766 research outputs found

    Garbage collection auto-tuning for Java MapReduce on Multi-Cores

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    MapReduce has been widely accepted as a simple programming pattern that can form the basis for efficient, large-scale, distributed data processing. The success of the MapReduce pattern has led to a variety of implementations for different computational scenarios. In this paper we present MRJ, a MapReduce Java framework for multi-core architectures. We evaluate its scalability on a four-core, hyperthreaded Intel Core i7 processor, using a set of standard MapReduce benchmarks. We investigate the significant impact that Java runtime garbage collection has on the performance and scalability of MRJ. We propose the use of memory management auto-tuning techniques based on machine learning. With our auto-tuning approach, we are able to achieve MRJ performance within 10% of optimal on 75% of our benchmark tests

    Study of One-nucleon Transfer Reactions

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    The structure of nuclei away from the line of stability and near the driplines in the nuclear chart has been of huge interest since the arrival of radioactive ion beam facilities. The properties of nuclei evolve as a function of proton and neutron numbers and understanding the mechanisms behind this is one of the keys to explaining the strong nuclear force. Single-nucleon transfer reactions using deuteron targets are powerful probes of nuclear structure when the emitted proton or neutron is measured with high fidelity. A variety of structure phenomena are observed in the beryllium isotopes marking them particularly attractive for nuclear structure studies. The structure of 13Be offers insights into the N=8 shell gap, the nature of the Borromean nucleus 14Be, the influence of the continuum, and the nature of neutron drip-line nuclei. However, despite the significant number of experiments performed over the last three decades, the energies and ordering of the low-lying resonances are less certain. A 12Be(d,p)13Be transfer reaction was performed in inverse kinematics at ISAC II at TRIUMF. The 12Be beam at 9.5 MeV/u interacted with the novel IRIS solid D2 target, and ejectiles and recoils were detected in an annular silicon detector array and two ΔE - E telescopes, respectively. A Q-value plot showing the population of resonances in the 13Be continuum was obtained, and it was fitted using GEANT4 simulations in combination with Bayesian optimization. An angular distribution of the lowest-lying strength in 13Be was obtained, and it was fitted with DWBA calculations using different combinations of optical model potentials. Results from this work will be presented here, along with interpretations of five previous works performed on 13Be, in comparison with our data. The NEXT detector is a novel, high precision, segmented neutron detector which offers excellent position and timing resolution. It uses a pulse shape discriminating plastic scintillator, which is crucial in identifying neutrons from a gamma-ray background in reaction experiments. A 20Ne(d,n)21Na proton transfer reaction was performed at ReA6 at NSCL to benchmark this detector for reaction experiment studies. The details and preliminary results of this experiment will also be presented

    When a crisis hits: be resilient and a catalyst for positive change

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    When facing a crisis, leaders need to take a thoughtful, positive, resilient, and transformative approach to crisis management. However, they often do the opposite, denying and minimising the problem, or reactively taking action that escalates the situation. Sarah Kovoor-Misra describes four key capabilities that can help organisations not only prevent or quickly contain damage, but strengthen trust, gain new insights, and emerge with capacities that can help them cope more effectively with future crises and challenges

    Threonine 180 Is Required for G-protein-coupled Receptor Kinase 3- and β-Arrestin 2-mediated Desensitization of the µ-Opioid Receptor in Xenopus Oocytes

