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See detailHow do music experts and non-experts evaluate the vocal accuracy of operatic singing voices?
Larrouy, Pauline ULg; Nowak, Marion; Morsomme, Dominique ULg

Conference (2013, August 22)

Professional singers are expected to sing in tune. However, when an operatic singing technique is employed, the objective measurement of the vocal accuracy (i.e. pitch interval deviation) shows ... [more ▼]

Professional singers are expected to sing in tune. However, when an operatic singing technique is employed, the objective measurement of the vocal accuracy (i.e. pitch interval deviation) shows particularly low scores, whatever the melody performed. This study focuses on the perceptual judgment of operatic voices in order to observe the evaluation process of singing voice accuracy by music experts and non-experts. In addition, this study aims to better understand the relationship between the subjective and objective measurements of operatic singing voices. 22 music experts and 22 non-experts paired in age and gender participated in a test and a retest (8 to 15 days in between). Fourteen sung performances performed by professional operatic singers were presented with a pairwise comparison paradigm. The participants were asked to indicate the most “in tune” melody for each pair (N = 91). The performances obtained thus a ranking by each judge. In addition, the 14 sung performances were objectively analyzed in order to confront the objective measurement of singing voice accuracy with the perceptual rating of the judges. Computing the variances of rank differences between the test and the retest, we observed that 20 music experts and 16 non-experts were consistent in their judgments. Among each group, the correlations between consistent raters were positive. However, 67.38% of these correlations were significant (p < .05) for the music experts whereas only 42.10% were significant for the non-experts. In addition, no relationship occurred between the objective measurements (from 9.5 to 115.5 cents, M = 40.57, SD = 34.42) and the perceptual ratings, except for two music experts. This study highlights the consistency of a judge when rating operatic singing voices and the difference between music experts and non-experts concerning the inter-judges reliability. Despite the fact that the majority of the music experts used similar strategies to evaluate the vocal accuracy of operatic voices, their judgment was obviously not linked with the objective measurement of vocal accuracy. This finding supports the tolerance of music expert listeners regarding the singing voice accuracy of operatic singers. Furthermore, this study provides some directions about the perception of operatic singing voices, which are particularly complex. [less ▲]

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See detailHow do paedomorphic newts cope with lake drying?
Denoël, Mathieu ULg

in Ecography (2003), 26(4), 405-410

Paedomorphosis, in which adult individuals retain larval traits, is widespread in newts and salamanders. Most evolutionary models predict the maintenance of this life-history trait in favourable aquatic ... [more ▼]

Paedomorphosis, in which adult individuals retain larval traits, is widespread in newts and salamanders. Most evolutionary models predict the maintenance of this life-history trait in favourable aquatic habitats surrounded by hostile terrestrial environments. Nevertheless, numerous ponds inhabited by paedomorphic individuals are unpredictable and temporary. In an experimental framework, I showed that paedomorphic newts were able to metamorphose and thus survive in the absence of water. However, the mere decrease of water level or the life space do not seem to induce metamorphosis in paedomorphs. On the contrary, drying up induces almost all individuals to move on land and after that to colonize other aquatic sites located nearby. Such terrestrial migrations allow survival in drying conditions without metamorphosis as long as the distances of terrestrial migration are short. These results are consistent with the presence of paedomorphs in drying ponds and are in favor of classic optimality models predicting metamorphosis in unfavorable environments. [less ▲]

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See detailHow Do Performance Measures Perform
Hübner, Georges ULg

in Journal of Portfolio Management (2007), 33(4), 64-74

The article presents a discussion on how various performance measures actually perform when used in investment portfolio management. The author discusses the empirical quality of performance measures such ... [more ▼]

The article presents a discussion on how various performance measures actually perform when used in investment portfolio management. The author discusses the empirical quality of performance measures such as information ratio (IR), focusing on directional managed portfolios, the Treynor ratio, and an empirical methodology that allows many of the usual errors associated with ratios to be avoided. The author also discusses multi-index models, style-based mutual funds, and style-adjusted performance. [less ▲]

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See detailHow do preschool teacher's requests influence children's behaviors ?
Crahay, Marcel ULg; Delhaxhe, Arlette

in Teaching & Teacher Education (1991), 7(3), 221-239

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See detailHow do Rhizobacterial Volatiles Influence Root System Architecture, Biomass Production and Allocation of the Model Grass Brachypodium distachyon?
Delaplace, Pierre ULg; Ormeño - Lafuente, Elena; Nguyen, Minh ULg et al

