Due to the rise of global supply chains, gross exports do not accurately measure the amount of value added exchanged between countries. I highlight five facts about differences between gross and ...value-added exports. These differences are large and growing over time, currently around 25 percent, and manufacturing trade looks more important, relative to services, in gross than value-added terms. These differences are also heterogenous across countries and bilateral partners, and changing unevenly across countries and partners over time. Taking these differences into account enables researchers to obtain better quantitative answers to important macroeconomic and trade questions. I discuss how the facts inform analysis of the transmission of shocks across countries; the mechanics of trade balance adjustments; the impact of frictions on trade; the role of endowments and comparative advantage; and trade policy.
C−H Functionalization of Commodity Polymers Williamson, Jill B.; Lewis, Sally E.; Johnson, Robert R. ...
Angewandte Chemie,
June 24, 2019, Letnik:
58, Številka:
26
Journal Article
Recenzirano
Odprti dostop
Synthetic manipulation of polymer substrates is one of the oldest and most reliable methods to increase the functional diversity of soft materials. Modifying the chemical structure of polymers that ...are already produced on a commodity scale leverages the current high‐volume and low‐cost production of commodity plastics for the discovery of modern materials. A myriad of polymer C−H functionalization methods have been developed which enable the modification of material properties on both a laboratory and industrial scale. More recently, driven by advances in C−H activation, photoredox catalysis, and radical chemistry, chemoselective approaches have emerged as a means to impart precise functionality onto commodity polymer substrates. This Review discusses the historical significance of and contemporary advances in the C−H functionalization of commodity polymers. The conceptual approach outlined herein presents exciting new directions for the field, including increasing the value of otherwise pervasive materials, uncovering entirely new material properties, and a viable path to upcycle post‐consumer plastic waste.
Hot commodities: This Review discusses the historical significance of and contemporary advances in the C−H functionalization of commodity polymers. Exciting new directions for the field are presented, including uncovering new material properties and upcycling post‐consumer plastic waste.
We combine data on trade, production, and input use to document changes in the value-added content of trade between 1970 and 2009. The ratio of value-added to gross exports fell by roughly 10 ...percentage points worldwide. The ratio declined 20 percentage points in manufacturing, but rose in nonmanufacturing sectors. Declines also differ across countries and trade partners: they are larger for fast-growing countries, for nearby trade partners, and among partners that adopt regional trade agreements. Using a multisector structural gravity model with input-output linkages, we show that changes in trade frictions play a dominant role in explaining all these facts.
Measuring Global Value Chains Johnson, Robert C
Annual review of economics,
01/2018, Letnik:
10, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Recent decades have seen the emergence of global value chains (GVCs), in which production stages for individual goods are broken apart and scattered across countries. Stimulated by these ...developments, there has been rapid progress in data and methods for measuring GVC linkages. The macro approach to measuring GVCs connects national input-output tables across borders by using bilateral trade data to construct global input-output tables. These tables have been applied to measure trade in value added, the length of and location of producers in GVCs, and price linkages across countries. The micro approach uses firm-level data to document firms' input sourcing decisions, how import and export participation are linked, and how multinational firms organize their production networks. In this review, I evaluate progress in these two approaches, highlighting points of contact between them and areas that demand further work. I argue that further convergence between these approaches can strengthen both, yielding a more complete empirical portrait of GVCs.
We combine input–output and bilateral trade data to compute the value added content of bilateral trade. The ratio of value added to gross exports (VAX ratio) is a measure of the intensity of ...production sharing. Across countries, export composition drives VAX ratios, with exporters of Manufactures having lower ratios. Across sectors, the VAX ratio for Manufactures is low relative to Services, primarily because Services are used as an intermediate to produce manufacturing exports. Across bilateral partners, VAX ratios vary widely and contain information on both bilateral and triangular production chains. We document specifically that bilateral production linkages, not variation in the composition of exports, drive variation in bilateral VAX ratios. Finally, bilateral imbalances measured in value added differ from gross trade imbalances. Most prominently, the U.S.–China imbalance in 2004 is 30–40% smaller when measured in value added.
► We estimate the value added content of trade using a global input–output framework. ► The aggregate value added to export ratio for the median country is roughly 70%. ► Bilateral ratios vary due to production sharing patterns, not export composition. ► Bilateral value added trade imbalances differ from gross trade imbalances. ► The U.S.–China value added imbalance is 30–40% smaller than the gross imbalance.
