshadern (Germany). Dept. of Cardiology; Koenig, A.; Klauss, V. [Medizinische Poliklinik-Innenstadt, Univ. of Munich (Germany). Dept. of Cardiology

    2007-07-01

    Aim: In patients with stable angina pectoris both morphological and functional information about the coronary artery tree should be present before revascularization therapy is performed. High accuracy was shown for spiral computed tomography (MDCT) angiography acquired with a 64-slice CT scanner compared to invasive coronary angiography (ICA) in detecting ''obstructive'' coronary artery disease (CAD). Gated myocardial SPECT (MPI) is an established method for the noninvasive assessment of functional significance of coronary stenoses. Aim of the study was to evaluate the combination of 64-slice CT angiography plus MPI in comparison to ICA plus MPI in the detection of hemodynamically relevant coronary artery stenoses in a clinical setting. Patients, methods: 30 patients (63 {+-} 10.8 years, 23 men) with stable angina (21 with suspected, 9 with known CAD) were investigated. MPI, 64-slice CT angiography and ICA were performed, reversible and fixed perfusion defects were allocated to determining lesions separately for MDCT angiography and ICA. The combination of MDCT angiography plus MPI was compared to the results of ICA plus MPI. Results: Sensitivity, specificity, negative and positive predictive value for the combination of MDCT angiography plus MPI was 85%, 97%, 98% and 79%, respectively, on a vessel-based and 93%, 87%, 93% and 88%, respectively, on a patient-based level. 19 coronary arteries with stenoses =50% in both ICA and MDCT angiography showed no ischemia in MPI. Conclusion: The combination of 64-slice CT angiography and gated myocardial SPECT enabled a comprehensive non-invasive view of the anatomical and functional status of the coronary artery tree. (orig.)

  10. Development and characterization of superparamagnetic coatings

    OpenAIRE

    Kuschnerus I.; Lüdtke-Buzug K.

    2015-01-01

    Since 2005, Magnetic Particle Imaging (MPI) is handled as a key technology with great potential in medical applications as an imaging method [1]. The superparamagnetic iron oxide nanoparticles (SPIONs) which are already used as a tracer in MPI, combined with various polymers, are being investigated in order to enhance this potential. A combination of polymers such as polyethylene (PE) and polyurethane (PU) and SPIONs could be used as a coating for medical devices, or added to semi-rigid polyu...

  11. Dual-frequency magnetic particle imaging of the Brownian particle contribution

    Energy Technology Data Exchange (ETDEWEB)

    Viereck, Thilo, E-mail: t.viereck@tu-bs.de; Kuhlmann, Christian; Draack, Sebastian; Schilling, Meinhard; Ludwig, Frank

    2017-04-01

    Magnetic particle imaging (MPI) is an emerging medical imaging modality based on the non-linear response of magnetic nanoparticles to an exciting magnetic field. MPI has been recognized as a fast imaging technique with high spatial resolution in the mm range. For some applications of MPI, especially in the field of functional imaging, the determination of the particle mobility (Brownian rotation) is of great interest, as it enables binding detection in MPI. It also enables quantitative imaging in the presence of Brownian-dominated particles, which is otherwise implausible. Discrimination of different particle responses in MPI is possible via the joint reconstruction approach. In this contribution, we propose a dual-frequency acquisition scheme to enhance sensitivity and contrast in the detection of different particle mobilities compared to a standard single-frequency MPI protocol. The method takes advantage of the fact, that the magnetization response of the tracer is strongly frequency-dependent, i.e. for low excitation frequencies a stronger Brownian contribution is observed.

  12. Correlation of chronic kidney disease, diabetes and peripheral artery disease with cardiovascular events in patients using stress myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Furuhashi, Tatsuhiko; Masai, Hirofumi; Kunimasa, Taeko; Nakazato, Ryo; Fukuda, Hiroshi; Sugi, Kaoru; Moroi, Masao

    2011-01-01

    Normal stress myocardial perfusion imaging (MPI) studies generally suggest an excellent prognosis for cardiovascular events. Chronic kidney disease (CKD), diabetes and peripheral artery disease (PAD) have been established as the risk factors for cardiovascular events. However, whether these risk factors significantly predict cardiovascular events in patients with normal stress MPI is unclear. The purpose of this study was to evaluate the prognostic value of these risk factors in patients with normal stress MPI. Patients with normal stress MPI (n=372, male=215 and female=157, age=69 years, CKD without hemodialysis=95, diabetes=99, PAD=19, previous coronary artery disease=116) were followed up for 14 months. Normal stress MPI was defined as a summed stress score of 2 and/or persistent proteinuria. Cardiovascular events included cardiac death, non-fatal myocardial infarction and congestive heart failure requiring hospitalization. Cardiovascular events occurred in 20 of 372 patients (5.4%). In univariate Cox regression analysis, PAD, diabetes, diabetic retinopathy, insulin use, anemia, hypoalbuminemia, CKD, left ventricular ejection fraction and pharmacological stress tests were significant predictors of cardiovascular events. In multivariate Cox regression analysis, PAD, diabetes and CKD were independent and significant predictors for cardiovascular events, and their number was the strongest predictor for cardiovascular events (hazard ratio=21.7, P<0.001). PAD, diabetes and CKD are coexisting, independent and significant risk factors for cardiovascular events, CKD being the strongest predictor. The number of coexisting risk factors is important in predicting cardiovascular events in patients with normal stress MPI. (author)

  13. [Three-dimensional finite element modeling and biomechanical simulation for evaluating and improving postoperative internal instrumentation of neck-thoracic vertebral tumor en bloc resection].

    Science.gov (United States)

    Qinghua, Zhao; Jipeng, Li; Yongxing, Zhang; He, Liang; Xuepeng, Wang; Peng, Yan; Xiaofeng, Wu

    2015-04-07

    To employ three-dimensional finite element modeling and biomechanical simulation for evaluating the stability and stress conduction of two postoperative internal fixed modeling-multilevel posterior instrumentation ( MPI) and MPI with anterior instrumentation (MPAI) with neck-thoracic vertebral tumor en bloc resection. Mimics software and computed tomography (CT) images were used to establish the three-dimensional (3D) model of vertebrae C5-T2 and simulated the C7 en bloc vertebral resection for MPI and MPAI modeling. Then the statistics and images were transmitted into the ANSYS finite element system and 20N distribution load (simulating body weight) and applied 1 N · m torque on neutral point for simulating vertebral displacement and stress conduction and distribution of motion mode, i. e. flexion, extension, bending and rotating. With a better stability, the displacement of two adjacent vertebral bodies of MPI and MPAI modeling was less than that of complete vertebral modeling. No significant differences existed between each other. But as for stress shielding effect reduction, MPI was slightly better than MPAI. From biomechanical point of view, two internal instrumentations with neck-thoracic tumor en bloc resection may achieve an excellent stability with no significant differences. But with better stress conduction, MPI is more advantageous in postoperative reconstruction.

  14. Development of training modules for magnetic particle inspection

    Science.gov (United States)

    Kosaka, Daigo; Eisenmann, David J.; Enyart, Darrel; Nakagawa, Norio; Lo, Chester; Orman, David

    2015-03-01

    Magnetic particle inspection (MPI) is a nondestructive evaluation technique used with ferromagnetic materials. Although the application of this method may appear straightforward, MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To fully appreciate industry specifications such as ASTM E-1444, users should develop a basic understanding of the many factors that are involved in MPI. We have developed a series of MPI training modules that are aimed at addressing this requirement. The modules not only offer qualitative explanations, but also show quantitative explanations in terms of measurement and numerical simulation data in many instances. There are five modules in all. Module ♯1 shows characteristics of waveforms and magnetizing methods. This allows MPI practitioners to make optimum choice of waveform and magnetizing method. Module ♯2 explains how material properties relate to the magnetic characteristics. Module ♯3 shows the strength of the excitation field or the flux leakage from a crack and how it compares to the detectability of a crack by MPI. Module ♯4 shows how specimen status may influence defect detection. Module ♯5 shows the effects of particle properties on defect detection.

  15. Corrosion resistance of rigid bonded magnet MQP-0 (NdFeB compound) pre and post surface coating

    International Nuclear Information System (INIS)

    Purwanto, Setyo; Ihsan, M.; Mujamilah; Mashadi

    2002-01-01

    Rigid Bonded Magnet (RBM) MQP-0 (NdFeB magnetics material compound) has been created and done some treatment. It has been known that corrosion resistance of RBM with epoxy resin binder is higher than RBM with polyester binder (PE). Corrosion rate in variety solutions like water. Na CI, H 2 SO 4 , has proved the earlier statement. For corrosion testing of RBM in Na CI solution with concentrations 0.05 M and 0.10 M shows corrosion rate 0.18 milli inches/year (mpy) and 2.93 mpy for epoxy binder, and 4.10 mpy and 24.87 mpy for polyester binder. In order to enhance the corrosion resistance, coating of RBM with epoxy resin has been done. And it has been known that coating of RBM with epoxy resin decrease of corrosion rate almost 50%. Corrosion rate of RBM with epoxy coating in 0.15 M Na CI is 9.38 mpy, compared without coating 15.11 mpy

  16. Geometry planning and image registration in magnetic particle imaging using bimodal fiducial markers

    International Nuclear Information System (INIS)

    Werner, F.; Hofmann, M.; Them, K.; Knopp, T.; Jung, C.; Salamon, J.; Kaul, M. G.; Mummert, T.; Adam, G.; Ittrich, H.; Werner, R.; Säring, D.; Weber, O. M.

    2016-01-01

    Purpose: Magnetic particle imaging (MPI) is a quantitative imaging modality that allows the distribution of superparamagnetic nanoparticles to be visualized. Compared to other imaging techniques like x-ray radiography, computed tomography (CT), and magnetic resonance imaging (MRI), MPI only provides a signal from the administered tracer, but no additional morphological information, which complicates geometry planning and the interpretation of MP images. The purpose of the authors’ study was to develop bimodal fiducial markers that can be visualized by MPI and MRI in order to create MP–MR fusion images. Methods: A certain arrangement of three bimodal fiducial markers was developed and used in a combined MRI/MPI phantom and also during in vivo experiments in order to investigate its suitability for geometry planning and image fusion. An algorithm for automated marker extraction in both MR and MP images and rigid registration was established. Results: The developed bimodal fiducial markers can be visualized by MRI and MPI and allow for geometry planning as well as automated registration and fusion of MR–MP images. Conclusions: To date, exact positioning of the object to be imaged within the field of view (FOV) and the assignment of reconstructed MPI signals to corresponding morphological regions has been difficult. The developed bimodal fiducial markers and the automated image registration algorithm help to overcome these difficulties.

  17. Evaluation of cardiac involvement using radionuclide myuocardial imaging in patients with Takayasu arteritis

    International Nuclear Information System (INIS)

    Yang Minfu; Guo Xinhua; He Zuoxiang; Jiang Xiongjing; Dou Kefei

    2008-01-01

    Objective: The aim of the study was to assess the value of radionuclide myocardial imaging in the evaluation of cardiac involvement in patients with Takayasu arteritis (TA). Methods: The 99 Tc m -methoxyisobutylisonitrile myocardial perlusion imaging (MIBI-MPI) and (or) 18 F-fluorodeoxyglucose (FDG) PET imaging findings in 12 TA patients [3 men and 9 women, mean age (35 ± 15) years] with coronary lesions (CL; n=8) or aortic insufficiency (AI; n=4) were retrospectively reviewed and analysed. Of the 4 AI-TA patients, 1 underwent exercise MIBI-MPI, 1 underwent pharmacologic stress MIBI-MPI and 2 un- derwent resting MIBI-MPI. Of the 8 CL-TA patients, 4 pnderwent MIBI-MPI (2 stress and 2 rest) and 4 un- derwent a dual-isotope simultaneous acquisition (DISA) SPECT protocol after injection of MIBI and FDG. Results: All 4 AI-TA patients showed left ventricular enlargement but no peffusion abnormalities. In 3 CL- TA patients with no documented infarct, MPI or DISA showed stress ischemia (n=2) or mismatched perfusion-metabolism defects (n=1). In the remaining 5 CL-TA patients with documented infarcts, 2 showed large perfusion defects on resting MIBI and 3 showed matched perfusion-metabolism defects on DISA SPECT. Conclusion: Radionuclide imaging is useful in providing a comprehensive functional evaluation for TA patients with cardiac involvement. (authors)

  18. Pengaruh Penambahan Inhibitor Alami terhadap Laju Korosi pada Material Pipa dalam Larutan Air Laut Buatan

    Directory of Open Access Journals (Sweden)

    Ardi Prasetia Yanuar

    2017-01-01

    Full Text Available Korosi merupakan penurunan mutu logam akibat adanya reaksi elektrokimia dengan lingkungannya. Banyak faktor yang dapat menyebabkan korosi suatu material, salah satu diantaranya yakni pengaruh konsentrasi media korosi. Ada banyak metode untuk menghambat proses terjadinya korosi. Salah satu diantara banyak metode yaitu penggunaan inhibitor. Inhibitor organik salah satu jenis inhibitor yang bersifat non-toksik, murah, sudah tersedia di alam, mudah diperbaharui dan tidak merusak lingkungan. Inhibitor organik tersebut diperoleh dengan mengekstrak beberapa bahan yang ada di alam. Dalam penetilitian ini inhibitor yang digunakan antara lain daun jambu biji, daun teh, kedelai dan kopi. Inhibitor tersebut digunakan pada material pipa baja dalam media air laut buatan yang memiliki kadar salinitas 35 ‰. Metode perhitungan laju korosi baja menggunakan metode weight loss dan electroplating. Laju korosi paling kecil yakni sebesar 3.10 mpy untuk API 5L dan 1.94 mpy untuk ASTM A53 dengan inhibitor daun teh. Inhibitor yang kurang maksimal dalam menghambat laju korosi yaitu inhibitor kopi yakni 6.12 mpy untuk API 5L dan 2.66 mpy untuk ASTM A53. Nilai laju korosi spesimen API 5L dan ASTM A53 yang tidak menggunakan inhibitor masing-masing 50.26 mpy dan 3.83 mpy. Inhibitor teh memiliki nilai effisiensi mencapai 93.83%. Sedangkan daun jambu biji memiliki nilai effisiensi mencapai 93.45%. Nilai effisiensi inhibitor kedelai mencapai 91.72% dan inhibitor kopi memiliki nilai effisiensi paling rendah hanya mencapai 87.83%.

  19. Multiphoton ionization in superintense, high-frequency laser fields. I. General developments

    International Nuclear Information System (INIS)

    Pont, M.

    1991-01-01

    This is the first of two papers studying multiphoton ionization (MPI) in superintense, high-frequency laser fields. They are based on a general iteration scheme in increasing powers of the inverse frequency. To lowest order in the frequency, i.e., the high-frequency limit, the atom was shown to be stable against decay by MPI, though distorted. To next order in the iteration, an expression for the MPI amplitude was obtained. In the present paper, we present general developments from this expression, valid for arbitrary polarization, binding potential, intensity, and initial state. First we analyze the symmetry of the angular distributions of photoelectrons determined by this expression for the MPI amplitude. This expression can explain the asymmetries in the angular distributions of photoelectrons occurring in the case of elliptic polarization that were recently reported in experiments. In the radiation regime where our theory applies these asymmetries are, however, weak. In certain instances our theory yields asymmetries in cases where lowest-order perturbation theory (LOPT) fails to predict them. We prove that at low intensities our expression for the MPI amplitude yields results in agreement with LOPT evaluated at high frequencies. An important part of this paper consists, however, of the derivation of an alternative form for the MPI amplitude of atomic hydrogen, which is substantially simpler, though somewhat less accurate. We study the consequences of this simplified expression for the case of linearly polarized fields in the following paper [Phys. Rev. A 44, xxxx (1991)

  20. CLOMP v1.5

    Energy Technology Data Exchange (ETDEWEB)

    Gyllenhaal, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-02-01

    CLOMP is the C version of the Livermore OpenMP benchmark developed to measure OpenMP overheads and other performance impacts due to threading. For simplicity, it does not use MPI by default but it is expected to be run on the resources a threaded MPI task would use (e.g., a portion of a shared memory compute node). Compiling with -DWITH_MPI allows packing one or more nodes with CLOMP tasks and having CLOMP report OpenMP performance for the slowest MPI task. On current systems, the strong scaling performance results for 4, 8, or 16 threads are of the most interest. Suggested weak scaling inputs are provided for evaluating future systems. Since MPI is often used to place at least one MPI task per coherence or NUMA domain, it is recommended to focus OpenMP runtime measurements on a subset of node hardware where it is most possible to have low OpenMP overheads (e.g., within one coherence domain or NUMA domain).

  1. Geometry planning and image registration in magnetic particle imaging using bimodal fiducial markers

    Energy Technology Data Exchange (ETDEWEB)

    Werner, F., E-mail: f.werner@uke.de; Hofmann, M.; Them, K.; Knopp, T. [Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany and Institute for Biomedical Imaging, Hamburg University of Technology, Hamburg 21073 (Germany); Jung, C.; Salamon, J.; Kaul, M. G.; Mummert, T.; Adam, G.; Ittrich, H. [Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg 20246 (Germany); Werner, R.; Säring, D. [Institute for Computational Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg 20246 (Germany); Weber, O. M. [Philips Medical Systems DMC GmbH, Hamburg 22335 (Germany)

    2016-06-15

    Purpose: Magnetic particle imaging (MPI) is a quantitative imaging modality that allows the distribution of superparamagnetic nanoparticles to be visualized. Compared to other imaging techniques like x-ray radiography, computed tomography (CT), and magnetic resonance imaging (MRI), MPI only provides a signal from the administered tracer, but no additional morphological information, which complicates geometry planning and the interpretation of MP images. The purpose of the authors’ study was to develop bimodal fiducial markers that can be visualized by MPI and MRI in order to create MP–MR fusion images. Methods: A certain arrangement of three bimodal fiducial markers was developed and used in a combined MRI/MPI phantom and also during in vivo experiments in order to investigate its suitability for geometry planning and image fusion. An algorithm for automated marker extraction in both MR and MP images and rigid registration was established. Results: The developed bimodal fiducial markers can be visualized by MRI and MPI and allow for geometry planning as well as automated registration and fusion of MR–MP images. Conclusions: To date, exact positioning of the object to be imaged within the field of view (FOV) and the assignment of reconstructed MPI signals to corresponding morphological regions has been difficult. The developed bimodal fiducial markers and the automated image registration algorithm help to overcome these difficulties.

  2. Optimization of Iron Oxide Tracer Synthesis for Magnetic Particle Imaging

    Directory of Open Access Journals (Sweden)

    Sabina Ziemian

    2018-03-01

    Full Text Available The optimization of iron oxide nanoparticles as tracers for magnetic particle imaging (MPI alongside the development of data acquisition equipment and image reconstruction techniques is crucial for the required improvements in image resolution and sensitivity of MPI scanners. We present a large-scale water-based synthesis of multicore superparamagnetic iron oxide nanoparticles stabilized with dextran (MC-SPIONs. We also demonstrate the preparation of single core superparamagnetic iron oxide nanoparticles in organic media, subsequently coated with a poly(ethylene glycol gallic acid polymer and phase transferred to water (SC-SPIONs. Our aim was to obtain long-term stable particles in aqueous media with high MPI performance. We found that the amplitude of the third harmonic measured by magnetic particle spectroscopy (MPS at 10 mT is 2.3- and 5.8-fold higher than Resovist for the MC-SPIONs and SC-SPIONs, respectively, revealing excellent MPI potential as compared to other reported MPI tracer particle preparations. We show that the reconstructed MPI images of phantoms using optimized multicore and specifically single-core particles are superior to that of commercially available Resovist, which we utilize as a reference standard, as predicted by MPS.

  3. The impact of chronic kidney disease as a predictor of major cardiac events in patients with no evidence of coronary artery disease

    International Nuclear Information System (INIS)

    Furuhashi, Tatsuhiko; Moroi, Masao; Joki, Nobuhiko; Hase, Hiroki; Masai, Hirofumi; Kunimasa, Taeko; Nakazato, Ryo; Fukuda, Hiroshi; Sugi, Kaoru

    2010-01-01

    Normal stress myocardial perfusion images (MPI) generally show good prognosis for cardiovascular events. However, chronic kidney disease (CKD) is one of the important risk factors for coronary artery disease (CAD), and the interpretation of normal stress MPI has not been well established in CKD patients with no evidence of CAD. The purpose of this study was to evaluate the long-term prognostic value of stress MPI in CKD patients with no evidence of myocardial ischemia or infarction. Patients who had no history but were suspected of CAD and had normal stress MPI (n=307, male=208, age=67 years, CKD/non-CKD=46/261) were followed-up for 4.5 years. CKD was defined as a glomerular filtration ratio of 2 and/or persistent proteinuria. Cardiac death, non-fatal myocardial infarction, and unstable angina requiring hospitalization were defined as major cardiac events. Major cardiac events were observed in 3 of 261 (1.1%) non-CKD patients and 6 of 46 (13%) CKD patients (p<0.001, with log-rank test). CKD was an independent risk factor for major cardiac events (hazard ratio=13.1, p<0.001, multivariate Cox regression analysis). Normal stress MPI does not always promise a good prognosis for major cardiac events. Even in patients with no evidence of CAD from stress MPI, CKD can be an independent and significant risk factor for major cardiac events. (author)

  4. Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Yuoness, Salem A.; Goha, Ahmed M.; Romsa, Jonathan G.; Akincioglu, Cigdem; Warrington, James C.; Datta, Sudip; Gambhir, Sanjay; Urbain, Jean-Luc C.; Vezina, William C. [London Health Sciences Centre, Department of Nuclear Medicine, London, ON (Canada); Massel, David R. [London Health Sciences Centre, Division of Cardiology, London, ON (Canada); Martell, Rafael [Private Practice, London, ON (Canada)

    2015-09-15

    Myocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results. A total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPI and 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization. Of these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 - 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain. A very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 - 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports

  5. Magnetic particle imaging: current developments and future directions

    Directory of Open Access Journals (Sweden)

    Panagiotopoulos N

    2015-04-01

    Full Text Available Nikolaos Panagiotopoulos,1 Robert L Duschka,1 Mandy Ahlborg,2 Gael Bringout,2 Christina Debbeler,2 Matthias Graeser,2 Christian Kaethner,2 Kerstin Lüdtke-Buzug,2 Hanne Medimagh,2 Jan Stelzner,2 Thorsten M Buzug,2 Jörg Barkhausen,1 Florian M Vogt,1 Julian Haegele1 1Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, 2Institute of Medical Engineering, University of Lübeck, Lübeck, Germany Abstract: Magnetic particle imaging (MPI is a novel imaging method that was first proposed by Gleich and Weizenecker in 2005. Applying static and dynamic magnetic fields, MPI exploits the unique characteristics of superparamagnetic iron oxide nanoparticles (SPIONs. The SPIONs’ response allows a three-dimensional visualization of their distribution in space with a superb contrast, a very high temporal and good spatial resolution. Essentially, it is the SPIONs’ superparamagnetic characteristics, the fact that they are magnetically saturable, and the harmonic composition of the SPIONs’ response that make MPI possible at all. As SPIONs are the essential element of MPI, the development of customized nanoparticles is pursued with the greatest effort by many groups. Their objective is the creation of a SPION or a conglomerate of particles that will feature a much higher MPI performance than nanoparticles currently available commercially. A particle’s MPI performance and suitability is characterized by parameters such as the strength of its MPI signal, its biocompatibility, or its pharmacokinetics. Some of the most important adjuster bolts to tune them are the particles’ iron core and hydrodynamic diameter, their anisotropy, the composition of the particles’ suspension, and their coating. As a three-dimensional, real-time imaging modality that is free of ionizing radiation, MPI appears ideally suited for applications such as vascular imaging and interventions as well as cellular and targeted imaging. A number

  6. Chronotropic response to vasodilator-stress in patients submitted to myocardial perfusion imaging: impact on the accuracy in detecting coronary stenosis

    International Nuclear Information System (INIS)

    Gimelli, Alessia; Coceani, Michele; Quaranta, Angela; Emdin, Michele; Liga, Riccardo; Marzullo, Paolo

    2015-01-01

    A lower heart rate response (HRR) during vasodilator MPI has been shown to have a relevant adverse prognostic impact. We sought to evaluate the interaction among individual HRR to vasodilator stress and myocardial perfusion imaging (MPI) accuracy in patients with suspected ischemic heart disease (IHD). One hundred and sixty-five consecutive patients were submitted to vasodilator-stress MPI on a cardiac camera equipped with cadmium-zinc-thelluride detectors and coronary angiography. A coronary stenosis >70 % was considered significant. In every patient, the summed difference score (SDS) was computed from MPI images. Patients were categorized according to the tertiles of the distribution of individual HRR during dipyridamole: ''Group 1'' (HRR < 8 bpm; lowest tertile); ''Group 2'' (8 ≤ HRR ≤ 12 bpm; middle tertile); ''Group 3'' (HRR >12 bpm; highest tertile). Significant coronary artery disease (CAD) was present in 102 (62 %) patients. In the overall population, MPI showed a significant accuracy (AUC: 0.81, 95 % CI 0.74-0.86; p < 0.001) in unmasking the presence of significant coronary stenosis. Interestingly, in patients with a blunted HRR during dipyridamole (''Group 1'') MPI showed a significantly lower sensitivity (68 %) in detecting CAD than in those with a higher HRR (''Group 3'') (91 %, p = 0.007), despite a preserved specificity (76 % vs 77 %, P=NS). Similarly, the correlation among CAD extent and post-stress LV functional stunning was limited to ''Group 3'' patients, while it disappeared in those with blunted HRR. In patients with suspected IHD, MPI sensitivity is strongly influenced by the magnitude of patient heart rate increase to the pharmacologic stressor, suggesting an interaction among blunted HRR and lower accuracy in unmasking CAD. (orig.)

  7. Thallium-201 myocardial perfusion imaging at rest and during exercise. Comparative sensitivity to electrocardiography in coronary artery disease

    International Nuclear Information System (INIS)

    Bailey, I.K.; Griffith, L.S.C.; Rouleau, J.; Strauss, H.W.; Pitt, B.

    1977-01-01

    The sensitivity of myocardial perfusion imaging (MPI) using thallium-201 injected both at rest and during peak exercise was compared to simultaneously recorded 12 lead electrocardiography (ECG) for the detection of transient ischemia in 20 normal subjects and 63 patients with coronary artery disease (CAD). No significant perfusion defects or ECG changes were seen on either the rest or exercise studies in any of the normal subjects. Fifty-six percent of patients with CAD developed new perfusion defects with exercise compared to 38 percent who developed ischemic ST-segment depression (P < 0.02). However, when chest pain and/or ST depression were considered indices of ischemia, the sensitivity of exercise testing and thallium-201 MPI was similar. The increased sensitivity of MPI compared to ST-segment depression on the ECG was due to patients with baseline ECG abnormalities and those who failed to achieve 85 percent of predicted maximum heart rate with exercise. Analysis of the exercise results according to the extent of coronary artery disease revealed a progressive increase in both positive ECGs and MPI with the number of vessels involved. In patients with single vessel disease the MPI was more sensitive than the ECG (P < 0.02). The combination of the rest and exercise ECG, MPI and chest pain during exercise failed to identify 11 percent of patients with CAD. Exercise thallium-201 MPI is a useful adjunct to conventional exercise testing particularly when evaluating patients with abnormal resting ECGs, those who develop ventricular conduction defects or arrhythmias during exercise, and those who fail to achieve their predicted heart rate because of fatigue or breathlessness

  8. Diagnostic accuracy of combined coronary angiography and adenosine stress myocardial perfusion imaging using 320-detector computed tomography: pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Nasis, Arthur; Ko, Brian S.; Leung, Michael C.; Antonis, Paul R.; Wong, Dennis T.; Kyi, Leo; Cameron, James D.; Meredith, Ian T.; Seneviratne, Sujith K. [Southern Health and Monash University, Monash Cardiovascular Research Centre, Monash Heart, Department of Medicine Monash Medical Centre (MMC), Melbourne (Australia); Nandurkar, Dee; Troupis, John M. [MMC, Southern Health, Department of Diagnostic Imaging, Melbourne (Australia)

    2013-07-15

    To determine the diagnostic accuracy of combined 320-detector row computed tomography coronary angiography (CTA) and adenosine stress CT myocardial perfusion imaging (CTP) in detecting perfusion abnormalities caused by obstructive coronary artery disease (CAD). Twenty patients with suspected CAD who underwent initial investigation with single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) were recruited and underwent prospectively-gated 320-detector CTA/CTP and invasive angiography. Two blinded cardiologists evaluated invasive angiography images quantitatively (QCA). A blinded nuclear physician analysed SPECT-MPI images for fixed and reversible perfusion defects. Two blinded cardiologists assessed CTA/CTP studies qualitatively. Vessels/territories with both >50 % stenosis on QCA and corresponding perfusion defect on SPECT-MPI were defined as ischaemic and formed the reference standard. All patients completed the CTA/CTP protocol with diagnostic image quality. Of 60 vessels/territories, 17 (28 %) were ischaemic according to QCA/SPECT-MPI criteria. Sensitivity, specificity, PPV, NPV and area under the ROC curve for CTA/CTP was 94 %, 98 %, 94 %, 98 % and 0.96 (P < 0.001) on a per-vessel/territory basis. Mean CTA/CTP radiation dose was 9.2 {+-} 7.4 mSv compared with 13.2 {+-} 2.2 mSv for SPECT-MPI (P < 0.001). Combined 320-detector CTA/CTP is accurate in identifying obstructive CAD causing perfusion abnormalities compared with combined QCA/SPECT-MPI, achieved with lower radiation dose than SPECT-MPI. (orig.)

  9. Diagnostic accuracy of combined coronary angiography and adenosine stress myocardial perfusion imaging using 320-detector computed tomography: pilot study

    International Nuclear Information System (INIS)

    Nasis, Arthur; Ko, Brian S.; Leung, Michael C.; Antonis, Paul R.; Wong, Dennis T.; Kyi, Leo; Cameron, James D.; Meredith, Ian T.; Seneviratne, Sujith K.; Nandurkar, Dee; Troupis, John M.

