64,024 research outputs found
Markups, bargaining power and offshoring: an empirical assessment
This paper tests the pro-competitive effect of imports on product and labour markets for Spanish manufacturing firms in the period 1990-2005. In doing so, it takes into account the type of imported products: final vs intermediate. Markups are estimated following the procedure suggested by Roeger (1995) and including an efficient bargaining model. The observed heterogeneity among firms is parameterized to consider additional product standardization and market concentration. The results support the Imports as Market Discipline hypothesis for importers of final goods, while firms that offshore intermediate inputs show similar markups to non-importers. Additionally, the union bargaining power is smaller the more final-goods oriented imports are and the more homogeneous is the type of goods elaborated by firms.Markups, offshoring, bargaining power
IRRIGATION TECHNOLOGY INVESTMENT WHEN THE PRICE OF WATER IS STOCHASTIC
The paper considers the effect of changes in the distribution of water price on the incentives to adopt water-conserving irrigation technologies. A two-stage decision model is developed wherein agents make long-term decisions about irrigation technology investments and decide production levels based on short-term realizations of water price. Comparative statics results show that the impact of changes in the distribution of water price hinge on the responsiveness of cultivated acreage to fluctuations in the price of water. The model is tested using data on irrigation technology investment from California's San Joaquin Valley. Econometric results strongly support the conceptual model, and show that changes in the distribution of water price have systematically different impacts on permanent and annual crops.Resource /Energy Economics and Policy,
Second harmonic generation from metallic arrays of rectangular holes
The generation process of second harmonic (SH) radiation from holes
periodically arranged on a metal surface is investigated. Three main modulating
factors affecting the optical response are identified: the near-field
distribution at the wavelength of the fundamental harmonic, how SH light
couples to the diffraction orders of the lattice, and its propagation
properties inside the holes. It is shown that light generated at the second
harmonic can excite electromagnetic modes otherwise inaccessible in the linear
regime under normal incidence illumination. It is demonstrated that the
emission of SH radiation is only allowed along off-normal paths precisely due
to that symmetry. Two different regimes are studied in the context of
extraordinary optical transmission, where enhanced linear transmission either
occurs through localized electromagnetic modes or is aided by surface plasmon
polaritons (SPPs). While localized resonances in metallic hole arrays have been
previously investigated, the role played by SPPs in SH generation has not been
addressed so far. In general, good agreement is found between our calculations
(based on the finite difference time domain method) and the experimental
results on localized resonances, even though no free fitting parameters were
used in describing the materials. It is found that SH emission is strongly
modulated by enhanced fields at the fundamental wavelength (either localized or
surface plasmon modes) on the glass metal interface. This is so in the
transmission side but also in reflection, where emission can only be explained
by an efficient tunneling of SH photons through the holes from the output to
the input side. Finally, the existence of a dark SPP at the fundamental field
is identified through a noninvasive method for the first time, by analyzing the
efficiency and far-field pattern distribution in transmission at the second
harmonic.Comment: This paper was published in JOSA B and is made available as an
electronic reprint with the permission of OSA. The paper can be found at the
following URL on the OSA website:
http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-32-1-15.
Systematic or multiple reproduction or distribution to multiple locations via
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Developing Scenarios for Product Longevity and Sufficiency
This paper explores the narrative of peoples’ relationships with products as a window on understanding the types of innovation that may inform a culture of sufficiency. The work forms part of the 'Business as Unusual: Designing Products with Consumers in the Loop' [BaU] project, funded as part of the UK EPSRC-ESRC RECODE network (RECODE, 2016) that aims to explore the potential of re-distributed manufacturing (RdM) in a context of sustainability. This element of the project employed interviews, mapping and workshops as methods to investigate the relationship between people and products across the product lifecycle. A focus on product longevity and specifically the people-product interactions is captured in conversations around product maintenance and repair. In exploring ideas of ‘broken’ we found different characteristics of, and motivations for, repair. Mapping these and other product-people interactions across the product lifecycle indicated where current activity is, who owns such activity (i.e. organisation or individual) and where gaps in interactions occur. These issues were explored further in a workshop which grouped participants to look at products from the perspective of one of four scenarios; each scenario represented either short or long product lifespans and different types of people engagement in the design process. The findings help give shape to new scenarios for designing sufficiency-based social models of material flows
The power spectrum of solar convection flows from high-resolution observations and 3D simulations
We compare Fourier spectra of photospheric velocity fields from very high
resolution IMaX observations to those from recent 3D numerical
magnetoconvection models. We carry out a proper comparison by synthesizing
spectral lines from the numerical models and then applying to them the adequate
residual instrumental degradation that affects the observational data. Also,
the validity of the usual observational proxies is tested by obtaining
synthetic observations from the numerical boxes and comparing the velocity
proxies to the actual velocity values from the numerical grid.
For the observations, data from the SUNRISE/IMaX instrument with about 120 km
spatial resolution are used, thus allowing the calculation of observational
Fourier spectra well into the subgranular range. For the simulations, we use
four series of runs obtained with the STAGGER code and synthesize the IMaX
spectral line (FeI 5250.2 A) from them. Proxies for the velocity field are
obtained via Dopplergrams (vertical component) and local correlation tracking
(horizontal component).
A very good match between observational and simulated Fourier power spectra
is obtained for the vertical velocity data for scales between 200 km and 6 Mm.
Instead, a clear vertical shift is obtained when the synthetic observations are
not degraded. The match for the horizontal velocity data is much less
impressive because of the inaccuracies of the LCT procedure. Concerning the
internal comparison of the direct velocity values of the numerical boxes with
those from the synthetic observations, a high correlation (0.96) is obtained
for the vertical component when using the velocity values on the
log() = -1 surface in the box. The corresponding Fourier spectra are
near each other. A lower maximum correlation (0.5) is reached (at =
1) for the horizontal velocities as a result of the coarseness of the LCT
procedure.Comment: 12 pages, 9 figures, accepted in A&
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