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    To determine the sites in the µ-opioid receptor (MOR) critical for agonist-dependent desensitization, we constructed and coexpressed MORs lacking potential phosphorylation sites along with G-protein activated inwardly rectifying potassium channels composed of Kir3.1 and Kir3.4 subunits in Xenopus oocytes. Activation of MOR by the stable enkephalin analogue, [D-Ala2,MePhe4,Glyol5]enkephalin, led to homologous MOR desensitization in oocytes coexpressing both G-protein-coupled receptor kinase 3 (GRK3) and beta -arrestin 2 (arr3). Coexpression with either GRK3 or arr3 individually did not significantly enhance desensitization of responses evoked by wild type MOR activation. Mutation of serine or threonine residues to alanines in the putative third cytoplasmic loop and truncation of the C-terminal tail did not block GRK/arr3-mediated desensitization of MOR. Instead, alanine substitution of a single threonine in the second cytoplasmic loop to produce MOR(T180A) was sufficient to block homologous desensitization. The insensitivity of MOR(T180A) might have resulted either from a block of arrestin activation or arrestin binding to MOR. To distinguish between these alternatives, we expressed a dominant positive arrestin, arr2(R169E), that desensitizes G protein-coupled receptors in an agonist-dependent but phosphorylation-independent manner. arr2(R169E) produced robust desensitization of MOR and MOR(T180A) in the absence of GRK3 coexpression. These results demonstrate that the T180A mutation probably blocks GRK3- and arr3-mediated desensitization of MOR by preventing a critical agonist-dependent receptor phosphorylation and suggest a novel GRK3 site of regulation not yet described for other G-protein-coupled receptors

    Management Training Needs Assessment United Methodist Community Centers

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    This report outlines a management training plan for the United Methodist Community Centers, Inc. (UMCC). UMCC is a community service agency which focuses on bringing positive change for minorities and other disadvantaged people in the Omaha community. UMCC is one of Omaha\u27s major community service agencies and has two locations, the Wesley House in north Omaha and the Woodson Center in south Omaha. A broad range of community programs are coordinated and managed from these two centers, including, for example: family enhancement programs, a woman\u27s resource center, sweat equity housing development, senior meals programs, pre-school and after-school learning programs, and a variety of other youth activities

    Regulator of G protein signaling 9-2 (RGS9-2) mRNA is up regulated during neuronal differentiation of mouse embryonic stem cells

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    In this study we demonstrate up-regulation of mRNA for Regulator of G protein Signaling (RGS) 6, 7, 9 and 11, R7 family RGS binding protein (R7BP) and RGS9 anchor protein (R9AP) during neuronal differentiation of mouse embryonic stem cells (mESCs). This expression pattern was most robust for RGS9 whose transcript level was low in undifferentiated mESCs but increased over 125 fold when differentiating mESCs began to exhibit a neuronal precursor cell (NPC) phenotype. In addition, we demonstrate that RGS9 mRNA is expressed in neuronal stem cells isolated from embryonic mouse cortex. The expression of RGS9 in two distinct populations of NPCs suggests that RGS9 and its accessory proteins may play an important role in neuron development

    Co-expression of Gbeta 5 Enhances the Function of Two Ggamma Subunit-like Domain-containing Regulators of G Protein Signaling Proteins

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    Regulators of G protein signaling (RGS) stimulate the GTPase activity of G protein Galpha subunits and probably play additional roles. Some RGS proteins contain a Ggamma subunit-like (GGL) domain, which mediates a specific interaction with Gbeta 5. The role of such interactions in RGS function is unclear. RGS proteins can accelerate the kinetics of coupling of G protein-coupled receptors to G-protein-gated inwardly rectifying K+ (GIRK) channels. Therefore, we coupled m2-muscarinic acetylcholine receptors to GIRK channels in Xenopus oocytes to evaluate the effect of Gbeta 5 on RGS function. Co-expression of either RGS7 or RGS9 modestly accelerated GIRK channel kinetics. When Gbeta 5 was co-expressed with either RGS7 or RGS9, the acceleration of GIRK channel kinetics was strongly increased over that produced by RGS7 or RGS9 alone. RGS function was not enhanced by co-expression of Gbeta 1, and co-expression of Gbeta 5 alone had no effect on GIRK channel kinetics. Gbeta 5 did not modulate the function either of RGS4, an RGS protein that lacks a GGL domain, or of a functional RGS7 construct in which the GGL domain was omitted. Enhancement of RGS7 function by Gbeta 5 was not a consequence of an increase in the amount of plasma membrane or cytosolic RGS7 protein

    Public attitudes towards automated external defibrillators: results of a survey in the Australian general population

