The Global Chilling Effects of Antidumping Proliferation

Advocates of antidumping (AD) laws downplay their effects by arguing that the trade flows that are subject to AD are small and their distortions negligible.This paper is the first to counter that notion by quantifying the worldwide effect of AD laws on aggregate trade flows.The recent proliferation of AD laws across countries provides us with a natural experiment to estimate the trade effects of adopting versus using AD laws; differences in the intensity of use among countries with older AD laws allow us to investigate reputation effects.For this purpose, we estimate worldwide trade flows using a gravity equation spanning 21 years (1980-2000) of annual observations.Our estimates confirm that AD effects are not small.Among other findings, new tough users have their aggregate imports depressed by 15.7 billion US$a year (or 6.7$ on top of the cumulative negative effect of reputation.For some countries, the dampening effects of AD laws on trade flows are found to nearly offset the gains from trade liberalization.antidumping;gravity equation;trade liberalization;trade flows

Occurrence of pharmaceuticals in environmental samples: a multi-analyte approach

Pharmaceuticals and their residues in the environment have been recently recognized as one of the emerging research areas in the environmental chemistry and toxicology and caused them to be viewed as a new class of priority substances. It has been reportedthat they are introduced continuously in the environment via household use, effluents from Sewage Treatment Plants (STPs) and animal excreta. Up to date, the potential human, animal and ecological risk associated with the occurrence of these compounds in the environment is not well documented. There is an increased attention due to the fact that they are designed to have specific effects at low doses and to be resistant to Moreover, the science of mixture toxicity is complex and to date quite unknown (Bound et al., 2006; Hernando et al., 2006).Despite the increased research and regulatory interest in the occurrence of pharmaceuticals and their degradation products in STPs effluents and freshwater ecosystems (Hernando et al., 2006), the occurrence, the distribution between the different environmental compartments (i.e. water, sediments, suspended solids and aqueous organisms), the trophic transfer and their potential toxicity is to date far less documented (Emblidge and DeLorenze, 2006).In this sense, this study will present a detection method for the determination of a large group of pharmaceuticals (i.e. antibiotics, beta-agonists, painkillers, tranquilizers, nonsteroidal anti-inflammatory drugs) used both in human and veterinary practice in environmental samples using Liquid Chromatography coupled to multiple Mass Spectrometry

Characterization of the optical properties of the buried contact of the JWST MIRI Si:As infrared blocked impurity band detectors

The Mid-Infrared Instrument MIRI on-board the James Webb Space Telescope uses three Si:As impurity band conduction detector arrays. MIRI medium resolution spectroscopic measurements (R$\sim$3500-1500) in the 5~$\mu m$ to 28~$\mu m$ wavelength range show a 10-30\% modulation of the spectral baseline; coherent reflections of infrared light within the Si:As detector arrays result in fringing. We quantify the shape and impact of fringes on spectra of optical sources observed with MIRI during ground testing and develop an optical model to simulate the observed modulation. We use our optical model in conjunction with the MIRI spectroscopic data to show that the properties of the buried contact inside the MIRI Si:As detector have a significant effect on the fringing behavior.Comment: 11 pages, 7 figures, SPIE Astronomical Telescopes + Instrumentation 2020, submitted to SPI

Desorption of CO and O2 interstellar ice analogs

Solid O2 has been proposed as a possible reservoir for oxygen in dense clouds through freeze-out processes. The aim of this work is to characterize quantitatively the physical processes that are involved in the desorption kinetics of CO-O2 ices by interpreting laboratory temperature programmed desorption (TPD) data. This information is used to simulate the behavior of CO-O2 ices under astrophysical conditions. The TPD spectra have been recorded under ultra high vacuum conditions for pure, layered and mixed morphologies for different thicknesses, temperatures and mixing ratios. An empirical kinetic model is used to interpret the results and to provide input parameters for astrophysical models. Binding energies are determined for different ice morphologies. Independent of the ice morphology, the desorption of O2 is found to follow 0th-order kinetics. Binding energies and temperature-dependent sticking probabilities for CO-CO, O2-O2 and CO-O2 are determined. O2 is slightly less volatile than CO, with binding energies of 912+-15 versus 858+-15 K for pure ices. In mixed and layered ices, CO does not co-desorb with O2 but its binding energies are slightly increased compared with pure ice whereas those for O2 are slightly decreased. Lower limits to the sticking probabilities of CO and O2 are 0.9 and 0.85, respectively, at temperatures below 20K. The balance between accretion and desorption is studied for O2 and CO in astrophysically relevant scenarios. Only minor differences are found between the two species, i.e., both desorb between 16 and 18K in typical environments around young stars. Thus, clouds with significant abundances of gaseous CO are unlikely to have large amounts of solid O2.Comment: 8 pages + 2 pages online material, 8 figures (1 online), accepted by A&

Formation of hydrogen peroxide and water from the reaction of cold hydrogen atoms with solid oxygen at 10K

The reactions of cold H atoms with solid O2 molecules were investigated at 10 K. The formation of H2O2 and H2O has been confirmed by in-situ infrared spectroscopy. We found that the reaction proceeds very efficiently and obtained the effective reaction rates. This is the first clear experimental evidence of the formation of water molecules under conditions mimicking those found in cold interstellar molecular clouds. Based on the experimental results, we discuss the reaction mechanism and astrophysical implications.Comment: 12 pages, 3 Postscript figures, use package amsmath, amssymb, graphic

