678 research outputs found

    GLB: Lifeline-based Global Load Balancing library in X10

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    We present GLB, a programming model and an associated implementation that can handle a wide range of irregular paral- lel programming problems running over large-scale distributed systems. GLB is applicable both to problems that are easily load-balanced via static scheduling and to problems that are hard to statically load balance. GLB hides the intricate syn- chronizations (e.g., inter-node communication, initialization and startup, load balancing, termination and result collection) from the users. GLB internally uses a version of the lifeline graph based work-stealing algorithm proposed by Saraswat et al. Users of GLB are simply required to write several pieces of sequential code that comply with the GLB interface. GLB then schedules and orchestrates the parallel execution of the code correctly and efficiently at scale. We have applied GLB to two representative benchmarks: Betweenness Centrality (BC) and Unbalanced Tree Search (UTS). Among them, BC can be statically load-balanced whereas UTS cannot. In either case, GLB scales well-- achieving nearly linear speedup on different computer architectures (Power, Blue Gene/Q, and K) -- up to 16K cores

    A functional type I topoisomerase from Pseudomonas aeruginosa

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    <p>Abstract</p> <p>Background</p> <p><it>Pseudomonas aeruginosa </it>encodes a putative topoisomerase with sequence similarity to the eukaryotic type IB topoisomerase from Vaccinia virus. Residues in the active site are conserved, notably Tyr292 which would be predicted to form the transient covalent bond to DNA.</p> <p>Results</p> <p>The gene encoding the <it>P. aeruginosa </it>topoisomerase I was cloned and expressed in <it>E. coli</it>. The enzyme relaxes supercoiled DNA, while a mutant containing a Tyr292 to Phe substitution at the active site was found to be catalytically inert. This is consistent with the role of Tyr in forming the covalent intermediate. Like Vaccinia topoisomerase, the <it>P. aeruginosa topoisomerase </it>relaxes DNA in the absence of ATP, but unlike Vaccinia topoisomerase, <it>P. aeruginosa </it>topoisomerase does not relax supercoiled DNA without MgCl<sub>2 </sub>present. In addition, high concentration of NaCl is not able to substitute for MgCl<sub>2 </sub>as seen for Vaccinia topoisomerase. A truncated derivative of the topoisomerase lacking residues 1–98 relaxes DNA, with both full length and truncated enzyme exhibiting equivalent requirements for divalent cations and the ability to relax DNA to completion, suggesting a shared domain organization. DNA-binding assays suggest an only modest preference for the CCCTT pentameric sequence required for transesterification by Vaccinia topoisomerase IB.</p> <p>Conclusion</p> <p><it>P. aeruginosa </it>encodes a functional topoisomerase with significant similarity to the type IB enzyme encoded by poxviruses. In contrast to the Vaccinia-encoded homolog, the <it>P. aeruginosa</it>-encoded enzyme requires divalent cations for catalytic activity, relaxes DNA to completion, and does not exhibit a strong preference for the pentameric sequence stringently required by the Vaccinia-encoded homolog. A comparison with the structure of poxviral topoisomerase in complex with DNA suggests that bacterial homologs of the eukaryotic type IB topoisomerase may exhibit a relaxed sequence preference due to the lack of conservation of certain residues involved in sequence-specific DNA contacts, and that interaction with an only modestly preferred sequence may result in suboptimal positioning of catalytic residues.</p

    Energy consumption characterization in precision hard machining using CBN cutting tools

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    In this paper, the contribution of tool wear to the energy balance was determined for precision hard turning using chamfered CBN cutting tools. The tool nose wear VBC and the corresponding changes of component forces Fc, Ff and Fp resulting from tool wear evolution were continuously measured during wear tests. Based on the cutting mechanics, specific cutting and ploughing energies were calculated for a number of tool wear states. In particular, changes of energy balance due to tool wear under variable feed rate, depth of cut and tool nose radius were discussed. A distinction between material removal conditions resulting from precision cutting and grinding at a very low uncut chip thickness is considered. © 2015, The Author(s)

    Long term cognitive outcomes of early term (37-38 weeks) and late preterm (34-36 weeks) births: a systematic review

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    Background: There is a paucity of evidence regarding long-term outcomes of late preterm (34-36 weeks) and early term (37-38 weeks) delivery.  The objective of this systematic review was to assess long-term cognitive outcomes of children born at these gestations. Methods: Four electronic databases (Medline, Embase, clinicaltrials.gov and PsycINFO) were searched.  Last search was 5 th August 2016.  Studies were included if they reported gestational age, IQ measure and the ages assessed.  The protocol was registered with the International prospective register of systematic reviews (PROSPERO Record CRD42015015472).  Two independent reviewers assessed the studies.  Data were abstracted and critical appraisal performed of eligible papers. Results: Of 11,905 potential articles, seven studies reporting on 41,344 children were included.  For early term births, four studies (n = 35,711) consistently showed an increase in cognitive scores for infants born at full term (39-41 weeks) compared to those born at early term (37-38 weeks) with increases for each week of term (difference between 37 and 40 weeks of around 3 IQ points), despite differences in age of testing and method of IQ/cognitive testing.  Four studies (n = 5644) reporting childhood cognitive outcomes of late preterm births (34 - 36 weeks) also differed in study design (cohort and case control); age of testing; and method of IQ testing, and found no differences in outcomes between late preterm and term births, although risk of bias was high in included studies. Conclusion:  Children born at 39-41 weeks have higher cognitive outcome scores compared to those born at early term (37-38 weeks).  This should be considered when discussing timing of delivery.  For children born late preterm, the data is scarce and when compared to full term (37-42 weeks) did not show any difference in IQ scores