    2013-01-01

    To determine the diagnostic accuracy of combined 320-detector row computed tomography coronary angiography (CTA) and adenosine stress CT myocardial perfusion imaging (CTP) in detecting perfusion abnormalities caused by obstructive coronary artery disease (CAD). Twenty patients with suspected CAD who underwent initial investigation with single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) were recruited and underwent prospectively-gated 320-detector CTA/CTP and invasive angiography. Two blinded cardiologists evaluated invasive angiography images quantitatively (QCA). A blinded nuclear physician analysed SPECT-MPI images for fixed and reversible perfusion defects. Two blinded cardiologists assessed CTA/CTP studies qualitatively. Vessels/territories with both >50 % stenosis on QCA and corresponding perfusion defect on SPECT-MPI were defined as ischaemic and formed the reference standard. All patients completed the CTA/CTP protocol with diagnostic image quality. Of 60 vessels/territories, 17 (28 %) were ischaemic according to QCA/SPECT-MPI criteria. Sensitivity, specificity, PPV, NPV and area under the ROC curve for CTA/CTP was 94 %, 98 %, 94 %, 98 % and 0.96 (P < 0.001) on a per-vessel/territory basis. Mean CTA/CTP radiation dose was 9.2 ± 7.4 mSv compared with 13.2 ± 2.2 mSv for SPECT-MPI (P < 0.001). Combined 320-detector CTA/CTP is accurate in identifying obstructive CAD causing perfusion abnormalities compared with combined QCA/SPECT-MPI, achieved with lower radiation dose than SPECT-MPI. (orig.)

  10. Chronotropic response to vasodilator-stress in patients submitted to myocardial perfusion imaging: impact on the accuracy in detecting coronary stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Gimelli, Alessia; Coceani, Michele; Quaranta, Angela; Emdin, Michele [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Liga, Riccardo [University Hospital of Pisa, Cardio-Thoracic and Vascular Department, Pisa (Italy); Marzullo, Paolo [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); CNR, Institute of Clinical Physiology, Pisa (Italy)

    2015-11-15

    A lower heart rate response (HRR) during vasodilator MPI has been shown to have a relevant adverse prognostic impact. We sought to evaluate the interaction among individual HRR to vasodilator stress and myocardial perfusion imaging (MPI) accuracy in patients with suspected ischemic heart disease (IHD). One hundred and sixty-five consecutive patients were submitted to vasodilator-stress MPI on a cardiac camera equipped with cadmium-zinc-thelluride detectors and coronary angiography. A coronary stenosis >70 % was considered significant. In every patient, the summed difference score (SDS) was computed from MPI images. Patients were categorized according to the tertiles of the distribution of individual HRR during dipyridamole: ''Group 1'' (HRR < 8 bpm; lowest tertile); ''Group 2'' (8 ≤ HRR ≤ 12 bpm; middle tertile); ''Group 3'' (HRR >12 bpm; highest tertile). Significant coronary artery disease (CAD) was present in 102 (62 %) patients. In the overall population, MPI showed a significant accuracy (AUC: 0.81, 95 % CI 0.74-0.86; p < 0.001) in unmasking the presence of significant coronary stenosis. Interestingly, in patients with a blunted HRR during dipyridamole (''Group 1'') MPI showed a significantly lower sensitivity (68 %) in detecting CAD than in those with a higher HRR (''Group 3'') (91 %, p = 0.007), despite a preserved specificity (76 % vs 77 %, P=NS). Similarly, the correlation among CAD extent and post-stress LV functional stunning was limited to ''Group 3'' patients, while it disappeared in those with blunted HRR. In patients with suspected IHD, MPI sensitivity is strongly influenced by the magnitude of patient heart rate increase to the pharmacologic stressor, suggesting an interaction among blunted HRR and lower accuracy in unmasking CAD. (orig.)

  11. Theoretical predictions for spatially-focused heating of magnetic nanoparticles guided by magnetic particle imaging field gradients

    Energy Technology Data Exchange (ETDEWEB)

    Dhavalikar, Rohan [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Gainesville, FL 32611 (United States)

    2016-12-01

    Magnetic nanoparticles in alternating magnetic fields (AMFs) transfer some of the field's energy to their surroundings in the form of heat, a property that has attracted significant attention for use in cancer treatment through hyperthermia and in developing magnetic drug carriers that can be actuated to release their cargo externally using magnetic fields. To date, most work in this field has focused on the use of AMFs that actuate heat release by nanoparticles over large regions, without the ability to select specific nanoparticle-loaded regions for heating while leaving other nanoparticle-loaded regions unaffected. In parallel, magnetic particle imaging (MPI) has emerged as a promising approach to image the distribution of magnetic nanoparticle tracers in vivo, with sub-millimeter spatial resolution. The underlying principle in MPI is the application of a selection magnetic field gradient, which defines a small region of low bias field, superimposed with an AMF (of lower frequency and amplitude than those normally used to actuate heating by the nanoparticles) to obtain a signal which is proportional to the concentration of particles in the region of low bias field. Here we extend previous models for estimating the energy dissipation rates of magnetic nanoparticles in uniform AMFs to provide theoretical predictions of how the selection magnetic field gradient used in MPI can be used to selectively actuate heating by magnetic nanoparticles in the low bias field region of the selection magnetic field gradient. Theoretical predictions are given for the spatial decay in energy dissipation rate under magnetic field gradients representative of those that can be achieved with current MPI technology. These results underscore the potential of combining MPI and higher amplitude/frequency actuation AMFs to achieve selective magnetic fluid hyperthermia (MFH) guided by MPI. - Highlights: • SAR predictions based on a field-dependent magnetization relaxation model.

  12. LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

    International Nuclear Information System (INIS)

    Chen, Chun; Li, Dianfu; Miao, Changqing; Zhou, Yanli; Cao, Kejiang; Feng, Jianlin; Lloyd, Michael S.; Chen, Ji

    2012-01-01

    The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4 %) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p < 0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p < 0.01). Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI. (orig.)

  13. LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chun; Li, Dianfu; Miao, Changqing; Zhou, Yanli; Cao, Kejiang [First Affiliated Hospital of Nanjing Medical University, Department of Cardiology, Nanjing, Jiangsu (China); Feng, Jianlin [First Affiliated Hospital of Nanjing Medical University, Department of Nuclear Medicine, Nanjing, Jiangsu (China); Lloyd, Michael S. [Emory University School of Medicine, Division of Cardiology, Atlanta, GA (United States); Chen, Ji [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States)

    2012-07-15

    The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4 %) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p < 0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p < 0.01). Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI. (orig.)

  14. Magnetic particle imaging of blood coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Murase, Kenya, E-mail: murase@sahs.med.osaka-u.ac.jp; Song, Ruixiao; Hiratsuka, Samu [Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan)

    2014-06-23

    We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl{sub 2} to whole sheep blood mixed with magnetic nanoparticles (MNPs). The “MPI value” was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.

  15. A quantitative analysis of Tl-201 myocardial perfusion image with special reference to circumferential profile method

    International Nuclear Information System (INIS)

    Miyanaga, Hajime

    1982-01-01

    A quantitative analysis of thallium-201 myocardial perfusion image (MPI) was attempted by using circumferential profile method (CPM) and the first purpose of this study is to assess the clinical utility of this method for the detection of myocardial ischemia. In patients with coronary artery disease, CPM analysis to exercise T1-MPI showed high sensitivity (9/12, 75%) and specificity (9/9, 100%), whereas exercise ECG showed high sensitivity (9/12, 75%), but relatively low specificity (7/9, 78%). In patients with myocardial infarction, CPM also showed high sensitivity (34/38, 89%) for the detection of myocardial necrosis, compared with visual interpretation (31/38, 81%) and with ECG (31/38, 81%). Defect score was correlated well with the number of abnormal Q waves. In exercise study, CPM was also sensitive to the change of perfusion defect in T1-MPI produced by exercise. So the results indicate that CPM is a good method not only quantitatively but also objectively to analyze T1-MPI. Although ECG is the most commonly used diagnostic tool for ischemic heart disease, several exercise induced ischemic changes in ECG have been still on discussion as criteria. So the second purpose of this study is to evaluate these ischemic ECG changes by exercise T1-MPI analized quantitatively. ST depression (ischemic 1 mm and junctional 2 mm or more), ST elevation (1 mm or more), and coronary T wave reversion in exercise ECG were though to be ischemic changes. (J.P.N.)

  16. Enhancing Application Performance Using Mini-Apps: Comparison of Hybrid Parallel Programming Paradigms

    Science.gov (United States)

    Lawson, Gary; Sosonkina, Masha; Baurle, Robert; Hammond, Dana

    2017-01-01

    In many fields, real-world applications for High Performance Computing have already been developed. For these applications to stay up-to-date, new parallel strategies must be explored to yield the best performance; however, restructuring or modifying a real-world application may be daunting depending on the size of the code. In this case, a mini-app may be employed to quickly explore such options without modifying the entire code. In this work, several mini-apps have been created to enhance a real-world application performance, namely the VULCAN code for complex flow analysis developed at the NASA Langley Research Center. These mini-apps explore hybrid parallel programming paradigms with Message Passing Interface (MPI) for distributed memory access and either Shared MPI (SMPI) or OpenMP for shared memory accesses. Performance testing shows that MPI+SMPI yields the best execution performance, while requiring the largest number of code changes. A maximum speedup of 23 was measured for MPI+SMPI, but only 11 was measured for MPI+OpenMP.

  17. Hypoglycemia Is Independently Associated with Multidimensional Impairment in Elderly Diabetic Patients

    Directory of Open Access Journals (Sweden)

    A. Pilotto

    2014-01-01

    Full Text Available Aim. To identify the characteristics associated with multidimensional impairment, evaluated through the Multidimensional Prognostic Index (MPI, a validated predictive tool for mortality derived from a standardized Comprehensive Geriatric Assessment (CGA, in a cohort of elderly diabetic patients treated with oral hypoglycemic drugs. Methods and Results. The study population consisted of 1342 diabetic patients consecutively enrolled in 57 diabetes centers distributed throughout Italy, within the Metabolic Study. Inclusion criteria were diagnosis of type 2 diabetes mellitus (DM, 65 years old or over, and treatment with oral antidiabetic medications. Data concerning DM duration, medications for DM taken during the 3-month period before inclusion in the study, number of hypoglycemic events, and complications of DM were collected. Multidimensional impairment was assessed using the MPI evaluating functional, cognitive, and nutritional status; risk of pressure sores; comorbidity; number of drugs taken; and cohabitation status. The mean age of participants was 73.3 ± 5.5 years, and the mean MPI score was 0.22 ± 0.13. Multivariate analysis showed that advanced age, female gender, hypoglycemic events, and hospitalization for glycemic decompensation were independently associated with a worse MPI score. Conclusion. Stratification of elderly diabetic patients using the MPI might help to identify those patients at highest risk who need better-tailored treatment.

  18. Stampi: a message passing library for distributed parallel computing. User's guide, second edition

    International Nuclear Information System (INIS)

    Imamura, Toshiyuki; Koide, Hiroshi; Takemiya, Hiroshi

    2000-02-01

    A new message passing library, Stampi, has been developed to realize a computation with different kind of parallel computers arbitrarily and making MPI (Message Passing Interface) as an unique interface for communication. Stampi is based on the MPI2 specification, and it realizes dynamic process creation to different machines and communication between spawned one within the scope of MPI semantics. Main features of Stampi are summarized as follows: (i) an automatic switch function between external- and internal communications, (ii) a message routing/relaying with a routing module, (iii) a dynamic process creation, (iv) a support of two types of connection, Master/Slave and Client/Server, (v) a support of a communication with Java applets. Indeed vendors implemented MPI libraries as a closed system in one parallel machine or their systems, and did not support both functions; process creation and communication to external machines. Stampi supports both functions and enables us distributed parallel computing. Currently Stampi has been implemented on COMPACS (COMplex PArallel Computer System) introduced in CCSE, five parallel computers and one graphic workstation, moreover on eight kinds of parallel machines, totally fourteen systems. Stampi provides us MPI communication functionality on them. This report describes mainly the usage of Stampi. (author)

  19. Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women

    International Nuclear Information System (INIS)

    Li Jiangjin; Ma Shuren; Meng Tao; Bao Zhi; Cui Jianhe

    2011-01-01

    Objective: To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods: One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n=69)and exercise stress group (n=69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as 'gold standard' , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with χ 2 test or Fisher's exact test. Results: In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51), 72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); χ 2 =0.571, 0.714, 0.249, P>0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P=0.023. Conclusions: Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate. (authors)

  20. An efficient implementation of parallel molecular dynamics method on SMP cluster architecture

    International Nuclear Information System (INIS)

    Suzuki, Masaaki; Okuda, Hiroshi; Yagawa, Genki

    2003-01-01

    The authors have applied MPI/OpenMP hybrid parallel programming model to parallelize a molecular dynamics (MD) method on a symmetric multiprocessor (SMP) cluster architecture. In that architecture, it can be expected that the hybrid parallel programming model, which uses the message passing library such as MPI for inter-SMP node communication and the loop directive such as OpenMP for intra-SNP node parallelization, is the most effective one. In this study, the parallel performance of the hybrid style has been compared with that of conventional flat parallel programming style, which uses only MPI, both in cases the fast multipole method (FMM) is employed for computing long-distance interactions and that is not employed. The computer environments used here are Hitachi SR8000/MPP placed at the University of Tokyo. The results of calculation are as follows. Without FMM, the parallel efficiency using 16 SMP nodes (128 PEs) is: 90% with the hybrid style, 75% with the flat-MPI style for MD simulation with 33,402 atoms. With FMM, the parallel efficiency using 16 SMP nodes (128 PEs) is: 60% with the hybrid style, 48% with the flat-MPI style for MD simulation with 117,649 atoms. (author)

  1. Factors Associated with Male Partner Involvement in Programs for the Prevention of Mother-to-Child Transmission of HIV in Rural South Africa

    Directory of Open Access Journals (Sweden)

    Motlagabo G. Matseke

    2017-11-01

    Full Text Available Male partner involvement (MPI can contribute to the success of programs aimed at preventing mother-to-child transmission (PMTCT of HIV. However, the definition and measures of MPI differ according to context. This study utilized secondary cross-sectional data to investigate the prevalence and determinants of MPI among 463 male partners of HIV-infected pregnant women in rural South Africa. Results indicated that 44.1% of male partners reported involvement in most or all specified male partner involvement activities (i.e., scores of 7 to 9. Descriptive, correlation and multiple linear-regression analyses were conducted. Positive predictors of MPI included relationship status, own HIV status, awareness of female partner’s positive HIV status, female partner’s desire to have more children, having family planning discussions with provider, condom use to prevent HIV and sexually transmitted infections (STIs, and partner reasoning skills. Negative predictors included partner verbal aggression. Overall, although MPI is low, the study underlines important information that could be used to develop interventions aimed at improving maternal and infant health in PMTCT programs in South Africa.

  2. Hybrid cloud and cluster computing paradigms for life science applications.

    Science.gov (United States)

    Qiu, Judy; Ekanayake, Jaliya; Gunarathne, Thilina; Choi, Jong Youl; Bae, Seung-Hee; Li, Hui; Zhang, Bingjing; Wu, Tak-Lon; Ruan, Yang; Ekanayake, Saliya; Hughes, Adam; Fox, Geoffrey

    2010-12-21

    Clouds and MapReduce have shown themselves to be a broadly useful approach to scientific computing especially for parallel data intensive applications. However they have limited applicability to some areas such as data mining because MapReduce has poor performance on problems with an iterative structure present in the linear algebra that underlies much data analysis. Such problems can be run efficiently on clusters using MPI leading to a hybrid cloud and cluster environment. This motivates the design and implementation of an open source Iterative MapReduce system Twister. Comparisons of Amazon, Azure, and traditional Linux and Windows environments on common applications have shown encouraging performance and usability comparisons in several important non iterative cases. These are linked to MPI applications for final stages of the data analysis. Further we have released the open source Twister Iterative MapReduce and benchmarked it against basic MapReduce (Hadoop) and MPI in information retrieval and life sciences applications. The hybrid cloud (MapReduce) and cluster (MPI) approach offers an attractive production environment while Twister promises a uniform programming environment for many Life Sciences applications. We used commercial clouds Amazon and Azure and the NSF resource FutureGrid to perform detailed comparisons and evaluations of different approaches to data intensive computing. Several applications were developed in MPI, MapReduce and Twister in these different environments.

  3. Cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of the mannose 6-phosphate isomerase from Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Gowda, Giri; Sagurthi, Someswar Rao [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012 (India); Savithri, H. S. [Department of Biochemistry, Indian Institute of Science, Bangalore 560 012 (India); Murthy, M. R. N., E-mail: mrn@mbu.iisc.ernet.in [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012 (India)

    2008-02-01

    The cloning, expression, purification, crystallization and preliminary X-ray crystallographic studies of mannose 6-phosphate isomerase from S. typhimurium are reported. Mannose 6-phosphate isomerase (MPI; EC 5.3.1.8) catalyzes the reversible isomerization of d-mannose 6-phosphate (M6P) and d-fructose 6-phosphate (F6P). In the eukaryotes and prokaryotes investigated to date, the enzyme has been reported to play a crucial role in d-mannose metabolism and supply of the activated mannose donor guanosine diphosphate d-mannose (GDP-d-mannose). In the present study, MPI was cloned from Salmonella typhimurium, overexpressed in Escherichia coli and purified using Ni–NTA affinity column chromatography. Purified MPI crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 36.03, b = 92.2, c = 111.01 Å. A data set extending to 1.66 Å resolution was collected with 98.8% completeness using an image-plate detector system mounted on a rotating-anode X-ray generator. The asymmetric unit of the crystal cell was compatible with the presence of a monomer of MPI. A preliminary structure solution of the enzyme has been obtained by molecular replacement using Candida albicans MPI as the phasing model and the program Phaser. Further refinement and model building are in progress.

  4. Quantitative analysis of Tl-201 myocardial perfusion image with special reference to circumferential profile method

    Energy Technology Data Exchange (ETDEWEB)

    Miyanaga, Hajime [Kyoto Prefectural Univ. of Medicine (Japan)

    1982-08-01

    A quantitative analysis of thallium-201 myocardial perfusion image (MPI) was attempted by using circumferential profile method (CPM) and the first purpose of this study is to assess the clinical utility of this method for the detection of myocardial ischemia. In patients with coronary artery disease, CPM analysis to exercise T1-MPI showed high sensitivity (9/12, 75%) and specificity (9/9, 100%), whereas exercise ECG showed high sensitivity (9/12, 75%), but relatively low specificity (7/9, 78%). In patients with myocardial infarction, CPM also showed high sensitivity (34/38, 89%) for the detection of myocardial necrosis, compared with visual interpretation (31/38, 81%) and with ECG (31/38, 81%). Defect score was correlated well with the number of abnormal Q waves. In exercise study, CPM was also sensitive to the change of perfusion defect in T1-MPI produced by exercise. So the results indicate that CPM is a good method not only quantitatively but also objectively to analyze T1-MPI. Although ECG is the most commonly used diagnostic tool for ischemic heart disease, several exercise induced ischemic changes in ECG have been still on discussion as criteria. So the second purpose of this study is to evaluate these ischemic ECG changes by exercise T1-MPI analized quantitatively. ST depression (ischemic 1 mm and junctional 2 mm or more), ST elevation (1 mm or more), and coronary T wave reversion in exercise ECG were though to be ischemic changes.

  5. Enhanced Methods to Estimate the Efficiency of Magnetic Nanoparticles in Imaging

    Directory of Open Access Journals (Sweden)

    Ann M. Hirt

    2017-12-01

    Full Text Available Magnetic resonance imaging (MRI and magnetic particle imaging (MPI are powerful methods in the early diagnosis of diseases. Both imaging techniques utilize magnetic nanoparticles that have high magnetic susceptibility, strong saturation magnetization, and no coercivity. FeraSpinTM R and its fractionated products have been studied for their imaging performances; however, a detailed magnetic characterization in their immobilized state is still lacking. This is particularly important for applications in MPI that require fixation of magnetic nanoparticles with the target cells or tissues. We examine the magnetic properties of immobilized FeraSpinTM R, its size fractions, and Resovist®, and use the findings to demonstrate which magnetic properties best predict performance. All samples show some degree of oxidation to hematite, and magnetic interaction between the particles, which impact negatively on image performance of the materials. MRI and MPI performance show a linear dependency on the slope of the magnetization curve, i.e., initial susceptibility, and average blocking temperature. The best performance of particles in immobilized state for MPI is found for particle sizes close to the boundary between superparamagnetic (SP and magnetically ordered, in which only Néel relaxation is important. Initial susceptibility and bifurcation temperature are the best indicators to predict MRI and MPI performance.

  6. Relaxation-based viscosity mapping for magnetic particle imaging

    Science.gov (United States)

    Utkur, M.; Muslu, Y.; Saritas, E. U.

    2017-05-01

    Magnetic particle imaging (MPI) has been shown to provide remarkable contrast for imaging applications such as angiography, stem cell tracking, and cancer imaging. Recently, there is growing interest in the functional imaging capabilities of MPI, where ‘color MPI’ techniques have explored separating different nanoparticles, which could potentially be used to distinguish nanoparticles in different states or environments. Viscosity mapping is a promising functional imaging application for MPI, as increased viscosity levels in vivo have been associated with numerous diseases such as hypertension, atherosclerosis, and cancer. In this work, we propose a viscosity mapping technique for MPI through the estimation of the relaxation time constant of the nanoparticles. Importantly, the proposed time constant estimation scheme does not require any prior information regarding the nanoparticles. We validate this method with extensive experiments in an in-house magnetic particle spectroscopy (MPS) setup at four different frequencies (between 250 Hz and 10.8 kHz) and at three different field strengths (between 5 mT and 15 mT) for viscosities ranging between 0.89 mPa · s-15.33 mPa · s. Our results demonstrate the viscosity mapping ability of MPI in the biologically relevant viscosity range.

  7. Intake of Mung Bean Protein Isolate Reduces Plasma Triglyceride Level in Rats

    Directory of Open Access Journals (Sweden)

    Nobuhiko Tachibana

    2013-09-01

    Full Text Available ABSTRACTBackground: Mung bean is well known as a starch source, but the physiological effects of mung bean protein have received little attention. In this study, we isolated mung bean protein from de-starched mung bean solutions, and investigated its influence on lipid metabolism. Objective: The aim of this study is to clarify the influence of the lipid metabolism by consumption of mung bean protein isolate (MPIMethods: Diets containing either mung bean protein isolate (MPI or casein were fed to normal rats for 28 days.Results: Both groups ate the same amount of food, but the plasma triglyceride level, relative liver weight and liver lipid contents (cholesterol and triglyceride pool in the MPI group were significantly lower than in the casein group. In the MPI group, the expression of sterol regulatory-element binding factor 1 (SREBF1 mRNA in the liver was significantly different when compared with the casein group. The significantly lower levels of insulin and free fatty acids in the MPI-fed rats may be due to the regulation of genes related to lipid metabolism in the liver.Conclusions: These results suggest that MPI may improve the plasma lipid profile by normalizing insulin sensitivity.Keywords: mung bean, Vigna radiata L., 8S globulin, triglyceride, β-conglycinin, 7S globulin, insulin sensitivity, SREBF1

  8. Magnetic particle imaging: from proof of principle to preclinical applications

    Science.gov (United States)

    Knopp, T.; Gdaniec, N.; Möddel, M.

    2017-07-01

    Tomographic imaging has become a mandatory tool for the diagnosis of a majority of diseases in clinical routine. Since each method has its pros and cons, a variety of them is regularly used in clinics to satisfy all application needs. Magnetic particle imaging (MPI) is a relatively new tomographic imaging technique that images magnetic nanoparticles with a high spatiotemporal resolution in a quantitative way, and in turn is highly suited for vascular and targeted imaging. MPI was introduced in 2005 and now enters the preclinical research phase, where medical researchers get access to this new technology and exploit its potential under physiological conditions. Within this paper, we review the development of MPI since its introduction in 2005. Besides an in-depth description of the basic principles, we provide detailed discussions on imaging sequences, reconstruction algorithms, scanner instrumentation and potential medical applications.

  9. Review of progress in magnetic particle inspection

    Science.gov (United States)

    Eisenmann, David J.; Enyart, Darrel; Lo, Chester; Brasche, Lisa

    2014-02-01

    Magnetic particle inspection (MPI) has been widely utilized for decades, and sees considerable use in the aerospace industry with a majority of the steel parts being inspected with MPI at some point in the lifecycle. Typical aircraft locations inspected are landing gear, engine components, attachment hardware, and doors. In spite of its numerous applications the method remains poorly understood, and there are many aspects of that method which would benefit from in-depth study. This shortcoming is due to the fact that MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To promote understanding of the intricate method issues that affect sensitivity, or to assist with the revision of industry specifications and standards, research studies will be prioritized through the guidance of a panel of industry experts, using an approach which has worked successfully in the past to guide fluorescent penetrant inspection (FPI) research efforts.

  10. Multiple parton interactions at the LHC

    CERN Document Server

    Gaunt, Jonathan Richard

    2018-01-01

    Many high-energy collider experiments (including the current Large Hadron Collider at CERN) involve the collision of hadrons. Hadrons are composite particles consisting of partons (quarks and gluons), and this means that in any hadron–hadron collision there will typically be multiple collisions of the constituents — i.e. multiple parton interactions (MPI). Understanding the nature of the MPI is important in terms of searching for new physics in the products of the scatters, and also in its own right to gain a greater understanding of hadron structure. This book aims at providing a pedagogical introduction and a comprehensive review of different research lines linked by an involvement of MPI phenomena. It is written by pioneers as well as young leading scientists, and reviews both experimental findings and theoretical developments, discussing also the remaining open issues.

  11. Effect of small addition of aluminum on electrochemical corrosion behavior of magnesium-calcium sacrificial anode in underground environment

    International Nuclear Information System (INIS)

    Rizam, S.S.; Sasirehka, G.; Firdaus, A.M.H.; Mahdi, C.I.; Nazree, D.M.; Abdul Razak Daud; Azrem, A.A.

    2009-01-01

    The effect of small addition of Al on the electrochemical performances was investigated by open circuit potential and Tafel Extrapolation method. The results show that open circuit potential reveals as-cast Mg containing Ca alloys with minor content of Al maintained highly negative potential with the range of -1.68 to -1.63 V SCE in comparison to both pure Mg (-1.60V SCE ) and commercial high potential Mg content. Corrosion rate for the as-cast samples remains higher (30-17 mpy) than pure Mg (3 mpy) and commercial high potential Mg anode (14 mpy). The increasing small content of Al results in the reduction of corrosion rate significantly. Therefore, it proves that the performance of Mg containing Ca alloy is strongly influenced by the concentration of Al. (author)

  12. Aero-structural optimization of wind turbine blades using a reduced set of design load cases including turbulence

    DEFF Research Database (Denmark)

    Sessarego, Matias; Shen, Wen Zhong

    2018-01-01

    Modern wind turbine aero-structural blade design codes generally use a smaller fraction of the full design load base (DLB) or neglect turbulent inflow as defined by the International Electrotechnical Commission standards. The current article describes an automated blade design optimization method...... based on surrogate modeling that includes a very large number of design load cases (DLCs) including turbulence. In the present work, 325 DLCs representative of the full DLB are selected based on the message-passing-interface (MPI) limitations in Matlab. Other methods are currently being investigated, e.......g. a Python MPI implementation, to overcome the limitations in Matlab MPI and ultimately achieve a full DLB optimization framework. The reduced DLB and the annual energy production are computed using the state-of-the-art aero-servo-elastic tool HAWC2. Furthermore, some of the interior dimensions of the blade...

  13. Picosecond multiphoton ionization of atomic and molecular clusters

    International Nuclear Information System (INIS)

    Miller, J.C.; Smith, D.B.

    1990-01-01

    High peak-power picosecond laser pulses have been used for the first time to effect nonresonant or resonant multiphoton ionization (MPI) of clusters generated in a supersonic nozzle expansion. The resulting ions are subsequently detected and characterized by time-of-flight mass spectroscopy. Specifically, we present results involving MPI of clusters of xenon and nitric oxide. Previous MPI studies of many molecular clusters using nanosecond lasers have not been successful in observing the parent ion, presumably due to fast dissociation channels. It is proposed that the present technique is a new and rather general ionization source for cluster studies which is complementary to electron impact but may, in addition, provide unique spectroscopic or dynamical information. 23 refs., 5 figs

  14. The influence of hunger on meal to pellet intervals in barred owls

    Science.gov (United States)

    Duke, G.E.; Fuller, M.R.; Huberty, B.J.

    1980-01-01

    1. Barred owls fed at a sub-maintenance (SM) level had significantly (P < 0.01) longer meal to pellet intervals (MPI)/g eaten/kg body weight (BW) than those fed at an above maintenance (AM) level; MPI/g per kg for owls fed at a maintenance (M) level was intermediate but significantly (P < 0.01) different from both SM and AM.2. During SM feeding, MPI/g per kg gradually increased.3. The proportion of a meal occurring in a pellet was less in “hungry” owls whether losing weight (SM) or gaining (AM) as compared to owls maintaining their normal body weight (M).4. SM fed owls appear to be able to increase digestion time as well as thoroughness of digestion.

  15. Field performance of thirty mutant lines of the rice (Oryza sativa L.) varieties ICTA-Virginia and Precoz-ICTA

    International Nuclear Information System (INIS)

    Montepeque, R.; Molina, L. G.; Lopez, J. J.; Pazos, W.; Ramirez, J.

    1993-01-01

    Fifteen mutant lines from the variety ICTA-Virginia and fifteen from the variety Precozicta were evaluated according to their agronomic characteristics under conditions of the Motagua river valley during 1992. The objective was to select genotypes showing resistance to disease caused by Pyricularia grisea. The analysis of variance did not show significative differences among ICTA-Virginia mutants. The highest yield was form MV-860, 8.17 TM/ha and the lowest 5.31 TM/ha for MV-411. Significant differences were found among mutant lines from Precozicta. The highest yields were 6.06, 5.80 and 5.52 TM/ha for MPI-1189, MPI-1664 and MPI-1346 respectively. Inoculation with Pyricularia was made spraying it over the crop. However, it was not possible the evaluation of the disease in the neck (neck blast) due to absence of the pathogen. 5 tabs.(Author)

  16. Nuclear cardiology between echocardiography and coronary angiography in the management of CAD

    International Nuclear Information System (INIS)

    Anger, K.

