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See detailDerivation of Auroral Conductances from IMAGE FUV
Immel, T. J.; Mende, S. B.; Frey, H. U. et al

Conference (2001, May 01)

Auroral emissions are observed in 3 separate Far-Ultraviolet (FUV) wavelength regimes by IMAGE. The Wideband Imaging Camera (WIC) is sensitive mainly to N[SUB]2[/SUB] LBH and N I emissions in the 140-190 ... [more ▼]

Auroral emissions are observed in 3 separate Far-Ultraviolet (FUV) wavelength regimes by IMAGE. The Wideband Imaging Camera (WIC) is sensitive mainly to N[SUB]2[/SUB] LBH and N I emissions in the 140-190-nm range, while the Spectrographic Imager (SI) spectrally separates the OI 135.6-nm emission and Doppler shifted hydrogen emissions of the proton aurora at 121.8 nm. The brightness of the N[SUB]2[/SUB] LBH and OI 135.6-nm emissions depend in part on the spectrum and total energy flux of incoming electrons, and on the height-density profile of the respective species, and O[SUB]2[/SUB]. Due mainly to these atmospheric factors, the ratio of the N[SUB]2[/SUB] and OI emissions depends strongly on the characteristic energy of precipitating electrons which, once estimated, can in turn be used to calculate the total energy flux. The proton aurora generates secondary electrons, which excite additional emissions of N[SUB]2[/SUB] and OI. It is not possible to absolutely determine either the total proton energy flux or the characteristic proton energy (<E[SUB]p[/SUB]>) with a single proton imaging channel. However, the proton-induced N[SUB]2[/SUB] and OI emissions depend mainly on the total proton energy flux, so reasonable estimates of <E[SUB]p[/SUB]> can be used in the calculation of proton energy input. Ground-based or in-situ observations of proton energies can help in this determination. With accurate corrections for N[SUB]2[/SUB] and OI airglow emissions, and formulae such as those provided by Robinson et al. [1987], IMAGE FUV can provide global maps of height-integrated conductivity (conductance) in the auroral oval. It is also possible to examine the degree to which the proton aurora contributes to enhanced conductance on a global scale. The promise of providing these conductances using IMAGE's real-time capabilities will be discussed. Robinson, R. M., R. R. Vondrak, K. Miller, T. Dabbs, and D. Hardy, On Calculating Ionospheric Conductances from the Flux and Energy of Precipitating Electrons, J. Geophys. Res., 92, 2566, 1987. [less ▲]

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See detailDerivation of cochlear cells from pathological or isogenic human iPSCs for modeling hereditary hearing loss
Czajkowski, Amandine ULg; Grobarczyk, Benjamin; Hanon, Kevin ULg et al

Poster (2016, May)

Alström Syndrome (AS) is a human autosomal recessive genetic disorder characterized by numerous clinical symptoms including deafness. AS is caused by mutations in the ALMS1 gene encoding for ALMS1 protein ... [more ▼]

Alström Syndrome (AS) is a human autosomal recessive genetic disorder characterized by numerous clinical symptoms including deafness. AS is caused by mutations in the ALMS1 gene encoding for ALMS1 protein expressed at the basal body and implicated in ciliogenesis, cell cycle and proliferation (Jagger et al., 2011; Zulato et al., 2011 & Shenje et al., 2014). We are interesting in understanding the unknown mechanisms involving this protein in the genetic deafness of AS patients. To develop a model as closer as possible to the human pathology, we are using human induced pluripotent stem cells (hiPSCs) generated from fibroblasts of healthy and AS patients. Using a stepwise protocol, we demonstrated that healthy hiPSCs (waiting for isogenic hiPSCs) can generate a population of cells with gene and protein expression patterns consistent with the ones of otic progenitor cells (OSCs). At this differentiation stage, we observed some proliferation and apoptotic defects between healthy and AS cells. When human OSCs are co-cultured with mouse feeder cells, they are able to differentiate into hair cells (HCs). We successfully differentiated AS hiPSCs generated from AS patients into HCs. We are currently confirming gene expression pattern and testing HCs functionality.  To exclude patient linked epigenetics and differentiation defects, we are correcting the genomic mutation in the AS hiPSCs to generate isogenic hiPSCs using the CRIPSR/Cas9 system. Thanks to the isogenic hiPSCs we will be able to confirm that these defects are well due to the ALMS1 mutation. [less ▲]

