776 research outputs found

    How to manage speculative shocks: intra-European vs. International monetary coordination

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    The literature on currency crisis has generally not answered to the following question: which economic policies may reduce the contagion effects of a speculative shock? We use a dynamic Mundell-Fleming model extended to four countries and compute three time-consistent equilibria: a Nash equilibrium, and Nash-bargaining equilibria, first between the central banks of the G3 (a target zone equilibrium) and, second between European governments and the ECB. The best equilibrium for the Fed, European and Japanese policymakers is intra-European coordination. It induces a very expansionary fiscal policy in the USA whose government hence rejects it. Extensions to the case of a Stability Pact in European countries do not alter our results. Introducing a Fed less conservative than the ECB or the BoJ provokes a change in US preferences: both authorities give priority to the monetary equilibrium and the US government is no longer isolationist.

    Is the Unitarity of the quark-mixing-CKM-matrix violated in neutron β\beta-decay?

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    We report on a new measurement of neutron β\beta-decay asymmetry. From the result \linebreak A0A_0 = -0.1189(7), we derive the ratio of the axial vector to the vector coupling constant λ\lambda = gA/gV{\it g_A/g_V} = -1.2739(19). When included in the world average for the neutron lifetime τ\tau = 885.7(7)s, this gives the first element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix VudV_{ud} . With this value and the Particle Data Group values for VusV_{us} and VubV_{ub}, we find a deviation from the unitarity condition for the first row of the CKM matrix of Δ\Delta = 0.0083(28), which is 3.0 times the stated error

    Sharpening Low-Energy, Standard-Model Tests via Correlation Coefficients in Neutron Beta-Decay

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    The correlation coefficients a, A, and B in neutron beta-decay are proportional to the ratio of the axial-vector to vector weak coupling constants, g_A/g_V, to leading recoil order. With the advent of the next generation of neutron decay experiments, the recoil-order corrections to these expressions become experimentally accessible, admitting a plurality of Standard Model (SM) tests. The measurement of both a and A, e.g., allows one to test the conserved-vector-current (CVC) hypothesis and to search for second-class currents (SCC) independently. The anticipated precision of these measurements suggests that the bounds on CVC violation and SCC from studies of nuclear beta-decay can be qualitatively bettered. Departures from SM expectations can be interpreted as evidence for non-V-A currents.Comment: 4 pages, REVTeX, intro. broadened, typos fixed, to appear in PR

    Plastid proteome prediction for diatoms and other algae with secondary plastids of the red lineage

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    The plastids of ecologically and economically important algae from phyla such as stramenopiles, dinoflagellates and cryptophytes were acquired via a secondary endosymbiosis and are surrounded by three or four membranes. Nuclear-encoded plastid-localized proteins contain N-terminal bipartite targeting peptides with the conserved amino acid sequence motif ‘ASAFAP’. Here we identify the plastid proteomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum, using a customized prediction tool (ASAFind) that identifies nuclear-encoded plastid proteins in algae with secondary plastids of the red lineage based on the output of SignalP and the identification of conserved ‘ASAFAP’ motifs and transit peptides. We tested ASAFind against a large reference dataset of diatom proteins with experimentally confirmed subcellular localization and found that the tool accurately identified plastid-localized proteins with both high sensitivity and high specificity. To identify nucleus-encoded plastid proteins of T. pseudonana and P. tricornutum we generated optimized sets of gene models for both whole genomes, to increase the percentage of full-length proteins compared with previous assembly model sets. ASAFind applied to these optimized sets revealed that about 8% of the proteins encoded in their nuclear genomes were predicted to be plastid localized and therefore represent the putative plastid proteomes of these algae

    Low molecular weight organic acid salts, markers of old fungi activity in wall paintings

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    Micro-Infrared Spectroscopy (mSR-FTIR) and X-ray diffraction (mSR-XRD) with synchrotron light, Gas Chromatography/Mass Spectrometry (CG/MS), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM/EDS) were used to identify and obtain the distribution of complex mixtures of calcium salts of low molecular weight organic acids (LMWOA) in micro-layered micro-samples. Filamentous fungi produce LMWOA that can react with metal cations producing stable salts. These substances were found in the dark spots covering the surfaces of Saint Michael's Chapel wall paintings of the Royal Monastery of Pedralbes in Barcelona linking them to old fungi activity. The presence of glycerol likewise related to the fungi activity is also identified in the layers.Postprint (author's final draft

    In silico-designed lignin peroxidase from Phanerochaete chrysosporium shows enhanced acid stability for depolymerization of lignin

