Impact of natural (waves and currents) and anthropogenic (trawl) resuspension on the export of particulate matter to the open ocean: Application to the Gulf of Lion (NW Mediterranean)

Accepted manuscript version. Published version available at https://doi.org/10.1016/j.csr.2008.02.002. Licensed CC BY-NC-ND 4.0.Modern sediment deposits on continental margins form a vast reservoir of particulate matter that is regularly affected by resuspension processes. Resuspension by bottom trawling on shelves with strong fishing activity can modify the scale of natural disturbance by waves and currents. Recent field data show that the impact of bottom trawls on fine sediment resuspension per unit surface is comparable with that of the largest storms. We assessed the impact of both natural and anthropogenic processes on the dispersal of riverborne particles and shelf sediments on the Gulf of Lion shelf. We performed realistic numerical simulations of resuspension and transport forced by currents and waves or by a fleet of bottom trawlers. Simulations were conducted for a 16-month period (January 1998–April 1999) to characterise the seasonal variability. The sediment dynamics takes into account bed armoring, ripple geometry and the cohesive and non-cohesive characteristics of the sediments. Essential but uncertain parameters (clay content, erosion fluxes and critical shear stress for cohesive sediment) were set with existing data. Resuspension by waves and currents was controlled by shear stress, whereas resuspension by trawls was controlled by density and distribution of the bottom trawler fleet. Natural resuspension by waves and currents mostly occurred during short seasonal episodes, and was concentrated on the inner shelf. Trawling-induced resuspension, in contrast, occurred regularly throughout the year and was concentrated on the outer shelf. The total annual erosion by trawls (5.6×106 t y−1, t for metric tonnes) was four orders of magnitude lower than the erosion induced by waves and currents (35.3×109 t y−1). However the net resuspension (erosion/deposition budget) for trawling (0.4×106 t y−1) was only one order of magnitude lower than that for waves and currents (9.2×106 t y−1). Off-shelf export concerned the finest fraction of the sediment (clays and fine silts) and took place primarily at the southwestern end of the Gulf. Off-shelf transport was favoured during the winter 1999 by a very intense episode of dense shelf water cascading. Export of sediment resuspended by trawls (0.4×106 t y−1) was one order of magnitude lower than export associated with natural resuspension (8.5×106 t y−1). Trawling-induced resuspension is thought to represent one-third of the total export of suspended sediment from the shelf. A simulation combining both resuspension processes reveals no significant changes in resuspension and export rates compared with the sum of each individual process, suggesting the absence of interference between both processes.</p

The triangular nasal notch sign in patients with Crohn&#039;s disease treated with tumor necrosis factor inhibitors

Tumor necrosis factor (TNF) inhibitors are used to treat a range of chronic inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease and psoriasis. Some of the cutaneous side effects of these drugs are well documented, such as infections, skin carcinomas, palmoplantar and skinfold pustulosis, psoriasis-like or eczema-like lesions. We are not aware of TNF inhibitor-induced nasal lesions in the literature. We report a case series demonstrating a specific pattern of cicatricial nasal fissure (triangular nasal notch) following nasal dermatitis episodes in patients treated with TNF inhibitors. This article is protected by copyright. All rights reserved

The contamination of the surface of Vesta by impacts and the delivery of the dark material