Molecular ions in L1544. II. The ionization degree

The maps presented in Paper I are here used to infer the variation of the column densities of HCO+, DCO+, N2H+, and N2D+ as a function of distance from the dust peak. These results are interpreted with the aid of a crude chemical model which predicts the abundances of these species as a function of radius in a spherically symmetric model with radial density distribution inferred from the observations of dust emission at millimeter wavelengths and dust absorption in the infrared. Our main observational finding is that the N(N2D+)/N(N2H+) column density ratio is of order 0.2 towards the L1544 dust peak as compared to N(DCO+)/N(HCO+) = 0.04. We conclude that this result as well as the general finding that N2H+ and N2D+ correlate well with the dust is caused by CO being depleted to a much higher degree than molecular nitrogen in the high density core of L1544. Depletion also favors deuterium enhancement and thus N2D+, which traces the dense and highly CO-depleted core nucleus, is much more enhanced than DCO+. Our models do not uniquely define the chemistry in the high density depleted nucleus of L1544 but they do suggest that the ionization degree is a few times 10^{-9} and that the ambipolar diffusion time scale is locally similar to the free fall time. It seems likely that the lower limit which one obtains to ionization degree by summing all observable molecular ions is not a great underestimate of the true ionization degree. We predict that atomic oxygen is abundant in the dense core and, if so, H3O+ may be the main ion in the central highly depleted region of the core.Comment: 31 pages, 8 figures, to be published in Ap

Cryptochromes are the key photoreceptors mediating Arabidopsis inflorescence stem movements under natural sunlight

Inflorescence stem movements in response to natural sunlight are widely spread across angiosperm species and are suggested to increase reproductive success. However, the underlying mechanisms that mediate this phototropic response to natural irradiation are unclear. We studied phototropic responses of Arabidopsis inflorescences in both laboratory and field conditions and report an action spectrum at wavelengths below 500 nm, mediated by several photoreceptor families. In controlled conditions, UVR8 is the key photoreceptor for narrowband UV-B radiation while phototropins and cryptochromes are crucial for phototropic responses to narrowband blue light. At low blue irradiances, phototropins are dominant while cryptochromes are essential during high blue irradiances but subjected to the negative control of phototropins. Importantly, cryptochromes are the principal photoreceptors mediating inflorescence stem bending under full sunlight

Constraints on the gas content of the Fomalhaut debris belt. Can gas-dust interactions explain the belt's morphology?

Context: The 440 Myr old main-sequence A-star Fomalhaut is surrounded by an eccentric debris belt with sharp edges. This sort of a morphology is usually attributed to planetary perturbations, but the orbit of the only planetary candidate detected so far, Fomalhaut b, is too eccentric to efficiently shape the belt. Alternative models that could account for the morphology without invoking a planet are stellar encounters and gas-dust interactions. Aims: We aim to test the possibility of gas-dust interactions as the origin of the observed morphology by putting upper limits on the total gas content of the Fomalhaut belt. Methods: We derive upper limits on the CII 158 $\mu$m and OI 63 $\mu$m emission by using non-detections from the Photodetector Array Camera and Spectrometer (PACS) onboard the Herschel Space Observatory. Line fluxes are converted into total gas mass using the non-local thermodynamic equilibrium (non-LTE) code RADEX. We consider two different cases for the elemental abundances of the gas: solar abundances and abundances similar to those observed for the gas in the $\beta$ Pictoris debris disc. Results: The gas mass is shown to be below the millimetre dust mass by a factor of at least $\sim$3 (for solar abundances) respectively $\sim$300 (for $\beta$ Pic-like abundances). Conclusions: The lack of gas co-spatial with the dust implies that gas-dust interactions cannot efficiently shape the Fomalhaut debris belt. The morphology is therefore more likely due to a yet unseen planet (Fomalhaut c) or stellar encounters.Comment: 5 pages, 3 figures, published in A&A; versions 2 and 3: language editin

The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel. I. Evidence of clumps, multiple arcs, and a linear bar-like structure

Context. The interaction between stellar winds and the interstellar medium (ISM) can create complex bow shocks. The photometers on board the Herschel Space Observatory are ideally suited to studying the morphologies of these bow shocks. Aims. We aim to study the circumstellar environment and wind-ISM interaction of the nearest red supergiant, Betelgeuse. Methods. Herschel PACS images at 70, 100, and 160 micron and SPIRE images at 250, 350, and 500 micron were obtained by scanning the region around Betelgeuse. These data were complemented with ultraviolet GALEX data, near-infrared WISE data, and radio 21 cm GALFA-HI data. The observational properties of the bow shock structure were deduced from the data and compared with hydrodynamical simulations. Results. The infrared Herschel images of the environment around Betelgeuse are spectacular, showing the occurrence of multiple arcs at 6-7 arcmin from the central target and the presence of a linear bar at 9 arcmin. Remarkably, no large-scale instabilities are seen in the outer arcs and linear bar. The dust temperature in the outer arcs varies between 40 and 140 K, with the linear bar having the same colour temperature as the arcs. The inner envelope shows clear evidence of a non-homogeneous clumpy structure (beyond 15 arcsec), probably related to the giant convection cells of the outer atmosphere. The non-homogeneous distribution of the material even persists until the collision with the ISM. A strong variation in brightness of the inner clumps at a radius of 2 arcmin suggests a drastic change in mean gas and dust density some 32 000 yr ago. Using hydrodynamical simulations, we try to explain the observed morphology of the bow shock around Betelgeuse. Conclusions: [abbreviated]Comment: 26 page