Automatic landmarking for building biological shape models

We present a new method for automatic landmark extraction from the contours of biological specimens. Our ultimate goal is to enable automatic identification of biological specimens in photographs and drawings held in a database. We propose to use active appearance models for visual indexing of both photographs and drawings. Automatic landmark extraction will assist us in building the models. We describe the results of using our method on drawings and photographs of examples of diatoms, and present an active shape model built using automatically extracted data

On the Role of Higher Twist in Polarized Deep Inelastic Scattering

The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron structure functions $g_1^N(x, Q^2)$ are extracted in a model independent way from experimental data on $g_1^N$ and found to be non-negligible. It is shown that the NLO QCD polarized parton densities determined from the data on g1, including higher twist effects, are in good agreement with those found earlier from our analysis of the data on g1/F1 and A1 where higher twist effects are negligible. On the contrary, the LO QCD polarized parton densities obtained from the data on g1, including higher twist, differ significantly from our previous results.Comment: 18 pages, latex, 6 figures, final version which will be published in Phys. Rev. D, fig. 5 is changed, misprints in Table 2 are remove

Insights on Fission Products behaviour in Nuclear Severe Accident Conditions by X-ray Absorption Spectroscopy

International audienceMany research programs have been carried out aiming to understand the fission products behaviour during a Nuclear Severe Accident. Most of these programs used highly radioactive irradiated nuclear fuel, which requires complex instrumentation. Moreover, the radioactive character of samples hinders an accurate chemical characterisation. In order to overcome these difficulties, SIMFUEL stand out as an alternative to perform complementary tests. A sample made of UO$_2$ doped with 11 fission products was submitted to an annealing test up to 1973 K in reducing atmosphere. The sample was characterized before and after the annealing test using SEM-EDS and XAS at the MARS beam-line, SOLEIL Synchrotron. It was found that the overall behaviour of several fission products (such as Mo, Ba, Pd and Ru) was similar to that observed experimentally in irradiated fuels and consistent with thermodynamic estimations. The experimental approach presented in this work has allowed obtaining information on chemical phases evolution under nuclear severe accident conditions, that are yet difficult to obtain using irradiated nuclear fuel samples

Baseline groundwater chemistry : the Lower Greensand aquifer of South East England

This report details the hydrogeochemistry of a broad suite of inorganic and organic analytes in groundwater from the Lower Greensand aquifer of south-east England. The study aims to establish the groundwater baseline chemical compositions, particularly of those analytes that are and could be associated with Onshore Oil and Gas (OOG) activities, in order to facilitate distinction between current compositions and any new industrial contamination from such activities. Analytes of particular interest in this context include indicators of salinity, indicators of redox conditions, dissolved gases including carbon dioxide (CO2) and methane (CH4), naturally-occurring radioactive materials (NORM) and organic compounds including volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Much of the exposed unconfined aquifer is oxic in nature, with groundwater pH controlled by the sporadic presence of calcite within the aquifer matrix. Concentrations of a number of dissolved ions increase along the regional flow path, including Ca, HCO3, Mg, K, Sr, F, Al, As, Mn, Cu, Ni, Fe and Mn. The unconfined aquifer is susceptible to a number of anthropogenic impacts. These include diffuse pollution from agricultural activities (indicated by elevated concentrations of nitrate in groundwater across the northern half of the study area), and mobilisation of metals by acidic rainfall recharge in parts of the aquifer where acid-buffering carbonate minerals are absent. Dissolved organic carbon content of the Lower Greensand groundwater is typically low, with an upper baseline concentration of 4.6 mg/L. Anthropogenic organic chemicals detected as part of this study included chloroform, trichloroethene and chlorodibromomethane, but concentrations detected are orders of magnitude below the drinking-water standard for these compounds and not a cause for concern. Dissolved CH4 concentrations in the Lower Greensand aquifer are generally low; most samples in the investigation area contained 300 μg/L were observed (up to 461 μg/L)

Baseline groundwater chemistry: the Pennine Coal Measures of the East Midlands and South Yorkshire

