110 research outputs found

    Services trade, regulation, and regional integration: Evidence from sectoral data

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    Regulatory measures constitute a significant barrier to cross-border services trade in sectors including transport, communications, business services, insurance, and recreation. However, regulation has weaker effects on trade in financial services, distribution, and construction. Entry barriers and conduct regulations have heterogeneous effects across sectors, as do particular measures such as licensing requirements, economic needs tests, restrictions on business form, and limitations on advertising. In addition, regional trade agreements (RTAs) are trade creating in communications, finance, and distribution, but have only weak effects in other sectors. Contrary to findings for goods markets, trade diversion is relatively limited for services RTAs.Trade in services; Non-tariff measures; Regional integration

    Services trade, regulation, and regional integration: Evidence from sectoral data

    Get PDF
    Regulatory measures constitute a significant barrier to cross-border services trade in sectors including transport, communications, business services, insurance, and recreation. However, regulation has weaker effects on trade in financial services, distribution, and construction. Entry barriers and conduct regulations have heterogeneous effects across sectors, as do particular measures such as licensing requirements, economic needs tests, restrictions on business form, and limitations on advertising. In addition, regional trade agreements (RTAs) are trade creating in communications, finance, and distribution, but have only weak effects in other sectors. Contrary to findings for goods markets, trade diversion is relatively limited for services RTAs

    Digital trade, data protection and EU adequacy decisions

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    Using a structural gravity model, we assess whether EU adequacy decisions on data protection are associated with bilateral digital trade. Controlling for digital-relevant bilateral covariates, including preferential trade agreements and other binding data flow arrangements, we find that countries that received EU adequacy exhibit an increase in digital trade between 6-14 percent, representing a trade cost reduction up to 9 percent. This is mostly driven by the EU granting adequacy to the U.S., reflecting the dominance of the EU and U.S. in global digital trade. We also find that countries that have an EU adequacy determination exhibit greater digital trade among each other, suggestive of a network or club effect. Complementary country-specific analysis of post-adequacy digital trade performance using synthetic control methods confirms the positive effects of adequacy.This work was partially supported by the ESRC Centre of Inclusive Trade Policy, UK (Hoekman

    Supernova Remnants and Star Formation in the Large Magellanic Cloud

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    It has often been suggested that supernova remnants (SNRs) can trigger star formation. To investigate the relationship between SNRs and star formation, we have examined the known sample of 45 SNRs in the Large Magellanic Cloud to search for associated young stellar objects (YSOs) and molecular clouds. We find seven SNRs associated with both YSOs and molecular clouds, three SNRs associated with YSOs but not molecular clouds, and eight SNRs near molecular clouds but not associated with YSOs. Among the 10 SNRs associated with YSOs, the association between the YSOs and SNRs can be either rejected or cannot be convincingly established for eight cases. Only two SNRs have YSOs closely aligned along their rims; however, the time elapsed since the SNR began to interact with the YSOs' natal clouds is much shorter than the contraction timescales of the YSOs, and thus we do not see any evidence of SNR-triggered star formation in the LMC. The 15 SNRs that are near molecular clouds may trigger star formation in the future when the SNR shocks have slowed down to <45 km/s. We discuss how SNRs can alter the physical properties and abundances of YSOs.Comment: 24 pages, 5 figures, 1 table, Accepted for publication in the August 2010 edition of the Astronomical Journa

    Star Formation Histories of Ultra-faint Dwarf Galaxies: Environmental Differences between Magellanic and Non-Magellanic Satellites?*

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    We present the color–magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix 2, Reticulum 2, Sagittarius 2, Triangulum 2, and Tucana 2, derived from highprecision Hubble Space Telescope photometry. We find that the SFH of each galaxy is consistent with them having created at least 80% of the stellar mass by z ∼ 6. For all galaxies, we find quenching times older than 11.5 Gyr ago, compatible with the scenario in which reionization suppresses the star formation of small dark matter halos. However, our analysis also reveals some differences in the SFHs of candidate Magellanic Cloud satellites, i.e., galaxies that are likely satellites of the Large Magellanic Cloud and that entered the Milky Way potential only recently. Indeed, Magellanic satellites show quenching times about 600 Myr more recent with respect to those of other Milky Way satellites, on average, even though the respective timings are still compatible within the errors. This finding is consistent with theoretical models that suggest that satellites’ SFHs may depend on their host environment at early times, although we caution that within the error bars all galaxies in our sample are consistent with being quenched at a single epoch

