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See detailInteractions of cryptolepine and neocryptolepine with unusual DNA structures
Guittat, Lionel; Alberti, Patrizia; Rosu, Frédéric ULg et al

in Biochimie (2003), 85(5), 535-547

Cryptolepine, the main alkaloid present in the roots of Cryptolepis sanguinolenta, presents a large spectrum of biological properties. It has been reported to behave like a DNA intercalator with a ... [more ▼]

Cryptolepine, the main alkaloid present in the roots of Cryptolepis sanguinolenta, presents a large spectrum of biological properties. It has been reported to behave like a DNA intercalator with a preference for GC-rich sequences. In this study, dialysis competition assay and mass spectrometry experiments were used to determine the affinity of cryptolepine and neocryptolepine for DNA structures among duplexes, triplexes, quadruplexes and single strands. Our data confirm that cryptolepine and neocryptolepine prefer GC over AT-rich duplex sequences, but also recognize triplex and quadruplex structures. These compounds are weak telomerase inhibitors and exhibit a significant preference for triplexes over quadruplexes or duplexes. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Societe francaise de biochimie et biologic moleculaire. All rights reserved. [less ▲]

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See detailTransient stability emergency control combining open-loop and closed-loop technique
Ruiz-Vega, Daniel; Glavic, Mevludin; Ernst, Damien ULg

in Proceedings of the IEEE Power Engineering Society General Meeting, 2003 (2003)

An on-line transient stability emergency control approach is proposed, which couples an open-loop and a closed-loop emergency control technique. The open-loop technique uses on-line transient stability ... [more ▼]

An on-line transient stability emergency control approach is proposed, which couples an open-loop and a closed-loop emergency control technique. The open-loop technique uses on-line transient stability assessment in order to adapt the settings of automatic system protection schemes to the current operating conditions. On the other hand, the closed-loop technique uses measurements in order to design and trigger countermeasures, after the contingency has actually happened, then to continue monitoring in a closed-loop fashion. The approach aims at combining advantages of event-based and measurement-based system protection schemes, namely, speed of action and robustness with respect to uncertainties in system modeling. It can also comply with economic criteria. [less ▲]

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See detailA reinforcement learning based discrete supplementary control for power system transient stability enhancement
Glavic, Mevludin; Ernst, Damien ULg; Wehenkel, Louis ULg

in Proceedings of the 12th Intelligent Systems Application to Power Systems Conference (ISAP 2003) (2003)

This paper proposes an application of a Reinforcement Learning (RL) method to the control of a dynamic brake aimed to enhance power system transient stability. The control law of the resistive brake is in ... [more ▼]

This paper proposes an application of a Reinforcement Learning (RL) method to the control of a dynamic brake aimed to enhance power system transient stability. The control law of the resistive brake is in the form of switching strategies. In particular, the paper focuses on the application of a model based RL method, known as prioritized sweeping, a method proven to be suitable in applications in which computation is considered to be cheap. The curse of dimensionality problem is resolved by the system state dimensionality reduction based on the One Machine Infinite Bus (OMIB) transformation. Results obtained by using a synthetic four-machine power system are given to illustrate the performances of the proposed methodology. [less ▲]

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See detailIteratively extending time horizon reinforcement learning
Ernst, Damien ULg; Geurts, Pierre ULg; Wehenkel, Louis ULg

in Machine Learning: ECML 2003, 14th European Conference on Machine Learning (2003)

Reinforcement learning aims to determine an (infinite time horizon) optimal control policy from interaction with a system. It can be solved by approximating the so-called Q-function from a sample of four ... [more ▼]

Reinforcement learning aims to determine an (infinite time horizon) optimal control policy from interaction with a system. It can be solved by approximating the so-called Q-function from a sample of four-tuples (x(t), u(t), r(t), x(t+1)) where x(t) denotes the system state at time t, ut the control action taken, rt the instantaneous reward obtained and x(t+1) the successor state of the system, and by determining the optimal control from the Q-function. Classical reinforcement learning algorithms use an ad hoc version of stochastic approximation which iterates over the Q-function approximations on a four-tuple by four-tuple basis. In this paper, we reformulate this problem as a sequence of batch mode supervised learning problems which in the limit converges to (an approximation of) the Q-function. Each step of this algorithm uses the full sample of four-tuples gathered from interaction with the system and extends by one step the horizon of the optimality criterion. An advantage of this approach is to allow the use of standard batch mode supervised learning algorithms, instead of the incremental versions used up to now. In addition to a theoretical justification the paper provides empirical tests in the context of the "Car on the Hill" control problem based on the use of ensembles of regression trees. The resulting algorithm is in principle able to handle efficiently large scale reinforcement learning problems. [less ▲]