This report details the hydrogeochemistry of a suite of inorganic and organic analytes in groundwater for the Pennine Coal Measures aquifer of the East Midlands and South Yorkshire region. The study aims to establish the groundwater baseline chemical compositions, particularly of those analytes that are and could be associated with onshore oil and gas (OOG) activities, in order to facilitate distinction between current compositions and any new industrial contamination from such activities. Analytes of special interest in this context include indicators of salinity, redox conditions, dissolved gases including carbon dioxide (CO2) and methane (CH4), and organic compounds including volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). The following assessment has been derived solely from Environment Agency Water Quality Archive (WIMS) data. The Pennine Coal Measures aquifer is a complex, multi-layered secondary aquifer, comprising sandstones interbedded with low-permeability mudstones and coal seams. Groundwater flow is influenced regionally both by natural structural features and a lasting legacy of coal-mining activities. Groundwater quality in the aquifer is characterised by a large range of pH values (4.9–9.3) and commonly high dissolved-solids contents (SEC up to 6030 μS/cm). Conditions in the aquifer appear reducing to strongly reducing, with typically elevated Fe and NH4, and in places high Mn, alongside low concentrations of NO3, U and V. Both dissolved Fe and SO4 are found in high concentrations in groundwater in a number of locations and are considered to be derived from the now-flooded mine workings and the dissolution of oxidised pyrite. Organic-carbon content in the groundwater has an upper baseline concentration of 5.22 mg/L for dissolved organic carbon (DOC), and 6.45 mg/L for total organic carbon (TOC). Sources for organic carbon within the aquifer may be partly anthropogenic (industry, urban, agricultural) in origin, but are in large part derived from the abundant coal seams present within the aquifer. No dissolved gas (CH4, CO2) analyses were available from the EA WIMS data, but previous studies have identified up to 9 mg/L of dissolved methane in groundwater from the area. Only a small number of PAH and VOC compounds were detected within the EA WIMS dataset, typically each of low concentrations (<1 μg/L), but with some evidence of localised pollution from anthropogenic sources

Baseline groundwater chemistry : the Sherwood Sandstone aquifer of the East Midlands and South Yorkshire

This report details the hydrogeochemistry of a broad suite of inorganic and organic analytes in groundwater from the Sherwood Sandstone aquifer of the East Midlands and South Yorkshire. The study aims to establish the groundwater baseline chemical compositions, particularly of those analytes that are and could be associated with onshore oil and gas (OOG) activities, in order to facilitate distinction between current compositions and any new industrial contamination from such activities. Analytes of particular interest in this context include indicators of salinity, indicators of redox conditions, dissolved gases including CO2 and CH4, naturally-occurring radioactive materials and organic compounds including volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Groundwater from the Sherwood Sandstone aquifer of the region shows a range of chemical compositions resulting from inputs of modern atmospheric and surface pollution from varying sources, superimposed on natural water-rock interactions. Natural reactions are dominated by carbonate equilibrium, redox reactions, gypsum/anhydrite dissolution and time-dependent silicatemineral reaction. The Sherwood Sandstone crops out in the East Midlands but further northwards into Yorkshire, the aquifer in places becomes confined or semi-confined by overlying Quaternary superficial silts and clays. The Sherwood Sandstone dips gently eastwards and becomes confined by the poorly-permeable marls and mudstones of the Mercia Mudstone Group (MMG). At outcrop, the groundwater is young and oxic with evidence of inputs of pollutants including NO3, SO4 and Cl and possibly of Br, Cu, Pb and Zn from urban, industrial (including mine drainage) and agricultural sources. Small quantities of PAHs, pesticides and solvents are detected occasionally in the unconfined aquifer. Further north into Yorkshire, the aquifer is oxic in parts but becomes anoxic in places with superficial cover and with increasing depth. The reducing groundwaters in this zone have low NO3 concentrations and increased concentrations of Fe and Mn. Increased concentrations of Co, Sb and V may be associated with release of Fe and Mn into solution under mildly reducing conditions, either within the sandstone or from the superficial deposits. As the Sherwood Sandstone becomes confined eastwards by the MMG, downgradient chemical changes are controlled by maintained equilibrium with calcite and dolomite, dissolution of gypsum or anhydrite and development of reducing conditions. These controls see progressive increases downgradient in concentrations of SO4, and slight increases in concentrations of Fe, Mn, NH4 and Mo. High concentrations especially of SO4 and NH4 in the north-east area around Goole are speculatively associated with facies changes in the sandstone further north, the groundwater possibly interacting with a greater proportion of sulphate minerals and clays. In the deep confined aquifer, conditions are insufficiently reducing for SO4 reduction to be quantitatively important. Under the reducing conditions in the MMG-confined aquifer and to some extent in the areas covered by superficial deposits, small quantities of dissolved CH4 are detected (up to 120 µg/L in this study). Concentrations are low in the unconfined sections of the aquifer. Concentrations in the confined aquifer are relatively low because of a paucity of organic carbon in the aquifer for significant methanogenesis to take place. No other hydrocarbon or PAH, pesticide or solvent compounds were detected in the confined aquifer. Detection of a small quantity of chloroform at one location in the shallow confined aquifer is anomalous and difficult to explain. The groundwater shows a well-established downgradient increase in residence time as it passes beneath the MMG. Limited radiocarbon dating in this study supports previous conclusions that confined groundwater close to the western edge of the MMG has model ages of around 2000– 10,000 years, increasing to late Pleistocene (19,000 years) along the flow path at its eastern edge. The study reiterates that within the aquifer, fresh groundwater extends to around 20 km away from the outcrop and to depths of some 400–500 m below ground. The confined aquifer may be especially vulnerable to pollution from any future deep hydrocarbon exploration activities and would require careful monitoring