Gravity field and internal structure of Mercury from MESSENGER

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR(2) = 0.353 ± 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(m)/C = 0.452 ± 0.035. A model for Mercury's radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.     

Product differentiation,labelling and quality approach: Developments and stakes in the French shellfish market

Abstract

France is one of the world's top producers of oysters and mussels by aquaculture with 140 000 tonnes of oysters, 60 000 tonnes of mussels and an ex‐farm turnover accounting to 350 million US$ in 1996. The French market is by far the largest in Europe for oysters and is supplied entirely by domestic production, with very little external trade. Conversely, the French market for mussels is a very competitive one, widely open to imports. Given the evolution of market conditions due to the development of supermarkets, to the competition of new value‐added products and to the modification of consumer habits, French oyster and mussel producers have begun to implement various strategies of product differentiation and quality approach. These numerous strategies, which are built on geographical origin, process of production or marketing promotion may induce confusion in the consumer's mind. A typology of these strategies has been drawn in order to clarify the situation and to assess their sustainability. Since any quality approach has a counterpart in terms of production costs, an enquiry has been carried out at the level of supermarkets in order to assess the price the buyers are ready to pay for labelled oysters and mussels. The results of this study show important variations according to the locality of the supermarkets, especially with regard to the distance to the coast and the size of the town. Contractual relationships between producers and supermarkets as well as better production organization prove to be important perquisites to ensure successful product differentiation and quality approaches.     

Antiviral Sulfoquinovosyldiacylglycerols (SQDGs) from the Brazilian Brown Seaweed Sargassum vulgare

Total lipids from the Brazilian brown seaweed Sargassum vulgare were extracted with chloroform/methanol 2:1 and 1:2 (v/v) at room temperature. After performing Folch partition of the crude lipid extract, the lipids recovered from the Folch lower layer were fractionated on a silica gel column eluted with chloroform, acetone and methanol. The fraction eluted with methanol, presented a strong orcinol-positive band characteristic of the presence of sulfatides when examined by TLC. This fraction was then purified by two successive silica gel column chromatography giving rise to fractions F4I86 and F4II90 that exhibited strong activity against herpes simplex virus type 1 and 2. The chemical structures present in both fractions were elucidated by ESI-MS and ¹H/¹³C NMR analysis HSQC fingerprints based on their tandem–MS behavior as sulfoquinovosildiacylglycerols (SQDGs). The main SQDG present in both fractions and responsible for the anti-herpes activity observed was identified as 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-d-quinovopyranosyl)-glycerol.     

Plant and animal endemism in the eastern Andean slope: challenges to conservation

Background

The Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants) and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients) with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioner's scale (1:250,000-1:1,000,000), based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas.

Results

We found that sizes of endemic species distributions ranged widely (< 20 km² to > 200,000 km²) across the study area. Bird and mammal endemic species richness was greatest within a narrow 2500-3000 m elevation band along the length of the Andes Mountains. Endemic amphibian richness was highest at 1000-1500 m elevation and concentrated in the southern half of the study area. Geographical distribution of plant endemism was highly taxon-dependent. Irreplaceable areas, defined as locations with the highest number of species with narrow ranges, overlapped slightly with areas of high endemism, yet generally exhibited unique patterns across the study area by species group. We found that many endemic species and ecological systems are lacking national-level protection; a third of endemic species have distributions completely outside of national protected areas. Protected areas cover only 20% of areas of high endemism and 20% of irreplaceable areas. Almost 40% of the 91 ecological systems are in serious need of protection (= < 2% of their ranges protected).

Conclusions

We identify for the first time, areas of high endemic species concentrations and high irreplaceability that have only been roughly indicated in the past at the continental scale. We conclude that new complementary protected areas are needed to safeguard these endemics and ecosystems. An expansion in protected areas will be challenged by geographically isolated micro-endemics, varied endemic patterns among taxa, increasing deforestation, resource extraction, and changes in climate. Relying on pre-existing collections, publically accessible datasets and tools, this working framework is exportable to other regions plagued by incomplete conservation data.