The Dawn spacecraft observed the presence of dark material, which in turn proved to be associated with OH and H-rich material, on the surface of Vesta. The source of this dark material has been identified with the low albedo asteroids, but it is still a matter of debate whether the delivery of the dark material is associated with a few large impact events, to micrometeorites or to the continuous, secular flux of impactors on Vesta. The continuous flux scenario predicts that a significant fraction of the exogenous material accreted by Vesta should be due to non-dark impactors likely analogous to ordinary chondrites, which instead represent only a minor contaminant in the HED meteorites. We explored the continuous flux scenario and its implications for the composition of the vestan regolith, taking advantage of the data from the Dawn mission and the HED meteorites. We used our model to show that the stochastic events scenario and the micrometeoritic flux scenario are natural consequences of the continuous flux scenario. We then used the model to estimate the amounts of dark and hydroxylate materials delivered on Vesta since the LHB and we showed how our results match well with the values estimated by the Dawn mission. We used our model to assess the amount of Fe and siderophile elements that the continuous flux of impactors would mix in the vestan regolith: concerning the siderophile elements, we focused our attention on the role of Ni. The results are in agreement with the data available on the Fe and Ni content of the HED meteorites and can be used as a reference frame in future studies of the data from the Dawn mission and of the HED meteorites. Our model cannot yet provide an answer to the fate of the missing non-carbonaceous contaminants, but we discuss possible reasons for this discrepancy.Comment: 31 pages, 7 figures, 4 tables. Accepted for publication on the journal ICARUS, "Dark and Bright Materials on Vesta" special issu

Low doses of a neonicotinoid insecticide modify pheromone response thresholds of central but not peripheral olfactory neurons in a pest insect

Insect pest management relies mainly on neurotoxic insecticides, including neonicotinoids, leaving residues in the environment. There is now evidence that low doses of insecticides can have positive effects on pest insects by enhancing various life traits. Because pest insects often rely on sex pheromones for reproduction, and olfactory synaptic transmission is cholinergic, neonicotinoid residues could modify chemical communication. We recently showed that treatments with different sublethal doses of clothianidin could either enhance or decrease behavioural sex pheromone responses in the male moth, Agrotis ipsilon. We investigated now effects of the behaviourally active clothianidin doses on the sensitivity of the peripheral and central olfactory system. We show with extracellular recordings that both tested clothianidin doses do not influence pheromone responses in olfactory receptor neurons. Similarly, in vivo optical imaging does not reveal any changes in glomerular response intensities to the sex pheromone after clothianidin treatments. The sensitivity of intracellularly recorded antennal lobe output neurons, however, is upregulated by a lethal dose 20 times and downregulated by a dose 10 times lower than the lethal dose 0. This correlates with the changes of behavioural responses after clothianidin treatment and suggests the antennal lobe as neural substrate involved in clothianidin-induced behavioural changes

Optical properties and morphology of InAs ∕ InP (113)B surface quantum dots

We report on long-wavelength photoluminescence(PL) emission at room temperature from self-organized InAssurfacequantum dotsgrown by gas-source molecular beam epitaxy on a GaInAsP∕InP (113)B substrate. The influence of arsenic pressure conditions during growth on the PL emission of surfacequantum dots is detailed as well as oxide/contamination layer formation after growth. Experimental results are in good agreement with six-band k⋅p theory in the envelope function approximation.This work was supported by the SANDIE European Network of Excellence

Olivine or Impact Melt: Nature of the "Orange" Material on Vesta from Dawn

NASA's Dawn mission observed a great variety of colored terrains on asteroid (4) Vesta during its survey with the Framing Camera (FC). Here we present a detailed study of the orange material on Vesta, which was first observed in color ratio images obtained by the FC and presents a red spectral slope. The orange material deposits can be classified into three types, a) diffuse ejecta deposited by recent medium-size impact craters (such as Oppia), b) lobate patches with well-defined edges, and c) ejecta rays from fresh-looking impact craters. The location of the orange diffuse ejecta from Oppia corresponds to the olivine spot nicknamed "Leslie feature" first identified by Gaffey (1997) from ground-based spectral observations. The distribution of the orange material in the FC mosaic is concentrated on the equatorial region and almost exclusively outside the Rheasilvia basin. Our in-depth analysis of the composition of this material uses complementary observations from FC, the visible and infrared spectrometer (VIR), and the Gamma Ray and Neutron Detector (GRaND). Combining the interpretations from the topography, geomorphology, color and spectral parameters, and elemental abundances, the most probable analog for the orange material on Vesta is impact melt