151 research outputs found

    Economic Policy Uncertainty and Bank Valuations

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    This paper examines the relation between economic policy uncertainty and bank valuation.  We use financial data and stock data of U.S bank holding companies over the period of 2002-2015. We use Tobin’s Q as the dependent variable and economic policy uncertainty (EPU) index asindependent variable. We find that the results differ across banks of different size and over different time period. Before and after the financial crisis, a negative relationship is roughly held. However, during the crisis, the results are mixed. Notably, for small banks, the impacts from monetary policy and overall economic policy uncertainty become insignificant. For large and medium banks, the monetary policy uncertainty becomes positively related to bank valuation. And probably because of the cancel-out effect, the overall economic policy uncertainty turns out to be non-negatively associated with bank valuation. We think the results may be explained by “too big to fail” and “constant probability of disaster” theories

    Effects of Coronal Magnetic Field Configuration on Particle Acceleration and Release during the Ground Level Enhancement Events in Solar Cycle 24

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    Ground level enhancements (GLEs) are extreme solar energetic particle (SEP) events that are of particular importance in space weather. In solar cycle 24, two GLEs were recorded on 2012 May 17 (GLE 71) and 2017 September 10 (GLE 72), respectively, by a range of advanced modern instruments. Here we conduct a comparative analysis of the two events by focusing on the effects of large-scale magnetic field configuration near active regions on particle acceleration and release. Although the active regions both located near the western limb, temporal variations of SEP intensities and energy spectra measured in-situ display different behaviors at early stages. By combining a potential field model, we find the CME in GLE 71 originated below the streamer belt, while in GLE 72 near the edge of the streamer belt. We reconstruct the CME shock fronts with an ellipsoid model based on nearly simultaneous coronagraph images from multi-viewpoints, and further derive the 3D shock geometry at the GLE onset. The highest-energy particles are primarily accelerated in the shock-streamer interaction regions, i.e., likely at the nose of the shock in GLE 71 and the eastern flank in GLE 72, due to quasi-perpendicular shock geometry and confinement of closed fields. Subsequently, they are released to the field lines connecting to near-Earth spacecraft when the shocks move through the streamer cusp region. This suggests that magnetic structures in the corona, especially shock-streamer interactions, may have played an important role in the acceleration and release of the highest-energy particles in the two events.Comment: Accepted for publication in Ap

    Composite Edible Film Containing Microcapsules Composed of Shrimp-derived Bioactive Peptide Preparation and Preservation Potential

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    Shrimp body had to face with spoilage and melanosis when it come to food preservation. In this study, a kind of composite edible film (CEF) composed of hydroxypropyl methyl cellulose (HPMC) and shrimp-derived bioactive peptide microcapsule (SBPM), was developed to preserve the body of Penaeus vannamei. First of all, single-factor experiments were conducted by monitoring the mechanical performance and the water vapor permeability (WVP) of CEF, in order to investigate the influence of the dosages of HPMC, glycerol and SBPM, upon the formulation properties and mechanical strength of the film. The FTIR and free radical scavenging capacity of CEF were also determined when the SBPM addition changed and then, the optimum preparation process of CEF was ascertained based on the results mentioned above. In addition, the preservation-effect of CEF on fresh Penaeus vannamei was evaluated by inspecting some important items such as the sensory evaluation, pH, total volatile basic nitrogen (TVB-N) and aerobic bacterial count of shrimp flesh. The results of the single-factor experiments indicated the optimum amounts of HPMC, glycerol and SBPM were 12%, 0.4% and 3%, respectively, and the comprehensive performance of CEF was satisfied under this optimum condition. The antioxidant ability of CEF was excellent when the dosage of SBPM was not less than 3% and, the interaction between SBPM and other membrane fractions was powerful when the addition amount of SBPM came to be 3%~4%, which was indicated by the FTIR results. More importantly, the spoilage of shrimp body could be controlled by covering the body with CEF and, the sensory of seafood might be maintained by this film, as evidenced by the inhibitory effects of CEF on the raising of body pH, the jump of TVB-N and the increase of aerobic bacterial count in shrimp fresh. The quality guarantee period of fresh body in CEF group could be prolonged by 3~4 days as compared with that in unprotected group, while the overall freshness-keeping ablility of CEF was superior to that of HPMC film even PE film, indicating the potent protective effect of CEF on the fresh of Penaeus vannamei

    Rapid and Unconditional Parametric Reset Protocol for Tunable Superconducting Qubits

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    Qubit initialization is a critical task in quantum computation and communication. Extensive efforts have been made to achieve this with high speed, efficiency and scalability. However, previous approaches have either been measurement-based and required fast feedback, suffered from crosstalk or required sophisticated calibration. Here, we report a fast and high-fidelity reset scheme, avoiding the issues above without any additional chip architecture. By modulating the flux through a transmon qubit, we realize a swap between the qubit and its readout resonator that suppresses the excited state population to 0.08% ±\pm 0.08% within 34 ns (284 ns if photon depletion of the resonator is required). Furthermore, our approach (i) can achieve effective second excited state depletion, (ii) has negligible effects on neighbouring qubits, and (iii) offers a way to entangle the qubit with an itinerant single photon, useful in quantum communication applications.Comment: 38 pages, 15 figure

    A Novel Postbiotic From Lactobacillus rhamnosus GG With a Beneficial Effect on Intestinal Barrier Function