Conference (2016, January 12)

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile ... [more ▼]

Plant growth-promoting rhizobacteria are increasingly considered as a complement of conventional inputs in agricultural systems. Their effects on their host plants are diverse and include volatile-mediated growth enhancement. The present study aims at assessing the effects of bacterial volatile production on the biomass production and the root system architecture of Brachypodium distachyon (L.) Beauv. (line Bd-21). An in vitro experimental set-up allowing plant-bacteria interaction through the gaseous phase without any physical contact was used to screen 19 bacterial strains for their growth promotion ability over a 10-day cocultivation period. Using principal component analysis followed by hierarchical clustering and two-way analysis of variance, five groups of bacteria were defined and characterized based on their combined influence on biomass production and root system architecture. The observed effects range from unchanged to highly increased biomass production coupled with increased root length and branching. Primary root length was only increased by the volatile compounds emitted by Enterobacter cloacae JM22 and Bacillus pumilus T4. Overall, the most significant results were obtained with Bacillus subtilis GB03 which induced a 81% increase in total biomass and enhanced total root length, total secondary root length and total adventitious root length by 88, 196 and 473% respectively. The analysis of the emission kinetics of bacterial volatile organic compounds is underway and should lead to the identification of volatile compounds candidates responsible for the observed growth promotion effects. Taking into account the inherent characteristics of our in vitro system, the next experimental steps are identified and discussed from a fundamental and applied viewpoint. [less ▲]

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See detailHow do temperate bryophytes face the challenge of a changing environment? Lessons from the past and predictions for the future
Desamore, Aurélie ULg; Laenen, Benjamin ULg; Stech, M. B et al

in Global Change Biology (2012), 18(9), 2915-2924

Bryophytes are a group of early land plants, whose specific ecophysiological and biological features, including poikilohydry, sensitivity to moderately high temperature and high dispersal ability, make ... [more ▼]

Bryophytes are a group of early land plants, whose specific ecophysiological and biological features, including poikilohydry, sensitivity to moderately high temperature and high dispersal ability, make them ideal candidates for investigating the impact of climate changes. Employing a combined approach of species distribution modelling (SDM) and molecular phylogeography in the temperate moss Homalothecium sericeum, we explore the significance of the Mediterranean refugia, contrasting the southern and northern refugia hypotheses, determine the extent to which recolonization of previously glaciated areas has been facilitated by the high dispersal ability of the species and make predictions on the extent to which it will be impacted by ongoing climate change. The Mediterranean areas exhibit the highest nucleotidic diversities and host a mixture of ancestral, endemic and more recently derived haplotypes. Extra-Mediterranean areas exhibit low genetic diversities and Euro-Siberian populations display a significant signal of expansion that is identified to be of Euro-Siberian origin, pointing to the northern refugia hypothesis. The SDMs predict a global net increase in range size owing to ongoing climate change, but substantial range reductions in southern areas. Presence of a significant phylogeographical signal at different spatial scales suggests, however, that dispersal limitations might constitute, as opposed to the traditional view of spore-producing plants as efficient dispersers, a constraint for migration. This casts doubts about the ability of the species to face the massive extinctions predicted in the southern areas, threatening their status of reservoir of genetic diversity. © 2012 Blackwell Publishing Ltd. [less ▲]

Detailed reference viewed: 48 (4 ULg)
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See detailHow do we perceive vocal pitch accuracy during singing?
Larrouy, Pauline ULg; Pfordresher, Peter Q

Conference (2014, March 03)

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See detailHow do women entrepreneurs use the virtual network Facebook? The impact of gender
Constantinidis, Christina ULg

in International Journal of Entrepreneurship & Innovation (2011), 12(4), 257-269

This paper examines the views and attitudes of a sample of 228 female entrepreneurs towards the virtual social network Facebook. It identifies the main trends and uses statistical analysis to evaluate the ... [more ▼]

