479 research outputs found

    Crude Ambitions: The Internationalization of Emerging National Oil Companies

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    The burgeoning literature on the internationalization of emerging country NOCs asserts that the combination of technology transfer in the 1970s-80s and sustained high oil prices in the 1990s created an unprecedented opportunity in the 2000s for NOCs to internationalize their operations at a rapid pace, enabling them to compete successfully with International Oil Companies (IOCs) for dominance in global oil markets. The 2000s has indeed witnessed the expansion of emerging country NOCs' investment, exploration, production, and personnel abroad. And yet, this widespread ambition to internationalize has been realized with varying levels of success. We capture this variation by developing an original composite index that assigns NOCs a degree of internationalization score. We then provide an alternative explanation for why emerging country NOCs achieve such different levels of success. Contrary to existing explanations that emphasize structural and economic changes at the international level, we argue that an NOC's capacity to internationalize is constrained by domestic politics; more specifically, the legacy of its mode of emergence, the timing of convergence between the government and NOC management regarding the merits of internationalization, and the sequencing of sectoral reforms vis-à-vis convergence. Ohio State University. Mershon Center for International Security Studies.Event Web Page, photo

    Central Asia and the globalisation of the contemporary legal consciousness

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    What is the logic which governs the processes of legal globalization? How does the transnational proliferation of legal forms operate in the contemporary geo-juridical space? What are the main defining characteristics of the currently dominant mode of transnational legal consciousness and how can the concept of legal consciousness help us understand better the historical ebb and flow of the Western-led projects of good governance promotion in regions like Central Asia after the fall of the Soviet Union? Using Duncan Kennedy’s seminal essay Three Globalizations of Law and Legal Thought as its starting platform, this essay seeks to explore these and a series of other related questions, while also drawing on the work of the Greek Marxist lawyer-philosopher Nicos Poulantzas to help elucidate some latent analytical stress-points in Kennedy’s broader theoretical framework. Reacting against the neo-Orientalist tone adopted across much of the contemporary field of Central Asian studies, it develops an alternative account of the internal history of the legal-globalizational encounter between the Western-based reform entrepreneurs and the national legal-political elites in Central Asia in the post-1991 period, complementing it with a detailed description of the general institutional and discursive structures within which this encounter took place

    Exosome loaded immunomodulatory biomaterials alleviate local immune response in immunocompetent diabetic mice post islet xenotransplantation

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    Foreign body response (FBR) to biomaterials compromises the function of implants and leads to medical complications. Here, we report a hybrid alginate microcapsule (AlgXO) that attenuated the immune response after implantation, through releasing exosomes derived from human Umbilical Cord Mesenchymal Stem Cells (XOs). Upon release, XOs suppress the local immune microenvironment, where xenotransplantation of rat islets encapsulated in AlgXO led to >170 days euglycemia in immunocompetent mouse model of Type 1 Diabetes. In vitro analyses revealed that XOs suppressed the proliferation of CD3/CD28 activated splenocytes and CD3+ T cells. Comparing suppressive potency of XOs in purified CD3+ T cells versus splenocytes, we found XOs more profoundly suppressed T cells in the splenocytes co-culture, where a heterogenous cell population is present. XOs also suppressed CD3/CD28 activated human peripheral blood mononuclear cells (PBMCs) and reduced their cytokine secretion including IL-2, IL-6, IL-12p70, IL-22, and TNFα. We further demonstrate that XOs mechanism of action is likely mediated via myeloid cells and XOs suppress both murine and human macrophages partly by interfering with NFκB pathway. We propose that through controlled release of XOs, AlgXO provide a promising new platform that could alleviate the local immune response to implantable biomaterials

    Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion σv\sigma_v and X-ray YXY_\textrm{X} Measurements

