This paper studies how reduction in trade policy uncertainty affects firm export decisions. Using a firm–product level dataset on Chinese exports to the United States and the European Union in the ...years surrounding China's WTO accession, we provide strong evidence that reduction in trade policy uncertainty simultaneously induced firm entries to and firm exits from export activity within fine product-level markets. In addition, we uncover accompanying changes in export product prices and quality that coincided with this reallocation: firms that provided higher quality products at lower prices entered the export market, while firms that had higher prices and provided lower quality products prior to the changes, exited. To explain the simultaneous export entries and exits, as well as the fact that new entrants are more productive than exiters, we provide a model of heterogeneous firms which incorporates trade policy uncertainty, tracing the effects of the changes in policy uncertainty on firm-level payoffs and the resulting selection effects.
We use Chinese manufacturing firm data to estimate the causal effect of increased imported intermediate input use on firm export outcomes. To account for the endogeneity of import decisions, we ...pursue an IV strategy that utilizes instruments for import costs connected to intermediate input import tariffs, exchange rates, and firm differences in fixed trade costs. We find that firms that expanded their intermediate input imports expanded the volume and scope of their exports. Further, we find that the benefit of imported inputs differed along a number of dimensions including initial trade status, import source country, export destination, firm ownership, and industry R&D intensity. Although increased imports of intermediates boosted exports by all firms, we find that the effects were largest when they were purchased by private firms or firms that started out as non-traders. In addition, intermediate inputs from the higher-income G7 countries were especially helpful in facilitating firm exports to the presumably more-demanding G7 export markets. Taken together, these results suggest that product upgrading facilitated by technology or quality embedded in imported inputs helped Chinese firms to increase the scale and breadth of their participation in export markets.
Metagenomic sequencing provides a window into microbial community structure and metabolic potential; however, linking these data to exogenous metabolites that microorganisms process and produce (the ...exometabolome) remains challenging. Previously, we observed strong exometabolite niche partitioning among bacterial isolates from biological soil crust (biocrust). Here we examine native biocrust to determine if these patterns are reproduced in the environment. Overall, most soil metabolites display the expected relationship (positive or negative correlation) with four dominant bacteria following a wetting event and across biocrust developmental stages. For metabolites that were previously found to be consumed by an isolate, 70% are negatively correlated with the abundance of the isolate's closest matching environmental relative in situ, whereas for released metabolites, 67% were positively correlated. Our results demonstrate that metabolite profiling, shotgun sequencing and exometabolomics may be successfully integrated to functionally link microbial community structure with environmental chemistry in biocrust.
Abstract
A recent hypothesis holds that changes to the East Asian summer rainfall are characterized by changes in the timing and duration of its intraseasonal stages, controlled by the meridional ...position of the westerlies relative to the Tibetan Plateau. This hypothesis is examined in the context of the leading mode of East Asian summer (July–August) rainfall. One phase of this “tripole” mode—characterized by less rainfall over central eastern China and increased rainfall over northeastern and southeastern China—is tied to an earlier termination of Meiyu that results in a significantly shorter Meiyu and longer Midsummer stage. This phase also exhibits an earlier northward transition of the westerlies to the north of the Plateau, essentially mirroring the changes to precipitation seasonality. The reverse does not hold true for the opposite phase. Our results show direct observational evidence for the meridional position of the westerlies to control East Asian summer monsoon seasonality.