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    BackgroundSwift defibrillation by lay responders using automated external defibrillators (AEDs) increases survival in out-of-hospital cardiac arrest (OHCA). This study evaluated newly designed yellow–red vs. commonly used green–white signage for AEDs and cabinets and assessed public attitudes to using AEDs during OHCA.MethodsNew yellow–red signage was designed to enable easy identification of AEDs and cabinets. A prospective, cross-sectional study of the Australian public was conducted using an electronic, anonymised questionnaire between November 2021 and June 2022. The validated net promoter score investigated public engagement with the signage. Likert scales and binary comparisons evaluated preference, comfort and likelihood of using AEDs for OHCA.ResultsThe yellow–red signage for AED and cabinet was preferred by 73.0% and 88%, respectively, over the green–white counterparts. Only 32% were uncomfortable with using AEDs, and only 19% indicated a low likelihood of using AEDs in OHCA.ConclusionThe majority of the Australian public surveyed preferred yellow–red over green–white signage for AED and cabinet and indicated comfort and likelihood of using AEDs in OHCA. Steps are necessary to standardise yellow–red signage of AED and cabinet and enable widespread availability of AEDs for public access defibrillation

    Membrane Anchor R9AP Potentiates GTPase-accelerating Protein Activity of RGS11·Gβ\u3csub\u3e5\u3c/sub\u3e Complex and Accelerates Inactivation of the mGluR6-G\u3csub\u3e0\u3c/sub\u3e Signaling

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    The R7 subfamily of RGS proteins critically regulates neuronal G protein-signaling pathways that are essential for vision, nociception, motor coordination, and reward processing. A member of the R7 RGS family, RGS11, is a GTPase-accelerating protein specifically expressed in retinal ON-bipolar cells where it forms complexes with the atypical G protein β subunit, Gβ5, and transmembrane protein R9AP. Association with R9AP has been shown to be critical for the proteolytic stability of the complex in the retina. In this study we report that R9AP can in addition stimulate the GTPase-accelerating protein activity of the RGS11·Gβ5 complex at Gαo. Single turnover GTPase assays reveal that R9AP co-localizes RGS11·Gβ5 and Gαo on the membrane and allosterically potentiates the GTPase-accelerating function of RGS11·Gβ5. Reconstitution of mGluR6-Gαo signaling in Xenopus oocytes indicates that RGS11·Gβ5-mediated GTPase acceleration in this system requires co-expression of R9AP. The results provide new insight into the regulation of mGluR6-Gαo signaling by the RGS11·Gβ5·R9AP complex and establish R9AP as a general GTPase-accelerating protein activity regulator of R7 RGS complexes

    Plasma Membrane Compartmentalization of D2 Dopamine Receptors

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    Plasma membrane microcompartments could allow different signaling pathways to operate more efficiently and prevent cross-talk. We utilized a novel in-cell biotin transfer assay to demonstrate that the majority of plasma membrane-expressed D2 dopamine receptor (D2R) is microcompartmentalized within detergent-resistant structures. Conversely, a minority of D2R existed in a detergent-soluble form and interacted in a relatively unrestricted manner with other cellular proteins. The microcompartmentalization of D2R had functional consequences because dopamine-induced internalization of D2R was largely restricted to the compartmentalized receptor. The D2R-containing microcompartments did not correspond to putative detergent-resistant lipid raft structures. First, the detergent-insoluble D2R structures were significantly denser than detergent-resistant membrane fragments containing flotillin, a widely utilized lipid raft marker protein. Second, the detergent solubility of D2R was unaffected by treatment of cells with the cholesterol chelating agent, methyl-β-cyclodextrin, that is thought to disrupt lipid rafts. Finally, the in-cell biotinylation assay did not provide any evidence for the membrane compartmentalization of peptide motifs thought to target to lipid rafts. Thus, our observations form one of the first demonstrations, in living cells, of plasma membrane microcompartments defined by the ability of the compartment structure to broadly restrict the interaction of resident molecules with other cellular proteins
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