7,438 research outputs found

    VALUE AND VALUES - WHAT MOTIVATES CORPORATE CITIZENSHIP IN SOUTH AFRICA?

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    The expectation that business has a responsibility to the immediate communities in which they operate and to national development imperatives has become entrenched in society. Globally, businesses have responded by embracing the discourse and practice of corporate social responsibility (CSR), albeit at different levels. Such responses have been shaped by local business cultures and the national economic and political contexts.The discourse on CSR or corporate social investment (CSI) has ascended to global prominence, and there are numerous definitions of what it consists of. However, emerging and common themes point towards legislative compliance, meeting stakeholder expectations and contributing to the upliftment of the broader society while increasing and sustaining business profitability

    Additional Records of Acanthocephalan Parasites from Arkansas Fishes, with New Records from Missouri Fishes

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    Over the last decade, our research consortium has provided information on acanthocephalan parasites of Arkansas vertebrates, including records from some of the state’s fishes. Here, we continue to provide data on new geographic and new host records of acanthocephalans from Arkansas fishes. In addition, for the first time, we report records of acanthocephalans for some Missouri fishes. We document 2 new state records as well as 10 new host records for some fish acanthocephalans

    Cool Core Bias in Sunyaev-Zel'dovich Galaxy Cluster Surveys

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    Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01% - 10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~ 6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees.Comment: 8 pages, 4 figures, accepted to Ap

    Community Versus the Imperial Mind: Images of Civil Strife in Hawthorne\u27s The Marble Faun .

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    Nathaniel Hawthorne\u27s The Marble Faun allegorically represents the crisis of civil order in the American Republic in the 1850s foreshadowing the Civil War that erupted a year after the novel\u27s publication. Hawthorne\u27s last completed romance, set in Rome, suggests Americans must judge themselves against the community and continuity embodied in the European culture they had recently cast off. Challenging Emerson\u27s doctrine that man may have an original relationship to history and the Creator, Hawthorne undermines the Founders\u27 great idea: that an assembly of men could discover and formulate--in an act of the human mind--self-evident, inalienable rights that govern political and social relations. The first and second chapters place Hawthorne and the four protagonists of the novel in the historical context of civil strife. Chapter Three shows Miriam as an Emersonian, bound only to her intuitions, embodying millennial impulses which threaten to tear society apart. Chapter Four suggests multiple ironic links between Miriam\u27s leading Donatello into the murder of her Model and the actions of Transcendental thinkers who supported both the Italian Risorgimento and the American Abolitionist struggle. Hawthorne poses images of communal response and penance against this perfectionist violence. The fifth chapter describes Hilda\u27s shunning of Miriam as one expression of communal obligations to her, followed by other self-sacrificial acts. Hilda seeks and creates community, combining obedience to transcendent value with human norms in a way that associates her with St. Hilda of Whitby and the Virgin Mary. Kenyon\u27s associations with his American and British namesakes are likewise explored. The sixth chapter examines metaphors of the gothic cathedral and Saint Peter\u27s Basilica as models of communal perception. The Pantheon is employed as a contrasting metaphor of a pagan, isolating character. The cathedral is the climactic metaphor for community in The Marble Faun, the image of macrocosmic harmony, just as the anticipated marriage of Kenyon and Hilda establishes microcosmic harmony. The multiple works of art in the novel thus create a set of alternative visions that unite the claims of the personal and the communal; the American and the European; the temporal and the eternal

    Stellar Activity and its Implications for Exoplanet Detection on GJ 176

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    We present an in-depth analysis of stellar activity and its effects on radial velocity (RV) for the M2 dwarf GJ 176 based on spectra taken over 10 years from the High Resolution Spectrograph on the Hobby-Eberly Telescope. These data are supplemented with spectra from previous observations with the HIRES and HARPS spectrographs, and V- and R-band photometry taken over 6 years at the Dyer and Fairborn observatories. Previous studies of GJ 176 revealed a super-Earth exoplanet in an 8.8-day orbit. However, the velocities of this star are also known to be contaminated by activity, particularly at the 39-day stellar rotation period. We have examined the magnetic activity of GJ 176 using the sodium I D lines, which have been shown to be a sensitive activity tracer in cool stars. In addition to rotational modulation, we see evidence of a long-term trend in our Na I D index, which may be part of a long-period activity cycle. The sodium index is well correlated with our RVs, and we show that this activity trend drives a corresponding slope in RV. Interestingly, the rotation signal remains in phase in photometry, but not in the spectral activity indicators. We interpret this phenomenon as the result of one or more large spot complexes or active regions which dominate the photometric variability, while the spectral indices are driven by the overall magnetic activity across the stellar surface. In light of these results, we discuss the potential for correcting activity signals in the RVs of M dwarfs.Comment: Accepted for publication in Ap

    Protein kinase C modulates the activity of a cloned gamma-aminobutyric acid transporter expressed in Xenopus oocytes via regulated subcellular redistribution of the transporter