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    We present a velocity dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion (σv\sigma_v) and 16 X-ray Yx measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. The calibrations using σv\sigma_v and Yx are consistent at the 0.6σ0.6\sigma level, with the σv\sigma_v calibration preferring ~16% higher masses. We use the full cluster dataset to measure σ8(Ωm/0.27)0.3=0.809±0.036\sigma_8(\Omega_ m/0.27)^{0.3}=0.809\pm0.036. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming the sum of the neutrino masses is mν=0.06\sum m_\nu=0.06 eV, we find the datasets to be consistent at the 1.0σ\sigma level for WMAP9 and 1.5σ\sigma for Planck+WP. Allowing for larger mν\sum m_\nu further reconciles the results. When we combine the cluster and Planck+WP datasets with BAO and SNIa, the preferred cluster masses are 1.9σ1.9\sigma higher than the Yx calibration and 0.8σ0.8\sigma higher than the σv\sigma_v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness of fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe dataset, we measure Ωm=0.299±0.009\Omega_ m=0.299\pm0.009 and σ8=0.829±0.011\sigma_8=0.829\pm0.011. Within a ν\nuCDM model we find mν=0.148±0.081\sum m_\nu = 0.148\pm0.081 eV. We present a consistency test of the cosmic growth rate. Allowing both the growth index γ\gamma and the dark energy equation of state parameter ww to vary, we find γ=0.73±0.28\gamma=0.73\pm0.28 and w=1.007±0.065w=-1.007\pm0.065, demonstrating that the expansion and the growth histories are consistent with a LCDM model (γ=0.55;w=1\gamma=0.55; \,w=-1).Comment: Accepted by ApJ (v2 is accepted version); 17 pages, 6 figure

    Analysis of Sunyaev-Zel'dovich Effect Mass-Observable Relations using South Pole Telescope Observations of an X-ray Selected Sample of Low Mass Galaxy Clusters and Groups

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    (Abridged) We use 95, 150, and 220GHz observations from the SPT to examine the SZE signatures of a sample of 46 X-ray selected groups and clusters drawn from ~6 deg^2 of the XMM-BCS. These systems extend to redshift z=1.02, have characteristic masses ~3x lower than clusters detected directly in the SPT data and probe the SZE signal to the lowest X-ray luminosities (>10^42 erg s^-1) yet. We develop an analysis tool that combines the SZE information for the full ensemble of X-ray-selected clusters. Using X-ray luminosity as a mass proxy, we extract selection-bias corrected constraints on the SZE significance- and Y_500-mass relations. The SZE significance- mass relation is in good agreement with an extrapolation of the relation obtained from high mass clusters. However, the fit to the Y_500-mass relation at low masses, while in good agreement with the extrapolation from high mass SPT clusters, is in tension at 2.8 sigma with the constraints from the Planck sample. We examine the tension with the Planck relation, discussing sample differences and biases that could contribute. We also present an analysis of the radio galaxy point source population in this ensemble of X-ray selected systems. We find 18 of our systems have 843 MHz SUMSS sources within 2 arcmin of the X-ray centre, and three of these are also detected at significance >4 by SPT. Of these three, two are associated with the group brightest cluster galaxies, and the third is likely an unassociated quasar candidate. We examine the impact of these point sources on our SZE scaling relation analyses and find no evidence of biases. We also examine the impact of dusty galaxies using constraints from the 220 GHz data. The stacked sample provides 2.8σ\sigma significant evidence of dusty galaxy flux, which would correspond to an average underestimate of the SPT Y_500 signal that is (17+-9) per cent in this sample of low mass systems.Comment: 15 pages, 7 figure

    Probiotic-associated aspiration pneumonia due to Lactobacillus rhamnosus

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    Lactobacilli are low-virulence, commensal organisms of the gastrointestinal and genitourinary tracts and are commonly used as “probiotic supplements.” Herein, we describe an episode of respiratory syncytial virus (RSV) bronchiolitis with bacterial superinfection secondary to administration of Lactobacillus rhamnosus in an 11-month-old female with trisomy 21

    The Redshift Evolution of the Mean Temperature, Pressure, and Entropy Profiles in 80 SPT-Selected Galaxy Clusters

