7,034 research outputs found
Enabling science with Gaia observations of naked-eye stars
ESA's Gaia space astrometry mission is performing an all-sky survey of
stellar objects. At the beginning of the nominal mission in July 2014, an
operation scheme was adopted that enabled Gaia to routinely acquire
observations of all stars brighter than the original limit of G~6, i.e. the
naked-eye stars. Here, we describe the current status and extent of those
observations and their on-ground processing. We present an overview of the data
products generated for G<6 stars and the potential scientific applications.
Finally, we discuss how the Gaia survey could be enhanced by further exploiting
the techniques we developed.Comment: 16 pages, 8 figures. Submitted for the proceedings of the 2016 SPIE
Astronomical Instrumentation and Telescopes conference (SPIE 9904
Policy Shocks and Stock Market Returns: Evidence from Chinese Solar Panels
We examine the stock market performance of publicly-listed Chinese firms in the solar panel industry over 2012 and 2013 in response to announcements of new import restrictions by the European Union and domestic policy changes by the Chinese government. Using daily stock market prices from the Shanghai-Shenzhen, New York and Hong Kong markets, we calculate abnormal returns to several policy changes affecting solar panels produced in China. We find, consistent with the Melitz (2003) model, that larger, more export-oriented firms experienced larger stock market losses in the wake of European trade restriction announcements. We further show that European trade policy had a larger negative effect on Chinese private sector firms relative to state owned enterprises. Finally, we use a two stage least squares estimation technique to show that firms listed on US markets are more responsive to news events than those listed in China and Hong Kong
The post-test analysis of ablative materials Final report, 11 Jul. 1967 - 15 May 1968
Ablative materials examination before and after test firin
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Dominant Currency Dynamics: Evidence on Dollar-invoicing from UK Exporters
How do the choices of individual firms contribute to the dominance of a currency in global trade? Using export transactions data from the UK over 2010-2016, we document strong evidence of two mechanisms that promote the use of a dominant currency: (1) prior experience: the probability that a firm invoices its exports to a new market in a dominant currency is increasing in the number of years the firm has used the dominant currency in its existing markets; (2) strategic complementarity: a firm is more likely to invoice its exports in the currency chosen by the majority of its competitors in a foreign destination market in order to stabilize its residual demand in that market
Travelling waves in a drifting flux lattice
Starting from the time-dependent Ginzburg-Landau (TDGL) equations for a type
II superconductor, we derive the equations of motion for the displacement field
of a moving vortex lattice without inertia or pinning. We show that it is
linearly stable and, surprisingly, that it supports wavelike long-wavelength
excitations arising not from inertia or elasticity but from the
strain-dependent mobility of the moving lattice. It should be possible to image
these waves, whose speeds are a few \mu m/s, using fast scanning tunnelling
microscopy.Comment: 4 pages, revtex, 2 .eps figures imbedded in paper, title shortened,
minor textual change
Digging supplementary buried channels: investigating the notch architecture within the CCD pixels on ESA's Gaia satellite
The European Space Agency (ESA) Gaia satellite has 106 CCD image sensors
which will suffer from increased charge transfer inefficiency (CTI) as a result
of radiation damage. To aid the mitigation at low signal levels, the CCD design
includes Supplementary Buried Channels (SBCs, otherwise known as `notches')
within each CCD column. We present the largest published sample of Gaia CCD SBC
Full Well Capacity (FWC) laboratory measurements and simulations based on 13
devices. We find that Gaia CCDs manufactured post-2004 have SBCs with FWCs in
the upper half of each CCD that are systematically smaller by two orders of
magnitude (<50 electrons) compared to those manufactured pre-2004 (thousands of
electrons). Gaia's faint star (13 < G < 20 mag) astrometric performance
predictions by Prod'homme et al. and Holl et al. use pre-2004 SBC FWCs as
inputs to their simulations. However, all the CCDs already integrated onto the
satellite for the 2013 launch are post-2004. SBC FWC measurements are not
available for one of our five post-2004 CCDs but the fact it meets Gaia's image
location requirements suggests it has SBC FWCs similar to pre-2004. It is too
late to measure the SBC FWCs onboard the satellite and it is not possible to
theoretically predict them. Gaia's faint star astrometric performance
predictions depend on knowledge of the onboard SBC FWCs but as these are
currently unavailable, it is not known how representative of the whole focal
plane the current predictions are. Therefore, we suggest Gaia's initial
in-orbit calibrations should include measurement of the onboard SBC FWCs. We
present a potential method to do this. Faint star astrometric performance
predictions based on onboard SBC FWCs at the start of the mission would allow
satellite operating conditions or CTI software mitigation to be further
optimised to improve the scientific return of Gaia.Comment: Accepted for publication in MNRAS, 16 pages, 19 figure
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Invoicing and the Dynamics of Pricing-to-market: Evidence from UK Export Prices around the Brexit Referendum
We provide micro-econometric evidence that, following the large and persistent sterling depreciation after the Brexit referendum, on impact, exchange rate pass-through (ERPT) was complete for transactions invoiced in producer currency and low for sales invoiced either in a vehicle or in the destination market currency. Yet these differences strikingly narrowed within six quarters. A weaker currency did not translate into a persistent gain in price competitiveness for UK exports. At a granular level we find that UK exporters invoice in multiple currencies ̶ even when shipping a product to the same destination ̶ and switch currencies over time. Remarkably, we fail to detect significant changes in the relative shares of invoicing currencies in response to the Brexit shock. Last but not least, we find that UK firms price-to-market, i.e., adjust markups to bilateral exchange rate and CPI movements, only when they invoice sales in the destination-market currency
The Looming Threat of Tariff Hikes: Entry into Exporting Under Trade Agreement Renegotiation
Since the end of World War II, trade policy around the world has been characterized by a tendency toward greater liberalization. Among developed countries, almost all reductions in import tariffs and relaxation of quantitative restrictions have been negotiated under multilateral, preferential, or bilataral trade agreements. Countries engaged in these negotiations have sought to reduce trade barriers relative to the existing level of protectin - the threat point in the event of a breakdown in negotiations has generally been a continuation of the status quo
Inheritance of Gray Leaf Spot Resistance in Corn
Gray leaf spot disease, caused by Cercospora zeae-maydis Tehon and Daniels, has become a significant disease in Iowa corn (Zea mays L.) production. Incidence of gray leaf spot has increased with the increased use of conservation tillage practices. The inheritance of resistance to gray leaf spot was studied via use of generation mean analyses for five crosses and via use of 100 S1 progenies developed from an F2 population. Experiments were conducted at two locations that included either natural or artificial inoculation with C. zeae-maydis spores. Additive and dominance effects were significant in nearly all instances. Heritability for gray leaf spot resistance among S1 progenies was 0.78. Because resistance seemed to be determined by additive genetic variation, it seems selection for greater resistance to gray leaf spot can be effective. In all instances, the level of gray leaf spot resistance in single-cross hybrids was improved, whether the single-cross hybrid was produced with either one or both parents having resistance. It seems single-cross hybrids will have adequate levels of resistance to gray leaf spot if at least one of the parents has resistance
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