79 research outputs found
The Trade-Climate Nexus: Assessing the European Unionâs Institutionalist Approach. College of Europe EU Diplomacy Paper 04/2019
The European Union (EU) is considered a global leader both in trade and climate policies. Nonetheless, trade liberalisation has been widely criticised for its negative effects on the environment and for directly contributing to the rising levels of annual greenhouse gas emissions. This paper addresses the trade-climate nexus by assessing to what extent the EU is effectively integrating its environmental objectives within its trade policies. First, the legal spaces for the EUâs action in this policy nexus are identified. Second, the analysis looks into how effectively the EU is achieving its own set of objectives for trade and climate. The assessment draws on an innovative analytical matrix examining four Trade-Climate Agenda items: (i) international competitiveness, (ii) climate-friendly goods and services, (iii) international aviation and maritime shipping, and (iv) product labelling and standards. The paper then evaluates to what extent the externalisation mechanisms of Mannersâ âNormative Power Europeâ and Damroâs âMarket Power Europeâ are deployed in order to achieve the above objectives. The findings show that the EUâs performance in the effective management of the nexus is overall moderate to weak
X-ray and radio bursts from the magnetar 1E 1547.0-5408
We report on simultaneous radio and X-ray observations of the radio-emitting magnetar 1E 1547.0-5408 on 2009 January 25 and February 3, with the 64 m Parkes radio telescope and the Chandra and XMM-Newton X-ray observatories. The magnetar was observed in a period of intense X-ray bursting activity and enhanced X-ray emission. We report here on the detection of two radio bursts from 1E 1547.0-5408 reminiscent of fast radio bursts (FRBs). One of the radio bursts was anticipated by âŒ1 s (about half a rotation period of the pulsar) by a bright SGR-like X-ray burst, resulting in a F/F ⌠10. Radio pulsations were not detected during the observation showing the FRB-like radio bursts, while they were detected in the previous radio observation. We also found that the two radio bursts are neither aligned with the latter radio pulsations nor with the peak of the X-ray pulse profile (phase shift of âŒ0.2). Comparing the luminosity of these FRB-like bursts and those reported from SGR 1935 +2154, we find that the wide range in radio efficiency and/or luminosity of magnetar bursts in the Galaxy may bridge the gap between âordinaryâ pulsar radio bursts and the extragalactic FRB phenomenon.G.L.I. and L.S. acknowledge funding from ASI-INAF agreements I/037/12/0 and 2017-14-H.O. G.L.I. and A.T. acknowledge financial support from the Italian MIUR PRIN
grant 2017LJ39LM. M.B., A.P., and L.S. acknowledge funding from the grant âiPeskaâ (INAF PRIN-SKA/CTA; PI Possenti). N.R. is supported by the ERC Consolidator Grant âMAGNESIAâ (nr.817661), and by grants SGR2017-1383 and PGC2018-095512-BI00. We acknowledge the support of the PHAROS COST Action (CA16214)
Salinity and ABA Seed Responses in Pepper: Expression and Interaction of ABA Core Signaling Components
Abscisic acid (ABA) plays an important role in various aspects of plant growth and development, including adaptation to stresses, fruit development and ripening. In seeds, ABA participates through its core signaling components in dormancy instauration, longevity determination, and inhibition of germination in unfavorable environmental conditions such as high soil salinity. Here, we show that seed germination in pepper was delayed but only marginally reduced by ABA or NaCl with respect to control treatments. Through a similarity search, pepper orthologs of ABA core signaling components PYL (PYRABACTIN RESISTANCE1-LIKE), PP2C (PROTEIN PHOSPHATASE2C), and SnRK2 (SUCROSE NONFERMENTING1 (SNF1)-RELATED PROTEIN KINASE2) genes were identified. Gene expression analyses of selected members