    1996-01-01

    In managing coronary artery disease there are clearly posed questions: In diagnosis to assess presence, extent and severity of CAD, in therapy to assess prognosis and benefit of PTCA and ACVB. Coronary angiography remains the gold standard for assessing coronary stenosis, function imaging - stress echocardiography - and myocardial perfusion imaging (MIP) are assessing ischemia, i.e. extent and severity of CAD meaning prognosis and benefit of invasive therapy. The costs of echo /MPI/ catherization are 1 : 2: 6. When the essential conditions in non invasive investigations are observed - exact indication, maximal quality, evaluation of efficacy D, M and O - equal acceptance of all methods by cardiologists is attainable and there will be a great potential of cost saving in invasive diagnostics and therapy. The part of MPI is assessed in evaluating myocardium viability and benefit of invasive therapy, in the diagnosis of ischemia and evaluation of outcome MPI eventually will be replaced by stress echocardiography in future. (orig.) [de

  17. Effect of ionizing radiation on visco-elastic properties of polymethyl-methacrylate and poly-4-methylpentene-1

    International Nuclear Information System (INIS)

    Perepechko, I.I.; Mar'yasin, B.Ya.

    1978-01-01

    The effect of γ radiation on visco-elastic properties of polymethylmethacrylate (PMMA) and poly-4-methylpentene-1 (P4MPI) has been investigated by the method of the forced resonance oscillations of a cantilevered specimen. It has been shown, that the variation of the dynamic elasticity modulus of amorphous polymer when the irradiation dose increases, considerable depends on the polymer physical state during the measurement. The irradiated polymer is a binary mixture of radiolysis low-molecular products and polymer itself. The value of elasticity modulus in such a mixture is defined by the modules of different components. More complex than in PMMA in the effect of γ-radiation upon the P4MPI visco-elastic behaviour. During the P4MPI irradiation, the rebuilding of polymer supermolecular structure takes place, which results in the variation of the dynamic elasticity modulus values and in the intensity of peaks of mechanical losses

  18. Development and characterization of superparamagnetic coatings

    Directory of Open Access Journals (Sweden)

    Kuschnerus I.

    2015-09-01

    Full Text Available Since 2005, Magnetic Particle Imaging (MPI is handled as a key technology with great potential in medical applications as an imaging method [1]. The superparamagnetic iron oxide nanoparticles (SPIONs which are already used as a tracer in MPI, combined with various polymers, are being investigated in order to enhance this potential. A combination of polymers such as polyethylene (PE and polyurethane (PU and SPIONs could be used as a coating for medical devices, or added to semi-rigid polyurethane for the production of surgical instruments [2]. This would be of great interest, since the method provides high sensitivity with simultaneous high spatial resolution and three-dimensional imaging in real time. Therefore various superparamagnetic coatings were developed, tested and characterized. Finally SPIONs and various polymers were combined directly and used for MPI-compatible models.

  19. 8th International Workshop on Multiple Partonic Interactions at the LHC

    CERN Document Server

    2016-01-01

    MPI are experiencing a growing popularity and are widely invoked to account for observations that cannot be explained otherwise: the activity of the Underlying Event, the rates for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. At the same time, the implementation of MPI effects in Monte Carlo generators is quickly proceeding at an increasing level of sophistication and complexity, which can have far reaching implications for LHC physics. The ultimate ambition of this workshop is to promote MPI as a unifying concept between apparently distinct lines of research, to profit from experimental progress in order to constrain their implementation in models, and to evaluate their impact on the LHC physics program.

  20. Diagnostic value of thallium-201 myocardial perfusion IQ-SPECT without and with computed tomography-based attenuation correction to predict clinically significant and insignificant fractional flow reserve: A single-center prospective study.

    Science.gov (United States)

    Tanaka, Haruki; Takahashi, Teruyuki; Ohashi, Norihiko; Tanaka, Koichi; Okada, Takenori; Kihara, Yasuki

    2017-12-01

    The aim of this study was to clarify the predictive value of fractional flow reserve (FFR) determined by myocardial perfusion imaging (MPI) using thallium (Tl)-201 IQ-SPECT without and with computed tomography-based attenuation correction (CT-AC) for patients with stable coronary artery disease (CAD).We assessed 212 angiographically identified diseased vessels using adenosine-stress Tl-201 MPI-IQ-SPECT/CT in 84 consecutive, prospectively identified patients with stable CAD. We compared the FFR in 136 of the 212 diseased vessels using visual semiquantitative interpretations of corresponding territories on MPI-IQ-SPECT images without and with CT-AC.FFR inversely correlated most accurately with regional summed difference scores (rSDS) in images without and with CT-AC (r = -0.584 and r = -0.568, respectively, both P system can predict FFR at an optimal cut-off of reserved.

  1. Hybrid programming model for implicit PDE simulations on multicore architectures

    KAUST Repository

    Kaushik, Dinesh; Keyes, David E.; Balay, Satish; Smith, Barry F.

    2011-01-01

    The complexity of programming modern multicore processor based clusters is rapidly rising, with GPUs adding further demand for fine-grained parallelism. This paper analyzes the performance of the hybrid (MPI+OpenMP) programming model in the context of an implicit unstructured mesh CFD code. At the implementation level, the effects of cache locality, update management, work division, and synchronization frequency are studied. The hybrid model presents interesting algorithmic opportunities as well: the convergence of linear system solver is quicker than the pure MPI case since the parallel preconditioner stays stronger when hybrid model is used. This implies significant savings in the cost of communication and synchronization (explicit and implicit). Even though OpenMP based parallelism is easier to implement (with in a subdomain assigned to one MPI process for simplicity), getting good performance needs attention to data partitioning issues similar to those in the message-passing case. © 2011 Springer-Verlag.

  2. Feasibility and diagnostic power of transthoracic coronary Doppler for coronary flow velocity reserve in patients referred for myocardial perfusion imaging

    Directory of Open Access Journals (Sweden)

    Nylander Eva

    2008-03-01

    Full Text Available Abstract Background Myocardial perfusion imaging (MPI, using single photon emission computed tomography (SPECT is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Methods Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35–82, with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. Results We found that coronary flow velocity reserve (CFVR determined from diastolic measurements separated normal from abnormal MPI findings with statistical significance. TTDE identified coronary artery disease, defined from MPI, as reversible ischemia and/or permanent defect, with a sensitivity of 60% and a specificity of 79%. The positive predictive value was 43% and the negative predictive value was 88%. There was an overlap between groups which could be due to abnormal endothelial function in patients with normal myocardial perfusion having either hypertension or diabetes. Conclusion TTDE is an attractive non-invasive method to evaluate chest pain without the use of isotopes, but the diagnostic power is strongly dependent on the population investigated. Even in our heterogeneous clinical cardiac population, we found that CFVR>2 in the LAD excluded significant coronary artery disease detected by MPI.

  3. Myocardial Performance Index in Childhood Onset Essential Hypertension and White Coat Hypertension.

    Science.gov (United States)

    Gupta-Malhotra, Monesha; Hamzeh, Rabih K; Poffenbarger, Tim; McNiece-Redwine, Karen; Hashmi, Syed Shahrukh

    2016-03-01

    As a global measure of ventricular systolic and diastolic function, the myocardial performance index (MPI) can be an early indicator of hypertensive cardiomyopathy in children with essential hypertension (EH). Children with untreated newly diagnosed EH and white coat hypertension (WCH) by a 24-hour ambulatory blood pressure monitoring (ABPM), both groups without any identifiable etiology for the hypertension, were enrolled for the study. Echocardiograms and vascular ultrasounds for carotid artery intimal medial thickness were performed on all children prior to therapy. Diastolic function (peak E and A velocities, E/A ratio, isovolumic relaxation time, and deceleration times) and MPI were evaluated by simultaneous transmitral and transaortic spectral Doppler flow velocities. Systolic function was evaluated by shortening fraction and ejection fraction. A cohort of 66 children (24 with EH, 42 with WCH, males 61%, median age of 13 years, range 10-17 years) were enrolled in the study. The demographic, anthropometric, laboratory tests, vascular ultrasound, and conventional echocardiographic parameters were similar between the 2 groups. There was a very small difference in MPI between the EH and WCH children (0.28 SD: 0.07 vs. 0.31 SD: 0.08, P = 0.045). However, in EH children, MPI increased by 0.14 units for every 10 unit increase in mean ABPM systolic BP (95% confidence interval: 0.03-0.25). We found the increasing MPI was associated with increasing 24-hour mean systolic BP in children with EH. Therefore, MPI may have utility as a single, quick, noninvasive method of detection and tracking of subclinical hypertensive heart disease. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Detection of myocardial ischemia with myocardial perfusion SPECT in patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Seo, J. H.; Jeong, S. Y.; Bae, J. H.; Anh, B. C.; Lee, J.; Lee, K. B

    2004-01-01

    Diabetes mellitus(DM) is a critical disease associated with higher rates of cardiovascular morbidity and mortality. Atherosclerosis accounts for 65-80% of all deaths in diabetic patients and patients with DM are known to show high prevalence of coronary artery diseases(CAD). We evaluated the incidence of scintigraphic evidence of CAD in diabetic patients and results were compared with cardiovascular symptoms and clinical factors. 169 patients with DM(mean age 629years, 68 males) were referred for evaluation of CAD between Jan 2002 and Dec 2003. 101(60%) patients were with chest pain and 68(40%) were asymptomatic. Patients underwent exercise(n=6) or adenosine stress(n=163) SPECT myocardial perfusion imaging(MPI). Exclusion criteria included history of documented myocardial infarction, prior revascularization, clinically significant valvular heart disease, left-bundle branch block on rest ECG. We evaluated symptoms associated with cardiac problem and other clinical and laboratory data to reveal correlation with presence of CAD. MPI were assessed visually and semi-quantitatively with C-Equal program. Myocardial ischemia was detected in 52(31%) patients. Among them, 41 had 1-vessel and 9 had 2-vessel disease. In 52 patients with ischemia, 28(54%) were male and 24(46%) were female. 20/68(29%) asymptomatic and 32/101(32%) symptomatic patients had ischemia. Higher prevalence of neuropathy, hypertension, higher blood glucose level, HbA1c and CRP was noted in patients with myocardial ischemia. Serum levels of cholesterol and LDL was not significantly different between patients with ischemia and with normal MPI findings. Abnormal MPI findings were not related with gender and age. These results show a high prevalence of abnormal MPI results in diabetic patients regardless of symptoms. Screening stress MPI in diabetic patients should be indicated irrespective of symptoms, especially in patients with neuropathy, hypertension, higher level of blood glucose, or increased CRP

  5. Detection of myocardial ischemia with myocardial perfusion SPECT in patients with diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Seo, J. H.; Jeong, S. Y.; Bae, J. H.; Anh, B. C.; Lee, J.; Lee, K. B [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2004-07-01

    Diabetes mellitus(DM) is a critical disease associated with higher rates of cardiovascular morbidity and mortality. Atherosclerosis accounts for 65-80% of all deaths in diabetic patients and patients with DM are known to show high prevalence of coronary artery diseases(CAD). We evaluated the incidence of scintigraphic evidence of CAD in diabetic patients and results were compared with cardiovascular symptoms and clinical factors. 169 patients with DM(mean age 629years, 68 males) were referred for evaluation of CAD between Jan 2002 and Dec 2003. 101(60%) patients were with chest pain and 68(40%) were asymptomatic. Patients underwent exercise(n=6) or adenosine stress(n=163) SPECT myocardial perfusion imaging(MPI). Exclusion criteria included history of documented myocardial infarction, prior revascularization, clinically significant valvular heart disease, left-bundle branch block on rest ECG. We evaluated symptoms associated with cardiac problem and other clinical and laboratory data to reveal correlation with presence of CAD. MPI were assessed visually and semi-quantitatively with C-Equal program. Myocardial ischemia was detected in 52(31%) patients. Among them, 41 had 1-vessel and 9 had 2-vessel disease. In 52 patients with ischemia, 28(54%) were male and 24(46%) were female. 20/68(29%) asymptomatic and 32/101(32%) symptomatic patients had ischemia. Higher prevalence of neuropathy, hypertension, higher blood glucose level, HbA1c and CRP was noted in patients with myocardial ischemia. Serum levels of cholesterol and LDL was not significantly different between patients with ischemia and with normal MPI findings. Abnormal MPI findings were not related with gender and age. These results show a high prevalence of abnormal MPI results in diabetic patients regardless of symptoms. Screening stress MPI in diabetic patients should be indicated irrespective of symptoms, especially in patients with neuropathy, hypertension, higher level of blood glucose, or increased CRP.

  6. The role of pharmacological stress Tc-99m sestamibi myocardial perfusion imaging in an Australian population

    International Nuclear Information System (INIS)

    Howarth, D.M.; Booker, J.A.; Tan, T.S.K.; Bellamy, G.R.; Hardy, D.B.; Howarth, G.C.

    2003-01-01

    This observational study was performed in order to assess the exercise-related incremental diagnostic accuracy of Tc-99m sestamibi myocardial perfusion imaging (MPI) in a hospital-based Australian population, and to assess the relative roles of exercise and pharmacological stress in myocardial perfusion imaging (MPI). Two hundred and eight adult patients who had both Tc-99m sestamibi myocardial perfusion imaging and coronary angiography within a median time of 16 weeks were studied. The diagnostic end-point was coronary artery lesions of ≥50% and >70% stenosis detected on angiography. Using receiver operating characteristic curve analysis, the overall diagnostic accuracy was calculated, as well as the comparative accuracies in patients who undertook various levels of exercise stress testing (n=130) and those who received pharmacological (dipyridamole) stress testing (n=78). The overall respective diagnostic accuracy of Tc-99m sestamibi MPI for the diagnosis of coronary artery disease (>70% stenosis) was 81% and 76% when using the diagnostic criterion of ≥50% stenosis. On direct comparison of perfusion defects with angiographic stenoses, the respective sensitivity and specificity for the detection of >70% stenosis in each coronary artery territory was 73% and 79%. Pharmacological MPI showed a significantly greater sensitivity for the detection of localised stenoses compared to the overall group who had exercise MPI performed. Consequently, exercise stress MPI showed significantly more false negative lesions compared to dipyridamole stress imaging (p<0.003). However, a large proportion of patients were unable to perform to adequate exercise levels in this patient sample. We conclude that Tc-99m sestamibi myocardial perfusion imaging is an accurate non-invasive test for the diagnosis of coronary artery disease. Where any doubt exists as to the patient's ability to achieve exercise levels at or above 85% of the predicted value for age and gender, pharmacological

  7. Asynchronous Task-Based Parallelization of Algebraic Multigrid

    KAUST Repository

    AlOnazi, Amani A.

    2017-06-23

    As processor clock rates become more dynamic and workloads become more adaptive, the vulnerability to global synchronization that already complicates programming for performance in today\\'s petascale environment will be exacerbated. Algebraic multigrid (AMG), the solver of choice in many large-scale PDE-based simulations, scales well in the weak sense, with fixed problem size per node, on tightly coupled systems when loads are well balanced and core performance is reliable. However, its strong scaling to many cores within a node is challenging. Reducing synchronization and increasing concurrency are vital adaptations of AMG to hybrid architectures. Recent communication-reducing improvements to classical additive AMG by Vassilevski and Yang improve concurrency and increase communication-computation overlap, while retaining convergence properties close to those of standard multiplicative AMG, but remain bulk synchronous.We extend the Vassilevski and Yang additive AMG to asynchronous task-based parallelism using a hybrid MPI+OmpSs (from the Barcelona Supercomputer Center) within a node, along with MPI for internode communications. We implement a tiling approach to decompose the grid hierarchy into parallel units within task containers. We compare against the MPI-only BoomerAMG and the Auxiliary-space Maxwell Solver (AMS) in the hypre library for the 3D Laplacian operator and the electromagnetic diffusion, respectively. In time to solution for a full solve an MPI-OmpSs hybrid improves over an all-MPI approach in strong scaling at full core count (32 threads per single Haswell node of the Cray XC40) and maintains this per node advantage as both weak scale to thousands of cores, with MPI between nodes.

  8. Development of Modeling and Simulation for Magnetic Particle Inspection Using Finite Elements

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun-Youl [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    Magnetic particle inspection (MPI) is a widely used nondestructive inspection method for aerospace applications essentially limited to experiment-based approaches. The analysis of MPI characteristics that affect sensitivity and reliability contributes not only reductions in inspection design cost and time but also improvement of analysis of experimental data. Magnetic particles are easily attracted toward a high magnetic field gradient. Selection of a magnetic field source, which produces a magnetic field gradient large enough to detect a defect in a test sample or component, is an important factor in magnetic particle inspection. In this work a finite element method (FEM) has been employed for numerical calculation of the MPI simulation technique. The FEM method is known to be suitable for complicated geometries such as defects in samples. This thesis describes the research that is aimed at providing a quantitative scientific basis for magnetic particle inspection. A new FEM solver for MPI simulation has been developed in this research for not only nonlinear reversible permeability materials but also irreversible hysteresis materials that are described by the Jiles-Atherton model. The material is assumed to have isotropic ferromagnetic properties in this research (i.e., the magnetic properties of the material are identical in all directions in a single crystal). In the research, with a direct current field mode, an MPI situation has been simulated to measure the estimated volume of magnetic particles around defect sites before and after removing any external current fields. Currently, this new MPI simulation package is limited to solving problems with the single current source from either a solenoid or an axial directional current rod.

  9. Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics.

    Directory of Open Access Journals (Sweden)

    Jan Sedlacik

    Full Text Available The purpose of this work was to demonstrate the capability of magnetic particle imaging (MPI to assess the hemodynamics in a realistic 3D aneurysm model obtained by additive manufacturing. MPI was compared with magnetic resonance imaging (MRI and dynamic digital subtraction angiography (DSA.The aneurysm model was of saccular morphology (7 mm dome height, 5 mm cross-section, 3-4 mm neck, 3.5 mm parent artery diameter and connected to a peristaltic pump delivering a physiological flow (250 mL/min and pulsation rate (70/min. High-resolution (4 h long 4D phase contrast flow quantification (4D pc-fq MRI was used to directly assess the hemodynamics of the model. Dynamic MPI, MRI, and DSA were performed with contrast agent injections (3 mL volume in 3 s through a proximally placed catheter.4D pc-fq measurements showed distinct pulsatile flow velocities (20-80 cm/s as well as lower flow velocities and a vortex inside the aneurysm. All three dynamic methods (MPI, MRI, and DSA also showed a clear pulsation pattern as well as delayed contrast agent dynamics within the aneurysm, which is most likely caused by the vortex within the aneurysm. Due to the high temporal resolution of MPI and DSA, it was possible to track the contrast agent bolus through the model and to estimate the average flow velocity (about 60 cm/s, which is in accordance with the 4D pc-fq measurements.The ionizing radiation free, 4D high resolution MPI method is a very promising tool for imaging and characterization of hemodynamics in human. It carries the possibility of overcoming certain disadvantages of other modalities like considerably lower temporal resolution of dynamic MRI and limited 2D characteristics of DSA. Furthermore, additive manufacturing is the key for translating powerful pre-clinical techniques into the clinic.

  10. Usefulness of myocardial parametric imaging to evaluate myocardial viability in experimental and in clinical studies.

    Science.gov (United States)

    Korosoglou, G; Hansen, A; Bekeredjian, R; Filusch, A; Hardt, S; Wolf, D; Schellberg, D; Katus, H A; Kuecherer, H

    2006-03-01

    To evaluate whether myocardial parametric imaging (MPI) is superior to visual assessment for the evaluation of myocardial viability. Myocardial contrast echocardiography (MCE) was assessed in 11 pigs before, during, and after left anterior descending coronary artery occlusion and in 32 patients with ischaemic heart disease by using intravenous SonoVue administration. In experimental studies perfusion defect area assessment by MPI was compared with visually guided perfusion defect planimetry. Histological assessment of necrotic tissue was the standard reference. In clinical studies viability was assessed on a segmental level by (1) visual analysis of myocardial opacification; (2) quantitative estimation of myocardial blood flow in regions of interest; and (3) MPI. Functional recovery between three and six months after revascularisation was the standard reference. In experimental studies, compared with visually guided perfusion defect planimetry, planimetric assessment of infarct size by MPI correlated more significantly with histology (r2 = 0.92 versus r2 = 0.56) and had a lower intraobserver variability (4% v 15%, p < 0.05). In clinical studies, MPI had higher specificity (66% v 43%, p < 0.05) than visual MCE and good accuracy (81%) for viability detection. It was less time consuming (3.4 (1.6) v 9.2 (2.4) minutes per image, p < 0.05) than quantitative blood flow estimation by regions of interest and increased the agreement between observers interpreting myocardial perfusion (kappa = 0.87 v kappa = 0.75, p < 0.05). MPI is useful for the evaluation of myocardial viability both in animals and in patients. It is less time consuming than quantification analysis by regions of interest and less observer dependent than visual analysis. Thus, strategies incorporating this technique may be valuable for the evaluation of myocardial viability in clinical routine.

  11. The effect of patient anxiety and depression on motion during myocardial perfusion SPECT imaging

    International Nuclear Information System (INIS)

    Lyra, Vassiliki; Kallergi, Maria; Rizos, Emmanouil; Lamprakopoulos, Georgios; Chatziioannou, Sofia N.

    2016-01-01

    Patient motion during myocardial perfusion SPECT imaging (MPI) may be triggered by a patient’s physical and/or psychological discomfort. The aim of this study was to investigate the impact of state anxiety (patient’s reaction to exam-related stress), trait anxiety (patient’s personality characteristic) and depression on patient motion during MPI. All patients that underwent MPI in our department in a six-month period were prospectively enrolled. One hundred eighty-three patients (45 females; 138 males) filled in the State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI), along with a short questionnaire regarding their age, height and weight, level of education in years, occupation, and marital status. Cardiovascular and other co-morbidity factors were also evaluated. Through inspection of raw data on cinematic display, the presence or absence of patient motion was registered and classified into mild, moderate and severe, for both phases involved in image acquisition. The correlation of patient motion in the stress and delay phases of MPI and each of the other variables was investigated and the corresponding Pearson’s coefficients of association were calculated. The anxiety-motion (r = 0.43, P < 0.0001) and depression-motion (r = 0.32, P < 0.0001) correlation results were moderately strong and statistically significant for the female but not the male patients. All the other variables did not demonstrate any association with motion in MPI, except a weak correlation between age and motion in females (r = 0.23, P < 0.001). The relationship between anxiety-motion and depression-motion identified in female patients represents the first supporting evidence of psychological discomfort as predisposing factor for patient motion during MPI

  12. The effect of patient anxiety and depression on motion during myocardial perfusion SPECT imaging.

    Science.gov (United States)

    Lyra, Vassiliki; Kallergi, Maria; Rizos, Emmanouil; Lamprakopoulos, Georgios; Chatziioannou, Sofia N

    2016-08-22

    Patient motion during myocardial perfusion SPECT imaging (MPI) may be triggered by a patient's physical and/or psychological discomfort. The aim of this study was to investigate the impact of state anxiety (patient's reaction to exam-related stress), trait anxiety (patient's personality characteristic) and depression on patient motion during MPI. All patients that underwent MPI in our department in a six-month period were prospectively enrolled. One hundred eighty-three patients (45 females; 138 males) filled in the State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI), along with a short questionnaire regarding their age, height and weight, level of education in years, occupation, and marital status. Cardiovascular and other co-morbidity factors were also evaluated. Through inspection of raw data on cinematic display, the presence or absence of patient motion was registered and classified into mild, moderate and severe, for both phases involved in image acquisition. The correlation of patient motion in the stress and delay phases of MPI and each of the other variables was investigated and the corresponding Pearson's coefficients of association were calculated. The anxiety-motion (r = 0.43, P depression-motion (r = 0.32, P patients. All the other variables did not demonstrate any association with motion in MPI, except a weak correlation between age and motion in females (r = 0.23, P anxiety-motion and depression-motion identified in female patients represents the first supporting evidence of psychological discomfort as predisposing factor for patient motion during MPI.

  13. Impact of age on the selection of nuclear cardiology stress protocols: The INCAPS (IAEA nuclear cardiology protocols) study.

    Science.gov (United States)

    Al-Mallah, Mouaz H; Pascual, Thomas N B; Mercuri, Mathew; Vitola, João V; Karthikeyan, Ganesan; Better, Nathan; Dondi, Maurizio; Paez, Diana; Einstein, Andrew J

    2018-05-15

    There is growing concern about radiation exposure from nuclear myocardial perfusion imaging (MPI), particularly among younger patients who are more prone to develop untoward effects of ionizing radiation, and hence US and European professional society guidelines recommend age as a consideration in weighing radiation risk from MPI. We aimed to determine how patient radiation doses from MPI vary across age groups in a large contemporary international cohort. Data were collected as part of a global cross-sectional study of centers performing MPI coordinated by the International Atomic Energy Agency (IAEA). Sites provided information on each MPI study completed during a single week in March-April 2013. We compared across age groups laboratory adherence to pre-specified radiation-related best practices, radiation effective dose (ED; a whole-body measure reflecting the amount of radiation to each organ and its relative sensitivity to radiation's deleterious effects), and the proportion of patients with ED ≤ 9 mSv, a target level specified in guidelines. Among 7911 patients undergoing MPI in 308 laboratories in 65 countries, mean ED was 10.0 ± 4.5 mSv with slightly higher exposure among younger age groups (trend p value < 0.001). There was no difference in the proportion of patients with ED ≤ 9 mSv across age groups, or in adherence to best practices based on the median age of patients in a laboratory. In contemporary nuclear cardiology practice, the age of the patient appears not to impact protocol selection and radiation dose, contrary to professional society guidelines. Copyright © 2018. Published by Elsevier B.V.

  14. The clinical value of 99Tcm-N-NOET exercise and delayed myocardial perfusion imaging in patients with hypertension

    International Nuclear Information System (INIS)

    Wei Hua; Li Sijin; Liu Jianzhong; Wu Zhifang; Liu Haiyan; Hu Guang; Wang Jin; Li Qing

    2010-01-01

    Objective: To investigate clinical significance of the 99 Tc m -bis (N-ethoxy-N-ethyl-dithiocar-bamato) nitridotechnetium ( 99 Tc m -N-NOET) exercise and delayed myocardial perfusion imaging (MPI) in hypertensive patients. Methods: Sixty patients with hypertension and 19 normal subjects were carried out 99 Tc m -N-NOET exercise and delayed MPI, and analyzed the results of MPI, exercise electrocardiography (ECG), cardiac function parameters end-diastolic volume (EDV), end-systolic volume (ESV), left ventricular ejection fraction (LVEF), triangle open LVEF (LVEF exercis-LVEF delay) and coronary angiography (CAG). Results: 1) Sixty patients with hypertension, 22 cases (36.7%) of exercise ECG were abnormal, 16 cases (26.7%) were the chest tightness in exercise, 13 cases (21.7%) were blood pressure excessive reaction in exercise; control group, 2 cases (10.5%) of exercise ECG were abnormal, 1 case (5.3%, 1/19) was chest tightness in exercise, no person was blood pressure response in excessive. 2) The positive rate of myocardial perfusion in hypertensive group was significantly higher than the control group (31.75%vs. 5.30%, P 0.05), triangle open LVEF 2 =4.501, P 2 =0.25, P>0.05). The sensitivity, specificity and accuracy of 99 Tc m -N-NOET MPI were 72.7%, 87.5% and 78.9%. Conclusions: 1) 99 Tc m -N-NOET exercise and delayde MPI can diagnose whether hypertension patients with myocardial ischemia or not. 2) triangle open LVEF of hypertensive patients reduced, triangle open LVEF is lower in hypertensive patients of MPI-positive. (authors)

  15. Chest Pain with Normal Thallium-201 Myocardial Perfusion Image – Is It Really Normal?

    Science.gov (United States)

    Liu, Pang-Yen; Lin, Wen-Yu; Lin, Li-Fan; Lin, Chin-Sheng; Lin, Wei-Shiang; Cheng, Shu-Meng; Yang, Shih-Ping; Liou, Jun-Ting

    2016-01-01

    Background Thallium-201 myocardial perfusion image (MPI) is commonly used to detect coronary artery disease in patients with chest pain. Although a normal thallium-201 MPI result is generally considered to be a good prognosis and further coronary angiogram is not recommended, there are still a few patients who suffer from unexpected acute coronary events. The aim of this study was to investigate the clinical prognosis in patients with normal thallium-201 MPI. Methods From January 2006 to August 2012, a total 22,003 patients undergoing thallium-201 MPI in one tertiary center were screened. Of these, 8092 patients had normal results and were investigated retrospectively. During follow-up, 54 patients underwent coronary angiogram because of refractory typical angina pectoris or unexpected acute coronary events. These 54 patients were divided into 2 groups: group I consisted of 26 (48.1%) patients with angiography-proven significant coronary artery stenosis, and group II consisted of 28 (51.9%) patients without significant stenosis. Results Patients in group I had a higher prevalence of prior coronary stenting and electrocardiographic features of ST depression compared with patients in group II. The multivariate analysis demonstrated that both prior coronary stenting and ST depression were risk predictors of unexpected acute coronary events in the patients with normal thallium-201 MPI [odds ratio (OR), 5.93; 95% confidence interval (CI): 1.03-34.06, p = 0.05 and OR, 7.10; 95% CI: 1.28-39.51, p = 0.03,respectively]. Conclusions Although there is a low incidence of unexpected acute coronary events in patients with chest pain and normal thallium-201 MPI, physicians should be aware of the potentials risk in certain patients in this specific population. PMID:27274174

  16. Improving results of surgery for fecal peritonitis due to perforated colorectal disease: A single center experience.

    Science.gov (United States)

    Mineccia, Michela; Zimmitti, Giuseppe; Ribero, Dario; Giraldi, Francesco; Bertolino, Franco; Brambilla, Romeo; Ferrero, Alessandro

    2016-01-01

    fecal peritonitis due to colorectal perforation is a dramatic event characterized by high mortality. Our study aims at determining how results of sigmoid resection (eventually extended to upper rectum) for colorectal perforation with fecal peritonitis changed in recent years and which factors affected eventual changes. Seventy-four patients were operated on at our institution (2005-2014) for colorectal perforation with fecal peritonitis and were divided into two numerically equal groups (operated on before (ERA1-group) and after (ERA2-group) May 2010). Mannheim Peritonitis Index (MPI) was calculated for each patient. Characteristics of two groups were compared. Predictors of postoperative outcomes were identified. Postoperative overall complications, major complications, and mortality occurred in 59%, 28%, and 18% of cases, respectively, and were less frequent in ERA2-group (51%, 16%, and 8%, respectively), compared to ERA1-group (68%, 41%, and 27%, respectively; p = .155, .02, and .032, respectively). Such results paralleled lower MPI values in ERA2-group, compared to ERA1-group (23(16-39) vs. 28(21-43), p = .006). Using receiver operating characteristic analysis, the best cut-off value for MPI for predicting postoperative complications and mortality was 28.5. MPI>28 was the only independent predictor of postoperative overall (p = .009, OR = 4.491) and major complications (p peritonitis longer than 24 h (p = .045, OR = 17.099). results of surgery for colorectal perforation with fecal peritonitis have improved over time, matching a concurrent decrease of MPI values and a better preoperative patient management. MPI value may help in selecting patients benefitting from surgical treatment. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

  17. Stress-induced ST-segment deviation in relation to the presence and severity of coronary artery disease in patients with normal myocardial perfusion imaging.

