On the remote sensing of oceanic and atmospheric convection in the Greenland Sea by synthetic aperture radar

In this paper we discuss characteristic properties of radar signatures of oceanic and atmospheric convection features in the Greenland Sea. If the water surface is clean (no surface films or ice coverage), oceanic and atmospheric features can become visible in radar images via a modulation of the surface roughness, and their radar signatures can be very similar. For an unambiguous interpretation and for the retrieval of quantitative information on current and wind variations from radar imagery with such signatures, theoretical models of current and wind phenomena and their radar imaging mechanisms must be utilized. We demonstrate this approach with the analysis of some synthetic aperture radar (SAR) images acquired by the satellites ERS-2 and RADARSAT-1. In once case, an ERS-2 SAR image an a RADARSAT-1 ScanSAR image exhibit pronounced cell-like signatures with length scales on the order of 10-20 km and modulation depths of about 5-6 dB and 9-10 dB, respectively. Simulations with a numerical SAR imagaing model and various input current and wind fields reveal that the signatures in both images can be expained consistently by wind variations on the order of±2.5 ms, but not by surface current variations on realistic orders of magnitude. Accordingly, the observed features must be atmospheric convection cells. This is confirmed by visible typical cloud patterns in a NOAA AVHRR image of the test scenario. In another case, the presence of an oceanic convective chimney is obvious from in situ data, but no signatures of it are visible in an ERS-2 SAR image. We show by numerical simulations with an oceanic convection model and our SAR imaging model that this is consistent with theoretical predictions, since the current gradients associated with the observed chimney are not sufficiently strong to give rise to significant signatures in an ERS-2 SAR image under the given conditions. Further model results indicate that it should be generally difficult to observe oceanic convection features in the Greenland Sea with ERS-2 or RADARSAT-1 SAR, since their signatures resulting from pure wave-current interaction will be too weak to become visible in the noisy SAR images in most cases. This situation will improve with the availability of future high-resolution SARs such as RADARSAT-2 SAR in fine resolution mode (2004) and TerraSAR-X (2005) which will offer significantly reduced speckle noise fluctuations at comparable spatial resolutions and thus a much better visibility of small image variations on spatial scales on the order of a few hundred meters

Deep structure of the Tyrrhenian basin from 2-D joint refraction and reflection travel-time tomography of wide angle seismic data

European Geosciences Union General Assembly 22-27 April 2012, Vienna, Austria.-- 1 pageLocated between Italy, Corsica, Sardinia and Sicily the Tyrrhenian Sea is a Neogene back-arc basin formed by continental extension related to the southeastward rollback of the subducting Ionian oceanic plate. This basin is an ideal place to study the evolution of extension process. The basin structure displays different amount of extension along its length, from the low-extension episodes of continental rifting in the northern areas to break up and exhumation of the mantle in the deepest part of the basin. Here there also seems to be evidence of extension-associated volcanism. In order to study the nature of the crust and the 4D evolution of the Tyrrhenian basin, a survey to collect multichannel (MCS) and wide-angle seismic (WAS) data was carried out into the framework of the MEDOC project in 2010 with the coordination of 2 research vessels, the R/V Sarmiento de Gamboa and the R/V Urania. During the experiment a total of 17 MCS lines and 5 WAS lines were acquired, with 125 deployments of both Ocean Bottom Hydrophones and Seismometers (OBH/S) and simultaneous land recordings in Corsica, Sardinia and Italy. In this work we present modeling results along two WAS lines that cross the central and deepest area of the basin. The models, which are obtained by joint refraction and reflection travel-time tomography, unveil the seismic structure of the crust and uppermost mantle and the geometry of the Moho boundary. The data selected for the inversion are arrival times of phases refracted through the crust and upper mantle (Pg and Pn phases), and those reflected at the Moho boundary (PmP phases). A statistical uncertainty analysis has been also performed to account for the inverted model parameters uncertainty (velocity values and Moho geometry). The seismic structure of both models reveals a significant lateral variation of the velocity gradient that has allowed defining various different crustal domains. In the western side of the profiles, the models show a progressive transition between a 23 km-thick continental crust, and a thinned, and apparently magmatically-intruded crust with a well-defined Moho boundary. Thinning is more pronounced in the central, deepest part of the basin, where the abrupt thinning coincides with the absence of PmP reflections and, in turn, with that of a well-developed Moho boundary. In this area, the velocity model indicates that the basement is mainly made of exhumed upper mantle rocks such as those described in the ODP Leg 107 in 1990. Finally, in the central part of the basin where the exhumed mantle domain is larger we find three low-velocity anomalies attributed to the extension-related magmatismPeer Reviewe

Parasitism, host behavior, and invasive species

Animal behavior and parasitism are inextricable linked. In many cases, host behavior can affect what parasites are encountered. In other cases, parasites can manipulate the behavior of the host in an attempt to maximize their own transmission. These long-standing interactions are now further complicated by species movement around the globe. The list of introduced species that have become invasive includes parasites that have adapted to new hosts in areas of introduction, as well as invasive hosts that alter the association between existing parasite–host assemblages. Researchers have documented differences in rates of parasitism and in the consequences of parasite infection between invasive and native hosts, and sometimes these differences are a result of behavioral differences, either pre-existing host behaviors or host behaviors that are altered as a consequence of infection. Parasites have been shown to mediate interactions between native and invasive hosts; occasionally, these parasites determine the outcome of invasions. The effects on native species can be severe, and to that end, interactions between invasive species, parasites, and behavior have ramifications for conservation biology

Dietary Intakes and Nutritional Status of Mother-Child (6-23 Months Old) Pair Targeted through the "Organic Residual Products for Biofortified Foods for Africa Project" in Rural Area in Senegal

Background: Despite micronutrient supplementation and food fortification strategies carried out for decades, micronutrient deficiencies remain prevalent among children under 5 years old in rural area in Senegal. The OR4FOOD project was implemented as a preventive and long-term approach to reduce malnutrition through biofortification. Objective: We aimed to assess the baseline dietary intakes and nutritional status of the mother-child (6-23 months old) pair in a rural community in Senegal. Methods: Dietary intakes were assessed using dietary recall questionnaires and weight food records. All foods and beverages consumed from waking to bedtime were quantified, and nutrient intakes were calculated. The nutritional status was measured by anthropometry. Results: Results showed that 77.2% of children had low dietary diversity score. Only 18% of them received an appropriate complementary feeding according to the minimum acceptable diet. Cereals and legumes were among the most consumed food groups, whereas orange-fleshed sweet potato (OFSP) and animal food products were rarely consumed. Median dietary intakes of iron, zinc, and vitamin A were lower than the recommended dietary allowances. Acute malnutrition and stunting affected 14.6% and 16.9% of children, respectively. Overall, 20.8% of mothers were underweighted, and overweight/obesity affected 23.1% of them. Conclusion: Malnutrition remains prevalent in rural areas of Senegal and affects both mothers and children. Furthermore, their nutrient requirements were not covered by the diet. Millet and cowpea being widely consumed, optimizing their iron and zinc content through biofortification and the introduction of OFSP might improve micronutrient intakes and would be promising strategies to prevent child malnutrition