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See detailDerivation of flow and transport parameters from outcropping sediments of the Neogene aquifer, Belgium
Rogiers, Bart; Beerten, K.; Smeekens, T. et al

in Geologica Belgica (2013), 16(3), 129-147

Centimetre-scale saturated hydraulic conductivities (K) are derived from air permeability measurements on a selection of outcrops of the Neogene aquifer in the Campine area, Belgium. Outcrop sediments are ... [more ▼]

Centimetre-scale saturated hydraulic conductivities (K) are derived from air permeability measurements on a selection of outcrops of the Neogene aquifer in the Campine area, Belgium. Outcrop sediments are of Miocene to Quaternary age and have a marine to continental origin. Grain size analyses for the same outcrops and corresponding K predictions using previously developed models are also presented. We discuss outcrop hydrogeological properties and quantify the heterogeneity within the outcrops in detail using geostatistical variography. Moreover, outcrop-scale K values, their anisotropy and dispersivities are numerically calculated as a means to upscale such small-scale measurements to a larger scale commensurate with the scale of flow and transport modelling. By studying the small-scale variability as observed in outcrops, we gain crucial understanding of the larger-scale behaviour of the corresponding hydrogeological units within the Neogene aquifer, the most important groundwater reservoir of Flanders. The results of this study will equally improve conceptual hydrogeological model building and parameterization. [less ▲]

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See detailDerivation of high resolution TSM data by merging geostationary and polar-orbiting satellite data in the North Sea.
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Vanhellemont, Quinten et al

Conference (2013, September 09)

There is a need for high resolution ocean colour data, both in space and time, for a better assessment of the variability of these data and their influence in the environment, specially at shallow areas ... [more ▼]

There is a need for high resolution ocean colour data, both in space and time, for a better assessment of the variability of these data and their influence in the environment, specially at shallow areas where factors as tides and wind play a role in their dynamics. High spatial resolution is achieved by polar-orbiting satellites, but at a low temporal resolution. The opposite is true for geostationary satellites. In order to exploit the complementary nature of geostationary and polar data, a merging methodology has been developed to obtain a unique estimate of the North Sea Total Suspended Matter (TSM). The largest difficulty in developing a merging methodology is the correct estimation of the error covariance matrix, which can be specially complex for variables like TSM. In this work, the error covariance is not parametrized a priori using an analytical expression, but expressed using a truncated spatial EOF basis calculated by analysing MODIS data using DINEOF (Data INterpolating Empirical Orthogonal Functions). This EOF basis represents more realistically the complex variability of the TSM data sets than the parametric covariance used in most optimal interpolation applications. This EOF basis is subsequently used to merge MODIS and SEVIRI TSM data using an optimal interpolation approach. Results for the North Sea 2009 TSM will be shown, demonstrating the possibilities of this technique. The influence of including variables like winds or tides in the analysis, through multivariate approaches, will be assessed. [less ▲]

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See detailDerivation of high-resolution ocean surface fields for regional and coastal models
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; He, R. et al

Conference (2005)

Coastal ocean circulation models need high-resolution input fields, such as winds, sea surface height and heat fluxes, to represent the variability of coastal systems. Atmosphere model outputs and ... [more ▼]