    Science.gov (United States)

    Weinsaft, Jonathan W; Manoushagian, Shant J; Patel, Taral; Shakoor, Aqsa; Kim, Robert J; Mirchandani, Sunil; Lin, Fay; Wong, Franklin J; Szulc, Massimiliano; Okin, Peter M; Kligfield, Paul D; Min, James K

    2009-01-01

    To assess the utility of stress electrocardiography (ECG) for identifying the presence and severity of obstructive coronary artery disease (CAD) defined by coronary computed tomographic angiography (CCTA) among patients with normal nuclear myocardial perfusion imaging (MPI). The study population comprised 119 consecutive patients with normal MPI who also underwent CCTA (interval 3.5+/-3.8 months). Stress ECG was performed at the time of MPI. CCTA and MPI were interpreted using established scoring systems, and CCTA was used to define the presence and extent of CAD, which was quantified by a coronary artery jeopardy score. Within this population, 28 patients (24%) had obstructive CAD identified by CCTA. The most common CAD pattern was single-vessel CAD (61%), although proximal vessel involvement was present in 46% of patients. Patients with CAD were nearly three times more likely to have positive standard test responses (1 mm ST-segment deviation) than patients with patent coronary arteries (36 vs. 13%, P=0.007). In multivariate analysis, a positive ST-segment test response was an independent marker for CAD (odds ratio: 2.02, confidence interval: 1.09-3.78, P=0.03) even after adjustment for a composite of clinical cardiac risk factors (odds ratio: 1.85, confidence interval: 1.05-3.23, P=0.03). Despite uniformly normal MPI, mean coronary jeopardy score was three-fold higher among patients with positive compared to those with negative ST-segment response to exercise or dobutamine stress (1.9+/-2.7 vs. 0.5+/-1.4, P=0.03). Stress-induced ST-segment deviation is an independent marker for obstructive CAD among patients with normal MPI. A positive stress ECG identifies patients with a greater anatomic extent of CAD as quantified by coronary jeopardy score.

  18. Tei index in neonatal respiratory distress and perinatal asphyxia

    Directory of Open Access Journals (Sweden)

    Ahmed Anwer Attia Khattab

    2015-09-01

    Full Text Available Cardiovascular compromise is a common complication of neonatal respiratory distress and perinatal asphyxia. Tei index is a Doppler-derived index for the assessment of overall left ventricular function that combines systolic and diastolic time intervals. Aim: Assess the role of MPI versus cardiac troponin I as early indicator of hypoxic cardiac damage in neonates with respiratory distress or perinatal asphyxia. The present work was conducted on forty neonates, 15 with neonatal respiratory distress (group I, 15 with perinatal asphyxia (group II, and 10 apparently healthy neonates as a control (group III. All have: Detailed history-thorough clinical examination-Plain X-ray-ECG-Two dimensional, M-mode and Doppler echocardiographic examination with the measurement of both myocardial performance index (MPI of the right and left ventricle-Serum cardiac troponin I. Results: There was statistically significant increase in serum cardiac troponin I in groups I and II than group III. Left and right ventricular myocardial performance index (MPI were increased in group I and II than the control group. No correlation between Tei index and each of postnatal age, apgar score at 5-min, heart rate, serum cardiac troponin I, ejection fraction and fractional shortening, but there was direct relationship between MPI and LVEDD and inverse relationship between MPI and each of EF% and FS%. But there was significant correlation between L.V. MPI and gestational age. Conclusion: Tei index was higher in neonates with respiratory distress and neonates with perinatal asphyxia than in normal neonates despite normal or even increased ejection fraction which indicates that these patients may have subclinical ventricular dysfunction which should be followed up carefully.

  19. Magnetic particle imaging for in vivo blood flow velocity measurements in mice

    Science.gov (United States)

    Kaul, Michael G.; Salamon, Johannes; Knopp, Tobias; Ittrich, Harald; Adam, Gerhard; Weller, Horst; Jung, Caroline

    2018-03-01

    Magnetic particle imaging (MPI) is a new imaging technology. It is a potential candidate to be used for angiographic purposes, to study perfusion and cell migration. The aim of this work was to measure velocities of the flowing blood in the inferior vena cava of mice, using MPI, and to evaluate it in comparison with magnetic resonance imaging (MRI). A phantom mimicking the flow within the inferior vena cava with velocities of up to 21 cm s‑1 was used for the evaluation of the applied analysis techniques. Time–density and distance–density analyses for bolus tracking were performed to calculate flow velocities. These findings were compared with the calibrated velocities set by a flow pump, and it can be concluded that velocities of up to 21 cm s‑1 can be measured by MPI. A time–density analysis using an arrival time estimation algorithm showed the best agreement with the preset velocities. In vivo measurements were performed in healthy FVB mice (n  =  10). MRI experiments were performed using phase contrast (PC) for velocity mapping. For MPI measurements, a standardized injection of a superparamagnetic iron oxide tracer was applied. In vivo MPI data were evaluated by a time–density analysis and compared to PC MRI. A Bland–Altman analysis revealed good agreement between the in vivo velocities acquired by MRI of 4.0  ±  1.5 cm s‑1 and those measured by MPI of 4.8  ±  1.1 cm s‑1. Magnetic particle imaging is a new tool with which to measure and quantify flow velocities. It is fast, radiation-free, and produces 3D images. It therefore offers the potential for vascular imaging.

  20. Cardiovascular outcomes after pharmacologic stress myocardial perfusion imaging.

    Science.gov (United States)

    Lee, Douglas S; Husain, Mansoor; Wang, Xuesong; Austin, Peter C; Iwanochko, Robert M

    2016-04-01

    While pharmacologic stress single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is used for noninvasive evaluation of patients who are unable to perform treadmill exercise, its impact on net reclassification improvement (NRI) of prognosis is unknown. We evaluated the prognostic value of pharmacologic stress MPI for prediction of cardiovascular death or non-fatal myocardial infarction (MI) within 1 year at a single-center, university-based laboratory. We examined continuous and categorical NRI of pharmacologic SPECT-MPI for prediction of outcomes beyond clinical factors alone. Six thousand two hundred forty patients (median age 66 years [IQR 56-74], 3466 men) were studied and followed for 5963 person-years. SPECT-MPI variables associated with increased risk of cardiovascular death or non-fatal MI included summed stress score, stress ST-shift, and post-stress resting left ventricular ejection fraction ≤50%. Compared to a clinical model which included age, sex, cardiovascular disease, risk factors, and medications, model χ(2) (210.5 vs. 281.9, P statistic (0.74 vs. 0.78, P stress score, stress ST-shift and stress resting left ventricular ejection fraction). SPECT-MPI predictors increased continuous NRI by 49.4% (P 3% annualized risk of cardiovascular death or non-fatal MI, yielded a 15.0% improvement in NRI (95% CI 7.6%-27.6%, P stress MPI substantially improved net reclassification of cardiovascular death or MI risk beyond that afforded by clinical factors. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Using OFI libfabric on Cori/Edison

    Energy Technology Data Exchange (ETDEWEB)

    Pritchard, Howard Porter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Choi, Sung-Eun [Cray, Inc., Seattle, WA (United States)

    2016-08-22

    These are slides from a presentation during an NERSC site visit to Los Alamos National Laboratory. The following topics are covered: building/installing libfabric, OpenMPI using libfabric, MPICH using libfabric, Open SHMEM (Sandia), other applications, and what is next. The next steps are: get a libfabric 1.4 out, it would be nice to have libfabric 1.4 installed in system space on Cori, add libfabric modules on Cori, might be a good idea to have a SLURM PMI module to simplify its use when building/using Open MPI and MPICH built to use libfabric, and upgrade Edison to CLE 5.2 UP04 or newer.

  2. Parallelization characteristics of the DeCART code

    International Nuclear Information System (INIS)

    Cho, J. Y.; Joo, H. G.; Kim, H. Y.; Lee, C. C.; Chang, M. H.; Zee, S. Q.

    2003-12-01

    This report is to describe the parallelization characteristics of the DeCART code and also examine its parallel performance. Parallel computing algorithms are implemented to DeCART to reduce the tremendous computational burden and memory requirement involved in the three-dimensional whole core transport calculation. In the parallelization of the DeCART code, the axial domain decomposition is first realized by using MPI (Message Passing Interface), and then the azimuthal angle domain decomposition by using either MPI or OpenMP. When using the MPI for both the axial and the angle domain decomposition, the concept of MPI grouping is employed for convenient communication in each communication world. For the parallel computation, most of all the computing modules except for the thermal hydraulic module are parallelized. These parallelized computing modules include the MOC ray tracing, CMFD, NEM, region-wise cross section preparation and cell homogenization modules. For the distributed allocation, most of all the MOC and CMFD/NEM variables are allocated only for the assigned planes, which reduces the required memory by a ratio of the number of the assigned planes to the number of all planes. The parallel performance of the DeCART code is evaluated by solving two problems, a rodded variation of the C5G7 MOX three-dimensional benchmark problem and a simplified three-dimensional SMART PWR core problem. In the aspect of parallel performance, the DeCART code shows a good speedup of about 40.1 and 22.4 in the ray tracing module and about 37.3 and 20.2 in the total computing time when using 48 CPUs on the IBM Regatta and 24 CPUs on the LINUX cluster, respectively. In the comparison between the MPI and OpenMP, OpenMP shows a somewhat better performance than MPI. Therefore, it is concluded that the first priority in the parallel computation of the DeCART code is in the axial domain decomposition by using MPI, and then in the angular domain using OpenMP, and finally the angular

  3. The Research of the Parallel Computing Development from the Angle of Cloud Computing

    Science.gov (United States)

    Peng, Zhensheng; Gong, Qingge; Duan, Yanyu; Wang, Yun

    2017-10-01

    Cloud computing is the development of parallel computing, distributed computing and grid computing. The development of cloud computing makes parallel computing come into people’s lives. Firstly, this paper expounds the concept of cloud computing and introduces two several traditional parallel programming model. Secondly, it analyzes and studies the principles, advantages and disadvantages of OpenMP, MPI and Map Reduce respectively. Finally, it takes MPI, OpenMP models compared to Map Reduce from the angle of cloud computing. The results of this paper are intended to provide a reference for the development of parallel computing.

  4. Rest/stress myocardial perfusion imaging: A means to prevent missed acute ischemic coronary syndrome diagnoses

    International Nuclear Information System (INIS)

    Fink-Bennett, D.; Pattekar, A.M.

    2002-01-01

    Aim: The sensitivity and specificity of rest/stress (R/S) myocardial perfusion imaging (MPI) in detecting an acute ischemic coronary syndrome (AICS) was determined in 100 consecutive patients (pts) admitted to the Chest Pain Clinic-Observation Unit (CPC-OU) with chest pain (CP) of suspected cardiac etiology and a negative (neg) or non diagnostic (dx) EKG. There were 57 females and 43 males, 30-83 years of age. 50 studies were performed from 1/15/98 to 4/2/98; 50 from 11/19/99 to 1/10/00. Material and Methods: An AICS was deemed present if a reversible perfusion defect was demonstrated scintigraphically; a ?50% luminal narrow angiographically. No AICS if the pt had a normal R/S MPI, a fixed defect with normal wall motion and thickening, a neg cardiac catheterization, or was free of cardiac symptoms and had no history of a vascular event for 2-3 years post CPC-OU admission. 13 pts with a positive MPI had a cardiac catheterization, none with a neg MPI. SPECT rest MPI's were performed 30-90 minutes (mins) post 10.0 mCi of technetium 99m Sestamibi. SPECT stress MPI's were performed following a 6-8 hour acute myocardial infarction enzyme (CP-MB/Troponin 1) rule out and 30-90 mins post 30.0 mCi of technetium 99m Sestamibi. Results: 29 pts were lost to follow-up. There were 12 true positive, 5 false positive, 54 true negative and 0 false negative studies. The sensitivity, specificity, positive and negative predictive value of a R/S MPI in detecting an AICS is 100%, 91%, 70% and 100%, respectively. An AICS was detected in 12% of pts admitted to the CPC-OU; a finding that correlates with its reported incidence of 2-12%. 6 were managed medically, 3 required emergent bypass surgery, 3 were stented. Conclusion: R/S MPI should be included in the CPC-OU dx work-up of pts with CP of suspected cardiac etiology to prevent missed AICS diagnoses. Patient care will be optimized and health care and medical malpractice awards for failure to diagnosis an acute myocardial infarction

  5. Diseño e instalación de una red industrial para el control de 2 líneas de transportadores de periódicos y control de consumo de tinta negra en planta sur de diario El Universo

    OpenAIRE

    Zhagui Quirola, Andrés Gabriel

    2009-01-01

    La red MPI instalada en el diario El Universo, mejora los procesos necesarios para la impresión del diario; elimina las islas que antes funcionaban. Los anteriores procesos utilizaban controladores lógicos de diferentes marcas, dificultando su comunicación. La implementación exigió modernizar ciertos procesos que intervienen en la producción e integrarlos dentro de la red MPI; logrando: facilitar su operación a los prensistas, disminuir el tiempo de paro e identificar fallas. Para realizar la...

  6. Accelerated Prediction of the Polar Ice and Global Ocean (APPIGO)

    Science.gov (United States)

    2015-09-30

    Dolven (Cray) and Carl Ponder ( NVIDIA ). Eric and Carl and Louis worked on OpenACC in HYCOM before the hackathon, and we had 4.5 days to get HYCOM...that runs with 60 MPI ranks, we have been using the Nvidia profiling tools to analyze performance. Initial code structures in CICE look similar to...above, we have been receiving assistance from Nvidia engineers to improve sharing of GPU devices by more than one MPI rank on a node, as will be the

  7. Spectral-element simulation of two-dimensional elastic wave propagation in fully heterogeneous media on a GPU cluster

    Science.gov (United States)

    Rudianto, Indra; Sudarmaji

    2018-04-01

    We present an implementation of the spectral-element method for simulation of two-dimensional elastic wave propagation in fully heterogeneous media. We have incorporated most of realistic geological features in the model, including surface topography, curved layer interfaces, and 2-D wave-speed heterogeneity. To accommodate such complexity, we use an unstructured quadrilateral meshing technique. Simulation was performed on a GPU cluster, which consists of 24 core processors Intel Xeon CPU and 4 NVIDIA Quadro graphics cards using CUDA and MPI implementation. We speed up the computation by a factor of about 5 compared to MPI only, and by a factor of about 40 compared to Serial implementation.

  8. A PARALLEL EXTENSION OF THE UAL ENVIRONMENT

    International Nuclear Information System (INIS)

    MALITSKY, N.; SHISHLO, A.

    2001-01-01

    The deployment of the Unified Accelerator Library (UAL) environment on the parallel cluster is presented. The approach is based on the Message-Passing Interface (MPI) library and the Perl adapter that allows one to control and mix together the existing conventional UAL components with the new MPI-based parallel extensions. In the paper, we provide timing results and describe the application of the new environment to the SNS Ring complex beam dynamics studies, particularly, simulations of several physical effects, such as space charge, field errors, fringe fields, and others

  9. DEPFET-detectors: New developments

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, G. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany)]. E-mail: gerhard.lutz@cern.ch; Andricek, L. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Eckardt, R. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Haelker, O. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Hermann, S. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Lechner, P. [MPI Semiconductor Laboratory, PNSensor GmbH, Otto Hahn Ring 6, D 81739 Munich (Germany); Richter, R. [MPI Semiconductor Laboratory, Max Planck Institut fuer Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Schaller, G. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Schopper, F. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Soltau, H. [MPI Semiconductor Laboratory, PNSensor GmbH, Otto Hahn Ring 6, D 81739 Munich (Germany); Strueder, L. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Treis, J. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Woelfl, S. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany); Zhang, C. [MPI Semiconductor Laboratory, Max Planck Institut fuer extraterrestrische Physik, Otto Hahn Ring 6, D 81739 Munich (Germany)

    2007-03-01

    The Depleted Field Effect Transistor (DEPFET) detector-amplifier structure forms the basis of a variety of detectors being developed at the MPI semiconductor laboratory. These detectors are foreseen to be used in astronomy and particle physics as well as other fields of science. The detector developments are described together with some intended applications. They comprise the X-ray astronomy missions XEUS and SIMBOL-X as well as the vertex detector of the planned International Linear Collider (ILC). All detectors are produced in the MPI semiconductor laboratory that has a complete silicon technology available.

  10. DEPFET-detectors: New developments

    International Nuclear Information System (INIS)

    Lutz, G.; Andricek, L.; Eckardt, R.; Haelker, O.; Hermann, S.; Lechner, P.; Richter, R.; Schaller, G.; Schopper, F.; Soltau, H.; Strueder, L.; Treis, J.; Woelfl, S.; Zhang, C.

    2007-01-01

    The Depleted Field Effect Transistor (DEPFET) detector-amplifier structure forms the basis of a variety of detectors being developed at the MPI semiconductor laboratory. These detectors are foreseen to be used in astronomy and particle physics as well as other fields of science. The detector developments are described together with some intended applications. They comprise the X-ray astronomy missions XEUS and SIMBOL-X as well as the vertex detector of the planned International Linear Collider (ILC). All detectors are produced in the MPI semiconductor laboratory that has a complete silicon technology available

  11. Towards Porting a Real-World Seismological Application to the Intel MIC Architecture

    OpenAIRE

    V. Weinberg

    2014-01-01

    This whitepaper aims to discuss first experiences with porting an MPI-based real-world geophysical application to the new Intel Many Integrated Core (MIC) architecture. The selected code SeisSol is an application written in Fortran that can be used to simulate earthquake rupture and radiating seismic wave propagation in complex 3-D heterogeneous materials. The PRACE prototype cluster EURORA at CINECA, Italy, was accessed to analyse the MPI-performance of SeisSol on Intel Xeon Phi on both sing...

  12. Prognostic Value of Cardiac Time Intervals by Tissue Doppler Imaging M-Mode in Patients With Acute ST-Segment-Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; Søgaard, Peter

    2013-01-01

    Background- Color tissue Doppler imaging M-mode through the mitral leaflet is an easy and precise method to estimate all cardiac time intervals from 1 cardiac cycle and thereby obtain the myocardial performance index (MPI). However, the prognostic value of the cardiac time intervals and the MPI...... assessed by color tissue Doppler imaging M-mode through the mitral leaflet in patients with ST-segment-elevation myocardial infarction (MI) is unknown. Methods and Results- In total, 391 patients were admitted with an ST-segment-elevation MI, treated with primary percutaneous coronary intervention...

  13. Multiscale phase inversion of seismic marine data

    KAUST Repository

    Fu, Lei

    2017-08-17

    We test the feasibility of applying multiscale phase inversion (MPI) to seismic marine data. To avoid cycle-skipping, the multiscale strategy temporally integrates the traces several times, i.e. high-order integration, to produce low-boost seismograms that are used as input data for the initial iterations of MPI. As the iterations proceed, higher frequencies in the data are boosted by using integrated traces of lower order as the input data. Results with synthetic data and field data from the Gulf of Mexico produce robust and accurate results if the model does not contain strong velocity contrasts such as salt-sediment interfaces.

  14. Comparison of Hemodynamic Effects and Negative Predictive Value of Normal Adenosine Gated Myocardial Perfusion Scan With or Without Caffeine Abstinence

    International Nuclear Information System (INIS)

    Zaman, Maseeh uz; Fatima, Nosheen; Zaman, Areeba; Zaman, Unaiza; Tahseen, Rabia

    2016-01-01

    For vasodilator stress, myocardial perfusion imaging (MPI) with at least 12-h caffeine abstinence is recommended, as it attenuates cardiovascular hyperemic response of adenosine and dipyridamole. However, many published conflicting results have shown no significant effect upon perfusion abnormalities in MPI performed without caffeine abstinence. The aim of this study was to compare the hemodynamic changes and negative predictive value (NPV) of normal MPIs with adenosine stress performed with or without caffeine abstinence. This was a prospective study that accrued 50 patients from May 2013 till September 2013 and followed till November 2014. These patients had a normal adenosine-gated MPI (GMPI) with technetium-99m methoxy isobutyl isonitrile ( 99m Tc-MIBI) after 12-h caffeine abstinence (no-caffeine). Next day, all patients had a repeat adenosine stress within 60 min after ingestion of a cup of coffee (about 80 mg of caffeine) followed by no MPI in 30 patients due to concern about radiation dose (prior-caffeine adenosine—no MPI; group A). Twenty patients opted for a repeat MPI (prior-caffeine adenosine—MPI; group B). Adenosine-induced hemodynamic response and NPV of the normal MPI with no-caffeine and prior-caffeine protocols were compared. The mean age of the study cohort was 57 ± 9 years with a male-to-female ratio of 76:24% and mean body mass index (BMI) of 26.915 ± 4.121 kg/m 2 . Prevalence of hypertension, diabetes, dyslipidemia, and positive family history were 76%, 20%, 22%, and 17%, respectively. Comparison of group A with group B revealed no significant difference in demographic parameters, hemodynamic or electrocardiography (ECG) parameters, or left ventricular (LV) function parameters during adenosine intervention with prior-caffeine and no-caffeine protocols. During the follow-up, no fatal myocardial infarction (MI) was reported but 6 nonfatal MIs were reported based upon the history of short hospitalization for chest pain but without biochemical

  15. Clinical application of 99Tcm-tetrofosmin in diagnosis patients with coronary heart disease

    International Nuclear Information System (INIS)

    Li Na; Chen Song; Wang Xiaobei; Wang Ying; Yin Yafu; Li Xuena; Li Yaming; Wang Lijuan; He Zuoxiang

    2012-01-01

    Objective: To evaluate the diagnostic value of 99 Tc m -tetrofosmin(TF) stress-rest MPI in detecting CHD. Methods: Eighty patients with suspected CHD who had stress-rest MPI from October 2009 to April 2011 were retrospectively analyzed.Forty underwent 99 Tc m -TF (group A) and 40 received 99 Tc m -MIBI (group B) stress-rest MPI. Heart/lung (H/L) ratios of these two groups were compared.CAG was performed on group A patients 3 months before and after MPI. Stenosis of more than 50% in CAG was used as a standard to evaluate the diagnostic efficiency of 99 Tc m -TF MPI. Paired t test and χ 2 test were used to compare the data. Results: H/L ratios of rest and stress from 99 Tc m -TF images were 6.73 ± 1.21 and 6.94 ± 1.69, while those from 99 Tc m -MIBI images were 6.58 ± 1.94 and 6.64 ± 1.81, respectively. There was no difference between 99 Tc m -TF and 99 Tc m -MIBI imaging in both rest and stress (t=0.41, 0.78, both P>0.05). There was no difference between H/L ratios from stress and rest 99 Tc m -TF imaging (t=0.69, P >0.05). Twenty-four patients who underwent 99 Tc m -TF imaging had abnormal perfusion (60.0%, 24/40), including 20 LAD, 11 LCX and 14 RCA. Twenty-three among these 40 patients had abnormal CAG results (57.5%, 23/40), including 19 LAD, 12 LCX, and 11 RCA. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 99 Tc m -TF stress-rest MPI were 87.0% (20/23), 76.5% (13/17), 82.5% (33/40), 83.3% (20/24) and 81.2% (13/16), respectively. The sensitivities of 99 Tc m -TF stress-rest MPI for detection of LAD, LCX and RCA were 89.5% (17/19), 83.3% (10/12) and 90.9% (10/11), respectively,and positive predictive values were 85.0% (17/20), 90.9% (10/11) and 71.4% (10/14), respectively. There was no significant difference for sensitivity and positive predictive value of 99 Tc m -TF MPI among different vessels (χ 2 =0.377 and 1.789, both P>0.05). Conclusions: 99 Tc m -TF MPI has comparative imaging quality to 99 Tc m

  16. Scalability of Semi-Implicit Time Integrators for Nonhydrostatic Galerkin-based Atmospheric Models on Large Scale Cluster

    Science.gov (United States)

    2011-01-01

    present performance statistics to explain the scalability behavior. Keywords-atmospheric models, time intergrators , MPI, scal- ability, performance; I...across inter-element bound- aries. Basis functions are constructed as tensor products of Lagrange polynomials ψi (x) = hα(ξ) ⊗ hβ(η) ⊗ hγ(ζ)., where hα

  17. 32 CFR 637.7 - Drug enforcement activities.

    Science.gov (United States)

    2010-07-01

    .... Provost marshals and U.S. Army law enforcement supervisors at all levels will ensure that active drug... National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND... important nature of the drug enforcement effort. (a) MPI and DAC detectives/investigators will conduct...

  18. Myocardial perfusion imaging for predicting cardiac events in Japanese patients with advanced chronic kidney disease: 1-year interim report of the J-ACCESS 3 investigation

    International Nuclear Information System (INIS)

    Joki, Nobuhiko; Hase, Hiroki; Kawano, Yuhei; Nakamura, Satoko; Nakajima, Kenichi; Hatta, Tsuguru; Nishimura, Shigeyuki; Moroi, Masao; Nakagawa, Susumu; Kasai, Tokuo; Kusuoka, Hideo; Takeishi, Yasuchika; Momose, Mitsuru; Takehana, Kazuya; Nanasato, Mamoru; Yoda, Shunichi; Nishina, Hidetaka; Matsumoto, Naoya; Nishimura, Tsunehiko

    2014-01-01

    Whether myocardial perfusion imaging (MPI) can predict cardiac events in patients with advanced conservative chronic kidney disease (CKD) remains unclear. The present multicenter prospective cohort study aimed to clarify the ability of MPI to predict cardiac events in 529 patients with CKD and estimated glomerular filtration rates (eGFR) 2 without a definitive diagnosis of coronary artery disease. All patients were assessed by stress-rest MPI with 99m Tc-tetrofosmin and analyzed using summed defect scores and QGS software. Cardiac events were analyzed 1 year after registration. Myocardial perfusion abnormalities defined as summed stress score (SSS) ≥4 and ≥8 were identified in 19 and 7 % of patients, respectively. At the end of the 1-year follow-up, 33 (6.2 %) cardiac events had occurred that included cardiac death, sudden death, nonfatal myocardial infarction, and hospitalization due to heart failure. The event-free rates at that time were 0.95, 0.90, and 0.81 for groups with SSS 0-3, 4-7, and ≥8, respectively (p = 0.0009). Thus, patients with abnormal SSS had a higher incidence of cardiac events. Multivariate Cox regression analysis showed that SSS significantly impacts the prediction of cardiac events independently of eGFR and left ventricular ejection fraction. MPI would be useful to stratify patients with advanced conservative CKD who are at high risk of cardiac events without adversely affecting damaged kidneys. (orig.)

  19. Protocol-Based Verification of Message-Passing Parallel Programs

    DEFF Research Database (Denmark)

    López-Acosta, Hugo-Andrés; Eduardo R. B. Marques, Eduardo R. B.; Martins, Francisco

    2015-01-01

    We present ParTypes, a type-based methodology for the verification of Message Passing Interface (MPI) programs written in the C programming language. The aim is to statically verify programs against protocol specifications, enforcing properties such as fidelity and absence of deadlocks. We develo...

  20. Introduction

    International Nuclear Information System (INIS)

    Raeder, J.

    1975-01-01

    The introduction to this monography gives a brief survey of the history of the MHD generator, outlines the fundamental questioning of the research concerned and then deals with the combustion gas MHD generator research programme of the working society MPI for plasma physics (IPP)/Maschinenfabrik Augsburg-Nuernberg AG (M.A.N.). (GG/LH) [de

  1. Parallel sparse direct solvers for Poisson's equation in streamer discharges

    NARCIS (Netherlands)

    M. Nool (Margreet); M. Genseberger (Menno); U. M. Ebert (Ute)

    2017-01-01

    textabstractThe aim of this paper is to examine whether a hybrid approach of parallel computing, a combination of the message passing model (MPI) with the threads model (OpenMP) can deliver good performance in streamer discharge simulations. Since one of the bottlenecks of almost all streamer

  2. Nanoparticle encapsulation in red blood cells enables blood-pool magnetic particle imaging hours after injection

    International Nuclear Information System (INIS)

    Rahmer, J; Gleich, B; Borgert, J; Antonelli, A; Sfara, C; Magnani, M; Tiemann, B; Weizenecker, J

    2013-01-01

    Magnetic particle imaging (MPI) is a new medical imaging approach that is based on the nonlinear magnetization response of super-paramagnetic iron oxide nanoparticles (SPIOs) injected into the blood stream. To date, real-time MPI of the bolus passage of an approved MRI SPIO contrast agent injected into the tail vein of living mice has been demonstrated. However, nanoparticles are rapidly removed from the blood stream by the mononuclear phagocyte system. Therefore, imaging applications for long-term monitoring require the repeated administration of bolus injections, which complicates quantitative comparisons due to the temporal variations in concentration. Encapsulation of SPIOs into red blood cells (RBCs) has been suggested to increase the blood circulation time of nanoparticles. This work presents first evidence that SPIO-loaded RBCs can be imaged in the blood pool of mice several hours after injection using MPI. This finding is supported by magnetic particle spectroscopy performed to quantify the iron concentration in blood samples extracted from the mice 3 and 24 h after injection of SPIO-loaded RBCs. Based on these results, new MPI applications can be envisioned, such as permanent 3D real-time visualization of the vessel tree during interventional procedures, bleeding monitoring after stroke, or long-term monitoring and treatment control of cardiovascular diseases. (paper)

  3. Soy compared with milk protein in a Western diet changes fecal microbiota and decreases hepatic steatosis in obese OLETF rats.