This paper examines the views and attitudes of a sample of 228 female entrepreneurs towards the virtual social network Facebook. It identifies the main trends and uses statistical analysis to evaluate the impact of their gendered sector of activity and of their self-perception on their view of this network as a response to gender-related difficulties and their use of it in relation to their activities and objectives. The study further investigates how Facebook may encourage and support women’s networks as well as benefit women-owned businesses. It highlights certain implications for public and private initiatives and underlines the potential of this and other virtual social networking sites for women’s entrepreneurship. [less ▲]

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See detailHow do “scoops” influence the perception of singing accuracy?
Larrouy, Pauline ULg; Pfordresher, Peter

Conference (2015, August)

When we listen to a singer, a large amount of time-varying information is available on which evaluations of accuracy may be based. Most analyses of singing accuracy focus on relatively steady portions of ... [more ▼]

When we listen to a singer, a large amount of time-varying information is available on which evaluations of accuracy may be based. Most analyses of singing accuracy focus on relatively steady portions of sung notes, eliminating “scoops” of pitch that often occur at note beginnings and endings. However, it is likely that these scoops contribute to judgments of accuracy. We report results of three experiments designed to address the relative contribution of these scoops in contrast to a steady central portion of sung notes. Participants rated the pitch accuracy of 4-tone melodies where the 3rd tone was manipulated with respect to its center region (either correct, 50 cents sharp, or 50 cents flat) as well as the presence of a scoop at the start and/or the end of the tone, varying with respect to direction. We were particularly interested in contrasting scoops that maintained ‘continuity’ between tones (e.g., scooping up for an ascending interval) versus those that highlighted distinctions (the opposite). Further analyses evaluated whether reactions to scoops indicate a tendency to perceive the average pitch across the entire tone, or to treat scoops versus the tone’s center as separate features. Results suggest that listeners respond to scoops in a way that goes beyond role in forming the average pitch across a tone. Listeners respond differently to scoops at the beginning versus the end, showing more sensitivity to ending scoops. Furthermore, listeners do not necessarily prefer scoops that preserve continuity. Taken together, these results demonstrate that continuous time-varying pitch information is an important indicator of perceived singing accuracy, and should be considered more fully when assessing singing ability. [less ▲]

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See detailHow does an ice block assembly melt?
Dorbolo, Stéphane ULg; Ludewig, François ULg; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2012)

Detailed reference viewed: 40 (17 ULg)
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See detailHow does elicitor and antimicrobial fengycin interact with plasma membranes of sensitive cells ?
Nasir, Mehmet Nail ULg; Eeman, Marc; Lins, Laurence ULg et al

Conference (2012, April)

Fengycin is characterized by its strong antifungal and low hemolytic activities. It has also been recently demonstrated that it has plant elicitor properties and is also able to enhance the elicitors’ ... [more ▼]

Fengycin is characterized by its strong antifungal and low hemolytic activities. It has also been recently demonstrated that it has plant elicitor properties and is also able to enhance the elicitors’ activity of surfactin. The cell target of its biological activities is supposed to be plasma membrane. In spite of these interesting biological activities, fengycin has not been extensively investigated probably because of the difficulties related to its production. In a first time; we have characterized the interfacial properties of fengycin by tensiometry measurements and demonstrated that this surface activity was pH-dependent. In a second time; we have investigated the interactions of the lipopeptide with membrane lipids using model membranes such as Langmuir monolayers and multilammelar vesicles (MLVs). Our results indicate that the lipopeptide was able to penetrate into different lipid monolayers showing a preference for sterol-containing monolayers. In order to better understand the mechanism of the interactions of fengycin with membranes at the molecular level, MLVs with or without fengycin have been analyzed by spectroscopic techniques. We have shown that conformational changes of the lipopeptide occurred in the presence of lipids and they were more significant in the presence of sterol. Moreover, tyrosine residues of the lipopeptide seem to play an important role in these interactions. In conclusion, we have determined that the surface-active behavior as well as the conformation of fengycin depends on its environment. We have also showed that the lipopeptide does not interact with all class of lipids in the same way and presents a preference for sterols. The presence of key groups within peptide cycle has also been supposed for the biological activities of the lipopeptide. [less ▲]

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See detailHow does engagement in reading predict digital reading proficiency among 15 year-olds?
Lafontaine, Dominique ULg; Monseur, Christian ULg; Baye, Ariane ULg

Conference (2012, September)