Coastal ocean circulation models need high-resolution input fields, such as winds, sea surface height and heat fluxes, to represent the variability of coastal systems. Atmosphere model outputs and satellite data are usually used. However, atmosphere models are usually too coarse and do not represent the high variability of coastal systems, and satellite data do not present a complete coverage, mainly due to cloudiness. In situ observations can accurately represent the complex temporal variability of coastal regions, but usually their spatial coverage is far from optimal. Several products derived from atmosphere models, satellite images and in situ observations are prepared to use as high-resolution input fields suitable for coastal models. An optimally interpolated (OI) wind field has been realized by merging atmosphere model winds, satellite-derived winds (from quikSCAT) and in situ buoy measurements. Other fields, such as geostrophic currents, are derived from Sea Surface Height anomaly obtained from the Topex/Poseidon, Jason, ERS 1/2 and Envisat altimeter product of the CLS center, plus a MICOM mean dynamic topography. Sea Surface Temperature (SST) is also needed to correct surface heat fluxes, but satellite SST is often gappy due to clouds. Two different approaches are investigated in order to obtain complete fields, one using OI and the other using Empirical Orthogonal Functions (EOF) for the reconstruction of missing data. The EOF-based method can reconstruct different variables together, such as SST and surface chlorophyll, by using the correlation between them. This multi-variate approach is used here, and compared to the mono-variate OI product. [less ▲]

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See detailDerivation of optimal scroll compressor wrap for minimization of leakage losses
Bell, Ian ULg; Groll, Eckhard; Braun, James et al

in International Compressor Engineering Conference at Purdue, July 16-19, 2012 (2012, July)

The scroll wraps of a scroll compressor play a very important role in the compressor’s efficiency due to their impact on leakage and leakage irreversibilities. In this work, a short summary of the scroll ... [more ▼]

The scroll wraps of a scroll compressor play a very important role in the compressor’s efficiency due to their impact on leakage and leakage irreversibilities. In this work, a short summary of the scroll compressor geometry is presented. Using the geometry of the scroll wraps, an optimal scroll wrap geometry is derived for a given set of constraints on compressor displacement, scroll wrap thickness and volume ratio. This optimal scroll wrap geometry can be used as a starting point for further optimization in a detailed compressor model that includes the effects of mechanical losses. [less ▲]

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See detailDerivation of the 1.0-0.9 Ga ferro-potassic A-type granitoids of southern Norway by extreme differentiation from basic magmas
Vander Auwera, Jacqueline ULg; Bogaerts, Michel; Liégeois, Jean-Paul ULg et al

in Precambrian Research (2003), 124(2-4), 107-148

Major and trace elements, Sr and Nd isotopic data as well as mineral compositions are presented for a selection of the 1.0 - 0.9 ferro-potassic A-type granitoids (Bessefjellet, Rustfjellet ... [more ▼]

Major and trace elements, Sr and Nd isotopic data as well as mineral compositions are presented for a selection of the 1.0 - 0.9 ferro-potassic A-type granitoids (Bessefjellet, Rustfjellet, Verhuskjerringi, Valle, Holum, Svöfjell, Handeland-Tveit, Åseral, Lyngdal gabbronorites) that occur close to the Mandal-Ustaoset Line of southern Norway. These hornblende biotite granitoids (HBG) define an extensive differentiation trend ranging from gabbronorites (50 wt % SiO2) to granites (77 wt % SiO2). This trend is interpreted as resulting from extreme fractional crystallization of several basaltic magma batches with similar major and trace elements compositions. At 930 Ma, the HBG suite displays a narrower range in ISr (0.7027 - 0.7056) than in Nd(t) (+1.97 down to -4.90) suggesting some assimilation of a Rb-depleted lower crust (AFC process) or/and source variability. An age of 929 ± 47 Ma is given by a Rb-Sr isochron on the Holum granite (Sri = 0.7046 ±0.0006, MSWD = 1.7). Geothermobarometers indicate a low pressure of emplacement (1.3-2.7 kbar) and an oxygen fugacity close to NNO. High liquidus temperatures are given by the apatite saturation thermometer (1005°C to 1054 °C) and are in agreement with results from other studies. The basaltic parent magmas of the HBG suite are partial melts of an hydrous mafic, potassic source lying either in the lithospheric upper mantle or in the mafic lower crust derived from it. This contrasts with the 930 Ma anorthosite-mangerite-charnockite suite (AMC) of the Rogaland Province for which a depleted lower crustal anhydrous gabbronoritic source has been indicated. The present data imply the penecontemporaneous melting of two contrasting sources in southern Norway. The source duality could result from an increasing degree of metamorphism (amphibolite to granulite) from East to West, an horizontal stratification of the lower crust or from the stratification of the lithosphere (melting of the lower crust or upper mantle). It may also indicate that the AMC and HBG suites formed in two distinct crustal segments. The linear alignment of the HBG suite along the Mandal-Ustaoset shear zone suggests that a linear uprise of the asthenosphere, following a lithospheric delamination under this structure, could be the vector of the mantle heat. [less ▲]