    Science.gov (United States)

    Panasevich, Matthew R; Schuster, Colin M; Phillips, Kathryn E; Meers, Grace M; Chintapalli, Sree V; Wankhade, Umesh D; Shankar, Kartik; Butteiger, Dustie N; Krul, Elaine S; Thyfault, John P; Rector, R Scott

    2017-08-01

    Soy protein is effective at preventing hepatic steatosis; however, the mechanisms are poorly understood. We tested the hypothesis that soy vs. dairy protein-based diet would alter microbiota and attenuate hepatic steatosis in hyperphagic Otsuka Long-Evans Tokushima fatty (OLETF) rats. Male OLETF rats were randomized to "Western" diets containing milk protein isolate (MPI), soy protein isolate (SPI) or 50:50 MPI/SPI (MS) (n=9-10/group; 21% kcal protein) for 16 weeks. SPI attenuated (Pcontent, and hepatic 16:1 n-7 and 18:1 n-7 PUFA concentrations) (Pbacterial 16S rRNA analysis revealed SPI-intake elicited increases (P<.05) in Lactobacillus and decreases (P<.05) in Blautia and Lachnospiraceae suggesting decreases in fecal secondary bile acids in SPI rats. SPI and MS exhibited greater (P<.05) hepatic Fxr, Fgfr4, Hnf4a, HmgCoA reductase and synthase mRNA expression compared with MPI. Overall, dietary SPI compared with MPI decreased hepatic steatosis and diacylglycerols, changed microbiota populations and altered bile acid signaling and cholesterol homeostasis in a rodent model of obesity. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Radiative transfer with scattering for domain-decomposed 3D MHD simulations of cool stellar atmospheres : numerical methods and application to the quiet, non-magnetic, surface of a solar-type star

    NARCIS (Netherlands)

    Hayek, W.; Asplund, M.; Carlsson, M.; Trampedach, R.; Collet, R.; Gudiksen, B.V.; Hansteen, V.H.; Leenaarts, J.|info:eu-repo/dai/nl/304837946

    2010-01-01

    Aims. We present the implementation of a radiative transfer solver with coherent scattering in the new BIFROST code for radiative magneto-hydrodynamical (MHD) simulations of stellar surface convection. The code is fully parallelized using MPI domain decomposition, which allows for large grid sizes

  5. Development of parallel/serial program analyzing tool

    International Nuclear Information System (INIS)

    Watanabe, Hiroshi; Nagao, Saichi; Takigawa, Yoshio; Kumakura, Toshimasa

    1999-03-01

    Japan Atomic Energy Research Institute has been developing 'KMtool', a parallel/serial program analyzing tool, in order to promote the parallelization of the science and engineering computation program. KMtool analyzes the performance of program written by FORTRAN77 and MPI, and it reduces the effort for parallelization. This paper describes development purpose, design, utilization and evaluation of KMtool. (author)

  6. Parallel algorithms for 2-D cylindrical transport equations of Eigenvalue problem

    International Nuclear Information System (INIS)

    Wei, J.; Yang, S.

    2013-01-01

    In this paper, aimed at the neutron transport equations of eigenvalue problem under 2-D cylindrical geometry on unstructured grid, the discrete scheme of Sn discrete ordinate and discontinuous finite is built, and the parallel computation for the scheme is realized on MPI systems. Numerical experiments indicate that the designed parallel algorithm can reach perfect speedup, it has good practicality and scalability. (authors)

  7. Atmospheric corrosion performance of different steels in early exposure in the coastal area region West Java, Indonesia

    Science.gov (United States)

    Nuraini, Lutviasari; Prifiharni, Siska; Priyotomo, Gadang; Sundjono, Gunawan, Hadi; Purawiardi, Ibrahim

    2018-05-01

    The performance of carbon steel, galvanized steel and aluminium after one month exposed in the atmospheric coastal area, which is in Limbangan and Karangsong Beach, West Java, Indonesia was evaluated. The corrosion rate was determined by weight loss method and the morphology of the steel after exposed was observed by Scanning Electron Microscopy(SEM)/Energy Dispersive X-Ray Analysis(EDX). The site was monitored to determine the chloride content in the marine atmosphere. Then, the corrosion products formed at carbon steel were characterized by X-Ray diffraction (XRD). The result showed the aggressively corrosion in Karangsong beach, indicated from the corrosion rate of carbon steel, galvanized steel and aluminium were 38.514 mpy; 4.7860 mpy and 0.5181 mpy, respectively. While in Limbangan Beach the corrosion rate of specimen carbon steel, galvanized steel and aluminium were 3.339; 0.219 and 0.166 mpy, respectively. The chloride content was found to be the main factor that influences in the atmospheric corrosion process in this area. Chloride content accumulated in Karangsong and Limbangan was 497 mg/m2.day and 117 mg/m2.day, respectively. The XRD Analysis on each carbon steel led to the characterization of a complex mixture of iron oxides phases.

  8. Enabling rootless Linux containers in multi-user environments. The udocker tool

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Jorge; David, Mario; Alves, Luis; Martins, Jo ao; Pina, Jo ao [Laboratorio de Instrumentacao e Fisica Experimental de Particulas (LIP), Lisboa (Portugal); Bagnaschi, Emanuele [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Campos, Isabel; Lopez-Garcia, Alvaro; Orviz, Pablo [IFCA, Consejo Superior de Investigaciones Cientificas-CSIC, Santander (Spain)

    2017-11-15

    Containers are increasingly used as means to distribute and run Linux services and applications. In this paper we describe the architectural design and implementation of udocker a tool to execute Linux containers in user mode and we describe a few practical applications for a range of scientific codes meeting different requirements: from single core execution to MPI parallel execution and execution on GPGPUs.

  9. DICE/ColDICE: 6D collisionless phase space hydrodynamics using a lagrangian tesselation

    Science.gov (United States)

    Sousbie, Thierry

    2018-01-01

    DICE is a C++ template library designed to solve collisionless fluid dynamics in 6D phase space using massively parallel supercomputers via an hybrid OpenMP/MPI parallelization. ColDICE, based on DICE, implements a cosmological and physical VLASOV-POISSON solver for cold systems such as dark matter (CDM) dynamics.

  10. Diagnostic value of transmural perfusion ratio derived from dynamic CT-based myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Coenen, Adriaan; Lubbers, Marisa M.; Dedic, Admir; Chelu, Raluca G.; Geuns, Robert-Jan M. van; Nieman, Koen [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus University Medical Center, Department of Cardiology, Rotterdam (Netherlands); Kurata, Akira; Kono, Atsushi; Dijkshoorn, Marcel L. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Rossi, Alexia [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Barts Health NHS Trust, NIHR Cardiovascular Biomedical Research Unit at Barts, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London and Department of Cardiology, London (United Kingdom)

    2017-06-15

    To investigate the additional value of transmural perfusion ratio (TPR) in dynamic CT myocardial perfusion imaging for detection of haemodynamically significant coronary artery disease compared with fractional flow reserve (FFR). Subjects with suspected or known coronary artery disease were prospectively included and underwent a CT-MPI examination. From the CT-MPI time-point data absolute myocardial blood flow (MBF) values were temporally resolved using a hybrid deconvolution model. An absolute MBF value was measured in the suspected perfusion defect. TPR was defined as the ratio between the subendocardial and subepicardial MBF. TPR and MBF results were compared with invasive FFR using a threshold of 0.80. Forty-three patients and 94 territories were analysed. The area under the receiver operator curve was larger for MBF (0.78) compared with TPR (0.65, P = 0.026). No significant differences were found in diagnostic classification between MBF and TPR with a territory-based accuracy of 77 % (67-86 %) for MBF compared with 70 % (60-81 %) for TPR. Combined MBF and TPR classification did not improve the diagnostic classification. Dynamic CT-MPI-based transmural perfusion ratio predicts haemodynamically significant coronary artery disease. However, diagnostic performance of dynamic CT-MPI-derived TPR is inferior to quantified MBF and has limited incremental value. (orig.)

  11. 75 FR 42455 - Novartis Pharmaceuticals Corp. et al.; Withdrawal of Approval of 27 New Drug Applications and 58...

    Science.gov (United States)

    2010-07-21

    ... Endo Pharmaceuticals NDA 17-255 MPI DTPA Chelate multidose (kit for Medi-Physics, Inc., d/b/a GE... 7.5 mg/750 mg ANDA 40-312 Innofem (estradiol tablets USP), 0.5 Novo Nordisk, Inc., 100 College Rd... Ranbaxy, Inc., U.S. Agent for Ranbaxy Tablets, 1,000 mg Laboratories Limited, 600 College Rd. East...

  12. Lactoferrin conjugated iron oxide nanoparticles for targeting brain glioma cells in magnetic particle imaging

    Science.gov (United States)

    Tomitaka, Asahi; Arami, Hamed; Gandhi, Sonu; Krishnan, Kannan M.

    2015-10-01

    Magnetic Particle Imaging (MPI) is a new real-time imaging modality, which promises high tracer mass sensitivity and spatial resolution directly generated from iron oxide nanoparticles. In this study, monodisperse iron oxide nanoparticles with median core diameters ranging from 14 to 26 nm were synthesized and their surface was conjugated with lactoferrin to convert them into brain glioma targeting agents. The conjugation was confirmed with the increase of the hydrodynamic diameters, change of zeta potential, and Bradford assay. Magnetic particle spectrometry (MPS), performed to evaluate the MPI performance of these nanoparticles, showed no change in signal after lactoferrin conjugation to nanoparticles for all core diameters, suggesting that the MPI signal is dominated by Néel relaxation and thus independent of hydrodynamic size difference or presence of coating molecules before and after conjugations. For this range of core sizes (14-26 nm), both MPS signal intensity and spatial resolution improved with increasing core diameter of nanoparticles. The lactoferrin conjugated iron oxide nanoparticles (Lf-IONPs) showed specific cellular internalization into C6 cells with a 5-fold increase in MPS signal compared to IONPs without lactoferrin, both after 24 h incubation. These results suggest that Lf-IONPs can be used as tracers for targeted brain glioma imaging using MPI.

  13. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  14. Science | AAAS

    Science.gov (United States)

    Giuseppe Conte Italy's new prime minister defended discredited stem cell therapy By Luca Tancredi Barone defended discredited stem cell therapy By Luca Tancredi Barone May. 24, 2018 illustration of GOES-17 | May. 24, 2018 STEPHAN JUNEK/MPI BRAIN RESEARCH Apparatus for building a single NaCs molecule from two

  15. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Author Affiliations. S K Chaudhury1 2 A K Singh1 C S S Sivaramakrishnan1 S C Panigrahi3. National Metallurgical Laboratory, Jamshedpur 831 007, India; 100 Institute Road, MPI, WPI, Worcester, MA 01609, USA; Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721 302, ...

  16. Real-Time Simulation of Ship-Structure and Ship-Ship Interaction

    DEFF Research Database (Denmark)

    Lindberg, Ole; Glimberg, Stefan Lemvig; Bingham, Harry B.

    2013-01-01

    , because it is simple, easy to implement and computationally efficient. Multiple many-core graphical processing units (GPUs) are used for parallel execution and the model is implemented using a combination of C/C++, CUDA and MPI. Two ship hydrodynamic cases are presented: Kriso Container Carrier at steady...

  17. LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome.

    Science.gov (United States)

    Chen, Chun; Li, Dianfu; Miao, Changqing; Feng, Jianlin; Zhou, Yanli; Cao, Kejiang; Lloyd, Michael S; Chen, Ji

    2012-07-01

    The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4%) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI.

  18. Reincarnation of Streaming Applications

    Science.gov (United States)

    2009-10-01

    clear and crisp description of the legacy problem • What should be the scope of SFE? • Should SFE be confined to a single: – Class of programs...Th dM HPM Toolkit (IBM) Jumpshot (Argonne-DOE) Monitor rea on Timescan (Etnus) TRAPPER WARTS MPIMAP (LLNL) mpiP(ORNL/LLNL) Pable/SvPablo( Univ

  19. Minimizing Patient-Specific Tracer Dose in Myocardial Perfusion Imaging Using CZT SPECT

    NARCIS (Netherlands)

    van Dijk, Joris David; Jager, Pieter L.; Ottervanger, Jan Paul; Slump, Cornelis H.; de Boer, Jaep; Oostdijk, Adrianus H.J.; van Dalen, Jorn A.

    Myocardial perfusion imaging (MPI) with SPECT is widely adopted in clinical practice but is associated with a relatively high radiation dose. The aim of this study was to determine the minimum product of tracer dose and scan time that will maintain diagnostic value for cadmium zinc telluride (CZT)

  20. Does Classification of Persons with Fibromyalgia into Multidimensional Pain Inventory Subgroups Detect Differences in Outcome after a Standard Chronic Pain Management Program?

    Directory of Open Access Journals (Sweden)

    Martin L Verra

    2009-01-01

    Full Text Available INTRODUCTION: The present study aimed to replicate and validate the empirically derived subgroup classification based on the Multidimensional Pain Inventory (MPI in a sample of highly disabled fibromyalgia (FM patients. Second, it examined how the identified subgroups differed in their response to an intensive, interdisciplinary inpatient pain management program.

  1. The Mentoring Profile Inventory: An Online Professional Development Resource for Cooperating Teachers

    Science.gov (United States)

    Clarke, Anthony; Collins, John; Triggs, Valerie; Nielsen, Wendy; Augustine, Ann; Coulter, Dianne; Cunningham, Joni; Grigoriadis, Tina; Hardman, Stephanie; Hunter, Lee; Kinegal, Jane; Li, Bianca; Mah, Jeff; Mastin, Karen; Partridge, David; Pawer, Leonard; Rasoda,Sandy; Salbuvik, Kathleen; Ward, Mitch; White, Janet; Weil, Frederick

    2012-01-01

    We report on the origins, development and refinement of an online inventory to help cooperating teachers focus on selected dimensions of their practice. The Mentoring Profile Inventory (MPI) helps quantify important features of both the motivating and challenging aspects of mentoring student teachers and provides results to respondents in a…

  2. Effect of preload alternations on a new Doppler echocardiographic index of combined systolic and diastolic performance

    DEFF Research Database (Denmark)

    Møller, J E; Poulsen, S H; Egstrup, K

    1999-01-01

    The objective of the study was to assess the effect of preload alternations on a nongeometric Doppler index of combined systolic and diastolic myocardial performance (MPI). Doppler echocardiography was performed during Valsalva maneuver, passive leg lifting, and after sublingual administration of...

  3. CORROSION INHIBITION BEHAVIOR OF KETOSULFONE FOR ...

    African Journals Online (AJOL)

    2015-03-31

    Mar 31, 2015 ... resistance and it is expressed in Milli-inches per year (mpy). Polarization resistance is also .... rough and porous electrodes. One is the filmed equivalent ... Fig.4. Electrical Equivalent circuit model used to fit impedance data ...

  4. Multiscale Phase Inversion of Seismic Data

    KAUST Repository

    Fu, Lei; Guo, Bowen; Sun, Yonghe; Schuster, Gerard T.

    2017-01-01

    -skipping, the multiscale strategy temporally integrates the traces several times, i.e. high-order integration, to produce low-boost seismograms that are used as input data for the initial iterations of MPI. As the iterations proceed, higher frequencies in the data

  5. Parallelization of MCNP Monte Carlo neutron and photon transport code in parallel virtual machine and message passing interface

    International Nuclear Information System (INIS)

    Deng Li; Xie Zhongsheng

    1999-01-01

    The coupled neutron and photon transport Monte Carlo code MCNP (version 3B) has been parallelized in parallel virtual machine (PVM) and message passing interface (MPI) by modifying a previous serial code. The new code has been verified by solving sample problems. The speedup increases linearly with the number of processors and the average efficiency is up to 99% for 12-processor. (author)

  6. 3D Plasmonic Ensembles of Graphene Oxide and Nobel Metal Nanoparticles with Ultrahigh SERS Activity and Sensitivity

    Directory of Open Access Journals (Sweden)

    Jing Lin

    2016-01-01

    Full Text Available We describe a comparison study on 3D ensembles of graphene oxide (GO and metal nanoparticles (silver nanoparticles (AgNPs, gold nanoparticles (GNPs, and gold nanorods (GNRs for surface-enhanced Raman scattering (SERS application. For the first time, GNRs were successfully assembled on the surfaces of GO by means of electrostatic interactions without adding any surfactant. The SERS properties of GO/AgNPs, GO/GNPs, and GO/GNRs were compared using 2-mercaptopyridine (2-Mpy as probing molecule. We found that GO/AgNPs and GO/GNPs substrates are not suitable for detecting 2-Mpy due to the very strong π-π stacking interaction between the 2-Mpy molecules and sp2 carbon structure of GO. Conversely, the GO/GNRs substrates show ultrahigh SERS activity and sensitivity of 2-Mpy with the detection limit as low as ~10-15 M, which is ~2-3 orders of magnitude higher than that of the corresponding GNRs.

  7. Quantum Matter : Life beyond symmetries

    Indian Academy of Sciences (India)

    Collaborators. •. Phys. Rev. Lett. 115, 116803 (2015). •. Phys. Rev. Lett. 115, 267209 (2015). •. Phys. Rev. B 93, 195143 (2016). •. arXiv: 1603.05109 (2016). References. • Y. B. Kim, U. Toronto. • K. Dhochak, ICTS. • S. Sanyal, ICTS. • A. Nanda, ICTS. Funding. •. SERB, Early Career Grant. •. MPI-Partner Group ...

  8. Meeting the challenges related to material issues in chemical ...

    Indian Academy of Sciences (India)

    1mpy unit, one thousandth of an inch per year, is used throughout the paper for the convenience of engineering personnel. ..... Platinum and Pt–Ir coatings were prepared by ..... to support the steam-dryer/separator assembly, and the bottom is welded with a flange to ..... spider's web, the abalone shell and the tortoise shell.

  9. A two-dimensional linear elasticity problem for anisotropic materials, solved with a parallelization code

    Directory of Open Access Journals (Sweden)

    Mihai-Victor PRICOP

    2010-09-01

    Full Text Available The present paper introduces a numerical approach of static linear elasticity equations for anisotropic materials. The domain and boundary conditions are simple, to enhance an easy implementation of the finite difference scheme. SOR and gradient are used to solve the resulting linear system. The simplicity of the geometry is also useful for MPI parallelization of the code.

  10. Message Passing Framework for Globally Interconnected Clusters

    International Nuclear Information System (INIS)

    Hafeez, M; Riaz, N; Asghar, S; Malik, U A; Rehman, A

    2011-01-01

    In prevailing technology trends it is apparent that the network requirements and technologies will advance in future. Therefore the need of High Performance Computing (HPC) based implementation for interconnecting clusters is comprehensible for scalability of clusters. Grid computing provides global infrastructure of interconnecting clusters consisting of dispersed computing resources over Internet. On the other hand the leading model for HPC programming is Message Passing Interface (MPI). As compared to Grid computing, MPI is better suited for solving most of the complex computational problems. MPI itself is restricted to a single cluster. It does not support message passing over the internet to use the computing resources of different clusters in an optimal way. We propose a model that provides message passing capabilities between parallel applications over the internet. The proposed model is based on Architecture for Java Universal Message Passing (A-JUMP) framework and Enterprise Service Bus (ESB) named as High Performance Computing Bus. The HPC Bus is built using ActiveMQ. HPC Bus is responsible for communication and message passing in an asynchronous manner. Asynchronous mode of communication offers an assurance for message delivery as well as a fault tolerance mechanism for message passing. The idea presented in this paper effectively utilizes wide-area intercluster networks. It also provides scheduling, dynamic resource discovery and allocation, and sub-clustering of resources for different jobs. Performance analysis and comparison study of the proposed framework with P2P-MPI are also presented in this paper.

  11. On the retrieval of significant wave heights from spaceborne Synthetic Aperture Radar using the Max-Planck Institut algorithm.

    Science.gov (United States)

    Violante-Carvalho, Nelson

    2005-12-01

    Synthetic Aperture Radar (SAR) onboard satellites is the only source of directional wave spectra with continuous and global coverage. Millions of SAR Wave Mode (SWM) imagettes have been acquired since the launch in the early 1990's of the first European Remote Sensing Satellite ERS-1 and its successors ERS-2 and ENVISAT, which has opened up many possibilities specially for wave data assimilation purposes. The main aim of data assimilation is to improve the forecasting introducing available observations into the modeling procedures in order to minimize the differences between model estimates and measurements. However there are limitations in the retrieval of the directional spectrum from SAR images due to nonlinearities in the mapping mechanism. The Max-Planck Institut (MPI) scheme, the first proposed and most widely used algorithm to retrieve directional wave spectra from SAR images, is employed to compare significant wave heights retrieved from ERS-1 SAR against buoy measurements and against the WAM wave model. It is shown that for periods shorter than 12 seconds the WAM model performs better than the MPI, despite the fact that the model is used as first guess to the MPI method, that is the retrieval is deteriorating the first guess. For periods longer than 12 seconds, the part of the spectrum that is directly measured by SAR, the performance of the MPI scheme is at least as good as the WAM model.

  12. Enabling rootless Linux containers in multi-user environments. The udocker tool

    International Nuclear Information System (INIS)

    Gomes, Jorge; David, Mario; Alves, Luis; Martins, Jo ao; Pina, Jo ao; Bagnaschi, Emanuele; Campos, Isabel; Lopez-Garcia, Alvaro; Orviz, Pablo

    2017-11-01

    Containers are increasingly used as means to distribute and run Linux services and applications. In this paper we describe the architectural design and implementation of udocker a tool to execute Linux containers in user mode and we describe a few practical applications for a range of scientific codes meeting different requirements: from single core execution to MPI parallel execution and execution on GPGPUs.

  13. How to Build MCNP 6.2

    Energy Technology Data Exchange (ETDEWEB)

    Bull, Jeffrey S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-13

    This presentation describes how to build MCNP 6.2. MCNP®* 6.2 can be compiled on Macs, PCs, and most Linux systems. It can also be built for parallel execution using both OpenMP and Messing Passing Interface (MPI) methods. MCNP6 requires Fortran, C, and C++ compilers to build the code.

  14. Recent developments in bend-insensitive and ultra-bend-insensitive fibers

    Science.gov (United States)

    Boivin, David; de Montmorillon, Louis-Anne; Provost, Lionel; Montaigne, Nelly; Gooijer, Frans; Aldea, Eugen; Jensma, Jaap; Sillard, Pierre

    2010-02-01

    Designed to overcome the limitations in case of extreme bending conditions, Bend- and Ultra-Bend-Insensitive Fibers (BIFs and UBIFs) appear as ideal solutions for use in FTTH networks and in components, pigtails or patch-cords for ever demanding applications such as military or sensing. Recently, however, questions have been raised concerning the Multi-Path-Interference (MPI) levels in these fibers. Indeed, they are potentially subject to interferences between the fundamental mode and the higher-order mode that is also bend resistant. This MPI is generated because of discrete discontinuities such as staples, bends and splices/connections that occur on distance scales that become comparable to the laser coherent length. In this paper, we will demonstrate the high MPI tolerance of all-solid single-trench-assisted BIFs and UBIFs. We will present the first comprehensive study combining theoretical and experimental points of view to quantify the impact of fusion splices on coherent MPI. To be complete, results for mechanical splices will also be reported. Finally, we will show how the single-trench- assisted concept combined with the versatile PCVD process allows to tightly control the distributions of fibers characteristics. Such controls are needed to massively produce BIFs and to meet the more stringent specifications of the UBIFs.

  15. Massively parallel and linear-scaling algorithm for second-order Møller–Plesset perturbation theory applied to the study of supramolecular wires

    DEFF Research Database (Denmark)

    Kjærgaard, Thomas; Baudin, Pablo; Bykov, Dmytro

    2017-01-01

    We present a scalable cross-platform hybrid MPI/OpenMP/OpenACC implementation of the Divide–Expand–Consolidate (DEC) formalism with portable performance on heterogeneous HPC architectures. The Divide–Expand–Consolidate formalism is designed to reduce the steep computational scaling of conventiona...

  16. Performance Benchmarking of Fast Multipole Methods

    KAUST Repository

    Al-Harthi, Noha A.

    2013-01-01

    The current trends in computer architecture are shifting towards smaller byte/flop ratios, while available parallelism is increasing at all levels of granularity – vector length, core count, and MPI process. Intel’s Xeon Phi coprocessor, NVIDIA’s

  17. Corrosion Inhibition of Cold-rolled Low Carbon Steel with Pulse Fiber Laser Ablation in Water

    Science.gov (United States)

    Chan, Sze Ney; Wong, Wai Yin; Walvekar, Rashmi; Kadhum, Abdul Amir H.; Khalid, Mohammad; Lim, Kean Long

    2018-04-01

    This study aims at the use of a fiber laser for modifying the surface properties of cold-rolled low carbon steel via a pulse laser ablation technique in water. The effect on the corrosion behavior of the fiber laser-treated metal surface was investigated in NaCl and HCl environments. Electrochemical tests showed significant improvement in the corrosion resistance of the laser-treated sample in NaCl, with an increase in open-circuit potential (OCP) from - 0.65 to - 0.60 V and an inhibition efficiency of 89.22% as obtained from the impedance study. Such improvement was less significant in an acidic environment. Lower corrosion rates of 20.9 mpy and 5.819 × 103 mpy were obtained for the laser-treated samples in neutral and acidic electrolytes, respectively, than the corrosion rates obtained for the as-received samples (33.2 mpy and 11.98 × 103 mpy). Morphological analysis indicated a passive film built by spherical grains of regular size on the metal surface after laser treatment. The corrosion inhibition effects in NaCl were evident by the nonexistence of the common corrosion products of lepidocrocite and crystalline structures that were seen on as-received samples; only polyhedral crystals with micrograins grown on them were seen covering the laser-treated surface. Therefore, the laser treatment using a fiber laser source improved the corrosion resistance of cold-rolled low carbon steel.

  18. Responsiveness of five condition-specific and generic outcome assessment instruments for chronic pain

    Directory of Open Access Journals (Sweden)

    Verra Martin L

    2008-04-01

    Full Text Available Abstract Background Changes of health and quality-of-life in chronic conditions are mostly small and require specific and sensitive instruments. The aim of this study was to determine and compare responsiveness, i.e. the sensitivity to change of five outcome instruments for effect measurement in chronic pain. Methods In a prospective cohort study, 273 chronic pain patients were assessed on the Numeric Rating Scale (NRS for pain, the Short Form 36 (SF-36, the Multidimensional Pain Inventory (MPI, the Hospital Anxiety and Depression Scale (HADS, and the Coping Strategies Questionnaire (CSQ. Responsiveness was quantified by effect size (ES and standardized response mean (SRM before and after a four week in-patient interdisciplinary pain program and compared by the modified Jacknife test. Results The MPI measured pain more responsively than the SF-36 (ES: 0.85 vs 0.72, p = 0.053; SRM: 0.72 vs 0.60, p = 0.027 and the pain NRS (ES: 0.85 vs 0.62, p Conclusion The MPI was most responsive in all comparable domains followed by the SF-36. The pain-specific MPI and the generic SF-36 can be recommended for comprehensive and specific bio-psycho-social effect measurement of health and quality-of-life in chronic pain.

  19. High Performance Computing Multicast

    Science.gov (United States)

    2012-02-01

    A History of the Virtual Synchrony Replication Model,” in Replication: Theory and Practice, Charron-Bost, B., Pedone, F., and Schiper, A. (Eds...Performance Computing IP / IPv4 Internet Protocol (version 4.0) IPMC Internet Protocol MultiCast LAN Local Area Network MCMD Dr. Multicast MPI

  20. Multidimensional Poverty Indices and First Order Dominance Techniques: An Empirical Comparison of Different Approaches

    DEFF Research Database (Denmark)

    Hussain, M. Azhar; Permanyer, Iñaki

    2018-01-01

    techniques (FOD). Our empirical findings suggest that the FOD approach might be a reasonable cost-effective alternative to the United Nations Development Program (UNDP)’s flagship poverty indicator: the Multidimensional Poverty Index (MPI). To the extent that the FOD approach is able to uncover the socio...

  1. A lightweight communication library for distributed computing

    NARCIS (Netherlands)

    Groen, D.; Rieder, S.; Grosso, P.; de Laat, C.; Portegies Zwart, S.

    2010-01-01

    We present MPWide, a platform-independent communication library for performing message passing between computers. Our library allows coupling of several local message passing interface (MPI) applications through a long-distance network and is specifically optimized for such communications. The

  2. LUCKY-TD code for solving the time-dependent transport equation with the use of parallel computations

    Energy Technology Data Exchange (ETDEWEB)

    Moryakov, A. V., E-mail: sailor@orc.ru [National Research Centre Kurchatov Institute (Russian Federation)

    2016-12-15

    An algorithm for solving the time-dependent transport equation in the P{sub m}S{sub n} group approximation with the use of parallel computations is presented. The algorithm is implemented in the LUCKY-TD code for supercomputers employing the MPI standard for the data exchange between parallel processes.

  3. Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems.

    Science.gov (United States)

    Shehzad, Danish; Bozkuş, Zeki

    2016-01-01

    Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA) by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models.

  4. Dynamic CT perfusion imaging of the myocardium: a technical note on improvement of image quality.

    Directory of Open Access Journals (Sweden)

    Daniela Muenzel

    Full Text Available OBJECTIVE: To improve image and diagnostic quality in dynamic CT myocardial perfusion imaging (MPI by using motion compensation and a spatio-temporal filter. METHODS: Dynamic CT MPI was performed using a 256-slice multidetector computed tomography scanner (MDCT. Data from two different patients-with and without myocardial perfusion defects-were evaluated to illustrate potential improvements for MPI (institutional review board approved. Three datasets for each patient were generated: (i original data (ii motion compensated data and (iii motion compensated data with spatio-temporal filtering performed. In addition to the visual assessment of the tomographic slices, noise and contrast-to-noise-ratio (CNR were measured for all data. Perfusion analysis was performed using time-density curves with regions-of-interest (ROI placed in normal and hypoperfused myocardium. Precision in definition of normal and hypoperfused areas was determined in corresponding coloured perfusion maps. RESULTS: The use of motion compensation followed by spatio-temporal filtering resulted in better alignment of the cardiac volumes over time leading to a more consistent perfusion quantification and improved detection of the extend of perfusion defects. Additionally image noise was reduced by 78.5%, with CNR improvements by a factor of 4.7. The average effective radiation dose estimate was 7.1±1.1 mSv. CONCLUSION: The use of motion compensation and spatio-temporal smoothing will result in improved quantification of dynamic CT MPI using a latest generation CT scanner.