Key Points
Leading mode of July‐August East Asian rainfall variability caused by changes in timing of Meiyu termination and duration of Meiyu/Midsummer
Changes to timing and duration associated with variation in the meridional migration of westerlies relative to the Tibetan Plateau
Results show direct observational evidence for meridional position of westerlies to control East Asian summer monsoon seasonality
Understanding magnetic phases in quantum mechanical systems is one of the essential goals in condensed matter physics, and the advent of prototype quantum simulation hardware has provided new tools ...for experimentally probing such systems. We report on the experimental realization of a quantum simulation of interacting Ising spins on three-dimensional cubic lattices up to dimensions 8 × 8 × 8 on a D-Wave processor (D-Wave Systems, Burnaby, Canada). The ability to control and read out the state of individual spins provides direct access to several order parameters, which we used to determine the lattice's magnetic phases as well as critical disorder and one of its universal exponents. By tuning the degree of disorder and effective transverse magnetic field, we observed phase transitions between a paramagnetic, an antiferromagnetic, and a spin-glass phase.
Integrating multiomics datasets is critical for microbiome research; however, inferring interactions across omics datasets has multiple statistical challenges. We solve this problem by using neural ...networks (https://github.com/biocore/mmvec) to estimate the conditional probability that each molecule is present given the presence of a specific microorganism. We show with known environmental (desert soil biocrust wetting) and clinical (cystic fibrosis lung) examples, our ability to recover microbe-metabolite relationships, and demonstrate how the method can discover relationships between microbially produced metabolites and inflammatory bowel disease.
Background. Currently, there are no licensed vaccines or therapeutics for the prevention or treatment of infection by the highly lethal filoviruses, Ebola virus (EBOV) and Marburg virus (MARV), in ...humans.We previously had demonstrated the protective efficacy of virus-like particle (VLP)-based vaccines against EBOV and MARV infection in rodents. Methods. To determine the efficacy of vaccination with Ebola VLPs (eVLPs) in nonhuman primates, we vaccinated cynomolgus macaques with eVLPs containing EBOV glycoprotein (GP), nucleoprotein (NP), and VP40 matrix protein and challenged the macaques with 1000 pfu of EBOV. Results. Serum samples from the eVLP-vaccinated nonhuman primates demonstrated EBOV-specific antibody titers, as measured by enzyme-linked immunosorbent assay, complement-mediated lysis assay, and anti-body dependent cell-mediated cytotoxicity assay. CD44+ T cells from eVLP-vaccinated macaques but not from a naive macaque responded with vigorous production of tumor necrosis factor-α after EBOV-peptide stimulation. All 5 eVLP-vaccinated monkeys survived challenge without clinical or laboratory signs of EBOV infection, whereas the control animal died of infection. Conclusion. On the basis of safety and efficacy, eVLPs represent a promising filovirus vaccine for use in humans.
A current aperture vertical electron transistor (CAVET) with a Mg-ion-implanted current blocking layer (CBL) and a channel regrown by plasma assisted molecular beam epitaxy (MBE), is successfully ...demonstrated on bulk GaN to work as a high voltage device. The fabrication of the device combined a drift region grown by metalorganic chemical vapor deposition (MOCVD), to hold the blocking voltage, with AlGaN/GaN layers regrown by plasma-MBE to conduct current. The device registered a maximum current of 4 kA· cm -2 under direct-current operation offering a specific on-state resistance R on - A of 2.2 mΩ·cm 2 . With 80 μs pulses applied to the gate, the devices showed no dispersion. The increased aperture length L ap resulted in the decrease in specific R on , as expected. The impact of the gate overlap to aperture L go on the leakage current was studied, where the leakage current was found to increase with a smaller overlap.
The molecular composition of soil organic matter (SOM) sets the foundation for terrestrial microbial community structures and carbon cycling dynamics. However, the specific chemical constituents of ...SOM are underexplored. In this chapter we present a protocol for the extraction of small molecule metabolites from soil followed by compound detection and identification using liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. There are options within the protocol to assess either the extracellular pool of metabolites or the total pool (including intracellular) and either polar or nonpolar metabolites, depending on the reader's research interests. These methods can be followed individually for a more targeted analysis or all methods can be combined to obtain a more comprehensive understanding of SOM metabolite composition (such as amino acids, nucleobases, organic acids, fatty acids, carbohydrates, secondary metabolites, and antibiotics).
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