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Maurice-Van Eijndhoven M.H.T.,Animal Breeding and Genomics Center | Maurice-Van Eijndhoven M.H.T.,Wageningen University | Maurice-Van Eijndhoven M.H.T.,Wageningen UR Livestock Research | Soyeurt H.,University of Liège | And 3 more authors.
Animal | Year: 2013

The aim of this study was to investigate the accuracy to predict detailed fatty acid (FA) composition of bovine milk by mid-infrared spectrometry, for a cattle population that partly differed in terms of country, breed and methodology used to measure actual FA composition compared with the calibration data set. Calibration equations for predicting FA composition using mid-infrared spectrometry were developed in the European project RobustMilk and based on 1236 milk samples from multiple cattle breeds from Ireland, Scotland and the Walloon Region of Belgium. The validation data set contained 190 milk samples from cows in the Netherlands across four breeds: Dutch Friesian, Meuse-Rhine-Yssel, Groningen White Headed (GWH) and Jersey (JER). The FA measurements were performed using gas-liquid partition chromatography (GC) as the gold standard. Some FAs and groups of FAs were not considered because of differences in definition, as the capillary column of the GC was not the same as used to develop the calibration equations. Differences in performance of the calibration equations between breeds were mainly found by evaluating the standard error of validation and the average prediction error. In general, for the GWH breed the smallest differences were found between predicted and reference GC values and least variation in prediction errors, whereas for JER the largest differences were found between predicted and reference GC values and most variation in prediction errors. For the individual FAs 4:0, 6:0, 8:0, 10:0, 12:0, 14:0 and 16:0 and the groups' saturated FAs, short-chain FAs and medium-chain FAs, predictions assessed for all breeds together were highly accurate (validation R 2 > 0.80) with limited bias. For the individual FAs cis-14:1, cis-16:1 and 18:0, the calibration equations were moderately accurate (R 2 in the range of 0.60 to 0.80) and for the individual FA 17:0 predictions were less accurate (R 2 < 0.60) with considerable bias. FA concentrations in the validation data set of our study were generally higher than those in the calibration data. This difference in the range of FA concentrations, mainly due to breed differences in our study, can cause lower accuracy. In conclusion, the RobustMilk calibration equations can be used to predict most FAs in milk from the four breeds in the Netherlands with only a minor loss of accuracy. © The Animal Consortium 2012.


Alvera-Azcarate A.,University of Liège | Alvera-Azcarate A.,National Fund for Scientific Research | Sirjacobs D.,Boulevard du Rectorat 27 | Barth A.,University of Liège | And 2 more authors.
Remote Sensing of Environment | Year: 2012

Satellite data sets often contain outliers (i.e., anomalous values with respect to the surrounding pixels), mostly due to undetected clouds and rain or to atmospheric and land contamination. A methodology to detect outliers in satellite data sets is presented. The approach uses a truncated Empirical Orthogonal Function (EOF) basis. The information rejected by this EOF basis is used to identify suspect data. A proximity test and a local median test are also performed, and a weighted sum of these three tests is used to accurately detect outliers in a data set. Most satellite data undergo automated quality-check analyses. The approach presented exploits the spatial coherence of the geophysical fields, therefore detecting outliers that would otherwise pass such checks. The methodology is applied to infrared sea surface temperature (SST), microwave SST and chlorophyll-a concentration data over different domains, to show the applicability of the technique to a range of variables and temporal and spatial scales. A series of sensitivity tests and validation with independent data are also conducted. © 2011 Elsevier Inc.


Canor T.,University of Liège | Canor T.,National Fund for Scientific Research | Blaise N.,University of Liège | Denoel V.,University of Liège
Journal of Sound and Vibration | Year: 2012

The use of normal modes of vibration in the analysis of structures with non-proportional damping reduces the size of the resulting set of governing equations, but does not decouple them. A common practice consists in decoupling the equations by disregarding the off-diagonal elements in the modal damping matrix. Recently, an approximation based on an asymptotic expansion of the modal transfer matrix has been proposed in a deterministic framework to partially account for off-diagonal terms, but still with a set of uncoupled equations. This paper aims at extending this method in a stochastic context. First the mathematical background is introduced and the method is illustrated with a simple example. Then its relevance is demonstrated within the context of the structural analysis of a large and realistic structure. © 2012 Elsevier Ltd. All rights reserved.