  5. Scalable Algorithms for Parallel Discrete Event Simulation Systems in Multicore Environments

    Science.gov (United States)

    2013-05-01

    consolidated at the sender side. At the receiver side, the messages are deconsolidated and delivered to the appropriate thread. This approach bears some...Jiang, S. Kini, W. Yu, D. Buntinas, P. Wyckoff, and D. Panda . Performance comparison of mpi implementations over infiniband, myrinet and quadrics

  6. Incremental value of contrast myocardial perfusion to detect intermediate versus severe coronary artery stenosis during stress-echocardiography

    Directory of Open Access Journals (Sweden)

    Ugo Fabrizio

    2010-05-01

    Full Text Available Abstract Background We aimed to compare the incremental value of contrast myocardial perfusion imaging (MPI for the detection of intermediate versus severe coronary artery stenosis during dipyridamole-atropine echocardiography (DASE. Wall motion (WM assessment during stress-echocardiography demonstrates suboptimal sensitivity to detect coronary artery disease (CAD, particularly in patients with isolated intermediate (50%-70% coronary stenosis. Methods We performed DASE with MPI in 150 patients with a suspected chest pain syndrome who were given clinical indication to coronary angiography. Results and discussion When CAD was defined as the presence of a ≥50% stenosis, the addition of MPI increased sensitivity (+30% and decreased specificity (-14%, with a final increase in total diagnostic accuracy (+16%, p Conclusions The addition of MPI on top of WM analysis during DASE increases the diagnostic sensitivity to detect obstructive CAD, whatever its definition (≥50% or > 70% stenosis, but it is mainly driven by the sensitivity increase in the intermediate group (50%-70% stenosis. The total diagnostic accuracy increased only when defining CAD as ≥50% stenosis, since in patients with severe stenosis (> 70% the decrease in specificity is not counterbalanced by the minor sensitivity increase.

  7. The value of regional wall motion abnormalities on gated mycardiac perfusion imaging in perfusion imaging in predicting angiographic stenoses of coronary artery

    International Nuclear Information System (INIS)

    Yao Lixin; Liu Binbin

    2007-01-01

    Objective: To determine the possible level of angiographic stenoses of coronary artery at which reversible regional wall motion abnormalities (RWMA) are present on 99m Tc-sestamibi ( 99m Tc-MIBI)-gated myocardial perfusion imaging (MPI). Methods: ninty patients undergoing coronary angiography MPI within two weeks were recruited. A five grades and nine segments marking system was introduced to assess the RWMA and thickening of left ventricles. Results: The sensitivity of reversible RWMA for detecting ≥75% angiographic stenoses was 64%,with a specificity of 95% and positive predictive value of 97%. The presence of reversible RWMA was able to stratify patients with severe angiographic stenoses of 75% or more from those less than 75% with high positive predictive value. A good correlation was noted between the presence of reversible RWMA and the coronary artery jeopardy score. Multivariate analysis showed that the post-stress RWMA and reversible RWMA scores and positive dipyridamole-stress exercise electrocardiogram(ECG) were significant predictors of angiographic severity. Conclusions: Reversible RWMA, as shown by dipyridamole stress 99m Tc-MIBI MPI, is a significant predictor of angiographic disease with very high specificity and adds incremental value to MPI for the assessment of angiographic severity. (authors)

  8. The value of regional wall motion abnormalities on 99Tcm-MIBI gated cardiac SPECT in predicting angiographic stenoses of coronary artery

    International Nuclear Information System (INIS)

    Li Dianfu; Huang Jun; Zhu Tiebing; Wang Liansheng; Yang Zhijian; Feng Jianlin; Li Jianhua; Chen Jianwei; Chang Guojun

    2004-01-01

    Objective: To determine the magnitude of angiographic stenoses of coronary artery in reversible regional wall motion abnormalities (RWMA) present in exercise stress 99 Tc m -methoxyisobutylisonitrile (MIBI) gated SPECT myocardial perfusion imaging (MPI). Methods: One hundred and sixteen patients undergoing coronary angiography two weeks before and after the exercise stress 99 Tc m -MIBI gated SPECT MPI. Images were acquired 15 to 20 min after stress. A five grades and twenty segments marking system was introduced to assess the RWMA and thickening of left ventricles. Results: The sensitivity of reversible RWMA for detecting ≥75% angiographic stenoses was 65%, with a specificity of 97%. Reversible RWMA has a high positive predictive value (98%) for stratification between severe angiographic stenoses of 75% and non-severe stenoses (less than 75%). Multivariate analysis showed that the post-stress wall motion (SSSWM), exercise wall motion differentiation value (SDSWM) and summed stress score (SSS) were the independent risk factor of coronary artery jeopardy score. Conclusions: Reversible RWMA, as shown by exercise stress 99 Tc m -MIBI gated SPECT MPI, is a significant predictor of angiographic disease with very high specificity and positive predictive values. Exercise reversible RWMA can rise the assessment value of angiographic severity in MPI

  9. Resource-Efficient, Hierarchical Auto-Tuning of a Hybrid Lattice Boltzmann Computation on the Cray XT4

    International Nuclear Information System (INIS)

    Williams, Samuel; Carter, Jonathan; Oliker, Leonid; Shalf, John; Yelick, Katherine

    2009-01-01

    We apply auto-tuning to a hybrid MPI-pthreads lattice Boltzmann computation running on the Cray XT4 at National Energy Research Scientific Computing Center (NERSC). Previous work showed that multicore-specific auto-tuning can improve the performance of lattice Boltzmann magnetohydrodynamics (LBMHD) by a factor of 4x when running on dual- and quad-core Opteron dual-socket SMPs. We extend these studies to the distributed memory arena via a hybrid MPI/pthreads implementation. In addition to conventional auto-tuning at the local SMP node, we tune at the message-passing level to determine the optimal aspect ratio as well as the correct balance between MPI tasks and threads per MPI task. Our study presents a detailed performance analysis when moving along an isocurve of constant hardware usage: fixed total memory, total cores, and total nodes. Overall, our work points to approaches for improving intra- and inter-node efficiency on large-scale multicore systems for demanding scientific applications

  10. A matrix free, partitioned solution of fluid-structure interaction problems using finite volume and finite element methods

    CSIR Research Space (South Africa)

    Suliman, Ridhwaan

    2015-01-01

    Full Text Available . The solver is parallelised for distributed-memory systems using METIS for domaindecomposition and MPI for inter-domain communication. The developed technology is evaluated by application to benchmark problems for strongly-coupled fluid-structure interaction...

  11. Совмещённая процедура сборки матрицы жёсткости при решении упругопластической задачи на кластерной системе

    OpenAIRE

    Толмачев, А. В.; Халевицкий, Ю. В.; Коновалов, А. В.

    2014-01-01

    Finiteelementmethodiswidelyusedinmetalformingprocessessimulation. Parallel implementation of this method on computer cluster raises anissue of parallel stiffness matrix assembly. This paper describes a novel approach to data transmission handling during assembly steps.Advanced techniquessuch ascomputation and communication interleaving and implicit synchronization are used. Authors introduce additional bufferization to hide MPI latency and reduce memory usage.

  12. Comparative efficiencies of three parallel algorithms for nonlinear ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    This algorithm is better suited for large size problems on coarse ... and reliable time integration algorithms for solving the second-order dynamic equilibrium equations that arise due ... Programming models required to take advantage of the parallel and distributed ..... In addition, MPI added the concept of a 'virtual topology'.

  13. Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

    Science.gov (United States)

    Ishihara, Masaru; Onoguchi, Masahisa; Taniguchi, Yasuyo; Shibutani, Takayuki

    2017-12-01

    The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

  14. Implementing parallel elliptic solver on a Beowulf cluster

    Directory of Open Access Journals (Sweden)

    Marcin Paprzycki

    1999-12-01

    Full Text Available In a recent paper cite{zara} a parallel direct solver for the linear systems arising from elliptic partial differential equations has been proposed. The aim of this note is to present the initial evaluation of the performance characteristics of this algorithm on Beowulf-type cluster. In this context the performance of PVM and MPI based implementations is compared.

  15. Parallel Algorithm for Solving TOV Equations for Sequence of Cold and Dense Nuclear Matter Models

    Science.gov (United States)

    Ayriyan, Alexander; Buša, Ján; Grigorian, Hovik; Poghosyan, Gevorg

    2018-04-01

    We have introduced parallel algorithm simulation of neutron star configurations for set of equation of state models. The performance of the parallel algorithm has been investigated for testing set of EoS models on two computational systems. It scales when using with MPI on modern CPUs and this investigation allowed us also to compare two different types of computational nodes.

  16. The Value of Attenuation Correction in Hybrid Cardiac SPECT/CT on Inferior Wall According to Body Mass Index

    International Nuclear Information System (INIS)

    Tamam, Muge; Mulazimoglu, Mehmet; Edis, Nurcan; Ozpacaci, Tevfik

    2016-01-01

    The purpose of this study was to evaluate the diagnostic value of attenuation-corrected single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) on the inferior wall compared to uncorrected (NC) SPECT MPI between obese and nonobese patients. A total of 157 consecutive patients (122 males and 35 females, with median age: 57.4 ± 11 years) who underwent AC technetium 99m-methoxyisobutylisonitrile (AC Tc99m-sestamibi) SPECT MPI were included to the study. A hybrid SPECT and transmission computed tomography (CT) system was used for the diagnosis with 1-day protocol, and stress imaging was performed first. During attenuation correction (AC) processing on a Xeleris Workstation using Myovation cardiac software with ordered subset expectation maximization (OSEM), iterative reconstruction with attenuation correction (IRAC) and NC images filtered back projection (FBP) were used. For statistical purposes, P < 0.05 was considered significant. This study included 73 patients with body mass index (BMI) <30 and 84 patients with BMI ≥ 30. In patients with higher BMI, increased amount of both visual and semiquantitative attenuation of the inferior wall was detected. IRAC reconstruction corrects the diaphragm attenuation of the inferior wall better than FBP. AC with OSEM iterative reconstruction significantly improves the diagnostic value of stress-only SPECT MPI in patients with normal weight and those who are obese, but the improvements are significantly greater in obese patients. Stress-only SPECT imaging with AC provides shorter and lower radiation exposure

  17. Competitive kinetics as a tool to determine rate constants for reduction of ferrylmyoglobin by food components

    DEFF Research Database (Denmark)

    Jongberg, Sisse; Lund, Marianne Nissen; Pattison, David I.

    2016-01-01

    Competitive kinetics were applied as a tool to determine apparent rate constants for the reduction of hypervalent haem pigment ferrylmyoglobin (MbFe(IV)=O) by proteins and phenols in aqueous solution of pH 7.4 and I = 1.0 at 25 °C. Reduction of MbFe(IV)=O by a myofibrillar protein isolate (MPI) f...

  18. MPIRUN: A Portable Loader for Multidisciplinary and Multi-Zonal Applications

    Science.gov (United States)

    Fineberg, Samuel A.; Woodrow, Thomas S. (Technical Monitor)

    1994-01-01

    Multidisciplinary and multi-zonal applications are an important class of applications in the area of Computational Aerosciences. In these codes, two or more distinct parallel programs or copies of a single program are utilized to model a single problem. To support such applications, it is common to use a programming model where a program is divided into several single program multiple data stream (SPMD) applications, each of which solves the equations for a single physical discipline or grid zone. These SPMD applications are then bound together to form a single multidisciplinary or multi-zonal program in which the constituent parts communicate via point-to-point message passing routines. One method for implementing the message passing portion of these codes is with the new Message Passing Interface (MPI) standard. Unfortunately, this standard only specifies the message passing portion of an application, but does not specify any portable mechanisms for loading an application. MPIRUN was developed to provide a portable means for loading MPI programs, and was specifically targeted at multidisciplinary and multi-zonal applications. Programs using MPIRUN for loading and MPI for message passing are then portable between all machines supported by MPIRUN. MPIRUN is currently implemented for the Intel iPSC/860, TMC CM5, IBM SP-1 and SP-2, Intel Paragon, and workstation clusters. Further, MPIRUN is designed to be simple enough to port easily to any system supporting MPI.

  19. Development and Validation of Multi-Dimensional Personality ...

    African Journals Online (AJOL)

    This study was carried out to establish the scientific processes for the development and validation of Multi-dimensional Personality Inventory (MPI). The process of development and validation occurred in three phases with five components of Agreeableness, Conscientiousness, Emotional stability, Extroversion, and ...

  20. A computational test facility for distributed analysis of gravitational wave signals

    International Nuclear Information System (INIS)

    Amico, P; Bosi, L; Cattuto, C; Gammaitoni, L; Punturo, M; Travasso, F; Vocca, H

    2004-01-01

    In the gravitational wave detector Virgo, the in-time detection of a gravitational wave signal from a coalescing binary stellar system is an intensive computational task. A parallel computing scheme using the message passing interface (MPI) is described. Performance results on a small-scale cluster are reported

  1. Cardiac Time Intervals by Tissue Doppler Imaging M-Mode

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; de Knegt, Martina Chantal

    2016-01-01

    PURPOSE: To define normal values of the cardiac time intervals obtained by tissue Doppler imaging (TDI) M-mode through the mitral valve (MV). Furthermore, to evaluate the association of the myocardial performance index (MPI) obtained by TDI M-mode (MPITDI) and the conventional method of obtaining...

  2. Institute for Defense Analysis. Annual Report 1995.

    Science.gov (United States)

    1995-01-01

    staff have been involved in the community-wide development of MPI as well as in its application to specific NSA problems. 35 Parallel Groebner ...Basis Code — Symbolic Computing on Parallel Machines The Groebner basis method is a set of algorithms for reformulating very complex algebraic expres

  3. Myocardial perfusion imaging for predicting cardiac events in Japanese patients with advanced chronic kidney disease: 1-year interim report of the J-ACCESS 3 investigation

    Energy Technology Data Exchange (ETDEWEB)

    Joki, Nobuhiko; Hase, Hiroki [Toho University Ohashi Medical Center, Department of Nephrology, Tokyo (Japan); Kawano, Yuhei; Nakamura, Satoko [National Cerebral and Cardiovascular Center, Division of Hypertension and Nephrology, Osaka (Japan); Nakajima, Kenichi [Kanazawa University Hospital, Department of Nuclear Medicine, Kanazawa (Japan); Hatta, Tsuguru [Hatta Medical Office of Internal Medicine, Kyoto (Japan); Nishimura, Shigeyuki [Saitama Medical University International Medical Center, Saitama (Japan); Moroi, Masao [Toho University Ohashi Medical Center, Department of Cardiology, Tokyo (Japan); Nakagawa, Susumu [Saiseikai Central Hospital, Department of Cardiology, Tokyo (Japan); Kasai, Tokuo [Tokyo Medical University Hachioji Medical Center, Tokyo (Japan); Kusuoka, Hideo [Osaka National Hospital, Osaka (Japan); Takeishi, Yasuchika [Fukushima Medical University, Department of Cardiology and Hematology, Fukushima (Japan); Momose, Mitsuru [Tokyo Women' s Medical University, Department of Diagnostic Imaging and Nuclear Medicine, Tokyo (Japan); Takehana, Kazuya [Kansai Medical University, Department of Cardiology, Osaka (Japan); Nanasato, Mamoru [Cardiovascular Center, Nagoya Daini Red Cross Hospital, Nagoya (Japan); Yoda, Shunichi [Nihon University Itabashi Hospital, Department of Cardiology, Tokyo (Japan); Nishina, Hidetaka [Tsukuba Medical Center Hospital, Department of Cardiology, Tsukuba (Japan); Matsumoto, Naoya [Suruga-dai Nihon University Hospital, Department of Cardiology, Tokyo (Japan); Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto (Japan)

    2014-09-15

    Whether myocardial perfusion imaging (MPI) can predict cardiac events in patients with advanced conservative chronic kidney disease (CKD) remains unclear. The present multicenter prospective cohort study aimed to clarify the ability of MPI to predict cardiac events in 529 patients with CKD and estimated glomerular filtration rates (eGFR) < 50 ml/min per 1.73{sup 2} without a definitive diagnosis of coronary artery disease. All patients were assessed by stress-rest MPI with {sup 99m}Tc-tetrofosmin and analyzed using summed defect scores and QGS software. Cardiac events were analyzed 1 year after registration. Myocardial perfusion abnormalities defined as summed stress score (SSS) ≥4 and ≥8 were identified in 19 and 7 % of patients, respectively. At the end of the 1-year follow-up, 33 (6.2 %) cardiac events had occurred that included cardiac death, sudden death, nonfatal myocardial infarction, and hospitalization due to heart failure. The event-free rates at that time were 0.95, 0.90, and 0.81 for groups with SSS 0-3, 4-7, and ≥8, respectively (p = 0.0009). Thus, patients with abnormal SSS had a higher incidence of cardiac events. Multivariate Cox regression analysis showed that SSS significantly impacts the prediction of cardiac events independently of eGFR and left ventricular ejection fraction. MPI would be useful to stratify patients with advanced conservative CKD who are at high risk of cardiac events without adversely affecting damaged kidneys. (orig.)

  4. Slew-rate dependence of tracer magnetization response in magnetic particle imaging

    Science.gov (United States)

    Shah, Saqlain A.; Ferguson, R. M.; Krishnan, K. M.

    2014-10-01

    Magnetic Particle Imaging (MPI) is a new biomedical imaging technique that produces real-time, high-resolution tomographic images of superparamagnetic iron oxide nanoparticle tracers. Currently, 25 kHz and 20 mT/μ0 excitation fields are common in MPI, but lower field amplitudes may be necessary for patient safety in future designs. Here, we address fundamental questions about MPI tracer magnetization dynamics and predict tracer performance in future scanners that employ new combinations of excitation field amplitude (Ho) and frequency (ω). Using an optimized, monodisperse MPI tracer, we studied how several combinations of drive field frequencies and amplitudes affect the tracer's response, using Magnetic Particle Spectrometry and AC hysteresis, for drive field conditions at 15.5, 26, and 40.2 kHz, with field amplitudes ranging from 7 to 52 mT/μ0. For both fluid and immobilized nanoparticle samples, we determined that magnetic response was dominated by Néel reversal. Furthermore, we observed that the peak slew-rate (ωHo) determined the tracer magnetic response. Smaller amplitudes provided correspondingly smaller field of view, sometimes resulting in excitation of minor hysteresis loops. Changing the drive field conditions but keeping the peak slew-rate constant kept the tracer response almost the same. Higher peak slew-rates led to reduced maximum signal intensity and greater coercivity in the tracer response. Our experimental results were in reasonable agreement with Stoner-Wohlfarth model based theories.

  5. A comparative electrochemical study of electrosorbed 2- and 4 ...

    Indian Academy of Sciences (India)

    Administrator

    4 Mpy due to the formation of a S–Au–N chelate. The under- and .... 0⋅76 V indicat- ing gold hydroxide and oxide formation, which ..... Figure 11 shows the complex plane plot of a C60 .... Chailapakul O, Sun L, Xu C and Crooks R M 1993 J.

  6. Distributed multiscale computing with MUSCLE 2, the Multiscale Coupling Library and Environment

    NARCIS (Netherlands)

    Borgdorff, J.; Mamonski, M.; Bosak, B.; Kurowski, K.; Ben Belgacem, M.; Chopard, B.; Groen, D.; Coveney, P.V.; Hoekstra, A.G.

    2014-01-01

    We present the Multiscale Coupling Library and Environment: MUSCLE 2. This multiscale component-based execution environment has a simple to use Java, C++, C, Python and Fortran API, compatible with MPI, OpenMP and threading codes. We demonstrate its local and distributed computing capabilities and

  7. Multiscale phase inversion of seismic marine data

    KAUST Repository

    Fu, Lei

    2017-01-01

    -boost seismograms that are used as input data for the initial iterations of MPI. As the iterations proceed, higher frequencies in the data are boosted by using integrated traces of lower order as the input data. Results with synthetic data and field data from

  8. Multidimensional poverty dynamics in Ethiopia: how do they differ ...

    African Journals Online (AJOL)

    Poverty can take many different forms, ranging widely over dimensions both monetary, such as consumption or income, and nonmonetary, such as health and education. One large class of nonmonetary measures of poverty is the multidimensional poverty index (MPI); recent studies document that people identified as poor ...

  9. Annual report 1980 of the Institut fuer Physik of the Max-Planck-Institut fuer Physik und Astrophysik, Muenchen

    International Nuclear Information System (INIS)

    1980-12-01

    In this annual report the fields of research done at the MPI for Physics and Astrophysics are summarized. These concern mainly high energy physics. The theoretical work deals with field theory with special regards to unified gauge theories while the Institute contributes to some experiments at DESY and CERN. Furthermore, a list of publications and theses is given. (HSI)

  10. Serial Doppler echocardiographic assessment of left and right ventricular performance after a first myocardial infarction

    DEFF Research Database (Denmark)

    Møller, J E; Søndergaard, E; Poulsen, S H

    2001-01-01

    We sought to investigate the relation between left ventricular (LV) and right ventricular (RV) function assessed with the Doppler-derived myocardial performance index (MPI), to assess serial changes, and to investigate the prognostic value of biventricular assessment of cardiac function after a f...

  11. Student Personality Differences Are Related to Their Responses on Instructor Evaluation Forms

    Science.gov (United States)

    McCann, Stewart; Gardner, Christopher

    2014-01-01

    The relation of student personality to student evaluations of teaching (SETs) was determined in a sample of 144 undergraduates. Student Big Five personality variables and core self-evaluation (CSE) were assessed. Students rated their most preferred instructor (MPI) and least preferred instructor (LPI) on 11 common evaluation items. Pearson and…

  12. Projection x-space magnetic particle imaging.

    Science.gov (United States)

    Goodwill, Patrick W; Konkle, Justin J; Zheng, Bo; Saritas, Emine U; Conolly, Steven M

    2012-05-01

    Projection magnetic particle imaging (MPI) can improve imaging speed by over 100-fold over traditional 3-D MPI. In this work, we derive the 2-D x-space signal equation, 2-D image equation, and introduce the concept of signal fading and resolution loss for a projection MPI imager. We then describe the design and construction of an x-space projection MPI scanner with a field gradient of 2.35 T/m across a 10 cm magnet free bore. The system has an expected resolution of 3.5 × 8.0 mm using Resovist tracer, and an experimental resolution of 3.8 × 8.4 mm resolution. The system images 2.5 cm × 5.0 cm partial field-of views (FOVs) at 10 frames/s, and acquires a full field-of-view of 10 cm × 5.0 cm in 4 s. We conclude by imaging a resolution phantom, a complex "Cal" phantom, mice injected with Resovist tracer, and experimentally confirm the theoretically predicted x-space spatial resolution.

  13. Finite magnetic relaxation in x-space magnetic particle imaging: Comparison of measurements and ferrohydrodynamic models.

    Science.gov (United States)

    Dhavalikar, R; Hensley, D; Maldonado-Camargo, L; Croft, L R; Ceron, S; Goodwill, P W; Conolly, S M; Rinaldi, C

    2016-08-03

    Magnetic Particle Imaging (MPI) is an emerging tomographic imaging technology that detects magnetic nanoparticle tracers by exploiting their non-linear magnetization properties. In order to predict the behavior of nanoparticles in an imager, it is possible to use a non-imaging MPI relaxometer or spectrometer to characterize the behavior of nanoparticles in a controlled setting. In this paper we explore the use of ferrohydrodynamic magnetization equations for predicting the response of particles in an MPI relaxometer. These include a magnetization equation developed by Shliomis (Sh) which has a constant relaxation time and a magnetization equation which uses a field-dependent relaxation time developed by Martsenyuk, Raikher and Shliomis (MRSh). We compare the predictions from these models with measurements and with the predictions based on the Langevin function that assumes instantaneous magnetization response of the nanoparticles. The results show good qualitative and quantitative agreement between the ferrohydrodynamic models and the measurements without the use of fitting parameters and provide further evidence of the potential of ferrohydrodynamic modeling in MPI.

  14. Regadenoson

    Directory of Open Access Journals (Sweden)

    G M Bengalorkar

    2012-01-01

    Full Text Available Single-photon emission computerized tomography for myocardial perfusion imaging (MPI is a non-invasive technique. MPI is performed by subjecting the patient to exercise or by using a pharmacological stress agent. Regadenoson is a selective A 2A adenosine receptor agonist used when MPI with exercise is contraindicated. It binds to the A 2A receptor and stimulates adenylate cyclase, resulting in increased cAMP, which phosphorylates protein kinase A thereby opening the ATP-dependant potassium channels leading to hyperpolarization in the coronary vascular smooth muscle. After a single bolus dose of regadenoson 400 μg, a peak plasma concentration (C max of 13.6 ng/mL is attained in 1-4 min, with a terminal half-life of 2 h. It has a quick onset, short duration sufficient enough for hyperemic response, with comparable efficacy to adenosine, but with fewer side-effects. The adverse effects of this drug are dyspnea, headache, flushing, chest pain and atrioventricular block. Regadenoson is used for MPI in patients with co-morbid conditions like mild-to-moderate reactive airway disease, obstructive lung disease and renal impairment.

  15. Prediction of cardiac events in patients with transient left ventricle dilation on stress myocardial perfusion SPECT images

    International Nuclear Information System (INIS)

    Fukuda, Hiroshi; Moroi, Masao

    2005-01-01

    The purpose of this study was to investigate cardiac events in patients with transient left ventricle (LV) dilation on stress myocardial perfusion single-photon emission computed tomography images (MPI). Consecutive patients (n=53, 31 males, mean age 71 years) with transient LV dilation on thallium-201 stress MPI (treadmill: 21, pharmacologic: 32) were followed for 17 months. Follow-up time was censored at the occurrence of cardiac death, congestive heart failure, acute coronary syndrome, or revascularization. Images were scored and then the summed stress score (SSS), summed rest score, and summed difference score were calculated. Cardiac death occurred in 3 patients, hospitalization occurred in 8 patients, and revascularization occurred in 20 patients. The combined cardiac event rate was 59% (76% for exercise stress vs 47% for pharmacologic stress, p=0.034.). Cox regression analysis demonstrated that a combination of higher SSS and slow washout rate was the best predictor of cardiac events (hazard ratio=3.3, p=0.029). A high cardiac event rate is associated with transient LV dilation on thallium-201 stress MPI. The event rate is particularly high for exercise stress MPI. Furthermore, a combination of the SSS and thallium-201 slow washout is the best predictor of cardiac events in patients with transient LV dilation. (author)

  16. Diagnostic value of thallium-201 myocardial perfusion IQ-SPECT without and with computed tomography-based attenuation correction to predict clinically significant and insignificant fractional flow reserve

    Science.gov (United States)

    Tanaka, Haruki; Takahashi, Teruyuki; Ohashi, Norihiko; Tanaka, Koichi; Okada, Takenori; Kihara, Yasuki

    2017-01-01

    Abstract The aim of this study was to clarify the predictive value of fractional flow reserve (FFR) determined by myocardial perfusion imaging (MPI) using thallium (Tl)-201 IQ-SPECT without and with computed tomography-based attenuation correction (CT-AC) for patients with stable coronary artery disease (CAD). We assessed 212 angiographically identified diseased vessels using adenosine-stress Tl-201 MPI-IQ-SPECT/CT in 84 consecutive, prospectively identified patients with stable CAD. We compared the FFR in 136 of the 212 diseased vessels using visual semiquantitative interpretations of corresponding territories on MPI-IQ-SPECT images without and with CT-AC. FFR inversely correlated most accurately with regional summed difference scores (rSDS) in images without and with CT-AC (r = −0.584 and r = −0.568, respectively, both P system can predict FFR at an optimal cut-off of <0.80, and we propose a novel application of CT-AC to MPI-IQ-SPECT for predicting clinically significant and insignificant FFR even in nonobese patients. PMID:29390486

  17. High performance shallow water kernels for parallel overland flow simulations based on FullSWOF2D

    KAUST Repository

    Wittmann, Roland; Bungartz, Hans-Joachim; Neumann, Philipp

    2017-01-01

    -by-step transformation of the second order finite volume scheme in FullSWOF2D towards MPI parallelization. Second, the computational kernels are optimized by the use of templates and a portable vectorization approach. We discuss the load imbalance of the flux computation

  18. Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems

    Directory of Open Access Journals (Sweden)

    Danish Shehzad

    2016-01-01

    Full Text Available Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models.

  19. Scaling up machine learning: parallel and distributed approaches

    National Research Council Canada - National Science Library

    Bekkerman, Ron; Bilenko, Mikhail; Langford, John

    2012-01-01

    ... presented in the book cover a range of parallelization platforms from FPGAs and GPUs to multi-core systems and commodity clusters; concurrent programming frameworks that include CUDA, MPI, MapReduce, and DryadLINQ; and various learning settings: supervised, unsupervised, semi-supervised, and online learning. Extensive coverage of parallelizat...

  20. Neural Correlates of the Y Chromosome in Autism: XYY Syndrome as a Genetic Model

    Science.gov (United States)

    2017-09-01

    are to describe the natural history of young children with SCT from infancy to 5 years, with a focus on early predictors of neurodevelopmental and...will function as one component of the overall Environmental influences on Child Health Outcomes (ECHO) Program. 
 3. AR140197 (MPI: Roberts

  1. Multipath interference test method for distributed amplifiers

    Science.gov (United States)

    Okada, Takahiro; Aida, Kazuo

    2005-12-01

    A method for testing distributed amplifiers is presented; the multipath interference (MPI) is detected as a beat spectrum between the multipath signal and the direct signal using a binary frequency shifted keying (FSK) test signal. The lightwave source is composed of a DFB-LD that is directly modulated by a pulse stream passing through an equalizer, and emits the FSK signal of the frequency deviation of about 430MHz at repetition rate of 80-100 kHz. The receiver consists of a photo-diode and an electrical spectrum analyzer (ESA). The base-band power spectrum peak appeared at the frequency of the FSK frequency deviation can be converted to amount of MPI using a calibration chart. The test method has improved the minimum detectable MPI as low as -70 dB, compared to that of -50 dB of the conventional test method. The detailed design and performance of the proposed method are discussed, including the MPI simulator for calibration procedure, computer simulations for evaluating the error caused by the FSK repetition rate and the fiber length under test and experiments on singlemode fibers and distributed Raman amplifier.

