Potential instability of gas hydrates along the chilean margin due to ocean warming

In the last few years, interest in the offshore Chilean margin has increased rapidly due to the presence of gas hydrates. We have modelled the gas hydrate stability zone off Chilean shores (from 33\ub0 S to 46\ub0 S) using a steady state approach to evaluate the effects of climate change on gas hydrate stability. Present day conditions were modelled using published literature and compared with available measurements. Then, we simulated the effects of climate change on gas hydrate stability in 50 and 100 years on the basis of Intergovernmental Panel on Climate Change and National Aeronautics and Space Administration forecasts. An increase in temperature might cause the dissociation of gas hydrate that could strongly affect gas hydrate stability. Moreover, we found that the high seismicity of this area could have a strong effect on gas hydrate stability. Clearly, the Chilean margin should be considered as a natural laboratory for understanding the relationship between gas hydrate systems and complex natural phenomena, such as climate change, slope stability and earthquakes

Basal and Frontal Accretion Processes versus BSR Characteristics along the Chilean Margin

Multichannel seismic reflection data recorded between Itata (36°S) and Coyhaique offshores (43°S) were processed to obtain seismic images. Analysis of the seismic profiles revealed that weak and discontinuous bottom simulating reflectors were associated to basal accretion processes, while strong and continuous bottom simulating reflectors were associated to frontal accretion processes. This can be explained considering that during basal accretion processes, extensional tectonic movements due to uplifting can favour fluid escapes giving origin to weaker and most discontinuous bottom simulating reflectors. During frontal accretion processes (folding and thrusting), high fluid circulation and stable tectonic conditions however can be responsible of stronger and most continuous bottom simulating reflectors. Along the Arauco-Valdivia offshores, steep accretionary prisms, normal faults, slope basins, and thicker underplated sediment bed were associated to basal accretion, while along the Itata, Chiloe and Coyhaique offshores, small accretionary prisms, folding, and thinner underplated sediment bed were associated to frontal accretion

Evaluation of non-chemical seed treatment methods for the control of Alternaria dauci and A. radicina on carrot seeds

The current study was initiated to evaluate the efficacy of physical methods (hot water, aerated steam, electron treatment) and agents of natural origin (resistance inducers, plant derived products, micro-organisms) as seed treatments of carrots for control of Alternaria dauci and A. radicina. Control of both Alternaria species by seed treatment with the resistance inducers was generally poor. Results were also not satisfactory with most of the formulated commercial micro-organism preparations. Based on the average of five field trials, one of these, BA 2552 (Pseudomonas chlororaphis), provided a low but significant increase in plant stand. Among the experimental micro-organisms, the best results were obtained with Pseudomonas sp. strain MF 416 and Clonostachys rosea strain IK726. A similar level of efficacy was provided by seed treatment with an emulsion (1%) of thyme oil in water. Good and consistent control was generally achieved with the physical methods aerated steam, hot water and electron treatment. Aerated steam treatment was, apart from the thiram-containing chemical standard, the best single treatment, and its performance may at least partially be due to extensive pre-testing, resulting in dosages optimally adapted to the respective seed lot. In some of the experiments the effect of the hot water treatment, which was tested at a fixed, not specifically adapted dosage, was significantly improved when combined with a Pseudomonas sp. MF 416 or C. rosea IK726 treatment. The results are discussed in relation to the outcome of experiments in which the same seed treatment methods and agents were tested in other seed-borne vegetable pathosystems

STOVE: Seed treatments for organic vegetable production

The aim of the EU-financed research project „STOVE“ (Seed Treatments for Organic Vegetable Production) is to evaluate different methods potentially suited for seed treatment of vegetables in organic farming regarding their efficacy, to optimise these methods, and where feasible to combine them with each other. Scientists from seven European research institutions and a producer of organic vegetable seeds carry out the project

A crustal seismic profile across Sicily

A crustal reflection seismic profile, more than 100 km long, was recorded across central Sicily, from the Tyrrhenian shore to the Sicily Channel, to understand the deep structures and the collision mechanisms between Europe and Africa and the subsequent geodynamic evolution. The profile was acquired using explosive sources and 240 active channels recorded by a Sercel 408-XL, 24 bits A/D converter, with a 12 km spread and a 24-fold coverage. The data were processed following a non-conventional procedure in order to preserve the relative amplitudes of the reflections and to better investigate the Sicily deep structures down to the Moho. The main highlighted structures are the dramatic flexure of the Iblean crust, the huge, deeper than expected, trough of Caltanissetta consisting of deep seated thrusts and nappes, and the imbricate thrust system of rigid bodies characterizing the northern Maghrebian chain. We designed an ad hoc acquisition and processing in order to highlight these main geological features in the seismic stacked section. Moreover, the deepest parts of the Caltanissetta trough are imaged for the first time, and its bottom is now fixed at more than 7 s TWT. The giant crustal wedge flexuring the Iblean foreland and the Moho geometries are examinated

Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity (E>100 MeV) averaged over $\sim$ 3 years of observations and peaking on 2010 October 14/15 at 2.9 X 10^{50} erg s^{-1}, makes it among the brightest high-redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time delayed variability to follow about 25 days after a primary flare, with flux about a factor 1.5 less. Two large gamma-ray flares of PKS 1830-211 have been detected by the LAT in the considered period and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the gamma rays flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program indicate a hard spectrum and with no significant correlation of X-ray flux with the gamma-ray variability. The spectral energy distribution can be modeled with inverse Compton scattering of thermal photons from the dusty torus. The implications of the LAT data in terms of variability, the lack of evident delayed flare events, and different radio and gamma-ray flux ratios are discussed. Microlensing effects, absorption, size and location of the emitting regions, the complex mass distribution of the system, an energy-dependent inner structure of the source, and flux suppression by the lens galaxy for one image path may be considered as hypotheses for understanding our results.Comment: 14 pages, 6 figures, 2 tables. Accepted by the The Astrophysical Journal. Corresponding authors: S. Ciprini (ASI ASDC & INAF OAR, Rome, Italy), S. Buson (INAF Padova & Univ. of Padova, Padova, Italy), J. Finke (NRL, Washington, DC, USA), F. D'Ammando (INAF IRA, Bologna, Italy