How do ladybirds and syrphids respond to aphids in the field?
; Doucet, Jean-Louis ;
in Bulletin OILB/SROP = IOBC/WPRS Bulletin (1994), 17(4),Detailed reference viewed: 13 (2 ULg)
How do music experts and non-experts evaluate the vocal accuracy of operatic singing voices?
Larrouy, Pauline ; ; Morsomme, Dominique
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 ▲]Detailed reference viewed: 26 (4 ULg)
How do paedomorphic newts cope with lake drying?
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 ▲]Detailed reference viewed: 121 (8 ULg)
How Do Performance Measures Perform
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 ▲]Detailed reference viewed: 31 (7 ULg)
How do preschool teacher's requests influence children's behaviors ?
Crahay, Marcel ;
in Teaching & Teacher Education (1991), 7(3), 221-239Detailed reference viewed: 18 (2 ULg)
How do temperate bryophytes face the challenge of a changing environment? Lessons from the past and predictions for the future
Desamore, Aurélie ; Laenen, Benjamin ; 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: 21 (2 ULg)
How do users formulate their queries? A morpho-syntactic analysis
Fairon, Nicolas ; Brouwir, Christine ; Durieux, Nancy et al
Conference (2008)Detailed reference viewed: 25 (1 ULg)
How do we perceive vocal pitch accuracy during singing?
Larrouy, Pauline ;
Scientific conference (2014, March 03)Detailed reference viewed: 9 (0 ULg)
How do women entrepreneurs use the virtual network Facebook? The impact of gender
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 ▲]Detailed reference viewed: 93 (5 ULg)
How does elicitor and antimicrobial fengycin interact with plasma membranes of sensitive cells ?
Nasir, Mehmet Nail ; ; Lins, Laurence 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 ▲]Detailed reference viewed: 113 (16 ULg)
How does engagement in reading predict digital reading proficiency among 15 year-olds?
Lafontaine, Dominique ; Monseur, Christian ; Baye, Ariane
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 ▲]Detailed reference viewed: 43 (4 ULg)
How does engagement in reading predict digital reading proficiency among 15 years-olds ?
Baye, Ariane ; Lafontaine, Dominique ; Monseur, Christian
Conference (2012, April 15)Detailed reference viewed: 8 (0 ULg)
How Does Pollen Chemistry Impact Development and Feeding Behaviour of Polylectic Bees?
; ; 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 ▲]Detailed reference viewed: 14 (0 ULg)
How does polytheism work?
Pirenne-Delforge, Vinciane ;
in Eidinow, Esther; Kindt, Julia (Eds.) Oxford Handbook of Ancient Greek Religion (in press)
Trying to describe polytheism is a difficult enterprise because the whole system can be seen as a complex structure, each element of which (a deity with its proper name) is both itself a complex set of ... [more ▼]
Trying to describe polytheism is a difficult enterprise because the whole system can be seen as a complex structure, each element of which (a deity with its proper name) is both itself a complex set of prerogatives, and at the same time, must be considered in concert with the other elements. After a brief historiographical overview, this paper focuses on the first aspect by using the notion of ‘network’ as a metaphor to refer to the complexity of the ancient Greek gods. It provides two case studies, of the Moirai and the goddess Hera. The paper concludes that polytheism can be described if one conceptualises the complexity of the gods—their unity and diversity—together at every level (Panhellenic and local, cult and myths, and so on). [less ▲]Detailed reference viewed: 15 (0 ULg)
How does the age of hoverfly females affect their reproduction?
; Verheggen, François ; Francis, Frédéric et al
Conference (2007)Detailed reference viewed: 8 (2 ULg)
How does the age of hoverfly females affect their reproduction?
; Verheggen, François ; Francis, Frédéric et al
in Communications in Agricultural and Applied Biological Sciences (2007), 72(3),Detailed reference viewed: 28 (5 ULg)
How does the efficacy of Protelos translate into patient benefits ?
in Osteoporosis International (2009, March), 20(Suppl.1), 178Detailed reference viewed: 27 (1 ULg)
How does the ocean surrounding the Greenland ice sheet impact its surface mass balance ?
; Watelet, Sylvain ; Fettweis, Xavier et al
Poster (2013, April)Detailed reference viewed: 16 (6 ULg)
How does the organizational context influence the Competitive Intelligence process among Walloon SMEs?
Master's dissertation (2012)
In this increasingly turbulent, global and competitive context, it becomes critical for companies to create and sustain a competitive advantage. Competitive Intelligence (CI), defined as “the process by ... [more ▼]
In this increasingly turbulent, global and competitive context, it becomes critical for companies to create and sustain a competitive advantage. Competitive Intelligence (CI), defined as “the process by which organizations gather information on competitors and the competitive environment [...]” (Wright, Eid & Fleisher, 2009, p.942), can contribute to do so by enabling managers to be aware of and respond to changes in their competitive environment. The CI process includes four steps: (a) planning and focus, (b) data collection, (c) data analysis and (d) communication. First, this paper assesses the level of deployment of CI among Walloon SMEs. Second, it examines the influence of context variables on the CI process. A questionnaire was distributed to 423 Walloon SMEs’ executives, of whom 81 answered. SMEs’ executives were surveyed about their companies’ CI practices as well as their perception of their company’s formal structure, employee involvement and organizational awareness. We found that Walloon SMEs are not very active to conduct CI effectively. Indeed, while Walloon SMEs have recognized that, theoretically, CI is a necessary activity for maintaining a competitive advantage, in practice, most of them do not have yet a well-established CI process in their company. Then, we established the influence of the context in which CI takes place on the success of the CI process. Specifically, we supported that better formal structure, employee involvement and organizational awareness improve the CI process. Finally, we examined the impact of two extra potential antecedents, namely the innovation orientation and the company’s size. We found that innovation-oriented companies tend to exploit CI more than followers. The results lead to several recommendations for SMEs. First, managers should be aware that CI is critical for their company’s survival since the context in which they operate is increasingly competitive. Second, businesses, especially those that are innovation-oriented, should note that an improvement in their formal infrastructure, organizational awareness and employee involvement processes could significantly enhance their CI efficiency. [less ▲]Detailed reference viewed: 95 (14 ULg)