    The Ursinus Weekly, December 18, 1916

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    Schaff anniversary observed on Friday • Memorial service for late Mr. Dimon • Ursinus quintet loses to Temple • Christmas in Hawaii • College directory • A Christmas hymn: the Christ child • Resolutions • On the campushttps://digitalcommons.ursinus.edu/weekly/2575/thumbnail.jp

    Predicting Seasonal and Spatial Onset of cHABs in Polymictic Reservoirs

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    Cyanobacterial Harmful Algal Blooms (cHABS) are a naturally occurring but increasingly common phenomenon due to anthropogenic activities and climate change. cHABs reduce water quality by forming unsightly surface scums and sometimes producing algal matts on the surface of water bodies, reduce water quality, and in high densities can produce cyanotoxins that can harm humans, pets, and wildlife. Ecological forecasting of cHABs has proved elusive in part because the in-situ fluorometric methods currently employed for detecting cyanobacteria cells are subject to varied interference as water quality and the biotic community changes. In this study we seek to develop an ecological forecasting capability that overcomes both temporally and spatially derived in-situ fluorometric interferences. We obtained water samples at 26 polymictic reservoirs over a two-day period and at five polymictic reservoirs weekly during the summer of 2019. Collected water samples are being used for quantitative analysis of cyanobacterial cell densities by means of qPCR. We plan a data reduction technique (e.g. PCA, VIF screening, elastic-net regression as appropriate) followed by multivariate predictive model (e.g. multiple regression, ordination, discriminant analysis as appropriate)

    Thermally Activated Magnetization and Resistance Decay during Near Ambient Temperature Aging of Co Nanoflakes in a Confining Semi-metallic Environment

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    We report the observation of magnetic and resistive aging in a self assembled nanoparticle system produced in a multilayer Co/Sb sandwich. The aging decays are characterized by an initial slow decay followed by a more rapid decay in both the magnetization and resistance. The decays are large accounting for almost 70% of the magnetization and almost 40% of the resistance for samples deposited at 35 oC^oC. For samples deposited at 50 oC^oC the magnetization decay accounts for ∼50\sim 50% of the magnetization and 50% of the resistance. During the more rapid part of the decay, the concavity of the slope of the decay changes sign and this inflection point can be used to provide a characteristic time. The characteristic time is strongly and systematically temperature dependent, ranging from ∼1\sim1x102s10^2 s at 400K to ∼3\sim3x105s10^5 s at 320K in samples deposited at 35oC35 ^oC. Samples deposited at 50 oC^oC displayed a 7-8 fold increase in the characteristic time (compared to the 35oC35 ^oC samples) for a given aging temperature, indicating that this timescale may be tunable. Both the temperature scale and time scales are in potentially useful regimes. Pre-Aging, Scanning Tunneling Microscopy (STM) reveals that the Co forms in nanoscale flakes. During aging the nanoflakes melt and migrate into each other in an anisotropic fashion forming elongated Co nanowires. This aging behavior occurs within a confined environment of the enveloping Sb layers. The relationship between the characteristic time and aging temperature fits an Arrhenius law indicating activated dynamics

    Birth weight and cognitive ability in adulthood:A systematic review and meta-analysis

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    Birth weight is associated with a range of adult health outcomes. In childhood, there is a positive association between birth weight – in the normal range (&gt; 2500 g) – and cognitive ability, but no systematic review has yet assessed this effect across adult life. We aimed to synthesise published studies assessing the relationship between birth weight and general cognitive ability in non-clinical adult populations (≥ 18 years). Nineteen studies (N = 1.122,858), mean participant age ranged from 18 to 78.4 years, fulfilled the inclusion criteria, of which eight could be included in a random-effects meta-analysis. Birth weight was associated with cognitive ability in adulthood, with each kilogram increase in birth weight associated with a 0.13 SD increase in general or fluid intelligence (95% CI [0.07, 0.19]). There was considerable heterogeneity in the effect size (I2 = 97.8%, 95% CI [97.2, 98.4], p &lt; 0.001). The association was similar after correcting for gestational age and parental social class where data were available. The effect size was larger for participants aged &lt; 60 years than those aged 60 years or over. There is a modest association between birth weight and cognitive ability in adulthood that may diminish at older ages

    Identification Of A Germline F692L Drug Resistance Variant In Cis With Flt3-ITD In Knock-In Mice

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    Letter to the Editor.-- Dovey, Oliver M. et al.Internal tandem duplication (ITD) mutations in the juxtamembrane domain of the fms-like tyrosine kinase 3 (FLT3) gene occur in approximately one quarter of cases of acute myeloid leukemia (AML), are associated with constitutive activation of the kinase and confer a poor prognosis.BC is funded by the >China Scholarship Council> for his visiting studies in UK. AM is funded by the Kay Kendall Leukaemia Fund project grant. CG was funded by a Bloodwise Clinical Research Training Fellowship. IV is funded by Spanish Ministerio de Economía y Competitividad subprograma Ramón y Cajal. We thank Servicio Santander Supercomputación for their support. OMD, JLC and GSV are funded by a Wellcome Trust Senior Fellowship in Clinical Science (WT095663MA) and this work was also funded by the Wellcome Trust Sanger InstitutePeer Reviewe
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