showed a low abundance of PYL and SnRK2 transcripts in dry seeds compared to other tissues, and an up-regulation at high concentrations of ABA and/or NaCl for both positive and negative regulators of ABA signaling. As expected, in hydroponically-grown seedlings exposed to NaCl, only PP2C encoding genes were up-regulated. Yeast two hybrid assays performed among putative pepper core components and with Arabidopsis thaliana orthologs confirmed the ability of the identified proteins to function in ABA signaling cascade, with the exception of a CaABI isoform cloned from seeds. BiFC assay in planta confirmed some of the interactions obtained in yeast. Altogether, our results indicate that a low expression of perception and signaling components in pepper seeds might contribute to explain the observed high percentages of seed germination in the presence of ABA. These results might have direct implications on the improvement of seed longevity and vigor, a bottleneck in pepper breeding
Lunar Gravitational-Wave Antenna
Monitoring of vibrational eigenmodes of an elastic body excited by
gravitational waves was one of the first concepts proposed for the detection of
gravitational waves. At laboratory scale, these experiments became known as
resonant-bar detectors first developed by Joseph Weber in the 1960s. Due to the
dimensions of these bars, the targeted signal frequencies were in the kHz
range. Weber also pointed out that monitoring of vibrations of Earth or Moon
could reveal gravitational waves in the mHz band. His Lunar Surface Gravimeter
experiment deployed on the Moon by the Apollo 17 crew had a technical failure
rendering the data useless. In this article, we revisit the idea and propose a
Lunar Gravitational-Wave Antenna (LGWA). We find that LGWA could become an
important partner observatory for joint observations with the space-borne,
laser-interferometric detector LISA, and at the same time contribute an
independent science case due to LGWA's unique features. Technical challenges
need to be overcome for the deployment of the experiment, and development of
inertial vibration sensor technology lays out a future path for this exciting
detector concept.Comment: 29 pages, 17 figure
X-ray polarimetry reveals the magnetic field topology on sub-parsec scales in Tycho's supernova remnant
Supernova remnants are commonly considered to produce most of the Galactic
cosmic rays via diffusive shock acceleration. However, many questions about the
physical conditions at shock fronts, such as the magnetic-field morphology
close to the particle acceleration sites, remain open. Here we report the
detection of a localized polarization signal from some synchrotron X-ray
emitting regions of Tycho's supernova remnant made by the Imaging X-ray
Polarimetry Explorer. The derived polarization degree of the X-ray synchrotron
emission is 9+/-2% averaged over the whole remnant, and 12+/-2% at the rim,
higher than the 7-8% polarization value observed in the radio band. In the west
region the polarization degree is 23+/-4%. The X-ray polarization degree in
Tycho is higher than for Cassiopeia A, suggesting a more ordered magnetic-field
or a larger maximum turbulence scale. The measured tangential polarization
direction corresponds to a radial magnetic field, and is consistent with that
observed in the radio band. These results are compatible with the expectation
of turbulence produced by an anisotropic cascade of a radial magnetic-field
near the shock, where we derive a magnetic-field amplification factor of
3.4+/-0.3. The fact that this value is significantly smaller than those
expected from acceleration models is indicative of highly anisotropic
magnetic-field turbulence, or that the emitting electrons either favor regions
of lower turbulence, or accumulate close to where the magnetic-field
orientation is preferentially radially oriented due to hydrodynamical
instabilities.Comment: 31 pages, 7 figures, 3 tables. Accepted for publication in ApJ.