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    It has long been known that probiotics can be used to maintain intestinal homeostasis and treat a number of gastrointestinal disorders, but the underlying mechanism has remained obscure. Recently, increasing evidence supports the notion that certain probiotic-derived components, such as bacteriocins, lipoteichoic acids, surface layer protein and secreted protein, have a similar protective role on intestinal barrier function as that of live probiotics. These bioactive components have been named ‘postbiotics’ in the most recent publications. We previously found that the Lactobacillus rhamnosus GG (LGG) culture supernatant is able to accelerate the maturation of neonatal intestinal defense and prevent neonatal rats from oral Escherichia coli K1 infection. However, the identity of the bioactive constituents has not yet been determined. In this study, using liquid chromatography-tandem mass spectrometry analysis, we identified a novel secreted protein (named HM0539 here) involved in the beneficial effect of LGG culture supernatant. HM0539 was recombinated, purified, and applied for exploring its potential bioactivity in vitro and in vivo. Our results showed that HM0539 exhibits a potent protective effect on the intestinal barrier, as reflected by enhancing intestinal mucin expression and preventing against lipopolysaccharide (LPS)- or tumor necrosis factor α (TNF-α)-induced intestinal barrier injury, including downregulation of intestinal mucin (MUC2), zonula occludens-1 (ZO-1) and disruption of the intestinal integrity. Using a neonatal rat model of E. coli K1 infection via the oral route, we verified that HM0539 is sufficient to promote development of neonatal intestinal defense and prevent against E. coli K1 pathogenesis. Moreover, we further extended the role of HM0539 and found it has potential to prevent dextran sulfate sodium (DSS)-induced colitis as well as LPS/D-galactosamine-induced bacterial translocation and liver injury. In conclusion, we identified a novel LGG postbiotic HM0539 which exerts a protective effect on intestinal barrier function. Our findings indicated that HM0539 has potential to become a useful agent for prevention and treatment of intestinal barrier dysfunction- related diseases

    The Genome of Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae): Adaptation for Success

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    The lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), is a major global pest of cereal grains. Infestations are difficult to control as larvae feed inside grain kernels, and many populations are resistant to both contact insecticides and fumigants. We sequenced the genome of R. dominica to identify genes responsible for important biological functions and develop more targeted and efficacious management strategies. The genome was assembled from long read sequencing and long-range scaffolding technologies. The genome assembly is 479.1 Mb, close to the predicted genome size of 480.4 Mb by flow cytometry. This assembly is among the most contiguous beetle assemblies published to date, with 139 scaffolds, an N50 of 53.6 Mb, and L50 of 4, indicating chromosome-scale scaffolds. Predicted genes from biologically relevant groups were manually annotated using transcriptome data from adults and different larval tissues to guide annotation. The expansion of carbohydrase and serine peptidase genes suggest that they combine to enable efficient digestion of cereal proteins. A reduction in the copy number of several detoxification gene families relative to other coleopterans may reflect the low selective pressure on these genes in an insect that spends most of its life feeding internally. Chemoreceptor genes contain elevated numbers of pseudogenes for odorant receptors that also may be related to the recent ontogenetic shift of R. dominica to a diet consisting primarily of stored grains. Analysis of repetitive sequences will further define the evolution of bostrichid beetles compared to other species. The data overall contribute significantly to coleopteran genetic research

    Conditional normalizing flows for IceCube event reconstruction

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    Galactic Core-Collapse Supernovae at IceCube: “Fire Drill” Data Challenges and follow-up

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    The next Galactic core-collapse supernova (CCSN) presents a once-in-a-lifetime opportunity to make astrophysical measurements using neutrinos, gravitational waves, and electromagnetic radiation. CCSNe local to the Milky Way are extremely rare, so it is paramount that detectors are prepared to observe the signal when it arrives. The IceCube Neutrino Observatory, a gigaton water Cherenkov detector below the South Pole, is sensitive to the burst of neutrinos released by a Galactic CCSN at a level >10σ. This burst of neutrinos precedes optical emission by hours to days, enabling neutrinos to serve as an early warning for follow-up observation. IceCube\u27s detection capabilities make it a cornerstone of the global network of neutrino detectors monitoring for Galactic CCSNe, the SuperNova Early Warning System (SNEWS 2.0). In this contribution, we describe IceCube\u27s sensitivity to Galactic CCSNe and strategies for operational readiness, including "fire drill" data challenges. We also discuss coordination with SNEWS 2.0

    All-Energy Search for Solar Atmospheric Neutrinos with IceCube

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    The interaction of cosmic rays with the solar atmosphere generates a secondary flux of mesons that decay into photons and neutrinos – the so-called solar atmospheric flux. Although the gamma-ray component of this flux has been observed in Fermi-LAT and HAWC Observatory data, the neutrino component remains undetected. The energy distribution of those neutrinos follows a soft spectrum that extends from the GeV to the multi-TeV range, making large Cherenkov neutrino telescopes a suitable for probing this flux. In this contribution, we will discuss current progress of a search for the solar neutrino flux by the IceCube Neutrino Observatory using all available data since 2011. Compared to the previous analysis which considered only high-energy muon neutrino tracks, we will additionally consider events produced by all flavors of neutrinos down to GeV-scale energies. These new events should improve our analysis sensitivity since the flux falls quickly with energy. Determining the magnitude of the neutrino flux is essential, since it is an irreducible background to indirect solar dark matter searches
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