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    We report that activators and inhibitors of protein kinase C (PKC) and protein phosphatases regulate the activity of a cloned rat brain gamma- aminobutyric acid (GABA) transporter (GAT1) expressed in Xenopus oocytes. Four compounds known to activate PKC increased GABA uptake 2- 3.5-fold over basal control levels. Inhibition of PKC by bisindolylmaleimide reduced basal GABA uptake 80% and blocked the phorbol 12-myristate 13-acetate (PMA)-induced stimulation of transport. Okadaic acid, a protein phosphatase inhibitor, stimulated transport 2.5- fold; a 4-fold increase in GABA uptake occurred when oocytes were treated with cyclosporin A, a specific inhibitor of protein phosphatase 2B. Modulation resulted in changes to Vmax but not to Km and was influenced by the functional expression level of the transporter protein; as expression level increased, the ability to up-regulate transporter activity decreased. Down-regulation of transporter activity was independent of expression level. Modulation did not occur through phosphorylation of the three consensus PKC sites predicted by the primary protein sequence since their removal had no effect on the susceptibility of the transporter to modulation by PMA or bisindolylmaleimide. Subcellular fractionation of oocyte membranes demonstrated that under basal level conditions, the majority of GAT1 was targeted to a cytoplasmic compartment corresponding to the trans- Golgi or low density vesicles. Stimulation of PKC with PMA resulted in a translocation of transporters from this compartment to the plasma membrane. At higher expression levels of GAT1 protein, a larger portion of GAT1 was found on the plasma membrane during basal level conditions and treatment with bisindolylmaleimide resulted in removal of these transporters from the plasma membrane. At expression levels demonstrated to be resistant to modulation by PMA, PMA-treatment still resulted in translocation of transporters from the cytoplasm to the plasma membrane. Thus, the inability of PMA to increase uptake at high expression of the GAT1 protein is due to saturation at a step subsequent to translocation. These findings 1) demonstrate the presence of a novel regulated secretory pathway in oocytes and 2) suggest a modulatory mechanism for neurotransmitter transporters that could have significant effects upon synaptic function

    Differential coupling of G protein alpha subunits to seven-helix receptors expressed in Xenopus oocytes

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    Xenopus oocytes were used to examine the coupling of the serotonin 1c (5HT1c) and thyrotropin-releasing hormone (TRH) receptors to both endogenous and heterologously expressed G protein alpha subunits. Expression of either G protein-coupled receptor resulted in agonist- induced, Ca(2+)-activated Cl- currents that were measured using a two- electrode voltage clamp. 5HT-induced Cl- currents were reduced 80% by incubating the injected oocytes with pertussis toxin (PTX) and inhibited 50-65% by injection of antisense oligonucleotides to the PTX- sensitive Go alpha subunit. TRH-induced Cl- currents were reduced only 20% by PTX treatment but were inhibited 60% by injection of antisense oligonucleotides to the PTX-insensitive Gq alpha subunit. Injection of antisense oligonucleotides to a novel Xenopus phospholipase C-beta inhibited the 5HT1c (and Go)-induced Cl- current with little effect on the TRH (and Gq)-induced current. These results suggest that receptor- activated Go and Gq interact with different effectors, most likely different isoforms of phospholipase C-beta. Co-expression of each receptor with seven different mammalian G protein alpha subunit cRNAs (Goa, Gob, Gq, G11, Gs, Golf, and Gt) was also examined. Co-expression of either receptor with the first four of these G alpha subunits resulted in a maximum 4-6-fold increase in Cl- currents; the increase depended on the amount of G alpha subunit cRNA injected. This increase was blocked by PTX for G alpha oa and G alpha ob co-expression but not for G alpha q or G alpha 11 co-expression. Co-expression of either receptor with Gs, Golf, or Gt had no effect on Ca(2+)-activated Cl- currents; furthermore, co-expression with Gs or Golf also failed to reveal 5HT- or TRH-induced changes in adenylyl cyclase as assessed by activation of the cystic fibrosis transmembrane conductance regulator Cl- channel. These results indicate that in oocytes, the 5HT1c and TRH receptors do the following: 1) preferentially couple to PTX-sensitive (Go) and PTX-insensitive (Gq) G proteins and that these G proteins act on different effectors, 2) couple within the same cell type to several different heterologously expressed G protein alpha subunits to activate the oocyte's endogenous Cl- current, and 3) fail to couple to G protein alpha subunits that activate cAMP or phosphodiesterase

    Fidelity enhancement by logical qubit encoding

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    We demonstrate coherent control of two logical qubits encoded in a decoherence free subspace (DFS) of four dipolar-coupled protons in an NMR quantum information processor. A pseudo-pure fiducial state is created in the DFS, and a unitary logical qubit entangling operator evolves the system to a logical Bell state. The four-spin molecule is partially aligned by a liquid crystal solvent, which introduces strong dipolar couplings among the spins. Although the system Hamiltonian is never fully specified, we demonstrate high fidelity control over the logical degrees of freedom. In fact, the DFS encoding leads to higher fidelity control than is available in the full four-spin Hilbert space.Comment: 10 pages, 2 figure
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