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See detailEstimating internal pelvic sizes using external body measurements in the double-muscled Belgian Blue beef breed
Coopman, F.; de Smet, S.; Gengler, Nicolas ULg et al

in Animal Science (2003), 76(Part 2), 229-235

In the double-muscled (DM) Belgian Blue beef (BBB) breed, caesarean section (CS) is being applied systematically as a management tool to prevent dystocia. As a matter of fact, CS is the only possible way ... [more ▼]

In the double-muscled (DM) Belgian Blue beef (BBB) breed, caesarean section (CS) is being applied systematically as a management tool to prevent dystocia. As a matter of fact, CS is the only possible way of calving in the breed. High birth weight and a relatively small pelvic area are the main causes of dystocia and, in the DM-BBB breed, the reasons for the systematically applied CS. Selection for lower birth weight and larger pelvic sizes might reduce dystocia and routine CS. Few data on inner pelvic sizes of pedigree animals are available. Using external measurements to estimate the inner pelvic sizes might be an option to resolve this problem. In this study, animals of the DM-BBB breed were measured and weighed on farms and in abattoirs. External and internal pelvic sizes increased with live weight and age of the animals. Gender had a significant influence on inner pelvic traits. Increased muscular conformation was associated with decreased inner pelvic dimensions. Models with weight, gender, age, withers height and outer pelvic width (TcTc) can be used to estimate inner pelvic sizes (R-2 between 0.35 and 0.77). The estimated inner pelvic sizes can then be used to genetically evaluate pelvic traits in the DM-BBB breed. Improving weight, withers height and TcTc width in combination with lowering muscular conformation may help to decrease the high rate of caesarean section in the DM-BBB. [less ▲]

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See detailWithin-herd effects of age at test day and lactation stage on test-day yields
Bormann, J.; Wiggans, G. R.; Druet, Tom ULg et al

in Journal of Dairy Science (2003), 86(11), 3765-3774

Variance ratios were estimated for random within-herd effects of age at test day and lactation stage, on test-day yield and somatic cell score to determine whether including these effects would improve ... [more ▼]

Variance ratios were estimated for random within-herd effects of age at test day and lactation stage, on test-day yield and somatic cell score to determine whether including these effects would improve the accuracy of estimation. Test-day data starting with 1990 calvings for the entire US Jersey population and Holsteins from California, Pennsylvania, Wisconsin, and Texas were analyzed. Test-day yields were adjusted for across-herd effects using solutions from a regional analysis. Estimates of the relative variance ( fraction of total variance) due to within-herd age effects were small, indicating that regional adjustments for age were adequate. The relative variances for within-herd lactation stage were large enough to indicate that accuracy of genetic evaluations could be improved by including herd stage effects in the model for milk, fat, and protein, but not for somatic cell score. Because the within-herd lactation stage effect is assumed to be random, the effect is regressed toward the regional effects for small herds, but in large herds, lactation curves become herd specific. Model comparisons demonstrated the greater explanatory power of the model with a within-herd-stage effect as prediction error standard deviations were greater for the model without this effect. The benefit of the within-herd-stage effects was confirmed in a random regression model by comparing variance components from models with and without random within-herd regressions and through log-likelihood ratio tests. [less ▲]

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See detailVolumen-Flussmessung mit "Colour Velocity Imaging (CVI)": Technik der Messung in der intrahepatischen fetalen Vena umbilicalis
Chantraine, Frédéric ULg; Reihs, Tanja; Henrich, Wolfgang et al

in Zentralblatt für Gynakologie (2003), 125

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See detailInformation literacy in Belgium : An overview by the Edudoc Group
Thirion, Paul ULg; Pochet, Bernard ULg

in Basili, Carla (Ed.) Information literacy in Europe : a first insight into the state of art of information literacy in the European Union (2003)

When we were invited to describe the situation on information literacy (hereafter, IL) in Belgium, it appeared to us that numerous aspects had to be treated. The present document will include a rapid ... [more ▼]

When we were invited to describe the situation on information literacy (hereafter, IL) in Belgium, it appeared to us that numerous aspects had to be treated. The present document will include a rapid analysis of the Belgian situation and a description of the Edudoc Group. During this description we will trace ten years of activity and present several IL projects, in particular, a recent one concerning distance learning that is currently under development. [less ▲]

