266 research outputs found
The sovereign yield curve and credit ratings in GIIPS
© 2020 International Review of Finance Ltd. 2020 This paper studies the impact of sovereign credit rating and outlook changes on the shape of the sovereign yield curve using data for five European countries, namely, Greece, Ireland, Italy, Portugal, and Spain, known as the GIIPS for the period of 2001–2016. We use the dynamic Nelson–Siegel model to estimate the level, slope, and curvature of the yield curve. Subsequently, we employ the vector autoregressive model to estimate the effect of sovereign rating and outlook changes on the sovereign yield curve. We find a significant effect of rating downgrades and an insignificant effect of rating upgrades in all five countries; however, the results for the effect of changes in outlook status are mixed. Our results remain robust to various sensitivity tests
Federal tax policies, congressional voting and natural resources
Can abundance of natural resources affect legislators' voting behaviour over federal tax policies? We construct a political economy model of a federalized economy with district heterogeneity in natural resource abundance. The model shows that representatives of natural resource-rich districts are more (less) willing to vote in favour of federal tax increases (decreases). This occurs because resource-rich districts are less responsive to federal tax changes due to the immobile nature of their natural resources. We test the model's predictions using data on roll-call votes in the US House of Representatives over the major federal tax bills initiated during the period of 1945–2003, in conjunction with the presence of active giant oil fields in US congressional districts. Our identification strategy rests on plausibly exogenous giant oil field discoveries and exploitation and narrative-based aggregate federal tax shocks that are exogenous to individual congressional districts and legislators. We find that: (i) resource-rich congressional districts are less responsive to changes in federal taxes and (ii) representatives of resource-rich congressional districts are more (less) supportive of federal tax increases (decreases), controlling for legislator, congressional district and state indicators. Our results indicate that resource richness is approximately half as dominant as the main determinant, namely party affiliation, in driving legislators' voting behaviour over federal tax policies
Mid-infrared laser light nulling experiment using single-mode conductive waveguides
Aims: In the context of space interferometry missions devoted to the search
of exo-Earths, this paper investigates the capabilities of new single mode
conductive waveguides at providing modal filtering in an infrared and
monochromatic nulling experiment; Methods: A Michelson laser interferometer
with a co-axial beam combination scheme at 10.6 microns is used. After
introducing a Pi phase shift using a translating mirror, dynamic and static
measurements of the nulling ratio are performed in the two cases where modal
filtering is implemented and suppressed. No additional active control of the
wavefront errors is involved. Results: We achieve on average a statistical
nulling ratio of 2.5e-4 with a 1-sigma upper limit of 6e-4, while a best null
of 5.6e-5 is obtained in static mode. At the moment, the impact of external
vibrations limits our ability to maintain the null to 10 to 20 seconds.;
Conclusions: A positive effect of SM conductive waveguide on modal filtering
has been observed in this study. Further improvement of the null should be
possible with proper mechanical isolation of the setup.Comment: Accepted in A&A, 7 pages, 5 figure
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Conference on Housing, Stability, and the Macroeconomy: International Perspectives
This article provides an introduction to the JMCB special issue on housing bubbles, the global financial crisis, and the ensuing recessions in countries that experienced housing busts. We focus on five themes that are important for policymakers and researchers alike: the domestic and international factors driving housing booms and busts, the relevance of the housing sector for the real economy, how monetary policy should react to housing booms and busts, how housing and mortgage finance reform could affect financial stability, and the broad lessons learned for macroeconomics and macroprudential policy
(2-Bromoacetyl)ferrocene
In the title molecule, [Fe(C5H5)(C7H6BrO)], the C atoms of the substituted ring have disparate Fe—C bond lengths compared with the unsubstituted ring. In the bromoacetyl residue, the Br and O atoms are co-planar [the O—C—C—Br torsion angle is 5.7 (4)°] and are syn to each other. Helical supramolecular chains along the b axis are formed in the crystal structure mediated by C—H⋯O contacts; the carbonyl-O atom is bifurcated. The chains are linked into layers by C—H⋯π(unsubstituted ring) interactions that stack along the a-axis direction
Advances in the Development of Mid-Infrared Integrated Devices for Interferometric Arrays
This article reports the advances on the development of mid-infrared
integrated optics for stellar interferometry. The devices are fabricated by
laser writing techniques on chalcogenide glasses. Laboratory characterizaton is
reported and analyzed.Comment: 12 pages, 9 figures, SPIE Astronomical Telescopes and Instrumentatio
Multiple-length-scale elastic instability mimics parametric resonance of nonlinear oscillators
Spatially confined rigid membranes reorganize their morphology in response to
the imposed constraints. A crumpled elastic sheet presents a complex pattern of
random folds focusing the deformation energy while compressing a membrane
resting on a soft foundation creates a regular pattern of sinusoidal wrinkles
with a broad distribution of energy. Here, we study the energy distribution for
highly confined membranes and show the emergence of a new morphological
instability triggered by a period-doubling bifurcation. A periodic
self-organized focalization of the deformation energy is observed provided an
up-down symmetry breaking, induced by the intrinsic nonlinearity of the
elasticity equations, occurs. The physical model, exhibiting an analogy with
parametric resonance in nonlinear oscillator, is a new theoretical toolkit to
understand the morphology of various confined systems, such as coated materials
or living tissues, e.g., wrinkled skin, internal structure of lungs, internal
elastica of an artery, brain convolutions or formation of fingerprints.
Moreover, it opens the way to new kind of microfabrication design of
multiperiodic or chaotic (aperiodic) surface topography via self-organization.Comment: Submitted for publicatio
Increasing the imaging capabilities of the VLTI using integrated optics
Several scientific topics linked to the observation of extended structures around astrophysical sources (dust torus around AGN, disks around young stars, envelopes around AGBs) require imaging capability with milli-arcsecond spatial resolution. The current VLTI instruments, AMBER and MIDI, will provide in the coming months the required high angular resolution, yet without actual imaging. As a rule of thumb, the image quality accessible with an optical interferometer is directly related to the number of telescopes used simultaneously: the more the apertures, the better and the faster the reconstruction of the image. We propose an instrument concept to achieve interferometric combination of N telescopes (4 ≤ N ≤ 8) thanks to planar optics technology: 4 x 8-m telescopes in the short term and/or 8 x 1.8-m telescopes in the long term. The foreseen image reconstruction quality in the visible and/or in the near infrared will be equivalent to the one achieved with millimeter radio interferometers. Achievable spatial resolution will be better than the one foreseen with ALMA. This instrument would be able to acquire routinely 1 mas resolution images. A 13 to 20 magnitude sensitivity in spectral ranges from 0.6 to 2.5 μm is expected depending on the choice of the phase referencing guide source. High dynamic range, even on faint objects, is achievable thanks to the high accuracy provided by integrated optics for visibility amplitude and phase measurements. Based on recent validations of integrated optics presented here an imaging instrument concept can be proposed. The results obtained using the VLTI facilities give a demonstration of the potential of the proposed technique
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