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See detailImproving the alkalophilic performances of the Xyl1 xylanase from Streptomyces sp S38: Structural comparison and mutational analysis
De Lemos Esteves, Frédéric ULg; Gouders, T.; Lamotte-Brasseur, J. et al

in Protein Science : A Publication of the Protein Society (2005), 14(2), 292-302

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic ... [more ▼]

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic activity is 6. Xyn11 from Bacillus agaradhaerens and XylJ from Bacillus sp. 41M-1 share 85% sequence identity and have been described as highly alkalophilic enzymes. In an attempt to better understand the alkalophilic adaptation of xylanases, the three-dimensional structures of Xyn11 and Xyl1 were compared. This comparison highlighted an increased number of salt-bridges and the presence of more charged residues in the catalytic cleft as well as an eight-residue-longer loop in the alkalophilic xylanase Xyn11. Some of these charges were introduced in the structure of Xyl1 by site-directed mutagenesis with substitutions Y16D, S18E, G50R, N92D, A135Q, E139K, and Y186E. Furthermore, the eight additional loop residues of Xyn11 were introduced in the homologous loop of Xyl1. In addition, the coding sequence of the XylJ catalytic domain was synthesized by recursive PCR, expressed in a Streptomyces host, purified, and characterized together with the Xyl1 mutants. The Y186E substitution inactivated Xyl1, but the activity was restored when this mutation was combined with the G50R or S18E substitutions. Interestingly, the E139K mutation raised the optimum pH of Xyl1 from 6 to 7.5 but had no effect when combined with the N92D substitution. Modeling studies identified the possible formation of an interaction between the introduced lysine and the substrate, which could be eliminated by the formation of a putative salt-bridge in the N92D/E139K mutant. [less ▲]

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See detailImproving the bias/variance tradeoff of decision trees - towards soft tree induction
Geurts, Pierre ULg; Olaru, Cristina; Wehenkel, Louis ULg

in Engineering intelligent systems (2001), 9

One of the main difficulties with standard top down induction of decision trees comes from the high variance of these methods. High variance means that, for a given problem and sample size, the resulting ... [more ▼]

One of the main difficulties with standard top down induction of decision trees comes from the high variance of these methods. High variance means that, for a given problem and sample size, the resulting tree is strongly dependent on the random nature of the particular sample used for training. Consequently, these algorithms tend to be suboptimal in terms of accuracy and interpretability. This paper analyses this problem in depth and proposes a new method, relying on threshold softening, able to significantly improve the bias/variance tradeoff of decision trees. The algorithm is validated on a number of benchmark problems and its relationship with fuzzy decision tree induction is discussed. This sheds some light on the success of fuzzy decision tree induction and improves our understanding of machine learning, in general. [less ▲]

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See detailImproving the catabolic functions in desiccation-tolerant soil bacteria in view of their use in bioaugmentation.
Weekers, F.; Jacques, Ph.; Springael, D. et al

Poster (1998, May 08)

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See detailImproving the catabolic functions in dessication-tolerant soil bacteria in view of their use in bioaugmentation
Weekers, F.; Jacques, Ph.; Springael, D. et al

Poster (1998, May)

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See detailImproving The Catabolic Functions Of Desiccation-Tolerant Soil Bacteria
Weekers, F.; Jacques, P.; Springael, D. et al

in Applied Biochemistry and Biotechnology (1999), 77-9

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See detailImproving the grinding performance in ball mills with a conductive and inductive sensor
Köttgen, Axel ULg; de Haas, Bernard; Keshav, Pratish et al

Poster (2010)

A series of tests were conducted in a South African concentrator on the secondary grinding mill. The results were analysed and provided showed the importance of selecting an optimum density and filling ... [more ▼]

A series of tests were conducted in a South African concentrator on the secondary grinding mill. The results were analysed and provided showed the importance of selecting an optimum density and filling degree of the mill. Moreover, a Sensomag (r) is installed on this mill and the surveys showed that an increase of the density was improving the mixing of balls in the pulp and increasing the grinding performance. [less ▲]

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See detailImproving the performance of low-gain designs for bounded control of linear systems
Grognard, F.; Sepulchre, Rodolphe ULg; Bastin, G.

in Automatica (2002), 38(11), 1777-1782

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See detailImproving the power of out of control states detection in multivariate processes using variable sampling intervals policy
Seif, A.; Faraz, Alireza ULg; Torabian, M.

in Journal of Applied Mathematics (2009), 23

The familiar multivariate process monitoring and control procedure is the Hotelling’s T2 control chart, a direct analog of the univariate shewhart chart. But, its efficiency for detecting small to ... [more ▼]

