889 research outputs found
Implementation of a method to determine sub-nanomolar concentrations of iron in seawater and its application to the study of marine iron biogeochemistry at the ocean-shelf interface
No full textThe aim of this study was to improve our understanding of the marine iron cycle using a newly implemented technique to measure dissolved iron in seawater. The setting up of a flow-injection analyser with chemiluminescence detection (FIACL) for Fe(II) proved to be non-trivial. Extensive work was undertaken to solve problems relating to our limited level of understanding of the CL reaction, and the variable behaviour of the resins prepared to preconcentrate iron. An analyser for Fe(II)+(III) was optimised, and careful assessment of data demonstrated the high quality of the information interpreted in this study, from the Celtic Sea shelf edge (Northeast Atlantic), and from the North Scotia Ridge (Southern Ocean).The distribution of iron at the Celtic Sea shelf edge was examined, and was used to provide a conceptual framework for future studies. Dissolved Fe (< 0.4 µm) concentrations were measured in samples from nine vertical profiles taken across the continental slope (160 – 2950 m water depth). Dissolved iron concentrations varied between 0.2 and 5.4 nM, and the resulting detailed section showed evidence of a range of processes influencing the iron distributions. The presence of elevated levels of dissolved Fe near the seafloor was consistent with release of Fe from in situ particulate organic matter remineralisation at two upper slope stations, and possibly of pore water release upon resuspension on shelf. Lateral transport of dissolved iron was evident in an intermediate nepheloid layer and its advection along an isopycnal. Surface waters at the shelf break also showed evidence of vertical mixing of deeper iron-rich waters. The data also suggest some degree of stabilisation of relatively high concentrations of iron, presumably through ligand association or as colloids. The possibility of iron limitation of phytoplankton at the shelf edge was not ruled out despite obvious depletion of nitrate. This study supports the view that export of dissolved iron laterally to the ocean’s interior from shelf and coastal zones may have important implications for the global
budget of oceanic iron.A set of surface samples collected on a survey between the Falkland Islands and South Georgia were analysed for total dissolvable iron. Results suggested a source of benthic iron near South Georgia. A shift in photo-physiology of phytoplankton towards South Georgia was probably influenced by the transition from iron-limited to iron-replete populations. These results therefore strongly support the hypothesis that South Georgia may be a "pulse-point" of iron to high-nutrient low-chlorophyll waters
kinnewig/dealii: Hanging Nodes for Nedelec v1.0.1
No full text<p>#Algorithmic Realization: Solution to the Sign Conflict Problem for Hanging Nodes on Hp-Hexahedral Nédélec Elements</p>
<p>This Release contains the implementation of an algorithmic solution to the sign conflict problem
for hanging nodes on hp-hexahedral Nédélec elements. The starting point for this work was deal.II 9.5.2.</p>
<p>#Overview
The sign conflict problem arises for Nédélec elements, as Nédélec elements are oriented.
These elements are widely used in electromagnetic simulations and other scientific computing applications.
Especially in the presence of hanging faces, one has to take special care of the orientation.
The algorithmic realization presented here addresses the orientation problem in the presence of hanging faces
and provides a robust solution.</p>
kinnewig/dealii: Hanging Nodes for Nedelec v1.0.0
No full text<h1>Algorithmic Realization: Solution to the Sign Conflict Problem for Hanging Nodes on Hp-Hexahedral Nédélec Elements</h1>
<p>This Release contains the implementation of an algorithmic solution to the sign conflict problem
for hanging nodes on hp-hexahedral Nédélec elements. The starting point for this work was deal.II 9.5.2.</p>
<h1>Overview</h1>
<p>The sign conflict problem arises for Nédélec elements, as Nédélec elements are oriented.
These elements are widely used in electromagnetic simulations and other scientific computing applications.
Especially in the presence of hanging faces, one has to take special care of the orientation.
