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See detailErratum: Multipartite-entanglement monotones and polynomial invariants
Eltschka, Christopher; Bastin, Thierry ULg; Osterloh, Andreas et al

in Physical Review. A (2012), 85

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See detailErratum: SN 2007uy − metamorphosis of an aspheric Type Ib explosion
Roy, Rupak ULg

in Monthly Notices of the Royal Astronomical Society (2014)

The supernovae (SNe) of Type Ibc are rare and the detailed characteristics of these explosions have been studied only for a few events. Unlike Type II SNe, the progenitors of Type Ibc have never been ... [more ▼]

The supernovae (SNe) of Type Ibc are rare and the detailed characteristics of these explosions have been studied only for a few events. Unlike Type II SNe, the progenitors of Type Ibc have never been detected in pre-explosion images. So, to understand the nature of their progenitors and the characteristics of the explosions, investigation of proximate events are necessary. Here we present the results of multi-wavelength observations of Type Ib \sn\ in the nearby ($\sim$ 29.7 Mpc) galaxy NGC 2770. Analysis of the photometric observations revealed this explosion as an energetic event with peak absolute $R$ band magnitude $-18.5\pm0.16$, which is about one mag brighter than the mean value ($-17.6\pm0.6$) derived for well observed Type Ibc events. The SN is highly extinguished, \ebv\ = 0.63$\pm$0.15 mag, mainly due to foreground material present in the host galaxy. From optical light curve modeling we determine that about 0.3 \msun\ radioactive $^{56}$Ni is produced and roughly 4.4 \msun\ material is ejected during this explosion with liberated energy $\sim 15\times10^{51}$ erg, indicating the event to be an energetic one. Through optical spectroscopy, we have noticed a clear aspheric evolution of several line forming regions, but no dependency of asymmetry is seen on the distribution of $^{56}$Ni inside the ejecta. The SN shock interaction with the circumburst material (CSM) is clearly noticeable in radio follow-up, presenting a Synchrotron Self Absorption (SSA) dominated light curve with a contribution of Free Free Absorption (FFA) during the early phases. Assuming a Wolf-Rayet (WR) star, with wind velocity $\ga 10^3 {\rm km~s}^{-1}$, as a progenitor, we derive a lower limit to the mass loss rate inferred from the radio data as $\dot{M} \ga 2.4\times10^{-5}$ \msun\,~yr$^{-1}$, which is consistent with the results obtained for other Type Ibc SNe bright at radio frequencies. [less ▲]

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See detailErratum: The XMM Large-Scale Structure survey: an initial sample of galaxy groups and clusters to a redshift z < 0.6
Willis, J. P.; Pacaud, F.; Valtchanov, I. et al

in Monthly Notices of the Royal Astronomical Society (2005), 364

We present X-ray and optical spectroscopic observations of twelve galaxy groups and clusters identified within the XMM Large-Scale Structure (LSS) survey. Groups and clusters are selected as extended X ... [more ▼]

We present X-ray and optical spectroscopic observations of twelve galaxy groups and clusters identified within the XMM Large-Scale Structure (LSS) survey. Groups and clusters are selected as extended X-ray sources from a 3.5 deg2 XMM image mosaic above a flux limit 8e-15 ergs/s/cm2 in the [0.5-2] keV energy band. Deep BVRI images and multi-object spectroscopy confirm each source as a galaxy concentration located within the redshift interval 0.29<z<0.56. We combine line-of-sight velocity dispersions with the X-ray properties of each structure computed from a two-dimensional surface brightness model and a single temperature fit to the XMM spectral data. The resulting distribution of X-ray luminosity, temperature and velocity dispersion indicate that the XMM-LSS survey is detecting low-mass clusters and galaxy groups to redshifts z < 0.6. Confirmed systems display little or no evidence for X-ray luminosity evolution at a given X-ray temperature compared to lower redshift X-ray group and cluster samples. A more complete understanding of these trends will be possible with the compilation of a statistically complete sample of galaxy groups and clusters anticipated within the continuing XMM-LSS survey. [less ▲]

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See detailErratum: VLT + UVES spectroscopy of the low-ionization intrinsic absorber in SDSS J001130.56+005550.7
Hutsemekers, Damien ULg; Hall, Patrick; Brinkmann, J.

in Astronomy and Astrophysics (2004), 422

Not Available

Detailed reference viewed: 5 (2 ULg)
See detailL'erreur totale pour le transfert de méthodes
Rozet, Eric ULg

Conference (2010)

Detailed reference viewed: 36 (3 ULg)
See detailL'erreur totale pour le transfert de méthodes
Rozet, Eric ULg

Conference (2009)

Detailed reference viewed: 12 (2 ULg)
See detailL'erreur, matière première de l'apprentissage d'une langue
Defays, Jean-Marc ULg

Conference given outside the academic context (2008)