The familiar multivariate process monitoring and control procedure is the Hotelling’s T2 control chart, a direct analog of the univariate shewhart chart. But, its efficiency for detecting small to moderate shifts in the process mean is poor. To improve the power of chart, this paper presents the variable sampling intervals (VSI) scheme. It is assumed that the length of time the process remains in control has exponential distribution. The chart is modeled using Markov chains and is optimized using genetic algorithm optimization method. The results show that the T2 chart with variable ratio sampling scheme is quicker than the classical one in detecting almost all shifts in the process mean [less ▲]

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See detailImproving the seismic robustness of reinforced concrete frames by using locally hybrid steel-concrete columns
Degée, Hervé ULg; Plumier, André ULg

in Proceedings of the STESSA 2009 Conference (2009)

The proposed concept consists in placing a steel profile with limited size inside the reinforced concrete column of the first level of the building. This profile is not considered for the design and is ... [more ▼]

The proposed concept consists in placing a steel profile with limited size inside the reinforced concrete column of the first level of the building. This profile is not considered for the design and is essen-tially assumed to act as a safety belt activated only in case of deficiencies of the concrete under earthquake action, providing thus the requested robustness and limiting the risk of soft-storey mechanisms even in the most unfavorable conditions. Theoretical, experimental and numerical investigations summarized in the pre-sent contribution are aiming at demonstrating the efficiency of the concept. [less ▲]

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See detailImproving the statement of the corrective security-constrained optimal power flow problem
Capitanescu, Florin ULg; Wehenkel, Louis ULg

in IEEE Transactions on Power Systems (2007), 22(2), 887-889

This letter proposes a formulation of the corrective security-constrained optimal power-flow problem imposing, in addition to the classical post-contingency constraints, existence and viability ... [more ▼]

This letter proposes a formulation of the corrective security-constrained optimal power-flow problem imposing, in addition to the classical post-contingency constraints, existence and viability constraints on the short-term equilibrium reached just after contingency. The rationale for doing so is discussed and supported by two examples. [less ▲]

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See detailImproving training in problem solving skills : Analysis of anesthesists' performance in simulated problem situations
Nyssen, Anne-Sophie ULg; De Keyser, Véronique ULg

in Travail Humain (Le) (1998), 61(4), 387-401

Using a full scale anesthesia simulator, we compare and analyze the responses of anesthesia trainees (second and third year trainees and fourth and fifth year trainees) to 4 simulated problem situations ... [more ▼]

Using a full scale anesthesia simulator, we compare and analyze the responses of anesthesia trainees (second and third year trainees and fourth and fifth year trainees) to 4 simulated problem situations that are very close to a real-world situation in order to establish relationship between these analyses and the contents of medical training cursus. Data were collected from systematic observations and videotaping of simulation sessions and self-confrontation. Several quantitative and qualitative variables were used to compare the performance of subjects: accuracy and speed of diagnosis, type of behaviors, identification and selectivity of diagnostic indices, hypotheses generated, type of reasoning. [less ▲]

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See detailImpuissance érectile: Symptôme aspécifique
Mormont, Christian ULg

in Feuillets Psychiatriques de Liège (1980), 13(1), 5-11

L'impuissance érectile est souvent considérée comme un symptôme simple et banal. Pourtant, il apparaît très vite que la plus grande incertitude plane sur la nature et l'efficacité des facteurs ... [more ▼]

L'impuissance érectile est souvent considérée comme un symptôme simple et banal. Pourtant, il apparaît très vite que la plus grande incertitude plane sur la nature et l'efficacité des facteurs étiologiques supposés. La méconnaissance de certains facteurs, leur multiplicité, les interactions complexes qui les unissent, l'aspécificité du symptôme ne permettent guère d'aboutir à une conviction raisonnable. Ce problème se pose également sur le plan organique et sur le plan psychique. En fait, il semblerait que chacune des diverses théories explicatives soit adéquate dans des cas particuliers mais qu'aucune ne soit généralisable, contrairement à ce que beaucoup d'auteurs et praticiens font. [less ▲]

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See detailL'impuissance érective: Approche descriptive et pronostique au moyen du Rorschach
Mormont, Christian ULg

in Cahiers de Sexologie Clinique (1985), 11(65), 349-353

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See detailL'impuissance érective: Aspects psychologiques
Mormont, Christian ULg

in Revue Médicale de Liège (1979), 34(17), 712-714

Detailed reference viewed: 5 (0 ULg)