1,280 research outputs found
FDI and trade: A Granger causality analysis in a heterogeneous panel
This paper will investigate the Granger causality between outward Foreign Direct Investment (FDI) and the exports of goods and services in 11 European countries from 1996 to 2008. Using a new method to evaluate causality in a heterogeneous panel, we find that the causal relationship from FDI to exports is homogeneous among the panel. However, we find strong evidence of a heterogeneity of the causal relationship from exports to FDI in our sample.Foreign direct investment, exports, Granger causality, heterogeneous panel
Guideline on management of the acute asthma attack in children by Italian Society of Pediatrics.
BACKGROUND: Acute asthma attack is a frequent condition in children. It is one of the most common reasons for emergency department (ED) visit and hospitalization. Appropriate care is fundamental, considering both the high prevalence of asthma in children, and its life-threatening risks. Italian Society of Pediatrics recently issued a guideline on the management of acute asthma attack in children over age 2, in ambulatory and emergency department settings. METHODS: The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was adopted. A literature search was performed using the Cochrane Library and Medline/PubMed databases, retrieving studies in English or Italian and including children over age 2 year. RESULTS: Inhaled ß2 agonists are the first line drugs for acute asthma attack in children. Ipratropium bromide should be added in moderate/severe attacks. Early use of systemic steroids is associated with reduced risk of ED visits and hospitalization. High doses of inhaled steroids should not replace systemic steroids. Aminophylline use should be avoided in mild/moderate attacks. Weak evidence supports its use in life-threatening attacks. Epinephrine should not be used in the treatment of acute asthma for its lower cost / benefit ratio, compared to β2 agonists. Intravenous magnesium solphate could be used in children with severe attacks and/or forced expiratory volume1 (FEV1) lower than 60% predicted, unresponsive to initial inhaled therapy. Heliox could be administered in life-threatening attacks. Leukotriene receptor antagonists are not recommended. CONCLUSIONS: This Guideline is expected to be a useful resource in managing acute asthma attacks in children over age 2
The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?
Multi-zone chemical evolution models (CEMs), differing in the nucleosynthesis
prescriptions (yields) and prescriptions of star formation, have been computed
for the Milky Way. All models fit the observed O/H and Fe/H gradients well and
reproduce the main characteristics of the gas distribution, but they are also
designed to do so. For the C/H gradient the results are inconclusive with
regards to yields and star formation. The C/Fe and O/Fe vs. Fe/H, as well as
C/O vs. O/H trends predicted by the models for the solar neighbourhood zone
were compared with stellar abundances from the literature. For O/Fe vs. Fe/H
all models fit the data, but for C/O vs. O/H, only models with increased carbon
yields for zero-metallicity stars or an evolving initial mass function provide
good fits. Furthermore, a steep star formation threshold in the disc can be
ruled out since it predicts a steep fall-off in all abundance gradients beyond
a certain galactocentric distance (~ 13 kpc) and cannot explain the possible
flattening of the C/H and Fe/H gradients in the outer disc seen in
observations. Since in the best-fit models the enrichment scenario is such that
carbon is primarily produced in low-mass stars, it is suggested that in every
environment where the peak of star formation happened a few Gyr back in time,
winds of carbon-stars are responsible for most of the carbon enrichment.
However, a significant contribution by zero-metallicity stars, especially at
very early stages, and by winds of high-mass stars, which are increasing in
strength with metallicity, cannot be ruled out by the CEMs presented here. In
the solar neighbourhood, as much as 80%, or as little as 40% of the carbon may
have been injected to the interstellar medium by low- and intermediate-mass
stars. The stellar origin of carbon remains an open question, although
production in low- and intermediate-mass stars appears to be the simplest
explanation of observed carbon abundance trends.Comment: 13 pages, 9 figures. Accepted by Astronomy & Astrophysic
Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model
In a companion paper, we have presented the combined
asteroseismic-spectroscopic dataset obtained from CoRoT lightcurves and APOGEE
infra-red spectra for 678 solar-like oscillating red giants in two fields of
the Galactic disc (CoRoGEE). We have measured chemical abundance patterns,
distances, and ages of these field stars which are spread over a large radial
range of the Milky Way's disc. Here we show how to simulate this dataset using
a chemodynamical Galaxy model. We also demonstrate how the observation
procedure influences the accuracy of our estimated ages.Comment: 5 pages, 6 figures. To appear in Astronomische Nachrichten, special
issue "Reconstruction the Milky Way's History: Spectroscopic surveys,
Asteroseismology and Chemo-dynamical models", Guest Editors C. Chiappini, J.
Montalb\'an, and M. Steffe
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