1,879 research outputs found

    Correction to:Supply Chain Fragmentation and the Global Trade Elasticity: A New Accounting Framework (IMF Economic Review, (2021), 10.1057/s41308-021-00134-8)

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    The original version of this paper was inadvertently published with an incorrect affiliation for the author Robert Stehrer. The correct affiliation is: (1) The Vienna Institute for International Economic Studies – wiiw, Rahlgasse 3, A-1060 Vienna, Austria (2) The statement regarding the supplementary information was not given correctly and the supplementary material was not uploaded on SpringerLink. The original article has been corrected. We apologise for any inconvenience caused to our readers

    Supply Chain Fragmentation and the Global Trade Elasticity:A New Accounting Framework

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    In this paper, we offer a new framework to measure cross-border supply chain fragmentation and its impact on the global trade elasticity. Firstly, we introduce the supply chain fragmentation ratio that sums the volume of imports by all countries that participate in a particular supply chain. We find that supply chain fragmentation slowed down after 2010 for most goods, but not for services. We demonstrate the importance of using trade and production data at constant prices in measuring fragmentation trends. Secondly, we quantify the impact of fragmentation on the elasticity of trade to world GDP, extending the framework of Bems et al. (Am Econ Rev Pap Proc 101(3):308-312, 2011). We account for trade effects from fragmentation within supply chains as well as asymmetric shocks to final demand. We find that the declining pace of fragmentation accounted for more than a third of the decline in the global trade elasticity after 2010

    Slicing Up Global Value Chains

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    Pair conversion spectroscopy of the Hoyle state

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    The triple-alpha reaction leading to the formation of stable carbon in the Universe is one of the most important nuclear astrophysical processes. The radiative width of the so-called Hoyle state, involving the 7.654 MeV E0 and the 3.2148 MeV E2 transitio

    Statistical power in clinical trials of interventions for mood, anxiety, and psychotic disorders

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    BACKGROUND: Previous research has suggested that statistical power is suboptimal in many biomedical disciplines, but it is unclear whether power is better in trials for particular interventions, disorders, or outcome types. We therefore performed a detailed examination of power in trials of psychotherapy, pharmacotherapy, and complementary and alternative medicine (CAM) for mood, anxiety, and psychotic disorders.METHODS: We extracted data from the Cochrane Database of Systematic Reviews (Mental Health). We focused on continuous efficacy outcomes and estimated power to detect predetermined effect sizes (standardized mean difference [SMD] = 0.20-0.80, primary SMD = 0.40) and meta-analytic effect sizes (ESMA). We performed meta-regression to estimate the influence of including underpowered studies in meta-analyses.RESULTS: We included 256 reviews with 10 686 meta-analyses and 47 384 studies. Statistical power for continuous efficacy outcomes was very low across intervention and disorder types (overall median [IQR] power for SMD = 0.40: 0.32 [0.19-0.54]; for ESMA: 0.23 [0.09-0.58]), only reaching conventionally acceptable levels (80%) for SMD = 0.80. Median power to detect the ESMA was higher in treatment-as-usual (TAU)/waitlist-controlled (0.49-0.63) or placebo-controlled (0.12-0.38) trials than in trials comparing active treatments (0.07-0.13). Adequately-powered studies produced smaller effect sizes than underpowered studies (B = -0.06, p ⩽ 0.001).CONCLUSIONS: Power to detect both predetermined and meta-analytic effect sizes in psychiatric trials was low across all interventions and disorders examined. Consistent with the presence of reporting bias, underpowered studies produced larger effect sizes than adequately-powered studies. These results emphasize the need to increase sample sizes and to reduce reporting bias against studies reporting null results to improve the reliability of the published literature.</p

    A Systematic Review and Critical Appraisal of Peri-Procedural Tissue Perfusion Techniques and their Clinical Value in Patients with Peripheral Arterial Disease

