850 research outputs found
Pollution, Shadow Economy and Corruption: Theory and Evidence
We study how the shadow economy affects pollution and how this effect depends on corruption levels in public administration. Production in the shadow economy allows firms to avoid environmental regulation policies; a large informal sector may be accompanied by higher pollution levels. Our theoretical model predicts that controlling the levels of corruption can limit the effect of the shadow economy on pollution. We use panel data covering the period from 1999–2005 from more than 100 countries to test this theoretical prediction. Our estimates confirm that the relationship between the shadow economy and the levels of pollution are dependent on the levels of corruption. Our results hold when we control for the effects of other determinants of pollution, time varying common shocks, country-fixed effects and various additional covariates.environmental pollution, shadow economy, corruption, panel data
Pollution, shadow economy and corruption: Theory and evidence
We study how the shadow economy affects pollution and how this effect depends on corruption levels in public administration. Production in the shadow economy allows firms to avoid environmental regulation policies; a large informal sector may be accompanied by higher pollution levels. Our theoretical model predicts that controlling the levels of corruption can limit the effect of the shadow economy on pollution. We use panel data covering the period from 1999-2005 from more than 100 countries to test this theoretical prediction. Our estimates confirm that the relationship between the shadow economy and the levels of pollution are dependent on the levels of corruption. Our results hold when we control for the effects of other determinants of pollution, time varying common shocks, country-fixed effects and various additional covariates
Exploring the hidden impact of the Covid-19 pandemic: The role of urbanization
We examine the role of residential environments (urban/rural) in understanding the impact of the COVID-19 pandemic and the restrictions in nationwide movement on several socio-economic attitudes. We conducted large-scale surveys in four European countries (France, Germany, Spain, and the United Kingdom) before and after nationwide lockdowns were implemented. We investigate how the pandemic affected: (i) economic (economic insecurity), (ii) political (trust in domestic and international institutions), and (iii) social attitudes (loneliness), by controlling for the degree of urbanization, obtained from the geocodes of the survey respondents. Our results show that taking the degree of urbanization into account is not only relevant but is also essential. Compared to urban areas, in rural areas lockdowns led to a greater increase of economic insecurity and to a greater decrease in trust in domestic institutions. We also show that these results are particularly valid for women and households with children
Ability of detecting and willingness to share fake news
By conducting large-scale surveys in Germany and the United Kingdom, we investigate the individual-level determinants of the ability to detect fake news and the inclination to share it. We distinguish between deliberate and accidental sharing of fake news. We document that accidental sharing is much more common than deliberate sharing. Furthermore, our results indicate that older, male, high-income, and politically left-leaning respondents better detect fake news. We also find that accidental sharing decreases with age and is more prevalent among right-leaning respondents. Deliberate sharing of fake news is more prevalent among younger respondents in the United Kingdom. Finally, our results imply that respondents have a good assessment of their ability to detect fake news: those we identified as accidental sharers were also more likely to have admitted to having shared fake news
The variable radio-to-X-ray spectrum of the magnetar XTE J1810-197
We have observed the 5.54s anomalous X-ray pulsar XTE J1810-197 at radio,
millimeter, and infrared (IR) wavelengths, with the aim of learning about its
broad-band spectrum. At the IRAM 30m telescope, we have detected the magnetar
at 88 and 144GHz, the highest radio-frequency emission ever seen from a pulsar.