Vandenplas J.,University of Liège | Vandenplas J.,National Fund for Scientific Research | Gengler N.,University of Liège | Gengler N.,National Fund for Scientific Research
Journal of Dairy Science | Year: 2012

The aim of this research was to compare different Bayesian procedures to integrate information from outside a given evaluation system, hereafter called external information, and in this context estimated breeding values (EBV), into this genetic evaluation, hereafter called internal evaluation, and to improve the Bayesian procedures to assess their potential to combine information from diverse sources. The 2 improvements were based on approximations of prior mean and variance. The first version of modified Bayesian evaluation considers all animals as animals associated with external information. For animals that have no external information (i.e., internal animals), external information is predicted from available external information. Thereby, propagation of this external information through the whole pedigree is allowed. Furthermore, the prediction of external information for internal animals allows large simplifications of the computational burden during setup and solving of mixed model equations. However, double counting among external animals (i.e., animals associated with available external information) is not avoided. Double counting concerns multiple considerations of contributions due to relationships by integration of external EBV for related external animals and is taken into account by the second version of modified Bayesian evaluation. This version includes the estimation of double counting before integration of external information. To test the improvements, 2 dairy cattle populations were simulated across 5 generations. Milk production for the first lactation for each female was simulated in both populations. Internal females were randomly mated with internal males and 50 external males. Results for 100 replicates showed that rank correlations among Bayesian EBV and EBV based on the joint use of external and internal data were very close to 1 for both external and internal animals if all internal and external animals were associated with external information. The respective correlations for the internal evaluation were equal to 0.54 and 0.95 if no external information was integrated. If double counting was avoided, mean squared error, expressed as a percentage of the internal mean squared error, was close to zero for both external and internal animals. However, computational demands increased when double counting was avoided. Finally, the improved Bayesian procedures have the potential to be applied for integrating external EBV, or even genomic breeding values following some additional assumptions, into routine genetic evaluations to evaluate animals more reliably. © 2012 American Dairy Science Association.


Heeren A.,Catholic University of Louvain | Heeren A.,National Fund for Scientific Research | Reese H.E.,Massachusetts General Hospital | McNally R.J.,Harvard University | Philippot P.,Catholic University of Louvain
Behaviour Research and Therapy | Year: 2012

Social phobics exhibit an attentional bias for threat in probe detection and probe discrimination paradigms. Attention training programs, in which probes always replace nonthreatening cues, reduce attentional bias for threat and self-reported social anxiety. However, researchers have seldom included behavioral measures of anxiety reduction, and have never taken physiological measures of anxiety reduction. In the present study, we trained individuals with generalized social phobia (n = 57) to attend to threat cues (attend to threat), to attend to positive cues (attend to positive), or to alternately attend to both (control condition). We assessed not only self-reported social anxiety, but also behavioral and physiological measures of social anxiety. Participants trained to attend to nonthreatening cues demonstrated significantly greater reductions in self-reported, behavioral, and physiological measures of anxiety than did participants from the attend to threat and control conditions. © 2011 Elsevier Ltd.


Canor T.,University of Liège | Canor T.,National Fund for Scientific Research | Denoel V.,University of Liège
International Journal for Numerical Methods in Engineering | Year: 2013

Probabilistic theories aim at describing the properties of systems subjected to random excitations by means of statistical characteristics such as the probability density function ψ (pdf). The time evolution of the pdf of the response of a randomly excited deterministic system is commonly described with the transient Fokker-Planck-Kolmogorov (FPK) equation. The FPK equation is a conservation equation of a hypothetical or abstract fluid, which models the transport of probability. This paper presents a generalized formalism for the resolution of the transient FPK equation by using the well-known mesh-free Lagrangian method, smoothed particle hydrodynamics).Numerical implementation shows notable advantages of this method in an unbounded state space: (1) the conservation of total probability in the state space is explicitly written; (2) no artifact is required to manage far-field boundary conditions; (3) the positivity of the pdf is ensured; and (4) the extension to higher dimensions is straightforward.Furthermore, thanks to the moving particles, this method is adapted for a large kind of initial conditions, even slightly dispersed distributions. The FPK equation is solved without any a priori knowledge of the stationary distribution, just a precise representation of the initial distribution is required. © 2013 John Wiley & Sons, Ltd.