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    (Abridged) We present the results of an X-ray analysis of 80 galaxy clusters selected in the 2500 deg^2 South Pole Telescope survey and observed with the Chandra X-ray Observatory. We divide the full sample into subsamples of ~20 clusters based on redshift and central density, performing an X-ray fit to all clusters in a subsample simultaneously, assuming self-similarity of the temperature profile. This approach allows us to constrain the shape of the temperature profile over 0<r<1.5R500, which would be impossible on a per-cluster basis, since the observations of individual clusters have, on average, 2000 X-ray counts. The results presented here represent the first constraints on the evolution of the average temperature profile from z=0 to z=1.2. We find that high-z (0.6<z<1.2) clusters are slightly (~40%) cooler both in the inner (rR500) regions than their low-z (0.3<z<0.6) counterparts. Combining the average temperature profile with measured gas density profiles from our earlier work, we infer the average pressure and entropy profiles for each subsample. Overall, our observed pressure profiles agree well with earlier lower-redshift measurements, suggesting minimal redshift evolution in the pressure profile outside of the core. We find no measurable redshift evolution in the entropy profile at rR500 in our high-z subsample. This flattening is consistent with a temperature bias due to the enhanced (~3x) rate at which group-mass (~2 keV) halos, which would go undetected at our survey depth, are accreting onto the cluster at z~1. This work demonstrates a powerful method for inferring spatially-resolved cluster properties in the case where individual cluster signal-to-noise is low, but the number of observed clusters is high.Comment: 17 pages, 13 figures, submitted to ApJ. Updated following referee repor

    Constraints on the CMB Temperature Evolution using Multi-Band Measurements of the Sunyaev Zel'dovich Effect with the South Pole Telescope

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    The adiabatic evolution of the temperature of the cosmic microwave background (CMB) is a key prediction of standard cosmology. We study deviations from the expected adiabatic evolution of the CMB temperature of the form T(z)=T0(1+z)1αT(z) =T_0(1+z)^{1-\alpha} using measurements of the spectrum of the Sunyaev Zel'dovich Effect with the South Pole Telescope (SPT). We present a method for using the ratio of the Sunyaev Zel'dovich signal measured at 95 and 150 GHz in the SPT data to constrain the temperature of the CMB. We demonstrate that this approach provides unbiased results using mock observations of clusters from a new set of hydrodynamical simulations. We apply this method to a sample of 158 SPT-selected clusters, spanning the redshift range 0.05<z<1.350.05 < z < 1.35, and measure α=0.0170.028+0.030\alpha = 0.017^{+0.030}_{-0.028}, consistent with the standard model prediction of α=0\alpha=0. In combination with other published results, we constrain α=0.011±0.016\alpha = 0.011 \pm 0.016, an improvement of 20%\sim 20\% over published constraints. This measurement also provides a strong constraint on the effective equation of state in models of decaying dark energy weff=0.9870.017+0.016w_\mathrm{eff} = -0.987^{+0.016}_{-0.017}.Comment: Submitted to MNRAS Letter

    Cosmological Constraints from Galaxy Clusters in the 2500 square-degree SPT-SZ Survey

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    (abridged) We present cosmological constraints obtained from galaxy clusters identified by their Sunyaev-Zel'dovich effect signature in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich survey. We consider the 377 cluster candidates identified at z>0.25 with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a LCDM cosmology, where the species-summed neutrino mass has the minimum allowed value (mnu = 0.06 eV) from neutrino oscillation experiments, we combine the cluster data with a prior on H0 and find sigma_8 = 0.797+-0.031 and Omega_m = 0.289+-0.042, with the parameter combination sigma_8(Omega_m/0.27)^0.3 = 0.784+-0.039. These results are in good agreement with constraints from the CMB from SPT, WMAP, and Planck, as well as with constraints from other cluster datasets. Adding mnu as a free parameter, we find mnu = 0.14+-0.08 eV when combining the SPT cluster data with Planck CMB data and BAO data, consistent with the minimum allowed value. Finally, we consider a cosmology where mnu and N_eff are fixed to the LCDM values, but the dark energy equation of state parameter w is free. Using the SPT cluster data in combination with an H0 prior, we measure w = -1.28+-0.31, a constraint consistent with the LCDM cosmological model and derived from the combination of growth of structure and geometry. When combined with primarily geometrical constraints from Planck CMB, H0, BAO and SNe, adding the SPT cluster data improves the w constraint from the geometrical data alone by 14%, to w = -1.023+-0.042
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