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    Background: The lignin peroxidase isozyme H8 from the white-rot fungus Phanerochaete chrysosporium (LiPH8) demonstrates a high redox potential and can efficiently catalyze the oxidation of veratryl alcohol, as well as the degradation of recalcitrant lignin. However, native LiPH8 is unstable under acidic pH conditions. This characteristic is a barrier to lignin depolymerization, as repolymerization of phenolic products occurs simultaneously at neutral pH. Because repolymerization of phenolics is repressed at acidic pH, a highly acid-stable LiPH8 could accelerate the selective depolymerization of recalcitrant lignin. Results: The engineered LiPH8 was in silico designed through the structural superimposition of surface-active site-harboring LiPH8 from Phanerochaete chrysosporium and acid-stable manganese peroxidase isozyme 6 (MnP6) from Ceriporiopsis subvermispora. Effective salt bridges were probed by molecular dynamics simulation and changes to Gibbs free energy following mutagenesis were predicted, suggesting promising variants with higher stability under extremely acidic conditions. The rationally designed variant, A55R/N156E-H239E, demonstrated a 12.5-fold increased half-life under extremely acidic conditions, 9.9-fold increased catalytic efficiency toward veratryl alcohol, and a 7.8-fold enhanced lignin model dimer conversion efficiency compared to those of native LiPH8. Furthermore, the two constructed salt bridges in the variant A55R/N156E-H239E were experimentally confirmed to be identical to the intentionally designed LiPH8 variant using X-ray crystallography (PDB ID: 6A6Q). Conclusion: Introduction of strong ionic salt bridges based on computational design resulted in a LiPH8 variant with markedly improved stability, as well as higher activity under acidic pH conditions. Thus, LiPH8, showing high acid stability, will be a crucial player in biomass valorization using selective depolymerization of lignin

    Evolution of the genus Eucricetodon (Rodentia, Mammalia) from the Valley of Lakes (Mongolia): a taxonomical description and update on the stratigraphical distribution

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    The Oligocene fossil deposits from Valley of Lakes in Central Mongolia have provided a wealth of rodent fossils. Among these, cricetids are a very important part. To date, only the Miocene genera have been described in detail. Here, we focus on the Oligocene genus Eucricetodon from this region. Eucricetodontinae are the most abundant fossils in the Oligocene Valley of Lakes faunas. The present study consists of the description of five species of cricetid rodents from 43 localities ranging in age from the early Oligocene to the early-late Oligocene. In addition to Eucricetodon asiaticus described in Mongolia in 1923, we have found Eucricetodon bagus and Eucricetodon jilantaiensis that were described from Nei Mongol and Eucricetodon occidentalis discovered in Kazakhstan. This taxonomical study provides new information regarding the evolution of the Cricetidae in Central and Eastern Asia during the Oligocene and, more particularly, regarding their phylogenetic relationships and the evolutionary trends

    A new species of Argyromys (Rodentia, Mammalia) from the oligocene of the valley of lakes (Mongolia): its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan

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    We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene

    Low mass dimuon production in proton and ion induced interactions at SPS

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    The low mass dimuon spectra collected in p-U collisions by the NA38 experiment significantly exceeds the total cross section expected from previous analysis, done by other experiments. The `excess' events have a harder \pt\ distribution than the muon pairs from η\eta and ω\omega Dalitz decays, expected to dominate the mass window 0.4--0.65~GeV/c2c^2. We conjecture that the excess events might be due to \qqbar\ annihilations, negligible at low \pt\ but made visible by the \mt\ cut applied in the NA38 data. Taking this assumption to parametrise the p-U spectra, we proceed with the analysis of the S-Cu, S-U and Pb-Pb data, collected by the NA38 and NA50 experiments, where we find that the measured mass spectra does not seem to exceed the expected low mass `cocktail' by more than 20\,\%

    Near Real-Time Monitoring of Formaldehyde in a Low-Energy School Building

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    International audienceThe emergence of new super-insulated buildings to reduce energy consumption places the quality of indoor air at the center of the debate. Among the indoor air pollutants, aldehydes are often present, and formaldehyde is of major interest regarding its multiple sources and its health impact. Therefore, French regulations expect to reduce formaldehyde concentrations below 10 μg m −3 in public buildings by 2023. Formaldehyde and other aldehydes were measured for two weeks during an intensive field campaign conducted in a school recently built and equipped with programmable dual-flow ventilation. Aldehydes were monitored with the ISO 16000-3 reference method based on sampling with 2,4-dinitrophenylhydrazine (DNPH) tubes while formaldehyde concentration was continuously measured by using a sensitive near real-time formaldehyde microanalyzer with a detection limit of 1 μg m −3. Formaldehyde was the major aldehyde. Its concentrations varied in the range of 2-25 μg m −3 and decreased by half when mechanical ventilation was ON, while the other ones were always below 5 μg m −3. In addition, an excellent agreement was observed between the different analytical techniques deployed to quantify formaldehyde levels. The microanalyzer was able to measure fast variations of formaldehyde concentration in the studied room, according to the building's ventilation periods
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