Soyeurt H.,University of Liège | Soyeurt H.,National Fund for Scientific Research | Misztal I.,University of Georgia | Gengler N.,University of Liège | Gengler N.,National Fund for Scientific Research
Journal of Dairy Science | Year: 2010

The aim of this study was to estimate the genetic parameters of the mid-infrared (MIR) milk spectrum represented by 1,060 data points per sample. The dimensionality of traits was reduced by principal components analysis. Therefore, 46 principal components describing 99.03% of the phenotypic variability were used to create 46 new traits. Variance components were estimated using canonical transformation. Heritability ranged from 0 to 0.35. Twenty-five out of 46 studied traits showed a permanent environment variance greater than genetic variance. Eight traits showed heritability greater than 0.10. Variances of original spectral traits were obtained by back transformation. Heritabilities for each spectral data points ranged from 0.003 to 0.42. In particular, 3 MIR regions showing moderate to high heritability estimates were of potential genetic interest. Heritabilities for specific wave numbers, linked with common milk traits (e.g., lipids, lactose), were similar to those estimated for these traits. This research confirms the genetic variability of the MIR milk spectrum and, therefore, the genetic variation of milk components. The objective of this study was to better understand the genetics of milk composition and, maybe in the future, to select animals to improve milk quality. © 2010 American Dairy Science Association.


Heeren A.,Catholic University of Louvain | Heeren A.,National Fund for Scientific Research | Lievens L.,Catholic University of Louvain | Philippot P.,National Fund for Scientific Research
Journal of Anxiety Disorders | Year: 2011

Social phobics exhibit an attentional bias for threat in probe detection paradigms. Attention training, whereby probes always replace non-threat in a display presenting both threat and non-threat, reduces attentional bias for threat and social anxiety. However, it remains unclear whether therapeutic benefits result from learning to disengage attention from threat or learning to orient attention towards non-threat. In this experiment, social phobics were randomly assigned to one of four training conditions: (1) disengagement from threat, (2) engagement towards non-threat, (3) disengagement from threat and re-engagement towards non-threat, and (4) a control condition. Effects were examined on subjective and behavioral responses to a subsequent stressor. Data revealed that training to disengage from threat reduces behavioral indices of anxiety. Engagement towards non-threat faces did not have effects in itself. These results support that the difficulty in disengaging attention from threat is a critical process in maintenance of the disorder. © 2011 Elsevier Ltd.


Alpan A.,Free University of Colombia | Maryn Y.,Sint Jan General Hospital | Kacha A.,Free University of Colombia | Grenez F.,Free University of Colombia | And 2 more authors.
Speech Communication | Year: 2011

The objective is to analyse vocal dysperiodicities in connected speech produced by dysphonic speakers. The analysis involves a variogram-based method that enables tracking instantaneous vocal dysperiodicities. The dysperiodicity trace is summarized by means of the signal-to-dysperiodicity ratio, which has been shown to correlate strongly with the perceived degree of hoarseness of the speaker. Previously, this method has been evaluated on small corpora only. In this article, analyses have been carried out on two corpora comprising over 250 and 700 speakers. This has enabled carrying out multi-frequency band and multi-cue analyses without risking overfitting. The analysis results are compared to the cepstral peak prominence, which is a popular cue that indirectly summarizes vocal dysperiodicities frame-wise. A perceptual rating has been available for the first corpus whereas speakers in the second corpus have been categorized as normal or pathological only. For the first corpus, results show that the correlation with perceptual scores increases statistically significantly for multi-band analysis compared to conventional full-band analysis. Also, combining the cepstral peak prominence with the low-frequency band signal-to-dysperiodicity ratio statistically significantly increases their combined correlation with perceptual scores. The signal-to-dysperiodicity ratios of the two corpora have been separately submitted to principal component analysis. The results show that the first two principal components are interpretable in terms of the degree of dysphonia and the spectral slope, respectively. The clinical relevance of the principal components has been confirmed by linear discriminant analysis. © 2010 Elsevier B.V. All rights reserved.


Lobier M.,Pierre Mendès-France University | Dubois M.,Free University of Colombia | Dubois M.,National Fund for Scientific Research | Valdois S.,Pierre Mendès-France University
PLoS ONE | Year: 2013

A steady increase in reading speed is the hallmark of normal reading acquisition. However, little is known of the influence of visual attention capacity on children's reading speed. The number of distinct visual elements that can be simultaneously processed at a glance (dubbed the visual attention span), predicts single-word reading speed in both normal reading and dyslexic children. However, the exact processes that account for the relationship between the visual attention span and reading speed remain to be specified. We used the Theory of Visual Attention to estimate visual processing speed and visual short-term memory capacity from a multiple letter report task in eight and nine year old children. The visual attention span and text reading speed were also assessed. Results showed that visual processing speed and visual short term memory capacity predicted the visual attention span. Furthermore, visual processing speed predicted reading speed, but visual short term memory capacity did not. Finally, the visual attention span mediated the effect of visual processing speed on reading speed. These results suggest that visual attention capacity could constrain reading speed in elementary school children. © 2013 Lobier et al.

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