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See detailDerivation of the Consistent Osmotic Virial Equation and Its Application to Aqueous Poly(ethylene glycol)-Dextran Two-Phase Systems
Doebert, Frank; Pfennig, Andreas ULg; Stumpf, Matthias

in Macromolecules (1995), 28(23), 7860-7868

Detailed reference viewed: 19 (1 ULg)
See detailDerivation of the Maxwell-Boltzmann distribution by discrete modeling
Pfleger, M; Wallek, T; Pfennig, Andreas ULg

Conference (2012)

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See detailDerivation of the rotational frequency of massive stars from seismic studies
Aerts, C.; Scuflaire, Richard ULg; Thoul, Anne ULg

in Stellar Rotation. 215 (2004)

In this contribution we review the current status of the determination of the rotational frequency in non-radially pulsating B stars, i.e. beta Cep stars and slowly pulsating B stars. Considerable ... [more ▼]

In this contribution we review the current status of the determination of the rotational frequency in non-radially pulsating B stars, i.e. beta Cep stars and slowly pulsating B stars. Considerable progress is currently being made in the understanding of the non-radial oscillations of main-sequence B Stars by means of high-temporal, high-spatial resolution spectroscopic time series. This has led to the detection of frequency multiplets, which are interpreted as rotationally splitted non-radial modes and which allow an accurate determination of the surface rotational frequency in some stars. We outline how our future goal, i.e. the derivation of the internal rotation frequency, can be achieved. [less ▲]

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See detailDerivatives of 2,5- and 3,5-disubstituted anilines, their preparation and use
Dorwald, F. Z.; Hansen, J. B.; Mogensen, J. P. et al

Patent (1999)

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See detailDerivatization of Amino Acids in Human Plasma for Quantitation by Comprehensive Two Dimensional Gas Chromatography Time of Flight Mass Spectrometry
Mc Gaw, Elizabeth; Eppe, Gauthier ULg; Lowenthal, Mark et al

in ASMS Conference on Mass Spectrometry and Allied Topics (2009)

Detailed reference viewed: 34 (3 ULg)
See detailDérive
Mouton, Charles ULg

Book published by Dricot (2006)

Detailed reference viewed: 14 (2 ULg)
See detailDerive, A mathematical assistant for your personal computer (3e édition)
Manfroid, Jean ULg

in Ciel et Terre (1990), 106

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See detailDerived Categories for Functional Analysis
Prosmans, Fabienne ULg

in Publications of the Research Institute for Mathematical Sciences (2000), 36(1), 19-83

We study the homological algebra of the category of locally convex topological vector spaces from the point of view of derived categories.

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See detailDerived Limits in Quasi-Abelian Categories
Prosmans, Fabienne ULg

in Bulletin de la Société Royale des Sciences de Liège (1999), 68(5-6), 335-401

We study the derived functors of projective limit functors in quasi-abelian categories.

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See detailDerived Projective Limits of Topological Abelian Groups
Prosmans, Fabienne ULg

in Journal of Functional Analysis (1999), 162(1), 135-177

We prove that the category of topological Abelian groups is quasi-Abelian. Using results about derived projective limits in quasi-Abelian categories, we study exactness properties of the projective limit ... [more ▼]

We prove that the category of topological Abelian groups is quasi-Abelian. Using results about derived projective limits in quasi-Abelian categories, we study exactness properties of the projective limit functor in the category of topological Abelian groups. [less ▲]

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See detailLa dérivée schwarzienne
Bair, Jacques ULg; Haesbroeck, Gentiane ULg

in Mathématique et Pédagogie (1996), 108

Dans cette note est introduit le concept de dérivée schwarzienne pour une fonction réelle univariée. Diverses propriétés et applications sont également proposées.

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