    M31 satellite masses compared to CDM subhaloes

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    We have selected the positions of 54 6.7 GHz methanol masers from the Methanol Multibeam Survey catalogue, covering a range of longitudes between 20◦ and 34◦ of the Galactic plane. These positions were mapped in the J = 3−2 transition of both the 13CO and C18O lines. A total of 58 13CO emission peaks are found in the vicinity of these maser positions. We search for outflows around all 13CO peaks, and find evidence for high-velocity gas in all cases, spatially resolving the red and blue outflow lobes in 55 cases. Of these sources, 44 have resolved kinematic distances, and are closely associated with the 6.7 GHz masers, a subset referred to as Methanol Maser Associated Outflows (MMAOs). We calculate the masses of the clumps associated with each peak using 870 µm continuum emission from the ATLASGAL survey. A strong correlation is seen between the clump mass and both outflow mass and mechanical force, lending support to models in which accretion is strongly linked to outflow. We find that the scaling law between outflow activity and clump masses observed for low-mass objects, is also followed by the MMAOs in this study, indicating a commonality in the formation processes of low-mass and high-mass stars

    Functional MRI and Diffusion Tensor Imaging of Brain Reorganization After Experimental Stroke

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    The potential of the adult brain to reorganize after ischemic injury is critical for functional recovery and provides a significant target for therapeutic strategies to promote brain repair. Despite the accumulating evidence of brain plasticity, the interaction and significance of morphological and physiological modifications in post-stroke brain tissue remain mostly unclear. Neuroimaging techniques such as functional MRI (fMRI) and diffusion tensor imaging (DTI) enable in vivo assessment of the spatial and temporal pattern of functional and structural changes inside and outside ischemic lesion areas. This can contribute to the elucidation of critical aspects in post-stroke brain remodeling. Task/stimulus-related fMRI, resting-state fMRI, or pharmacological MRI enables direct or indirect measurement of neuronal activation, functional connectivity, or neurotransmitter system responses, respectively. DTI allows estimation of the structural integrity and connectivity of white matter tracts. Together, these MRI methods provide an unprecedented means to (a) measure longitudinal changes in tissue structure and function close by and remote from ischemic lesion areas, (b) evaluate the organizational profile of neural networks after stroke, and (c) identify degenerative and restorative processes that affect post-stroke functional outcome. Besides, the availability of MRI in clinical institutions as well as research laboratories provides an optimal basis for translational research on stroke recovery. This review gives an overview of the current status and perspectives of fMRI and DTI applications to study brain reorganization in experimental stroke models

    The Hubble Space Telescope Survey of M31 Satellite Galaxies. II. The Star Formation Histories of Ultrafaint Dwarf Galaxies

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    We present the lifetime star formation histories (SFHs) for six ultrafaint dwarf (UFD; M V > − 7.0, 4.9<log10(M*(z=0)/M⊙)<5.5 ) satellite galaxies of M31 based on deep color–magnitude diagrams constructed from Hubble Space Telescope imaging. These are the first SFHs obtained from the oldest main-sequence turnoff of UFDs outside the halo of the Milky Way (MW). We find that five UFDs formed at least 50% of their stellar mass by z = 5 (12.6 Gyr ago), similar to known UFDs around the MW, but that 10%–40% of their stellar mass formed at later times. We uncover one remarkable UFD, And xiii, which formed only 10% of its stellar mass by z = 5, and 75% in a rapid burst at z ∼ 2–3, a result that is robust to choices of underlying stellar model and is consistent with its predominantly red horizontal branch. This “young” UFD is the first of its kind and indicates that not all UFDs are necessarily quenched by reionization, which is consistent with predictions from several cosmological simulations of faint dwarf galaxies. SFHs of the combined MW and M31 samples suggest reionization did not homogeneously quench UFDs. We find that the least-massive MW UFDs (M *(z = 5) ≲ 5 × 104 M ⊙) are likely quenched by reionization, whereas more-massive M31 UFDs (M *(z = 5) ≳ 105 M ⊙) may only have their star formation suppressed by reionization and quench at a later time. We discuss these findings in the context of the evolution and quenching of UFDs
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