366 research outputs found
FDI and domestic investments in Germany: crowding in or out?
This paper estimates the effects of outward FDI on domestic business investment in Germany at the industry level for a panel of 19 industry and 10 services sectors in Germany. We pay particular attention to the different motivations behind FDI, and distinguishbetween FDI to high versus low wage countries, to Europe versus the rest of the world, and FDI in services and industry sectors.We find thatin industry FDI to low-wage countries crowds out domestic investment, whereas FDI to high wage countries outside Europe crowds in domestic investment. In services, FDI to Western Europe crowds in domestic investment
Measuring Environmental Inequality
This study presents alternative measures of environmental inequality in the 50 U.S. states for exposure to industrial air pollution. We examine three methodological issues. First, to what extent are environmental inequality measures sensitive to spatial scale and population weighting? Second, how do sensitivities to different segments of the overall distribution affect rankings by these measures? Third, how do vertical and horizontal (inter-group) inequality measures relate to each other? We find substantive differences in rankings by different measures and conclude that no single indicator is sufficient for addressing the entire range of equity concerns that are relevant to environmental policy; instead multiple measures are needed
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Effects of Carbon Mitigation on Co-pollutants at Industrial Facilities in Europe
In addition to global climate benefits, carbon mitigation improves local air quality by reducing emissions of hazardous co-pollutants. Using data on large industrial point sources in Europe, we estimate how changes in carbon dioxide emissions affect emissions of the three co-pollutants SOX, NOX, and PM10 for samples of 727 to 2,653 facilities for the years 2007 to 2015. We find substantial and significant co-pollutant elasticities of 0.7 for SOX and NOX, and 0.5 for PM10, which are robust to different estimation approaches. Large CO2 emitters and the energy sector are characterized by higher-than-average co-pollutant elasticities. For climate policy induced CO2 emission reductions we find co-pollutant elasticities in the energy sector of 1.2 for SOX, 1.0 for NOX, and 0.8 for PM10. Using these estimates to calculate monetary air quality co- benefits suggests that conventional European Environmental Agency estimates of carbon damages that omit co-benefits significantly underestimate the benefits of carbon mitigation
Observability of radiation pressure shot noise in optomechanical systems
We present a theoretical study of an experiment designed to detect radiation
pressure shot noise in an optomechanical system. Our model consists of a
coherently driven optical cavity mode that is coupled to a mechanical
oscillator. We examine the cross-correlation between two quadratures of the
output field from the cavity. We determine under which circumstances radiation
pressure shot noise can be detected by a measurement of this cross-correlation.
This is done in the general case of nonzero detuning between the frequency of
the drive and the cavity resonance frequency. We study the qualitative features
of the different contributions to the cross-correlator and provide quantitative
figures of merit for the relative importance of the radiation pressure shot
noise contribution to other contributions. We also propose a modified setup of
this experiment relevant to the "membrane-in-the-middle" geometry, which
potentially can avoid the problems of static bistability and classical noise in
the drive.Comment: 12 pages + 4 page appendix, 10 figure
Sociodemographic Disparities in Ambient Particulate Matter Exposure in Austria
We assess to what extent municipalities with socioeconomically vulnerable populations are disproportionately exposed to particulate matter in Austria using municipality level data on particulate matter exposure from the European Environmental Agency and sociodemographic data from Statistics Austria for 2015. We find that foreign citizens are exposed to higher levels of particulate matter in Austria. This finding is robust with regards to different controls, regional fixed effects, and different particulate matter exposure indicators. Exposure disparities by citizenship are stronger in urban areas, where the large majority of foreign citizens live. We also find that citizens with low educational attainment are exposed to higher levels of particulate matter. The latter disparities are stronger in rural areas, where the majority of people with low educational attainment live. The relationship between income and air pollution follows an inverted U-shape in most specifications. High turning points and wide Fieller confidence intervals, however, suggest that the relationship is positive for most of the distribution and insignificant or negative for very high incomes. Overall, we find evidence that socioeconomically vulnerable municipalities are exposed to higher levels of particulate matter
Strong and Tunable Nonlinear Optomechanical Coupling in a Low-Loss System
A major goal in optomechanics is to observe and control quantum behavior in a
system consisting of a mechanical resonator coupled to an optical cavity. Work
towards this goal has focused on increasing the strength of the coupling
between the mechanical and optical degrees of freedom; however, the form of
this coupling is crucial in determining which phenomena can be observed in such
a system. Here we demonstrate that avoided crossings in the spectrum of an
optical cavity containing a flexible dielectric membrane allow us to realize
several different forms of the optomechanical coupling. These include cavity
detunings that are (to lowest order) linear, quadratic, or quartic in the
membrane's displacement, and a cavity finesse that is linear in (or independent
of) the membrane's displacement. All these couplings are realized in a single
device with extremely low optical loss and can be tuned over a wide range in
situ; in particular, we find that the quadratic coupling can be increased three
orders of magnitude beyond previous devices. As a result of these advances, the
device presented here should be capable of demonstrating the quantization of
the membrane's mechanical energy.Comment: 12 pages, 4 figures, 1 tabl
Suppression of extraneous thermal noise in cavity optomechanics
Extraneous thermal motion can limit displacement sensitivity and radiation
pressure effects, such as optical cooling, in a cavity-optomechanical system.
Here we present an active noise suppression scheme and its experimental
implementation. The main challenge is to selectively sense and suppress
extraneous thermal noise without affecting motion of the oscillator. Our
solution is to monitor two modes of the optical cavity, each with different
sensitivity to the oscillator's motion but similar sensitivity to the
extraneous thermal motion. This information is used to imprint "anti-noise"
onto the frequency of the incident laser field. In our system, based on a
nano-mechanical membrane coupled to a Fabry-P\'{e}rot cavity, simulation and
experiment demonstrate that extraneous thermal noise can be selectively
suppressed and that the associated limit on optical cooling can be reduced.Comment: 27 pages, 14 figure
Cavity cooling of a nanomechanical resonator by light scattering
We present a novel method for opto-mechanical cooling of sub-wavelength sized
nanomechanical resonators. Our scheme uses a high finesse Fabry-Perot cavity of
small mode volume, within which the nanoresonator is acting as a
position-dependant perturbation by scattering. In return, the back-action
induced by the cavity affects the nanoresonator dynamics and can cool its
fluctuations. We investigate such cavity cooling by scattering for a nanorod
structure and predict that ground-state cooling is within reach.Comment: 4 pages, 3 figure
Bridging Physics and Biology Teaching through Modeling
As the frontiers of biology become increasingly interdisciplinary, the
physics education community has engaged in ongoing efforts to make physics
classes more relevant to life sciences majors. These efforts are complicated by
the many apparent differences between these fields, including the types of
systems that each studies, the behavior of those systems, the kinds of
measurements that each makes, and the role of mathematics in each field.
Nonetheless, physics and biology are both sciences that rely on observations
and measurements to construct models of the natural world. In the present
theoretical article, we propose that efforts to bridge the teaching of these
two disciplines must emphasize shared scientific practices, particularly
scientific modeling. We define modeling using language common to both
disciplines and highlight how an understanding of the modeling process can help
reconcile apparent differences between the teaching of physics and biology. We
elaborate how models can be used for explanatory, predictive, and functional
purposes and present common models from each discipline demonstrating key
modeling principles. By framing interdisciplinary teaching in the context of
modeling, we aim to bridge physics and biology teaching and to equip students
with modeling competencies applicable across any scientific discipline.Comment: 10 pages, 2 figures, 3 table
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