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See detailThe Sahelian drought may have ended during the 1990s
Ozer, Pierre ULg; Erpicum, Michel ULg; Demarée, Gaston et al

in Hydrological Sciences Journal = Journal des Sciences Hydrologiques (2003), 48(3), 489-492

The severe drought that affects the Sahel since the late 1960s has been very closely studied and monitored during the last three decades. Recently, after several wet years, it was questioned from a ... [more ▼]

The severe drought that affects the Sahel since the late 1960s has been very closely studied and monitored during the last three decades. Recently, after several wet years, it was questioned from a statistical point of view whether the drought was over. The conclusions of a recent study were that the rainfall deficit was not over at the end of 2000 and that the drought continues. The analysis of the change points in the station rainfall time series suggests differentiating these findings. There is now growing evidence that there is a potential shift towards a more humid state. However, the present analysis shows that the assumption that a significant increase in rainfall may have occurred around the early 1990s could only be verified at the customary confidence level in about 10 years from now. [less ▲]

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See detailSelection of the most efficient wavelength bands for 'Jonagold' apple sorting
Kleynen, O.; Leemans, Vincent ULg; Destain, Marie-France ULg

in Postharvest Biology & Technology (2003), 30(3), 221-232

This paper presents a method based on quadratic discriminant analysis to select the best filters for detecting a wide range of defects in 'Jonagold' apple fruit using a multi-spectral vision system ... [more ▼]

This paper presents a method based on quadratic discriminant analysis to select the best filters for detecting a wide range of defects in 'Jonagold' apple fruit using a multi-spectral vision system. Reflectance spectra of damaged and sound tissue were recorded using a visible/NIR spectrometer. Analysed defects consisted of scald, hail damage (with and without skin perforation), limb rubs, russets, scab tissue, frost damage, rot, visible flesh damage and recent bruises. Camera filter effects were approximated by summing the reflectances of all the wavelengths within the filter bandwidth. Combinations of three and four filters were tested and evaluated for discriminating damaged tissues from healthy ones. If a three-filter combination appeared sufficient to detect most of the damaged tissue, a four-filter combination should be considered for the complete sorting automation of this bicolour apple variety. A fourth filter was necessary to quantify the ratio between the blush and ground colours. Regarding recent bruise defects which represented the major difficulty, an image segmentation algorithm based on local contrast variations can enhance their detection. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailAnalysis of soil and crop properties for precision agriculture for winter wheat
Vrindts, Els; Reyniers, Marieke; Darius, Paul et al

in Biosystems Engineering (2003), 85(2), 141-152

In a precision farming research project financed by the Belgian Ministry of Small Trade and Agriculture, the methods of precision agriculture are tested on grain fields with a view of implementation of ... [more ▼]

In a precision farming research project financed by the Belgian Ministry of Small Trade and Agriculture, the methods of precision agriculture are tested on grain fields with a view of implementation of precision agriculture methods in Belgian field agriculture. The project encompasses methods for automatic information gathering on soil and crop and analysis of this data for management of within-field variability. Automatic information capturing is combined with traditional data sources of soil sample analysis and crop observations. The measurements and part of the results on one particular field in Sauvenière are presented here. Five nitrogen management strategies were compared, but the resulting differences in nitrogen dose were small and did not lead to significantly different yield results. The yield results were correlated to topography-related variations in soil texture and chemical components and to crop reflectance measurements in May. [less ▲]

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See detailStructural Optimization of the Blanc Pain Flood Control Gate
Rigo, Philippe ULg; Vercruysse, S.; Sarghiuta, R.

in Bulletin scientifique de l'UTCB (2003)

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See detailSensitivity analysis on ultimate strength of aluminium stiffened panels
Rigo, Philippe ULg; Sarghiuta, B.; Estefen, S. et al

in Marine Structures (2003)

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See detailMR2001084,Advanced electromagnetism and vacuum physics, Cornille, Patrick
Rochus, Pierre ULg

in Mathematical Reviews [=MR] (2003)

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See detailDevelopment Of Real-Time Pcr For The Rapid Detection Of Episomal Banana Streak Virus (Bsv)
Delanoy, Martine; Salmon, Marc ULg; Kummert, Jean et al

in Plant Disease (2003), 87(1), 33-38

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See detailHorizontal And Vertical Co2 Advection In A Sloping Forest
Aubinet, Marc ULg; Heinesch, Bernard ULg; Yernaux, Michel ULg

in Boundary-Layer Meteorology (2003), 108(3),

Detailed reference viewed: 17 (2 ULg)