The heart is a complex organ composed of multiple cell types, including cardiomyocytes and different non-myocyte populations, all working closely together to determine the hearts properties and ...maintain normal cardiac function. Connexins are abundantly expressed proteins that form plasma membrane hemichannels and gap junctions between cells. Gap junctions are intracellular channels that allow for communication between cells, and in the heart they play a crucial role in cardiac conduction by coupling adjacent cardiomyocytes. Connexins are expressed in both cardiomyocytes and non-myocytes, including cardiac fibroblasts, endothelial cells, and macrophages. Non-myocytes are the largest population of cells in the heart, and therefore it is important to consider what roles connexins, hemichannels, and gap junctions play in these cell types. The aim of this review is to provide insight into connexin-based signalling in non-myocytes during health and disease, and highlight how targeting these proteins could lead to the development of novel therapies. We conclude that connexins in non-myocytes contribute to arrhythmias and adverse ventricular remodelling following myocardial infarction, and are associated with the initiation and development of atherosclerosis. Therefore, therapeutic interventions targeting these connexins represent an exciting new research avenue with great potential.
Genetic studies with S. cerevisiae Polδ (pol3-L612M) and Polε (pol2-M644G) mutant alleles, each of which display a higher rate for the generation of a specific mismatch, have led to the conclusion ...that Polε is the primary leading strand replicase and that Polδ is restricted to replicating the lagging strand template. Contrary to this widely accepted view, here we show that Polδ plays a major role in the replication of both DNA strands, and that the paucity of pol3-L612M-generated errors on the leading strand results from their more proficient removal. Thus, the apparent lack of Polδ contribution to leading strand replication is due to differential mismatch removal rather than differential mismatch generation. Altogether, our genetic studies with Pol3 and Pol2 mutator alleles support the conclusion that Polδ, and not Polε, is the major DNA polymerase for carrying out both leading and lagging DNA synthesis.
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•Polδ-generated errors occur on both the leading and lagging DNA strands•Polδ errors are removed by mismatch repair, Polε exonuclease, and Exo1•Polδ replicates both the leading and lagging DNA strands•Polε does not replicate the leading strand
The current model of eukaryotic DNA replication suggests that DNA polymerase (Pol)ε primarily replicates the leading strand while Polδ replicates the lagging strand. Johnson et al. provide genetic evidence that Polδ replicates both strands, while Polε’s proofreading activity is important for removing Polδ-generated errors from the leading strand.
Six decades after its conception, proton computed tomography (pCT) and proton radiography have yet to be used in medical clinics. However, good progress has been made on relevant detector ...technologies in the past two decades, and a few prototype pCT systems now exist that approach the performance needed for a clinical device. The tracking and energy-measurement technologies in common use are described, as are the few pCT scanners that are in routine operation at this time. Most of these devices still look like detector R&D efforts as opposed to medical devices, are difficult to use, are at least a factor of five slower than desired for clinical use, and are too small to image many parts of the human body. Recommendations are made for what to consider when engineering a pre-clinical pCT scanner that is designed to meet clinical needs in terms of performance, cost, and ease of use.
Introduction
War in Ukraine started in March 2014 when Russia annexed Crimea and continues today in the Donbass region of Eastern Ukraine. Over 1.5 million people in these regions have been displaced ...from their homes. We conducted this study 36 months after the conflict began and interviewed civilians residing in Ukraine.
Purpose
This study examines the prevalence of exposure to war trauma, rates of PTSD by symptom clusters, and whether socio-demographic factors are associated with positive scores for PTSD among civilian urban-dwelling and internally displaced persons in Ukraine during the ongoing conflict in its Donbass region.
Methods
Face-to-face interviews were conducted using a multi-stage random sample of the general population in two large cities (Kharkiv and Lviv) in Ukraine (
n
= 1247) and a purposive sample of internally displaced persons (
n
= 300), half living in each city. Exposure to trauma, symptom clusters for Posttraumatic Stress Disorder (PTSD), and overall PTSD were assessed.
Results
We found widespread direct exposure to conflict-related traumatic events (65%) among internally displaced people (IDPs) compared to a sizable minority (23%) of urban-dwelling people (UDPs). We found elevated prevalence of PTSD symptoms that were also uniformly spread within several socio-demographic factors. There were, however, significant differences in PTSD between (1) IDPs compared to UDPs and (2) those UDPs with Ukrainian compared to Russian ethnic identity, the former of each pair showing increased likelihoods of positive PTSD scores.
Conclusions
Ukraine’s adult civilians, enduring the prolonged engagement in war with Russia and Russian separatists, have elevated rates of PTSD. Moreover, those who have been displaced by the ongoing conflict (IDPs) have significantly higher levels of PTSD compared to UDPs.
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