At 88GHz we detected numerous individual pulses, with typical widths ~2ms and
peak flux densities up to 45Jy. Together with nearly contemporaneous
observations with the Parkes, Nancay, and Green Bank telescopes, we find that
in late 2006 July the spectral index of the pulsar was -0.5<alpha<0 over the
range 1.4-144GHz. Nine dual-frequency Very Large Array and Australia Telescope
Compact Array observations in 2006 May-September are consistent with this
finding, while showing variability of alpha with time. We infer from the IRAM
observations that XTE J1810-197 remains highly linearly polarized at millimeter
wavelengths. Also, toward this pulsar, the transition frequency between strong
and weak scattering in the interstellar medium may be near 50GHz. At Gemini, we
detected the pulsar at 2.2um in 2006 September, at the faintest level yet
observed, K_s=21.89+-0.15. We have also analyzed four archival IR Very Large
Telescope observations (two unpublished), finding that the brightness
fluctuated within a factor of 2-3 over a span of 3 years, unlike the monotonic
decay of the X-ray flux. Thus, there is no correlation between IR and X-ray
flux, and it remains uncertain whether there is any correlation between IR and
radio flux.Comment: Accepted for publication in ApJ; contains improved discussion of
infrared uncertaintie
Transition-Metal-Doping of CaO as Catalyst for the OCM Reaction, a Reality Check
In this study, first-row transition metal-doped calcium oxide materials (Mn, Ni, Cr, Co., and Zn) were synthesized, characterized, and tested for the OCM reaction. Doped carbonate precursors were prepared by a co-precipitation method. The synthesis parameters were optimized to yield materials with a pure calcite phase, which was verified by XRD. EPR measurements on the doped CaO materials indicate a successful substitution of Ca2+ with transition metal ions in the CaO lattice. The materials were tested for their performance in the OCM reaction, where a beneficial effect towards selectivity and activity effect could be observed for Mn, Ni, and Zn-doped samples, where the selectivity of Co- and Cr-doped CaO was strongly reduced. The optimum doping concentration could be identified in the range of 0.04-0.10 atom%, showing the strongest decrease in the apparent activation energy, as well as the maximum increase in selectivity
XPOL - the correlation polarimeter at the IRAM 30m telescope
XPOL, the first correlation polarimeter at a large millimeter telescope, uses
a flexible digital correlator to measure all four Stokes parameters
simultaneously, i.e. the total power I, the linear polarization components Q
and U, and the circular polarization V. The versatility of the backend provides
adequate bandwidth for efficient continuum observations as well as sufficient
spectral resolution (40 kHz) for observations of narrow lines. We demonstrate
that the polarimetry specific calibrations are handled with sufficient
precision, in particular the relative phase between the Observatory's two
orthogonally linearly polarized receivers. The many facets of instrumental
polarization are studied at 3mm wavelength in all Stokes parameters: on-axis
with point sources and off-axis with beam maps. Stokes Q which is measured as
the power difference between the receivers is affected by instrumental
polarization at the 1.5% level. Stokes U and V which are measured as cross
correlations are very little affected (maximum sidelobes 0.6% (U) and 0.3%
(V)). These levels critically depend on the precision of the receiver
alignment. They reach these minimum levels set by small ellipticities of the
feed horns when alignment is optimum (<~ 0.3"). A second critical prerequisite
for low polarization sidelobes turned out to be the correct orientation of the
polarization splitter grid. Its cross polarization properties are modeled in
detail. XPOL observations are therefore limited only by receiver noise in
Stokes U and V even for extended sources. Systematic effects set in at the 1.5%
level in observations of Stokes Q. With proper precautions, this limitation can
be overcome for point sources. Stokes Q observations of extended sources are
the most difficult with XPOL.Comment: 31 pages, accepted for publication by Publications of the
Astronomical Society of the Pacific on 2008/05/2
MicroRNA-24 regulates vascularity after myocardial infarction