The algorithmic realization presented here addresses the orientation problem in the presence of hanging faces
and provides a robust solution.</p>
Dispersive properties of high order nedelec/edge element approximation of the time-harmonic Maxwell equations
No full textThe dispersive behaviour of high-order Næ#169;dæ#169;lec element approximation of the time harmonic Maxwell equations at a prescribed temporal frequency ω on tensor-product meshes of size h is analysed. A simple argument is presented, showing that the discrete dispersion relation may be expressed in terms of that for the approximation of the scalar Helmholtz equation in one dimension. An explicit form for the one-dimensional dispersion relation is given, valid for arbitrary order of approximation. Explicit expressions for the leading term in the error in the regimes where ωh is small, showing that the dispersion relation is accurate to order 2p for a pth-order method; and in the high-wavenumber limit where 1«ωh, showing that in this case the error reduces at a super-exponential rate once the order of approximation exceeds a certain threshold, which is given explicitly
sj-docx-1-evp-10.1177_14747049231212356 - Supplemental material for Predicting Moffitt's Developmental Taxonomy of Antisocial Behavior Using Life History Theory: A Partial Test of the Evolutionary Taxonomy
No full textSupplemental material, sj-docx-1-evp-10.1177_14747049231212356 for Predicting Moffitt's Developmental Taxonomy of Antisocial Behavior Using Life History Theory: A Partial Test of the Evolutionary Taxonomy by Joseph L. Nedelec and Francesco DiRienzo in Evolutionary Psychology</p
Duration of Residence in the Same Dwelling. A Test of Measurement using Electricity Utility Company Records
No full textCourgeau Daniel, Nedelec V., Empereur-Bissonnet P. Duration of Residence in the Same Dwelling. A Test of Measurement using Electricity Utility Company Records. In: Population, an English selection, 12ᵉ année, n°1, 2000. pp. 335-342
« Mon corps, mes droits ! » L’avortement menacé ?| Brunet et Guyard-Nedelec (dir.)
No full textLaurence Brunet et Alexandrine Guyard-Nedelec (dir.), « Mon corps, mes droits ! » L’avortement menacé ? Panorama socio-juridique : France, Europe, Etats-Unis, Paris : Mare et Martin, 2018, 206 p. Compte rendu par Laurie Marguet (Université Paris-Est Créteil, centre MIL) L’ouvrage qu’il nous est donné de rapporter est un ouvrage collectif composé de plusieurs contributions relatives à la question de l’avortement dans différents pays occidentaux ainsi qu’à l’échelle européenne. Il entend prése..
Numerical simulations for type II superconductors: Finite Element Method for the time-dependent Ginzburg-Landau equations
No full textSuperconductivity was discovered in 1911 and since then it has become indispensable in a wide range of fields. It is often accompanied by strong magnetic fields which can do away with the superconducting properties of the material. This process is described by the Ginzburg-Landau theory of superconductivity. In this report, this theory is discussed at length. The result is a system of two coupled, time-dependent partial differential equations that can be solved using numerical methods. A nite element method is constructed using standard Lagrangian and curl-conforming Nedelec elements. Numerical simulations were performed with Lagrangian and Nedelec elements in COMSOL and MATLAB respectively. Using Lagrangian elements delivers flawed results. Using Nedelec elements should improve these results but so far only parts of the problem have successfully been solved using these elements
Supplemental material for The Psychometrics of the Mini-K: Evidence From Two College Samples
No full textSupplemental material, for The Psychometrics of the Mini-K: Evidence From Two College Samples by George B. Richardson, Ching-Chen Chen, Chia-Liang Dai, Michael D. Brubaker, and Joseph L. Nedelec in Evolutionary Psychology</p
Nedelec, P.: Assimilation of SCIAMACHY total column CO observations; Global and regional analysis of data impact
No full text[1] Carbon monoxide (CO) total column observations from the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) on board Envisat-1 are assimilated into the Global Modeling and Assimilation Office constituent assimilation system for the period 1 April to 20 December 2004. The impact of the assimilation on CO distribution is evaluated using independent surface flask observations from the National Oceanic and Atmospheric Administration (NOAA)/ESRL global cooperative air sampling network and Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) in situ CO profiles. Assimilation of SCIAMACHY data improves agreement of CO assimilation with both of these data sets on both global and regional scales compared to the free-running model. Regional comparisons with MOZAIC profiles made in western Europe, the northeastern United States, and the Arabian Peninsula show improvements at all three locations in the free troposphere and into the boundary layer over Arabia and the northeastern United States. Comparisons with NOAA Earth System Research Laboratory data improve at about two thirds of the surface observation sites. The systematic model errors related to the uncertainty of CO surface sources and the chemistry of CO losses are investigated through experiments with increased surface CO emissions over the Arabian Peninsula and/or globally reduced hydroxyl radical (OH) concentrations. Both model changes decrease mean CO errors at all altitudes in comparison to MOZAIC data over Dubai and Abu Dhabi. In contrast, errors in the assimilated CO are reduced by the increased emissions for pressures !800 hPa and by the reduced OH for pressures 600 hPa. Our analysis suggests that CO emissions over Dubai in 2004 are more than double those in the 1998 emissions inventory
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