  2. Solving the Flood Propagation Problem with Newton Algorithm on Parallel Systems

    Directory of Open Access Journals (Sweden)

    Chefi Triki

    2012-04-01

    Full Text Available In this paper we propose a parallel implementation for the flood propagation method Flo2DH. The model is built on a finite element spatial approximation combined with a Newton algorithm that uses a direct LU linear solver. The parallel implementation has been developed by using the standard MPI protocol and has been tested on a set of real world problems.

  3. Prognosis of patients with positive exercise test and normal myocardial perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Seo, J. H.; Jeong, S. Y.; Bae, J. H.; Ahn, B. C.; Lee, J.; Lee, K. B [College of Medicine, Kyungpook National University, Daegu (Korea, Republic of)

    2004-07-01

    Exercise SPECT myocardial perfusion imaging(Ex-MPI) is regarded as a predictive technique particularly in patients with coronary artery disease(CAD) capable of performing exercise testing. In clinical practice, we encounter equivocal situations of discordant findings between exercise ECG and MPI. We evaluated the prognosis of subjects with positive ECG and normal MPI findings, and predictive factors for cardiac events. 2571 Ex-MPI studies were reviewed over a period of 3 years. Subjects were followed for more than 2 years(24-56 months, mean 35{+-}10months) for cardiac events after study. The cardiac events were defined as hard events(cardiac death and nonfatal myocardial infarction(MI)) and soft events(aggravation of CAD necessitating revascularization, congestive heart failure necessitating hospital admission). We evaluated age, sex, typical angina pain, rest ECG, hypertension, diabetes mellitus(DM), serum levels of cholesterol and LDL, smoking history, history of cerebrovascular disease(CVD) and peripheral artery disease(PAD), and rest left ventricular ejection fraction(LVEF) as clinical variables. Of 83 subjects with positive ECG and normal MPS findings, 6 were considered as false negative results confirmed with coronary angiography. There were 77 patients (mean age 52{+-}10 years, 39 males) with positive ECG and normal MPI results. During the follow-up period, of 77 there were 3 cardiac events (annual rate 1.9%), no cardiac death, 2 nonfatal MIs (annual rate 1.3%) and 1 soft event (annual rate 0.6%). 2/39 males(5.1%), and 1/38 females(2.6%) had cardiac events. All cardiac events were observed within 2 years. 1-year cardiac event rate was 0.6% and 2-year cardiac event rate was 1.9%. Among clinical factors, male sex, typical chest pain and smoking history at the time of MPI were predictive of cardiac events. Patients with positive ECG and negative EX-MPI results have low risk for cardiac events. Nevertheless, the cardiac events cannot be excluded totally in some

  4. Prognosis of patients with positive exercise test and normal myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    Seo, J. H.; Jeong, S. Y.; Bae, J. H.; Ahn, B. C.; Lee, J.; Lee, K. B

    2004-01-01

    Exercise SPECT myocardial perfusion imaging(Ex-MPI) is regarded as a predictive technique particularly in patients with coronary artery disease(CAD) capable of performing exercise testing. In clinical practice, we encounter equivocal situations of discordant findings between exercise ECG and MPI. We evaluated the prognosis of subjects with positive ECG and normal MPI findings, and predictive factors for cardiac events. 2571 Ex-MPI studies were reviewed over a period of 3 years. Subjects were followed for more than 2 years(24-56 months, mean 35±10months) for cardiac events after study. The cardiac events were defined as hard events(cardiac death and nonfatal myocardial infarction(MI)) and soft events(aggravation of CAD necessitating revascularization, congestive heart failure necessitating hospital admission). We evaluated age, sex, typical angina pain, rest ECG, hypertension, diabetes mellitus(DM), serum levels of cholesterol and LDL, smoking history, history of cerebrovascular disease(CVD) and peripheral artery disease(PAD), and rest left ventricular ejection fraction(LVEF) as clinical variables. Of 83 subjects with positive ECG and normal MPS findings, 6 were considered as false negative results confirmed with coronary angiography. There were 77 patients (mean age 52±10 years, 39 males) with positive ECG and normal MPI results. During the follow-up period, of 77 there were 3 cardiac events (annual rate 1.9%), no cardiac death, 2 nonfatal MIs (annual rate 1.3%) and 1 soft event (annual rate 0.6%). 2/39 males(5.1%), and 1/38 females(2.6%) had cardiac events. All cardiac events were observed within 2 years. 1-year cardiac event rate was 0.6% and 2-year cardiac event rate was 1.9%. Among clinical factors, male sex, typical chest pain and smoking history at the time of MPI were predictive of cardiac events. Patients with positive ECG and negative EX-MPI results have low risk for cardiac events. Nevertheless, the cardiac events cannot be excluded totally in some

  5. Nuclear cardiology in the UK: activity and practice 1997

    International Nuclear Information System (INIS)

    Prvulovich, Elizabeth; Metcalfe, Malcolm J.

    2002-01-01

    A questionnaire was sent to 251 nuclear medicine centres asking for details of nuclear medicine activity, and nuclear cardiology activity and practice in 1997. One hundred and seventy-one (68%) centres replied. Nuclear medicine activity was estimated at 11.8 studies/1,000 population/year, and 9.5% of these studies were within cardiology (1.12 studies/1,000/year). Myocardial perfusion imaging (MPI) studies accounted for 77% and radionuclide ventriculography (RNV) for 22% of all nuclear cardiology. On a national basis this represents activity levels of 0.86 and 0.25 studies/1,000/year for MPI and RNV, respectively. Of the 171 responding centres, 102 (60%) performed MPI studies and 81 (79%) of these reported that activity was increasing. However, MPI activity was unevenly distributed between hospitals. Two centres accounted for 13% of total MPI; others had far lower activity rates, and 51/102 (50%) centres performed less than 200 MPI studies/year. Comparison with previous surveys showed that nuclear medicine activity had almost doubled since 1990 (it was 6.0 studies/1,000 population in 1990, 9.3 studies/1,000 in 1994 and 11.8 studies/1,000 in 1997). Over the same period, nuclear cardiology activity had also risen, the greatest increase being seen for the last 3 years (it was 0.7 studies/1,000 population in 1990, 0.82 studies/1,000 in 1994 and 1.12 studies/1,000 in 1997). Despite these encouraging figures, MPI activity for 1997 remained well below that recommended by the British Cardiac Society in 1994 (2.6 studies/1,000/year) as adequate to serve the needs of patients with cardiac disease in the UK; it was also below the European average activity for the same year (2.2 studies/1,000/year). The anticipated increased workload for nuclear cardiology is encouraging despite the wide and varied practice of nuclear cardiology around the UK. The nuclear medicine community now needs to address the issues that will prevent it keeping up with demand, such as restricted camera

  6. Incremental Diagnostic Performance of Combined Parameters in the Detection of Severe Coronary Artery Disease Using Exercise Gated Myocardial Perfusion Imaging.

    Directory of Open Access Journals (Sweden)

    Chia-Ju Liu

    Full Text Available Myocardial perfusion imaging (MPI using gated single-photon emission tomography (gSPECT may underestimate the severity of coronary artery disease (CAD. This study aimed to evaluate the significance of combined parameters derived from gSPECT, as well as treadmill stress test parameters, in the detection of severe CAD.A total of 211 consecutive patients referred for exercise MPI between June 2011 and June 2013 (who received invasive coronary angiography within six months after MPI were retrospectively reviewed. Exercise MPI was performed with Bruce protocol and 201Tl injected at peak exercise. Gated SPECT was performed using a cadmium-zinc-telluride camera and processed by QPS/QGS software. Perfusion defect abnormalities such as sum stress score (SSS; sum difference score, algorithm-derived total perfusion deficits, transient ischemic dilatation ratios of end-diastolic volumes and end-systolic volumes, post-stress changes in ejection fraction, and lung/heart ratio (LHR were calculated. Treadmill parameters, including ST depression (STD at the 1st and 3rd minutes of recovery stage (1'STD and 3'STD, maximal STD corrected by heart rate increment (ST/HR, heart rate decline in 1st and 3rd minutes of recovery stage, recovery heart rate ratio (HR ratio, systolic and mean blood pressure ratios (SBP ratio and MAP ratio during recovery phase were recorded. Diagnostic performances of these parameters were analyzed with receiver operating characteristic (ROC analysis and logistic regression for detection of left main (≥ 50% or 3-vessel disease (all ≥ 70% luminal stenosis on invasive angiography.Among various MPI and treadmill parameters used for detection of severe CAD, SSS and ST/HR had the highest AUC (0.78, 0.73, p = NS and best cut-off values (SSS > 6, ST/HR > 17.39 10-2mV/bpm, respectively. By univariate logistic regression, all parameters except 1'HRR, 3'HRR, SBP and MAP ratios increased the odds ratio of severe CAD. Only increased L/H ratio, 3'STD

  7. Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera.

    Science.gov (United States)

    Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F; Erlandsson, Kjell; Sharir, Tali; Roth, Nathaniel; Waddington, Wendy A; Berman, Daniel S; Ell, Peter J

    2010-08-01

    We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5+/-11.8 years of age, 16 men) were injected with 74 MBq of (201)Tl (rest) and 250 MBq (99m)Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest (201)Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress (99m)Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest (201)Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest (201)Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, pstress perfusion defects were significantly larger on stress DR D-SPECT images, and five of these patients were imaged earlier by D-SPECT than by conventional SPECT. Fast and high-quality simultaneous DR MPI is feasible with D-SPECT in a

  8. Age-Related Difference in Functional Brain Connectivity of Mastication

    Science.gov (United States)

    Lin, Chia-shu; Wu, Ching-yi; Wu, Shih-yun; Lin, Hsiao-Han; Cheng, Dong-hui; Lo, Wen-liang

    2017-01-01

    The age-related decline in motor function is associated with changes in intrinsic brain signatures. Here, we investigated the functional connectivity (FC) associated with masticatory performance, a clinical index evaluating general masticatory function. Twenty-six older adults (OA) and 26 younger (YA) healthy adults were recruited and assessed using the masticatory performance index (MPI) and resting-state functional magnetic resonance imaging (rs-fMRI). We analyzed the rs-fMRI FC network related to mastication, which was constructed based on 12 bilateral mastication-related brain regions according to the literature. For the OA and the YA group, we identified the mastication-related hubs, i.e., the nodes for which the degree centrality (DC) was positively correlated with the MPI. For each pair of nodes, we identified the inter-nodal link for which the FC was positively correlated with the MPI. The network analysis revealed that, in the YA group, the FC between the sensorimotor cortex, the thalamus (THA) and the cerebellum was positively correlated with the MPI. Consistently, the cerebellum nodes were defined as the mastication-related hubs. In contrast, in the OA group, we found a sparser connection within the sensorimotor regions and cerebellum and a denser connection across distributed regions, including the FC between the superior parietal lobe (SPL), the anterior insula (aINS) and the dorsal anterior cingulate cortex (dACC). Compared to the YA group, the network of the OA group also comprised more mastication-related hubs, which were spatially distributed outside the sensorimotor regions, including the right SPL, the right aINS, and the bilateral dACC. In general, the findings supported the hypothesis that in OA, higher masticatory performance is associated with a widespread pattern of mastication-related hubs. Such a widespread engagement of multiple brain regions associated with the MPI may reflect an increased demand in sensorimotor integration, attentional

  9. Current worldwide nuclear cardiology practices and radiation exposure: results from the 65 country IAEA Nuclear Cardiology Protocols Cross-Sectional Study (INCAPS)

    Science.gov (United States)

    Einstein, Andrew J.; Pascual, Thomas N. B.; Mercuri, Mathew; Karthikeyan, Ganesan; Vitola, João V.; Mahmarian, John J.; Better, Nathan; Bouyoucef, Salah E.; Hee-Seung Bom, Henry; Lele, Vikram; Magboo, V. Peter C.; Alexánderson, Erick; Allam, Adel H.; Al-Mallah, Mouaz H.; Flotats, Albert; Jerome, Scott; Kaufmann, Philipp A.; Luxenburg, Osnat; Shaw, Leslee J.; Underwood, S. Richard; Rehani, Madan M.; Kashyap, Ravi; Paez, Diana; Dondi, Maurizio

    2015-01-01

    Aims To characterize patient radiation doses from nuclear myocardial perfusion imaging (MPI) and the use of radiation-optimizing ‘best practices’ worldwide, and to evaluate the relationship between laboratory use of best practices and patient radiation dose. Methods and results We conducted an observational cross-sectional study of protocols used for all 7911 MPI studies performed in 308 nuclear cardiology laboratories in 65 countries for a single week in March–April 2013. Eight ‘best practices’ relating to radiation exposure were identified a priori by an expert committee, and a radiation-related quality index (QI) devised indicating the number of best practices used by a laboratory. Patient radiation effective dose (ED) ranged between 0.8 and 35.6 mSv (median 10.0 mSv). Average laboratory ED ranged from 2.2 to 24.4 mSv (median 10.4 mSv); only 91 (30%) laboratories achieved the median ED ≤ 9 mSv recommended by guidelines. Laboratory QIs ranged from 2 to 8 (median 5). Both ED and QI differed significantly between laboratories, countries, and world regions. The lowest median ED (8.0 mSv), in Europe, coincided with high best-practice adherence (mean laboratory QI 6.2). The highest doses (median 12.1 mSv) and low QI (4.9) occurred in Latin America. In hierarchical regression modelling, patients undergoing MPI at laboratories following more ‘best practices’ had lower EDs. Conclusion Marked worldwide variation exists in radiation safety practices pertaining to MPI, with targeted EDs currently achieved in a minority of laboratories. The significant relationship between best-practice implementation and lower doses indicates numerous opportunities to reduce radiation exposure from MPI globally. PMID:25898845

  10. Multilevel Parallelization of AutoDock 4.2

    Directory of Open Access Journals (Sweden)

    Norgan Andrew P

    2011-04-01

    Full Text Available Abstract Background Virtual (computational screening is an increasingly important tool for drug discovery. AutoDock is a popular open-source application for performing molecular docking, the prediction of ligand-receptor interactions. AutoDock is a serial application, though several previous efforts have parallelized various aspects of the program. In this paper, we report on a multi-level parallelization of AutoDock 4.2 (mpAD4. Results Using MPI and OpenMP, AutoDock 4.2 was parallelized for use on MPI-enabled systems and to multithread the execution of individual docking jobs. In addition, code was implemented to reduce input/output (I/O traffic by reusing grid maps at each node from docking to docking. Performance of mpAD4 was examined on two multiprocessor computers. Conclusions Using MPI with OpenMP multithreading, mpAD4 scales with near linearity on the multiprocessor systems tested. In situations where I/O is limiting, reuse of grid maps reduces both system I/O and overall screening time. Multithreading of AutoDock's Lamarkian Genetic Algorithm with OpenMP increases the speed of execution of individual docking jobs, and when combined with MPI parallelization can significantly reduce the execution time of virtual screens. This work is significant in that mpAD4 speeds the execution of certain molecular docking workloads and allows the user to optimize the degree of system-level (MPI and node-level (OpenMP parallelization to best fit both workloads and computational resources.

  11. Multilevel Parallelization of AutoDock 4.2.

    Science.gov (United States)

    Norgan, Andrew P; Coffman, Paul K; Kocher, Jean-Pierre A; Katzmann, David J; Sosa, Carlos P

    2011-04-28

    Virtual (computational) screening is an increasingly important tool for drug discovery. AutoDock is a popular open-source application for performing molecular docking, the prediction of ligand-receptor interactions. AutoDock is a serial application, though several previous efforts have parallelized various aspects of the program. In this paper, we report on a multi-level parallelization of AutoDock 4.2 (mpAD4). Using MPI and OpenMP, AutoDock 4.2 was parallelized for use on MPI-enabled systems and to multithread the execution of individual docking jobs. In addition, code was implemented to reduce input/output (I/O) traffic by reusing grid maps at each node from docking to docking. Performance of mpAD4 was examined on two multiprocessor computers. Using MPI with OpenMP multithreading, mpAD4 scales with near linearity on the multiprocessor systems tested. In situations where I/O is limiting, reuse of grid maps reduces both system I/O and overall screening time. Multithreading of AutoDock's Lamarkian Genetic Algorithm with OpenMP increases the speed of execution of individual docking jobs, and when combined with MPI parallelization can significantly reduce the execution time of virtual screens. This work is significant in that mpAD4 speeds the execution of certain molecular docking workloads and allows the user to optimize the degree of system-level (MPI) and node-level (OpenMP) parallelization to best fit both workloads and computational resources.

  12. SurF: an innovative framework in biosecurity and animal health surveillance evaluation.

    Science.gov (United States)

    Muellner, Petra; Watts, Jonathan; Bingham, Paul; Bullians, Mark; Gould, Brendan; Pande, Anjali; Riding, Tim; Stevens, Paul; Vink, Daan; Stärk, Katharina Dc

    2018-05-16

    Surveillance for biosecurity hazards is being conducted by the New Zealand Competent Authority, the Ministry for Primary Industries (MPI) to support New Zealand's biosecurity system. Surveillance evaluation should be an integral part of the surveillance life cycle, as it provides a means to identify and correct problems and to sustain and enhance the existing strengths of a surveillance system. The surveillance evaluation Framework (SurF) presented here was developed to provide a generic framework within which the MPI biosecurity surveillance portfolio, and all of its components, can be consistently assessed. SurF is an innovative, cross-sectoral effort that aims to provide a common umbrella for surveillance evaluation in the animal, plant, environment and aquatic sectors. It supports the conduct of the following four distinct components of an evaluation project: (i) motivation for the evaluation, (ii) scope of the evaluation, (iii) evaluation design and implementation and (iv) reporting and communication of evaluation outputs. Case studies, prepared by MPI subject matter experts, are included in the framework to guide users in their assessment. Three case studies were used in the development of SurF in order to assure practical utility and to confirm usability of SurF across all included sectors. It is anticipated that the structured approach and information provided by SurF will not only be of benefit to MPI but also to other New Zealand stakeholders. Although SurF was developed for internal use by MPI, it could be applied to any surveillance system in New Zealand or elsewhere. © 2018 2018 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

  13. Improvement of the myocardial performance index in atrial fibrilation patients treated with amiodarone after cardioversion.

    Science.gov (United States)

    Besli, Feyzullah; Basar, Cengiz; Kecebas, Mesut; Turker, Yasin

    2015-03-01

    This study evaluated the response to electrical cardioversion (EC) and the effect on the myocardial performance index (MPI) in patients with persistent and long-standing persistent atrial fibrillation (AF). We enrolled 103 patients (mean age 69.6 ± 8.9 years, 40.7% males) with a diagnosis of persistent and long-standing persistent AF. EC was applied to all patients after one g of amiodarone administration. Echocardiographic findings before EC were compared in patients with successful versus unsuccessful cardioversions and in patients with maintained sinus rhythm (SR) versus those with AF recurrence at the end of the first month. We also compared echocardiographic data before EC versus at the end of the first month in the same patients with maintained SR. SR was achieved in 72.8% of patients and was continued at the end of the first month in 69.3% of the patients. The MPI value of all patients was found to be 0.73 ± 0.21. The size of the left atrium was determined to be an independent predictor of the maintenance of SR at 1 month. In subgroup analyses, when we compared echocardiographic findings before EC and at the end of the first month in patients with maintained SR, the MPI (0.66 ± 0.14 vs 0.56 ± 0.09, p < 0.001) values were significantly decreased. Our study is the first to show impairment of the MPI, which is an indicator of systolic and diastolic function, in patients with persistent and long-standing persistent AF and improvement of the MPI after successful EC.

  14. Technologies and tools for high-performance distributed computing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Karonis, Nicholas T.

    2000-05-01

    In this project we studied the practical use of the MPI message-passing interface in advanced distributed computing environments. We built on the existing software infrastructure provided by the Globus Toolkit{trademark}, the MPICH portable implementation of MPI, and the MPICH-G integration of MPICH with Globus. As a result of this project we have replaced MPICH-G with its successor MPICH-G2, which is also an integration of MPICH with Globus. MPICH-G2 delivers significant improvements in message passing performance when compared to its predecessor MPICH-G and was based on superior software design principles resulting in a software base that was much easier to make the functional extensions and improvements we did. Using Globus services we replaced the default implementation of MPI's collective operations in MPICH-G2 with more efficient multilevel topology-aware collective operations which, in turn, led to the development of a new timing methodology for broadcasts [8]. MPICH-G2 was extended to include client/server functionality from the MPI-2 standard [23] to facilitate remote visualization applications and, through the use of MPI idioms, MPICH-G2 provided application-level control of quality-of-service parameters as well as application-level discovery of underlying Grid-topology information. Finally, MPICH-G2 was successfully used in a number of applications including an award-winning record-setting computation in numerical relativity. In the sections that follow we describe in detail the accomplishments of this project, we present experimental results quantifying the performance improvements, and conclude with a discussion of our applications experiences. This project resulted in a significant increase in the utility of MPICH-G2.

  15. Assessment of prognostic value of semiquantitative parameters on gated single photon emission computed tomography myocardial perfusion scintigraphy in a large middle eastern population

    International Nuclear Information System (INIS)

    Chavoshi, Maryam; Fard-Esfahani, Armaghan; Fallahi, Babak; Emami-Ardekani, Alireza; Beiki, Davood; Hassanzadeh-Rad, Arman; Eftekhari, Mohammad

    2005-01-01

    Coronary artery disease is the leading cause of mortality worldwide. The goal of this study is to determine the prognostic value of semiquantitative parameters of electrocardiogram-gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a large Middle Eastern (Iranian) population. This study was a prospective study including all patients referred to our center for myocardial perfusion scan. The patients were followed annually up to 24 months and their survival information was collected. From 1148 patients, 473 (41.2%) men and 675 (58.8%) women, 40.6% had normal MPI, 13.3% near normal and 46.1% abnormal MPI. After follow-up of 929 patients, 97.4% of patients were alive, and 2.6% succumbed to cardiac deaths. Abnormal ejection fraction was related with cardiac events (P = 0.001), but neither transient ischemic dilation (TID) (P = 0.09) nor lung/heart ratio (P = 0.92) showed such relationship. Association between summed difference score (SDS) and soft cardiac events (P < 0.001) was significant. Summed motion score (SMS) and summed thickening score (STS) showed a significant relation with hard cardiac events, including myocardial infarction and cardiac death (P < 0.001 and P = 0.001, respectively). Totally, risk of all cardiac events was significantly higher in abnormal MPI group than normal group (P < 0.001, 0.02, and 0.025, respectively). No significant relationship was found between TID and total cardiac events (P = 0.478). Semiquantitative variables derived from gated SPECT MPI have independent prognostic value. Rate of total cardiac events is higher in patients with higher summed stress score and SDS. Total and hard cardiac events are higher in upper scores of functional parameters (SMS and STS). Total cardiac events are higher in patients with lower left ventricular ejection fraction

  16. Mobile evaporator corrosion test results

    International Nuclear Information System (INIS)

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80 degrees C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either open-quotes satisfactoryclose quotes (2-20 mpy) or open-quotes excellentclose quotes (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment

  17. Future cardiac events in patients with ischemic ECG changes during adenosine infusion as a myocardial stress agent and normal cardiac scan.

    Science.gov (United States)

    Amer, Hamid; Niaz, Khalid; Hatazawa, Jun; Gasmelseed, Ahmed; Samiri, Hussain Al; Al Othman, Maram; Hammad, Mai Al

    2017-11-01

    We sought to determine the prognostic importance of adenosine-induced ischemic ECG changes in patients with normal single-photon emission computed tomography myocardial perfusion images (MPI). We carried out a retrospective analysis of 765 patients undergoing adenosine MPI between January 2013 and January 2015. Patients with baseline ECG abnormalities and/or abnormal scan were excluded. Overall, 67 (8.7%) patients had ischemic ECG changes during adenosine infusion in the form of ST depression of 1 mm or more. Of these, 29 [43% (3.8% of all patients)] had normal MPI (positive ECG group). An age-matched and sex-matched group of 108 patients with normal MPI without ECG changes served as control participants (negative ECG group). During a mean follow-up duration of 33.3±6.1 months, patients in the positive ECG group did not have significantly more adverse cardiac events than those in the negative ECG group. One (0.9%) patient in the negative ECG group had a nonfatal myocardial infarction (0.7% annual event rate after a negative MPI). Also in this group, two (1.8%) patients admitted with a diagnosis of CAD where they have been ruled out by angiography. A fourth case in this, in the negative ECG group, was admitted because of heart failure that proved to be secondary to a pulmonary cause and not CAD. A case only in the positive ECG group was admitted as a CAD that was ruled out by coronary angiography. Patients with normal myocardial perfusion scintigraphy in whom ST-segment depression develops during adenosine stress test appear to have no increased risk for future cardiac events compared with similar patients without ECG evidence of ischemia.

  18. Deep Learning for Prediction of Obstructive Disease From Fast Myocardial Perfusion SPECT: A Multicenter Study.

    Science.gov (United States)

    Betancur, Julian; Commandeur, Frederic; Motlagh, Mahsaw; Sharir, Tali; Einstein, Andrew J; Bokhari, Sabahat; Fish, Mathews B; Ruddy, Terrence D; Kaufmann, Philipp; Sinusas, Albert J; Miller, Edward J; Bateman, Timothy M; Dorbala, Sharmila; Di Carli, Marcelo; Germano, Guido; Otaki, Yuka; Tamarappoo, Balaji K; Dey, Damini; Berman, Daniel S; Slomka, Piotr J

    2018-03-12

    The study evaluated the automatic prediction of obstructive disease from myocardial perfusion imaging (MPI) by deep learning as compared with total perfusion deficit (TPD). Deep convolutional neural networks trained with a large multicenter population may provide improved prediction of per-patient and per-vessel coronary artery disease from single-photon emission computed tomography MPI. A total of 1,638 patients (67% men) without known coronary artery disease, undergoing stress 99m Tc-sestamibi or tetrofosmin MPI with new generation solid-state scanners in 9 different sites, with invasive coronary angiography performed within 6 months of MPI, were studied. Obstructive disease was defined as ≥70% narrowing of coronary arteries (≥50% for left main artery). Left ventricular myocardium was segmented using clinical nuclear cardiology software and verified by an expert reader. Stress TPD was computed using sex- and camera-specific normal limits. Deep learning was trained using raw and quantitative polar maps and evaluated for prediction of obstructive stenosis in a stratified 10-fold cross-validation procedure. A total of 1,018 (62%) patients and 1,797 of 4,914 (37%) arteries had obstructive disease. Area under the receiver-operating characteristic curve for disease prediction by deep learning was higher than for TPD (per patient: 0.80 vs. 0.78; per vessel: 0.76 vs. 0.73: p deep learning threshold set to the same specificity as TPD, per-patient sensitivity improved from 79.8% (TPD) to 82.3% (deep learning) (p deep learning) (p Deep learning has the potential to improve automatic interpretation of MPI as compared with current clinical methods. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  19. Undernutrition, fatty acid and micronutrient status in relation to cognitive performance in Indian school children: a cross-sectional study.

    Science.gov (United States)

    Eilander, Ans; Muthayya, Sumithra; van der Knaap, Henk; Srinivasan, Krishnamachari; Thomas, Tinku; Kok, Frans J; Kurpad, Anura V; Osendarp, Saskia J M

    2010-04-01

    While undernutrition and anaemia have previously been linked to poor development of children, relatively little is known about the role of B-vitamins and fatty acids on cognition. The present study aims to explore the associations between indicators of body size, fatty acid and micronutrient status on cognitive performance in 598 Indian school children aged 6-10 years. Baseline data of a clinical study were used to assess these associations by analyses of variance adjusting for age, sex, school, maternal education and cognitive tester. The Kaufman Assessment Battery for Children II was used to measure four cognitive domains, including fluid reasoning, short-term memory, retrieval ability and cognitive speediness. Scores were combined into an overall measure, named mental processing index (MPI). Body size indicators and Hb concentrations were significantly positively related to cognitive domains and MPI, such that increases of 1 sd in height-for-age and weight-for-age z-scores would each translate into a 0.09 sd increase in MPI, P = 0.0006 and 0.002, respectively. A 10 g/l increase in Hb concentrations would translate into a 0.08 sd increase in MPI, P = 0.0008. Log-transformed vitamin B12 concentrations were significantly inversely associated with short-term memory, retrieval ability and MPI (beta (95 % CI) = - 0.124 (- 0.224, - 0.023), P = 0.02). Other indicators of Fe, iodine, folate and fatty acid status were not significantly related to cognition. Our findings for body size, fatty acids and micronutrients were in agreement with previous observational studies. The inverse association of vitamin B12 with mental development was unexpected and needed further study.

  20. Response properties of the refractory auditory nerve fiber.

    Science.gov (United States)

    Miller, C A; Abbas, P J; Robinson, B K

    2001-09-01

    The refractory characteristics of auditory nerve fibers limit their ability to accurately encode temporal information. Therefore, they are relevant to the design of cochlear prostheses. It is also possible that the refractory property could be exploited by prosthetic devices to improve information transfer, as refractoriness may enhance the nerve's stochastic properties. Furthermore, refractory data are needed for the development of accurate computational models of auditory nerve fibers. We applied a two-pulse forward-masking paradigm to a feline model of the human auditory nerve to assess refractory properties of single fibers. Each fiber was driven to refractoriness by a single (masker) current pulse delivered intracochlearly. Properties of firing efficiency, latency, jitter, spike amplitude, and relative spread (a measure of dynamic range and stochasticity) were examined by exciting fibers with a second (probe) pulse and systematically varying the masker-probe interval (MPI). Responses to monophasic cathodic current pulses were analyzed. We estimated the mean absolute refractory period to be about 330 micros and the mean recovery time constant to be about 410 micros. A significant proportion of fibers (13 of 34) responded to the probe pulse with MPIs as short as 500 micros. Spike amplitude decreased with decreasing MPI, a finding relevant to the development of computational nerve-fiber models, interpretation of gross evoked potentials, and models of more central neural processing. A small mean decrement in spike jitter was noted at small MPI values. Some trends (such as spike latency-vs-MPI) varied across fibers, suggesting that sites of excitation varied across fibers. Relative spread was found to increase with decreasing MPI values, providing direct evidence that stochastic properties of fibers are altered under conditions of refractoriness.