Detailed reference viewed: 29 (2 ULg)
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See detailErreurs de catégorie et erreur de catégoriser
Leclercq, Bruno ULg

Conference (2000, May 06)

Detailed reference viewed: 10 (0 ULg)
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See detailErreurs de classification dans les tables de contingence
Magis, David ULg

Scientific conference (2003, December)

Detailed reference viewed: 6 (1 ULg)
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See detailErreurs de désignations d'Etoiles Ap ou Am
Renson, Pierre ULg

in Bulletin d'Information du Centre de Données Stellaires (1988), 34

A table of erroneous designations which appeared in the literature for Ap and Am stars is given. The number of stars erroneously designated at least once is of the order of 2% of the total number of known ... [more ▼]

A table of erroneous designations which appeared in the literature for Ap and Am stars is given. The number of stars erroneously designated at least once is of the order of 2% of the total number of known or probable Ap and Am stars. [less ▲]

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See detailLes erreurs humaines en anesthésie
De Keyser, Véronique ULg; Nyssen, Anne-Sophie ULg

in Travail Humain (Le) (1993), 56(2-3), 243-266

Human errors in anesthesia - with due respect to the French-speaking tradition, human error is studied in field work, here in anesthesia. The authors specify the social context, compare the process of ... [more ▼]

Human errors in anesthesia - with due respect to the French-speaking tradition, human error is studied in field work, here in anesthesia. The authors specify the social context, compare the process of anesthesia to a continuous process, present a cognitive analyse of the task, emphasizing temporal characteristics and cognitive demands regarding the cognitive aspects of human behavior. Referring to the dictinction made by Hollnagel (1991) between reliability, robustness and adaptiveness of the system (man and machine), they present and analyse some human errors which reveal the importance of variation elements and the dynamic dimension of the environment. Influenced by Time Psychology, they postulate the existence of different systems of temporal reference and of external synchronizers connected to these systems, which would allow an individual to adaptively respond to the demands for synchronization in the face of events and actions whose evolutions cannot be calibrated in clock time. Inadequate systems of temporal reference and the absence of synchronizers can make this adaptation to the evolution and the dynamicity of the environment fail. The prevention integrates different measures (technological, ergonomic, social, organizational, of expertise development, etc.) and relies on collection and in-depth analysis of human error. This paper is dedicated to J. Leplat. [less ▲]

Detailed reference viewed: 77 (9 ULg)
See detailError analysis of a high-resolution physical model of the Mediterranean Sea
Vandenbulcke, Luc ULg; Barth, Alexander ULg; Alvera Azcarate, Aïda ULg et al

Conference (2007)

We analyze the errors that are inevitably associated to hydrodynamic models, in a realistic case. The error of the GHER model in the Mediterranean Sea has already been studied in e.g. Beckers et al. (2000 ... [more ▼]

We analyze the errors that are inevitably associated to hydrodynamic models, in a realistic case. The error of the GHER model in the Mediterranean Sea has already been studied in e.g. Beckers et al. (2000) by comparing it with other primitive equation models, or in Alvera (2004) by comparing the model with observations and with the climatology, using usual statistical methods and also wavelet decompositions. In this study, we rather study the sensitivity of the model to various variables using an ensemble of models. We chose a relatively high resolution, 1/16°, corresponding to the resolution now used in operational OGCMs covering the Mediterranean, such as the MFS system (http://www.bo.ingv.it/mfs). We explain how we generated an ensemble of model simulations, where various more-or-less well known inputs are allowed to vary according to the uncertainty affecting them. Statistics calculated on this ensemble are, in fact, the response of the non-linear hydrodynamic system to errors on the forcing terms. When those statistics are calculated at a certain timestep, they allow us to provide a spatial analysis of the model error; statistics calculated over the time dimension will show whether errors are intensified by the system, or rather disappear. The model error is interesting as such. However, it can also be used for different purposes. For example, it allows using data assimilation techniques without needing the usual assumptions of reduced-rank Kalman Filters. It also allows studying the sensitivity of coupled model (biological, oil spill, search-and-rescue, …) to physical forcings. [less ▲]

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See detailError analysis of generalized-alpha Lie group time integration methods for constrained mechanical systems
Arnold, Martin; Bruls, Olivier ULg; Cardona, Alberto

in Numerische Mathematik (in press)

Generalized-alpha methods are very popular in structural dynamics. They are methods of Newmark type and combine favourable stability properties with second order convergence for unconstrained second order ... [more ▼]

Generalized-alpha methods are very popular in structural dynamics. They are methods of Newmark type and combine favourable stability properties with second order convergence for unconstrained second order systems in linear spaces. Recently, they were extended to constrained systems in flexible multibody dynamics that have a configuration space with Lie group structure. In the present paper, the convergence of these Lie group methods is analysed by a coupled one-step error recursion for differential and algebraic solution components. It is shown that spurious oscillations in the transient phase result from order reduction that may be avoided by a perturbation of starting values or by index reduction. Numerical tests for a benchmark problem from the literature illustrate the results of the theoretical investigations. [less ▲]

