5,626 research outputs found
Support schemes for renewable electricity in the EU
This paper discusses the level and design of support schemes used to promote renewable electricity in Europe. A theoretical model is presented to determine optimal renewable energy policies. Policies that solely aim to address environmental externalities and energy security risks are unlikely to make renewable power technologies competitive. Learning effects and spillovers are necessary to justify the need for support schemes. The analysis suggests that feed-in premiums guaranteed in addition to the electricity market price should be preferred over feed-in tariffs, which provide the eligible power producer with a guaranteed price. The premiums should be time limited and frequently reviewed. Once the technology becomes competitive, tradable green certificates would be a more suitable support instrument. As regards wind energy, the available estimates of externalities suggest that levels are probably too high in many Member States. In addition, the current promotion of photovoltaics could possibly be more cost-efficient if it targeted technology development more directly.european union, eu, setzer, wolff, van den Noord, euro area, money, heterogeneity, money holdings
Maternal Medication Use and Risk of Hypospadias- An Exposure Spectrum Approach
Purpose To investigate associations between maternal use of selected medications during early pregnancy and the risk of hypospadias in male infants.
Methods We used data from the National Birth Defects Prevention Study, a multi-site, population-based, case-control study. We analyzed data from 1,537 case infants with second or third degree isolated hypospadias and 4,314 male control infants born from 1997-2007. Exposure was based on reported use of any prescription or over-the-counter medication or herbal product, for which there were at least 5 exposed cases, from 1 month before to 4 months after conception, excluding topicals, vitamins, minerals, and products for which the components were unknown. Adjusted odds ratios (aORs) and 95% confidence intervals (CI) were estimated using multivariable logistic regression, adjusting for several confounders.
Results Of the 195 medication components with at least 5 exposed cases, 89 components met the inclusion criteria and were assessed-28 herbal and 61 non-herbal components. Hypospadias was associated with reported use of cephalexin (aOR 3.06; 95% CI 1.02, 9.18), phenylpropanolamine HCl (aOR 2.68; 95% CI 1.06, 6.80), and ibuprofen (aOR 1.16; 95% CI 1.00, 1.34), in primary analyses.
Conclusions We replicated a previously observed association between maternal exposure to phenylpropanolamine HCl and hypospadias. The associations with cephalexin and ibuprofen have not previously been reported. Given the exploratory nature of the analyses, these results should be considered hypothesis-generating. Better understanding of the potential fetal effects will allow clinicians and women of childbearing age to make more informed decisions regarding the use of medications during pregnancy
Assessment of GDP forecast uncertainty
This paper develops an approach to measure the uncertainty surrounding expected GDP growth that prevails in the economy. This is accomplished by making use of consensus forecasts of GDP growth and by studying the properties of distributions of forecasted euro area GDP growth. A euro area distribution is constructed from the mean distributions of individual country specific consensus forecasts. Information contained in the distributions can be used to make uncertainty assessments of future economic development. The paper shows that uncertainty varies over time, and how the levels can be compared with a historical mean and between different time periods. Furthermore, the paper shows that the constructed distributions can be asymmetric as measured by their skewness. This information can be used to assess whether risks are on the upside, or the downside. Two graphs are proposed to be used as a regular monitoring tool, illustrating the measured uncertainty and balance of risks.GDP, economic growth, GDP growth, forecasts, forecast uncertainty, Lind�n, GDP forecast
Cellular automata on regular rooted trees
We study cellular automata on regular rooted trees. This includes the
characterization of sofic tree shifts in terms of unrestricted Rabin automata
and the decidability of the surjectivity problem for cellular automata between
sofic tree shifts
Complexity Measures from Interaction Structures
We evaluate new complexity measures on the symbolic dynamics of coupled tent
maps and cellular automata. These measures quantify complexity in terms of
-th order statistical dependencies that cannot be reduced to interactions
between units. We demonstrate that these measures are able to identify
complex dynamical regimes.Comment: 11 pages, figures improved, minor changes to the tex
Beetroot Juice Supplementation Lowers Oxygen Cost of Vigorous Intensity Aerobic Exercise in Trained Endurance Athletes
Please see the pdf version of the abstract
Fe I Oscillator Strengths for the Gaia-ESO Survey
The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale
study of multi-element chemical abundances of some 100 000 stars in the Milky
Way with the ultimate aim of quantifying the formation history and evolution of
young, mature and ancient Galactic populations. However, in preparing for the
analysis of GES spectra, it has been noted that atomic oscillator strengths of
important Fe I lines required to correctly model stellar line intensities are
missing from the atomic database. Here, we present new experimental oscillator
strengths derived from branching fractions and level lifetimes, for 142
transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38
are urgently needed by GES. We also assess the impact of these new data on
solar spectral synthesis and demonstrate that for 36 lines that appear
unblended in the Sun, Fe abundance measurements yield a small line-by-line
scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with
recent publications.Comment: Accepted for publication in Mon. Not. R. Astron. So
Cosmic Needles versus Cosmic Microwave Background Radiation
It has been suggested by a number of authors that the 2.7K cosmic microwave
background (CMB) radiation might have arisen from the radiation from Population
III objects thermalized by conducting cosmic graphite/iron needle-shaped dust.
Due to lack of an accurate solution to the absorption properties of exceedingly
elongated grains, in existing literature which studies the CMB thermalizing
process they are generally modelled as (1) needle-like spheroids in terms of
the Rayleigh approximation; (2) infinite cylinders; and (3) the antenna theory.
We show here that the Rayleigh approximation is not valid since the Rayleigh
criterion is not satisfied for highly conducting needles. We also show that the
available intergalactic iron dust, if modelled as infinite cylinders, is not
sufficient to supply the required opacity at long wavelengths to obtain the
observed isotropy and Planckian nature of the CMB. If appealing to the antenna
theory, conducting iron needles with exceedingly large elongations (10^4)
appear able to provide sufficient opacity to thermalize the CMB within the iron
density limit. But the applicability of the antenna theory to exceedingly thin
needles of nanometer/micrometer in thickness needs to be justified.Comment: 13 pages, 4 figures; submitted to ApJ
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