Revised versio
Observations of 4U 1626-67 with the Imaging X-ray Polarimetry Explorer
We present measurements of the polarization of X-rays in the 2-8 keV band
from the pulsar in the ultracompact low mass X-ray binary 4U1626-67 using data
from the Imaging X-ray Polarimetry Explorer (IXPE). The 7.66 s pulsations were
clearly detected throughout the IXPE observations as well as in the NICER soft
X-ray observations, which we use as the basis for our timing analysis and to
constrain the spectral shape over 0.4-10 keV energy band. Chandra HETGS
high-resolution X-ray spectra were also obtained near the times of the IXPE
observations for firm spectral modeling. We find an upper limit on the
pulse-averaged linear polarization of <4% (at 95% confidence). Similarly, there
was no significant detection of polarized flux in pulse phase intervals when
subdividing the bandpass by energy. However, spectropolarimetric modeling over
the full bandpass in pulse phase intervals provide a marginal detection of
polarization of the power-law spectral component at the 4.8 +/- 2.3% level (90%
confidence). We discuss the implications concerning the accretion geometry onto
the pulsar, favoring two-component models of the pulsed emission.Comment: 19 pages, 7 figures, 7 tables; accepted for publication in the
Astrophysical Journa
IXPE and XMM-Newton observations of the Soft Gamma Repeater SGR 1806-20
Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two
anomalous X-ray pulsars provided evidence that X-ray emission from magnetar
sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton
observations of the soft {\gamma}-repeater SGR 1806-20. The spectral and timing
properties of SGR 1806-20 derived from XMM-Newton data are in broad agreement
with previous measurements; however, we found the source at an all-time-low
persistent flux level. No significant polarization was measured apart from the
4-5 keV energy range, where a probable detection with PD=31.6\pm 10.5% and
PA=-17.6\pm 15 deg was obtained. The resulting polarization signal, together
with the upper limits we derive at lower and higher energies 2-4 and 5-8 keV,
respectively) is compatible with a picture in which thermal radiation from the
condensed star surface is reprocessed by resonant Compton scattering in the
magnetosphere, similar to what proposed for the bright magnetar 4U 0142+61.Comment: 11 pages, 3 figures, accepted for publication in Ap
The Polarized Cosmic Hand: IXPE Observations of PSR B1509-58/MSH 15-52
We describe IXPE polarization observations of the Pulsar Wind Nebula (PWN)
MSH15-52, the `Cosmic Hand'. We find X-ray polarization across the PWN, with B
field vectors generally aligned with filamentary X-ray structures. High
significance polarization is seen in arcs surrounding the pulsar and toward the
end of the `jet', with polarization degree PD>70%, thus approaching the maximum
allowed synchrotron value. In contrast, the base of the jet has lower
polarization, indicating a complex magnetic field at significant angle to the
jet axis. We also detect significant polarization from PSR B1509-58 itself.
Although only the central pulse-phase bin of the pulse has high individual
significance, flanking bins provide lower significance detections and, in
conjunction with the X-ray image and radio polarization, can be used to
constrain rotating vector model solutions for the pulsar geometry.Comment: To appear in the Astrophysical Journa
Magnetic structures and turbulence in SN 1006 revealed with imaging X-ray polarimetry
Young supernova remnants (SNRs) strongly modify surrounding magnetic fields,
which in turn play an essential role in accelerating cosmic rays (CRs). X-ray
polarization measurements probe magnetic field morphology and turbulence at the
immediate acceleration site. We report the X-ray polarization distribution in
the northeastern shell of SN1006 from a 1 Ms observation with the Imaging X-ray
Polarimetry Explorer (IXPE). We found an average polarization degree of
and an average polarization angle of
(measured on the plane of the sky from north to east). The X-ray polarization
angle distribution reveals that the magnetic fields immediately behind the
shock in the northeastern shell of SN 1006 are nearly parallel to the shock
normal or radially distributed, similar to that in the radio observations, and
consistent with the quasi-parallel CR acceleration scenario. The X-ray emission
is marginally more polarized than that in the radio band. The X-ray
polarization degree of SN 1006 is much larger than that in Cas A and Tycho,
together with the relatively tenuous and smooth ambient medium of the remnant,
favoring that CR-induced instabilities set the turbulence in SN 1006 and CR
acceleration is environment-dependent.Comment: 15 pages, 4 Figures, 2 Tables; accepted for publication in The
Astrophysical Journa
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