BACKGROUND: Myocardial infarction leads to cardiac remodeling and development of heart failure. Insufficient myocardial capillary density after myocardial infarction has been identified as a critical event in this process, although the underlying mechanisms of cardiac angiogenesis are mechanistically not well understood. METHODS AND RESULTS: Here, we show that the small noncoding RNA microRNA-24 (miR-24) is enriched in cardiac endothelial cells and considerably upregulated after cardiac ischemia. MiR-24 induces endothelial cell apoptosis, abolishes endothelial capillary network formation on Matrigel, and inhibits cell sprouting from endothelial spheroids. These effects are mediated through targeting of the endothelium-enriched transcription factor GATA2 and the p21-activated kinase PAK4, which were identified by bioinformatic predictions and validated by luciferase gene reporter assays. Respective downstream signaling cascades involving phosphorylated BAD (Bcl-XL/Bcl-2-associated death promoter) and Sirtuin1 were identified by transcriptome, protein arrays, and chromatin immunoprecipitation analyses. Overexpression of miR-24 or silencing of its targets significantly impaired angiogenesis in zebrafish embryos. Blocking of endothelial miR-24 limited myocardial infarct size of mice via prevention of endothelial apoptosis and enhancement of vascularity, which led to preserved cardiac function and survival. CONCLUSIONS: Our findings indicate that miR-24 acts as a critical regulator of endothelial cell apoptosis and angiogenesis and is suitable for therapeutic intervention in the setting of ischemic heart disease. [KEYWORDS: Animals, Apoptosis/drug effects, Arterioles/pathology, Capillaries/pathology, Cell Hypoxia, Cells, Cultured/drug effects/metabolism, Collagen, Drug Combinations, Drug Evaluation, Preclinical, Endothelial Cells/ metabolism/pathology, GATA2 Transcription Factor/biosynthesis/genetics, Gene Expression Profiling, Heart Failure/etiology, Heme Oxygenase-1/biosynthesis/genetics, Laminin, Male, Mice, Mice, Inbred C57BL, MicroRNAs/antagonists & inhibitors/genetics/ physiology, Myocardial Infarc
Observations of the Goldreich-Kylafis effect in star-forming regions with XPOL at the IRAM 30m telescope
The Goldreich-Kylafis (GK) effect causes certain molecular line emission to
be weakly linearly polarized, e.g., in the presence of a magnetic field.
Compared to polarized dust emission, the GK effect has the potential to yield
additional information along the line of sight through its dependence on
velocity in the line profile. Our goal was to detect polarized molecular line
emission toward the DR21(OH), W3OH/H2O, G34.3+0.2, and UYSO1 dense molecular
cloud cores in transitions of rare CO isotopologues and CS. The feasibility of
such observations had to be established by studying the influence of polarized
sidelobes, e.g., in the presence of extended emission in the surroundings of
compact sources. The observations were carried out with the IRAM 30m telescope
employing the correlation polarimeter XPOL and using two orthogonally polarized
receivers. We produced beam maps to investigate instrumental polarization.
While in nearly all transitions toward all sources a polarized signal is found,
its degree of polarization only in one case surpasses the polarization that can
be expected due to instrumental effects. It is shown that any emission in the
polarized sidelobes of the system can produce instrumental polarization, even
if the source is unpolarized. Tentative evidence for astronomically polarized
line emission with pL<~1.5% was found in the CS(2-1) line toward G34.3+0.2.Comment: 10 pages, 6 figures, accepted for publication in A&
Identity and inequality misperceptions, demographic determinants and efficacy of corrective measures
By conducting two waves of large-scale surveys in the United Kingdom and Germany, we investigate the determinants of identity and inequality misperceptions. We first show that people substantially overestimate the share of immigrants, Muslims, people under the poverty line, and the income share of the richest. Moreover, women, lower-income, and lower-educated respondents generally have higher misperceptions. Only income share misperceptions are associated more with people who place themselves on the left of the political spectrum. In contrast, the other three misperceptions are more prevalent among those who place themselves to the right. We then attempt to correct misperceptions by conducting a classic controlled experiment. Specifically, we randomly assign respondents into a treatment group informed about their initial misperceptions and a control group left uninformed. Our results indicate that information treatments had some corrective effects on misperceptions in Germany but were ineffective in the United Kingdom. Moreover, information treatments in Germany were more effective for men, centrists, and highly educated respondents. There is also no evidence of spill-over effects: correcting one misperception does not have corrective effects for the other misperceptions
- …