In PISA 2009, 19 countries took part to an optional assessment of digital reading. In each country, a subsample of 15 year-olds was administered not only the paper and pencil PISA test, but also different ... [more ▼]

In PISA 2009, 19 countries took part to an optional assessment of digital reading. In each country, a subsample of 15 year-olds was administered not only the paper and pencil PISA test, but also different reading tasks online. The aim of our study is to investigate the relationships between engagement in reading, especially online reading practices, and digital reading proficiency of 15 year-olds in the 11 European countries which took part to this option (11 out of 19). [less ▲]

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See detailHow does gender socialisation influence teenagers' behaviors ? : Contribution of ISRD-2 and ISRD-3 to this question
Gavray, Claire ULg

Conference (2014, November 21)

In both gender groups, young people entering the spiral of violence negatively often react against personal insecurity, against a hostile and little promising environment. But those environments still ... [more ▼]

In both gender groups, young people entering the spiral of violence negatively often react against personal insecurity, against a hostile and little promising environment. But those environments still differ between girls and boys according to the sphere which remains the most valorized, 'suitable' for them (public and competitive sphere for the boys, family and emotional sphere for the girls). ISRD data allow to show links between, on one side, the production of not authorized and violent behaviors and, on the other side, gendered concrete life, gendered attitudes and values. The theory of the societal vulnerability (Walgrave, Vettenburg) and the theory of recognition (Honneth) are confirmed. [less ▲]

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See detailHow does governmental versus private venture capital backing affect a firm's efficiency? Evidence from Belgium
Alperovych; Hübner, Georges ULg; Lobet, Fabrice

in Journal of Business Venturing (2015), 30

We investigate the implications of venture capital (VC) investor type (government or private) on the operating efficiency of a sample of 515 Belgian portfolio firms up to 3 years after the investment. We ... [more ▼]

We investigate the implications of venture capital (VC) investor type (government or private) on the operating efficiency of a sample of 515 Belgian portfolio firms up to 3 years after the investment. We find that the government VC-backed firms display significant reductions in productivity. No significant differences in efficiency are found in firms backed by private VC compared with their non-VC-backed peers. Finally, significant reductions in efficiency exist in targets of government VC compared to their non-VC-backed peers. [less ▲]

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See detailHow Does Pollen Chemistry Impact Development and Feeding Behaviour of Polylectic Bees?
Vanderplanck, Maryse; Moerman, Romain; Rasmont, Pierre et al

in PLoS ONE (2014), 9(1), 9

Larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. While oligolectic species forage on pollen from a single family of ... [more ▼]

Larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. While oligolectic species forage on pollen from a single family of host plants, polylectic bees, such as bumblebees, collect pollen from many families of plants. These polylectic species contend with interspecific variability in essential nutrients of their host-plants but we have only a limited understanding of the way in which chemicals and chemical combinations influence bee development and feeding behaviour. In this paper, we investigated five different pollen diets (Calluna vulgaris, Cistus sp., Cytisus scoparius, Salix caprea and Sorbus aucuparia) to determine how their chemical content affected bumblebee colony development and pollen/syrup collection. Three compounds were used to characterise pollen content: polypeptides, amino acids and sterols. Several parameters were used to determine the impact of diet on micro-colonies: (i) Number and weight of larvae (total and mean weight of larvae), (ii) weight of pollen collected, (iii) pollen efficacy (total weight of larvae divided by weight of the pollen collected) and (iv) syrup collection. Our results show that pollen collection is similar regardless of chemical variation in pollen diet while syrup collection is variable. Micro-colonies fed on S. aucuparia and C. scoparius pollen produced larger larvae (i.e. better mates and winter survivors) and fed less on nectar compared to the other diets. Pollen from both of these species contains 24-methylenecholesterol and high concentrations of polypeptides/total amino acids. This pollen nutritional “theme” seems therefore to promote worker reproduction in B. terrestris micro-colonies and could be linked to high fitness for queenright colonies. As workers are able to selectively forage on pollen of high chemical quality, plants may be evolutionarily selected for their pollen content, which might attract and increase the degree of fidelity of generalist pollinators, such as bumblebees. [less ▲]

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See detailHow does the age of hoverfly females affect their reproduction?
Almohamad, Raki; Verheggen, François ULg; Francis, Frédéric ULg et al

Conference (2007)

Detailed reference viewed: 10 (2 ULg)