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See detailError assessment of sea surface temperature satellite data relative to in situ data: effect of spatial and temporal coverage
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Troupin, Charles ULg et al

Conference (2010, April 30)

A comparison between satellite and in situ sea surface temperature (SST) data in the Western Mediterranean Sea in 1999 is shown. The aim of this study is to better understand the differences between these ... [more ▼]

A comparison between satellite and in situ sea surface temperature (SST) data in the Western Mediterranean Sea in 1999 is shown. The aim of this study is to better understand the differences between these two data sets, in order to compute merged maps of SST using satellite and in situ data. When merging temperature from different platforms, it is crucial to take the expected RMS error of the observations into account and to correct for possible biases. Different in situ data sensors and platforms (CTD, XBT, drifter, etc) are available for the comparison, each with specificities in the nature of the measurement (accuracy and precision of the measures), and with different spatial and temporal distributions. A comparison with satellite data needs to take these factors into account. Statistics about the differences due to the hour of the day, the month of the year, the type of sensor/ platform used and the spatial distribution is therefore realised through a combination of error measures, diagrams and statistical hypothesis testing. The data used are Advanced Very High Resolution Radiometer (AVHRR) SST day-time and night-time satellite data, and in situ temperature data from various databases (World Ocean Database’05, Coriolis, Medar/Medatlas and ICES). [less ▲]

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See detailError convergence of some classical high order curl-conforming finite elements
Geuzaine, Christophe ULg; Dular, Patrick ULg; Meys, B. et al

in Proceedings of the 4th International Workshop on Electric and Magnetic Fields, EMF 1998 (1998)

Detailed reference viewed: 8 (0 ULg)
See detailAn error decomposition method: Application to mediterranean sst simulations assessment
Ben Bouallegue, Z.; Alvera Azcarate, Aïda ULg; Beckers, Jean-Marie ULg

Conference (2004, September)

Fields composed of daily simulations provided by an OGCM of the Mediterranean Sea are compared to weekly satellite observations. The method used is inspired of the object-oriented verification procedure ... [more ▼]

Fields composed of daily simulations provided by an OGCM of the Mediterranean Sea are compared to weekly satellite observations. The method used is inspired of the object-oriented verification procedure introduced in meteorological forecast assessment by Ebert and al. 2000. The Error Decomposition Method presented here aims to identify error sources. The method is carried out within the framework of the MFSTEP hindcasts. The MFSTEP project is an international scientific collaboration program which aims to create an operational forecasting system for the Mediterranean Sea. The simulations provided at the basin scale are 10 days forecasting fields in a 3-D ocean. The hydrodynamic model primitive equations are combined with the data assimilation scheme SOFA applied every week. The set of data used for the comparison are weekly SST satellite observations and means of seven daily MFSTEP simulations (analyzed fields) for the equivalent weeks. The original simulation is transformed until the total squared difference between the observed and hindcast fields is minimized. Successively, a new combination of seven consecutive daily simulations is produced, the new SST field is displaced horizontally and the bias suppressed. This allows a decomposition of the total error in 4 parts: a temporal shift error, a position error, an intensity error and a pattern error. This last element is the remaining error after simulation field transformation and corresponds to the unexplained error. The method is applied at different restricted areas of the Mediterranean basin. The predominant displacements in time and in space minimizing error are discussed through the physical processes taking places at each location. More over, ratio between the different error components is analysed in term of scale effect: the role of the application domain size is pointed out. Finally, the seasonal impact on the different results is commented. [less ▲]

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See detailError detection: A study in anaesthesia
Nyssen, Anne-Sophie ULg; Blavier, Adelaïde ULg

in Ergonomics (2006), 49(5-6), 517-525

Although error has been shown as the main cause of accidents in complex systems, little attention has been paid to error detection. However, reducing the consequences of error depends largely on error ... [more ▼]

Although error has been shown as the main cause of accidents in complex systems, little attention has been paid to error detection. However, reducing the consequences of error depends largely on error detection. The goal of this paper is to synthesize the existing scientific knowledge on error detection, mostly based on studies conducted in laboratory or self reporting and to further knowledge through the analysis of a corpus of cases collected in a complex system, anaesthesia. By doing this, this paper is better able to describe how this knowledge can be used to improve understanding of error detection modes. An anaesthesia accident reporting system developed and organized at two Belgian University Hospitals was used in order to collect information about the error detection patterns. Results show that detection of errors principally occurred through the standard check (routine monitoring of the environment). Significant relationships were found between the type of error and the error detection mode, and between the type of error and the training level of the anaesthetist who committed the error. [less ▲]

Detailed reference viewed: 83 (36 ULg)