  1. Psychometric Properties of the Multidimensional Pain Inventory Applied to Brazilian Patients with Orofacial Pain.

    Science.gov (United States)

    Zucoloto, Miriane Lucindo; Maroco, João; Duarte Bonini Campos, Juliana Alvares

    2015-01-01

    To evaluate the psychometric properties of the Multidimensional Pain Inventory (MPI) in a Brazilian sample of patients with orofacial pain. A total of 1,925 adult patients, who sought dental care in the School of Dentistry of São Paulo State University's Araraquara campus, were invited to participate; 62.5% (n=1,203) agreed to participate. Of these, 436 presented with orofacial pain and were included. The mean age was 39.9 (SD=13.6) years and 74.5% were female. Confirmatory factor analysis was conducted using χ²/df, comparative fit index, goodness of fit index, and root mean square error of approximation as indices of goodness of fit. Convergent validity was estimated by the average variance extracted and composite reliability, and internal consistency by Cronbach's alpha standardized coefficient (α). The stability of the models was tested in independent samples (test and validation; dental pain and orofacial pain). The factorial invariance was estimated by multigroup analysis (Δχ²). Factorial, convergent validity, and internal consistency were adequate in all three parts of the MPI. To achieve this adequate fit for Part 1, item 15 needed to be deleted (λ=0.13). Discriminant validity was compromised between the factors "activities outside the home" and "social activities" of Part 3 of the MPI in the total sample, validation sample, and in patients with dental pain and with orofacial pain. A strong invariance between different subsamples from the three parts of the MPI was detected. The MPI produced valid, reliable, and stable data for pain assessment among Brazilian patients with orofacial pain.

  2. Assessment of left ventricular function by gated myocardial perfusion and gated blood-pool SPECT. Can we use the same reference database?

    Energy Technology Data Exchange (ETDEWEB)

    Paul, A.K.; Hasegawa, Shinji; Yoshioka, Jun; Yamaguchi, Hitoshi; Tsujimura, Eiichiro; Nishimura, Tsunehiko [Osaka Univ., Suita (Japan). Graduate School of Medicine

    2000-04-01

    The purpose of this study was to compare left ventricular (LV) volume and ejection fraction (LVEF) measurements obtained with electrocardiographic gated single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (GS-MPI) with those obtained with gated SPECT cardiac blood-pool imaging (GS-pool). Fifteen patients underwent GS-MPI with technetium-99m tetrofosmin and GS-pool with technetium-99m-erythrocyte, within a mean interval of 8{+-}3 days. Eight patients had suspected dilated cardiomyopathy and seven patients had angiographically significant coronary artery disease. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF measurements were estimated from GS-MPI images by means of Cedars-Sinai automatic quantitative program and from GS-pool images by the threshold technique. Mean differences between GS-MPI and GS-pool in EDV, ESV and LVEF measurements were -2.8{+-}10.5 ml [95% confidence interval (CI): -8.6{+-}3.0 ml], 2.6{+-}7.3 ml (CI: -1.4-6.6 ml) and -2.3{+-}5.1% (CI: -5.1-0.6%), respectively. No significant difference in the mean differences from 0 was found for EDV, ESV or LVEF measurements. Bland-Altman plots revealed no trend over the measured LV volumes and LVEF. For all parameters, regression lines approximated lines of identity. The excellent agreement between GS-MPI and GS-pool measurements suggests that, for estimation of LV volumes and LVEF, these two techniques may be used interchangeably and measurements by one method can serve as a reference for the other. (author)

  3. Hot-wall corrosion testing of simulated high level nuclear waste

    International Nuclear Information System (INIS)

    Chandler, G.T.; Zapp, P.E.; Mickalonis, J.I.

    1995-01-01

    Three materials of construction for steam tubes used in the evaporation of high level radioactive waste were tested under heat flux conditions, referred to as hot-wall tests. The materials were type 304L stainless steel alloy C276, and alloy G3. Non-radioactive acidic and alkaline salt solutions containing halides and mercury simulated different high level waste solutions stored or processed at the United States Department of Energy's Savannah River Site. Alloy C276 was also tested for corrosion susceptibility under steady-state conditions. The nickel-based alloys C276 and G3 exhibited excellent corrosion resistance under the conditions studied. Alloy C276 was not susceptible to localized corrosion and had a corrosion rate of 0.01 mpy (0.25 μm/y) when exposed to acidic waste sludge and precipitate slurry at a hot-wall temperature of 150 degrees C. Type 304L was susceptible to localized corrosion under the same conditions. Alloy G3 had a corrosion rate of 0.1 mpy (2.5 μm/y) when exposed to caustic high level waste evaporator solution at a hot-wall temperature of 220 degrees C compared to 1.1 mpy (28.0 μ/y) for type 304L. Under extreme caustic conditions (45 weight percent sodium hydroxide) G3 had a corrosion rate of 0.1 mpy (2.5 μm/y) at a hot-wall temperature of 180 degrees C while type 304L had a high corrosion rate of 69.4 mpy (1.8 mm/y)

  4. Experimental and simulation studies on the behavior of signal harmonics in magnetic particle imaging.

    Science.gov (United States)

    Murase, Kenya; Konishi, Takashi; Takeuchi, Yuki; Takata, Hiroshige; Saito, Shigeyoshi

    2013-07-01

    Our purpose in this study was to investigate the behavior of signal harmonics in magnetic particle imaging (MPI) by experimental and simulation studies. In the experimental studies, we made an apparatus for MPI in which both a drive magnetic field (DMF) and a selection magnetic field (SMF) were generated with a Maxwell coil pair. The MPI signals from magnetic nanoparticles (MNPs) were detected with a solenoid coil. The odd- and even-numbered harmonics were calculated by Fourier transformation with or without background subtraction. The particle size of the MNPs was measured by transmission electron microscopy (TEM), dynamic light-scattering, and X-ray diffraction methods. In the simulation studies, the magnetization and particle size distribution of MNPs were assumed to obey the Langevin theory of paramagnetism and a log-normal distribution, respectively. The odd- and even-numbered harmonics were calculated by Fourier transformation under various conditions of DMF and SMF and for three different particle sizes. The behavior of the harmonics largely depended on the size of the MNPs. When we used the particle size obtained from the TEM image, the simulation results were most similar to the experimental results. The similarity between the experimental and simulation results for the even-numbered harmonics was better than that for the odd-numbered harmonics. This was considered to be due to the fact that the odd-numbered harmonics were more sensitive to background subtraction than were the even-numbered harmonics. This study will be useful for a better understanding, optimization, and development of MPI and for designing MNPs appropriate for MPI.

  5. Impact of insurance carrier, prior authorization, and socioeconomic status on appropriate use of SPECT myocardial perfusion imaging in private community-based office practice.

    Science.gov (United States)

    Doukky, Rami; Hayes, Kathleen; Frogge, Nathan; Nazir, Noreen T; Collado, Fareed M; Williams, Kim A

    2015-05-01

    The impact of health insurance carrier and socioeconomic status (SES) on the adherence to appropriate use criteria (AUC) for radionuclide myocardial perfusion imaging (MPI) is unknown. Health insurance carrier's prior authorization and patient's SES impact adherence to AUC for MPI in a fee-for-service setting. We conducted a prospective cohort study of 1511 consecutive patients who underwent outpatient MPI in a multi-site, office-based, fee-for-service setting. The patients were stratified according to the 2009 AUC into appropriate/uncertain appropriateness and inappropriate use groups. Insurance status was categorized as Medicare (does not require prior authorization) vs commercial (requires prior authorization). Socioeconomic status was determined by the median household income in the ZIP code of residence. The proportion of patients with Medicare was 33% vs 67% with commercial insurance. The rate of inappropriate use was higher among patients with commercial insurance vs Medicare (55% vs 24%; P impact AUC determination (odds ratio: 1.06, 95% confidence interval: 0.62-1.82, P = 0.82). The mean annual household income in the residential areas of patients with inappropriate use as compared to those with appropriate/uncertain use was $72 000 ± 21 000 vs $68 000 ± 20 000, respectively (P impact AUC determination, SES (top vs bottom quartile income area) was not independently predictive of inappropriate MPI use (odds ratio: 0.9, 95% confidence interval: 0.53-1.52, P = 0.69). Insurance carriers prior authorization and SES do not seem to play a significant role in determining physicians adherence to AUC for MPI. © 2015 Wiley Periodicals, Inc.

  6. Comparative study of gated myocardial perfusion imaging using 99Tcm-tetrofosmin and 99Tcm-sestamibi

    International Nuclear Information System (INIS)

    Wang Ruihua; Ruan Qiao; Sun Ke; Han Xingmin; Sun Bingqi; Xie Xinli; Cheng Bing; Chen Yanlin; Liu Baoping

    2013-01-01

    Objective: To compare the results of 99 Tc m -tetrofosmin (TF) and 99 Tc m -MIBI G-MPI in evaluating left ventricular myocardial perfusion and other functional parameters. Methods: TF and MIBI were both labeled by 99 Tc m and the radiochemical purities were tested. During December 2011 to May 2012, 112 patients who had examinations of CAG and echocardiograph in one week after G-MPI were divided into 99 Tc m -TF group (47 patients) and 99 Tc m -MIBI group (65 patients) by simple random sampling. Patients who suffered from severe arrhythmia, clinically suspicious of myocarditis or cardiomyopathy were excluded. The research was approved by the ethics committee, and all patients signed informed consents. One-day 99 Tc m -TF G-MPI and two-day 99 Tc m -MIBI G-MPI were performed. The left ventricular functional parameters were acquired automatically by Cedars quantitative gated SPECT (QGS) software, including LVEF, EDV, ESV, peak filling rate (PFR), peak ejection rate (PER) and phase standard difference (SD). The data were analyzed using χ 2 test, two-sample t test, paired t test and linear correlation analysis by SPSS 17.0. Results: The radiochemical purities of 99 Tc m -TF and 99 Tc m -MIBI were (97.5±0.4) % and (99.1±0.2) % respectively. The coincidence rates of 99 Tc m -TF and 99 Tc m -MIBI G-MPI with CAG were 88.9% (40/45) and 90.5% (57/63), respectively. There was no significant difference between G-MPI results of the two agents (χ 2 =0.389, P>0.05). There was also no significant difference between left ventricular functional parameters of the two agents (LVEF:(62.60±13.56)% vs (60.52±7.08)%, t=0.940; EDV: (103.3±17.29) ml vs (98.52±19.37) ml, t=1.348; ESV: (41.73±12.69) ml vs (46.05±10.81) ml, t=0.851; PER: (2.73±0.67)EDV/s vs (2.61±1.04) EDV/s, t=0.725; PFR: (2.13±0.80) EDV/s vs (2.07±1.09) EDV/s, t=0.339; phase SD: (5.58±4.16)° vs (5.97±4.64)°, t=0.450; all P>0.05). There was no significant difference between left ventricular functional

  7. Analysis of prognostic value of clinical information and myocardial perfusion imaging in diabetic patients on cardiac events occurrence

    International Nuclear Information System (INIS)

    Wu Zhifang; Li Sijin

    2004-01-01

    Objective: To explore the risk factors of cardiac event (CE) occurrence and evaluate the prognostic value of myocardial perfusion imaging (MPI) in diabetic patients. Methods: We conducted a study with 172(16.4%) consecutively registered patients with diabetes (132 males, 40 females; age range 16-90 years, mean age 55.94±12.46 years) and 875(83.6%) patients without diabetes with known or suspected coronary artery disease (CAD) undergoing SPECT MPI. Follow-up information was obtained through telephone interviews. Patients were followed up for at least 18 months. End points were defined as death due to primary cardiac cause, or nonfatal acute myocardial infarction and revascularization. The mean time of follow-up was 33.25±14.95 (1∼56) months. Results: Logistic stepwise regression analysis evaluated history of smoking and drinking, hypertension, hyperlipemia and the family history of CAD as predictors. A multiple regression formula was obtained: Y=-5.593+0.958X1+0.921 X2+0.428X3, (Y=cardiac events, X1=diabetes, X2=the family history of CAD, X3=hypertension). Diabetes, the family history of CAD and hypertension were dangerous factors for cardiac events, but hyperlipemia, history of smoking and drinking were protective factors for cardiac events. Over the follow-up period, there are 42 cardiac events in diabetic group, 86 in non-diabetic group. Patients with diabetes had significantly higher rates of cardiac events (24.4% versus 9.8%; chi-square 28.5, P<0.0001), compared with rates among patients without diabetes (table 1). Kaplan-Meier survival curves analyzing the no-CE rates in the diabetic and non-diabetic groups, diabetic patients were significantly lower than non-diabetic ones (Log-rank statistic, chi-square 28.75, P <0.0001). Of 172 diabetic patients, 32.2% of the patients with abnormal MPI occurred cardiac events, but only 7.4% of the patients with normal ones did(chi-square 12.34, P <0.001) (figure 1). Abnormal SPECT MPI was associated with the higher rate

  8. High-Performance Data Analysis Tools for Sun-Earth Connection Missions

    Science.gov (United States)

    Messmer, Peter

    2011-01-01

    The data analysis tool of choice for many Sun-Earth Connection missions is the Interactive Data Language (IDL) by ITT VIS. The increasing amount of data produced by these missions and the increasing complexity of image processing algorithms requires access to higher computing power. Parallel computing is a cost-effective way to increase the speed of computation, but algorithms oftentimes have to be modified to take advantage of parallel systems. Enhancing IDL to work on clusters gives scientists access to increased performance in a familiar programming environment. The goal of this project was to enable IDL applications to benefit from both computing clusters as well as graphics processing units (GPUs) for accelerating data analysis tasks. The tool suite developed in this project enables scientists now to solve demanding data analysis problems in IDL that previously required specialized software, and it allows them to be solved orders of magnitude faster than on conventional PCs. The tool suite consists of three components: (1) TaskDL, a software tool that simplifies the creation and management of task farms, collections of tasks that can be processed independently and require only small amounts of data communication; (2) mpiDL, a tool that allows IDL developers to use the Message Passing Interface (MPI) inside IDL for problems that require large amounts of data to be exchanged among multiple processors; and (3) GPULib, a tool that simplifies the use of GPUs as mathematical coprocessors from within IDL. mpiDL is unique in its support for the full MPI standard and its support of a broad range of MPI implementations. GPULib is unique in enabling users to take advantage of an inexpensive piece of hardware, possibly already installed in their computer, and achieve orders of magnitude faster execution time for numerically complex algorithms. TaskDL enables the simple setup and management of task farms on compute clusters. The products developed in this project have the

  9. Echocardiographic evaluation of patients with subacute sclerosing panencephalitis

    Directory of Open Access Journals (Sweden)

    Derya Çimen

    2014-03-01

    Full Text Available Objective: Subacute sclerosing panencephalitis is a slowly progressive, inflammatory and neurodegenerative disease caused by virus infection in the central nervous system. Since there are a limited number of studies in the literature evaluating the cardiovascular functions of patients with SSPE, the present study evaluates the patients with SSPE using tissue Doppler echocardiography and compares them between the control group in order to shed some light on the subject. Methods: The study is a prospective observational study. 49 patients (17 female, 32 male with SSPE were included in the study. Patients were divided into two groups: Stage 2 (n=29 and Stage 3 (n=20. Echocardiographic data were compared with a control group of 26 which is the same average age. All children underwent a detailed echocardiography, which contained an M-mode, pulse Doppler and tissue Doppler imaging. Results: Sinus tachycardia ( >100 beats/min in children was detected in nineteen (38.7% patients. There were not significant differences between parameters of systolic and diastolic function of the heart. Stage 2 group, EF: 69.9±6.4; SF: 39.2±5.58; and MPI (mitral: 0.38±0.03 and MPI (tricuspid: 0.39±0.10. And in the Stage 3 group, EF: 68.5±7.0, SF: 37.8±5.34, MPI (mitral: 0.37±0.09 and MPI (tricuspid: 0.38±0.12. In the control group EF:70.96±5.54; SF:39.96±5.05 and MPI(mitral: 0.35±0.06 MPI (tricuspid:0.36±0.04 and statistically meaningful differences were not found between patients and control groups (p >0.05. Conclusion: Cardiac functions may be preserved and cardiac functions constitute no significant risks of mortality in the advanced stages of patients with Subacute sclerosing panencephalitis, which is a group of chronic and bedridden patients.

  10. Diagnostic value of stress-rest myocardial perfusion imaging in detection of coronary disease in elderly patients

    International Nuclear Information System (INIS)

    Han Pingping; Tian Yueqin; Fang Wei; Shen Rui; Yang Minfu; Wei Hongxing; Guo Xinhua; He Zuoxiang

    2009-01-01

    Objective: Coronary artery disease is one of the most common causes of death in elderly people. Yet, definite diagnosis is a dilemma due to the variety of symptoms and signs. The aim of this study was to evaluate the diagnostic value of nuclear stress-rest myocardial perfusion imaging(MPI) in detection of coronary disease in the elderly. Methods: Two hundred and five elderly subjects (≥60 years old, average of 67 ± 5) who were suspected to have coronary disease, underwent both stress-rest myocardial perfusion imaging (185 with exercise stress and 20 with adenosine stress) and coronary angiography (CAG). All had no pereutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Coronary angiography was used as a 'golden standard' to evaluate the sensitivity, specificity and accuracy of the stress-rest myocardial perfusion imaging. χ 2 -test was used in data analysis with SPSS 15.0. Results: Among 205 patients. there were 57 patients with an abnormal CAG result and 148 patients with a normal result. Of the 57 patients, there were 30 one-, 19 two-, and 8 three-vessel stenosis. Fifteen were mild-, 17 were moderate-, 17 were severe stenosis, and 8 were totally occluded.About 63% (36/57) had positive stress-rest MPI. Of the 148 subjects who had a normal CAG, 135 had negative MPL. The sensitivity.specificity and accuracy of stress MPI were 63% (36/57), 91% (135/148) and 83% (171/205) in patient level.respectively. The di-agnostic sensitivities of stress-rest MPI for detection of one-, two-, and three-vessel stenosis were 57%(17/30), 58% (11/19) and 8/8, respectively. All 185 patients who underwent exemise stress MPI were divided into 2 groups according to whether the patients reached the target heart rate or not at the peak of the test. And 53 patients (29%) were group 1 (reached the target heart rate)and 132 patients (71%) were group 2 (did not reach the target heart rate). The sensitivity of group 1 wag higher than that of group 2, but with no

  11. Improving appropriate use of echocardiography and single-photon emission computed tomographic myocardial perfusion imaging: a continuous quality improvement initiative.

    Science.gov (United States)

    Johnson, Thomas V; Rose, Geoffrey A; Fenner, Deborah J; Rozario, Nigel L

    2014-07-01

    Appropriate use criteria for cardiovascular imaging have been published, but compliance in practice has been incomplete, with persistent high rates of inappropriate use. The aim of this study was to show the efficacy of a continuous quality improvement (CQI) initiative to favorably influence the appropriate use of outpatient transthoracic echocardiography and single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (MPI) in a large cardiovascular practice. In this prospective study, a multiphase CQI initiative was implemented, and its impact on ordering patterns for outpatient transthoracic echocardiography and SPECT MPI was assessed. Between November and December 2010, a baseline analysis of the application of appropriate use criteria to indications for outpatient transthoracic echocardiographic studies (n = 203) and SPECT MPI studies (n = 205) was performed, with studies categorized as "appropriate," "inappropriate," "uncertain," or "unclassified." The CQI initiative was then begun, with (1) clinician education, including didactic lectures and case-based presentations with audience participation; (2) system changes in ordering processes, with redesigned image ordering forms; and (3) peer review and feedback. A follow-up analysis was then performed between June and August 2012, with categorization of indications for transthoracic echocardiographic studies (n = 206) and SPECT MPI studies (n = 206). At baseline, 73.9% of echocardiographic studies were categorized as appropriate, 16.7% as inappropriate, 5.9% as uncertain, and 3.4% as unclassified. Similarly, for SPECT MPI studies 71.7% were categorized as appropriate, 18.5% as inappropriate, 7.8% as uncertain, and 1.9% as unclassified. Separate analysis of the two most important categories, appropriate and inappropriate, demonstrated a significant improvement after the CQI initiative, with a 63% reduction in inappropriate echocardiographic studies (18.5% vs 6.9%, P = .0010) and a 46% reduction

  12. The influence of an atmospheric Two-Way coupled model system on the predictability of extratropical cyclones

    Science.gov (United States)

    Schuster, Mareike; Thürkow, Markus; Weiher, Stefan; Kirchner, Ingo; Ulbrich, Uwe; Will, Andreas

    2016-04-01

    A general bias of global atmosphere ocean models, and also of the MPI-ESM, is an under-representation of the high latitude cyclone activity and an overestimation of the mid latitude cyclone activity in the North Atlantic, thus representing the extra-tropical storm track too zonal. We will show, that this effect can be antagonized by applying an atmospheric Two-Way Coupling (TWC). In this study we present a newly developed Two-Way Coupled model system, which is based on the MPI-ESM, and show that it is able to capture the mean storm track location more accurate. It also influences the sub-decadal deterministic predictability of extra-tropical cyclones and shows significantly enhanced skill compared to the "uncoupled" MPI-ESM standalone system. This study evaluates a set of hindcast experiments performed with said Two-Way Coupled model system. The regional model COSMO CLM is Two-Way Coupled to the atmosphere of the global Max-Plack-Institute Earth System Model (MPI-ESM) and therefore integrates and exchanges the state of the atmosphere every 10 minutes (MPI-TWC-ESM). In the coupled source region (North Atlantic), mesoscale processes which are relevant for the formation and early-stage development of cyclones are expected to be better represented, and therefore influence the large scale dynamics of the target region (Europe). The database covers 102 "uncoupled" years and 102 Two-Way Coupled years of the recent climate (1960-2010). Results are validated against the ERA-Interim reanalysis. Besides the climatological point of view, the design of this single model ensemble allows for an analysis of the predictability of the first and second leadyears of the hindcasts. As a first step to understand the improved predictability of cyclones, we will show a detailed analysis of climatologies for specific cyclone categories, sorted by season and region. Especially for cyclones affecting Europe, the TWC is capable to counteract the AOGCM's biases in the North Atlantic. Also

  13. Using WEED to simulate the global wetland distribution in a ESM

    Science.gov (United States)

    Stacke, Tobias; Hagemann, Stefan

    2016-04-01

    Lakes and wetlands are an important land surface feature. In terms of hydrology, they regulate river discharge, mitigate flood events and constitute a significant surface water storage. Considering physical processes, they link the surface water and energy balances by altering the separation of incoming energy into sensible and latent heat fluxes. Finally, they impact biogeochemical processes and may act as carbon sinks or sources. Most global hydrology and climate models regard wetland extent and properties as constant in time. However, to study interactions between wetlands and different states of climate, it is necessary to implement surface water bodies (thereafter referred to as wetlands) with dynamical behavior into these models. Besides an improved representation of geophysical feedbacks between wetlands, land surface and atmosphere, a dynamical wetland scheme could also provide estimates of soil wetness as input for biogeochemical models, which are used to compute methane production in wetlands. Recently, a model for the representation of wetland extent dynamics (WEED) was developed as part of the hydrology model (MPI-HM) of the Max-Planck-Institute for Meteorology (MPI-M). The WEED scheme computes wetland extent in agreement with the range of observations for the high northern latitudes. It simulates a realistic seasonal cycle which shows sensitivity to northern snow-melt as well as rainy seasons in the tropics. Furthermore, flood peaks in river discharge are mitigated. However, the WEED scheme overestimates wetland extent in the Tropics which might be related to the MPI-HM's simplified potential evapotranspiration computation. In order to overcome this limitation, the WEED scheme is implemented into the MPI-M's land surface model JSBACH. Thus, not only its effect on water fluxes can be investigated but also its impact on the energy cycle, which is not included in the MPI-HM. Furthermore, it will be possible to analyze the physical effects of wetlands in a

  14. Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera

    International Nuclear Information System (INIS)

    Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F.; Erlandsson, Kjell; Waddington, Wendy A.; Ell, Peter J.; Sharir, Tali; Roth, Nathaniel; Berman, Daniel S.

    2010-01-01

    We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5±11.8 years of age, 16 men) were injected with 74 MBq of 201 Tl (rest) and 250 MBq 99m Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest 201 Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress 99m Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest 201 Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest 201 Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, p 201 Tl D-SPECT acquisition. (orig.)

  15. Changes in multidimensional pain inventory profile after a pain rehabilitation programme indicate the risk of receiving sick leave benefits one year later

    DEFF Research Database (Denmark)

    Nyberg, Vanja E; Novo, Mehmed; Sjölund, Bengt H.

    2014-01-01

    ,784 patients (709 men and 2,075 women) collected from the Swedish Quality Register for Pain Rehabilitation (SQRP) before and at the end of rehabilitation and compared with independent sick leave data for 1 year later. RESULTS: After rehabilitation there was a significantly decreased share of Dysfunctional...... profiles (DYS) among both men (44% before, 31% after) and women (39% before, 26% after), but an increased share of Adaptive Coper profiles (men 15% before, 24% after, women 14% before, 24% after). The number of patients on full-time sick leave decreased significantly among men (from 57% to 46%) and women......OBJECTIVES: To determine whether coping profile changes after rehabilitation, assessed with the Multidimensional Pain Inventory (MPI), can predict which persons disabled by chronic musculoskeletal pain will be in receipt of sick leave benefits in the long term. METHODS: Study of MPI data from 2...

  16. NT-proBNP and Circulating Inflammation Markers in Prediction of a Normal Myocardial Scintigraphy in Patients with Symptoms of Coronary Artery Disease

    DEFF Research Database (Denmark)

    Rathcke, C.N.; Kjøller, Erik; Fogh-Andersen, N.

    2010-01-01

    with an intermediate risk of CAD or with known CAD with renewed suspicion of ischemia were referred to MPI. Blood samples were analyzed for N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP), YKL-40, IL-6, matrix metalloproteinase 9 (MMP-9) and high sensitive C-reactive protein (hs......CRP). Patients with myocardial perfusion defects had elevated levels of NT-proBNP (p95% regardless of existing CAD. Conclusions: 20-25% of patients suspected of CAD could have been spared a MPI by using a NT-proBNP cut-off concentration at 25 ng/l with a negative predictive value >95%. NT-proBNP has...

  17. Observer variability in the evaluation of dual-isotope Tl-201/Tc-99m sestamibi rest/stress myocardial perfusion SPECT in men and women with known or suspected stable angina pectoris

    DEFF Research Database (Denmark)

    Johansen, Allan; Høilund-Carlsen, Poul Flemming; Christensen, Henrik Wulff

    2004-01-01

    BACKGROUND: Observer variability of dual-isotope myocardial perfusion imaging (MPI) with single photon emission computed tomography has rarely been investigated. The aim of our study was to evaluate the interpretive reproducibility with this technique. METHODS AND RESULTS: We report on 507 patients...... rate of abnormal MPI was 49% (59% in men and 34% in women). The interobserver agreement for the whole group (kappa = 0.85) and for men and women separately (kappa = 0.86 and 0.82, respectively) was excellent with regard to the overall diagnosis (normal, reversible, or fixed defects) as well as left...... anterior descending and left circumflex artery vascular territories (kappa = 0.85 and 0.82, respectively). However, in the right coronary artery territory, agreement was excellent in men (kappa = 0.83) but moderate in women (kappa = 0.57). CONCLUSIONS: In a relatively large group of men and women...

  18. WOMBAT: A Scalable and High-performance Astrophysical Magnetohydrodynamics Code

    Energy Technology Data Exchange (ETDEWEB)

    Mendygral, P. J.; Radcliffe, N.; Kandalla, K. [Cray Inc., St. Paul, MN 55101 (United States); Porter, D. [Minnesota Supercomputing Institute for Advanced Computational Research, Minneapolis, MN USA (United States); O’Neill, B. J.; Nolting, C.; Donnert, J. M. F.; Jones, T. W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Edmon, P., E-mail: pjm@cray.com, E-mail: nradclif@cray.com, E-mail: kkandalla@cray.com, E-mail: oneill@astro.umn.edu, E-mail: nolt0040@umn.edu, E-mail: donnert@ira.inaf.it, E-mail: twj@umn.edu, E-mail: dhp@umn.edu, E-mail: pedmon@cfa.harvard.edu [Institute for Theory and Computation, Center for Astrophysics, Harvard University, Cambridge, MA 02138 (United States)

    2017-02-01

    We present a new code for astrophysical magnetohydrodynamics specifically designed and optimized for high performance and scaling on modern and future supercomputers. We describe a novel hybrid OpenMP/MPI programming model that emerged from a collaboration between Cray, Inc. and the University of Minnesota. This design utilizes MPI-RMA optimized for thread scaling, which allows the code to run extremely efficiently at very high thread counts ideal for the latest generation of multi-core and many-core architectures. Such performance characteristics are needed in the era of “exascale” computing. We describe and demonstrate our high-performance design in detail with the intent that it may be used as a model for other, future astrophysical codes intended for applications demanding exceptional performance.

  19. A data base for on-line event analysis on a distributed memory machine

    International Nuclear Information System (INIS)

    Argante, E.; Meesters, M.R.J.; Willers, I.; Stok, P. van der

    1996-01-01

    Parallel in-memory databases can enhance the structuring and parallelization of programs used in High Energy Physics (HEP). Efficient database access routines are used as communication primitives which hide the communication topology in contrast to the more explicit communications like PVM or MPI. A parallel in-memory database, called SPIDER, has been implemented on a 32 node Meiko CS-2 distributed memory machine. The SPIDER primitives generate a lower overhead than the one generated by PVM or MPI. The even reconstruction program, CPREAD, of the CLEAR experiment, has been used as test case. Performance measurements showed that CPREAD interfaced to SPIDER can easily cope with the event rate generated by CPLEAR. (author)

  20. Multi-point injection demonstration for solidification of shallow buried waste at Oak Ridge Reservation, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1996-10-01

    The multi-point injection (MPI) technology is a precision, high-velocity jetting process for the in situ delivery of various agents to treat radiological and/or chemical wastes. A wide variety of waste forms can be treated, varying from heterogeneous waste dumped into shallow burial trenches to contaminated soils consisting of sands/gravels, silts/clays and soft rock. The robustness of the MPI system is linked to its broad range of applications which vary from in situ waste treatment to creation of both vertical and horizontal barriers. The only major constraint on the type of in situ treatment which can be delivered by the NTI system is that agents must be in a slurry form