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    Objective: Many techniques have been introduced to enable quantification of tissue perfusion in patients with peripheral arterial disease (PAD). Currently, none of these techniques is widely used to analyse real time tissue perfusion changes during endovascular or surgical revascularisation procedures. The aim of this systematic review was to provide an up to date overview of the peri-procedural applicability of currently available techniques, diagnostic accuracy of assessing tissue perfusion and the relationship with clinical outcomes. Data Sources: MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials. Review Methods: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) guidelines. Four electronic databases were searched up to 31 12 2020 for eligible articles: MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials. Eligible articles describing a perfusion measurement technique, used in a peri-procedural setting before and within 24 hours after the revascularisation procedure, with the aim of determining the effect of intervention in patients with PAD, were assessed for inclusion. The QUADAS-2 tool was used to assess the risk of bias and applicability of the studies. Results: An overview of 10 techniques found in 26 eligible articles focused on study protocols, research goals, and clinical outcomes is provided. Non-invasive techniques included laser speckle contrast imaging, micro-lightguide spectrophotometry, magnetic resonance imaging perfusion, near infrared spectroscopy, skin perfusion pressure, and plantar thermography. Invasive techniques included two dimensional perfusion angiography, contrast enhanced ultrasound, computed tomography perfusion imaging, and indocyanine green angiography. The results of the 26 eligible studies, which were mostly of poor quality according to QUADAS-2, were without exception, not sufficient to substantiate implementation in daily clinical practice. Conclusion: This systematic review provides an overview of 10 tissue perfusion assessment techniques for patients with PAD. It seems too early to appoint one of them as a reference standard. The scope of future research in this domain should therefore focus on clinical accuracy, reliability, and validation of the techniques

    Can transplant renal scintigraphy predict the duration of delayed graft function? A dual center retrospective study:A dual center retrospective study

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    Introduction: This study focused on the value of quantitatively analyzed and qualitatively graded renal scintigraphy in relation to the expected duration of delayed graft function after kidney transplantation. A more reliable prediction of delayed graft function duration may result in a more tailored and patient-specific treatment regimen post-transplantation. Methods: From 2000 to 2014, patients with early transplant dysfunction and a Tc-99m MAG3 renal scintigraphy, within 3 days post-transplantation, were included in a dual center retrospective study. Time-activity curves of renal scintigraphy procedures were qualitatively graded and various quantitative indices (R20/3, TFS, cTER, MUC10) were combined with a new index (Average upslope). The delayed graft function duration was defined as the number of days of dialysis-based/functional delayed graft function. Results: A total of 377 patients were included, with a mean age (± SD) of 52 ± 14 years, and 58% were male. A total of 274 (73%) patients experienced delayed graft function 7 days. Qualitative grading for the prediction of delayed graft function 7 days had a sensitivity and specificity of respectively 87% and 65%. The quantitative indices with the most optimal results were cTER (76% sensitivity, 72% specificity), and Average upslope (75% sensitivity, 73% specificity). Conclusions: Qualitative renal scintigraphy grading and the quantitative indices cTER and Average upslope predict delayed graft function ≥7 days with a high sensitivity. This finding may help to support both clinicians and patients in managing early post-operative expectations. However, the specificity is limited and thus renal scintigraphy does not reliably help to identify patients in whom the course of delayed graft function is longer than anticipated

    Hierarchical Multivalent Effects Control Influenza Host Specificity

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    Understanding how emerging influenza viruses recognize host cells is critical in evaluating their zoonotic potential, pathogenicity, and transmissibility between humans. The surface of the influenza virus is covered with hemagglutinin (HA) proteins that can form multiple interactions with sialic acid-terminated glycans on the host cell surface. This multivalent binding affects the selectivity of the virus in ways that cannot be predicted from the individual receptor-ligand interactions alone. Here, we show that the intrinsic structural and energetic differences between the interactions of avian- or human-type receptors with influenza HA translate from individual site affinity and orientation through receptor length and density on the surface into virus avidity and specificity. We introduce a method to measure virus avidity using receptor density gradients. We found that influenza viruses attached stably to a surface at receptor densities that correspond to a minimum number of approximately 8 HA-glycan interactions, but more interactions were required if the receptors were short and human-type. Thus, the avidity and specificity of influenza viruses for a host cell depend not on the sialic acid linkage alone but on a combination of linkage and the length and density of receptors on the cell surface. Our findings suggest that threshold receptor densities play a key role in virus tropism, which is a predicting factor for both their virulence and zoonotic potential.Fil: Overeem, Nico J.. University of Twente; Países BajosFil: Hamming, P. H. Erik. University of Twente; Países BajosFil: Grant, Oliver C.. University of Georgia; Estados UnidosFil: Di Iorio, Daniele. University of Twente; Países BajosFil: Tieke, Malte. Utrecht University; Países BajosFil: Bertolino, María Candelaria. University of Twente; Países Bajos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Li, Zeshi. Utrecht University; Países BajosFil: Vos, Gaël. Utrecht University; Países BajosFil: de Vries, Robert P.. Utrecht University; Países BajosFil: Woods, Robert J.. University of Georgia; Estados UnidosFil: Tito, Nicholas B.. Electric Ant Laboratory; Países BajosFil: Boons, Geert-Jan P. H.. Utrecht University; Países BajosFil: van der Vries, Erhard. Utrecht University; Países BajosFil: Huskens, Jurriaan. University of Twente; Países Bajo
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